diff --git a/.gitignore b/.gitignore
index 90b078fc94f..40c473d13dd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -59,3 +59,11 @@ internal/
 .idea
 yarn.lock
 .parallelperf.*
+tests/cases/user/*/package-lock.json
+tests/cases/user/*/node_modules/
+tests/cases/user/*/**/*.js
+tests/cases/user/*/**/*.js.map
+tests/cases/user/*/**/*.d.ts
+!tests/cases/user/zone.js/
+!tests/cases/user/bignumber.js/
+!tests/cases/user/discord.js/
diff --git a/.travis.yml b/.travis.yml
index d24e155b580..06e912c55f5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,8 +2,8 @@ language: node_js
 
 node_js:
   - 'stable'
+  - '8'
   - '6'
-  - '4'
 
 sudo: false
 
diff --git a/Gulpfile.ts b/Gulpfile.ts
index 5a27eb52b32..aedde5c33d9 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -46,14 +46,15 @@ const cmdLineOptions = minimist(process.argv.slice(2), {
     boolean: ["debug", "inspect", "light", "colors", "lint", "soft"],
     string: ["browser", "tests", "host", "reporter", "stackTraceLimit", "timeout"],
     alias: {
-        b: "browser",
-        d: "debug", "debug-brk": "debug",
-        i: "inspect", "inspect-brk": "inspect",
-        t: "tests", test: "tests",
-        r: "reporter",
-        c: "colors", color: "colors",
-        f: "files", file: "files",
-        w: "workers",
+        "b": "browser",
+        "d": "debug", "debug-brk": "debug",
+        "i": "inspect", "inspect-brk": "inspect",
+        "t": "tests", "test": "tests",
+        "ru": "runners", "runner": "runners",
+        "r": "reporter",
+        "c": "colors", "color": "colors",
+        "f": "files", "file": "files",
+        "w": "workers",
     },
     default: {
         soft: false,
@@ -64,6 +65,7 @@ const cmdLineOptions = minimist(process.argv.slice(2), {
         browser: process.env.browser || process.env.b || "IE",
         timeout: process.env.timeout || 40000,
         tests: process.env.test || process.env.tests || process.env.t,
+        runners: process.env.runners || process.env.runner || process.env.ru,
         light: process.env.light === undefined || process.env.light !== "false",
         reporter: process.env.reporter || process.env.r,
         lint: process.env.lint || true,
@@ -72,7 +74,8 @@ const cmdLineOptions = minimist(process.argv.slice(2), {
     }
 });
 
-function exec(cmd: string, args: string[], complete: () => void = (() => { }), error: (e: any, status: number) => void = (() => { })) {
+const noop = () => {}; // tslint:disable-line no-empty
+function exec(cmd: string, args: string[], complete: () => void = noop, error: (e: any, status: number) => void = noop) {
     console.log(`${cmd} ${args.join(" ")}`);
     // TODO (weswig): Update child_process types to add windowsVerbatimArguments to the type definition
     const subshellFlag = isWin ? "/c" : "-c";
@@ -99,12 +102,12 @@ const lclDirectory = "src/loc/lcl";
 
 const builtDirectory = "built/";
 const builtLocalDirectory = "built/local/";
-const LKGDirectory = "lib/";
+const lkgDirectory = "lib/";
 
 const copyright = "CopyrightNotice.txt";
 
 const compilerFilename = "tsc.js";
-const LKGCompiler = path.join(LKGDirectory, compilerFilename);
+const lkgCompiler = path.join(lkgDirectory, compilerFilename);
 const builtLocalCompiler = path.join(builtLocalDirectory, compilerFilename);
 
 const nodeModulesPathPrefix = path.resolve("./node_modules/.bin/");
@@ -123,34 +126,31 @@ const es2015LibrarySources = [
     "es2015.symbol.wellknown.d.ts"
 ];
 
-const es2015LibrarySourceMap = es2015LibrarySources.map(function(source) {
-    return { target: "lib." + source, sources: ["header.d.ts", source] };
-});
+const es2015LibrarySourceMap = es2015LibrarySources.map(source =>
+    ({ target: "lib." + source, sources: ["header.d.ts", source] }));
 
 const es2016LibrarySource = ["es2016.array.include.d.ts"];
 
-const es2016LibrarySourceMap = es2016LibrarySource.map(function(source) {
-    return { target: "lib." + source, sources: ["header.d.ts", source] };
-});
+const es2016LibrarySourceMap = es2016LibrarySource.map(source =>
+    ({ target: "lib." + source, sources: ["header.d.ts", source] }));
 
 const es2017LibrarySource = [
     "es2017.object.d.ts",
     "es2017.sharedmemory.d.ts",
     "es2017.string.d.ts",
     "es2017.intl.d.ts",
+    "es2017.typedarrays.d.ts",
 ];
 
-const es2017LibrarySourceMap = es2017LibrarySource.map(function(source) {
-    return { target: "lib." + source, sources: ["header.d.ts", source] };
-});
+const es2017LibrarySourceMap = es2017LibrarySource.map(source =>
+    ({ target: "lib." + source, sources: ["header.d.ts", source] }));
 
 const esnextLibrarySource = [
     "esnext.asynciterable.d.ts"
 ];
 
-const esnextLibrarySourceMap = esnextLibrarySource.map(function (source) {
-    return { target: "lib." + source, sources: ["header.d.ts", source] };
-});
+const esnextLibrarySourceMap = esnextLibrarySource.map(source =>
+    ({ target: "lib." + source, sources: ["header.d.ts", source] }));
 
 const hostsLibrarySources = ["dom.generated.d.ts", "webworker.importscripts.d.ts", "scripthost.d.ts"];
 
@@ -171,14 +171,13 @@ const librarySourceMap = [
     // JavaScript + all host library
     { target: "lib.d.ts", sources: ["header.d.ts", "es5.d.ts"].concat(hostsLibrarySources) },
     { target: "lib.es6.d.ts", sources: ["header.d.ts", "es5.d.ts"].concat(es2015LibrarySources, hostsLibrarySources, "dom.iterable.d.ts") },
-    { target: "lib.es2016.full.d.ts", sources: ["header.d.ts", "es2016.d.ts"].concat(es2015LibrarySources, hostsLibrarySources, "dom.iterable.d.ts") },
-    { target: "lib.es2017.full.d.ts", sources: ["header.d.ts", "es2017.d.ts"].concat(es2015LibrarySources, hostsLibrarySources, "dom.iterable.d.ts") },
-    { target: "lib.esnext.full.d.ts", sources: ["header.d.ts", "esnext.d.ts"].concat(es2015LibrarySources, hostsLibrarySources, "dom.iterable.d.ts") },
+    { target: "lib.es2016.full.d.ts", sources: ["header.d.ts", "es2016.d.ts"].concat(hostsLibrarySources, "dom.iterable.d.ts") },
+    { target: "lib.es2017.full.d.ts", sources: ["header.d.ts", "es2017.d.ts"].concat(hostsLibrarySources, "dom.iterable.d.ts") },
+    { target: "lib.esnext.full.d.ts", sources: ["header.d.ts", "esnext.d.ts"].concat(hostsLibrarySources, "dom.iterable.d.ts") },
 ].concat(es2015LibrarySourceMap, es2016LibrarySourceMap, es2017LibrarySourceMap, esnextLibrarySourceMap);
 
-const libraryTargets = librarySourceMap.map(function(f) {
-    return path.join(builtLocalDirectory, f.target);
-});
+const libraryTargets = librarySourceMap.map(f =>
+    path.join(builtLocalDirectory, f.target));
 
 /**
  * .lcg file is what localization team uses to know what messages to localize.
@@ -193,22 +192,19 @@ const generatedLCGFile = path.join(builtLocalDirectory, "enu", "diagnosticMessag
  *    2. 'src\compiler\diagnosticMessages.generated.json' => 'built\local\ENU\diagnosticMessages.generated.json.lcg'
  *       generate the lcg file (source of messages to localize) from the diagnosticMessages.generated.json
  */
-const localizationTargets = ["cs", "de", "es", "fr", "it", "ja", "ko", "pl", "pt-BR", "ru", "tr", "zh-CN", "zh-TW"].map(function (f) {
-    return path.join(builtLocalDirectory, f, "diagnosticMessages.generated.json");
-}).concat(generatedLCGFile);
+const localizationTargets = ["cs", "de", "es", "fr", "it", "ja", "ko", "pl", "pt-BR", "ru", "tr", "zh-CN", "zh-TW"]
+    .map(f => path.join(builtLocalDirectory, f, "diagnosticMessages.generated.json"))
+    .concat(generatedLCGFile);
 
 for (const i in libraryTargets) {
     const entry = librarySourceMap[i];
     const target = libraryTargets[i];
-    const sources = [copyright].concat(entry.sources.map(function(s) {
-        return path.join(libraryDirectory, s);
-    }));
-    gulp.task(target, /*help*/ false, [], function() {
-        return gulp.src(sources)
+    const sources = [copyright].concat(entry.sources.map(s => path.join(libraryDirectory, s)));
+    gulp.task(target, /*help*/ false, [], () =>
+        gulp.src(sources)
             .pipe(newer(target))
             .pipe(concat(target, { newLine: "\n\n" }))
-            .pipe(gulp.dest("."));
-    });
+            .pipe(gulp.dest(".")));
 }
 
 const configureNightlyJs = path.join(scriptsDirectory, "configureNightly.js");
@@ -575,9 +571,7 @@ gulp.task(specMd, /*help*/ false, [word2mdJs], (done) => {
     const specMDFullPath = path.resolve(specMd);
     const cmd = "cscript //nologo " + word2mdJs + " \"" + specWordFullPath + "\" " + "\"" + specMDFullPath + "\"";
     console.log(cmd);
-    cp.exec(cmd, function() {
-        done();
-    });
+    cp.exec(cmd, done);
 });
 
 gulp.task("generate-spec", "Generates a Markdown version of the Language Specification", [specMd]);
@@ -599,7 +593,7 @@ gulp.task("VerifyLKG", /*help*/ false, [], () => {
             ". The following files are missing:\n" + missingFiles.join("\n"));
     }
     // Copy all the targets into the LKG directory
-    return gulp.src([...expectedFiles, path.join(builtLocalDirectory, "**"), `!${path.join(builtLocalDirectory, "tslint")}`, `!${path.join(builtLocalDirectory, "*.*")}`]).pipe(gulp.dest(LKGDirectory));
+    return gulp.src([...expectedFiles, path.join(builtLocalDirectory, "**"), `!${path.join(builtLocalDirectory, "tslint")}`, `!${path.join(builtLocalDirectory, "*.*")}`]).pipe(gulp.dest(lkgDirectory));
 });
 
 gulp.task("LKGInternal", /*help*/ false, ["lib", "local"]);
@@ -658,6 +652,7 @@ function runConsoleTests(defaultReporter: string, runInParallel: boolean, done:
         const debug = cmdLineOptions.debug;
         const inspect = cmdLineOptions.inspect;
         const tests = cmdLineOptions.tests;
+        const runners = cmdLineOptions.runners;
         const light = cmdLineOptions.light;
         const stackTraceLimit = cmdLineOptions.stackTraceLimit;
         const testConfigFile = "test.config";
@@ -678,8 +673,8 @@ function runConsoleTests(defaultReporter: string, runInParallel: boolean, done:
             workerCount = cmdLineOptions.workers;
         }
 
-        if (tests || light || taskConfigsFolder) {
-            writeTestConfigFile(tests, light, taskConfigsFolder, workerCount, stackTraceLimit);
+        if (tests || runners || light || taskConfigsFolder) {
+            writeTestConfigFile(tests, runners, light, taskConfigsFolder, workerCount, stackTraceLimit);
         }
 
         if (tests && tests.toLocaleLowerCase() === "rwc") {
@@ -714,17 +709,13 @@ function runConsoleTests(defaultReporter: string, runInParallel: boolean, done:
             }
             args.push(run);
             setNodeEnvToDevelopment();
-            exec(mocha, args, lintThenFinish, function(e, status) {
-                finish(e, status);
-            });
+            exec(mocha, args, lintThenFinish, finish);
 
         }
         else {
             // run task to load all tests and partition them between workers
             setNodeEnvToDevelopment();
-            exec(host, [run], lintThenFinish, function(e, status) {
-                finish(e, status);
-            });
+            exec(host, [run], lintThenFinish, finish);
         }
     });
 
@@ -874,8 +865,8 @@ function cleanTestDirs(done: (e?: any) => void) {
 }
 
 // used to pass data from jake command line directly to run.js
-function writeTestConfigFile(tests: string, light: boolean, taskConfigsFolder?: string, workerCount?: number, stackTraceLimit?: string) {
-    const testConfigContents = JSON.stringify({ test: tests ? [tests] : undefined, light, workerCount, stackTraceLimit, taskConfigsFolder, noColor: !cmdLineOptions.colors });
+function writeTestConfigFile(tests: string, runners: string, light: boolean, taskConfigsFolder?: string, workerCount?: number, stackTraceLimit?: string) {
+    const testConfigContents = JSON.stringify({ test: tests ? [tests] : undefined, runner: runners ? runners.split(",") : undefined, light, workerCount, stackTraceLimit, taskConfigsFolder, noColor: !cmdLineOptions.colors });
     console.log("Running tests with config: " + testConfigContents);
     fs.writeFileSync("test.config", testConfigContents);
 }
@@ -886,13 +877,14 @@ gulp.task("runtests-browser", "Runs the tests using the built run.js file like '
         if (err) { console.error(err); done(err); process.exit(1); }
         host = "node";
         const tests = cmdLineOptions.tests;
+        const runners = cmdLineOptions.runners;
         const light = cmdLineOptions.light;
         const testConfigFile = "test.config";
         if (fs.existsSync(testConfigFile)) {
             fs.unlinkSync(testConfigFile);
         }
-        if (tests || light) {
-            writeTestConfigFile(tests, light);
+        if (tests || runners || light) {
+            writeTestConfigFile(tests, runners, light);
         }
 
         const args = [nodeServerOutFile];
@@ -1006,7 +998,7 @@ gulp.task(loggedIOJsPath, /*help*/ false, [], (done) => {
     const temp = path.join(builtLocalDirectory, "temp");
     mkdirP(temp, (err) => {
         if (err) { console.error(err); done(err); process.exit(1); }
-        exec(host, [LKGCompiler, "--types", "--target es5", "--lib es5", "--outdir", temp, loggedIOpath], () => {
+        exec(host, [lkgCompiler, "--types", "--target es5", "--lib es5", "--outdir", temp, loggedIOpath], () => {
             fs.renameSync(path.join(temp, "/harness/loggedIO.js"), loggedIOJsPath);
             del(temp).then(() => done(), done);
         }, done);
@@ -1043,7 +1035,7 @@ gulp.task("update-sublime", "Updates the sublime plugin's tsserver", ["local", s
 });
 
 gulp.task("build-rules", "Compiles tslint rules to js", () => {
-    const settings: tsc.Settings = getCompilerSettings({ module: "commonjs", "lib": ["es6"] }, /*useBuiltCompiler*/ false);
+    const settings: tsc.Settings = getCompilerSettings({ module: "commonjs", lib: ["es6"] }, /*useBuiltCompiler*/ false);
     const dest = path.join(builtLocalDirectory, "tslint");
     return gulp.src("scripts/tslint/**/*.ts")
         .pipe(newer({
@@ -1082,7 +1074,7 @@ function sendNextFile(files: {path: string}[], child: cp.ChildProcess, callback:
 function spawnLintWorker(files: {path: string}[], callback: (failures: number) => void) {
     const child = cp.fork("./scripts/parallel-lint");
     let failures = 0;
-    child.on("message", function(data) {
+    child.on("message", data => {
         switch (data.kind) {
             case "result":
                 if (data.failures > 0) {
@@ -1106,7 +1098,7 @@ gulp.task("lint", "Runs tslint on the compiler sources. Optional arguments are:
     const fileMatcher = cmdLineOptions.files;
     const files = fileMatcher
         ? `src/**/${fileMatcher}`
-        : "Gulpfile.ts 'scripts/generateLocalizedDiagnosticMessages.ts' 'scripts/tslint/**/*.ts' 'src/**/*.ts' --exclude src/lib/es5.d.ts --exclude 'src/lib/*.generated.d.ts'";
+        : "Gulpfile.ts 'scripts/generateLocalizedDiagnosticMessages.ts' 'scripts/tslint/**/*.ts' 'src/**/*.ts' --exclude 'src/lib/*.d.ts'";
     const cmd = `node node_modules/tslint/bin/tslint ${files} --formatters-dir ./built/local/tslint/formatters --format autolinkableStylish`;
     console.log("Linting: " + cmd);
     child_process.execSync(cmd, { stdio: [0, 1, 2] });
diff --git a/Jakefile.js b/Jakefile.js
index da7d96f0699..c2d0717641f 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -105,6 +105,7 @@ var harnessCoreSources = [
     "projectsRunner.ts",
     "loggedIO.ts",
     "rwcRunner.ts",
+    "externalCompileRunner.ts",
     "test262Runner.ts",
     "./parallel/shared.ts",
     "./parallel/host.ts",
@@ -196,7 +197,8 @@ var es2017LibrarySource = [
     "es2017.object.d.ts",
     "es2017.sharedmemory.d.ts",
     "es2017.string.d.ts",
-    "es2017.intl.d.ts"
+    "es2017.intl.d.ts",
+    "es2017.typedarrays.d.ts",
 ];
 
 var es2017LibrarySourceMap = es2017LibrarySource.map(function (source) {
@@ -843,8 +845,9 @@ function cleanTestDirs() {
 }
 
 // used to pass data from jake command line directly to run.js
-function writeTestConfigFile(tests, light, taskConfigsFolder, workerCount, stackTraceLimit, colors) {
+function writeTestConfigFile(tests, runners, light, taskConfigsFolder, workerCount, stackTraceLimit, colors) {
     var testConfigContents = JSON.stringify({
+        runners: runners ? runners.split(",") : undefined,
         test: tests ? [tests] : undefined,
         light: light,
         workerCount: workerCount,
@@ -870,6 +873,7 @@ function runConsoleTests(defaultReporter, runInParallel) {
     var debug = process.env.debug || process.env["debug-brk"] || process.env.d;
     var inspect = process.env.inspect || process.env["inspect-brk"] || process.env.i;
     var testTimeout = process.env.timeout || defaultTestTimeout;
+    var runners = process.env.runners || process.env.runner || process.env.ru;
     var tests = process.env.test || process.env.tests || process.env.t;
     var light = process.env.light === undefined || process.env.light !== "false";
     var stackTraceLimit = process.env.stackTraceLimit;
@@ -891,8 +895,8 @@ function runConsoleTests(defaultReporter, runInParallel) {
         workerCount = process.env.workerCount || process.env.p || os.cpus().length;
     }
 
-    if (tests || light || taskConfigsFolder) {
-        writeTestConfigFile(tests, light, taskConfigsFolder, workerCount, stackTraceLimit, colors);
+    if (tests || runners || light || taskConfigsFolder) {
+        writeTestConfigFile(tests, runners, light, taskConfigsFolder, workerCount, stackTraceLimit, colors);
     }
 
     if (tests && tests.toLocaleLowerCase() === "rwc") {
@@ -1027,14 +1031,15 @@ task("runtests-browser", ["browserify", nodeServerOutFile], function () {
     cleanTestDirs();
     host = "node";
     var browser = process.env.browser || process.env.b ||  (os.platform() === "linux" ? "chrome" : "IE");
+    var runners = process.env.runners || process.env.runner || process.env.ru;
     var tests = process.env.test || process.env.tests || process.env.t;
     var light = process.env.light || false;
     var testConfigFile = 'test.config';
     if (fs.existsSync(testConfigFile)) {
         fs.unlinkSync(testConfigFile);
     }
-    if (tests || light) {
-        writeTestConfigFile(tests, light);
+    if (tests || runners || light) {
+        writeTestConfigFile(tests, runners, light);
     }
 
     tests = tests ? tests : '';
@@ -1282,7 +1287,7 @@ task("lint", ["build-rules"], () => {
     const fileMatcher = process.env.f || process.env.file || process.env.files;
     const files = fileMatcher
         ? `src/**/${fileMatcher}`
-        : "Gulpfile.ts 'scripts/generateLocalizedDiagnosticMessages.ts' 'scripts/tslint/**/*.ts' 'src/**/*.ts' --exclude src/lib/es5.d.ts --exclude 'src/lib/*.generated.d.ts'";
+        : "Gulpfile.ts 'scripts/generateLocalizedDiagnosticMessages.ts' 'scripts/tslint/**/*.ts' 'src/**/*.ts' --exclude 'src/lib/*.d.ts'";
     const cmd = `node node_modules/tslint/bin/tslint ${files} --formatters-dir ./built/local/tslint/formatters --format autolinkableStylish`;
     console.log("Linting: " + cmd);
     jake.exec([cmd], { interactive: true }, () => {
diff --git a/netci.groovy b/netci.groovy
index fc6d00e4e7f..5fa8b02baf2 100644
--- a/netci.groovy
+++ b/netci.groovy
@@ -5,7 +5,7 @@ import jobs.generation.Utilities;
 def project = GithubProject
 def branch = GithubBranchName
 
-def nodeVersions = ['stable', '6', '4']
+def nodeVersions = ['stable', '8', '6']
 
 nodeVersions.each { nodeVer ->
 
diff --git a/package.json b/package.json
index e76d480937c..e329db05d85 100644
--- a/package.json
+++ b/package.json
@@ -74,10 +74,12 @@
         "q": "latest",
         "run-sequence": "latest",
         "sorcery": "latest",
+        "source-map-support": "latest",
         "through2": "latest",
         "travis-fold": "latest",
         "ts-node": "latest",
         "tslint": "latest",
+        "vinyl": "latest",
         "colors": "latest",
         "typescript": "next"
     },
diff --git a/scripts/generateLocalizedDiagnosticMessages.ts b/scripts/generateLocalizedDiagnosticMessages.ts
index 36df92590c7..566eb557fd5 100644
--- a/scripts/generateLocalizedDiagnosticMessages.ts
+++ b/scripts/generateLocalizedDiagnosticMessages.ts
@@ -65,10 +65,11 @@ function main(): void {
      * There are three exceptions, zh-CN, zh-TW and pt-BR.
      */
     function getPreferedLocaleName(localeName: string) {
+        localeName = localeName.toLowerCase();
         switch (localeName) {
-            case "zh-CN":
-            case "zh-TW":
-            case "pt-BR":
+            case "zh-cn":
+            case "zh-tw":
+            case "pt-br":
                 return localeName;
             default:
                 return localeName.split("-")[0];
@@ -86,9 +87,9 @@ function main(): void {
         const out: any = {};
         for (const item of o.LCX.Item[0].Item[0].Item) {
             let ItemId = item.$.ItemId;
-            let Val = item.Str[0].Tgt ? item.Str[0].Tgt[0].Val[0] : item.Str[0].Val[0];
+            let val = item.Str[0].Tgt ? item.Str[0].Tgt[0].Val[0] : item.Str[0].Val[0];
 
-            if (typeof ItemId !== "string" || typeof Val !== "string") {
+            if (typeof ItemId !== "string" || typeof val !== "string") {
                 console.error("Unexpected XML file structure");
                 process.exit(1);
             }
@@ -97,8 +98,8 @@ function main(): void {
                 ItemId = ItemId.slice(1); // remove leading semicolon
             }
 
-            Val = Val.replace(/]5D;/, "]"); // unescape `]`
-            out[ItemId] = Val;
+            val = val.replace(/]5D;/, "]"); // unescape `]`
+            out[ItemId] = val;
         }
         return JSON.stringify(out, undefined, 2);
     }
diff --git a/scripts/ior.ts b/scripts/ior.ts
index 91580203350..374747d8439 100644
--- a/scripts/ior.ts
+++ b/scripts/ior.ts
@@ -64,7 +64,6 @@ module Commands {
             }
             if (path.charAt(1) === ":") {
                 if (path.charAt(2) === directorySeparator) return 3;
-                return 2;
             }
             return 0;
         }
diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index ff4047d310d..dd66564b134 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -1,4 +1,5 @@
 /// <reference path="../src/compiler/sys.ts" />
+/// <reference path="../src/compiler/core.ts" />
 
 interface DiagnosticDetails {
     category: string;
@@ -9,80 +10,79 @@ interface DiagnosticDetails {
 type InputDiagnosticMessageTable = ts.Map<DiagnosticDetails>;
 
 function main(): void {
-    var sys = ts.sys;
+    const sys = ts.sys;
     if (sys.args.length < 1) {
-        sys.write("Usage:" + sys.newLine)
+        sys.write("Usage:" + sys.newLine);
         sys.write("\tnode processDiagnosticMessages.js <diagnostic-json-input-file>" + sys.newLine);
         return;
     }
 
     function writeFile(fileName: string, contents: string) {
-        // TODO: Fix path joining
-        var inputDirectory = inputFilePath.substr(0,inputFilePath.lastIndexOf("/"));
-        var fileOutputPath = inputDirectory + "/" + fileName;
+        const inputDirectory = ts.getDirectoryPath(inputFilePath);
+        const fileOutputPath = ts.combinePaths(inputDirectory, fileName);
         sys.writeFile(fileOutputPath, contents);
     }
 
-    var inputFilePath = sys.args[0].replace(/\\/g, "/");
-    var inputStr = sys.readFile(inputFilePath);
+    const inputFilePath = sys.args[0].replace(/\\/g, "/");
+    const inputStr = sys.readFile(inputFilePath);
 
-    var diagnosticMessagesJson: { [key: string]: DiagnosticDetails } = JSON.parse(inputStr);
-    // Check that there are no duplicates.
-    const seenNames = ts.createMap<true>();
-    for (const name of Object.keys(diagnosticMessagesJson)) {
-        if (seenNames.has(name))
-            throw new Error(`Name ${name} appears twice`);
-        seenNames.set(name, true);
-    }
+    const diagnosticMessagesJson: { [key: string]: DiagnosticDetails } = JSON.parse(inputStr);
 
     const diagnosticMessages: InputDiagnosticMessageTable = ts.createMapFromTemplate(diagnosticMessagesJson);
 
-    var infoFileOutput = buildInfoFileOutput(diagnosticMessages);
+    const outputFilesDir = ts.getDirectoryPath(inputFilePath);
+    const thisFilePathRel = ts.getRelativePathToDirectoryOrUrl(outputFilesDir, sys.getExecutingFilePath(),
+        sys.getCurrentDirectory(), ts.createGetCanonicalFileName(sys.useCaseSensitiveFileNames), /* isAbsolutePathAnUrl */ false);
+
+    const infoFileOutput = buildInfoFileOutput(diagnosticMessages, "./diagnosticInformationMap.generated.ts", thisFilePathRel);
     checkForUniqueCodes(diagnosticMessages);
     writeFile("diagnosticInformationMap.generated.ts", infoFileOutput);
 
-    var messageOutput = buildDiagnosticMessageOutput(diagnosticMessages);
+    const messageOutput = buildDiagnosticMessageOutput(diagnosticMessages);
     writeFile("diagnosticMessages.generated.json", messageOutput);
 }
 
 function checkForUniqueCodes(diagnosticTable: InputDiagnosticMessageTable) {
     const allCodes: { [key: number]: true | undefined } = [];
     diagnosticTable.forEach(({ code }) => {
-        if (allCodes[code])
+        if (allCodes[code]) {
             throw new Error(`Diagnostic code ${code} appears more than once.`);
+        }
         allCodes[code] = true;
     });
 }
 
-function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable): string {
-    var result =
-        '// <auto-generated />\r\n' +
-        '/// <reference path="types.ts" />\r\n' +
-        '/* @internal */\r\n' +
-        'namespace ts {\r\n' +
+function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, inputFilePathRel: string, thisFilePathRel: string): string {
+    let result =
+        "// <auto-generated />\r\n" +
+        "// generated from '" + inputFilePathRel + "' by '" + thisFilePathRel + "'\r\n" +
+        "/// <reference path=\"types.ts\" />\r\n" +
+        "/* @internal */\r\n" +
+        "namespace ts {\r\n" +
         "    function diag(code: number, category: DiagnosticCategory, key: string, message: string): DiagnosticMessage {\r\n" +
         "        return { code, category, key, message };\r\n" +
         "    }\r\n" +
-        '    export const Diagnostics = {\r\n';
+        "    // tslint:disable-next-line variable-name\r\n" +
+        "    export const Diagnostics = {\r\n";
     messageTable.forEach(({ code, category }, name) => {
         const propName = convertPropertyName(name);
         result += `        ${propName}: diag(${code}, DiagnosticCategory.${category}, "${createKey(propName, code)}", ${JSON.stringify(name)}),\r\n`;
     });
 
-    result += '    };\r\n}';
+    result += "    };\r\n}";
 
     return result;
 }
 
 function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable): string {
-    let result = '{';
+    let result = "{";
     messageTable.forEach(({ code }, name) => {
         const propName = convertPropertyName(name);
         result += `\r\n  "${createKey(propName, code)}" : "${name.replace(/[\"]/g, '\\"')}",`;
     });
 
     // Shave trailing comma, then add newline and ending brace
-    result = result.slice(0, result.length - 1) + '\r\n}';
+    result = result.slice(0, result.length - 1) + "\r\n}";
 
     // Assert that we generated valid JSON
     JSON.parse(result);
@@ -90,15 +90,15 @@ function buildDiagnosticMessageOutput(messageTable: InputDiagnosticMessageTable)
     return result;
 }
 
-function createKey(name: string, code: number) : string {
-    return name.slice(0, 100) + '_' + code;
+function createKey(name: string, code: number): string {
+    return name.slice(0, 100) + "_" + code;
 }
 
 function convertPropertyName(origName: string): string {
-    var result = origName.split("").map(char => {
-        if (char === '*') { return "_Asterisk"; }
-        if (char === '/') { return "_Slash"; }
-        if (char === ':') { return "_Colon"; }
+    let result = origName.split("").map(char => {
+        if (char === "*") { return "_Asterisk"; }
+        if (char === "/") { return "_Slash"; }
+        if (char === ":") { return "_Colon"; }
         return /\w/.test(char) ? char : "_";
     }).join("");
 
@@ -106,7 +106,7 @@ function convertPropertyName(origName: string): string {
     result = result.replace(/_+/g, "_");
 
     // remove any leading underscore, unless it is followed by a number.
-    result = result.replace(/^_([^\d])/, "$1")
+    result = result.replace(/^_([^\d])/, "$1");
 
     // get rid of all trailing underscores.
     result = result.replace(/_$/, "");
diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 35a62a644d8..4e89abde780 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -133,7 +133,7 @@ namespace ts {
 
         let symbolCount = 0;
 
-        let Symbol: { new (flags: SymbolFlags, name: __String): Symbol };
+        let Symbol: { new (flags: SymbolFlags, name: __String): Symbol }; // tslint:disable-line variable-name
         let classifiableNames: UnderscoreEscapedMap<true>;
 
         const unreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
@@ -192,7 +192,7 @@ namespace ts {
         return bindSourceFile;
 
         function bindInStrictMode(file: SourceFile, opts: CompilerOptions): boolean {
-            if ((opts.alwaysStrict === undefined ? opts.strict : opts.alwaysStrict) && !file.isDeclarationFile) {
+            if (getStrictOptionValue(opts, "alwaysStrict") && !file.isDeclarationFile) {
                 // bind in strict mode source files with alwaysStrict option
                 return true;
             }
@@ -1550,7 +1550,7 @@ namespace ts {
         function setExportContextFlag(node: ModuleDeclaration | SourceFile) {
             // A declaration source file or ambient module declaration that contains no export declarations (but possibly regular
             // declarations with export modifiers) is an export context in which declarations are implicitly exported.
-            if (isInAmbientContext(node) && !hasExportDeclarations(node)) {
+            if (node.flags & NodeFlags.Ambient && !hasExportDeclarations(node)) {
                 node.flags |= NodeFlags.ExportContext;
             }
             else {
@@ -1726,7 +1726,7 @@ namespace ts {
                 node.originalKeywordKind >= SyntaxKind.FirstFutureReservedWord &&
                 node.originalKeywordKind <= SyntaxKind.LastFutureReservedWord &&
                 !isIdentifierName(node) &&
-                !isInAmbientContext(node)) {
+                !(node.flags & NodeFlags.Ambient)) {
 
                 // Report error only if there are no parse errors in file
                 if (!file.parseDiagnostics.length) {
@@ -2205,15 +2205,14 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Alias, getDeclarationName(node));
             }
             else {
-                // An export default clause with an expression exports a value
-                // We want to exclude both class and function here,  this is necessary to issue an error when there are both
-                // default export-assignment and default export function and class declaration.
-                const flags = node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(<ExportAssignment>node)
+                const flags = node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(node)
                     // An export default clause with an EntityNameExpression exports all meanings of that identifier
                     ? SymbolFlags.Alias
                     // An export default clause with any other expression exports a value
                     : SymbolFlags.Property;
-                declareSymbol(container.symbol.exports, container.symbol, node, flags, SymbolFlags.Property | SymbolFlags.AliasExcludes | SymbolFlags.Class | SymbolFlags.Function);
+                // If there is an `export default x;` alias declaration, can't `export default` anything else.
+                // (In contrast, you can still have `export default function f() {}` and `export default interface I {}`.)
+                declareSymbol(container.symbol.exports, container.symbol, node, flags, SymbolFlags.All);
             }
         }
 
@@ -2481,7 +2480,7 @@ namespace ts {
         }
 
         function bindParameter(node: ParameterDeclaration) {
-            if (inStrictMode && !isInAmbientContext(node)) {
+            if (inStrictMode && !(node.flags & NodeFlags.Ambient)) {
                 // It is a SyntaxError if the identifier eval or arguments appears within a FormalParameterList of a
                 // strict mode FunctionLikeDeclaration or FunctionExpression(13.1)
                 checkStrictModeEvalOrArguments(node, node.name);
@@ -2503,7 +2502,7 @@ namespace ts {
         }
 
         function bindFunctionDeclaration(node: FunctionDeclaration) {
-            if (!file.isDeclarationFile && !isInAmbientContext(node)) {
+            if (!file.isDeclarationFile && !(node.flags & NodeFlags.Ambient)) {
                 if (isAsyncFunction(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }
@@ -2520,7 +2519,7 @@ namespace ts {
         }
 
         function bindFunctionExpression(node: FunctionExpression) {
-            if (!file.isDeclarationFile && !isInAmbientContext(node)) {
+            if (!file.isDeclarationFile && !(node.flags & NodeFlags.Ambient)) {
                 if (isAsyncFunction(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }
@@ -2534,7 +2533,7 @@ namespace ts {
         }
 
         function bindPropertyOrMethodOrAccessor(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags) {
-            if (!file.isDeclarationFile && !isInAmbientContext(node) && isAsyncFunction(node)) {
+            if (!file.isDeclarationFile && !(node.flags & NodeFlags.Ambient) && isAsyncFunction(node)) {
                 emitFlags |= NodeFlags.HasAsyncFunctions;
             }
 
@@ -2583,7 +2582,7 @@ namespace ts {
                     //   On the other side we do want to report errors on non-initialized 'lets' because of TDZ
                     const reportUnreachableCode =
                         !options.allowUnreachableCode &&
-                        !isInAmbientContext(node) &&
+                        !(node.flags & NodeFlags.Ambient) &&
                         (
                             node.kind !== SyntaxKind.VariableStatement ||
                             getCombinedNodeFlags((<VariableStatement>node).declarationList) & NodeFlags.BlockScoped ||
@@ -2963,6 +2962,7 @@ namespace ts {
             || hasModifier(node, ModifierFlags.TypeScriptModifier)
             || node.typeParameters
             || node.type
+            || (node.name && isComputedPropertyName(node.name)) // While computed method names aren't typescript, the TS transform must visit them to emit property declarations correctly
             || !node.body) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
@@ -2993,6 +2993,7 @@ namespace ts {
         if (node.decorators
             || hasModifier(node, ModifierFlags.TypeScriptModifier)
             || node.type
+            || (node.name && isComputedPropertyName(node.name)) // While computed accessor names aren't typescript, the TS transform must visit them to emit property declarations correctly
             || !node.body) {
             transformFlags |= TransformFlags.AssertTypeScript;
         }
@@ -3296,6 +3297,9 @@ namespace ts {
             case SyntaxKind.JsxOpeningElement:
             case SyntaxKind.JsxText:
             case SyntaxKind.JsxClosingElement:
+            case SyntaxKind.JsxFragment:
+            case SyntaxKind.JsxOpeningFragment:
+            case SyntaxKind.JsxClosingFragment:
             case SyntaxKind.JsxAttribute:
             case SyntaxKind.JsxAttributes:
             case SyntaxKind.JsxSpreadAttribute:
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index aaaa0ed50b8..a9aaa77fa74 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -48,9 +48,11 @@ namespace ts {
         let requestedExternalEmitHelpers: ExternalEmitHelpers;
         let externalHelpersModule: Symbol;
 
+        // tslint:disable variable-name
         const Symbol = objectAllocator.getSymbolConstructor();
         const Type = objectAllocator.getTypeConstructor();
         const Signature = objectAllocator.getSignatureConstructor();
+        // tslint:enable variable-name
 
         let typeCount = 0;
         let symbolCount = 0;
@@ -64,11 +66,11 @@ namespace ts {
         const languageVersion = getEmitScriptTarget(compilerOptions);
         const modulekind = getEmitModuleKind(compilerOptions);
         const noUnusedIdentifiers = !!compilerOptions.noUnusedLocals || !!compilerOptions.noUnusedParameters;
-        const allowSyntheticDefaultImports = typeof compilerOptions.allowSyntheticDefaultImports !== "undefined" ? compilerOptions.allowSyntheticDefaultImports : modulekind === ModuleKind.System;
-        const strictNullChecks = compilerOptions.strictNullChecks === undefined ? compilerOptions.strict : compilerOptions.strictNullChecks;
-        const strictFunctionTypes = compilerOptions.strictFunctionTypes === undefined ? compilerOptions.strict : compilerOptions.strictFunctionTypes;
-        const noImplicitAny = compilerOptions.noImplicitAny === undefined ? compilerOptions.strict : compilerOptions.noImplicitAny;
-        const noImplicitThis = compilerOptions.noImplicitThis === undefined ? compilerOptions.strict : compilerOptions.noImplicitThis;
+        const allowSyntheticDefaultImports = getAllowSyntheticDefaultImports(compilerOptions);
+        const strictNullChecks = getStrictOptionValue(compilerOptions, "strictNullChecks");
+        const strictFunctionTypes = getStrictOptionValue(compilerOptions, "strictFunctionTypes");
+        const noImplicitAny = getStrictOptionValue(compilerOptions, "noImplicitAny");
+        const noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis");
 
         const emitResolver = createResolver();
         const nodeBuilder = createNodeBuilder();
@@ -260,6 +262,7 @@ namespace ts {
         const literalTypes = createMap<LiteralType>();
         const indexedAccessTypes = createMap<IndexedAccessType>();
         const evolvingArrayTypes: EvolvingArrayType[] = [];
+        const undefinedProperties = createMap<Symbol>() as UnderscoreEscapedMap<Symbol>;
 
         const unknownSymbol = createSymbol(SymbolFlags.Property, "unknown" as __String);
         const resolvingSymbol = createSymbol(0, InternalSymbolName.Resolving);
@@ -280,6 +283,7 @@ namespace ts {
         const voidType = createIntrinsicType(TypeFlags.Void, "void");
         const neverType = createIntrinsicType(TypeFlags.Never, "never");
         const silentNeverType = createIntrinsicType(TypeFlags.Never, "never");
+        const implicitNeverType = createIntrinsicType(TypeFlags.Never, "never");
         const nonPrimitiveType = createIntrinsicType(TypeFlags.NonPrimitive, "object");
 
         const emptyObjectType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
@@ -451,29 +455,29 @@ namespace ts {
         }
 
         const typeofEQFacts = createMapFromTemplate({
-            "string": TypeFacts.TypeofEQString,
-            "number": TypeFacts.TypeofEQNumber,
-            "boolean": TypeFacts.TypeofEQBoolean,
-            "symbol": TypeFacts.TypeofEQSymbol,
-            "undefined": TypeFacts.EQUndefined,
-            "object": TypeFacts.TypeofEQObject,
-            "function": TypeFacts.TypeofEQFunction
+            string: TypeFacts.TypeofEQString,
+            number: TypeFacts.TypeofEQNumber,
+            boolean: TypeFacts.TypeofEQBoolean,
+            symbol: TypeFacts.TypeofEQSymbol,
+            undefined: TypeFacts.EQUndefined,
+            object: TypeFacts.TypeofEQObject,
+            function: TypeFacts.TypeofEQFunction
         });
         const typeofNEFacts = createMapFromTemplate({
-            "string": TypeFacts.TypeofNEString,
-            "number": TypeFacts.TypeofNENumber,
-            "boolean": TypeFacts.TypeofNEBoolean,
-            "symbol": TypeFacts.TypeofNESymbol,
-            "undefined": TypeFacts.NEUndefined,
-            "object": TypeFacts.TypeofNEObject,
-            "function": TypeFacts.TypeofNEFunction
+            string: TypeFacts.TypeofNEString,
+            number: TypeFacts.TypeofNENumber,
+            boolean: TypeFacts.TypeofNEBoolean,
+            symbol: TypeFacts.TypeofNESymbol,
+            undefined: TypeFacts.NEUndefined,
+            object: TypeFacts.TypeofNEObject,
+            function: TypeFacts.TypeofNEFunction
         });
         const typeofTypesByName = createMapFromTemplate<Type>({
-            "string": stringType,
-            "number": numberType,
-            "boolean": booleanType,
-            "symbol": esSymbolType,
-            "undefined": undefinedType
+            string: stringType,
+            number: numberType,
+            boolean: booleanType,
+            symbol: esSymbolType,
+            undefined: undefinedType
         });
         const typeofType = createTypeofType();
 
@@ -487,17 +491,6 @@ namespace ts {
         /** Things we lazy load from the JSX namespace */
         const jsxTypes = createUnderscoreEscapedMap<Type>();
 
-        const JsxNames = {
-            JSX: "JSX" as __String,
-            IntrinsicElements: "IntrinsicElements" as __String,
-            ElementClass: "ElementClass" as __String,
-            ElementAttributesPropertyNameContainer: "ElementAttributesProperty" as __String,
-            ElementChildrenAttributeNameContainer: "ElementChildrenAttribute" as __String,
-            Element: "Element" as __String,
-            IntrinsicAttributes: "IntrinsicAttributes" as __String,
-            IntrinsicClassAttributes: "IntrinsicClassAttributes" as __String
-        };
-
         const subtypeRelation = createMap<RelationComparisonResult>();
         const assignableRelation = createMap<RelationComparisonResult>();
         const comparableRelation = createMap<RelationComparisonResult>();
@@ -528,6 +521,11 @@ namespace ts {
             Strict,
         }
 
+        const enum MappedTypeModifiers {
+            Readonly = 1 << 0,
+            Optional = 1 << 1,
+        }
+
         const builtinGlobals = createSymbolTable();
         builtinGlobals.set(undefinedSymbol.escapedName, undefinedSymbol);
 
@@ -690,7 +688,7 @@ namespace ts {
             else {
                 // find a module that about to be augmented
                 // do not validate names of augmentations that are defined in ambient context
-                const moduleNotFoundError = !isInAmbientContext(moduleName.parent.parent)
+                const moduleNotFoundError = !(moduleName.parent.parent.flags & NodeFlags.Ambient)
                     ? Diagnostics.Invalid_module_name_in_augmentation_module_0_cannot_be_found
                     : undefined;
                 let mainModule = resolveExternalModuleNameWorker(moduleName, moduleName, moduleNotFoundError, /*isForAugmentation*/ true);
@@ -795,7 +793,7 @@ namespace ts {
                 if ((modulekind && (declarationFile.externalModuleIndicator || useFile.externalModuleIndicator)) ||
                     (!compilerOptions.outFile && !compilerOptions.out) ||
                     isInTypeQuery(usage) ||
-                    isInAmbientContext(declaration)) {
+                    declaration.flags & NodeFlags.Ambient) {
                     // nodes are in different files and order cannot be determined
                     return true;
                 }
@@ -1367,7 +1365,7 @@ namespace ts {
                 }
             }
             else if (meaning & (SymbolFlags.Type & ~SymbolFlags.NamespaceModule & ~SymbolFlags.Value)) {
-                const symbol = resolveSymbol(resolveName(errorLocation, name, SymbolFlags.NamespaceModule & ~SymbolFlags.Type, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
+                const symbol = resolveSymbol(resolveName(errorLocation, name, (SymbolFlags.ValueModule | SymbolFlags.NamespaceModule) & ~SymbolFlags.Type, /*nameNotFoundMessage*/undefined, /*nameArg*/ undefined, /*isUse*/ false));
                 if (symbol) {
                     error(errorLocation, Diagnostics.Cannot_use_namespace_0_as_a_type, unescapeLeadingUnderscores(name));
                     return true;
@@ -1383,7 +1381,7 @@ namespace ts {
 
             Debug.assert(declaration !== undefined, "Declaration to checkResolvedBlockScopedVariable is undefined");
 
-            if (!isInAmbientContext(declaration) && !isBlockScopedNameDeclaredBeforeUse(declaration, errorLocation)) {
+            if (!(declaration.flags & NodeFlags.Ambient) && !isBlockScopedNameDeclaredBeforeUse(declaration, errorLocation)) {
                 if (result.flags & SymbolFlags.BlockScopedVariable) {
                     error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationNameToString(getNameOfDeclaration(declaration)));
                 }
@@ -1906,8 +1904,9 @@ namespace ts {
          * Extends one symbol table with another while collecting information on name collisions for error message generation into the `lookupTable` argument
          * Not passing `lookupTable` and `exportNode` disables this collection, and just extends the tables
          */
-        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: ExportCollisionTrackerTable, exportNode?: ExportDeclaration) {
-            source && source.forEach((sourceSymbol, id) => {
+        function extendExportSymbols(target: SymbolTable, source: SymbolTable | undefined, lookupTable?: ExportCollisionTrackerTable, exportNode?: ExportDeclaration) {
+            if (!source) return;
+            source.forEach((sourceSymbol, id) => {
                 if (id === "default") return;
 
                 const targetSymbol = target.get(id);
@@ -2162,7 +2161,6 @@ namespace ts {
                 return forEachEntry(symbols, symbolFromSymbolTable => {
                     if (symbolFromSymbolTable.flags & SymbolFlags.Alias
                         && symbolFromSymbolTable.escapedName !== "export="
-                        && !getDeclarationOfKind(symbolFromSymbolTable, SyntaxKind.ExportSpecifier)
                         && !(isUMDExportSymbol(symbolFromSymbolTable) && enclosingDeclaration && isExternalModule(getSourceFileOfNode(enclosingDeclaration)))
                         // If `!useOnlyExternalAliasing`, we can use any type of alias to get the name
                         && (!useOnlyExternalAliasing || some(symbolFromSymbolTable.declarations, isExternalModuleImportEqualsDeclaration))) {
@@ -2443,18 +2441,21 @@ namespace ts {
         function createNodeBuilder() {
             return {
                 typeToTypeNode: (type: Type, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => {
+                    Debug.assert(enclosingDeclaration === undefined || (enclosingDeclaration.flags & NodeFlags.Synthesized) === 0);
                     const context = createNodeBuilderContext(enclosingDeclaration, flags);
                     const resultingNode = typeToTypeNodeHelper(type, context);
                     const result = context.encounteredError ? undefined : resultingNode;
                     return result;
                 },
                 indexInfoToIndexSignatureDeclaration: (indexInfo: IndexInfo, kind: IndexKind, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => {
+                    Debug.assert(enclosingDeclaration === undefined || (enclosingDeclaration.flags & NodeFlags.Synthesized) === 0);
                     const context = createNodeBuilderContext(enclosingDeclaration, flags);
                     const resultingNode = indexInfoToIndexSignatureDeclarationHelper(indexInfo, kind, context);
                     const result = context.encounteredError ? undefined : resultingNode;
                     return result;
                 },
                 signatureToSignatureDeclaration: (signature: Signature, kind: SyntaxKind, enclosingDeclaration?: Node, flags?: NodeBuilderFlags) => {
+                    Debug.assert(enclosingDeclaration === undefined || (enclosingDeclaration.flags & NodeFlags.Synthesized) === 0);
                     const context = createNodeBuilderContext(enclosingDeclaration, flags);
                     const resultingNode = signatureToSignatureDeclarationHelper(signature, kind, context);
                     const result = context.encounteredError ? undefined : resultingNode;
@@ -2495,7 +2496,7 @@ namespace ts {
                 if (type.flags & TypeFlags.EnumLiteral && !(type.flags & TypeFlags.Union)) {
                     const parentSymbol = getParentOfSymbol(type.symbol);
                     const parentName = symbolToName(parentSymbol, context, SymbolFlags.Type, /*expectsIdentifier*/ false);
-                    const enumLiteralName = getDeclaredTypeOfSymbol(parentSymbol) === type ? parentName : createQualifiedName(parentName, getNameOfSymbol(type.symbol, context));
+                    const enumLiteralName = getDeclaredTypeOfSymbol(parentSymbol) === type ? parentName : createQualifiedName(parentName, symbolName(type.symbol));
                     return createTypeReferenceNode(enumLiteralName, /*typeArguments*/ undefined);
                 }
                 if (type.flags & TypeFlags.EnumLike) {
@@ -2850,8 +2851,7 @@ namespace ts {
             function mapToTypeNodes(types: Type[], context: NodeBuilderContext): TypeNode[] {
                 if (some(types)) {
                     const result = [];
-                    for (let i = 0; i < types.length; ++i) {
-                        const type = types[i];
+                    for (const type of types) {
                         const typeNode = typeToTypeNodeHelper(type, context);
                         if (typeNode) {
                             result.push(typeNode);
@@ -3015,8 +3015,7 @@ namespace ts {
                         typeParameterNodes = mapToTypeNodes(typeParameters, context);
                     }
 
-                    const symbolName = getNameOfSymbol(symbol, context);
-                    const identifier = setEmitFlags(createIdentifier(symbolName, typeParameterNodes), EmitFlags.NoAsciiEscaping);
+                    const identifier = setEmitFlags(createIdentifier(getNameOfSymbolAsWritten(symbol, context), typeParameterNodes), EmitFlags.NoAsciiEscaping);
 
                     return index > 0 ? createQualifiedName(createEntityNameFromSymbolChain(chain, index - 1), identifier) : identifier;
                 }
@@ -3128,7 +3127,14 @@ namespace ts {
             symbolStack: Symbol[] | undefined;
         }
 
-        function getNameOfSymbol(symbol: Symbol, context?: NodeBuilderContext): string {
+        /**
+         * Gets a human-readable name for a symbol.
+         * Should *not* be used for the right-hand side of a `.` -- use `symbolName(symbol)` for that instead.
+         *
+         * Unlike `symbolName(symbol)`, this will include quotes if the name is from a string literal.
+         * It will also use a representation of a number as written instead of a decimal form, e.g. `0o11` instead of `9`.
+         */
+        function getNameOfSymbolAsWritten(symbol: Symbol, context?: NodeBuilderContext): string {
             if (symbol.declarations && symbol.declarations.length) {
                 const declaration = symbol.declarations[0];
                 const name = getNameOfDeclaration(declaration);
@@ -3165,7 +3171,7 @@ namespace ts {
              * for the name of the symbol if it is available to match how the user wrote the name.
              */
             function appendSymbolNameOnly(symbol: Symbol, writer: SymbolWriter): void {
-                writer.writeSymbol(getNameOfSymbol(symbol), symbol);
+                writer.writeSymbol(getNameOfSymbolAsWritten(symbol), symbol);
             }
 
             /**
@@ -3174,7 +3180,7 @@ namespace ts {
              * ensuring that any names written with literals use element accesses.
              */
             function appendPropertyOrElementAccessForSymbol(symbol: Symbol, writer: SymbolWriter): void {
-                const symbolName = getNameOfSymbol(symbol);
+                const symbolName = symbol.escapedName === "default" ? "default" : getNameOfSymbolAsWritten(symbol);
                 const firstChar = symbolName.charCodeAt(0);
                 const needsElementAccess = !isIdentifierStart(firstChar, languageVersion);
 
@@ -3939,7 +3945,7 @@ namespace ts {
                         const parent = getDeclarationContainer(node);
                         // If the node is not exported or it is not ambient module element (except import declaration)
                         if (!(getCombinedModifierFlags(node) & ModifierFlags.Export) &&
-                            !(node.kind !== SyntaxKind.ImportEqualsDeclaration && parent.kind !== SyntaxKind.SourceFile && isInAmbientContext(parent))) {
+                            !(node.kind !== SyntaxKind.ImportEqualsDeclaration && parent.kind !== SyntaxKind.SourceFile && parent.flags & NodeFlags.Ambient)) {
                             return isGlobalSourceFile(parent);
                         }
                         // Exported members/ambient module elements (exception import declaration) are visible if parent is visible
@@ -4317,7 +4323,7 @@ namespace ts {
 
             if ((noImplicitAny || isInJavaScriptFile(declaration)) &&
                 declaration.kind === SyntaxKind.VariableDeclaration && !isBindingPattern(declaration.name) &&
-                !(getCombinedModifierFlags(declaration) & ModifierFlags.Export) && !isInAmbientContext(declaration)) {
+                !(getCombinedModifierFlags(declaration) & ModifierFlags.Export) && !(declaration.flags & NodeFlags.Ambient)) {
                 // If --noImplicitAny is on or the declaration is in a Javascript file,
                 // use control flow tracked 'any' type for non-ambient, non-exported var or let variables with no
                 // initializer or a 'null' or 'undefined' initializer.
@@ -5190,7 +5196,7 @@ namespace ts {
         function isLiteralEnumMember(member: EnumMember) {
             const expr = member.initializer;
             if (!expr) {
-                return !isInAmbientContext(member);
+                return !(member.flags & NodeFlags.Ambient);
             }
             switch (expr.kind) {
                 case SyntaxKind.StringLiteral:
@@ -5866,6 +5872,17 @@ namespace ts {
             return type.modifiersType;
         }
 
+        function getMappedTypeModifiers(type: MappedType): MappedTypeModifiers {
+            return (type.declaration.readonlyToken ? MappedTypeModifiers.Readonly : 0) |
+                (type.declaration.questionToken ? MappedTypeModifiers.Optional : 0);
+        }
+
+        function getCombinedMappedTypeModifiers(type: MappedType): MappedTypeModifiers {
+            const modifiersType = getModifiersTypeFromMappedType(type);
+            return getMappedTypeModifiers(type) |
+                (isGenericMappedType(modifiersType) ? getMappedTypeModifiers(<MappedType>modifiersType) : 0);
+        }
+
         function isPartialMappedType(type: Type) {
             return getObjectFlags(type) & ObjectFlags.Mapped && !!(<MappedType>type).declaration.questionToken;
         }
@@ -6566,7 +6583,7 @@ namespace ts {
                 if (!node) return false;
                 switch (node.kind) {
                     case SyntaxKind.Identifier:
-                        return (<Identifier>node).escapedText === "arguments" && isPartOfExpression(node);
+                        return (<Identifier>node).escapedText === "arguments" && isExpressionNode(node);
 
                     case SyntaxKind.PropertyDeclaration:
                     case SyntaxKind.MethodDeclaration:
@@ -6885,7 +6902,7 @@ namespace ts {
                 const numTypeArguments = length(node.typeArguments);
                 const minTypeArgumentCount = getMinTypeArgumentCount(typeParameters);
                 const isJs = isInJavaScriptFile(node);
-                const isJsImplicitAny = !compilerOptions.noImplicitAny && isJs;
+                const isJsImplicitAny = !noImplicitAny && isJs;
                 if (!isJsImplicitAny && (numTypeArguments < minTypeArgumentCount || numTypeArguments > typeParameters.length)) {
                     const missingAugmentsTag = isJs && node.parent.kind !== SyntaxKind.JSDocAugmentsTag;
                     const diag = minTypeArgumentCount === typeParameters.length
@@ -7292,6 +7309,9 @@ namespace ts {
                 property.type = typeParameter;
                 properties.push(property);
             }
+            const lengthSymbol = createSymbol(SymbolFlags.Property, "length" as __String);
+            lengthSymbol.type = getLiteralType(arity);
+            properties.push(lengthSymbol);
             const type = <GenericType & InterfaceTypeWithDeclaredMembers>createObjectType(ObjectFlags.Tuple | ObjectFlags.Reference);
             type.typeParameters = typeParameters;
             type.outerTypeParameters = undefined;
@@ -7341,28 +7361,12 @@ namespace ts {
             unionIndex?: number;
         }
 
-        function binarySearchTypes(types: Type[], type: Type): number {
-            let low = 0;
-            let high = types.length - 1;
-            const typeId = type.id;
-            while (low <= high) {
-                const middle = low + ((high - low) >> 1);
-                const id = types[middle].id;
-                if (id === typeId) {
-                    return middle;
-                }
-                else if (id > typeId) {
-                    high = middle - 1;
-                }
-                else {
-                    low = middle + 1;
-                }
-            }
-            return ~low;
+        function getTypeId(type: Type) {
+            return type.id;
         }
 
         function containsType(types: Type[], type: Type): boolean {
-            return binarySearchTypes(types, type) >= 0;
+            return binarySearch(types, type, getTypeId, compareValues) >= 0;
         }
 
         // Return true if the given intersection type contains (a) more than one unit type or (b) an object
@@ -7403,7 +7407,7 @@ namespace ts {
                 if (flags & TypeFlags.Number) typeSet.containsNumber = true;
                 if (flags & TypeFlags.StringOrNumberLiteral) typeSet.containsStringOrNumberLiteral = true;
                 const len = typeSet.length;
-                const index = len && type.id > typeSet[len - 1].id ? ~len : binarySearchTypes(typeSet, type);
+                const index = len && type.id > typeSet[len - 1].id ? ~len : binarySearch(typeSet, type, getTypeId, compareValues);
                 if (index < 0) {
                     if (!(flags & TypeFlags.Object && (<ObjectType>type).objectFlags & ObjectFlags.Anonymous &&
                         type.symbol && type.symbol.flags & (SymbolFlags.Function | SymbolFlags.Method) && containsIdenticalType(typeSet, type))) {
@@ -7430,9 +7434,12 @@ namespace ts {
             return false;
         }
 
-        function isSubtypeOfAny(candidate: Type, types: Type[]): boolean {
-            for (const type of types) {
-                if (candidate !== type && isTypeSubtypeOf(candidate, type)) {
+        function isSubtypeOfAny(source: Type, targets: Type[]): boolean {
+            for (const target of targets) {
+                if (source !== target && isTypeSubtypeOf(source, target) && (
+                    !(getObjectFlags(getTargetType(source)) & ObjectFlags.Class) ||
+                    !(getObjectFlags(getTargetType(target)) & ObjectFlags.Class) ||
+                    isTypeDerivedFrom(source, target))) {
                     return true;
                 }
             }
@@ -7579,11 +7586,11 @@ namespace ts {
             }
         }
 
-        // Add the given types to the given type set. Order is preserved, duplicates are removed,
-        // and nested types of the given kind are flattened into the set.
+        // Add the given types to the given type set. Order is preserved, freshness is removed from literal
+        // types, duplicates are removed, and nested types of the given kind are flattened into the set.
         function addTypesToIntersection(typeSet: TypeSet, types: Type[]) {
             for (const type of types) {
-                addTypeToIntersection(typeSet, type);
+                addTypeToIntersection(typeSet, getRegularTypeOfLiteralType(type));
             }
         }
 
@@ -7672,7 +7679,7 @@ namespace ts {
 
         function getIndexTypeOrString(type: Type): Type {
             const indexType = getIndexType(type);
-            return indexType !== neverType ? indexType : stringType;
+            return indexType.flags & TypeFlags.Never ? stringType : indexType;
         }
 
         function getTypeFromTypeOperatorNode(node: TypeOperatorNode) {
@@ -7981,11 +7988,16 @@ namespace ts {
                 }
             }
 
-            const spread = createAnonymousType(undefined, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
+            const spread = createAnonymousType(
+                symbol,
+                members,
+                emptyArray,
+                emptyArray,
+                getNonReadonlyIndexSignature(stringIndexInfo),
+                getNonReadonlyIndexSignature(numberIndexInfo));
             spread.flags |= propagatedFlags;
             spread.flags |= TypeFlags.FreshLiteral | TypeFlags.ContainsObjectLiteral;
-            (spread as ObjectType).objectFlags |= ObjectFlags.ObjectLiteral;
-            spread.symbol = symbol;
+            (spread as ObjectType).objectFlags |= (ObjectFlags.ObjectLiteral | ObjectFlags.ContainsSpread);
             return spread;
         }
 
@@ -8001,6 +8013,13 @@ namespace ts {
             return result;
         }
 
+        function getNonReadonlyIndexSignature(index: IndexInfo) {
+            if (index && index.isReadonly) {
+                return createIndexInfo(index.type, /*isReadonly*/ false, index.declaration);
+            }
+            return index;
+        }
+
         function isClassMethod(prop: Symbol) {
             return prop.flags & SymbolFlags.Method && find(prop.declarations, decl => isClassLike(decl.parent));
         }
@@ -8555,12 +8574,19 @@ namespace ts {
             return isTypeRelatedTo(source, target, assignableRelation);
         }
 
-        // A type S is considered to be an instance of a type T if S and T are the same type or if S is a
-        // subtype of T but not structurally identical to T. This specifically means that two distinct but
-        // structurally identical types (such as two classes) are not considered instances of each other.
-        function isTypeInstanceOf(source: Type, target: Type): boolean {
-            return getTargetType(source) === getTargetType(target) || isTypeSubtypeOf(source, target) && !isTypeIdenticalTo(source, target);
-        }
+        // An object type S is considered to be derived from an object type T if
+        // S is a union type and every constituent of S is derived from T,
+        // T is a union type and S is derived from at least one constituent of T, or
+        // T is one of the global types Object and Function and S is a subtype of T, or
+        // T occurs directly or indirectly in an 'extends' clause of S.
+        // Note that this check ignores type parameters and only considers the
+        // inheritance hierarchy.
+        function isTypeDerivedFrom(source: Type, target: Type): boolean {
+            return source.flags & TypeFlags.Union ? every((<UnionType>source).types, t => isTypeDerivedFrom(t, target)) :
+                target.flags & TypeFlags.Union ? some((<UnionType>target).types, t => isTypeDerivedFrom(source, t)) :
+                target === globalObjectType || target === globalFunctionType ? isTypeSubtypeOf(source, target) :
+                hasBaseType(source, getTargetType(target));
+            }
 
         /**
          * This is *not* a bi-directional relationship.
@@ -8842,8 +8868,8 @@ namespace ts {
         function isSimpleTypeRelatedTo(source: Type, target: Type, relation: Map<RelationComparisonResult>, errorReporter?: ErrorReporter) {
             const s = source.flags;
             const t = target.flags;
-            if (t & TypeFlags.Never) return false;
             if (t & TypeFlags.Any || s & TypeFlags.Never) return true;
+            if (t & TypeFlags.Never) return false;
             if (s & TypeFlags.StringLike && t & TypeFlags.String) return true;
             if (s & TypeFlags.StringLiteral && s & TypeFlags.EnumLiteral &&
                 t & TypeFlags.StringLiteral && !(t & TypeFlags.EnumLiteral) &&
@@ -9026,7 +9052,7 @@ namespace ts {
 
                 if (isSimpleTypeRelatedTo(source, target, relation, reportErrors ? reportError : undefined)) return Ternary.True;
 
-                if (getObjectFlags(source) & ObjectFlags.ObjectLiteral && source.flags & TypeFlags.FreshLiteral) {
+                if (isObjectLiteralType(source) && source.flags & TypeFlags.FreshLiteral) {
                     if (hasExcessProperties(<FreshObjectLiteralType>source, target, reportErrors)) {
                         if (reportErrors) {
                             reportRelationError(headMessage, source, target);
@@ -9229,20 +9255,24 @@ namespace ts {
                 return Ternary.False;
             }
 
+            // Keep this up-to-date with the same logic within `getApparentTypeOfContextualType`, since they should behave similarly
             function findMatchingDiscriminantType(source: Type, target: UnionOrIntersectionType) {
                 let match: Type;
                 const sourceProperties = getPropertiesOfObjectType(source);
                 if (sourceProperties) {
-                    const sourceProperty = findSingleDiscriminantProperty(sourceProperties, target);
-                    if (sourceProperty) {
-                        const sourceType = getTypeOfSymbol(sourceProperty);
-                        for (const type of target.types) {
-                            const targetType = getTypeOfPropertyOfType(type, sourceProperty.escapedName);
-                            if (targetType && isRelatedTo(sourceType, targetType)) {
-                                if (match) {
-                                    return undefined;
+                    const sourcePropertiesFiltered = findDiscriminantProperties(sourceProperties, target);
+                    if (sourcePropertiesFiltered) {
+                        for (const sourceProperty of sourcePropertiesFiltered) {
+                            const sourceType = getTypeOfSymbol(sourceProperty);
+                            for (const type of target.types) {
+                                const targetType = getTypeOfPropertyOfType(type, sourceProperty.escapedName);
+                                if (targetType && isRelatedTo(sourceType, targetType)) {
+                                    if (type === match) continue; // Finding multiple fields which discriminate to the same type is fine
+                                    if (match) {
+                                        return undefined;
+                                    }
+                                    match = type;
                                 }
-                                match = type;
                             }
                         }
                     }
@@ -9413,6 +9443,7 @@ namespace ts {
 
             function structuredTypeRelatedTo(source: Type, target: Type, reportErrors: boolean): Ternary {
                 let result: Ternary;
+                let originalErrorInfo: DiagnosticMessageChain;
                 const saveErrorInfo = errorInfo;
                 if (target.flags & TypeFlags.TypeParameter) {
                     // A source type { [P in keyof T]: X } is related to a target type T if X is related to T[P].
@@ -9453,32 +9484,30 @@ namespace ts {
                         }
                     }
                 }
+                else if (isGenericMappedType(target) && !isGenericMappedType(source) && getConstraintTypeFromMappedType(<MappedType>target) === getIndexType(source)) {
+                    // A source type T is related to a target type { [P in keyof T]: X } if T[P] is related to X.
+                    const indexedAccessType = getIndexedAccessType(source, getTypeParameterFromMappedType(<MappedType>target));
+                    const templateType = getTemplateTypeFromMappedType(<MappedType>target);
+                    if (result = isRelatedTo(indexedAccessType, templateType, reportErrors)) {
+                        errorInfo = saveErrorInfo;
+                        return result;
+                    }
+                }
 
                 if (source.flags & TypeFlags.TypeParameter) {
-                    // A source type T is related to a target type { [P in keyof T]: X } if T[P] is related to X.
-                    if (getObjectFlags(target) & ObjectFlags.Mapped && getConstraintTypeFromMappedType(<MappedType>target) === getIndexType(source)) {
-                        const indexedAccessType = getIndexedAccessType(source, getTypeParameterFromMappedType(<MappedType>target));
-                        const templateType = getTemplateTypeFromMappedType(<MappedType>target);
-                        if (result = isRelatedTo(indexedAccessType, templateType, reportErrors)) {
+                    let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
+                    // A type parameter with no constraint is not related to the non-primitive object type.
+                    if (constraint || !(target.flags & TypeFlags.NonPrimitive)) {
+                        if (!constraint || constraint.flags & TypeFlags.Any) {
+                            constraint = emptyObjectType;
+                        }
+                        // Report constraint errors only if the constraint is not the empty object type
+                        const reportConstraintErrors = reportErrors && constraint !== emptyObjectType;
+                        if (result = isRelatedTo(constraint, target, reportConstraintErrors)) {
                             errorInfo = saveErrorInfo;
                             return result;
                         }
                     }
-                    else {
-                        let constraint = getConstraintOfTypeParameter(<TypeParameter>source);
-                        // A type parameter with no constraint is not related to the non-primitive object type.
-                        if (constraint || !(target.flags & TypeFlags.NonPrimitive)) {
-                            if (!constraint || constraint.flags & TypeFlags.Any) {
-                                constraint = emptyObjectType;
-                            }
-                            // Report constraint errors only if the constraint is not the empty object type
-                            const reportConstraintErrors = reportErrors && constraint !== emptyObjectType;
-                            if (result = isRelatedTo(constraint, target, reportConstraintErrors)) {
-                                errorInfo = saveErrorInfo;
-                                return result;
-                            }
-                        }
-                    }
                 }
                 else if (source.flags & TypeFlags.IndexedAccess) {
                     // A type S[K] is related to a type T if A[K] is related to T, where K is string-like and
@@ -9494,6 +9523,7 @@ namespace ts {
                         // if we have indexed access types with identical index types, see if relationship holds for
                         // the two object types.
                         if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
+                            errorInfo = saveErrorInfo;
                             return result;
                         }
                     }
@@ -9525,6 +9555,10 @@ namespace ts {
                             if (!(reportErrors && some(variances, v => v === Variance.Invariant))) {
                                 return Ternary.False;
                             }
+                            // We remember the original error information so we can restore it in case the structural
+                            // comparison unexpectedly succeeds. This can happen when the structural comparison result
+                            // is a Ternary.Maybe for example caused by the recursion depth limiter.
+                            originalErrorInfo = errorInfo;
                             errorInfo = saveErrorInfo;
                         }
                     }
@@ -9563,8 +9597,11 @@ namespace ts {
                             }
                         }
                         if (result) {
-                            errorInfo = saveErrorInfo;
-                            return result;
+                            if (!originalErrorInfo) {
+                                errorInfo = saveErrorInfo;
+                                return result;
+                            }
+                            errorInfo = originalErrorInfo;
                         }
                     }
                 }
@@ -9575,13 +9612,10 @@ namespace ts {
             // related to Y, where X' is an instantiation of X in which P is replaced with Q. Notice
             // that S and T are contra-variant whereas X and Y are co-variant.
             function mappedTypeRelatedTo(source: MappedType, target: MappedType, reportErrors: boolean): Ternary {
-                const sourceReadonly = !!source.declaration.readonlyToken;
-                const sourceOptional = !!source.declaration.questionToken;
-                const targetReadonly = !!target.declaration.readonlyToken;
-                const targetOptional = !!target.declaration.questionToken;
-                const modifiersRelated = relation === identityRelation ?
-                    sourceReadonly === targetReadonly && sourceOptional === targetOptional :
-                    relation === comparableRelation || !sourceOptional || targetOptional;
+                const modifiersRelated = relation === comparableRelation || (
+                    relation === identityRelation ? getMappedTypeModifiers(source) === getMappedTypeModifiers(target) :
+                        !(getCombinedMappedTypeModifiers(source) & MappedTypeModifiers.Optional) ||
+                        getCombinedMappedTypeModifiers(target) & MappedTypeModifiers.Optional);
                 if (modifiersRelated) {
                     let result: Ternary;
                     if (result = isRelatedTo(getConstraintTypeFromMappedType(<MappedType>target), getConstraintTypeFromMappedType(<MappedType>source), reportErrors)) {
@@ -9596,7 +9630,7 @@ namespace ts {
                 if (relation === identityRelation) {
                     return propertiesIdenticalTo(source, target);
                 }
-                const requireOptionalProperties = relation === subtypeRelation && !(getObjectFlags(source) & ObjectFlags.ObjectLiteral);
+                const requireOptionalProperties = relation === subtypeRelation && !isObjectLiteralType(source) && !isEmptyArrayLiteralType(source);
                 const unmatchedProperty = getUnmatchedProperty(source, target, requireOptionalProperties);
                 if (unmatchedProperty) {
                     if (reportErrors) {
@@ -9604,6 +9638,19 @@ namespace ts {
                     }
                     return Ternary.False;
                 }
+                if (isObjectLiteralType(target)) {
+                    for (const sourceProp of getPropertiesOfType(source)) {
+                        if (!getPropertyOfObjectType(target, sourceProp.escapedName)) {
+                            const sourceType = getTypeOfSymbol(sourceProp);
+                            if (!(sourceType === undefinedType || sourceType === undefinedWideningType)) {
+                                if (reportErrors) {
+                                    reportError(Diagnostics.Property_0_does_not_exist_on_type_1, symbolToString(sourceProp), typeToString(target));
+                                }
+                                return Ternary.False;
+                            }
+                        }
+                    }
+                }
                 let result = Ternary.True;
                 const properties = getPropertiesOfObjectType(target);
                 for (const targetProp of properties) {
@@ -10291,6 +10338,11 @@ namespace ts {
                 !(type.flags & TypeFlags.Nullable) && isTypeAssignableTo(type, anyReadonlyArrayType);
         }
 
+        function isEmptyArrayLiteralType(type: Type): boolean {
+            const elementType = isArrayType(type) ? (<TypeReference>type).typeArguments[0] : undefined;
+            return elementType === undefinedWideningType || elementType === implicitNeverType;
+        }
+
         function isTupleLikeType(type: Type): boolean {
             return !!getPropertyOfType(type, "0" as __String);
         }
@@ -10425,7 +10477,7 @@ namespace ts {
          * Leave signatures alone since they are not subject to the check.
          */
         function getRegularTypeOfObjectLiteral(type: Type): Type {
-            if (!(getObjectFlags(type) & ObjectFlags.ObjectLiteral && type.flags & TypeFlags.FreshLiteral)) {
+            if (!(isObjectLiteralType(type) && type.flags & TypeFlags.FreshLiteral)) {
                 return type;
             }
             const regularType = (<FreshObjectLiteralType>type).regularType;
@@ -10447,18 +10499,74 @@ namespace ts {
             return regularNew;
         }
 
-        function getWidenedProperty(prop: Symbol): Symbol {
+        function createWideningContext(parent: WideningContext, propertyName: __String, siblings: Type[]): WideningContext {
+            return { parent, propertyName, siblings, resolvedPropertyNames: undefined };
+        }
+
+        function getSiblingsOfContext(context: WideningContext): Type[] {
+            if (!context.siblings) {
+                const siblings: Type[] = [];
+                for (const type of getSiblingsOfContext(context.parent)) {
+                    if (isObjectLiteralType(type)) {
+                        const prop = getPropertyOfObjectType(type, context.propertyName);
+                        if (prop) {
+                            forEachType(getTypeOfSymbol(prop), t => {
+                                siblings.push(t);
+                            });
+                        }
+                    }
+                }
+                context.siblings = siblings;
+            }
+            return context.siblings;
+        }
+
+        function getPropertyNamesOfContext(context: WideningContext): __String[] {
+            if (!context.resolvedPropertyNames) {
+                const names = createMap<boolean>() as UnderscoreEscapedMap<boolean>;
+                for (const t of getSiblingsOfContext(context)) {
+                    if (isObjectLiteralType(t) && !(getObjectFlags(t) & ObjectFlags.ContainsSpread)) {
+                        for (const prop of getPropertiesOfType(t)) {
+                            names.set(prop.escapedName, true);
+                        }
+                    }
+                }
+                context.resolvedPropertyNames = arrayFrom(names.keys());
+            }
+            return context.resolvedPropertyNames;
+        }
+
+        function getWidenedProperty(prop: Symbol, context: WideningContext): Symbol {
             const original = getTypeOfSymbol(prop);
-            const widened = getWidenedType(original);
+            const propContext = context && createWideningContext(context, prop.escapedName, /*siblings*/ undefined);
+            const widened = getWidenedTypeWithContext(original, propContext);
             return widened === original ? prop : createSymbolWithType(prop, widened);
         }
 
-        function getWidenedTypeOfObjectLiteral(type: Type): Type {
+        function getUndefinedProperty(name: __String) {
+            const cached = undefinedProperties.get(name);
+            if (cached) {
+                return cached;
+            }
+            const result = createSymbol(SymbolFlags.Property | SymbolFlags.Optional, name);
+            result.type = undefinedType;
+            undefinedProperties.set(name, result);
+            return result;
+        }
+
+        function getWidenedTypeOfObjectLiteral(type: Type, context: WideningContext): Type {
             const members = createSymbolTable();
             for (const prop of getPropertiesOfObjectType(type)) {
                 // Since get accessors already widen their return value there is no need to
                 // widen accessor based properties here.
-                members.set(prop.escapedName, prop.flags & SymbolFlags.Property ? getWidenedProperty(prop) : prop);
+                members.set(prop.escapedName, prop.flags & SymbolFlags.Property ? getWidenedProperty(prop, context) : prop);
+            }
+            if (context) {
+                for (const name of getPropertyNamesOfContext(context)) {
+                    if (!members.has(name)) {
+                        members.set(name, getUndefinedProperty(name));
+                    }
+                }
             }
             const stringIndexInfo = getIndexInfoOfType(type, IndexKind.String);
             const numberIndexInfo = getIndexInfoOfType(type, IndexKind.Number);
@@ -10467,20 +10575,25 @@ namespace ts {
                 numberIndexInfo && createIndexInfo(getWidenedType(numberIndexInfo.type), numberIndexInfo.isReadonly));
         }
 
-        function getWidenedConstituentType(type: Type): Type {
-            return type.flags & TypeFlags.Nullable ? type : getWidenedType(type);
+        function getWidenedType(type: Type) {
+            return getWidenedTypeWithContext(type, /*context*/ undefined);
         }
 
-        function getWidenedType(type: Type): Type {
+        function getWidenedTypeWithContext(type: Type, context: WideningContext): Type {
             if (type.flags & TypeFlags.RequiresWidening) {
                 if (type.flags & TypeFlags.Nullable) {
                     return anyType;
                 }
-                if (getObjectFlags(type) & ObjectFlags.ObjectLiteral) {
-                    return getWidenedTypeOfObjectLiteral(type);
+                if (isObjectLiteralType(type)) {
+                    return getWidenedTypeOfObjectLiteral(type, context);
                 }
                 if (type.flags & TypeFlags.Union) {
-                    return getUnionType(sameMap((<UnionType>type).types, getWidenedConstituentType));
+                    const unionContext = context || createWideningContext(/*parent*/ undefined, /*propertyName*/ undefined, (<UnionType>type).types);
+                    const widenedTypes = sameMap((<UnionType>type).types, t => t.flags & TypeFlags.Nullable ? t : getWidenedTypeWithContext(t, unionContext));
+                    // Widening an empty object literal transitions from a highly restrictive type to
+                    // a highly inclusive one. For that reason we perform subtype reduction here if the
+                    // union includes empty object types (e.g. reducing {} | string to just {}).
+                    return getUnionType(widenedTypes, some(widenedTypes, isEmptyObjectType));
                 }
                 if (isArrayType(type) || isTupleType(type)) {
                     return createTypeReference((<TypeReference>type).target, sameMap((<TypeReference>type).typeArguments, getWidenedType));
@@ -10502,28 +10615,35 @@ namespace ts {
          */
         function reportWideningErrorsInType(type: Type): boolean {
             let errorReported = false;
-            if (type.flags & TypeFlags.Union) {
-                for (const t of (<UnionType>type).types) {
-                    if (reportWideningErrorsInType(t)) {
+            if (type.flags & TypeFlags.ContainsWideningType) {
+                if (type.flags & TypeFlags.Union) {
+                    if (some((<UnionType>type).types, isEmptyObjectType)) {
                         errorReported = true;
                     }
+                    else {
+                        for (const t of (<UnionType>type).types) {
+                            if (reportWideningErrorsInType(t)) {
+                                errorReported = true;
+                            }
+                        }
+                    }
                 }
-            }
-            if (isArrayType(type) || isTupleType(type)) {
-                for (const t of (<TypeReference>type).typeArguments) {
-                    if (reportWideningErrorsInType(t)) {
-                        errorReported = true;
+                if (isArrayType(type) || isTupleType(type)) {
+                    for (const t of (<TypeReference>type).typeArguments) {
+                        if (reportWideningErrorsInType(t)) {
+                            errorReported = true;
+                        }
                     }
                 }
-            }
-            if (getObjectFlags(type) & ObjectFlags.ObjectLiteral) {
-                for (const p of getPropertiesOfObjectType(type)) {
-                    const t = getTypeOfSymbol(p);
-                    if (t.flags & TypeFlags.ContainsWideningType) {
-                        if (!reportWideningErrorsInType(t)) {
-                            error(p.valueDeclaration, Diagnostics.Object_literal_s_property_0_implicitly_has_an_1_type, symbolName(p), typeToString(getWidenedType(t)));
+                if (isObjectLiteralType(type)) {
+                    for (const p of getPropertiesOfObjectType(type)) {
+                        const t = getTypeOfSymbol(p);
+                        if (t.flags & TypeFlags.ContainsWideningType) {
+                            if (!reportWideningErrorsInType(t)) {
+                                error(p.valueDeclaration, Diagnostics.Object_literal_s_property_0_implicitly_has_an_1_type, symbolName(p), typeToString(getWidenedType(t)));
+                            }
+                            errorReported = true;
                         }
-                        errorReported = true;
                     }
                 }
             }
@@ -10703,7 +10823,7 @@ namespace ts {
         }
 
         function getUnmatchedProperty(source: Type, target: Type, requireOptionalProperties: boolean) {
-            const properties = getPropertiesOfObjectType(target);
+            const properties = target.flags & TypeFlags.Intersection ? getPropertiesOfUnionOrIntersectionType(<IntersectionType>target) : getPropertiesOfObjectType(target);
             for (const targetProp of properties) {
                 if (requireOptionalProperties || !(targetProp.flags & SymbolFlags.Optional)) {
                     const sourceProp = getPropertyOfType(source, targetProp.escapedName);
@@ -10777,9 +10897,10 @@ namespace ts {
                     // Because the anyFunctionType is internal, it should not be exposed to the user by adding
                     // it as an inference candidate. Hopefully, a better candidate will come along that does
                     // not contain anyFunctionType when we come back to this argument for its second round
-                    // of inference. Also, we exclude inferences for silentNeverType which is used as a wildcard
-                    // when constructing types from type parameters that had no inference candidates.
-                    if (source.flags & TypeFlags.ContainsAnyFunctionType || source === silentNeverType) {
+                    // of inference. Also, we exclude inferences for silentNeverType (which is used as a wildcard
+                    // when constructing types from type parameters that had no inference candidates) and
+                    // implicitNeverType (which is used as the element type for empty array literals).
+                    if (source.flags & TypeFlags.ContainsAnyFunctionType || source === silentNeverType || source === implicitNeverType) {
                         return;
                     }
                     const inference = getInferenceInfoForType(target);
@@ -11029,11 +11150,28 @@ namespace ts {
             return constraint && maybeTypeOfKind(constraint, TypeFlags.Primitive | TypeFlags.Index);
         }
 
+        function isObjectLiteralType(type: Type) {
+            return !!(getObjectFlags(type) & ObjectFlags.ObjectLiteral);
+        }
+
+        function widenObjectLiteralCandidates(candidates: Type[]): Type[] {
+            if (candidates.length > 1) {
+                const objectLiterals = filter(candidates, isObjectLiteralType);
+                if (objectLiterals.length) {
+                    const objectLiteralsType = getWidenedType(getUnionType(objectLiterals, /*subtypeReduction*/ true));
+                    return concatenate(filter(candidates, t => !isObjectLiteralType(t)), [objectLiteralsType]);
+                }
+            }
+            return candidates;
+        }
+
         function getInferredType(context: InferenceContext, index: number): Type {
             const inference = context.inferences[index];
             let inferredType = inference.inferredType;
             if (!inferredType) {
                 if (inference.candidates) {
+                    // Extract all object literal types and replace them with a single widened and normalized type.
+                    const candidates = widenObjectLiteralCandidates(inference.candidates);
                     // We widen inferred literal types if
                     // all inferences were made to top-level ocurrences of the type parameter, and
                     // the type parameter has no constraint or its constraint includes no primitive or literal types, and
@@ -11042,7 +11180,7 @@ namespace ts {
                     const widenLiteralTypes = inference.topLevel &&
                         !hasPrimitiveConstraint(inference.typeParameter) &&
                         (inference.isFixed || !isTypeParameterAtTopLevel(getReturnTypeOfSignature(signature), inference.typeParameter));
-                    const baseCandidates = widenLiteralTypes ? sameMap(inference.candidates, getWidenedLiteralType) : inference.candidates;
+                    const baseCandidates = widenLiteralTypes ? sameMap(candidates, getWidenedLiteralType) : candidates;
                     // If all inferences were made from contravariant positions, infer a common subtype. Otherwise, if
                     // union types were requested or if all inferences were made from the return type position, infer a
                     // union type. Otherwise, infer a common supertype.
@@ -11248,14 +11386,15 @@ namespace ts {
             return false;
         }
 
-        function findSingleDiscriminantProperty(sourceProperties: Symbol[], target: Type): Symbol | undefined {
-            let result: Symbol;
+        function findDiscriminantProperties(sourceProperties: Symbol[], target: Type): Symbol[] | undefined {
+            let result: Symbol[];
             for (const sourceProperty of sourceProperties) {
                 if (isDiscriminantProperty(target, sourceProperty.escapedName)) {
                     if (result) {
-                        return undefined;
+                        result.push(sourceProperty);
+                        continue;
                     }
-                    result = sourceProperty;
+                    result = [sourceProperty];
                 }
             }
             return result;
@@ -12309,7 +12448,7 @@ namespace ts {
                 }
 
                 if (targetType) {
-                    return getNarrowedType(type, targetType, assumeTrue, isTypeInstanceOf);
+                    return getNarrowedType(type, targetType, assumeTrue, isTypeDerivedFrom);
                 }
 
                 return type;
@@ -12416,7 +12555,7 @@ namespace ts {
                 if (isRightSideOfQualifiedNameOrPropertyAccess(location)) {
                     location = location.parent;
                 }
-                if (isPartOfExpression(location) && !isAssignmentTarget(location)) {
+                if (isExpressionNode(location) && !isAssignmentTarget(location)) {
                     const type = getTypeOfExpression(<Expression>location);
                     if (getExportSymbolOfValueSymbolIfExported(getNodeLinks(location).resolvedSymbol) === symbol) {
                         return type;
@@ -12639,7 +12778,7 @@ namespace ts {
             const assumeInitialized = isParameter || isAlias || isOuterVariable ||
                 type !== autoType && type !== autoArrayType && (!strictNullChecks || (type.flags & TypeFlags.Any) !== 0 || isInTypeQuery(node) || node.parent.kind === SyntaxKind.ExportSpecifier) ||
                 node.parent.kind === SyntaxKind.NonNullExpression ||
-                isInAmbientContext(declaration);
+                declaration.flags & NodeFlags.Ambient;
             const initialType = assumeInitialized ? (isParameter ? removeOptionalityFromDeclaredType(type, getRootDeclaration(declaration) as VariableLikeDeclaration) : type) :
                 type === autoType || type === autoArrayType ? undefinedType :
                     getNullableType(type, TypeFlags.Undefined);
@@ -13491,7 +13630,13 @@ namespace ts {
             // JSX expression can appear in two position : JSX Element's children or JSX attribute
             const jsxAttributes = isJsxAttributeLike(node.parent) ?
                 node.parent.parent :
-                node.parent.openingElement.attributes; // node.parent is JsxElement
+                    isJsxElement(node.parent) ?
+                        node.parent.openingElement.attributes :
+                        undefined; // node.parent is JsxFragment with no attributes
+
+            if (!jsxAttributes) {
+                return undefined; // don't check children of a fragment
+            }
 
             // When we trying to resolve JsxOpeningLikeElement as a stateless function element, we will already give its attributes a contextual type
             // which is a type of the parameter of the signature we are trying out.
@@ -13537,8 +13682,32 @@ namespace ts {
         // Return the contextual type for a given expression node. During overload resolution, a contextual type may temporarily
         // be "pushed" onto a node using the contextualType property.
         function getApparentTypeOfContextualType(node: Expression): Type {
-            const type = getContextualType(node);
-            return type && getApparentType(type);
+            let contextualType = getContextualType(node);
+            contextualType = contextualType && mapType(contextualType, getApparentType);
+            if (!(contextualType && contextualType.flags & TypeFlags.Union && isObjectLiteralExpression(node))) {
+                return contextualType;
+            }
+            // Keep the below up-to-date with the work done within `isRelatedTo` by `findMatchingDiscriminantType`
+            let match: Type | undefined;
+            propLoop: for (const prop of node.properties) {
+                if (!prop.symbol) continue;
+                if (prop.kind !== SyntaxKind.PropertyAssignment) continue;
+                if (isDiscriminantProperty(contextualType, prop.symbol.escapedName)) {
+                    const discriminatingType = getTypeOfNode(prop.initializer);
+                    for (const type of (contextualType as UnionType).types) {
+                        const targetType = getTypeOfPropertyOfType(type, prop.symbol.escapedName);
+                        if (targetType && checkTypeAssignableTo(discriminatingType, targetType, /*errorNode*/ undefined)) {
+                            if (match) {
+                                if (type === match) continue; // Finding multiple fields which discriminate to the same type is fine
+                                match = undefined;
+                                break propLoop;
+                            }
+                            match = type;
+                        }
+                    }
+                }
+            }
+            return match || contextualType;
         }
 
         /**
@@ -13771,7 +13940,6 @@ namespace ts {
                     type.pattern = node;
                     return type;
                 }
-                const contextualType = getApparentTypeOfContextualType(node);
                 if (contextualType && contextualTypeIsTupleLikeType(contextualType)) {
                     const pattern = contextualType.pattern;
                     // If array literal is contextually typed by a binding pattern or an assignment pattern, pad the resulting
@@ -13798,7 +13966,7 @@ namespace ts {
             }
             return createArrayType(elementTypes.length ?
                 getUnionType(elementTypes, /*subtypeReduction*/ true) :
-                strictNullChecks ? neverType : undefinedWideningType);
+                strictNullChecks ? implicitNeverType : undefinedWideningType);
         }
 
         function isNumericName(name: DeclarationName): boolean {
@@ -14071,13 +14239,13 @@ namespace ts {
         }
 
         function checkJsxSelfClosingElement(node: JsxSelfClosingElement): Type {
-            checkJsxOpeningLikeElement(node);
+            checkJsxOpeningLikeElementOrOpeningFragment(node);
             return getJsxGlobalElementType() || anyType;
         }
 
         function checkJsxElement(node: JsxElement): Type {
             // Check attributes
-            checkJsxOpeningLikeElement(node.openingElement);
+            checkJsxOpeningLikeElementOrOpeningFragment(node.openingElement);
 
             // Perform resolution on the closing tag so that rename/go to definition/etc work
             if (isJsxIntrinsicIdentifier(node.closingElement.tagName)) {
@@ -14090,6 +14258,16 @@ namespace ts {
             return getJsxGlobalElementType() || anyType;
         }
 
+        function checkJsxFragment(node: JsxFragment): Type {
+            checkJsxOpeningLikeElementOrOpeningFragment(node.openingFragment);
+
+            if (compilerOptions.jsx === JsxEmit.React && compilerOptions.jsxFactory) {
+                error(node, Diagnostics.JSX_fragment_is_not_supported_when_using_jsxFactory);
+            }
+
+            return getJsxGlobalElementType() || anyType;
+        }
+
         /**
          * Returns true iff the JSX element name would be a valid JS identifier, ignoring restrictions about keywords not being identifiers
          */
@@ -14753,14 +14931,19 @@ namespace ts {
             }
         }
 
-        function checkJsxOpeningLikeElement(node: JsxOpeningLikeElement) {
-            checkGrammarJsxElement(node);
+        function checkJsxOpeningLikeElementOrOpeningFragment(node: JsxOpeningLikeElement | JsxOpeningFragment) {
+            const isNodeOpeningLikeElement = isJsxOpeningLikeElement(node);
+
+            if (isNodeOpeningLikeElement) {
+                checkGrammarJsxElement(<JsxOpeningLikeElement>node);
+            }
             checkJsxPreconditions(node);
             // The reactNamespace/jsxFactory's root symbol should be marked as 'used' so we don't incorrectly elide its import.
             // And if there is no reactNamespace/jsxFactory's symbol in scope when targeting React emit, we should issue an error.
             const reactRefErr = diagnostics && compilerOptions.jsx === JsxEmit.React ? Diagnostics.Cannot_find_name_0 : undefined;
             const reactNamespace = getJsxNamespace();
-            const reactSym = resolveName(node.tagName, reactNamespace, SymbolFlags.Value, reactRefErr, reactNamespace, /*isUse*/ true);
+            const reactLocation = isNodeOpeningLikeElement ? (<JsxOpeningLikeElement>node).tagName : node;
+            const reactSym = resolveName(reactLocation, reactNamespace, SymbolFlags.Value, reactRefErr, reactNamespace, /*isUse*/ true);
             if (reactSym) {
                 // Mark local symbol as referenced here because it might not have been marked
                 // if jsx emit was not react as there wont be error being emitted
@@ -14772,7 +14955,9 @@ namespace ts {
                 }
             }
 
-            checkJsxAttributesAssignableToTagNameAttributes(node);
+            if (isNodeOpeningLikeElement) {
+                checkJsxAttributesAssignableToTagNameAttributes(<JsxOpeningLikeElement>node);
+            }
         }
 
         /**
@@ -14928,12 +15113,11 @@ namespace ts {
                 }
             }
 
-            // Referencing Abstract Properties within Constructors is not allowed
-            if ((flags & ModifierFlags.Abstract) && symbolHasNonMethodDeclaration(prop)) {
+            // Referencing abstract properties within their own constructors is not allowed
+            if ((flags & ModifierFlags.Abstract) && isThisProperty(node) && symbolHasNonMethodDeclaration(prop)) {
                 const declaringClassDeclaration = <ClassLikeDeclaration>getClassLikeDeclarationOfSymbol(getParentOfSymbol(prop));
-
-                if (declaringClassDeclaration && isNodeWithinConstructor(node, declaringClassDeclaration)) {
-                    error(errorNode, Diagnostics.Abstract_property_0_in_class_1_cannot_be_accessed_in_the_constructor, symbolToString(prop), typeToString(getDeclaringClass(prop)));
+                if (declaringClassDeclaration && isNodeWithinConstructorOfClass(node, declaringClassDeclaration)) {
+                    error(errorNode, Diagnostics.Abstract_property_0_in_class_1_cannot_be_accessed_in_the_constructor, symbolToString(prop), getTextOfIdentifierOrLiteral(declaringClassDeclaration.name));
                     return false;
                 }
             }
@@ -14977,12 +15161,11 @@ namespace ts {
             if (flags & ModifierFlags.Static) {
                 return true;
             }
-            // An instance property must be accessed through an instance of the enclosing class
-            if (type.flags & TypeFlags.TypeParameter && (type as TypeParameter).isThisType) {
+             if (type.flags & TypeFlags.TypeParameter) {
                 // get the original type -- represented as the type constraint of the 'this' type
-                type = getConstraintOfTypeParameter(<TypeParameter>type);
+                type = (type as TypeParameter).isThisType ? getConstraintOfTypeParameter(<TypeParameter>type) : getBaseConstraintOfType(<TypeParameter>type);
             }
-            if (!(getObjectFlags(getTargetType(type)) & ObjectFlags.ClassOrInterface && hasBaseType(type, enclosingClass))) {
+            if (!type || !hasBaseType(type, enclosingClass)) {
                 error(errorNode, Diagnostics.Property_0_is_protected_and_only_accessible_through_an_instance_of_class_1, symbolToString(prop), typeToString(enclosingClass));
                 return false;
             }
@@ -15039,7 +15222,7 @@ namespace ts {
                     if (indexInfo.isReadonly && (isAssignmentTarget(node) || isDeleteTarget(node))) {
                         error(node, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(apparentType));
                     }
-                    return indexInfo.type;
+                    return getFlowTypeOfPropertyAccess(node, /*prop*/ undefined, indexInfo.type, getAssignmentTargetKind(node));
                 }
                 if (right.escapedText && !checkAndReportErrorForExtendingInterface(node)) {
                     reportNonexistentProperty(right, type.flags & TypeFlags.TypeParameter && (type as TypeParameter).isThisType ? apparentType : type);
@@ -15064,16 +15247,21 @@ namespace ts {
                     return unknownType;
                 }
             }
+            return getFlowTypeOfPropertyAccess(node, prop, propType, assignmentKind);
+        }
 
-            // Only compute control flow type if this is a property access expression that isn't an
-            // assignment target, and the referenced property was declared as a variable, property,
-            // accessor, or optional method.
-            if (node.kind !== SyntaxKind.PropertyAccessExpression || assignmentKind === AssignmentKind.Definite ||
-                !(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) &&
-                !(prop.flags & SymbolFlags.Method && propType.flags & TypeFlags.Union)) {
-                return propType;
+        /**
+         * Only compute control flow type if this is a property access expression that isn't an
+         * assignment target, and the referenced property was declared as a variable, property,
+         * accessor, or optional method.
+         */
+        function getFlowTypeOfPropertyAccess(node: PropertyAccessExpression | QualifiedName, prop: Symbol | undefined, type: Type, assignmentKind: AssignmentKind) {
+            if (node.kind !== SyntaxKind.PropertyAccessExpression ||
+                assignmentKind === AssignmentKind.Definite ||
+                prop && !(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) && !(prop.flags & SymbolFlags.Method && type.flags & TypeFlags.Union)) {
+                return type;
             }
-            const flowType = getFlowTypeOfReference(node, propType);
+            const flowType = getFlowTypeOfReference(node, type);
             return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
         }
 
@@ -15090,7 +15278,7 @@ namespace ts {
             }
             else if (valueDeclaration.kind === SyntaxKind.ClassDeclaration &&
                 node.parent.kind !== SyntaxKind.TypeReference &&
-                !isInAmbientContext(valueDeclaration) &&
+                !(valueDeclaration.flags & NodeFlags.Ambient) &&
                 !isBlockScopedNameDeclaredBeforeUse(valueDeclaration, right)) {
                 error(right, Diagnostics.Class_0_used_before_its_declaration, idText(right));
             }
@@ -15105,7 +15293,7 @@ namespace ts {
                         // We might be in `a = { b: this.b }`, so keep looking. See `tests/cases/compiler/useBeforeDeclaration_propertyAssignment.ts`.
                         return false;
                     default:
-                        return isPartOfExpression(node) ? false : "quit";
+                        return isExpressionNode(node) ? false : "quit";
                 }
             });
         }
@@ -15162,9 +15350,10 @@ namespace ts {
             return suggestion && symbolName(suggestion);
         }
 
-        function getSuggestionForNonexistentSymbol(location: Node, name: __String, meaning: SymbolFlags): string {
-            const result = resolveNameHelper(location, name, meaning, /*nameNotFoundMessage*/ undefined, name, /*isUse*/ false, (symbols, name, meaning) => {
-                // `name` from the callback === the outer `name`
+        function getSuggestionForNonexistentSymbol(location: Node, outerName: __String, meaning: SymbolFlags): string {
+            Debug.assert(outerName !== undefined, "outername should always be defined");
+            const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, (symbols, name, meaning) => {
+                Debug.assertEqual(outerName, name, "name should equal outerName");
                 const symbol = getSymbol(symbols, name, meaning);
                 // Sometimes the symbol is found when location is a return type of a function: `typeof x` and `x` is declared in the body of the function
                 // So the table *contains* `x` but `x` isn't actually in scope.
@@ -16489,21 +16678,9 @@ namespace ts {
          * but is a subtype of the Function interface, the call is an untyped function call.
          */
         function isUntypedFunctionCall(funcType: Type, apparentFuncType: Type, numCallSignatures: number, numConstructSignatures: number) {
-            if (isTypeAny(funcType)) {
-                return true;
-            }
-            if (isTypeAny(apparentFuncType) && funcType.flags & TypeFlags.TypeParameter) {
-                return true;
-            }
-            if (!numCallSignatures && !numConstructSignatures) {
-                // We exclude union types because we may have a union of function types that happen to have
-                // no common signatures.
-                if (funcType.flags & TypeFlags.Union) {
-                    return false;
-                }
-                return isTypeAssignableTo(funcType, globalFunctionType);
-            }
-            return false;
+            // We exclude union types because we may have a union of function types that happen to have no common signatures.
+            return isTypeAny(funcType) || isTypeAny(apparentFuncType) && funcType.flags & TypeFlags.TypeParameter ||
+                !numCallSignatures && !numConstructSignatures && !(funcType.flags & (TypeFlags.Union | TypeFlags.Never)) && isTypeAssignableTo(funcType, globalFunctionType);
         }
 
         function resolveNewExpression(node: NewExpression, candidatesOutArray: Signature[]): Signature {
@@ -16555,7 +16732,7 @@ namespace ts {
                 // only the class declaration node will have the Abstract flag set.
                 const valueDecl = expressionType.symbol && getClassLikeDeclarationOfSymbol(expressionType.symbol);
                 if (valueDecl && hasModifier(valueDecl, ModifierFlags.Abstract)) {
-                    error(node, Diagnostics.Cannot_create_an_instance_of_the_abstract_class_0, declarationNameToString(getNameOfDeclaration(valueDecl)));
+                    error(node, Diagnostics.Cannot_create_an_instance_of_an_abstract_class);
                     return resolveErrorCall(node);
                 }
 
@@ -16860,8 +17037,7 @@ namespace ts {
          * @returns On success, the expression's signature's return type. On failure, anyType.
          */
         function checkCallExpression(node: CallExpression | NewExpression): Type {
-            // Grammar checking; stop grammar-checking if checkGrammarTypeArguments return true
-            checkGrammarTypeArguments(node, node.typeArguments) || checkGrammarArguments(node.arguments);
+            if (!checkGrammarTypeArguments(node, node.typeArguments)) checkGrammarArguments(node.arguments);
 
             const signature = getResolvedSignature(node);
 
@@ -16908,7 +17084,7 @@ namespace ts {
 
         function checkImportCallExpression(node: ImportCall): Type {
             // Check grammar of dynamic import
-            checkGrammarArguments(node.arguments) || checkGrammarImportCallExpression(node);
+            if (!checkGrammarArguments(node.arguments)) checkGrammarImportCallExpression(node);
 
             if (node.arguments.length === 0) {
                 return createPromiseReturnType(node, anyType);
@@ -16958,7 +17134,7 @@ namespace ts {
             return type;
         }
 
-        function isCommonJsRequire(node: Node) {
+        function isCommonJsRequire(node: Node): boolean {
             if (!isRequireCall(node, /*checkArgumentIsStringLiteral*/ true)) {
                 return false;
             }
@@ -16982,7 +17158,7 @@ namespace ts {
             if (targetDeclarationKind !== SyntaxKind.Unknown) {
                 const decl = getDeclarationOfKind(resolvedRequire, targetDeclarationKind);
                 // function/variable declaration should be ambient
-                return isInAmbientContext(decl);
+                return !!(decl.flags & NodeFlags.Ambient);
             }
             return false;
         }
@@ -17959,14 +18135,6 @@ namespace ts {
             return (target.flags & TypeFlags.Nullable) !== 0 || isTypeComparableTo(source, target);
         }
 
-        function getBestChoiceType(type1: Type, type2: Type): Type {
-            const firstAssignableToSecond = isTypeAssignableTo(type1, type2);
-            const secondAssignableToFirst = isTypeAssignableTo(type2, type1);
-            return secondAssignableToFirst && !firstAssignableToSecond ? type1 :
-                firstAssignableToSecond && !secondAssignableToFirst ? type2 :
-                getUnionType([type1, type2], /*subtypeReduction*/ true);
-        }
-
         function checkBinaryExpression(node: BinaryExpression, checkMode?: CheckMode) {
             return checkBinaryLikeExpression(node.left, node.operatorToken, node.right, checkMode, node);
         }
@@ -18103,7 +18271,7 @@ namespace ts {
                         leftType;
                 case SyntaxKind.BarBarToken:
                     return getTypeFacts(leftType) & TypeFacts.Falsy ?
-                        getBestChoiceType(removeDefinitelyFalsyTypes(leftType), rightType) :
+                        getUnionType([removeDefinitelyFalsyTypes(leftType), rightType], /*subtypeReduction*/ true) :
                         leftType;
                 case SyntaxKind.EqualsToken:
                     checkAssignmentOperator(rightType);
@@ -18263,7 +18431,7 @@ namespace ts {
             checkExpression(node.condition);
             const type1 = checkExpression(node.whenTrue, checkMode);
             const type2 = checkExpression(node.whenFalse, checkMode);
-            return getBestChoiceType(type1, type2);
+            return getUnionType([type1, type2], /*subtypeReduction*/ true);
         }
 
         function checkTemplateExpression(node: TemplateExpression): Type {
@@ -18549,6 +18717,8 @@ namespace ts {
                     return checkJsxElement(<JsxElement>node);
                 case SyntaxKind.JsxSelfClosingElement:
                     return checkJsxSelfClosingElement(<JsxSelfClosingElement>node);
+                case SyntaxKind.JsxFragment:
+                    return checkJsxFragment(<JsxFragment>node);
                 case SyntaxKind.JsxAttributes:
                     return checkJsxAttributes(<JsxAttributes>node, checkMode);
                 case SyntaxKind.JsxOpeningElement:
@@ -18589,9 +18759,7 @@ namespace ts {
             // It is a SyntaxError if the Identifier "eval" or the Identifier "arguments" occurs as the
             // Identifier in a PropertySetParameterList of a PropertyAssignment that is contained in strict code
             // or if its FunctionBody is strict code(11.1.5).
-
-            // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
 
             checkVariableLikeDeclaration(node);
             const func = getContainingFunction(node);
@@ -18900,7 +19068,7 @@ namespace ts {
                         case "arguments":
                         case "prototype":
                             const message = Diagnostics.Static_property_0_conflicts_with_built_in_property_Function_0_of_constructor_function_1;
-                            const className = getNameOfSymbol(getSymbolOfNode(node));
+                            const className = getNameOfSymbolAsWritten(getSymbolOfNode(node));
                             error(memberNameNode, message, memberName, className);
                             break;
                     }
@@ -18981,14 +19149,13 @@ namespace ts {
 
         function checkPropertyDeclaration(node: PropertyDeclaration) {
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarProperty(node) || checkGrammarComputedPropertyName(node.name);
-
+            if (!checkGrammarDecoratorsAndModifiers(node) && !checkGrammarProperty(node)) checkGrammarComputedPropertyName(node.name);
             checkVariableLikeDeclaration(node);
         }
 
         function checkMethodDeclaration(node: MethodDeclaration) {
             // Grammar checking
-            checkGrammarMethod(node) || checkGrammarComputedPropertyName(node.name);
+            if (!checkGrammarMethod(node)) checkGrammarComputedPropertyName(node.name);
 
             // Grammar checking for modifiers is done inside the function checkGrammarFunctionLikeDeclaration
             checkFunctionOrMethodDeclaration(node);
@@ -19004,7 +19171,7 @@ namespace ts {
             // Grammar check on signature of constructor and modifier of the constructor is done in checkSignatureDeclaration function.
             checkSignatureDeclaration(node);
             // Grammar check for checking only related to constructorDeclaration
-            checkGrammarConstructorTypeParameters(node) || checkGrammarConstructorTypeAnnotation(node);
+            if (!checkGrammarConstructorTypeParameters(node)) checkGrammarConstructorTypeAnnotation(node);
 
             checkSourceElement(node.body);
             registerForUnusedIdentifiersCheck(node);
@@ -19101,12 +19268,12 @@ namespace ts {
         function checkAccessorDeclaration(node: AccessorDeclaration) {
             if (produceDiagnostics) {
                 // Grammar checking accessors
-                checkGrammarFunctionLikeDeclaration(node) || checkGrammarAccessor(node) || checkGrammarComputedPropertyName(node.name);
+                if (!checkGrammarFunctionLikeDeclaration(node) && !checkGrammarAccessor(node)) checkGrammarComputedPropertyName(node.name);
 
                 checkDecorators(node);
                 checkSignatureDeclaration(node);
                 if (node.kind === SyntaxKind.GetAccessor) {
-                    if (!isInAmbientContext(node) && nodeIsPresent(node.body) && (node.flags & NodeFlags.HasImplicitReturn)) {
+                    if (!(node.flags & NodeFlags.Ambient) && nodeIsPresent(node.body) && (node.flags & NodeFlags.HasImplicitReturn)) {
                         if (!(node.flags & NodeFlags.HasExplicitReturn)) {
                             error(node.name, Diagnostics.A_get_accessor_must_return_a_value);
                         }
@@ -19289,7 +19456,7 @@ namespace ts {
         }
 
         function isPrivateWithinAmbient(node: Node): boolean {
-            return hasModifier(node, ModifierFlags.Private) && isInAmbientContext(node);
+            return hasModifier(node, ModifierFlags.Private) && !!(node.flags & NodeFlags.Ambient);
         }
 
         function getEffectiveDeclarationFlags(n: Node, flagsToCheck: ModifierFlags): ModifierFlags {
@@ -19300,7 +19467,7 @@ namespace ts {
             if (n.parent.kind !== SyntaxKind.InterfaceDeclaration &&
                 n.parent.kind !== SyntaxKind.ClassDeclaration &&
                 n.parent.kind !== SyntaxKind.ClassExpression &&
-                isInAmbientContext(n)) {
+                n.flags & NodeFlags.Ambient) {
                 if (!(flags & ModifierFlags.Ambient)) {
                     // It is nested in an ambient context, which means it is automatically exported
                     flags |= ModifierFlags.Export;
@@ -19439,7 +19606,7 @@ namespace ts {
             let multipleConstructorImplementation = false;
             for (const current of declarations) {
                 const node = <FunctionLike>current;
-                const inAmbientContext = isInAmbientContext(node);
+                const inAmbientContext = node.flags & NodeFlags.Ambient;
                 const inAmbientContextOrInterface = node.parent.kind === SyntaxKind.InterfaceDeclaration || node.parent.kind === SyntaxKind.TypeLiteral || inAmbientContext;
                 if (inAmbientContextOrInterface) {
                     // check if declarations are consecutive only if they are non-ambient
@@ -20095,6 +20262,10 @@ namespace ts {
 
                     case SyntaxKind.Parameter:
                         markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(<ParameterDeclaration>node));
+                        const containingSignature = (node as ParameterDeclaration).parent;
+                        for (const parameter of containingSignature.parameters) {
+                            markDecoratorMedataDataTypeNodeAsReferenced(getParameterTypeNodeForDecoratorCheck(parameter));
+                        }
                         break;
                 }
             }
@@ -20280,21 +20451,20 @@ namespace ts {
                         case SyntaxKind.MethodSignature:
                         case SyntaxKind.CallSignature:
                         case SyntaxKind.ConstructSignature:
-                        case SyntaxKind.IndexSignature:
                         case SyntaxKind.FunctionType:
                         case SyntaxKind.ConstructorType:
-                            checkUnusedTypeParameters(<FunctionLikeDeclaration>node);
-                            break;
                         case SyntaxKind.TypeAliasDeclaration:
-                            checkUnusedTypeParameters(<TypeAliasDeclaration>node);
+                            checkUnusedTypeParameters(<MethodSignature | CallSignatureDeclaration | ConstructSignatureDeclaration | FunctionTypeNode | ConstructorTypeNode | TypeAliasDeclaration>node);
                             break;
+                        default:
+                            Debug.fail("Node should not have been registered for unused identifiers check");
                     }
                 }
             }
         }
 
         function checkUnusedLocalsAndParameters(node: Node): void {
-            if (node.parent.kind !== SyntaxKind.InterfaceDeclaration && noUnusedIdentifiers && !isInAmbientContext(node)) {
+            if (noUnusedIdentifiers && !(node.flags & NodeFlags.Ambient)) {
                 node.locals.forEach(local => {
                     if (!local.isReferenced) {
                         if (local.valueDeclaration && getRootDeclaration(local.valueDeclaration).kind === SyntaxKind.Parameter) {
@@ -20347,7 +20517,7 @@ namespace ts {
         }
 
         function checkUnusedClassMembers(node: ClassDeclaration | ClassExpression): void {
-            if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
+            if (compilerOptions.noUnusedLocals && !(node.flags & NodeFlags.Ambient)) {
                 if (node.members) {
                     for (const member of node.members) {
                         if (member.kind === SyntaxKind.MethodDeclaration || member.kind === SyntaxKind.PropertyDeclaration) {
@@ -20368,7 +20538,7 @@ namespace ts {
         }
 
         function checkUnusedTypeParameters(node: ClassDeclaration | ClassExpression | FunctionDeclaration | MethodDeclaration | FunctionExpression | ArrowFunction | ConstructorDeclaration | SignatureDeclaration | InterfaceDeclaration | TypeAliasDeclaration) {
-            if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
+            if (compilerOptions.noUnusedLocals && !(node.flags & NodeFlags.Ambient)) {
                 if (node.typeParameters) {
                     // Only report errors on the last declaration for the type parameter container;
                     // this ensures that all uses have been accounted for.
@@ -20387,7 +20557,7 @@ namespace ts {
         }
 
         function checkUnusedModuleMembers(node: ModuleDeclaration | SourceFile): void {
-            if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
+            if (compilerOptions.noUnusedLocals && !(node.flags & NodeFlags.Ambient)) {
                 node.locals.forEach(local => {
                     if (!local.isReferenced && !local.exportSymbol) {
                         for (const declaration of local.declarations) {
@@ -20420,7 +20590,7 @@ namespace ts {
 
         function checkCollisionWithArgumentsInGeneratedCode(node: SignatureDeclaration) {
             // no rest parameters \ declaration context \ overload - no codegen impact
-            if (!hasRestParameter(node) || isInAmbientContext(node) || nodeIsMissing((<FunctionLikeDeclaration>node).body)) {
+            if (!hasRestParameter(node) || node.flags & NodeFlags.Ambient || nodeIsMissing((<FunctionLikeDeclaration>node).body)) {
                 return;
             }
 
@@ -20446,7 +20616,7 @@ namespace ts {
                 return false;
             }
 
-            if (isInAmbientContext(node)) {
+            if (node.flags & NodeFlags.Ambient) {
                 // ambient context - no codegen impact
                 return false;
             }
@@ -20511,7 +20681,7 @@ namespace ts {
             // bubble up and find containing type
             const enclosingClass = getContainingClass(node);
             // if containing type was not found or it is ambient - exit (no codegen)
-            if (!enclosingClass || isInAmbientContext(enclosingClass)) {
+            if (!enclosingClass || enclosingClass.flags & NodeFlags.Ambient) {
                 return;
             }
 
@@ -20864,8 +21034,7 @@ namespace ts {
 
         function checkVariableStatement(node: VariableStatement) {
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarVariableDeclarationList(node.declarationList) || checkGrammarForDisallowedLetOrConstStatement(node);
-
+            if (!checkGrammarDecoratorsAndModifiers(node) && !checkGrammarVariableDeclarationList(node.declarationList)) checkGrammarForDisallowedLetOrConstStatement(node);
             forEach(node.declarationList.declarations, checkSourceElement);
         }
 
@@ -21373,7 +21542,7 @@ namespace ts {
 
         function checkBreakOrContinueStatement(node: BreakOrContinueStatement) {
             // Grammar checking
-            checkGrammarStatementInAmbientContext(node) || checkGrammarBreakOrContinueStatement(node);
+            if (!checkGrammarStatementInAmbientContext(node)) checkGrammarBreakOrContinueStatement(node);
 
             // TODO: Check that target label is valid
         }
@@ -21826,7 +21995,7 @@ namespace ts {
             checkClassForDuplicateDeclarations(node);
 
             // Only check for reserved static identifiers on non-ambient context.
-            if (!isInAmbientContext(node)) {
+            if (!(node.flags & NodeFlags.Ambient)) {
                 checkClassForStaticPropertyNameConflicts(node);
             }
 
@@ -22054,7 +22223,7 @@ namespace ts {
 
         function checkInterfaceDeclaration(node: InterfaceDeclaration) {
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarInterfaceDeclaration(node);
+            if (!checkGrammarDecoratorsAndModifiers(node)) checkGrammarInterfaceDeclaration(node);
 
             checkTypeParameters(node.typeParameters);
             if (produceDiagnostics) {
@@ -22096,7 +22265,7 @@ namespace ts {
 
         function checkTypeAliasDeclaration(node: TypeAliasDeclaration) {
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
 
             checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);
             checkTypeParameters(node.typeParameters);
@@ -22132,7 +22301,7 @@ namespace ts {
             }
             // In ambient enum declarations that specify no const modifier, enum member declarations that omit
             // a value are considered computed members (as opposed to having auto-incremented values).
-            if (isInAmbientContext(member.parent) && !isConst(member.parent)) {
+            if (member.parent.flags & NodeFlags.Ambient && !isConst(member.parent)) {
                 return undefined;
             }
             // If the member declaration specifies no value, the member is considered a constant enum member.
@@ -22165,7 +22334,7 @@ namespace ts {
             else if (isConstEnum) {
                 error(initializer, Diagnostics.In_const_enum_declarations_member_initializer_must_be_constant_expression);
             }
-            else if (isInAmbientContext(member.parent)) {
+            else if (member.parent.flags & NodeFlags.Ambient) {
                 error(initializer, Diagnostics.In_ambient_enum_declarations_member_initializer_must_be_constant_expression);
             }
             else {
@@ -22266,7 +22435,7 @@ namespace ts {
             }
 
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
 
             checkTypeNameIsReserved(node.name, Diagnostics.Enum_name_cannot_be_0);
             checkCollisionWithCapturedThisVariable(node, node.name);
@@ -22278,7 +22447,7 @@ namespace ts {
             computeEnumMemberValues(node);
 
             const enumIsConst = isConst(node);
-            if (compilerOptions.isolatedModules && enumIsConst && isInAmbientContext(node)) {
+            if (compilerOptions.isolatedModules && enumIsConst && node.flags & NodeFlags.Ambient) {
                 error(node.name, Diagnostics.Ambient_const_enums_are_not_allowed_when_the_isolatedModules_flag_is_provided);
             }
 
@@ -22330,7 +22499,7 @@ namespace ts {
             for (const declaration of declarations) {
                 if ((declaration.kind === SyntaxKind.ClassDeclaration ||
                     (declaration.kind === SyntaxKind.FunctionDeclaration && nodeIsPresent((<FunctionLikeDeclaration>declaration).body))) &&
-                    !isInAmbientContext(declaration)) {
+                    !(declaration.flags & NodeFlags.Ambient)) {
                     return declaration;
                 }
             }
@@ -22355,7 +22524,7 @@ namespace ts {
             if (produceDiagnostics) {
                 // Grammar checking
                 const isGlobalAugmentation = isGlobalScopeAugmentation(node);
-                const inAmbientContext = isInAmbientContext(node);
+                const inAmbientContext = node.flags & NodeFlags.Ambient;
                 if (isGlobalAugmentation && !inAmbientContext) {
                     error(node.name, Diagnostics.Augmentations_for_the_global_scope_should_have_declare_modifier_unless_they_appear_in_already_ambient_context);
                 }
@@ -22369,7 +22538,7 @@ namespace ts {
                     return;
                 }
 
-                if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node)) {
+                if (!checkGrammarDecoratorsAndModifiers(node)) {
                     if (!inAmbientContext && node.name.kind === SyntaxKind.StringLiteral) {
                         grammarErrorOnNode(node.name, Diagnostics.Only_ambient_modules_can_use_quoted_names);
                     }
@@ -22574,7 +22743,7 @@ namespace ts {
                 if (compilerOptions.isolatedModules
                     && node.kind === SyntaxKind.ExportSpecifier
                     && !(target.flags & SymbolFlags.Value)
-                    && !isInAmbientContext(node)) {
+                    && !(node.flags & NodeFlags.Ambient)) {
                     error(node, Diagnostics.Cannot_re_export_a_type_when_the_isolatedModules_flag_is_provided);
                 }
             }
@@ -22592,7 +22761,7 @@ namespace ts {
                 // If we hit an import declaration in an illegal context, just bail out to avoid cascading errors.
                 return;
             }
-            if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node) && hasModifiers(node)) {
+            if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
                 grammarErrorOnFirstToken(node, Diagnostics.An_import_declaration_cannot_have_modifiers);
             }
             if (checkExternalImportOrExportDeclaration(node)) {
@@ -22619,13 +22788,13 @@ namespace ts {
                 return;
             }
 
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
             if (isInternalModuleImportEqualsDeclaration(node) || checkExternalImportOrExportDeclaration(node)) {
                 checkImportBinding(node);
                 if (hasModifier(node, ModifierFlags.Export)) {
                     markExportAsReferenced(node);
                 }
-                if (isInternalModuleImportEqualsDeclaration(node)) {
+                if (node.moduleReference.kind !== SyntaxKind.ExternalModuleReference) {
                     const target = resolveAlias(getSymbolOfNode(node));
                     if (target !== unknownSymbol) {
                         if (target.flags & SymbolFlags.Value) {
@@ -22641,7 +22810,7 @@ namespace ts {
                     }
                 }
                 else {
-                    if (modulekind >= ModuleKind.ES2015 && !isInAmbientContext(node)) {
+                    if (modulekind >= ModuleKind.ES2015 && !(node.flags & NodeFlags.Ambient)) {
                         // Import equals declaration is deprecated in es6 or above
                         grammarErrorOnNode(node, Diagnostics.Import_assignment_cannot_be_used_when_targeting_ECMAScript_modules_Consider_using_import_Asterisk_as_ns_from_mod_import_a_from_mod_import_d_from_mod_or_another_module_format_instead);
                     }
@@ -22655,7 +22824,7 @@ namespace ts {
                 return;
             }
 
-            if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node) && hasModifiers(node)) {
+            if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
                 grammarErrorOnFirstToken(node, Diagnostics.An_export_declaration_cannot_have_modifiers);
             }
 
@@ -22667,7 +22836,7 @@ namespace ts {
 
                     const inAmbientExternalModule = node.parent.kind === SyntaxKind.ModuleBlock && isAmbientModule(node.parent.parent);
                     const inAmbientNamespaceDeclaration = !inAmbientExternalModule && node.parent.kind === SyntaxKind.ModuleBlock &&
-                        !node.moduleSpecifier && isInAmbientContext(node);
+                        !node.moduleSpecifier && node.flags & NodeFlags.Ambient;
                     if (node.parent.kind !== SyntaxKind.SourceFile && !inAmbientExternalModule && !inAmbientNamespaceDeclaration) {
                         error(node, Diagnostics.Export_declarations_are_not_permitted_in_a_namespace);
                     }
@@ -22728,7 +22897,7 @@ namespace ts {
                 return;
             }
             // Grammar checking
-            if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node) && hasModifiers(node)) {
+            if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
                 grammarErrorOnFirstToken(node, Diagnostics.An_export_assignment_cannot_have_modifiers);
             }
             if (node.expression.kind === SyntaxKind.Identifier) {
@@ -22740,11 +22909,11 @@ namespace ts {
 
             checkExternalModuleExports(container);
 
-            if (isInAmbientContext(node) && !isEntityNameExpression(node.expression)) {
+            if ((node.flags & NodeFlags.Ambient) && !isEntityNameExpression(node.expression)) {
                 grammarErrorOnNode(node.expression, Diagnostics.The_expression_of_an_export_assignment_must_be_an_identifier_or_qualified_name_in_an_ambient_context);
             }
 
-            if (node.isExportEquals && !isInAmbientContext(node)) {
+            if (node.isExportEquals && !(node.flags & NodeFlags.Ambient)) {
                 if (modulekind >= ModuleKind.ES2015) {
                     // export assignment is not supported in es6 modules
                     grammarErrorOnNode(node, Diagnostics.Export_assignment_cannot_be_used_when_targeting_ECMAScript_modules_Consider_using_export_default_or_another_module_format_instead);
@@ -22773,29 +22942,31 @@ namespace ts {
                 }
                 // Checks for export * conflicts
                 const exports = getExportsOfModule(moduleSymbol);
-                exports && exports.forEach(({ declarations, flags }, id) => {
-                    if (id === "__export") {
-                        return;
-                    }
-                    // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries.
-                    // (TS Exceptions: namespaces, function overloads, enums, and interfaces)
-                    if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
-                        return;
-                    }
-                    const exportedDeclarationsCount = countWhere(declarations, isNotOverloadAndNotAccessor);
-                    if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
-                        // it is legal to merge type alias with other values
-                        // so count should be either 1 (just type alias) or 2 (type alias + merged value)
-                        return;
-                    }
-                    if (exportedDeclarationsCount > 1) {
-                        for (const declaration of declarations) {
-                            if (isNotOverload(declaration)) {
-                                diagnostics.add(createDiagnosticForNode(declaration, Diagnostics.Cannot_redeclare_exported_variable_0, unescapeLeadingUnderscores(id)));
+                if (exports) {
+                    exports.forEach(({ declarations, flags }, id) => {
+                        if (id === "__export") {
+                            return;
+                        }
+                        // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries.
+                        // (TS Exceptions: namespaces, function overloads, enums, and interfaces)
+                        if (flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) {
+                            return;
+                        }
+                        const exportedDeclarationsCount = countWhere(declarations, isNotOverloadAndNotAccessor);
+                        if (flags & SymbolFlags.TypeAlias && exportedDeclarationsCount <= 2) {
+                            // it is legal to merge type alias with other values
+                            // so count should be either 1 (just type alias) or 2 (type alias + merged value)
+                            return;
+                        }
+                        if (exportedDeclarationsCount > 1) {
+                            for (const declaration of declarations) {
+                                if (isNotOverload(declaration)) {
+                                    diagnostics.add(createDiagnosticForNode(declaration, Diagnostics.Cannot_redeclare_exported_variable_0, unescapeLeadingUnderscores(id)));
+                                }
                             }
                         }
-                    }
-                });
+                    });
+                }
                 links.exportsChecked = true;
             }
         }
@@ -23035,7 +23206,7 @@ namespace ts {
 
                 checkDeferredNodes();
 
-                if (isExternalModule(node)) {
+                if (isExternalOrCommonJsModule(node)) {
                     registerForUnusedIdentifiersCheck(node);
                 }
 
@@ -23263,9 +23434,9 @@ namespace ts {
             return result;
         }
 
-        function isNodeWithinConstructor(node: Node, classDeclaration: ClassLikeDeclaration) {
+        function isNodeWithinConstructorOfClass(node: Node, classDeclaration: ClassLikeDeclaration) {
             return findAncestor(node, element => {
-                if (isConstructorDeclaration(element) && nodeIsPresent(element.body)) {
+                if (isConstructorDeclaration(element) && nodeIsPresent(element.body) && element.parent === classDeclaration) {
                     return true;
                 }
                 else if (element === classDeclaration || isFunctionLikeDeclaration(element)) {
@@ -23376,7 +23547,7 @@ namespace ts {
                 return typeParameter && typeParameter.symbol;
             }
 
-            if (isPartOfExpression(entityName)) {
+            if (isExpressionNode(entityName)) {
                 if (nodeIsMissing(entityName)) {
                     // Missing entity name.
                     return undefined;
@@ -23508,6 +23679,8 @@ namespace ts {
                     return objectType && getPropertyOfType(objectType, escapeLeadingUnderscores((node as StringLiteral | NumericLiteral).text));
 
                 case SyntaxKind.DefaultKeyword:
+                case SyntaxKind.FunctionKeyword:
+                case SyntaxKind.EqualsGreaterThanToken:
                     return getSymbolOfNode(node.parent);
 
                 default:
@@ -23550,7 +23723,7 @@ namespace ts {
                 return typeFromTypeNode;
             }
 
-            if (isPartOfExpression(node)) {
+            if (isExpressionNode(node)) {
                 return getRegularTypeOfExpression(<Expression>node);
             }
 
@@ -24376,7 +24549,7 @@ namespace ts {
         function checkExternalEmitHelpers(location: Node, helpers: ExternalEmitHelpers) {
             if ((requestedExternalEmitHelpers & helpers) !== helpers && compilerOptions.importHelpers) {
                 const sourceFile = getSourceFileOfNode(location);
-                if (isEffectiveExternalModule(sourceFile, compilerOptions) && !isInAmbientContext(location)) {
+                if (isEffectiveExternalModule(sourceFile, compilerOptions) && !(location.flags & NodeFlags.Ambient)) {
                     const helpersModule = resolveHelpersModule(sourceFile, location);
                     if (helpersModule !== unknownSymbol) {
                         const uncheckedHelpers = helpers & ~requestedExternalEmitHelpers;
@@ -24426,12 +24599,16 @@ namespace ts {
         }
 
         // GRAMMAR CHECKING
+        function checkGrammarDecoratorsAndModifiers(node: Node): boolean {
+            return checkGrammarDecorators(node) || checkGrammarModifiers(node);
+        }
+
         function checkGrammarDecorators(node: Node): boolean {
             if (!node.decorators) {
                 return false;
             }
             if (!nodeCanBeDecorated(node)) {
-                if (node.kind === SyntaxKind.MethodDeclaration && !ts.nodeIsPresent((<MethodDeclaration>node).body)) {
+                if (node.kind === SyntaxKind.MethodDeclaration && !nodeIsPresent((<MethodDeclaration>node).body)) {
                     return grammarErrorOnFirstToken(node, Diagnostics.A_decorator_can_only_decorate_a_method_implementation_not_an_overload);
                 }
                 else {
@@ -24578,7 +24755,7 @@ namespace ts {
                         else if (node.kind === SyntaxKind.Parameter) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_parameter, "declare");
                         }
-                        else if (isInAmbientContext(node.parent) && node.parent.kind === SyntaxKind.ModuleBlock) {
+                        else if ((node.parent.flags & NodeFlags.Ambient) && node.parent.kind === SyntaxKind.ModuleBlock) {
                             return grammarErrorOnNode(modifier, Diagnostics.A_declare_modifier_cannot_be_used_in_an_already_ambient_context);
                         }
                         flags |= ModifierFlags.Ambient;
@@ -24614,7 +24791,7 @@ namespace ts {
                         if (flags & ModifierFlags.Async) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_already_seen, "async");
                         }
-                        else if (flags & ModifierFlags.Ambient || isInAmbientContext(node.parent)) {
+                        else if (flags & ModifierFlags.Ambient || node.parent.flags & NodeFlags.Ambient) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_in_an_ambient_context, "async");
                         }
                         else if (node.kind === SyntaxKind.Parameter) {
@@ -24781,7 +24958,7 @@ namespace ts {
         function checkGrammarFunctionLikeDeclaration(node: FunctionLikeDeclaration): boolean {
             // Prevent cascading error by short-circuit
             const file = getSourceFileOfNode(node);
-            return checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarTypeParameterList(node.typeParameters, file) ||
+            return checkGrammarDecoratorsAndModifiers(node) || checkGrammarTypeParameterList(node.typeParameters, file) ||
                 checkGrammarParameterList(node.parameters) || checkGrammarArrowFunction(node, file);
         }
 
@@ -24837,7 +25014,7 @@ namespace ts {
 
         function checkGrammarIndexSignature(node: SignatureDeclaration) {
             // Prevent cascading error by short-circuit
-            return checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarIndexSignatureParameters(node);
+            return checkGrammarDecoratorsAndModifiers(node) || checkGrammarIndexSignatureParameters(node);
         }
 
         function checkGrammarForAtLeastOneTypeArgument(node: Node, typeArguments: NodeArray<TypeNode>): boolean {
@@ -24888,7 +25065,7 @@ namespace ts {
             let seenExtendsClause = false;
             let seenImplementsClause = false;
 
-            if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node) && node.heritageClauses) {
+            if (!checkGrammarDecoratorsAndModifiers(node) && node.heritageClauses) {
                 for (const heritageClause of node.heritageClauses) {
                     if (heritageClause.token === SyntaxKind.ExtendsKeyword) {
                         if (seenExtendsClause) {
@@ -24962,7 +25139,7 @@ namespace ts {
                     node.kind === SyntaxKind.FunctionDeclaration ||
                     node.kind === SyntaxKind.FunctionExpression ||
                     node.kind === SyntaxKind.MethodDeclaration);
-                if (isInAmbientContext(node)) {
+                if (node.flags & NodeFlags.Ambient) {
                     return grammarErrorOnNode(node.asteriskToken, Diagnostics.Generators_are_not_allowed_in_an_ambient_context);
                 }
                 if (!node.body) {
@@ -24978,11 +25155,13 @@ namespace ts {
         }
 
         function checkGrammarObjectLiteralExpression(node: ObjectLiteralExpression, inDestructuring: boolean) {
-            const seen = createUnderscoreEscapedMap<SymbolFlags>();
-            const Property = 1;
-            const GetAccessor = 2;
-            const SetAccessor = 4;
-            const GetOrSetAccessor = GetAccessor | SetAccessor;
+            const enum Flags {
+                Property = 1,
+                GetAccessor = 2,
+                SetAccessor = 4,
+                GetOrSetAccessor = GetAccessor | SetAccessor,
+            }
+            const seen = createUnderscoreEscapedMap<Flags>();
 
             for (const prop of node.properties) {
                 if (prop.kind === SyntaxKind.SpreadAssignment) {
@@ -25017,26 +25196,27 @@ namespace ts {
                 //    c.IsAccessorDescriptor(previous) is true and IsDataDescriptor(propId.descriptor) is true.
                 //    d.IsAccessorDescriptor(previous) is true and IsAccessorDescriptor(propId.descriptor) is true
                 // and either both previous and propId.descriptor have[[Get]] fields or both previous and propId.descriptor have[[Set]] fields
-                let currentKind: number;
-                if (prop.kind === SyntaxKind.PropertyAssignment || prop.kind === SyntaxKind.ShorthandPropertyAssignment) {
-                    // Grammar checking for computedPropertyName and shorthandPropertyAssignment
-                    checkGrammarForInvalidQuestionMark((<PropertyAssignment>prop).questionToken, Diagnostics.An_object_member_cannot_be_declared_optional);
-                    if (name.kind === SyntaxKind.NumericLiteral) {
-                        checkGrammarNumericLiteral(<NumericLiteral>name);
-                    }
-                    currentKind = Property;
-                }
-                else if (prop.kind === SyntaxKind.MethodDeclaration) {
-                    currentKind = Property;
-                }
-                else if (prop.kind === SyntaxKind.GetAccessor) {
-                    currentKind = GetAccessor;
-                }
-                else if (prop.kind === SyntaxKind.SetAccessor) {
-                    currentKind = SetAccessor;
-                }
-                else {
-                    Debug.assertNever(prop, "Unexpected syntax kind:" + (<Node>prop).kind);
+                let currentKind: Flags;
+                switch (prop.kind) {
+                    case SyntaxKind.PropertyAssignment:
+                    case SyntaxKind.ShorthandPropertyAssignment:
+                        // Grammar checking for computedPropertyName and shorthandPropertyAssignment
+                        checkGrammarForInvalidQuestionMark((<PropertyAssignment>prop).questionToken, Diagnostics.An_object_member_cannot_be_declared_optional);
+                        if (name.kind === SyntaxKind.NumericLiteral) {
+                            checkGrammarNumericLiteral(<NumericLiteral>name);
+                        }
+                        // falls through
+                    case SyntaxKind.MethodDeclaration:
+                        currentKind = Flags.Property;
+                        break;
+                    case SyntaxKind.GetAccessor:
+                        currentKind = Flags.GetAccessor;
+                        break;
+                    case SyntaxKind.SetAccessor:
+                        currentKind = Flags.SetAccessor;
+                        break;
+                    default:
+                        Debug.assertNever(prop, "Unexpected syntax kind:" + (<Node>prop).kind);
                 }
 
                 const effectiveName = getPropertyNameForPropertyNameNode(name);
@@ -25049,11 +25229,11 @@ namespace ts {
                     seen.set(effectiveName, currentKind);
                 }
                 else {
-                    if (currentKind === Property && existingKind === Property) {
+                    if (currentKind === Flags.Property && existingKind === Flags.Property) {
                         grammarErrorOnNode(name, Diagnostics.Duplicate_identifier_0, getTextOfNode(name));
                     }
-                    else if ((currentKind & GetOrSetAccessor) && (existingKind & GetOrSetAccessor)) {
-                        if (existingKind !== GetOrSetAccessor && currentKind !== existingKind) {
+                    else if ((currentKind & Flags.GetOrSetAccessor) && (existingKind & Flags.GetOrSetAccessor)) {
+                        if (existingKind !== Flags.GetOrSetAccessor && currentKind !== existingKind) {
                             seen.set(effectiveName, currentKind | existingKind);
                         }
                         else {
@@ -25149,7 +25329,7 @@ namespace ts {
             if (languageVersion < ScriptTarget.ES5) {
                 return grammarErrorOnNode(accessor.name, Diagnostics.Accessors_are_only_available_when_targeting_ECMAScript_5_and_higher);
             }
-            else if (isInAmbientContext(accessor)) {
+            else if (accessor.flags & NodeFlags.Ambient) {
                 return grammarErrorOnNode(accessor.name, Diagnostics.An_accessor_cannot_be_declared_in_an_ambient_context);
             }
             else if (accessor.body === undefined && !hasModifier(accessor, ModifierFlags.Abstract)) {
@@ -25228,7 +25408,7 @@ namespace ts {
                 // However, property declarations disallow computed names in general,
                 // and accessors are not allowed in ambient contexts in general,
                 // so this error only really matters for methods.
-                if (isInAmbientContext(node)) {
+                if (node.flags & NodeFlags.Ambient) {
                     return checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_an_ambient_context_must_directly_refer_to_a_built_in_symbol);
                 }
                 else if (!node.body) {
@@ -25323,7 +25503,7 @@ namespace ts {
 
         function checkGrammarVariableDeclaration(node: VariableDeclaration) {
             if (node.parent.parent.kind !== SyntaxKind.ForInStatement && node.parent.parent.kind !== SyntaxKind.ForOfStatement) {
-                if (isInAmbientContext(node)) {
+                if (node.flags & NodeFlags.Ambient) {
                     if (node.initializer) {
                         if (isConst(node) && !node.type) {
                             if (!isStringOrNumberLiteralExpression(node.initializer)) {
@@ -25353,7 +25533,7 @@ namespace ts {
             }
 
             if (compilerOptions.module !== ModuleKind.ES2015 && compilerOptions.module !== ModuleKind.ESNext && compilerOptions.module !== ModuleKind.System && !compilerOptions.noEmit &&
-                !isInAmbientContext(node.parent.parent) && hasModifier(node.parent.parent, ModifierFlags.Export)) {
+                !(node.parent.parent.flags & NodeFlags.Ambient) && hasModifier(node.parent.parent, ModifierFlags.Export)) {
                 checkESModuleMarker(node.name);
             }
 
@@ -25512,7 +25692,7 @@ namespace ts {
                 }
             }
 
-            if (isInAmbientContext(node) && node.initializer) {
+            if (node.flags & NodeFlags.Ambient && node.initializer) {
                 return grammarErrorOnFirstToken(node.initializer, Diagnostics.Initializers_are_not_allowed_in_ambient_contexts);
             }
         }
@@ -25555,11 +25735,11 @@ namespace ts {
         }
 
         function checkGrammarSourceFile(node: SourceFile): boolean {
-            return isInAmbientContext(node) && checkGrammarTopLevelElementsForRequiredDeclareModifier(node);
+            return !!(node.flags & NodeFlags.Ambient) && checkGrammarTopLevelElementsForRequiredDeclareModifier(node);
         }
 
         function checkGrammarStatementInAmbientContext(node: Node): boolean {
-            if (isInAmbientContext(node)) {
+            if (node.flags & NodeFlags.Ambient) {
                 // An accessors is already reported about the ambient context
                 if (isAccessor(node.parent)) {
                     return getNodeLinks(node).hasReportedStatementInAmbientContext = true;
@@ -25681,4 +25861,17 @@ namespace ts {
                 return false;
         }
     }
+
+    namespace JsxNames {
+        // tslint:disable variable-name
+        export const JSX = "JSX" as __String;
+        export const IntrinsicElements = "IntrinsicElements" as __String;
+        export const ElementClass = "ElementClass" as __String;
+        export const ElementAttributesPropertyNameContainer = "ElementAttributesProperty" as __String;
+        export const ElementChildrenAttributeNameContainer = "ElementChildrenAttribute" as __String;
+        export const Element = "Element" as __String;
+        export const IntrinsicAttributes = "IntrinsicAttributes" as __String;
+        export const IntrinsicClassAttributes = "IntrinsicClassAttributes" as __String;
+        // tslint:enable variable-name
+    }
 }
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index f050c4a5d16..43ea77c8020 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -76,13 +76,13 @@ namespace ts {
             name: "target",
             shortName: "t",
             type: createMapFromTemplate({
-                "es3": ScriptTarget.ES3,
-                "es5": ScriptTarget.ES5,
-                "es6": ScriptTarget.ES2015,
-                "es2015": ScriptTarget.ES2015,
-                "es2016": ScriptTarget.ES2016,
-                "es2017": ScriptTarget.ES2017,
-                "esnext": ScriptTarget.ESNext,
+                es3: ScriptTarget.ES3,
+                es5: ScriptTarget.ES5,
+                es6: ScriptTarget.ES2015,
+                es2015: ScriptTarget.ES2015,
+                es2016: ScriptTarget.ES2016,
+                es2017: ScriptTarget.ES2017,
+                esnext: ScriptTarget.ESNext,
             }),
             paramType: Diagnostics.VERSION,
             showInSimplifiedHelpView: true,
@@ -93,14 +93,14 @@ namespace ts {
             name: "module",
             shortName: "m",
             type: createMapFromTemplate({
-                "none": ModuleKind.None,
-                "commonjs": ModuleKind.CommonJS,
-                "amd": ModuleKind.AMD,
-                "system": ModuleKind.System,
-                "umd": ModuleKind.UMD,
-                "es6": ModuleKind.ES2015,
-                "es2015": ModuleKind.ES2015,
-                "esnext": ModuleKind.ESNext
+                none: ModuleKind.None,
+                commonjs: ModuleKind.CommonJS,
+                amd: ModuleKind.AMD,
+                system: ModuleKind.System,
+                umd: ModuleKind.UMD,
+                es6: ModuleKind.ES2015,
+                es2015: ModuleKind.ES2015,
+                esnext: ModuleKind.ESNext
             }),
             paramType: Diagnostics.KIND,
             showInSimplifiedHelpView: true,
@@ -141,6 +141,7 @@ namespace ts {
                     "es2017.sharedmemory": "lib.es2017.sharedmemory.d.ts",
                     "es2017.string": "lib.es2017.string.d.ts",
                     "es2017.intl": "lib.es2017.intl.d.ts",
+                    "es2017.typedarrays": "lib.es2017.typedarrays.d.ts",
                     "esnext.asynciterable": "lib.esnext.asynciterable.d.ts",
                 }),
             },
@@ -325,8 +326,8 @@ namespace ts {
         {
             name: "moduleResolution",
             type: createMapFromTemplate({
-                "node": ModuleResolutionKind.NodeJs,
-                "classic": ModuleResolutionKind.Classic,
+                node: ModuleResolutionKind.NodeJs,
+                classic: ModuleResolutionKind.Classic,
             }),
             paramType: Diagnostics.STRATEGY,
             category: Diagnostics.Module_Resolution_Options,
@@ -521,8 +522,8 @@ namespace ts {
         {
             name: "newLine",
             type: createMapFromTemplate({
-                "crlf": NewLineKind.CarriageReturnLineFeed,
-                "lf": NewLineKind.LineFeed
+                crlf: NewLineKind.CarriageReturnLineFeed,
+                lf: NewLineKind.LineFeed
             }),
             paramType: Diagnostics.NEWLINE,
             category: Diagnostics.Advanced_Options,
@@ -1138,6 +1139,13 @@ namespace ts {
                     reportInvalidOptionValue(option && option.type !== "number");
                     return Number((<NumericLiteral>valueExpression).text);
 
+                case SyntaxKind.PrefixUnaryExpression:
+                    if ((<PrefixUnaryExpression>valueExpression).operator !== SyntaxKind.MinusToken || (<PrefixUnaryExpression>valueExpression).operand.kind !== SyntaxKind.NumericLiteral) {
+                        break; // not valid JSON syntax
+                    }
+                    reportInvalidOptionValue(option && option.type !== "number");
+                    return -Number((<NumericLiteral>(<PrefixUnaryExpression>valueExpression).operand).text);
+
                 case SyntaxKind.ObjectLiteralExpression:
                     reportInvalidOptionValue(option && option.type !== "object");
                     const objectLiteralExpression = <ObjectLiteralExpression>valueExpression;
diff --git a/src/compiler/comments.ts b/src/compiler/comments.ts
index 025a4f36d26..1fec1e9562f 100644
--- a/src/compiler/comments.ts
+++ b/src/compiler/comments.ts
@@ -260,7 +260,7 @@ namespace ts {
             }
         }
 
-        function emitLeadingComment(commentPos: number, commentEnd: number, _kind: SyntaxKind, hasTrailingNewLine: boolean, rangePos: number) {
+        function emitLeadingComment(commentPos: number, commentEnd: number, kind: SyntaxKind, hasTrailingNewLine: boolean, rangePos: number) {
             if (!hasWrittenComment) {
                 emitNewLineBeforeLeadingCommentOfPosition(currentLineMap, writer, rangePos, commentPos);
                 hasWrittenComment = true;
@@ -274,7 +274,7 @@ namespace ts {
             if (hasTrailingNewLine) {
                 writer.writeLine();
             }
-            else {
+            else if (kind === SyntaxKind.MultiLineCommentTrivia) {
                 writer.write(" ");
             }
         }
diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 657f362067b..f3dd99ee5bf 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -20,12 +20,6 @@ namespace ts {
 
 /* @internal */
 namespace ts {
-
-    // More efficient to create a collator once and use its `compare` than to call `a.localeCompare(b)` many times.
-    export const collator: { compare(a: string, b: string): number } = typeof Intl === "object" && typeof Intl.Collator === "function" ? new Intl.Collator(/*locales*/ undefined, { usage: "sort", sensitivity: "accent" }) : undefined;
-    // Intl is missing in Safari, and node 0.10 treats "a" as greater than "B".
-    export const localeCompareIsCorrect = ts.collator && ts.collator.compare("a", "B") < 0;
-
     /** Create a MapLike with good performance. */
     function createDictionaryObject<T>(): MapLike<T> {
         const map = Object.create(/*prototype*/ null); // tslint:disable-line:no-null-keyword
@@ -76,7 +70,7 @@ namespace ts {
     // The global Map object. This may not be available, so we must test for it.
     declare const Map: { new <T>(): Map<T> } | undefined;
     // Internet Explorer's Map doesn't support iteration, so don't use it.
-    // tslint:disable-next-line:no-in-operator
+    // tslint:disable-next-line no-in-operator variable-name
     const MapCtr = typeof Map !== "undefined" && "entries" in Map.prototype ? Map : shimMap();
 
     // Keep the class inside a function so it doesn't get compiled if it's not used.
@@ -165,12 +159,6 @@ namespace ts {
         return <Path>getCanonicalFileName(nonCanonicalizedPath);
     }
 
-    export const enum Comparison {
-        LessThan = -1,
-        EqualTo = 0,
-        GreaterThan = 1
-    }
-
     export function length(array: ReadonlyArray<any>) {
         return array ? array.length : 0;
     }
@@ -307,10 +295,10 @@ namespace ts {
         Debug.fail();
     }
 
-    export function contains<T>(array: ReadonlyArray<T>, value: T): boolean {
+    export function contains<T>(array: ReadonlyArray<T>, value: T, equalityComparer: EqualityComparer<T> = equateValues): boolean {
         if (array) {
             for (const v of array) {
-                if (v === value) {
+                if (equalityComparer(v, value)) {
                     return true;
                 }
             }
@@ -655,24 +643,85 @@ namespace ts {
         return [...array1, ...array2];
     }
 
-    // TODO: fixme (N^2) - add optional comparer so collection can be sorted before deduplication.
-    export function deduplicate<T>(array: ReadonlyArray<T>, areEqual?: (a: T, b: T) => boolean): T[] {
-        let result: T[];
-        if (array) {
-            result = [];
-            loop: for (const item of array) {
-                for (const res of result) {
-                    if (areEqual ? areEqual(res, item) : res === item) {
-                        continue loop;
-                    }
-                }
-                result.push(item);
+    function deduplicateRelational<T>(array: ReadonlyArray<T>, equalityComparer: EqualityComparer<T>, comparer: Comparer<T>) {
+        // Perform a stable sort of the array. This ensures the first entry in a list of
+        // duplicates remains the first entry in the result.
+        const indices = array.map((_, i) => i);
+        stableSortIndices(array, indices, comparer);
+
+        let last = array[indices[0]];
+        const deduplicated: number[] = [indices[0]];
+        for (let i = 1; i < indices.length; i++) {
+            const index = indices[i];
+            const item = array[index];
+            if (!equalityComparer(last, item)) {
+                deduplicated.push(index);
+                last = item;
             }
         }
+
+        // restore original order
+        deduplicated.sort();
+        return deduplicated.map(i => array[i]);
+    }
+
+    function deduplicateEquality<T>(array: ReadonlyArray<T>, equalityComparer: EqualityComparer<T>) {
+        const result: T[] = [];
+        for (const item of array) {
+            pushIfUnique(result, item, equalityComparer);
+        }
         return result;
     }
 
-    export function arrayIsEqualTo<T>(array1: ReadonlyArray<T>, array2: ReadonlyArray<T>, equaler?: (a: T, b: T) => boolean): boolean {
+    /**
+     * Deduplicates an unsorted array.
+     * @param equalityComparer An optional `EqualityComparer` used to determine if two values are duplicates.
+     * @param comparer An optional `Comparer` used to sort entries before comparison, though the
+     * result will remain in the original order in `array`.
+     */
+    export function deduplicate<T>(array: ReadonlyArray<T>, equalityComparer: EqualityComparer<T>, comparer?: Comparer<T>): T[] {
+        return !array ? undefined :
+            array.length === 0 ? [] :
+            array.length === 1 ? array.slice() :
+            comparer ? deduplicateRelational(array, equalityComparer, comparer) :
+            deduplicateEquality(array, equalityComparer);
+    }
+
+    /**
+     * Deduplicates an array that has already been sorted.
+     */
+    function deduplicateSorted<T>(array: ReadonlyArray<T>, comparer: EqualityComparer<T> | Comparer<T>) {
+        if (!array) return undefined;
+        if (array.length === 0) return [];
+
+        let last = array[0];
+        const deduplicated: T[] = [last];
+        for (let i = 1; i < array.length; i++) {
+            const next = array[i];
+            switch (comparer(next, last)) {
+                // equality comparison
+                case true:
+
+                // relational comparison
+                case Comparison.EqualTo:
+                    continue;
+
+                case Comparison.LessThan:
+                    // If `array` is sorted, `next` should **never** be less than `last`.
+                    return Debug.fail("Array is unsorted.");
+            }
+
+            deduplicated.push(last = next);
+        }
+
+        return deduplicated;
+    }
+
+    export function sortAndDeduplicate<T>(array: ReadonlyArray<T>, comparer: Comparer<T>, equalityComparer?: EqualityComparer<T>) {
+        return deduplicateSorted(sort(array, comparer), equalityComparer || comparer);
+    }
+
+    export function arrayIsEqualTo<T>(array1: ReadonlyArray<T>, array2: ReadonlyArray<T>, equalityComparer: (a: T, b: T) => boolean = equateValues): boolean {
         if (!array1 || !array2) {
             return array1 === array2;
         }
@@ -682,8 +731,7 @@ namespace ts {
         }
 
         for (let i = 0; i < array1.length; i++) {
-            const equals = equaler ? equaler(array1[i], array2[i]) : array1[i] === array2[i];
-            if (!equals) {
+            if (!equalityComparer(array1[i], array2[i])) {
                 return false;
             }
         }
@@ -734,22 +782,44 @@ namespace ts {
     }
 
     /**
-     * Gets the relative complement of `arrayA` with respect to `b`, returning the elements that
+     * Gets the relative complement of `arrayA` with respect to `arrayB`, returning the elements that
      * are not present in `arrayA` but are present in `arrayB`. Assumes both arrays are sorted
      * based on the provided comparer.
      */
-    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: Comparer<T> = compareValues, offsetA = 0, offsetB = 0): T[] | undefined {
+    export function relativeComplement<T>(arrayA: T[] | undefined, arrayB: T[] | undefined, comparer: Comparer<T>): T[] | undefined {
         if (!arrayB || !arrayA || arrayB.length === 0 || arrayA.length === 0) return arrayB;
         const result: T[] = [];
-        outer: for (; offsetB < arrayB.length; offsetB++) {
-            inner: for (; offsetA < arrayA.length; offsetA++) {
+        loopB: for (let offsetA = 0, offsetB = 0; offsetB < arrayB.length; offsetB++) {
+            if (offsetB > 0) {
+                // Ensure `arrayB` is properly sorted.
+                Debug.assertGreaterThanOrEqual(comparer(arrayB[offsetB], arrayB[offsetB - 1]), Comparison.EqualTo);
+            }
+
+            loopA: for (const startA = offsetA; offsetA < arrayA.length; offsetA++) {
+                if (offsetA > startA) {
+                    // Ensure `arrayA` is properly sorted. We only need to perform this check if
+                    // `offsetA` has changed since we entered the loop.
+                    Debug.assertGreaterThanOrEqual(comparer(arrayA[offsetA], arrayA[offsetA - 1]), Comparison.EqualTo);
+                }
+
                 switch (comparer(arrayB[offsetB], arrayA[offsetA])) {
-                    case Comparison.LessThan: break inner;
-                    case Comparison.EqualTo: continue outer;
-                    case Comparison.GreaterThan: continue inner;
+                    case Comparison.LessThan:
+                        // If B is less than A, B does not exist in arrayA. Add B to the result and
+                        // move to the next element in arrayB without changing the current position
+                        // in arrayA.
+                        result.push(arrayB[offsetB]);
+                        continue loopB;
+                    case Comparison.EqualTo:
+                        // If B is equal to A, B exists in arrayA. Move to the next element in
+                        // arrayB without adding B to the result or changing the current position
+                        // in arrayA.
+                        continue loopB;
+                    case Comparison.GreaterThan:
+                        // If B is greater than A, we need to keep looking for B in arrayA. Move to
+                        // the next element in arrayA and recheck.
+                        continue loopA;
                 }
             }
-            result.push(arrayB[offsetB]);
         }
         return result;
     }
@@ -802,8 +872,7 @@ namespace ts {
         start = start === undefined ? 0 : toOffset(from, start);
         end = end === undefined ? from.length : toOffset(from, end);
         for (let i = start; i < end && i < from.length; i++) {
-            const v = from[i];
-            if (v !== undefined) {
+            if (from[i] !== undefined) {
                 to.push(from[i]);
             }
         }
@@ -813,8 +882,8 @@ namespace ts {
     /**
      * @return Whether the value was added.
      */
-    export function pushIfUnique<T>(array: T[], toAdd: T): boolean {
-        if (contains(array, toAdd)) {
+    export function pushIfUnique<T>(array: T[], toAdd: T, equalityComparer?: EqualityComparer<T>): boolean {
+        if (contains(array, toAdd, equalityComparer)) {
             return false;
         }
         else {
@@ -826,9 +895,9 @@ namespace ts {
     /**
      * Unlike `pushIfUnique`, this can take `undefined` as an input, and returns a new array.
      */
-    export function appendIfUnique<T>(array: T[] | undefined, toAdd: T): T[] {
+    export function appendIfUnique<T>(array: T[] | undefined, toAdd: T, equalityComparer?: EqualityComparer<T>): T[] {
         if (array) {
-            pushIfUnique(array, toAdd);
+            pushIfUnique(array, toAdd, equalityComparer);
             return array;
         }
         else {
@@ -836,14 +905,25 @@ namespace ts {
         }
     }
 
+    function stableSortIndices<T>(array: ReadonlyArray<T>, indices: number[], comparer: Comparer<T>) {
+        // sort indices by value then position
+        indices.sort((x, y) => comparer(array[x], array[y]) || compareValues(x, y));
+    }
+
+    /**
+     * Returns a new sorted array.
+     */
+    export function sort<T>(array: ReadonlyArray<T>, comparer: Comparer<T>) {
+        return array.slice().sort(comparer);
+    }
+
     /**
      * Stable sort of an array. Elements equal to each other maintain their relative position in the array.
      */
-    export function stableSort<T>(array: ReadonlyArray<T>, comparer: Comparer<T> = compareValues) {
-        return array
-            .map((_, i) => i) // create array of indices
-            .sort((x, y) => comparer(array[x], array[y]) || compareValues(x, y)) // sort indices by value then position
-            .map(i => array[i]); // get sorted array
+    export function stableSort<T>(array: ReadonlyArray<T>, comparer: Comparer<T>) {
+        const indices = array.map((_, i) => i);
+        stableSortIndices(array, indices, comparer);
+        return indices.map(i => array[i]);
     }
 
     export function rangeEquals<T>(array1: ReadonlyArray<T>, array2: ReadonlyArray<T>, pos: number, end: number) {
@@ -921,38 +1001,37 @@ namespace ts {
         return result;
     }
 
-    export type Comparer<T> = (a: T, b: T) => Comparison;
-
     /**
-     * Performs a binary search, finding the index at which 'value' occurs in 'array'.
+     * Performs a binary search, finding the index at which `value` occurs in `array`.
      * If no such index is found, returns the 2's-complement of first index at which
-     * number[index] exceeds number.
+     * `array[index]` exceeds `value`.
      * @param array A sorted array whose first element must be no larger than number
-     * @param number The value to be searched for in the array.
+     * @param value The value to be searched for in the array.
+     * @param keySelector A callback used to select the search key from `value` and each element of
+     * `array`.
+     * @param keyComparer A callback used to compare two keys in a sorted array.
+     * @param offset An offset into `array` at which to start the search.
      */
-    export function binarySearch<T>(array: ReadonlyArray<T>, value: T, comparer?: Comparer<T>, offset?: number): number {
+    export function binarySearch<T, U>(array: ReadonlyArray<T>, value: T, keySelector: (v: T) => U, keyComparer: Comparer<U>, offset?: number): number {
         if (!array || array.length === 0) {
             return -1;
         }
 
         let low = offset || 0;
         let high = array.length - 1;
-        comparer = comparer !== undefined
-            ? comparer
-            : (v1, v2) => (v1 < v2 ? -1 : (v1 > v2 ? 1 : 0));
-
+        const key = keySelector(value);
         while (low <= high) {
             const middle = low + ((high - low) >> 1);
-            const midValue = array[middle];
-
-            if (comparer(midValue, value) === 0) {
-                return middle;
-            }
-            else if (comparer(midValue, value) > 0) {
-                high = middle - 1;
-            }
-            else {
-                low = middle + 1;
+            const midKey = keySelector(array[middle]);
+            switch (keyComparer(midKey, key)) {
+                case Comparison.LessThan:
+                    low = middle + 1;
+                    break;
+                case Comparison.EqualTo:
+                    return middle;
+                case Comparison.GreaterThan:
+                    high = middle - 1;
+                    break;
             }
         }
 
@@ -985,32 +1064,6 @@ namespace ts {
         return initial;
     }
 
-    export function reduceRight<T, U>(array: ReadonlyArray<T>, f: (memo: U, value: T, i: number) => U, initial: U, start?: number, count?: number): U;
-    export function reduceRight<T>(array: ReadonlyArray<T>, f: (memo: T, value: T, i: number) => T): T;
-    export function reduceRight<T>(array: T[], f: (memo: T, value: T, i: number) => T, initial?: T, start?: number, count?: number): T {
-        if (array) {
-            const size = array.length;
-            if (size > 0) {
-                let pos = start === undefined || start > size - 1 ? size - 1 : start;
-                const end = count === undefined || pos - count < 0 ? 0 : pos - count;
-                let result: T;
-                if (arguments.length <= 2) {
-                    result = array[pos];
-                    pos--;
-                }
-                else {
-                    result = initial;
-                }
-                while (pos >= end) {
-                    result = f(result, array[pos], pos);
-                    pos--;
-                }
-                return result;
-            }
-        }
-        return initial;
-    }
-
     const hasOwnProperty = Object.prototype.hasOwnProperty;
 
     /**
@@ -1130,13 +1183,13 @@ namespace ts {
      * @param left A map-like whose properties should be compared.
      * @param right A map-like whose properties should be compared.
      */
-    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer?: (left: T, right: T) => boolean) {
+    export function equalOwnProperties<T>(left: MapLike<T>, right: MapLike<T>, equalityComparer: EqualityComparer<T> = equateValues) {
         if (left === right) return true;
         if (!left || !right) return false;
         for (const key in left) {
             if (hasOwnProperty.call(left, key)) {
                 if (!hasOwnProperty.call(right, key) === undefined) return false;
-                if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key]) return false;
+                if (!equalityComparer(left[key], right[key])) return false;
             }
         }
 
@@ -1288,7 +1341,7 @@ namespace ts {
     }
 
     /** Does nothing. */
-    export function noop(): void { }
+    export function noop(_?: {} | null | undefined): void { } // tslint:disable-line no-empty
 
     /** Do nothing and return false */
     export function returnFalse(): false { return false; }
@@ -1489,37 +1542,210 @@ namespace ts {
         return headChain;
     }
 
-    export function compareValues<T>(a: T, b: T): Comparison {
-        if (a === b) return Comparison.EqualTo;
-        if (a === undefined) return Comparison.LessThan;
-        if (b === undefined) return Comparison.GreaterThan;
-        return a < b ? Comparison.LessThan : Comparison.GreaterThan;
+    export function equateValues<T>(a: T, b: T) {
+        return a === b;
     }
 
-    export function compareStrings(a: string, b: string, ignoreCase?: boolean): Comparison {
+    /**
+     * Compare the equality of two strings using a case-sensitive ordinal comparison.
+     *
+     * Case-sensitive comparisons compare both strings one code-point at a time using the integer
+     * value of each code-point after applying `toUpperCase` to each string. We always map both
+     * strings to their upper-case form as some unicode characters do not properly round-trip to
+     * lowercase (such as `ẞ` (German sharp capital s)).
+     */
+    export function equateStringsCaseInsensitive(a: string, b: string) {
+        return a === b
+            || a !== undefined
+            && b !== undefined
+            && a.toUpperCase() === b.toUpperCase();
+    }
+
+    /**
+     * Compare the equality of two strings using a case-sensitive ordinal comparison.
+     *
+     * Case-sensitive comparisons compare both strings one code-point at a time using the
+     * integer value of each code-point.
+     */
+    export function equateStringsCaseSensitive(a: string, b: string) {
+        return equateValues(a, b);
+    }
+
+    function compareComparableValues(a: string, b: string): Comparison;
+    function compareComparableValues(a: number, b: number): Comparison;
+    function compareComparableValues(a: string | number, b: string | number) {
+        return a === b ? Comparison.EqualTo :
+            a === undefined ? Comparison.LessThan :
+            b === undefined ? Comparison.GreaterThan :
+            a < b ? Comparison.LessThan :
+            Comparison.GreaterThan;
+    }
+
+    /**
+     * Compare two numeric values for their order relative to each other.
+     * To compare strings, use any of the `compareStrings` functions.
+     */
+    export function compareValues(a: number, b: number) {
+        return compareComparableValues(a, b);
+    }
+
+    /**
+     * Compare two strings using a case-insensitive ordinal comparison.
+     *
+     * Ordinal comparisons are based on the difference between the unicode code points of both
+     * strings. Characters with multiple unicode representations are considered unequal. Ordinal
+     * comparisons provide predictable ordering, but place "a" after "B".
+     *
+     * Case-insensitive comparisons compare both strings one code-point at a time using the integer
+     * value of each code-point after applying `toUpperCase` to each string. We always map both
+     * strings to their upper-case form as some unicode characters do not properly round-trip to
+     * lowercase (such as `ẞ` (German sharp capital s)).
+     */
+    export function compareStringsCaseInsensitive(a: string, b: string) {
         if (a === b) return Comparison.EqualTo;
         if (a === undefined) return Comparison.LessThan;
         if (b === undefined) return Comparison.GreaterThan;
-        if (ignoreCase) {
-            // Checking if "collator exists indicates that Intl is available.
-            // We still have to check if "collator.compare" is correct. If it is not, use "String.localeComapre"
-            if (collator) {
-                const result = localeCompareIsCorrect ?
-                    collator.compare(a, b) :
-                    a.localeCompare(b, /*locales*/ undefined, { usage: "sort", sensitivity: "accent" });  // accent means a ≠ b, a ≠ á, a = A
-                return result < 0 ? Comparison.LessThan : result > 0 ? Comparison.GreaterThan : Comparison.EqualTo;
-            }
+        a = a.toUpperCase();
+        b = b.toUpperCase();
+        return a < b ? Comparison.LessThan : a > b ? Comparison.GreaterThan : Comparison.EqualTo;
+    }
 
-            a = a.toUpperCase();
-            b = b.toUpperCase();
+    /**
+     * Compare two strings using a case-sensitive ordinal comparison.
+     *
+     * Ordinal comparisons are based on the difference between the unicode code points of both
+     * strings. Characters with multiple unicode representations are considered unequal. Ordinal
+     * comparisons provide predictable ordering, but place "a" after "B".
+     *
+     * Case-sensitive comparisons compare both strings one code-point at a time using the integer
+     * value of each code-point.
+     */
+    export function compareStringsCaseSensitive(a: string, b: string) {
+        return compareComparableValues(a, b);
+    }
+
+    /**
+     * Creates a string comparer for use with string collation in the UI.
+     */
+    const createUIStringComparer = (() => {
+        let defaultComparer: Comparer<string> | undefined;
+        let enUSComparer: Comparer<string> | undefined;
+
+        const stringComparerFactory = getStringComparerFactory();
+        return createStringComparer;
+
+        function compareWithCallback(a: string | undefined, b: string | undefined, comparer: (a: string, b: string) => number) {
             if (a === b) return Comparison.EqualTo;
+            if (a === undefined) return Comparison.LessThan;
+            if (b === undefined) return Comparison.GreaterThan;
+            const value = comparer(a, b);
+            return value < 0 ? Comparison.LessThan : value > 0 ? Comparison.GreaterThan : Comparison.EqualTo;
         }
 
-        return a < b ? Comparison.LessThan : Comparison.GreaterThan;
+        function createIntlCollatorStringComparer(locale: string | undefined): Comparer<string> {
+            // Intl.Collator.prototype.compare is bound to the collator. See NOTE in
+            // http://www.ecma-international.org/ecma-402/2.0/#sec-Intl.Collator.prototype.compare
+            const comparer = new Intl.Collator(locale, { usage: "sort", sensitivity: "variant" }).compare;
+            return (a, b) => compareWithCallback(a, b, comparer);
+        }
+
+        function createLocaleCompareStringComparer(locale: string | undefined): Comparer<string> {
+            // if the locale is not the default locale (`undefined`), use the fallback comparer.
+            if (locale !== undefined) return createFallbackStringComparer();
+
+            return (a, b) => compareWithCallback(a, b, compareStrings);
+
+            function compareStrings(a: string, b: string) {
+                return a.localeCompare(b);
+            }
+        }
+
+        function createFallbackStringComparer(): Comparer<string> {
+            // An ordinal comparison puts "A" after "b", but for the UI we want "A" before "b".
+            // We first sort case insensitively.  So "Aaa" will come before "baa".
+            // Then we sort case sensitively, so "aaa" will come before "Aaa".
+            //
+            // For case insensitive comparisons we always map both strings to their
+            // upper-case form as some unicode characters do not properly round-trip to
+            // lowercase (such as `ẞ` (German sharp capital s)).
+            return (a, b) => compareWithCallback(a, b, compareDictionaryOrder);
+
+            function compareDictionaryOrder(a: string, b: string) {
+                return compareStrings(a.toUpperCase(), b.toUpperCase()) || compareStrings(a, b);
+            }
+
+            function compareStrings(a: string, b: string) {
+                return a < b ? Comparison.LessThan : a > b ? Comparison.GreaterThan : Comparison.EqualTo;
+            }
+        }
+
+        function getStringComparerFactory() {
+            // If the host supports Intl, we use it for comparisons using the default locale.
+            if (typeof Intl === "object" && typeof Intl.Collator === "function") {
+                return createIntlCollatorStringComparer;
+            }
+
+            // If the host does not support Intl, we fall back to localeCompare.
+            // localeCompare in Node v0.10 is just an ordinal comparison, so don't use it.
+            if (typeof String.prototype.localeCompare === "function" &&
+                typeof String.prototype.toLocaleUpperCase === "function" &&
+                "a".localeCompare("B") < 0) {
+                return createLocaleCompareStringComparer;
+            }
+
+            // Otherwise, fall back to ordinal comparison:
+            return createFallbackStringComparer;
+        }
+
+        function createStringComparer(locale: string | undefined) {
+            // Hold onto common string comparers. This avoids constantly reallocating comparers during
+            // tests.
+            if (locale === undefined) {
+                return defaultComparer || (defaultComparer = stringComparerFactory(locale));
+            }
+            else if (locale === "en-US") {
+                return enUSComparer || (enUSComparer = stringComparerFactory(locale));
+            }
+            else {
+                return stringComparerFactory(locale);
+            }
+        }
+    })();
+
+    let uiComparerCaseSensitive: Comparer<string> | undefined;
+    let uiLocale: string | undefined;
+
+    export function getUILocale() {
+        return uiLocale;
     }
 
-    export function compareStringsCaseInsensitive(a: string, b: string) {
-        return compareStrings(a, b, /*ignoreCase*/ true);
+    export function setUILocale(value: string) {
+        if (uiLocale !== value) {
+            uiLocale = value;
+            uiComparerCaseSensitive = undefined;
+        }
+    }
+
+    /**
+     * Compare two strings in a using the case-sensitive sort behavior of the UI locale.
+     *
+     * Ordering is not predictable between different host locales, but is best for displaying
+     * ordered data for UI presentation. Characters with multiple unicode representations may
+     * be considered equal.
+     *
+     * Case-sensitive comparisons compare strings that differ in base characters, or
+     * accents/diacritic marks, or case as unequal.
+     */
+    export function compareStringsCaseSensitiveUI(a: string, b: string) {
+        const comparer = uiComparerCaseSensitive || (uiComparerCaseSensitive = createUIStringComparer(uiLocale));
+        return comparer(a, b);
+    }
+
+    export function compareProperties<T, K extends keyof T>(a: T, b: T, key: K, comparer: Comparer<T[K]>) {
+        return a === b ? Comparison.EqualTo :
+            a === undefined ? Comparison.LessThan :
+            b === undefined ? Comparison.GreaterThan :
+            comparer(a[key], b[key]);
     }
 
     function getDiagnosticFileName(diagnostic: Diagnostic): string {
@@ -1527,7 +1753,7 @@ namespace ts {
     }
 
     export function compareDiagnostics(d1: Diagnostic, d2: Diagnostic): Comparison {
-        return compareValues(getDiagnosticFileName(d1), getDiagnosticFileName(d2)) ||
+        return compareStringsCaseSensitive(getDiagnosticFileName(d1), getDiagnosticFileName(d2)) ||
             compareValues(d1.start, d2.start) ||
             compareValues(d1.length, d2.length) ||
             compareValues(d1.code, d2.code) ||
@@ -1541,7 +1767,7 @@ namespace ts {
             const string1 = isString(text1) ? text1 : text1.messageText;
             const string2 = isString(text2) ? text2 : text2.messageText;
 
-            const res = compareValues(string1, string2);
+            const res = compareStringsCaseSensitive(string1, string2);
             if (res) {
                 return res;
             }
@@ -1559,27 +1785,8 @@ namespace ts {
         return text1 ? Comparison.GreaterThan : Comparison.LessThan;
     }
 
-    export function sortAndDeduplicateDiagnostics(diagnostics: Diagnostic[]): Diagnostic[] {
-        return deduplicateSortedDiagnostics(diagnostics.sort(compareDiagnostics));
-    }
-
-    export function deduplicateSortedDiagnostics(diagnostics: Diagnostic[]): Diagnostic[] {
-        if (diagnostics.length < 2) {
-            return diagnostics;
-        }
-
-        const newDiagnostics = [diagnostics[0]];
-        let previousDiagnostic = diagnostics[0];
-        for (let i = 1; i < diagnostics.length; i++) {
-            const currentDiagnostic = diagnostics[i];
-            const isDupe = compareDiagnostics(currentDiagnostic, previousDiagnostic) === Comparison.EqualTo;
-            if (!isDupe) {
-                newDiagnostics.push(currentDiagnostic);
-                previousDiagnostic = currentDiagnostic;
-            }
-        }
-
-        return newDiagnostics;
+    export function sortAndDeduplicateDiagnostics(diagnostics: ReadonlyArray<Diagnostic>): Diagnostic[] {
+        return sortAndDeduplicate(diagnostics, compareDiagnostics);
     }
 
     export function normalizeSlashes(path: string): string {
@@ -1600,7 +1807,6 @@ namespace ts {
         }
         if (path.charCodeAt(1) === CharacterCodes.colon) {
             if (path.charCodeAt(2) === CharacterCodes.slash) return 3;
-            return 2;
         }
         // Per RFC 1738 'file' URI schema has the shape file://<host>/<path>
         // if <host> is omitted then it is assumed that host value is 'localhost',
@@ -1710,6 +1916,19 @@ namespace ts {
         return moduleResolution;
     }
 
+    export function getAllowSyntheticDefaultImports(compilerOptions: CompilerOptions) {
+        const moduleKind = getEmitModuleKind(compilerOptions);
+        return compilerOptions.allowSyntheticDefaultImports !== undefined
+            ? compilerOptions.allowSyntheticDefaultImports
+            : moduleKind === ModuleKind.System;
+    }
+
+    export type StrictOptionName = "noImplicitAny" | "noImplicitThis" | "strictNullChecks" | "strictFunctionTypes" | "alwaysStrict";
+
+    export function getStrictOptionValue(compilerOptions: CompilerOptions, flag: StrictOptionName): boolean {
+        return compilerOptions[flag] === undefined ? compilerOptions.strict : compilerOptions[flag];
+    }
+
     export function hasZeroOrOneAsteriskCharacter(str: string): boolean {
         let seenAsterisk = false;
         for (let i = 0; i < str.length; i++) {
@@ -1904,8 +2123,9 @@ namespace ts {
         const aComponents = getNormalizedPathComponents(a, currentDirectory);
         const bComponents = getNormalizedPathComponents(b, currentDirectory);
         const sharedLength = Math.min(aComponents.length, bComponents.length);
+        const comparer = ignoreCase ? compareStringsCaseInsensitive : compareStringsCaseSensitive;
         for (let i = 0; i < sharedLength; i++) {
-            const result = compareStrings(aComponents[i], bComponents[i], ignoreCase);
+            const result = comparer(aComponents[i], bComponents[i]);
             if (result !== Comparison.EqualTo) {
                 return result;
             }
@@ -1926,9 +2146,9 @@ namespace ts {
             return false;
         }
 
+        const equalityComparer = ignoreCase ? equateStringsCaseInsensitive : equateStringsCaseSensitive;
         for (let i = 0; i < parentComponents.length; i++) {
-            const result = compareStrings(parentComponents[i], childComponents[i], ignoreCase);
-            if (result !== Comparison.EqualTo) {
+            if (!equalityComparer(parentComponents[i], childComponents[i])) {
                 return false;
             }
         }
@@ -2173,6 +2393,7 @@ namespace ts {
         path = normalizePath(path);
         currentDirectory = normalizePath(currentDirectory);
 
+        const comparer = useCaseSensitiveFileNames ? compareStringsCaseSensitive : compareStringsCaseInsensitive;
         const patterns = getFileMatcherPatterns(path, excludes, includes, useCaseSensitiveFileNames, currentDirectory);
 
         const regexFlag = useCaseSensitiveFileNames ? "" : "i";
@@ -2184,7 +2405,6 @@ namespace ts {
         // If there are no "includes", then just put everything in results[0].
         const results: string[][] = includeFileRegexes ? includeFileRegexes.map(() => []) : [[]];
 
-        const comparer = useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive;
         for (const basePath of patterns.basePaths) {
             visitDirectory(basePath, combinePaths(currentDirectory, basePath), depth);
         }
@@ -2192,10 +2412,9 @@ namespace ts {
         return flatten<string>(results);
 
         function visitDirectory(path: string, absolutePath: string, depth: number | undefined) {
-            let { files, directories } = getFileSystemEntries(path);
-            files = files.slice().sort(comparer);
+            const { files, directories } = getFileSystemEntries(path);
 
-            for (const current of files) {
+            for (const current of sort(files, comparer)) {
                 const name = combinePaths(path, current);
                 const absoluteName = combinePaths(absolutePath, current);
                 if (extensions && !fileExtensionIsOneOf(name, extensions)) continue;
@@ -2218,8 +2437,7 @@ namespace ts {
                 }
             }
 
-            directories = directories.slice().sort(comparer);
-            for (const current of directories) {
+            for (const current of sort(directories, comparer)) {
                 const name = combinePaths(path, current);
                 const absoluteName = combinePaths(absolutePath, current);
                 if ((!includeDirectoryRegex || includeDirectoryRegex.test(absoluteName)) &&
@@ -2249,7 +2467,7 @@ namespace ts {
             }
 
             // Sort the offsets array using either the literal or canonical path representations.
-            includeBasePaths.sort(useCaseSensitiveFileNames ? compareStrings : compareStringsCaseInsensitive);
+            includeBasePaths.sort(useCaseSensitiveFileNames ? compareStringsCaseSensitive : compareStringsCaseInsensitive);
 
             // Iterate over each include base path and include unique base paths that are not a
             // subpath of an existing base path
@@ -2316,7 +2534,11 @@ namespace ts {
         if (!extraFileExtensions || extraFileExtensions.length === 0 || !needAllExtensions) {
             return needAllExtensions ? allSupportedExtensions : supportedTypeScriptExtensions;
         }
-        return deduplicate([...allSupportedExtensions, ...extraFileExtensions.map(e => e.extension)]);
+        return deduplicate(
+            [...allSupportedExtensions, ...extraFileExtensions.map(e => e.extension)],
+            equateStringsCaseSensitive,
+            compareStringsCaseSensitive
+        );
     }
 
     export function hasJavaScriptFileExtension(fileName: string) {
@@ -2448,8 +2670,7 @@ namespace ts {
         }
     }
 
-    function Signature() {
-    }
+    function Signature() {} // tslint:disable-line no-empty
 
     function Node(this: Node, kind: SyntaxKind, pos: number, end: number) {
         this.id = 0;
@@ -2720,7 +2941,7 @@ namespace ts {
         return (arg: T) => f(arg) && g(arg);
     }
 
-    export function assertTypeIsNever(_: never): void { }
+    export function assertTypeIsNever(_: never): void { } // tslint:disable-line no-empty
 
     export interface FileAndDirectoryExistence {
         fileExists: boolean;
@@ -2887,10 +3108,9 @@ namespace ts {
         function addOrDeleteFileOrDirectory(fileOrDirectory: string, fileOrDirectoryPath: Path) {
             const existingResult = getCachedFileSystemEntries(fileOrDirectoryPath);
             if (existingResult) {
-                // This was a folder already present, remove it if this doesnt exist any more
-                if (!host.directoryExists(fileOrDirectory)) {
-                    cachedReadDirectoryResult.delete(fileOrDirectoryPath);
-                }
+                // Just clear the cache for now
+                // For now just clear the cache, since this could mean that multiple level entries might need to be re-evaluated
+                clearCache();
             }
             else {
                 // This was earlier a file (hence not in cached directory contents)
@@ -2903,8 +3123,14 @@ namespace ts {
                             fileExists: host.fileExists(fileOrDirectoryPath),
                             directoryExists: host.directoryExists(fileOrDirectoryPath)
                         };
-                        updateFilesOfFileSystemEntry(parentResult, baseName, fsQueryResult.fileExists);
-                        updateFileSystemEntry(parentResult.directories, baseName, fsQueryResult.directoryExists);
+                        if (fsQueryResult.directoryExists || hasEntry(parentResult.directories, baseName)) {
+                            // Folder added or removed, clear the cache instead of updating the folder and its structure
+                            clearCache();
+                        }
+                        else {
+                            // No need to update the directory structure, just files
+                            updateFilesOfFileSystemEntry(parentResult, baseName, fsQueryResult.fileExists);
+                        }
                         return fsQueryResult;
                     }
                 }
diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 48b97b048e9..3276e68b2ac 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -1429,45 +1429,40 @@ namespace ts {
             function getAccessorDeclarationTypeVisibilityError(symbolAccessibilityResult: SymbolAccessibilityResult): SymbolAccessibilityDiagnostic {
                 let diagnosticMessage: DiagnosticMessage;
                 if (accessorWithTypeAnnotation.kind === SyntaxKind.SetAccessor) {
-                    // Setters have to have type named and cannot infer it so, the type should always be named
-                    if (hasModifier(accessorWithTypeAnnotation.parent, ModifierFlags.Static)) {
+                    // Getters can infer the return type from the returned expression, but setters cannot, so the
+                    // "_from_external_module_1_but_cannot_be_named" case cannot occur.
+                    if (hasModifier(accessorWithTypeAnnotation, ModifierFlags.Static)) {
                         diagnosticMessage = symbolAccessibilityResult.errorModuleName ?
-                            Diagnostics.Parameter_0_of_public_static_property_setter_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
-                            Diagnostics.Parameter_0_of_public_static_property_setter_from_exported_class_has_or_is_using_private_name_1;
+                            Diagnostics.Parameter_type_of_public_static_setter_0_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
+                            Diagnostics.Parameter_type_of_public_static_setter_0_from_exported_class_has_or_is_using_private_name_1;
                     }
                     else {
                         diagnosticMessage = symbolAccessibilityResult.errorModuleName ?
-                            Diagnostics.Parameter_0_of_public_property_setter_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
-                            Diagnostics.Parameter_0_of_public_property_setter_from_exported_class_has_or_is_using_private_name_1;
+                            Diagnostics.Parameter_type_of_public_setter_0_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
+                            Diagnostics.Parameter_type_of_public_setter_0_from_exported_class_has_or_is_using_private_name_1;
                     }
-                    return {
-                        diagnosticMessage,
-                        errorNode: <Node>accessorWithTypeAnnotation.parameters[0],
-                        // TODO(jfreeman): Investigate why we are passing node.name instead of node.parameters[0].name
-                        typeName: accessorWithTypeAnnotation.name
-                    };
                 }
                 else {
                     if (hasModifier(accessorWithTypeAnnotation, ModifierFlags.Static)) {
                         diagnosticMessage = symbolAccessibilityResult.errorModuleName ?
                             symbolAccessibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
-                                Diagnostics.Return_type_of_public_static_property_getter_from_exported_class_has_or_is_using_name_0_from_external_module_1_but_cannot_be_named :
-                                Diagnostics.Return_type_of_public_static_property_getter_from_exported_class_has_or_is_using_name_0_from_private_module_1 :
-                            Diagnostics.Return_type_of_public_static_property_getter_from_exported_class_has_or_is_using_private_name_0;
+                                Diagnostics.Return_type_of_public_static_getter_0_from_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
+                                Diagnostics.Return_type_of_public_static_getter_0_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
+                            Diagnostics.Return_type_of_public_static_getter_0_from_exported_class_has_or_is_using_private_name_1;
                     }
                     else {
                         diagnosticMessage = symbolAccessibilityResult.errorModuleName ?
                             symbolAccessibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
-                                Diagnostics.Return_type_of_public_property_getter_from_exported_class_has_or_is_using_name_0_from_external_module_1_but_cannot_be_named :
-                                Diagnostics.Return_type_of_public_property_getter_from_exported_class_has_or_is_using_name_0_from_private_module_1 :
-                            Diagnostics.Return_type_of_public_property_getter_from_exported_class_has_or_is_using_private_name_0;
+                            Diagnostics.Return_type_of_public_getter_0_from_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
+                            Diagnostics.Return_type_of_public_getter_0_from_exported_class_has_or_is_using_name_1_from_private_module_2 :
+                        Diagnostics.Return_type_of_public_getter_0_from_exported_class_has_or_is_using_private_name_1;
                     }
-                    return {
-                        diagnosticMessage,
-                        errorNode: <Node>accessorWithTypeAnnotation.name,
-                        typeName: undefined
-                    };
                 }
+                return {
+                    diagnosticMessage,
+                    errorNode: <Node>accessorWithTypeAnnotation.name,
+                    typeName: accessorWithTypeAnnotation.name
+                };
             }
         }
 
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 0f88d5e4ac5..964264ff6e8 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1716,7 +1716,7 @@
         "category": "Error",
         "code": 2510
     },
-    "Cannot create an instance of the abstract class '{0}'.": {
+    "Cannot create an instance of an abstract class.": {
         "category": "Error",
         "code": 2511
     },
@@ -2321,43 +2321,43 @@
         "category": "Error",
         "code": 4033
     },
-    "Parameter '{0}' of public static property setter from exported class has or is using name '{1}' from private module '{2}'.": {
+    "Parameter type of public static setter '{0}' from exported class has or is using name '{1}' from private module '{2}'.": {
         "category": "Error",
         "code": 4034
     },
-    "Parameter '{0}' of public static property setter from exported class has or is using private name '{1}'.": {
+    "Parameter type of public static setter '{0}' from exported class has or is using private name '{1}'.": {
         "category": "Error",
         "code": 4035
     },
-    "Parameter '{0}' of public property setter from exported class has or is using name '{1}' from private module '{2}'.": {
+    "Parameter type of public setter '{0}' from exported class has or is using name '{1}' from private module '{2}'.": {
         "category": "Error",
         "code": 4036
     },
-    "Parameter '{0}' of public property setter from exported class has or is using private name '{1}'.": {
+    "Parameter type of public setter '{0}' from exported class has or is using private name '{1}'.": {
         "category": "Error",
         "code": 4037
     },
-    "Return type of public static property getter from exported class has or is using name '{0}' from external module {1} but cannot be named.": {
+    "Return type of public static getter '{0}' from exported class has or is using name '{1}' from external module {2} but cannot be named.": {
         "category": "Error",
         "code": 4038
     },
-    "Return type of public static property getter from exported class has or is using name '{0}' from private module '{1}'.": {
+    "Return type of public static getter '{0}' from exported class has or is using name '{1}' from private module '{2}'.": {
         "category": "Error",
         "code": 4039
     },
-    "Return type of public static property getter from exported class has or is using private name '{0}'.": {
+    "Return type of public static getter '{0}' from exported class has or is using private name '{1}'.": {
         "category": "Error",
         "code": 4040
     },
-    "Return type of public property getter from exported class has or is using name '{0}' from external module {1} but cannot be named.": {
+    "Return type of public getter '{0}' from exported class has or is using name '{1}' from external module {2} but cannot be named.": {
         "category": "Error",
         "code": 4041
     },
-    "Return type of public property getter from exported class has or is using name '{0}' from private module '{1}'.": {
+    "Return type of public getter '{0}' from exported class has or is using name '{1}' from private module '{2}'.": {
         "category": "Error",
         "code": 4042
     },
-    "Return type of public property getter from exported class has or is using private name '{0}'.": {
+    "Return type of public getter '{0}' from exported class has or is using private name '{1}'.": {
         "category": "Error",
         "code": 4043
     },
@@ -3615,6 +3615,18 @@
         "category": "Error",
         "code": 17013
     },
+    "JSX fragment has no corresponding closing tag.": {
+        "category": "Error",
+        "code": 17014
+    },
+    "Expected corresponding closing tag for JSX fragment.": {
+        "category": "Error",
+        "code": 17015
+    },
+    "JSX fragment is not supported when using --jsxFactory": {
+        "category": "Error",
+        "code":17016
+    },
 
     "Circularity detected while resolving configuration: {0}": {
         "category": "Error",
@@ -3781,5 +3793,21 @@
     "Infer parameter types from usage.": {
         "category": "Message",
         "code": 95012
+    },
+    "Convert to default import": {
+        "category": "Message",
+        "code": 95013
+    },
+    "Install '{0}'": {
+        "category": "Message",
+        "code": 95014
+    },
+    "Import '{0}' = require(\"{1}\").": {
+        "category": "Message",
+        "code": 95015
+    },
+    "Import * as '{0}' from \"{1}\".": {
+        "category": "Message",
+        "code": 95016
     }
 }
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 9ce220e723f..7a1d88d3bfd 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -699,9 +699,11 @@ namespace ts {
                 case SyntaxKind.JsxText:
                     return emitJsxText(<JsxText>node);
                 case SyntaxKind.JsxOpeningElement:
-                    return emitJsxOpeningElement(<JsxOpeningElement>node);
+                case SyntaxKind.JsxOpeningFragment:
+                    return emitJsxOpeningElementOrFragment(<JsxOpeningElement>node);
                 case SyntaxKind.JsxClosingElement:
-                    return emitJsxClosingElement(<JsxClosingElement>node);
+                case SyntaxKind.JsxClosingFragment:
+                    return emitJsxClosingElementOrFragment(<JsxClosingElement>node);
                 case SyntaxKind.JsxAttribute:
                     return emitJsxAttribute(<JsxAttribute>node);
                 case SyntaxKind.JsxAttributes:
@@ -836,6 +838,8 @@ namespace ts {
                     return emitJsxElement(<JsxElement>node);
                 case SyntaxKind.JsxSelfClosingElement:
                     return emitJsxSelfClosingElement(<JsxSelfClosingElement>node);
+                case SyntaxKind.JsxFragment:
+                    return emitJsxFragment(<JsxFragment>node);
 
                 // Transformation nodes
                 case SyntaxKind.PartiallyEmittedExpression:
@@ -1729,26 +1733,15 @@ namespace ts {
                         increaseIndent();
                     }
 
-                    if (getEmitFlags(node) & EmitFlags.ReuseTempVariableScope) {
-                        emitSignatureHead(node);
-                        if (onEmitNode) {
-                            onEmitNode(EmitHint.Unspecified, body, emitBlockCallback);
-                        }
-                        else {
-                            emitBlockFunctionBody(body);
-                        }
+                    pushNameGenerationScope(node);
+                    emitSignatureHead(node);
+                    if (onEmitNode) {
+                        onEmitNode(EmitHint.Unspecified, body, emitBlockCallback);
                     }
                     else {
-                        pushNameGenerationScope();
-                        emitSignatureHead(node);
-                        if (onEmitNode) {
-                            onEmitNode(EmitHint.Unspecified, body, emitBlockCallback);
-                        }
-                        else {
-                            emitBlockFunctionBody(body);
-                        }
-                        popNameGenerationScope();
+                        emitBlockFunctionBody(body);
                     }
+                    popNameGenerationScope(node);
 
                     if (indentedFlag) {
                         decreaseIndent();
@@ -1867,11 +1860,9 @@ namespace ts {
             emitTypeParameters(node, node.typeParameters);
             emitList(node, node.heritageClauses, ListFormat.ClassHeritageClauses);
 
-            pushNameGenerationScope();
             write(" {");
             emitList(node, node.members, ListFormat.ClassMembers);
             write("}");
-            popNameGenerationScope();
 
             if (indentedFlag) {
                 decreaseIndent();
@@ -1905,11 +1896,9 @@ namespace ts {
             emitModifiers(node, node.modifiers);
             write("enum ");
             emit(node.name);
-            pushNameGenerationScope();
             write(" {");
             emitList(node, node.members, ListFormat.EnumMembers);
             write("}");
-            popNameGenerationScope();
         }
 
         function emitModuleDeclaration(node: ModuleDeclaration) {
@@ -1931,11 +1920,11 @@ namespace ts {
         }
 
         function emitModuleBlock(node: ModuleBlock) {
-            pushNameGenerationScope();
+            pushNameGenerationScope(node);
             write("{");
             emitBlockStatements(node, /*forceSingleLine*/ isEmptyBlock(node));
             write("}");
-            popNameGenerationScope();
+            popNameGenerationScope(node);
         }
 
         function emitCaseBlock(node: CaseBlock) {
@@ -2060,7 +2049,7 @@ namespace ts {
 
         function emitJsxElement(node: JsxElement) {
             emit(node.openingElement);
-            emitList(node, node.children, ListFormat.JsxElementChildren);
+            emitList(node, node.children, ListFormat.JsxElementOrFragmentChildren);
             emit(node.closingElement);
         }
 
@@ -2075,14 +2064,24 @@ namespace ts {
             write("/>");
         }
 
-        function emitJsxOpeningElement(node: JsxOpeningElement) {
+        function emitJsxFragment(node: JsxFragment) {
+            emit(node.openingFragment);
+            emitList(node, node.children, ListFormat.JsxElementOrFragmentChildren);
+            emit(node.closingFragment);
+        }
+
+        function emitJsxOpeningElementOrFragment(node: JsxOpeningElement | JsxOpeningFragment) {
             write("<");
-            emitJsxTagName(node.tagName);
-            writeIfAny(node.attributes.properties, " ");
-            // We are checking here so we won't re-enter the emitting pipeline and emit extra sourcemap
-            if (node.attributes.properties && node.attributes.properties.length > 0) {
-                emit(node.attributes);
+
+            if (isJsxOpeningElement(node)) {
+                emitJsxTagName(node.tagName);
+                // We are checking here so we won't re-enter the emitting pipeline and emit extra sourcemap
+                if (node.attributes.properties && node.attributes.properties.length > 0) {
+                    write(" ");
+                    emit(node.attributes);
+                }
             }
+
             write(">");
         }
 
@@ -2090,9 +2089,11 @@ namespace ts {
             writer.writeLiteral(getTextOfNode(node, /*includeTrivia*/ true));
         }
 
-        function emitJsxClosingElement(node: JsxClosingElement) {
+        function emitJsxClosingElementOrFragment(node: JsxClosingElement | JsxClosingFragment) {
             write("</");
-            emitJsxTagName(node.tagName);
+            if (isJsxClosingElement(node)) {
+                emitJsxTagName(node.tagName);
+            }
             write(">");
         }
 
@@ -2268,11 +2269,11 @@ namespace ts {
 
         function emitSourceFileWorker(node: SourceFile) {
             const statements = node.statements;
-            pushNameGenerationScope();
+            pushNameGenerationScope(node);
             emitHelpersIndirect(node);
             const index = findIndex(statements, statement => !isPrologueDirective(statement));
             emitList(node, statements, ListFormat.MultiLine, index === -1 ? statements.length : index);
-            popNameGenerationScope();
+            popNameGenerationScope(node);
         }
 
         // Transformation nodes
@@ -2611,12 +2612,6 @@ namespace ts {
             writer.decreaseIndent();
         }
 
-        function writeIfAny(nodes: NodeArray<Node>, text: string) {
-            if (some(nodes)) {
-                write(text);
-            }
-        }
-
         function writeToken(token: SyntaxKind, pos: number, contextNode?: Node) {
             return onEmitSourceMapOfToken
                 ? onEmitSourceMapOfToken(contextNode, token, pos, writeTokenText)
@@ -2651,8 +2646,8 @@ namespace ts {
         function writeLines(text: string): void {
             const lines = text.split(/\r\n?|\n/g);
             const indentation = guessIndentation(lines);
-            for (let i = 0; i < lines.length; i++) {
-                const line = indentation ? lines[i].slice(indentation) : lines[i];
+            for (const lineText of lines) {
+                const line = indentation ? lineText.slice(indentation) : lineText;
                 if (line.length) {
                     writeLine();
                     write(line);
@@ -2741,7 +2736,7 @@ namespace ts {
                 }
             }
             else {
-                return nextNode.startsOnNewLine;
+                return getStartsOnNewLine(nextNode);
             }
         }
 
@@ -2772,7 +2767,7 @@ namespace ts {
 
         function synthesizedNodeStartsOnNewLine(node: Node, format?: ListFormat) {
             if (nodeIsSynthesized(node)) {
-                const startsOnNewLine = node.startsOnNewLine;
+                const startsOnNewLine = getStartsOnNewLine(node);
                 if (startsOnNewLine === undefined) {
                     return (format & ListFormat.PreferNewLine) !== 0;
                 }
@@ -2789,7 +2784,7 @@ namespace ts {
             node2 = skipSynthesizedParentheses(node2);
 
             // Always use a newline for synthesized code if the synthesizer desires it.
-            if (node2.startsOnNewLine) {
+            if (getStartsOnNewLine(node2)) {
                 return true;
             }
 
@@ -2848,7 +2843,10 @@ namespace ts {
         /**
          * Push a new name generation scope.
          */
-        function pushNameGenerationScope() {
+        function pushNameGenerationScope(node: Node | undefined) {
+            if (node && getEmitFlags(node) & EmitFlags.ReuseTempVariableScope) {
+                return;
+            }
             tempFlagsStack.push(tempFlags);
             tempFlags = 0;
         }
@@ -2856,7 +2854,10 @@ namespace ts {
         /**
          * Pop the current name generation scope.
          */
-        function popNameGenerationScope() {
+        function popNameGenerationScope(node: Node | undefined) {
+            if (node && getEmitFlags(node) & EmitFlags.ReuseTempVariableScope) {
+                return;
+            }
             tempFlags = tempFlagsStack.pop();
         }
 
@@ -2867,8 +2868,17 @@ namespace ts {
             if (name.autoGenerateKind === GeneratedIdentifierKind.Node) {
                 // Node names generate unique names based on their original node
                 // and are cached based on that node's id.
-                const node = getNodeForGeneratedName(name);
-                return generateNameCached(node);
+                if (name.skipNameGenerationScope) {
+                    const savedTempFlags = tempFlags;
+                    popNameGenerationScope(/*node*/ undefined);
+                    const result = generateNameCached(getNodeForGeneratedName(name));
+                    pushNameGenerationScope(/*node*/ undefined);
+                    tempFlags = savedTempFlags;
+                    return result;
+                  }
+                  else {
+                    return generateNameCached(getNodeForGeneratedName(name));
+                  }
             }
             else {
                 // Auto, Loop, and Unique names are cached based on their unique
@@ -3176,7 +3186,7 @@ namespace ts {
         EnumMembers = CommaDelimited | Indented | MultiLine,
         CaseBlockClauses = Indented | MultiLine,
         NamedImportsOrExportsElements = CommaDelimited | SpaceBetweenSiblings | AllowTrailingComma | SingleLine | SpaceBetweenBraces,
-        JsxElementChildren = SingleLine | NoInterveningComments,
+        JsxElementOrFragmentChildren = SingleLine | NoInterveningComments,
         JsxElementAttributes = SingleLine | SpaceBetweenSiblings | NoInterveningComments,
         CaseOrDefaultClauseStatements = Indented | MultiLine | NoTrailingNewLine | OptionalIfEmpty,
         HeritageClauseTypes = CommaDelimited | SpaceBetweenSiblings | SingleLine,
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 65c1c92f366..e8dfcbc1e94 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -13,9 +13,6 @@ namespace ts {
         if (updated !== original) {
             setOriginalNode(updated, original);
             setTextRange(updated, original);
-            if (original.startsOnNewLine) {
-                updated.startsOnNewLine = true;
-            }
             aggregateTransformFlags(updated);
         }
         return updated;
@@ -73,11 +70,10 @@ namespace ts {
 
     // Literals
 
-    export function createLiteral(value: string): StringLiteral;
+    /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
+    export function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
     export function createLiteral(value: number): NumericLiteral;
     export function createLiteral(value: boolean): BooleanLiteral;
-    /** Create a string literal whose source text is read from a source node during emit. */
-    export function createLiteral(sourceNode: StringLiteral | NumericLiteral | Identifier): StringLiteral;
     export function createLiteral(value: string | number | boolean): PrimaryExpression;
     export function createLiteral(value: string | number | boolean | StringLiteral | NumericLiteral | Identifier): PrimaryExpression {
         if (typeof value === "number") {
@@ -116,6 +112,7 @@ namespace ts {
 
     export function createIdentifier(text: string): Identifier;
     /* @internal */
+    // tslint:disable-next-line unified-signatures
     export function createIdentifier(text: string, typeArguments: ReadonlyArray<TypeNode>): Identifier;
     export function createIdentifier(text: string, typeArguments?: ReadonlyArray<TypeNode>): Identifier {
         const node = <Identifier>createSynthesizedNode(SyntaxKind.Identifier);
@@ -168,11 +165,15 @@ namespace ts {
     }
 
     /** Create a unique name generated for a node. */
-    export function getGeneratedNameForNode(node: Node): Identifier {
+    export function getGeneratedNameForNode(node: Node): Identifier;
+    // tslint:disable-next-line unified-signatures
+    /*@internal*/ export function getGeneratedNameForNode(node: Node, shouldSkipNameGenerationScope?: boolean): Identifier;
+    export function getGeneratedNameForNode(node: Node, shouldSkipNameGenerationScope?: boolean): Identifier {
         const name = createIdentifier("");
         name.autoGenerateKind = GeneratedIdentifierKind.Node;
         name.autoGenerateId = nextAutoGenerateId;
         name.original = node;
+        name.skipNameGenerationScope = !!shouldSkipNameGenerationScope;
         nextAutoGenerateId++;
         return name;
     }
@@ -1982,7 +1983,7 @@ namespace ts {
         node.decorators = asNodeArray(decorators);
         node.modifiers = asNodeArray(modifiers);
         node.isExportEquals = isExportEquals;
-        node.expression = expression;
+        node.expression = isExportEquals ? parenthesizeBinaryOperand(SyntaxKind.EqualsToken, expression, /*isLeftSideOfBinary*/ false, /*leftOperand*/ undefined) : parenthesizeDefaultExpression(expression);
         return node;
     }
 
@@ -2115,6 +2116,22 @@ namespace ts {
             : node;
     }
 
+    export function createJsxFragment(openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment) {
+        const node = <JsxFragment>createSynthesizedNode(SyntaxKind.JsxFragment);
+        node.openingFragment = openingFragment;
+        node.children = createNodeArray(children);
+        node.closingFragment = closingFragment;
+        return node;
+    }
+
+    export function updateJsxFragment(node: JsxFragment, openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment) {
+        return node.openingFragment !== openingFragment
+            || node.children !== children
+            || node.closingFragment !== closingFragment
+            ? updateNode(createJsxFragment(openingFragment, children, closingFragment), node)
+            : node;
+    }
+
     export function createJsxAttribute(name: Identifier, initializer: StringLiteral | JsxExpression) {
         const node = <JsxAttribute>createSynthesizedNode(SyntaxKind.JsxAttribute);
         node.name = name;
@@ -2625,7 +2642,7 @@ namespace ts {
     /**
      * Gets a custom text range to use when emitting source maps.
      */
-    export function getSourceMapRange(node: Node) {
+    export function getSourceMapRange(node: Node): SourceMapRange {
         const emitNode = node.emitNode;
         return (emitNode && emitNode.sourceMapRange) || node;
     }
@@ -2638,6 +2655,7 @@ namespace ts {
         return node;
     }
 
+    // tslint:disable-next-line variable-name
     let SourceMapSource: new (fileName: string, text: string, skipTrivia?: (pos: number) => number) => SourceMapSource;
 
     /**
@@ -2666,6 +2684,24 @@ namespace ts {
         return node;
     }
 
+    /**
+     * Gets a custom text range to use when emitting comments.
+     */
+    /*@internal*/
+    export function getStartsOnNewLine(node: Node) {
+        const emitNode = node.emitNode;
+        return emitNode && emitNode.startsOnNewLine;
+    }
+
+    /**
+     * Sets a custom text range to use when emitting comments.
+     */
+    /*@internal*/
+    export function setStartsOnNewLine<T extends Node>(node: T, newLine: boolean) {
+        getOrCreateEmitNode(node).startsOnNewLine = newLine;
+        return node;
+    }
+
     /**
      * Gets a custom text range to use when emitting comments.
      */
@@ -2824,7 +2860,8 @@ namespace ts {
             sourceMapRange,
             tokenSourceMapRanges,
             constantValue,
-            helpers
+            helpers,
+            startsOnNewLine,
         } = sourceEmitNode;
         if (!destEmitNode) destEmitNode = {};
         // We are using `.slice()` here in case `destEmitNode.leadingComments` is pushed to later.
@@ -2836,6 +2873,7 @@ namespace ts {
         if (tokenSourceMapRanges) destEmitNode.tokenSourceMapRanges = mergeTokenSourceMapRanges(tokenSourceMapRanges, destEmitNode.tokenSourceMapRanges);
         if (constantValue !== undefined) destEmitNode.constantValue = constantValue;
         if (helpers) destEmitNode.helpers = addRange(destEmitNode.helpers, helpers);
+        if (startsOnNewLine !== undefined) destEmitNode.startsOnNewLine = startsOnNewLine;
         return destEmitNode;
     }
 
@@ -2951,7 +2989,7 @@ namespace ts {
         );
     }
 
-    function createReactNamespace(reactNamespace: string, parent: JsxOpeningLikeElement) {
+    function createReactNamespace(reactNamespace: string, parent: JsxOpeningLikeElement | JsxOpeningFragment) {
         // To ensure the emit resolver can properly resolve the namespace, we need to
         // treat this identifier as if it were a source tree node by clearing the `Synthesized`
         // flag and setting a parent node.
@@ -2963,7 +3001,7 @@ namespace ts {
         return react;
     }
 
-    function createJsxFactoryExpressionFromEntityName(jsxFactory: EntityName, parent: JsxOpeningLikeElement): Expression {
+    function createJsxFactoryExpressionFromEntityName(jsxFactory: EntityName, parent: JsxOpeningLikeElement | JsxOpeningFragment): Expression {
         if (isQualifiedName(jsxFactory)) {
             const left = createJsxFactoryExpressionFromEntityName(jsxFactory.left, parent);
             const right = createIdentifier(idText(jsxFactory.right));
@@ -2975,7 +3013,7 @@ namespace ts {
         }
     }
 
-    function createJsxFactoryExpression(jsxFactoryEntity: EntityName, reactNamespace: string, parent: JsxOpeningLikeElement): Expression {
+    function createJsxFactoryExpression(jsxFactoryEntity: EntityName, reactNamespace: string, parent: JsxOpeningLikeElement | JsxOpeningFragment): Expression {
         return jsxFactoryEntity ?
             createJsxFactoryExpressionFromEntityName(jsxFactoryEntity, parent) :
             createPropertyAccess(
@@ -2997,7 +3035,38 @@ namespace ts {
 
             if (children.length > 1) {
                 for (const child of children) {
-                    child.startsOnNewLine = true;
+                    startOnNewLine(child);
+                    argumentsList.push(child);
+                }
+            }
+            else {
+                argumentsList.push(children[0]);
+            }
+        }
+
+        return setTextRange(
+            createCall(
+                createJsxFactoryExpression(jsxFactoryEntity, reactNamespace, parentElement),
+                /*typeArguments*/ undefined,
+                argumentsList
+            ),
+            location
+        );
+    }
+
+    export function createExpressionForJsxFragment(jsxFactoryEntity: EntityName, reactNamespace: string, children: Expression[], parentElement: JsxOpeningFragment, location: TextRange): LeftHandSideExpression {
+        const tagName = createPropertyAccess(
+            createReactNamespace(reactNamespace, parentElement),
+            "Fragment"
+        );
+
+        const argumentsList = [<Expression>tagName];
+        argumentsList.push(createNull());
+
+        if (children && children.length > 0) {
+            if (children.length > 1) {
+                for (const child of children) {
+                    startOnNewLine(child);
                     argumentsList.push(child);
                 }
             }
@@ -3572,8 +3641,8 @@ namespace ts {
         );
         setOriginalNode(updated, node);
         setTextRange(updated, node);
-        if (node.startsOnNewLine) {
-            updated.startsOnNewLine = true;
+        if (getStartsOnNewLine(node)) {
+            setStartsOnNewLine(updated, /*newLine*/ true);
         }
         aggregateTransformFlags(updated);
         return updated;
@@ -3885,6 +3954,27 @@ namespace ts {
             : e;
     }
 
+    /**
+     *  [Per the spec](https://tc39.github.io/ecma262/#prod-ExportDeclaration), `export default` accepts _AssigmentExpression_ but
+     *  has a lookahead restriction for `function`, `async function`, and `class`.
+     *
+     * Basically, that means we need to parenthesize in the following cases:
+     *
+     * - BinaryExpression of CommaToken
+     * - CommaList (synthetic list of multiple comma expressions)
+     * - FunctionExpression
+     * - ClassExpression
+     */
+    export function parenthesizeDefaultExpression(e: Expression) {
+        const check = skipPartiallyEmittedExpressions(e);
+        return (check.kind === SyntaxKind.ClassExpression ||
+            check.kind === SyntaxKind.FunctionExpression ||
+            check.kind === SyntaxKind.CommaListExpression ||
+            isBinaryExpression(check) && check.operatorToken.kind === SyntaxKind.CommaToken)
+            ? createParen(e)
+            : e;
+    }
+
     /**
      * Wraps an expression in parentheses if it is needed in order to use the expression
      * as the expression of a NewExpression node.
@@ -4181,8 +4271,7 @@ namespace ts {
     }
 
     export function startOnNewLine<T extends Node>(node: T): T {
-        node.startsOnNewLine = true;
-        return node;
+        return setStartsOnNewLine(node, /*newLine*/ true);
     }
 
     export function getExternalHelpersModuleName(node: SourceFile) {
@@ -4230,7 +4319,7 @@ namespace ts {
         const namespaceDeclaration = getNamespaceDeclarationNode(node);
         if (namespaceDeclaration && !isDefaultImport(node)) {
             const name = namespaceDeclaration.name;
-            return isGeneratedIdentifier(name) ? name : createIdentifier(getSourceTextOfNodeFromSourceFile(sourceFile, namespaceDeclaration.name));
+            return isGeneratedIdentifier(name) ? name : createIdentifier(getSourceTextOfNodeFromSourceFile(sourceFile, name) || idText(name));
         }
         if (node.kind === SyntaxKind.ImportDeclaration && (<ImportDeclaration>node).importClause) {
             return getGeneratedNameForNode(node);
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index b27d4811ecb..79b5eb30c49 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -12,10 +12,12 @@ namespace ts {
         JSDoc = 1 << 5,
     }
 
+    // tslint:disable variable-name
     let NodeConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
     let TokenConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
     let IdentifierConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
     let SourceFileConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
+    // tslint:enable variable-name
 
     export function createNode(kind: SyntaxKind, pos?: number, end?: number): Node {
         if (kind === SyntaxKind.SourceFile) {
@@ -377,6 +379,10 @@ namespace ts {
                 return visitNode(cbNode, (<JsxElement>node).openingElement) ||
                     visitNodes(cbNode, cbNodes, (<JsxElement>node).children) ||
                     visitNode(cbNode, (<JsxElement>node).closingElement);
+            case SyntaxKind.JsxFragment:
+                return visitNode(cbNode, (<JsxFragment>node).openingFragment) ||
+                    visitNodes(cbNode, cbNodes, (<JsxFragment>node).children) ||
+                    visitNode(cbNode, (<JsxFragment>node).closingFragment);
             case SyntaxKind.JsxSelfClosingElement:
             case SyntaxKind.JsxOpeningElement:
                 return visitNode(cbNode, (<JsxOpeningLikeElement>node).tagName) ||
@@ -520,10 +526,12 @@ namespace ts {
         const disallowInAndDecoratorContext = NodeFlags.DisallowInContext | NodeFlags.DecoratorContext;
 
         // capture constructors in 'initializeState' to avoid null checks
+        // tslint:disable variable-name
         let NodeConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
         let TokenConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
         let IdentifierConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
         let SourceFileConstructor: new (kind: SyntaxKind, pos: number, end: number) => Node;
+        // tslint:enable variable-name
 
         let sourceFile: SourceFile;
         let parseDiagnostics: Diagnostic[];
@@ -627,6 +635,7 @@ namespace ts {
         }
 
         export function parseIsolatedEntityName(content: string, languageVersion: ScriptTarget): EntityName {
+            // Choice of `isDeclarationFile` should be arbitrary
             initializeState(content, languageVersion, /*syntaxCursor*/ undefined, ScriptKind.JS);
             // Prime the scanner.
             nextToken();
@@ -639,7 +648,7 @@ namespace ts {
         export function parseJsonText(fileName: string, sourceText: string): JsonSourceFile {
             initializeState(sourceText, ScriptTarget.ES2015, /*syntaxCursor*/ undefined, ScriptKind.JSON);
             // Set source file so that errors will be reported with this file name
-            sourceFile = createSourceFile(fileName, ScriptTarget.ES2015, ScriptKind.JSON);
+            sourceFile = createSourceFile(fileName, ScriptTarget.ES2015, ScriptKind.JSON, /*isDeclaration*/ false);
             const result = <JsonSourceFile>sourceFile;
 
             // Prime the scanner.
@@ -681,7 +690,16 @@ namespace ts {
             identifierCount = 0;
             nodeCount = 0;
 
-            contextFlags = scriptKind === ScriptKind.JS || scriptKind === ScriptKind.JSX || scriptKind === ScriptKind.JSON ? NodeFlags.JavaScriptFile : NodeFlags.None;
+            switch (scriptKind) {
+                case ScriptKind.JS:
+                case ScriptKind.JSX:
+                case ScriptKind.JSON:
+                    contextFlags = NodeFlags.JavaScriptFile;
+                    break;
+                default:
+                    contextFlags = NodeFlags.None;
+                    break;
+            }
             parseErrorBeforeNextFinishedNode = false;
 
             // Initialize and prime the scanner before parsing the source elements.
@@ -705,7 +723,12 @@ namespace ts {
         }
 
         function parseSourceFileWorker(fileName: string, languageVersion: ScriptTarget, setParentNodes: boolean, scriptKind: ScriptKind): SourceFile {
-            sourceFile = createSourceFile(fileName, languageVersion, scriptKind);
+            const isDeclarationFile = isDeclarationFileName(fileName);
+            if (isDeclarationFile) {
+                contextFlags |= NodeFlags.Ambient;
+            }
+
+            sourceFile = createSourceFile(fileName, languageVersion, scriptKind, isDeclarationFile);
             sourceFile.flags = contextFlags;
 
             // Prime the scanner.
@@ -782,7 +805,7 @@ namespace ts {
             }
         }
 
-        function createSourceFile(fileName: string, languageVersion: ScriptTarget, scriptKind: ScriptKind): SourceFile {
+        function createSourceFile(fileName: string, languageVersion: ScriptTarget, scriptKind: ScriptKind, isDeclarationFile: boolean): SourceFile {
             // code from createNode is inlined here so createNode won't have to deal with special case of creating source files
             // this is quite rare comparing to other nodes and createNode should be as fast as possible
             const sourceFile = <SourceFile>new SourceFileConstructor(SyntaxKind.SourceFile, /*pos*/ 0, /* end */ sourceText.length);
@@ -793,7 +816,7 @@ namespace ts {
             sourceFile.languageVersion = languageVersion;
             sourceFile.fileName = normalizePath(fileName);
             sourceFile.languageVariant = getLanguageVariant(scriptKind);
-            sourceFile.isDeclarationFile = fileExtensionIs(sourceFile.fileName, Extension.Dts);
+            sourceFile.isDeclarationFile = isDeclarationFile;
             sourceFile.scriptKind = scriptKind;
 
             return sourceFile;
@@ -1423,6 +1446,11 @@ namespace ts {
             return tokenIsIdentifierOrKeyword(token());
         }
 
+        function nextTokenIsIdentifierOrKeywordOrGreaterThan() {
+            nextToken();
+            return tokenIsIdentifierOrKeywordOrGreaterThan(token());
+        }
+
         function isHeritageClauseExtendsOrImplementsKeyword(): boolean {
             if (token() === SyntaxKind.ImplementsKeyword ||
                 token() === SyntaxKind.ExtendsKeyword) {
@@ -3802,9 +3830,9 @@ namespace ts {
                 node.operand = parseLeftHandSideExpressionOrHigher();
                 return finishNode(node);
             }
-            else if (sourceFile.languageVariant === LanguageVariant.JSX && token() === SyntaxKind.LessThanToken && lookAhead(nextTokenIsIdentifierOrKeyword)) {
+            else if (sourceFile.languageVariant === LanguageVariant.JSX && token() === SyntaxKind.LessThanToken && lookAhead(nextTokenIsIdentifierOrKeywordOrGreaterThan)) {
                 // JSXElement is part of primaryExpression
-                return parseJsxElementOrSelfClosingElement(/*inExpressionContext*/ true);
+                return parseJsxElementOrSelfClosingElementOrFragment(/*inExpressionContext*/ true);
             }
 
             const expression = parseLeftHandSideExpressionOrHigher();
@@ -3959,14 +3987,14 @@ namespace ts {
         }
 
 
-        function parseJsxElementOrSelfClosingElement(inExpressionContext: boolean): JsxElement | JsxSelfClosingElement {
-            const opening = parseJsxOpeningOrSelfClosingElement(inExpressionContext);
-            let result: JsxElement | JsxSelfClosingElement;
+        function parseJsxElementOrSelfClosingElementOrFragment(inExpressionContext: boolean): JsxElement | JsxSelfClosingElement | JsxFragment {
+            const opening = parseJsxOpeningOrSelfClosingElementOrOpeningFragment(inExpressionContext);
+            let result: JsxElement | JsxSelfClosingElement | JsxFragment;
             if (opening.kind === SyntaxKind.JsxOpeningElement) {
                 const node = <JsxElement>createNode(SyntaxKind.JsxElement, opening.pos);
                 node.openingElement = opening;
 
-                node.children = parseJsxChildren(node.openingElement.tagName);
+                node.children = parseJsxChildren(node.openingElement);
                 node.closingElement = parseJsxClosingElement(inExpressionContext);
 
                 if (!tagNamesAreEquivalent(node.openingElement.tagName, node.closingElement.tagName)) {
@@ -3975,6 +4003,14 @@ namespace ts {
 
                 result = finishNode(node);
             }
+            else if (opening.kind === SyntaxKind.JsxOpeningFragment) {
+                const node = <JsxFragment>createNode(SyntaxKind.JsxFragment, opening.pos);
+                node.openingFragment = opening;
+                node.children = parseJsxChildren(node.openingFragment);
+                node.closingFragment = parseJsxClosingFragment(inExpressionContext);
+
+                result = finishNode(node);
+            }
             else {
                 Debug.assert(opening.kind === SyntaxKind.JsxSelfClosingElement);
                 // Nothing else to do for self-closing elements
@@ -3989,7 +4025,7 @@ namespace ts {
             // Since JSX elements are invalid < operands anyway, this lookahead parse will only occur in error scenarios
             // of one sort or another.
             if (inExpressionContext && token() === SyntaxKind.LessThanToken) {
-                const invalidElement = tryParse(() => parseJsxElementOrSelfClosingElement(/*inExpressionContext*/ true));
+                const invalidElement = tryParse(() => parseJsxElementOrSelfClosingElementOrFragment(/*inExpressionContext*/ true));
                 if (invalidElement) {
                     parseErrorAtCurrentToken(Diagnostics.JSX_expressions_must_have_one_parent_element);
                     const badNode = <BinaryExpression>createNode(SyntaxKind.BinaryExpression, result.pos);
@@ -4020,12 +4056,12 @@ namespace ts {
                 case SyntaxKind.OpenBraceToken:
                     return parseJsxExpression(/*inExpressionContext*/ false);
                 case SyntaxKind.LessThanToken:
-                    return parseJsxElementOrSelfClosingElement(/*inExpressionContext*/ false);
+                    return parseJsxElementOrSelfClosingElementOrFragment(/*inExpressionContext*/ false);
             }
             Debug.fail("Unknown JSX child kind " + token());
         }
 
-        function parseJsxChildren(openingTagName: LeftHandSideExpression): NodeArray<JsxChild> {
+        function parseJsxChildren(openingTag: JsxOpeningElement | JsxOpeningFragment): NodeArray<JsxChild> {
             const list = [];
             const listPos = getNodePos();
             const saveParsingContext = parsingContext;
@@ -4040,7 +4076,13 @@ namespace ts {
                 else if (token() === SyntaxKind.EndOfFileToken) {
                     // If we hit EOF, issue the error at the tag that lacks the closing element
                     // rather than at the end of the file (which is useless)
-                    parseErrorAtPosition(openingTagName.pos, openingTagName.end - openingTagName.pos, Diagnostics.JSX_element_0_has_no_corresponding_closing_tag, getTextOfNodeFromSourceText(sourceText, openingTagName));
+                    if (isJsxOpeningFragment(openingTag)) {
+                        parseErrorAtPosition(openingTag.pos, openingTag.end - openingTag.pos, Diagnostics.JSX_fragment_has_no_corresponding_closing_tag);
+                    }
+                    else {
+                        const openingTagName = openingTag.tagName;
+                        parseErrorAtPosition(openingTagName.pos, openingTagName.end - openingTagName.pos, Diagnostics.JSX_element_0_has_no_corresponding_closing_tag, getTextOfNodeFromSourceText(sourceText, openingTagName));
+                    }
                     break;
                 }
                 else if (token() === SyntaxKind.ConflictMarkerTrivia) {
@@ -4063,11 +4105,17 @@ namespace ts {
             return finishNode(jsxAttributes);
         }
 
-        function parseJsxOpeningOrSelfClosingElement(inExpressionContext: boolean): JsxOpeningElement | JsxSelfClosingElement {
+        function parseJsxOpeningOrSelfClosingElementOrOpeningFragment(inExpressionContext: boolean): JsxOpeningElement | JsxSelfClosingElement | JsxOpeningFragment {
             const fullStart = scanner.getStartPos();
 
             parseExpected(SyntaxKind.LessThanToken);
 
+            if (token() === SyntaxKind.GreaterThanToken) {
+                parseExpected(SyntaxKind.GreaterThanToken);
+                const node: JsxOpeningFragment = <JsxOpeningFragment>createNode(SyntaxKind.JsxOpeningFragment, fullStart);
+                return finishNode(node);
+            }
+
             const tagName = parseJsxElementName();
             const attributes = parseJsxAttributes();
 
@@ -4179,6 +4227,23 @@ namespace ts {
             return finishNode(node);
         }
 
+        function parseJsxClosingFragment(inExpressionContext: boolean): JsxClosingFragment {
+            const node = <JsxClosingFragment>createNode(SyntaxKind.JsxClosingFragment);
+            parseExpected(SyntaxKind.LessThanSlashToken);
+            if (tokenIsIdentifierOrKeyword(token())) {
+                const unexpectedTagName = parseJsxElementName();
+                parseErrorAtPosition(unexpectedTagName.pos, unexpectedTagName.end - unexpectedTagName.pos, Diagnostics.Expected_corresponding_closing_tag_for_JSX_fragment);
+            }
+            if (inExpressionContext) {
+                parseExpected(SyntaxKind.GreaterThanToken);
+            }
+            else {
+                parseExpected(SyntaxKind.GreaterThanToken, /*diagnostic*/ undefined, /*shouldAdvance*/ false);
+                scanJsxText();
+            }
+            return finishNode(node);
+        }
+
         function parseTypeAssertion(): TypeAssertion {
             const node = <TypeAssertion>createNode(SyntaxKind.TypeAssertionExpression);
             parseExpected(SyntaxKind.LessThanToken);
@@ -5089,6 +5154,18 @@ namespace ts {
             const fullStart = getNodePos();
             const decorators = parseDecorators();
             const modifiers = parseModifiers();
+            if (some(modifiers, m => m.kind === SyntaxKind.DeclareKeyword)) {
+                for (const m of modifiers) {
+                    m.flags |= NodeFlags.Ambient;
+                }
+                return doInsideOfContext(NodeFlags.Ambient, () => parseDeclarationWorker(fullStart, decorators, modifiers));
+            }
+            else {
+                return parseDeclarationWorker(fullStart, decorators, modifiers);
+            }
+        }
+
+        function parseDeclarationWorker(fullStart: number, decorators: NodeArray<Decorator> | undefined, modifiers: NodeArray<Modifier> | undefined): Statement {
             switch (token()) {
                 case SyntaxKind.VarKeyword:
                 case SyntaxKind.LetKeyword:
@@ -5446,8 +5523,8 @@ namespace ts {
             return false;
         }
 
-        function parseDecorators(): NodeArray<Decorator> {
-            let list: Decorator[];
+        function parseDecorators(): NodeArray<Decorator> | undefined {
+            let list: Decorator[] | undefined;
             const listPos = getNodePos();
             while (true) {
                 const decoratorStart = getNodePos();
@@ -6069,7 +6146,7 @@ namespace ts {
                     const checkJsDirectiveMatchResult = checkJsDirectiveRegEx.exec(comment);
                     if (checkJsDirectiveMatchResult) {
                         checkJsDirective = {
-                            enabled: compareStrings(checkJsDirectiveMatchResult[1], "@ts-check", /*ignoreCase*/ true) === Comparison.EqualTo,
+                            enabled: equateStringsCaseInsensitive(checkJsDirectiveMatchResult[1], "@ts-check"),
                             end: range.end,
                             pos: range.pos
                         };
@@ -6131,7 +6208,7 @@ namespace ts {
         export namespace JSDocParser {
             export function parseJSDocTypeExpressionForTests(content: string, start: number, length: number): { jsDocTypeExpression: JSDocTypeExpression, diagnostics: Diagnostic[] } | undefined {
                 initializeState(content, ScriptTarget.Latest, /*_syntaxCursor:*/ undefined, ScriptKind.JS);
-                sourceFile = createSourceFile("file.js", ScriptTarget.Latest, ScriptKind.JS);
+                sourceFile = createSourceFile("file.js", ScriptTarget.Latest, ScriptKind.JS, /*isDeclarationFile*/ false);
                 scanner.setText(content, start, length);
                 currentToken = scanner.scan();
                 const jsDocTypeExpression = parseJSDocTypeExpression();
@@ -7461,4 +7538,8 @@ namespace ts {
             Value = -1
         }
     }
+
+    function isDeclarationFileName(fileName: string): boolean {
+        return fileExtensionIs(fileName, Extension.Dts);
+    }
 }
diff --git a/src/compiler/performance.ts b/src/compiler/performance.ts
index 8c24b3b9f1b..225b34de9cf 100644
--- a/src/compiler/performance.ts
+++ b/src/compiler/performance.ts
@@ -10,9 +10,7 @@ namespace ts {
 namespace ts.performance {
     declare const onProfilerEvent: { (markName: string): void; profiler: boolean; };
 
-    const profilerEvent = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true
-            ? onProfilerEvent
-            : (_markName: string) => { };
+    const profilerEvent: (markName: string) => void = typeof onProfilerEvent === "function" && onProfilerEvent.profiler === true ? onProfilerEvent : noop;
 
     let enabled = false;
     let profilerStart = 0;
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 0ff78a77ecd..cf7c03556f1 100755
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -7,18 +7,10 @@ namespace ts {
     const ignoreDiagnosticCommentRegEx = /(^\s*$)|(^\s*\/\/\/?\s*(@ts-ignore)?)/;
 
     export function findConfigFile(searchPath: string, fileExists: (fileName: string) => boolean, configName = "tsconfig.json"): string {
-        while (true) {
-            const fileName = combinePaths(searchPath, configName);
-            if (fileExists(fileName)) {
-                return fileName;
-            }
-            const parentPath = getDirectoryPath(searchPath);
-            if (parentPath === searchPath) {
-                break;
-            }
-            searchPath = parentPath;
-        }
-        return undefined;
+        return forEachAncestorDirectory(searchPath, ancestor => {
+            const fileName = combinePaths(ancestor, configName);
+            return fileExists(fileName) ? fileName : undefined;
+        });
     }
 
     export function resolveTripleslashReference(moduleName: string, containingFile: string): string {
@@ -1101,11 +1093,12 @@ namespace ts {
 
             // If '--lib' is not specified, include default library file according to '--target'
             // otherwise, using options specified in '--lib' instead of '--target' default library file
+            const equalityComparer = host.useCaseSensitiveFileNames() ? equateStringsCaseSensitive : equateStringsCaseInsensitive;
             if (!options.lib) {
-               return compareStrings(file.fileName, getDefaultLibraryFileName(), /*ignoreCase*/ !host.useCaseSensitiveFileNames()) === Comparison.EqualTo;
+               return equalityComparer(file.fileName, getDefaultLibraryFileName());
             }
             else {
-                return forEach(options.lib, libFileName => compareStrings(file.fileName, combinePaths(defaultLibraryPath, libFileName), /*ignoreCase*/ !host.useCaseSensitiveFileNames()) === Comparison.EqualTo);
+                return forEach(options.lib, libFileName => equalityComparer(file.fileName, combinePaths(defaultLibraryPath, libFileName)));
             }
         }
 
@@ -1186,11 +1179,11 @@ namespace ts {
             return emitResult;
         }
 
-        function getSourceFile(fileName: string): SourceFile {
+        function getSourceFile(fileName: string): SourceFile | undefined {
             return getSourceFileByPath(toPath(fileName));
         }
 
-        function getSourceFileByPath(path: Path): SourceFile {
+        function getSourceFileByPath(path: Path): SourceFile | undefined {
             return filesByName.get(path);
         }
 
@@ -2131,7 +2124,7 @@ namespace ts {
                 createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, "lib", "noLib");
             }
 
-            if (options.noImplicitUseStrict && (options.alwaysStrict === undefined ? options.strict : options.alwaysStrict)) {
+            if (options.noImplicitUseStrict && getStrictOptionValue(options, "alwaysStrict")) {
                 createDiagnosticForOptionName(Diagnostics.Option_0_cannot_be_specified_with_option_1, "noImplicitUseStrict", "alwaysStrict");
             }
 
@@ -2360,7 +2353,7 @@ namespace ts {
             return options.jsx ? undefined : Diagnostics.Module_0_was_resolved_to_1_but_jsx_is_not_set;
         }
         function needAllowJs() {
-            return options.allowJs || !options.noImplicitAny ? undefined : Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type;
+            return options.allowJs || !getStrictOptionValue(options, "noImplicitAny") ? undefined : Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type;
         }
     }
 
diff --git a/src/compiler/resolutionCache.ts b/src/compiler/resolutionCache.ts
index b988da0fd5f..e21e81a2e88 100644
--- a/src/compiler/resolutionCache.ts
+++ b/src/compiler/resolutionCache.ts
@@ -69,9 +69,8 @@ namespace ts {
 
     export const maxNumberOfFilesToIterateForInvalidation = 256;
 
-    interface GetResolutionWithResolvedFileName<T extends ResolutionWithFailedLookupLocations = ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName = ResolutionWithResolvedFileName> {
-        (resolution: T): R;
-    }
+    type GetResolutionWithResolvedFileName<T extends ResolutionWithFailedLookupLocations = ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName = ResolutionWithResolvedFileName> =
+        (resolution: T) => R;
 
     export function createResolutionCache(resolutionHost: ResolutionCacheHost, rootDirForResolution: string): ResolutionCache {
         let filesWithChangedSetOfUnresolvedImports: Path[] | undefined;
@@ -320,6 +319,10 @@ namespace ts {
             return endsWith(dirPath, "/node_modules");
         }
 
+        function isNodeModulesAtTypesDirectory(dirPath: Path) {
+            return endsWith(dirPath, "/node_modules/@types");
+        }
+
         function isDirectoryAtleastAtLevelFromFSRoot(dirPath: Path, minLevels: number) {
             for (let searchIndex = getRootLength(dirPath); minLevels > 0; minLevels--) {
                 searchIndex = dirPath.indexOf(directorySeparator, searchIndex) + 1;
@@ -560,11 +563,21 @@ namespace ts {
             else {
                 // Some file or directory in the watching directory is created
                 // Return early if it does not have any of the watching extension or not the custom failed lookup path
-                if (!isPathWithDefaultFailedLookupExtension(fileOrDirectoryPath) && !customFailedLookupPaths.has(fileOrDirectoryPath)) {
-                    return false;
+                const dirOfFileOrDirectory = getDirectoryPath(fileOrDirectoryPath);
+                if (isNodeModulesAtTypesDirectory(dirOfFileOrDirectory) || isNodeModulesDirectory(dirOfFileOrDirectory)) {
+                    // Invalidate any resolution from this directory
+                    isChangedFailedLookupLocation = location => {
+                        const locationPath = resolutionHost.toPath(location);
+                        return locationPath === fileOrDirectoryPath || startsWith(resolutionHost.toPath(location), fileOrDirectoryPath);
+                    };
+                }
+                else {
+                    if (!isPathWithDefaultFailedLookupExtension(fileOrDirectoryPath) && !customFailedLookupPaths.has(fileOrDirectoryPath)) {
+                        return false;
+                    }
+                    // Resolution need to be invalidated if failed lookup location is same as the file or directory getting created
+                    isChangedFailedLookupLocation = location => resolutionHost.toPath(location) === fileOrDirectoryPath;
                 }
-                // Resolution need to be invalidated if failed lookup location is same as the file or directory getting created
-                isChangedFailedLookupLocation = location => resolutionHost.toPath(location) === fileOrDirectoryPath;
             }
             const hasChangedFailedLookupLocation = (resolution: ResolutionWithFailedLookupLocations) => some(resolution.failedLookupLocations, isChangedFailedLookupLocation);
             const invalidatedFilesCount = filesWithInvalidatedResolutions && filesWithInvalidatedResolutions.size;
diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
index 6dab127ca33..fd8c54a18cc 100644
--- a/src/compiler/scanner.ts
+++ b/src/compiler/scanner.ts
@@ -2,15 +2,18 @@
 /// <reference path="diagnosticInformationMap.generated.ts"/>
 
 namespace ts {
-    export interface ErrorCallback {
-        (message: DiagnosticMessage, length: number): void;
-    }
+    export type ErrorCallback = (message: DiagnosticMessage, length: number) => void;
 
     /* @internal */
     export function tokenIsIdentifierOrKeyword(token: SyntaxKind): boolean {
         return token >= SyntaxKind.Identifier;
     }
 
+    /* @internal */
+    export function tokenIsIdentifierOrKeywordOrGreaterThan(token: SyntaxKind): boolean {
+        return token === SyntaxKind.GreaterThanToken || tokenIsIdentifierOrKeyword(token);
+    }
+
     export interface Scanner {
         getStartPos(): number;
         getToken(): SyntaxKind;
@@ -352,7 +355,7 @@ namespace ts {
      * We assume the first line starts at position 0 and 'position' is non-negative.
      */
     export function computeLineAndCharacterOfPosition(lineStarts: ReadonlyArray<number>, position: number): LineAndCharacter {
-        let lineNumber = binarySearch(lineStarts, position);
+        let lineNumber = binarySearch(lineStarts, position, identity, compareValues);
         if (lineNumber < 0) {
             // If the actual position was not found,
             // the binary search returns the 2's-complement of the next line start
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 1169af191b8..529ece36fa6 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -124,7 +124,7 @@ namespace ts {
         getEnvironmentVariable?(name: string): string;
     };
 
-    export let sys: System = (function() {
+    export let sys: System = (() => {
         function getNodeSystem(): System {
             const _fs = require("fs");
             const _path = require("path");
@@ -511,7 +511,7 @@ namespace ts {
                             return stat.size;
                         }
                     }
-                    catch (e) { }
+                    catch { /*ignore*/ }
                     return 0;
                 },
                 exit(exitCode?: number): void {
@@ -525,7 +525,7 @@ namespace ts {
                     try {
                         require("source-map-support").install();
                     }
-                    catch (e) {
+                    catch {
                         // Could not enable source maps.
                     }
                 },
@@ -594,7 +594,7 @@ namespace ts {
         if (sys) {
             // patch writefile to create folder before writing the file
             const originalWriteFile = sys.writeFile;
-            sys.writeFile = function(path, data, writeBom) {
+            sys.writeFile = (path, data, writeBom) => {
                 const directoryPath = getDirectoryPath(normalizeSlashes(path));
                 if (directoryPath && !sys.directoryExists(directoryPath)) {
                     recursiveCreateDirectory(directoryPath, sys);
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
index a1e52480172..989b0827570 100644
--- a/src/compiler/transformers/es2015.ts
+++ b/src/compiler/transformers/es2015.ts
@@ -787,9 +787,7 @@ namespace ts {
             // To preserve the behavior of the old emitter, we explicitly indent
             // the body of the function here if it was requested in an earlier
             // transformation.
-            if (getEmitFlags(node) & EmitFlags.Indented) {
-                setEmitFlags(classFunction, EmitFlags.Indented);
-            }
+            setEmitFlags(classFunction, (getEmitFlags(node) & EmitFlags.Indented) | EmitFlags.ReuseTempVariableScope);
 
             // "inner" and "outer" below are added purely to preserve source map locations from
             // the old emitter
@@ -1327,7 +1325,8 @@ namespace ts {
                     EmitFlags.SingleLine | EmitFlags.NoTrailingSourceMap | EmitFlags.NoTokenSourceMaps
                 )
             );
-            statement.startsOnNewLine = true;
+
+            startOnNewLine(statement);
             setTextRange(statement, parameter);
             setEmitFlags(statement, EmitFlags.NoTokenSourceMaps | EmitFlags.NoTrailingSourceMap | EmitFlags.CustomPrologue);
             statements.push(statement);
@@ -1683,7 +1682,7 @@ namespace ts {
                 ]
             );
             if (startsOnNewLine) {
-                call.startsOnNewLine = true;
+                startOnNewLine(call);
             }
 
             exitSubtree(ancestorFacts, HierarchyFacts.PropagateNewTargetMask, hierarchyFacts & HierarchyFacts.PropagateNewTargetMask ? HierarchyFacts.NewTarget : HierarchyFacts.None);
@@ -2602,7 +2601,7 @@ namespace ts {
                 );
 
                 if (node.multiLine) {
-                    assignment.startsOnNewLine = true;
+                    startOnNewLine(assignment);
                 }
 
                 expressions.push(assignment);
@@ -3083,7 +3082,7 @@ namespace ts {
             );
             setTextRange(expression, property);
             if (startsOnNewLine) {
-                expression.startsOnNewLine = true;
+                startOnNewLine(expression);
             }
             return expression;
         }
@@ -3105,7 +3104,7 @@ namespace ts {
             );
             setTextRange(expression, property);
             if (startsOnNewLine) {
-                expression.startsOnNewLine = true;
+                startOnNewLine(expression);
             }
             return expression;
         }
@@ -3128,7 +3127,7 @@ namespace ts {
             );
             setTextRange(expression, method);
             if (startsOnNewLine) {
-                expression.startsOnNewLine = true;
+                startOnNewLine(expression);
             }
             exitSubtree(ancestorFacts, HierarchyFacts.PropagateNewTargetMask, hierarchyFacts & HierarchyFacts.PropagateNewTargetMask ? HierarchyFacts.NewTarget : HierarchyFacts.None);
             return expression;
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index 7ede62b1540..bd2a4ef554d 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -1077,7 +1077,7 @@ namespace ts {
                 const visited = visitNode(expression, visitor, isExpression);
                 if (visited) {
                     if (multiLine) {
-                        visited.startsOnNewLine = true;
+                        startOnNewLine(visited);
                     }
                     expressions.push(visited);
                 }
@@ -2683,8 +2683,7 @@ namespace ts {
             if (clauses) {
                 const labelExpression = createPropertyAccess(state, "label");
                 const switchStatement = createSwitch(labelExpression, createCaseBlock(clauses));
-                switchStatement.startsOnNewLine = true;
-                return [switchStatement];
+                return [startOnNewLine(switchStatement)];
             }
 
             if (statements) {
diff --git a/src/compiler/transformers/jsx.ts b/src/compiler/transformers/jsx.ts
index bbe05afe878..ab44db8ef4b 100644
--- a/src/compiler/transformers/jsx.ts
+++ b/src/compiler/transformers/jsx.ts
@@ -41,6 +41,9 @@ namespace ts {
                 case SyntaxKind.JsxSelfClosingElement:
                     return visitJsxSelfClosingElement(<JsxSelfClosingElement>node, /*isChild*/ false);
 
+                case SyntaxKind.JsxFragment:
+                    return visitJsxFragment(<JsxFragment>node, /*isChild*/ false);
+
                 case SyntaxKind.JsxExpression:
                     return visitJsxExpression(<JsxExpression>node);
 
@@ -63,6 +66,9 @@ namespace ts {
                 case SyntaxKind.JsxSelfClosingElement:
                     return visitJsxSelfClosingElement(<JsxSelfClosingElement>node, /*isChild*/ true);
 
+                case SyntaxKind.JsxFragment:
+                    return visitJsxFragment(<JsxFragment>node, /*isChild*/ true);
+
                 default:
                     Debug.failBadSyntaxKind(node);
                     return undefined;
@@ -77,6 +83,10 @@ namespace ts {
             return visitJsxOpeningLikeElement(node, /*children*/ undefined, isChild, /*location*/ node);
         }
 
+        function visitJsxFragment(node: JsxFragment, isChild: boolean) {
+            return visitJsxOpeningFragment(node.openingFragment, node.children, isChild, /*location*/ node);
+        }
+
         function visitJsxOpeningLikeElement(node: JsxOpeningLikeElement, children: ReadonlyArray<JsxChild>, isChild: boolean, location: TextRange) {
             const tagName = getTagName(node);
             let objectProperties: Expression;
@@ -126,6 +136,22 @@ namespace ts {
             return element;
         }
 
+        function visitJsxOpeningFragment(node: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, isChild: boolean, location: TextRange) {
+            const element = createExpressionForJsxFragment(
+                context.getEmitResolver().getJsxFactoryEntity(),
+                compilerOptions.reactNamespace,
+                mapDefined(children, transformJsxChildToExpression),
+                node,
+                location
+            );
+
+            if (isChild) {
+                startOnNewLine(element);
+            }
+
+            return element;
+        }
+
         function transformJsxSpreadAttributeToExpression(node: JsxSpreadAttribute) {
             return visitNode(node.expression, visitor, isExpression);
         }
@@ -283,258 +309,258 @@ namespace ts {
     }
 
     const entities = createMapFromTemplate<number>({
-        "quot": 0x0022,
-        "amp": 0x0026,
-        "apos": 0x0027,
-        "lt": 0x003C,
-        "gt": 0x003E,
-        "nbsp": 0x00A0,
-        "iexcl": 0x00A1,
-        "cent": 0x00A2,
-        "pound": 0x00A3,
-        "curren": 0x00A4,
-        "yen": 0x00A5,
-        "brvbar": 0x00A6,
-        "sect": 0x00A7,
-        "uml": 0x00A8,
-        "copy": 0x00A9,
-        "ordf": 0x00AA,
-        "laquo": 0x00AB,
-        "not": 0x00AC,
-        "shy": 0x00AD,
-        "reg": 0x00AE,
-        "macr": 0x00AF,
-        "deg": 0x00B0,
-        "plusmn": 0x00B1,
-        "sup2": 0x00B2,
-        "sup3": 0x00B3,
-        "acute": 0x00B4,
-        "micro": 0x00B5,
-        "para": 0x00B6,
-        "middot": 0x00B7,
-        "cedil": 0x00B8,
-        "sup1": 0x00B9,
-        "ordm": 0x00BA,
-        "raquo": 0x00BB,
-        "frac14": 0x00BC,
-        "frac12": 0x00BD,
-        "frac34": 0x00BE,
-        "iquest": 0x00BF,
-        "Agrave": 0x00C0,
-        "Aacute": 0x00C1,
-        "Acirc": 0x00C2,
-        "Atilde": 0x00C3,
-        "Auml": 0x00C4,
-        "Aring": 0x00C5,
-        "AElig": 0x00C6,
-        "Ccedil": 0x00C7,
-        "Egrave": 0x00C8,
-        "Eacute": 0x00C9,
-        "Ecirc": 0x00CA,
-        "Euml": 0x00CB,
-        "Igrave": 0x00CC,
-        "Iacute": 0x00CD,
-        "Icirc": 0x00CE,
-        "Iuml": 0x00CF,
-        "ETH": 0x00D0,
-        "Ntilde": 0x00D1,
-        "Ograve": 0x00D2,
-        "Oacute": 0x00D3,
-        "Ocirc": 0x00D4,
-        "Otilde": 0x00D5,
-        "Ouml": 0x00D6,
-        "times": 0x00D7,
-        "Oslash": 0x00D8,
-        "Ugrave": 0x00D9,
-        "Uacute": 0x00DA,
-        "Ucirc": 0x00DB,
-        "Uuml": 0x00DC,
-        "Yacute": 0x00DD,
-        "THORN": 0x00DE,
-        "szlig": 0x00DF,
-        "agrave": 0x00E0,
-        "aacute": 0x00E1,
-        "acirc": 0x00E2,
-        "atilde": 0x00E3,
-        "auml": 0x00E4,
-        "aring": 0x00E5,
-        "aelig": 0x00E6,
-        "ccedil": 0x00E7,
-        "egrave": 0x00E8,
-        "eacute": 0x00E9,
-        "ecirc": 0x00EA,
-        "euml": 0x00EB,
-        "igrave": 0x00EC,
-        "iacute": 0x00ED,
-        "icirc": 0x00EE,
-        "iuml": 0x00EF,
-        "eth": 0x00F0,
-        "ntilde": 0x00F1,
-        "ograve": 0x00F2,
-        "oacute": 0x00F3,
-        "ocirc": 0x00F4,
-        "otilde": 0x00F5,
-        "ouml": 0x00F6,
-        "divide": 0x00F7,
-        "oslash": 0x00F8,
-        "ugrave": 0x00F9,
-        "uacute": 0x00FA,
-        "ucirc": 0x00FB,
-        "uuml": 0x00FC,
-        "yacute": 0x00FD,
-        "thorn": 0x00FE,
-        "yuml": 0x00FF,
-        "OElig": 0x0152,
-        "oelig": 0x0153,
-        "Scaron": 0x0160,
-        "scaron": 0x0161,
-        "Yuml": 0x0178,
-        "fnof": 0x0192,
-        "circ": 0x02C6,
-        "tilde": 0x02DC,
-        "Alpha": 0x0391,
-        "Beta": 0x0392,
-        "Gamma": 0x0393,
-        "Delta": 0x0394,
-        "Epsilon": 0x0395,
-        "Zeta": 0x0396,
-        "Eta": 0x0397,
-        "Theta": 0x0398,
-        "Iota": 0x0399,
-        "Kappa": 0x039A,
-        "Lambda": 0x039B,
-        "Mu": 0x039C,
-        "Nu": 0x039D,
-        "Xi": 0x039E,
-        "Omicron": 0x039F,
-        "Pi": 0x03A0,
-        "Rho": 0x03A1,
-        "Sigma": 0x03A3,
-        "Tau": 0x03A4,
-        "Upsilon": 0x03A5,
-        "Phi": 0x03A6,
-        "Chi": 0x03A7,
-        "Psi": 0x03A8,
-        "Omega": 0x03A9,
-        "alpha": 0x03B1,
-        "beta": 0x03B2,
-        "gamma": 0x03B3,
-        "delta": 0x03B4,
-        "epsilon": 0x03B5,
-        "zeta": 0x03B6,
-        "eta": 0x03B7,
-        "theta": 0x03B8,
-        "iota": 0x03B9,
-        "kappa": 0x03BA,
-        "lambda": 0x03BB,
-        "mu": 0x03BC,
-        "nu": 0x03BD,
-        "xi": 0x03BE,
-        "omicron": 0x03BF,
-        "pi": 0x03C0,
-        "rho": 0x03C1,
-        "sigmaf": 0x03C2,
-        "sigma": 0x03C3,
-        "tau": 0x03C4,
-        "upsilon": 0x03C5,
-        "phi": 0x03C6,
-        "chi": 0x03C7,
-        "psi": 0x03C8,
-        "omega": 0x03C9,
-        "thetasym": 0x03D1,
-        "upsih": 0x03D2,
-        "piv": 0x03D6,
-        "ensp": 0x2002,
-        "emsp": 0x2003,
-        "thinsp": 0x2009,
-        "zwnj": 0x200C,
-        "zwj": 0x200D,
-        "lrm": 0x200E,
-        "rlm": 0x200F,
-        "ndash": 0x2013,
-        "mdash": 0x2014,
-        "lsquo": 0x2018,
-        "rsquo": 0x2019,
-        "sbquo": 0x201A,
-        "ldquo": 0x201C,
-        "rdquo": 0x201D,
-        "bdquo": 0x201E,
-        "dagger": 0x2020,
-        "Dagger": 0x2021,
-        "bull": 0x2022,
-        "hellip": 0x2026,
-        "permil": 0x2030,
-        "prime": 0x2032,
-        "Prime": 0x2033,
-        "lsaquo": 0x2039,
-        "rsaquo": 0x203A,
-        "oline": 0x203E,
-        "frasl": 0x2044,
-        "euro": 0x20AC,
-        "image": 0x2111,
-        "weierp": 0x2118,
-        "real": 0x211C,
-        "trade": 0x2122,
-        "alefsym": 0x2135,
-        "larr": 0x2190,
-        "uarr": 0x2191,
-        "rarr": 0x2192,
-        "darr": 0x2193,
-        "harr": 0x2194,
-        "crarr": 0x21B5,
-        "lArr": 0x21D0,
-        "uArr": 0x21D1,
-        "rArr": 0x21D2,
-        "dArr": 0x21D3,
-        "hArr": 0x21D4,
-        "forall": 0x2200,
-        "part": 0x2202,
-        "exist": 0x2203,
-        "empty": 0x2205,
-        "nabla": 0x2207,
-        "isin": 0x2208,
-        "notin": 0x2209,
-        "ni": 0x220B,
-        "prod": 0x220F,
-        "sum": 0x2211,
-        "minus": 0x2212,
-        "lowast": 0x2217,
-        "radic": 0x221A,
-        "prop": 0x221D,
-        "infin": 0x221E,
-        "ang": 0x2220,
-        "and": 0x2227,
-        "or": 0x2228,
-        "cap": 0x2229,
-        "cup": 0x222A,
-        "int": 0x222B,
-        "there4": 0x2234,
-        "sim": 0x223C,
-        "cong": 0x2245,
-        "asymp": 0x2248,
-        "ne": 0x2260,
-        "equiv": 0x2261,
-        "le": 0x2264,
-        "ge": 0x2265,
-        "sub": 0x2282,
-        "sup": 0x2283,
-        "nsub": 0x2284,
-        "sube": 0x2286,
-        "supe": 0x2287,
-        "oplus": 0x2295,
-        "otimes": 0x2297,
-        "perp": 0x22A5,
-        "sdot": 0x22C5,
-        "lceil": 0x2308,
-        "rceil": 0x2309,
-        "lfloor": 0x230A,
-        "rfloor": 0x230B,
-        "lang": 0x2329,
-        "rang": 0x232A,
-        "loz": 0x25CA,
-        "spades": 0x2660,
-        "clubs": 0x2663,
-        "hearts": 0x2665,
-        "diams": 0x2666
+        quot: 0x0022,
+        amp: 0x0026,
+        apos: 0x0027,
+        lt: 0x003C,
+        gt: 0x003E,
+        nbsp: 0x00A0,
+        iexcl: 0x00A1,
+        cent: 0x00A2,
+        pound: 0x00A3,
+        curren: 0x00A4,
+        yen: 0x00A5,
+        brvbar: 0x00A6,
+        sect: 0x00A7,
+        uml: 0x00A8,
+        copy: 0x00A9,
+        ordf: 0x00AA,
+        laquo: 0x00AB,
+        not: 0x00AC,
+        shy: 0x00AD,
+        reg: 0x00AE,
+        macr: 0x00AF,
+        deg: 0x00B0,
+        plusmn: 0x00B1,
+        sup2: 0x00B2,
+        sup3: 0x00B3,
+        acute: 0x00B4,
+        micro: 0x00B5,
+        para: 0x00B6,
+        middot: 0x00B7,
+        cedil: 0x00B8,
+        sup1: 0x00B9,
+        ordm: 0x00BA,
+        raquo: 0x00BB,
+        frac14: 0x00BC,
+        frac12: 0x00BD,
+        frac34: 0x00BE,
+        iquest: 0x00BF,
+        Agrave: 0x00C0,
+        Aacute: 0x00C1,
+        Acirc: 0x00C2,
+        Atilde: 0x00C3,
+        Auml: 0x00C4,
+        Aring: 0x00C5,
+        AElig: 0x00C6,
+        Ccedil: 0x00C7,
+        Egrave: 0x00C8,
+        Eacute: 0x00C9,
+        Ecirc: 0x00CA,
+        Euml: 0x00CB,
+        Igrave: 0x00CC,
+        Iacute: 0x00CD,
+        Icirc: 0x00CE,
+        Iuml: 0x00CF,
+        ETH: 0x00D0,
+        Ntilde: 0x00D1,
+        Ograve: 0x00D2,
+        Oacute: 0x00D3,
+        Ocirc: 0x00D4,
+        Otilde: 0x00D5,
+        Ouml: 0x00D6,
+        times: 0x00D7,
+        Oslash: 0x00D8,
+        Ugrave: 0x00D9,
+        Uacute: 0x00DA,
+        Ucirc: 0x00DB,
+        Uuml: 0x00DC,
+        Yacute: 0x00DD,
+        THORN: 0x00DE,
+        szlig: 0x00DF,
+        agrave: 0x00E0,
+        aacute: 0x00E1,
+        acirc: 0x00E2,
+        atilde: 0x00E3,
+        auml: 0x00E4,
+        aring: 0x00E5,
+        aelig: 0x00E6,
+        ccedil: 0x00E7,
+        egrave: 0x00E8,
+        eacute: 0x00E9,
+        ecirc: 0x00EA,
+        euml: 0x00EB,
+        igrave: 0x00EC,
+        iacute: 0x00ED,
+        icirc: 0x00EE,
+        iuml: 0x00EF,
+        eth: 0x00F0,
+        ntilde: 0x00F1,
+        ograve: 0x00F2,
+        oacute: 0x00F3,
+        ocirc: 0x00F4,
+        otilde: 0x00F5,
+        ouml: 0x00F6,
+        divide: 0x00F7,
+        oslash: 0x00F8,
+        ugrave: 0x00F9,
+        uacute: 0x00FA,
+        ucirc: 0x00FB,
+        uuml: 0x00FC,
+        yacute: 0x00FD,
+        thorn: 0x00FE,
+        yuml: 0x00FF,
+        OElig: 0x0152,
+        oelig: 0x0153,
+        Scaron: 0x0160,
+        scaron: 0x0161,
+        Yuml: 0x0178,
+        fnof: 0x0192,
+        circ: 0x02C6,
+        tilde: 0x02DC,
+        Alpha: 0x0391,
+        Beta: 0x0392,
+        Gamma: 0x0393,
+        Delta: 0x0394,
+        Epsilon: 0x0395,
+        Zeta: 0x0396,
+        Eta: 0x0397,
+        Theta: 0x0398,
+        Iota: 0x0399,
+        Kappa: 0x039A,
+        Lambda: 0x039B,
+        Mu: 0x039C,
+        Nu: 0x039D,
+        Xi: 0x039E,
+        Omicron: 0x039F,
+        Pi: 0x03A0,
+        Rho: 0x03A1,
+        Sigma: 0x03A3,
+        Tau: 0x03A4,
+        Upsilon: 0x03A5,
+        Phi: 0x03A6,
+        Chi: 0x03A7,
+        Psi: 0x03A8,
+        Omega: 0x03A9,
+        alpha: 0x03B1,
+        beta: 0x03B2,
+        gamma: 0x03B3,
+        delta: 0x03B4,
+        epsilon: 0x03B5,
+        zeta: 0x03B6,
+        eta: 0x03B7,
+        theta: 0x03B8,
+        iota: 0x03B9,
+        kappa: 0x03BA,
+        lambda: 0x03BB,
+        mu: 0x03BC,
+        nu: 0x03BD,
+        xi: 0x03BE,
+        omicron: 0x03BF,
+        pi: 0x03C0,
+        rho: 0x03C1,
+        sigmaf: 0x03C2,
+        sigma: 0x03C3,
+        tau: 0x03C4,
+        upsilon: 0x03C5,
+        phi: 0x03C6,
+        chi: 0x03C7,
+        psi: 0x03C8,
+        omega: 0x03C9,
+        thetasym: 0x03D1,
+        upsih: 0x03D2,
+        piv: 0x03D6,
+        ensp: 0x2002,
+        emsp: 0x2003,
+        thinsp: 0x2009,
+        zwnj: 0x200C,
+        zwj: 0x200D,
+        lrm: 0x200E,
+        rlm: 0x200F,
+        ndash: 0x2013,
+        mdash: 0x2014,
+        lsquo: 0x2018,
+        rsquo: 0x2019,
+        sbquo: 0x201A,
+        ldquo: 0x201C,
+        rdquo: 0x201D,
+        bdquo: 0x201E,
+        dagger: 0x2020,
+        Dagger: 0x2021,
+        bull: 0x2022,
+        hellip: 0x2026,
+        permil: 0x2030,
+        prime: 0x2032,
+        Prime: 0x2033,
+        lsaquo: 0x2039,
+        rsaquo: 0x203A,
+        oline: 0x203E,
+        frasl: 0x2044,
+        euro: 0x20AC,
+        image: 0x2111,
+        weierp: 0x2118,
+        real: 0x211C,
+        trade: 0x2122,
+        alefsym: 0x2135,
+        larr: 0x2190,
+        uarr: 0x2191,
+        rarr: 0x2192,
+        darr: 0x2193,
+        harr: 0x2194,
+        crarr: 0x21B5,
+        lArr: 0x21D0,
+        uArr: 0x21D1,
+        rArr: 0x21D2,
+        dArr: 0x21D3,
+        hArr: 0x21D4,
+        forall: 0x2200,
+        part: 0x2202,
+        exist: 0x2203,
+        empty: 0x2205,
+        nabla: 0x2207,
+        isin: 0x2208,
+        notin: 0x2209,
+        ni: 0x220B,
+        prod: 0x220F,
+        sum: 0x2211,
+        minus: 0x2212,
+        lowast: 0x2217,
+        radic: 0x221A,
+        prop: 0x221D,
+        infin: 0x221E,
+        ang: 0x2220,
+        and: 0x2227,
+        or: 0x2228,
+        cap: 0x2229,
+        cup: 0x222A,
+        int: 0x222B,
+        there4: 0x2234,
+        sim: 0x223C,
+        cong: 0x2245,
+        asymp: 0x2248,
+        ne: 0x2260,
+        equiv: 0x2261,
+        le: 0x2264,
+        ge: 0x2265,
+        sub: 0x2282,
+        sup: 0x2283,
+        nsub: 0x2284,
+        sube: 0x2286,
+        supe: 0x2287,
+        oplus: 0x2295,
+        otimes: 0x2297,
+        perp: 0x22A5,
+        sdot: 0x22C5,
+        lceil: 0x2308,
+        rceil: 0x2309,
+        lfloor: 0x230A,
+        rfloor: 0x230B,
+        lang: 0x2329,
+        rang: 0x232A,
+        loz: 0x25CA,
+        spades: 0x2660,
+        clubs: 0x2663,
+        hearts: 0x2665,
+        diams: 0x2666
     });
 }
\ No newline at end of file
diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
index bd360fdffe4..f60e50ea365 100644
--- a/src/compiler/transformers/module/module.ts
+++ b/src/compiler/transformers/module/module.ts
@@ -91,7 +91,7 @@ namespace ts {
             startLexicalEnvironment();
 
             const statements: Statement[] = [];
-            const ensureUseStrict = compilerOptions.alwaysStrict || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
+            const ensureUseStrict = getStrictOptionValue(compilerOptions, "alwaysStrict") || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
             const statementOffset = addPrologue(statements, node.statements, ensureUseStrict, sourceElementVisitor);
 
             if (shouldEmitUnderscoreUnderscoreESModule()) {
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
index d674546efb9..e5d638cf04d 100644
--- a/src/compiler/transformers/module/system.ts
+++ b/src/compiler/transformers/module/system.ts
@@ -146,8 +146,7 @@ namespace ts {
         function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
             const groupIndices = createMap<number>();
             const dependencyGroups: DependencyGroup[] = [];
-            for (let i = 0; i < externalImports.length; i++) {
-                const externalImport = externalImports[i];
+            for (const externalImport of externalImports) {
                 const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
                 if (externalModuleName) {
                     const text = externalModuleName.text;
@@ -225,7 +224,7 @@ namespace ts {
             startLexicalEnvironment();
 
             // Add any prologue directives.
-            const ensureUseStrict = compilerOptions.alwaysStrict || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
+            const ensureUseStrict = getStrictOptionValue(compilerOptions, "alwaysStrict") || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
             const statementOffset = addPrologue(statements, node.statements, ensureUseStrict, sourceElementVisitor);
 
             // var __moduleName = context_1 && context_1.id;
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index ba4b5fcdf52..39a4cc83bda 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -45,7 +45,7 @@ namespace ts {
 
         const resolver = context.getEmitResolver();
         const compilerOptions = context.getCompilerOptions();
-        const strictNullChecks = typeof compilerOptions.strictNullChecks === "undefined" ? compilerOptions.strict : compilerOptions.strictNullChecks;
+        const strictNullChecks = getStrictOptionValue(compilerOptions, "strictNullChecks");
         const languageVersion = getEmitScriptTarget(compilerOptions);
         const moduleKind = getEmitModuleKind(compilerOptions);
 
@@ -86,6 +86,12 @@ namespace ts {
          */
         let applicableSubstitutions: TypeScriptSubstitutionFlags;
 
+        /**
+         * Tracks what computed name expressions originating from elided names must be inlined
+         * at the next execution site, in document order
+         */
+        let pendingExpressions: Expression[] | undefined;
+
         return transformSourceFile;
 
         /**
@@ -225,6 +231,13 @@ namespace ts {
             if (parsed !== node) {
                 // If the node has been transformed by a `before` transformer, perform no ellision on it
                 // As the type information we would attempt to lookup to perform ellision is potentially unavailable for the synthesized nodes
+                // We do not reuse `visitorWorker`, as the ellidable statement syntax kinds are technically unrecognized by the switch-case in `visitTypeScript`,
+                // and will trigger debug failures when debug verbosity is turned up
+                if (node.transformFlags & TransformFlags.ContainsTypeScript) {
+                    // This node contains TypeScript, so we should visit its children.
+                    return visitEachChild(node, visitor, context);
+                }
+                // Otherwise, we can just return the node
                 return node;
             }
             switch (node.kind) {
@@ -388,9 +401,11 @@ namespace ts {
 
                 case SyntaxKind.TypeAliasDeclaration:
                     // TypeScript type-only declarations are elided.
+                    return undefined;
 
                 case SyntaxKind.PropertyDeclaration:
-                    // TypeScript property declarations are elided.
+                    // TypeScript property declarations are elided. However their names are still visited, and can potentially be retained if they could have sideeffects
+                    return visitPropertyDeclaration(node as PropertyDeclaration);
 
                 case SyntaxKind.NamespaceExportDeclaration:
                     // TypeScript namespace export declarations are elided.
@@ -521,7 +536,7 @@ namespace ts {
         }
 
         function visitSourceFile(node: SourceFile) {
-            const alwaysStrict = (compilerOptions.alwaysStrict === undefined ? compilerOptions.strict : compilerOptions.alwaysStrict) &&
+            const alwaysStrict = getStrictOptionValue(compilerOptions, "alwaysStrict") &&
                 !(isExternalModule(node) && moduleKind >= ModuleKind.ES2015);
             return updateSourceFileNode(
                 node,
@@ -577,6 +592,9 @@ namespace ts {
          * @param node The node to transform.
          */
         function visitClassDeclaration(node: ClassDeclaration): VisitResult<Statement> {
+            const savedPendingExpressions = pendingExpressions;
+            pendingExpressions = undefined;
+
             const staticProperties = getInitializedProperties(node, /*isStatic*/ true);
             const facts = getClassFacts(node, staticProperties);
 
@@ -591,6 +609,12 @@ namespace ts {
 
             let statements: Statement[] = [classStatement];
 
+            // Write any pending expressions from elided or moved computed property names
+            if (some(pendingExpressions)) {
+                statements.push(createStatement(inlineExpressions(pendingExpressions)));
+            }
+            pendingExpressions = savedPendingExpressions;
+
             // Emit static property assignment. Because classDeclaration is lexically evaluated,
             // it is safe to emit static property assignment after classDeclaration
             // From ES6 specification:
@@ -849,6 +873,9 @@ namespace ts {
          * @param node The node to transform.
          */
         function visitClassExpression(node: ClassExpression): Expression {
+            const savedPendingExpressions = pendingExpressions;
+            pendingExpressions = undefined;
+
             const staticProperties = getInitializedProperties(node, /*isStatic*/ true);
             const heritageClauses = visitNodes(node.heritageClauses, visitor, isHeritageClause);
             const members = transformClassMembers(node, some(heritageClauses, c => c.token === SyntaxKind.ExtendsKeyword));
@@ -864,7 +891,7 @@ namespace ts {
             setOriginalNode(classExpression, node);
             setTextRange(classExpression, node);
 
-            if (staticProperties.length > 0) {
+            if (some(staticProperties) || some(pendingExpressions)) {
                 const expressions: Expression[] = [];
                 const temp = createTempVariable(hoistVariableDeclaration);
                 if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithConstructorReference) {
@@ -877,11 +904,15 @@ namespace ts {
                 // the body of a class with static initializers.
                 setEmitFlags(classExpression, EmitFlags.Indented | getEmitFlags(classExpression));
                 expressions.push(startOnNewLine(createAssignment(temp, classExpression)));
+                // Add any pending expressions leftover from elided or relocated computed property names
+                addRange(expressions, map(pendingExpressions, startOnNewLine));
+                pendingExpressions = savedPendingExpressions;
                 addRange(expressions, generateInitializedPropertyExpressions(staticProperties, temp));
                 expressions.push(startOnNewLine(temp));
                 return inlineExpressions(expressions);
             }
 
+            pendingExpressions = savedPendingExpressions;
             return classExpression;
         }
 
@@ -1195,7 +1226,7 @@ namespace ts {
             const expressions: Expression[] = [];
             for (const property of properties) {
                 const expression = transformInitializedProperty(property, receiver);
-                expression.startsOnNewLine = true;
+                startOnNewLine(expression);
                 setSourceMapRange(expression, moveRangePastModifiers(property));
                 setCommentRange(expression, property);
                 expressions.push(expression);
@@ -1211,7 +1242,10 @@ namespace ts {
          * @param receiver The object receiving the property assignment.
          */
         function transformInitializedProperty(property: PropertyDeclaration, receiver: LeftHandSideExpression) {
-            const propertyName = visitPropertyNameOfClassElement(property);
+            // We generate a name here in order to reuse the value cached by the relocated computed name expression (which uses the same generated name)
+            const propertyName = isComputedPropertyName(property.name) && !isSimpleInlineableExpression(property.name.expression)
+                ? updateComputedPropertyName(property.name, getGeneratedNameForNode(property.name, !hasModifier(property, ModifierFlags.Static)))
+                : property.name;
             const initializer = visitNode(property.initializer, visitor, isExpression);
             const memberAccess = createMemberAccessForPropertyName(receiver, propertyName, /*location*/ propertyName);
 
@@ -2034,6 +2068,16 @@ namespace ts {
             );
         }
 
+        /**
+         * A simple inlinable expression is an expression which can be copied into multiple locations
+         * without risk of repeating any sideeffects and whose value could not possibly change between
+         * any such locations
+         */
+        function isSimpleInlineableExpression(expression: Expression) {
+            return !isIdentifier(expression) && isSimpleCopiableExpression(expression) ||
+                isWellKnownSymbolSyntactically(expression);
+        }
+
         /**
          * Gets an expression that represents a property name. For a computed property, a
          * name is generated for the node.
@@ -2043,7 +2087,7 @@ namespace ts {
         function getExpressionForPropertyName(member: ClassElement | EnumMember, generateNameForComputedPropertyName: boolean): Expression {
             const name = member.name;
             if (isComputedPropertyName(name)) {
-                return generateNameForComputedPropertyName
+                return generateNameForComputedPropertyName && !isSimpleInlineableExpression((<ComputedPropertyName>name).expression)
                     ? getGeneratedNameForNode(name)
                     : (<ComputedPropertyName>name).expression;
             }
@@ -2055,6 +2099,26 @@ namespace ts {
             }
         }
 
+        /**
+         * If the name is a computed property, this function transforms it, then either returns an expression which caches the
+         * value of the result or the expression itself if the value is either unused or safe to inline into multiple locations
+         * @param shouldHoist Does the expression need to be reused? (ie, for an initializer or a decorator)
+         * @param omitSimple Should expressions with no observable side-effects be elided? (ie, the expression is not hoisted for a decorator or initializer and is a literal)
+         */
+        function getPropertyNameExpressionIfNeeded(name: PropertyName, shouldHoist: boolean, omitSimple: boolean): Expression {
+            if (isComputedPropertyName(name)) {
+                const expression = visitNode(name.expression, visitor, isExpression);
+                const innerExpression = skipPartiallyEmittedExpressions(expression);
+                const inlinable = isSimpleInlineableExpression(innerExpression);
+                if (!inlinable && shouldHoist) {
+                    const generatedName = getGeneratedNameForNode(name);
+                    hoistVariableDeclaration(generatedName);
+                    return createAssignment(generatedName, expression);
+                }
+                return (omitSimple && (inlinable || isIdentifier(innerExpression))) ? undefined : expression;
+            }
+        }
+
         /**
          * Visits the property name of a class element, for use when emitting property
          * initializers. For a computed property on a node with decorators, a temporary
@@ -2064,15 +2128,14 @@ namespace ts {
          */
         function visitPropertyNameOfClassElement(member: ClassElement): PropertyName {
             const name = member.name;
-            if (isComputedPropertyName(name)) {
-                let expression = visitNode(name.expression, visitor, isExpression);
-                if (member.decorators) {
-                    const generatedName = getGeneratedNameForNode(name);
-                    hoistVariableDeclaration(generatedName);
-                    expression = createAssignment(generatedName, expression);
+            let expr = getPropertyNameExpressionIfNeeded(name, some(member.decorators), /*omitSimple*/ false);
+            if (expr) { // expr only exists if `name` is a computed property name
+                // Inline any pending expressions from previous elided or relocated computed property name expressions in order to preserve execution order
+                if (some(pendingExpressions)) {
+                    expr = inlineExpressions([...pendingExpressions, expr]);
+                    pendingExpressions.length = 0;
                 }
-
-                return updateComputedPropertyName(name, expression);
+                return updateComputedPropertyName(name as ComputedPropertyName, expr);
             }
             else {
                 return name;
@@ -2129,6 +2192,14 @@ namespace ts {
             return !nodeIsMissing(node.body);
         }
 
+        function visitPropertyDeclaration(node: PropertyDeclaration): undefined {
+            const expr = getPropertyNameExpressionIfNeeded(node.name, some(node.decorators) || !!node.initializer, /*omitSimple*/ true);
+            if (expr && !isSimpleInlineableExpression(expr)) {
+                (pendingExpressions || (pendingExpressions = [])).push(expr);
+            }
+            return undefined;
+        }
+
         function visitConstructor(node: ConstructorDeclaration) {
             if (!shouldEmitFunctionLikeDeclaration(node)) {
                 return undefined;
@@ -2149,7 +2220,7 @@ namespace ts {
          * This function will be called when one of the following conditions are met:
          * - The node is an overload
          * - The node is marked as abstract, public, private, protected, or readonly
-         * - The node has both a decorator and a computed property name
+         * - The node has a computed property name
          *
          * @param node The method node.
          */
@@ -2193,7 +2264,7 @@ namespace ts {
          *
          * This function will be called when one of the following conditions are met:
          * - The node is marked as abstract, public, private, or protected
-         * - The node has both a decorator and a computed property name
+         * - The node has a computed property name
          *
          * @param node The get accessor node.
          */
@@ -2224,7 +2295,7 @@ namespace ts {
          *
          * This function will be called when one of the following conditions are met:
          * - The node is marked as abstract, public, private, or protected
-         * - The node has both a decorator and a computed property name
+         * - The node has a computed property name
          *
          * @param node The set accessor node.
          */
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index 680daeeb485..01fb45e4f7d 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -43,20 +43,12 @@ namespace ts {
         return s;
     }
 
-    function isJSONSupported() {
-        return typeof JSON === "object" && typeof JSON.parse === "function";
-    }
-
     export function executeCommandLine(args: string[]): void {
         const commandLine = parseCommandLine(args);
 
         // Configuration file name (if any)
         let configFileName: string;
         if (commandLine.options.locale) {
-            if (!isJSONSupported()) {
-                reportDiagnostic(createCompilerDiagnostic(Diagnostics.The_current_host_does_not_support_the_0_option, "--locale"));
-                return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
-            }
             validateLocaleAndSetLanguage(commandLine.options.locale, sys, commandLine.errors);
         }
 
@@ -84,10 +76,6 @@ namespace ts {
         }
 
         if (commandLine.options.project) {
-            if (!isJSONSupported()) {
-                reportDiagnostic(createCompilerDiagnostic(Diagnostics.The_current_host_does_not_support_the_0_option, "--project"));
-                return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
-            }
             if (commandLine.fileNames.length !== 0) {
                 reportDiagnostic(createCompilerDiagnostic(Diagnostics.Option_project_cannot_be_mixed_with_source_files_on_a_command_line));
                 return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
@@ -109,7 +97,7 @@ namespace ts {
                 }
             }
         }
-        else if (commandLine.fileNames.length === 0 && isJSONSupported()) {
+        else if (commandLine.fileNames.length === 0) {
             const searchPath = normalizePath(sys.getCurrentDirectory());
             configFileName = findConfigFile(searchPath, sys.fileExists);
         }
@@ -306,7 +294,7 @@ namespace ts {
 
         // Sort our options by their names, (e.g. "--noImplicitAny" comes before "--watch")
         const optsList = showAllOptions ?
-            optionDeclarations.slice().sort((a, b) => compareValues<string>(a.name.toLowerCase(), b.name.toLowerCase())) :
+            sort(optionDeclarations, (a, b) => compareStringsCaseInsensitive(a.name, b.name)) :
             filter(optionDeclarations.slice(), v => v.showInSimplifiedHelpView);
 
         // We want our descriptions to align at the same column in our output,
@@ -317,9 +305,7 @@ namespace ts {
 
         const optionsDescriptionMap = createMap<string[]>();  // Map between option.description and list of option.type if it is a kind
 
-        for (let i = 0; i < optsList.length; i++) {
-            const option = optsList[i];
-
+        for (const option of optsList) {
             // If an option lacks a description,
             // it is not officially supported.
             if (!option.description) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index ff2a33266ed..d2107572ab4 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -36,6 +36,19 @@ namespace ts {
         push(...values: T[]): void;
     }
 
+    /* @internal */
+    export type EqualityComparer<T> = (a: T, b: T) => boolean;
+
+    /* @internal */
+    export type Comparer<T> = (a: T, b: T) => Comparison;
+
+    /* @internal */
+    export const enum Comparison {
+        LessThan    = -1,
+        EqualTo     = 0,
+        GreaterThan = 1
+    }
+
     // branded string type used to store absolute, normalized and canonicalized paths
     // arbitrary file name can be converted to Path via toPath function
     export type Path = string & { __pathBrand: any };
@@ -328,6 +341,9 @@ namespace ts {
         JsxSelfClosingElement,
         JsxOpeningElement,
         JsxClosingElement,
+        JsxFragment,
+        JsxOpeningFragment,
+        JsxClosingFragment,
         JsxAttribute,
         JsxAttributes,
         JsxSpreadAttribute,
@@ -362,6 +378,7 @@ namespace ts {
         JSDocFunctionType,
         JSDocVariadicType,
         JSDocComment,
+        JSDocTypeLiteral,
         JSDocTag,
         JSDocAugmentsTag,
         JSDocClassTag,
@@ -371,7 +388,6 @@ namespace ts {
         JSDocTemplateTag,
         JSDocTypedefTag,
         JSDocPropertyTag,
-        JSDocTypeLiteral,
 
         // Synthesized list
         SyntaxList,
@@ -413,9 +429,9 @@ namespace ts {
         LastBinaryOperator = CaretEqualsToken,
         FirstNode = QualifiedName,
         FirstJSDocNode = JSDocTypeExpression,
-        LastJSDocNode = JSDocTypeLiteral,
+        LastJSDocNode = JSDocPropertyTag,
         FirstJSDocTagNode = JSDocTag,
-        LastJSDocTagNode = JSDocTypeLiteral
+        LastJSDocTagNode = JSDocPropertyTag
     }
 
     export const enum NodeFlags {
@@ -451,7 +467,8 @@ namespace ts {
         /* @internal */
         PossiblyContainsDynamicImport = 1 << 19,
         JSDoc =              1 << 20, // If node was parsed inside jsdoc
-        /* @internal */ InWithStatement =    1 << 21, // If any ancestor of node was the `statement` of a WithStatement (not the `expression`)
+        /* @internal */ Ambient =         1 << 21, // If node was inside an ambient context -- a declaration file, or inside something with the `declare` modifier.
+        /* @internal */ InWithStatement = 1 << 22, // If any ancestor of node was the `statement` of a WithStatement (not the `expression`)
 
         BlockScoped = Let | Const,
 
@@ -459,7 +476,7 @@ namespace ts {
         ReachabilityAndEmitFlags = ReachabilityCheckFlags | HasAsyncFunctions,
 
         // Parsing context flags
-        ContextFlags = DisallowInContext | YieldContext | DecoratorContext | AwaitContext | JavaScriptFile | InWithStatement,
+        ContextFlags = DisallowInContext | YieldContext | DecoratorContext | AwaitContext | JavaScriptFile | InWithStatement | Ambient,
 
         // Exclude these flags when parsing a Type
         TypeExcludesFlags = YieldContext | AwaitContext,
@@ -516,7 +533,6 @@ namespace ts {
         /* @internal */ id?: number;                          // Unique id (used to look up NodeLinks)
         parent?: Node;                                        // Parent node (initialized by binding)
         /* @internal */ original?: Node;                      // The original node if this is an updated node.
-        /* @internal */ startsOnNewLine?: boolean;            // Whether a synthesized node should start on a new line (used by transforms).
         /* @internal */ symbol?: Symbol;                      // Symbol declared by node (initialized by binding)
         /* @internal */ locals?: SymbolTable;                 // Locals associated with node (initialized by binding)
         /* @internal */ nextContainer?: Node;                 // Next container in declaration order (initialized by binding)
@@ -626,6 +642,7 @@ namespace ts {
         isInJSDocNamespace?: boolean;                             // if the node is a member in a JSDoc namespace
         /*@internal*/ typeArguments?: NodeArray<TypeNode>;        // Only defined on synthesized nodes. Though not syntactically valid, used in emitting diagnostics.
         /*@internal*/ jsdocDotPos?: number;                       // Identifier occurs in JSDoc-style generic: Id.<T>
+        /*@internal*/ skipNameGenerationScope?: boolean;          // Should skip a name generation scope when generating the name for this identifier
     }
 
     // Transient identifier node (marked by id === -1)
@@ -1620,7 +1637,7 @@ namespace ts {
         closingElement: JsxClosingElement;
     }
 
-    /// Either the opening tag in a <Tag>...</Tag> pair, or the lone <Tag /> in a self-closing form
+    /// Either the opening tag in a <Tag>...</Tag> pair or the lone <Tag /> in a self-closing form
     export type JsxOpeningLikeElement = JsxSelfClosingElement | JsxOpeningElement;
 
     export type JsxAttributeLike = JsxAttribute | JsxSpreadAttribute;
@@ -1646,6 +1663,26 @@ namespace ts {
         attributes: JsxAttributes;
     }
 
+    /// A JSX expression of the form <>...</>
+    export interface JsxFragment extends PrimaryExpression {
+        kind: SyntaxKind.JsxFragment;
+        openingFragment: JsxOpeningFragment;
+        children: NodeArray<JsxChild>;
+        closingFragment: JsxClosingFragment;
+    }
+
+    /// The opening element of a <>...</> JsxFragment
+    export interface JsxOpeningFragment extends Expression {
+        kind: SyntaxKind.JsxOpeningFragment;
+        parent?: JsxFragment;
+    }
+
+    /// The closing element of a <>...</> JsxFragment
+    export interface JsxClosingFragment extends Expression {
+        kind: SyntaxKind.JsxClosingFragment;
+        parent?: JsxFragment;
+    }
+
     export interface JsxAttribute extends ObjectLiteralElement {
         kind: SyntaxKind.JsxAttribute;
         parent?: JsxAttributes;
@@ -1679,7 +1716,7 @@ namespace ts {
         parent?: JsxElement;
     }
 
-    export type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement;
+    export type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement | JsxFragment;
 
     export interface Statement extends Node {
         _statementBrand: any;
@@ -2429,8 +2466,8 @@ namespace ts {
 
     export interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
 
@@ -2448,9 +2485,13 @@ namespace ts {
         readFile(path: string): string | undefined;
     }
 
-    export interface WriteFileCallback {
-        (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>): void;
-    }
+    export type WriteFileCallback = (
+        fileName: string,
+        data: string,
+        writeByteOrderMark: boolean,
+        onError: ((message: string) => void) | undefined,
+        sourceFiles: ReadonlyArray<SourceFile>,
+    ) => void;
 
     export class OperationCanceledException { }
 
@@ -2980,6 +3021,10 @@ namespace ts {
         Optional                = 1 << 24,  // Optional property
         Transient               = 1 << 25,  // Transient symbol (created during type check)
 
+        /* @internal */
+        All = FunctionScopedVariable | BlockScopedVariable | Property | EnumMember | Function | Class | Interface | ConstEnum | RegularEnum | ValueModule | NamespaceModule | TypeLiteral
+            | ObjectLiteral | Method | Constructor | GetAccessor | SetAccessor | Signature | TypeParameter | TypeAlias | ExportValue | Alias | Prototype | ExportStar | Optional | Transient,
+
         Enum = RegularEnum | ConstEnum,
         Variable = FunctionScopedVariable | BlockScopedVariable,
         Value = Variable | Property | EnumMember | Function | Class | Enum | ValueModule | Method | GetAccessor | SetAccessor,
@@ -3327,6 +3372,7 @@ namespace ts {
         ObjectLiteral    = 1 << 7,  // Originates in an object literal
         EvolvingArray    = 1 << 8,  // Evolving array type
         ObjectLiteralPatternWithComputedProperties = 1 << 9,  // Object literal pattern with computed properties
+        ContainsSpread   = 1 << 10, // Object literal contains spread operation
         ClassOrInterface = Class | Interface
     }
 
@@ -3558,9 +3604,7 @@ namespace ts {
     }
 
     /* @internal */
-    export interface TypeMapper {
-        (t: TypeParameter): Type;
-    }
+    export type TypeMapper = (t: TypeParameter) => Type;
 
     export const enum InferencePriority {
         Contravariant     = 1 << 0,  // Inference from contravariant position
@@ -3609,6 +3653,14 @@ namespace ts {
         compareTypes: TypeComparer;         // Type comparer function
     }
 
+    /* @internal */
+    export interface WideningContext {
+        parent?: WideningContext;            // Parent context
+        propertyName?: __String;             // Name of property in parent
+        siblings?: Type[];                   // Types of siblings
+        resolvedPropertyNames?: __String[];  // Property names occurring in sibling object literals
+    }
+
     /* @internal */
     export const enum SpecialPropertyAssignmentKind {
         None,
@@ -4160,9 +4212,7 @@ namespace ts {
     }
 
     /* @internal */
-    export interface HasInvalidatedResolution {
-        (sourceFile: Path): boolean;
-    }
+    export type HasInvalidatedResolution = (sourceFile: Path) => boolean;
 
     export interface CompilerHost extends ModuleResolutionHost {
         getSourceFile(fileName: string, languageVersion: ScriptTarget, onError?: (message: string) => void, shouldCreateNewSourceFile?: boolean): SourceFile | undefined;
@@ -4297,6 +4347,7 @@ namespace ts {
         constantValue?: string | number;         // The constant value of an expression
         externalHelpersModuleName?: Identifier;  // The local name for an imported helpers module
         helpers?: EmitHelper[];                  // Emit helpers for the node
+        startsOnNewLine?: boolean;               // If the node should begin on a new line
     }
 
     export const enum EmitFlags {
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 01bb36e9065..41a5512cb2a 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -321,16 +321,16 @@ namespace ts {
         return getSourceTextOfNodeFromSourceFile(getSourceFileOfNode(node), node, includeTrivia);
     }
 
+    function getPos(range: Node) {
+        return range.pos;
+    }
+
     /**
      * Note: it is expected that the `nodeArray` and the `node` are within the same file.
      * For example, searching for a `SourceFile` in a `SourceFile[]` wouldn't work.
      */
     export function indexOfNode(nodeArray: ReadonlyArray<Node>, node: Node) {
-        return binarySearch(nodeArray, node, compareNodePos);
-    }
-
-    function compareNodePos({ pos: aPos }: Node, { pos: bPos}: Node) {
-        return aPos < bPos ? Comparison.LessThan : bPos < aPos ? Comparison.GreaterThan : Comparison.EqualTo;
+        return binarySearch(nodeArray, node, getPos, compareValues);
     }
 
     /**
@@ -363,8 +363,10 @@ namespace ts {
             case SyntaxKind.NoSubstitutionTemplateLiteral:
                 return "`" + escapeText(node.text, CharacterCodes.backtick) + "`";
             case SyntaxKind.TemplateHead:
+                // tslint:disable-next-line no-invalid-template-strings
                 return "`" + escapeText(node.text, CharacterCodes.backtick) + "${";
             case SyntaxKind.TemplateMiddle:
+                // tslint:disable-next-line no-invalid-template-strings
                 return "}" + escapeText(node.text, CharacterCodes.backtick) + "${";
             case SyntaxKind.TemplateTail:
                 return "}" + escapeText(node.text, CharacterCodes.backtick) + "`";
@@ -1132,7 +1134,7 @@ namespace ts {
     }
 
     /**
-     * Determines whether a node is a property or element access expression for super.
+     * Determines whether a node is a property or element access expression for `super`.
      */
     export function isSuperProperty(node: Node): node is SuperProperty {
         const kind = node.kind;
@@ -1140,7 +1142,16 @@ namespace ts {
             && (<PropertyAccessExpression | ElementAccessExpression>node).expression.kind === SyntaxKind.SuperKeyword;
     }
 
-    export function getEntityNameFromTypeNode(node: TypeNode): EntityNameOrEntityNameExpression {
+    /**
+     * Determines whether a node is a property or element access expression for `this`.
+     */
+    export function isThisProperty(node: Node): boolean {
+        const kind = node.kind;
+        return (kind === SyntaxKind.PropertyAccessExpression || kind === SyntaxKind.ElementAccessExpression)
+            && (<PropertyAccessExpression | ElementAccessExpression>node).expression.kind === SyntaxKind.ThisKeyword;
+    }
+
+   export function getEntityNameFromTypeNode(node: TypeNode): EntityNameOrEntityNameExpression {
         switch (node.kind) {
             case SyntaxKind.TypeReference:
                 return (<TypeReferenceNode>node).typeName;
@@ -1228,7 +1239,7 @@ namespace ts {
         return false;
     }
 
-    export function isPartOfExpression(node: Node): boolean {
+    export function isExpressionNode(node: Node): boolean {
         switch (node.kind) {
             case SyntaxKind.SuperKeyword:
             case SyntaxKind.NullKeyword:
@@ -1262,6 +1273,7 @@ namespace ts {
             case SyntaxKind.OmittedExpression:
             case SyntaxKind.JsxElement:
             case SyntaxKind.JsxSelfClosingElement:
+            case SyntaxKind.JsxFragment:
             case SyntaxKind.YieldExpression:
             case SyntaxKind.AwaitExpression:
             case SyntaxKind.MetaProperty:
@@ -1331,7 +1343,7 @@ namespace ts {
             case SyntaxKind.ExpressionWithTypeArguments:
                 return (<ExpressionWithTypeArguments>parent).expression === node && isExpressionWithTypeArgumentsInClassExtendsClause(parent);
             default:
-                return isPartOfExpression(parent);
+                return isExpressionNode(parent);
         }
     }
 
@@ -1394,8 +1406,8 @@ namespace ts {
         return charCode === CharacterCodes.singleQuote || charCode === CharacterCodes.doubleQuote;
     }
 
-    export function isStringDoubleQuoted(string: StringLiteral, sourceFile: SourceFile): boolean {
-        return getSourceTextOfNodeFromSourceFile(sourceFile, string).charCodeAt(0) === CharacterCodes.doubleQuote;
+    export function isStringDoubleQuoted(str: StringLiteral, sourceFile: SourceFile): boolean {
+        return getSourceTextOfNodeFromSourceFile(sourceFile, str).charCodeAt(0) === CharacterCodes.doubleQuote;
     }
 
     /**
@@ -1718,16 +1730,6 @@ namespace ts {
         return false;
     }
 
-    export function isInAmbientContext(node: Node): boolean {
-        while (node) {
-            if (hasModifier(node, ModifierFlags.Ambient) || (node.kind === SyntaxKind.SourceFile && (node as SourceFile).isDeclarationFile)) {
-                return true;
-            }
-            node = node.parent;
-        }
-        return false;
-    }
-
     // True if the given identifier, string literal, or number literal is the name of a declaration node
     export function isDeclarationName(name: Node): boolean {
         switch (name.kind) {
@@ -2170,6 +2172,7 @@ namespace ts {
             case SyntaxKind.ClassExpression:
             case SyntaxKind.JsxElement:
             case SyntaxKind.JsxSelfClosingElement:
+            case SyntaxKind.JsxFragment:
             case SyntaxKind.RegularExpressionLiteral:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateExpression:
@@ -2291,6 +2294,7 @@ namespace ts {
         let nonFileDiagnostics: Diagnostic[] = [];
         const fileDiagnostics = createMap<Diagnostic[]>();
 
+        let hasReadNonFileDiagnostics = false;
         let diagnosticsModified = false;
         let modificationCount = 0;
 
@@ -2320,6 +2324,12 @@ namespace ts {
                 }
             }
             else {
+                // If we've already read the non-file diagnostics, do not modify the existing array.
+                if (hasReadNonFileDiagnostics) {
+                    hasReadNonFileDiagnostics = false;
+                    nonFileDiagnostics = nonFileDiagnostics.slice();
+                }
+
                 diagnostics = nonFileDiagnostics;
             }
 
@@ -2330,6 +2340,7 @@ namespace ts {
 
         function getGlobalDiagnostics(): Diagnostic[] {
             sortAndDeduplicate();
+            hasReadNonFileDiagnostics = true;
             return nonFileDiagnostics;
         }
 
@@ -3591,7 +3602,7 @@ namespace ts {
     }
 
     /** Calls `callback` on `directory` and every ancestor directory it has, returning the first defined result. */
-    export function forEachAncestorDirectory<T>(directory: string, callback: (directory: string) => T): T {
+    export function forEachAncestorDirectory<T>(directory: string, callback: (directory: string) => T | undefined): T | undefined {
         while (true) {
             const result = callback(directory);
             if (result !== undefined) {
@@ -3949,6 +3960,9 @@ namespace ts {
             trySetLanguageAndTerritory(language, /*territory*/ undefined, errors);
         }
 
+        // Set the UI locale for string collation
+        setUILocale(locale);
+
         function trySetLanguageAndTerritory(language: string, territory: string, errors?: Push<Diagnostic>): boolean {
             const compilerFilePath = normalizePath(sys.getExecutingFilePath());
             const containingDirectoryPath = getDirectoryPath(compilerFilePath);
@@ -4794,6 +4808,18 @@ namespace ts {
         return node.kind === SyntaxKind.JsxClosingElement;
     }
 
+    export function isJsxFragment(node: Node): node is JsxFragment {
+        return node.kind === SyntaxKind.JsxFragment;
+    }
+
+    export function isJsxOpeningFragment(node: Node): node is JsxOpeningFragment {
+        return node.kind === SyntaxKind.JsxOpeningFragment;
+    }
+
+    export function isJsxClosingFragment(node: Node): node is JsxClosingFragment {
+        return node.kind === SyntaxKind.JsxClosingFragment;
+    }
+
     export function isJsxAttribute(node: Node): node is JsxAttribute {
         return node.kind === SyntaxKind.JsxAttribute;
     }
@@ -5319,6 +5345,7 @@ namespace ts {
             case SyntaxKind.CallExpression:
             case SyntaxKind.JsxElement:
             case SyntaxKind.JsxSelfClosingElement:
+            case SyntaxKind.JsxFragment:
             case SyntaxKind.TaggedTemplateExpression:
             case SyntaxKind.ArrayLiteralExpression:
             case SyntaxKind.ParenthesizedExpression:
@@ -5381,7 +5408,7 @@ namespace ts {
     /* @internal */
     /**
      * Determines whether a node is an expression based only on its kind.
-     * Use `isPartOfExpression` if not in transforms.
+     * Use `isExpressionNode` if not in transforms.
      */
     export function isExpression(node: Node): node is Expression {
         return isExpressionKind(skipPartiallyEmittedExpressions(node).kind);
@@ -5640,7 +5667,8 @@ namespace ts {
         return kind === SyntaxKind.JsxElement
             || kind === SyntaxKind.JsxExpression
             || kind === SyntaxKind.JsxSelfClosingElement
-            || kind === SyntaxKind.JsxText;
+            || kind === SyntaxKind.JsxText
+            || kind === SyntaxKind.JsxFragment;
     }
 
     /* @internal */
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 7d46630e227..0b40e20a7b7 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -819,6 +819,12 @@ namespace ts {
                 return updateJsxClosingElement(<JsxClosingElement>node,
                     visitNode((<JsxClosingElement>node).tagName, visitor, isJsxTagNameExpression));
 
+            case SyntaxKind.JsxFragment:
+                return updateJsxFragment(<JsxFragment>node,
+                    visitNode((<JsxFragment>node).openingFragment, visitor, isJsxOpeningFragment),
+                    nodesVisitor((<JsxFragment>node).children, visitor, isJsxChild),
+                    visitNode((<JsxFragment>node).closingFragment, visitor, isJsxClosingFragment));
+
             case SyntaxKind.JsxAttribute:
                 return updateJsxAttribute(<JsxAttribute>node,
                     visitNode((<JsxAttribute>node).name, visitor, isIdentifier),
@@ -1334,6 +1340,12 @@ namespace ts {
                 result = reduceNode((<JsxElement>node).closingElement, cbNode, result);
                 break;
 
+            case SyntaxKind.JsxFragment:
+                result = reduceNode((<JsxFragment>node).openingFragment, cbNode, result);
+                result = reduceLeft((<JsxFragment>node).children, cbNode, result);
+                result = reduceNode((<JsxFragment>node).closingFragment, cbNode, result);
+                break;
+
             case SyntaxKind.JsxSelfClosingElement:
             case SyntaxKind.JsxOpeningElement:
                 result = reduceNode((<JsxSelfClosingElement | JsxOpeningElement>node).tagName, cbNode, result);
@@ -1573,13 +1585,13 @@ namespace ts {
 
             // Add additional properties in debug mode to assist with debugging.
             Object.defineProperties(objectAllocator.getSymbolConstructor().prototype, {
-                "__debugFlags": { get(this: Symbol) { return formatSymbolFlags(this.flags); } }
+                __debugFlags: { get(this: Symbol) { return formatSymbolFlags(this.flags); } }
             });
 
             Object.defineProperties(objectAllocator.getTypeConstructor().prototype, {
-                "__debugFlags": { get(this: Type) { return formatTypeFlags(this.flags); } },
-                "__debugObjectFlags": { get(this: Type) { return this.flags & TypeFlags.Object ? formatObjectFlags((<ObjectType>this).objectFlags) : ""; } },
-                "__debugTypeToString": { value(this: Type) { return this.checker.typeToString(this); } },
+                __debugFlags: { get(this: Type) { return formatTypeFlags(this.flags); } },
+                __debugObjectFlags: { get(this: Type) { return this.flags & TypeFlags.Object ? formatObjectFlags((<ObjectType>this).objectFlags) : ""; } },
+                __debugTypeToString: { value(this: Type) { return this.checker.typeToString(this); } },
             });
 
             const nodeConstructors = [
@@ -1592,11 +1604,11 @@ namespace ts {
             for (const ctor of nodeConstructors) {
                 if (!ctor.prototype.hasOwnProperty("__debugKind")) {
                     Object.defineProperties(ctor.prototype, {
-                        "__debugKind": { get(this: Node) { return formatSyntaxKind(this.kind); } },
-                        "__debugModifierFlags": { get(this: Node) { return formatModifierFlags(getModifierFlagsNoCache(this)); } },
-                        "__debugTransformFlags": { get(this: Node) { return formatTransformFlags(this.transformFlags); } },
-                        "__debugEmitFlags": { get(this: Node) { return formatEmitFlags(getEmitFlags(this)); } },
-                        "__debugGetText": {
+                        __debugKind: { get(this: Node) { return formatSyntaxKind(this.kind); } },
+                        __debugModifierFlags: { get(this: Node) { return formatModifierFlags(getModifierFlagsNoCache(this)); } },
+                        __debugTransformFlags: { get(this: Node) { return formatTransformFlags(this.transformFlags); } },
+                        __debugEmitFlags: { get(this: Node) { return formatEmitFlags(getEmitFlags(this)); } },
+                        __debugGetText: {
                             value(this: Node, includeTrivia?: boolean) {
                                 if (nodeIsSynthesized(this)) return "";
                                 const parseNode = getParseTreeNode(this);
diff --git a/src/compiler/watch.ts b/src/compiler/watch.ts
index 53692fe1e04..8e49bb71a15 100644
--- a/src/compiler/watch.ts
+++ b/src/compiler/watch.ts
@@ -230,7 +230,7 @@ namespace ts {
 
     function createWatchMode(rootFileNames: string[], compilerOptions: CompilerOptions, watchingHost?: WatchingSystemHost, configFileName?: string, configFileSpecs?: ConfigFileSpecs, configFileWildCardDirectories?: MapLike<WatchDirectoryFlags>, optionsToExtendForConfigFile?: CompilerOptions) {
         let program: Program;
-        let needsReload: boolean;                                           // true if the config file changed and needs to reload it from the disk
+        let reloadLevel: ConfigFileProgramReloadLevel;                      // level to indicate if the program needs to be reloaded from config file/just filenames etc
         let missingFilesMap: Map<FileWatcher>;                              // Map of file watchers for the missing files
         let watchedWildcardDirectories: Map<WildcardDirectoryWatcher>;      // map of watchers for the wild card directories in the config file
         let timerToUpdateProgram: any;                                      // timer callback to recompile the program
@@ -488,7 +488,7 @@ namespace ts {
 
         function scheduleProgramReload() {
             Debug.assert(!!configFileName);
-            needsReload = true;
+            reloadLevel = ConfigFileProgramReloadLevel.Full;
             scheduleProgramUpdate();
         }
 
@@ -496,17 +496,30 @@ namespace ts {
             timerToUpdateProgram = undefined;
             reportWatchDiagnostic(createCompilerDiagnostic(Diagnostics.File_change_detected_Starting_incremental_compilation));
 
-            if (needsReload) {
-                reloadConfigFile();
+            switch (reloadLevel) {
+                case ConfigFileProgramReloadLevel.Partial:
+                    return reloadFileNamesFromConfigFile();
+                case ConfigFileProgramReloadLevel.Full:
+                    return reloadConfigFile();
+                default:
+                    return synchronizeProgram();
             }
-            else {
-                synchronizeProgram();
+        }
+
+        function reloadFileNamesFromConfigFile() {
+            const result = getFileNamesFromConfigSpecs(configFileSpecs, getDirectoryPath(configFileName), compilerOptions, directoryStructureHost);
+            if (!configFileSpecs.filesSpecs && result.fileNames.length === 0) {
+                reportDiagnostic(getErrorForNoInputFiles(configFileSpecs, configFileName));
             }
+            rootFileNames = result.fileNames;
+
+            // Update the program
+            synchronizeProgram();
         }
 
         function reloadConfigFile() {
             writeLog(`Reloading config file: ${configFileName}`);
-            needsReload = false;
+            reloadLevel = ConfigFileProgramReloadLevel.None;
 
             const cachedHost = directoryStructureHost as CachedDirectoryStructureHost;
             cachedHost.clearCache();
@@ -611,18 +624,14 @@ namespace ts {
 
                     // If the the added or created file or directory is not supported file name, ignore the file
                     // But when watched directory is added/removed, we need to reload the file list
-                    if (fileOrDirectoryPath !== directory && !isSupportedSourceFileName(fileOrDirectory, compilerOptions)) {
+                    if (fileOrDirectoryPath !== directory && hasExtension(fileOrDirectoryPath) && !isSupportedSourceFileName(fileOrDirectory, compilerOptions)) {
                         writeLog(`Project: ${configFileName} Detected file add/remove of non supported extension: ${fileOrDirectory}`);
                         return;
                     }
 
                     // Reload is pending, do the reload
-                    if (!needsReload) {
-                        const result = getFileNamesFromConfigSpecs(configFileSpecs, getDirectoryPath(configFileName), compilerOptions, directoryStructureHost);
-                        if (!configFileSpecs.filesSpecs && result.fileNames.length === 0) {
-                            reportDiagnostic(getErrorForNoInputFiles(configFileSpecs, configFileName));
-                        }
-                        rootFileNames = result.fileNames;
+                    if (reloadLevel !== ConfigFileProgramReloadLevel.Full) {
+                        reloadLevel = ConfigFileProgramReloadLevel.Partial;
 
                         // Schedule Update the program
                         scheduleProgramUpdate();
diff --git a/src/compiler/watchUtilities.ts b/src/compiler/watchUtilities.ts
index f39024d5a7c..0cf38f372d9 100644
--- a/src/compiler/watchUtilities.ts
+++ b/src/compiler/watchUtilities.ts
@@ -2,6 +2,14 @@
 
 /* @internal */
 namespace ts {
+    export enum ConfigFileProgramReloadLevel {
+        None,
+        /** Update the file name list from the disk */
+        Partial,
+        /** Reload completely by re-reading contents of config file from disk and updating program */
+        Full
+    }
+
     /**
      * Updates the existing missing file watches with the new set of missing files after new program is created
      */
diff --git a/src/harness/compilerRunner.ts b/src/harness/compilerRunner.ts
index c58accb657c..30c5e47949f 100644
--- a/src/harness/compilerRunner.ts
+++ b/src/harness/compilerRunner.ts
@@ -211,8 +211,8 @@ class CompilerBaselineRunner extends RunnerBase {
             this.emit = false;
 
             const opts = this.options.split(",");
-            for (let i = 0; i < opts.length; i++) {
-                switch (opts[i]) {
+            for (const opt of opts) {
+                switch (opt) {
                     case "emit":
                         this.emit = true;
                         break;
diff --git a/src/harness/externalCompileRunner.ts b/src/harness/externalCompileRunner.ts
new file mode 100644
index 00000000000..9b8fc8c4fc5
--- /dev/null
+++ b/src/harness/externalCompileRunner.ts
@@ -0,0 +1,67 @@
+/// <reference path="harness.ts"/>
+/// <reference path="runnerbase.ts" />
+abstract class ExternalCompileRunnerBase extends RunnerBase {
+    abstract testDir: string;
+    public enumerateTestFiles() {
+        return Harness.IO.getDirectories(this.testDir);
+    }
+    /** Setup the runner's tests so that they are ready to be executed by the harness
+     *  The first test should be a describe/it block that sets up the harness's compiler instance appropriately
+     */
+    public initializeTests(): void {
+        // Read in and evaluate the test list
+        const testList = this.tests && this.tests.length ? this.tests : this.enumerateTestFiles();
+
+        describe(`${this.kind()} code samples`, () => {
+            for (const test of testList) {
+                this.runTest(test);
+            }
+        });
+    }
+    private runTest(directoryName: string) {
+        describe(directoryName, () => {
+            const cp = require("child_process");
+            const path = require("path");
+            const fs = require("fs");
+
+            it("should build successfully", () => {
+                const cwd = path.join(__dirname, "../../", this.testDir, directoryName);
+                const timeout = 600000; // 600s = 10 minutes
+                if (fs.existsSync(path.join(cwd, "package.json"))) {
+                    if (fs.existsSync(path.join(cwd, "package-lock.json"))) {
+                        fs.unlinkSync(path.join(cwd, "package-lock.json"));
+                    }
+                    const stdio = isWorker ? "pipe" : "inherit";
+                    const install = cp.spawnSync(`npm`, ["i"], { cwd, timeout, shell: true, stdio });
+                    if (install.status !== 0) throw new Error(`NPM Install for ${directoryName} failed!`);
+                }
+                Harness.Baseline.runBaseline(`${this.kind()}/${directoryName}.log`, () => {
+                    const result = cp.spawnSync(`node`, [path.join(__dirname, "tsc.js")], { cwd, timeout, shell: true });
+                    // tslint:disable-next-line:no-null-keyword
+                    return result.status === 0 && !result.stdout.length && !result.stderr.length ? null : `Exit Code: ${result.status}
+Standard output:
+${result.stdout.toString().replace(/\r\n/g, "\n")}
+
+
+Standard error:
+${result.stderr.toString().replace(/\r\n/g, "\n")}`;
+                });
+            });
+        });
+    }
+}
+
+class UserCodeRunner extends ExternalCompileRunnerBase {
+    public readonly testDir = "tests/cases/user/";
+    public kind(): TestRunnerKind {
+        return "user";
+    }
+}
+
+class DefinitelyTypedRunner extends ExternalCompileRunnerBase {
+    public readonly testDir = "../DefinitelyTyped/types/";
+    public workingDirectory = this.testDir;
+    public kind(): TestRunnerKind {
+        return "dt";
+    }
+}
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 7ba4e94902d..c9aa1c6403d 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -126,8 +126,8 @@ namespace FourSlash {
         // 0 - cancelled
         // >0 - not cancelled
         // <0 - not cancelled and value denotes number of isCancellationRequested after which token become cancelled
-        private static readonly NotCanceled: number = -1;
-        private numberOfCallsBeforeCancellation: number = TestCancellationToken.NotCanceled;
+        private static readonly notCanceled = -1;
+        private numberOfCallsBeforeCancellation = TestCancellationToken.notCanceled;
 
         public isCancellationRequested(): boolean {
             if (this.numberOfCallsBeforeCancellation < 0) {
@@ -148,7 +148,7 @@ namespace FourSlash {
         }
 
         public resetCancelled(): void {
-            this.numberOfCallsBeforeCancellation = TestCancellationToken.NotCanceled;
+            this.numberOfCallsBeforeCancellation = TestCancellationToken.notCanceled;
         }
     }
 
@@ -221,11 +221,9 @@ namespace FourSlash {
         private addMatchedInputFile(referenceFilePath: string, extensions: ReadonlyArray<string>) {
             const inputFiles = this.inputFiles;
             const languageServiceAdapterHost = this.languageServiceAdapterHost;
-            if (!extensions) {
-                tryAdd(referenceFilePath);
-            }
-            else {
-                tryAdd(referenceFilePath) || ts.forEach(extensions, ext => tryAdd(referenceFilePath + ext));
+            const didAdd = tryAdd(referenceFilePath);
+            if (extensions && !didAdd) {
+                ts.forEach(extensions, ext => tryAdd(referenceFilePath + ext));
             }
 
             function tryAdd(path: string) {
@@ -314,7 +312,7 @@ namespace FourSlash {
 
             const languageServiceAdapter = this.getLanguageServiceAdapter(testType, this.cancellationToken, compilationOptions);
             this.languageServiceAdapterHost = languageServiceAdapter.getHost();
-            this.languageService = languageServiceAdapter.getLanguageService();
+            this.languageService = memoWrap(languageServiceAdapter.getLanguageService(), this); // Wrap the LS to cache some expensive operations certain tests call repeatedly
 
             if (startResolveFileRef) {
                 // Add the entry-point file itself into the languageServiceShimHost
@@ -381,6 +379,39 @@ namespace FourSlash {
 
             // Open the first file by default
             this.openFile(0);
+
+            function memoWrap(ls: ts.LanguageService, target: TestState): ts.LanguageService {
+                const cacheableMembers: (keyof typeof ls)[] = [
+                    "getCompletionsAtPosition",
+                    "getCompletionEntryDetails",
+                    "getCompletionEntrySymbol",
+                    "getQuickInfoAtPosition",
+                    "getSignatureHelpItems",
+                    "getReferencesAtPosition",
+                    "getDocumentHighlights",
+                ];
+                const proxy = {} as ts.LanguageService;
+                for (const k in ls) {
+                    const key = k as keyof typeof ls;
+                    if (cacheableMembers.indexOf(key) === -1) {
+                        proxy[key] = (...args: any[]) => (ls[key] as Function)(...args);
+                        continue;
+                    }
+                    const memo = Utils.memoize(
+                        (_version: number, _active: string, _caret: number, _selectEnd: number, _marker: string, ...args: any[]) => (ls[key] as Function)(...args),
+                        (...args) => args.join("|,|")
+                    );
+                    proxy[key] = (...args: any[]) => memo(
+                        target.languageServiceAdapterHost.getScriptInfo(target.activeFile.fileName).version,
+                        target.activeFile.fileName,
+                        target.currentCaretPosition,
+                        target.selectionEnd,
+                        target.lastKnownMarker,
+                        ...args
+                    );
+                }
+                return proxy;
+            }
         }
 
         private getFileContent(fileName: string): string {
@@ -437,6 +468,10 @@ namespace FourSlash {
 
         public select(startMarker: string, endMarker: string) {
             const start = this.getMarkerByName(startMarker), end = this.getMarkerByName(endMarker);
+            ts.Debug.assert(start.fileName === end.fileName);
+            if (this.activeFile.fileName !== start.fileName) {
+                this.openFile(start.fileName);
+            }
             this.goToPosition(start.position);
             this.selectionEnd = end.position;
         }
@@ -448,9 +483,7 @@ namespace FourSlash {
         }
 
         // Opens a file given its 0-based index or fileName
-        public openFile(index: number, content?: string, scriptKindName?: string): void;
-        public openFile(name: string, content?: string, scriptKindName?: string): void;
-        public openFile(indexOrName: any, content?: string, scriptKindName?: string) {
+        public openFile(indexOrName: number | string, content?: string, scriptKindName?: string): void {
             const fileToOpen: FourSlashFile = this.findFile(indexOrName);
             fileToOpen.fileName = ts.normalizeSlashes(fileToOpen.fileName);
             this.activeFile = fileToOpen;
@@ -531,15 +564,31 @@ namespace FourSlash {
             }
 
             for (const { start, length, messageText, file } of errors) {
-                Harness.IO.log("  from: " + showPosition(file, start) +
-                    ", to: " + showPosition(file, start + length) +
+                Harness.IO.log("  " + this.formatRange(file, start, length) +
                     ", message: " + ts.flattenDiagnosticMessageText(messageText, Harness.IO.newLine()) + "\n");
             }
+        }
 
-            function showPosition(file: ts.SourceFile, pos: number) {
+        private formatRange(file: ts.SourceFile, start: number, length: number) {
+            if (file) {
+                return `from: ${this.formatLineAndCharacterOfPosition(file, start)}, to: ${this.formatLineAndCharacterOfPosition(file, start + length)}`;
+            }
+            return "global";
+        }
+
+        private formatLineAndCharacterOfPosition(file: ts.SourceFile, pos: number) {
+            if (file) {
                 const { line, character } = ts.getLineAndCharacterOfPosition(file, pos);
                 return `${line}:${character}`;
             }
+            return "global";
+        }
+
+        private formatPosition(file: ts.SourceFile, pos: number) {
+            if (file) {
+                return file.fileName + "@" + pos;
+            }
+            return "global";
         }
 
         public verifyNoErrors() {
@@ -549,7 +598,7 @@ namespace FourSlash {
                 if (errors.length) {
                     this.printErrorLog(/*expectErrors*/ false, errors);
                     const error = errors[0];
-                    this.raiseError(`Found an error: ${error.file.fileName}@${error.start}: ${error.messageText}`);
+                    this.raiseError(`Found an error: ${this.formatPosition(error.file, error.start)}: ${error.messageText}`);
                 }
             });
         }
@@ -583,19 +632,23 @@ namespace FourSlash {
         }
 
         public verifyGoToDefinition(arg0: any, endMarkerNames?: string | string[]) {
-            this.verifyGoToX(arg0, endMarkerNames, () => this.getGoToDefinition());
+            this.verifyGoToX(arg0, endMarkerNames, () => this.getGoToDefinitionAndBoundSpan());
         }
 
         private getGoToDefinition(): ts.DefinitionInfo[] {
             return this.languageService.getDefinitionAtPosition(this.activeFile.fileName, this.currentCaretPosition);
         }
 
+        private getGoToDefinitionAndBoundSpan(): ts.DefinitionInfoAndBoundSpan {
+            return this.languageService.getDefinitionAndBoundSpan(this.activeFile.fileName, this.currentCaretPosition);
+        }
+
         public verifyGoToType(arg0: any, endMarkerNames?: string | string[]) {
             this.verifyGoToX(arg0, endMarkerNames, () =>
                 this.languageService.getTypeDefinitionAtPosition(this.activeFile.fileName, this.currentCaretPosition));
         }
 
-        private verifyGoToX(arg0: any, endMarkerNames: string | string[] | undefined, getDefs: () => ts.DefinitionInfo[] | undefined) {
+        private verifyGoToX(arg0: any, endMarkerNames: string | string[] | undefined, getDefs: () => ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             if (endMarkerNames) {
                 this.verifyGoToXPlain(arg0, endMarkerNames, getDefs);
             }
@@ -615,7 +668,7 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXPlain(startMarkerNames: string | string[], endMarkerNames: string | string[], getDefs: () => ts.DefinitionInfo[] | undefined) {
+        private verifyGoToXPlain(startMarkerNames: string | string[], endMarkerNames: string | string[], getDefs: () => ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             for (const start of toArray(startMarkerNames)) {
                 this.verifyGoToXSingle(start, endMarkerNames, getDefs);
             }
@@ -627,26 +680,57 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: string | string[], getDefs: () => ts.DefinitionInfo[] | undefined) {
+        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: string | string[], getDefs: () => ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             this.goToMarker(startMarkerName);
-            this.verifyGoToXWorker(toArray(endMarkerNames), getDefs);
+            this.verifyGoToXWorker(toArray(endMarkerNames), getDefs, startMarkerName);
         }
 
-        private verifyGoToXWorker(endMarkers: string[], getDefs: () => ts.DefinitionInfo[] | undefined) {
-            const definitions = getDefs() || [];
+        private verifyGoToXWorker(endMarkers: string[], getDefs: () => ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined, startMarkerName?: string) {
+            const defs = getDefs();
+            let definitions: ts.DefinitionInfo[] | ReadonlyArray<ts.DefinitionInfo>;
+            let testName: string;
+
+            if (!defs || Array.isArray(defs)) {
+                definitions = defs as ts.DefinitionInfo[] || [];
+                testName = "goToDefinitions";
+            }
+            else {
+                this.verifyDefinitionTextSpan(defs, startMarkerName);
+
+                definitions = defs.definitions;
+                testName = "goToDefinitionsAndBoundSpan";
+            }
 
             if (endMarkers.length !== definitions.length) {
-                this.raiseError(`goToDefinitions failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
+                this.raiseError(`${testName} failed - expected to find ${endMarkers.length} definitions but got ${definitions.length}`);
             }
 
             ts.zipWith(endMarkers, definitions, (endMarker, definition, i) => {
                 const marker = this.getMarkerByName(endMarker);
                 if (marker.fileName !== definition.fileName || marker.position !== definition.textSpan.start) {
-                    this.raiseError(`goToDefinition failed for definition ${endMarker} (${i}): expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}`);
+                    this.raiseError(`${testName} failed for definition ${endMarker} (${i}): expected ${marker.fileName} at ${marker.position}, got ${definition.fileName} at ${definition.textSpan.start}`);
                 }
             });
         }
 
+        private verifyDefinitionTextSpan(defs: ts.DefinitionInfoAndBoundSpan, startMarkerName: string) {
+            const range = this.testData.ranges.find(range => this.markerName(range.marker) === startMarkerName);
+
+            if (!range && !defs.textSpan) {
+                return;
+            }
+
+            if (!range) {
+                this.raiseError(`goToDefinitionsAndBoundSpan failed - found a TextSpan ${JSON.stringify(defs.textSpan)} when it wasn't expected.`);
+            }
+            else if (defs.textSpan.start !== range.start || defs.textSpan.length !== range.end - range.start) {
+                const expected: ts.TextSpan = {
+                    start: range.start, length: range.end - range.start
+                };
+                this.raiseError(`goToDefinitionsAndBoundSpan failed - expected to find TextSpan ${JSON.stringify(expected)} but got ${JSON.stringify(defs.textSpan)}`);
+            }
+        }
+
         public verifyGetEmitOutputForCurrentFile(expected: string): void {
             const emit = this.languageService.getEmitOutput(this.activeFile.fileName);
             if (emit.outputFiles.length !== 1) {
@@ -783,8 +867,8 @@ namespace FourSlash {
             });
         }
 
-        public verifyCompletionListContains(entryId: ts.Completions.CompletionEntryIdentifier, text?: string, documentation?: string, kind?: string, spanIndex?: number, hasAction?: boolean) {
-            const completions = this.getCompletionListAtCaret();
+        public verifyCompletionListContains(entryId: ts.Completions.CompletionEntryIdentifier, text?: string, documentation?: string, kind?: string, spanIndex?: number, hasAction?: boolean, options?: ts.GetCompletionsAtPositionOptions) {
+            const completions = this.getCompletionListAtCaret(options);
             if (completions) {
                 this.assertItemInCompletionList(completions.entries, entryId, text, documentation, kind, spanIndex, hasAction);
             }
@@ -804,38 +888,35 @@ namespace FourSlash {
          * @param expectedKind the kind of symbol (see ScriptElementKind)
          * @param spanIndex the index of the range that the completion item's replacement text span should match
          */
-        public verifyCompletionListDoesNotContain(entryId: ts.Completions.CompletionEntryIdentifier, expectedText?: string, expectedDocumentation?: string, expectedKind?: string, spanIndex?: number) {
-            const that = this;
+        public verifyCompletionListDoesNotContain(entryId: ts.Completions.CompletionEntryIdentifier, expectedText?: string, expectedDocumentation?: string, expectedKind?: string, spanIndex?: number, options?: ts.GetCompletionsAtPositionOptions) {
             let replacementSpan: ts.TextSpan;
             if (spanIndex !== undefined) {
                 replacementSpan = this.getTextSpanForRangeAtIndex(spanIndex);
             }
 
-            function filterByTextOrDocumentation(entry: ts.CompletionEntry) {
-                const details = that.getCompletionEntryDetails(entry.name);
-                const documentation = details && ts.displayPartsToString(details.documentation);
-                const text = details && ts.displayPartsToString(details.displayParts);
-
-                // If any of the expected values are undefined, assume that users don't
-                // care about them.
-                if (replacementSpan && !TestState.textSpansEqual(replacementSpan, entry.replacementSpan)) {
-                    return false;
-                }
-                else if (expectedText && text !== expectedText) {
-                    return false;
-                }
-                else if (expectedDocumentation && documentation !== expectedDocumentation) {
-                    return false;
-                }
-
-                return true;
-            }
-
-            const completions = this.getCompletionListAtCaret();
+            const completions = this.getCompletionListAtCaret(options);
             if (completions) {
                 let filterCompletions = completions.entries.filter(e => e.name === entryId.name && e.source === entryId.source);
                 filterCompletions = expectedKind ? filterCompletions.filter(e => e.kind === expectedKind) : filterCompletions;
-                filterCompletions = filterCompletions.filter(filterByTextOrDocumentation);
+                filterCompletions = filterCompletions.filter(entry => {
+                    const details = this.getCompletionEntryDetails(entry.name);
+                    const documentation = details && ts.displayPartsToString(details.documentation);
+                    const text = details && ts.displayPartsToString(details.displayParts);
+
+                    // If any of the expected values are undefined, assume that users don't
+                    // care about them.
+                    if (replacementSpan && !TestState.textSpansEqual(replacementSpan, entry.replacementSpan)) {
+                        return false;
+                    }
+                    else if (expectedText && text !== expectedText) {
+                        return false;
+                    }
+                    else if (expectedDocumentation && documentation !== expectedDocumentation) {
+                        return false;
+                    }
+
+                    return true;
+                });
                 if (filterCompletions.length !== 0) {
                     // After filtered using all present criterion, if there are still symbol left in the list
                     // then these symbols must meet the criterion for Not supposed to be in the list. So we
@@ -1126,11 +1207,11 @@ Actual: ${stringify(fullActual)}`);
             this.raiseError(`verifyReferencesAtPositionListContains failed - could not find the item: ${stringify(missingItem)} in the returned list: (${stringify(references)})`);
         }
 
-        private getCompletionListAtCaret() {
-            return this.languageService.getCompletionsAtPosition(this.activeFile.fileName, this.currentCaretPosition);
+        private getCompletionListAtCaret(options?: ts.GetCompletionsAtPositionOptions): ts.CompletionInfo {
+            return this.languageService.getCompletionsAtPosition(this.activeFile.fileName, this.currentCaretPosition, options);
         }
 
-        private getCompletionEntryDetails(entryName: string, source?: string) {
+        private getCompletionEntryDetails(entryName: string, source?: string): ts.CompletionEntryDetails {
             return this.languageService.getCompletionEntryDetails(this.activeFile.fileName, this.currentCaretPosition, entryName, this.formatCodeSettings, source);
         }
 
@@ -1721,7 +1802,7 @@ Actual: ${stringify(fullActual)}`);
                     }
                     else if (prevChar === " " && /A-Za-z_/.test(ch)) {
                         /* Completions */
-                        this.languageService.getCompletionsAtPosition(this.activeFile.fileName, offset);
+                        this.languageService.getCompletionsAtPosition(this.activeFile.fileName, offset, { includeExternalModuleExports: false });
                     }
 
                     if (i % checkCadence === 0) {
@@ -2296,7 +2377,7 @@ Actual: ${stringify(fullActual)}`);
         public applyCodeActionFromCompletion(markerName: string, options: FourSlashInterface.VerifyCompletionActionOptions) {
             this.goToMarker(markerName);
 
-            const actualCompletion = this.getCompletionListAtCaret().entries.find(e => e.name === options.name && e.source === options.source);
+            const actualCompletion = this.getCompletionListAtCaret({ includeExternalModuleExports: true }).entries.find(e => e.name === options.name && e.source === options.source);
 
             if (!actualCompletion.hasAction) {
                 this.raiseError(`Completion for ${options.name} does not have an associated action.`);
@@ -3026,7 +3107,7 @@ Actual: ${stringify(fullActual)}`);
             this.raiseError(`Expected "${stringify({ entryId, text, documentation, kind })}" to be in list [${itemsString}]`);
         }
 
-        private findFile(indexOrName: any) {
+        private findFile(indexOrName: string | number) {
             let result: FourSlashFile;
             if (typeof indexOrName === "number") {
                 const index = <number>indexOrName;
@@ -3678,9 +3759,7 @@ namespace FourSlashInterface {
             this.state.goToImplementation();
         }
 
-        public position(position: number, fileIndex?: number): void;
-        public position(position: number, fileName?: string): void;
-        public position(position: number, fileNameOrIndex?: any): void {
+        public position(position: number, fileNameOrIndex?: string | number): void {
             if (fileNameOrIndex !== undefined) {
                 this.file(fileNameOrIndex);
             }
@@ -3690,9 +3769,7 @@ namespace FourSlashInterface {
         // Opens a file, given either its index as it
         // appears in the test source, or its filename
         // as specified in the test metadata
-        public file(index: number, content?: string, scriptKindName?: string): void;
-        public file(name: string, content?: string, scriptKindName?: string): void;
-        public file(indexOrName: any, content?: string, scriptKindName?: string): void {
+        public file(indexOrName: number | string, content?: string, scriptKindName?: string): void {
             this.state.openFile(indexOrName, content, scriptKindName);
         }
 
@@ -3734,15 +3811,15 @@ namespace FourSlashInterface {
 
         // Verifies the completion list contains the specified symbol. The
         // completion list is brought up if necessary
-        public completionListContains(entryId: string | ts.Completions.CompletionEntryIdentifier, text?: string, documentation?: string, kind?: string, spanIndex?: number, hasAction?: boolean) {
+        public completionListContains(entryId: string | ts.Completions.CompletionEntryIdentifier, text?: string, documentation?: string, kind?: string, spanIndex?: number, hasAction?: boolean, options?: ts.GetCompletionsAtPositionOptions) {
             if (typeof entryId === "string") {
                 entryId = { name: entryId, source: undefined };
             }
             if (this.negative) {
-                this.state.verifyCompletionListDoesNotContain(entryId, text, documentation, kind, spanIndex);
+                this.state.verifyCompletionListDoesNotContain(entryId, text, documentation, kind, spanIndex, options);
             }
             else {
-                this.state.verifyCompletionListContains(entryId, text, documentation, kind, spanIndex, hasAction);
+                this.state.verifyCompletionListContains(entryId, text, documentation, kind, spanIndex, hasAction, options);
             }
         }
 
@@ -3899,16 +3976,14 @@ namespace FourSlashInterface {
             this.state.verifyGoToDefinitionIs(endMarkers);
         }
 
-        public goToDefinition(startMarkerName: string | string[], endMarkerName: string | string[]): void;
-        public goToDefinition(startsAndEnds: [string | string[], string | string[]][]): void;
-        public goToDefinition(startsAndEnds: { [startMarkerName: string]: string | string[] }): void;
+        public goToDefinition(startMarkerName: string | string[], endMarkerName: string | string[], range?: FourSlash.Range): void;
+        public goToDefinition(startsAndEnds: [string | string[], string | string[]][] | { [startMarkerName: string]: string | string[] }): void;
         public goToDefinition(arg0: any, endMarkerName?: string | string[]) {
             this.state.verifyGoToDefinition(arg0, endMarkerName);
         }
 
         public goToType(startMarkerName: string | string[], endMarkerName: string | string[]): void;
-        public goToType(startsAndEnds: [string | string[], string | string[]][]): void;
-        public goToType(startsAndEnds: { [startMarkerName: string]: string | string[] }): void;
+        public goToType(startsAndEnds: [string | string[], string | string[]][] | { [startMarkerName: string]: string | string[] }): void;
         public goToType(arg0: any, endMarkerName?: string | string[]) {
             this.state.verifyGoToType(arg0, endMarkerName);
         }
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index c6caeff0dd9..8a3202b88be 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -479,7 +479,7 @@ namespace Utils {
 }
 
 namespace Harness {
-    export interface IO {
+    export interface Io {
         newLine(): string;
         getCurrentDirectory(): string;
         useCaseSensitiveFileNames(): boolean;
@@ -502,7 +502,7 @@ namespace Harness {
         tryEnableSourceMapsForHost?(): void;
         getEnvironmentVariable?(name: string): string;
     }
-    export let IO: IO;
+    export let IO: Io;
 
     // harness always uses one kind of new line
     // But note that `parseTestData` in `fourslash.ts` uses "\n"
@@ -555,8 +555,7 @@ namespace Harness {
                 try {
                     fs.unlinkSync(path);
                 }
-                catch (e) {
-                }
+                catch { /*ignore*/ }
             }
 
             export function directoryExists(path: string): boolean {
@@ -575,14 +574,13 @@ namespace Harness {
                 function filesInFolder(folder: string): string[] {
                     let paths: string[] = [];
 
-                    const files = fs.readdirSync(folder);
-                    for (let i = 0; i < files.length; i++) {
-                        const pathToFile = pathModule.join(folder, files[i]);
+                    for (const file of fs.readdirSync(folder)) {
+                        const pathToFile = pathModule.join(folder, file);
                         const stat = fs.statSync(pathToFile);
                         if (options.recursive && stat.isDirectory()) {
                             paths = paths.concat(filesInFolder(pathToFile));
                         }
-                        else if (stat.isFile() && (!spec || files[i].match(spec))) {
+                        else if (stat.isFile() && (!spec || file.match(spec))) {
                             paths.push(pathToFile);
                         }
                     }
@@ -616,7 +614,7 @@ namespace Harness {
 
             namespace Http {
                 function waitForXHR(xhr: XMLHttpRequest) {
-                    while (xhr.readyState !== 4) { }
+                    while (xhr.readyState !== 4) { } // tslint:disable-line no-empty
                     return { status: xhr.status, responseText: xhr.responseText };
                 }
 
@@ -784,9 +782,15 @@ namespace Harness {
         ? IO.newLine() + `//# sourceURL=${IO.resolvePath(tcServicesFileName)}`
         : "");
 
-    export interface SourceMapEmitterCallback {
-        (emittedFile: string, emittedLine: number, emittedColumn: number, sourceFile: string, sourceLine: number, sourceColumn: number, sourceName: string): void;
-    }
+    export type SourceMapEmitterCallback = (
+        emittedFile: string,
+        emittedLine: number,
+        emittedColumn: number,
+        sourceFile: string,
+        sourceLine: number,
+        sourceColumn: number,
+        sourceName: string,
+    ) => void;
 
     // Settings
     export let userSpecifiedRoot = "";
@@ -1108,11 +1112,11 @@ namespace Harness {
                 case "string":
                     return value;
                 case "number": {
-                    const number = parseInt(value, 10);
-                    if (isNaN(number)) {
+                    const numverValue = parseInt(value, 10);
+                    if (isNaN(numverValue)) {
                         throw new Error(`Value must be a number, got: ${JSON.stringify(value)}`);
                     }
-                    return number;
+                    return numverValue;
                 }
                 // If not a primitive, the possible types are specified in what is effectively a map of options.
                 case "list":
@@ -1319,7 +1323,7 @@ namespace Harness {
         export const diagnosticSummaryMarker = "__diagnosticSummary";
         export const globalErrorsMarker = "__globalErrors";
         export function *iterateErrorBaseline(inputFiles: ReadonlyArray<TestFile>, diagnostics: ReadonlyArray<ts.Diagnostic>, pretty?: boolean): IterableIterator<[string, string, number]> {
-            diagnostics = diagnostics.slice().sort(ts.compareDiagnostics);
+            diagnostics = ts.sort(diagnostics, ts.compareDiagnostics);
             let outputLines = "";
             // Count up all errors that were found in files other than lib.d.ts so we don't miss any
             let totalErrorsReportedInNonLibraryFiles = 0;
@@ -1575,10 +1579,8 @@ namespace Harness {
 
                     // Preserve legacy behavior
                     if (lastIndexWritten === undefined) {
-                        for (let i = 0; i < codeLines.length; i++) {
-                            const currentCodeLine = codeLines[i];
-                            typeLines += currentCodeLine + "\r\n";
-                            typeLines += "No type information for this code.";
+                        for (const codeLine of codeLines) {
+                            typeLines += codeLine + "\r\nNo type information for this code.";
                         }
                     }
                     else {
@@ -1704,7 +1706,7 @@ namespace Harness {
 
         export function *iterateOutputs(outputFiles: Harness.Compiler.GeneratedFile[]): IterableIterator<[string, string]> {
             // Collect, test, and sort the fileNames
-            outputFiles.sort((a, b) => ts.compareStrings(cleanName(a.fileName), cleanName(b.fileName)));
+            outputFiles.sort((a, b) => ts.compareStringsCaseSensitive(cleanName(a.fileName), cleanName(b.fileName)));
             const dupeCase = ts.createMap<number>();
             // Yield them
             for (const outputFile of outputFiles) {
@@ -1864,8 +1866,7 @@ namespace Harness {
             let currentFileName: any = undefined;
             let refs: string[] = [];
 
-            for (let i = 0; i < lines.length; i++) {
-                const line = lines[i];
+            for (const line of lines) {
                 const testMetaData = optionRegex.exec(line);
                 if (testMetaData) {
                     // Comment line, check for global/file @options and record them
@@ -1962,7 +1963,7 @@ namespace Harness {
 
     /** Support class for baseline files */
     export namespace Baseline {
-        const NoContent = "<no content>";
+        const noContent = "<no content>";
 
         export interface BaselineOptions {
             Subfolder?: string;
@@ -2021,7 +2022,7 @@ namespace Harness {
             /* tslint:disable:no-null-keyword */
             if (actual === null) {
             /* tslint:enable:no-null-keyword */
-                actual = NoContent;
+                actual = noContent;
             }
 
             let expected = "<no content>";
@@ -2058,13 +2059,13 @@ namespace Harness {
                 IO.deleteFile(actualFileName);
             }
 
-            const encoded_actual = Utils.encodeString(actual);
-            if (expected !== encoded_actual) {
-                if (actual === NoContent) {
+            const encodedActual = Utils.encodeString(actual);
+            if (expected !== encodedActual) {
+                if (actual === noContent) {
                     IO.writeFile(actualFileName + ".delete", "");
                 }
                 else {
-                    IO.writeFile(actualFileName, encoded_actual);
+                    IO.writeFile(actualFileName, encodedActual);
                 }
                 throw new Error(`The baseline file ${relativeFileName} has changed.`);
             }
@@ -2145,8 +2146,8 @@ namespace Harness {
         return filePath.indexOf(Harness.libFolder) === 0;
     }
 
-    export function getDefaultLibraryFile(io: Harness.IO): Harness.Compiler.TestFile {
-        const libFile = Harness.userSpecifiedRoot + Harness.libFolder + Harness.Compiler.defaultLibFileName;
+    export function getDefaultLibraryFile(filePath: string, io: Harness.Io): Harness.Compiler.TestFile {
+        const libFile = Harness.userSpecifiedRoot + Harness.libFolder + ts.getBaseFileName(ts.normalizeSlashes(filePath));
         return { unitName: libFile, content: io.readFile(libFile) };
     }
 
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index 64ef1b552f5..d4b5a9c2a16 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -108,7 +108,7 @@ namespace Harness.LanguageService {
     }
 
     class DefaultHostCancellationToken implements ts.HostCancellationToken {
-        public static readonly Instance = new DefaultHostCancellationToken();
+        public static readonly instance = new DefaultHostCancellationToken();
 
         public isCancellationRequested() {
             return false;
@@ -126,7 +126,7 @@ namespace Harness.LanguageService {
         public typesRegistry: ts.Map<void> | undefined;
         protected virtualFileSystem: Utils.VirtualFileSystem = new Utils.VirtualFileSystem(virtualFileSystemRoot, /*useCaseSensitiveFilenames*/false);
 
-        constructor(protected cancellationToken = DefaultHostCancellationToken.Instance,
+        constructor(protected cancellationToken = DefaultHostCancellationToken.instance,
             protected settings = ts.getDefaultCompilerOptions()) {
         }
 
@@ -166,8 +166,7 @@ namespace Harness.LanguageService {
             throw new Error("No script with name '" + fileName + "'");
         }
 
-        public openFile(_fileName: string, _content?: string, _scriptKindName?: string): void {
-        }
+        public openFile(_fileName: string, _content?: string, _scriptKindName?: string): void { /*overridden*/ }
 
         /**
          * @param line 0 based index
@@ -237,9 +236,9 @@ namespace Harness.LanguageService {
         }
 
 
-        log(_: string): void { }
-        trace(_: string): void { }
-        error(_: string): void { }
+        log = ts.noop;
+        trace = ts.noop;
+        error = ts.noop;
     }
 
     export class NativeLanguageServiceAdapter implements LanguageServiceAdapter {
@@ -413,11 +412,11 @@ namespace Harness.LanguageService {
         getEncodedSemanticClassifications(fileName: string, span: ts.TextSpan): ts.Classifications {
             return unwrapJSONCallResult(this.shim.getEncodedSemanticClassifications(fileName, span.start, span.length));
         }
-        getCompletionsAtPosition(fileName: string, position: number): ts.CompletionInfo {
-            return unwrapJSONCallResult(this.shim.getCompletionsAtPosition(fileName, position));
+        getCompletionsAtPosition(fileName: string, position: number, options: ts.GetCompletionsAtPositionOptions | undefined): ts.CompletionInfo {
+            return unwrapJSONCallResult(this.shim.getCompletionsAtPosition(fileName, position, options));
         }
-        getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: ts.FormatCodeOptions): ts.CompletionEntryDetails {
-            return unwrapJSONCallResult(this.shim.getCompletionEntryDetails(fileName, position, entryName, JSON.stringify(options)));
+        getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: ts.FormatCodeOptions | undefined, source: string | undefined): ts.CompletionEntryDetails {
+            return unwrapJSONCallResult(this.shim.getCompletionEntryDetails(fileName, position, entryName, JSON.stringify(options), source));
         }
         getCompletionEntrySymbol(): ts.Symbol {
             throw new Error("getCompletionEntrySymbol not implemented across the shim layer.");
@@ -443,6 +442,9 @@ namespace Harness.LanguageService {
         getDefinitionAtPosition(fileName: string, position: number): ts.DefinitionInfo[] {
             return unwrapJSONCallResult(this.shim.getDefinitionAtPosition(fileName, position));
         }
+        getDefinitionAndBoundSpan(fileName: string, position: number): ts.DefinitionInfoAndBoundSpan {
+            return unwrapJSONCallResult(this.shim.getDefinitionAndBoundSpan(fileName, position));
+        }
         getTypeDefinitionAtPosition(fileName: string, position: number): ts.DefinitionInfo[] {
             return unwrapJSONCallResult(this.shim.getTypeDefinitionAtPosition(fileName, position));
         }
@@ -492,7 +494,7 @@ namespace Harness.LanguageService {
         getFormattingEditsAfterKeystroke(fileName: string, position: number, key: string, options: ts.FormatCodeOptions): ts.TextChange[] {
             return unwrapJSONCallResult(this.shim.getFormattingEditsAfterKeystroke(fileName, position, key, JSON.stringify(options)));
         }
-        getDocCommentTemplateAtPosition(fileName: string, position: number): ts.TextInsertion {
+        getDocCommentTemplateAtPosition(fileName: string, position: number): ts.TextInsertion | undefined {
             return unwrapJSONCallResult(this.shim.getDocCommentTemplateAtPosition(fileName, position));
         }
         isValidBraceCompletionAtPosition(fileName: string, position: number, openingBrace: number): boolean {
@@ -541,9 +543,9 @@ namespace Harness.LanguageService {
         getClassifier(): ts.Classifier { return new ClassifierShimProxy(this.factory.createClassifierShim(this.host)); }
         getPreProcessedFileInfo(fileName: string, fileContents: string): ts.PreProcessedFileInfo {
             let shimResult: {
-                referencedFiles: ts.IFileReference[];
-                typeReferenceDirectives: ts.IFileReference[];
-                importedFiles: ts.IFileReference[];
+                referencedFiles: ts.ShimsFileReference[];
+                typeReferenceDirectives: ts.ShimsFileReference[];
+                importedFiles: ts.ShimsFileReference[];
                 isLibFile: boolean;
             };
 
@@ -593,13 +595,8 @@ namespace Harness.LanguageService {
             super(cancellationToken, settings);
         }
 
-        onMessage(): void {
-
-        }
-
-        writeMessage(): void {
-
-        }
+        onMessage = ts.noop;
+        writeMessage = ts.noop;
 
         setClient(client: ts.server.SessionClient) {
             this.client = client;
@@ -625,13 +622,8 @@ namespace Harness.LanguageService {
             this.newLine = this.host.getNewLine();
         }
 
-        onMessage(): void {
-
-        }
-
-        writeMessage(_message: string): void {
-        }
-
+        onMessage = ts.noop;
+        writeMessage = ts.noop; // overridden
         write(message: string): void {
             this.writeMessage(message);
         }
@@ -645,8 +637,7 @@ namespace Harness.LanguageService {
             return snapshot && snapshot.getText(0, snapshot.getLength());
         }
 
-        writeFile(): void {
-        }
+        writeFile = ts.noop;
 
         resolvePath(path: string): string {
             return path;
@@ -665,8 +656,7 @@ namespace Harness.LanguageService {
             return "";
         }
 
-        exit(): void {
-        }
+        exit = ts.noop;
 
         createDirectory(_directoryName: string): void {
             return ts.notImplemented();
@@ -694,8 +684,7 @@ namespace Harness.LanguageService {
             return { close: ts.noop };
         }
 
-        close(): void {
-        }
+        close = ts.noop;
 
         info(message: string): void {
             this.host.log(message);
@@ -754,6 +743,7 @@ namespace Harness.LanguageService {
                             create(info: ts.server.PluginCreateInfo) {
                                 const proxy = makeDefaultProxy(info);
                                 const langSvc: any = info.languageService;
+                                // tslint:disable-next-line only-arrow-functions
                                 proxy.getQuickInfoAtPosition = function () {
                                     const parts = langSvc.getQuickInfoAtPosition.apply(langSvc, arguments);
                                     if (parts.displayParts.length > 0) {
@@ -786,7 +776,7 @@ namespace Harness.LanguageService {
                         module: () => ({
                             create(info: ts.server.PluginCreateInfo) {
                                 const proxy = makeDefaultProxy(info);
-                                proxy.getSemanticDiagnostics = function (filename: string) {
+                                proxy.getSemanticDiagnostics = filename => {
                                     const prev = info.languageService.getSemanticDiagnostics(filename);
                                     const sourceFile: ts.SourceFile = info.languageService.getSourceFile(filename);
                                     prev.push({
@@ -812,11 +802,12 @@ namespace Harness.LanguageService {
                     };
             }
 
-            function makeDefaultProxy(info: ts.server.PluginCreateInfo) {
+            function makeDefaultProxy(info: ts.server.PluginCreateInfo): ts.LanguageService {
                 // tslint:disable-next-line:no-null-keyword
                 const proxy = Object.create(/*prototype*/ null);
                 const langSvc: any = info.languageService;
                 for (const k of Object.keys(langSvc)) {
+                    // tslint:disable-next-line only-arrow-functions
                     proxy[k] = function () {
                         return langSvc[k].apply(langSvc, arguments);
                     };
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index fcc163e77f3..37e8dddb3d7 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -14,19 +14,19 @@ interface FileInformation {
 interface FindFileResult {
 }
 
-interface IOLogFile {
+interface IoLogFile {
     path: string;
     codepage: number;
     result?: FileInformation;
 }
 
-interface IOLog {
+interface IoLog {
     timestamp: string;
     arguments: string[];
     executingPath: string;
     currentDirectory: string;
     useCustomLibraryFile?: boolean;
-    filesRead: IOLogFile[];
+    filesRead: IoLogFile[];
     filesWritten: {
         path: string;
         contents?: string;
@@ -80,16 +80,16 @@ interface IOLog {
 interface PlaybackControl {
     startReplayFromFile(logFileName: string): void;
     startReplayFromString(logContents: string): void;
-    startReplayFromData(log: IOLog): void;
+    startReplayFromData(log: IoLog): void;
     endReplay(): void;
     startRecord(logFileName: string): void;
     endRecord(): void;
 }
 
 namespace Playback {
-    let recordLog: IOLog = undefined;
-    let replayLog: IOLog = undefined;
-    let replayFilesRead: ts.Map<IOLogFile> | undefined = undefined;
+    let recordLog: IoLog = undefined;
+    let replayLog: IoLog = undefined;
+    let replayFilesRead: ts.Map<IoLogFile> | undefined = undefined;
     let recordLogFileNameBase = "";
 
     interface Memoized<T> {
@@ -110,11 +110,11 @@ namespace Playback {
         return run;
     }
 
-    export interface PlaybackIO extends Harness.IO, PlaybackControl { }
+    export interface PlaybackIO extends Harness.Io, PlaybackControl { }
 
     export interface PlaybackSystem extends ts.System, PlaybackControl { }
 
-    function createEmptyLog(): IOLog {
+    function createEmptyLog(): IoLog {
         return {
             timestamp: (new Date()).toString(),
             arguments: [],
@@ -134,7 +134,7 @@ namespace Playback {
         };
     }
 
-    export function newStyleLogIntoOldStyleLog(log: IOLog, host: ts.System | Harness.IO, baseName: string) {
+    export function newStyleLogIntoOldStyleLog(log: IoLog, host: ts.System | Harness.Io, baseName: string) {
         for (const file of log.filesAppended) {
             if (file.contentsPath) {
                 file.contents = host.readFile(ts.combinePaths(baseName, file.contentsPath));
@@ -167,7 +167,7 @@ namespace Playback {
         return path;
     }
 
-    export function oldStyleLogIntoNewStyleLog(log: IOLog, writeFile: typeof Harness.IO.writeFile, baseTestName: string) {
+    export function oldStyleLogIntoNewStyleLog(log: IoLog, writeFile: typeof Harness.IO.writeFile, baseTestName: string) {
         if (log.filesAppended) {
             for (const file of log.filesAppended) {
                 if (file.contents !== undefined) {
@@ -210,8 +210,8 @@ namespace Playback {
     }
 
     function initWrapper(wrapper: PlaybackSystem, underlying: ts.System): void;
-    function initWrapper(wrapper: PlaybackIO, underlying: Harness.IO): void;
-    function initWrapper(wrapper: PlaybackSystem | PlaybackIO, underlying: ts.System | Harness.IO): void {
+    function initWrapper(wrapper: PlaybackIO, underlying: Harness.Io): void;
+    function initWrapper(wrapper: PlaybackSystem | PlaybackIO, underlying: ts.System | Harness.Io): void {
         ts.forEach(Object.keys(underlying), prop => {
             (<any>wrapper)[prop] = (<any>underlying)[prop];
         });
@@ -249,13 +249,33 @@ namespace Playback {
         wrapper.endRecord = () => {
             if (recordLog !== undefined) {
                 let i = 0;
-                const fn = () => recordLogFileNameBase + i;
-                while (underlying.fileExists(ts.combinePaths(fn(), "test.json"))) i++;
-                underlying.writeFile(ts.combinePaths(fn(), "test.json"), JSON.stringify(oldStyleLogIntoNewStyleLog(recordLog, (path, string) => underlying.writeFile(path, string), fn()), null, 4)); // tslint:disable-line:no-null-keyword
+                const getBase = () => recordLogFileNameBase + i;
+                while (underlying.fileExists(ts.combinePaths(getBase(), "test.json"))) i++;
+                const newLog = oldStyleLogIntoNewStyleLog(recordLog, (path, str) => underlying.writeFile(path, str), getBase());
+                underlying.writeFile(ts.combinePaths(getBase(), "test.json"), JSON.stringify(newLog, null, 4)); // tslint:disable-line:no-null-keyword
+                const syntheticTsconfig = generateTsconfig(newLog);
+                if (syntheticTsconfig) {
+                    underlying.writeFile(ts.combinePaths(getBase(), "tsconfig.json"), JSON.stringify(syntheticTsconfig, null, 4)); // tslint:disable-line:no-null-keyword
+                }
                 recordLog = undefined;
             }
         };
 
+        function generateTsconfig(newLog: IoLog): undefined | { compilerOptions: ts.CompilerOptions, files: string[] } {
+            if (newLog.filesRead.some(file => /tsconfig.+json$/.test(file.path))) {
+                return;
+            }
+            const files = [];
+            for (const file of newLog.filesRead) {
+                if (file.result.contentsPath &&
+                    Harness.isDefaultLibraryFile(file.result.contentsPath) &&
+                    /\.[tj]s$/.test(file.result.contentsPath)) {
+                    files.push(file.result.contentsPath);
+                }
+            }
+            return { compilerOptions: ts.parseCommandLine(newLog.arguments).options, files };
+        }
+
         wrapper.fileExists = recordReplay(wrapper.fileExists, underlying)(
             path => callAndRecord(underlying.fileExists(path), recordLog.fileExists, { path }),
             memoize(path => {
@@ -346,6 +366,7 @@ namespace Playback {
 
     function recordReplay<T extends Function>(original: T, underlying: any) {
         function createWrapper(record: T, replay: T): T {
+            // tslint:disable-next-line only-arrow-functions
             return <any>(function () {
                 if (replayLog !== undefined) {
                     return replay.apply(undefined, arguments);
@@ -406,7 +427,7 @@ namespace Playback {
         // console.log("Swallowed write operation during replay: " + name);
     }
 
-    export function wrapIO(underlying: Harness.IO): PlaybackIO {
+    export function wrapIO(underlying: Harness.Io): PlaybackIO {
         const wrapper: PlaybackIO = <any>{};
         initWrapper(wrapper, underlying);
 
diff --git a/src/harness/parallel/host.ts b/src/harness/parallel/host.ts
index bf218c1b3a1..e278d267e1f 100644
--- a/src/harness/parallel/host.ts
+++ b/src/harness/parallel/host.ts
@@ -77,18 +77,18 @@ namespace Harness.Parallel.Host {
         console.log("Discovering runner-based tests...");
         const discoverStart = +(new Date());
         const { statSync }: { statSync(path: string): { size: number }; } = require("fs");
+        const path: { join: (...args: string[]) => string } = require("path");
         for (const runner of runners) {
-            const files = runner.enumerateTestFiles();
-            for (const file of files) {
+            for (const file of runner.enumerateTestFiles()) {
                 let size: number;
                 if (!perfData) {
                     try {
-                        size = statSync(file).size;
+                        size = statSync(path.join(runner.workingDirectory, file)).size;
                     }
                     catch {
                         // May be a directory
                         try {
-                            size = Harness.IO.listFiles(file, /.*/g, { recursive: true }).reduce((acc, elem) => acc + statSync(elem).size, 0);
+                            size = Harness.IO.listFiles(path.join(runner.workingDirectory, file), /.*/g, { recursive: true }).reduce((acc, elem) => acc + statSync(elem).size, 0);
                         }
                         catch {
                             // Unknown test kind, just return 0 and let the historical analysis take over after one run
@@ -274,15 +274,15 @@ namespace Harness.Parallel.Host {
         function completeBar() {
             const isPartitionFail = failingFiles !== 0;
             const summaryColor = isPartitionFail ? "fail" : "green";
-            const summarySymbol = isPartitionFail ? Base.symbols.err : Base.symbols.ok;
+            const summarySymbol = isPartitionFail ? base.symbols.err : base.symbols.ok;
 
             const summaryTests = (isPartitionFail ? totalPassing + "/" + (errorResults.length + totalPassing) : totalPassing) + " passing";
             const summaryDuration = "(" + ms(duration) + ")";
-            const savedUseColors = Base.useColors;
-            Base.useColors = !noColors;
+            const savedUseColors = base.useColors;
+            base.useColors = !noColors;
 
             const summary = color(summaryColor, summarySymbol + " " + summaryTests) + " " + color("light", summaryDuration);
-            Base.useColors = savedUseColors;
+            base.useColors = savedUseColors;
 
             updateProgress(1, summary);
         }
@@ -307,22 +307,21 @@ namespace Harness.Parallel.Host {
             completeBar();
             progressBars.disable();
 
-            const reporter = new Base();
+            const reporter = new base();
             const stats = reporter.stats;
             const failures = reporter.failures;
             stats.passes = totalPassing;
             stats.failures = errorResults.length;
             stats.tests = totalPassing + errorResults.length;
             stats.duration = duration;
-            for (let j = 0; j < errorResults.length; j++) {
-                const failure = errorResults[j];
+            for (const failure of errorResults) {
                 failures.push(makeMochaTest(failure));
             }
             if (noColors) {
-                const savedUseColors = Base.useColors;
-                Base.useColors = false;
+                const savedUseColors = base.useColors;
+                base.useColors = false;
                 reporter.epilogue();
-                Base.useColors = savedUseColors;
+                base.useColors = savedUseColors;
             }
             else {
                 reporter.epilogue();
@@ -353,8 +352,8 @@ namespace Harness.Parallel.Host {
         return;
     }
 
-    let Mocha: any;
-    let Base: any;
+    let mocha: any;
+    let base: any;
     let color: any;
     let cursor: any;
     let readline: any;
@@ -395,10 +394,10 @@ namespace Harness.Parallel.Host {
     }
 
     function initializeProgressBarsDependencies() {
-        Mocha = require("mocha");
-        Base = Mocha.reporters.Base;
-        color = Base.color;
-        cursor = Base.cursor;
+        mocha = require("mocha");
+        base = mocha.reporters.Base;
+        color = base.color;
+        cursor = base.cursor;
         readline = require("readline");
         os = require("os");
         tty = require("tty");
@@ -415,8 +414,8 @@ namespace Harness.Parallel.Host {
             const open = options.open || "[";
             const close = options.close || "]";
             const complete = options.complete || "▬";
-            const incomplete = options.incomplete || Base.symbols.dot;
-            const maxWidth = Base.window.width - open.length - close.length - 34;
+            const incomplete = options.incomplete || base.symbols.dot;
+            const maxWidth = base.window.width - open.length - close.length - 34;
             const width = minMax(options.width || maxWidth, 10, maxWidth);
             this._options = {
                 open,
diff --git a/src/harness/parallel/worker.ts b/src/harness/parallel/worker.ts
index c32b9660a39..953ed5aeb21 100644
--- a/src/harness/parallel/worker.ts
+++ b/src/harness/parallel/worker.ts
@@ -57,7 +57,9 @@ namespace Harness.Parallel.Worker {
             return cleanup();
         }
         try {
-            beforeFunc && beforeFunc();
+            if (beforeFunc) {
+                beforeFunc();
+            }
         }
         catch (e) {
             errors.push({ error: `Error executing before function: ${e.message}`, stack: e.stack, name: [...namestack] });
@@ -69,7 +71,9 @@ namespace Harness.Parallel.Worker {
         testList.forEach(({ name, callback, kind }) => executeCallback(name, callback, kind));
 
         try {
-            afterFunc && afterFunc();
+            if (afterFunc) {
+                afterFunc();
+            }
         }
         catch (e) {
             errors.push({ error: `Error executing after function: ${e.message}`, stack: e.stack, name: [...namestack] });
diff --git a/src/harness/projectsRunner.ts b/src/harness/projectsRunner.ts
index cc68f8625f4..c617cc7a0a3 100644
--- a/src/harness/projectsRunner.ts
+++ b/src/harness/projectsRunner.ts
@@ -140,12 +140,12 @@ class ProjectRunner extends RunnerBase {
 
             // Clean up source map data that will be used in baselining
             if (sourceMapData) {
-                for (let i = 0; i < sourceMapData.length; i++) {
-                    for (let j = 0; j < sourceMapData[i].sourceMapSources.length; j++) {
-                        sourceMapData[i].sourceMapSources[j] = cleanProjectUrl(sourceMapData[i].sourceMapSources[j]);
+                for (const data of sourceMapData) {
+                    for (let j = 0; j < data.sourceMapSources.length; j++) {
+                        data.sourceMapSources[j] = cleanProjectUrl(data.sourceMapSources[j]);
                     }
-                    sourceMapData[i].jsSourceMappingURL = cleanProjectUrl(sourceMapData[i].jsSourceMappingURL);
-                    sourceMapData[i].sourceMapSourceRoot = cleanProjectUrl(sourceMapData[i].sourceMapSourceRoot);
+                    data.jsSourceMappingURL = cleanProjectUrl(data.jsSourceMappingURL);
+                    data.sourceMapSourceRoot = cleanProjectUrl(data.sourceMapSourceRoot);
                 }
             }
 
@@ -396,7 +396,7 @@ class ProjectRunner extends RunnerBase {
             });
 
             // Dont allow config files since we are compiling existing source options
-            return compileProjectFiles(compilerResult.moduleKind, compilerResult.configFileSourceFiles, getInputFiles, getSourceFileText, writeFile, compilerResult.compilerOptions);
+            return compileProjectFiles(compilerResult.moduleKind, compilerResult.configFileSourceFiles, getInputFiles, getSourceFileText, /*writeFile*/ ts.noop, compilerResult.compilerOptions);
 
             function findOutputDtsFile(fileName: string) {
                 return ts.forEach(compilerResult.outputFiles, outputFile => outputFile.emittedFileName === fileName ? outputFile : undefined);
@@ -416,9 +416,6 @@ class ProjectRunner extends RunnerBase {
                 }
                 return undefined;
             }
-
-            function writeFile() {
-            }
         }
 
         function getErrorsBaseline(compilerResult: CompileProjectFilesResult) {
diff --git a/src/harness/runner.ts b/src/harness/runner.ts
index db807b976bb..2bd098b742d 100644
--- a/src/harness/runner.ts
+++ b/src/harness/runner.ts
@@ -18,6 +18,7 @@
 /// <reference path="fourslashRunner.ts" />
 /// <reference path="projectsRunner.ts" />
 /// <reference path="rwcRunner.ts" />
+/// <reference path="externalCompileRunner.ts" />
 /// <reference path="harness.ts" />
 /// <reference path="./parallel/shared.ts" />
 
@@ -26,8 +27,8 @@ let iterations = 1;
 
 function runTests(runners: RunnerBase[]) {
     for (let i = iterations; i > 0; i--) {
-        for (let j = 0; j < runners.length; j++) {
-            runners[j].initializeTests();
+        for (const runner of runners) {
+            runner.initializeTests();
         }
     }
 }
@@ -59,6 +60,10 @@ function createRunner(kind: TestRunnerKind): RunnerBase {
             return new RWCRunner();
         case "test262":
             return new Test262BaselineRunner();
+        case "user":
+            return new UserCodeRunner();
+        case "dt":
+            return new DefinitelyTypedRunner();
     }
     ts.Debug.fail(`Unknown runner kind ${kind}`);
 }
@@ -92,6 +97,7 @@ interface TestConfig {
     workerCount?: number;
     stackTraceLimit?: number | "full";
     test?: string[];
+    runners?: string[];
     runUnitTests?: boolean;
     noColors?: boolean;
 }
@@ -129,8 +135,9 @@ function handleTestConfig() {
             return true;
         }
 
-        if (testConfig.test && testConfig.test.length > 0) {
-            for (const option of testConfig.test) {
+        const runnerConfig = testConfig.runners || testConfig.test;
+        if (runnerConfig && runnerConfig.length > 0) {
+            for (const option of runnerConfig) {
                 if (!option) {
                     continue;
                 }
@@ -175,6 +182,12 @@ function handleTestConfig() {
                     case "test262":
                         runners.push(new Test262BaselineRunner());
                         break;
+                    case "user":
+                        runners.push(new UserCodeRunner());
+                        break;
+                    case "dt":
+                        runners.push(new DefinitelyTypedRunner());
+                        break;
                 }
             }
         }
@@ -196,6 +209,11 @@ function handleTestConfig() {
         runners.push(new FourSlashRunner(FourSlashTestType.ShimsWithPreprocess));
         runners.push(new FourSlashRunner(FourSlashTestType.Server));
         // runners.push(new GeneratedFourslashRunner());
+
+        // CRON-only tests
+        if (Utils.getExecutionEnvironment() !== Utils.ExecutionEnvironment.Browser && process.env.TRAVIS_EVENT_TYPE === "cron") {
+            runners.push(new UserCodeRunner());
+        }
     }
     if (runUnitTests === undefined) {
         runUnitTests = runners.length !== 1; // Don't run unit tests when running only one runner if unit tests were not explicitly asked for
@@ -207,6 +225,14 @@ function beginTests() {
         ts.Debug.enableDebugInfo();
     }
 
+    // run tests in en-US by default.
+    let savedUILocale: string | undefined;
+    beforeEach(() => {
+        savedUILocale = ts.getUILocale();
+        ts.setUILocale("en-US");
+    });
+    afterEach(() => ts.setUILocale(savedUILocale));
+
     runTests(runners);
 
     if (!runUnitTests) {
@@ -215,8 +241,9 @@ function beginTests() {
     }
 }
 
+let isWorker: boolean;
 function startTestEnvironment() {
-    const isWorker = handleTestConfig();
+    isWorker = handleTestConfig();
     if (Utils.getExecutionEnvironment() !== Utils.ExecutionEnvironment.Browser) {
         if (isWorker) {
             return Harness.Parallel.Worker.start();
diff --git a/src/harness/runnerbase.ts b/src/harness/runnerbase.ts
index d50604803ed..80532d30b6f 100644
--- a/src/harness/runnerbase.ts
+++ b/src/harness/runnerbase.ts
@@ -1,13 +1,11 @@
 /// <reference path="harness.ts" />
 
 
-type TestRunnerKind = CompilerTestKind | FourslashTestKind | "project" | "rwc" | "test262";
+type TestRunnerKind = CompilerTestKind | FourslashTestKind | "project" | "rwc" | "test262" | "user" | "dt";
 type CompilerTestKind = "conformance" | "compiler";
 type FourslashTestKind = "fourslash" | "fourslash-shims" | "fourslash-shims-pp" | "fourslash-server";
 
 abstract class RunnerBase {
-    constructor() { }
-
     // contains the tests to run
     public tests: string[] = [];
 
@@ -24,6 +22,9 @@ abstract class RunnerBase {
 
     abstract enumerateTestFiles(): string[];
 
+    /** The working directory where tests are found. Needed for batch testing where the input path will differ from the output path inside baselines */
+    public workingDirectory = "";
+
     /** Setup the runner's tests so that they are ready to be executed by the harness
      *  The first test should be a describe/it block that sets up the harness's compiler instance appropriately
      */
diff --git a/src/harness/rwcRunner.ts b/src/harness/rwcRunner.ts
index 2b4fc7b24e4..ef7a371b0c4 100644
--- a/src/harness/rwcRunner.ts
+++ b/src/harness/rwcRunner.ts
@@ -6,7 +6,7 @@
 /* tslint:disable:no-null-keyword */
 
 namespace RWC {
-    function runWithIOLog(ioLog: IOLog, fn: (oldIO: Harness.IO) => void) {
+    function runWithIOLog(ioLog: IoLog, fn: (oldIO: Harness.Io) => void) {
         const oldIO = Harness.IO;
 
         const wrappedIO = Playback.wrapIO(oldIO);
@@ -58,7 +58,7 @@ namespace RWC {
                 this.timeout(800000); // Allow long timeouts for RWC compilations
                 let opts: ts.ParsedCommandLine;
 
-                const ioLog: IOLog = Playback.newStyleLogIntoOldStyleLog(JSON.parse(Harness.IO.readFile(`internal/cases/rwc/${jsonPath}/test.json`)), Harness.IO, `internal/cases/rwc/${baseName}`);
+                const ioLog: IoLog = Playback.newStyleLogIntoOldStyleLog(JSON.parse(Harness.IO.readFile(`internal/cases/rwc/${jsonPath}/test.json`)), Harness.IO, `internal/cases/rwc/${baseName}`);
                 currentDirectory = ioLog.currentDirectory;
                 useCustomLibraryFile = ioLog.useCustomLibraryFile;
                 runWithIOLog(ioLog, () => {
@@ -131,13 +131,14 @@ namespace RWC {
                                 }
                                 else {
                                     // set the flag to put default library to the beginning of the list
-                                    inputFiles.unshift(Harness.getDefaultLibraryFile(oldIO));
+                                    inputFiles.unshift(Harness.getDefaultLibraryFile(fileRead.path, oldIO));
                                 }
                             }
                         }
                     }
 
                     // do not use lib since we already read it in above
+                    opts.options.lib = undefined;
                     opts.options.noLib = true;
 
                     // Emit the results
@@ -245,10 +246,8 @@ class RWCRunner extends RunnerBase {
      */
     public initializeTests(): void {
         // Read in and evaluate the test list
-        const testList = this.tests && this.tests.length ? this.tests : this.enumerateTestFiles();
-
-        for (let i = 0; i < testList.length; i++) {
-            this.runTest(testList[i]);
+        for (const test of this.tests && this.tests.length ? this.tests : this.enumerateTestFiles()) {
+            this.runTest(test);
         }
     }
 
diff --git a/src/harness/sourceMapRecorder.ts b/src/harness/sourceMapRecorder.ts
index de068706fbe..606d4e67acd 100644
--- a/src/harness/sourceMapRecorder.ts
+++ b/src/harness/sourceMapRecorder.ts
@@ -386,9 +386,9 @@ namespace Harness.SourceMapRecorder {
 
                 if (currentSpan.decodeErrors) {
                     // If there are decode errors, write
-                    for (let i = 0; i < currentSpan.decodeErrors.length; i++) {
+                    for (const decodeError of currentSpan.decodeErrors) {
                         writeSourceMapIndent(prevEmittedCol, markerIds[index]);
-                        sourceMapRecorder.WriteLine(currentSpan.decodeErrors[i]);
+                        sourceMapRecorder.WriteLine(decodeError);
                     }
                 }
 
@@ -442,8 +442,7 @@ namespace Harness.SourceMapRecorder {
             let prevSourceFile: ts.SourceFile;
 
             SourceMapSpanWriter.initializeSourceMapSpanWriter(sourceMapRecorder, sourceMapData, jsFiles[i]);
-            for (let j = 0; j < sourceMapData.sourceMapDecodedMappings.length; j++) {
-                const decodedSourceMapping = sourceMapData.sourceMapDecodedMappings[j];
+            for (const decodedSourceMapping of sourceMapData.sourceMapDecodedMappings) {
                 const currentSourceFile = program.getSourceFile(sourceMapData.inputSourceFileNames[decodedSourceMapping.sourceIndex]);
                 if (currentSourceFile !== prevSourceFile) {
                     SourceMapSpanWriter.recordNewSourceFileSpan(decodedSourceMapping, currentSourceFile.text);
diff --git a/src/harness/tsconfig.json b/src/harness/tsconfig.json
index 18baeb67c82..db38b95ba6a 100644
--- a/src/harness/tsconfig.json
+++ b/src/harness/tsconfig.json
@@ -60,20 +60,11 @@
         "../services/jsTyping.ts",
         "../services/formatting/formatting.ts",
         "../services/formatting/formattingContext.ts",
-        "../services/formatting/formattingRequestKind.ts",
         "../services/formatting/formattingScanner.ts",
-        "../services/formatting/references.ts",
         "../services/formatting/rule.ts",
-        "../services/formatting/ruleAction.ts",
-        "../services/formatting/ruleDescriptor.ts",
-        "../services/formatting/ruleFlag.ts",
-        "../services/formatting/ruleOperation.ts",
-        "../services/formatting/ruleOperationContext.ts",
         "../services/formatting/rules.ts",
         "../services/formatting/rulesMap.ts",
-        "../services/formatting/rulesProvider.ts",
         "../services/formatting/smartIndenter.ts",
-        "../services/formatting/tokenRange.ts",
         "../services/codeFixProvider.ts",
         "../services/codefixes/fixes.ts",
         "../services/codefixes/helpers.ts",
@@ -92,6 +83,7 @@
         "projectsRunner.ts",
         "loggedIO.ts",
         "rwcRunner.ts",
+        "externalCompileRunner.ts",
         "test262Runner.ts",
         "./parallel/shared.ts",
         "./parallel/host.ts",
diff --git a/src/harness/typeWriter.ts b/src/harness/typeWriter.ts
index af626f1e548..17eda776bda 100644
--- a/src/harness/typeWriter.ts
+++ b/src/harness/typeWriter.ts
@@ -52,7 +52,7 @@ class TypeWriterWalker {
     }
 
     private *visitNode(node: ts.Node, isSymbolWalk: boolean): IterableIterator<TypeWriterResult> {
-        if (ts.isPartOfExpression(node) || node.kind === ts.SyntaxKind.Identifier) {
+        if (ts.isExpressionNode(node) || node.kind === ts.SyntaxKind.Identifier) {
             const result = this.writeTypeOrSymbol(node, isSymbolWalk);
             if (result) {
                 yield result;
diff --git a/src/harness/unittests/commandLineParsing.ts b/src/harness/unittests/commandLineParsing.ts
index 01a208aa330..18e867cb9ea 100644
--- a/src/harness/unittests/commandLineParsing.ts
+++ b/src/harness/unittests/commandLineParsing.ts
@@ -60,7 +60,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,invalidOption", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -263,7 +263,7 @@ namespace ts {
             assertParseResult(["--lib", "es5,", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
@@ -283,7 +283,7 @@ namespace ts {
             assertParseResult(["--lib", "es5, ", "es7", "0.ts"],
                 {
                     errors: [{
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         category: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.category,
                         code: ts.Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
 
diff --git a/src/harness/unittests/compileOnSave.ts b/src/harness/unittests/compileOnSave.ts
index 7be6ab5b323..7ef3e2aa1af 100644
--- a/src/harness/unittests/compileOnSave.ts
+++ b/src/harness/unittests/compileOnSave.ts
@@ -13,8 +13,8 @@ namespace ts.projectSystem {
     describe("CompileOnSave affected list", () => {
         function sendAffectedFileRequestAndCheckResult(session: server.Session, request: server.protocol.Request, expectedFileList: { projectFileName: string, files: FileOrFolder[] }[]) {
             const response = session.executeCommand(request).response as server.protocol.CompileOnSaveAffectedFileListSingleProject[];
-            const actualResult = response.sort((list1, list2) => compareStrings(list1.projectFileName, list2.projectFileName));
-            expectedFileList = expectedFileList.sort((list1, list2) => compareStrings(list1.projectFileName, list2.projectFileName));
+            const actualResult = response.sort((list1, list2) => ts.compareStringsCaseSensitive(list1.projectFileName, list2.projectFileName));
+            expectedFileList = expectedFileList.sort((list1, list2) => ts.compareStringsCaseSensitive(list1.projectFileName, list2.projectFileName));
 
             assert.equal(actualResult.length, expectedFileList.length, `Actual result project number is different from the expected project number`);
 
@@ -627,8 +627,8 @@ namespace ts.projectSystem {
             const mapFileContent = host.readFile(expectedMapFileName);
             verifyContentHasString(mapFileContent, `"sources":["${inputFileName}"]`);
 
-            function verifyContentHasString(content: string, string: string) {
-                assert.isTrue(content.indexOf(string) !== -1, `Expected "${content}" to have "${string}"`);
+            function verifyContentHasString(content: string, str: string) {
+                assert.isTrue(stringContains(content, str), `Expected "${content}" to have "${str}"`);
             }
         });
     });
diff --git a/src/harness/unittests/configurationExtension.ts b/src/harness/unittests/configurationExtension.ts
index 0032505aba1..5a1b155fbcf 100644
--- a/src/harness/unittests/configurationExtension.ts
+++ b/src/harness/unittests/configurationExtension.ts
@@ -25,9 +25,9 @@ namespace ts {
         },
         "/dev/configs/tests.json": {
             compilerOptions: {
-                "preserveConstEnums": true,
-                "removeComments": false,
-                "sourceMap": true
+                preserveConstEnums: true,
+                removeComments: false,
+                sourceMap: true
             },
             exclude: [
                 "../tests/baselines",
@@ -52,7 +52,7 @@ namespace ts {
         "/dev/missing.json": {
             extends: "./missing2",
             compilerOptions: {
-                "types": []
+                types: []
             }
         },
         "/dev/failure.json": {
diff --git a/src/harness/unittests/convertCompilerOptionsFromJson.ts b/src/harness/unittests/convertCompilerOptionsFromJson.ts
index c55dee26dc4..3a73971d7a3 100644
--- a/src/harness/unittests/convertCompilerOptionsFromJson.ts
+++ b/src/harness/unittests/convertCompilerOptionsFromJson.ts
@@ -58,12 +58,12 @@ namespace ts {
         it("Convert correctly format tsconfig.json to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": ["es5", "es2015.core", "es2015.symbol"]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: ["es5", "es2015.core", "es2015.symbol"]
                     }
                 }, "tsconfig.json",
                 {
@@ -82,13 +82,13 @@ namespace ts {
         it("Convert correctly format tsconfig.json with allowJs is false to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "allowJs": false,
-                        "lib": ["es5", "es2015.core", "es2015.symbol"]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        allowJs: false,
+                        lib: ["es5", "es2015.core", "es2015.symbol"]
                     }
                 }, "tsconfig.json",
                 {
@@ -108,12 +108,12 @@ namespace ts {
         it("Convert incorrect option of jsx to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "jsx": ""
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        jsx: ""
                     }
                 }, "tsconfig.json",
                 {
@@ -138,11 +138,11 @@ namespace ts {
         it("Convert incorrect option of module to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
+                    compilerOptions: {
+                        module: "",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
                     }
                 }, "tsconfig.json",
                 {
@@ -166,11 +166,11 @@ namespace ts {
         it("Convert incorrect option of newLine to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "newLine": "",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
+                    compilerOptions: {
+                        newLine: "",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
                     }
                 }, "tsconfig.json",
                 {
@@ -194,10 +194,10 @@ namespace ts {
         it("Convert incorrect option of target to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "target": "",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
+                    compilerOptions: {
+                        target: "",
+                        noImplicitAny: false,
+                        sourceMap: false,
                     }
                 }, "tsconfig.json",
                 {
@@ -220,10 +220,10 @@ namespace ts {
         it("Convert incorrect option of module-resolution to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "moduleResolution": "",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
+                    compilerOptions: {
+                        moduleResolution: "",
+                        noImplicitAny: false,
+                        sourceMap: false,
                     }
                 }, "tsconfig.json",
                 {
@@ -246,12 +246,12 @@ namespace ts {
         it("Convert incorrect option of libs to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": ["es5", "es2015.core", "incorrectLib"]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: ["es5", "es2015.core", "incorrectLib"]
                     }
                 }, "tsconfig.json",
                 {
@@ -266,7 +266,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -277,12 +277,12 @@ namespace ts {
         it("Convert empty string option of libs to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": ["es5", ""]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: ["es5", ""]
                     }
                 }, "tsconfig.json",
                 {
@@ -297,7 +297,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -308,12 +308,12 @@ namespace ts {
         it("Convert empty string option of libs to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": [""]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: [""]
                     }
                 }, "tsconfig.json",
                 {
@@ -328,7 +328,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -339,12 +339,12 @@ namespace ts {
         it("Convert trailing-whitespace string option of libs to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": ["   "]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: ["   "]
                     }
                 }, "tsconfig.json",
                 {
@@ -359,7 +359,7 @@ namespace ts {
                         file: undefined,
                         start: 0,
                         length: 0,
-                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'esnext.asynciterable'.",
+                        messageText: "Argument for '--lib' option must be: 'es5', 'es6', 'es2015', 'es7', 'es2016', 'es2017', 'esnext', 'dom', 'dom.iterable', 'webworker', 'scripthost', 'es2015.core', 'es2015.collection', 'es2015.generator', 'es2015.iterable', 'es2015.promise', 'es2015.proxy', 'es2015.reflect', 'es2015.symbol', 'es2015.symbol.wellknown', 'es2016.array.include', 'es2017.object', 'es2017.sharedmemory', 'es2017.string', 'es2017.intl', 'es2017.typedarrays', 'esnext.asynciterable'.",
                         code: Diagnostics.Argument_for_0_option_must_be_Colon_1.code,
                         category: Diagnostics.Argument_for_0_option_must_be_Colon_1.category
                     }]
@@ -370,12 +370,12 @@ namespace ts {
         it("Convert empty option of libs to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": []
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: []
                     }
                 }, "tsconfig.json",
                 {
@@ -394,8 +394,8 @@ namespace ts {
         it("Convert incorrectly format tsconfig.json to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "modu": "commonjs",
+                    compilerOptions: {
+                        modu: "commonjs",
                     }
                 }, "tsconfig.json",
                 {
@@ -421,16 +421,34 @@ namespace ts {
             );
         });
 
+        it("Convert negative numbers in tsconfig.json ", () => {
+            assertCompilerOptions(
+                {
+                    compilerOptions: {
+                        allowJs: true,
+                        maxNodeModuleJsDepth: -1
+                    }
+                }, "tsconfig.json",
+                {
+                    compilerOptions: {
+                        allowJs: true,
+                        maxNodeModuleJsDepth: -1
+                    },
+                    errors: []
+                }
+            );
+        });
+
         // jsconfig.json
         it("Convert correctly format jsconfig.json to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "lib": ["es5", "es2015.core", "es2015.symbol"]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        lib: ["es5", "es2015.core", "es2015.symbol"]
                     }
                 }, "jsconfig.json",
                 {
@@ -453,13 +471,13 @@ namespace ts {
         it("Convert correctly format jsconfig.json with allowJs is false to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "module": "commonjs",
-                        "target": "es5",
-                        "noImplicitAny": false,
-                        "sourceMap": false,
-                        "allowJs": false,
-                        "lib": ["es5", "es2015.core", "es2015.symbol"]
+                    compilerOptions: {
+                        module: "commonjs",
+                        target: "es5",
+                        noImplicitAny: false,
+                        sourceMap: false,
+                        allowJs: false,
+                        lib: ["es5", "es2015.core", "es2015.symbol"]
                     }
                 }, "jsconfig.json",
                 {
@@ -482,8 +500,8 @@ namespace ts {
         it("Convert incorrectly format jsconfig.json to compiler-options ", () => {
             assertCompilerOptions(
                 {
-                    "compilerOptions": {
-                        "modu": "commonjs",
+                    compilerOptions: {
+                        modu: "commonjs",
                     }
                 }, "jsconfig.json",
                 {
diff --git a/src/harness/unittests/convertTypeAcquisitionFromJson.ts b/src/harness/unittests/convertTypeAcquisitionFromJson.ts
index 5a367edebbb..be1ada10a97 100644
--- a/src/harness/unittests/convertTypeAcquisitionFromJson.ts
+++ b/src/harness/unittests/convertTypeAcquisitionFromJson.ts
@@ -55,11 +55,11 @@ namespace ts {
         it("Convert deprecated typingOptions.enableAutoDiscovery format tsconfig.json to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typingOptions":
+                    typingOptions:
                     {
-                        "enableAutoDiscovery": true,
-                        "include": ["0.d.ts", "1.d.ts"],
-                        "exclude": ["0.js", "1.js"]
+                        enableAutoDiscovery: true,
+                        include: ["0.d.ts", "1.d.ts"],
+                        exclude: ["0.js", "1.js"]
                     }
                 },
                 "tsconfig.json",
@@ -77,11 +77,11 @@ namespace ts {
         it("Convert correctly format tsconfig.json to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enable": true,
-                        "include": ["0.d.ts", "1.d.ts"],
-                        "exclude": ["0.js", "1.js"]
+                        enable: true,
+                        include: ["0.d.ts", "1.d.ts"],
+                        exclude: ["0.js", "1.js"]
                     }
                 },
                 "tsconfig.json",
@@ -99,9 +99,9 @@ namespace ts {
         it("Convert incorrect format tsconfig.json to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enableAutoDiscovy": true,
+                        enableAutoDiscovy: true,
                     }
                 }, "tsconfig.json",
                 {
@@ -140,9 +140,9 @@ namespace ts {
         it("Convert tsconfig.json with only enable property to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enable": true
+                        enable: true
                     }
                 }, "tsconfig.json",
                 {
@@ -160,11 +160,11 @@ namespace ts {
         it("Convert jsconfig.json to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enable": false,
-                        "include": ["0.d.ts"],
-                        "exclude": ["0.js"]
+                        enable: false,
+                        include: ["0.d.ts"],
+                        exclude: ["0.js"]
                     }
                 }, "jsconfig.json",
                 {
@@ -194,9 +194,9 @@ namespace ts {
         it("Convert incorrect format jsconfig.json to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enableAutoDiscovy": true,
+                        enableAutoDiscovy: true,
                     }
                 }, "jsconfig.json",
                 {
@@ -222,9 +222,9 @@ namespace ts {
         it("Convert jsconfig.json with only enable property to typeAcquisition ", () => {
             assertTypeAcquisition(
                 {
-                    "typeAcquisition":
+                    typeAcquisition:
                     {
-                        "enable": false
+                        enable: false
                     }
                 }, "jsconfig.json",
                 {
diff --git a/src/harness/unittests/extractRanges.ts b/src/harness/unittests/extractRanges.ts
index e8e9a918f0d..493c9639c3d 100644
--- a/src/harness/unittests/extractRanges.ts
+++ b/src/harness/unittests/extractRanges.ts
@@ -191,7 +191,7 @@ function f() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalReturnStatement.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalReturnStatement.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed2",
@@ -210,7 +210,7 @@ function f() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed3",
@@ -229,7 +229,7 @@ function f() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed4",
@@ -248,7 +248,7 @@ function f() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed5",
@@ -269,7 +269,7 @@ function f2() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalReturnStatement.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalReturnStatement.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed6",
@@ -290,7 +290,7 @@ function f2() {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalReturnStatement.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalReturnStatement.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed7",
@@ -303,7 +303,7 @@ while (x) {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed8",
@@ -316,13 +316,13 @@ switch (x) {
 }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed9",
         `var x = ([#||]1 + 2);`,
         [
-            refactor.extractSymbol.Messages.CannotExtractEmpty.message
+            refactor.extractSymbol.Messages.cannotExtractEmpty.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed10",
@@ -333,7 +333,7 @@ switch (x) {
             }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRange.message
+            refactor.extractSymbol.Messages.cannotExtractRange.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed11",
@@ -350,21 +350,21 @@ switch (x) {
             }
         `,
         [
-            refactor.extractSymbol.Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements.message
+            refactor.extractSymbol.Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed12",
         `let [#|x|];`,
         [
-            refactor.extractSymbol.Messages.StatementOrExpressionExpected.message
+            refactor.extractSymbol.Messages.statementOrExpressionExpected.message
         ]);
 
         testExtractRangeFailed("extractRangeFailed13",
         `[#|return;|]`,
         [
-            refactor.extractSymbol.Messages.CannotExtractRange.message
+            refactor.extractSymbol.Messages.cannotExtractRange.message
         ]);
 
-        testExtractRangeFailed("extract-method-not-for-token-expression-statement", `[#|a|]`, [refactor.extractSymbol.Messages.CannotExtractIdentifier.message]);
+        testExtractRangeFailed("extract-method-not-for-token-expression-statement", `[#|a|]`, [refactor.extractSymbol.Messages.cannotExtractIdentifier.message]);
     });
 }
\ No newline at end of file
diff --git a/src/harness/unittests/extractTestHelpers.ts b/src/harness/unittests/extractTestHelpers.ts
index b8974694cfe..a04f443c3c9 100644
--- a/src/harness/unittests/extractTestHelpers.ts
+++ b/src/harness/unittests/extractTestHelpers.ts
@@ -67,33 +67,27 @@ namespace ts {
     }
 
     export const newLineCharacter = "\n";
-    export const getRuleProvider = memoize(getRuleProviderInternal);
-    function getRuleProviderInternal() {
-        const options = {
-            indentSize: 4,
-            tabSize: 4,
-            newLineCharacter,
-            convertTabsToSpaces: true,
-            indentStyle: ts.IndentStyle.Smart,
-            insertSpaceAfterConstructor: false,
-            insertSpaceAfterCommaDelimiter: true,
-            insertSpaceAfterSemicolonInForStatements: true,
-            insertSpaceBeforeAndAfterBinaryOperators: true,
-            insertSpaceAfterKeywordsInControlFlowStatements: true,
-            insertSpaceAfterFunctionKeywordForAnonymousFunctions: false,
-            insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis: false,
-            insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets: false,
-            insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces: true,
-            insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: false,
-            insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces: false,
-            insertSpaceBeforeFunctionParenthesis: false,
-            placeOpenBraceOnNewLineForFunctions: false,
-            placeOpenBraceOnNewLineForControlBlocks: false,
-        };
-        const rulesProvider = new formatting.RulesProvider();
-        rulesProvider.ensureUpToDate(options);
-        return rulesProvider;
-    }
+    export const testFormatOptions: ts.FormatCodeSettings = {
+        indentSize: 4,
+        tabSize: 4,
+        newLineCharacter,
+        convertTabsToSpaces: true,
+        indentStyle: ts.IndentStyle.Smart,
+        insertSpaceAfterConstructor: false,
+        insertSpaceAfterCommaDelimiter: true,
+        insertSpaceAfterSemicolonInForStatements: true,
+        insertSpaceBeforeAndAfterBinaryOperators: true,
+        insertSpaceAfterKeywordsInControlFlowStatements: true,
+        insertSpaceAfterFunctionKeywordForAnonymousFunctions: false,
+        insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis: false,
+        insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets: false,
+        insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces: true,
+        insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: false,
+        insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces: false,
+        insertSpaceBeforeFunctionParenthesis: false,
+        placeOpenBraceOnNewLineForFunctions: false,
+        placeOpenBraceOnNewLineForControlBlocks: false,
+    };
 
     const notImplementedHost: LanguageServiceHost = {
         getCompilationSettings: notImplemented,
@@ -126,14 +120,14 @@ namespace ts {
 
             const sourceFile = program.getSourceFile(path);
             const context: RefactorContext = {
-                cancellationToken: { throwIfCancellationRequested() { }, isCancellationRequested() { return false; } },
+                cancellationToken: { throwIfCancellationRequested: noop, isCancellationRequested: returnFalse },
                 newLineCharacter,
                 program,
                 file: sourceFile,
                 startPosition: selectionRange.start,
                 endPosition: selectionRange.end,
                 host: notImplementedHost,
-                rulesProvider: getRuleProvider()
+                formatContext: formatting.getFormatContext(testFormatOptions),
             };
             const rangeToExtract = refactor.extractSymbol.getRangeToExtract(sourceFile, createTextSpanFromBounds(selectionRange.start, selectionRange.end));
             assert.equal(rangeToExtract.errors, undefined, rangeToExtract.errors && "Range error: " + rangeToExtract.errors[0].messageText);
@@ -190,14 +184,14 @@ namespace ts {
             const program = projectService.inferredProjects[0].getLanguageService().getProgram();
             const sourceFile = program.getSourceFile(f.path);
             const context: RefactorContext = {
-                cancellationToken: { throwIfCancellationRequested() { }, isCancellationRequested() { return false; } },
+                cancellationToken: { throwIfCancellationRequested: noop, isCancellationRequested: returnFalse },
                 newLineCharacter,
                 program,
                 file: sourceFile,
                 startPosition: selectionRange.start,
                 endPosition: selectionRange.end,
                 host: notImplementedHost,
-                rulesProvider: getRuleProvider()
+                formatContext: formatting.getFormatContext(testFormatOptions),
             };
             const rangeToExtract = refactor.extractSymbol.getRangeToExtract(sourceFile, createTextSpanFromBounds(selectionRange.start, selectionRange.end));
             assert.isUndefined(rangeToExtract.errors, rangeToExtract.errors && "Range error: " + rangeToExtract.errors[0].messageText);
diff --git a/src/harness/unittests/hostNewLineSupport.ts b/src/harness/unittests/hostNewLineSupport.ts
index 9f6b09dfb72..95a05f101f7 100644
--- a/src/harness/unittests/hostNewLineSupport.ts
+++ b/src/harness/unittests/hostNewLineSupport.ts
@@ -5,10 +5,10 @@ namespace ts {
             function snapFor(path: string): IScriptSnapshot {
                 if (path === "lib.d.ts") {
                     return {
-                        dispose() {},
+                        dispose: noop,
                         getChangeRange() { return undefined; },
                         getLength() { return 0; },
-                        getText(_start, _end) {
+                        getText() {
                             return "";
                         }
                     };
@@ -16,7 +16,7 @@ namespace ts {
                 const result = forEach(files, f => f.unitName === path ? f : undefined);
                 if (result) {
                     return {
-                        dispose() {},
+                        dispose: noop,
                         getChangeRange() { return undefined; },
                         getLength() { return result.content.length; },
                         getText(start, end) {
diff --git a/src/harness/unittests/incrementalParser.ts b/src/harness/unittests/incrementalParser.ts
index fbd8a60da92..c71b89d3da6 100644
--- a/src/harness/unittests/incrementalParser.ts
+++ b/src/harness/unittests/incrementalParser.ts
@@ -591,7 +591,7 @@ module m3 { }\
             const index = 0;
             const newTextAndChange = withInsert(oldText, index, "declare ");
 
-            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 3);
+            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 0);
         });
 
         it("Insert function above arrow function with comment", () => {
@@ -674,7 +674,7 @@ module m3 { }\
             const oldText = ScriptSnapshot.fromString(source);
             const newTextAndChange = withInsert(oldText, 0, "{");
 
-            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 9);
+            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 4);
         });
 
         it("Removing block around function declarations", () => {
@@ -683,7 +683,7 @@ module m3 { }\
             const oldText = ScriptSnapshot.fromString(source);
             const newTextAndChange = withDelete(oldText, 0, "{".length);
 
-            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 9);
+            compareTrees(oldText, newTextAndChange.text, newTextAndChange.textChangeRange, 4);
         });
 
         it("Moving methods from class to object literal", () => {
diff --git a/src/harness/unittests/languageService.ts b/src/harness/unittests/languageService.ts
index fd0a95c167f..1407a518617 100644
--- a/src/harness/unittests/languageService.ts
+++ b/src/harness/unittests/languageService.ts
@@ -45,7 +45,7 @@ export function Component(x: Config): any;`
                 readDirectory: noop as any,
             });
             const definitions = languageService.getDefinitionAtPosition("foo.ts", 160); // 160 is the latter `vueTemplateHtml` position
-            expect(definitions).to.exist;
+            expect(definitions).to.exist; // tslint:disable-line no-unused-expression
         });
     });
 }
\ No newline at end of file
diff --git a/src/harness/unittests/moduleResolution.ts b/src/harness/unittests/moduleResolution.ts
index 32301d6dccf..de79ba06cf9 100644
--- a/src/harness/unittests/moduleResolution.ts
+++ b/src/harness/unittests/moduleResolution.ts
@@ -127,7 +127,7 @@ namespace ts {
 
             function test(hasDirectoryExists: boolean) {
                 const containingFile = { name: containingFileName };
-                const packageJson = { name: packageJsonFileName, content: JSON.stringify({ "typings": fieldRef }) };
+                const packageJson = { name: packageJsonFileName, content: JSON.stringify({ typings: fieldRef }) };
                 const moduleFile = { name: moduleFileName };
                 const resolution = nodeModuleNameResolver(moduleName, containingFile.name, {}, createModuleResolutionHost(hasDirectoryExists, containingFile, packageJson, moduleFile));
                 checkResolvedModule(resolution.resolvedModule, createResolvedModule(moduleFile.name));
@@ -149,7 +149,7 @@ namespace ts {
 
             function test(hasDirectoryExists: boolean) {
                 const containingFile = { name: "/a/b.ts" };
-                const packageJson = { name: "/node_modules/b/package.json", content: JSON.stringify({ "typings": typings }) };
+                const packageJson = { name: "/node_modules/b/package.json", content: JSON.stringify({ typings }) };
                 const moduleFile = { name: "/a/b.d.ts" };
 
                 const indexPath = "/node_modules/b/index.d.ts";
@@ -163,7 +163,7 @@ namespace ts {
 
         it("module name as directory - handle invalid 'typings'", () => {
             testTypingsIgnored(["a", "b"]);
-            testTypingsIgnored({ "a": "b" });
+            testTypingsIgnored({ a: "b" });
             testTypingsIgnored(/*typings*/ true);
             testTypingsIgnored(/*typings*/ null); // tslint:disable-line no-null-keyword
             testTypingsIgnored(/*typings*/ undefined);
@@ -803,7 +803,7 @@ import b = require("./moduleB");
 
             function test(hasDirectoryExists: boolean) {
                 const file1: File = { name: "/root/folder1/file1.ts" };
-                const file1_1: File = { name: "/root/folder1/file1_1/index.d.ts" };
+                const file1_1: File = { name: "/root/folder1/file1_1/index.d.ts" }; // tslint:disable-line variable-name
                 const file2: File = { name: "/root/generated/folder1/file2.ts" };
                 const file3: File = { name: "/root/generated/folder2/file3.ts" };
                 const host = createModuleResolutionHost(hasDirectoryExists, file1, file1_1, file2, file3);
diff --git a/src/harness/unittests/printer.ts b/src/harness/unittests/printer.ts
index 4aaddce5c00..ad60484d963 100644
--- a/src/harness/unittests/printer.ts
+++ b/src/harness/unittests/printer.ts
@@ -55,6 +55,7 @@ namespace ts {
             printsCorrectly("removeComments", { removeComments: true }, printer => printer.printFile(sourceFile));
 
             // github #14948
+            // tslint:disable-next-line no-invalid-template-strings
             printsCorrectly("templateLiteral", {}, printer => printer.printFile(createSourceFile("source.ts", "let greeting = `Hi ${name}, how are you?`;", ScriptTarget.ES2017)));
 
             // github #18071
diff --git a/src/harness/unittests/reuseProgramStructure.ts b/src/harness/unittests/reuseProgramStructure.ts
index e0c0e6f80a8..fdccc8a7795 100644
--- a/src/harness/unittests/reuseProgramStructure.ts
+++ b/src/harness/unittests/reuseProgramStructure.ts
@@ -243,111 +243,111 @@ namespace ts {
         ];
 
         it("successful if change does not affect imports", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target });
-            const program_2 = updateProgram(program_1, ["a.ts"], { target }, files => {
+            const program1 = newProgram(files, ["a.ts"], { target });
+            const program2 = updateProgram(program1, ["a.ts"], { target }, files => {
                 files[0].text = files[0].text.updateProgram("var x = 100");
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
-            const program1Diagnostics = program_1.getSemanticDiagnostics(program_1.getSourceFile("a.ts"));
-            const program2Diagnostics = program_2.getSemanticDiagnostics(program_1.getSourceFile("a.ts"));
+            assert.equal(program1.structureIsReused, StructureIsReused.Completely);
+            const program1Diagnostics = program1.getSemanticDiagnostics(program1.getSourceFile("a.ts"));
+            const program2Diagnostics = program2.getSemanticDiagnostics(program1.getSourceFile("a.ts"));
             assert.equal(program1Diagnostics.length, program2Diagnostics.length);
         });
 
         it("successful if change does not affect type reference directives", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target });
-            const program_2 = updateProgram(program_1, ["a.ts"], { target }, files => {
+            const program1 = newProgram(files, ["a.ts"], { target });
+            const program2 = updateProgram(program1, ["a.ts"], { target }, files => {
                 files[0].text = files[0].text.updateProgram("var x = 100");
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
-            const program1Diagnostics = program_1.getSemanticDiagnostics(program_1.getSourceFile("a.ts"));
-            const program2Diagnostics = program_2.getSemanticDiagnostics(program_1.getSourceFile("a.ts"));
+            assert.equal(program1.structureIsReused, StructureIsReused.Completely);
+            const program1Diagnostics = program1.getSemanticDiagnostics(program1.getSourceFile("a.ts"));
+            const program2Diagnostics = program2.getSemanticDiagnostics(program1.getSourceFile("a.ts"));
             assert.equal(program1Diagnostics.length, program2Diagnostics.length);
         });
 
         it("fails if change affects tripleslash references", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target });
-            updateProgram(program_1, ["a.ts"], { target }, files => {
+            const program1 = newProgram(files, ["a.ts"], { target });
+            updateProgram(program1, ["a.ts"], { target }, files => {
                 const newReferences = `/// <reference path='b.ts'/>
                 /// <reference path='c.ts'/>
                 `;
                 files[0].text = files[0].text.updateReferences(newReferences);
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.SafeModules);
+            assert.equal(program1.structureIsReused, StructureIsReused.SafeModules);
         });
 
         it("fails if change affects type references", () => {
-            const program_1 = newProgram(files, ["a.ts"], { types: ["a"] });
-            updateProgram(program_1, ["a.ts"], { types: ["b"] }, noop);
-            assert.equal(program_1.structureIsReused, StructureIsReused.Not);
+            const program1 = newProgram(files, ["a.ts"], { types: ["a"] });
+            updateProgram(program1, ["a.ts"], { types: ["b"] }, noop);
+            assert.equal(program1.structureIsReused, StructureIsReused.Not);
         });
 
         it("succeeds if change doesn't affect type references", () => {
-            const program_1 = newProgram(files, ["a.ts"], { types: ["a"] });
-            updateProgram(program_1, ["a.ts"], { types: ["a"] }, noop);
-            assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
+            const program1 = newProgram(files, ["a.ts"], { types: ["a"] });
+            updateProgram(program1, ["a.ts"], { types: ["a"] }, noop);
+            assert.equal(program1.structureIsReused, StructureIsReused.Completely);
         });
 
         it("fails if change affects imports", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target });
-            updateProgram(program_1, ["a.ts"], { target }, files => {
+            const program1 = newProgram(files, ["a.ts"], { target });
+            updateProgram(program1, ["a.ts"], { target }, files => {
                 files[2].text = files[2].text.updateImportsAndExports("import x from 'b'");
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.SafeModules);
+            assert.equal(program1.structureIsReused, StructureIsReused.SafeModules);
         });
 
         it("fails if change affects type directives", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target });
-            updateProgram(program_1, ["a.ts"], { target }, files => {
+            const program1 = newProgram(files, ["a.ts"], { target });
+            updateProgram(program1, ["a.ts"], { target }, files => {
                 const newReferences = `
 /// <reference path='b.ts'/>
 /// <reference path='non-existing-file.ts'/>
 /// <reference types="typerefs1" />`;
                 files[0].text = files[0].text.updateReferences(newReferences);
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.SafeModules);
+            assert.equal(program1.structureIsReused, StructureIsReused.SafeModules);
         });
 
         it("fails if module kind changes", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS });
-            updateProgram(program_1, ["a.ts"], { target, module: ModuleKind.AMD }, noop);
-            assert.equal(program_1.structureIsReused, StructureIsReused.Not);
+            const program1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS });
+            updateProgram(program1, ["a.ts"], { target, module: ModuleKind.AMD }, noop);
+            assert.equal(program1.structureIsReused, StructureIsReused.Not);
         });
 
         it("fails if rootdir changes", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS, rootDir: "/a/b" });
-            updateProgram(program_1, ["a.ts"], { target, module: ModuleKind.CommonJS, rootDir: "/a/c" }, noop);
-            assert.equal(program_1.structureIsReused, StructureIsReused.Not);
+            const program1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS, rootDir: "/a/b" });
+            updateProgram(program1, ["a.ts"], { target, module: ModuleKind.CommonJS, rootDir: "/a/c" }, noop);
+            assert.equal(program1.structureIsReused, StructureIsReused.Not);
         });
 
         it("fails if config path changes", () => {
-            const program_1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS, configFilePath: "/a/b/tsconfig.json" });
-            updateProgram(program_1, ["a.ts"], { target, module: ModuleKind.CommonJS, configFilePath: "/a/c/tsconfig.json" }, noop);
-            assert.equal(program_1.structureIsReused, StructureIsReused.Not);
+            const program1 = newProgram(files, ["a.ts"], { target, module: ModuleKind.CommonJS, configFilePath: "/a/b/tsconfig.json" });
+            updateProgram(program1, ["a.ts"], { target, module: ModuleKind.CommonJS, configFilePath: "/a/c/tsconfig.json" }, noop);
+            assert.equal(program1.structureIsReused, StructureIsReused.Not);
         });
 
         it("succeeds if missing files remain missing", () => {
             const options: CompilerOptions = { target, noLib: true };
 
-            const program_1 = newProgram(files, ["a.ts"], options);
-            assert.notDeepEqual(emptyArray, program_1.getMissingFilePaths());
+            const program1 = newProgram(files, ["a.ts"], options);
+            assert.notDeepEqual(emptyArray, program1.getMissingFilePaths());
 
-            const program_2 = updateProgram(program_1, ["a.ts"], options, noop);
-            assert.deepEqual(program_1.getMissingFilePaths(), program_2.getMissingFilePaths());
+            const program2 = updateProgram(program1, ["a.ts"], options, noop);
+            assert.deepEqual(program1.getMissingFilePaths(), program2.getMissingFilePaths());
 
-            assert.equal(StructureIsReused.Completely, program_1.structureIsReused);
+            assert.equal(StructureIsReused.Completely, program1.structureIsReused);
         });
 
         it("fails if missing file is created", () => {
             const options: CompilerOptions = { target, noLib: true };
 
-            const program_1 = newProgram(files, ["a.ts"], options);
-            assert.notDeepEqual(emptyArray, program_1.getMissingFilePaths());
+            const program1 = newProgram(files, ["a.ts"], options);
+            assert.notDeepEqual(emptyArray, program1.getMissingFilePaths());
 
             const newTexts: NamedSourceText[] = files.concat([{ name: "non-existing-file.ts", text: SourceText.New("", "", `var x = 1`) }]);
-            const program_2 = updateProgram(program_1, ["a.ts"], options, noop, newTexts);
-            assert.deepEqual(emptyArray, program_2.getMissingFilePaths());
+            const program2 = updateProgram(program1, ["a.ts"], options, noop, newTexts);
+            assert.deepEqual(emptyArray, program2.getMissingFilePaths());
 
-            assert.equal(StructureIsReused.Not, program_1.structureIsReused);
+            assert.equal(StructureIsReused.Not, program1.structureIsReused);
         });
 
         it("resolution cache follows imports", () => {
@@ -359,34 +359,34 @@ namespace ts {
             ];
             const options: CompilerOptions = { target };
 
-            const program_1 = newProgram(files, ["a.ts"], options);
-            checkResolvedModulesCache(program_1, "a.ts", createMapFromTemplate({ "b": createResolvedModule("b.ts") }));
-            checkResolvedModulesCache(program_1, "b.ts", /*expectedContent*/ undefined);
+            const program1 = newProgram(files, ["a.ts"], options);
+            checkResolvedModulesCache(program1, "a.ts", createMapFromTemplate({ b: createResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program1, "b.ts", /*expectedContent*/ undefined);
 
-            const program_2 = updateProgram(program_1, ["a.ts"], options, files => {
+            const program2 = updateProgram(program1, ["a.ts"], options, files => {
                 files[0].text = files[0].text.updateProgram("var x = 2");
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
+            assert.equal(program1.structureIsReused, StructureIsReused.Completely);
 
             // content of resolution cache should not change
-            checkResolvedModulesCache(program_1, "a.ts", createMapFromTemplate({ "b": createResolvedModule("b.ts") }));
-            checkResolvedModulesCache(program_1, "b.ts", /*expectedContent*/ undefined);
+            checkResolvedModulesCache(program1, "a.ts", createMapFromTemplate({ b: createResolvedModule("b.ts") }));
+            checkResolvedModulesCache(program1, "b.ts", /*expectedContent*/ undefined);
 
             // imports has changed - program is not reused
-            const program_3 = updateProgram(program_2, ["a.ts"], options, files => {
+            const program3 = updateProgram(program2, ["a.ts"], options, files => {
                 files[0].text = files[0].text.updateImportsAndExports("");
             });
-            assert.equal(program_2.structureIsReused, StructureIsReused.SafeModules);
-            checkResolvedModulesCache(program_3, "a.ts", /*expectedContent*/ undefined);
+            assert.equal(program2.structureIsReused, StructureIsReused.SafeModules);
+            checkResolvedModulesCache(program3, "a.ts", /*expectedContent*/ undefined);
 
-            const program_4 = updateProgram(program_3, ["a.ts"], options, files => {
+            const program4 = updateProgram(program3, ["a.ts"], options, files => {
                 const newImports = `import x from 'b'
                 import y from 'c'
                 `;
                 files[0].text = files[0].text.updateImportsAndExports(newImports);
             });
-            assert.equal(program_3.structureIsReused, StructureIsReused.SafeModules);
-            checkResolvedModulesCache(program_4, "a.ts", createMapFromTemplate({ "b": createResolvedModule("b.ts"), "c": undefined }));
+            assert.equal(program3.structureIsReused, StructureIsReused.SafeModules);
+            checkResolvedModulesCache(program4, "a.ts", createMapFromTemplate({ b: createResolvedModule("b.ts"), c: undefined }));
         });
 
         it("resolved type directives cache follows type directives", () => {
@@ -396,35 +396,35 @@ namespace ts {
             ];
             const options: CompilerOptions = { target, typeRoots: ["/types"] };
 
-            const program_1 = newProgram(files, ["/a.ts"], options);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMapFromTemplate({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
-            checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", /*expectedContent*/ undefined);
+            const program1 = newProgram(files, ["/a.ts"], options);
+            checkResolvedTypeDirectivesCache(program1, "/a.ts", createMapFromTemplate({ typedefs: { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program1, "/types/typedefs/index.d.ts", /*expectedContent*/ undefined);
 
-            const program_2 = updateProgram(program_1, ["/a.ts"], options, files => {
+            const program2 = updateProgram(program1, ["/a.ts"], options, files => {
                 files[0].text = files[0].text.updateProgram("var x = 2");
             });
-            assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
+            assert.equal(program1.structureIsReused, StructureIsReused.Completely);
 
             // content of resolution cache should not change
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMapFromTemplate({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
-            checkResolvedTypeDirectivesCache(program_1, "/types/typedefs/index.d.ts", /*expectedContent*/ undefined);
+            checkResolvedTypeDirectivesCache(program1, "/a.ts", createMapFromTemplate({ typedefs: { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            checkResolvedTypeDirectivesCache(program1, "/types/typedefs/index.d.ts", /*expectedContent*/ undefined);
 
             // type reference directives has changed - program is not reused
-            const program_3 = updateProgram(program_2, ["/a.ts"], options, files => {
+            const program3 = updateProgram(program2, ["/a.ts"], options, files => {
                 files[0].text = files[0].text.updateReferences("");
             });
 
-            assert.equal(program_2.structureIsReused, StructureIsReused.SafeModules);
-            checkResolvedTypeDirectivesCache(program_3, "/a.ts", /*expectedContent*/ undefined);
+            assert.equal(program2.structureIsReused, StructureIsReused.SafeModules);
+            checkResolvedTypeDirectivesCache(program3, "/a.ts", /*expectedContent*/ undefined);
 
-            updateProgram(program_3, ["/a.ts"], options, files => {
+            updateProgram(program3, ["/a.ts"], options, files => {
                 const newReferences = `/// <reference types="typedefs"/>
                 /// <reference types="typedefs2"/>
                 `;
                 files[0].text = files[0].text.updateReferences(newReferences);
             });
-            assert.equal(program_3.structureIsReused, StructureIsReused.SafeModules);
-            checkResolvedTypeDirectivesCache(program_1, "/a.ts", createMapFromTemplate({ "typedefs": { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
+            assert.equal(program3.structureIsReused, StructureIsReused.SafeModules);
+            checkResolvedTypeDirectivesCache(program1, "/a.ts", createMapFromTemplate({ typedefs: { resolvedFileName: "/types/typedefs/index.d.ts", primary: true } }));
         });
 
         it("fetches imports after npm install", () => {
@@ -529,18 +529,18 @@ namespace ts {
                     "======== Module name 'fs' was not resolved. ========",
                 ], "should look for 'fs'");
 
-            const program_2 = updateProgram(program, program.getRootFileNames(), options, f => {
+            const program2 = updateProgram(program, program.getRootFileNames(), options, f => {
                 f[0].text = f[0].text.updateProgram("var x = 1;");
             });
-            assert.deepEqual(program_2.host.getTrace(), [
+            assert.deepEqual(program2.host.getTrace(), [
                 "Module 'fs' was resolved as ambient module declared in '/a/b/node.d.ts' since this file was not modified."
             ], "should reuse 'fs' since node.d.ts was not changed");
 
-            const program_3 = updateProgram(program_2, program_2.getRootFileNames(), options, f => {
+            const program3 = updateProgram(program2, program2.getRootFileNames(), options, f => {
                 f[0].text = f[0].text.updateProgram("var y = 1;");
                 f[1].text = f[1].text.updateProgram("declare var process: any");
             });
-            assert.deepEqual(program_3.host.getTrace(),
+            assert.deepEqual(program3.host.getTrace(),
                 [
                     "======== Resolving module 'fs' from '/a/b/app.ts'. ========",
                     "Module resolution kind is not specified, using 'Classic'.",
@@ -598,10 +598,10 @@ namespace ts {
             ];
 
             const options: CompilerOptions = { target: ScriptTarget.ES2015, traceResolution: true, moduleResolution: ModuleResolutionKind.Classic };
-            const program_1 = newProgram(files, files.map(f => f.name), options);
+            const program1 = newProgram(files, files.map(f => f.name), options);
             let expectedErrors = 0;
             {
-                assert.deepEqual(program_1.host.getTrace(),
+                assert.deepEqual(program1.host.getTrace(),
                     [
                         "======== Resolving type reference directive 'typerefs1', containing file 'f1.ts', root directory 'node_modules/@types'. ========",
                         "Resolving with primary search path 'node_modules/@types'.",
@@ -626,22 +626,22 @@ namespace ts {
                         "File 'f1.ts' exist - use it as a name resolution result.",
                         "======== Module name './f1' was successfully resolved to 'f1.ts'. ========"
                     ],
-                    "program_1: execute module resolution normally.");
+                    "program1: execute module resolution normally.");
 
-                const program_1Diagnostics = program_1.getSemanticDiagnostics(program_1.getSourceFile("f2.ts"));
-                assert.lengthOf(program_1Diagnostics, expectedErrors, `initial program should be well-formed`);
+                const program1Diagnostics = program1.getSemanticDiagnostics(program1.getSourceFile("f2.ts"));
+                assert.lengthOf(program1Diagnostics, expectedErrors, `initial program should be well-formed`);
             }
             const indexOfF1 = 6;
-            const program_2 = updateProgram(program_1, program_1.getRootFileNames(), options, f => {
+            const program2 = updateProgram(program1, program1.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateReferences(`/// <reference path="a1.ts"/>${newLine}/// <reference types="typerefs1"/>`);
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_2Diagnostics = program_2.getSemanticDiagnostics(program_2.getSourceFile("f2.ts"));
-                assert.lengthOf(program_2Diagnostics, expectedErrors, `removing no-default-lib shouldn't affect any types used.`);
+                const program2Diagnostics = program2.getSemanticDiagnostics(program2.getSourceFile("f2.ts"));
+                assert.lengthOf(program2Diagnostics, expectedErrors, `removing no-default-lib shouldn't affect any types used.`);
 
-                assert.deepEqual(program_2.host.getTrace(), [
+                assert.deepEqual(program2.host.getTrace(), [
                     "======== Resolving type reference directive 'typerefs1', containing file 'f1.ts', root directory 'node_modules/@types'. ========",
                     "Resolving with primary search path 'node_modules/@types'.",
                     "File 'node_modules/@types/typerefs1/package.json' does not exist.",
@@ -658,19 +658,19 @@ namespace ts {
                     "======== Type reference directive 'typerefs2' was successfully resolved to 'node_modules/@types/typerefs2/index.d.ts', primary: true. ========",
                     "Reusing resolution of module './b2' to file 'f2.ts' from old program.",
                     "Reusing resolution of module './f1' to file 'f2.ts' from old program."
-                ], "program_2: reuse module resolutions in f2 since it is unchanged");
+                ], "program2: reuse module resolutions in f2 since it is unchanged");
             }
 
-            const program_3 = updateProgram(program_2, program_2.getRootFileNames(), options, f => {
+            const program3 = updateProgram(program2, program2.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateReferences(`/// <reference path="a1.ts"/>`);
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_3Diagnostics = program_3.getSemanticDiagnostics(program_3.getSourceFile("f2.ts"));
-                assert.lengthOf(program_3Diagnostics, expectedErrors, `typerefs2 was unused, so diagnostics should be unaffected.`);
+                const program3Diagnostics = program3.getSemanticDiagnostics(program3.getSourceFile("f2.ts"));
+                assert.lengthOf(program3Diagnostics, expectedErrors, `typerefs2 was unused, so diagnostics should be unaffected.`);
 
-                assert.deepEqual(program_3.host.getTrace(), [
+                assert.deepEqual(program3.host.getTrace(), [
                     "======== Resolving module './b1' from 'f1.ts'. ========",
                     "Explicitly specified module resolution kind: 'Classic'.",
                     "File 'b1.ts' exist - use it as a name resolution result.",
@@ -682,20 +682,20 @@ namespace ts {
                     "======== Type reference directive 'typerefs2' was successfully resolved to 'node_modules/@types/typerefs2/index.d.ts', primary: true. ========",
                     "Reusing resolution of module './b2' to file 'f2.ts' from old program.",
                     "Reusing resolution of module './f1' to file 'f2.ts' from old program."
-                ], "program_3: reuse module resolutions in f2 since it is unchanged");
+                ], "program3: reuse module resolutions in f2 since it is unchanged");
             }
 
 
-            const program_4 = updateProgram(program_3, program_3.getRootFileNames(), options, f => {
+            const program4 = updateProgram(program3, program3.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateReferences("");
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_4Diagnostics = program_4.getSemanticDiagnostics(program_4.getSourceFile("f2.ts"));
-                assert.lengthOf(program_4Diagnostics, expectedErrors, `a1.ts was unused, so diagnostics should be unaffected.`);
+                const program4Diagnostics = program4.getSemanticDiagnostics(program4.getSourceFile("f2.ts"));
+                assert.lengthOf(program4Diagnostics, expectedErrors, `a1.ts was unused, so diagnostics should be unaffected.`);
 
-                assert.deepEqual(program_4.host.getTrace(), [
+                assert.deepEqual(program4.host.getTrace(), [
                     "======== Resolving module './b1' from 'f1.ts'. ========",
                     "Explicitly specified module resolution kind: 'Classic'.",
                     "File 'b1.ts' exist - use it as a name resolution result.",
@@ -710,16 +710,16 @@ namespace ts {
                 ], "program_4: reuse module resolutions in f2 since it is unchanged");
             }
 
-            const program_5 = updateProgram(program_4, program_4.getRootFileNames(), options, f => {
+            const program5 = updateProgram(program4, program4.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateImportsAndExports(`import { B } from './b1';`);
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_5Diagnostics = program_5.getSemanticDiagnostics(program_5.getSourceFile("f2.ts"));
-                assert.lengthOf(program_5Diagnostics, ++expectedErrors, `import of BB in f1 fails. BB is of type any. Add one error`);
+                const program5Diagnostics = program5.getSemanticDiagnostics(program5.getSourceFile("f2.ts"));
+                assert.lengthOf(program5Diagnostics, ++expectedErrors, `import of BB in f1 fails. BB is of type any. Add one error`);
 
-                assert.deepEqual(program_5.host.getTrace(), [
+                assert.deepEqual(program5.host.getTrace(), [
                     "======== Resolving module './b1' from 'f1.ts'. ========",
                     "Explicitly specified module resolution kind: 'Classic'.",
                     "File 'b1.ts' exist - use it as a name resolution result.",
@@ -727,16 +727,16 @@ namespace ts {
                 ], "program_5: exports do not affect program structure, so f2's resolutions are silently reused.");
             }
 
-            const program_6 = updateProgram(program_5, program_5.getRootFileNames(), options, f => {
+            const program6 = updateProgram(program5, program5.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateProgram("");
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_6Diagnostics = program_6.getSemanticDiagnostics(program_6.getSourceFile("f2.ts"));
-                assert.lengthOf(program_6Diagnostics, expectedErrors, `import of BB in f1 fails.`);
+                const program6Diagnostics = program6.getSemanticDiagnostics(program6.getSourceFile("f2.ts"));
+                assert.lengthOf(program6Diagnostics, expectedErrors, `import of BB in f1 fails.`);
 
-                assert.deepEqual(program_6.host.getTrace(), [
+                assert.deepEqual(program6.host.getTrace(), [
                     "======== Resolving module './b1' from 'f1.ts'. ========",
                     "Explicitly specified module resolution kind: 'Classic'.",
                     "File 'b1.ts' exist - use it as a name resolution result.",
@@ -751,16 +751,16 @@ namespace ts {
                 ], "program_6: reuse module resolutions in f2 since it is unchanged");
             }
 
-            const program_7 = updateProgram(program_6, program_6.getRootFileNames(), options, f => {
+            const program7 = updateProgram(program6, program6.getRootFileNames(), options, f => {
                 const newSourceText = f[indexOfF1].text.updateImportsAndExports("");
                 f[indexOfF1] = { name: "f1.ts", text: newSourceText };
             });
 
             {
-                const program_7Diagnostics = program_7.getSemanticDiagnostics(program_7.getSourceFile("f2.ts"));
-                assert.lengthOf(program_7Diagnostics, expectedErrors, `removing import is noop with respect to program, so no change in diagnostics.`);
+                const program7Diagnostics = program7.getSemanticDiagnostics(program7.getSourceFile("f2.ts"));
+                assert.lengthOf(program7Diagnostics, expectedErrors, `removing import is noop with respect to program, so no change in diagnostics.`);
 
-                assert.deepEqual(program_7.host.getTrace(), [
+                assert.deepEqual(program7.host.getTrace(), [
                     "======== Resolving type reference directive 'typerefs2', containing file 'f2.ts', root directory 'node_modules/@types'. ========",
                     "Resolving with primary search path 'node_modules/@types'.",
                     "File 'node_modules/@types/typerefs2/package.json' does not exist.",
@@ -820,47 +820,47 @@ namespace ts {
             }
 
             it("No changes -> redirect not broken", () => {
-                const program_1 = createRedirectProgram();
+                const program1 = createRedirectProgram();
 
-                const program_2 = updateRedirectProgram(program_1, files => {
+                const program2 = updateRedirectProgram(program1, files => {
                     updateProgramText(files, root, "const x = 1;");
                 });
-                assert.equal(program_1.structureIsReused, StructureIsReused.Completely);
-                assert.deepEqual(program_2.getSemanticDiagnostics(), emptyArray);
+                assert.equal(program1.structureIsReused, StructureIsReused.Completely);
+                assert.deepEqual(program2.getSemanticDiagnostics(), emptyArray);
             });
 
             it("Target changes -> redirect broken", () => {
-                const program_1 = createRedirectProgram();
-                assert.deepEqual(program_1.getSemanticDiagnostics(), emptyArray);
+                const program1 = createRedirectProgram();
+                assert.deepEqual(program1.getSemanticDiagnostics(), emptyArray);
 
-                const program_2 = updateRedirectProgram(program_1, files => {
+                const program2 = updateRedirectProgram(program1, files => {
                     updateProgramText(files, axIndex, "export default class X { private x: number; private y: number; }");
                     updateProgramText(files, axPackage, JSON.stringify('{ name: "x", version: "1.2.4" }'));
                 });
-                assert.equal(program_1.structureIsReused, StructureIsReused.Not);
-                assert.lengthOf(program_2.getSemanticDiagnostics(), 1);
+                assert.equal(program1.structureIsReused, StructureIsReused.Not);
+                assert.lengthOf(program2.getSemanticDiagnostics(), 1);
             });
 
             it("Underlying changes -> redirect broken", () => {
-                const program_1 = createRedirectProgram();
+                const program1 = createRedirectProgram();
 
-                const program_2 = updateRedirectProgram(program_1, files => {
+                const program2 = updateRedirectProgram(program1, files => {
                     updateProgramText(files, bxIndex, "export default class X { private x: number; private y: number; }");
                     updateProgramText(files, bxPackage, JSON.stringify({ name: "x", version: "1.2.4" }));
                 });
-                assert.equal(program_1.structureIsReused, StructureIsReused.Not);
-                assert.lengthOf(program_2.getSemanticDiagnostics(), 1);
+                assert.equal(program1.structureIsReused, StructureIsReused.Not);
+                assert.lengthOf(program2.getSemanticDiagnostics(), 1);
             });
 
             it("Previously duplicate packages -> program structure not reused", () => {
-                const program_1 = createRedirectProgram({ bVersion: "1.2.4", bText: "export = class X { private x: number; }" });
+                const program1 = createRedirectProgram({ bVersion: "1.2.4", bText: "export = class X { private x: number; }" });
 
-                const program_2 = updateRedirectProgram(program_1, files => {
+                const program2 = updateRedirectProgram(program1, files => {
                     updateProgramText(files, bxIndex, "export default class X { private x: number; }");
                     updateProgramText(files, bxPackage, JSON.stringify({ name: "x", version: "1.2.3" }));
                 });
-                assert.equal(program_1.structureIsReused, StructureIsReused.Not);
-                assert.deepEqual(program_2.getSemanticDiagnostics(), []);
+                assert.equal(program1.structureIsReused, StructureIsReused.Not);
+                assert.deepEqual(program2.getSemanticDiagnostics(), []);
             });
         });
     });
diff --git a/src/harness/unittests/services/colorization.ts b/src/harness/unittests/services/colorization.ts
index eb2606bb08e..17d4132e9e5 100644
--- a/src/harness/unittests/services/colorization.ts
+++ b/src/harness/unittests/services/colorization.ts
@@ -1,12 +1,14 @@
 /// <reference path="..\..\harnessLanguageService.ts" />
 
+// tslint:disable no-invalid-template-strings (lots of tests use quoted code)
+
 interface ClassificationEntry {
     value: any;
     classification: ts.TokenClass;
     position?: number;
 }
 
-describe("Colorization", function () {
+describe("Colorization", () => {
     // Use the shim adapter to ensure test coverage of the shim layer for the classifier
     const languageServiceAdapter = new Harness.LanguageService.ShimLanguageServiceAdapter(/*preprocessToResolve*/ false);
     const classifier = languageServiceAdapter.getClassifier();
@@ -55,8 +57,8 @@ describe("Colorization", function () {
         }
     }
 
-    describe("test getClassifications", function () {
-        it("Returns correct token classes", function () {
+    describe("test getClassifications", () => {
+        it("Returns correct token classes", () => {
             testLexicalClassification("var x: string = \"foo\"; //Hello",
                 ts.EndOfLineState.None,
                 keyword("var"),
@@ -70,7 +72,7 @@ describe("Colorization", function () {
                 punctuation(";"));
         });
 
-        it("correctly classifies a comment after a divide operator", function () {
+        it("correctly classifies a comment after a divide operator", () => {
             testLexicalClassification("1 / 2 // comment",
                 ts.EndOfLineState.None,
                 numberLiteral("1"),
@@ -80,7 +82,7 @@ describe("Colorization", function () {
                 comment("// comment"));
         });
 
-        it("correctly classifies a literal after a divide operator", function () {
+        it("correctly classifies a literal after a divide operator", () => {
             testLexicalClassification("1 / 2, 3 / 4",
                 ts.EndOfLineState.None,
                 numberLiteral("1"),
@@ -92,131 +94,131 @@ describe("Colorization", function () {
                 operator(","));
         });
 
-        it("correctly classifies a multi-line string with one backslash", function () {
+        it("correctly classifies a multi-line string with one backslash", () => {
             testLexicalClassification("'line1\\",
                 ts.EndOfLineState.None,
                 stringLiteral("'line1\\"),
                 finalEndOfLineState(ts.EndOfLineState.InSingleQuoteStringLiteral));
         });
 
-        it("correctly classifies a multi-line string with three backslashes", function () {
+        it("correctly classifies a multi-line string with three backslashes", () => {
             testLexicalClassification("'line1\\\\\\",
                 ts.EndOfLineState.None,
                 stringLiteral("'line1\\\\\\"),
                 finalEndOfLineState(ts.EndOfLineState.InSingleQuoteStringLiteral));
         });
 
-        it("correctly classifies an unterminated single-line string with no backslashes", function () {
+        it("correctly classifies an unterminated single-line string with no backslashes", () => {
             testLexicalClassification("'line1",
                 ts.EndOfLineState.None,
                 stringLiteral("'line1"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies an unterminated single-line string with two backslashes", function () {
+        it("correctly classifies an unterminated single-line string with two backslashes", () => {
             testLexicalClassification("'line1\\\\",
                 ts.EndOfLineState.None,
                 stringLiteral("'line1\\\\"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies an unterminated single-line string with four backslashes", function () {
+        it("correctly classifies an unterminated single-line string with four backslashes", () => {
             testLexicalClassification("'line1\\\\\\\\",
                 ts.EndOfLineState.None,
                 stringLiteral("'line1\\\\\\\\"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies the continuing line of a multi-line string ending in one backslash", function () {
+        it("correctly classifies the continuing line of a multi-line string ending in one backslash", () => {
             testLexicalClassification("\\",
                 ts.EndOfLineState.InDoubleQuoteStringLiteral,
                 stringLiteral("\\"),
                 finalEndOfLineState(ts.EndOfLineState.InDoubleQuoteStringLiteral));
         });
 
-        it("correctly classifies the continuing line of a multi-line string ending in three backslashes", function () {
+        it("correctly classifies the continuing line of a multi-line string ending in three backslashes", () => {
             testLexicalClassification("\\",
                 ts.EndOfLineState.InDoubleQuoteStringLiteral,
                 stringLiteral("\\"),
                 finalEndOfLineState(ts.EndOfLineState.InDoubleQuoteStringLiteral));
         });
 
-        it("correctly classifies the last line of an unterminated multi-line string ending in no backslashes", function () {
+        it("correctly classifies the last line of an unterminated multi-line string ending in no backslashes", () => {
             testLexicalClassification("  ",
                 ts.EndOfLineState.InDoubleQuoteStringLiteral,
                 stringLiteral("  "),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies the last line of an unterminated multi-line string ending in two backslashes", function () {
+        it("correctly classifies the last line of an unterminated multi-line string ending in two backslashes", () => {
             testLexicalClassification("\\\\",
                 ts.EndOfLineState.InDoubleQuoteStringLiteral,
                 stringLiteral("\\\\"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies the last line of an unterminated multi-line string ending in four backslashes", function () {
+        it("correctly classifies the last line of an unterminated multi-line string ending in four backslashes", () => {
             testLexicalClassification("\\\\\\\\",
                 ts.EndOfLineState.InDoubleQuoteStringLiteral,
                 stringLiteral("\\\\\\\\"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies the last line of a multi-line string", function () {
+        it("correctly classifies the last line of a multi-line string", () => {
             testLexicalClassification("'",
                 ts.EndOfLineState.InSingleQuoteStringLiteral,
                 stringLiteral("'"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies an unterminated multiline comment", function () {
+        it("correctly classifies an unterminated multiline comment", () => {
             testLexicalClassification("/*",
                 ts.EndOfLineState.None,
                 comment("/*"),
                 finalEndOfLineState(ts.EndOfLineState.InMultiLineCommentTrivia));
         });
 
-        it("correctly classifies the termination of a multiline comment", function () {
+        it("correctly classifies the termination of a multiline comment", () => {
             testLexicalClassification("   */     ",
                 ts.EndOfLineState.InMultiLineCommentTrivia,
                 comment("   */"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("correctly classifies the continuation of a multiline comment", function () {
+        it("correctly classifies the continuation of a multiline comment", () => {
             testLexicalClassification("LOREM IPSUM DOLOR   ",
                 ts.EndOfLineState.InMultiLineCommentTrivia,
                 comment("LOREM IPSUM DOLOR   "),
                 finalEndOfLineState(ts.EndOfLineState.InMultiLineCommentTrivia));
         });
 
-        it("correctly classifies an unterminated multiline comment on a line ending in '/*/'", function () {
+        it("correctly classifies an unterminated multiline comment on a line ending in '/*/'", () => {
             testLexicalClassification("   /*/",
                 ts.EndOfLineState.None,
                 comment("/*/"),
                 finalEndOfLineState(ts.EndOfLineState.InMultiLineCommentTrivia));
         });
 
-        it("correctly classifies an unterminated multiline comment with trailing space", function () {
+        it("correctly classifies an unterminated multiline comment with trailing space", () => {
             testLexicalClassification("/* ",
                 ts.EndOfLineState.None,
                 comment("/* "),
                 finalEndOfLineState(ts.EndOfLineState.InMultiLineCommentTrivia));
         });
 
-        it("correctly classifies a keyword after a dot", function () {
+        it("correctly classifies a keyword after a dot", () => {
             testLexicalClassification("a.var",
                 ts.EndOfLineState.None,
                 identifier("var"));
         });
 
-        it("correctly classifies a string literal after a dot", function () {
+        it("correctly classifies a string literal after a dot", () => {
             testLexicalClassification("a.\"var\"",
                 ts.EndOfLineState.None,
                 stringLiteral("\"var\""));
         });
 
-        it("correctly classifies a keyword after a dot separated by comment trivia", function () {
+        it("correctly classifies a keyword after a dot separated by comment trivia", () => {
             testLexicalClassification("a./*hello world*/ var",
                 ts.EndOfLineState.None,
                 identifier("a"),
@@ -225,21 +227,21 @@ describe("Colorization", function () {
                 identifier("var"));
         });
 
-        it("classifies a property access with whitespace around the dot", function () {
+        it("classifies a property access with whitespace around the dot", () => {
             testLexicalClassification("   x  .\tfoo ()",
                 ts.EndOfLineState.None,
                 identifier("x"),
                 identifier("foo"));
         });
 
-        it("classifies a keyword after a dot on previous line", function () {
+        it("classifies a keyword after a dot on previous line", () => {
             testLexicalClassification("var",
                 ts.EndOfLineState.None,
                 keyword("var"),
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("classifies multiple keywords properly", function () {
+        it("classifies multiple keywords properly", () => {
             testLexicalClassification("public static",
                 ts.EndOfLineState.None,
                 keyword("public"),
@@ -353,7 +355,7 @@ describe("Colorization", function () {
             }
         });
 
-        it("classifies partially written generics correctly.", function () {
+        it("classifies partially written generics correctly.", () => {
             testLexicalClassification("Foo<number",
                 ts.EndOfLineState.None,
                 identifier("Foo"),
@@ -466,7 +468,7 @@ class D { }\r\n\
                 finalEndOfLineState(ts.EndOfLineState.None));
         });
 
-        it("'of' keyword", function () {
+        it("'of' keyword", () => {
             testLexicalClassification("for (var of of of) { }",
                 ts.EndOfLineState.None,
                 keyword("for"),
diff --git a/src/harness/unittests/services/patternMatcher.ts b/src/harness/unittests/services/patternMatcher.ts
index 728636e9af2..fef382e8a3b 100644
--- a/src/harness/unittests/services/patternMatcher.ts
+++ b/src/harness/unittests/services/patternMatcher.ts
@@ -1,7 +1,7 @@
 /// <reference path="..\..\..\services\patternMatcher.ts" />
 
-describe("PatternMatcher", function () {
-    describe("BreakIntoCharacterSpans", function () {
+describe("PatternMatcher", () => {
+    describe("BreakIntoCharacterSpans", () => {
         it("EmptyIdentifier", () => {
             verifyBreakIntoCharacterSpans("");
         });
@@ -55,7 +55,7 @@ describe("PatternMatcher", function () {
         });
     });
 
-    describe("BreakIntoWordSpans", function () {
+    describe("BreakIntoWordSpans", () => {
         it("VarbatimIdentifier", () => {
             verifyBreakIntoWordSpans("@int:", "int");
         });
diff --git a/src/harness/unittests/services/preProcessFile.ts b/src/harness/unittests/services/preProcessFile.ts
index 6e77c27e4a8..1e13bc3e345 100644
--- a/src/harness/unittests/services/preProcessFile.ts
+++ b/src/harness/unittests/services/preProcessFile.ts
@@ -1,6 +1,6 @@
 /// <reference path="..\..\harnessLanguageService.ts" />
 
-describe("PreProcessFile:", function () {
+describe("PreProcessFile:", () => {
     function test(sourceText: string, readImportFile: boolean, detectJavaScriptImports: boolean, expectedPreProcess: ts.PreProcessedFileInfo): void {
         const resultPreProcess = ts.preProcessFile(sourceText, readImportFile, detectJavaScriptImports);
 
@@ -31,8 +31,8 @@ describe("PreProcessFile:", function () {
         }
     }
 
-    describe("Test preProcessFiles,", function () {
-        it("Correctly return referenced files from triple slash", function () {
+    describe("Test preProcessFiles,", () => {
+        it("Correctly return referenced files from triple slash", () => {
             test("///<reference path = \"refFile1.ts\" />" + "\n" + "///<reference path =\"refFile2.ts\"/>" + "\n" + "///<reference path=\"refFile3.ts\" />" + "\n" + "///<reference path= \"..\\refFile4d.ts\" />",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -46,7 +46,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Do not return reference path because of invalid triple-slash syntax", function () {
+        it("Do not return reference path because of invalid triple-slash syntax", () => {
             test("///<reference path\"refFile1.ts\" />" + "\n" + "///<reference path =\"refFile2.ts\">" + "\n" + "///<referencepath=\"refFile3.ts\" />" + "\n" + "///<reference pat= \"refFile4d.ts\" />",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -59,7 +59,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Correctly return imported files", function () {
+        it("Correctly return imported files", () => {
             test("import i1 = require(\"r1.ts\"); import i2 =require(\"r2.ts\"); import i3= require(\"r3.ts\"); import i4=require(\"r4.ts\"); import i5 = require  (\"r5.ts\");",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -73,7 +73,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Do not return imported files if readImportFiles argument is false", function () {
+        it("Do not return imported files if readImportFiles argument is false", () => {
             test("import i1 = require(\"r1.ts\"); import i2 =require(\"r2.ts\"); import i3= require(\"r3.ts\"); import i4=require(\"r4.ts\"); import i5 = require  (\"r5.ts\");",
                 /*readImportFile*/ false,
                 /*detectJavaScriptImports*/ false,
@@ -86,7 +86,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Do not return import path because of invalid import syntax", function () {
+        it("Do not return import path because of invalid import syntax", () => {
             test("import i1 require(\"r1.ts\"); import = require(\"r2.ts\") import i3= require(\"r3.ts\"); import i5",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -99,7 +99,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Correctly return referenced files and import files", function () {
+        it("Correctly return referenced files and import files", () => {
             test("///<reference path=\"refFile1.ts\" />" + "\n" + "///<reference path =\"refFile2.ts\"/>" + "\n" + "import i1 = require(\"r1.ts\"); import i2 =require(\"r2.ts\");",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -112,7 +112,7 @@ describe("PreProcessFile:", function () {
                 });
         }),
 
-        it("Correctly return referenced files and import files even with some invalid syntax", function () {
+        it("Correctly return referenced files and import files even with some invalid syntax", () => {
             test("///<reference path=\"refFile1.ts\" />" + "\n" + "///<reference path \"refFile2.ts\"/>" + "\n" + "import i1 = require(\"r1.ts\"); import = require(\"r2.ts\"); import i2 = require(\"r3.ts\");",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -125,7 +125,7 @@ describe("PreProcessFile:", function () {
                 });
         });
 
-        it("Correctly return ES6 imports", function () {
+        it("Correctly return ES6 imports", () => {
             test("import * as ns from \"m1\";" + "\n" +
                 "import def, * as ns from \"m2\";" + "\n" +
                 "import def from \"m3\";" + "\n" +
@@ -152,7 +152,7 @@ describe("PreProcessFile:", function () {
                 });
         });
 
-        it("Correctly return ES6 exports", function () {
+        it("Correctly return ES6 exports", () => {
             test("export * from \"m1\";" + "\n" +
                 "export {a} from \"m2\";" + "\n" +
                 "export {a as A} from \"m3\";" + "\n" +
@@ -192,7 +192,7 @@ describe("PreProcessFile:", function () {
                });
         });
 
-        it("Correctly handles export import declarations", function () {
+        it("Correctly handles export import declarations", () => {
             test("export import a = require(\"m1\");",
                 /*readImportFile*/ true,
                 /*detectJavaScriptImports*/ false,
@@ -206,7 +206,7 @@ describe("PreProcessFile:", function () {
                     isLibFile: false
                 });
         });
-        it("Correctly handles export require calls in JavaScript files", function () {
+        it("Correctly handles export require calls in JavaScript files", () => {
             test(`
             export import a = require("m1");
             var x = require('m2');
@@ -228,7 +228,7 @@ describe("PreProcessFile:", function () {
                     isLibFile: false
                 });
         });
-        it("Correctly handles dependency lists in define([deplist]) calls in JavaScript files", function () {
+        it("Correctly handles dependency lists in define([deplist]) calls in JavaScript files", () => {
             test(`
             define(["mod1", "mod2"], (m1, m2) => {
             });
@@ -246,7 +246,7 @@ describe("PreProcessFile:", function () {
                     isLibFile: false
                 });
         });
-        it("Correctly handles dependency lists in define(modName, [deplist]) calls in JavaScript files", function () {
+        it("Correctly handles dependency lists in define(modName, [deplist]) calls in JavaScript files", () => {
             test(`
             define("mod", ["mod1", "mod2"], (m1, m2) => {
             });
@@ -278,7 +278,7 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -298,8 +298,8 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "m", "pos": 123, "end": 124 },
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "m", pos: 123, end: 124 },
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -319,8 +319,8 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "m", "pos": 123, "end": 124 },
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "m", pos: 123, end: 124 },
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -340,7 +340,7 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -360,7 +360,7 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -379,7 +379,7 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "../Observable", "pos": 28, "end": 41 }
+                    { fileName: "../Observable", pos: 28, end: 41 }
                 ],
                 ambientExternalModules: undefined,
                 isLibFile: false
@@ -400,8 +400,8 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "m2", "pos": 65, "end": 67 },
-                    { "fileName": "augmentation", "pos": 102, "end": 114 }
+                    { fileName: "m2", pos: 65, end: 67 },
+                    { fileName: "augmentation", pos: 102, end: 114 }
                 ],
                 ambientExternalModules: ["m1"],
                 isLibFile: false
@@ -424,8 +424,8 @@ describe("PreProcessFile:", function () {
                 referencedFiles: [],
                 typeReferenceDirectives: [],
                 importedFiles: [
-                    { "fileName": "m2", "pos": 127, "end": 129 },
-                    { "fileName": "augmentation", "pos": 164, "end": 176 }
+                    { fileName: "m2", pos: 127, end: 129 },
+                    { fileName: "augmentation", pos: 164, end: 176 }
                 ],
                 ambientExternalModules: ["m1"],
                 isLibFile: false
@@ -442,12 +442,12 @@ describe("PreProcessFile:", function () {
             /*detectJavaScriptImports*/ false,
             {
                 referencedFiles: [
-                    { "pos": 34, "end": 35, "fileName": "a" },
-                    { "pos": 112, "end": 114, "fileName": "a2" }
+                    { pos: 34, end: 35, fileName: "a" },
+                    { pos: 112, end: 114, fileName: "a2" }
                 ],
                 typeReferenceDirectives: [
-                    { "pos": 73, "end": 75, "fileName": "a1" },
-                    { "pos": 152, "end": 154, "fileName": "a3" }
+                    { pos: 73, end: 75, fileName: "a1" },
+                    { pos: 152, end: 154, fileName: "a3" }
                 ],
                 importedFiles: [],
                 ambientExternalModules: undefined,
diff --git a/src/harness/unittests/session.ts b/src/harness/unittests/session.ts
index 3d9f782b2e0..871d4a37b9a 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -128,7 +128,7 @@ namespace ts.server {
                     body: undefined
                 });
             });
-            it ("should handle literal types in request", () => {
+            it("should handle literal types in request", () => {
                 const configureRequest: protocol.ConfigureRequest = {
                     command: CommandNames.Configure,
                     seq: 0,
@@ -186,6 +186,8 @@ namespace ts.server {
                 CommandNames.Configure,
                 CommandNames.Definition,
                 CommandNames.DefinitionFull,
+                CommandNames.DefinitionAndBoundSpan,
+                CommandNames.DefinitionAndBoundSpanFull,
                 CommandNames.Implementation,
                 CommandNames.ImplementationFull,
                 CommandNames.Exit,
@@ -315,7 +317,7 @@ namespace ts.server {
 
                 session.send = Session.prototype.send;
                 assert(session.send);
-                expect(session.send(msg)).to.not.exist;
+                expect(session.send(msg)).to.not.exist; // tslint:disable-line no-unused-expression
                 expect(lastWrittenToHost).to.equal(resultMsg);
             });
         });
@@ -352,7 +354,7 @@ namespace ts.server {
                 session.addProtocolHandler(command, () => resp);
 
                 expect(() => session.addProtocolHandler(command, () => resp))
-                .to.throw(`Protocol handler already exists for command "${command}"`);
+                    .to.throw(`Protocol handler already exists for command "${command}"`);
             });
         });
 
@@ -522,14 +524,14 @@ namespace ts.server {
             });
         });
         it("has access to the project service", () => {
-            class ServiceSession extends TestSession {
+            // tslint:disable-next-line no-unused-expression
+            new class extends TestSession {
                 constructor() {
                     super();
                     assert(this.projectService);
                     expect(this.projectService).to.be.instanceOf(ProjectService);
                 }
-            }
-            new ServiceSession();
+            }();
         });
     });
 
diff --git a/src/harness/unittests/textChanges.ts b/src/harness/unittests/textChanges.ts
index c37e50a2565..ed571b37399 100644
--- a/src/harness/unittests/textChanges.ts
+++ b/src/harness/unittests/textChanges.ts
@@ -23,60 +23,8 @@ namespace ts {
         const printerOptions = { newLine: NewLineKind.LineFeed };
         const newLineCharacter = getNewLineCharacter(printerOptions);
 
-        const getRuleProviderDefault = memoize(() => {
-            const options = {
-                indentSize: 4,
-                tabSize: 4,
-                newLineCharacter,
-                convertTabsToSpaces: true,
-                indentStyle: ts.IndentStyle.Smart,
-                insertSpaceAfterConstructor: false,
-                insertSpaceAfterCommaDelimiter: true,
-                insertSpaceAfterSemicolonInForStatements: true,
-                insertSpaceBeforeAndAfterBinaryOperators: true,
-                insertSpaceAfterKeywordsInControlFlowStatements: true,
-                insertSpaceAfterFunctionKeywordForAnonymousFunctions: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces: true,
-                insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: false,
-                insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces: false,
-                insertSpaceBeforeFunctionParenthesis: false,
-                placeOpenBraceOnNewLineForFunctions: false,
-                placeOpenBraceOnNewLineForControlBlocks: false,
-            };
-            const rulesProvider = new formatting.RulesProvider();
-            rulesProvider.ensureUpToDate(options);
-            return rulesProvider;
-        });
-        const getRuleProviderNewlineBrace = memoize(() => {
-            const options = {
-                indentSize: 4,
-                tabSize: 4,
-                newLineCharacter,
-                convertTabsToSpaces: true,
-                indentStyle: ts.IndentStyle.Smart,
-                insertSpaceAfterConstructor: false,
-                insertSpaceAfterCommaDelimiter: true,
-                insertSpaceAfterSemicolonInForStatements: true,
-                insertSpaceBeforeAndAfterBinaryOperators: true,
-                insertSpaceAfterKeywordsInControlFlowStatements: true,
-                insertSpaceAfterFunctionKeywordForAnonymousFunctions: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets: false,
-                insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces: true,
-                insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces: false,
-                insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces: false,
-                insertSpaceBeforeFunctionParenthesis: false,
-                placeOpenBraceOnNewLineForFunctions: true,
-                placeOpenBraceOnNewLineForControlBlocks: false,
-            };
-            const rulesProvider = new formatting.RulesProvider();
-            rulesProvider.ensureUpToDate(options);
-            return rulesProvider;
-        });
-        function getRuleProvider(placeOpenBraceOnNewLineForFunctions: boolean) {
-            return placeOpenBraceOnNewLineForFunctions ? getRuleProviderNewlineBrace() : getRuleProviderDefault();
+        function getRuleProvider(placeOpenBraceOnNewLineForFunctions: boolean): formatting.FormatContext {
+            return formatting.getFormatContext(placeOpenBraceOnNewLineForFunctions ? { ...testFormatOptions, placeOpenBraceOnNewLineForFunctions: true } : testFormatOptions);
         }
 
         // validate that positions that were recovered from the printed text actually match positions that will be created if the same text is parsed.
@@ -122,9 +70,9 @@ namespace ts {
 
         {
             const text = `
-namespace M 
+namespace M
 {
-    namespace M2 
+    namespace M2
     {
         function foo() {
             // comment 1
@@ -572,7 +520,7 @@ const x = 1;`;
         }
         {
             const text = `
-const x = 1, 
+const x = 1,
     y = 2;`;
             runSingleFileTest("insertNodeInListAfter6", /*placeOpenBraceOnNewLineForFunctions*/ false, text, /*validateNodes*/ false, (sourceFile, changeTracker) => {
                 changeTracker.insertNodeInListAfter(sourceFile, findChild("x", sourceFile), createVariableDeclaration("z", /*type*/ undefined, createLiteral(1)));
@@ -583,7 +531,7 @@ const x = 1,
         }
         {
             const text = `
-const /*x*/ x = 1, 
+const /*x*/ x = 1,
     /*y*/ y = 2;`;
             runSingleFileTest("insertNodeInListAfter8", /*placeOpenBraceOnNewLineForFunctions*/ false, text, /*validateNodes*/ false, (sourceFile, changeTracker) => {
                 changeTracker.insertNodeInListAfter(sourceFile, findChild("x", sourceFile), createVariableDeclaration("z", /*type*/ undefined, createLiteral(1)));
diff --git a/src/harness/unittests/transform.ts b/src/harness/unittests/transform.ts
index bcdca3e3b60..a39249bb225 100644
--- a/src/harness/unittests/transform.ts
+++ b/src/harness/unittests/transform.ts
@@ -20,6 +20,15 @@ namespace ts {
             };
             return (file: ts.SourceFile) => file;
         }
+        function replaceNumberWith2(context: ts.TransformationContext) {
+            function visitor(node: Node): Node {
+                if (isNumericLiteral(node)) {
+                    return createNumericLiteral("2");
+                }
+                return visitEachChild(node, visitor, context);
+            }
+            return (file: ts.SourceFile) => visitNode(file, visitor);
+        }
 
         function replaceIdentifiersNamedOldNameWithNewName(context: ts.TransformationContext) {
             const previousOnSubstituteNode = context.onSubstituteNode;
@@ -101,6 +110,20 @@ namespace ts {
                 }).outputText;
         });
 
+        testBaseline("transformTypesInExportDefault", () => {
+            return ts.transpileModule(`
+            export default (foo: string) => { return 1; }
+            `, {
+                    transformers: {
+                        before: [replaceNumberWith2],
+                    },
+                    compilerOptions: {
+                        target: ts.ScriptTarget.ESNext,
+                        newLine: NewLineKind.CarriageReturnLineFeed,
+                    }
+                }).outputText;
+        });
+
         testBaseline("synthesizedClassAndNamespaceCombination", () => {
             return ts.transpileModule("", {
                 transformers: {
@@ -169,6 +192,38 @@ namespace ts {
                 };
             }
         });
+
+        // https://github.com/Microsoft/TypeScript/issues/19618
+        testBaseline("transformAddImportStar", () => {
+            return ts.transpileModule("", {
+                transformers: {
+                    before: [transformAddImportStar],
+                },
+                compilerOptions: {
+                    target: ts.ScriptTarget.ES5,
+                    module: ts.ModuleKind.System,
+                    newLine: NewLineKind.CarriageReturnLineFeed,
+                }
+            }).outputText;
+
+            function transformAddImportStar(_context: ts.TransformationContext) {
+                return (sourceFile: ts.SourceFile): ts.SourceFile => {
+                    return visitNode(sourceFile);
+                };
+                function visitNode(sf: ts.SourceFile) {
+                    // produce `import * as i0 from './comp';
+                    const importStar = ts.createImportDeclaration(
+                        /*decorators*/ undefined,
+                        /*modifiers*/ undefined,
+                        /*importClause*/ ts.createImportClause(
+                            /*name*/ undefined,
+                            ts.createNamespaceImport(ts.createIdentifier("i0"))
+                        ),
+                        /*moduleSpecifier*/ ts.createLiteral("./comp1"));
+                    return ts.updateSourceFileNode(sf, [importStar]);
+                }
+            }
+        });
     });
 }
 
diff --git a/src/harness/unittests/transpile.ts b/src/harness/unittests/transpile.ts
index 16bef6500f2..7c4af8be167 100644
--- a/src/harness/unittests/transpile.ts
+++ b/src/harness/unittests/transpile.ts
@@ -149,21 +149,21 @@ var x = 0;`, {
             `import {foo} from "SomeName";\n` +
             `declare function use(a: any);\n` +
             `use(foo);`, {
-                options: { compilerOptions: { module: ModuleKind.System, newLine: NewLineKind.LineFeed }, renamedDependencies: { "SomeName": "SomeOtherName" } }
+                options: { compilerOptions: { module: ModuleKind.System, newLine: NewLineKind.LineFeed }, renamedDependencies: { SomeName: "SomeOtherName" } }
             });
 
         transpilesCorrectly("Rename dependencies - AMD",
             `import {foo} from "SomeName";\n` +
             `declare function use(a: any);\n` +
             `use(foo);`, {
-                options: { compilerOptions: { module: ModuleKind.AMD, newLine: NewLineKind.LineFeed }, renamedDependencies: { "SomeName": "SomeOtherName" } }
+                options: { compilerOptions: { module: ModuleKind.AMD, newLine: NewLineKind.LineFeed }, renamedDependencies: { SomeName: "SomeOtherName" } }
             });
 
         transpilesCorrectly("Rename dependencies - UMD",
             `import {foo} from "SomeName";\n` +
             `declare function use(a: any);\n` +
             `use(foo);`, {
-                options: { compilerOptions: { module: ModuleKind.UMD, newLine: NewLineKind.LineFeed }, renamedDependencies: { "SomeName": "SomeOtherName" } }
+                options: { compilerOptions: { module: ModuleKind.UMD, newLine: NewLineKind.LineFeed }, renamedDependencies: { SomeName: "SomeOtherName" } }
             });
 
         transpilesCorrectly("Transpile with emit decorators and emit metadata",
diff --git a/src/harness/unittests/tscWatchMode.ts b/src/harness/unittests/tscWatchMode.ts
index c5aba73f2ac..fc80a6f39ef 100644
--- a/src/harness/unittests/tscWatchMode.ts
+++ b/src/harness/unittests/tscWatchMode.ts
@@ -710,12 +710,12 @@ namespace ts.tscWatch {
                 path: "/src/tsconfig.json",
                 content: JSON.stringify(
                     {
-                        "compilerOptions": {
-                            "module": "commonjs",
-                            "target": "es5",
-                            "noImplicitAny": true,
-                            "sourceMap": false,
-                            "lib": [
+                        compilerOptions: {
+                            module: "commonjs",
+                            target: "es5",
+                            noImplicitAny: true,
+                            sourceMap: false,
+                            lib: [
                                 "es5"
                             ]
                         }
@@ -725,12 +725,12 @@ namespace ts.tscWatch {
                 path: config1.path,
                 content: JSON.stringify(
                     {
-                        "compilerOptions": {
-                            "module": "commonjs",
-                            "target": "es5",
-                            "noImplicitAny": true,
-                            "sourceMap": false,
-                            "lib": [
+                        compilerOptions: {
+                            module: "commonjs",
+                            target: "es5",
+                            noImplicitAny: true,
+                            sourceMap: false,
+                            lib: [
                                 "es5",
                                 "es2015.promise"
                             ]
@@ -1963,12 +1963,12 @@ declare module "fs" {
             const configFile: FileOrFolder = {
                 path: "/a/rootFolder/project/tsconfig.json",
                 content: JSON.stringify({
-                    "compilerOptions": {
-                        "module": "none",
-                        "allowJs": true,
-                        "outDir": "Static/scripts/"
+                    compilerOptions: {
+                        module: "none",
+                        allowJs: true,
+                        outDir: "Static/scripts/"
                     },
-                    "include": [
+                    include: [
                         "Scripts/**/*"
                     ],
                 })
@@ -1988,7 +1988,7 @@ declare module "fs" {
 
             checkProgramActualFiles(watch(), mapDefined(files, f => f === configFile ? undefined : f.path));
             file1.content = "var zz30 = 100;";
-            host.reloadFS(files, /*invokeDirectoryWatcherInsteadOfFileChanged*/ true);
+            host.reloadFS(files, { invokeDirectoryWatcherInsteadOfFileChanged: true });
             host.runQueuedTimeoutCallbacks();
 
             checkProgramActualFiles(watch(), mapDefined(files, f => f === configFile ? undefined : f.path));
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 5b6c36d071f..018934e9d7d 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -85,8 +85,7 @@ namespace ts.projectSystem {
             assert.equal(this.postExecActions.length, expectedCount, `Expected ${expectedCount} post install actions`);
         }
 
-        onProjectClosed() {
-        }
+        onProjectClosed = noop;
 
         attach(projectService: server.ProjectService) {
             this.projectService = projectService;
@@ -437,6 +436,50 @@ namespace ts.projectSystem {
         verifyDiagnostics(actual, []);
     }
 
+    function assertEvent(actualOutput: string, expectedEvent: protocol.Event, host: TestServerHost) {
+        assert.equal(actualOutput, server.formatMessage(expectedEvent, nullLogger, Utils.byteLength, host.newLine));
+    }
+
+    function checkErrorMessage(host: TestServerHost, eventName: "syntaxDiag" | "semanticDiag", diagnostics: protocol.DiagnosticEventBody) {
+        const outputs = host.getOutput();
+        assert.isTrue(outputs.length >= 1, outputs.toString());
+        const event: protocol.Event = {
+            seq: 0,
+            type: "event",
+            event: eventName,
+            body: diagnostics
+        };
+        assertEvent(outputs[0], event, host);
+    }
+
+    function checkCompleteEvent(host: TestServerHost, numberOfCurrentEvents: number, expectedSequenceId: number) {
+        const outputs = host.getOutput();
+        assert.equal(outputs.length, numberOfCurrentEvents, outputs.toString());
+        const event: protocol.RequestCompletedEvent = {
+            seq: 0,
+            type: "event",
+            event: "requestCompleted",
+            body: {
+                request_seq: expectedSequenceId
+            }
+        };
+        assertEvent(outputs[numberOfCurrentEvents - 1], event, host);
+    }
+
+    function checkProjectUpdatedInBackgroundEvent(host: TestServerHost, openFiles: string[]) {
+        const outputs = host.getOutput();
+        assert.equal(outputs.length, 1, outputs.toString());
+        const event: protocol.ProjectsUpdatedInBackgroundEvent = {
+            seq: 0,
+            type: "event",
+            event: "projectsUpdatedInBackground",
+            body: {
+                openFiles
+            }
+        };
+        assertEvent(outputs[0], event, host);
+    }
+
     describe("tsserverProjectSystem", () => {
         const commonFile1: FileOrFolder = {
             path: "/a/b/commonFile1.ts",
@@ -1248,13 +1291,13 @@ namespace ts.projectSystem {
             service.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(service.externalProjects[0], [f1.path, f2.path, libFile.path]);
 
-            const completions1 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 2);
+            const completions1 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 2, { includeExternalModuleExports: false });
             // should contain completions for string
             assert.isTrue(completions1.entries.some(e => e.name === "charAt"), "should contain 'charAt'");
             assert.isFalse(completions1.entries.some(e => e.name === "toExponential"), "should not contain 'toExponential'");
 
             service.closeClientFile(f2.path);
-            const completions2 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 2);
+            const completions2 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 2, { includeExternalModuleExports: false });
             // should contain completions for string
             assert.isFalse(completions2.entries.some(e => e.name === "charAt"), "should not contain 'charAt'");
             assert.isTrue(completions2.entries.some(e => e.name === "toExponential"), "should contain 'toExponential'");
@@ -1280,11 +1323,11 @@ namespace ts.projectSystem {
             service.checkNumberOfProjects({ externalProjects: 1 });
             checkProjectActualFiles(service.externalProjects[0], [f1.path, f2.path, libFile.path]);
 
-            const completions1 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 0);
+            const completions1 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 0, { includeExternalModuleExports: false });
             assert.isTrue(completions1.entries.some(e => e.name === "somelongname"), "should contain 'somelongname'");
 
             service.closeClientFile(f2.path);
-            const completions2 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 0);
+            const completions2 = service.externalProjects[0].getLanguageService().getCompletionsAtPosition(f1.path, 0, { includeExternalModuleExports: false });
             assert.isFalse(completions2.entries.some(e => e.name === "somelongname"), "should not contain 'somelongname'");
             const sf2 = service.externalProjects[0].getLanguageService().getProgram().getSourceFile(f2.path);
             assert.equal(sf2.text, "");
@@ -1865,7 +1908,7 @@ namespace ts.projectSystem {
             // Specify .html extension as mixed content
             const extraFileExtensions = [{ extension: ".html", scriptKind: ScriptKind.JS, isMixedContent: true }];
             const configureHostRequest = makeSessionRequest<protocol.ConfigureRequestArguments>(CommandNames.Configure, { extraFileExtensions });
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             // The configured project should now be updated to include html file
             checkNumberOfProjects(projectService, { configuredProjects: 1 });
@@ -1884,7 +1927,7 @@ namespace ts.projectSystem {
 
             // Check identifiers defined in HTML content are available in .ts file
             const project = configuredProjectAt(projectService, 0);
-            let completions = project.getLanguageService().getCompletionsAtPosition(file1.path, 1);
+            let completions = project.getLanguageService().getCompletionsAtPosition(file1.path, 1, { includeExternalModuleExports: false });
             assert(completions && completions.entries[0].name === "hello", `expected entry hello to be in completion list`);
 
             // Close HTML file
@@ -1898,7 +1941,7 @@ namespace ts.projectSystem {
             checkProjectActualFiles(configuredProjectAt(projectService, 0), [file1.path, file2.path, config.path]);
 
             // Check identifiers defined in HTML content are not available in .ts file
-            completions = project.getLanguageService().getCompletionsAtPosition(file1.path, 5);
+            completions = project.getLanguageService().getCompletionsAtPosition(file1.path, 5, { includeExternalModuleExports: false });
             assert(completions && completions.entries[0].name !== "hello", `unexpected hello entry in completion list`);
         });
 
@@ -1924,7 +1967,7 @@ namespace ts.projectSystem {
             // Specify .html extension as mixed content in a configure host request
             const extraFileExtensions = [{ extension: ".html", scriptKind: ScriptKind.JS, isMixedContent: true }];
             const configureHostRequest = makeSessionRequest<protocol.ConfigureRequestArguments>(CommandNames.Configure, { extraFileExtensions });
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             openFilesForSession([file1], session);
             let projectService = session.getProjectService();
@@ -1943,7 +1986,7 @@ namespace ts.projectSystem {
             host = createServerHost([file1, file2, config2, libFile], { executingFilePath: combinePaths(getDirectoryPath(libFile.path), "tsc.js") });
             session = createSession(host);
 
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             openFilesForSession([file1], session);
             projectService = session.getProjectService();
@@ -1962,7 +2005,7 @@ namespace ts.projectSystem {
             host = createServerHost([file1, file2, config3, libFile], { executingFilePath: combinePaths(getDirectoryPath(libFile.path), "tsc.js") });
             session = createSession(host);
 
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             openFilesForSession([file1], session);
             projectService = session.getProjectService();
@@ -1981,7 +2024,7 @@ namespace ts.projectSystem {
             host = createServerHost([file1, file2, config4, libFile], { executingFilePath: combinePaths(getDirectoryPath(libFile.path), "tsc.js") });
             session = createSession(host);
 
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             openFilesForSession([file1], session);
             projectService = session.getProjectService();
@@ -2000,7 +2043,7 @@ namespace ts.projectSystem {
             host = createServerHost([file1, file2, config5, libFile], { executingFilePath: combinePaths(getDirectoryPath(libFile.path), "tsc.js") });
             session = createSession(host);
 
-            session.executeCommand(configureHostRequest).response;
+            session.executeCommand(configureHostRequest);
 
             openFilesForSession([file1], session);
             projectService = session.getProjectService();
@@ -2602,7 +2645,7 @@ namespace ts.projectSystem {
                 projectFileName,
                 rootFiles: [toExternalFile(site.path), toExternalFile(configFile.path)],
                 options: { allowJs: false },
-                typeAcquisition: { "include": [] }
+                typeAcquisition: { include: [] }
             };
 
             projectService.openExternalProjects([externalProject]);
@@ -2762,6 +2805,7 @@ namespace ts.projectSystem {
             watchedRecursiveDirectories.push(`${root}/a/b/src`, `${root}/a/b/node_modules`);
             checkWatchedDirectories(host, watchedRecursiveDirectories, /*recursive*/ true);
         });
+
     });
 
     describe("Proper errors", () => {
@@ -2783,6 +2827,139 @@ namespace ts.projectSystem {
             const project = projectService.findProject(corruptedConfig.path);
             checkProjectRootFiles(project, [file1.path]);
         });
+
+        describe("when opening new file that doesnt exist on disk yet", () => {
+            function verifyNonExistentFile(useProjectRoot: boolean) {
+                const host = createServerHost([libFile]);
+                let hasError = false;
+                const errLogger: server.Logger = {
+                    close: noop,
+                    hasLevel: () => true,
+                    loggingEnabled: () => true,
+                    perftrc: noop,
+                    info: noop,
+                    msg: (_s, type) => {
+                        if (type === server.Msg.Err) {
+                            hasError = true;
+                        }
+                    },
+                    startGroup: noop,
+                    endGroup: noop,
+                    getLogFileName: (): string => undefined
+                };
+                const session = createSession(host, { canUseEvents: true, logger: errLogger, useInferredProjectPerProjectRoot: true });
+
+                const folderPath = "/user/someuser/projects/someFolder";
+                const projectService = session.getProjectService();
+                const untitledFile = "untitled:Untitled-1";
+                session.executeCommandSeq<protocol.OpenRequest>({
+                    command: server.CommandNames.Open,
+                    arguments: {
+                        file: untitledFile,
+                        fileContent: "",
+                        scriptKindName: "JS",
+                        projectRootPath: useProjectRoot ? folderPath : undefined
+                    }
+                });
+                checkNumberOfProjects(projectService, { inferredProjects: 1 });
+                const infoForUntitledAtProjectRoot = projectService.getScriptInfoForPath(`${folderPath.toLowerCase()}/${untitledFile.toLowerCase()}` as Path);
+                const infoForUnitiledAtRoot = projectService.getScriptInfoForPath(`/${untitledFile.toLowerCase()}` as Path);
+                if (useProjectRoot) {
+                    assert.isDefined(infoForUntitledAtProjectRoot);
+                    assert.isUndefined(infoForUnitiledAtRoot);
+                }
+                else {
+                    assert.isDefined(infoForUnitiledAtRoot);
+                    assert.isUndefined(infoForUntitledAtProjectRoot);
+                }
+                host.checkTimeoutQueueLength(2);
+
+                const newTimeoutId = host.getNextTimeoutId();
+                const expectedSequenceId = session.getNextSeq();
+                session.executeCommandSeq<protocol.GeterrRequest>({
+                    command: server.CommandNames.Geterr,
+                    arguments: {
+                        delay: 0,
+                        files: [untitledFile]
+                    }
+                });
+                host.checkTimeoutQueueLength(3);
+
+                // Run the last one = get error request
+                host.runQueuedTimeoutCallbacks(newTimeoutId);
+
+                assert.isFalse(hasError);
+                host.checkTimeoutQueueLength(2);
+                checkErrorMessage(host, "syntaxDiag", { file: untitledFile, diagnostics: [] });
+                host.clearOutput();
+
+                host.runQueuedImmediateCallbacks();
+                assert.isFalse(hasError);
+                checkErrorMessage(host, "semanticDiag", { file: untitledFile, diagnostics: [] });
+
+                checkCompleteEvent(host, 2, expectedSequenceId);
+            }
+
+            it("has projectRoot", () => {
+                verifyNonExistentFile(/*useProjectRoot*/ true);
+            });
+
+            it("does not have projectRoot", () => {
+                verifyNonExistentFile(/*useProjectRoot*/ false);
+            });
+        });
+
+        it("folder rename updates project structure and reports no errors", () => {
+            const projectDir = "/a/b/projects/myproject";
+            const app: FileOrFolder = {
+                path: `${projectDir}/bar/app.ts`,
+                content: "class Bar implements foo.Foo { getFoo() { return ''; } get2() { return 1; } }"
+            };
+            const foo: FileOrFolder = {
+                path: `${projectDir}/foo/foo.ts`,
+                content: "declare namespace foo { interface Foo { get2(): number; getFoo(): string; } }"
+            };
+            const configFile: FileOrFolder = {
+                path: `${projectDir}/tsconfig.json`,
+                content: JSON.stringify({ compilerOptions: { module: "none", targer: "es5" }, exclude: ["node_modules"] })
+            };
+            const host = createServerHost([app, foo, configFile]);
+            const session = createSession(host, { canUseEvents: true, });
+            const projectService = session.getProjectService();
+
+            session.executeCommandSeq<protocol.OpenRequest>({
+                command: server.CommandNames.Open,
+                arguments: { file: app.path, }
+            });
+            checkNumberOfProjects(projectService, { configuredProjects: 1 });
+            assert.isDefined(projectService.configuredProjects.get(configFile.path));
+            verifyErrorsInApp();
+
+            host.renameFolder(`${projectDir}/foo`, `${projectDir}/foo2`);
+            host.runQueuedTimeoutCallbacks();
+            host.runQueuedTimeoutCallbacks();
+            verifyErrorsInApp();
+
+            function verifyErrorsInApp() {
+                host.clearOutput();
+                const expectedSequenceId = session.getNextSeq();
+                session.executeCommandSeq<protocol.GeterrRequest>({
+                    command: server.CommandNames.Geterr,
+                    arguments: {
+                        delay: 0,
+                        files: [app.path]
+                    }
+                });
+                host.checkTimeoutQueueLengthAndRun(1);
+                checkErrorMessage(host, "syntaxDiag", { file: app.path, diagnostics: [] });
+                host.clearOutput();
+
+                host.runQueuedImmediateCallbacks();
+                checkErrorMessage(host, "semanticDiag", { file: app.path, diagnostics: [] });
+                checkCompleteEvent(host, 2, expectedSequenceId);
+                host.clearOutput();
+            }
+        });
     });
 
     describe("autoDiscovery", () => {
@@ -3028,12 +3205,12 @@ namespace ts.projectSystem {
                 path: "/src/tsconfig.json",
                 content: JSON.stringify(
                     {
-                        "compilerOptions": {
-                            "module": "commonjs",
-                            "target": "es5",
-                            "noImplicitAny": true,
-                            "sourceMap": false,
-                            "lib": [
+                        compilerOptions: {
+                            module: "commonjs",
+                            target: "es5",
+                            noImplicitAny: true,
+                            sourceMap: false,
+                            lib: [
                                 "es5"
                             ]
                         }
@@ -3043,12 +3220,12 @@ namespace ts.projectSystem {
                 path: config1.path,
                 content: JSON.stringify(
                     {
-                        "compilerOptions": {
-                            "module": "commonjs",
-                            "target": "es5",
-                            "noImplicitAny": true,
-                            "sourceMap": false,
-                            "lib": [
+                        compilerOptions: {
+                            module: "commonjs",
+                            target: "es5",
+                            noImplicitAny: true,
+                            sourceMap: false,
+                            lib: [
                                 "es5",
                                 "es2015.promise"
                             ]
@@ -3484,6 +3661,73 @@ namespace ts.projectSystem {
             diags = session.executeCommand(getErrRequest).response as server.protocol.Diagnostic[];
             verifyNoDiagnostics(diags);
         });
+
+        it("npm install @types works", () => {
+            const folderPath = "/a/b/projects/temp";
+            const file1: FileOrFolder = {
+                path: `${folderPath}/a.ts`,
+                content: 'import f = require("pad")'
+            };
+            const files = [file1, libFile];
+            const host = createServerHost(files);
+            const session = createSession(host, { canUseEvents: true });
+            const service = session.getProjectService();
+            session.executeCommandSeq<protocol.OpenRequest>({
+                command: server.CommandNames.Open,
+                arguments: {
+                    file: file1.path,
+                    fileContent: file1.content,
+                    scriptKindName: "TS",
+                    projectRootPath: folderPath
+                }
+            });
+            checkNumberOfProjects(service, { inferredProjects: 1 });
+            host.clearOutput();
+            const expectedSequenceId = session.getNextSeq();
+            session.executeCommandSeq<protocol.GeterrRequest>({
+                command: server.CommandNames.Geterr,
+                arguments: {
+                    delay: 0,
+                    files: [file1.path]
+                }
+            });
+
+            host.checkTimeoutQueueLengthAndRun(1);
+            checkErrorMessage(host, "syntaxDiag", { file: file1.path, diagnostics: [] });
+            host.clearOutput();
+
+            host.runQueuedImmediateCallbacks();
+            const moduleNotFound = Diagnostics.Cannot_find_module_0;
+            const startOffset = file1.content.indexOf('"') + 1;
+            checkErrorMessage(host, "semanticDiag", {
+                file: file1.path, diagnostics: [{
+                    start: { line: 1, offset: startOffset },
+                    end: { line: 1, offset: startOffset + '"pad"'.length },
+                    text: formatStringFromArgs(moduleNotFound.message, ["pad"]),
+                    code: moduleNotFound.code,
+                    category: DiagnosticCategory[moduleNotFound.category].toLowerCase()
+                }]
+            });
+            checkCompleteEvent(host, 2, expectedSequenceId);
+            host.clearOutput();
+
+            const padIndex: FileOrFolder = {
+                path: `${folderPath}/node_modules/@types/pad/index.d.ts`,
+                content: "export = pad;declare function pad(length: number, text: string, char ?: string): string;"
+            };
+            files.push(padIndex);
+            host.reloadFS(files, { ignoreWatchInvokedWithTriggerAsFileCreate: true });
+            host.runQueuedTimeoutCallbacks();
+            checkProjectUpdatedInBackgroundEvent(host, [file1.path]);
+            host.clearOutput();
+
+            host.runQueuedTimeoutCallbacks();
+            checkErrorMessage(host, "syntaxDiag", { file: file1.path, diagnostics: [] });
+            host.clearOutput();
+
+            host.runQueuedImmediateCallbacks();
+            checkErrorMessage(host, "semanticDiag", { file: file1.path, diagnostics: [] });
+        });
     });
 
     describe("Configure file diagnostics events", () => {
@@ -4564,7 +4808,7 @@ namespace ts.projectSystem {
             const host = createServerHost([f1, config]);
             const session = createSession(host, {
                 canUseEvents: true,
-                eventHandler: () => { },
+                eventHandler: noop,
                 cancellationToken
             });
             {
@@ -4701,7 +4945,7 @@ namespace ts.projectSystem {
             const host = createServerHost([f1, config]);
             const session = createSession(host, {
                 canUseEvents: true,
-                eventHandler: () => { },
+                eventHandler: noop,
                 cancellationToken,
                 throttleWaitMilliseconds: 0
             });
@@ -5330,31 +5574,31 @@ namespace ts.projectSystem {
                 const tsconfigFile: FileOrFolder = {
                     path: `${frontendDir}/tsconfig.json`,
                     content: JSON.stringify({
-                        "compilerOptions": {
-                            "strict": true,
-                            "strictNullChecks": true,
-                            "target": "es2016",
-                            "module": "commonjs",
-                            "moduleResolution": "node",
-                            "sourceMap": true,
-                            "noEmitOnError": true,
-                            "experimentalDecorators": true,
-                            "emitDecoratorMetadata": true,
+                        compilerOptions: {
+                            strict: true,
+                            strictNullChecks: true,
+                            target: "es2016",
+                            module: "commonjs",
+                            moduleResolution: "node",
+                            sourceMap: true,
+                            noEmitOnError: true,
+                            experimentalDecorators: true,
+                            emitDecoratorMetadata: true,
                             types,
-                            "noUnusedLocals": true,
-                            "outDir": "./compiled",
+                            noUnusedLocals: true,
+                            outDir: "./compiled",
                             typeRoots,
-                            "baseUrl": ".",
-                            "paths": {
+                            baseUrl: ".",
+                            paths: {
                                 "*": [
                                     "types/*"
                                 ]
                             }
                         },
-                        "include": [
+                        include: [
                             "src/**/*"
                         ],
-                        "exclude": [
+                        exclude: [
                             "node_modules",
                             "compiled"
                         ]
@@ -5479,66 +5723,66 @@ namespace ts.projectSystem {
 
                 // Simulate npm install
                 const filesAndFoldersToAdd: FileOrFolder[] = [
-                    { "path": "/a/b/node_modules" },
-                    { "path": "/a/b/node_modules/.staging/@types" },
-                    { "path": "/a/b/node_modules/.staging/lodash-b0733faa" },
-                    { "path": "/a/b/node_modules/.staging/@types/lodash-e56c4fe7" },
-                    { "path": "/a/b/node_modules/.staging/symbol-observable-24bcbbff" },
-                    { "path": "/a/b/node_modules/.staging/rxjs-22375c61" },
-                    { "path": "/a/b/node_modules/.staging/typescript-8493ea5d" },
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-                    { "path": "/a/b/node_modules/.staging/symbol-observable-24bcbbff/index.js", "content": "module.exports = require('./lib/index');\n" },
-                    { "path": "/a/b/node_modules/.staging/symbol-observable-24bcbbff/index.d.ts", "content": "declare const observableSymbol: symbol;\nexport default observableSymbol;\n" },
-                    { "path": "/a/b/node_modules/.staging/symbol-observable-24bcbbff/lib" },
-                    { "path": "/a/b/node_modules/.staging/symbol-observable-24bcbbff/lib/index.js", "content": "'use strict';\n\nObject.defineProperty(exports, \"__esModule\", {\n  value: true\n});\n\nvar _ponyfill = require('./ponyfill');\n\nvar _ponyfill2 = _interopRequireDefault(_ponyfill);\n\nfunction _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }\n\nvar root; /* global window */\n\n\nif (typeof self !== 'undefined') {\n  root = self;\n} else if (typeof window !== 'undefined') {\n  root = window;\n} else if (typeof global !== 'undefined') {\n  root = global;\n} else if (typeof module !== 'undefined') {\n  root = module;\n} else {\n  root = Function('return this')();\n}\n\nvar result = (0, _ponyfill2['default'])(root);\nexports['default'] = result;" },
+                    { path: "/a/b/node_modules" },
+                    { path: "/a/b/node_modules/.staging/@types" },
+                    { path: "/a/b/node_modules/.staging/lodash-b0733faa" },
+                    { path: "/a/b/node_modules/.staging/@types/lodash-e56c4fe7" },
+                    { path: "/a/b/node_modules/.staging/symbol-observable-24bcbbff" },
+                    { path: "/a/b/node_modules/.staging/rxjs-22375c61" },
+                    { path: "/a/b/node_modules/.staging/typescript-8493ea5d" },
+                    { path: "/a/b/node_modules/.staging/symbol-observable-24bcbbff/package.json", content: "{\n  \"name\": \"symbol-observable\",\n  \"version\": \"1.0.4\",\n  \"description\": \"Symbol.observable ponyfill\",\n  \"license\": \"MIT\",\n  \"repository\": \"blesh/symbol-observable\",\n  \"author\": {\n    \"name\": \"Ben Lesh\",\n    \"email\": \"ben@benlesh.com\"\n  },\n  \"engines\": {\n    \"node\": \">=0.10.0\"\n  },\n  \"scripts\": {\n    \"test\": \"npm run build && mocha && tsc ./ts-test/test.ts && node ./ts-test/test.js && check-es3-syntax -p lib/ --kill\",\n    \"build\": \"babel es --out-dir lib\",\n    \"prepublish\": \"npm test\"\n  },\n  \"files\": [\n    \"" },
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+                    { path: "/a/b/node_modules/.staging/typescript-8493ea5d/lib" },
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+                    { path: "/a/b/node_modules/.staging/rxjs-22375c61/package.json.2252192041", content: "{\n  \"_args\": [\n    [\n      {\n        \"raw\": \"rxjs@^5.4.2\",\n        \"scope\": null,\n        \"escapedName\": \"rxjs\",\n        \"name\": \"rxjs\",\n        \"rawSpec\": \"^5.4.2\",\n        \"spec\": \">=5.4.2 <6.0.0\",\n        \"type\": \"range\"\n      },\n      \"C:\\\\Users\\\\shkamat\\\\Desktop\\\\app\"\n    ]\n  ],\n  \"_from\": \"rxjs@>=5.4.2 <6.0.0\",\n  \"_id\": \"rxjs@5.4.3\",\n  \"_inCache\": true,\n  \"_location\": \"/rxjs\",\n  \"_nodeVersion\": \"7.7.2\",\n  \"_npmOperationalInternal\": {\n    \"host\": \"s3://npm-registry-packages\",\n    \"tmp\": \"tmp/rxjs-5.4.3.tgz_1502407898166_0.6800217325799167\"\n  },\n  \"_npmUser\": {\n    \"name\": \"blesh\",\n    \"email\": \"ben@benlesh.com\"\n  },\n  \"_npmVersion\": \"5.3.0\",\n  \"_phantomChildren\": {},\n  \"_requested\": {\n    \"raw\": \"rxjs@^5.4.2\",\n    \"scope\": null,\n    \"escapedName\": \"rxjs\",\n    \"name\": \"rxjs\",\n    \"rawSpec\": \"^5.4.2\",\n    \"spec\": \">=5.4.2 <6.0.0\",\n    \"type\": \"range\"\n  },\n  \"_requiredBy\": [\n    \"/\"\n  ],\n  \"_resolved\": \"https://registry.npmjs.org/rxjs/-/rxjs-5.4.3.tgz\",\n  \"_shasum\": \"0758cddee6033d68e0fd53676f0f3596ce3d483f\",\n  \"_shrinkwrap\": null,\n  \"_spec\": \"rxjs@^5.4.2\",\n  \"_where\": \"C:\\\\Users\\\\shkamat\\\\Desktop\\\\app\",\n  \"author\": {\n    \"name\": \"Ben Lesh\",\n    \"email\": \"ben@benlesh.com\"\n  },\n  \"bugs\": {\n    \"url\": \"https://github.com/ReactiveX/RxJS/issues\"\n  },\n  \"config\": {\n    \"commitizen\": {\n      \"path\": \"cz-conventional-changelog\"\n    }\n  },\n  \"contributors\": [\n    {\n      \"name\": \"Ben Lesh\",\n      \"email\": \"ben@benlesh.com\"\n    },\n    {\n      \"name\": \"Paul Taylor\",\n      \"email\": \"paul.e.taylor@me.com\"\n    },\n    {\n      \"name\": \"Jeff Cross\",\n      \"email\": \"crossj@google.com\"\n    },\n    {\n      \"name\": \"Matthew Podwysocki\",\n      \"email\": \"matthewp@microsoft.com\"\n    },\n    {\n      \"name\": \"OJ Kwon\",\n      \"email\": \"kwon.ohjoong@gmail.com\"\n    },\n    {\n      \"name\": \"Andre Staltz\",\n      \"email\": \"andre@staltz.com\"\n    }\n  ],\n  \"dependencies\": {\n    \"symbol-observable\": \"^1.0.1\"\n  },\n  \"description\": \"Reactive Extensions for modern JavaScript\",\n  \"devDependencies\": {\n    \"babel-polyfill\": \"^6.23.0\",\n    \"benchmark\": \"^2.1.0\",\n    \"benchpress\": \"2.0.0-beta.1\",\n    \"chai\": \"^3.5.0\",\n    \"color\": \"^0.11.1\",\n    \"colors\": \"1.1.2\",\n    \"commitizen\": \"^2.8.6\",\n    \"coveralls\": \"^2.11.13\",\n    \"cz-conventional-changelog\": \"^1.2.0\",\n    \"danger\": \"^1.1.0\",\n    \"doctoc\": \"^1.0.0\",\n    \"escape-string-regexp\": \"^1.0.5 \",\n    \"esdoc\": \"^0.4.7\",\n    \"eslint\": \"^3.8.0\",\n    \"fs-extra\": \"^2.1.2\",\n    \"get-folder-size\": \"^1.0.0\",\n    \"glob\": \"^7.0.3\",\n    \"gm\": \"^1.22.0\",\n    \"google-closure-compiler-js\": \"^20170218.0.0\",\n    \"gzip-size\": \"^3.0.0\",\n    \"http-server\": \"^0.9.0\",\n    \"husky\": \"^0.13.3\",\n    \"lint-staged\": \"3.2.5\",\n    \"lodash\": \"^4.15.0\",\n    \"madge\": \"^1.4.3\",\n    \"markdown-doctest\": \"^0.9.1\",\n    \"minimist\": \"^1.2.0\",\n    \"mkdirp\": \"^0.5.1\",\n    \"mocha\": \"^3.0.2\",\n    \"mocha-in-sauce\": \"0.0.1\",\n    \"npm-run-all\": \"^4.0.2\",\n    \"npm-scripts-info\": \"^0.3.4\",\n    \"nyc\": \"^10.2.0\",\n    \"opn-cli\": \"^3.1.0\",\n    \"platform\": \"^1.3.1\",\n    \"promise\": \"^7.1.1\",\n    \"protractor\": \"^3.1.1\",\n    \"rollup\": \"0.36.3\",\n    \"rollup-plugin-inject\": \"^2.0.0\",\n    \"rollup-plugin-node-resolve\": \"^2.0.0\",\n    \"rx\": \"latest\",\n    \"rxjs\": \"latest\",\n    \"shx\": \"^0.2.2\",\n    \"sinon\": \"^2.1.0\",\n    \"sinon-chai\": \"^2.9.0\",\n    \"source-map-support\": \"^0.4.0\",\n    \"tslib\": \"^1.5.0\",\n    \"tslint\": \"^4.4.2\",\n    \"typescript\": \"~2.0.6\",\n    \"typings\": \"^2.0.0\",\n    \"validate-commit-msg\": \"^2.14.0\",\n    \"watch\": \"^1.0.1\",\n    \"webpack\": \"^1.13.1\",\n    \"xmlhttprequest\": \"1.8.0\"\n  },\n  \"directories\": {},\n  \"dist\": {\n    \"integrity\": \"sha512-fSNi+y+P9ss+EZuV0GcIIqPUK07DEaMRUtLJvdcvMyFjc9dizuDjere+A4V7JrLGnm9iCc+nagV/4QdMTkqC4A==\",\n    \"shasum\": \"0758cddee6033d68e0fd53676f0f3596ce3d483f\",\n    \"tarball\": \"https://registry.npmjs.org/rxjs/-/rxjs-5.4.3.tgz\"\n  },\n  \"engines\": {\n    \"npm\": \">=2.0.0\"\n  },\n  \"homepage\": \"https://github.com/ReactiveX/RxJS\",\n  \"keywords\": [\n    \"Rx\",\n    \"RxJS\",\n    \"ReactiveX\",\n    \"ReactiveExtensions\",\n    \"Streams\",\n    \"Observables\",\n    \"Observable\",\n    \"Stream\",\n    \"ES6\",\n    \"ES2015\"\n  ],\n  \"license\": \"Apache-2.0\",\n  \"lint-staged\": {\n    \"*.@(js)\": [\n      \"eslint --fix\",\n      \"git add\"\n    ],\n    \"*.@(ts)\": [\n      \"tslint --fix\",\n      \"git add\"\n    ]\n  },\n  \"main\": \"Rx.js\",\n  \"maintainers\": [\n    {\n      \"name\": \"blesh\",\n      \"email\": \"ben@benlesh.com\"\n    }\n  ],\n  \"name\": \"rxjs\",\n  \"optionalDependencies\": {},\n  \"readme\": \"ERROR: No README data found!\",\n  \"repository\": {\n    \"type\": \"git\",\n    \"url\": \"git+ssh://git@github.com/ReactiveX/RxJS.git\"\n  },\n  \"scripts-info\": {\n    \"info\": \"List available script\",\n    \"build_all\": \"Build all packages (ES6, CJS, UMD) and generate packages\",\n    \"build_cjs\": \"Build CJS package with clean up existing build, copy source into dist\",\n    \"build_es6\": \"Build ES6 package with clean up existing build, copy source into dist\",\n    \"build_closure_core\": \"Minify Global core build using closure compiler\",\n    \"build_global\": \"Build Global package, then minify build\",\n    \"build_perf\": \"Build CJS & Global build, run macro performance test\",\n    \"build_test\": \"Build CJS package & test spec, execute mocha test runner\",\n    \"build_cover\": \"Run lint to current code, build CJS & test spec, execute test coverage\",\n    \"build_docs\": \"Build ES6 & global package, create documentation using it\",\n    \"build_spec\": \"Build test specs\",\n    \"check_circular_dependencies\": \"Check codebase has circular dependencies\",\n    \"clean_spec\": \"Clean up existing test spec build output\",\n    \"clean_dist_cjs\": \"Clean up existing CJS package output\",\n    \"clean_dist_es6\": \"Clean up existing ES6 package output\",\n    \"clean_dist_global\": \"Clean up existing Global package output\",\n    \"commit\": \"Run git commit wizard\",\n    \"compile_dist_cjs\": \"Compile codebase into CJS module\",\n    \"compile_module_es6\": \"Compile codebase into ES6\",\n    \"cover\": \"Execute test coverage\",\n    \"lint_perf\": \"Run lint against performance test suite\",\n    \"lint_spec\": \"Run lint against test spec\",\n    \"lint_src\": \"Run lint against source\",\n    \"lint\": \"Run lint against everything\",\n    \"perf\": \"Run macro performance benchmark\",\n    \"perf_micro\": \"Run micro performance benchmark\",\n    \"test_mocha\": \"Execute mocha test runner against existing test spec build\",\n    \"test_browser\": \"Execute mocha test runner on browser against existing test spec build\",\n    \"test\": \"Clean up existing test spec build, build test spec and execute mocha test runner\",\n    \"tests2png\": \"Generate marble diagram image from test spec\",\n    \"watch\": \"Watch codebase, trigger compile when source code changes\"\n  },\n  \"typings\": \"Rx.d.ts\",\n  \"version\": \"5.4.3\"\n}\n" }
                 ].map(getRootedFileOrFolder));
-                verifyAfterPartialOrCompleteNpmInstall(0);
+                verifyAfterPartialOrCompleteNpmInstall(2);
 
                 // remove /a/b/node_modules/.staging/rxjs-22375c61/package.json.2252192041
                 filesAndFoldersToAdd.length--;
                 // and add few more folders/files
                 filesAndFoldersToAdd.push(...[
-                    { "path": "/a/b/node_modules/symbol-observable" },
-                    { "path": "/a/b/node_modules/@types" },
-                    { "path": "/a/b/node_modules/@types/lodash" },
-                    { "path": "/a/b/node_modules/lodash" },
-                    { "path": "/a/b/node_modules/rxjs" },
-                    { "path": "/a/b/node_modules/typescript" },
-                    { "path": "/a/b/node_modules/.bin" }
+                    { path: "/a/b/node_modules/symbol-observable" },
+                    { path: "/a/b/node_modules/@types" },
+                    { path: "/a/b/node_modules/@types/lodash" },
+                    { path: "/a/b/node_modules/lodash" },
+                    { path: "/a/b/node_modules/rxjs" },
+                    { path: "/a/b/node_modules/typescript" },
+                    { path: "/a/b/node_modules/.bin" }
                 ].map(getRootedFileOrFolder));
                 // From the type root update
                 verifyAfterPartialOrCompleteNpmInstall(2);
diff --git a/src/harness/unittests/typingsInstaller.ts b/src/harness/unittests/typingsInstaller.ts
index 65d904940b3..e321fb1c99d 100644
--- a/src/harness/unittests/typingsInstaller.ts
+++ b/src/harness/unittests/typingsInstaller.ts
@@ -776,8 +776,8 @@ namespace ts.projectSystem {
             const bowerJson = {
                 path: "/bower.json",
                 content: JSON.stringify({
-                    "dependencies": {
-                        "jquery": "^3.1.0"
+                    dependencies: {
+                        jquery: "^3.1.0"
                     }
                 })
             };
@@ -1012,7 +1012,7 @@ namespace ts.projectSystem {
             const packageJson = {
                 path: "/a/b/package.json",
                 content: JSON.stringify({
-                    "dependencies": {
+                    dependencies: {
                         "; say ‘Hello from TypeScript!’ #": "0.0.x"
                     }
                 })
@@ -1095,7 +1095,7 @@ namespace ts.projectSystem {
                 content: ""
             };
             const host = createServerHost([f, node]);
-            const cache = createMapFromTemplate<string>({ "node": node.path });
+            const cache = createMapFromTemplate<string>({ node: node.path });
             const logger = trackingLogger();
             const result = JsTyping.discoverTypings(host, logger.log, [f.path], getDirectoryPath(<Path>f.path), emptySafeList, cache, { enable: true }, ["fs", "bar"]);
             assert.deepEqual(logger.finish(), [
@@ -1145,7 +1145,7 @@ namespace ts.projectSystem {
             };
             const packageFile = {
                 path: "/a/package.json",
-                content: JSON.stringify({ dependencies: { "commander": "1.0.0" } })
+                content: JSON.stringify({ dependencies: { commander: "1.0.0" } })
             };
             const cachePath = "/a/cache/";
             const commander = {
@@ -1195,7 +1195,7 @@ namespace ts.projectSystem {
             };
             const packageFile = {
                 path: "/a/package.json",
-                content: JSON.stringify({ dependencies: { "commander": "1.0.0" } })
+                content: JSON.stringify({ dependencies: { commander: "1.0.0" } })
             };
             const cachePath = "/a/cache/";
             const commander = {
@@ -1247,7 +1247,7 @@ namespace ts.projectSystem {
             };
             const packageFile = {
                 path: "/a/package.json",
-                content: JSON.stringify({ dependencies: { "commander": "1.0.0" } })
+                content: JSON.stringify({ dependencies: { commander: "1.0.0" } })
             };
             const cachePath = "/a/cache/";
             const host = createServerHost([f1, packageFile]);
diff --git a/src/harness/virtualFileSystemWithWatch.ts b/src/harness/virtualFileSystemWithWatch.ts
index d6b1fc1a771..25581093f3d 100644
--- a/src/harness/virtualFileSystemWithWatch.ts
+++ b/src/harness/virtualFileSystemWithWatch.ts
@@ -182,6 +182,10 @@ interface Array<T> {}`
         private map: TimeOutCallback[] = [];
         private nextId = 1;
 
+        getNextId() {
+            return this.nextId;
+        }
+
         register(cb: (...args: any[]) => void, args: any[]) {
             const timeoutId = this.nextId;
             this.nextId++;
@@ -203,7 +207,13 @@ interface Array<T> {}`
             return n;
         }
 
-        invoke() {
+        invoke(invokeKey?: number) {
+            if (invokeKey) {
+                this.map[invokeKey]();
+                delete this.map[invokeKey];
+                return;
+            }
+
             // Note: invoking a callback may result in new callbacks been queued,
             // so do not clear the entire callback list regardless. Only remove the
             // ones we have invoked.
@@ -226,6 +236,11 @@ interface Array<T> {}`
         directoryName: string;
     }
 
+    export interface ReloadWatchInvokeOptions {
+        invokeDirectoryWatcherInsteadOfFileChanged: boolean;
+        ignoreWatchInvokedWithTriggerAsFileCreate: boolean;
+    }
+
     export class TestServerHost implements server.ServerHost, FormatDiagnosticsHost {
         args: string[] = [];
 
@@ -270,7 +285,7 @@ interface Array<T> {}`
             return s;
         }
 
-        reloadFS(fileOrFolderList: ReadonlyArray<FileOrFolder>, invokeDirectoryWatcherInsteadOfFileChanged?: boolean) {
+        reloadFS(fileOrFolderList: ReadonlyArray<FileOrFolder>, options?: Partial<ReloadWatchInvokeOptions>) {
             const mapNewLeaves = createMap<true>();
             const isNewFs = this.fs.size === 0;
             fileOrFolderList = fileOrFolderList.concat(this.withSafeList ? safeList : []);
@@ -291,7 +306,7 @@ interface Array<T> {}`
                             // Update file
                             if (currentEntry.content !== fileOrDirectory.content) {
                                 currentEntry.content = fileOrDirectory.content;
-                                if (invokeDirectoryWatcherInsteadOfFileChanged) {
+                                if (options && options.invokeDirectoryWatcherInsteadOfFileChanged) {
                                     this.invokeDirectoryWatcher(getDirectoryPath(currentEntry.fullPath), currentEntry.fullPath);
                                 }
                                 else {
@@ -314,7 +329,7 @@ interface Array<T> {}`
                     }
                 }
                 else {
-                    this.ensureFileOrFolder(fileOrDirectory);
+                    this.ensureFileOrFolder(fileOrDirectory, options && options.ignoreWatchInvokedWithTriggerAsFileCreate);
                 }
             }
 
@@ -331,12 +346,45 @@ interface Array<T> {}`
             }
         }
 
-        ensureFileOrFolder(fileOrDirectory: FileOrFolder) {
+        renameFolder(folderName: string, newFolderName: string) {
+            const fullPath = getNormalizedAbsolutePath(folderName, this.currentDirectory);
+            const path = this.toPath(fullPath);
+            const folder = this.fs.get(path) as Folder;
+            Debug.assert(!!folder);
+
+            // Only remove the folder
+            this.removeFileOrFolder(folder, returnFalse, /*isRenaming*/ true);
+
+            // Add updated folder with new folder name
+            const newFullPath = getNormalizedAbsolutePath(newFolderName, this.currentDirectory);
+            const newFolder = this.toFolder(newFullPath);
+            const newPath = newFolder.path;
+            const basePath = getDirectoryPath(path);
+            Debug.assert(basePath !== path);
+            Debug.assert(basePath === getDirectoryPath(newPath));
+            const baseFolder = this.fs.get(basePath) as Folder;
+            this.addFileOrFolderInFolder(baseFolder, newFolder);
+
+            // Invoke watches for files in the folder as deleted (from old path)
+            for (const entry of folder.entries) {
+                Debug.assert(isFile(entry));
+                this.fs.delete(entry.path);
+                this.invokeFileWatcher(entry.fullPath, FileWatcherEventKind.Deleted);
+
+                entry.fullPath = combinePaths(newFullPath, getBaseFileName(entry.fullPath));
+                entry.path = this.toPath(entry.fullPath);
+                newFolder.entries.push(entry);
+                this.fs.set(entry.path, entry);
+                this.invokeFileWatcher(entry.fullPath, FileWatcherEventKind.Created);
+            }
+        }
+
+        ensureFileOrFolder(fileOrDirectory: FileOrFolder, ignoreWatchInvokedWithTriggerAsFileCreate?: boolean) {
             if (isString(fileOrDirectory.content)) {
                 const file = this.toFile(fileOrDirectory);
                 Debug.assert(!this.fs.get(file.path));
                 const baseFolder = this.ensureFolder(getDirectoryPath(file.fullPath));
-                this.addFileOrFolderInFolder(baseFolder, file);
+                this.addFileOrFolderInFolder(baseFolder, file, ignoreWatchInvokedWithTriggerAsFileCreate);
             }
             else {
                 const fullPath = getNormalizedAbsolutePath(fileOrDirectory.path, this.currentDirectory);
@@ -365,17 +413,20 @@ interface Array<T> {}`
             return folder;
         }
 
-        private addFileOrFolderInFolder(folder: Folder, fileOrDirectory: File | Folder) {
+        private addFileOrFolderInFolder(folder: Folder, fileOrDirectory: File | Folder, ignoreWatch?: boolean) {
             folder.entries.push(fileOrDirectory);
             this.fs.set(fileOrDirectory.path, fileOrDirectory);
 
+            if (ignoreWatch) {
+                return;
+            }
             if (isFile(fileOrDirectory)) {
                 this.invokeFileWatcher(fileOrDirectory.fullPath, FileWatcherEventKind.Created);
             }
             this.invokeDirectoryWatcher(folder.fullPath, fileOrDirectory.fullPath);
         }
 
-        private removeFileOrFolder(fileOrDirectory: File | Folder, isRemovableLeafFolder: (folder: Folder) => boolean) {
+        private removeFileOrFolder(fileOrDirectory: File | Folder, isRemovableLeafFolder: (folder: Folder) => boolean, isRenaming?: boolean) {
             const basePath = getDirectoryPath(fileOrDirectory.path);
             const baseFolder = this.fs.get(basePath) as Folder;
             if (basePath !== fileOrDirectory.path) {
@@ -388,7 +439,7 @@ interface Array<T> {}`
                 this.invokeFileWatcher(fileOrDirectory.fullPath, FileWatcherEventKind.Deleted);
             }
             else {
-                Debug.assert(fileOrDirectory.entries.length === 0);
+                Debug.assert(fileOrDirectory.entries.length === 0 || isRenaming);
                 const relativePath = this.getRelativePathToDirectory(fileOrDirectory.fullPath, fileOrDirectory.fullPath);
                 // Invoke directory and recursive directory watcher for the folder
                 // Here we arent invoking recursive directory watchers for the base folders
@@ -545,6 +596,10 @@ interface Array<T> {}`
             return this.timeoutCallbacks.register(callback, args);
         }
 
+        getNextTimeoutId() {
+            return this.timeoutCallbacks.getNextId();
+        }
+
         clearTimeout(timeoutId: any): void {
             this.timeoutCallbacks.unregister(timeoutId);
         }
@@ -559,9 +614,9 @@ interface Array<T> {}`
             assert.equal(callbacksCount, expected, `expected ${expected} timeout callbacks queued but found ${callbacksCount}.`);
         }
 
-        runQueuedTimeoutCallbacks() {
+        runQueuedTimeoutCallbacks(timeoutId?: number) {
             try {
-                this.timeoutCallbacks.invoke();
+                this.timeoutCallbacks.invoke(timeoutId);
             }
             catch (e) {
                 if (e.message === this.existMessage) {
diff --git a/src/lib/dom.generated.d.ts b/src/lib/dom.generated.d.ts
index e4104715446..ec488bb069e 100644
--- a/src/lib/dom.generated.d.ts
+++ b/src/lib/dom.generated.d.ts
@@ -203,7 +203,7 @@ interface IDBIndexParameters {
 
 interface IDBObjectStoreParameters {
     autoIncrement?: boolean;
-    keyPath?: IDBKeyPath | null;
+    keyPath?: string | string[];
 }
 
 interface IntersectionObserverEntryInit {
@@ -773,7 +773,7 @@ interface RequestInit {
     body?: any;
     cache?: RequestCache;
     credentials?: RequestCredentials;
-    headers?: Headers | string[][];
+    headers?: HeadersInit;
     integrity?: string;
     keepalive?: boolean;
     method?: string;
@@ -785,7 +785,7 @@ interface RequestInit {
 }
 
 interface ResponseInit {
-    headers?: Headers | string[][];
+    headers?: HeadersInit;
     status?: number;
     statusText?: string;
 }
@@ -1255,10 +1255,10 @@ interface ApplicationCache extends EventTarget {
     readonly OBSOLETE: number;
     readonly UNCACHED: number;
     readonly UPDATEREADY: number;
-    addEventListener<K extends keyof ApplicationCacheEventMap>(type: K, listener: (this: ApplicationCache, ev: ApplicationCacheEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ApplicationCacheEventMap>(type: K, listener: (this: ApplicationCache, ev: ApplicationCacheEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ApplicationCacheEventMap>(type: K, listener: (this: ApplicationCache, ev: ApplicationCacheEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ApplicationCacheEventMap>(type: K, listener: (this: ApplicationCache, ev: ApplicationCacheEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ApplicationCache: {
@@ -1314,10 +1314,10 @@ interface AudioBufferSourceNode extends AudioNode {
     readonly playbackRate: AudioParam;
     start(when?: number, offset?: number, duration?: number): void;
     stop(when?: number): void;
-    addEventListener<K extends keyof AudioBufferSourceNodeEventMap>(type: K, listener: (this: AudioBufferSourceNode, ev: AudioBufferSourceNodeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof AudioBufferSourceNodeEventMap>(type: K, listener: (this: AudioBufferSourceNode, ev: AudioBufferSourceNodeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof AudioBufferSourceNodeEventMap>(type: K, listener: (this: AudioBufferSourceNode, ev: AudioBufferSourceNodeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof AudioBufferSourceNodeEventMap>(type: K, listener: (this: AudioBufferSourceNode, ev: AudioBufferSourceNodeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var AudioBufferSourceNode: {
@@ -1358,10 +1358,10 @@ interface AudioContextBase extends EventTarget {
     createWaveShaper(): WaveShaperNode;
     decodeAudioData(audioData: ArrayBuffer, successCallback?: DecodeSuccessCallback, errorCallback?: DecodeErrorCallback): Promise<AudioBuffer>;
     resume(): Promise<void>;
-    addEventListener<K extends keyof AudioContextEventMap>(type: K, listener: (this: AudioContext, ev: AudioContextEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof AudioContextEventMap>(type: K, listener: (this: AudioContext, ev: AudioContextEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof AudioContextEventMap>(type: K, listener: (this: AudioContext, ev: AudioContextEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof AudioContextEventMap>(type: K, listener: (this: AudioContext, ev: AudioContextEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface AudioContext extends AudioContextBase {
@@ -1468,10 +1468,10 @@ interface AudioTrackList extends EventTarget {
     onremovetrack: (this: AudioTrackList, ev: TrackEvent) => any;
     getTrackById(id: string): AudioTrack | null;
     item(index: number): AudioTrack;
-    addEventListener<K extends keyof AudioTrackListEventMap>(type: K, listener: (this: AudioTrackList, ev: AudioTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof AudioTrackListEventMap>(type: K, listener: (this: AudioTrackList, ev: AudioTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof AudioTrackListEventMap>(type: K, listener: (this: AudioTrackList, ev: AudioTrackListEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof AudioTrackListEventMap>(type: K, listener: (this: AudioTrackList, ev: AudioTrackListEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [index: number]: AudioTrack;
 }
 
@@ -2386,10 +2386,10 @@ declare var CustomEvent: {
 
 interface DataCue extends TextTrackCue {
     data: ArrayBuffer;
-    addEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: DataCue, ev: TextTrackCueEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: DataCue, ev: TextTrackCueEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: DataCue, ev: TextTrackCueEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: DataCue, ev: TextTrackCueEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var DataCue: {
@@ -3311,10 +3311,10 @@ interface Document extends Node, GlobalEventHandlers, NodeSelector, DocumentEven
      * @param content The text and HTML tags to write.
      */
     writeln(...content: string[]): void;
-    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: Document, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: Document, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: Document, ev: DocumentEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: Document, ev: DocumentEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Document: {
@@ -3638,10 +3638,10 @@ interface Element extends Node, GlobalEventHandlers, ElementTraversal, NodeSelec
     insertAdjacentHTML(where: InsertPosition, html: string): void;
     insertAdjacentText(where: InsertPosition, text: string): void;
     attachShadow(shadowRootInitDict: ShadowRootInit): ShadowRoot;
-    addEventListener<K extends keyof ElementEventMap>(type: K, listener: (this: Element, ev: ElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ElementEventMap>(type: K, listener: (this: Element, ev: ElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ElementEventMap>(type: K, listener: (this: Element, ev: ElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ElementEventMap>(type: K, listener: (this: Element, ev: ElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Element: {
@@ -3777,10 +3777,10 @@ interface FileReader extends EventTarget, MSBaseReader {
     readAsBinaryString(blob: Blob): void;
     readAsDataURL(blob: Blob): void;
     readAsText(blob: Blob, encoding?: string): void;
-    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var FileReader: {
@@ -3901,7 +3901,7 @@ interface Headers {
 
 declare var Headers: {
     prototype: Headers;
-    new(init?: Headers | string[][] | object): Headers;
+    new(init?: HeadersInit): Headers;
 };
 
 interface History {
@@ -4012,10 +4012,10 @@ interface HTMLAnchorElement extends HTMLElement {
      * Returns a string representation of an object.
      */
     toString(): string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAnchorElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAnchorElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAnchorElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAnchorElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLAnchorElement: {
@@ -4088,10 +4088,10 @@ interface HTMLAppletElement extends HTMLElement {
     useMap: string;
     vspace: number;
     width: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAppletElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAppletElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAppletElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAppletElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLAppletElement: {
@@ -4158,10 +4158,10 @@ interface HTMLAreaElement extends HTMLElement {
      * Returns a string representation of an object.
      */
     toString(): string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAreaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAreaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAreaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLAreaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLAreaElement: {
@@ -4178,10 +4178,10 @@ declare var HTMLAreasCollection: {
 };
 
 interface HTMLAudioElement extends HTMLMediaElement {
-    addEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLAudioElement, ev: HTMLMediaElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLAudioElement, ev: HTMLMediaElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLAudioElement, ev: HTMLMediaElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLAudioElement, ev: HTMLMediaElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLAudioElement: {
@@ -4198,10 +4198,10 @@ interface HTMLBaseElement extends HTMLElement {
      * Sets or retrieves the window or frame at which to target content.
      */
     target: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLBaseElement: {
@@ -4218,10 +4218,10 @@ interface HTMLBaseFontElement extends HTMLElement, DOML2DeprecatedColorProperty
      * Sets or retrieves the font size of the object.
      */
     size: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseFontElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseFontElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseFontElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBaseFontElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLBaseFontElement: {
@@ -4274,10 +4274,10 @@ interface HTMLBodyElement extends HTMLElement {
     onunload: (this: HTMLBodyElement, ev: Event) => any;
     text: any;
     vLink: any;
-    addEventListener<K extends keyof HTMLBodyElementEventMap>(type: K, listener: (this: HTMLBodyElement, ev: HTMLBodyElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLBodyElementEventMap>(type: K, listener: (this: HTMLBodyElement, ev: HTMLBodyElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLBodyElementEventMap>(type: K, listener: (this: HTMLBodyElement, ev: HTMLBodyElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLBodyElementEventMap>(type: K, listener: (this: HTMLBodyElement, ev: HTMLBodyElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLBodyElement: {
@@ -4290,10 +4290,10 @@ interface HTMLBRElement extends HTMLElement {
      * Sets or retrieves the side on which floating objects are not to be positioned when any IHTMLBlockElement is inserted into the document.
      */
     clear: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBRElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBRElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBRElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLBRElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLBRElement: {
@@ -4365,10 +4365,10 @@ interface HTMLButtonElement extends HTMLElement {
      * @param error Sets a custom error message that is displayed when a form is submitted.
      */
     setCustomValidity(error: string): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLButtonElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLButtonElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLButtonElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLButtonElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLButtonElement: {
@@ -4402,10 +4402,10 @@ interface HTMLCanvasElement extends HTMLElement {
      */
     toDataURL(type?: string, ...args: any[]): string;
     toBlob(callback: (result: Blob | null) => void, type?: string, ...arguments: any[]): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLCanvasElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLCanvasElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLCanvasElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLCanvasElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLCanvasElement: {
@@ -4439,10 +4439,10 @@ declare var HTMLCollection: {
 
 interface HTMLDataElement extends HTMLElement {
     value: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDataElement: {
@@ -4452,10 +4452,10 @@ declare var HTMLDataElement: {
 
 interface HTMLDataListElement extends HTMLElement {
     options: HTMLCollectionOf<HTMLOptionElement>;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDataListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDataListElement: {
@@ -4465,10 +4465,10 @@ declare var HTMLDataListElement: {
 
 interface HTMLDirectoryElement extends HTMLElement {
     compact: boolean;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDirectoryElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDirectoryElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDirectoryElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDirectoryElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDirectoryElement: {
@@ -4485,10 +4485,10 @@ interface HTMLDivElement extends HTMLElement {
      * Sets or retrieves whether the browser automatically performs wordwrap.
      */
     noWrap: boolean;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDivElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDivElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDivElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDivElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDivElement: {
@@ -4498,10 +4498,10 @@ declare var HTMLDivElement: {
 
 interface HTMLDListElement extends HTMLElement {
     compact: boolean;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLDListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDListElement: {
@@ -4510,10 +4510,10 @@ declare var HTMLDListElement: {
 };
 
 interface HTMLDocument extends Document {
-    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: HTMLDocument, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: HTMLDocument, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: HTMLDocument, ev: DocumentEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: HTMLDocument, ev: DocumentEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLDocument: {
@@ -4685,10 +4685,10 @@ interface HTMLElement extends Element {
     dragDrop(): boolean;
     focus(): void;
     msGetInputContext(): MSInputMethodContext;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLElement: {
@@ -4743,10 +4743,10 @@ interface HTMLEmbedElement extends HTMLElement, GetSVGDocument {
      * Sets or retrieves the width of the object.
      */
     width: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLEmbedElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLEmbedElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLEmbedElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLEmbedElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLEmbedElement: {
@@ -4786,10 +4786,10 @@ interface HTMLFieldSetElement extends HTMLElement {
      * @param error Sets a custom error message that is displayed when a form is submitted.
      */
     setCustomValidity(error: string): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFieldSetElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFieldSetElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFieldSetElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFieldSetElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLFieldSetElement: {
@@ -4802,10 +4802,10 @@ interface HTMLFontElement extends HTMLElement, DOML2DeprecatedColorProperty, DOM
      * Sets or retrieves the current typeface family.
      */
     face: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFontElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFontElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFontElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFontElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLFontElement: {
@@ -4890,10 +4890,10 @@ interface HTMLFormElement extends HTMLElement {
      */
     submit(): void;
     reportValidity(): boolean;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFormElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFormElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFormElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFormElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [name: string]: any;
 }
 
@@ -4967,10 +4967,10 @@ interface HTMLFrameElement extends HTMLElement, GetSVGDocument {
      * Sets or retrieves the width of the object.
      */
     width: string | number;
-    addEventListener<K extends keyof HTMLFrameElementEventMap>(type: K, listener: (this: HTMLFrameElement, ev: HTMLFrameElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLFrameElementEventMap>(type: K, listener: (this: HTMLFrameElement, ev: HTMLFrameElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLFrameElementEventMap>(type: K, listener: (this: HTMLFrameElement, ev: HTMLFrameElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLFrameElementEventMap>(type: K, listener: (this: HTMLFrameElement, ev: HTMLFrameElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLFrameElement: {
@@ -5037,10 +5037,10 @@ interface HTMLFrameSetElement extends HTMLElement {
      * Sets or retrieves the frame heights of the object.
      */
     rows: string;
-    addEventListener<K extends keyof HTMLFrameSetElementEventMap>(type: K, listener: (this: HTMLFrameSetElement, ev: HTMLFrameSetElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLFrameSetElementEventMap>(type: K, listener: (this: HTMLFrameSetElement, ev: HTMLFrameSetElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLFrameSetElementEventMap>(type: K, listener: (this: HTMLFrameSetElement, ev: HTMLFrameSetElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLFrameSetElementEventMap>(type: K, listener: (this: HTMLFrameSetElement, ev: HTMLFrameSetElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLFrameSetElement: {
@@ -5050,10 +5050,10 @@ declare var HTMLFrameSetElement: {
 
 interface HTMLHeadElement extends HTMLElement {
     profile: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLHeadElement: {
@@ -5066,10 +5066,10 @@ interface HTMLHeadingElement extends HTMLElement {
      * Sets or retrieves a value that indicates the table alignment.
      */
     align: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadingElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadingElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadingElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHeadingElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLHeadingElement: {
@@ -5090,10 +5090,10 @@ interface HTMLHRElement extends HTMLElement, DOML2DeprecatedColorProperty, DOML2
      * Sets or retrieves the width of the object.
      */
     width: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHRElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHRElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHRElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHRElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLHRElement: {
@@ -5106,10 +5106,10 @@ interface HTMLHtmlElement extends HTMLElement {
      * Sets or retrieves the DTD version that governs the current document.
      */
     version: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHtmlElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHtmlElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHtmlElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLHtmlElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLHtmlElement: {
@@ -5193,10 +5193,10 @@ interface HTMLIFrameElement extends HTMLElement, GetSVGDocument {
      * Sets or retrieves the width of the object.
      */
     width: string;
-    addEventListener<K extends keyof HTMLIFrameElementEventMap>(type: K, listener: (this: HTMLIFrameElement, ev: HTMLIFrameElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLIFrameElementEventMap>(type: K, listener: (this: HTMLIFrameElement, ev: HTMLIFrameElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLIFrameElementEventMap>(type: K, listener: (this: HTMLIFrameElement, ev: HTMLIFrameElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLIFrameElementEventMap>(type: K, listener: (this: HTMLIFrameElement, ev: HTMLIFrameElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLIFrameElement: {
@@ -5286,10 +5286,10 @@ interface HTMLImageElement extends HTMLElement {
     readonly x: number;
     readonly y: number;
     msGetAsCastingSource(): any;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLImageElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLImageElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLImageElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLImageElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLImageElement: {
@@ -5500,10 +5500,10 @@ interface HTMLInputElement extends HTMLElement {
      * @param n Value to increment the value by.
      */
     stepUp(n?: number): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLInputElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLInputElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLInputElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLInputElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLInputElement: {
@@ -5520,10 +5520,10 @@ interface HTMLLabelElement extends HTMLElement {
      * Sets or retrieves the object to which the given label object is assigned.
      */
     htmlFor: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLabelElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLabelElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLabelElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLabelElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLLabelElement: {
@@ -5540,10 +5540,10 @@ interface HTMLLegendElement extends HTMLElement {
      * Retrieves a reference to the form that the object is embedded in.
      */
     readonly form: HTMLFormElement | null;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLegendElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLegendElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLegendElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLegendElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLLegendElement: {
@@ -5557,10 +5557,10 @@ interface HTMLLIElement extends HTMLElement {
      * Sets or retrieves the value of a list item.
      */
     value: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLIElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLIElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLIElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLIElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLLIElement: {
@@ -5604,10 +5604,10 @@ interface HTMLLinkElement extends HTMLElement, LinkStyle {
     type: string;
     import?: Document;
     integrity: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLinkElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLinkElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLinkElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLLinkElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLLinkElement: {
@@ -5624,10 +5624,10 @@ interface HTMLMapElement extends HTMLElement {
      * Sets or retrieves the name of the object.
      */
     name: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMapElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMapElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMapElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMapElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMapElement: {
@@ -5658,10 +5658,10 @@ interface HTMLMarqueeElement extends HTMLElement {
     width: string;
     start(): void;
     stop(): void;
-    addEventListener<K extends keyof HTMLMarqueeElementEventMap>(type: K, listener: (this: HTMLMarqueeElement, ev: HTMLMarqueeElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLMarqueeElementEventMap>(type: K, listener: (this: HTMLMarqueeElement, ev: HTMLMarqueeElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLMarqueeElementEventMap>(type: K, listener: (this: HTMLMarqueeElement, ev: HTMLMarqueeElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLMarqueeElementEventMap>(type: K, listener: (this: HTMLMarqueeElement, ev: HTMLMarqueeElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMarqueeElement: {
@@ -5842,10 +5842,10 @@ interface HTMLMediaElement extends HTMLElement {
     readonly NETWORK_IDLE: number;
     readonly NETWORK_LOADING: number;
     readonly NETWORK_NO_SOURCE: number;
-    addEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLMediaElement, ev: HTMLMediaElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLMediaElement, ev: HTMLMediaElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLMediaElement, ev: HTMLMediaElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLMediaElementEventMap>(type: K, listener: (this: HTMLMediaElement, ev: HTMLMediaElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMediaElement: {
@@ -5865,10 +5865,10 @@ declare var HTMLMediaElement: {
 interface HTMLMenuElement extends HTMLElement {
     compact: boolean;
     type: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMenuElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMenuElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMenuElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMenuElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMenuElement: {
@@ -5901,10 +5901,10 @@ interface HTMLMetaElement extends HTMLElement {
      * Sets or retrieves the URL property that will be loaded after the specified time has elapsed.
      */
     url: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMetaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMetaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMetaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMetaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMetaElement: {
@@ -5919,10 +5919,10 @@ interface HTMLMeterElement extends HTMLElement {
     min: number;
     optimum: number;
     value: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMeterElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMeterElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMeterElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLMeterElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLMeterElement: {
@@ -5939,10 +5939,10 @@ interface HTMLModElement extends HTMLElement {
      * Sets or retrieves the date and time of a modification to the object.
      */
     dateTime: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLModElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLModElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLModElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLModElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLModElement: {
@@ -6058,10 +6058,10 @@ interface HTMLObjectElement extends HTMLElement, GetSVGDocument {
      * @param error Sets a custom error message that is displayed when a form is submitted.
      */
     setCustomValidity(error: string): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLObjectElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLObjectElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLObjectElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLObjectElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLObjectElement: {
@@ -6076,10 +6076,10 @@ interface HTMLOListElement extends HTMLElement {
      */
     start: number;
     type: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLOListElement: {
@@ -6117,10 +6117,10 @@ interface HTMLOptGroupElement extends HTMLElement {
      * Sets or retrieves the value which is returned to the server when the form control is submitted.
      */
     value: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptGroupElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptGroupElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptGroupElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptGroupElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLOptGroupElement: {
@@ -6158,10 +6158,10 @@ interface HTMLOptionElement extends HTMLElement {
      * Sets or retrieves the value which is returned to the server when the form control is submitted.
      */
     value: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOptionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLOptionElement: {
@@ -6194,10 +6194,10 @@ interface HTMLOutputElement extends HTMLElement {
     checkValidity(): boolean;
     reportValidity(): boolean;
     setCustomValidity(error: string): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOutputElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOutputElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOutputElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLOutputElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLOutputElement: {
@@ -6211,10 +6211,10 @@ interface HTMLParagraphElement extends HTMLElement {
      */
     align: string;
     clear: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParagraphElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParagraphElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParagraphElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParagraphElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLParagraphElement: {
@@ -6239,10 +6239,10 @@ interface HTMLParamElement extends HTMLElement {
      * Sets or retrieves the data type of the value attribute.
      */
     valueType: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParamElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParamElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParamElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLParamElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLParamElement: {
@@ -6251,10 +6251,10 @@ declare var HTMLParamElement: {
 };
 
 interface HTMLPictureElement extends HTMLElement {
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPictureElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPictureElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPictureElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPictureElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLPictureElement: {
@@ -6267,10 +6267,10 @@ interface HTMLPreElement extends HTMLElement {
      * Sets or gets a value that you can use to implement your own width functionality for the object.
      */
     width: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPreElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPreElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPreElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLPreElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLPreElement: {
@@ -6295,10 +6295,10 @@ interface HTMLProgressElement extends HTMLElement {
      * Sets or gets the current value of a progress element. The value must be a non-negative number between 0 and the max value.
      */
     value: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLProgressElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLProgressElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLProgressElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLProgressElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLProgressElement: {
@@ -6311,10 +6311,10 @@ interface HTMLQuoteElement extends HTMLElement {
      * Sets or retrieves reference information about the object.
      */
     cite: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLQuoteElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLQuoteElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLQuoteElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLQuoteElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLQuoteElement: {
@@ -6354,10 +6354,10 @@ interface HTMLScriptElement extends HTMLElement {
      */
     type: string;
     integrity: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLScriptElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLScriptElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLScriptElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLScriptElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLScriptElement: {
@@ -6452,10 +6452,10 @@ interface HTMLSelectElement extends HTMLElement {
      * @param error Sets a custom error message that is displayed when a form is submitted.
      */
     setCustomValidity(error: string): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSelectElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSelectElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSelectElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSelectElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [name: string]: any;
 }
 
@@ -6480,10 +6480,10 @@ interface HTMLSourceElement extends HTMLElement {
      * Gets or sets the MIME type of a media resource.
      */
     type: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSourceElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSourceElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSourceElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSourceElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLSourceElement: {
@@ -6492,10 +6492,10 @@ declare var HTMLSourceElement: {
 };
 
 interface HTMLSpanElement extends HTMLElement {
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSpanElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSpanElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSpanElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLSpanElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLSpanElement: {
@@ -6513,10 +6513,10 @@ interface HTMLStyleElement extends HTMLElement, LinkStyle {
      * Retrieves the CSS language in which the style sheet is written.
      */
     type: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLStyleElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLStyleElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLStyleElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLStyleElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLStyleElement: {
@@ -6533,10 +6533,10 @@ interface HTMLTableCaptionElement extends HTMLElement {
      * Sets or retrieves whether the caption appears at the top or bottom of the table.
      */
     vAlign: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCaptionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCaptionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCaptionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCaptionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableCaptionElement: {
@@ -6590,10 +6590,10 @@ interface HTMLTableCellElement extends HTMLElement, HTMLTableAlignment {
      * Sets or retrieves the width of the object.
      */
     width: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableCellElement: {
@@ -6614,10 +6614,10 @@ interface HTMLTableColElement extends HTMLElement, HTMLTableAlignment {
      * Sets or retrieves the width of the object.
      */
     width: any;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableColElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableColElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableColElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableColElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableColElement: {
@@ -6626,10 +6626,10 @@ declare var HTMLTableColElement: {
 };
 
 interface HTMLTableDataCellElement extends HTMLTableCellElement {
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableDataCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableDataCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableDataCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableDataCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableDataCellElement: {
@@ -6741,10 +6741,10 @@ interface HTMLTableElement extends HTMLElement {
      * @param index Number that specifies where to insert the row in the rows collection. The default value is -1, which appends the new row to the end of the rows collection.
      */
     insertRow(index?: number): HTMLTableRowElement;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableElement: {
@@ -6757,10 +6757,10 @@ interface HTMLTableHeaderCellElement extends HTMLTableCellElement {
      * Sets or retrieves the group of cells in a table to which the object's information applies.
      */
     scope: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableHeaderCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableHeaderCellElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableHeaderCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableHeaderCellElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableHeaderCellElement: {
@@ -6800,10 +6800,10 @@ interface HTMLTableRowElement extends HTMLElement, HTMLTableAlignment {
      * @param index Number that specifies where to insert the cell in the tr. The default value is -1, which appends the new cell to the end of the cells collection.
      */
     insertCell(index?: number): HTMLTableDataCellElement;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableRowElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableRowElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableRowElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableRowElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableRowElement: {
@@ -6830,10 +6830,10 @@ interface HTMLTableSectionElement extends HTMLElement, HTMLTableAlignment {
      * @param index Number that specifies where to insert the row in the rows collection. The default value is -1, which appends the new row to the end of the rows collection.
      */
     insertRow(index?: number): HTMLTableRowElement;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableSectionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableSectionElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableSectionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTableSectionElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTableSectionElement: {
@@ -6843,10 +6843,10 @@ declare var HTMLTableSectionElement: {
 
 interface HTMLTemplateElement extends HTMLElement {
     readonly content: DocumentFragment;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTemplateElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTemplateElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTemplateElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTemplateElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTemplateElement: {
@@ -6952,10 +6952,10 @@ interface HTMLTextAreaElement extends HTMLElement {
      * @param end The offset into the text field for the end of the selection.
      */
     setSelectionRange(start: number, end: number): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTextAreaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTextAreaElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTextAreaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTextAreaElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTextAreaElement: {
@@ -6965,10 +6965,10 @@ declare var HTMLTextAreaElement: {
 
 interface HTMLTimeElement extends HTMLElement {
     dateTime: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTimeElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTimeElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTimeElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTimeElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTimeElement: {
@@ -6981,10 +6981,10 @@ interface HTMLTitleElement extends HTMLElement {
      * Retrieves or sets the text of the object as a string.
      */
     text: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTitleElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTitleElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTitleElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTitleElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTitleElement: {
@@ -7004,10 +7004,10 @@ interface HTMLTrackElement extends HTMLElement {
     readonly LOADED: number;
     readonly LOADING: number;
     readonly NONE: number;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTrackElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTrackElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTrackElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLTrackElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLTrackElement: {
@@ -7022,10 +7022,10 @@ declare var HTMLTrackElement: {
 interface HTMLUListElement extends HTMLElement {
     compact: boolean;
     type: string;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUListElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUListElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLUListElement: {
@@ -7034,10 +7034,10 @@ declare var HTMLUListElement: {
 };
 
 interface HTMLUnknownElement extends HTMLElement {
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUnknownElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUnknownElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUnknownElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLUnknownElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLUnknownElement: {
@@ -7091,10 +7091,10 @@ interface HTMLVideoElement extends HTMLMediaElement {
     webkitEnterFullScreen(): void;
     webkitExitFullscreen(): void;
     webkitExitFullScreen(): void;
-    addEventListener<K extends keyof HTMLVideoElementEventMap>(type: K, listener: (this: HTMLVideoElement, ev: HTMLVideoElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLVideoElementEventMap>(type: K, listener: (this: HTMLVideoElement, ev: HTMLVideoElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLVideoElementEventMap>(type: K, listener: (this: HTMLVideoElement, ev: HTMLVideoElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLVideoElementEventMap>(type: K, listener: (this: HTMLVideoElement, ev: HTMLVideoElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var HTMLVideoElement: {
@@ -7151,11 +7151,12 @@ interface IDBDatabase extends EventTarget {
     createObjectStore(name: string, optionalParameters?: IDBObjectStoreParameters): IDBObjectStore;
     deleteObjectStore(name: string): void;
     transaction(storeNames: string | string[], mode?: IDBTransactionMode): IDBTransaction;
-    addEventListener(type: "versionchange", listener: (ev: IDBVersionChangeEvent) => any, useCapture?: boolean): void;
-    addEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener(type: "versionchange", listener: (this: IDBDatabase, ev: IDBVersionChangeEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener(type: "versionchange", listener: (this: IDBDatabase, ev: IDBVersionChangeEvent) => any, options?: boolean | EventListenerOptions): void;
+    addEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBDatabase: {
@@ -7239,10 +7240,10 @@ interface IDBOpenDBRequestEventMap extends IDBRequestEventMap {
 interface IDBOpenDBRequest extends IDBRequest {
     onblocked: (this: IDBOpenDBRequest, ev: Event) => any;
     onupgradeneeded: (this: IDBOpenDBRequest, ev: IDBVersionChangeEvent) => any;
-    addEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBOpenDBRequest: {
@@ -7263,10 +7264,10 @@ interface IDBRequest extends EventTarget {
     readonly result: any;
     source: IDBObjectStore | IDBIndex | IDBCursor;
     readonly transaction: IDBTransaction;
-    addEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBRequest: {
@@ -7292,10 +7293,10 @@ interface IDBTransaction extends EventTarget {
     readonly READ_ONLY: string;
     readonly READ_WRITE: string;
     readonly VERSION_CHANGE: string;
-    addEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBTransaction: {
@@ -7464,10 +7465,10 @@ interface MediaDevices extends EventTarget {
     enumerateDevices(): Promise<MediaDeviceInfo[]>;
     getSupportedConstraints(): MediaTrackSupportedConstraints;
     getUserMedia(constraints: MediaStreamConstraints): Promise<MediaStream>;
-    addEventListener<K extends keyof MediaDevicesEventMap>(type: K, listener: (this: MediaDevices, ev: MediaDevicesEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MediaDevicesEventMap>(type: K, listener: (this: MediaDevices, ev: MediaDevicesEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MediaDevicesEventMap>(type: K, listener: (this: MediaDevices, ev: MediaDevicesEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MediaDevicesEventMap>(type: K, listener: (this: MediaDevices, ev: MediaDevicesEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MediaDevices: {
@@ -7638,10 +7639,10 @@ interface MediaStream extends EventTarget {
     getVideoTracks(): MediaStreamTrack[];
     removeTrack(track: MediaStreamTrack): void;
     stop(): void;
-    addEventListener<K extends keyof MediaStreamEventMap>(type: K, listener: (this: MediaStream, ev: MediaStreamEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MediaStreamEventMap>(type: K, listener: (this: MediaStream, ev: MediaStreamEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MediaStreamEventMap>(type: K, listener: (this: MediaStream, ev: MediaStreamEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MediaStreamEventMap>(type: K, listener: (this: MediaStream, ev: MediaStreamEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MediaStream: {
@@ -7712,10 +7713,10 @@ interface MediaStreamTrack extends EventTarget {
     getConstraints(): MediaTrackConstraints;
     getSettings(): MediaTrackSettings;
     stop(): void;
-    addEventListener<K extends keyof MediaStreamTrackEventMap>(type: K, listener: (this: MediaStreamTrack, ev: MediaStreamTrackEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MediaStreamTrackEventMap>(type: K, listener: (this: MediaStreamTrack, ev: MediaStreamTrackEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MediaStreamTrackEventMap>(type: K, listener: (this: MediaStreamTrack, ev: MediaStreamTrackEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MediaStreamTrackEventMap>(type: K, listener: (this: MediaStreamTrack, ev: MediaStreamTrackEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MediaStreamTrack: {
@@ -7764,10 +7765,10 @@ interface MessagePort extends EventTarget {
     close(): void;
     postMessage(message?: any, transfer?: any[]): void;
     start(): void;
-    addEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MessagePort: {
@@ -7871,10 +7872,10 @@ interface MSAppAsyncOperation extends EventTarget {
     readonly COMPLETED: number;
     readonly ERROR: number;
     readonly STARTED: number;
-    addEventListener<K extends keyof MSAppAsyncOperationEventMap>(type: K, listener: (this: MSAppAsyncOperation, ev: MSAppAsyncOperationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSAppAsyncOperationEventMap>(type: K, listener: (this: MSAppAsyncOperation, ev: MSAppAsyncOperationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSAppAsyncOperationEventMap>(type: K, listener: (this: MSAppAsyncOperation, ev: MSAppAsyncOperationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSAppAsyncOperationEventMap>(type: K, listener: (this: MSAppAsyncOperation, ev: MSAppAsyncOperationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MSAppAsyncOperation: {
@@ -8029,10 +8030,10 @@ interface MSHTMLWebViewElement extends HTMLElement {
     navigateWithHttpRequestMessage(requestMessage: any): void;
     refresh(): void;
     stop(): void;
-    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: MSHTMLWebViewElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: MSHTMLWebViewElement, ev: HTMLElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: MSHTMLWebViewElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: MSHTMLWebViewElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MSHTMLWebViewElement: {
@@ -8057,10 +8058,10 @@ interface MSInputMethodContext extends EventTarget {
     getCompositionAlternatives(): string[];
     hasComposition(): boolean;
     isCandidateWindowVisible(): boolean;
-    addEventListener<K extends keyof MSInputMethodContextEventMap>(type: K, listener: (this: MSInputMethodContext, ev: MSInputMethodContextEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSInputMethodContextEventMap>(type: K, listener: (this: MSInputMethodContext, ev: MSInputMethodContextEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSInputMethodContextEventMap>(type: K, listener: (this: MSInputMethodContext, ev: MSInputMethodContextEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSInputMethodContextEventMap>(type: K, listener: (this: MSInputMethodContext, ev: MSInputMethodContextEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MSInputMethodContext: {
@@ -8225,10 +8226,10 @@ interface MSStreamReader extends EventTarget, MSBaseReader {
     readAsBlob(stream: MSStream, size?: number): void;
     readAsDataURL(stream: MSStream, size?: number): void;
     readAsText(stream: MSStream, encoding?: string, size?: number): void;
-    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSStreamReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSStreamReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSStreamReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSStreamReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MSStreamReader: {
@@ -8256,10 +8257,10 @@ interface MSWebViewAsyncOperation extends EventTarget {
     readonly TYPE_CAPTURE_PREVIEW_TO_RANDOM_ACCESS_STREAM: number;
     readonly TYPE_CREATE_DATA_PACKAGE_FROM_SELECTION: number;
     readonly TYPE_INVOKE_SCRIPT: number;
-    addEventListener<K extends keyof MSWebViewAsyncOperationEventMap>(type: K, listener: (this: MSWebViewAsyncOperation, ev: MSWebViewAsyncOperationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSWebViewAsyncOperationEventMap>(type: K, listener: (this: MSWebViewAsyncOperation, ev: MSWebViewAsyncOperationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSWebViewAsyncOperationEventMap>(type: K, listener: (this: MSWebViewAsyncOperation, ev: MSWebViewAsyncOperationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSWebViewAsyncOperationEventMap>(type: K, listener: (this: MSWebViewAsyncOperation, ev: MSWebViewAsyncOperationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MSWebViewAsyncOperation: {
@@ -8549,10 +8550,10 @@ interface Notification extends EventTarget {
     readonly tag: string;
     readonly title: string;
     close(): void;
-    addEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Notification: {
@@ -8631,10 +8632,10 @@ interface OfflineAudioContext extends AudioContextBase {
     oncomplete: (this: OfflineAudioContext, ev: OfflineAudioCompletionEvent) => any;
     startRendering(): Promise<AudioBuffer>;
     suspend(suspendTime: number): Promise<void>;
-    addEventListener<K extends keyof OfflineAudioContextEventMap>(type: K, listener: (this: OfflineAudioContext, ev: OfflineAudioContextEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof OfflineAudioContextEventMap>(type: K, listener: (this: OfflineAudioContext, ev: OfflineAudioContextEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof OfflineAudioContextEventMap>(type: K, listener: (this: OfflineAudioContext, ev: OfflineAudioContextEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof OfflineAudioContextEventMap>(type: K, listener: (this: OfflineAudioContext, ev: OfflineAudioContextEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var OfflineAudioContext: {
@@ -8654,10 +8655,10 @@ interface OscillatorNode extends AudioNode {
     setPeriodicWave(periodicWave: PeriodicWave): void;
     start(when?: number): void;
     stop(when?: number): void;
-    addEventListener<K extends keyof OscillatorNodeEventMap>(type: K, listener: (this: OscillatorNode, ev: OscillatorNodeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof OscillatorNodeEventMap>(type: K, listener: (this: OscillatorNode, ev: OscillatorNodeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof OscillatorNodeEventMap>(type: K, listener: (this: OscillatorNode, ev: OscillatorNodeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof OscillatorNodeEventMap>(type: K, listener: (this: OscillatorNode, ev: OscillatorNodeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var OscillatorNode: {
@@ -8751,10 +8752,10 @@ interface PaymentRequest extends EventTarget {
     readonly shippingType: PaymentShippingType | null;
     abort(): Promise<void>;
     show(): Promise<PaymentResponse>;
-    addEventListener<K extends keyof PaymentRequestEventMap>(type: K, listener: (this: PaymentRequest, ev: PaymentRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof PaymentRequestEventMap>(type: K, listener: (this: PaymentRequest, ev: PaymentRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof PaymentRequestEventMap>(type: K, listener: (this: PaymentRequest, ev: PaymentRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof PaymentRequestEventMap>(type: K, listener: (this: PaymentRequest, ev: PaymentRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var PaymentRequest: {
@@ -9260,10 +9261,10 @@ interface RTCDtlsTransport extends RTCStatsProvider {
     getRemoteParameters(): RTCDtlsParameters | null;
     start(remoteParameters: RTCDtlsParameters): void;
     stop(): void;
-    addEventListener<K extends keyof RTCDtlsTransportEventMap>(type: K, listener: (this: RTCDtlsTransport, ev: RTCDtlsTransportEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCDtlsTransportEventMap>(type: K, listener: (this: RTCDtlsTransport, ev: RTCDtlsTransportEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCDtlsTransportEventMap>(type: K, listener: (this: RTCDtlsTransport, ev: RTCDtlsTransportEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCDtlsTransportEventMap>(type: K, listener: (this: RTCDtlsTransport, ev: RTCDtlsTransportEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCDtlsTransport: {
@@ -9292,10 +9293,10 @@ interface RTCDtmfSender extends EventTarget {
     readonly sender: RTCRtpSender;
     readonly toneBuffer: string;
     insertDTMF(tones: string, duration?: number, interToneGap?: number): void;
-    addEventListener<K extends keyof RTCDtmfSenderEventMap>(type: K, listener: (this: RTCDtmfSender, ev: RTCDtmfSenderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCDtmfSenderEventMap>(type: K, listener: (this: RTCDtmfSender, ev: RTCDtmfSenderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCDtmfSenderEventMap>(type: K, listener: (this: RTCDtmfSender, ev: RTCDtmfSenderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCDtmfSenderEventMap>(type: K, listener: (this: RTCDtmfSender, ev: RTCDtmfSenderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCDtmfSender: {
@@ -9345,10 +9346,10 @@ interface RTCIceGatherer extends RTCStatsProvider {
     createAssociatedGatherer(): RTCIceGatherer;
     getLocalCandidates(): RTCIceCandidateDictionary[];
     getLocalParameters(): RTCIceParameters;
-    addEventListener<K extends keyof RTCIceGathererEventMap>(type: K, listener: (this: RTCIceGatherer, ev: RTCIceGathererEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCIceGathererEventMap>(type: K, listener: (this: RTCIceGatherer, ev: RTCIceGathererEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCIceGathererEventMap>(type: K, listener: (this: RTCIceGatherer, ev: RTCIceGathererEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCIceGathererEventMap>(type: K, listener: (this: RTCIceGatherer, ev: RTCIceGathererEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCIceGatherer: {
@@ -9385,10 +9386,10 @@ interface RTCIceTransport extends RTCStatsProvider {
     setRemoteCandidates(remoteCandidates: RTCIceCandidateDictionary[]): void;
     start(gatherer: RTCIceGatherer, remoteParameters: RTCIceParameters, role?: RTCIceRole): void;
     stop(): void;
-    addEventListener<K extends keyof RTCIceTransportEventMap>(type: K, listener: (this: RTCIceTransport, ev: RTCIceTransportEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCIceTransportEventMap>(type: K, listener: (this: RTCIceTransport, ev: RTCIceTransportEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCIceTransportEventMap>(type: K, listener: (this: RTCIceTransport, ev: RTCIceTransportEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCIceTransportEventMap>(type: K, listener: (this: RTCIceTransport, ev: RTCIceTransportEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCIceTransport: {
@@ -9442,10 +9443,10 @@ interface RTCPeerConnection extends EventTarget {
     removeStream(stream: MediaStream): void;
     setLocalDescription(description: RTCSessionDescription, successCallback?: VoidFunction, failureCallback?: RTCPeerConnectionErrorCallback): Promise<void>;
     setRemoteDescription(description: RTCSessionDescription, successCallback?: VoidFunction, failureCallback?: RTCPeerConnectionErrorCallback): Promise<void>;
-    addEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: RTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: RTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: RTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: RTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCPeerConnection: {
@@ -9476,10 +9477,10 @@ interface RTCRtpReceiver extends RTCStatsProvider {
     requestSendCSRC(csrc: number): void;
     setTransport(transport: RTCDtlsTransport | RTCSrtpSdesTransport, rtcpTransport?: RTCDtlsTransport): void;
     stop(): void;
-    addEventListener<K extends keyof RTCRtpReceiverEventMap>(type: K, listener: (this: RTCRtpReceiver, ev: RTCRtpReceiverEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCRtpReceiverEventMap>(type: K, listener: (this: RTCRtpReceiver, ev: RTCRtpReceiverEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCRtpReceiverEventMap>(type: K, listener: (this: RTCRtpReceiver, ev: RTCRtpReceiverEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCRtpReceiverEventMap>(type: K, listener: (this: RTCRtpReceiver, ev: RTCRtpReceiverEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCRtpReceiver: {
@@ -9503,10 +9504,10 @@ interface RTCRtpSender extends RTCStatsProvider {
     setTrack(track: MediaStreamTrack): void;
     setTransport(transport: RTCDtlsTransport | RTCSrtpSdesTransport, rtcpTransport?: RTCDtlsTransport): void;
     stop(): void;
-    addEventListener<K extends keyof RTCRtpSenderEventMap>(type: K, listener: (this: RTCRtpSender, ev: RTCRtpSenderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCRtpSenderEventMap>(type: K, listener: (this: RTCRtpSender, ev: RTCRtpSenderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCRtpSenderEventMap>(type: K, listener: (this: RTCRtpSender, ev: RTCRtpSenderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCRtpSenderEventMap>(type: K, listener: (this: RTCRtpSender, ev: RTCRtpSenderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCRtpSender: {
@@ -9533,10 +9534,10 @@ interface RTCSrtpSdesTransportEventMap {
 interface RTCSrtpSdesTransport extends EventTarget {
     onerror: ((this: RTCSrtpSdesTransport, ev: Event) => any) | null;
     readonly transport: RTCIceTransport;
-    addEventListener<K extends keyof RTCSrtpSdesTransportEventMap>(type: K, listener: (this: RTCSrtpSdesTransport, ev: RTCSrtpSdesTransportEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCSrtpSdesTransportEventMap>(type: K, listener: (this: RTCSrtpSdesTransport, ev: RTCSrtpSdesTransportEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCSrtpSdesTransportEventMap>(type: K, listener: (this: RTCSrtpSdesTransport, ev: RTCSrtpSdesTransportEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCSrtpSdesTransportEventMap>(type: K, listener: (this: RTCSrtpSdesTransport, ev: RTCSrtpSdesTransportEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var RTCSrtpSdesTransport: {
@@ -9607,10 +9608,10 @@ interface Screen extends EventTarget {
     readonly width: number;
     msLockOrientation(orientations: string | string[]): boolean;
     msUnlockOrientation(): void;
-    addEventListener<K extends keyof ScreenEventMap>(type: K, listener: (this: Screen, ev: ScreenEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ScreenEventMap>(type: K, listener: (this: Screen, ev: ScreenEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ScreenEventMap>(type: K, listener: (this: Screen, ev: ScreenEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ScreenEventMap>(type: K, listener: (this: Screen, ev: ScreenEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Screen: {
@@ -9635,10 +9636,10 @@ interface ScriptProcessorNodeEventMap {
 interface ScriptProcessorNode extends AudioNode {
     readonly bufferSize: number;
     onaudioprocess: (this: ScriptProcessorNode, ev: AudioProcessingEvent) => any;
-    addEventListener<K extends keyof ScriptProcessorNodeEventMap>(type: K, listener: (this: ScriptProcessorNode, ev: ScriptProcessorNodeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ScriptProcessorNodeEventMap>(type: K, listener: (this: ScriptProcessorNode, ev: ScriptProcessorNodeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ScriptProcessorNodeEventMap>(type: K, listener: (this: ScriptProcessorNode, ev: ScriptProcessorNodeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ScriptProcessorNodeEventMap>(type: K, listener: (this: ScriptProcessorNode, ev: ScriptProcessorNodeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ScriptProcessorNode: {
@@ -9689,10 +9690,10 @@ interface ServiceWorker extends EventTarget, AbstractWorker {
     readonly scriptURL: USVString;
     readonly state: ServiceWorkerState;
     postMessage(message: any, transfer?: any[]): void;
-    addEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorker: {
@@ -9713,10 +9714,10 @@ interface ServiceWorkerContainer extends EventTarget {
     getRegistration(): Promise<ServiceWorkerRegistration | undefined>;
     getRegistrations(): Promise<ServiceWorkerRegistration[]>;
     register(scriptURL: USVString, options?: RegistrationOptions): Promise<ServiceWorkerRegistration>;
-    addEventListener<K extends keyof ServiceWorkerContainerEventMap>(type: K, listener: (this: ServiceWorkerContainer, ev: ServiceWorkerContainerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerContainerEventMap>(type: K, listener: (this: ServiceWorkerContainer, ev: ServiceWorkerContainerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerContainerEventMap>(type: K, listener: (this: ServiceWorkerContainer, ev: ServiceWorkerContainerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerContainerEventMap>(type: K, listener: (this: ServiceWorkerContainer, ev: ServiceWorkerContainerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorkerContainer: {
@@ -9753,10 +9754,10 @@ interface ServiceWorkerRegistration extends EventTarget {
     showNotification(title: string, options?: NotificationOptions): Promise<void>;
     unregister(): Promise<boolean>;
     update(): Promise<void>;
-    addEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorkerRegistration: {
@@ -9809,10 +9810,10 @@ interface SpeechSynthesis extends EventTarget {
     pause(): void;
     resume(): void;
     speak(utterance: SpeechSynthesisUtterance): void;
-    addEventListener<K extends keyof SpeechSynthesisEventMap>(type: K, listener: (this: SpeechSynthesis, ev: SpeechSynthesisEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SpeechSynthesisEventMap>(type: K, listener: (this: SpeechSynthesis, ev: SpeechSynthesisEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SpeechSynthesisEventMap>(type: K, listener: (this: SpeechSynthesis, ev: SpeechSynthesisEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SpeechSynthesisEventMap>(type: K, listener: (this: SpeechSynthesis, ev: SpeechSynthesisEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SpeechSynthesis: {
@@ -9856,10 +9857,10 @@ interface SpeechSynthesisUtterance extends EventTarget {
     text: string;
     voice: SpeechSynthesisVoice;
     volume: number;
-    addEventListener<K extends keyof SpeechSynthesisUtteranceEventMap>(type: K, listener: (this: SpeechSynthesisUtterance, ev: SpeechSynthesisUtteranceEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SpeechSynthesisUtteranceEventMap>(type: K, listener: (this: SpeechSynthesisUtterance, ev: SpeechSynthesisUtteranceEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SpeechSynthesisUtteranceEventMap>(type: K, listener: (this: SpeechSynthesisUtterance, ev: SpeechSynthesisUtteranceEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SpeechSynthesisUtteranceEventMap>(type: K, listener: (this: SpeechSynthesisUtterance, ev: SpeechSynthesisUtteranceEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SpeechSynthesisUtterance: {
@@ -9993,10 +9994,10 @@ declare var SubtleCrypto: {
 
 interface SVGAElement extends SVGGraphicsElement, SVGURIReference {
     readonly target: SVGAnimatedString;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGAElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGAElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGAElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGAElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGAElement: {
@@ -10152,10 +10153,10 @@ interface SVGCircleElement extends SVGGraphicsElement {
     readonly cx: SVGAnimatedLength;
     readonly cy: SVGAnimatedLength;
     readonly r: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGCircleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGCircleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGCircleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGCircleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGCircleElement: {
@@ -10165,10 +10166,10 @@ declare var SVGCircleElement: {
 
 interface SVGClipPathElement extends SVGGraphicsElement, SVGUnitTypes {
     readonly clipPathUnits: SVGAnimatedEnumeration;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGClipPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGClipPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGClipPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGClipPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGClipPathElement: {
@@ -10190,10 +10191,10 @@ interface SVGComponentTransferFunctionElement extends SVGElement {
     readonly SVG_FECOMPONENTTRANSFER_TYPE_LINEAR: number;
     readonly SVG_FECOMPONENTTRANSFER_TYPE_TABLE: number;
     readonly SVG_FECOMPONENTTRANSFER_TYPE_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGComponentTransferFunctionElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGComponentTransferFunctionElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGComponentTransferFunctionElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGComponentTransferFunctionElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGComponentTransferFunctionElement: {
@@ -10208,10 +10209,10 @@ declare var SVGComponentTransferFunctionElement: {
 };
 
 interface SVGDefsElement extends SVGGraphicsElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDefsElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDefsElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDefsElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDefsElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGDefsElement: {
@@ -10220,10 +10221,10 @@ declare var SVGDefsElement: {
 };
 
 interface SVGDescElement extends SVGElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDescElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDescElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDescElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGDescElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGDescElement: {
@@ -10260,10 +10261,10 @@ interface SVGElement extends Element {
     readonly style: CSSStyleDeclaration;
     readonly viewportElement: SVGElement;
     xmlbase: string;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGElement: {
@@ -10302,10 +10303,10 @@ interface SVGEllipseElement extends SVGGraphicsElement {
     readonly cy: SVGAnimatedLength;
     readonly rx: SVGAnimatedLength;
     readonly ry: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGEllipseElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGEllipseElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGEllipseElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGEllipseElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGEllipseElement: {
@@ -10334,10 +10335,10 @@ interface SVGFEBlendElement extends SVGElement, SVGFilterPrimitiveStandardAttrib
     readonly SVG_FEBLEND_MODE_SCREEN: number;
     readonly SVG_FEBLEND_MODE_SOFT_LIGHT: number;
     readonly SVG_FEBLEND_MODE_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEBlendElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEBlendElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEBlendElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEBlendElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEBlendElement: {
@@ -10371,10 +10372,10 @@ interface SVGFEColorMatrixElement extends SVGElement, SVGFilterPrimitiveStandard
     readonly SVG_FECOLORMATRIX_TYPE_MATRIX: number;
     readonly SVG_FECOLORMATRIX_TYPE_SATURATE: number;
     readonly SVG_FECOLORMATRIX_TYPE_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEColorMatrixElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEColorMatrixElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEColorMatrixElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEColorMatrixElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEColorMatrixElement: {
@@ -10389,10 +10390,10 @@ declare var SVGFEColorMatrixElement: {
 
 interface SVGFEComponentTransferElement extends SVGElement, SVGFilterPrimitiveStandardAttributes {
     readonly in1: SVGAnimatedString;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEComponentTransferElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEComponentTransferElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEComponentTransferElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEComponentTransferElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEComponentTransferElement: {
@@ -10415,10 +10416,10 @@ interface SVGFECompositeElement extends SVGElement, SVGFilterPrimitiveStandardAt
     readonly SVG_FECOMPOSITE_OPERATOR_OVER: number;
     readonly SVG_FECOMPOSITE_OPERATOR_UNKNOWN: number;
     readonly SVG_FECOMPOSITE_OPERATOR_XOR: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFECompositeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFECompositeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFECompositeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFECompositeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFECompositeElement: {
@@ -10450,10 +10451,10 @@ interface SVGFEConvolveMatrixElement extends SVGElement, SVGFilterPrimitiveStand
     readonly SVG_EDGEMODE_NONE: number;
     readonly SVG_EDGEMODE_UNKNOWN: number;
     readonly SVG_EDGEMODE_WRAP: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEConvolveMatrixElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEConvolveMatrixElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEConvolveMatrixElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEConvolveMatrixElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEConvolveMatrixElement: {
@@ -10471,10 +10472,10 @@ interface SVGFEDiffuseLightingElement extends SVGElement, SVGFilterPrimitiveStan
     readonly kernelUnitLengthX: SVGAnimatedNumber;
     readonly kernelUnitLengthY: SVGAnimatedNumber;
     readonly surfaceScale: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDiffuseLightingElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDiffuseLightingElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDiffuseLightingElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDiffuseLightingElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEDiffuseLightingElement: {
@@ -10493,10 +10494,10 @@ interface SVGFEDisplacementMapElement extends SVGElement, SVGFilterPrimitiveStan
     readonly SVG_CHANNEL_G: number;
     readonly SVG_CHANNEL_R: number;
     readonly SVG_CHANNEL_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDisplacementMapElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDisplacementMapElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDisplacementMapElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDisplacementMapElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEDisplacementMapElement: {
@@ -10512,10 +10513,10 @@ declare var SVGFEDisplacementMapElement: {
 interface SVGFEDistantLightElement extends SVGElement {
     readonly azimuth: SVGAnimatedNumber;
     readonly elevation: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDistantLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDistantLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDistantLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEDistantLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEDistantLightElement: {
@@ -10524,10 +10525,10 @@ declare var SVGFEDistantLightElement: {
 };
 
 interface SVGFEFloodElement extends SVGElement, SVGFilterPrimitiveStandardAttributes {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFloodElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFloodElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFloodElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFloodElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEFloodElement: {
@@ -10536,10 +10537,10 @@ declare var SVGFEFloodElement: {
 };
 
 interface SVGFEFuncAElement extends SVGComponentTransferFunctionElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncAElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncAElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncAElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncAElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEFuncAElement: {
@@ -10548,10 +10549,10 @@ declare var SVGFEFuncAElement: {
 };
 
 interface SVGFEFuncBElement extends SVGComponentTransferFunctionElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncBElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncBElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncBElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncBElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEFuncBElement: {
@@ -10560,10 +10561,10 @@ declare var SVGFEFuncBElement: {
 };
 
 interface SVGFEFuncGElement extends SVGComponentTransferFunctionElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEFuncGElement: {
@@ -10572,10 +10573,10 @@ declare var SVGFEFuncGElement: {
 };
 
 interface SVGFEFuncRElement extends SVGComponentTransferFunctionElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncRElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncRElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncRElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEFuncRElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEFuncRElement: {
@@ -10588,10 +10589,10 @@ interface SVGFEGaussianBlurElement extends SVGElement, SVGFilterPrimitiveStandar
     readonly stdDeviationX: SVGAnimatedNumber;
     readonly stdDeviationY: SVGAnimatedNumber;
     setStdDeviation(stdDeviationX: number, stdDeviationY: number): void;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEGaussianBlurElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEGaussianBlurElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEGaussianBlurElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEGaussianBlurElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEGaussianBlurElement: {
@@ -10601,10 +10602,10 @@ declare var SVGFEGaussianBlurElement: {
 
 interface SVGFEImageElement extends SVGElement, SVGFilterPrimitiveStandardAttributes, SVGURIReference {
     readonly preserveAspectRatio: SVGAnimatedPreserveAspectRatio;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEImageElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEImageElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEImageElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEImageElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEImageElement: {
@@ -10613,10 +10614,10 @@ declare var SVGFEImageElement: {
 };
 
 interface SVGFEMergeElement extends SVGElement, SVGFilterPrimitiveStandardAttributes {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEMergeElement: {
@@ -10626,10 +10627,10 @@ declare var SVGFEMergeElement: {
 
 interface SVGFEMergeNodeElement extends SVGElement {
     readonly in1: SVGAnimatedString;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeNodeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeNodeElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeNodeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMergeNodeElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEMergeNodeElement: {
@@ -10645,10 +10646,10 @@ interface SVGFEMorphologyElement extends SVGElement, SVGFilterPrimitiveStandardA
     readonly SVG_MORPHOLOGY_OPERATOR_DILATE: number;
     readonly SVG_MORPHOLOGY_OPERATOR_ERODE: number;
     readonly SVG_MORPHOLOGY_OPERATOR_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMorphologyElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMorphologyElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMorphologyElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEMorphologyElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEMorphologyElement: {
@@ -10663,10 +10664,10 @@ interface SVGFEOffsetElement extends SVGElement, SVGFilterPrimitiveStandardAttri
     readonly dx: SVGAnimatedNumber;
     readonly dy: SVGAnimatedNumber;
     readonly in1: SVGAnimatedString;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEOffsetElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEOffsetElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEOffsetElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEOffsetElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEOffsetElement: {
@@ -10678,10 +10679,10 @@ interface SVGFEPointLightElement extends SVGElement {
     readonly x: SVGAnimatedNumber;
     readonly y: SVGAnimatedNumber;
     readonly z: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEPointLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEPointLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEPointLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFEPointLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFEPointLightElement: {
@@ -10696,10 +10697,10 @@ interface SVGFESpecularLightingElement extends SVGElement, SVGFilterPrimitiveSta
     readonly specularConstant: SVGAnimatedNumber;
     readonly specularExponent: SVGAnimatedNumber;
     readonly surfaceScale: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpecularLightingElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpecularLightingElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpecularLightingElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpecularLightingElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFESpecularLightingElement: {
@@ -10716,10 +10717,10 @@ interface SVGFESpotLightElement extends SVGElement {
     readonly x: SVGAnimatedNumber;
     readonly y: SVGAnimatedNumber;
     readonly z: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpotLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpotLightElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpotLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFESpotLightElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFESpotLightElement: {
@@ -10729,10 +10730,10 @@ declare var SVGFESpotLightElement: {
 
 interface SVGFETileElement extends SVGElement, SVGFilterPrimitiveStandardAttributes {
     readonly in1: SVGAnimatedString;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETileElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETileElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETileElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETileElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFETileElement: {
@@ -10753,10 +10754,10 @@ interface SVGFETurbulenceElement extends SVGElement, SVGFilterPrimitiveStandardA
     readonly SVG_TURBULENCE_TYPE_FRACTALNOISE: number;
     readonly SVG_TURBULENCE_TYPE_TURBULENCE: number;
     readonly SVG_TURBULENCE_TYPE_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETurbulenceElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETurbulenceElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETurbulenceElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFETurbulenceElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFETurbulenceElement: {
@@ -10780,10 +10781,10 @@ interface SVGFilterElement extends SVGElement, SVGUnitTypes, SVGURIReference {
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
     setFilterRes(filterResX: number, filterResY: number): void;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFilterElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFilterElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFilterElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGFilterElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGFilterElement: {
@@ -10796,10 +10797,10 @@ interface SVGForeignObjectElement extends SVGGraphicsElement {
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGForeignObjectElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGForeignObjectElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGForeignObjectElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGForeignObjectElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGForeignObjectElement: {
@@ -10808,10 +10809,10 @@ declare var SVGForeignObjectElement: {
 };
 
 interface SVGGElement extends SVGGraphicsElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGGElement: {
@@ -10827,10 +10828,10 @@ interface SVGGradientElement extends SVGElement, SVGUnitTypes, SVGURIReference {
     readonly SVG_SPREADMETHOD_REFLECT: number;
     readonly SVG_SPREADMETHOD_REPEAT: number;
     readonly SVG_SPREADMETHOD_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGGradientElement: {
@@ -10850,10 +10851,10 @@ interface SVGGraphicsElement extends SVGElement, SVGTests {
     getCTM(): SVGMatrix;
     getScreenCTM(): SVGMatrix;
     getTransformToElement(element: SVGElement): SVGMatrix;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGraphicsElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGraphicsElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGraphicsElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGGraphicsElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGGraphicsElement: {
@@ -10867,10 +10868,10 @@ interface SVGImageElement extends SVGGraphicsElement, SVGURIReference {
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGImageElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGImageElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGImageElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGImageElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGImageElement: {
@@ -10935,10 +10936,10 @@ interface SVGLinearGradientElement extends SVGGradientElement {
     readonly x2: SVGAnimatedLength;
     readonly y1: SVGAnimatedLength;
     readonly y2: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLinearGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLinearGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLinearGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLinearGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGLinearGradientElement: {
@@ -10951,10 +10952,10 @@ interface SVGLineElement extends SVGGraphicsElement {
     readonly x2: SVGAnimatedLength;
     readonly y1: SVGAnimatedLength;
     readonly y2: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLineElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLineElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLineElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGLineElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGLineElement: {
@@ -10978,10 +10979,10 @@ interface SVGMarkerElement extends SVGElement, SVGFitToViewBox {
     readonly SVG_MARKERUNITS_STROKEWIDTH: number;
     readonly SVG_MARKERUNITS_UNKNOWN: number;
     readonly SVG_MARKERUNITS_USERSPACEONUSE: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMarkerElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMarkerElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMarkerElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMarkerElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGMarkerElement: {
@@ -11002,10 +11003,10 @@ interface SVGMaskElement extends SVGElement, SVGTests, SVGUnitTypes {
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMaskElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMaskElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMaskElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMaskElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGMaskElement: {
@@ -11039,10 +11040,10 @@ declare var SVGMatrix: {
 };
 
 interface SVGMetadataElement extends SVGElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMetadataElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMetadataElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMetadataElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGMetadataElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGMetadataElement: {
@@ -11099,10 +11100,10 @@ interface SVGPathElement extends SVGGraphicsElement {
     getPathSegAtLength(distance: number): number;
     getPointAtLength(distance: number): SVGPoint;
     getTotalLength(): number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGPathElement: {
@@ -11394,10 +11395,10 @@ interface SVGPatternElement extends SVGElement, SVGTests, SVGUnitTypes, SVGFitTo
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPatternElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPatternElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPatternElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPatternElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGPatternElement: {
@@ -11433,10 +11434,10 @@ declare var SVGPointList: {
 };
 
 interface SVGPolygonElement extends SVGGraphicsElement, SVGAnimatedPoints {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolygonElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolygonElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolygonElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolygonElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGPolygonElement: {
@@ -11445,10 +11446,10 @@ declare var SVGPolygonElement: {
 };
 
 interface SVGPolylineElement extends SVGGraphicsElement, SVGAnimatedPoints {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolylineElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolylineElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolylineElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGPolylineElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGPolylineElement: {
@@ -11500,10 +11501,10 @@ interface SVGRadialGradientElement extends SVGGradientElement {
     readonly fx: SVGAnimatedLength;
     readonly fy: SVGAnimatedLength;
     readonly r: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRadialGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRadialGradientElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRadialGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRadialGradientElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGRadialGradientElement: {
@@ -11530,10 +11531,10 @@ interface SVGRectElement extends SVGGraphicsElement {
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRectElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRectElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRectElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGRectElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGRectElement: {
@@ -11543,10 +11544,10 @@ declare var SVGRectElement: {
 
 interface SVGScriptElement extends SVGElement, SVGURIReference {
     type: string;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGScriptElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGScriptElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGScriptElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGScriptElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGScriptElement: {
@@ -11556,10 +11557,10 @@ declare var SVGScriptElement: {
 
 interface SVGStopElement extends SVGElement {
     readonly offset: SVGAnimatedNumber;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStopElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStopElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStopElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStopElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGStopElement: {
@@ -11588,10 +11589,10 @@ interface SVGStyleElement extends SVGElement {
     media: string;
     title: string;
     type: string;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStyleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStyleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStyleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGStyleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGStyleElement: {
@@ -11651,10 +11652,10 @@ interface SVGSVGElement extends SVGGraphicsElement, DocumentEvent, SVGFitToViewB
     unpauseAnimations(): void;
     unsuspendRedraw(suspendHandleID: number): void;
     unsuspendRedrawAll(): void;
-    addEventListener<K extends keyof SVGSVGElementEventMap>(type: K, listener: (this: SVGSVGElement, ev: SVGSVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGSVGElementEventMap>(type: K, listener: (this: SVGSVGElement, ev: SVGSVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGSVGElementEventMap>(type: K, listener: (this: SVGSVGElement, ev: SVGSVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGSVGElementEventMap>(type: K, listener: (this: SVGSVGElement, ev: SVGSVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGSVGElement: {
@@ -11663,10 +11664,10 @@ declare var SVGSVGElement: {
 };
 
 interface SVGSwitchElement extends SVGGraphicsElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSwitchElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSwitchElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSwitchElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSwitchElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGSwitchElement: {
@@ -11675,10 +11676,10 @@ declare var SVGSwitchElement: {
 };
 
 interface SVGSymbolElement extends SVGElement, SVGFitToViewBox {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSymbolElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSymbolElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSymbolElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGSymbolElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGSymbolElement: {
@@ -11701,10 +11702,10 @@ interface SVGTextContentElement extends SVGGraphicsElement {
     readonly LENGTHADJUST_SPACING: number;
     readonly LENGTHADJUST_SPACINGANDGLYPHS: number;
     readonly LENGTHADJUST_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextContentElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextContentElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextContentElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextContentElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTextContentElement: {
@@ -11716,10 +11717,10 @@ declare var SVGTextContentElement: {
 };
 
 interface SVGTextElement extends SVGTextPositioningElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTextElement: {
@@ -11737,10 +11738,10 @@ interface SVGTextPathElement extends SVGTextContentElement, SVGURIReference {
     readonly TEXTPATH_SPACINGTYPE_AUTO: number;
     readonly TEXTPATH_SPACINGTYPE_EXACT: number;
     readonly TEXTPATH_SPACINGTYPE_UNKNOWN: number;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPathElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPathElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTextPathElement: {
@@ -11760,10 +11761,10 @@ interface SVGTextPositioningElement extends SVGTextContentElement {
     readonly rotate: SVGAnimatedNumberList;
     readonly x: SVGAnimatedLengthList;
     readonly y: SVGAnimatedLengthList;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPositioningElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPositioningElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPositioningElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTextPositioningElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTextPositioningElement: {
@@ -11772,10 +11773,10 @@ declare var SVGTextPositioningElement: {
 };
 
 interface SVGTitleElement extends SVGElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTitleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTitleElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTitleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTitleElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTitleElement: {
@@ -11833,10 +11834,10 @@ declare var SVGTransformList: {
 };
 
 interface SVGTSpanElement extends SVGTextPositioningElement {
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTSpanElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTSpanElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTSpanElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGTSpanElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGTSpanElement: {
@@ -11858,10 +11859,10 @@ interface SVGUseElement extends SVGGraphicsElement, SVGURIReference {
     readonly width: SVGAnimatedLength;
     readonly x: SVGAnimatedLength;
     readonly y: SVGAnimatedLength;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGUseElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGUseElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGUseElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGUseElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGUseElement: {
@@ -11871,10 +11872,10 @@ declare var SVGUseElement: {
 
 interface SVGViewElement extends SVGElement, SVGZoomAndPan, SVGFitToViewBox {
     readonly viewTarget: SVGStringList;
-    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGViewElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGViewElement, ev: SVGElementEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGViewElement, ev: SVGElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof SVGElementEventMap>(type: K, listener: (this: SVGViewElement, ev: SVGElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var SVGViewElement: {
@@ -11994,10 +11995,10 @@ interface TextTrack extends EventTarget {
     readonly LOADING: number;
     readonly NONE: number;
     readonly SHOWING: number;
-    addEventListener<K extends keyof TextTrackEventMap>(type: K, listener: (this: TextTrack, ev: TextTrackEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof TextTrackEventMap>(type: K, listener: (this: TextTrack, ev: TextTrackEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof TextTrackEventMap>(type: K, listener: (this: TextTrack, ev: TextTrackEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof TextTrackEventMap>(type: K, listener: (this: TextTrack, ev: TextTrackEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var TextTrack: {
@@ -12027,10 +12028,10 @@ interface TextTrackCue extends EventTarget {
     text: string;
     readonly track: TextTrack;
     getCueAsHTML(): DocumentFragment;
-    addEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: TextTrackCue, ev: TextTrackCueEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: TextTrackCue, ev: TextTrackCueEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: TextTrackCue, ev: TextTrackCueEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof TextTrackCueEventMap>(type: K, listener: (this: TextTrackCue, ev: TextTrackCueEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var TextTrackCue: {
@@ -12058,10 +12059,10 @@ interface TextTrackList extends EventTarget {
     readonly length: number;
     onaddtrack: ((this: TextTrackList, ev: TrackEvent) => any) | null;
     item(index: number): TextTrack;
-    addEventListener<K extends keyof TextTrackListEventMap>(type: K, listener: (this: TextTrackList, ev: TextTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof TextTrackListEventMap>(type: K, listener: (this: TextTrackList, ev: TextTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof TextTrackListEventMap>(type: K, listener: (this: TextTrackList, ev: TextTrackListEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof TextTrackListEventMap>(type: K, listener: (this: TextTrackList, ev: TextTrackListEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [index: number]: TextTrack;
 }
 
@@ -12269,10 +12270,10 @@ interface VideoTrackList extends EventTarget {
     readonly selectedIndex: number;
     getTrackById(id: string): VideoTrack | null;
     item(index: number): VideoTrack;
-    addEventListener<K extends keyof VideoTrackListEventMap>(type: K, listener: (this: VideoTrackList, ev: VideoTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof VideoTrackListEventMap>(type: K, listener: (this: VideoTrackList, ev: VideoTrackListEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof VideoTrackListEventMap>(type: K, listener: (this: VideoTrackList, ev: VideoTrackListEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof VideoTrackListEventMap>(type: K, listener: (this: VideoTrackList, ev: VideoTrackListEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [index: number]: VideoTrack;
 }
 
@@ -13290,10 +13291,10 @@ declare var WebKitPoint: {
 };
 
 interface webkitRTCPeerConnection extends RTCPeerConnection {
-    addEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: webkitRTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: webkitRTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: webkitRTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof RTCPeerConnectionEventMap>(type: K, listener: (this: webkitRTCPeerConnection, ev: RTCPeerConnectionEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var webkitRTCPeerConnection: {
@@ -13325,10 +13326,10 @@ interface WebSocket extends EventTarget {
     readonly CLOSING: number;
     readonly CONNECTING: number;
     readonly OPEN: number;
-    addEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var WebSocket: {
@@ -13640,10 +13641,10 @@ interface Window extends EventTarget, WindowTimers, WindowSessionStorage, Window
     scroll(options?: ScrollToOptions): void;
     scrollTo(options?: ScrollToOptions): void;
     scrollBy(options?: ScrollToOptions): void;
-    addEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Window: {
@@ -13659,10 +13660,10 @@ interface Worker extends EventTarget, AbstractWorker {
     onmessage: (this: Worker, ev: MessageEvent) => any;
     postMessage(message: any, transfer?: any[]): void;
     terminate(): void;
-    addEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Worker: {
@@ -13671,10 +13672,10 @@ declare var Worker: {
 };
 
 interface XMLDocument extends Document {
-    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: XMLDocument, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: XMLDocument, ev: DocumentEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: XMLDocument, ev: DocumentEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof DocumentEventMap>(type: K, listener: (this: XMLDocument, ev: DocumentEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var XMLDocument: {
@@ -13715,10 +13716,10 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly LOADING: number;
     readonly OPENED: number;
     readonly UNSENT: number;
-    addEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var XMLHttpRequest: {
@@ -13732,10 +13733,10 @@ declare var XMLHttpRequest: {
 };
 
 interface XMLHttpRequestUpload extends EventTarget, XMLHttpRequestEventTarget {
-    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var XMLHttpRequestUpload: {
@@ -13840,10 +13841,10 @@ interface AbstractWorkerEventMap {
 
 interface AbstractWorker {
     onerror: (this: AbstractWorker, ev: ErrorEvent) => any;
-    addEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface Body {
@@ -13988,10 +13989,10 @@ interface GlobalEventHandlers {
     onpointerover: (this: GlobalEventHandlers, ev: PointerEvent) => any;
     onpointerup: (this: GlobalEventHandlers, ev: PointerEvent) => any;
     onwheel: (this: GlobalEventHandlers, ev: WheelEvent) => any;
-    addEventListener<K extends keyof GlobalEventHandlersEventMap>(type: K, listener: (this: GlobalEventHandlers, ev: GlobalEventHandlersEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof GlobalEventHandlersEventMap>(type: K, listener: (this: GlobalEventHandlers, ev: GlobalEventHandlersEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof GlobalEventHandlersEventMap>(type: K, listener: (this: GlobalEventHandlers, ev: GlobalEventHandlersEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof GlobalEventHandlersEventMap>(type: K, listener: (this: GlobalEventHandlers, ev: GlobalEventHandlersEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface GlobalFetch {
@@ -14043,10 +14044,10 @@ interface MSBaseReader {
     readonly DONE: number;
     readonly EMPTY: number;
     readonly LOADING: number;
-    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface MSFileSaver {
@@ -14192,10 +14193,10 @@ interface XMLHttpRequestEventTarget {
     onloadstart: (this: XMLHttpRequest, ev: Event) => any;
     onprogress: (this: XMLHttpRequest, ev: ProgressEvent) => any;
     ontimeout: (this: XMLHttpRequest, ev: ProgressEvent) => any;
-    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface BroadcastChannel extends EventTarget {
@@ -14204,8 +14205,10 @@ interface BroadcastChannel extends EventTarget {
     onmessageerror: (ev: MessageEvent) => any;
     close(): void;
     postMessage(message: any): void;
-    addEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var BroadcastChannel: {
@@ -15085,10 +15088,10 @@ declare var indexedDB: IDBFactory;
 declare function atob(encodedString: string): string;
 declare function btoa(rawString: string): string;
 declare function fetch(input: RequestInfo, init?: RequestInit): Promise<Response>;
-declare function addEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, useCapture?: boolean): void;
-declare function addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-declare function removeEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, useCapture?: boolean): void;
-declare function removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+declare function addEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+declare function addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+declare function removeEventListener<K extends keyof WindowEventMap>(type: K, listener: (this: Window, ev: WindowEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+declare function removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 type AAGUID = string;
 type AlgorithmIdentifier = string | Algorithm;
 type BodyInit = any;
@@ -15112,7 +15115,6 @@ type GLsizeiptr = number;
 type GLubyte = number;
 type GLuint = number;
 type GLushort = number;
-type HeadersInit = Headers | string[][];
 type IDBKeyPath = string;
 type KeyFormat = string;
 type KeyType = string;
@@ -15133,6 +15135,7 @@ type MouseWheelEvent = WheelEvent;
 type ScrollRestoration = "auto" | "manual";
 type FormDataEntryValue = string | File;
 type InsertPosition = "beforebegin" | "afterbegin" | "beforeend" | "afterend";
+type HeadersInit = Headers | string[][] | { [key: string]: string };
 type AppendMode = "segments" | "sequence";
 type AudioContextState = "suspended" | "running" | "closed";
 type BiquadFilterType = "lowpass" | "highpass" | "bandpass" | "lowshelf" | "highshelf" | "peaking" | "notch" | "allpass";
diff --git a/src/lib/dom.iterable.d.ts b/src/lib/dom.iterable.d.ts
index e89a22f2c14..6ca728444f2 100644
--- a/src/lib/dom.iterable.d.ts
+++ b/src/lib/dom.iterable.d.ts
@@ -4,23 +4,6 @@ interface DOMTokenList {
     [Symbol.iterator](): IterableIterator<string>;
 }
 
-interface FormData {
-    /**
-     * Returns an array of key, value pairs for every entry in the list
-     */
-    entries(): IterableIterator<[string, string | File]>;
-    /**
-     * Returns a list of keys in the list
-     */
-    keys(): IterableIterator<string>;
-    /**
-     * Returns a list of values in the list
-     */
-    values(): IterableIterator<string | File>;
-
-    [Symbol.iterator](): IterableIterator<string | File>;
-}
-
 interface Headers {
     [Symbol.iterator](): IterableIterator<[string, string]>;
     /**
@@ -87,6 +70,31 @@ interface NodeListOf<TNode extends Node> {
     [Symbol.iterator](): IterableIterator<TNode>;
 }
 
+interface HTMLCollectionBase {
+    [Symbol.iterator](): IterableIterator<Element>;
+}
+
+interface HTMLCollectionOf<T extends Element> {
+    [Symbol.iterator](): IterableIterator<T>;
+}
+
+interface FormData {
+    /**
+     * Returns an array of key, value pairs for every entry in the list
+     */
+    entries(): IterableIterator<[string, string | File]>;
+    /**
+     * Returns a list of keys in the list
+     */
+    keys(): IterableIterator<string>;
+    /**
+     * Returns a list of values in the list
+     */
+    values(): IterableIterator<string | File>;
+
+    [Symbol.iterator](): IterableIterator<string | File>;
+}
+
 interface URLSearchParams {
     /**
      * Returns an array of key, value pairs for every entry in the search params
diff --git a/src/lib/es2015.core.d.ts b/src/lib/es2015.core.d.ts
index 9ea773e3eef..ccff68968f1 100644
--- a/src/lib/es2015.core.d.ts
+++ b/src/lib/es2015.core.d.ts
@@ -50,10 +50,16 @@ interface ArrayConstructor {
     /**
      * Creates an array from an array-like object.
      * @param arrayLike An array-like object to convert to an array.
+     */
+    from<T>(arrayLike: ArrayLike<T>): T[];
+
+    /**
+     * Creates an array from an iterable object.
+     * @param arrayLike An array-like object to convert to an array.
      * @param mapfn A mapping function to call on every element of the array.
      * @param thisArg Value of 'this' used to invoke the mapfn.
      */
-    from<T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[];
+    from<T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[];
 
     /**
      * Returns a new array from a set of elements.
@@ -443,7 +449,7 @@ interface String {
 
     /**
      * Returns a String value that is made from count copies appended together. If count is 0,
-     * T is the empty String is returned.
+     * the empty string is returned.
      * @param count number of copies to append
      */
     repeat(count: number): string;
diff --git a/src/lib/es2015.iterable.d.ts b/src/lib/es2015.iterable.d.ts
index 7b84c3e04c4..f3024bc334f 100644
--- a/src/lib/es2015.iterable.d.ts
+++ b/src/lib/es2015.iterable.d.ts
@@ -48,13 +48,19 @@ interface Array<T> {
 }
 
 interface ArrayConstructor {
+    /**
+     * Creates an array from an iterable object.
+     * @param iterable An iterable object to convert to an array.
+     */
+    from<T>(iterable: Iterable<T>): T[];
+
     /**
      * Creates an array from an iterable object.
      * @param iterable An iterable object to convert to an array.
      * @param mapfn A mapping function to call on every element of the array.
      * @param thisArg Value of 'this' used to invoke the mapfn.
      */
-    from<T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[];
+    from<T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[];
 }
 
 interface ReadonlyArray<T> {
diff --git a/src/lib/es2015.symbol.wellknown.d.ts b/src/lib/es2015.symbol.wellknown.d.ts
index 268570ff232..23d836c6515 100644
--- a/src/lib/es2015.symbol.wellknown.d.ts
+++ b/src/lib/es2015.symbol.wellknown.d.ts
@@ -150,7 +150,7 @@ interface Promise<T> {
 }
 
 interface PromiseConstructor {
-    readonly [Symbol.species]: Function;
+    readonly [Symbol.species]: PromiseConstructor;
 }
 
 interface RegExp {
@@ -202,7 +202,7 @@ interface RegExp {
 }
 
 interface RegExpConstructor {
-    [Symbol.species](): RegExpConstructor;
+    readonly [Symbol.species]: RegExpConstructor;
 }
 
 interface String {
@@ -283,3 +283,16 @@ interface Float32Array {
 interface Float64Array {
     readonly [Symbol.toStringTag]: "Float64Array";
 }
+
+interface ArrayConstructor {
+    readonly [Symbol.species]: ArrayConstructor;
+}
+interface MapConstructor {
+    readonly [Symbol.species]: MapConstructor;
+}
+interface SetConstructor {
+    readonly [Symbol.species]: SetConstructor;
+}
+interface ArrayBufferConstructor {
+    readonly [Symbol.species]: ArrayBufferConstructor;
+}
\ No newline at end of file
diff --git a/src/lib/es2017.d.ts b/src/lib/es2017.d.ts
index 80282355a45..87aa273140b 100644
--- a/src/lib/es2017.d.ts
+++ b/src/lib/es2017.d.ts
@@ -3,3 +3,4 @@
 /// <reference path="lib.es2017.sharedmemory.d.ts" />
 /// <reference path="lib.es2017.string.d.ts" />
 /// <reference path="lib.es2017.intl.d.ts" />
+/// <reference path="lib.es2017.typedarrays.d.ts" />
diff --git a/src/lib/es2017.typedarrays.d.ts b/src/lib/es2017.typedarrays.d.ts
new file mode 100644
index 00000000000..a0b64135a30
--- /dev/null
+++ b/src/lib/es2017.typedarrays.d.ts
@@ -0,0 +1,35 @@
+interface Int8ArrayConstructor {
+    new (): Int8Array;
+}
+
+interface Uint8ArrayConstructor {
+    new (): Uint8Array;
+}
+
+interface Uint8ClampedArrayConstructor {
+    new (): Uint8ClampedArray;
+}
+
+interface Int16ArrayConstructor {
+    new (): Int16Array;
+}
+
+interface Uint16ArrayConstructor {
+    new (): Uint16Array;
+}
+
+interface Int32ArrayConstructor {
+    new (): Int32Array;
+}
+
+interface Uint32ArrayConstructor {
+    new (): Uint32Array;
+}
+
+interface Float32ArrayConstructor {
+    new (): Float32Array;
+}
+
+interface Float64ArrayConstructor {
+    new (): Float64Array;
+}
diff --git a/src/lib/webworker.generated.d.ts b/src/lib/webworker.generated.d.ts
index 2651d1664ff..6eb17c33c5e 100644
--- a/src/lib/webworker.generated.d.ts
+++ b/src/lib/webworker.generated.d.ts
@@ -37,7 +37,7 @@ interface IDBIndexParameters {
 
 interface IDBObjectStoreParameters {
     autoIncrement?: boolean;
-    keyPath?: IDBKeyPath | null;
+    keyPath?: string | string[];
 }
 
 interface KeyAlgorithm {
@@ -74,7 +74,7 @@ interface RequestInit {
     body?: any;
     cache?: RequestCache;
     credentials?: RequestCredentials;
-    headers?: Headers | string[][];
+    headers?: HeadersInit;
     integrity?: string;
     keepalive?: boolean;
     method?: string;
@@ -86,7 +86,7 @@ interface RequestInit {
 }
 
 interface ResponseInit {
-    headers?: Headers | string[][];
+    headers?: HeadersInit;
     status?: number;
     statusText?: string;
 }
@@ -441,10 +441,10 @@ interface FileReader extends EventTarget, MSBaseReader {
     readAsBinaryString(blob: Blob): void;
     readAsDataURL(blob: Blob): void;
     readAsText(blob: Blob, encoding?: string): void;
-    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: FileReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var FileReader: {
@@ -472,7 +472,7 @@ interface Headers {
 
 declare var Headers: {
     prototype: Headers;
-    new(init?: Headers | string[][] | object): Headers;
+    new(init?: HeadersInit): Headers;
 };
 
 interface IDBCursor {
@@ -524,11 +524,12 @@ interface IDBDatabase extends EventTarget {
     createObjectStore(name: string, optionalParameters?: IDBObjectStoreParameters): IDBObjectStore;
     deleteObjectStore(name: string): void;
     transaction(storeNames: string | string[], mode?: IDBTransactionMode): IDBTransaction;
-    addEventListener(type: "versionchange", listener: (ev: IDBVersionChangeEvent) => any, useCapture?: boolean): void;
-    addEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener(type: "versionchange", listener: (this: IDBDatabase, ev: IDBVersionChangeEvent) => any, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener(type: "versionchange", listener: (this: IDBDatabase, ev: IDBVersionChangeEvent) => any, options?: boolean | EventListenerOptions): void;
+    addEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBDatabaseEventMap>(type: K, listener: (this: IDBDatabase, ev: IDBDatabaseEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBDatabase: {
@@ -612,10 +613,10 @@ interface IDBOpenDBRequestEventMap extends IDBRequestEventMap {
 interface IDBOpenDBRequest extends IDBRequest {
     onblocked: (this: IDBOpenDBRequest, ev: Event) => any;
     onupgradeneeded: (this: IDBOpenDBRequest, ev: IDBVersionChangeEvent) => any;
-    addEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBOpenDBRequestEventMap>(type: K, listener: (this: IDBOpenDBRequest, ev: IDBOpenDBRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBOpenDBRequest: {
@@ -636,10 +637,10 @@ interface IDBRequest extends EventTarget {
     readonly result: any;
     source: IDBObjectStore | IDBIndex | IDBCursor;
     readonly transaction: IDBTransaction;
-    addEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBRequestEventMap>(type: K, listener: (this: IDBRequest, ev: IDBRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBRequest: {
@@ -665,10 +666,10 @@ interface IDBTransaction extends EventTarget {
     readonly READ_ONLY: string;
     readonly READ_WRITE: string;
     readonly VERSION_CHANGE: string;
-    addEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof IDBTransactionEventMap>(type: K, listener: (this: IDBTransaction, ev: IDBTransactionEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var IDBTransaction: {
@@ -733,10 +734,10 @@ interface MessagePort extends EventTarget {
     close(): void;
     postMessage(message?: any, transfer?: any[]): void;
     start(): void;
-    addEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MessagePortEventMap>(type: K, listener: (this: MessagePort, ev: MessagePortEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var MessagePort: {
@@ -764,10 +765,10 @@ interface Notification extends EventTarget {
     readonly tag: string;
     readonly title: string;
     close(): void;
-    addEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof NotificationEventMap>(type: K, listener: (this: Notification, ev: NotificationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Notification: {
@@ -994,10 +995,10 @@ interface ServiceWorker extends EventTarget, AbstractWorker {
     readonly scriptURL: USVString;
     readonly state: ServiceWorkerState;
     postMessage(message: any, transfer?: any[]): void;
-    addEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerEventMap>(type: K, listener: (this: ServiceWorker, ev: ServiceWorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorker: {
@@ -1021,10 +1022,10 @@ interface ServiceWorkerRegistration extends EventTarget {
     showNotification(title: string, options?: NotificationOptions): Promise<void>;
     unregister(): Promise<boolean>;
     update(): Promise<void>;
-    addEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerRegistrationEventMap>(type: K, listener: (this: ServiceWorkerRegistration, ev: ServiceWorkerRegistrationEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorkerRegistration: {
@@ -1089,10 +1090,10 @@ interface WebSocket extends EventTarget {
     readonly CLOSING: number;
     readonly CONNECTING: number;
     readonly OPEN: number;
-    addEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var WebSocket: {
@@ -1112,10 +1113,10 @@ interface Worker extends EventTarget, AbstractWorker {
     onmessage: (this: Worker, ev: MessageEvent) => any;
     postMessage(message: any, transfer?: any[]): void;
     terminate(): void;
-    addEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WorkerEventMap>(type: K, listener: (this: Worker, ev: WorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var Worker: {
@@ -1155,10 +1156,10 @@ interface XMLHttpRequest extends EventTarget, XMLHttpRequestEventTarget {
     readonly LOADING: number;
     readonly OPENED: number;
     readonly UNSENT: number;
-    addEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventMap>(type: K, listener: (this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var XMLHttpRequest: {
@@ -1172,10 +1173,10 @@ declare var XMLHttpRequest: {
 };
 
 interface XMLHttpRequestUpload extends EventTarget, XMLHttpRequestEventTarget {
-    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestUpload, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var XMLHttpRequestUpload: {
@@ -1189,10 +1190,10 @@ interface AbstractWorkerEventMap {
 
 interface AbstractWorker {
     onerror: (this: AbstractWorker, ev: ErrorEvent) => any;
-    addEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof AbstractWorkerEventMap>(type: K, listener: (this: AbstractWorker, ev: AbstractWorkerEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface Body {
@@ -1229,10 +1230,10 @@ interface MSBaseReader {
     readonly DONE: number;
     readonly EMPTY: number;
     readonly LOADING: number;
-    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof MSBaseReaderEventMap>(type: K, listener: (this: MSBaseReader, ev: MSBaseReaderEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface NavigatorBeacon {
@@ -1286,10 +1287,10 @@ interface XMLHttpRequestEventTarget {
     onloadstart: (this: XMLHttpRequest, ev: Event) => any;
     onprogress: (this: XMLHttpRequest, ev: ProgressEvent) => any;
     ontimeout: (this: XMLHttpRequest, ev: ProgressEvent) => any;
-    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof XMLHttpRequestEventTargetEventMap>(type: K, listener: (this: XMLHttpRequestEventTarget, ev: XMLHttpRequestEventTargetEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 interface Client {
@@ -1324,10 +1325,10 @@ interface DedicatedWorkerGlobalScope extends WorkerGlobalScope {
     onmessage: (this: DedicatedWorkerGlobalScope, ev: MessageEvent) => any;
     close(): void;
     postMessage(message: any, transfer?: any[]): void;
-    addEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var DedicatedWorkerGlobalScope: {
@@ -1437,10 +1438,10 @@ interface ServiceWorkerGlobalScope extends WorkerGlobalScope {
     onsync: (this: ServiceWorkerGlobalScope, ev: SyncEvent) => any;
     readonly registration: ServiceWorkerRegistration;
     skipWaiting(): Promise<void>;
-    addEventListener<K extends keyof ServiceWorkerGlobalScopeEventMap>(type: K, listener: (this: ServiceWorkerGlobalScope, ev: ServiceWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof ServiceWorkerGlobalScopeEventMap>(type: K, listener: (this: ServiceWorkerGlobalScope, ev: ServiceWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof ServiceWorkerGlobalScopeEventMap>(type: K, listener: (this: ServiceWorkerGlobalScope, ev: ServiceWorkerGlobalScopeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof ServiceWorkerGlobalScopeEventMap>(type: K, listener: (this: ServiceWorkerGlobalScope, ev: ServiceWorkerGlobalScopeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var ServiceWorkerGlobalScope: {
@@ -1484,10 +1485,10 @@ interface WorkerGlobalScope extends EventTarget, WorkerUtils, WindowConsole, Glo
     msWriteProfilerMark(profilerMarkName: string): void;
     createImageBitmap(image: ImageBitmap | ImageData | Blob, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     createImageBitmap(image: ImageBitmap | ImageData | Blob, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
-    addEventListener<K extends keyof WorkerGlobalScopeEventMap>(type: K, listener: (this: WorkerGlobalScope, ev: WorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-    removeEventListener<K extends keyof WorkerGlobalScopeEventMap>(type: K, listener: (this: WorkerGlobalScope, ev: WorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof WorkerGlobalScopeEventMap>(type: K, listener: (this: WorkerGlobalScope, ev: WorkerGlobalScopeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof WorkerGlobalScopeEventMap>(type: K, listener: (this: WorkerGlobalScope, ev: WorkerGlobalScopeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var WorkerGlobalScope: {
@@ -1544,8 +1545,10 @@ interface BroadcastChannel extends EventTarget {
     onmessageerror: (ev: MessageEvent) => any;
     close(): void;
     postMessage(message: any): void;
-    addEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, useCapture?: boolean): void;
-    addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+    addEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+    addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+    removeEventListener<K extends keyof BroadcastChannelEventMap>(type: K, listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+    removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 }
 
 declare var BroadcastChannel: {
@@ -1875,10 +1878,10 @@ declare function btoa(rawString: string): string;
 declare var console: Console;
 declare function fetch(input: RequestInfo, init?: RequestInit): Promise<Response>;
 declare function dispatchEvent(evt: Event): boolean;
-declare function addEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-declare function addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
-declare function removeEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, useCapture?: boolean): void;
-declare function removeEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
+declare function addEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
+declare function addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
+declare function removeEventListener<K extends keyof DedicatedWorkerGlobalScopeEventMap>(type: K, listener: (this: DedicatedWorkerGlobalScope, ev: DedicatedWorkerGlobalScopeEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
+declare function removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
 type AlgorithmIdentifier = string | Algorithm;
 type BodyInit = any;
 type IDBKeyPath = string;
@@ -1887,6 +1890,7 @@ type USVString = string;
 type IDBValidKey = number | string | Date | IDBArrayKey;
 type BufferSource = ArrayBuffer | ArrayBufferView;
 type FormDataEntryValue = string | File;
+type HeadersInit = Headers | string[][] | { [key: string]: string };
 type IDBCursorDirection = "next" | "nextunique" | "prev" | "prevunique";
 type IDBRequestReadyState = "pending" | "done";
 type IDBTransactionMode = "readonly" | "readwrite" | "versionchange";
diff --git a/src/loc/lcl/chs/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/chs/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 94bbc474495..c59e9c20060 100644
--- a/src/loc/lcl/chs/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/chs/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2241,6 +2241,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[转换为默认导入]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2970,6 +2979,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[预期的 JSX 片段的相应结束标记。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4212,6 +4230,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 片段没有相应的结束标记。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[使用 --jsxFactory 时不支持 JSX 片段]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/cht/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/cht/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 3ea6148617a..929b7edf058 100644
--- a/src/loc/lcl/cht/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/cht/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2241,6 +2241,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[轉換為預設匯入]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2970,6 +2979,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 片段必須有對應的結尾標記。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4212,6 +4230,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 片段沒有對應的結尾標記。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[使用 --jsxFactory 時，不支援 JSX 片段]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/csy/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/csy/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 078b17179a4..8dab90a1ba2 100644
--- a/src/loc/lcl/csy/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/csy/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2250,6 +2250,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Převést na výchozí import]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2979,6 +2988,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Pro fragment JSX se očekávala odpovídající uzavírací značka.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4221,6 +4239,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Fragment JSX nemá odpovídající uzavírací značku.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Při použití --jsxFactory se nepodporuje fragment JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -8320,7 +8356,7 @@
         <Str Cat="Text">
           <Val><![CDATA['get' and 'set' accessor must have the same type.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Přístupový  objekt get a set musí obsahovat stejný typ.]]></Val>
+            <Val><![CDATA[Přístupový objekt get a set musí obsahovat stejný typ.]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/deu/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/deu/diagnosticMessages/diagnosticMessages.generated.json.lcl
index d10f7077dc5..c00e5a2a2e7 100644
--- a/src/loc/lcl/deu/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/deu/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -827,10 +827,13 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA["{0}" zur vorhandenen Importdeklaration aus "{1}" hinzufügen.]]></Val>
+            <Val><![CDATA[Fügen Sie "{0}" zur vorhandenen Importdeklaration aus "{1}" hinzu.]]></Val>
           </Tgt>
+          <Prev Cat="Text">
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          </Prev>
         </Str>
         <Disp Icon="Str" />
       </Item>
@@ -2229,6 +2232,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[In Standardimport konvertieren]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2886,6 +2898,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[{0}-{1} Typargumente erwartet; geben Sie diese mit einem @extends-Tag an.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2913,6 +2934,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[{0} Typargumente erwartet; geben Sie diese mit einem @extends-Tag an.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2940,6 +2970,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Für das JSX-Fragment wurde das entsprechende schließende Tag erwartet.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3163,7 +3202,7 @@
         <Str Cat="Text">
           <Val><![CDATA[Extract to {0} in {1}]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Nach {0} in {1} extrahieren]]></Val>
+            <Val><![CDATA[Als {0} nach {1} extrahieren]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
@@ -3172,7 +3211,7 @@
         <Str Cat="Text">
           <Val><![CDATA[Extract to {0} in {1} scope]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Nach {0} in {1}-Bereich extrahieren]]></Val>
+            <Val><![CDATA[Als {0} in {1}-Bereich extrahieren]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
@@ -3181,7 +3220,7 @@
         <Str Cat="Text">
           <Val><![CDATA[Extract to {0} in enclosing scope]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Nach {0} in einschließenden Bereich extrahieren]]></Val>
+            <Val><![CDATA[Als {0} in einschließenden Bereich extrahieren]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
@@ -3665,10 +3704,13 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA["{0}" aus "{1}" importieren.]]></Val>
+            <Val><![CDATA[Importieren Sie "{0}" aus "{1}".]]></Val>
           </Tgt>
+          <Prev Cat="Text">
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
+          </Prev>
         </Str>
         <Disp Icon="Str" />
       </Item>
@@ -4176,6 +4218,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Das JSX-Fragment weist kein entsprechendes schließendes Tag auf.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Das JSX-Fragment wird bei Verwendung von --jsxFactory nicht unterstützt.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6339,11 +6399,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Nachfolgende Variablendeklarationen müssen den gleichen Typ aufweisen. Die Variable "{0}" muss den Typ "{1}" aufweisen, ist hier aber vom Typ "{2}".]]></Val>
+            <Val><![CDATA[Nachfolgende Variablendeklarationen müssen den gleichen Typ aufweisen. Die Variable "{0}" muss bei "{2}" den Typ "{1}" aufweisen, ist hier aber vom Typ "{3}".]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/esn/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/esn/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 06f8e9220bc..4865cf6c508 100644
--- a/src/loc/lcl/esn/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/esn/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -839,12 +839,12 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Agrega {0} a una declaración de importación existente desde {1}.]]></Val>
+            <Val><![CDATA[Agregue "{0}" a una declaración de importación existente desde "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Add {0} to existing import declaration from {1}]]></Val>
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -2250,6 +2250,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Convertir en importación predeterminada]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2907,6 +2916,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Se esperaban argumentos de tipo {0}-{1}; proporciónelos con una etiqueta "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2934,6 +2952,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Se esperaban argumentos de tipo {0}; proporciónelos con una etiqueta "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2961,6 +2988,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Se esperaba la etiqueta de cierre correspondiente para el fragmento de JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3689,12 +3725,12 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Importa {0} desde {1}.]]></Val>
+            <Val><![CDATA[Importe "{0}" desde "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Import {0} from {1}]]></Val>
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -4203,6 +4239,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[El fragmento de JSX no tiene la etiqueta de cierre correspondiente.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[El fragmento de JSX no es compatible cuando se utiliza --jsxFactory]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6375,11 +6429,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Las declaraciones de variable subsiguientes deben tener el mismo tipo. La variable '{0}' debe ser de tipo '{1}', pero aquí tiene el tipo '{2}'.]]></Val>
+            <Val><![CDATA[Las declaraciones de variable subsiguientes deben tener el mismo tipo. La variable "{0}" tiene el tipo "{1}" en {2}, pero aquí tiene el tipo "{3}".]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/fra/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/fra/diagnosticMessages/diagnosticMessages.generated.json.lcl
index c23ea7cc378..2bf61430d60 100644
--- a/src/loc/lcl/fra/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/fra/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -839,12 +839,12 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Ajoutez {0} à une déclaration d'importation existante à partir de {1}.]]></Val>
+            <Val><![CDATA[Ajoutez '{0}' à une déclaration d'importation existante à partir de "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Add {0} to existing import declaration from {1}]]></Val>
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -2250,6 +2250,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Convertir en importation par défaut]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2907,6 +2916,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Arguments de type {0}-{1} attendus ; indiquez-les avec la balise '@extends'.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2934,6 +2952,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Arguments de type {0} attendus ; indiquez-les avec la balise '@extends'.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2961,6 +2988,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Balise de fermeture correspondante attendue pour le fragment JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3689,12 +3725,12 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Importez {0} à partir de {1}.]]></Val>
+            <Val><![CDATA[Importez '{0}' à partir de "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Import {0} from {1}]]></Val>
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -4203,6 +4239,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Le fragment JSX n'a pas de balise de fermeture correspondante.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Le fragment JSX n'est pas pris en charge quand --jsxFactory est utilisé]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6375,11 +6429,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Les déclarations de variable ultérieures doivent avoir le même type. La variable '{0}' doit être de type '{1}', mais elle a ici le type '{2}'.]]></Val>
+            <Val><![CDATA[Les déclarations de variables ultérieures doivent avoir le même type.  La variable '{0}' a le type '{1}' au niveau de {2}, mais ici elle a le type '{3}'.]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/ita/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/ita/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 83a8d7cace7..31f3bfdefd5 100644
--- a/src/loc/lcl/ita/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/ita/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2241,6 +2241,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Converti nell'importazione predefinita]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2970,6 +2979,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[È previsto il tag di chiusura corrispondente per il frammento JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4212,6 +4230,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Per il frammento JSX non esiste alcun tag di chiusura corrispondente.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Il frammento JSX non è supportato quando si usa --jsxFactory]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/jpn/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/jpn/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 34a98237a2a..b2ae023f5a4 100644
--- a/src/loc/lcl/jpn/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/jpn/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2241,6 +2241,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[既定のインポートに変換する]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2970,6 +2979,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX フラグメントの対応する終了タグが必要です。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4212,6 +4230,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX フラグメントには対応する終了タグがありません。]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[--jsxFactory を使う場合、JSX フラグメントはサポートされません]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/kor/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/kor/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 2653d211440..2693d7cce27 100644
--- a/src/loc/lcl/kor/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/kor/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2241,6 +2241,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[기본 가져오기로 변환]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2970,6 +2979,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 조각에 닫는 태그가 필요합니다.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4212,6 +4230,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 조각에 닫는 태그가 없습니다.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX 조각은 --jsxFactory를 사용하는 경우 지원되지 않습니다.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/plk/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/plk/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 3b132575e58..b9d115872b6 100644
--- a/src/loc/lcl/plk/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/plk/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -2225,6 +2225,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Konwertuj na import domyślny]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2954,6 +2963,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Oczekiwano odpowiedniego tagu zamykającego dla fragmentu kodu JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -4193,6 +4211,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Fragment kodu JSX nie ma odpowiedniego tagu zamykającego.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[W przypadku korzystania z opcji --jsxFactory fragment kodu JSX nie jest obsługiwany]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
diff --git a/src/loc/lcl/ptb/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/ptb/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 014ca9ef8f6..1e480ff2a08 100644
--- a/src/loc/lcl/ptb/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/ptb/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -820,10 +820,13 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Adicionar {0} à declaração de importação existente de {1}.]]></Val>
+            <Val><![CDATA[Adicione "{0}" à declaração de importação existente de "{1}".]]></Val>
           </Tgt>
+          <Prev Cat="Text">
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          </Prev>
         </Str>
         <Disp Icon="Str" />
       </Item>
@@ -2222,6 +2225,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Converter para importação padrão]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2879,6 +2891,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Espera-se {0}-{1} argumentos de tipo; forneça esses recursos com uma marca "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2906,6 +2927,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Espera-se {0} argumentos de tipo; forneça esses recursos com uma marca "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2933,6 +2963,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Marca de fechamento correspondente esperada para fragmento JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3658,10 +3697,13 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Importar {0} de {1}.]]></Val>
+            <Val><![CDATA[Importar "{0}" de "{1}".]]></Val>
           </Tgt>
+          <Prev Cat="Text">
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
+          </Prev>
         </Str>
         <Disp Icon="Str" />
       </Item>
@@ -4169,6 +4211,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[O fragmento JSX não tem uma marcação de fechamento correspondente.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[O fragmento JSX não é compatível com o uso de --jsxFactory]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6332,11 +6392,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Declarações de variável subsequentes devem ter o mesmo tipo. A variável '{0}' deve ser do tipo '{1}', mas aqui tem o tipo '{2}'.]]></Val>
+            <Val><![CDATA[Declarações de variável subsequentes devem ter o mesmo tipo. A variável "{0}" deve ser do tipo "{1}" em {2}, mas aqui tem o tipo "{3}".]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/rus/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/rus/diagnosticMessages/diagnosticMessages.generated.json.lcl
index 7c2b517078c..bd78324f196 100644
--- a/src/loc/lcl/rus/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/rus/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -829,12 +829,12 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Добавьте {0} в существующее объявление импорта из {1}.]]></Val>
+            <Val><![CDATA[Добавьте "{0}" в существующее объявление импорта из "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Add {0} to existing import declaration from {1}]]></Val>
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -2240,6 +2240,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Преобразовать в импорт по умолчанию]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2897,6 +2906,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Ожидается аргументов типа: {0}–{1}. Укажите их с тегом "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2924,6 +2942,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Ожидается аргументов типа: {0}. Укажите их с тегом "@extends".]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2951,6 +2978,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Ожидался соответствующий закрывающий тег фрагмента JSX.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3679,16 +3715,28 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Импортируйте {0} из {1}.]]></Val>
+            <Val><![CDATA[Импортируйте "{0}" из "{1}".]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Import {0} from {1}]]></Val>
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Import_0_require_1_95015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Import '{0}' = require("{1}").]]></Val>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";Import_Asterisk_as_0_from_1_95016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Import * as '{0}' from "{1}".]]></Val>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Import_assignment_cannot_be_used_when_targeting_ECMAScript_modules_Consider_using_import_Asterisk_as_1202" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Import assignment cannot be used when targeting ECMAScript modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.]]></Val>
@@ -3920,6 +3968,12 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Install_0_95014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Install '{0}']]></Val>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Interface_0_cannot_simultaneously_extend_types_1_and_2_2320" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Interface '{0}' cannot simultaneously extend types '{1}' and '{2}'.]]></Val>
@@ -4193,6 +4247,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Фрагмент JSX не имеет соответствующего закрывающего тега.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Фрагмент JSX не поддерживается при использовании --jsxFactory]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6365,11 +6437,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Последующие объявления переменных должны иметь тот же тип. Переменная "{0}" должна иметь тип "{1}", однако имеет тип "{2}".]]></Val>
+            <Val><![CDATA[Последующие объявления переменных должны иметь тот же тип.  Переменная "{0}" должна иметь тип "{1}" в {2}, но имеет тип "{3}".]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/loc/lcl/trk/diagnosticMessages/diagnosticMessages.generated.json.lcl b/src/loc/lcl/trk/diagnosticMessages/diagnosticMessages.generated.json.lcl
index a30e3d898dc..0eafa4da0b2 100644
--- a/src/loc/lcl/trk/diagnosticMessages/diagnosticMessages.generated.json.lcl
+++ b/src/loc/lcl/trk/diagnosticMessages/diagnosticMessages.generated.json.lcl
@@ -823,12 +823,12 @@
       </Item>
       <Item ItemId=";Add_0_to_existing_import_declaration_from_1_90015" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
+          <Val><![CDATA[Add '{0}' to existing import declaration from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[{0} öğesini {1} konumundaki mevcut içeri aktarma bildirimine ekleyin.]]></Val>
+            <Val><![CDATA['{0}' öğesini "{1}" konumundaki mevcut içeri aktarma bildirimine ekleyin.]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Add {0} to existing import declaration from {1}]]></Val>
+            <Val><![CDATA[Add {0} to existing import declaration from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -2234,6 +2234,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Convert_to_default_import_95013" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Convert to default import]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[Varsayılan içeri aktarmaya dönüştür]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Corrupted_locale_file_0_6051" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Corrupted locale file {0}.]]></Val>
@@ -2891,6 +2900,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_1_type_arguments_provide_these_with_an_extends_tag_8027" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0}-{1} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[{0}-{1} türünde bağımsız değişkenler bekleniyordu; bunları bir '@extends' etiketiyle sağlayın.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_0_arguments_but_got_1_2554" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected {0} arguments, but got {1}.]]></Val>
@@ -2918,6 +2936,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_0_type_arguments_provide_these_with_an_extends_tag_8026" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected {0} type arguments; provide these with an '@extends' tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[{0} türünde bağımsız değişkenler bekleniyordu; bunları bir '@extends' etiketiyle sağlayın.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_at_least_0_arguments_but_got_1_2555" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected at least {0} arguments, but got {1}.]]></Val>
@@ -2945,6 +2972,15 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";Expected_corresponding_closing_tag_for_JSX_fragment_17015" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[Expected corresponding closing tag for JSX fragment.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX parçasına karşılık gelen kapanış etiketi bekleniyordu.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";Expected_type_of_0_field_in_package_json_to_be_string_got_1_6105" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.]]></Val>
@@ -3673,12 +3709,12 @@
       </Item>
       <Item ItemId=";Import_0_from_1_90013" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Import {0} from {1}.]]></Val>
+          <Val><![CDATA[Import '{0}' from "{1}".]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[{0} öğesini {1} kaynağından içeri aktarın.]]></Val>
+            <Val><![CDATA['{0}' öğesini "{1}" kaynağından içeri aktarın.]]></Val>
           </Tgt>
           <Prev Cat="Text">
-            <Val><![CDATA[Import {0} from {1}]]></Val>
+            <Val><![CDATA[Import {0} from {1}.]]></Val>
           </Prev>
         </Str>
         <Disp Icon="Str" />
@@ -4187,6 +4223,24 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
+      <Item ItemId=";JSX_fragment_has_no_corresponding_closing_tag_17014" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment has no corresponding closing tag.]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX parçasına karşılık gelen bir kapatma etiketi yok.]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
+      <Item ItemId=";JSX_fragment_is_not_supported_when_using_jsxFactory_17016" ItemType="0" PsrId="306" Leaf="true">
+        <Str Cat="Text">
+          <Val><![CDATA[JSX fragment is not supported when using --jsxFactory]]></Val>
+          <Tgt Cat="Text" Stat="Loc" Orig="New">
+            <Val><![CDATA[JSX parçası --jsxFactory kullanılırken desteklenmiyor]]></Val>
+          </Tgt>
+        </Str>
+        <Disp Icon="Str" />
+      </Item>
       <Item ItemId=";JSX_spread_child_must_be_an_array_type_2609" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
           <Val><![CDATA[JSX spread child must be an array type.]]></Val>
@@ -6359,11 +6413,11 @@
         </Str>
         <Disp Icon="Str" />
       </Item>
-      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_must_be_of_type_1_but_here_has_t_2403" ItemType="0" PsrId="306" Leaf="true">
+      <Item ItemId=";Subsequent_variable_declarations_must_have_the_same_type_Variable_0_has_type_1_at_2_but_here_has_typ_2403" ItemType="0" PsrId="306" Leaf="true">
         <Str Cat="Text">
-          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' must be of type '{1}', but here has type '{2}'.]]></Val>
+          <Val><![CDATA[Subsequent variable declarations must have the same type.  Variable '{0}' has type '{1}' at {2}, but here has type '{3}'.]]></Val>
           <Tgt Cat="Text" Stat="Loc" Orig="New">
-            <Val><![CDATA[Ardışık değişken bildirimleri aynı türe sahip olmalıdır. '{0}' değişkeni '{1}' türünde olmalıdır, ancak burada '{2}' türüne sahip.]]></Val>
+            <Val><![CDATA[Ardışık değişken bildirimleri aynı türe sahip olmalıdır.  '{0}' değişkeni {2} konumunda '{1}' türüne sahip olmasına rağmen burada '{3}' türüne sahip.]]></Val>
           </Tgt>
         </Str>
         <Disp Icon="Str" />
diff --git a/src/server/client.ts b/src/server/client.ts
index 2781d7cf20a..8286119e828 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -170,8 +170,8 @@ namespace ts.server {
             };
         }
 
-        getCompletionsAtPosition(fileName: string, position: number): CompletionInfo {
-            const args: protocol.CompletionsRequestArgs = this.createFileLocationRequestArgs(fileName, position);
+        getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined): CompletionInfo {
+            const args: protocol.CompletionsRequestArgs = { ...this.createFileLocationRequestArgs(fileName, position), ...options };
 
             const request = this.processRequest<protocol.CompletionsRequest>(CommandNames.Completions, args);
             const response = this.processResponse<protocol.CompletionsResponse>(request);
@@ -192,8 +192,8 @@ namespace ts.server {
             };
         }
 
-        getCompletionEntryDetails(fileName: string, position: number, entryName: string): CompletionEntryDetails {
-            const args: protocol.CompletionDetailsRequestArgs = { ...this.createFileLocationRequestArgs(fileName, position), entryNames: [entryName] };
+        getCompletionEntryDetails(fileName: string, position: number, entryName: string, _options: FormatCodeOptions | FormatCodeSettings | undefined, source: string | undefined): CompletionEntryDetails {
+            const args: protocol.CompletionDetailsRequestArgs = { ...this.createFileLocationRequestArgs(fileName, position), entryNames: [{ name: entryName, source }] };
 
             const request = this.processRequest<protocol.CompletionDetailsRequest>(CommandNames.CompletionDetails, args);
             const response = this.processResponse<protocol.CompletionDetailsResponse>(request);
@@ -270,6 +270,25 @@ namespace ts.server {
             }));
         }
 
+        getDefinitionAndBoundSpan(fileName: string, position: number): DefinitionInfoAndBoundSpan {
+            const args: protocol.FileLocationRequestArgs = this.createFileLocationRequestArgs(fileName, position);
+
+            const request = this.processRequest<protocol.DefinitionRequest>(CommandNames.DefinitionAndBoundSpan, args);
+            const response = this.processResponse<protocol.DefinitionInfoAndBoundSpanReponse>(request);
+
+            return {
+                definitions: response.body.definitions.map(entry => ({
+                    containerKind: ScriptElementKind.unknown,
+                    containerName: "",
+                    fileName: entry.file,
+                    textSpan: this.decodeSpan(entry),
+                    kind: ScriptElementKind.unknown,
+                    name: ""
+                })),
+                textSpan: this.decodeSpan(response.body.textSpan, request.arguments.file)
+            };
+        }
+
         getTypeDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[] {
             const args: protocol.FileLocationRequestArgs = this.createFileLocationRequestArgs(fileName, position);
 
@@ -324,7 +343,7 @@ namespace ts.server {
         }
 
         getSyntacticDiagnostics(file: string): Diagnostic[] {
-            const args: protocol.SyntacticDiagnosticsSyncRequestArgs = { file,  includeLinePosition: true };
+            const args: protocol.SyntacticDiagnosticsSyncRequestArgs = { file, includeLinePosition: true };
 
             const request = this.processRequest<protocol.SyntacticDiagnosticsSyncRequest>(CommandNames.SyntacticDiagnosticsSync, args);
             const response = this.processResponse<protocol.SyntacticDiagnosticsSyncResponse>(request);
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 0bd02f32d95..726621a540d 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -9,10 +9,12 @@
 namespace ts.server {
     export const maxProgramSizeForNonTsFiles = 20 * 1024 * 1024;
 
+    // tslint:disable variable-name
     export const ProjectsUpdatedInBackgroundEvent = "projectsUpdatedInBackground";
     export const ConfigFileDiagEvent = "configFileDiag";
     export const ProjectLanguageServiceStateEvent = "projectLanguageServiceState";
     export const ProjectInfoTelemetryEvent = "projectInfo";
+    // tslint:enable variable-name
 
     export interface ProjectsUpdatedInBackgroundEvent {
         eventName: typeof ProjectsUpdatedInBackgroundEvent;
@@ -78,9 +80,7 @@ namespace ts.server {
 
     export type ProjectServiceEvent = ProjectsUpdatedInBackgroundEvent | ConfigFileDiagEvent | ProjectLanguageServiceStateEvent | ProjectInfoTelemetryEvent;
 
-    export interface ProjectServiceEventHandler {
-        (event: ProjectServiceEvent): void;
-    }
+    export type ProjectServiceEventHandler = (event: ProjectServiceEvent) => void;
 
     export interface SafeList {
         [name: string]: { match: RegExp, exclude?: (string | number)[][], types?: string[] };
@@ -103,9 +103,9 @@ namespace ts.server {
 
     const compilerOptionConverters = prepareConvertersForEnumLikeCompilerOptions(optionDeclarations);
     const indentStyle = createMapFromTemplate({
-        "none": IndentStyle.None,
-        "block": IndentStyle.Block,
-        "smart": IndentStyle.Smart
+        none: IndentStyle.None,
+        block: IndentStyle.Block,
+        smart: IndentStyle.Smart
     });
 
     export interface TypesMapFile {
@@ -134,31 +134,31 @@ namespace ts.server {
     const defaultTypeSafeList: SafeList = {
         "jquery": {
             // jquery files can have names like "jquery-1.10.2.min.js" (or "jquery.intellisense.js")
-            "match": /jquery(-(\.?\d+)+)?(\.intellisense)?(\.min)?\.js$/i,
-            "types": ["jquery"]
+            match: /jquery(-(\.?\d+)+)?(\.intellisense)?(\.min)?\.js$/i,
+            types: ["jquery"]
         },
         "WinJS": {
             // e.g. c:/temp/UWApp1/lib/winjs-4.0.1/js/base.js
-            "match": /^(.*\/winjs-[.\d]+)\/js\/base\.js$/i,        // If the winjs/base.js file is found..
-            "exclude": [["^", 1, "/.*"]],                // ..then exclude all files under the winjs folder
-            "types": ["winjs"]                           // And fetch the @types package for WinJS
+            match: /^(.*\/winjs-[.\d]+)\/js\/base\.js$/i,        // If the winjs/base.js file is found..
+            exclude: [["^", 1, "/.*"]],                // ..then exclude all files under the winjs folder
+            types: ["winjs"]                           // And fetch the @types package for WinJS
         },
         "Kendo": {
             // e.g. /Kendo3/wwwroot/lib/kendo/kendo.all.min.js
-            "match": /^(.*\/kendo)\/kendo\.all\.min\.js$/i,
-            "exclude": [["^", 1, "/.*"]],
-            "types": ["kendo-ui"]
+            match: /^(.*\/kendo)\/kendo\.all\.min\.js$/i,
+            exclude: [["^", 1, "/.*"]],
+            types: ["kendo-ui"]
         },
         "Office Nuget": {
             // e.g. /scripts/Office/1/excel-15.debug.js
-            "match": /^(.*\/office\/1)\/excel-\d+\.debug\.js$/i, // Office NuGet package is installed under a "1/office" folder
-            "exclude": [["^", 1, "/.*"]],                     // Exclude that whole folder if the file indicated above is found in it
-            "types": ["office"]                               // @types package to fetch instead
+            match: /^(.*\/office\/1)\/excel-\d+\.debug\.js$/i, // Office NuGet package is installed under a "1/office" folder
+            exclude: [["^", 1, "/.*"]],                     // Exclude that whole folder if the file indicated above is found in it
+            types: ["office"]                               // @types package to fetch instead
         },
         "Minified files": {
             // e.g. /whatever/blah.min.js
-            "match": /^(.+\.min\.js)$/i,
-            "exclude": [["^", 1, "$"]]
+            match: /^(.+\.min\.js)$/i,
+            exclude: [["^", 1, "$"]]
         }
     };
 
@@ -203,8 +203,10 @@ namespace ts.server {
      * This helper function processes a list of projects and return the concatenated, sortd and deduplicated output of processing each project.
      */
     export function combineProjectOutput<T>(projects: ReadonlyArray<Project>, action: (project: Project) => ReadonlyArray<T>, comparer?: (a: T, b: T) => number, areEqual?: (a: T, b: T) => boolean) {
-        const result = flatMap(projects, action).sort(comparer);
-        return projects.length > 1 ? deduplicate(result, areEqual) : result;
+        const outputs = flatMap(projects, action);
+        return comparer
+            ? sortAndDeduplicate(outputs, comparer, areEqual)
+            : deduplicate(outputs, areEqual);
     }
 
     export interface HostConfiguration {
@@ -355,6 +357,10 @@ namespace ts.server {
          * Open files: with value being project root path, and key being Path of the file that is open
          */
         readonly openFiles = createMap<NormalizedPath>();
+        /**
+         * Map of open files that are opened without complete path but have projectRoot as current directory
+         */
+        private readonly openFilesWithNonRootedDiskPath = createMap<ScriptInfo>();
 
         private compilerOptionsForInferredProjects: CompilerOptions;
         private compilerOptionsForInferredProjectsPerProjectRoot = createMap<CompilerOptions>();
@@ -801,17 +807,14 @@ namespace ts.server {
 
                     // If the the added or created file or directory is not supported file name, ignore the file
                     // But when watched directory is added/removed, we need to reload the file list
-                    if (fileOrDirectoryPath !== directory && !isSupportedSourceFileName(fileOrDirectory, project.getCompilationSettings(), this.hostConfiguration.extraFileExtensions)) {
+                    if (fileOrDirectoryPath !== directory && hasExtension(fileOrDirectoryPath) && !isSupportedSourceFileName(fileOrDirectory, project.getCompilationSettings(), this.hostConfiguration.extraFileExtensions)) {
                         this.logger.info(`Project: ${configFilename} Detected file add/remove of non supported extension: ${fileOrDirectory}`);
                         return;
                     }
 
                     // Reload is pending, do the reload
-                    if (!project.pendingReload) {
-                        const configFileSpecs = project.configFileSpecs;
-                        const result = getFileNamesFromConfigSpecs(configFileSpecs, getDirectoryPath(configFilename), project.getCompilationSettings(), project.getCachedDirectoryStructureHost(), this.hostConfiguration.extraFileExtensions);
-                        project.updateErrorOnNoInputFiles(result.fileNames.length !== 0);
-                        this.updateNonInferredProjectFiles(project, result.fileNames, fileNamePropertyReader);
+                    if (project.pendingReload !== ConfigFileProgramReloadLevel.Full) {
+                        project.pendingReload = ConfigFileProgramReloadLevel.Partial;
                         this.delayUpdateProjectGraphAndInferredProjectsRefresh(project);
                     }
                 },
@@ -844,7 +847,7 @@ namespace ts.server {
             }
             else {
                 this.logConfigFileWatchUpdate(project.getConfigFilePath(), project.canonicalConfigFilePath, configFileExistenceInfo, ConfigFileWatcherStatus.ReloadingInferredRootFiles);
-                project.pendingReload = true;
+                project.pendingReload = ConfigFileProgramReloadLevel.Full;
                 this.delayUpdateProjectGraph(project);
                 // As we scheduled the update on configured project graph,
                 // we would need to schedule the project reload for only the root of inferred projects
@@ -938,12 +941,16 @@ namespace ts.server {
             // Closing file should trigger re-reading the file content from disk. This is
             // because the user may chose to discard the buffer content before saving
             // to the disk, and the server's version of the file can be out of sync.
-            info.close();
+            const fileExists = this.host.fileExists(info.fileName);
+            info.close(fileExists);
             this.stopWatchingConfigFilesForClosedScriptInfo(info);
 
             this.openFiles.delete(info.path);
+            const canonicalFileName = this.toCanonicalFileName(info.fileName);
+            if (this.openFilesWithNonRootedDiskPath.get(canonicalFileName) === info) {
+                this.openFilesWithNonRootedDiskPath.delete(canonicalFileName);
+            }
 
-            const fileExists = this.host.fileExists(info.fileName);
 
             // collect all projects that should be removed
             let projectsToRemove: Project[];
@@ -1069,7 +1076,7 @@ namespace ts.server {
          * Returns true if the configFileExistenceInfo is needed/impacted by open files that are root of inferred project
          */
         private configFileExistenceImpactsRootOfInferredProject(configFileExistenceInfo: ConfigFileExistenceInfo) {
-            return forEachEntry(configFileExistenceInfo.openFilesImpactedByConfigFile, (isRootOfInferredProject, __key) => isRootOfInferredProject);
+            return forEachEntry(configFileExistenceInfo.openFilesImpactedByConfigFile, (isRootOfInferredProject) => isRootOfInferredProject);
         }
 
         private setConfigFileExistenceInfoByClosedConfiguredProject(closedProject: ConfiguredProject) {
@@ -1379,24 +1386,42 @@ namespace ts.server {
             this.projectToSizeMap.forEach(val => (availableSpace -= (val || 0)));
 
             let totalNonTsFileSize = 0;
+
             for (const f of fileNames) {
                 const fileName = propertyReader.getFileName(f);
                 if (hasTypeScriptFileExtension(fileName)) {
                     continue;
                 }
+
                 totalNonTsFileSize += this.host.getFileSize(fileName);
+
                 if (totalNonTsFileSize > maxProgramSizeForNonTsFiles) {
+                    this.logger.info(getExceedLimitMessage({ propertyReader, hasTypeScriptFileExtension, host: this.host }, totalNonTsFileSize));
                     // Keep the size as zero since it's disabled
                     return true;
                 }
             }
 
             if (totalNonTsFileSize > availableSpace) {
+                this.logger.info(getExceedLimitMessage({ propertyReader, hasTypeScriptFileExtension, host: this.host }, totalNonTsFileSize));
                 return true;
             }
 
             this.projectToSizeMap.set(name, totalNonTsFileSize);
             return false;
+
+            function getExceedLimitMessage(context: { propertyReader: FilePropertyReader<any>, hasTypeScriptFileExtension: (filename: string) => boolean, host: ServerHost }, totalNonTsFileSize: number) {
+                const files = getTop5LargestFiles(context);
+
+                return `Non TS file size exceeded limit (${totalNonTsFileSize}). Largest files: ${files.map(file => `${file.name}:${file.size}`).join(", ")}`;
+            }
+            function getTop5LargestFiles({ propertyReader, hasTypeScriptFileExtension, host }: { propertyReader: FilePropertyReader<any>, hasTypeScriptFileExtension: (filename: string) => boolean, host: ServerHost }) {
+                return fileNames.map(f => propertyReader.getFileName(f))
+                    .filter(name => hasTypeScriptFileExtension(name))
+                    .map(name => ({ name, size: host.getFileSize(name) }))
+                    .sort((a, b) => b.size - a.size)
+                    .slice(0, 5);
+            }
         }
 
         private createExternalProject(projectFileName: string, files: protocol.ExternalFile[], options: protocol.ExternalProjectCompilerOptions, typeAcquisition: TypeAcquisition, excludedFiles: NormalizedPath[]) {
@@ -1526,7 +1551,7 @@ namespace ts.server {
                 else {
                     const scriptKind = propertyReader.getScriptKind(f, this.hostConfiguration.extraFileExtensions);
                     const hasMixedContent = propertyReader.hasMixedContent(f, this.hostConfiguration.extraFileExtensions);
-                    scriptInfo = this.getOrCreateScriptInfoNotOpenedByClientForNormalizedPath(normalizedPath, scriptKind, hasMixedContent, project.directoryStructureHost);
+                    scriptInfo = this.getOrCreateScriptInfoNotOpenedByClientForNormalizedPath(normalizedPath, project.currentDirectory, scriptKind, hasMixedContent, project.directoryStructureHost);
                     path = scriptInfo.path;
                     // If this script info is not already a root add it
                     if (!project.isRoot(scriptInfo)) {
@@ -1571,6 +1596,19 @@ namespace ts.server {
             this.addFilesToNonInferredProjectAndUpdateGraph(project, newUncheckedFiles, propertyReader, newTypeAcquisition);
         }
 
+        /**
+         * Reload the file names from config file specs and update the project graph
+         */
+        /*@internal*/
+        reloadFileNamesOfConfiguredProject(project: ConfiguredProject): boolean {
+            const configFileSpecs = project.configFileSpecs;
+            const configFileName = project.getConfigFilePath();
+            const fileNamesResult = getFileNamesFromConfigSpecs(configFileSpecs, getDirectoryPath(configFileName), project.getCompilationSettings(), project.getCachedDirectoryStructureHost(), this.hostConfiguration.extraFileExtensions);
+            project.updateErrorOnNoInputFiles(fileNamesResult.fileNames.length !== 0);
+            this.updateNonInferredProjectFiles(project, fileNamesResult.fileNames, fileNamePropertyReader);
+            return project.updateGraph();
+        }
+
         /**
          * Read the config file of the project again and update the project
          */
@@ -1680,9 +1718,9 @@ namespace ts.server {
         }
 
         /*@internal*/
-        getOrCreateScriptInfoNotOpenedByClient(uncheckedFileName: string, hostToQueryFileExistsOn: DirectoryStructureHost) {
+        getOrCreateScriptInfoNotOpenedByClient(uncheckedFileName: string, currentDirectory: string, hostToQueryFileExistsOn: DirectoryStructureHost) {
             return this.getOrCreateScriptInfoNotOpenedByClientForNormalizedPath(
-                toNormalizedPath(uncheckedFileName), /*scriptKind*/ undefined,
+                toNormalizedPath(uncheckedFileName), currentDirectory, /*scriptKind*/ undefined,
                 /*hasMixedContent*/ undefined, hostToQueryFileExistsOn
             );
         }
@@ -1713,20 +1751,26 @@ namespace ts.server {
         }
 
         /*@internal*/
-        getOrCreateScriptInfoNotOpenedByClientForNormalizedPath(fileName: NormalizedPath, scriptKind?: ScriptKind, hasMixedContent?: boolean, hostToQueryFileExistsOn?: DirectoryStructureHost) {
-            return this.getOrCreateScriptInfoForNormalizedPath(fileName, /*openedByClient*/ false, /*fileContent*/ undefined, scriptKind, hasMixedContent, hostToQueryFileExistsOn);
+        getOrCreateScriptInfoNotOpenedByClientForNormalizedPath(fileName: NormalizedPath, currentDirectory: string, scriptKind: ScriptKind | undefined, hasMixedContent: boolean | undefined, hostToQueryFileExistsOn: DirectoryStructureHost | undefined) {
+            return this.getOrCreateScriptInfoWorker(fileName, currentDirectory, /*openedByClient*/ false, /*fileContent*/ undefined, scriptKind, hasMixedContent, hostToQueryFileExistsOn);
         }
 
         /*@internal*/
-        getOrCreateScriptInfoOpenedByClientForNormalizedPath(fileName: NormalizedPath, fileContent?: string, scriptKind?: ScriptKind, hasMixedContent?: boolean, hostToQueryFileExistsOn?: DirectoryStructureHost) {
-            return this.getOrCreateScriptInfoForNormalizedPath(fileName, /*openedByClient*/ true, fileContent, scriptKind, hasMixedContent, hostToQueryFileExistsOn);
+        getOrCreateScriptInfoOpenedByClientForNormalizedPath(fileName: NormalizedPath, currentDirectory: string, fileContent: string | undefined, scriptKind: ScriptKind | undefined, hasMixedContent: boolean | undefined) {
+            return this.getOrCreateScriptInfoWorker(fileName, currentDirectory, /*openedByClient*/ true, fileContent, scriptKind, hasMixedContent);
         }
 
         getOrCreateScriptInfoForNormalizedPath(fileName: NormalizedPath, openedByClient: boolean, fileContent?: string, scriptKind?: ScriptKind, hasMixedContent?: boolean, hostToQueryFileExistsOn?: DirectoryStructureHost) {
+            return this.getOrCreateScriptInfoWorker(fileName, this.currentDirectory, openedByClient, fileContent, scriptKind, hasMixedContent, hostToQueryFileExistsOn);
+        }
+
+        private getOrCreateScriptInfoWorker(fileName: NormalizedPath, currentDirectory: string, openedByClient: boolean, fileContent?: string, scriptKind?: ScriptKind, hasMixedContent?: boolean, hostToQueryFileExistsOn?: DirectoryStructureHost) {
             Debug.assert(fileContent === undefined || openedByClient, "ScriptInfo needs to be opened by client to be able to set its user defined content");
-            const path = normalizedPathToPath(fileName, this.currentDirectory, this.toCanonicalFileName);
+            const path = normalizedPathToPath(fileName, currentDirectory, this.toCanonicalFileName);
             let info = this.getScriptInfoForPath(path);
             if (!info) {
+                Debug.assert(isRootedDiskPath(fileName) || openedByClient, "Script info with relative file name can only be open script info");
+                Debug.assert(!isRootedDiskPath(fileName) || this.currentDirectory === currentDirectory || !this.openFilesWithNonRootedDiskPath.has(this.toCanonicalFileName(fileName)), "Open script files with non rooted disk path opened with current directory context cannot have same canonical names");
                 const isDynamic = isDynamicFileName(fileName);
                 // If the file is not opened by client and the file doesnot exist on the disk, return
                 if (!openedByClient && !isDynamic && !(hostToQueryFileExistsOn || this.host).fileExists(fileName)) {
@@ -1737,6 +1781,10 @@ namespace ts.server {
                 if (!openedByClient) {
                     this.watchClosedScriptInfo(info);
                 }
+                else if (!isRootedDiskPath(fileName) && currentDirectory !== this.currentDirectory) {
+                    // File that is opened by user but isn't rooted disk path
+                    this.openFilesWithNonRootedDiskPath.set(this.toCanonicalFileName(fileName), info);
+                }
             }
             if (openedByClient && !info.isScriptOpen()) {
                 // Opening closed script info
@@ -1753,8 +1801,12 @@ namespace ts.server {
             return info;
         }
 
+        /**
+         * This gets the script info for the normalized path. If the path is not rooted disk path then the open script info with project root context is preferred
+         */
         getScriptInfoForNormalizedPath(fileName: NormalizedPath) {
-            return this.getScriptInfoForPath(normalizedPathToPath(fileName, this.currentDirectory, this.toCanonicalFileName));
+            return !isRootedDiskPath(fileName) && this.openFilesWithNonRootedDiskPath.get(this.toCanonicalFileName(fileName)) ||
+                this.getScriptInfoForPath(normalizedPathToPath(fileName, this.currentDirectory, this.toCanonicalFileName));
         }
 
         getScriptInfoForPath(fileName: Path) {
@@ -1851,7 +1903,7 @@ namespace ts.server {
                     }
                     else if (!updatedProjects.has(configFileName)) {
                         if (delayReload) {
-                            project.pendingReload = true;
+                            project.pendingReload = ConfigFileProgramReloadLevel.Full;
                             this.delayUpdateProjectGraph(project);
                         }
                         else {
@@ -1939,7 +1991,7 @@ namespace ts.server {
             let sendConfigFileDiagEvent = false;
             let configFileErrors: ReadonlyArray<Diagnostic>;
 
-            const info = this.getOrCreateScriptInfoOpenedByClientForNormalizedPath(fileName, fileContent, scriptKind, hasMixedContent);
+            const info = this.getOrCreateScriptInfoOpenedByClientForNormalizedPath(fileName, projectRootPath ? this.getNormalizedAbsolutePath(projectRootPath) : this.currentDirectory, fileContent, scriptKind, hasMixedContent);
             let project: ConfiguredProject | ExternalProject = this.findContainingExternalProject(fileName);
             if (!project) {
                 configFileName = this.getConfigFileNameForFile(info, projectRootPath);
diff --git a/src/server/project.ts b/src/server/project.ts
index 0e1e7ac2cab..d2526ab2abb 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -98,9 +98,7 @@ namespace ts.server {
         getExternalFiles?(proj: Project): string[];
     }
 
-    export interface PluginModuleFactory {
-        (mod: { typescript: typeof ts }): PluginModule;
-    }
+    export type PluginModuleFactory = (mod: { typescript: typeof ts }) => PluginModule;
 
     /**
      * The project root can be script info - if root is present,
@@ -287,7 +285,7 @@ namespace ts.server {
         }
 
         private getOrCreateScriptInfoAndAttachToProject(fileName: string) {
-            const scriptInfo = this.projectService.getOrCreateScriptInfoNotOpenedByClient(fileName, this.directoryStructureHost);
+            const scriptInfo = this.projectService.getOrCreateScriptInfoNotOpenedByClient(fileName, this.currentDirectory, this.directoryStructureHost);
             if (scriptInfo) {
                 const existingValue = this.rootFilesMap.get(scriptInfo.path);
                 if (existingValue !== scriptInfo && existingValue !== undefined) {
@@ -367,7 +365,7 @@ namespace ts.server {
 
         /*@internal*/
         toPath(fileName: string) {
-            return this.projectService.toPath(fileName);
+            return toPath(fileName, this.currentDirectory, this.projectService.toCanonicalFileName);
         }
 
         /*@internal*/
@@ -660,7 +658,7 @@ namespace ts.server {
         }
 
         containsFile(filename: NormalizedPath, requireOpen?: boolean) {
-            const info = this.projectService.getScriptInfoForNormalizedPath(filename);
+            const info = this.projectService.getScriptInfoForPath(this.toPath(filename));
             if (info && (info.isScriptOpen() || !requireOpen)) {
                 return this.containsScriptInfo(info);
             }
@@ -857,10 +855,11 @@ namespace ts.server {
                 // by the LSHost for files in the program when the program is retrieved above but
                 // the program doesn't contain external files so this must be done explicitly.
                 inserted => {
-                    const scriptInfo = this.projectService.getOrCreateScriptInfoNotOpenedByClient(inserted, this.directoryStructureHost);
+                    const scriptInfo = this.projectService.getOrCreateScriptInfoNotOpenedByClient(inserted, this.currentDirectory, this.directoryStructureHost);
                     scriptInfo.attachToProject(this);
                 },
-                removed => this.detachScriptInfoFromProject(removed)
+                removed => this.detachScriptInfoFromProject(removed),
+                compareStringsCaseSensitive
             );
             const elapsed = timestamp() - start;
             this.writeLog(`Finishing updateGraphWorker: Project: ${this.getProjectName()} structureChanged: ${hasChanges} Elapsed: ${elapsed}ms`);
@@ -903,7 +902,7 @@ namespace ts.server {
         }
 
         getScriptInfoForNormalizedPath(fileName: NormalizedPath) {
-            const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(fileName);
+            const scriptInfo = this.projectService.getScriptInfoForPath(this.toPath(fileName));
             if (scriptInfo && !scriptInfo.isAttached(this)) {
                 return Errors.ThrowProjectDoesNotContainDocument(fileName, this);
             }
@@ -1123,7 +1122,7 @@ namespace ts.server {
         readonly canonicalConfigFilePath: NormalizedPath;
 
         /* @internal */
-        pendingReload: boolean;
+        pendingReload: ConfigFileProgramReloadLevel;
 
         /*@internal*/
         configFileSpecs: ConfigFileSpecs;
@@ -1163,12 +1162,17 @@ namespace ts.server {
          * @returns: true if set of files in the project stays the same and false - otherwise.
          */
         updateGraph(): boolean {
-            if (this.pendingReload) {
-                this.pendingReload = false;
-                this.projectService.reloadConfiguredProject(this);
-                return true;
+            const reloadLevel = this.pendingReload;
+            this.pendingReload = ConfigFileProgramReloadLevel.None;
+            switch (reloadLevel) {
+                case ConfigFileProgramReloadLevel.Partial:
+                    return this.projectService.reloadFileNamesOfConfiguredProject(this);
+                case ConfigFileProgramReloadLevel.Full:
+                    this.projectService.reloadConfiguredProject(this);
+                    return true;
+                default:
+                    return super.updateGraph();
             }
-            return super.updateGraph();
         }
 
         /*@internal*/
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index 6092f235942..f44efa0db21 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -15,12 +15,17 @@ namespace ts.server.protocol {
         /* @internal */
         CompletionsFull = "completions-full",
         CompletionDetails = "completionEntryDetails",
+        /* @internal */
+        CompletionDetailsFull = "completionEntryDetails-full",
         CompileOnSaveAffectedFileList = "compileOnSaveAffectedFileList",
         CompileOnSaveEmitFile = "compileOnSaveEmitFile",
         Configure = "configure",
         Definition = "definition",
         /* @internal */
         DefinitionFull = "definition-full",
+        DefinitionAndBoundSpan = "definitionAndBoundSpan",
+        /* @internal */
+        DefinitionAndBoundSpanFull = "definitionAndBoundSpan-full",
         Implementation = "implementation",
         /* @internal */
         ImplementationFull = "implementation-full",
@@ -708,6 +713,11 @@ namespace ts.server.protocol {
         file: string;
     }
 
+    export interface DefinitionInfoAndBoundSpan {
+        definitions: ReadonlyArray<FileSpan>;
+        textSpan: TextSpan;
+    }
+
     /**
      * Definition response message.  Gives text range for definition.
      */
@@ -715,6 +725,10 @@ namespace ts.server.protocol {
         body?: FileSpan[];
     }
 
+    export interface DefinitionInfoAndBoundSpanReponse extends Response {
+        body?: DefinitionInfoAndBoundSpan;
+    }
+
     /**
      * Definition response message.  Gives text range for definition.
      */
@@ -1605,6 +1619,11 @@ namespace ts.server.protocol {
          * Optional prefix to apply to possible completions.
          */
         prefix?: string;
+        /**
+         * If enabled, TypeScript will search through all external modules' exports and add them to the completions list.
+         * This affects lone identifier completions but not completions on the right hand side of `obj.`.
+         */
+        includeExternalModuleExports: boolean;
     }
 
     /**
diff --git a/src/server/scriptInfo.ts b/src/server/scriptInfo.ts
index 9f029c00f0a..f800a1117d0 100644
--- a/src/server/scriptInfo.ts
+++ b/src/server/scriptInfo.ts
@@ -248,9 +248,9 @@ namespace ts.server {
             }
         }
 
-        public close() {
+        public close(fileExists = true) {
             this.textStorage.isOpen = false;
-            if (this.isDynamicOrHasMixedContent()) {
+            if (this.isDynamicOrHasMixedContent() || !fileExists) {
                 if (this.textStorage.reload("")) {
                     this.markContainingProjectsAsDirty();
                 }
diff --git a/src/server/scriptVersionCache.ts b/src/server/scriptVersionCache.ts
index 7c25e4cc3cb..fe71040b4f6 100644
--- a/src/server/scriptVersionCache.ts
+++ b/src/server/scriptVersionCache.ts
@@ -10,7 +10,7 @@ namespace ts.server {
         charCount(): number;
         lineCount(): number;
         isLeaf(): this is LineLeaf;
-        walk(rangeStart: number, rangeLength: number, walkFns: ILineIndexWalker): void;
+        walk(rangeStart: number, rangeLength: number, walkFns: LineIndexWalker): void;
     }
 
     export interface AbsolutePositionAndLineText {
@@ -27,7 +27,7 @@ namespace ts.server {
         PostEnd
     }
 
-    interface ILineIndexWalker {
+    interface LineIndexWalker {
         goSubtree: boolean;
         done: boolean;
         leaf(relativeStart: number, relativeLength: number, lineCollection: LineLeaf): void;
@@ -37,7 +37,7 @@ namespace ts.server {
             parent: LineNode, nodeType: CharRangeSection): void;
     }
 
-    class EditWalker implements ILineIndexWalker {
+    class EditWalker implements LineIndexWalker {
         goSubtree = true;
         get done() { return false; }
 
@@ -429,7 +429,7 @@ namespace ts.server {
             }
         }
 
-        walk(rangeStart: number, rangeLength: number, walkFns: ILineIndexWalker) {
+        walk(rangeStart: number, rangeLength: number, walkFns: LineIndexWalker) {
             this.root.walk(rangeStart, rangeLength, walkFns);
         }
 
@@ -458,7 +458,7 @@ namespace ts.server {
             const walkFns = {
                 goSubtree: true,
                 done: false,
-                leaf(this: ILineIndexWalker, relativeStart: number, relativeLength: number, ll: LineLeaf) {
+                leaf(this: LineIndexWalker, relativeStart: number, relativeLength: number, ll: LineLeaf) {
                     if (!f(ll, relativeStart, relativeLength)) {
                         this.done = true;
                     }
@@ -580,7 +580,7 @@ namespace ts.server {
             }
         }
 
-        private execWalk(rangeStart: number, rangeLength: number, walkFns: ILineIndexWalker, childIndex: number, nodeType: CharRangeSection) {
+        private execWalk(rangeStart: number, rangeLength: number, walkFns: LineIndexWalker, childIndex: number, nodeType: CharRangeSection) {
             if (walkFns.pre) {
                 walkFns.pre(rangeStart, rangeLength, this.children[childIndex], this, nodeType);
             }
@@ -596,14 +596,14 @@ namespace ts.server {
             return walkFns.done;
         }
 
-        private skipChild(relativeStart: number, relativeLength: number, childIndex: number, walkFns: ILineIndexWalker, nodeType: CharRangeSection) {
+        private skipChild(relativeStart: number, relativeLength: number, childIndex: number, walkFns: LineIndexWalker, nodeType: CharRangeSection) {
             if (walkFns.pre && (!walkFns.done)) {
                 walkFns.pre(relativeStart, relativeLength, this.children[childIndex], this, nodeType);
                 walkFns.goSubtree = true;
             }
         }
 
-        walk(rangeStart: number, rangeLength: number, walkFns: ILineIndexWalker) {
+        walk(rangeStart: number, rangeLength: number, walkFns: LineIndexWalker) {
             // assume (rangeStart < this.totalChars) && (rangeLength <= this.totalChars)
             let childIndex = 0;
             let childCharCount = this.children[childIndex].charCount();
@@ -814,7 +814,7 @@ namespace ts.server {
             return true;
         }
 
-        walk(rangeStart: number, rangeLength: number, walkFns: ILineIndexWalker) {
+        walk(rangeStart: number, rangeLength: number, walkFns: LineIndexWalker) {
             walkFns.leaf(rangeStart, rangeLength, this);
         }
 
diff --git a/src/server/server.ts b/src/server/server.ts
index 01dba98a503..f4faa0d3c77 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -3,7 +3,7 @@
 /// <reference path="session.ts" />
 
 namespace ts.server {
-    interface IOSessionOptions {
+    interface IoSessionOptions {
         host: ServerHost;
         cancellationToken: ServerCancellationToken;
         canUseEvents: boolean;
@@ -200,7 +200,7 @@ namespace ts.server {
             return this.loggingEnabled() && this.level >= level;
         }
 
-        msg(s: string, type: Msg.Types = Msg.Err) {
+        msg(s: string, type: Msg = Msg.Err) {
             if (!this.canWrite) return;
 
             s = `[${nowString()}] ${s}\n`;
@@ -529,7 +529,7 @@ namespace ts.server {
     }
 
     class IOSession extends Session {
-        constructor(options: IOSessionOptions) {
+        constructor(options: IoSessionOptions) {
             const { host, installerEventPort, globalTypingsCacheLocation, typingSafeListLocation, typesMapLocation, npmLocation, canUseEvents } = options;
             const typingsInstaller = disableAutomaticTypingAcquisition
                 ? undefined
@@ -816,7 +816,7 @@ namespace ts.server {
     if (useWatchGuard) {
         const currentDrive = extractWatchDirectoryCacheKey(sys.resolvePath(sys.getCurrentDirectory()), /*currentDriveKey*/ undefined);
         const statusCache = createMap<boolean>();
-        sys.watchDirectory = function (path: string, callback: DirectoryWatcherCallback, recursive?: boolean): FileWatcher {
+        sys.watchDirectory = (path, callback, recursive) => {
             const cacheKey = extractWatchDirectoryCacheKey(path, currentDrive);
             let status = cacheKey && statusCache.get(cacheKey);
             if (status === undefined) {
@@ -828,7 +828,7 @@ namespace ts.server {
                     if (logger.hasLevel(LogLevel.verbose)) {
                         logger.info(`Starting ${process.execPath} with args:${stringifyIndented(args)}`);
                     }
-                    childProcess.execFileSync(process.execPath, args, { stdio: "ignore", env: { "ELECTRON_RUN_AS_NODE": "1" } });
+                    childProcess.execFileSync(process.execPath, args, { stdio: "ignore", env: { ELECTRON_RUN_AS_NODE: "1" } });
                     status = true;
                     if (logger.hasLevel(LogLevel.verbose)) {
                         logger.info(`WatchGuard for path ${path} returned: OK`);
@@ -933,7 +933,7 @@ namespace ts.server {
     const disableAutomaticTypingAcquisition = hasArgument("--disableAutomaticTypingAcquisition");
     const telemetryEnabled = hasArgument(Arguments.EnableTelemetry);
 
-    const options: IOSessionOptions = {
+    const options: IoSessionOptions = {
         host: sys,
         cancellationToken,
         installerEventPort: eventPort,
@@ -953,7 +953,7 @@ namespace ts.server {
     };
 
     const ioSession = new IOSession(options);
-    process.on("uncaughtException", function (err: Error) {
+    process.on("uncaughtException", err => {
         ioSession.logError(err, "unknown");
     });
     // See https://github.com/Microsoft/TypeScript/issues/11348
diff --git a/src/server/session.ts b/src/server/session.ts
index 7ada8d2ff9c..6c97c3c8bd4 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -124,7 +124,7 @@ namespace ts.server {
     // we want to ensure the value is maintained in the out since the file is
     // built using --preseveConstEnum.
     export type CommandNames = protocol.CommandTypes;
-    export const CommandNames = (<any>protocol).CommandTypes;
+    export const CommandNames = (<any>protocol).CommandTypes; // tslint:disable-line variable-name
 
     export function formatMessage<T extends protocol.Message>(msg: T, logger: server.Logger, byteLength: (s: string, encoding: string) => number, newLine: string): string {
         const verboseLogging = logger.hasLevel(LogLevel.verbose);
@@ -167,7 +167,7 @@ namespace ts.server {
         private timerHandle: any;
         private immediateId: number | undefined;
 
-        constructor(private readonly operationHost: MultistepOperationHost) {}
+        constructor(private readonly operationHost: MultistepOperationHost) { }
 
         public startNew(action: (next: NextStep) => void) {
             this.complete();
@@ -587,7 +587,7 @@ namespace ts.server {
 
         private getDiagnosticsWorker(
             args: protocol.FileRequestArgs, isSemantic: boolean, selector: (project: Project, file: string) => ReadonlyArray<Diagnostic>, includeLinePosition: boolean
-            ): ReadonlyArray<protocol.DiagnosticWithLinePosition> | ReadonlyArray<protocol.Diagnostic> {
+        ): ReadonlyArray<protocol.DiagnosticWithLinePosition> | ReadonlyArray<protocol.Diagnostic> {
             const { project, file } = this.getFileAndProject(args);
             if (isSemantic && isDeclarationFileInJSOnlyNonConfiguredProject(project, file)) {
                 return emptyArray;
@@ -609,20 +609,51 @@ namespace ts.server {
             }
 
             if (simplifiedResult) {
-                return definitions.map(def => {
-                    const defScriptInfo = project.getScriptInfo(def.fileName);
-                    return {
-                        file: def.fileName,
-                        start: defScriptInfo.positionToLineOffset(def.textSpan.start),
-                        end: defScriptInfo.positionToLineOffset(textSpanEnd(def.textSpan))
-                    };
-                });
+                return this.mapDefinitionInfo(definitions, project);
             }
             else {
                 return definitions;
             }
         }
 
+        private getDefinitionAndBoundSpan(args: protocol.FileLocationRequestArgs, simplifiedResult: boolean): protocol.DefinitionInfoAndBoundSpan | DefinitionInfoAndBoundSpan {
+            const { file, project } = this.getFileAndProject(args);
+            const position = this.getPositionInFile(args, file);
+            const scriptInfo = project.getScriptInfo(file);
+
+            const definitionAndBoundSpan = project.getLanguageService().getDefinitionAndBoundSpan(file, position);
+
+            if (!definitionAndBoundSpan || !definitionAndBoundSpan.definitions) {
+                return {
+                    definitions: emptyArray,
+                    textSpan: undefined
+                };
+            }
+
+            if (simplifiedResult) {
+                return {
+                    definitions: this.mapDefinitionInfo(definitionAndBoundSpan.definitions, project),
+                    textSpan: this.toLocationTextSpan(definitionAndBoundSpan.textSpan, scriptInfo)
+                };
+            }
+
+            return definitionAndBoundSpan;
+        }
+
+        private mapDefinitionInfo(definitions: ReadonlyArray<DefinitionInfo>, project: Project): ReadonlyArray<protocol.FileSpan> {
+            return definitions.map(def => this.toFileSpan(def.fileName, def.textSpan, project));
+        }
+
+        private toFileSpan(fileName: string, textSpan: TextSpan, project: Project): protocol.FileSpan {
+            const scriptInfo = project.getScriptInfo(fileName);
+
+            return {
+                file: fileName,
+                start: scriptInfo.positionToLineOffset(textSpan.start),
+                end: scriptInfo.positionToLineOffset(textSpanEnd(textSpan))
+            };
+        }
+
         private getTypeDefinition(args: protocol.FileLocationRequestArgs): ReadonlyArray<protocol.FileSpan> {
             const { file, project } = this.getFileAndProject(args);
             const position = this.getPositionInFile(args, file);
@@ -632,14 +663,7 @@ namespace ts.server {
                 return emptyArray;
             }
 
-            return definitions.map(def => {
-                const defScriptInfo = project.getScriptInfo(def.fileName);
-                return {
-                    file: def.fileName,
-                    start: defScriptInfo.positionToLineOffset(def.textSpan.start),
-                    end: defScriptInfo.positionToLineOffset(textSpanEnd(def.textSpan))
-                };
-            });
+            return this.mapDefinitionInfo(definitions, project);
         }
 
         private getImplementation(args: protocol.FileLocationRequestArgs, simplifiedResult: boolean): ReadonlyArray<protocol.FileSpan> | ReadonlyArray<ImplementationLocation> {
@@ -650,14 +674,7 @@ namespace ts.server {
                 return emptyArray;
             }
             if (simplifiedResult) {
-                return implementations.map(({ fileName, textSpan }) => {
-                    const scriptInfo = project.getScriptInfo(fileName);
-                    return {
-                        file: fileName,
-                        start: scriptInfo.positionToLineOffset(textSpan.start),
-                        end: scriptInfo.positionToLineOffset(textSpanEnd(textSpan))
-                    };
-                });
+                return implementations.map(({ fileName, textSpan }) => this.toFileSpan(fileName, textSpan, project));
             }
             else {
                 return implementations;
@@ -666,6 +683,7 @@ namespace ts.server {
 
         private getOccurrences(args: protocol.FileLocationRequestArgs): ReadonlyArray<protocol.OccurrencesResponseItem> {
             const { file, project } = this.getFileAndProject(args);
+
             const position = this.getPositionInFile(args, file);
 
             const occurrences = project.getLanguageService().getOccurrencesAtPosition(file, position);
@@ -677,11 +695,9 @@ namespace ts.server {
             return occurrences.map(occurrence => {
                 const { fileName, isWriteAccess, textSpan, isInString } = occurrence;
                 const scriptInfo = project.getScriptInfo(fileName);
-                const start = scriptInfo.positionToLineOffset(textSpan.start);
-                const end = scriptInfo.positionToLineOffset(textSpanEnd(textSpan));
                 const result: protocol.OccurrencesResponseItem = {
-                    start,
-                    end,
+                    start: scriptInfo.positionToLineOffset(textSpan.start),
+                    end: scriptInfo.positionToLineOffset(textSpanEnd(textSpan)),
                     file: fileName,
                     isWriteAccess,
                 };
@@ -958,7 +974,7 @@ namespace ts.server {
                     projects,
                     project => project.getLanguageService().findReferences(file, position),
                     /*comparer*/ undefined,
-                    /*areEqual (TODO: fixme)*/ undefined
+                    equateValues
                 );
             }
 
@@ -1184,39 +1200,35 @@ namespace ts.server {
             const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(file);
             const position = this.getPosition(args, scriptInfo);
 
-            const completions = project.getLanguageService().getCompletionsAtPosition(file, position);
+            const completions = project.getLanguageService().getCompletionsAtPosition(file, position, args);
             if (simplifiedResult) {
                 return mapDefined<CompletionEntry, protocol.CompletionEntry>(completions && completions.entries, entry => {
-                    if (completions.isMemberCompletion || (entry.name.toLowerCase().indexOf(prefix.toLowerCase()) === 0)) {
+                    if (completions.isMemberCompletion || startsWith(entry.name.toLowerCase(), prefix.toLowerCase())) {
                         const { name, kind, kindModifiers, sortText, replacementSpan, hasAction, source } = entry;
-                        const convertedSpan = replacementSpan ? this.decorateSpan(replacementSpan, scriptInfo) : undefined;
+                        const convertedSpan = replacementSpan ? this.toLocationTextSpan(replacementSpan, scriptInfo) : undefined;
                         // Use `hasAction || undefined` to avoid serializing `false`.
                         return { name, kind, kindModifiers, sortText, replacementSpan: convertedSpan, hasAction: hasAction || undefined, source };
                     }
-                }).sort((a, b) => compareStrings(a.name, b.name));
+                }).sort((a, b) => compareStringsCaseSensitiveUI(a.name, b.name));
             }
             else {
                 return completions;
             }
         }
 
-        private getCompletionEntryDetails(args: protocol.CompletionDetailsRequestArgs): ReadonlyArray<protocol.CompletionEntryDetails> {
+        private getCompletionEntryDetails(args: protocol.CompletionDetailsRequestArgs, simplifiedResult: boolean): ReadonlyArray<protocol.CompletionEntryDetails> | ReadonlyArray<CompletionEntryDetails> {
             const { file, project } = this.getFileAndProject(args);
             const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(file);
             const position = this.getPosition(args, scriptInfo);
             const formattingOptions = project.projectService.getFormatCodeOptions(file);
 
-            return mapDefined<string | protocol.CompletionEntryIdentifier, protocol.CompletionEntryDetails>(args.entryNames, entryName => {
+            const result = mapDefined(args.entryNames, entryName => {
                 const { name, source } = typeof entryName === "string" ? { name: entryName, source: undefined } : entryName;
-                const details = project.getLanguageService().getCompletionEntryDetails(file, position, name, formattingOptions, source);
-                if (details) {
-                    const mappedCodeActions = map(details.codeActions, action => this.mapCodeAction(action, scriptInfo));
-                    return { ...details, codeActions: mappedCodeActions };
-                }
-                else {
-                    return undefined;
-                }
+                return project.getLanguageService().getCompletionEntryDetails(file, position, name, formattingOptions, source);
             });
+            return simplifiedResult
+                ? result.map(details => ({ ...details, codeActions: map(details.codeActions, action => this.mapCodeAction(action, scriptInfo)) }))
+                : result;
         }
 
         private getCompileOnSaveAffectedFileList(args: protocol.FileRequestArgs): ReadonlyArray<protocol.CompileOnSaveAffectedFileListSingleProject> {
@@ -1337,13 +1349,13 @@ namespace ts.server {
             this.projectService.closeClientFile(file);
         }
 
-        private decorateNavigationBarItems(items: NavigationBarItem[], scriptInfo: ScriptInfo): protocol.NavigationBarItem[] {
+        private mapLocationNavigationBarItems(items: NavigationBarItem[], scriptInfo: ScriptInfo): protocol.NavigationBarItem[] {
             return map(items, item => ({
                 text: item.text,
                 kind: item.kind,
                 kindModifiers: item.kindModifiers,
-                spans: item.spans.map(span => this.decorateSpan(span, scriptInfo)),
-                childItems: this.decorateNavigationBarItems(item.childItems, scriptInfo),
+                spans: item.spans.map(span => this.toLocationTextSpan(span, scriptInfo)),
+                childItems: this.mapLocationNavigationBarItems(item.childItems, scriptInfo),
                 indent: item.indent
             }));
         }
@@ -1354,21 +1366,21 @@ namespace ts.server {
             return !items
                 ? undefined
                 : simplifiedResult
-                    ? this.decorateNavigationBarItems(items, this.projectService.getScriptInfoForNormalizedPath(file))
+                    ? this.mapLocationNavigationBarItems(items, this.projectService.getScriptInfoForNormalizedPath(file))
                     : items;
         }
 
-        private decorateNavigationTree(tree: NavigationTree, scriptInfo: ScriptInfo): protocol.NavigationTree {
+        private toLocationNavigationTree(tree: NavigationTree, scriptInfo: ScriptInfo): protocol.NavigationTree {
             return {
                 text: tree.text,
                 kind: tree.kind,
                 kindModifiers: tree.kindModifiers,
-                spans: tree.spans.map(span => this.decorateSpan(span, scriptInfo)),
-                childItems: map(tree.childItems, item => this.decorateNavigationTree(item, scriptInfo))
+                spans: tree.spans.map(span => this.toLocationTextSpan(span, scriptInfo)),
+                childItems: map(tree.childItems, item => this.toLocationNavigationTree(item, scriptInfo))
             };
         }
 
-        private decorateSpan(span: TextSpan, scriptInfo: ScriptInfo): protocol.TextSpan {
+        private toLocationTextSpan(span: TextSpan, scriptInfo: ScriptInfo): protocol.TextSpan {
             return {
                 start: scriptInfo.positionToLineOffset(span.start),
                 end: scriptInfo.positionToLineOffset(textSpanEnd(span))
@@ -1381,7 +1393,7 @@ namespace ts.server {
             return !tree
                 ? undefined
                 : simplifiedResult
-                    ? this.decorateNavigationTree(tree, this.projectService.getScriptInfoForNormalizedPath(file))
+                    ? this.toLocationNavigationTree(tree, this.projectService.getScriptInfoForNormalizedPath(file))
                     : tree;
         }
 
@@ -1400,14 +1412,12 @@ namespace ts.server {
 
                         return navItems.map((navItem) => {
                             const scriptInfo = project.getScriptInfo(navItem.fileName);
-                            const start = scriptInfo.positionToLineOffset(navItem.textSpan.start);
-                            const end = scriptInfo.positionToLineOffset(textSpanEnd(navItem.textSpan));
                             const bakedItem: protocol.NavtoItem = {
                                 name: navItem.name,
                                 kind: navItem.kind,
                                 file: navItem.fileName,
-                                start,
-                                end,
+                                start: scriptInfo.positionToLineOffset(navItem.textSpan.start),
+                                end: scriptInfo.positionToLineOffset(textSpanEnd(navItem.textSpan))
                             };
                             if (navItem.kindModifiers && (navItem.kindModifiers !== "")) {
                                 bakedItem.kindModifiers = navItem.kindModifiers;
@@ -1594,7 +1604,7 @@ namespace ts.server {
                 fileName: change.fileName,
                 textChanges: change.textChanges.map(textChange => this.convertTextChangeToCodeEdit(textChange, scriptInfo))
             }));
-            return { description,  changes, commands };
+            return { description, changes, commands };
         }
 
         private mapTextChangesToCodeEdits(project: Project, textChanges: FileTextChanges): protocol.FileCodeEdits {
@@ -1622,7 +1632,7 @@ namespace ts.server {
             return !spans
                 ? undefined
                 : simplifiedResult
-                    ? spans.map(span => this.decorateSpan(span, scriptInfo))
+                    ? spans.map(span => this.toLocationTextSpan(span, scriptInfo))
                     : spans;
         }
 
@@ -1677,8 +1687,7 @@ namespace ts.server {
             return normalizePath(name);
         }
 
-        exit() {
-        }
+        exit() { /*overridden*/ }
 
         private notRequired(): HandlerResponse {
             return { responseRequired: false };
@@ -1738,6 +1747,12 @@ namespace ts.server {
             [CommandNames.DefinitionFull]: (request: protocol.DefinitionRequest) => {
                 return this.requiredResponse(this.getDefinition(request.arguments, /*simplifiedResult*/ false));
             },
+            [CommandNames.DefinitionAndBoundSpan]: (request: protocol.DefinitionRequest) => {
+                return this.requiredResponse(this.getDefinitionAndBoundSpan(request.arguments, /*simplifiedResult*/ true));
+            },
+            [CommandNames.DefinitionAndBoundSpanFull]: (request: protocol.DefinitionRequest) => {
+                return this.requiredResponse(this.getDefinitionAndBoundSpan(request.arguments, /*simplifiedResult*/ false));
+            },
             [CommandNames.TypeDefinition]: (request: protocol.FileLocationRequest) => {
                 return this.requiredResponse(this.getTypeDefinition(request.arguments));
             },
@@ -1815,14 +1830,17 @@ namespace ts.server {
             [CommandNames.FormatRangeFull]: (request: protocol.FormatRequest) => {
                 return this.requiredResponse(this.getFormattingEditsForRangeFull(request.arguments));
             },
-            [CommandNames.Completions]: (request: protocol.CompletionDetailsRequest) => {
+            [CommandNames.Completions]: (request: protocol.CompletionsRequest) => {
                 return this.requiredResponse(this.getCompletions(request.arguments, /*simplifiedResult*/ true));
             },
-            [CommandNames.CompletionsFull]: (request: protocol.CompletionDetailsRequest) => {
+            [CommandNames.CompletionsFull]: (request: protocol.CompletionsRequest) => {
                 return this.requiredResponse(this.getCompletions(request.arguments, /*simplifiedResult*/ false));
             },
             [CommandNames.CompletionDetails]: (request: protocol.CompletionDetailsRequest) => {
-                return this.requiredResponse(this.getCompletionEntryDetails(request.arguments));
+                return this.requiredResponse(this.getCompletionEntryDetails(request.arguments, /*simplifiedResult*/ true));
+            },
+            [CommandNames.CompletionDetailsFull]: (request: protocol.CompletionDetailsRequest) => {
+                return this.requiredResponse(this.getCompletionEntryDetails(request.arguments, /*simplifiedResult*/ false));
             },
             [CommandNames.CompileOnSaveAffectedFileList]: (request: protocol.CompileOnSaveAffectedFileListRequest) => {
                 return this.requiredResponse(this.getCompileOnSaveAffectedFileList(request.arguments));
diff --git a/src/server/shared.ts b/src/server/shared.ts
index a8a122c3327..99a38eba389 100644
--- a/src/server/shared.ts
+++ b/src/server/shared.ts
@@ -1,6 +1,7 @@
 /// <reference path="types.ts" />
 
 namespace ts.server {
+    // tslint:disable variable-name
     export const ActionSet: ActionSet = "action::set";
     export const ActionInvalidate: ActionInvalidate = "action::invalidate";
     export const EventTypesRegistry: EventTypesRegistry = "event::typesRegistry";
diff --git a/src/server/typingsCache.ts b/src/server/typingsCache.ts
index d6eeaa2cbcf..cde303bfd39 100644
--- a/src/server/typingsCache.ts
+++ b/src/server/typingsCache.ts
@@ -5,6 +5,7 @@ namespace ts.server {
         projectRootPath: Path;
     }
 
+    // tslint:disable-next-line interface-name (for backwards-compatibility)
     export interface ITypingsInstaller {
         isKnownTypesPackageName(name: string): boolean;
         installPackage(options: InstallPackageOptionsWithProjectRootPath): Promise<ApplyCodeActionCommandResult>;
diff --git a/src/server/typingsInstaller/nodeTypingsInstaller.ts b/src/server/typingsInstaller/nodeTypingsInstaller.ts
index 2a1036010a7..da16d5dde82 100644
--- a/src/server/typingsInstaller/nodeTypingsInstaller.ts
+++ b/src/server/typingsInstaller/nodeTypingsInstaller.ts
@@ -63,9 +63,9 @@ namespace ts.server.typingsInstaller {
         }
     }
 
-    const TypesRegistryPackageName = "types-registry";
+    const typesRegistryPackageName = "types-registry";
     function getTypesRegistryFileLocation(globalTypingsCacheLocation: string): string {
-        return combinePaths(normalizeSlashes(globalTypingsCacheLocation), `node_modules/${TypesRegistryPackageName}/index.json`);
+        return combinePaths(normalizeSlashes(globalTypingsCacheLocation), `node_modules/${typesRegistryPackageName}/index.json`);
     }
 
     interface ExecSyncOptions {
@@ -105,16 +105,16 @@ namespace ts.server.typingsInstaller {
 
             try {
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`Updating ${TypesRegistryPackageName} npm package...`);
+                    this.log.writeLine(`Updating ${typesRegistryPackageName} npm package...`);
                 }
-                this.execSyncAndLog(`${this.npmPath} install --ignore-scripts ${TypesRegistryPackageName}`, { cwd: globalTypingsCacheLocation });
+                this.execSyncAndLog(`${this.npmPath} install --ignore-scripts ${typesRegistryPackageName}`, { cwd: globalTypingsCacheLocation });
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`Updated ${TypesRegistryPackageName} npm package`);
+                    this.log.writeLine(`Updated ${typesRegistryPackageName} npm package`);
                 }
             }
             catch (e) {
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`Error updating ${TypesRegistryPackageName} package: ${(<Error>e).message}`);
+                    this.log.writeLine(`Error updating ${typesRegistryPackageName} package: ${(<Error>e).message}`);
                 }
                 // store error info to report it later when it is known that server is already listening to events from typings installer
                 this.delayedInitializationError = {
@@ -243,7 +243,7 @@ namespace ts.server.typingsInstaller {
     const installer = new NodeTypingsInstaller(globalTypingsCacheLocation, typingSafeListLocation, typesMapLocation, npmLocation, /*throttleLimit*/5, log);
     installer.listen();
 
-    function indent(newline: string, string: string): string {
-        return `${newline}    ` + string.replace(/\r?\n/, `${newline}    `);
+    function indent(newline: string, str: string): string {
+        return `${newline}    ` + str.replace(/\r?\n/, `${newline}    `);
     }
 }
diff --git a/src/server/typingsInstaller/typingsInstaller.ts b/src/server/typingsInstaller/typingsInstaller.ts
index 26e7781b440..eacbebbf4ab 100644
--- a/src/server/typingsInstaller/typingsInstaller.ts
+++ b/src/server/typingsInstaller/typingsInstaller.ts
@@ -248,7 +248,7 @@ namespace ts.server.typingsInstaller {
                     this.log.writeLine(`Npm config file: '${npmConfigPath}' is missing, creating new one...`);
                 }
                 this.ensureDirectoryExists(directory, this.installTypingHost);
-                this.installTypingHost.writeFile(npmConfigPath, "{}");
+                this.installTypingHost.writeFile(npmConfigPath, '{ "private": true }');
             }
         }
 
diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index 69399b672b3..c57d3b40dee 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -19,18 +19,19 @@ namespace ts.server {
         info(s: string): void;
         startGroup(): void;
         endGroup(): void;
-        msg(s: string, type?: Msg.Types): void;
+        msg(s: string, type?: Msg): void;
         getLogFileName(): string;
     }
 
+    // TODO: Use a const enum (https://github.com/Microsoft/TypeScript/issues/16804)
+    export enum Msg {
+        Err = "Err",
+        Info = "Info",
+        Perf = "Perf",
+    }
     export namespace Msg {
-        export type Err = "Err";
-        export const Err: Err = "Err";
-        export type Info = "Info";
-        export const Info: Info = "Info";
-        export type Perf = "Perf";
-        export const Perf: Perf = "Perf";
-        export type Types = Err | Info | Perf;
+        /** @deprecated Only here for backwards-compatibility. Prefer just `Msg`. */
+        export type Types = Msg;
     }
 
     function getProjectRootPath(project: Project): Path {
@@ -250,7 +251,7 @@ namespace ts.server {
             return;
         }
 
-        const insertIndex = binarySearch(array, insert, compare);
+        const insertIndex = binarySearch(array, insert, identity, compare);
         if (insertIndex < 0) {
             array.splice(~insertIndex, 0, insert);
         }
@@ -266,7 +267,7 @@ namespace ts.server {
             return;
         }
 
-        const removeIndex = binarySearch(array, remove, compare);
+        const removeIndex = binarySearch(array, remove, identity, compare);
         if (removeIndex >= 0) {
             array.splice(removeIndex, 1);
         }
@@ -288,8 +289,7 @@ namespace ts.server {
         return index === 0 || value !== array[index - 1];
     }
 
-    export function enumerateInsertsAndDeletes<T>(newItems: SortedReadonlyArray<T>, oldItems: SortedReadonlyArray<T>, inserted: (newItem: T) => void, deleted: (oldItem: T) => void, compare?: Comparer<T>) {
-        compare = compare || compareValues;
+    export function enumerateInsertsAndDeletes<T>(newItems: SortedReadonlyArray<T>, oldItems: SortedReadonlyArray<T>, inserted: (newItem: T) => void, deleted: (oldItem: T) => void, comparer: Comparer<T>) {
         let newIndex = 0;
         let oldIndex = 0;
         const newLen = newItems.length;
@@ -297,7 +297,7 @@ namespace ts.server {
         while (newIndex < newLen && oldIndex < oldLen) {
             const newItem = newItems[newIndex];
             const oldItem = oldItems[oldIndex];
-            const compareResult = compare(newItem, oldItem);
+            const compareResult = comparer(newItem, oldItem);
             if (compareResult === Comparison.LessThan) {
                 inserted(newItem);
                 newIndex++;
@@ -320,8 +320,8 @@ namespace ts.server {
     }
 
     /* @internal */
-    export function indent(string: string): string {
-        return "\n    " + string;
+    export function indent(str: string): string {
+        return "\n    " + str;
     }
 
     /** Put stringified JSON on the next line, indented. */
diff --git a/src/server/watchGuard/watchGuard.ts b/src/server/watchGuard/watchGuard.ts
index f57369aecb9..8ec248ebb87 100644
--- a/src/server/watchGuard/watchGuard.ts
+++ b/src/server/watchGuard/watchGuard.ts
@@ -14,6 +14,5 @@ try {
     const watcher = fs.watch(directoryName, { recursive: true }, () => ({}));
     watcher.close();
 }
-catch (_e) {
-}
+catch { /*ignore*/ }
 process.exit(0);
\ No newline at end of file
diff --git a/src/services/breakpoints.ts b/src/services/breakpoints.ts
index 37aa8df0ca1..73732ce87e8 100644
--- a/src/services/breakpoints.ts
+++ b/src/services/breakpoints.ts
@@ -31,7 +31,7 @@ namespace ts.BreakpointResolver {
         }
 
         // Cannot set breakpoint in ambient declarations
-        if (isInAmbientContext(tokenAtLocation)) {
+        if (tokenAtLocation.flags & NodeFlags.Ambient) {
             return undefined;
         }
 
@@ -297,7 +297,7 @@ namespace ts.BreakpointResolver {
                             }
                         }
 
-                        if (isPartOfExpression(node)) {
+                        if (isExpressionNode(node)) {
                             switch (node.parent.kind) {
                                 case SyntaxKind.DoStatement:
                                     // Set span as if on while keyword
diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index c15ca341cb4..29f2475f21d 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -26,7 +26,7 @@ namespace ts.codefix {
 
         const typesPackageName = getTypesPackageName(packageName);
         return {
-            description: `Install '${typesPackageName}'`,
+            description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Install_0), [typesPackageName]),
             changes: [],
             commands: [{ type: "install package", packageName: typesPackageName }],
         };
diff --git a/src/services/codefixes/fixClassSuperMustPrecedeThisAccess.ts b/src/services/codefixes/fixClassSuperMustPrecedeThisAccess.ts
index bc92cd8e0d1..e5c4266684d 100644
--- a/src/services/codefixes/fixClassSuperMustPrecedeThisAccess.ts
+++ b/src/services/codefixes/fixClassSuperMustPrecedeThisAccess.ts
@@ -20,8 +20,8 @@ namespace ts.codefix {
             // i.e. super(this.a), since in that case we won't suggest a fix
             if (superCall.expression && superCall.expression.kind === SyntaxKind.CallExpression) {
                 const expressionArguments = (<CallExpression>superCall.expression).arguments;
-                for (let i = 0; i < expressionArguments.length; i++) {
-                    if ((<PropertyAccessExpression>expressionArguments[i]).expression === token) {
+                for (const arg of expressionArguments) {
+                    if ((<PropertyAccessExpression>arg).expression === token) {
                         return undefined;
                     }
                 }
diff --git a/src/services/codefixes/fixSpelling.ts b/src/services/codefixes/fixSpelling.ts
index ff3bd455291..2546a92a32f 100644
--- a/src/services/codefixes/fixSpelling.ts
+++ b/src/services/codefixes/fixSpelling.ts
@@ -22,7 +22,9 @@ namespace ts.codefix {
         }
         else {
             const meaning = getMeaningFromLocation(node);
-            suggestion = checker.getSuggestionForNonexistentSymbol(node, getTextOfNode(node), convertSemanticMeaningToSymbolFlags(meaning));
+            const name = getTextOfNode(node);
+            Debug.assert(name !== undefined, "name should be defined");
+            suggestion = checker.getSuggestionForNonexistentSymbol(node, name, convertSemanticMeaningToSymbolFlags(meaning));
         }
         if (suggestion) {
             return [{
diff --git a/src/services/codefixes/helpers.ts b/src/services/codefixes/helpers.ts
index 685c6832f13..206a3864ac0 100644
--- a/src/services/codefixes/helpers.ts
+++ b/src/services/codefixes/helpers.ts
@@ -104,8 +104,7 @@ namespace ts.codefix {
                 }
 
                 const signatureDeclarations: MethodDeclaration[] = [];
-                for (let i = 0; i < signatures.length; i++) {
-                    const signature = signatures[i];
+                for (const signature of signatures) {
                     const methodDeclaration = signatureToMethodDeclaration(signature, enclosingDeclaration);
                     if (methodDeclaration) {
                         signatureDeclarations.push(methodDeclaration);
@@ -194,8 +193,7 @@ namespace ts.codefix {
         let maxArgsSignature = signatures[0];
         let minArgumentCount = signatures[0].minArgumentCount;
         let someSigHasRestParameter = false;
-        for (let i = 0; i < signatures.length; i++) {
-            const sig = signatures[i];
+        for (const sig of signatures) {
             minArgumentCount = Math.min(sig.minArgumentCount, minArgumentCount);
             if (sig.hasRestParameter) {
                 someSigHasRestParameter = true;
diff --git a/src/services/codefixes/importFixes.ts b/src/services/codefixes/importFixes.ts
index 3f0d27e5b07..a0c7ffd75ea 100644
--- a/src/services/codefixes/importFixes.ts
+++ b/src/services/codefixes/importFixes.ts
@@ -166,7 +166,7 @@ namespace ts.codefix {
         return {
             host: context.host,
             newLineCharacter: context.newLineCharacter,
-            rulesProvider: context.rulesProvider,
+            formatContext: context.formatContext,
             sourceFile: context.sourceFile,
             checker,
             compilerOptions: context.program.getCompilerOptions(),
@@ -181,6 +181,7 @@ namespace ts.codefix {
         Named,
         Default,
         Namespace,
+        Equals
     }
 
     export function getCodeActionForImport(moduleSymbol: Symbol, context: ImportCodeFixOptions): ImportCodeAction[] {
@@ -212,7 +213,7 @@ namespace ts.codefix {
 
     function getNamespaceImportName(declaration: AnyImportSyntax): Identifier {
         if (declaration.kind === SyntaxKind.ImportDeclaration) {
-            const namedBindings = declaration.importClause && declaration.importClause.namedBindings;
+            const namedBindings = declaration.importClause && isImportClause(declaration.importClause) && declaration.importClause.namedBindings;
             return namedBindings && namedBindings.kind === SyntaxKind.NamespaceImport ? namedBindings.name : undefined;
         }
         else {
@@ -237,10 +238,12 @@ namespace ts.codefix {
                 return parent as ImportDeclaration;
             case SyntaxKind.ExternalModuleReference:
                 return (parent as ExternalModuleReference).parent;
-            default:
-                Debug.assert(parent.kind === SyntaxKind.ExportDeclaration);
+            case SyntaxKind.ExportDeclaration:
+            case SyntaxKind.CallExpression: // For "require()" calls
                 // Ignore these, can't add imports to them.
                 return undefined;
+            default:
+                Debug.fail();
         }
     }
 
@@ -249,11 +252,19 @@ namespace ts.codefix {
         const lastImportDeclaration = findLast(sourceFile.statements, isAnyImportSyntax);
 
         const moduleSpecifierWithoutQuotes = stripQuotes(moduleSpecifier);
-        const importDecl = createImportDeclaration(
-            /*decorators*/ undefined,
-            /*modifiers*/ undefined,
-            createImportClauseOfKind(kind, symbolName),
-            createStringLiteralWithQuoteStyle(sourceFile, moduleSpecifierWithoutQuotes));
+        const quotedModuleSpecifier = createStringLiteralWithQuoteStyle(sourceFile, moduleSpecifierWithoutQuotes);
+        const importDecl = kind !== ImportKind.Equals
+            ? createImportDeclaration(
+                /*decorators*/ undefined,
+                /*modifiers*/ undefined,
+                createImportClauseOfKind(kind, symbolName),
+                quotedModuleSpecifier)
+            : createImportEqualsDeclaration(
+                /*decorators*/ undefined,
+                /*modifiers*/ undefined,
+                createIdentifier(symbolName),
+                createExternalModuleReference(quotedModuleSpecifier));
+
         const changes = ChangeTracker.with(context, changeTracker => {
             if (lastImportDeclaration) {
                 changeTracker.insertNodeAfter(sourceFile, lastImportDeclaration, importDecl, { suffix: newLineCharacter });
@@ -263,11 +274,17 @@ namespace ts.codefix {
             }
         });
 
+        const actionFormat = kind === ImportKind.Equals
+            ? Diagnostics.Import_0_require_1
+            : kind === ImportKind.Namespace
+                ? Diagnostics.Import_Asterisk_as_0_from_1
+                : Diagnostics.Import_0_from_1;
+
         // if this file doesn't have any import statements, insert an import statement and then insert a new line
         // between the only import statement and user code. Otherwise just insert the statement because chances
         // are there are already a new line seperating code and import statements.
         return createCodeAction(
-            Diagnostics.Import_0_from_1,
+            actionFormat,
             [symbolName, moduleSpecifierWithoutQuotes],
             changes,
             "NewImport",
@@ -282,7 +299,7 @@ namespace ts.codefix {
         return literal;
     }
 
-    function createImportClauseOfKind(kind: ImportKind, symbolName: string) {
+    function createImportClauseOfKind(kind: ImportKind.Default | ImportKind.Named | ImportKind.Namespace, symbolName: string) {
         const id = createIdentifier(symbolName);
         switch (kind) {
             case ImportKind.Default:
@@ -534,7 +551,7 @@ namespace ts.codefix {
         declarations: ReadonlyArray<AnyImportSyntax>): ImportCodeAction {
         const fromExistingImport = firstDefined(declarations, declaration => {
             if (declaration.kind === SyntaxKind.ImportDeclaration && declaration.importClause) {
-                const changes = tryUpdateExistingImport(ctx, declaration.importClause);
+                const changes = tryUpdateExistingImport(ctx, isImportClause(declaration.importClause) && declaration.importClause || undefined);
                 if (changes) {
                     const moduleSpecifierWithoutQuotes = stripQuotes(declaration.moduleSpecifier.getText());
                     return createCodeAction(
@@ -564,9 +581,10 @@ namespace ts.codefix {
         return expression && isStringLiteral(expression) ? expression.text : undefined;
     }
 
-    function tryUpdateExistingImport(context: SymbolContext & { kind: ImportKind }, importClause: ImportClause): FileTextChanges[] | undefined {
+    function tryUpdateExistingImport(context: SymbolContext & { kind: ImportKind }, importClause: ImportClause | ImportEqualsDeclaration): FileTextChanges[] | undefined {
         const { symbolName, sourceFile, kind } = context;
-        const { name, namedBindings } = importClause;
+        const { name } = importClause;
+        const { namedBindings } = importClause.kind !== SyntaxKind.ImportEqualsDeclaration && importClause;
         switch (kind) {
             case ImportKind.Default:
                 return name ? undefined : ChangeTracker.with(context, t =>
@@ -592,6 +610,9 @@ namespace ts.codefix {
                 return namedBindings ? undefined : ChangeTracker.with(context, t =>
                     t.replaceNode(sourceFile, importClause, createImportClause(name, createNamespaceImport(createIdentifier(symbolName)))));
 
+            case ImportKind.Equals:
+                return undefined;
+
             default:
                 Debug.assertNever(kind);
         }
@@ -627,7 +648,7 @@ namespace ts.codefix {
     }
 
     function getActionsForUMDImport(context: ImportCodeFixContext): ImportCodeAction[] {
-        const { checker, symbolToken } = context;
+        const { checker, symbolToken, compilerOptions } = context;
         const umdSymbol = checker.getSymbolAtLocation(symbolToken);
         let symbol: ts.Symbol;
         let symbolName: string;
@@ -644,6 +665,20 @@ namespace ts.codefix {
             Debug.fail("Either the symbol or the JSX namespace should be a UMD global if we got here");
         }
 
+        const allowSyntheticDefaultImports = getAllowSyntheticDefaultImports(compilerOptions);
+
+        // Import a synthetic `default` if enabled.
+        if (allowSyntheticDefaultImports) {
+            return getCodeActionForImport(symbol, { ...context, symbolName, kind: ImportKind.Default });
+        }
+        const moduleKind = getEmitModuleKind(compilerOptions);
+
+        // When a synthetic `default` is unavailable, use `import..require` if the module kind supports it.
+        if (moduleKind === ModuleKind.AMD || moduleKind === ModuleKind.CommonJS || moduleKind === ModuleKind.UMD) {
+            return getCodeActionForImport(symbol, { ...context, symbolName, kind: ImportKind.Equals });
+        }
+
+        // Fall back to the `import * as ns` style import.
         return getCodeActionForImport(symbol, { ...context, symbolName, kind: ImportKind.Namespace });
     }
 
diff --git a/src/services/codefixes/inferFromUsage.ts b/src/services/codefixes/inferFromUsage.ts
index b952cc5a98d..378c73f2f75 100644
--- a/src/services/codefixes/inferFromUsage.ts
+++ b/src/services/codefixes/inferFromUsage.ts
@@ -368,7 +368,7 @@ namespace ts.codefix {
         }
 
         function inferTypeFromContextualType(node: Expression, checker: TypeChecker, usageContext: UsageContext): void {
-            if (isPartOfExpression(node)) {
+            if (isExpressionNode(node)) {
                 addCandidateType(usageContext, checker.getContextualType(node));
             }
         }
diff --git a/src/services/completions.ts b/src/services/completions.ts
index 562cdd5cbb2..f66242ca864 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -28,16 +28,18 @@ namespace ts.Completions {
         sourceFile: SourceFile,
         position: number,
         allSourceFiles: ReadonlyArray<SourceFile>,
+        options: GetCompletionsAtPositionOptions,
     ): CompletionInfo | undefined {
         if (isInReferenceComment(sourceFile, position)) {
-            return PathCompletions.getTripleSlashReferenceCompletion(sourceFile, position, compilerOptions, host);
+            const entries = PathCompletions.getTripleSlashReferenceCompletion(sourceFile, position, compilerOptions, host);
+            return entries && pathCompletionsInfo(entries);
         }
 
         if (isInString(sourceFile, position)) {
             return getStringLiteralCompletionEntries(sourceFile, position, typeChecker, compilerOptions, host, log);
         }
 
-        const completionData = getCompletionData(typeChecker, log, sourceFile, position, allSourceFiles);
+        const completionData = getCompletionData(typeChecker, log, sourceFile, position, allSourceFiles, options);
         if (!completionData) {
             return undefined;
         }
@@ -241,12 +243,17 @@ namespace ts.Completions {
             // a['/*completion position*/']
             return getStringLiteralCompletionEntriesFromElementAccess(node.parent, typeChecker, compilerOptions.target, log);
         }
-        else if (node.parent.kind === SyntaxKind.ImportDeclaration || isExpressionOfExternalModuleImportEqualsDeclaration(node) || isRequireCall(node.parent, /*checkArgumentIsStringLiteral*/ false)) {
+        else if (node.parent.kind === SyntaxKind.ImportDeclaration || node.parent.kind === SyntaxKind.ExportDeclaration
+            || isRequireCall(node.parent, /*checkArgumentIsStringLiteral*/ false) || isImportCall(node.parent)
+            || isExpressionOfExternalModuleImportEqualsDeclaration(node)) {
             // Get all known external module names or complete a path to a module
             // i.e. import * as ns from "/*completion position*/";
+            //      var y = import("/*completion position*/");
             //      import x = require("/*completion position*/");
             //      var y = require("/*completion position*/");
-            return PathCompletions.getStringLiteralCompletionEntriesFromModuleNames(<StringLiteral>node, compilerOptions, host, typeChecker);
+            //      export * from "/*completion position*/";
+            const entries = PathCompletions.getStringLiteralCompletionsFromModuleNames(<StringLiteral>node, compilerOptions, host, typeChecker);
+            return pathCompletionsInfo(entries);
         }
         else if (isEqualityExpression(node.parent)) {
             // Get completions from the type of the other operand
@@ -275,6 +282,18 @@ namespace ts.Completions {
         }
     }
 
+    function pathCompletionsInfo(entries: CompletionEntry[]): CompletionInfo {
+        return {
+            // We don't want the editor to offer any other completions, such as snippets, inside a comment.
+            isGlobalCompletion: false,
+            isMemberCompletion: false,
+            // The user may type in a path that doesn't yet exist, creating a "new identifier"
+            // with respect to the collection of identifiers the server is aware of.
+            isNewIdentifierLocation: true,
+            entries,
+        };
+    }
+
     function getStringLiteralCompletionEntriesFromPropertyAssignment(element: ObjectLiteralElement, typeChecker: TypeChecker, target: ScriptTarget, log: Log): CompletionInfo | undefined {
         const type = typeChecker.getContextualType((<ObjectLiteralExpression>element.parent));
         const entries: CompletionEntry[] = [];
@@ -362,7 +381,7 @@ namespace ts.Completions {
         { name, source }: CompletionEntryIdentifier,
         allSourceFiles: ReadonlyArray<SourceFile>,
     ): { type: "symbol", symbol: Symbol, location: Node, symbolToOriginInfoMap: SymbolOriginInfoMap } | { type: "request", request: Request } | { type: "none" } {
-        const completionData = getCompletionData(typeChecker, log, sourceFile, position, allSourceFiles);
+        const completionData = getCompletionData(typeChecker, log, sourceFile, position, allSourceFiles, { includeExternalModuleExports: true });
         if (!completionData) {
             return { type: "none" };
         }
@@ -396,7 +415,7 @@ namespace ts.Completions {
         entryId: CompletionEntryIdentifier,
         allSourceFiles: ReadonlyArray<SourceFile>,
         host: LanguageServiceHost,
-        rulesProvider: formatting.RulesProvider,
+        formatContext: formatting.FormatContext,
     ): CompletionEntryDetails {
         const { name, source } = entryId;
         // Compute all the completion symbols again.
@@ -417,7 +436,7 @@ namespace ts.Completions {
             }
             case "symbol": {
                 const { symbol, location, symbolToOriginInfoMap } = symbolCompletion;
-                const codeActions = getCompletionEntryCodeActions(symbolToOriginInfoMap, symbol, typeChecker, host, compilerOptions, sourceFile, rulesProvider);
+                const codeActions = getCompletionEntryCodeActions(symbolToOriginInfoMap, symbol, typeChecker, host, compilerOptions, sourceFile, formatContext);
                 const kindModifiers = SymbolDisplay.getSymbolModifiers(symbol);
                 const { displayParts, documentation, symbolKind, tags } = SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, location, location, SemanticMeaning.All);
                 return { name, kindModifiers, kind: symbolKind, displayParts, documentation, tags, codeActions, source: source === undefined ? undefined : [textPart(source)] };
@@ -448,7 +467,7 @@ namespace ts.Completions {
         host: LanguageServiceHost,
         compilerOptions: CompilerOptions,
         sourceFile: SourceFile,
-        rulesProvider: formatting.RulesProvider,
+        formatContext: formatting.FormatContext,
     ): CodeAction[] | undefined {
         const symbolOriginInfo = symbolToOriginInfoMap[getSymbolId(symbol)];
         if (!symbolOriginInfo) {
@@ -462,7 +481,7 @@ namespace ts.Completions {
             newLineCharacter: host.getNewLine(),
             compilerOptions,
             sourceFile,
-            rulesProvider,
+            formatContext,
             symbolName: symbol.name,
             getCanonicalFileName: createGetCanonicalFileName(host.useCaseSensitiveFileNames ? host.useCaseSensitiveFileNames() : false),
             symbolToken: undefined,
@@ -503,6 +522,7 @@ namespace ts.Completions {
         sourceFile: SourceFile,
         position: number,
         allSourceFiles: ReadonlyArray<SourceFile>,
+        options: GetCompletionsAtPositionOptions,
     ): CompletionData | undefined {
         const isJavaScriptFile = isSourceFileJavaScript(sourceFile);
 
@@ -900,7 +920,9 @@ namespace ts.Completions {
             const symbolMeanings = SymbolFlags.Type | SymbolFlags.Value | SymbolFlags.Namespace | SymbolFlags.Alias;
 
             symbols = typeChecker.getSymbolsInScope(scopeNode, symbolMeanings);
-            getSymbolsFromOtherSourceFileExports(symbols, previousToken && isIdentifier(previousToken) ? previousToken.text : "");
+            if (options.includeExternalModuleExports) {
+                getSymbolsFromOtherSourceFileExports(symbols, previousToken && isIdentifier(previousToken) ? previousToken.text : "");
+            }
             filterGlobalCompletion(symbols);
 
             return true;
@@ -1839,6 +1861,18 @@ namespace ts.Completions {
             }
         }
 
+        // If the symbol is for a member of an object type and is the internal name of an ES
+        // symbol, it is not a valid entry. Internal names for ES symbols start with "__@"
+        if (symbol.flags & SymbolFlags.ClassMember) {
+            const escapedName = symbol.escapedName as string;
+            if (escapedName.length >= 3 &&
+                escapedName.charCodeAt(0) === CharacterCodes._ &&
+                escapedName.charCodeAt(1) === CharacterCodes._ &&
+                escapedName.charCodeAt(2) === CharacterCodes.at) {
+                return undefined;
+            }
+        }
+
         return getCompletionEntryDisplayName(name, target, performCharacterChecks, allowStringLiteral);
     }
 
diff --git a/src/services/formatting/formatting.ts b/src/services/formatting/formatting.ts
index 3808cb78940..b8122827491 100644
--- a/src/services/formatting/formatting.ts
+++ b/src/services/formatting/formatting.ts
@@ -1,10 +1,14 @@
-///<reference path='..\services.ts' />
-///<reference path='formattingScanner.ts' />
-///<reference path='rulesProvider.ts' />
-///<reference path='references.ts' />
+/// <reference path="formattingContext.ts" />
+/// <reference path="formattingScanner.ts" />
+/// <reference path="rule.ts" />
+/// <reference path="rulesMap.ts" />
 
 /* @internal */
 namespace ts.formatting {
+    export interface FormatContext {
+        readonly options: ts.FormatCodeSettings;
+        readonly getRule: ts.formatting.RulesMap;
+    }
 
     export interface TextRangeWithKind extends TextRange {
         kind: SyntaxKind;
@@ -67,7 +71,7 @@ namespace ts.formatting {
         delta: number;
     }
 
-    export function formatOnEnter(position: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatOnEnter(position: number, sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         const line = sourceFile.getLineAndCharacterOfPosition(position).line;
         if (line === 0) {
             return [];
@@ -93,15 +97,15 @@ namespace ts.formatting {
             // end value is exclusive so add 1 to the result
             end: endOfFormatSpan + 1
         };
-        return formatSpan(span, sourceFile, options, rulesProvider, FormattingRequestKind.FormatOnEnter);
+        return formatSpan(span, sourceFile, formatContext, FormattingRequestKind.FormatOnEnter);
     }
 
-    export function formatOnSemicolon(position: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatOnSemicolon(position: number, sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         const semicolon = findImmediatelyPrecedingTokenOfKind(position, SyntaxKind.SemicolonToken, sourceFile);
-        return formatNodeLines(findOutermostNodeWithinListLevel(semicolon), sourceFile, options, rulesProvider, FormattingRequestKind.FormatOnSemicolon);
+        return formatNodeLines(findOutermostNodeWithinListLevel(semicolon), sourceFile, formatContext, FormattingRequestKind.FormatOnSemicolon);
     }
 
-    export function formatOnOpeningCurly(position: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatOnOpeningCurly(position: number, sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         const openingCurly = findImmediatelyPrecedingTokenOfKind(position, SyntaxKind.OpenBraceToken, sourceFile);
         if (!openingCurly) {
             return [];
@@ -126,29 +130,29 @@ namespace ts.formatting {
             end: position
         };
 
-        return formatSpan(textRange, sourceFile, options, rulesProvider, FormattingRequestKind.FormatOnOpeningCurlyBrace);
+        return formatSpan(textRange, sourceFile, formatContext, FormattingRequestKind.FormatOnOpeningCurlyBrace);
     }
 
-    export function formatOnClosingCurly(position: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatOnClosingCurly(position: number, sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         const precedingToken = findImmediatelyPrecedingTokenOfKind(position, SyntaxKind.CloseBraceToken, sourceFile);
-        return formatNodeLines(findOutermostNodeWithinListLevel(precedingToken), sourceFile, options, rulesProvider, FormattingRequestKind.FormatOnClosingCurlyBrace);
+        return formatNodeLines(findOutermostNodeWithinListLevel(precedingToken), sourceFile, formatContext, FormattingRequestKind.FormatOnClosingCurlyBrace);
     }
 
-    export function formatDocument(sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatDocument(sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         const span = {
             pos: 0,
             end: sourceFile.text.length
         };
-        return formatSpan(span, sourceFile, options, rulesProvider, FormattingRequestKind.FormatDocument);
+        return formatSpan(span, sourceFile, formatContext, FormattingRequestKind.FormatDocument);
     }
 
-    export function formatSelection(start: number, end: number, sourceFile: SourceFile, rulesProvider: RulesProvider, options: FormatCodeSettings): TextChange[] {
+    export function formatSelection(start: number, end: number, sourceFile: SourceFile, formatContext: FormatContext): TextChange[] {
         // format from the beginning of the line
         const span = {
             pos: getLineStartPositionForPosition(start, sourceFile),
             end,
         };
-        return formatSpan(span, sourceFile, options, rulesProvider, FormattingRequestKind.FormatSelection);
+        return formatSpan(span, sourceFile, formatContext, FormattingRequestKind.FormatSelection);
     }
 
     /**
@@ -337,7 +341,7 @@ namespace ts.formatting {
     }
 
     /* @internal */
-    export function formatNodeGivenIndentation(node: Node, sourceFileLike: SourceFileLike, languageVariant: LanguageVariant, initialIndentation: number, delta: number,  rulesProvider: RulesProvider): TextChange[] {
+    export function formatNodeGivenIndentation(node: Node, sourceFileLike: SourceFileLike, languageVariant: LanguageVariant, initialIndentation: number, delta: number, formatContext: FormatContext): TextChange[] {
         const range = { pos: 0, end: sourceFileLike.text.length };
         return getFormattingScanner(sourceFileLike.text, languageVariant, range.pos, range.end, scanner => formatSpanWorker(
             range,
@@ -345,14 +349,13 @@ namespace ts.formatting {
             initialIndentation,
             delta,
             scanner,
-            rulesProvider.getFormatOptions(),
-            rulesProvider,
+            formatContext,
             FormattingRequestKind.FormatSelection,
             _ => false, // assume that node does not have any errors
             sourceFileLike));
     }
 
-    function formatNodeLines(node: Node, sourceFile: SourceFile, options: FormatCodeSettings, rulesProvider: RulesProvider, requestKind: FormattingRequestKind): TextChange[] {
+    function formatNodeLines(node: Node, sourceFile: SourceFile, formatContext: FormatContext, requestKind: FormattingRequestKind): TextChange[] {
         if (!node) {
             return [];
         }
@@ -362,24 +365,19 @@ namespace ts.formatting {
             end: node.end
         };
 
-        return formatSpan(span, sourceFile, options, rulesProvider, requestKind);
+        return formatSpan(span, sourceFile, formatContext, requestKind);
     }
 
-    function formatSpan(originalRange: TextRange,
-        sourceFile: SourceFile,
-        options: FormatCodeSettings,
-        rulesProvider: RulesProvider,
-        requestKind: FormattingRequestKind): TextChange[] {
+    function formatSpan(originalRange: TextRange, sourceFile: SourceFile, formatContext: FormatContext, requestKind: FormattingRequestKind): TextChange[] {
         // find the smallest node that fully wraps the range and compute the initial indentation for the node
         const enclosingNode = findEnclosingNode(originalRange, sourceFile);
         return getFormattingScanner(sourceFile.text, sourceFile.languageVariant, getScanStartPosition(enclosingNode, originalRange, sourceFile), originalRange.end, scanner => formatSpanWorker(
             originalRange,
             enclosingNode,
-            SmartIndenter.getIndentationForNode(enclosingNode, originalRange, sourceFile, options),
-            getOwnOrInheritedDelta(enclosingNode, options, sourceFile),
+            SmartIndenter.getIndentationForNode(enclosingNode, originalRange, sourceFile, formatContext.options),
+            getOwnOrInheritedDelta(enclosingNode, formatContext.options, sourceFile),
             scanner,
-            options,
-            rulesProvider,
+            formatContext,
             requestKind,
             prepareRangeContainsErrorFunction(sourceFile.parseDiagnostics, originalRange),
             sourceFile));
@@ -390,8 +388,7 @@ namespace ts.formatting {
         initialIndentation: number,
         delta: number,
         formattingScanner: FormattingScanner,
-        options: FormatCodeSettings,
-        rulesProvider: RulesProvider,
+        { options, getRule }: FormatContext,
         requestKind: FormattingRequestKind,
         rangeContainsError: (r: TextRange) => boolean,
         sourceFile: SourceFileLike): TextChange[] {
@@ -714,6 +711,11 @@ namespace ts.formatting {
 
                 processNode(child, childContextNode, childStartLine, undecoratedChildStartLine, childIndentation.indentation, childIndentation.delta);
 
+                if (child.kind === SyntaxKind.JsxText) {
+                    const range: TextRange = { pos: child.getStart(), end: child.getEnd() };
+                    indentMultilineCommentOrJsxText(range, childIndentation.indentation, /*firstLineIsIndented*/ true, /*indentFinalLine*/ false);
+                }
+
                 childContextNode = node;
 
                 if (isFirstListItem && parent.kind === SyntaxKind.ArrayLiteralExpression && inheritedIndentation === Constants.Unknown) {
@@ -833,7 +835,7 @@ namespace ts.formatting {
                             switch (triviaItem.kind) {
                                 case SyntaxKind.MultiLineCommentTrivia:
                                     if (triviaInRange) {
-                                        indentMultilineComment(triviaItem, commentIndentation, /*firstLineIsIndented*/ !indentNextTokenOrTrivia);
+                                        indentMultilineCommentOrJsxText(triviaItem, commentIndentation, /*firstLineIsIndented*/ !indentNextTokenOrTrivia);
                                     }
                                     indentNextTokenOrTrivia = false;
                                     break;
@@ -912,14 +914,14 @@ namespace ts.formatting {
 
             formattingContext.updateContext(previousItem, previousParent, currentItem, currentParent, contextNode);
 
-            const rule = rulesProvider.getRulesMap().GetRule(formattingContext);
+            const rule = getRule(formattingContext);
 
             let trimTrailingWhitespaces: boolean;
             let lineAdded: boolean;
             if (rule) {
                 applyRuleEdits(rule, previousItem, previousStartLine, currentItem, currentStartLine);
 
-                if (rule.Operation.Action & (RuleAction.Space | RuleAction.Delete) && currentStartLine !== previousStartLine) {
+                if (rule.action & (RuleAction.Space | RuleAction.Delete) && currentStartLine !== previousStartLine) {
                     lineAdded = false;
                     // Handle the case where the next line is moved to be the end of this line.
                     // In this case we don't indent the next line in the next pass.
@@ -927,7 +929,7 @@ namespace ts.formatting {
                         dynamicIndentation.recomputeIndentation(/*lineAddedByFormatting*/ false);
                     }
                 }
-                else if (rule.Operation.Action & RuleAction.NewLine && currentStartLine === previousStartLine) {
+                else if (rule.action & RuleAction.NewLine && currentStartLine === previousStartLine) {
                     lineAdded = true;
                     // Handle the case where token2 is moved to the new line.
                     // In this case we indent token2 in the next pass but we set
@@ -938,7 +940,7 @@ namespace ts.formatting {
                 }
 
                 // We need to trim trailing whitespace between the tokens if they were on different lines, and no rule was applied to put them on the same line
-                trimTrailingWhitespaces = !(rule.Operation.Action & RuleAction.Delete) && rule.Flag !== RuleFlags.CanDeleteNewLines;
+                trimTrailingWhitespaces = !(rule.action & RuleAction.Delete) && rule.flags !== RuleFlags.CanDeleteNewLines;
             }
             else {
                 trimTrailingWhitespaces = true;
@@ -985,7 +987,7 @@ namespace ts.formatting {
             return indentationString !== sourceFile.text.substr(startLinePosition, indentationString.length);
         }
 
-        function indentMultilineComment(commentRange: TextRange, indentation: number, firstLineIsIndented: boolean) {
+        function indentMultilineCommentOrJsxText(commentRange: TextRange, indentation: number, firstLineIsIndented: boolean, indentFinalLine = true) {
             // split comment in lines
             let startLine = sourceFile.getLineAndCharacterOfPosition(commentRange.pos).line;
             const endLine = sourceFile.getLineAndCharacterOfPosition(commentRange.end).line;
@@ -1006,7 +1008,9 @@ namespace ts.formatting {
                     startPos = getStartPositionOfLine(line + 1, sourceFile);
                 }
 
-                parts.push({ pos: startPos, end: commentRange.end });
+                if (indentFinalLine) {
+                    parts.push({ pos: startPos, end: commentRange.end });
+                }
             }
 
             const startLinePos = getStartPositionOfLine(startLine, sourceFile);
@@ -1111,7 +1115,7 @@ namespace ts.formatting {
             currentRange: TextRangeWithKind,
             currentStartLine: number): void {
 
-            switch (rule.Operation.Action) {
+            switch (rule.action) {
                 case RuleAction.Ignore:
                     // no action required
                     return;
@@ -1125,7 +1129,7 @@ namespace ts.formatting {
                     // exit early if we on different lines and rule cannot change number of newlines
                     // if line1 and line2 are on subsequent lines then no edits are required - ok to exit
                     // if line1 and line2 are separated with more than one newline - ok to exit since we cannot delete extra new lines
-                    if (rule.Flag !== RuleFlags.CanDeleteNewLines && previousStartLine !== currentStartLine) {
+                    if (rule.flags !== RuleFlags.CanDeleteNewLines && previousStartLine !== currentStartLine) {
                         return;
                     }
 
@@ -1137,7 +1141,7 @@ namespace ts.formatting {
                     break;
                 case RuleAction.Space:
                     // exit early if we on different lines and rule cannot change number of newlines
-                    if (rule.Flag !== RuleFlags.CanDeleteNewLines && previousStartLine !== currentStartLine) {
+                    if (rule.flags !== RuleFlags.CanDeleteNewLines && previousStartLine !== currentStartLine) {
                         return;
                     }
 
diff --git a/src/services/formatting/formattingContext.ts b/src/services/formatting/formattingContext.ts
index 043df72f434..2ba987e4af3 100644
--- a/src/services/formatting/formattingContext.ts
+++ b/src/services/formatting/formattingContext.ts
@@ -1,7 +1,14 @@
-/// <reference path="references.ts"/>
-
 /* @internal */
 namespace ts.formatting {
+    export const enum FormattingRequestKind {
+        FormatDocument,
+        FormatSelection,
+        FormatOnEnter,
+        FormatOnSemicolon,
+        FormatOnOpeningCurlyBrace,
+        FormatOnClosingCurlyBrace
+    }
+
     export class FormattingContext {
         public currentTokenSpan: TextRangeWithKind;
         public nextTokenSpan: TextRangeWithKind;
diff --git a/src/services/formatting/formattingRequestKind.ts b/src/services/formatting/formattingRequestKind.ts
deleted file mode 100644
index 6c671e1b888..00000000000
--- a/src/services/formatting/formattingRequestKind.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-/// <reference path="references.ts"/>
-
-/* @internal */
-namespace ts.formatting {
-    export const enum FormattingRequestKind {
-        FormatDocument,
-        FormatSelection,
-        FormatOnEnter,
-        FormatOnSemicolon,
-        FormatOnOpeningCurlyBrace,
-        FormatOnClosingCurlyBrace
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/references.ts b/src/services/formatting/references.ts
deleted file mode 100644
index 318f10c664e..00000000000
--- a/src/services/formatting/references.ts
+++ /dev/null
@@ -1,12 +0,0 @@
-///<reference path='..\services.ts' />
-///<reference path='formattingContext.ts' />
-///<reference path='formattingRequestKind.ts' />
-///<reference path='rule.ts' />
-///<reference path='ruleAction.ts' />
-///<reference path='ruleDescriptor.ts' />
-///<reference path='ruleFlag.ts' />
-///<reference path='ruleOperation.ts' />
-///<reference path='ruleOperationContext.ts' />
-///<reference path='rules.ts' />
-///<reference path='rulesMap.ts' />
-///<reference path='tokenRange.ts' />
\ No newline at end of file
diff --git a/src/services/formatting/rule.ts b/src/services/formatting/rule.ts
index 10987c745c2..aa1bb6b43e9 100644
--- a/src/services/formatting/rule.ts
+++ b/src/services/formatting/rule.ts
@@ -1,14 +1,30 @@
-///<reference path='references.ts' />
-
 /* @internal */
 namespace ts.formatting {
-    export class Rule {
+    export interface Rule {
         // Used for debugging to identify each rule based on the property name it's assigned to.
-        public debugName?: string;
-        constructor(
-            readonly Descriptor: RuleDescriptor,
-            readonly Operation: RuleOperation,
-            readonly Flag: RuleFlags = RuleFlags.None) {
-        }
+        readonly debugName: string;
+        readonly context: ReadonlyArray<ContextPredicate>;
+        readonly action: RuleAction;
+        readonly flags: RuleFlags;
+    }
+
+    export type ContextPredicate = (context: FormattingContext) => boolean;
+    export const anyContext: ReadonlyArray<ContextPredicate> = emptyArray;
+
+    export const enum RuleAction {
+        Ignore = 1 << 0,
+        Space = 1 << 1,
+        NewLine = 1 << 2,
+        Delete = 1 << 3,
+    }
+
+    export const enum RuleFlags {
+        None,
+        CanDeleteNewLines,
+    }
+
+    export interface TokenRange {
+        readonly tokens: ReadonlyArray<SyntaxKind>;
+        readonly isSpecific: boolean;
     }
 }
\ No newline at end of file
diff --git a/src/services/formatting/ruleAction.ts b/src/services/formatting/ruleAction.ts
deleted file mode 100644
index 13e9043e1c6..00000000000
--- a/src/services/formatting/ruleAction.ts
+++ /dev/null
@@ -1,11 +0,0 @@
-///<reference path='references.ts' />
-
-/* @internal */
-namespace ts.formatting {
-    export const enum RuleAction {
-        Ignore      = 0x00000001,
-        Space       = 0x00000002,
-        NewLine     = 0x00000004,
-        Delete      = 0x00000008
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/ruleDescriptor.ts b/src/services/formatting/ruleDescriptor.ts
deleted file mode 100644
index 96506adc3dc..00000000000
--- a/src/services/formatting/ruleDescriptor.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-///<reference path='references.ts' />
-
-/* @internal */
-namespace ts.formatting {
-    export class RuleDescriptor {
-        constructor(public LeftTokenRange: Shared.TokenRange, public RightTokenRange: Shared.TokenRange) {
-        }
-
-        public toString(): string {
-            return "[leftRange=" + this.LeftTokenRange + "," +
-                "rightRange=" + this.RightTokenRange + "]";
-        }
-
-        static create1(left: SyntaxKind, right: SyntaxKind): RuleDescriptor {
-            return RuleDescriptor.create4(Shared.TokenRange.FromToken(left), Shared.TokenRange.FromToken(right));
-        }
-
-        static create2(left: Shared.TokenRange, right: SyntaxKind): RuleDescriptor {
-            return RuleDescriptor.create4(left, Shared.TokenRange.FromToken(right));
-        }
-
-        static create3(left: SyntaxKind, right: Shared.TokenRange): RuleDescriptor {
-            return RuleDescriptor.create4(Shared.TokenRange.FromToken(left), right);
-        }
-
-        static create4(left: Shared.TokenRange, right: Shared.TokenRange): RuleDescriptor {
-            return new RuleDescriptor(left, right);
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/ruleFlag.ts b/src/services/formatting/ruleFlag.ts
deleted file mode 100644
index 7619f232ad4..00000000000
--- a/src/services/formatting/ruleFlag.ts
+++ /dev/null
@@ -1,10 +0,0 @@
-///<reference path='references.ts' />
-
-
-/* @internal */
-namespace ts.formatting {
-    export const enum RuleFlags {
-        None,
-        CanDeleteNewLines
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/ruleOperation.ts b/src/services/formatting/ruleOperation.ts
deleted file mode 100644
index 8ad83b11653..00000000000
--- a/src/services/formatting/ruleOperation.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-///<reference path='references.ts' />
-
-/* @internal */
-namespace ts.formatting {
-    export class RuleOperation {
-        constructor(public Context: RuleOperationContext, public Action: RuleAction) {}
-
-        public toString(): string {
-            return "[context=" + this.Context + "," +
-                "action=" + this.Action + "]";
-        }
-
-        static create1(action: RuleAction) {
-            return RuleOperation.create2(RuleOperationContext.Any, action);
-        }
-
-        static create2(context: RuleOperationContext, action: RuleAction) {
-            return new RuleOperation(context, action);
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/ruleOperationContext.ts b/src/services/formatting/ruleOperationContext.ts
deleted file mode 100644
index bf96363ad7d..00000000000
--- a/src/services/formatting/ruleOperationContext.ts
+++ /dev/null
@@ -1,32 +0,0 @@
-///<reference path='references.ts' />
-
-/* @internal */
-namespace ts.formatting {
-
-    export class RuleOperationContext {
-        private readonly customContextChecks: { (context: FormattingContext): boolean; }[];
-
-        constructor(...funcs: { (context: FormattingContext): boolean; }[]) {
-            this.customContextChecks = funcs;
-        }
-
-        static readonly Any: RuleOperationContext = new RuleOperationContext();
-
-        public IsAny(): boolean {
-            return this === RuleOperationContext.Any;
-        }
-
-        public InContext(context: FormattingContext): boolean {
-            if (this.IsAny()) {
-                return true;
-            }
-
-            for (const check of this.customContextChecks) {
-                if (!check(context)) {
-                    return false;
-                }
-            }
-            return true;
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/rules.ts b/src/services/formatting/rules.ts
index d41d9dfbfd8..8214ffd6f2d 100644
--- a/src/services/formatting/rules.ts
+++ b/src/services/formatting/rules.ts
@@ -1,928 +1,723 @@
-///<reference path='references.ts' />
-
 /* @internal */
 namespace ts.formatting {
-    export class Rules {
-        public IgnoreBeforeComment: Rule;
-        public IgnoreAfterLineComment: Rule;
+    export interface RuleSpec {
+        readonly leftTokenRange: TokenRange;
+        readonly rightTokenRange: TokenRange;
+        readonly rule: Rule;
+    }
 
-        // Space after keyword but not before ; or : or ?
-        public NoSpaceBeforeSemicolon: Rule;
-        public NoSpaceBeforeColon: Rule;
-        public NoSpaceBeforeQuestionMark: Rule;
-        public SpaceAfterColon: Rule;
-        // insert space after '?' only when it is used in conditional operator
-        public SpaceAfterQuestionMarkInConditionalOperator: Rule;
-        // in other cases there should be no space between '?' and next token
-        public NoSpaceAfterQuestionMark: Rule;
+    export function getAllRules(): RuleSpec[] {
+        const allTokens: SyntaxKind[] = [];
+        for (let token = SyntaxKind.FirstToken; token <= SyntaxKind.LastToken; token++) {
+            allTokens.push(token);
+        }
+        function anyTokenExcept(token: SyntaxKind): TokenRange {
+            return { tokens: allTokens.filter(t => t !== token), isSpecific: false };
+        }
 
-        public SpaceAfterSemicolon: Rule;
+        const anyToken: TokenRange = { tokens: allTokens, isSpecific: false };
+        const anyTokenIncludingMultilineComments = tokenRangeFrom([...allTokens, SyntaxKind.MultiLineCommentTrivia]);
+        const keywords = tokenRangeFromRange(SyntaxKind.FirstKeyword, SyntaxKind.LastKeyword);
+        const binaryOperators = tokenRangeFromRange(SyntaxKind.FirstBinaryOperator, SyntaxKind.LastBinaryOperator);
+        const binaryKeywordOperators = [SyntaxKind.InKeyword, SyntaxKind.InstanceOfKeyword, SyntaxKind.OfKeyword, SyntaxKind.AsKeyword, SyntaxKind.IsKeyword];
+        const unaryPrefixOperators = [SyntaxKind.PlusPlusToken, SyntaxKind.MinusMinusToken, SyntaxKind.TildeToken, SyntaxKind.ExclamationToken];
+        const unaryPrefixExpressions = [
+            SyntaxKind.NumericLiteral, SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken,
+            SyntaxKind.OpenBraceToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword];
+        const unaryPreincrementExpressions = [SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword];
+        const unaryPostincrementExpressions = [SyntaxKind.Identifier, SyntaxKind.CloseParenToken, SyntaxKind.CloseBracketToken, SyntaxKind.NewKeyword];
+        const unaryPredecrementExpressions = [SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword];
+        const unaryPostdecrementExpressions = [SyntaxKind.Identifier, SyntaxKind.CloseParenToken, SyntaxKind.CloseBracketToken, SyntaxKind.NewKeyword];
+        const comments = [SyntaxKind.SingleLineCommentTrivia, SyntaxKind.MultiLineCommentTrivia];
+        const typeNames = [SyntaxKind.Identifier, ...typeKeywords];
 
-        // Space/new line after }.
-        public SpaceAfterCloseBrace: Rule;
-
-        // Special case for (}, else) and (}, while) since else & while tokens are not part of the tree which makes SpaceAfterCloseBrace rule not applied
-        // Also should not apply to })
-        public SpaceBetweenCloseBraceAndElse: Rule;
-        public SpaceBetweenCloseBraceAndWhile: Rule;
-        public NoSpaceAfterCloseBrace: Rule;
-
-        // No space for dot
-        public NoSpaceBeforeDot: Rule;
-        public NoSpaceAfterDot: Rule;
-
-        // No space before and after indexer
-        public NoSpaceBeforeOpenBracket: Rule;
-        public NoSpaceAfterCloseBracket: Rule;
-
-        // Insert a space after { and before } in single-line contexts, but remove space from empty object literals {}.
-        public SpaceAfterOpenBrace: Rule;
-        public SpaceBeforeCloseBrace: Rule;
-        public NoSpaceAfterOpenBrace: Rule;
-        public NoSpaceBeforeCloseBrace: Rule;
-        public NoSpaceBetweenEmptyBraceBrackets: Rule;
-
-        // Insert new line after { and before } in multi-line contexts.
-        public NewLineAfterOpenBraceInBlockContext: Rule;
-
-        // For functions and control block place } on a new line    [multi-line rule]
-        public NewLineBeforeCloseBraceInBlockContext: Rule;
-
-        // Special handling of unary operators.
-        // Prefix operators generally shouldn't have a space between
-        // them and their target unary expression.
-        public NoSpaceAfterUnaryPrefixOperator: Rule;
-        public NoSpaceAfterUnaryPreincrementOperator: Rule;
-        public NoSpaceAfterUnaryPredecrementOperator: Rule;
-        public NoSpaceBeforeUnaryPostincrementOperator: Rule;
-        public NoSpaceBeforeUnaryPostdecrementOperator: Rule;
-
-        // More unary operator special-casing.
-        // DevDiv 181814:  Be careful when removing leading whitespace
-        // around unary operators.  Examples:
-        //      1 - -2  --X-->  1--2
-        //      a + ++b --X-->  a+++b
-        public SpaceAfterPostincrementWhenFollowedByAdd: Rule;
-        public SpaceAfterAddWhenFollowedByUnaryPlus: Rule;
-        public SpaceAfterAddWhenFollowedByPreincrement: Rule;
-        public SpaceAfterPostdecrementWhenFollowedBySubtract: Rule;
-        public SpaceAfterSubtractWhenFollowedByUnaryMinus: Rule;
-        public SpaceAfterSubtractWhenFollowedByPredecrement: Rule;
-
-        public NoSpaceBeforeComma: Rule;
-
-        public SpaceAfterCertainKeywords: Rule;
-        public NoSpaceAfterNewKeywordOnConstructorSignature: Rule;
-        public SpaceAfterLetConstInVariableDeclaration: Rule;
-        public NoSpaceBeforeOpenParenInFuncCall: Rule;
-        public SpaceAfterFunctionInFuncDecl: Rule;
-        public SpaceBeforeOpenParenInFuncDecl: Rule;
-        public NoSpaceBeforeOpenParenInFuncDecl: Rule;
-        public SpaceAfterVoidOperator: Rule;
-
-        public NoSpaceBetweenReturnAndSemicolon: Rule;
-
-        // Add a space between statements. All keywords except (do,else,case) has open/close parens after them.
-        // So, we have a rule to add a space for [),Any], [do,Any], [else,Any], and [case,Any]
-        public SpaceBetweenStatements: Rule;
-
-        // This low-pri rule takes care of "try {" and "finally {" in case the rule SpaceBeforeOpenBraceInControl didn't execute on FormatOnEnter.
-        public SpaceAfterTryFinally: Rule;
-
-        // For get/set members, we check for (identifier,identifier) since get/set don't have tokens and they are represented as just an identifier token.
-        // Though, we do extra check on the context to make sure we are dealing with get/set node. Example:
-        //      get x() {}
-        //      set x(val) {}
-        public SpaceAfterGetSetInMember: Rule;
-
-        // Special case for binary operators (that are keywords). For these we have to add a space and shouldn't follow any user options.
-        public SpaceBeforeBinaryKeywordOperator: Rule;
-        public SpaceAfterBinaryKeywordOperator: Rule;
-
-        // TypeScript-specific rules
-
-        // Treat constructor as an identifier in a function declaration, and remove spaces between constructor and following left parentheses
-        public SpaceAfterConstructor: Rule;
-        public NoSpaceAfterConstructor: Rule;
-
-        // Use of module as a function call. e.g.: import m2 = module("m2");
-        public NoSpaceAfterModuleImport: Rule;
-
-        // Add a space around certain TypeScript keywords
-        public SpaceAfterCertainTypeScriptKeywords: Rule;
-        public SpaceBeforeCertainTypeScriptKeywords: Rule;
-
-        // Treat string literals in module names as identifiers, and add a space between the literal and the opening Brace braces, e.g.: module "m2" {
-        public SpaceAfterModuleName: Rule;
-
-        // Lambda expressions
-        public SpaceBeforeArrow: Rule;
-        public SpaceAfterArrow: Rule;
-
-        // Optional parameters and let args
-        public NoSpaceAfterEllipsis: Rule;
-        public NoSpaceAfterOptionalParameters: Rule;
-
-        // generics
-        public NoSpaceBeforeOpenAngularBracket: Rule;
-        public NoSpaceBetweenCloseParenAndAngularBracket: Rule;
-        public NoSpaceAfterOpenAngularBracket: Rule;
-        public NoSpaceBeforeCloseAngularBracket: Rule;
-        public NoSpaceAfterCloseAngularBracket: Rule;
-
-        // Remove spaces in empty interface literals. e.g.: x: {}
-        public NoSpaceBetweenEmptyInterfaceBraceBrackets: Rule;
-
-        // These rules are higher in priority than user-configurable rules.
-        public HighPriorityCommonRules: Rule[];
-
-        // These rules are applied after high priority rules.
-        public UserConfigurableRules: Rule[];
-
-        // These rules are lower in priority than user-configurable rules.
-        public LowPriorityCommonRules: Rule[];
-
-        ///
-        /// Rules controlled by user options
-        ///
-
-        // Insert space after comma delimiter
-        public SpaceAfterComma: Rule;
-        public NoSpaceAfterComma: Rule;
-
-        // Insert space before and after binary operators
-        public SpaceBeforeBinaryOperator: Rule;
-        public SpaceAfterBinaryOperator: Rule;
-        public NoSpaceBeforeBinaryOperator: Rule;
-        public NoSpaceAfterBinaryOperator: Rule;
-
-        // Insert space after keywords in control flow statements
-        public SpaceAfterKeywordInControl: Rule;
-        public NoSpaceAfterKeywordInControl: Rule;
-
-        // Open Brace braces after function
+        // Place a space before open brace in a function declaration
         // TypeScript: Function can have return types, which can be made of tons of different token kinds
-        public FunctionOpenBraceLeftTokenRange: Shared.TokenRange;
-        public SpaceBeforeOpenBraceInFunction: Rule;
-        public NewLineBeforeOpenBraceInFunction: Rule;
+        const functionOpenBraceLeftTokenRange = anyTokenIncludingMultilineComments;
 
-        // Open Brace braces after TypeScript module/class/interface
-        public TypeScriptOpenBraceLeftTokenRange: Shared.TokenRange;
-        public SpaceBeforeOpenBraceInTypeScriptDeclWithBlock: Rule;
-        public NewLineBeforeOpenBraceInTypeScriptDeclWithBlock: Rule;
+        // Place a space before open brace in a TypeScript declaration that has braces as children (class, module, enum, etc)
+        const typeScriptOpenBraceLeftTokenRange = tokenRangeFrom([SyntaxKind.Identifier, SyntaxKind.MultiLineCommentTrivia, SyntaxKind.ClassKeyword, SyntaxKind.ExportKeyword, SyntaxKind.ImportKeyword]);
 
-        // Open Brace braces after control block
-        public ControlOpenBraceLeftTokenRange: Shared.TokenRange;
-        public SpaceBeforeOpenBraceInControl: Rule;
-        public NewLineBeforeOpenBraceInControl: Rule;
-
-        // Insert space after semicolon in for statement
-        public SpaceAfterSemicolonInFor: Rule;
-        public NoSpaceAfterSemicolonInFor: Rule;
-
-        // Insert space after opening and before closing nonempty parenthesis
-        public SpaceAfterOpenParen: Rule;
-        public SpaceBeforeCloseParen: Rule;
-        public SpaceBetweenOpenParens: Rule;
-        public NoSpaceBetweenParens: Rule;
-        public NoSpaceAfterOpenParen: Rule;
-        public NoSpaceBeforeCloseParen: Rule;
-
-        // Insert space after opening and before closing nonempty brackets
-        public SpaceAfterOpenBracket: Rule;
-        public SpaceBeforeCloseBracket: Rule;
-        public NoSpaceBetweenBrackets: Rule;
-        public NoSpaceAfterOpenBracket: Rule;
-        public NoSpaceBeforeCloseBracket: Rule;
-
-        // Insert space after function keyword for anonymous functions
-        public SpaceAfterAnonymousFunctionKeyword: Rule;
-        public NoSpaceAfterAnonymousFunctionKeyword: Rule;
-
-        // Insert space after @ in decorator
-        public SpaceBeforeAt: Rule;
-        public NoSpaceAfterAt: Rule;
-        public SpaceAfterDecorator: Rule;
-
-        // Generator: function*
-        public NoSpaceBetweenFunctionKeywordAndStar: Rule;
-        public SpaceAfterStarInGeneratorDeclaration: Rule;
-        public NoSpaceBetweenYieldKeywordAndStar: Rule;
-        public SpaceBetweenYieldOrYieldStarAndOperand: Rule;
-
-        // Async functions
-        public SpaceBetweenAsyncAndOpenParen: Rule;
-        public SpaceBetweenAsyncAndFunctionKeyword: Rule;
-
-        // Template strings
-        public NoSpaceBetweenTagAndTemplateString: Rule;
-        public NoSpaceAfterTemplateHeadAndMiddle: Rule;
-        public SpaceAfterTemplateHeadAndMiddle: Rule;
-        public NoSpaceBeforeTemplateMiddleAndTail: Rule;
-        public SpaceBeforeTemplateMiddleAndTail: Rule;
-
-        // No space after { and before } in JSX expression
-        public NoSpaceAfterOpenBraceInJsxExpression: Rule;
-        public SpaceAfterOpenBraceInJsxExpression: Rule;
-        public NoSpaceBeforeCloseBraceInJsxExpression: Rule;
-        public SpaceBeforeCloseBraceInJsxExpression: Rule;
-
-        // JSX opening elements
-        public SpaceBeforeJsxAttribute: Rule;
-        public SpaceBeforeSlashInJsxOpeningElement: Rule;
-        public NoSpaceBeforeGreaterThanTokenInJsxOpeningElement: Rule;
-        public NoSpaceBeforeEqualInJsxAttribute: Rule;
-        public NoSpaceAfterEqualInJsxAttribute: Rule;
-
-        // No space after type assertions
-        public NoSpaceAfterTypeAssertion: Rule;
-        public SpaceAfterTypeAssertion: Rule;
-
-        // No space before non-null assertion operator
-        public NoSpaceBeforeNonNullAssertionOperator: Rule;
-
-        constructor() {
-            ///
-            /// Common Rules
-            ///
+        // Place a space before open brace in a control flow construct
+        const controlOpenBraceLeftTokenRange = tokenRangeFrom([SyntaxKind.CloseParenToken, SyntaxKind.MultiLineCommentTrivia, SyntaxKind.DoKeyword, SyntaxKind.TryKeyword, SyntaxKind.FinallyKeyword, SyntaxKind.ElseKeyword]);
 
+        // These rules are higher in priority than user-configurable
+        const highPriorityCommonRules = [
             // Leave comments alone
-            this.IgnoreBeforeComment = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.Comments), RuleOperation.create1(RuleAction.Ignore));
-            this.IgnoreAfterLineComment = new Rule(RuleDescriptor.create3(SyntaxKind.SingleLineCommentTrivia, Shared.TokenRange.Any), RuleOperation.create1(RuleAction.Ignore));
+            rule("IgnoreBeforeComment", anyToken, comments, anyContext, RuleAction.Ignore),
+            rule("IgnoreAfterLineComment", SyntaxKind.SingleLineCommentTrivia, anyToken, anyContext, RuleAction.Ignore),
 
-            // Space after keyword but not before ; or : or ?
-            this.NoSpaceBeforeSemicolon = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.SemicolonToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeColon = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.ColonToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBinaryOpContext), RuleAction.Delete));
-            this.NoSpaceBeforeQuestionMark = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.QuestionToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBinaryOpContext), RuleAction.Delete));
-            this.SpaceAfterColon = new Rule(RuleDescriptor.create3(SyntaxKind.ColonToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterQuestionMarkInConditionalOperator = new Rule(RuleDescriptor.create3(SyntaxKind.QuestionToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsConditionalOperatorContext), RuleAction.Space));
-            this.NoSpaceAfterQuestionMark = new Rule(RuleDescriptor.create3(SyntaxKind.QuestionToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.SpaceAfterSemicolon = new Rule(RuleDescriptor.create3(SyntaxKind.SemicolonToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
+            rule("NoSpaceBeforeColon", anyToken, SyntaxKind.ColonToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
+            rule("SpaceAfterColon", SyntaxKind.ColonToken, anyToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Space),
+            rule("NoSpaceBeforeQuestionMark", anyToken, SyntaxKind.QuestionToken, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
+            // insert space after '?' only when it is used in conditional operator
+            rule("SpaceAfterQuestionMarkInConditionalOperator", SyntaxKind.QuestionToken, anyToken, [isNonJsxSameLineTokenContext, isConditionalOperatorContext], RuleAction.Space),
 
-            // Space after }.
-            this.SpaceAfterCloseBrace = new Rule(RuleDescriptor.create3(SyntaxKind.CloseBraceToken, Shared.TokenRange.FromRange(SyntaxKind.FirstToken, SyntaxKind.LastToken, [SyntaxKind.CloseParenToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsAfterCodeBlockContext), RuleAction.Space));
+            // in other cases there should be no space between '?' and next token
+            rule("NoSpaceAfterQuestionMark", SyntaxKind.QuestionToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
-            // Special case for (}, else) and (}, while) since else & while tokens are not part of the tree which makes SpaceAfterCloseBrace rule not applied
-            this.SpaceBetweenCloseBraceAndElse = new Rule(RuleDescriptor.create1(SyntaxKind.CloseBraceToken, SyntaxKind.ElseKeyword), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBetweenCloseBraceAndWhile = new Rule(RuleDescriptor.create1(SyntaxKind.CloseBraceToken, SyntaxKind.WhileKeyword), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceAfterCloseBrace = new Rule(RuleDescriptor.create3(SyntaxKind.CloseBraceToken, Shared.TokenRange.FromTokens([SyntaxKind.CloseBracketToken, SyntaxKind.CommaToken, SyntaxKind.SemicolonToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-
-            // No space for dot
-            this.NoSpaceBeforeDot = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.DotToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterDot = new Rule(RuleDescriptor.create3(SyntaxKind.DotToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-
-            // No space before and after indexer
-            this.NoSpaceBeforeOpenBracket = new Rule(
-                RuleDescriptor.create2(Shared.TokenRange.AnyExcept(SyntaxKind.AsyncKeyword), SyntaxKind.OpenBracketToken),
-                RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterCloseBracket = new Rule(RuleDescriptor.create3(SyntaxKind.CloseBracketToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBeforeBlockInFunctionDeclarationContext), RuleAction.Delete));
-
-            // Place a space before open brace in a function declaration
-            this.FunctionOpenBraceLeftTokenRange = Shared.TokenRange.AnyIncludingMultilineComments;
-            this.SpaceBeforeOpenBraceInFunction = new Rule(RuleDescriptor.create2(this.FunctionOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForFunctions"), Rules.IsFunctionDeclContext, Rules.IsBeforeBlockContext, Rules.IsNotFormatOnEnter, Rules.IsSameLineTokenOrBeforeBlockContext), RuleAction.Space), RuleFlags.CanDeleteNewLines);
-
-            // Place a space before open brace in a TypeScript declaration that has braces as children (class, module, enum, etc)
-            this.TypeScriptOpenBraceLeftTokenRange = Shared.TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.MultiLineCommentTrivia, SyntaxKind.ClassKeyword, SyntaxKind.ExportKeyword, SyntaxKind.ImportKeyword]);
-            this.SpaceBeforeOpenBraceInTypeScriptDeclWithBlock = new Rule(RuleDescriptor.create2(this.TypeScriptOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForFunctions"), Rules.IsTypeScriptDeclWithBlockContext, Rules.IsNotFormatOnEnter, Rules.IsSameLineTokenOrBeforeBlockContext), RuleAction.Space), RuleFlags.CanDeleteNewLines);
-
-            // Place a space before open brace in a control flow construct
-            this.ControlOpenBraceLeftTokenRange = Shared.TokenRange.FromTokens([SyntaxKind.CloseParenToken, SyntaxKind.MultiLineCommentTrivia, SyntaxKind.DoKeyword, SyntaxKind.TryKeyword, SyntaxKind.FinallyKeyword, SyntaxKind.ElseKeyword]);
-            this.SpaceBeforeOpenBraceInControl = new Rule(RuleDescriptor.create2(this.ControlOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForControlBlocks"), Rules.IsControlDeclContext, Rules.IsNotFormatOnEnter, Rules.IsSameLineTokenOrBeforeBlockContext), RuleAction.Space), RuleFlags.CanDeleteNewLines);
-
-            // Insert a space after { and before } in single-line contexts, but remove space from empty object literals {}.
-            this.SpaceAfterOpenBrace = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBraceToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), Rules.IsBraceWrappedContext), RuleAction.Space));
-            this.SpaceBeforeCloseBrace = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), Rules.IsBraceWrappedContext), RuleAction.Space));
-            this.NoSpaceAfterOpenBrace = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBraceToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeCloseBrace = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBetweenEmptyBraceBrackets = new Rule(RuleDescriptor.create1(SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsObjectContext), RuleAction.Delete));
-
-            // Insert new line after { and before } in multi-line contexts.
-            this.NewLineAfterOpenBraceInBlockContext = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBraceToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsMultilineBlockContext), RuleAction.NewLine));
-
-            // For functions and control block place } on a new line    [multi-line rule]
-            this.NewLineBeforeCloseBraceInBlockContext = new Rule(RuleDescriptor.create2(Shared.TokenRange.AnyIncludingMultilineComments, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsMultilineBlockContext), RuleAction.NewLine));
+            rule("NoSpaceBeforeDot", anyToken, SyntaxKind.DotToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterDot", SyntaxKind.DotToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
             // Special handling of unary operators.
             // Prefix operators generally shouldn't have a space between
             // them and their target unary expression.
-            this.NoSpaceAfterUnaryPrefixOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.UnaryPrefixOperators, Shared.TokenRange.UnaryPrefixExpressions), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBinaryOpContext), RuleAction.Delete));
-            this.NoSpaceAfterUnaryPreincrementOperator = new Rule(RuleDescriptor.create3(SyntaxKind.PlusPlusToken, Shared.TokenRange.UnaryPreincrementExpressions), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterUnaryPredecrementOperator = new Rule(RuleDescriptor.create3(SyntaxKind.MinusMinusToken, Shared.TokenRange.UnaryPredecrementExpressions), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeUnaryPostincrementOperator = new Rule(RuleDescriptor.create2(Shared.TokenRange.UnaryPostincrementExpressions, SyntaxKind.PlusPlusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeUnaryPostdecrementOperator = new Rule(RuleDescriptor.create2(Shared.TokenRange.UnaryPostdecrementExpressions, SyntaxKind.MinusMinusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("NoSpaceAfterUnaryPrefixOperator", unaryPrefixOperators, unaryPrefixExpressions, [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
+            rule("NoSpaceAfterUnaryPreincrementOperator", SyntaxKind.PlusPlusToken, unaryPreincrementExpressions, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterUnaryPredecrementOperator", SyntaxKind.MinusMinusToken, unaryPredecrementExpressions, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeUnaryPostincrementOperator", unaryPostincrementExpressions, SyntaxKind.PlusPlusToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeUnaryPostdecrementOperator", unaryPostdecrementExpressions, SyntaxKind.MinusMinusToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
             // More unary operator special-casing.
             // DevDiv 181814:  Be careful when removing leading whitespace
             // around unary operators.  Examples:
             //      1 - -2  --X-->  1--2
             //      a + ++b --X-->  a+++b
-            this.SpaceAfterPostincrementWhenFollowedByAdd = new Rule(RuleDescriptor.create1(SyntaxKind.PlusPlusToken, SyntaxKind.PlusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterAddWhenFollowedByUnaryPlus = new Rule(RuleDescriptor.create1(SyntaxKind.PlusToken, SyntaxKind.PlusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterAddWhenFollowedByPreincrement = new Rule(RuleDescriptor.create1(SyntaxKind.PlusToken, SyntaxKind.PlusPlusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterPostdecrementWhenFollowedBySubtract = new Rule(RuleDescriptor.create1(SyntaxKind.MinusMinusToken, SyntaxKind.MinusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterSubtractWhenFollowedByUnaryMinus = new Rule(RuleDescriptor.create1(SyntaxKind.MinusToken, SyntaxKind.MinusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterSubtractWhenFollowedByPredecrement = new Rule(RuleDescriptor.create1(SyntaxKind.MinusToken, SyntaxKind.MinusMinusToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
+            rule("SpaceAfterPostincrementWhenFollowedByAdd", SyntaxKind.PlusPlusToken, SyntaxKind.PlusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterAddWhenFollowedByUnaryPlus", SyntaxKind.PlusToken, SyntaxKind.PlusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterAddWhenFollowedByPreincrement", SyntaxKind.PlusToken, SyntaxKind.PlusPlusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterPostdecrementWhenFollowedBySubtract", SyntaxKind.MinusMinusToken, SyntaxKind.MinusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterSubtractWhenFollowedByUnaryMinus", SyntaxKind.MinusToken, SyntaxKind.MinusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterSubtractWhenFollowedByPredecrement", SyntaxKind.MinusToken, SyntaxKind.MinusMinusToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
 
-            this.NoSpaceBeforeComma = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CommaToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("NoSpaceAfterCloseBrace", SyntaxKind.CloseBraceToken, [SyntaxKind.CloseBracketToken, SyntaxKind.CommaToken, SyntaxKind.SemicolonToken], [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            // For functions and control block place } on a new line [multi-line rule]
+            rule("NewLineBeforeCloseBraceInBlockContext", anyTokenIncludingMultilineComments, SyntaxKind.CloseBraceToken, [isMultilineBlockContext], RuleAction.NewLine),
 
-            this.SpaceAfterCertainKeywords = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.VarKeyword, SyntaxKind.ThrowKeyword, SyntaxKind.NewKeyword, SyntaxKind.DeleteKeyword, SyntaxKind.ReturnKeyword, SyntaxKind.TypeOfKeyword, SyntaxKind.AwaitKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceAfterNewKeywordOnConstructorSignature = new Rule(RuleDescriptor.create1(SyntaxKind.NewKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsConstructorSignatureContext), RuleAction.Delete));
-            this.SpaceAfterLetConstInVariableDeclaration = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.LetKeyword, SyntaxKind.ConstKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsStartOfVariableDeclarationList), RuleAction.Space));
-            this.NoSpaceBeforeOpenParenInFuncCall = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionCallOrNewContext, Rules.IsPreviousTokenNotComma), RuleAction.Delete));
-            this.SpaceAfterFunctionInFuncDecl = new Rule(RuleDescriptor.create3(SyntaxKind.FunctionKeyword, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclContext), RuleAction.Space));
-            this.SpaceBeforeOpenParenInFuncDecl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceBeforeFunctionParenthesis"), Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionDeclContext), RuleAction.Space));
-            this.NoSpaceBeforeOpenParenInFuncDecl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceBeforeFunctionParenthesis"), Rules.IsNonJsxSameLineTokenContext, Rules.IsFunctionDeclContext), RuleAction.Delete));
-            this.SpaceAfterVoidOperator = new Rule(RuleDescriptor.create3(SyntaxKind.VoidKeyword, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsVoidOpContext), RuleAction.Space));
+            // Space/new line after }.
+            rule("SpaceAfterCloseBrace", SyntaxKind.CloseBraceToken, anyTokenExcept(SyntaxKind.CloseParenToken), [isNonJsxSameLineTokenContext, isAfterCodeBlockContext], RuleAction.Space),
+            // Special case for (}, else) and (}, while) since else & while tokens are not part of the tree which makes SpaceAfterCloseBrace rule not applied
+            // Also should not apply to })
+            rule("SpaceBetweenCloseBraceAndElse", SyntaxKind.CloseBraceToken, SyntaxKind.ElseKeyword, [isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBetweenCloseBraceAndWhile", SyntaxKind.CloseBraceToken, SyntaxKind.WhileKeyword, [isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceBetweenEmptyBraceBrackets", SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken, [isNonJsxSameLineTokenContext, isObjectContext], RuleAction.Delete),
 
-            this.NoSpaceBetweenReturnAndSemicolon = new Rule(RuleDescriptor.create1(SyntaxKind.ReturnKeyword, SyntaxKind.SemicolonToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("NoSpaceBetweenFunctionKeywordAndStar", SyntaxKind.FunctionKeyword, SyntaxKind.AsteriskToken, [isFunctionDeclarationOrFunctionExpressionContext], RuleAction.Delete),
+            rule("SpaceAfterStarInGeneratorDeclaration", SyntaxKind.AsteriskToken, [SyntaxKind.Identifier, SyntaxKind.OpenParenToken], [isFunctionDeclarationOrFunctionExpressionContext], RuleAction.Space),
 
-            // Add a space between statements. All keywords except (do,else,case) has open/close parens after them.
-            // So, we have a rule to add a space for [),Any], [do,Any], [else,Any], and [case,Any]
-            this.SpaceBetweenStatements = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.CloseParenToken, SyntaxKind.DoKeyword, SyntaxKind.ElseKeyword, SyntaxKind.CaseKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNonJsxElementContext, Rules.IsNotForContext), RuleAction.Space));
-
-            // This low-pri rule takes care of "try {" and "finally {" in case the rule SpaceBeforeOpenBraceInControl didn't execute on FormatOnEnter.
-            this.SpaceAfterTryFinally = new Rule(RuleDescriptor.create2(Shared.TokenRange.FromTokens([SyntaxKind.TryKeyword, SyntaxKind.FinallyKeyword]), SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
+            rule("SpaceAfterFunctionInFuncDecl", SyntaxKind.FunctionKeyword, anyToken, [isFunctionDeclContext], RuleAction.Space),
+            // Insert new line after { and before } in multi-line contexts.
+            rule("NewLineAfterOpenBraceInBlockContext", SyntaxKind.OpenBraceToken, anyToken, [isMultilineBlockContext], RuleAction.NewLine),
 
+            // For get/set members, we check for (identifier,identifier) since get/set don't have tokens and they are represented as just an identifier token.
+            // Though, we do extra check on the context to make sure we are dealing with get/set node. Example:
             //      get x() {}
             //      set x(val) {}
-            this.SpaceAfterGetSetInMember = new Rule(RuleDescriptor.create2(Shared.TokenRange.FromTokens([SyntaxKind.GetKeyword, SyntaxKind.SetKeyword]), SyntaxKind.Identifier), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclContext), RuleAction.Space));
+            rule("SpaceAfterGetSetInMember", [SyntaxKind.GetKeyword, SyntaxKind.SetKeyword], SyntaxKind.Identifier, [isFunctionDeclContext], RuleAction.Space),
+
+            rule("NoSpaceBetweenYieldKeywordAndStar", SyntaxKind.YieldKeyword, SyntaxKind.AsteriskToken, [isNonJsxSameLineTokenContext, isYieldOrYieldStarWithOperand], RuleAction.Delete),
+            rule("SpaceBetweenYieldOrYieldStarAndOperand", [SyntaxKind.YieldKeyword, SyntaxKind.AsteriskToken], anyToken, [isNonJsxSameLineTokenContext, isYieldOrYieldStarWithOperand], RuleAction.Space),
+
+            rule("NoSpaceBetweenReturnAndSemicolon", SyntaxKind.ReturnKeyword, SyntaxKind.SemicolonToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("SpaceAfterCertainKeywords", [SyntaxKind.VarKeyword, SyntaxKind.ThrowKeyword, SyntaxKind.NewKeyword, SyntaxKind.DeleteKeyword, SyntaxKind.ReturnKeyword, SyntaxKind.TypeOfKeyword, SyntaxKind.AwaitKeyword], anyToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceAfterLetConstInVariableDeclaration", [SyntaxKind.LetKeyword, SyntaxKind.ConstKeyword], anyToken, [isNonJsxSameLineTokenContext, isStartOfVariableDeclarationList], RuleAction.Space),
+            rule("NoSpaceBeforeOpenParenInFuncCall", anyToken, SyntaxKind.OpenParenToken, [isNonJsxSameLineTokenContext, isFunctionCallOrNewContext, isPreviousTokenNotComma], RuleAction.Delete),
 
             // Special case for binary operators (that are keywords). For these we have to add a space and shouldn't follow any user options.
-            this.SpaceBeforeBinaryKeywordOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.BinaryKeywordOperators), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterBinaryKeywordOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.BinaryKeywordOperators, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
+            rule("SpaceBeforeBinaryKeywordOperator", anyToken, binaryKeywordOperators, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterBinaryKeywordOperator", binaryKeywordOperators, anyToken, [isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
 
-            // TypeScript-specific higher priority rules
-
-            this.SpaceAfterConstructor = new Rule(RuleDescriptor.create1(SyntaxKind.ConstructorKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterConstructor"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceAfterConstructor = new Rule(RuleDescriptor.create1(SyntaxKind.ConstructorKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterConstructor"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-
-            // Use of module as a function call. e.g.: import m2 = module("m2");
-            this.NoSpaceAfterModuleImport = new Rule(RuleDescriptor.create2(Shared.TokenRange.FromTokens([SyntaxKind.ModuleKeyword, SyntaxKind.RequireKeyword]), SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-
-            // Add a space around certain TypeScript keywords
-            this.SpaceAfterCertainTypeScriptKeywords = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.AbstractKeyword, SyntaxKind.ClassKeyword, SyntaxKind.DeclareKeyword, SyntaxKind.DefaultKeyword, SyntaxKind.EnumKeyword, SyntaxKind.ExportKeyword, SyntaxKind.ExtendsKeyword, SyntaxKind.GetKeyword, SyntaxKind.ImplementsKeyword, SyntaxKind.ImportKeyword, SyntaxKind.InterfaceKeyword, SyntaxKind.ModuleKeyword, SyntaxKind.NamespaceKeyword, SyntaxKind.PrivateKeyword, SyntaxKind.PublicKeyword, SyntaxKind.ProtectedKeyword, SyntaxKind.ReadonlyKeyword, SyntaxKind.SetKeyword, SyntaxKind.StaticKeyword, SyntaxKind.TypeKeyword, SyntaxKind.FromKeyword, SyntaxKind.KeyOfKeyword]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBeforeCertainTypeScriptKeywords = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.FromTokens([SyntaxKind.ExtendsKeyword, SyntaxKind.ImplementsKeyword, SyntaxKind.FromKeyword])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-
-            // Treat string literals in module names as identifiers, and add a space between the literal and the opening Brace braces, e.g.: module "m2" {
-            this.SpaceAfterModuleName = new Rule(RuleDescriptor.create1(SyntaxKind.StringLiteral, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsModuleDeclContext), RuleAction.Space));
-
-            // Lambda expressions
-            this.SpaceBeforeArrow = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.EqualsGreaterThanToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceAfterArrow = new Rule(RuleDescriptor.create3(SyntaxKind.EqualsGreaterThanToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-
-            // Optional parameters and let args
-            this.NoSpaceAfterEllipsis = new Rule(RuleDescriptor.create1(SyntaxKind.DotDotDotToken, SyntaxKind.Identifier), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterOptionalParameters = new Rule(RuleDescriptor.create3(SyntaxKind.QuestionToken, Shared.TokenRange.FromTokens([SyntaxKind.CloseParenToken, SyntaxKind.CommaToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNotBinaryOpContext), RuleAction.Delete));
-
-            // generics and type assertions
-            this.NoSpaceBeforeOpenAngularBracket = new Rule(RuleDescriptor.create2(Shared.TokenRange.TypeNames, SyntaxKind.LessThanToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeArgumentOrParameterOrAssertionContext), RuleAction.Delete));
-            this.NoSpaceBetweenCloseParenAndAngularBracket = new Rule(RuleDescriptor.create1(SyntaxKind.CloseParenToken, SyntaxKind.LessThanToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeArgumentOrParameterOrAssertionContext), RuleAction.Delete));
-            this.NoSpaceAfterOpenAngularBracket = new Rule(RuleDescriptor.create3(SyntaxKind.LessThanToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeArgumentOrParameterOrAssertionContext), RuleAction.Delete));
-            this.NoSpaceBeforeCloseAngularBracket = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.GreaterThanToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeArgumentOrParameterOrAssertionContext), RuleAction.Delete));
-            this.NoSpaceAfterCloseAngularBracket = new Rule(RuleDescriptor.create3(SyntaxKind.GreaterThanToken, Shared.TokenRange.FromTokens([SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken, SyntaxKind.GreaterThanToken, SyntaxKind.CommaToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeArgumentOrParameterOrAssertionContext), RuleAction.Delete));
-
-            // Remove spaces in empty interface literals. e.g.: x: {}
-            this.NoSpaceBetweenEmptyInterfaceBraceBrackets = new Rule(RuleDescriptor.create1(SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsObjectTypeContext), RuleAction.Delete));
-
-            // decorators
-            this.SpaceBeforeAt = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.AtToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceAfterAt = new Rule(RuleDescriptor.create3(SyntaxKind.AtToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.SpaceAfterDecorator = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.FromTokens([SyntaxKind.AbstractKeyword, SyntaxKind.Identifier, SyntaxKind.ExportKeyword, SyntaxKind.DefaultKeyword, SyntaxKind.ClassKeyword, SyntaxKind.StaticKeyword, SyntaxKind.PublicKeyword, SyntaxKind.PrivateKeyword, SyntaxKind.ProtectedKeyword, SyntaxKind.GetKeyword, SyntaxKind.SetKeyword, SyntaxKind.OpenBracketToken, SyntaxKind.AsteriskToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsEndOfDecoratorContextOnSameLine), RuleAction.Space));
-
-            this.NoSpaceBetweenFunctionKeywordAndStar = new Rule(RuleDescriptor.create1(SyntaxKind.FunctionKeyword, SyntaxKind.AsteriskToken), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclarationOrFunctionExpressionContext), RuleAction.Delete));
-            this.SpaceAfterStarInGeneratorDeclaration = new Rule(RuleDescriptor.create3(SyntaxKind.AsteriskToken, Shared.TokenRange.FromTokens([SyntaxKind.Identifier, SyntaxKind.OpenParenToken])), RuleOperation.create2(new RuleOperationContext(Rules.IsFunctionDeclarationOrFunctionExpressionContext), RuleAction.Space));
-            this.NoSpaceBetweenYieldKeywordAndStar = new Rule(RuleDescriptor.create1(SyntaxKind.YieldKeyword, SyntaxKind.AsteriskToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsYieldOrYieldStarWithOperand), RuleAction.Delete));
-            this.SpaceBetweenYieldOrYieldStarAndOperand = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.YieldKeyword, SyntaxKind.AsteriskToken]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsYieldOrYieldStarWithOperand), RuleAction.Space));
+            rule("SpaceAfterVoidOperator", SyntaxKind.VoidKeyword, anyToken, [isNonJsxSameLineTokenContext, isVoidOpContext], RuleAction.Space),
 
             // Async-await
-            this.SpaceBetweenAsyncAndOpenParen = new Rule(RuleDescriptor.create1(SyntaxKind.AsyncKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsArrowFunctionContext, Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBetweenAsyncAndFunctionKeyword = new Rule(RuleDescriptor.create1(SyntaxKind.AsyncKeyword, SyntaxKind.FunctionKeyword), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
+            rule("SpaceBetweenAsyncAndOpenParen", SyntaxKind.AsyncKeyword, SyntaxKind.OpenParenToken, [isArrowFunctionContext, isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBetweenAsyncAndFunctionKeyword", SyntaxKind.AsyncKeyword, SyntaxKind.FunctionKeyword, [isNonJsxSameLineTokenContext], RuleAction.Space),
 
             // template string
-            this.NoSpaceBetweenTagAndTemplateString = new Rule(RuleDescriptor.create3(SyntaxKind.Identifier, Shared.TokenRange.FromTokens([SyntaxKind.NoSubstitutionTemplateLiteral, SyntaxKind.TemplateHead])), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("NoSpaceBetweenTagAndTemplateString", SyntaxKind.Identifier, [SyntaxKind.NoSubstitutionTemplateLiteral, SyntaxKind.TemplateHead], [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
-            // jsx opening element
-            this.SpaceBeforeJsxAttribute = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.Identifier), RuleOperation.create2(new RuleOperationContext(Rules.IsNextTokenParentJsxAttribute, Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBeforeSlashInJsxOpeningElement = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.SlashToken), RuleOperation.create2(new RuleOperationContext(Rules.IsJsxSelfClosingElementContext, Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceBeforeGreaterThanTokenInJsxOpeningElement = new Rule(RuleDescriptor.create1(SyntaxKind.SlashToken, SyntaxKind.GreaterThanToken), RuleOperation.create2(new RuleOperationContext(Rules.IsJsxSelfClosingElementContext, Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeEqualInJsxAttribute = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.EqualsToken), RuleOperation.create2(new RuleOperationContext(Rules.IsJsxAttributeContext, Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterEqualInJsxAttribute = new Rule(RuleDescriptor.create3(SyntaxKind.EqualsToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsJsxAttributeContext, Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            // JSX opening elements
+            rule("SpaceBeforeJsxAttribute", anyToken, SyntaxKind.Identifier, [isNextTokenParentJsxAttribute, isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBeforeSlashInJsxOpeningElement", anyToken, SyntaxKind.SlashToken, [isJsxSelfClosingElementContext, isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceBeforeGreaterThanTokenInJsxOpeningElement", SyntaxKind.SlashToken, SyntaxKind.GreaterThanToken, [isJsxSelfClosingElementContext, isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeEqualInJsxAttribute", anyToken, SyntaxKind.EqualsToken, [isJsxAttributeContext, isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterEqualInJsxAttribute", SyntaxKind.EqualsToken, anyToken, [isJsxAttributeContext, isNonJsxSameLineTokenContext], RuleAction.Delete),
 
-            // No space before non-null assertion operator
-            this.NoSpaceBeforeNonNullAssertionOperator = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.ExclamationToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext, Rules.IsNonNullAssertionContext), RuleAction.Delete));
+            // TypeScript-specific rules
+            // Use of module as a function call. e.g.: import m2 = module("m2");
+            rule("NoSpaceAfterModuleImport", [SyntaxKind.ModuleKeyword, SyntaxKind.RequireKeyword], SyntaxKind.OpenParenToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            // Add a space around certain TypeScript keywords
+            rule(
+                "SpaceAfterCertainTypeScriptKeywords",
+                [
+                    SyntaxKind.AbstractKeyword,
+                    SyntaxKind.ClassKeyword,
+                    SyntaxKind.DeclareKeyword,
+                    SyntaxKind.DefaultKeyword,
+                    SyntaxKind.EnumKeyword,
+                    SyntaxKind.ExportKeyword,
+                    SyntaxKind.ExtendsKeyword,
+                    SyntaxKind.GetKeyword,
+                    SyntaxKind.ImplementsKeyword,
+                    SyntaxKind.ImportKeyword,
+                    SyntaxKind.InterfaceKeyword,
+                    SyntaxKind.ModuleKeyword,
+                    SyntaxKind.NamespaceKeyword,
+                    SyntaxKind.PrivateKeyword,
+                    SyntaxKind.PublicKeyword,
+                    SyntaxKind.ProtectedKeyword,
+                    SyntaxKind.ReadonlyKeyword,
+                    SyntaxKind.SetKeyword,
+                    SyntaxKind.StaticKeyword,
+                    SyntaxKind.TypeKeyword,
+                    SyntaxKind.FromKeyword,
+                    SyntaxKind.KeyOfKeyword,
+                ],
+                anyToken,
+                [isNonJsxSameLineTokenContext],
+                RuleAction.Space),
+            rule(
+                "SpaceBeforeCertainTypeScriptKeywords",
+                anyToken,
+                [SyntaxKind.ExtendsKeyword, SyntaxKind.ImplementsKeyword, SyntaxKind.FromKeyword],
+                [isNonJsxSameLineTokenContext],
+                RuleAction.Space),
+            // Treat string literals in module names as identifiers, and add a space between the literal and the opening Brace braces, e.g.: module "m2" {
+            rule("SpaceAfterModuleName", SyntaxKind.StringLiteral, SyntaxKind.OpenBraceToken, [isModuleDeclContext], RuleAction.Space),
 
-            ///
-            /// Rules controlled by user options
-            ///
+            // Lambda expressions
+            rule("SpaceBeforeArrow", anyToken, SyntaxKind.EqualsGreaterThanToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceAfterArrow", SyntaxKind.EqualsGreaterThanToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
 
-            // Insert space after comma delimiter
-            this.SpaceAfterComma = new Rule(RuleDescriptor.create3(SyntaxKind.CommaToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterCommaDelimiter"), Rules.IsNonJsxSameLineTokenContext, Rules.IsNonJsxElementContext, Rules.IsNextTokenNotCloseBracket), RuleAction.Space));
-            this.NoSpaceAfterComma = new Rule(RuleDescriptor.create3(SyntaxKind.CommaToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterCommaDelimiter"), Rules.IsNonJsxSameLineTokenContext, Rules.IsNonJsxElementContext), RuleAction.Delete));
+            // Optional parameters and let args
+            rule("NoSpaceAfterEllipsis", SyntaxKind.DotDotDotToken, SyntaxKind.Identifier, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterOptionalParameters", SyntaxKind.QuestionToken, [SyntaxKind.CloseParenToken, SyntaxKind.CommaToken], [isNonJsxSameLineTokenContext, isNotBinaryOpContext], RuleAction.Delete),
 
-            // Insert space before and after binary operators
-            this.SpaceBeforeBinaryOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.BinaryOperators), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceBeforeAndAfterBinaryOperators"), Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.SpaceAfterBinaryOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.BinaryOperators, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceBeforeAndAfterBinaryOperators"), Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Space));
-            this.NoSpaceBeforeBinaryOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.BinaryOperators), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceBeforeAndAfterBinaryOperators"), Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Delete));
-            this.NoSpaceAfterBinaryOperator = new Rule(RuleDescriptor.create4(Shared.TokenRange.BinaryOperators, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceBeforeAndAfterBinaryOperators"), Rules.IsNonJsxSameLineTokenContext, Rules.IsBinaryOpContext), RuleAction.Delete));
+            // Remove spaces in empty interface literals. e.g.: x: {}
+            rule("NoSpaceBetweenEmptyInterfaceBraceBrackets", SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken, [isNonJsxSameLineTokenContext, isObjectTypeContext], RuleAction.Delete),
+
+            // generics and type assertions
+            rule("NoSpaceBeforeOpenAngularBracket", typeNames, SyntaxKind.LessThanToken, [isNonJsxSameLineTokenContext, isTypeArgumentOrParameterOrAssertionContext], RuleAction.Delete),
+            rule("NoSpaceBetweenCloseParenAndAngularBracket", SyntaxKind.CloseParenToken, SyntaxKind.LessThanToken, [isNonJsxSameLineTokenContext, isTypeArgumentOrParameterOrAssertionContext], RuleAction.Delete),
+            rule("NoSpaceAfterOpenAngularBracket", SyntaxKind.LessThanToken, anyToken, [isNonJsxSameLineTokenContext, isTypeArgumentOrParameterOrAssertionContext], RuleAction.Delete),
+            rule("NoSpaceBeforeCloseAngularBracket", anyToken, SyntaxKind.GreaterThanToken, [isNonJsxSameLineTokenContext, isTypeArgumentOrParameterOrAssertionContext], RuleAction.Delete),
+            rule("NoSpaceAfterCloseAngularBracket",
+                SyntaxKind.GreaterThanToken,
+                [SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken, SyntaxKind.GreaterThanToken, SyntaxKind.CommaToken],
+                [isNonJsxSameLineTokenContext, isTypeArgumentOrParameterOrAssertionContext],
+                RuleAction.Delete),
+
+            // decorators
+            rule("SpaceBeforeAt", anyToken, SyntaxKind.AtToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceAfterAt", SyntaxKind.AtToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            // Insert space after @ in decorator
+            rule("SpaceAfterDecorator",
+                anyToken,
+                [
+                    SyntaxKind.AbstractKeyword,
+                    SyntaxKind.Identifier,
+                    SyntaxKind.ExportKeyword,
+                    SyntaxKind.DefaultKeyword,
+                    SyntaxKind.ClassKeyword,
+                    SyntaxKind.StaticKeyword,
+                    SyntaxKind.PublicKeyword,
+                    SyntaxKind.PrivateKeyword,
+                    SyntaxKind.ProtectedKeyword,
+                    SyntaxKind.GetKeyword,
+                    SyntaxKind.SetKeyword,
+                    SyntaxKind.OpenBracketToken,
+                    SyntaxKind.AsteriskToken,
+                ],
+                [isEndOfDecoratorContextOnSameLine],
+                RuleAction.Space),
+
+            rule("NoSpaceBeforeNonNullAssertionOperator", anyToken, SyntaxKind.ExclamationToken, [isNonJsxSameLineTokenContext, isNonNullAssertionContext], RuleAction.Delete),
+            rule("NoSpaceAfterNewKeywordOnConstructorSignature", SyntaxKind.NewKeyword, SyntaxKind.OpenParenToken, [isNonJsxSameLineTokenContext, isConstructorSignatureContext], RuleAction.Delete),
+        ];
+
+        // These rules are applied after high priority
+        const userConfigurableRules = [
+            // Treat constructor as an identifier in a function declaration, and remove spaces between constructor and following left parentheses
+            rule("SpaceAfterConstructor", SyntaxKind.ConstructorKeyword, SyntaxKind.OpenParenToken, [isOptionEnabled("insertSpaceAfterConstructor"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceAfterConstructor", SyntaxKind.ConstructorKeyword, SyntaxKind.OpenParenToken, [isOptionDisabledOrUndefined("insertSpaceAfterConstructor"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+
+            rule("SpaceAfterComma", SyntaxKind.CommaToken, anyToken, [isOptionEnabled("insertSpaceAfterCommaDelimiter"), isNonJsxSameLineTokenContext, isNonJsxElementContext, isNextTokenNotCloseBracket], RuleAction.Space),
+            rule("NoSpaceAfterComma", SyntaxKind.CommaToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterCommaDelimiter"), isNonJsxSameLineTokenContext, isNonJsxElementContext], RuleAction.Delete),
+
+            // Insert space after function keyword for anonymous functions
+            rule("SpaceAfterAnonymousFunctionKeyword", SyntaxKind.FunctionKeyword, SyntaxKind.OpenParenToken, [isOptionEnabled("insertSpaceAfterFunctionKeywordForAnonymousFunctions"), isFunctionDeclContext], RuleAction.Space),
+            rule("NoSpaceAfterAnonymousFunctionKeyword", SyntaxKind.FunctionKeyword, SyntaxKind.OpenParenToken, [isOptionDisabledOrUndefined("insertSpaceAfterFunctionKeywordForAnonymousFunctions"), isFunctionDeclContext], RuleAction.Delete),
 
             // Insert space after keywords in control flow statements
-            this.SpaceAfterKeywordInControl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Keywords, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterKeywordsInControlFlowStatements"), Rules.IsControlDeclContext), RuleAction.Space));
-            this.NoSpaceAfterKeywordInControl = new Rule(RuleDescriptor.create2(Shared.TokenRange.Keywords, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterKeywordsInControlFlowStatements"), Rules.IsControlDeclContext), RuleAction.Delete));
+            rule("SpaceAfterKeywordInControl", keywords, SyntaxKind.OpenParenToken, [isOptionEnabled("insertSpaceAfterKeywordsInControlFlowStatements"), isControlDeclContext], RuleAction.Space),
+            rule("NoSpaceAfterKeywordInControl", keywords, SyntaxKind.OpenParenToken, [isOptionDisabledOrUndefined("insertSpaceAfterKeywordsInControlFlowStatements"), isControlDeclContext], RuleAction.Delete),
+
+            // Insert space after opening and before closing nonempty parenthesis
+            rule("SpaceAfterOpenParen", SyntaxKind.OpenParenToken, anyToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBeforeCloseParen", anyToken, SyntaxKind.CloseParenToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBetweenOpenParens", SyntaxKind.OpenParenToken, SyntaxKind.OpenParenToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceBetweenParens", SyntaxKind.OpenParenToken, SyntaxKind.CloseParenToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterOpenParen", SyntaxKind.OpenParenToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeCloseParen", anyToken, SyntaxKind.CloseParenToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+
+            // Insert space after opening and before closing nonempty brackets
+            rule("SpaceAfterOpenBracket", SyntaxKind.OpenBracketToken, anyToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBeforeCloseBracket", anyToken, SyntaxKind.CloseBracketToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceBetweenBrackets", SyntaxKind.OpenBracketToken, SyntaxKind.CloseBracketToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterOpenBracket", SyntaxKind.OpenBracketToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeCloseBracket", anyToken, SyntaxKind.CloseBracketToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+
+            // Insert a space after { and before } in single-line contexts, but remove space from empty object literals {}.
+            rule("SpaceAfterOpenBrace", SyntaxKind.OpenBraceToken, anyToken, [isOptionEnabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), isBraceWrappedContext], RuleAction.Space),
+            rule("SpaceBeforeCloseBrace", anyToken, SyntaxKind.CloseBraceToken, [isOptionEnabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), isBraceWrappedContext], RuleAction.Space),
+            rule("NoSpaceBetweenEmptyBraceBrackets", SyntaxKind.OpenBraceToken, SyntaxKind.CloseBraceToken, [isNonJsxSameLineTokenContext, isObjectContext], RuleAction.Delete),
+            rule("NoSpaceAfterOpenBrace", SyntaxKind.OpenBraceToken, anyToken, [isOptionDisabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeCloseBrace", anyToken, SyntaxKind.CloseBraceToken, [isOptionDisabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+
+            // Insert space after opening and before closing template string braces
+            rule("SpaceAfterTemplateHeadAndMiddle", [SyntaxKind.TemplateHead, SyntaxKind.TemplateMiddle], anyToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("SpaceBeforeTemplateMiddleAndTail", anyToken, [SyntaxKind.TemplateMiddle, SyntaxKind.TemplateTail], [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), isNonJsxSameLineTokenContext], RuleAction.Space),
+            rule("NoSpaceAfterTemplateHeadAndMiddle", [SyntaxKind.TemplateHead, SyntaxKind.TemplateMiddle], anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceBeforeTemplateMiddleAndTail", anyToken, [SyntaxKind.TemplateMiddle, SyntaxKind.TemplateTail], [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), isNonJsxSameLineTokenContext], RuleAction.Delete),
+
+            // No space after { and before } in JSX expression
+            rule("SpaceAfterOpenBraceInJsxExpression", SyntaxKind.OpenBraceToken, anyToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), isNonJsxSameLineTokenContext, isJsxExpressionContext], RuleAction.Space),
+            rule("SpaceBeforeCloseBraceInJsxExpression", anyToken, SyntaxKind.CloseBraceToken, [isOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), isNonJsxSameLineTokenContext, isJsxExpressionContext], RuleAction.Space),
+            rule("NoSpaceAfterOpenBraceInJsxExpression", SyntaxKind.OpenBraceToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), isNonJsxSameLineTokenContext, isJsxExpressionContext], RuleAction.Delete),
+            rule("NoSpaceBeforeCloseBraceInJsxExpression", anyToken, SyntaxKind.CloseBraceToken, [isOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), isNonJsxSameLineTokenContext, isJsxExpressionContext], RuleAction.Delete),
+
+            // Insert space after semicolon in for statement
+            rule("SpaceAfterSemicolonInFor", SyntaxKind.SemicolonToken, anyToken, [isOptionEnabled("insertSpaceAfterSemicolonInForStatements"), isNonJsxSameLineTokenContext, isForContext], RuleAction.Space),
+            rule("NoSpaceAfterSemicolonInFor", SyntaxKind.SemicolonToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterSemicolonInForStatements"), isNonJsxSameLineTokenContext, isForContext], RuleAction.Delete),
+
+            // Insert space before and after binary operators
+            rule("SpaceBeforeBinaryOperator", anyToken, binaryOperators, [isOptionEnabled("insertSpaceBeforeAndAfterBinaryOperators"), isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("SpaceAfterBinaryOperator", binaryOperators, anyToken, [isOptionEnabled("insertSpaceBeforeAndAfterBinaryOperators"), isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Space),
+            rule("NoSpaceBeforeBinaryOperator", anyToken, binaryOperators, [isOptionDisabledOrUndefined("insertSpaceBeforeAndAfterBinaryOperators"), isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Delete),
+            rule("NoSpaceAfterBinaryOperator", binaryOperators, anyToken, [isOptionDisabledOrUndefined("insertSpaceBeforeAndAfterBinaryOperators"), isNonJsxSameLineTokenContext, isBinaryOpContext], RuleAction.Delete),
+
+            rule("SpaceBeforeOpenParenInFuncDecl", anyToken, SyntaxKind.OpenParenToken, [isOptionEnabled("insertSpaceBeforeFunctionParenthesis"), isNonJsxSameLineTokenContext, isFunctionDeclContext], RuleAction.Space),
+            rule("NoSpaceBeforeOpenParenInFuncDecl", anyToken, SyntaxKind.OpenParenToken, [isOptionDisabledOrUndefined("insertSpaceBeforeFunctionParenthesis"), isNonJsxSameLineTokenContext, isFunctionDeclContext], RuleAction.Delete),
+
+            // Open Brace braces after control block
+            rule("NewLineBeforeOpenBraceInControl", controlOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionEnabled("placeOpenBraceOnNewLineForControlBlocks"), isControlDeclContext, isBeforeMultilineBlockContext], RuleAction.NewLine, RuleFlags.CanDeleteNewLines),
 
             // Open Brace braces after function
             // TypeScript: Function can have return types, which can be made of tons of different token kinds
-            this.NewLineBeforeOpenBraceInFunction = new Rule(RuleDescriptor.create2(this.FunctionOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("placeOpenBraceOnNewLineForFunctions"), Rules.IsFunctionDeclContext, Rules.IsBeforeMultilineBlockContext), RuleAction.NewLine), RuleFlags.CanDeleteNewLines);
-
+            rule("NewLineBeforeOpenBraceInFunction", functionOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionEnabled("placeOpenBraceOnNewLineForFunctions"), isFunctionDeclContext, isBeforeMultilineBlockContext], RuleAction.NewLine, RuleFlags.CanDeleteNewLines),
             // Open Brace braces after TypeScript module/class/interface
-            this.NewLineBeforeOpenBraceInTypeScriptDeclWithBlock = new Rule(RuleDescriptor.create2(this.TypeScriptOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("placeOpenBraceOnNewLineForFunctions"), Rules.IsTypeScriptDeclWithBlockContext, Rules.IsBeforeMultilineBlockContext), RuleAction.NewLine), RuleFlags.CanDeleteNewLines);
+            rule("NewLineBeforeOpenBraceInTypeScriptDeclWithBlock", typeScriptOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionEnabled("placeOpenBraceOnNewLineForFunctions"), isTypeScriptDeclWithBlockContext, isBeforeMultilineBlockContext], RuleAction.NewLine, RuleFlags.CanDeleteNewLines),
 
-            // Open Brace braces after control block
-            this.NewLineBeforeOpenBraceInControl = new Rule(RuleDescriptor.create2(this.ControlOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("placeOpenBraceOnNewLineForControlBlocks"), Rules.IsControlDeclContext, Rules.IsBeforeMultilineBlockContext), RuleAction.NewLine), RuleFlags.CanDeleteNewLines);
+            rule("SpaceAfterTypeAssertion", SyntaxKind.GreaterThanToken, anyToken, [isOptionEnabled("insertSpaceAfterTypeAssertion"), isNonJsxSameLineTokenContext, isTypeAssertionContext], RuleAction.Space),
+            rule("NoSpaceAfterTypeAssertion", SyntaxKind.GreaterThanToken, anyToken, [isOptionDisabledOrUndefined("insertSpaceAfterTypeAssertion"), isNonJsxSameLineTokenContext, isTypeAssertionContext], RuleAction.Delete),
+        ];
 
-            // Insert space after semicolon in for statement
-            this.SpaceAfterSemicolonInFor = new Rule(RuleDescriptor.create3(SyntaxKind.SemicolonToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterSemicolonInForStatements"), Rules.IsNonJsxSameLineTokenContext, Rules.IsForContext), RuleAction.Space));
-            this.NoSpaceAfterSemicolonInFor = new Rule(RuleDescriptor.create3(SyntaxKind.SemicolonToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterSemicolonInForStatements"), Rules.IsNonJsxSameLineTokenContext, Rules.IsForContext), RuleAction.Delete));
+        // These rules are lower in priority than user-configurable
+        const lowPriorityCommonRules = [
+            // Space after keyword but not before ; or : or ?
+            rule("NoSpaceBeforeSemicolon", anyToken, SyntaxKind.SemicolonToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
-            // Insert space after opening and before closing nonempty parenthesis
-            this.SpaceAfterOpenParen = new Rule(RuleDescriptor.create3(SyntaxKind.OpenParenToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBeforeCloseParen = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBetweenOpenParens = new Rule(RuleDescriptor.create1(SyntaxKind.OpenParenToken, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceBetweenParens = new Rule(RuleDescriptor.create1(SyntaxKind.OpenParenToken, SyntaxKind.CloseParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterOpenParen = new Rule(RuleDescriptor.create3(SyntaxKind.OpenParenToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeCloseParen = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyParenthesis"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("SpaceBeforeOpenBraceInControl", controlOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForControlBlocks"), isControlDeclContext, isNotFormatOnEnter, isSameLineTokenOrBeforeBlockContext], RuleAction.Space, RuleFlags.CanDeleteNewLines),
+            rule("SpaceBeforeOpenBraceInFunction", functionOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForFunctions"), isFunctionDeclContext, isBeforeBlockContext, isNotFormatOnEnter, isSameLineTokenOrBeforeBlockContext], RuleAction.Space, RuleFlags.CanDeleteNewLines),
+            rule("SpaceBeforeOpenBraceInTypeScriptDeclWithBlock", typeScriptOpenBraceLeftTokenRange, SyntaxKind.OpenBraceToken, [isOptionDisabledOrUndefinedOrTokensOnSameLine("placeOpenBraceOnNewLineForFunctions"), isTypeScriptDeclWithBlockContext, isNotFormatOnEnter, isSameLineTokenOrBeforeBlockContext], RuleAction.Space, RuleFlags.CanDeleteNewLines),
 
-            // Insert space after opening and before closing nonempty brackets
-            this.SpaceAfterOpenBracket = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBracketToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.SpaceBeforeCloseBracket = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBracketToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceBetweenBrackets = new Rule(RuleDescriptor.create1(SyntaxKind.OpenBracketToken, SyntaxKind.CloseBracketToken), RuleOperation.create2(new RuleOperationContext(Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceAfterOpenBracket = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBracketToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.NoSpaceBeforeCloseBracket = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBracketToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingNonemptyBrackets"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
+            rule("NoSpaceBeforeComma", anyToken, SyntaxKind.CommaToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            // No space before and after indexer
+            rule("NoSpaceBeforeOpenBracket", anyTokenExcept(SyntaxKind.AsyncKeyword), SyntaxKind.OpenBracketToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterCloseBracket", SyntaxKind.CloseBracketToken, anyToken, [isNonJsxSameLineTokenContext, isNotBeforeBlockInFunctionDeclarationContext], RuleAction.Delete),
+            rule("SpaceAfterSemicolon", SyntaxKind.SemicolonToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
 
-            // Insert space after opening and before closing template string braces
-            this.NoSpaceAfterTemplateHeadAndMiddle = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.TemplateHead, SyntaxKind.TemplateMiddle]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.SpaceAfterTemplateHeadAndMiddle = new Rule(RuleDescriptor.create4(Shared.TokenRange.FromTokens([SyntaxKind.TemplateHead, SyntaxKind.TemplateMiddle]), Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
-            this.NoSpaceBeforeTemplateMiddleAndTail = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.FromTokens([SyntaxKind.TemplateMiddle, SyntaxKind.TemplateTail])), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Delete));
-            this.SpaceBeforeTemplateMiddleAndTail = new Rule(RuleDescriptor.create4(Shared.TokenRange.Any, Shared.TokenRange.FromTokens([SyntaxKind.TemplateMiddle, SyntaxKind.TemplateTail])), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingTemplateStringBraces"), Rules.IsNonJsxSameLineTokenContext), RuleAction.Space));
+            // Add a space between statements. All keywords except (do,else,case) has open/close parens after them.
+            // So, we have a rule to add a space for [),Any], [do,Any], [else,Any], and [case,Any]
+            rule(
+                "SpaceBetweenStatements",
+                [SyntaxKind.CloseParenToken, SyntaxKind.DoKeyword, SyntaxKind.ElseKeyword, SyntaxKind.CaseKeyword],
+                anyToken,
+                [isNonJsxSameLineTokenContext, isNonJsxElementContext, isNotForContext],
+                RuleAction.Space),
+            // This low-pri rule takes care of "try {" and "finally {" in case the rule SpaceBeforeOpenBraceInControl didn't execute on FormatOnEnter.
+            rule("SpaceAfterTryFinally", [SyntaxKind.TryKeyword, SyntaxKind.FinallyKeyword], SyntaxKind.OpenBraceToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
+        ];
 
-            // No space after { and before } in JSX expression
-            this.NoSpaceAfterOpenBraceInJsxExpression = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBraceToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), Rules.IsNonJsxSameLineTokenContext, Rules.IsJsxExpressionContext), RuleAction.Delete));
-            this.SpaceAfterOpenBraceInJsxExpression = new Rule(RuleDescriptor.create3(SyntaxKind.OpenBraceToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), Rules.IsNonJsxSameLineTokenContext, Rules.IsJsxExpressionContext), RuleAction.Space));
-            this.NoSpaceBeforeCloseBraceInJsxExpression = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), Rules.IsNonJsxSameLineTokenContext, Rules.IsJsxExpressionContext), RuleAction.Delete));
-            this.SpaceBeforeCloseBraceInJsxExpression = new Rule(RuleDescriptor.create2(Shared.TokenRange.Any, SyntaxKind.CloseBraceToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterOpeningAndBeforeClosingJsxExpressionBraces"), Rules.IsNonJsxSameLineTokenContext, Rules.IsJsxExpressionContext), RuleAction.Space));
+        return [
+            ...highPriorityCommonRules,
+            ...userConfigurableRules,
+            ...lowPriorityCommonRules,
+        ];
+    }
 
-            // Insert space after function keyword for anonymous functions
-            this.SpaceAfterAnonymousFunctionKeyword = new Rule(RuleDescriptor.create1(SyntaxKind.FunctionKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterFunctionKeywordForAnonymousFunctions"), Rules.IsFunctionDeclContext), RuleAction.Space));
-            this.NoSpaceAfterAnonymousFunctionKeyword = new Rule(RuleDescriptor.create1(SyntaxKind.FunctionKeyword, SyntaxKind.OpenParenToken), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterFunctionKeywordForAnonymousFunctions"), Rules.IsFunctionDeclContext), RuleAction.Delete));
+    function rule(
+        debugName: string,
+        left: SyntaxKind | ReadonlyArray<SyntaxKind> | TokenRange,
+        right: SyntaxKind | ReadonlyArray<SyntaxKind> | TokenRange,
+        context: ReadonlyArray<ContextPredicate>,
+        action: RuleAction,
+        flags: RuleFlags = RuleFlags.None,
+    ): RuleSpec {
+        return { leftTokenRange: toTokenRange(left), rightTokenRange: toTokenRange(right), rule: { debugName, context, action, flags } };
+    }
 
-            // No space after type assertion
-            this.NoSpaceAfterTypeAssertion = new Rule(RuleDescriptor.create3(SyntaxKind.GreaterThanToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionDisabledOrUndefined("insertSpaceAfterTypeAssertion"), Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeAssertionContext), RuleAction.Delete));
-            this.SpaceAfterTypeAssertion = new Rule(RuleDescriptor.create3(SyntaxKind.GreaterThanToken, Shared.TokenRange.Any), RuleOperation.create2(new RuleOperationContext(Rules.IsOptionEnabled("insertSpaceAfterTypeAssertion"), Rules.IsNonJsxSameLineTokenContext, Rules.IsTypeAssertionContext), RuleAction.Space));
+    function tokenRangeFrom(tokens: ReadonlyArray<SyntaxKind>): TokenRange {
+        return { tokens, isSpecific: true };
+    }
 
-            // These rules are higher in priority than user-configurable rules.
-            this.HighPriorityCommonRules = [
-                this.IgnoreBeforeComment, this.IgnoreAfterLineComment,
-                this.NoSpaceBeforeColon, this.SpaceAfterColon, this.NoSpaceBeforeQuestionMark, this.SpaceAfterQuestionMarkInConditionalOperator,
-                this.NoSpaceAfterQuestionMark,
-                this.NoSpaceBeforeDot, this.NoSpaceAfterDot,
-                this.NoSpaceAfterUnaryPrefixOperator,
-                this.NoSpaceAfterUnaryPreincrementOperator, this.NoSpaceAfterUnaryPredecrementOperator,
-                this.NoSpaceBeforeUnaryPostincrementOperator, this.NoSpaceBeforeUnaryPostdecrementOperator,
-                this.SpaceAfterPostincrementWhenFollowedByAdd,
-                this.SpaceAfterAddWhenFollowedByUnaryPlus, this.SpaceAfterAddWhenFollowedByPreincrement,
-                this.SpaceAfterPostdecrementWhenFollowedBySubtract,
-                this.SpaceAfterSubtractWhenFollowedByUnaryMinus, this.SpaceAfterSubtractWhenFollowedByPredecrement,
-                this.NoSpaceAfterCloseBrace,
-                this.NewLineBeforeCloseBraceInBlockContext,
-                this.SpaceAfterCloseBrace, this.SpaceBetweenCloseBraceAndElse, this.SpaceBetweenCloseBraceAndWhile, this.NoSpaceBetweenEmptyBraceBrackets,
-                this.NoSpaceBetweenFunctionKeywordAndStar, this.SpaceAfterStarInGeneratorDeclaration,
-                this.SpaceAfterFunctionInFuncDecl, this.NewLineAfterOpenBraceInBlockContext, this.SpaceAfterGetSetInMember,
-                this.NoSpaceBetweenYieldKeywordAndStar, this.SpaceBetweenYieldOrYieldStarAndOperand,
-                this.NoSpaceBetweenReturnAndSemicolon,
-                this.SpaceAfterCertainKeywords,
-                this.SpaceAfterLetConstInVariableDeclaration,
-                this.NoSpaceBeforeOpenParenInFuncCall,
-                this.SpaceBeforeBinaryKeywordOperator, this.SpaceAfterBinaryKeywordOperator,
-                this.SpaceAfterVoidOperator,
-                this.SpaceBetweenAsyncAndOpenParen, this.SpaceBetweenAsyncAndFunctionKeyword,
-                this.NoSpaceBetweenTagAndTemplateString,
-                this.SpaceBeforeJsxAttribute, this.SpaceBeforeSlashInJsxOpeningElement, this.NoSpaceBeforeGreaterThanTokenInJsxOpeningElement,
-                this.NoSpaceBeforeEqualInJsxAttribute, this.NoSpaceAfterEqualInJsxAttribute,
+    function toTokenRange(arg: SyntaxKind | ReadonlyArray<SyntaxKind> | TokenRange): TokenRange {
+        return typeof arg === "number" ? tokenRangeFrom([arg]) : isArray(arg) ? tokenRangeFrom(arg) : arg;
+    }
 
-                // TypeScript-specific rules
-                this.NoSpaceAfterModuleImport,
-                this.SpaceAfterCertainTypeScriptKeywords, this.SpaceBeforeCertainTypeScriptKeywords,
-                this.SpaceAfterModuleName,
-                this.SpaceBeforeArrow, this.SpaceAfterArrow,
-                this.NoSpaceAfterEllipsis,
-                this.NoSpaceAfterOptionalParameters,
-                this.NoSpaceBetweenEmptyInterfaceBraceBrackets,
-                this.NoSpaceBeforeOpenAngularBracket,
-                this.NoSpaceBetweenCloseParenAndAngularBracket,
-                this.NoSpaceAfterOpenAngularBracket,
-                this.NoSpaceBeforeCloseAngularBracket,
-                this.NoSpaceAfterCloseAngularBracket,
-                this.SpaceBeforeAt,
-                this.NoSpaceAfterAt,
-                this.SpaceAfterDecorator,
-                this.NoSpaceBeforeNonNullAssertionOperator,
-                this.NoSpaceAfterNewKeywordOnConstructorSignature
-            ];
-
-            // These rules are applied after high priority rules.
-            this.UserConfigurableRules = [
-                this.SpaceAfterConstructor, this.NoSpaceAfterConstructor,
-                this.SpaceAfterComma, this.NoSpaceAfterComma,
-                this.SpaceAfterAnonymousFunctionKeyword, this.NoSpaceAfterAnonymousFunctionKeyword,
-                this.SpaceAfterKeywordInControl, this.NoSpaceAfterKeywordInControl,
-                this.SpaceAfterOpenParen, this.SpaceBeforeCloseParen, this.SpaceBetweenOpenParens, this.NoSpaceBetweenParens, this.NoSpaceAfterOpenParen, this.NoSpaceBeforeCloseParen,
-                this.SpaceAfterOpenBracket, this.SpaceBeforeCloseBracket, this.NoSpaceBetweenBrackets, this.NoSpaceAfterOpenBracket, this.NoSpaceBeforeCloseBracket,
-                this.SpaceAfterOpenBrace, this.SpaceBeforeCloseBrace, this.NoSpaceBetweenEmptyBraceBrackets, this.NoSpaceAfterOpenBrace, this.NoSpaceBeforeCloseBrace,
-                this.SpaceAfterTemplateHeadAndMiddle, this.SpaceBeforeTemplateMiddleAndTail, this.NoSpaceAfterTemplateHeadAndMiddle, this.NoSpaceBeforeTemplateMiddleAndTail,
-                this.SpaceAfterOpenBraceInJsxExpression, this.SpaceBeforeCloseBraceInJsxExpression, this.NoSpaceAfterOpenBraceInJsxExpression, this.NoSpaceBeforeCloseBraceInJsxExpression,
-                this.SpaceAfterSemicolonInFor, this.NoSpaceAfterSemicolonInFor,
-                this.SpaceBeforeBinaryOperator, this.SpaceAfterBinaryOperator, this.NoSpaceBeforeBinaryOperator, this.NoSpaceAfterBinaryOperator,
-                this.SpaceBeforeOpenParenInFuncDecl, this.NoSpaceBeforeOpenParenInFuncDecl,
-                this.NewLineBeforeOpenBraceInControl,
-                this.NewLineBeforeOpenBraceInFunction, this.NewLineBeforeOpenBraceInTypeScriptDeclWithBlock,
-                this.SpaceAfterTypeAssertion, this.NoSpaceAfterTypeAssertion
-            ];
-
-            // These rules are lower in priority than user-configurable rules.
-            this.LowPriorityCommonRules = [
-                this.NoSpaceBeforeSemicolon,
-                this.SpaceBeforeOpenBraceInControl, this.SpaceBeforeOpenBraceInFunction, this.SpaceBeforeOpenBraceInTypeScriptDeclWithBlock,
-                this.NoSpaceBeforeComma,
-                this.NoSpaceBeforeOpenBracket,
-                this.NoSpaceAfterCloseBracket,
-                this.SpaceAfterSemicolon,
-                this.SpaceBetweenStatements, this.SpaceAfterTryFinally
-            ];
-
-            if (Debug.isDebugging) {
-                const o: ts.MapLike<any> = <any>this;
-                for (const name in o) {
-                    const rule = o[name];
-                    if (rule instanceof Rule) {
-                        rule.debugName = name;
-                    }
-                }
+    function tokenRangeFromRange(from: SyntaxKind, to: SyntaxKind, except: ReadonlyArray<SyntaxKind> = []): TokenRange {
+        const tokens: SyntaxKind[] = [];
+        for (let token = from; token <= to; token++) {
+            if (!contains(except, token)) {
+                tokens.push(token);
             }
         }
+        return tokenRangeFrom(tokens);
+    }
 
-        ///
-        /// Contexts
-        ///
+    ///
+    /// Contexts
+    ///
 
-        static IsOptionEnabled(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
-            return (context) => context.options && context.options.hasOwnProperty(optionName) && !!context.options[optionName];
-        }
+    function isOptionEnabled(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
+        return (context) => context.options && context.options.hasOwnProperty(optionName) && !!context.options[optionName];
+    }
 
-        static IsOptionDisabled(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
-            return (context) => context.options && context.options.hasOwnProperty(optionName) && !context.options[optionName];
-        }
+    function isOptionDisabled(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
+        return (context) => context.options && context.options.hasOwnProperty(optionName) && !context.options[optionName];
+    }
 
-        static IsOptionDisabledOrUndefined(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
-            return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !context.options[optionName];
-        }
+    function isOptionDisabledOrUndefined(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
+        return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !context.options[optionName];
+    }
 
-        static isOptionDisabledOrUndefinedOrTokensOnSameLine(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
-            return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !context.options[optionName] || context.TokensAreOnSameLine();
-        }
+    function isOptionDisabledOrUndefinedOrTokensOnSameLine(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
+        return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !context.options[optionName] || context.TokensAreOnSameLine();
+    }
 
-        static IsOptionEnabledOrUndefined(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
-            return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !!context.options[optionName];
-        }
+    function isOptionEnabledOrUndefined(optionName: keyof FormatCodeSettings): (context: FormattingContext) => boolean {
+        return (context) => !context.options || !context.options.hasOwnProperty(optionName) || !!context.options[optionName];
+    }
 
-        static IsForContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ForStatement;
-        }
+    function isForContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ForStatement;
+    }
 
-        static IsNotForContext(context: FormattingContext): boolean {
-            return !Rules.IsForContext(context);
-        }
+    function isNotForContext(context: FormattingContext): boolean {
+        return !isForContext(context);
+    }
 
-        static IsBinaryOpContext(context: FormattingContext): boolean {
+    function isBinaryOpContext(context: FormattingContext): boolean {
 
-            switch (context.contextNode.kind) {
-                case SyntaxKind.BinaryExpression:
-                case SyntaxKind.ConditionalExpression:
-                case SyntaxKind.AsExpression:
-                case SyntaxKind.ExportSpecifier:
-                case SyntaxKind.ImportSpecifier:
-                case SyntaxKind.TypePredicate:
-                case SyntaxKind.UnionType:
-                case SyntaxKind.IntersectionType:
-                    return true;
-
-                // equals in binding elements: function foo([[x, y] = [1, 2]])
-                case SyntaxKind.BindingElement:
-                // equals in type X = ...
-                case SyntaxKind.TypeAliasDeclaration:
-                // equal in import a = module('a');
-                case SyntaxKind.ImportEqualsDeclaration:
-                // equal in let a = 0;
-                case SyntaxKind.VariableDeclaration:
-                // equal in p = 0;
-                case SyntaxKind.Parameter:
-                case SyntaxKind.EnumMember:
-                case SyntaxKind.PropertyDeclaration:
-                case SyntaxKind.PropertySignature:
-                    return context.currentTokenSpan.kind === SyntaxKind.EqualsToken || context.nextTokenSpan.kind === SyntaxKind.EqualsToken;
-                // "in" keyword in for (let x in []) { }
-                case SyntaxKind.ForInStatement:
-                // "in" keyword in [P in keyof T]: T[P]
-                case SyntaxKind.TypeParameter:
-                    return context.currentTokenSpan.kind === SyntaxKind.InKeyword || context.nextTokenSpan.kind === SyntaxKind.InKeyword;
-                // Technically, "of" is not a binary operator, but format it the same way as "in"
-                case SyntaxKind.ForOfStatement:
-                    return context.currentTokenSpan.kind === SyntaxKind.OfKeyword || context.nextTokenSpan.kind === SyntaxKind.OfKeyword;
-            }
-            return false;
-        }
-
-        static IsNotBinaryOpContext(context: FormattingContext): boolean {
-            return !Rules.IsBinaryOpContext(context);
-        }
-
-        static IsConditionalOperatorContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ConditionalExpression;
-        }
-
-        static IsSameLineTokenOrBeforeBlockContext(context: FormattingContext): boolean {
-            return context.TokensAreOnSameLine() || Rules.IsBeforeBlockContext(context);
-        }
-
-        static IsBraceWrappedContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ObjectBindingPattern || Rules.IsSingleLineBlockContext(context);
-        }
-
-        // This check is done before an open brace in a control construct, a function, or a typescript block declaration
-        static IsBeforeMultilineBlockContext(context: FormattingContext): boolean {
-            return Rules.IsBeforeBlockContext(context) && !(context.NextNodeAllOnSameLine() || context.NextNodeBlockIsOnOneLine());
-        }
-
-        static IsMultilineBlockContext(context: FormattingContext): boolean {
-            return Rules.IsBlockContext(context) && !(context.ContextNodeAllOnSameLine() || context.ContextNodeBlockIsOnOneLine());
-        }
-
-        static IsSingleLineBlockContext(context: FormattingContext): boolean {
-            return Rules.IsBlockContext(context) && (context.ContextNodeAllOnSameLine() || context.ContextNodeBlockIsOnOneLine());
-        }
-
-        static IsBlockContext(context: FormattingContext): boolean {
-            return Rules.NodeIsBlockContext(context.contextNode);
-        }
-
-        static IsBeforeBlockContext(context: FormattingContext): boolean {
-            return Rules.NodeIsBlockContext(context.nextTokenParent);
-        }
-
-        // IMPORTANT!!! This method must return true ONLY for nodes with open and close braces as immediate children
-        static NodeIsBlockContext(node: Node): boolean {
-            if (Rules.NodeIsTypeScriptDeclWithBlockContext(node)) {
-                // This means we are in a context that looks like a block to the user, but in the grammar is actually not a node (it's a class, module, enum, object type literal, etc).
+        switch (context.contextNode.kind) {
+            case SyntaxKind.BinaryExpression:
+            case SyntaxKind.ConditionalExpression:
+            case SyntaxKind.AsExpression:
+            case SyntaxKind.ExportSpecifier:
+            case SyntaxKind.ImportSpecifier:
+            case SyntaxKind.TypePredicate:
+            case SyntaxKind.UnionType:
+            case SyntaxKind.IntersectionType:
                 return true;
-            }
 
-            switch (node.kind) {
-                case SyntaxKind.Block:
-                case SyntaxKind.CaseBlock:
-                case SyntaxKind.ObjectLiteralExpression:
-                case SyntaxKind.ModuleBlock:
+            // equals in binding elements: function foo([[x, y] = [1, 2]])
+            case SyntaxKind.BindingElement:
+            // equals in type X = ...
+            case SyntaxKind.TypeAliasDeclaration:
+            // equal in import a = module('a');
+            case SyntaxKind.ImportEqualsDeclaration:
+            // equal in let a = 0;
+            case SyntaxKind.VariableDeclaration:
+            // equal in p = 0;
+            case SyntaxKind.Parameter:
+            case SyntaxKind.EnumMember:
+            case SyntaxKind.PropertyDeclaration:
+            case SyntaxKind.PropertySignature:
+                return context.currentTokenSpan.kind === SyntaxKind.EqualsToken || context.nextTokenSpan.kind === SyntaxKind.EqualsToken;
+            // "in" keyword in for (let x in []) { }
+            case SyntaxKind.ForInStatement:
+            // "in" keyword in [P in keyof T]: T[P]
+            case SyntaxKind.TypeParameter:
+                return context.currentTokenSpan.kind === SyntaxKind.InKeyword || context.nextTokenSpan.kind === SyntaxKind.InKeyword;
+            // Technically, "of" is not a binary operator, but format it the same way as "in"
+            case SyntaxKind.ForOfStatement:
+                return context.currentTokenSpan.kind === SyntaxKind.OfKeyword || context.nextTokenSpan.kind === SyntaxKind.OfKeyword;
+        }
+        return false;
+    }
+
+    function isNotBinaryOpContext(context: FormattingContext): boolean {
+        return !isBinaryOpContext(context);
+    }
+
+    function isConditionalOperatorContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ConditionalExpression;
+    }
+
+    function isSameLineTokenOrBeforeBlockContext(context: FormattingContext): boolean {
+        return context.TokensAreOnSameLine() || isBeforeBlockContext(context);
+    }
+
+    function isBraceWrappedContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ObjectBindingPattern || isSingleLineBlockContext(context);
+    }
+
+    // This check is done before an open brace in a control construct, a function, or a typescript block declaration
+    function isBeforeMultilineBlockContext(context: FormattingContext): boolean {
+        return isBeforeBlockContext(context) && !(context.NextNodeAllOnSameLine() || context.NextNodeBlockIsOnOneLine());
+    }
+
+    function isMultilineBlockContext(context: FormattingContext): boolean {
+        return isBlockContext(context) && !(context.ContextNodeAllOnSameLine() || context.ContextNodeBlockIsOnOneLine());
+    }
+
+    function isSingleLineBlockContext(context: FormattingContext): boolean {
+        return isBlockContext(context) && (context.ContextNodeAllOnSameLine() || context.ContextNodeBlockIsOnOneLine());
+    }
+
+    function isBlockContext(context: FormattingContext): boolean {
+        return nodeIsBlockContext(context.contextNode);
+    }
+
+    function isBeforeBlockContext(context: FormattingContext): boolean {
+        return nodeIsBlockContext(context.nextTokenParent);
+    }
+
+    // IMPORTANT!!! This method must return true ONLY for nodes with open and close braces as immediate children
+    function nodeIsBlockContext(node: Node): boolean {
+        if (nodeIsTypeScriptDeclWithBlockContext(node)) {
+            // This means we are in a context that looks like a block to the user, but in the grammar is actually not a node (it's a class, module, enum, object type literal, etc).
+            return true;
+        }
+
+        switch (node.kind) {
+            case SyntaxKind.Block:
+            case SyntaxKind.CaseBlock:
+            case SyntaxKind.ObjectLiteralExpression:
+            case SyntaxKind.ModuleBlock:
+                return true;
+        }
+
+        return false;
+    }
+
+    function isFunctionDeclContext(context: FormattingContext): boolean {
+        switch (context.contextNode.kind) {
+            case SyntaxKind.FunctionDeclaration:
+            case SyntaxKind.MethodDeclaration:
+            case SyntaxKind.MethodSignature:
+            // case SyntaxKind.MemberFunctionDeclaration:
+            case SyntaxKind.GetAccessor:
+            case SyntaxKind.SetAccessor:
+            // case SyntaxKind.MethodSignature:
+            case SyntaxKind.CallSignature:
+            case SyntaxKind.FunctionExpression:
+            case SyntaxKind.Constructor:
+            case SyntaxKind.ArrowFunction:
+            // case SyntaxKind.ConstructorDeclaration:
+            // case SyntaxKind.SimpleArrowFunctionExpression:
+            // case SyntaxKind.ParenthesizedArrowFunctionExpression:
+            case SyntaxKind.InterfaceDeclaration: // This one is not truly a function, but for formatting purposes, it acts just like one
+                return true;
+        }
+
+        return false;
+    }
+
+    function isFunctionDeclarationOrFunctionExpressionContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.FunctionDeclaration || context.contextNode.kind === SyntaxKind.FunctionExpression;
+    }
+
+    function isTypeScriptDeclWithBlockContext(context: FormattingContext): boolean {
+        return nodeIsTypeScriptDeclWithBlockContext(context.contextNode);
+    }
+
+    function nodeIsTypeScriptDeclWithBlockContext(node: Node): boolean {
+        switch (node.kind) {
+            case SyntaxKind.ClassDeclaration:
+            case SyntaxKind.ClassExpression:
+            case SyntaxKind.InterfaceDeclaration:
+            case SyntaxKind.EnumDeclaration:
+            case SyntaxKind.TypeLiteral:
+            case SyntaxKind.ModuleDeclaration:
+            case SyntaxKind.ExportDeclaration:
+            case SyntaxKind.NamedExports:
+            case SyntaxKind.ImportDeclaration:
+            case SyntaxKind.NamedImports:
+                return true;
+        }
+
+        return false;
+    }
+
+    function isAfterCodeBlockContext(context: FormattingContext): boolean {
+        switch (context.currentTokenParent.kind) {
+            case SyntaxKind.ClassDeclaration:
+            case SyntaxKind.ModuleDeclaration:
+            case SyntaxKind.EnumDeclaration:
+            case SyntaxKind.CatchClause:
+            case SyntaxKind.ModuleBlock:
+            case SyntaxKind.SwitchStatement:
+                return true;
+            case SyntaxKind.Block: {
+                const blockParent = context.currentTokenParent.parent;
+                // In a codefix scenario, we can't rely on parents being set. So just always return true.
+                if (!blockParent || blockParent.kind !== SyntaxKind.ArrowFunction && blockParent.kind !== SyntaxKind.FunctionExpression) {
                     return true;
-            }
-
-            return false;
-        }
-
-        static IsFunctionDeclContext(context: FormattingContext): boolean {
-            switch (context.contextNode.kind) {
-                case SyntaxKind.FunctionDeclaration:
-                case SyntaxKind.MethodDeclaration:
-                case SyntaxKind.MethodSignature:
-                // case SyntaxKind.MemberFunctionDeclaration:
-                case SyntaxKind.GetAccessor:
-                case SyntaxKind.SetAccessor:
-                // case SyntaxKind.MethodSignature:
-                case SyntaxKind.CallSignature:
-                case SyntaxKind.FunctionExpression:
-                case SyntaxKind.Constructor:
-                case SyntaxKind.ArrowFunction:
-                // case SyntaxKind.ConstructorDeclaration:
-                // case SyntaxKind.SimpleArrowFunctionExpression:
-                // case SyntaxKind.ParenthesizedArrowFunctionExpression:
-                case SyntaxKind.InterfaceDeclaration: // This one is not truly a function, but for formatting purposes, it acts just like one
-                    return true;
-            }
-
-            return false;
-        }
-
-        static IsFunctionDeclarationOrFunctionExpressionContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.FunctionDeclaration || context.contextNode.kind === SyntaxKind.FunctionExpression;
-        }
-
-        static IsTypeScriptDeclWithBlockContext(context: FormattingContext): boolean {
-            return Rules.NodeIsTypeScriptDeclWithBlockContext(context.contextNode);
-        }
-
-        static NodeIsTypeScriptDeclWithBlockContext(node: Node): boolean {
-            switch (node.kind) {
-                case SyntaxKind.ClassDeclaration:
-                case SyntaxKind.ClassExpression:
-                case SyntaxKind.InterfaceDeclaration:
-                case SyntaxKind.EnumDeclaration:
-                case SyntaxKind.TypeLiteral:
-                case SyntaxKind.ModuleDeclaration:
-                case SyntaxKind.ExportDeclaration:
-                case SyntaxKind.NamedExports:
-                case SyntaxKind.ImportDeclaration:
-                case SyntaxKind.NamedImports:
-                    return true;
-            }
-
-            return false;
-        }
-
-        static IsAfterCodeBlockContext(context: FormattingContext): boolean {
-            switch (context.currentTokenParent.kind) {
-                case SyntaxKind.ClassDeclaration:
-                case SyntaxKind.ModuleDeclaration:
-                case SyntaxKind.EnumDeclaration:
-                case SyntaxKind.CatchClause:
-                case SyntaxKind.ModuleBlock:
-                case SyntaxKind.SwitchStatement:
-                    return true;
-                case SyntaxKind.Block: {
-                    const blockParent = context.currentTokenParent.parent;
-                    // In a codefix scenario, we can't rely on parents being set. So just always return true.
-                    if (!blockParent || blockParent.kind !== SyntaxKind.ArrowFunction && blockParent.kind !== SyntaxKind.FunctionExpression) {
-                        return true;
-                    }
                 }
             }
-            return false;
         }
+        return false;
+    }
 
-        static IsControlDeclContext(context: FormattingContext): boolean {
-            switch (context.contextNode.kind) {
-                case SyntaxKind.IfStatement:
-                case SyntaxKind.SwitchStatement:
-                case SyntaxKind.ForStatement:
-                case SyntaxKind.ForInStatement:
-                case SyntaxKind.ForOfStatement:
-                case SyntaxKind.WhileStatement:
-                case SyntaxKind.TryStatement:
-                case SyntaxKind.DoStatement:
-                case SyntaxKind.WithStatement:
-                // TODO
-                // case SyntaxKind.ElseClause:
-                case SyntaxKind.CatchClause:
-                    return true;
+    function isControlDeclContext(context: FormattingContext): boolean {
+        switch (context.contextNode.kind) {
+            case SyntaxKind.IfStatement:
+            case SyntaxKind.SwitchStatement:
+            case SyntaxKind.ForStatement:
+            case SyntaxKind.ForInStatement:
+            case SyntaxKind.ForOfStatement:
+            case SyntaxKind.WhileStatement:
+            case SyntaxKind.TryStatement:
+            case SyntaxKind.DoStatement:
+            case SyntaxKind.WithStatement:
+            // TODO
+            // case SyntaxKind.ElseClause:
+            case SyntaxKind.CatchClause:
+                return true;
 
-                default:
-                    return false;
-            }
-        }
-
-        static IsObjectContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ObjectLiteralExpression;
-        }
-
-        static IsFunctionCallContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.CallExpression;
-        }
-
-        static IsNewContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.NewExpression;
-        }
-
-        static IsFunctionCallOrNewContext(context: FormattingContext): boolean {
-            return Rules.IsFunctionCallContext(context) || Rules.IsNewContext(context);
-        }
-
-        static IsPreviousTokenNotComma(context: FormattingContext): boolean {
-            return context.currentTokenSpan.kind !== SyntaxKind.CommaToken;
-        }
-
-        static IsNextTokenNotCloseBracket(context: FormattingContext): boolean {
-            return context.nextTokenSpan.kind !== SyntaxKind.CloseBracketToken;
-        }
-
-        static IsArrowFunctionContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ArrowFunction;
-        }
-
-        static IsNonJsxSameLineTokenContext(context: FormattingContext): boolean {
-            return context.TokensAreOnSameLine() && context.contextNode.kind !== SyntaxKind.JsxText;
-        }
-
-        static IsNonJsxElementContext(context: FormattingContext): boolean {
-            return context.contextNode.kind !== SyntaxKind.JsxElement;
-        }
-
-        static IsJsxExpressionContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.JsxExpression;
-        }
-
-        static IsNextTokenParentJsxAttribute(context: FormattingContext): boolean {
-            return context.nextTokenParent.kind === SyntaxKind.JsxAttribute;
-        }
-
-        static IsJsxAttributeContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.JsxAttribute;
-        }
-
-        static IsJsxSelfClosingElementContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.JsxSelfClosingElement;
-        }
-
-        static IsNotBeforeBlockInFunctionDeclarationContext(context: FormattingContext): boolean {
-            return !Rules.IsFunctionDeclContext(context) && !Rules.IsBeforeBlockContext(context);
-        }
-
-        static IsEndOfDecoratorContextOnSameLine(context: FormattingContext): boolean {
-            return context.TokensAreOnSameLine() &&
-                context.contextNode.decorators &&
-                Rules.NodeIsInDecoratorContext(context.currentTokenParent) &&
-                !Rules.NodeIsInDecoratorContext(context.nextTokenParent);
-        }
-
-        static NodeIsInDecoratorContext(node: Node): boolean {
-            while (isPartOfExpression(node)) {
-                node = node.parent;
-            }
-            return node.kind === SyntaxKind.Decorator;
-        }
-
-        static IsStartOfVariableDeclarationList(context: FormattingContext): boolean {
-            return context.currentTokenParent.kind === SyntaxKind.VariableDeclarationList &&
-                context.currentTokenParent.getStart(context.sourceFile) === context.currentTokenSpan.pos;
-        }
-
-        static IsNotFormatOnEnter(context: FormattingContext): boolean {
-            return context.formattingRequestKind !== FormattingRequestKind.FormatOnEnter;
-        }
-
-        static IsModuleDeclContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ModuleDeclaration;
-        }
-
-        static IsObjectTypeContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.TypeLiteral; // && context.contextNode.parent.kind !== SyntaxKind.InterfaceDeclaration;
-        }
-
-        static IsConstructorSignatureContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.ConstructSignature;
-        }
-
-        static IsTypeArgumentOrParameterOrAssertion(token: TextRangeWithKind, parent: Node): boolean {
-            if (token.kind !== SyntaxKind.LessThanToken && token.kind !== SyntaxKind.GreaterThanToken) {
+            default:
                 return false;
-            }
-            switch (parent.kind) {
-                case SyntaxKind.TypeReference:
-                case SyntaxKind.TypeAssertionExpression:
-                case SyntaxKind.TypeAliasDeclaration:
-                case SyntaxKind.ClassDeclaration:
-                case SyntaxKind.ClassExpression:
-                case SyntaxKind.InterfaceDeclaration:
-                case SyntaxKind.FunctionDeclaration:
-                case SyntaxKind.FunctionExpression:
-                case SyntaxKind.ArrowFunction:
-                case SyntaxKind.MethodDeclaration:
-                case SyntaxKind.MethodSignature:
-                case SyntaxKind.CallSignature:
-                case SyntaxKind.ConstructSignature:
-                case SyntaxKind.CallExpression:
-                case SyntaxKind.NewExpression:
-                case SyntaxKind.ExpressionWithTypeArguments:
-                    return true;
-                default:
-                    return false;
-
-            }
-        }
-
-        static IsTypeArgumentOrParameterOrAssertionContext(context: FormattingContext): boolean {
-            return Rules.IsTypeArgumentOrParameterOrAssertion(context.currentTokenSpan, context.currentTokenParent) ||
-                Rules.IsTypeArgumentOrParameterOrAssertion(context.nextTokenSpan, context.nextTokenParent);
-        }
-
-        static IsTypeAssertionContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.TypeAssertionExpression;
-        }
-
-        static IsVoidOpContext(context: FormattingContext): boolean {
-            return context.currentTokenSpan.kind === SyntaxKind.VoidKeyword && context.currentTokenParent.kind === SyntaxKind.VoidExpression;
-        }
-
-        static IsYieldOrYieldStarWithOperand(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.YieldExpression && (<YieldExpression>context.contextNode).expression !== undefined;
-        }
-
-        static IsNonNullAssertionContext(context: FormattingContext): boolean {
-            return context.contextNode.kind === SyntaxKind.NonNullExpression;
         }
     }
-}
\ No newline at end of file
+
+    function isObjectContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ObjectLiteralExpression;
+    }
+
+    function isFunctionCallContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.CallExpression;
+    }
+
+    function isNewContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.NewExpression;
+    }
+
+    function isFunctionCallOrNewContext(context: FormattingContext): boolean {
+        return isFunctionCallContext(context) || isNewContext(context);
+    }
+
+    function isPreviousTokenNotComma(context: FormattingContext): boolean {
+        return context.currentTokenSpan.kind !== SyntaxKind.CommaToken;
+    }
+
+    function isNextTokenNotCloseBracket(context: FormattingContext): boolean {
+        return context.nextTokenSpan.kind !== SyntaxKind.CloseBracketToken;
+    }
+
+    function isArrowFunctionContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ArrowFunction;
+    }
+
+    function isNonJsxSameLineTokenContext(context: FormattingContext): boolean {
+        return context.TokensAreOnSameLine() && context.contextNode.kind !== SyntaxKind.JsxText;
+    }
+
+    function isNonJsxElementContext(context: FormattingContext): boolean {
+        return context.contextNode.kind !== SyntaxKind.JsxElement;
+    }
+
+    function isJsxExpressionContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.JsxExpression;
+    }
+
+    function isNextTokenParentJsxAttribute(context: FormattingContext): boolean {
+        return context.nextTokenParent.kind === SyntaxKind.JsxAttribute;
+    }
+
+    function isJsxAttributeContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.JsxAttribute;
+    }
+
+    function isJsxSelfClosingElementContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.JsxSelfClosingElement;
+    }
+
+    function isNotBeforeBlockInFunctionDeclarationContext(context: FormattingContext): boolean {
+        return !isFunctionDeclContext(context) && !isBeforeBlockContext(context);
+    }
+
+    function isEndOfDecoratorContextOnSameLine(context: FormattingContext): boolean {
+        return context.TokensAreOnSameLine() &&
+            context.contextNode.decorators &&
+            nodeIsInDecoratorContext(context.currentTokenParent) &&
+            !nodeIsInDecoratorContext(context.nextTokenParent);
+    }
+
+    function nodeIsInDecoratorContext(node: Node): boolean {
+        while (isExpressionNode(node)) {
+            node = node.parent;
+        }
+        return node.kind === SyntaxKind.Decorator;
+    }
+
+    function isStartOfVariableDeclarationList(context: FormattingContext): boolean {
+        return context.currentTokenParent.kind === SyntaxKind.VariableDeclarationList &&
+            context.currentTokenParent.getStart(context.sourceFile) === context.currentTokenSpan.pos;
+    }
+
+    function isNotFormatOnEnter(context: FormattingContext): boolean {
+        return context.formattingRequestKind !== FormattingRequestKind.FormatOnEnter;
+    }
+
+    function isModuleDeclContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ModuleDeclaration;
+    }
+
+    function isObjectTypeContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.TypeLiteral; // && context.contextNode.parent.kind !== SyntaxKind.InterfaceDeclaration;
+    }
+
+    function isConstructorSignatureContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.ConstructSignature;
+    }
+
+    function isTypeArgumentOrParameterOrAssertion(token: TextRangeWithKind, parent: Node): boolean {
+        if (token.kind !== SyntaxKind.LessThanToken && token.kind !== SyntaxKind.GreaterThanToken) {
+            return false;
+        }
+        switch (parent.kind) {
+            case SyntaxKind.TypeReference:
+            case SyntaxKind.TypeAssertionExpression:
+            case SyntaxKind.TypeAliasDeclaration:
+            case SyntaxKind.ClassDeclaration:
+            case SyntaxKind.ClassExpression:
+            case SyntaxKind.InterfaceDeclaration:
+            case SyntaxKind.FunctionDeclaration:
+            case SyntaxKind.FunctionExpression:
+            case SyntaxKind.ArrowFunction:
+            case SyntaxKind.MethodDeclaration:
+            case SyntaxKind.MethodSignature:
+            case SyntaxKind.CallSignature:
+            case SyntaxKind.ConstructSignature:
+            case SyntaxKind.CallExpression:
+            case SyntaxKind.NewExpression:
+            case SyntaxKind.ExpressionWithTypeArguments:
+                return true;
+            default:
+                return false;
+
+        }
+    }
+
+    function isTypeArgumentOrParameterOrAssertionContext(context: FormattingContext): boolean {
+        return isTypeArgumentOrParameterOrAssertion(context.currentTokenSpan, context.currentTokenParent) ||
+            isTypeArgumentOrParameterOrAssertion(context.nextTokenSpan, context.nextTokenParent);
+    }
+
+    function isTypeAssertionContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.TypeAssertionExpression;
+    }
+
+    function isVoidOpContext(context: FormattingContext): boolean {
+        return context.currentTokenSpan.kind === SyntaxKind.VoidKeyword && context.currentTokenParent.kind === SyntaxKind.VoidExpression;
+    }
+
+    function isYieldOrYieldStarWithOperand(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.YieldExpression && (<YieldExpression>context.contextNode).expression !== undefined;
+    }
+
+    function isNonNullAssertionContext(context: FormattingContext): boolean {
+        return context.contextNode.kind === SyntaxKind.NonNullExpression;
+    }
+}
diff --git a/src/services/formatting/rulesMap.ts b/src/services/formatting/rulesMap.ts
index d1f6e4724f7..d44e47a763a 100644
--- a/src/services/formatting/rulesMap.ts
+++ b/src/services/formatting/rulesMap.ts
@@ -1,156 +1,107 @@
-///<reference path='references.ts' />
+/// <reference path="rules.ts" />
 
 /* @internal */
 namespace ts.formatting {
-    export class RulesMap {
-        public map: RulesBucket[];
-        public mapRowLength: number;
-
-        constructor(rules: ReadonlyArray<Rule>) {
-            this.mapRowLength = SyntaxKind.LastToken + 1;
-            this.map = new Array<RulesBucket>(this.mapRowLength * this.mapRowLength);
-
-            // This array is used only during construction of the rulesbucket in the map
-            const rulesBucketConstructionStateList: RulesBucketConstructionState[] = new Array<RulesBucketConstructionState>(this.map.length);
-            for (const rule of rules) {
-                this.FillRule(rule, rulesBucketConstructionStateList);
-            }
-        }
-
-        private GetRuleBucketIndex(row: number, column: number): number {
-            Debug.assert(row <= SyntaxKind.LastKeyword && column <= SyntaxKind.LastKeyword, "Must compute formatting context from tokens");
-            return (row * this.mapRowLength) + column;
-        }
-
-        private FillRule(rule: Rule, rulesBucketConstructionStateList: RulesBucketConstructionState[]): void {
-            const specificRule = rule.Descriptor.LeftTokenRange.isSpecific() && rule.Descriptor.RightTokenRange.isSpecific();
-
-            rule.Descriptor.LeftTokenRange.GetTokens().forEach((left) => {
-                rule.Descriptor.RightTokenRange.GetTokens().forEach((right) => {
-                    const rulesBucketIndex = this.GetRuleBucketIndex(left, right);
-
-                    let rulesBucket = this.map[rulesBucketIndex];
-                    if (rulesBucket === undefined) {
-                        rulesBucket = this.map[rulesBucketIndex] = new RulesBucket();
-                    }
-
-                    rulesBucket.AddRule(rule, specificRule, rulesBucketConstructionStateList, rulesBucketIndex);
-                });
-            });
-        }
-
-        public GetRule(context: FormattingContext): Rule | undefined {
-            const bucketIndex = this.GetRuleBucketIndex(context.currentTokenSpan.kind, context.nextTokenSpan.kind);
-            const bucket = this.map[bucketIndex];
-            if (bucket) {
-                for (const rule of bucket.Rules()) {
-                    if (rule.Operation.Context.InContext(context)) {
-                        return rule;
-                    }
-                }
-            }
-            return undefined;
-        }
+    export function getFormatContext(options: FormatCodeSettings): formatting.FormatContext {
+        return { options, getRule: getRulesMap() };
     }
 
-    const MaskBitSize = 5;
-    const Mask = 0x1f;
+    let rulesMapCache: RulesMap | undefined;
+
+    function getRulesMap(): RulesMap {
+        if (rulesMapCache === undefined) {
+            rulesMapCache = createRulesMap(getAllRules());
+        }
+        return rulesMapCache;
+    }
+
+    export type RulesMap = (context: FormattingContext) => Rule | undefined;
+    function createRulesMap(rules: ReadonlyArray<RuleSpec>): RulesMap {
+        const map = buildMap(rules);
+        return context => {
+            const bucket = map[getRuleBucketIndex(context.currentTokenSpan.kind, context.nextTokenSpan.kind)];
+            return bucket && find(bucket, rule => every(rule.context, c => c(context)));
+        };
+    }
+
+    function buildMap(rules: ReadonlyArray<RuleSpec>): ReadonlyArray<ReadonlyArray<Rule>> {
+        // Map from bucket index to array of rules
+        const map: Rule[][] = new Array(mapRowLength * mapRowLength);
+        // This array is used only during construction of the rulesbucket in the map
+        const rulesBucketConstructionStateList = new Array<number>(map.length);
+        for (const rule of rules) {
+            const specificRule = rule.leftTokenRange.isSpecific && rule.rightTokenRange.isSpecific;
+
+            for (const left of rule.leftTokenRange.tokens) {
+                for (const right of rule.rightTokenRange.tokens) {
+                    const index = getRuleBucketIndex(left, right);
+                    let rulesBucket = map[index];
+                    if (rulesBucket === undefined) {
+                        rulesBucket = map[index] = [];
+                    }
+                    addRule(rulesBucket, rule.rule, specificRule, rulesBucketConstructionStateList, index);
+                }
+            }
+        }
+        return map;
+    }
+
+    function getRuleBucketIndex(row: number, column: number): number {
+        Debug.assert(row <= SyntaxKind.LastKeyword && column <= SyntaxKind.LastKeyword, "Must compute formatting context from tokens");
+        return (row * mapRowLength) + column;
+    }
+
+    const maskBitSize = 5;
+    const mask = 0b11111; // MaskBitSize bits
+    const mapRowLength = SyntaxKind.LastToken + 1;
 
     enum RulesPosition {
         IgnoreRulesSpecific = 0,
-        IgnoreRulesAny = MaskBitSize * 1,
-        ContextRulesSpecific = MaskBitSize * 2,
-        ContextRulesAny = MaskBitSize * 3,
-        NoContextRulesSpecific = MaskBitSize * 4,
-        NoContextRulesAny = MaskBitSize * 5
+        IgnoreRulesAny = maskBitSize * 1,
+        ContextRulesSpecific = maskBitSize * 2,
+        ContextRulesAny = maskBitSize * 3,
+        NoContextRulesSpecific = maskBitSize * 4,
+        NoContextRulesAny = maskBitSize * 5
     }
 
-    export class RulesBucketConstructionState {
-        private rulesInsertionIndexBitmap: number;
-
-        constructor() {
-            //// The Rules list contains all the inserted rules into a rulebucket in the following order:
-            ////    1- Ignore rules with specific token combination
-            ////    2- Ignore rules with any token combination
-            ////    3- Context rules with specific token combination
-            ////    4- Context rules with any token combination
-            ////    5- Non-context rules with specific token combination
-            ////    6- Non-context rules with any token combination
-            ////
-            //// The member rulesInsertionIndexBitmap is used to describe the number of rules
-            //// in each sub-bucket (above) hence can be used to know the index of where to insert
-            //// the next rule. It's a bitmap which contains 6 different sections each is given 5 bits.
-            ////
-            //// Example:
-            //// In order to insert a rule to the end of sub-bucket (3), we get the index by adding
-            //// the values in the bitmap segments 3rd, 2nd, and 1st.
-            this.rulesInsertionIndexBitmap = 0;
-        }
-
-        public GetInsertionIndex(maskPosition: RulesPosition): number {
-            let index = 0;
-
-            let pos = 0;
-            let indexBitmap = this.rulesInsertionIndexBitmap;
-
-            while (pos <= maskPosition) {
-                index += (indexBitmap & Mask);
-                indexBitmap >>= MaskBitSize;
-                pos += MaskBitSize;
-            }
-
-            return index;
-        }
-
-        public IncreaseInsertionIndex(maskPosition: RulesPosition): void {
-            let value = (this.rulesInsertionIndexBitmap >> maskPosition) & Mask;
-            value++;
-            Debug.assert((value & Mask) === value, "Adding more rules into the sub-bucket than allowed. Maximum allowed is 32 rules.");
-
-            let temp = this.rulesInsertionIndexBitmap & ~(Mask << maskPosition);
-            temp |= value << maskPosition;
-
-            this.rulesInsertionIndexBitmap = temp;
-        }
+    // The Rules list contains all the inserted rules into a rulebucket in the following order:
+    //    1- Ignore rules with specific token combination
+    //    2- Ignore rules with any token combination
+    //    3- Context rules with specific token combination
+    //    4- Context rules with any token combination
+    //    5- Non-context rules with specific token combination
+    //    6- Non-context rules with any token combination
+    //
+    // The member rulesInsertionIndexBitmap is used to describe the number of rules
+    // in each sub-bucket (above) hence can be used to know the index of where to insert
+    // the next rule. It's a bitmap which contains 6 different sections each is given 5 bits.
+    //
+    // Example:
+    // In order to insert a rule to the end of sub-bucket (3), we get the index by adding
+    // the values in the bitmap segments 3rd, 2nd, and 1st.
+    function addRule(rules: Rule[], rule: Rule, specificTokens: boolean, constructionState: number[], rulesBucketIndex: number): void {
+        const position = rule.action === RuleAction.Ignore
+            ? specificTokens ? RulesPosition.IgnoreRulesSpecific : RulesPosition.IgnoreRulesAny
+            : rule.context !== anyContext
+            ? specificTokens ? RulesPosition.ContextRulesSpecific : RulesPosition.ContextRulesAny
+            : specificTokens ? RulesPosition.NoContextRulesSpecific : RulesPosition.NoContextRulesAny;
+        const state = constructionState[rulesBucketIndex] || 0;
+        rules.splice(getInsertionIndex(state, position), 0, rule);
+        constructionState[rulesBucketIndex] = increaseInsertionIndex(state, position);
     }
 
-    export class RulesBucket {
-        private rules: Rule[];
-
-        constructor() {
-            this.rules = [];
+    function getInsertionIndex(indexBitmap: number, maskPosition: RulesPosition) {
+        let index = 0;
+        for (let pos = 0; pos <= maskPosition; pos += maskBitSize) {
+            index += indexBitmap & mask;
+            indexBitmap >>= maskBitSize;
         }
+        return index;
+    }
 
-        public Rules(): Rule[] {
-            return this.rules;
-        }
-
-        public AddRule(rule: Rule, specificTokens: boolean, constructionState: RulesBucketConstructionState[], rulesBucketIndex: number): void {
-            let position: RulesPosition;
-
-            if (rule.Operation.Action === RuleAction.Ignore) {
-                position = specificTokens ?
-                    RulesPosition.IgnoreRulesSpecific :
-                    RulesPosition.IgnoreRulesAny;
-            }
-            else if (!rule.Operation.Context.IsAny()) {
-                position = specificTokens ?
-                    RulesPosition.ContextRulesSpecific :
-                    RulesPosition.ContextRulesAny;
-            }
-            else {
-                position = specificTokens ?
-                    RulesPosition.NoContextRulesSpecific :
-                    RulesPosition.NoContextRulesAny;
-            }
-
-            let state = constructionState[rulesBucketIndex];
-            if (state === undefined) {
-                state = constructionState[rulesBucketIndex] = new RulesBucketConstructionState();
-            }
-            const index = state.GetInsertionIndex(position);
-            this.rules.splice(index, 0, rule);
-            state.IncreaseInsertionIndex(position);
-        }
+    function increaseInsertionIndex(indexBitmap: number, maskPosition: RulesPosition): number {
+        const value = ((indexBitmap >> maskPosition) & mask) + 1;
+        Debug.assert((value & mask) === value, "Adding more rules into the sub-bucket than allowed. Maximum allowed is 32 rules.");
+        return (indexBitmap & ~(mask << maskPosition)) | (value << maskPosition);
     }
 }
\ No newline at end of file
diff --git a/src/services/formatting/rulesProvider.ts b/src/services/formatting/rulesProvider.ts
deleted file mode 100644
index fcf08541890..00000000000
--- a/src/services/formatting/rulesProvider.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-/// <reference path="references.ts"/>
-
-/* @internal */
-namespace ts.formatting {
-    export class RulesProvider {
-        private globalRules: Rules;
-        private options: ts.FormatCodeSettings;
-        private rulesMap: RulesMap;
-
-        constructor() {
-            this.globalRules = new Rules();
-            const activeRules = this.globalRules.HighPriorityCommonRules.concat(this.globalRules.UserConfigurableRules).concat(this.globalRules.LowPriorityCommonRules);
-            this.rulesMap = new RulesMap(activeRules);
-        }
-
-        public getRulesMap() {
-            return this.rulesMap;
-        }
-
-        public getFormatOptions(): Readonly<ts.FormatCodeSettings> {
-            return this.options;
-        }
-
-        public ensureUpToDate(options: ts.FormatCodeSettings) {
-            if (!this.options || !ts.compareDataObjects(this.options, options)) {
-                this.options = ts.clone(options);
-            }
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/services/formatting/smartIndenter.ts b/src/services/formatting/smartIndenter.ts
index 7701cff182c..5afe4cb1d31 100644
--- a/src/services/formatting/smartIndenter.ts
+++ b/src/services/formatting/smartIndenter.ts
@@ -1,5 +1,3 @@
-///<reference path='..\services.ts' />
-
 /* @internal */
 namespace ts.formatting {
     export namespace SmartIndenter {
diff --git a/src/services/formatting/tokenRange.ts b/src/services/formatting/tokenRange.ts
deleted file mode 100644
index 29855279e25..00000000000
--- a/src/services/formatting/tokenRange.ts
+++ /dev/null
@@ -1,123 +0,0 @@
-///<reference path='references.ts' />
-
-/* @internal */
-namespace ts.formatting {
-    export namespace Shared {
-        const allTokens: SyntaxKind[] = [];
-        for (let token = SyntaxKind.FirstToken; token <= SyntaxKind.LastToken; token++) {
-            allTokens.push(token);
-        }
-
-        class TokenValuesAccess implements TokenRange {
-            constructor(private readonly tokens: SyntaxKind[] = []) { }
-
-            public GetTokens(): SyntaxKind[] {
-                return this.tokens;
-            }
-
-            public Contains(token: SyntaxKind): boolean {
-                return this.tokens.indexOf(token) >= 0;
-            }
-
-            public isSpecific() { return true; }
-        }
-
-        class TokenSingleValueAccess implements TokenRange {
-            constructor(private readonly token: SyntaxKind) {}
-
-            public GetTokens(): SyntaxKind[] {
-                return [this.token];
-            }
-
-            public Contains(tokenValue: SyntaxKind): boolean {
-                return tokenValue === this.token;
-            }
-
-            public isSpecific() { return true; }
-        }
-
-        class TokenAllAccess implements TokenRange {
-            public GetTokens(): SyntaxKind[] {
-                return allTokens;
-            }
-
-            public Contains(): boolean {
-                return true;
-            }
-
-            public toString(): string {
-                return "[allTokens]";
-            }
-
-            public isSpecific() { return false; }
-        }
-
-        class TokenAllExceptAccess implements TokenRange {
-            constructor(private readonly except: SyntaxKind) {}
-
-            public GetTokens(): SyntaxKind[] {
-                return allTokens.filter(t => t !== this.except);
-            }
-
-            public Contains(token: SyntaxKind): boolean {
-                return token !== this.except;
-            }
-
-            public isSpecific() { return false; }
-        }
-
-        export interface TokenRange {
-            GetTokens(): SyntaxKind[];
-            Contains(token: SyntaxKind): boolean;
-            isSpecific(): boolean;
-        }
-
-        export namespace TokenRange {
-            export function FromToken(token: SyntaxKind): TokenRange {
-                return new TokenSingleValueAccess(token);
-            }
-
-            export function FromTokens(tokens: SyntaxKind[]): TokenRange {
-                return new TokenValuesAccess(tokens);
-            }
-
-            export function FromRange(from: SyntaxKind, to: SyntaxKind, except: SyntaxKind[] = []): TokenRange {
-                const tokens: SyntaxKind[] = [];
-                for (let token = from; token <= to; token++) {
-                    if (ts.indexOf(except, token) < 0) {
-                        tokens.push(token);
-                    }
-                }
-                return new TokenValuesAccess(tokens);
-            }
-
-            export function AnyExcept(token: SyntaxKind): TokenRange {
-                return new TokenAllExceptAccess(token);
-            }
-
-            export const Any: TokenRange = new TokenAllAccess();
-            export const AnyIncludingMultilineComments = TokenRange.FromTokens([...allTokens, SyntaxKind.MultiLineCommentTrivia]);
-            export const Keywords = TokenRange.FromRange(SyntaxKind.FirstKeyword, SyntaxKind.LastKeyword);
-            export const BinaryOperators = TokenRange.FromRange(SyntaxKind.FirstBinaryOperator, SyntaxKind.LastBinaryOperator);
-            export const BinaryKeywordOperators = TokenRange.FromTokens([
-                SyntaxKind.InKeyword, SyntaxKind.InstanceOfKeyword, SyntaxKind.OfKeyword, SyntaxKind.AsKeyword, SyntaxKind.IsKeyword]);
-            export const UnaryPrefixOperators = TokenRange.FromTokens([
-                SyntaxKind.PlusPlusToken, SyntaxKind.MinusMinusToken, SyntaxKind.TildeToken, SyntaxKind.ExclamationToken]);
-            export const UnaryPrefixExpressions = TokenRange.FromTokens([
-                SyntaxKind.NumericLiteral, SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.OpenBracketToken,
-                SyntaxKind.OpenBraceToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
-            export const UnaryPreincrementExpressions = TokenRange.FromTokens([
-                SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
-            export const UnaryPostincrementExpressions = TokenRange.FromTokens([
-                SyntaxKind.Identifier, SyntaxKind.CloseParenToken, SyntaxKind.CloseBracketToken, SyntaxKind.NewKeyword]);
-            export const UnaryPredecrementExpressions = TokenRange.FromTokens([
-                SyntaxKind.Identifier, SyntaxKind.OpenParenToken, SyntaxKind.ThisKeyword, SyntaxKind.NewKeyword]);
-            export const UnaryPostdecrementExpressions = TokenRange.FromTokens([
-                SyntaxKind.Identifier, SyntaxKind.CloseParenToken, SyntaxKind.CloseBracketToken, SyntaxKind.NewKeyword]);
-            export const Comments = TokenRange.FromTokens([SyntaxKind.SingleLineCommentTrivia, SyntaxKind.MultiLineCommentTrivia]);
-            export const TypeNames = TokenRange.FromTokens([
-                SyntaxKind.Identifier, SyntaxKind.NumberKeyword, SyntaxKind.StringKeyword, SyntaxKind.BooleanKeyword,
-                SyntaxKind.SymbolKeyword, SyntaxKind.VoidKeyword, SyntaxKind.AnyKeyword]);
-        }
-    }
-}
diff --git a/src/services/goToDefinition.ts b/src/services/goToDefinition.ts
index cb2be7d484c..35f4d079e29 100644
--- a/src/services/goToDefinition.ts
+++ b/src/services/goToDefinition.ts
@@ -88,7 +88,7 @@ namespace ts.GoToDefinition {
         //      }
         //      bar<Test>(({pr/*goto*/op1})=>{});
         if (isPropertyName(node) && isBindingElement(node.parent) && isObjectBindingPattern(node.parent.parent) &&
-             (node === (node.parent.propertyName || node.parent.name))) {
+            (node === (node.parent.propertyName || node.parent.name))) {
             const type = typeChecker.getTypeAtLocation(node.parent.parent);
             if (type) {
                 const propSymbols = getPropertySymbolsFromType(type, node);
@@ -149,6 +149,28 @@ namespace ts.GoToDefinition {
         return getDefinitionFromSymbol(typeChecker, type.symbol, node);
     }
 
+    export function getDefinitionAndBoundSpan(program: Program, sourceFile: SourceFile, position: number): DefinitionInfoAndBoundSpan {
+        const definitions = getDefinitionAtPosition(program, sourceFile, position);
+
+        if (!definitions || definitions.length === 0) {
+            return undefined;
+        }
+
+        // Check if position is on triple slash reference.
+        const comment = findReferenceInPosition(sourceFile.referencedFiles, position) || findReferenceInPosition(sourceFile.typeReferenceDirectives, position);
+        if (comment) {
+            return {
+                definitions,
+                textSpan: createTextSpanFromBounds(comment.pos, comment.end)
+            };
+        }
+
+        const node = getTouchingPropertyName(sourceFile, position, /*includeJsDocComment*/ true);
+        const textSpan = createTextSpan(node.getStart(), node.getWidth());
+
+        return { definitions, textSpan };
+    }
+
     // Go to the original declaration for cases:
     //
     //   (1) when the aliased symbol was declared in the location(parent).
diff --git a/src/services/jsDoc.ts b/src/services/jsDoc.ts
index 3e9913fc6c7..79b08780226 100644
--- a/src/services/jsDoc.ts
+++ b/src/services/jsDoc.ts
@@ -1,5 +1,6 @@
 /* @internal */
 namespace ts.JsDoc {
+    const singleLineTemplate = { newText: "/** */", caretOffset: 3 };
     const jsDocTagNames = [
         "augments",
         "author",
@@ -19,6 +20,7 @@ namespace ts.JsDoc {
         "fileOverview",
         "function",
         "ignore",
+        "inheritDoc",
         "inner",
         "lends",
         "link",
@@ -65,19 +67,44 @@ namespace ts.JsDoc {
         return documentationComment;
     }
 
-    export function getJsDocTagsFromDeclarations(declarations?: Declaration[]) {
+    export function getJsDocTagsFromDeclarations(declarations?: Declaration[]): JSDocTagInfo[] {
         // Only collect doc comments from duplicate declarations once.
         const tags: JSDocTagInfo[] = [];
         forEachUnique(declarations, declaration => {
             for (const tag of getJSDocTags(declaration)) {
-                if (tag.kind === SyntaxKind.JSDocTag) {
-                    tags.push({ name: tag.tagName.text, text: tag.comment });
-                }
+                tags.push({ name: tag.tagName.text, text: getCommentText(tag) });
             }
         });
         return tags;
     }
 
+    function getCommentText(tag: JSDocTag): string {
+        const { comment } = tag;
+        switch (tag.kind) {
+            case SyntaxKind.JSDocAugmentsTag:
+                return withNode((tag as JSDocAugmentsTag).class);
+            case SyntaxKind.JSDocTemplateTag:
+                return withList((tag as JSDocTemplateTag).typeParameters);
+            case SyntaxKind.JSDocTypeTag:
+                return withNode((tag as JSDocTypeTag).typeExpression);
+            case SyntaxKind.JSDocTypedefTag:
+            case SyntaxKind.JSDocPropertyTag:
+            case SyntaxKind.JSDocParameterTag:
+                const { name } = tag as JSDocTypedefTag | JSDocPropertyTag | JSDocParameterTag;
+                return name ? withNode(name) : comment;
+            default:
+                return comment;
+        }
+
+        function withNode(node: Node) {
+            return `${node.getText()} ${comment}`;
+        }
+
+        function withList(list: NodeArray<Node>): string {
+            return `${list.map(x => x.getText())} ${comment}`;
+        }
+    }
+
     /**
      * Iterates through 'array' by index and performs the callback on each element of array until the callback
      * returns a truthy value, then returns that value.
@@ -170,13 +197,9 @@ namespace ts.JsDoc {
     /**
      * Checks if position points to a valid position to add JSDoc comments, and if so,
      * returns the appropriate template. Otherwise returns an empty string.
-     * Valid positions are
-     *      - outside of comments, statements, and expressions, and
-     *      - preceding a:
-     *          - function/constructor/method declaration
-     *          - class declarations
-     *          - variable statements
-     *          - namespace declarations
+     * Invalid positions are
+     *      - within comments, strings (including template literals and regex), and JSXText
+     *      - within a token
      *
      * Hosts should ideally check that:
      * - The line is all whitespace up to 'position' before performing the insertion.
@@ -187,7 +210,8 @@ namespace ts.JsDoc {
      * @param position The (character-indexed) position in the file where the check should
      * be performed.
      */
-    export function getDocCommentTemplateAtPosition(newLine: string, sourceFile: SourceFile, position: number): TextInsertion {
+
+    export function getDocCommentTemplateAtPosition(newLine: string, sourceFile: SourceFile, position: number): TextInsertion | undefined {
         // Check if in a context where we don't want to perform any insertion
         if (isInString(sourceFile, position) || isInComment(sourceFile, position) || hasDocComment(sourceFile, position)) {
             return undefined;
@@ -201,13 +225,21 @@ namespace ts.JsDoc {
 
         const commentOwnerInfo = getCommentOwnerInfo(tokenAtPos);
         if (!commentOwnerInfo) {
-            return undefined;
+            // if climbing the tree did not find a declaration with parameters, complete to a single line comment
+            return singleLineTemplate;
         }
         const { commentOwner, parameters } = commentOwnerInfo;
-        if (commentOwner.getStart() < position) {
+
+        if (commentOwner.kind === SyntaxKind.JsxText) {
             return undefined;
         }
 
+        if (commentOwner.getStart() < position || parameters.length === 0) {
+            // if climbing the tree found a declaration with parameters but the request was made inside it
+            // or if there are no parameters, complete to a single line comment
+            return singleLineTemplate;
+        }
+
         const posLineAndChar = sourceFile.getLineAndCharacterOfPosition(position);
         const lineStart = sourceFile.getLineStarts()[posLineAndChar.line];
 
@@ -215,21 +247,11 @@ namespace ts.JsDoc {
         const indentationStr = sourceFile.text.substr(lineStart, posLineAndChar.character).replace(/\S/i, () => " ");
         const isJavaScriptFile = hasJavaScriptFileExtension(sourceFile.fileName);
 
-        let docParams = "";
-        if (parameters) {
-            for (let i = 0; i < parameters.length; i++) {
-                const currentName = parameters[i].name;
-                const paramName = currentName.kind === SyntaxKind.Identifier ?
-                    (<Identifier>currentName).escapedText :
-                    "param" + i;
-                if (isJavaScriptFile) {
-                    docParams += `${indentationStr} * @param {any} ${paramName}${newLine}`;
-                }
-                else {
-                    docParams += `${indentationStr} * @param ${paramName}${newLine}`;
-                }
-            }
-        }
+        const docParams = parameters.map(({name}, i) => {
+            const nameText = isIdentifier(name) ? name.text : `param${i}`;
+            const type = isJavaScriptFile ? "{any} " : "";
+            return `${indentationStr} * @param ${type}${nameText}${newLine}`;
+        }).join("");
 
         // A doc comment consists of the following
         // * The opening comment line
@@ -251,43 +273,30 @@ namespace ts.JsDoc {
 
     interface CommentOwnerInfo {
         readonly commentOwner: Node;
-        readonly parameters?: ReadonlyArray<ParameterDeclaration>;
+        readonly parameters: ReadonlyArray<ParameterDeclaration>;
     }
     function getCommentOwnerInfo(tokenAtPos: Node): CommentOwnerInfo | undefined {
-        // TODO: add support for:
-        // - enums/enum members
-        // - interfaces
-        // - property declarations
-        // - potentially property assignments
         for (let commentOwner = tokenAtPos; commentOwner; commentOwner = commentOwner.parent) {
             switch (commentOwner.kind) {
                 case SyntaxKind.FunctionDeclaration:
                 case SyntaxKind.MethodDeclaration:
                 case SyntaxKind.Constructor:
-                    const { parameters } = commentOwner as FunctionDeclaration | MethodDeclaration | ConstructorDeclaration;
+                case SyntaxKind.MethodSignature:
+                    const { parameters } = commentOwner as FunctionDeclaration | MethodDeclaration | ConstructorDeclaration | MethodSignature;
                     return { commentOwner, parameters };
 
-                case SyntaxKind.ClassDeclaration:
-                    return { commentOwner };
-
                 case SyntaxKind.VariableStatement: {
                     const varStatement = <VariableStatement>commentOwner;
                     const varDeclarations = varStatement.declarationList.declarations;
                     const parameters = varDeclarations.length === 1 && varDeclarations[0].initializer
                         ? getParametersFromRightHandSideOfAssignment(varDeclarations[0].initializer)
                         : undefined;
-                    return { commentOwner, parameters };
+                    return parameters ? { commentOwner, parameters } : undefined;
                 }
 
                 case SyntaxKind.SourceFile:
                     return undefined;
 
-                case SyntaxKind.ModuleDeclaration:
-                    // If in walking up the tree, we hit a a nested namespace declaration,
-                    // then we must be somewhere within a dotted namespace name; however we don't
-                    // want to give back a JSDoc template for the 'b' or 'c' in 'namespace a.b.c { }'.
-                    return commentOwner.parent.kind === SyntaxKind.ModuleDeclaration ? undefined : { commentOwner };
-
                 case SyntaxKind.BinaryExpression: {
                     const be = commentOwner as BinaryExpression;
                     if (getSpecialPropertyAssignmentKind(be) === ts.SpecialPropertyAssignmentKind.None) {
@@ -296,6 +305,11 @@ namespace ts.JsDoc {
                     const parameters = isFunctionLike(be.right) ? be.right.parameters : emptyArray;
                     return { commentOwner, parameters };
                 }
+
+                case SyntaxKind.JsxText: {
+                    const parameters: ReadonlyArray<ParameterDeclaration> = emptyArray;
+                    return { commentOwner, parameters };
+                }
             }
         }
     }
diff --git a/src/services/jsTyping.ts b/src/services/jsTyping.ts
index e31201b951f..1c2f87fa428 100644
--- a/src/services/jsTyping.ts
+++ b/src/services/jsTyping.ts
@@ -115,7 +115,10 @@ namespace ts.JsTyping {
 
         // add typings for unresolved imports
         if (unresolvedImports) {
-            const module = deduplicate(unresolvedImports.map(moduleId => nodeCoreModules.has(moduleId) ? "node" : moduleId));
+            const module = deduplicate(
+                unresolvedImports.map(moduleId => nodeCoreModules.has(moduleId) ? "node" : moduleId),
+                equateStringsCaseSensitive,
+                compareStringsCaseSensitive);
             addInferredTypings(module, "Inferred typings from unresolved imports");
         }
         // Add the cached typing locations for inferred typings that are already installed
@@ -257,7 +260,7 @@ namespace ts.JsTyping {
         NameContainsNonURISafeCharacters
     }
 
-    const MaxPackageNameLength = 214;
+    const maxPackageNameLength = 214;
 
     /**
      * Validates package name using rules defined at https://docs.npmjs.com/files/package.json
@@ -266,7 +269,7 @@ namespace ts.JsTyping {
         if (!packageName) {
             return PackageNameValidationResult.EmptyName;
         }
-        if (packageName.length > MaxPackageNameLength) {
+        if (packageName.length > maxPackageNameLength) {
             return PackageNameValidationResult.NameTooLong;
         }
         if (packageName.charCodeAt(0) === CharacterCodes.dot) {
@@ -292,7 +295,7 @@ namespace ts.JsTyping {
             case PackageNameValidationResult.EmptyName:
                 return `Package name '${typing}' cannot be empty`;
             case PackageNameValidationResult.NameTooLong:
-                return `Package name '${typing}' should be less than ${MaxPackageNameLength} characters`;
+                return `Package name '${typing}' should be less than ${maxPackageNameLength} characters`;
             case PackageNameValidationResult.NameStartsWithDot:
                 return `Package name '${typing}' cannot start with '.'`;
             case PackageNameValidationResult.NameStartsWithUnderscore:
diff --git a/src/services/navigateTo.ts b/src/services/navigateTo.ts
index 7fa177b6a30..762726adb77 100644
--- a/src/services/navigateTo.ts
+++ b/src/services/navigateTo.ts
@@ -173,14 +173,10 @@ namespace ts.NavigateTo {
         return bestMatchKind;
     }
 
-    function compareNavigateToItems(i1: RawNavigateToItem, i2: RawNavigateToItem): number {
+    function compareNavigateToItems(i1: RawNavigateToItem, i2: RawNavigateToItem) {
         // TODO(cyrusn): get the gamut of comparisons that VS already uses here.
-        // Right now we just sort by kind first, and then by name of the item.
-        // We first sort case insensitively.  So "Aaa" will come before "bar".
-        // Then we sort case sensitively, so "aaa" will come before "Aaa".
-        return i1.matchKind - i2.matchKind ||
-            ts.compareStringsCaseInsensitive(i1.name, i2.name) ||
-            ts.compareStrings(i1.name, i2.name);
+        return compareValues(i1.matchKind, i2.matchKind)
+            || compareStringsCaseSensitiveUI(i1.name, i2.name);
     }
 
     function createNavigateToItem(rawItem: RawNavigateToItem): NavigateToItem {
diff --git a/src/services/navigationBar.ts b/src/services/navigationBar.ts
index bf34f28fed6..7d3b8e1845a 100644
--- a/src/services/navigationBar.ts
+++ b/src/services/navigationBar.ts
@@ -366,15 +366,9 @@ namespace ts.NavigationBar {
         children.sort(compareChildren);
     }
 
-    function compareChildren(child1: NavigationBarNode, child2: NavigationBarNode): number {
-        const name1 = tryGetName(child1.node), name2 = tryGetName(child2.node);
-        if (name1 && name2) {
-            const cmp = ts.compareStringsCaseInsensitive(name1, name2);
-            return cmp !== 0 ? cmp : navigationBarNodeKind(child1) - navigationBarNodeKind(child2);
-        }
-        else {
-            return name1 ? 1 : name2 ? -1 : navigationBarNodeKind(child1) - navigationBarNodeKind(child2);
-        }
+    function compareChildren(child1: NavigationBarNode, child2: NavigationBarNode) {
+        return compareStringsCaseSensitiveUI(tryGetName(child1.node), tryGetName(child2.node))
+            || compareValues(navigationBarNodeKind(child1), navigationBarNodeKind(child2));
     }
 
     /**
diff --git a/src/services/pathCompletions.ts b/src/services/pathCompletions.ts
index 780b14db719..a6dfb53da80 100644
--- a/src/services/pathCompletions.ts
+++ b/src/services/pathCompletions.ts
@@ -1,34 +1,27 @@
 /* @internal */
 namespace ts.Completions.PathCompletions {
-    export function getStringLiteralCompletionEntriesFromModuleNames(node: StringLiteral, compilerOptions: CompilerOptions, host: LanguageServiceHost, typeChecker: TypeChecker): CompletionInfo {
+    export function getStringLiteralCompletionsFromModuleNames(node: StringLiteral, compilerOptions: CompilerOptions, host: LanguageServiceHost, typeChecker: TypeChecker): CompletionEntry[] {
         const literalValue = normalizeSlashes(node.text);
 
         const scriptPath = node.getSourceFile().path;
         const scriptDirectory = getDirectoryPath(scriptPath);
 
         const span = getDirectoryFragmentTextSpan((<StringLiteral>node).text, node.getStart() + 1);
-        let entries: CompletionEntry[];
         if (isPathRelativeToScript(literalValue) || isRootedDiskPath(literalValue)) {
             const extensions = getSupportedExtensions(compilerOptions);
             if (compilerOptions.rootDirs) {
-                entries = getCompletionEntriesForDirectoryFragmentWithRootDirs(
+                return getCompletionEntriesForDirectoryFragmentWithRootDirs(
                     compilerOptions.rootDirs, literalValue, scriptDirectory, extensions, /*includeExtensions*/ false, span, compilerOptions, host, scriptPath);
             }
             else {
-                entries = getCompletionEntriesForDirectoryFragment(
+                return getCompletionEntriesForDirectoryFragment(
                     literalValue, scriptDirectory, extensions, /*includeExtensions*/ false, span, host, scriptPath);
             }
         }
         else {
             // Check for node modules
-            entries = getCompletionEntriesForNonRelativeModules(literalValue, scriptDirectory, span, compilerOptions, host, typeChecker);
+            return getCompletionEntriesForNonRelativeModules(literalValue, scriptDirectory, span, compilerOptions, host, typeChecker);
         }
-        return {
-            isGlobalCompletion: false,
-            isMemberCompletion: false,
-            isNewIdentifierLocation: true,
-            entries
-        };
     }
 
     /**
@@ -37,14 +30,17 @@ namespace ts.Completions.PathCompletions {
      */
     function getBaseDirectoriesFromRootDirs(rootDirs: string[], basePath: string, scriptPath: string, ignoreCase: boolean): string[] {
         // Make all paths absolute/normalized if they are not already
-        rootDirs = map(rootDirs, rootDirectory => normalizePath(isRootedDiskPath(rootDirectory) ? rootDirectory : combinePaths(basePath, rootDirectory)));
+        rootDirs = rootDirs.map(rootDirectory => normalizePath(isRootedDiskPath(rootDirectory) ? rootDirectory : combinePaths(basePath, rootDirectory)));
 
         // Determine the path to the directory containing the script relative to the root directory it is contained within
-        const relativeDirectory = forEach(rootDirs, rootDirectory =>
+        const relativeDirectory = firstDefined(rootDirs, rootDirectory =>
             containsPath(rootDirectory, scriptPath, basePath, ignoreCase) ? scriptPath.substr(rootDirectory.length) : undefined);
 
         // Now find a path for each potential directory that is to be merged with the one containing the script
-        return deduplicate(map(rootDirs, rootDirectory => combinePaths(rootDirectory, relativeDirectory)));
+        return deduplicate(
+            rootDirs.map(rootDirectory => combinePaths(rootDirectory, relativeDirectory)),
+            equateStringsCaseSensitive,
+            compareStringsCaseSensitive);
     }
 
     function getCompletionEntriesForDirectoryFragmentWithRootDirs(rootDirs: string[], fragment: string, scriptPath: string, extensions: ReadonlyArray<string>, includeExtensions: boolean, span: TextSpan, compilerOptions: CompilerOptions, host: LanguageServiceHost, exclude?: string): CompletionEntry[] {
@@ -144,8 +140,8 @@ namespace ts.Completions.PathCompletions {
 
         let result: CompletionEntry[];
 
+        const fileExtensions = getSupportedExtensions(compilerOptions);
         if (baseUrl) {
-            const fileExtensions = getSupportedExtensions(compilerOptions);
             const projectDir = compilerOptions.project || host.getCurrentDirectory();
             const absolute = isRootedDiskPath(baseUrl) ? baseUrl : combinePaths(projectDir, baseUrl);
             result = getCompletionEntriesForDirectoryFragment(fragment, normalizePath(absolute), fileExtensions, /*includeExtensions*/ false, span, host);
@@ -176,6 +172,15 @@ namespace ts.Completions.PathCompletions {
             result = [];
         }
 
+        if (compilerOptions.moduleResolution === ts.ModuleResolutionKind.NodeJs) {
+            forEachAncestorDirectory(scriptPath, ancestor => {
+                const nodeModules = combinePaths(ancestor, "node_modules");
+                if (host.directoryExists(nodeModules)) {
+                    getCompletionEntriesForDirectoryFragment(fragment, nodeModules, fileExtensions, /*includeExtensions*/ false, span, host, /*exclude*/ undefined, result);
+                }
+            });
+        }
+
         getCompletionEntriesFromTypings(host, compilerOptions, scriptPath, span, result);
 
         for (const moduleName of enumeratePotentialNonRelativeModules(fragment, scriptPath, compilerOptions, typeChecker, host)) {
@@ -271,64 +276,38 @@ namespace ts.Completions.PathCompletions {
             }
         }
 
-        return deduplicate(nonRelativeModuleNames);
+        return deduplicate(nonRelativeModuleNames, equateStringsCaseSensitive, compareStringsCaseSensitive);
     }
 
-    export function getTripleSlashReferenceCompletion(sourceFile: SourceFile, position: number, compilerOptions: CompilerOptions, host: LanguageServiceHost): CompletionInfo {
+    export function getTripleSlashReferenceCompletion(sourceFile: SourceFile, position: number, compilerOptions: CompilerOptions, host: LanguageServiceHost): CompletionEntry[] | undefined {
         const token = getTokenAtPosition(sourceFile, position, /*includeJsDocComment*/ false);
-        if (!token) {
-            return undefined;
-        }
-        const commentRanges: CommentRange[] = getLeadingCommentRanges(sourceFile.text, token.pos);
-
-        if (!commentRanges || !commentRanges.length) {
-            return undefined;
-        }
-
-        const range = forEach(commentRanges, commentRange => position >= commentRange.pos && position <= commentRange.end && commentRange);
-
+        const commentRanges = getLeadingCommentRanges(sourceFile.text, token.pos);
+        const range = commentRanges && find(commentRanges, commentRange => position >= commentRange.pos && position <= commentRange.end);
         if (!range) {
             return undefined;
         }
-
-        const completionInfo: CompletionInfo = {
-            /**
-             * We don't want the editor to offer any other completions, such as snippets, inside a comment.
-             */
-            isGlobalCompletion: false,
-            isMemberCompletion: false,
-            /**
-             * The user may type in a path that doesn't yet exist, creating a "new identifier"
-             * with respect to the collection of identifiers the server is aware of.
-             */
-            isNewIdentifierLocation: true,
-
-            entries: []
-        };
-
-        const text = sourceFile.text.substr(range.pos, position - range.pos);
-
+        const text = sourceFile.text.slice(range.pos, position);
         const match = tripleSlashDirectiveFragmentRegex.exec(text);
-
-        if (match) {
-            const prefix = match[1];
-            const kind = match[2];
-            const toComplete = match[3];
-
-            const scriptPath = getDirectoryPath(sourceFile.path);
-            if (kind === "path") {
-                // Give completions for a relative path
-                const span: TextSpan = getDirectoryFragmentTextSpan(toComplete, range.pos + prefix.length);
-                completionInfo.entries = getCompletionEntriesForDirectoryFragment(toComplete, scriptPath, getSupportedExtensions(compilerOptions), /*includeExtensions*/ true, span, host, sourceFile.path);
-            }
-            else {
-                // Give completions based on the typings available
-                const span: TextSpan = { start: range.pos + prefix.length, length: match[0].length - prefix.length };
-                completionInfo.entries = getCompletionEntriesFromTypings(host, compilerOptions, scriptPath, span);
-            }
+        if (!match) {
+            return undefined;
         }
 
-        return completionInfo;
+        const [, prefix, kind, toComplete] = match;
+        const scriptPath = getDirectoryPath(sourceFile.path);
+        switch (kind) {
+            case "path": {
+                // Give completions for a relative path
+                const span = getDirectoryFragmentTextSpan(toComplete, range.pos + prefix.length);
+                return getCompletionEntriesForDirectoryFragment(toComplete, scriptPath, getSupportedExtensions(compilerOptions), /*includeExtensions*/ true, span, host, sourceFile.path);
+            }
+            case "types": {
+                // Give completions based on the typings available
+                const span = createTextSpan(range.pos + prefix.length, match[0].length - prefix.length);
+                return getCompletionEntriesFromTypings(host, compilerOptions, scriptPath, span);
+            }
+            default:
+                return undefined;
+        }
     }
 
     function getCompletionEntriesFromTypings(host: LanguageServiceHost, options: CompilerOptions, scriptPath: string, span: TextSpan, result: CompletionEntry[] = []): CompletionEntry[] {
@@ -341,10 +320,9 @@ namespace ts.Completions.PathCompletions {
         else if (host.getDirectories) {
             let typeRoots: ReadonlyArray<string>;
             try {
-                // Wrap in try catch because getEffectiveTypeRoots touches the filesystem
                 typeRoots = getEffectiveTypeRoots(options, host);
             }
-            catch (e) {}
+            catch { /* Wrap in try catch because getEffectiveTypeRoots touches the filesystem */ }
 
             if (typeRoots) {
                 for (const root of typeRoots) {
@@ -376,26 +354,15 @@ namespace ts.Completions.PathCompletions {
         }
     }
 
-    function findPackageJsons(currentDir: string, host: LanguageServiceHost): string[] {
+    function findPackageJsons(directory: string, host: LanguageServiceHost): string[] {
         const paths: string[] = [];
-        let currentConfigPath: string;
-        while (true) {
-            currentConfigPath = findConfigFile(currentDir, (f) => tryFileExists(host, f), "package.json");
-            if (currentConfigPath) {
-                paths.push(currentConfigPath);
-
-                currentDir = getDirectoryPath(currentConfigPath);
-                const parent = getDirectoryPath(currentDir);
-                if (currentDir === parent) {
-                    break;
-                }
-                currentDir = parent;
+        forEachAncestorDirectory(directory, ancestor => {
+            const currentConfigPath = findConfigFile(ancestor, (f) => tryFileExists(host, f), "package.json");
+            if (!currentConfigPath) {
+                return true; // break out
             }
-            else {
-                break;
-            }
-        }
-
+            paths.push(currentConfigPath);
+        });
         return paths;
     }
 
@@ -516,7 +483,7 @@ namespace ts.Completions.PathCompletions {
         try {
             return directoryProbablyExists(path, host);
         }
-        catch (e) {}
+        catch { /*ignore*/ }
         return undefined;
     }
 
@@ -524,7 +491,7 @@ namespace ts.Completions.PathCompletions {
         try {
             return toApply && toApply.apply(host, args);
         }
-        catch (e) {}
+        catch { /*ignore*/ }
         return undefined;
     }
 }
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index 04f9d906d35..db957816146 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -515,10 +515,10 @@ namespace ts {
     }
 
     // Assumes 'value' is already lowercase.
-    function indexOfIgnoringCase(string: string, value: string): number {
-        const n = string.length - value.length;
+    function indexOfIgnoringCase(str: string, value: string): number {
+        const n = str.length - value.length;
         for (let i = 0; i <= n; i++) {
-            if (startsWithIgnoringCase(string, value, i)) {
+            if (startsWithIgnoringCase(str, value, i)) {
                 return i;
             }
         }
@@ -527,9 +527,9 @@ namespace ts {
     }
 
     // Assumes 'value' is already lowercase.
-    function startsWithIgnoringCase(string: string, value: string, start: number): boolean {
+    function startsWithIgnoringCase(str: string, value: string, start: number): boolean {
         for (let i = 0; i < value.length; i++) {
-            const ch1 = toLowerCase(string.charCodeAt(i + start));
+            const ch1 = toLowerCase(str.charCodeAt(i + start));
             const ch2 = value.charCodeAt(i);
 
             if (ch1 !== ch2) {
diff --git a/src/services/refactors/convertFunctionToEs6Class.ts b/src/services/refactors/convertFunctionToEs6Class.ts
index f5951bd26e4..b66d14ee449 100644
--- a/src/services/refactors/convertFunctionToEs6Class.ts
+++ b/src/services/refactors/convertFunctionToEs6Class.ts
@@ -50,7 +50,7 @@ namespace ts.refactor.convertFunctionToES6Class {
 
         const { file: sourceFile } = context;
         const ctorSymbol = getConstructorSymbol(context);
-        const newLine = context.rulesProvider.getFormatOptions().newLineCharacter;
+        const newLine = context.formatContext.options.newLineCharacter;
 
         const deletedNodes: Node[] = [];
         const deletes: (() => any)[] = [];
diff --git a/src/services/refactors/extractSymbol.ts b/src/services/refactors/extractSymbol.ts
index b18e12d2b96..f1a461b0088 100644
--- a/src/services/refactors/extractSymbol.ts
+++ b/src/services/refactors/extractSymbol.ts
@@ -122,28 +122,28 @@ namespace ts.refactor.extractSymbol {
             return { message, code: 0, category: DiagnosticCategory.Message, key: message };
         }
 
-        export const CannotExtractRange: DiagnosticMessage = createMessage("Cannot extract range.");
-        export const CannotExtractImport: DiagnosticMessage = createMessage("Cannot extract import statement.");
-        export const CannotExtractSuper: DiagnosticMessage = createMessage("Cannot extract super call.");
-        export const CannotExtractEmpty: DiagnosticMessage = createMessage("Cannot extract empty range.");
-        export const ExpressionExpected: DiagnosticMessage = createMessage("expression expected.");
-        export const UselessConstantType: DiagnosticMessage = createMessage("No reason to extract constant of type.");
-        export const StatementOrExpressionExpected: DiagnosticMessage = createMessage("Statement or expression expected.");
-        export const CannotExtractRangeContainingConditionalBreakOrContinueStatements: DiagnosticMessage = createMessage("Cannot extract range containing conditional break or continue statements.");
-        export const CannotExtractRangeContainingConditionalReturnStatement: DiagnosticMessage = createMessage("Cannot extract range containing conditional return statement.");
-        export const CannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange: DiagnosticMessage = createMessage("Cannot extract range containing labeled break or continue with target outside of the range.");
-        export const CannotExtractRangeThatContainsWritesToReferencesLocatedOutsideOfTheTargetRangeInGenerators: DiagnosticMessage = createMessage("Cannot extract range containing writes to references located outside of the target range in generators.");
-        export const TypeWillNotBeVisibleInTheNewScope = createMessage("Type will not visible in the new scope.");
-        export const FunctionWillNotBeVisibleInTheNewScope = createMessage("Function will not visible in the new scope.");
-        export const CannotExtractIdentifier = createMessage("Select more than a single identifier.");
-        export const CannotExtractExportedEntity = createMessage("Cannot extract exported declaration");
-        export const CannotWriteInExpression = createMessage("Cannot write back side-effects when extracting an expression");
-        export const CannotExtractReadonlyPropertyInitializerOutsideConstructor = createMessage("Cannot move initialization of read-only class property outside of the constructor");
-        export const CannotExtractAmbientBlock = createMessage("Cannot extract code from ambient contexts");
-        export const CannotAccessVariablesFromNestedScopes = createMessage("Cannot access variables from nested scopes");
-        export const CannotExtractToOtherFunctionLike = createMessage("Cannot extract method to a function-like scope that is not a function");
-        export const CannotExtractToJSClass = createMessage("Cannot extract constant to a class scope in JS");
-        export const CannotExtractToExpressionArrowFunction = createMessage("Cannot extract constant to an arrow function without a block");
+        export const cannotExtractRange: DiagnosticMessage = createMessage("Cannot extract range.");
+        export const cannotExtractImport: DiagnosticMessage = createMessage("Cannot extract import statement.");
+        export const cannotExtractSuper: DiagnosticMessage = createMessage("Cannot extract super call.");
+        export const cannotExtractEmpty: DiagnosticMessage = createMessage("Cannot extract empty range.");
+        export const expressionExpected: DiagnosticMessage = createMessage("expression expected.");
+        export const uselessConstantType: DiagnosticMessage = createMessage("No reason to extract constant of type.");
+        export const statementOrExpressionExpected: DiagnosticMessage = createMessage("Statement or expression expected.");
+        export const cannotExtractRangeContainingConditionalBreakOrContinueStatements: DiagnosticMessage = createMessage("Cannot extract range containing conditional break or continue statements.");
+        export const cannotExtractRangeContainingConditionalReturnStatement: DiagnosticMessage = createMessage("Cannot extract range containing conditional return statement.");
+        export const cannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange: DiagnosticMessage = createMessage("Cannot extract range containing labeled break or continue with target outside of the range.");
+        export const cannotExtractRangeThatContainsWritesToReferencesLocatedOutsideOfTheTargetRangeInGenerators: DiagnosticMessage = createMessage("Cannot extract range containing writes to references located outside of the target range in generators.");
+        export const typeWillNotBeVisibleInTheNewScope = createMessage("Type will not visible in the new scope.");
+        export const functionWillNotBeVisibleInTheNewScope = createMessage("Function will not visible in the new scope.");
+        export const cannotExtractIdentifier = createMessage("Select more than a single identifier.");
+        export const cannotExtractExportedEntity = createMessage("Cannot extract exported declaration");
+        export const cannotWriteInExpression = createMessage("Cannot write back side-effects when extracting an expression");
+        export const cannotExtractReadonlyPropertyInitializerOutsideConstructor = createMessage("Cannot move initialization of read-only class property outside of the constructor");
+        export const cannotExtractAmbientBlock = createMessage("Cannot extract code from ambient contexts");
+        export const cannotAccessVariablesFromNestedScopes = createMessage("Cannot access variables from nested scopes");
+        export const cannotExtractToOtherFunctionLike = createMessage("Cannot extract method to a function-like scope that is not a function");
+        export const cannotExtractToJSClass = createMessage("Cannot extract constant to a class scope in JS");
+        export const cannotExtractToExpressionArrowFunction = createMessage("Cannot extract constant to an arrow function without a block");
     }
 
     enum RangeFacts {
@@ -198,7 +198,7 @@ namespace ts.refactor.extractSymbol {
         const { length } = span;
 
         if (length === 0) {
-            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.CannotExtractEmpty)] };
+            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractEmpty)] };
         }
 
         // Walk up starting from the the start position until we find a non-SourceFile node that subsumes the selected span.
@@ -215,18 +215,18 @@ namespace ts.refactor.extractSymbol {
 
         if (!start || !end) {
             // cannot find either start or end node
-            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.CannotExtractRange)] };
+            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractRange)] };
         }
 
         if (start.parent !== end.parent) {
             // start and end nodes belong to different subtrees
-            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.CannotExtractRange)] };
+            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractRange)] };
         }
 
         if (start !== end) {
             // start and end should be statements and parent should be either block or a source file
             if (!isBlockLike(start.parent)) {
-                return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.CannotExtractRange)] };
+                return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractRange)] };
             }
             const statements: Statement[] = [];
             for (const statement of (<BlockLike>start.parent).statements) {
@@ -246,7 +246,7 @@ namespace ts.refactor.extractSymbol {
 
         if (isReturnStatement(start) && !start.expression) {
             // Makes no sense to extract an expression-less return statement.
-            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.CannotExtractRange)] };
+            return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractRange)] };
         }
 
         // We have a single node (start)
@@ -293,7 +293,7 @@ namespace ts.refactor.extractSymbol {
 
         function checkRootNode(node: Node): Diagnostic[] | undefined {
             if (isIdentifier(isExpressionStatement(node) ? node.expression : node)) {
-                return [createDiagnosticForNode(node, Messages.CannotExtractIdentifier)];
+                return [createDiagnosticForNode(node, Messages.cannotExtractIdentifier)];
             }
             return undefined;
         }
@@ -331,12 +331,12 @@ namespace ts.refactor.extractSymbol {
                 Continue = 1 << 1,
                 Return = 1 << 2
             }
-            if (!isStatement(nodeToCheck) && !(isPartOfExpression(nodeToCheck) && isExtractableExpression(nodeToCheck))) {
-                return [createDiagnosticForNode(nodeToCheck, Messages.StatementOrExpressionExpected)];
+            if (!isStatement(nodeToCheck) && !(isExpressionNode(nodeToCheck) && isExtractableExpression(nodeToCheck))) {
+                return [createDiagnosticForNode(nodeToCheck, Messages.statementOrExpressionExpected)];
             }
 
-            if (isInAmbientContext(nodeToCheck)) {
-                return [createDiagnosticForNode(nodeToCheck, Messages.CannotExtractAmbientBlock)];
+            if (nodeToCheck.flags & NodeFlags.Ambient) {
+                return [createDiagnosticForNode(nodeToCheck, Messages.cannotExtractAmbientBlock)];
             }
 
             // If we're in a class, see whether we're in a static region (static property initializer, static method, class constructor parameter default)
@@ -362,7 +362,7 @@ namespace ts.refactor.extractSymbol {
                 if (isDeclaration(node)) {
                     const declaringNode = (node.kind === SyntaxKind.VariableDeclaration) ? node.parent.parent : node;
                     if (hasModifier(declaringNode, ModifierFlags.Export)) {
-                        (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractExportedEntity));
+                        (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractExportedEntity));
                         return true;
                     }
                     declarations.push(node.symbol);
@@ -371,7 +371,7 @@ namespace ts.refactor.extractSymbol {
                 // Some things can't be extracted in certain situations
                 switch (node.kind) {
                     case SyntaxKind.ImportDeclaration:
-                        (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractImport));
+                        (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractImport));
                         return true;
                     case SyntaxKind.SuperKeyword:
                         // For a super *constructor call*, we have to be extracting the entire class,
@@ -380,7 +380,7 @@ namespace ts.refactor.extractSymbol {
                             // Super constructor call
                             const containingClass = getContainingClass(node);
                             if (containingClass.pos < span.start || containingClass.end >= (span.start + span.length)) {
-                                (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractSuper));
+                                (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractSuper));
                                 return true;
                             }
                         }
@@ -396,7 +396,7 @@ namespace ts.refactor.extractSymbol {
                         case SyntaxKind.ClassDeclaration:
                             if (node.parent.kind === SyntaxKind.SourceFile && (node.parent as ts.SourceFile).externalModuleIndicator === undefined) {
                                 // You cannot extract global declarations
-                                (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.FunctionWillNotBeVisibleInTheNewScope));
+                                (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.functionWillNotBeVisibleInTheNewScope));
                             }
                             break;
                     }
@@ -452,13 +452,13 @@ namespace ts.refactor.extractSymbol {
                             if (label) {
                                 if (!contains(seenLabels, label.escapedText)) {
                                     // attempts to jump to label that is not in range to be extracted
-                                    (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange));
+                                    (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractRangeContainingLabeledBreakOrContinueStatementWithTargetOutsideOfTheRange));
                                 }
                             }
                             else {
                                 if (!(permittedJumps & (node.kind === SyntaxKind.BreakStatement ? PermittedJumps.Break : PermittedJumps.Continue))) {
                                     // attempt to break or continue in a forbidden context
-                                    (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractRangeContainingConditionalBreakOrContinueStatements));
+                                    (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractRangeContainingConditionalBreakOrContinueStatements));
                                 }
                             }
                             break;
@@ -474,7 +474,7 @@ namespace ts.refactor.extractSymbol {
                             rangeFacts |= RangeFacts.HasReturn;
                         }
                         else {
-                            (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.CannotExtractRangeContainingConditionalReturnStatement));
+                            (errors || (errors = [])).push(createDiagnosticForNode(node, Messages.cannotExtractRangeContainingConditionalReturnStatement));
                         }
                         break;
                     default:
@@ -491,7 +491,7 @@ namespace ts.refactor.extractSymbol {
         if (isStatement(node)) {
             return [node];
         }
-        else if (isPartOfExpression(node)) {
+        else if (isExpressionNode(node)) {
             // If our selection is the expression in an ExpressionStatement, expand
             // the selection to include the enclosing Statement (this stops us
             // from trying to care about the return value of the extracted function
@@ -730,7 +730,7 @@ namespace ts.refactor.extractSymbol {
                 let type = checker.getTypeOfSymbolAtLocation(usage.symbol, usage.node);
                 // Widen the type so we don't emit nonsense annotations like "function fn(x: 3) {"
                 type = checker.getBaseTypeOfLiteralType(type);
-                typeNode = checker.typeToTypeNode(type, node, NodeBuilderFlags.NoTruncation);
+                typeNode = checker.typeToTypeNode(type, scope, NodeBuilderFlags.NoTruncation);
             }
 
             const paramDecl = createParameter(
@@ -1177,30 +1177,11 @@ namespace ts.refactor.extractSymbol {
         {type: type1, declaration: declaration1}: {type: Type, declaration?: Declaration},
         {type: type2, declaration: declaration2}: {type: Type, declaration?: Declaration}) {
 
-        if (declaration1) {
-            if (declaration2) {
-                const positionDiff = declaration1.pos - declaration2.pos;
-                if (positionDiff !== 0) {
-                    return positionDiff;
-                }
-            }
-            else {
-                return 1; // Sort undeclared type parameters to the front.
-            }
-        }
-        else if (declaration2) {
-            return -1; // Sort undeclared type parameters to the front.
-        }
-
-        const name1 = type1.symbol ? type1.symbol.getName() : "";
-        const name2 = type2.symbol ? type2.symbol.getName() : "";
-        const nameDiff = compareStrings(name1, name2);
-        if (nameDiff !== 0) {
-            return nameDiff;
-        }
-
-        // IDs are guaranteed to be unique, so this ensures a total ordering.
-        return type1.id - type2.id;
+        return compareProperties(declaration1, declaration2, "pos", compareValues)
+            || compareStringsCaseSensitive(
+                type1.symbol ? type1.symbol.getName() : "",
+                type2.symbol ? type2.symbol.getName() : "")
+            || compareValues(type1.id, type2.id);
     }
 
     function getCalledExpression(scope: Node, range: TargetRange, functionNameText: string): Expression {
@@ -1455,10 +1436,10 @@ namespace ts.refactor.extractSymbol {
             const statements = targetRange.range as ReadonlyArray<Statement>;
             const start = first(statements).getStart();
             const end = last(statements).end;
-            expressionDiagnostic = createFileDiagnostic(sourceFile, start, end - start, Messages.ExpressionExpected);
+            expressionDiagnostic = createFileDiagnostic(sourceFile, start, end - start, Messages.expressionExpected);
         }
         else if (checker.getTypeAtLocation(expression).flags & (TypeFlags.Void | TypeFlags.Never)) {
-            expressionDiagnostic = createDiagnosticForNode(expression, Messages.UselessConstantType);
+            expressionDiagnostic = createDiagnosticForNode(expression, Messages.uselessConstantType);
         }
 
         // initialize results
@@ -1468,7 +1449,7 @@ namespace ts.refactor.extractSymbol {
 
             functionErrorsPerScope.push(
                 isFunctionLikeDeclaration(scope) && scope.kind !== SyntaxKind.FunctionDeclaration
-                    ? [createDiagnosticForNode(scope, Messages.CannotExtractToOtherFunctionLike)]
+                    ? [createDiagnosticForNode(scope, Messages.cannotExtractToOtherFunctionLike)]
                     : []);
 
             const constantErrors = [];
@@ -1476,11 +1457,11 @@ namespace ts.refactor.extractSymbol {
                 constantErrors.push(expressionDiagnostic);
             }
             if (isClassLike(scope) && isInJavaScriptFile(scope)) {
-                constantErrors.push(createDiagnosticForNode(scope, Messages.CannotExtractToJSClass));
+                constantErrors.push(createDiagnosticForNode(scope, Messages.cannotExtractToJSClass));
             }
             if (isArrowFunction(scope) && !isBlock(scope.body)) {
                 // TODO (https://github.com/Microsoft/TypeScript/issues/18924): allow this
-                constantErrors.push(createDiagnosticForNode(scope, Messages.CannotExtractToExpressionArrowFunction));
+                constantErrors.push(createDiagnosticForNode(scope, Messages.cannotExtractToExpressionArrowFunction));
             }
             constantErrorsPerScope.push(constantErrors);
         }
@@ -1548,7 +1529,7 @@ namespace ts.refactor.extractSymbol {
             // local will actually be declared at the same level as the extracted expression).
             if (i > 0 && (scopeUsages.usages.size > 0 || scopeUsages.typeParameterUsages.size > 0)) {
                 const errorNode = isReadonlyArray(targetRange.range) ? targetRange.range[0] : targetRange.range;
-                constantErrorsPerScope[i].push(createDiagnosticForNode(errorNode, Messages.CannotAccessVariablesFromNestedScopes));
+                constantErrorsPerScope[i].push(createDiagnosticForNode(errorNode, Messages.cannotAccessVariablesFromNestedScopes));
             }
 
             let hasWrite = false;
@@ -1568,17 +1549,17 @@ namespace ts.refactor.extractSymbol {
             Debug.assert(isReadonlyArray(targetRange.range) || exposedVariableDeclarations.length === 0);
 
             if (hasWrite && !isReadonlyArray(targetRange.range)) {
-                const diag = createDiagnosticForNode(targetRange.range, Messages.CannotWriteInExpression);
+                const diag = createDiagnosticForNode(targetRange.range, Messages.cannotWriteInExpression);
                 functionErrorsPerScope[i].push(diag);
                 constantErrorsPerScope[i].push(diag);
             }
             else if (readonlyClassPropertyWrite && i > 0) {
-                const diag = createDiagnosticForNode(readonlyClassPropertyWrite, Messages.CannotExtractReadonlyPropertyInitializerOutsideConstructor);
+                const diag = createDiagnosticForNode(readonlyClassPropertyWrite, Messages.cannotExtractReadonlyPropertyInitializerOutsideConstructor);
                 functionErrorsPerScope[i].push(diag);
                 constantErrorsPerScope[i].push(diag);
             }
             else if (firstExposedNonVariableDeclaration) {
-                const diag = createDiagnosticForNode(firstExposedNonVariableDeclaration, Messages.CannotExtractExportedEntity);
+                const diag = createDiagnosticForNode(firstExposedNonVariableDeclaration, Messages.cannotExtractExportedEntity);
                 functionErrorsPerScope[i].push(diag);
                 constantErrorsPerScope[i].push(diag);
             }
@@ -1710,7 +1691,7 @@ namespace ts.refactor.extractSymbol {
             if (targetRange.facts & RangeFacts.IsGenerator && usage === Usage.Write) {
                 // this is write to a reference located outside of the target scope and range is extracted into generator
                 // currently this is unsupported scenario
-                const diag = createDiagnosticForNode(identifier, Messages.CannotExtractRangeThatContainsWritesToReferencesLocatedOutsideOfTheTargetRangeInGenerators);
+                const diag = createDiagnosticForNode(identifier, Messages.cannotExtractRangeThatContainsWritesToReferencesLocatedOutsideOfTheTargetRangeInGenerators);
                 for (const errors of functionErrorsPerScope) {
                     errors.push(diag);
                 }
@@ -1733,7 +1714,7 @@ namespace ts.refactor.extractSymbol {
                         // If the symbol is a type parameter that won't be in scope, we'll pass it as a type argument
                         // so there's no problem.
                         if (!(symbol.flags & SymbolFlags.TypeParameter)) {
-                            const diag = createDiagnosticForNode(identifier, Messages.TypeWillNotBeVisibleInTheNewScope);
+                            const diag = createDiagnosticForNode(identifier, Messages.typeWillNotBeVisibleInTheNewScope);
                             functionErrorsPerScope[i].push(diag);
                             constantErrorsPerScope[i].push(diag);
                         }
diff --git a/src/services/refactors/installTypesForPackage.ts b/src/services/refactors/installTypesForPackage.ts
index 5edc5570710..996645fc15d 100644
--- a/src/services/refactors/installTypesForPackage.ts
+++ b/src/services/refactors/installTypesForPackage.ts
@@ -12,8 +12,7 @@ namespace ts.refactor.installTypesForPackage {
     registerRefactor(installTypesForPackage);
 
     function getAvailableActions(context: RefactorContext): ApplicableRefactorInfo[] | undefined {
-        const options = context.program.getCompilerOptions();
-        if (options.noImplicitAny || options.strict) {
+        if (getStrictOptionValue(context.program.getCompilerOptions(), "noImplicitAny")) {
             // Then it will be available via `fixCannotFindModule`.
             return undefined;
         }
diff --git a/src/services/refactors/refactors.ts b/src/services/refactors/refactors.ts
index f4b56422a89..3858b198743 100644
--- a/src/services/refactors/refactors.ts
+++ b/src/services/refactors/refactors.ts
@@ -2,3 +2,4 @@
 /// <reference path="convertFunctionToEs6Class.ts" />
 /// <reference path="extractSymbol.ts" />
 /// <reference path="installTypesForPackage.ts" />
+/// <reference path="useDefaultImport.ts" />
diff --git a/src/services/refactors/useDefaultImport.ts b/src/services/refactors/useDefaultImport.ts
new file mode 100644
index 00000000000..56faf082a49
--- /dev/null
+++ b/src/services/refactors/useDefaultImport.ts
@@ -0,0 +1,96 @@
+/* @internal */
+namespace ts.refactor.installTypesForPackage {
+    const actionName = "Convert to default import";
+
+    const useDefaultImport: Refactor = {
+        name: actionName,
+        description: getLocaleSpecificMessage(Diagnostics.Convert_to_default_import),
+        getEditsForAction,
+        getAvailableActions,
+    };
+
+    registerRefactor(useDefaultImport);
+
+    function getAvailableActions(context: RefactorContext): ApplicableRefactorInfo[] | undefined {
+        const { file, startPosition, program } = context;
+
+        if (!program.getCompilerOptions().allowSyntheticDefaultImports) {
+            return undefined;
+        }
+
+        const importInfo = getConvertibleImportAtPosition(file, startPosition);
+        if (!importInfo) {
+            return undefined;
+        }
+
+        const module = ts.getResolvedModule(file, importInfo.moduleSpecifier.text);
+        const resolvedFile = program.getSourceFile(module.resolvedFileName);
+        if (!(resolvedFile.externalModuleIndicator && isExportAssignment(resolvedFile.externalModuleIndicator) && resolvedFile.externalModuleIndicator.isExportEquals)) {
+            return undefined;
+        }
+
+        return [
+            {
+                name: useDefaultImport.name,
+                description: useDefaultImport.description,
+                actions: [
+                    {
+                        description: useDefaultImport.description,
+                        name: actionName,
+                    },
+                ],
+            },
+        ];
+    }
+
+    function getEditsForAction(context: RefactorContext, _actionName: string): RefactorEditInfo | undefined {
+        const { file, startPosition } = context;
+        Debug.assertEqual(actionName, _actionName);
+        const importInfo = getConvertibleImportAtPosition(file, startPosition);
+        if (!importInfo) {
+            return undefined;
+        }
+        const { importStatement, name, moduleSpecifier } = importInfo;
+        const newImportClause = createImportClause(name, /*namedBindings*/ undefined);
+        const newImportStatement = ts.createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, newImportClause, moduleSpecifier);
+        return {
+            edits: textChanges.ChangeTracker.with(context, t => t.replaceNode(file, importStatement, newImportStatement)),
+            renameFilename: undefined,
+            renameLocation: undefined,
+        };
+    }
+
+    function getConvertibleImportAtPosition(
+        file: SourceFile,
+        startPosition: number,
+    ): { importStatement: AnyImportSyntax, name: Identifier, moduleSpecifier: StringLiteral } | undefined {
+        let node = getTokenAtPosition(file, startPosition, /*includeJsDocComment*/ false);
+        while (true) {
+            switch (node.kind) {
+                case SyntaxKind.ImportEqualsDeclaration:
+                    const eq = node as ImportEqualsDeclaration;
+                    const { moduleReference } = eq;
+                    return moduleReference.kind === SyntaxKind.ExternalModuleReference && isStringLiteral(moduleReference.expression)
+                        ? { importStatement: eq, name: eq.name, moduleSpecifier: moduleReference.expression }
+                        : undefined;
+                case SyntaxKind.ImportDeclaration:
+                    const d = node as ImportDeclaration;
+                    const { importClause } = d;
+                    return !importClause.name && importClause.namedBindings.kind === SyntaxKind.NamespaceImport && isStringLiteral(d.moduleSpecifier)
+                        ? { importStatement: d, name: importClause.namedBindings.name, moduleSpecifier: d.moduleSpecifier }
+                        : undefined;
+                // For known child node kinds of convertible imports, try again with parent node.
+                case SyntaxKind.NamespaceImport:
+                case SyntaxKind.ExternalModuleReference:
+                case SyntaxKind.ImportKeyword:
+                case SyntaxKind.Identifier:
+                case SyntaxKind.StringLiteral:
+                case SyntaxKind.AsteriskToken:
+                    break;
+                default:
+                    return undefined;
+            }
+            node = node.parent;
+        }
+    }
+}
diff --git a/src/services/services.ts b/src/services/services.ts
index d6e75868852..37298c8eba8 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -31,16 +31,14 @@
 
 namespace ts {
     /** The version of the language service API */
-    export const servicesVersion = "0.5";
-
-    /* @internal */
-    let ruleProvider: formatting.RulesProvider;
+    export const servicesVersion = "0.7";
 
     function createNode<TKind extends SyntaxKind>(kind: TKind, pos: number, end: number, parent?: Node): NodeObject | TokenObject<TKind> | IdentifierObject {
         const node = isNodeKind(kind) ? new NodeObject(kind, pos, end) :
             kind === SyntaxKind.Identifier ? new IdentifierObject(SyntaxKind.Identifier, pos, end) :
                 new TokenObject(kind, pos, end);
         node.parent = parent;
+        node.flags = parent.flags & NodeFlags.ContextFlags;
         return node;
     }
 
@@ -276,7 +274,10 @@ namespace ts {
         }
 
         public getText(sourceFile?: SourceFile): string {
-            return (sourceFile || this.getSourceFile()).text.substring(this.getStart(), this.getEnd());
+            if (!sourceFile) {
+                sourceFile = this.getSourceFile();
+            }
+            return sourceFile.text.substring(this.getStart(sourceFile), this.getEnd());
         }
 
         public getChildCount(): number {
@@ -342,9 +343,29 @@ namespace ts {
             return this.declarations;
         }
 
-        getDocumentationComment(): SymbolDisplayPart[] {
+        getDocumentationComment(checker: TypeChecker | undefined): SymbolDisplayPart[] {
             if (this.documentationComment === undefined) {
-                this.documentationComment = JsDoc.getJsDocCommentsFromDeclarations(this.declarations);
+                if (this.declarations) {
+                    this.documentationComment = JsDoc.getJsDocCommentsFromDeclarations(this.declarations);
+
+                    if (this.documentationComment.length === 0 || this.declarations.some(hasJSDocInheritDocTag)) {
+                        if (checker) {
+                            for (const declaration of this.declarations) {
+                                const inheritedDocs = findInheritedJSDocComments(declaration, this.getName(), checker);
+                                if (inheritedDocs.length > 0) {
+                                    if (this.documentationComment.length > 0) {
+                                        inheritedDocs.push(ts.lineBreakPart());
+                                    }
+                                    this.documentationComment = concatenate(inheritedDocs, this.documentationComment);
+                                    break;
+                                }
+                            }
+                        }
+                    }
+                }
+                else {
+                    this.documentationComment = [];
+                }
             }
 
             return this.documentationComment;
@@ -473,7 +494,23 @@ namespace ts {
 
         getDocumentationComment(): SymbolDisplayPart[] {
             if (this.documentationComment === undefined) {
-                this.documentationComment = this.declaration ? JsDoc.getJsDocCommentsFromDeclarations([this.declaration]) : [];
+                if (this.declaration) {
+                    this.documentationComment = JsDoc.getJsDocCommentsFromDeclarations([this.declaration]);
+
+                    if (this.documentationComment.length === 0 || hasJSDocInheritDocTag(this.declaration)) {
+                        const inheritedDocs = findInheritedJSDocComments(this.declaration, this.declaration.symbol.getName(), this.checker);
+                        if (this.documentationComment.length > 0) {
+                            inheritedDocs.push(ts.lineBreakPart());
+                        }
+                        this.documentationComment = concatenate(
+                            inheritedDocs,
+                            this.documentationComment
+                        );
+                    }
+                }
+                else {
+                    this.documentationComment = [];
+                }
             }
 
             return this.documentationComment;
@@ -488,6 +525,58 @@ namespace ts {
         }
     }
 
+    /**
+     * Returns whether or not the given node has a JSDoc "inheritDoc" tag on it.
+     * @param node the Node in question.
+     * @returns `true` if `node` has a JSDoc "inheritDoc" tag on it, otherwise `false`.
+     */
+    function hasJSDocInheritDocTag(node: Node) {
+        return ts.getJSDocTags(node).some(tag => tag.tagName.text === "inheritDoc");
+    }
+
+    /**
+     * Attempts to find JSDoc comments for possibly-inherited properties.  Checks superclasses then traverses
+     * implemented interfaces until a symbol is found with the same name and with documentation.
+     * @param declaration The possibly-inherited declaration to find comments for.
+     * @param propertyName The name of the possibly-inherited property.
+     * @param typeChecker A TypeChecker, used to find inherited properties.
+     * @returns A filled array of documentation comments if any were found, otherwise an empty array.
+     */
+    function findInheritedJSDocComments(declaration: Declaration, propertyName: string, typeChecker: TypeChecker): SymbolDisplayPart[] {
+        let foundDocs = false;
+        return flatMap(getAllSuperTypeNodes(declaration), superTypeNode => {
+            if (foundDocs) {
+                return emptyArray;
+            }
+            const superType = typeChecker.getTypeAtLocation(superTypeNode);
+            if (!superType) {
+                return emptyArray;
+            }
+            const baseProperty = typeChecker.getPropertyOfType(superType, propertyName);
+            if (!baseProperty) {
+                return emptyArray;
+            }
+            const inheritedDocs = baseProperty.getDocumentationComment(typeChecker);
+            foundDocs = inheritedDocs.length > 0;
+            return inheritedDocs;
+        });
+    }
+
+    /**
+     * Finds and returns the `TypeNode` for all super classes and implemented interfaces given a declaration.
+     * @param declaration The possibly-inherited declaration.
+     * @returns A filled array of `TypeNode`s containing all super classes and implemented interfaces if any exist, otherwise an empty array.
+     */
+    function getAllSuperTypeNodes(declaration: Declaration): ReadonlyArray<TypeNode> {
+        const container = declaration.parent;
+        if (!container || (!isClassDeclaration(container) && !isInterfaceDeclaration(container))) {
+            return emptyArray;
+        }
+        const extended = getClassExtendsHeritageClauseElement(container);
+        const types = extended ? [extended] : emptyArray;
+        return isClassLike(container) ? concatenate(types, getClassImplementsHeritageClauseElements(container)) : types;
+    }
+
     class SourceFileObject extends NodeObject implements SourceFile {
         public kind: SyntaxKind.SourceFile;
         public _declarationBrand: any;
@@ -724,9 +813,9 @@ namespace ts {
 
                     case SyntaxKind.BinaryExpression:
                         if (getSpecialPropertyAssignmentKind(node as BinaryExpression) !== SpecialPropertyAssignmentKind.None) {
-                           addDeclaration(node as BinaryExpression);
+                            addDeclaration(node as BinaryExpression);
                         }
-                        // falls through
+                    // falls through
 
                     default:
                         forEachChild(node, visit);
@@ -1065,7 +1154,6 @@ namespace ts {
         documentRegistry: DocumentRegistry = createDocumentRegistry(host.useCaseSensitiveFileNames && host.useCaseSensitiveFileNames(), host.getCurrentDirectory())): LanguageService {
 
         const syntaxTreeCache: SyntaxTreeCache = new SyntaxTreeCache(host);
-        ruleProvider = ruleProvider || new formatting.RulesProvider();
         let program: Program;
         let lastProjectVersion: string;
         let lastTypesRootVersion = 0;
@@ -1095,11 +1183,6 @@ namespace ts {
             return sourceFile;
         }
 
-        function getRuleProvider(options: FormatCodeSettings) {
-            ruleProvider.ensureUpToDate(options);
-            return ruleProvider;
-        }
-
         function synchronizeHostData(): void {
             // perform fast check if host supports it
             if (host.getProjectVersion) {
@@ -1322,14 +1405,21 @@ namespace ts {
             return [...program.getOptionsDiagnostics(cancellationToken), ...program.getGlobalDiagnostics(cancellationToken)];
         }
 
-        function getCompletionsAtPosition(fileName: string, position: number): CompletionInfo {
+        function getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions = { includeExternalModuleExports: false }): CompletionInfo {
             synchronizeHostData();
-            return Completions.getCompletionsAtPosition(host, program.getTypeChecker(), log, program.getCompilerOptions(), getValidSourceFile(fileName), position, program.getSourceFiles());
+            return Completions.getCompletionsAtPosition(
+                host,
+                program.getTypeChecker(),
+                log,
+                program.getCompilerOptions(),
+                getValidSourceFile(fileName),
+                position,
+                program.getSourceFiles(),
+                options);
         }
 
         function getCompletionEntryDetails(fileName: string, position: number, name: string, formattingOptions?: FormatCodeSettings, source?: string): CompletionEntryDetails {
             synchronizeHostData();
-            const ruleProvider = formattingOptions ? getRuleProvider(formattingOptions) : undefined;
             return Completions.getCompletionEntryDetails(
                 program.getTypeChecker(),
                 log,
@@ -1339,7 +1429,7 @@ namespace ts {
                 { name, source },
                 program.getSourceFiles(),
                 host,
-                ruleProvider);
+                formattingOptions && formatting.getFormatContext(formattingOptions));
         }
 
         function getCompletionEntrySymbol(fileName: string, position: number, name: string, source?: string): Symbol {
@@ -1387,7 +1477,7 @@ namespace ts {
                                 kindModifiers: ScriptElementKindModifier.none,
                                 textSpan: createTextSpan(node.getStart(), node.getWidth()),
                                 displayParts: typeToDisplayParts(typeChecker, type, getContainerNode(node)),
-                                documentation: type.symbol ? type.symbol.getDocumentationComment() : undefined,
+                                documentation: type.symbol ? type.symbol.getDocumentationComment(typeChecker) : undefined,
                                 tags: type.symbol ? type.symbol.getJsDocTags() : undefined
                             };
                         }
@@ -1428,6 +1518,11 @@ namespace ts {
             return GoToDefinition.getDefinitionAtPosition(program, getValidSourceFile(fileName), position);
         }
 
+        function getDefinitionAndBoundSpan(fileName: string, position: number): DefinitionInfoAndBoundSpan {
+            synchronizeHostData();
+            return GoToDefinition.getDefinitionAndBoundSpan(program, getValidSourceFile(fileName), position);
+        }
+
         function getTypeDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[] {
             synchronizeHostData();
             return GoToDefinition.getTypeDefinitionAtPosition(program.getTypeChecker(), getValidSourceFile(fileName), position);
@@ -1733,32 +1828,27 @@ namespace ts {
 
         function getFormattingEditsForRange(fileName: string, start: number, end: number, options: FormatCodeOptions | FormatCodeSettings): TextChange[] {
             const sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
-            const settings = toEditorSettings(options);
-            return formatting.formatSelection(start, end, sourceFile, getRuleProvider(settings), settings);
+            return formatting.formatSelection(start, end, sourceFile, formatting.getFormatContext(toEditorSettings(options)));
         }
 
         function getFormattingEditsForDocument(fileName: string, options: FormatCodeOptions | FormatCodeSettings): TextChange[] {
-            const sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
-            const settings = toEditorSettings(options);
-            return formatting.formatDocument(sourceFile, getRuleProvider(settings), settings);
+            return formatting.formatDocument(syntaxTreeCache.getCurrentSourceFile(fileName), formatting.getFormatContext(toEditorSettings(options)));
         }
 
         function getFormattingEditsAfterKeystroke(fileName: string, position: number, key: string, options: FormatCodeOptions | FormatCodeSettings): TextChange[] {
             const sourceFile = syntaxTreeCache.getCurrentSourceFile(fileName);
-            const settings = toEditorSettings(options);
+            const formatContext = formatting.getFormatContext(toEditorSettings(options));
 
             if (!isInComment(sourceFile, position)) {
-                if (key === "{") {
-                    return formatting.formatOnOpeningCurly(position, sourceFile, getRuleProvider(settings), settings);
-                }
-                else if (key === "}") {
-                    return formatting.formatOnClosingCurly(position, sourceFile, getRuleProvider(settings), settings);
-                }
-                else if (key === ";") {
-                    return formatting.formatOnSemicolon(position, sourceFile, getRuleProvider(settings), settings);
-                }
-                else if (key === "\n") {
-                    return formatting.formatOnEnter(position, sourceFile, getRuleProvider(settings), settings);
+                switch (key) {
+                    case "{":
+                        return formatting.formatOnOpeningCurly(position, sourceFile, formatContext);
+                    case "}":
+                        return formatting.formatOnClosingCurly(position, sourceFile, formatContext);
+                    case ";":
+                        return formatting.formatOnSemicolon(position, sourceFile, formatContext);
+                    case "\n":
+                        return formatting.formatOnEnter(position, sourceFile, formatContext);
                 }
             }
 
@@ -1770,11 +1860,11 @@ namespace ts {
             const sourceFile = getValidSourceFile(fileName);
             const span = createTextSpanFromBounds(start, end);
             const newLineCharacter = getNewLineOrDefaultFromHost(host);
-            const rulesProvider = getRuleProvider(formatOptions);
+            const formatContext = formatting.getFormatContext(formatOptions);
 
-            return flatMap(deduplicate(errorCodes), errorCode => {
+            return flatMap(deduplicate(errorCodes, equateValues, compareValues), errorCode => {
                 cancellationToken.throwIfCancellationRequested();
-                return codefix.getFixes({ errorCode, sourceFile, span, program, newLineCharacter, host, cancellationToken, rulesProvider });
+                return codefix.getFixes({ errorCode, sourceFile, span, program, newLineCharacter, host, cancellationToken, formatContext });
             });
         }
 
@@ -1791,7 +1881,7 @@ namespace ts {
             }
         }
 
-        function getDocCommentTemplateAtPosition(fileName: string, position: number): TextInsertion {
+        function getDocCommentTemplateAtPosition(fileName: string, position: number): TextInsertion | undefined {
             return JsDoc.getDocCommentTemplateAtPosition(getNewLineOrDefaultFromHost(host), syntaxTreeCache.getCurrentSourceFile(fileName), position);
         }
 
@@ -1980,9 +2070,7 @@ namespace ts {
             }
 
             function isNodeModulesFile(path: string): boolean {
-                const node_modulesFolderName = "/node_modules/";
-
-                return stringContains(path, node_modulesFolderName);
+                return stringContains(path, "/node_modules/");
             }
         }
 
@@ -2001,7 +2089,7 @@ namespace ts {
                 program: getProgram(),
                 newLineCharacter: formatOptions ? formatOptions.newLineCharacter : host.getNewLine(),
                 host,
-                rulesProvider: getRuleProvider(formatOptions),
+                formatContext: formatting.getFormatContext(formatOptions),
                 cancellationToken,
             };
         }
@@ -2040,6 +2128,7 @@ namespace ts {
             getSignatureHelpItems,
             getQuickInfoAtPosition,
             getDefinitionAtPosition,
+            getDefinitionAndBoundSpan,
             getImplementationAtPosition,
             getTypeDefinitionAtPosition,
             getReferencesAtPosition,
diff --git a/src/services/shims.ts b/src/services/shims.ts
index 6e979e22023..7c932361c10 100644
--- a/src/services/shims.ts
+++ b/src/services/shims.ts
@@ -106,7 +106,7 @@ namespace ts {
     ///
     // Note: This is being using by the host (VS) and is marshaled back and forth.
     // When changing this make sure the changes are reflected in the managed side as well
-    export interface IFileReference {
+    export interface ShimsFileReference {
         path: string;
         position: number;
         length: number;
@@ -140,8 +140,8 @@ namespace ts {
         getEncodedSyntacticClassifications(fileName: string, start: number, length: number): string;
         getEncodedSemanticClassifications(fileName: string, start: number, length: number): string;
 
-        getCompletionsAtPosition(fileName: string, position: number): string;
-        getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: string/*Services.FormatCodeOptions*/): string;
+        getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined): string;
+        getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: string/*Services.FormatCodeOptions*/, source: string | undefined): string;
 
         getQuickInfoAtPosition(fileName: string, position: number): string;
 
@@ -170,6 +170,8 @@ namespace ts {
          */
         getDefinitionAtPosition(fileName: string, position: number): string;
 
+        getDefinitionAndBoundSpan(fileName: string, position: number): string;
+
         /**
          * Returns a JSON-encoded value of the type:
          * { fileName: string; textSpan: { start: number; length: number}; kind: string; name: string; containerKind: string; containerName: string }
@@ -772,6 +774,17 @@ namespace ts {
             );
         }
 
+        /**
+         * Computes the definition location and file for the symbol
+         * at the requested position.
+         */
+        public getDefinitionAndBoundSpan(fileName: string, position: number): string {
+            return this.forwardJSONCall(
+                `getDefinitionAndBoundSpan('${fileName}', ${position})`,
+                () => this.languageService.getDefinitionAndBoundSpan(fileName, position)
+            );
+        }
+
         /// GOTO Type
 
         /**
@@ -885,20 +898,20 @@ namespace ts {
          * to provide at the given source position and providing a member completion
          * list if requested.
          */
-        public getCompletionsAtPosition(fileName: string, position: number) {
+        public getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined) {
             return this.forwardJSONCall(
-                `getCompletionsAtPosition('${fileName}', ${position})`,
-                () => this.languageService.getCompletionsAtPosition(fileName, position)
+                `getCompletionsAtPosition('${fileName}', ${position}, ${options})`,
+                () => this.languageService.getCompletionsAtPosition(fileName, position, options)
             );
         }
 
         /** Get a string based representation of a completion list entry details */
-        public getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: string/*Services.FormatCodeOptions*/) {
+        public getCompletionEntryDetails(fileName: string, position: number, entryName: string, options: string/*Services.FormatCodeOptions*/, source: string | undefined) {
             return this.forwardJSONCall(
                 `getCompletionEntryDetails('${fileName}', ${position}, '${entryName}')`,
                 () => {
                     const localOptions: ts.FormatCodeOptions = JSON.parse(options);
-                    return this.languageService.getCompletionEntryDetails(fileName, position, entryName, localOptions);
+                    return this.languageService.getCompletionEntryDetails(fileName, position, entryName, localOptions, source);
                 }
             );
         }
@@ -1091,11 +1104,11 @@ namespace ts {
             );
         }
 
-        private convertFileReferences(refs: FileReference[]): IFileReference[] {
+        private convertFileReferences(refs: FileReference[]): ShimsFileReference[] {
             if (!refs) {
                 return undefined;
             }
-            const result: IFileReference[] = [];
+            const result: ShimsFileReference[] = [];
             for (const ref of refs) {
                 result.push({
                     path: normalizeSlashes(ref.fileName),
diff --git a/src/services/signatureHelp.ts b/src/services/signatureHelp.ts
index 7e8e748bb17..36c83f5f4af 100644
--- a/src/services/signatureHelp.ts
+++ b/src/services/signatureHelp.ts
@@ -400,7 +400,7 @@ namespace ts.SignatureHelp {
                 suffixDisplayParts,
                 separatorDisplayParts: [punctuationPart(SyntaxKind.CommaToken), spacePart()],
                 parameters: signatureHelpParameters,
-                documentation: candidateSignature.getDocumentationComment(),
+                documentation: candidateSignature.getDocumentationComment(typeChecker),
                 tags: candidateSignature.getJsDocTags()
             };
         });
@@ -420,7 +420,7 @@ namespace ts.SignatureHelp {
 
             return {
                 name: parameter.name,
-                documentation: parameter.getDocumentationComment(),
+                documentation: parameter.getDocumentationComment(typeChecker),
                 displayParts,
                 isOptional: typeChecker.isOptionalParameter(<ParameterDeclaration>parameter.valueDeclaration)
             };
@@ -438,4 +438,4 @@ namespace ts.SignatureHelp {
             };
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/services/symbolDisplay.ts b/src/services/symbolDisplay.ts
index d38d21f1092..fe04342b8f7 100644
--- a/src/services/symbolDisplay.ts
+++ b/src/services/symbolDisplay.ts
@@ -75,10 +75,16 @@ namespace ts.SymbolDisplay {
                 }
                 return unionPropertyKind;
             }
-            if (location.parent && isJsxAttribute(location.parent)) {
-                return ScriptElementKind.jsxAttribute;
+            // If we requested completions after `x.` at the top-level, we may be at a source file location.
+            switch (location.parent && location.parent.kind) {
+                // If we've typed a character of the attribute name, will be 'JsxAttribute', else will be 'JsxOpeningElement'.
+                case SyntaxKind.JsxOpeningElement:
+                    return location.kind === SyntaxKind.Identifier ? ScriptElementKind.memberVariableElement : ScriptElementKind.jsxAttribute;
+                case SyntaxKind.JsxAttribute:
+                    return ScriptElementKind.jsxAttribute;
+                default:
+                    return ScriptElementKind.memberVariableElement;
             }
-            return ScriptElementKind.memberVariableElement;
         }
 
         return ScriptElementKind.unknown;
@@ -90,9 +96,16 @@ namespace ts.SymbolDisplay {
             : ScriptElementKindModifier.none;
     }
 
+    interface SymbolDisplayPartsDocumentationAndSymbolKind {
+        displayParts: SymbolDisplayPart[];
+        documentation: SymbolDisplayPart[];
+        symbolKind: ScriptElementKind;
+        tags: JSDocTagInfo[];
+    }
+
     // TODO(drosen): Currently completion entry details passes the SemanticMeaning.All instead of using semanticMeaning of location
     export function getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker: TypeChecker, symbol: Symbol, sourceFile: SourceFile, enclosingDeclaration: Node,
-        location: Node, semanticMeaning = getMeaningFromLocation(location)) {
+        location: Node, semanticMeaning = getMeaningFromLocation(location)): SymbolDisplayPartsDocumentationAndSymbolKind {
 
         const displayParts: SymbolDisplayPart[] = [];
         let documentation: SymbolDisplayPart[];
@@ -178,13 +191,14 @@ namespace ts.SymbolDisplay {
                             // If it is call or construct signature of lambda's write type name
                             displayParts.push(punctuationPart(SyntaxKind.ColonToken));
                             displayParts.push(spacePart());
+                            if (!(type.flags & TypeFlags.Object && (<ObjectType>type).objectFlags & ObjectFlags.Anonymous) && type.symbol) {
+                                addRange(displayParts, symbolToDisplayParts(typeChecker, type.symbol, enclosingDeclaration, /*meaning*/ undefined, SymbolFormatFlags.WriteTypeParametersOrArguments));
+                                displayParts.push(lineBreakPart());
+                            }
                             if (useConstructSignatures) {
                                 displayParts.push(keywordPart(SyntaxKind.NewKeyword));
                                 displayParts.push(spacePart());
                             }
-                            if (!(type.flags & TypeFlags.Object && (<ObjectType>type).objectFlags & ObjectFlags.Anonymous) && type.symbol) {
-                                addRange(displayParts, symbolToDisplayParts(typeChecker, type.symbol, enclosingDeclaration, /*meaning*/ undefined, SymbolFormatFlags.WriteTypeParametersOrArguments));
-                            }
                             addSignatureDisplayParts(signature, allSignatures, TypeFormatFlags.WriteArrowStyleSignature);
                             break;
 
@@ -431,7 +445,7 @@ namespace ts.SymbolDisplay {
         }
 
         if (!documentation) {
-            documentation = symbol.getDocumentationComment();
+            documentation = symbol.getDocumentationComment(typeChecker);
             tags = symbol.getJsDocTags();
             if (documentation.length === 0 && symbolFlags & SymbolFlags.Property) {
                 // For some special property access expressions like `exports.foo = foo` or `module.exports.foo = foo`
@@ -448,7 +462,7 @@ namespace ts.SymbolDisplay {
                             continue;
                         }
 
-                        documentation = rhsSymbol.getDocumentationComment();
+                        documentation = rhsSymbol.getDocumentationComment(typeChecker);
                         tags = rhsSymbol.getJsDocTags();
                         if (documentation.length > 0) {
                             break;
@@ -482,8 +496,10 @@ namespace ts.SymbolDisplay {
             addNewLineIfDisplayPartsExist();
             if (symbolKind) {
                 pushTypePart(symbolKind);
-                displayParts.push(spacePart());
-                addFullSymbolName(symbol);
+                if (!some(symbol.declarations, d => isArrowFunction(d) || (isFunctionExpression(d) || isClassExpression(d)) && !d.name)) {
+                    displayParts.push(spacePart());
+                    addFullSymbolName(symbol);
+                }
             }
         }
 
@@ -515,7 +531,7 @@ namespace ts.SymbolDisplay {
                 displayParts.push(textPart(allSignatures.length === 2 ? "overload" : "overloads"));
                 displayParts.push(punctuationPart(SyntaxKind.CloseParenToken));
             }
-            documentation = signature.getDocumentationComment();
+            documentation = signature.getDocumentationComment(typeChecker);
             tags = signature.getJsDocTags();
         }
 
diff --git a/src/services/textChanges.ts b/src/services/textChanges.ts
index bc3a8e27ef0..7c4e25537ef 100644
--- a/src/services/textChanges.ts
+++ b/src/services/textChanges.ts
@@ -188,7 +188,7 @@ namespace ts.textChanges {
 
     export interface TextChangesContext {
         newLineCharacter: string;
-        rulesProvider: formatting.RulesProvider;
+        formatContext: ts.formatting.FormatContext;
     }
 
     export class ChangeTracker {
@@ -196,7 +196,7 @@ namespace ts.textChanges {
         private readonly newLineCharacter: string;
 
         public static fromContext(context: TextChangesContext): ChangeTracker {
-            return new ChangeTracker(context.newLineCharacter === "\n" ? NewLineKind.LineFeed : NewLineKind.CarriageReturnLineFeed, context.rulesProvider);
+            return new ChangeTracker(context.newLineCharacter === "\n" ? NewLineKind.LineFeed : NewLineKind.CarriageReturnLineFeed, context.formatContext);
         }
 
         public static with(context: TextChangesContext, cb: (tracker: ChangeTracker) => void): FileTextChanges[] {
@@ -207,7 +207,7 @@ namespace ts.textChanges {
 
         constructor(
             private readonly newLine: NewLineKind,
-            private readonly rulesProvider: formatting.RulesProvider,
+            private readonly formatContext: ts.formatting.FormatContext,
             private readonly validator?: (text: NonFormattedText) => void) {
             this.newLineCharacter = getNewLineCharacter({ newLine });
         }
@@ -475,7 +475,7 @@ namespace ts.textChanges {
                         options: {}
                     });
                     // use the same indentation as 'after' item
-                    const indentation = formatting.SmartIndenter.findFirstNonWhitespaceColumn(afterStartLinePosition, afterStart, sourceFile, this.rulesProvider.getFormatOptions());
+                    const indentation = formatting.SmartIndenter.findFirstNonWhitespaceColumn(afterStartLinePosition, afterStart, sourceFile, this.formatContext.options);
                     // insert element before the line break on the line that contains 'after' element
                     let insertPos = skipTrivia(sourceFile.text, end, /*stopAfterLineBreak*/ true, /*stopAtComments*/ false);
                     if (insertPos !== end && isLineBreak(sourceFile.text.charCodeAt(insertPos - 1))) {
@@ -562,7 +562,7 @@ namespace ts.textChanges {
                 this.validator(nonformattedText);
             }
 
-            const formatOptions = this.rulesProvider.getFormatOptions();
+            const { options: formatOptions } = this.formatContext;
             const posStartsLine = getLineStartPositionForPosition(pos, sourceFile) === pos;
 
             const initialIndentation =
@@ -578,7 +578,7 @@ namespace ts.textChanges {
                         ? (formatOptions.indentSize || 0)
                         : 0;
 
-            return applyFormatting(nonformattedText, sourceFile, initialIndentation, delta, this.rulesProvider);
+            return applyFormatting(nonformattedText, sourceFile, initialIndentation, delta, this.formatContext);
         }
 
         private static normalize(changes: Change[]): Change[] {
@@ -605,14 +605,14 @@ namespace ts.textChanges {
         return { text: writer.getText(), node: assignPositionsToNode(node) };
     }
 
-    function applyFormatting(nonFormattedText: NonFormattedText, sourceFile: SourceFile, initialIndentation: number, delta: number, rulesProvider: formatting.RulesProvider) {
+    function applyFormatting(nonFormattedText: NonFormattedText, sourceFile: SourceFile, initialIndentation: number, delta: number, formatContext: ts.formatting.FormatContext) {
         const lineMap = computeLineStarts(nonFormattedText.text);
         const file: SourceFileLike = {
             text: nonFormattedText.text,
             lineMap,
             getLineAndCharacterOfPosition: pos => computeLineAndCharacterOfPosition(lineMap, pos)
         };
-        const changes = formatting.formatNodeGivenIndentation(nonFormattedText.node, file, sourceFile.languageVariant, initialIndentation, delta, rulesProvider);
+        const changes = formatting.formatNodeGivenIndentation(nonFormattedText.node, file, sourceFile.languageVariant, initialIndentation, delta, formatContext);
         return applyChanges(nonFormattedText.text, changes);
     }
 
diff --git a/src/services/types.ts b/src/services/types.ts
index c854eb8aacc..a9244982fbb 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -5,9 +5,11 @@ namespace ts {
         getChildAt(index: number, sourceFile?: SourceFile): Node;
         getChildren(sourceFile?: SourceFile): Node[];
         /* @internal */
+        // tslint:disable-next-line unified-signatures
         getChildren(sourceFile?: SourceFileLike): Node[];
         getStart(sourceFile?: SourceFile, includeJsDocComment?: boolean): number;
         /* @internal */
+        // tslint:disable-next-line unified-signatures
         getStart(sourceFile?: SourceFileLike, includeJsDocComment?: boolean): number;
         getFullStart(): number;
         getEnd(): number;
@@ -32,7 +34,7 @@ namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
 
@@ -55,7 +57,7 @@ namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
 
@@ -86,6 +88,7 @@ namespace ts {
      * snapshot is observably immutable. i.e. the same calls with the same parameters will return
      * the same values.
      */
+    // tslint:disable-next-line interface-name
     export interface IScriptSnapshot {
         /** Gets a portion of the script snapshot specified by [start, end). */
         getText(start: number, end: number): string;
@@ -236,10 +239,16 @@ namespace ts {
         getEncodedSyntacticClassifications(fileName: string, span: TextSpan): Classifications;
         getEncodedSemanticClassifications(fileName: string, span: TextSpan): Classifications;
 
-        getCompletionsAtPosition(fileName: string, position: number): CompletionInfo;
+        getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined): CompletionInfo;
         // "options" and "source" are optional only for backwards-compatibility
-        getCompletionEntryDetails(fileName: string, position: number, name: string, options?: FormatCodeOptions | FormatCodeSettings, source?: string): CompletionEntryDetails;
-        getCompletionEntrySymbol(fileName: string, position: number, name: string, source?: string): Symbol;
+        getCompletionEntryDetails(
+            fileName: string,
+            position: number,
+            name: string,
+            options: FormatCodeOptions | FormatCodeSettings | undefined,
+            source: string | undefined,
+        ): CompletionEntryDetails;
+        getCompletionEntrySymbol(fileName: string, position: number, name: string, source: string | undefined): Symbol;
 
         getQuickInfoAtPosition(fileName: string, position: number): QuickInfo;
 
@@ -253,6 +262,7 @@ namespace ts {
         findRenameLocations(fileName: string, position: number, findInStrings: boolean, findInComments: boolean): RenameLocation[];
 
         getDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
+        getDefinitionAndBoundSpan(fileName: string, position: number): DefinitionInfoAndBoundSpan;
         getTypeDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
         getImplementationAtPosition(fileName: string, position: number): ImplementationLocation[];
 
@@ -302,6 +312,10 @@ namespace ts {
         dispose(): void;
     }
 
+    export interface GetCompletionsAtPositionOptions {
+        includeExternalModuleExports: boolean;
+    }
+
     export interface ApplyCodeActionCommandResult {
         successMessage: string;
     }
@@ -575,6 +589,11 @@ namespace ts {
         containerName: string;
     }
 
+    export interface DefinitionInfoAndBoundSpan {
+        definitions: ReadonlyArray<DefinitionInfo>;
+        textSpan: TextSpan;
+    }
+
     export interface ReferencedSymbolDefinitionInfo extends DefinitionInfo {
         displayParts: SymbolDisplayPart[];
     }
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 2b116eb1cd0..1ed44d29f95 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -178,7 +178,7 @@ namespace ts {
 
         switch (node.kind) {
             case SyntaxKind.ThisKeyword:
-                return !isPartOfExpression(node);
+                return !isExpressionNode(node);
             case SyntaxKind.ThisType:
                 return true;
         }
@@ -947,7 +947,7 @@ namespace ts {
         if (flags & ModifierFlags.Static) result.push(ScriptElementKindModifier.staticModifier);
         if (flags & ModifierFlags.Abstract) result.push(ScriptElementKindModifier.abstractModifier);
         if (flags & ModifierFlags.Export) result.push(ScriptElementKindModifier.exportedModifier);
-        if (isInAmbientContext(node)) result.push(ScriptElementKindModifier.ambientModifier);
+        if (node.flags & NodeFlags.Ambient) result.push(ScriptElementKindModifier.ambientModifier);
 
         return result.length > 0 ? result.join(",") : ScriptElementKindModifier.none;
     }
@@ -1068,20 +1068,19 @@ namespace ts {
         return createTextSpanFromBounds(range.pos, range.end);
     }
 
+    export const typeKeywords: ReadonlyArray<SyntaxKind> = [
+        SyntaxKind.AnyKeyword,
+        SyntaxKind.BooleanKeyword,
+        SyntaxKind.NeverKeyword,
+        SyntaxKind.NumberKeyword,
+        SyntaxKind.ObjectKeyword,
+        SyntaxKind.StringKeyword,
+        SyntaxKind.SymbolKeyword,
+        SyntaxKind.VoidKeyword,
+    ];
+
     export function isTypeKeyword(kind: SyntaxKind): boolean {
-        switch (kind) {
-            case SyntaxKind.AnyKeyword:
-            case SyntaxKind.BooleanKeyword:
-            case SyntaxKind.NeverKeyword:
-            case SyntaxKind.NumberKeyword:
-            case SyntaxKind.ObjectKeyword:
-            case SyntaxKind.StringKeyword:
-            case SyntaxKind.SymbolKeyword:
-            case SyntaxKind.VoidKeyword:
-                return true;
-            default:
-                return false;
-        }
+        return contains(typeKeywords, kind);
     }
 
     /** True if the symbol is for an external module, as opposed to a namespace. */
@@ -1330,23 +1329,39 @@ namespace ts {
     export function getSourceFileImportLocation(node: SourceFile) {
         // For a source file, it is possible there are detached comments we should not skip
         const text = node.text;
+        const textLength = text.length;
         let ranges = getLeadingCommentRanges(text, 0);
         if (!ranges) return 0;
         let position = 0;
         // However we should still skip a pinned comment at the top
         if (ranges.length && ranges[0].kind === SyntaxKind.MultiLineCommentTrivia && isPinnedComment(text, ranges[0])) {
-            position = ranges[0].end + 1;
+            position = ranges[0].end;
+            advancePastLineBreak();
             ranges = ranges.slice(1);
         }
         // As well as any triple slash references
         for (const range of ranges) {
             if (range.kind === SyntaxKind.SingleLineCommentTrivia && isRecognizedTripleSlashComment(node.text, range.pos, range.end)) {
-                position = range.end + 1;
+                position = range.end;
+                advancePastLineBreak();
                 continue;
             }
             break;
         }
         return position;
+
+        function advancePastLineBreak() {
+            if (position < textLength) {
+                const charCode = text.charCodeAt(position);
+                if (isLineBreak(charCode)) {
+                    position++;
+
+                    if (position < textLength && charCode === CharacterCodes.carriageReturn && text.charCodeAt(position) === CharacterCodes.lineFeed) {
+                        position++;
+                    }
+                }
+            }
+        }
     }
 
     /**
@@ -1398,7 +1413,9 @@ namespace ts {
             addEmitFlags(node, EmitFlags.NoLeadingComments);
 
             const firstChild = forEachChild(node, child => child);
-            firstChild && suppressLeading(firstChild);
+            if (firstChild) {
+                suppressLeading(firstChild);
+            }
         }
 
         function suppressTrailing(node: Node) {
@@ -1415,7 +1432,9 @@ namespace ts {
                     }
                     return undefined;
                 });
-            lastChild && suppressTrailing(lastChild);
+            if (lastChild) {
+                suppressTrailing(lastChild);
+            }
         }
     }
 }
diff --git a/tests/baselines/reference/APISample_jsdoc.js b/tests/baselines/reference/APISample_jsdoc.js
index c74e188f38b..f28b16d88b6 100644
--- a/tests/baselines/reference/APISample_jsdoc.js
+++ b/tests/baselines/reference/APISample_jsdoc.js
@@ -21,7 +21,7 @@ function parseCommentsIntoDefinition(this: any,
     }
 
     // the comments for a symbol
-    let comments = symbol.getDocumentationComment();
+    let comments = symbol.getDocumentationComment(undefined);
 
     if (comments.length) {
         definition.description = comments.map(comment => comment.kind === "lineBreak" ? comment.text : comment.text.trim().replace(/\r\n/g, "\n")).join("");
@@ -131,7 +131,7 @@ function parseCommentsIntoDefinition(symbol, definition, otherAnnotations) {
         return;
     }
     // the comments for a symbol
-    var comments = symbol.getDocumentationComment();
+    var comments = symbol.getDocumentationComment(undefined);
     if (comments.length) {
         definition.description = comments.map(function (comment) { return comment.kind === "lineBreak" ? comment.text : comment.text.trim().replace(/\r\n/g, "\n"); }).join("");
     }
diff --git a/tests/baselines/reference/abstractClassInLocalScopeIsAbstract.errors.txt b/tests/baselines/reference/abstractClassInLocalScopeIsAbstract.errors.txt
index f5c5b417ea3..fa02cb21d34 100644
--- a/tests/baselines/reference/abstractClassInLocalScopeIsAbstract.errors.txt
+++ b/tests/baselines/reference/abstractClassInLocalScopeIsAbstract.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/abstractClassInLocalScopeIsAbstract.ts(4,5): error TS2511: Cannot create an instance of the abstract class 'A'.
+tests/cases/compiler/abstractClassInLocalScopeIsAbstract.ts(4,5): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/compiler/abstractClassInLocalScopeIsAbstract.ts (1 errors) ====
@@ -7,7 +7,7 @@ tests/cases/compiler/abstractClassInLocalScopeIsAbstract.ts(4,5): error TS2511:
         class B extends A {}
         new A();
         ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
         new B();
     })()
     
\ No newline at end of file
diff --git a/tests/baselines/reference/abstractPropertyInConstructor.errors.txt b/tests/baselines/reference/abstractPropertyInConstructor.errors.txt
index 461dd713d3b..0798d91ce78 100644
--- a/tests/baselines/reference/abstractPropertyInConstructor.errors.txt
+++ b/tests/baselines/reference/abstractPropertyInConstructor.errors.txt
@@ -5,7 +5,7 @@ tests/cases/compiler/abstractPropertyInConstructor.ts(9,14): error TS2715: Abstr
 
 ==== tests/cases/compiler/abstractPropertyInConstructor.ts (3 errors) ====
     abstract class AbstractClass {
-        constructor(str: string) {
+        constructor(str: string, other: AbstractClass) {
             this.method(parseInt(str));
             let val = this.prop.toLowerCase();
                            ~~~~
@@ -20,9 +20,13 @@ tests/cases/compiler/abstractPropertyInConstructor.ts(9,14): error TS2715: Abstr
                  ~~
 !!! error TS2715: Abstract property 'cb' in class 'AbstractClass' cannot be accessed in the constructor.
     
+            // OK, reference is inside function
             const innerFunction = () => {
                 return this.prop;
             }
+    
+            // OK, references are to another instance
+            other.cb(other.prop);
         }
     
         abstract prop: string;
@@ -34,4 +38,13 @@ tests/cases/compiler/abstractPropertyInConstructor.ts(9,14): error TS2715: Abstr
             this.prop = this.prop + "!";
         }
     }
+    
+    class User {
+        constructor(a: AbstractClass) {
+            a.prop;
+            a.cb("hi");
+            a.method(12);
+            a.method2();
+        }
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/abstractPropertyInConstructor.js b/tests/baselines/reference/abstractPropertyInConstructor.js
index 18a2937a191..5a4feda110f 100644
--- a/tests/baselines/reference/abstractPropertyInConstructor.js
+++ b/tests/baselines/reference/abstractPropertyInConstructor.js
@@ -1,6 +1,6 @@
 //// [abstractPropertyInConstructor.ts]
 abstract class AbstractClass {
-    constructor(str: string) {
+    constructor(str: string, other: AbstractClass) {
         this.method(parseInt(str));
         let val = this.prop.toLowerCase();
 
@@ -9,9 +9,13 @@ abstract class AbstractClass {
         }
         this.cb(str);
 
+        // OK, reference is inside function
         const innerFunction = () => {
             return this.prop;
         }
+
+        // OK, references are to another instance
+        other.cb(other.prop);
     }
 
     abstract prop: string;
@@ -23,11 +27,20 @@ abstract class AbstractClass {
         this.prop = this.prop + "!";
     }
 }
+
+class User {
+    constructor(a: AbstractClass) {
+        a.prop;
+        a.cb("hi");
+        a.method(12);
+        a.method2();
+    }
+}
 
 
 //// [abstractPropertyInConstructor.js]
 var AbstractClass = /** @class */ (function () {
-    function AbstractClass(str) {
+    function AbstractClass(str, other) {
         var _this = this;
         this.method(parseInt(str));
         var val = this.prop.toLowerCase();
@@ -35,12 +48,24 @@ var AbstractClass = /** @class */ (function () {
             this.prop = "Hello World";
         }
         this.cb(str);
+        // OK, reference is inside function
         var innerFunction = function () {
             return _this.prop;
         };
+        // OK, references are to another instance
+        other.cb(other.prop);
     }
     AbstractClass.prototype.method2 = function () {
         this.prop = this.prop + "!";
     };
     return AbstractClass;
 }());
+var User = /** @class */ (function () {
+    function User(a) {
+        a.prop;
+        a.cb("hi");
+        a.method(12);
+        a.method2();
+    }
+    return User;
+}());
diff --git a/tests/baselines/reference/abstractPropertyInConstructor.symbols b/tests/baselines/reference/abstractPropertyInConstructor.symbols
index 0d542ffb0a8..42cd3bb6827 100644
--- a/tests/baselines/reference/abstractPropertyInConstructor.symbols
+++ b/tests/baselines/reference/abstractPropertyInConstructor.symbols
@@ -2,69 +2,110 @@
 abstract class AbstractClass {
 >AbstractClass : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
 
-    constructor(str: string) {
+    constructor(str: string, other: AbstractClass) {
 >str : Symbol(str, Decl(abstractPropertyInConstructor.ts, 1, 16))
+>other : Symbol(other, Decl(abstractPropertyInConstructor.ts, 1, 28))
+>AbstractClass : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
 
         this.method(parseInt(str));
->this.method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 16, 37))
+>this.method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 20, 37))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 16, 37))
+>method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 20, 37))
 >parseInt : Symbol(parseInt, Decl(lib.d.ts, --, --))
 >str : Symbol(str, Decl(abstractPropertyInConstructor.ts, 1, 16))
 
         let val = this.prop.toLowerCase();
 >val : Symbol(val, Decl(abstractPropertyInConstructor.ts, 3, 11))
 >this.prop.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
->this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
 
         if (!str) {
 >str : Symbol(str, Decl(abstractPropertyInConstructor.ts, 1, 16))
 
             this.prop = "Hello World";
->this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
         }
         this.cb(str);
->this.cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 15, 26))
+>this.cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 15, 26))
+>cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
 >str : Symbol(str, Decl(abstractPropertyInConstructor.ts, 1, 16))
 
+        // OK, reference is inside function
         const innerFunction = () => {
->innerFunction : Symbol(innerFunction, Decl(abstractPropertyInConstructor.ts, 10, 13))
+>innerFunction : Symbol(innerFunction, Decl(abstractPropertyInConstructor.ts, 11, 13))
 
             return this.prop;
->this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
         }
+
+        // OK, references are to another instance
+        other.cb(other.prop);
+>other.cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
+>other : Symbol(other, Decl(abstractPropertyInConstructor.ts, 1, 28))
+>cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
+>other.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
+>other : Symbol(other, Decl(abstractPropertyInConstructor.ts, 1, 28))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
     }
 
     abstract prop: string;
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 
     abstract cb: (s: string) => void;
->cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 15, 26))
->s : Symbol(s, Decl(abstractPropertyInConstructor.ts, 16, 18))
+>cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
+>s : Symbol(s, Decl(abstractPropertyInConstructor.ts, 20, 18))
 
     abstract method(num: number): void;
->method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 16, 37))
->num : Symbol(num, Decl(abstractPropertyInConstructor.ts, 18, 20))
+>method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 20, 37))
+>num : Symbol(num, Decl(abstractPropertyInConstructor.ts, 22, 20))
 
     method2() {
->method2 : Symbol(AbstractClass.method2, Decl(abstractPropertyInConstructor.ts, 18, 39))
+>method2 : Symbol(AbstractClass.method2, Decl(abstractPropertyInConstructor.ts, 22, 39))
 
         this.prop = this.prop + "!";
->this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
->this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
+>this.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
 >this : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
->prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 13, 5))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
+    }
+}
+
+class User {
+>User : Symbol(User, Decl(abstractPropertyInConstructor.ts, 27, 1))
+
+    constructor(a: AbstractClass) {
+>a : Symbol(a, Decl(abstractPropertyInConstructor.ts, 30, 16))
+>AbstractClass : Symbol(AbstractClass, Decl(abstractPropertyInConstructor.ts, 0, 0))
+
+        a.prop;
+>a.prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
+>a : Symbol(a, Decl(abstractPropertyInConstructor.ts, 30, 16))
+>prop : Symbol(AbstractClass.prop, Decl(abstractPropertyInConstructor.ts, 17, 5))
+
+        a.cb("hi");
+>a.cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
+>a : Symbol(a, Decl(abstractPropertyInConstructor.ts, 30, 16))
+>cb : Symbol(AbstractClass.cb, Decl(abstractPropertyInConstructor.ts, 19, 26))
+
+        a.method(12);
+>a.method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 20, 37))
+>a : Symbol(a, Decl(abstractPropertyInConstructor.ts, 30, 16))
+>method : Symbol(AbstractClass.method, Decl(abstractPropertyInConstructor.ts, 20, 37))
+
+        a.method2();
+>a.method2 : Symbol(AbstractClass.method2, Decl(abstractPropertyInConstructor.ts, 22, 39))
+>a : Symbol(a, Decl(abstractPropertyInConstructor.ts, 30, 16))
+>method2 : Symbol(AbstractClass.method2, Decl(abstractPropertyInConstructor.ts, 22, 39))
     }
 }
 
diff --git a/tests/baselines/reference/abstractPropertyInConstructor.types b/tests/baselines/reference/abstractPropertyInConstructor.types
index 0ffb5f1bdfd..6f8970a7702 100644
--- a/tests/baselines/reference/abstractPropertyInConstructor.types
+++ b/tests/baselines/reference/abstractPropertyInConstructor.types
@@ -2,8 +2,10 @@
 abstract class AbstractClass {
 >AbstractClass : AbstractClass
 
-    constructor(str: string) {
+    constructor(str: string, other: AbstractClass) {
 >str : string
+>other : AbstractClass
+>AbstractClass : AbstractClass
 
         this.method(parseInt(str));
 >this.method(parseInt(str)) : void
@@ -41,6 +43,7 @@ abstract class AbstractClass {
 >cb : (s: string) => void
 >str : string
 
+        // OK, reference is inside function
         const innerFunction = () => {
 >innerFunction : () => string
 >() => {            return this.prop;        } : () => string
@@ -50,6 +53,16 @@ abstract class AbstractClass {
 >this : this
 >prop : string
         }
+
+        // OK, references are to another instance
+        other.cb(other.prop);
+>other.cb(other.prop) : void
+>other.cb : (s: string) => void
+>other : AbstractClass
+>cb : (s: string) => void
+>other.prop : string
+>other : AbstractClass
+>prop : string
     }
 
     abstract prop: string;
@@ -79,3 +92,37 @@ abstract class AbstractClass {
     }
 }
 
+class User {
+>User : User
+
+    constructor(a: AbstractClass) {
+>a : AbstractClass
+>AbstractClass : AbstractClass
+
+        a.prop;
+>a.prop : string
+>a : AbstractClass
+>prop : string
+
+        a.cb("hi");
+>a.cb("hi") : void
+>a.cb : (s: string) => void
+>a : AbstractClass
+>cb : (s: string) => void
+>"hi" : "hi"
+
+        a.method(12);
+>a.method(12) : void
+>a.method : (num: number) => void
+>a : AbstractClass
+>method : (num: number) => void
+>12 : 12
+
+        a.method2();
+>a.method2() : void
+>a.method2 : () => void
+>a : AbstractClass
+>method2 : () => void
+    }
+}
+
diff --git a/tests/baselines/reference/ambientDeclarationsExternal.js b/tests/baselines/reference/ambientDeclarationsExternal.js
index fb531586467..ed413fb0d8e 100644
--- a/tests/baselines/reference/ambientDeclarationsExternal.js
+++ b/tests/baselines/reference/ambientDeclarationsExternal.js
@@ -24,7 +24,7 @@ var n: number;
 
 
 //// [decls.js]
-// Ambient external import declaration referencing ambient external module using top level module name 
+// Ambient external import declaration referencing ambient external module using top level module name
 //// [consumer.js]
 "use strict";
 exports.__esModule = true;
diff --git a/tests/baselines/reference/anyAssignableToEveryType.js b/tests/baselines/reference/anyAssignableToEveryType.js
index d6b2303de48..eff97905e4f 100644
--- a/tests/baselines/reference/anyAssignableToEveryType.js
+++ b/tests/baselines/reference/anyAssignableToEveryType.js
@@ -87,4 +87,4 @@ function foo(x, y, z) {
 //    x = a;
 //    y = a;
 //    z = a;
-//} 
+//}
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 44c8095b9fb..f98684b3c68 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -313,46 +313,49 @@ declare namespace ts {
         JsxSelfClosingElement = 250,
         JsxOpeningElement = 251,
         JsxClosingElement = 252,
-        JsxAttribute = 253,
-        JsxAttributes = 254,
-        JsxSpreadAttribute = 255,
-        JsxExpression = 256,
-        CaseClause = 257,
-        DefaultClause = 258,
-        HeritageClause = 259,
-        CatchClause = 260,
-        PropertyAssignment = 261,
-        ShorthandPropertyAssignment = 262,
-        SpreadAssignment = 263,
-        EnumMember = 264,
-        SourceFile = 265,
-        Bundle = 266,
-        JSDocTypeExpression = 267,
-        JSDocAllType = 268,
-        JSDocUnknownType = 269,
-        JSDocNullableType = 270,
-        JSDocNonNullableType = 271,
-        JSDocOptionalType = 272,
-        JSDocFunctionType = 273,
-        JSDocVariadicType = 274,
-        JSDocComment = 275,
-        JSDocTag = 276,
-        JSDocAugmentsTag = 277,
-        JSDocClassTag = 278,
-        JSDocParameterTag = 279,
-        JSDocReturnTag = 280,
-        JSDocTypeTag = 281,
-        JSDocTemplateTag = 282,
-        JSDocTypedefTag = 283,
-        JSDocPropertyTag = 284,
-        JSDocTypeLiteral = 285,
-        SyntaxList = 286,
-        NotEmittedStatement = 287,
-        PartiallyEmittedExpression = 288,
-        CommaListExpression = 289,
-        MergeDeclarationMarker = 290,
-        EndOfDeclarationMarker = 291,
-        Count = 292,
+        JsxFragment = 253,
+        JsxOpeningFragment = 254,
+        JsxClosingFragment = 255,
+        JsxAttribute = 256,
+        JsxAttributes = 257,
+        JsxSpreadAttribute = 258,
+        JsxExpression = 259,
+        CaseClause = 260,
+        DefaultClause = 261,
+        HeritageClause = 262,
+        CatchClause = 263,
+        PropertyAssignment = 264,
+        ShorthandPropertyAssignment = 265,
+        SpreadAssignment = 266,
+        EnumMember = 267,
+        SourceFile = 268,
+        Bundle = 269,
+        JSDocTypeExpression = 270,
+        JSDocAllType = 271,
+        JSDocUnknownType = 272,
+        JSDocNullableType = 273,
+        JSDocNonNullableType = 274,
+        JSDocOptionalType = 275,
+        JSDocFunctionType = 276,
+        JSDocVariadicType = 277,
+        JSDocComment = 278,
+        JSDocTypeLiteral = 279,
+        JSDocTag = 280,
+        JSDocAugmentsTag = 281,
+        JSDocClassTag = 282,
+        JSDocParameterTag = 283,
+        JSDocReturnTag = 284,
+        JSDocTypeTag = 285,
+        JSDocTemplateTag = 286,
+        JSDocTypedefTag = 287,
+        JSDocPropertyTag = 288,
+        SyntaxList = 289,
+        NotEmittedStatement = 290,
+        PartiallyEmittedExpression = 291,
+        CommaListExpression = 292,
+        MergeDeclarationMarker = 293,
+        EndOfDeclarationMarker = 294,
+        Count = 295,
         FirstAssignment = 58,
         LastAssignment = 70,
         FirstCompoundAssignment = 59,
@@ -378,10 +381,10 @@ declare namespace ts {
         FirstBinaryOperator = 27,
         LastBinaryOperator = 70,
         FirstNode = 143,
-        FirstJSDocNode = 267,
-        LastJSDocNode = 285,
-        FirstJSDocTagNode = 276,
-        LastJSDocTagNode = 285,
+        FirstJSDocNode = 270,
+        LastJSDocNode = 288,
+        FirstJSDocTagNode = 280,
+        LastJSDocTagNode = 288,
     }
     enum NodeFlags {
         None = 0,
@@ -408,7 +411,7 @@ declare namespace ts {
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
         ReachabilityAndEmitFlags = 1408,
-        ContextFlags = 2193408,
+        ContextFlags = 6387712,
         TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
@@ -1061,6 +1064,20 @@ declare namespace ts {
         tagName: JsxTagNameExpression;
         attributes: JsxAttributes;
     }
+    interface JsxFragment extends PrimaryExpression {
+        kind: SyntaxKind.JsxFragment;
+        openingFragment: JsxOpeningFragment;
+        children: NodeArray<JsxChild>;
+        closingFragment: JsxClosingFragment;
+    }
+    interface JsxOpeningFragment extends Expression {
+        kind: SyntaxKind.JsxOpeningFragment;
+        parent?: JsxFragment;
+    }
+    interface JsxClosingFragment extends Expression {
+        kind: SyntaxKind.JsxClosingFragment;
+        parent?: JsxFragment;
+    }
     interface JsxAttribute extends ObjectLiteralElement {
         kind: SyntaxKind.JsxAttribute;
         parent?: JsxAttributes;
@@ -1088,7 +1105,7 @@ declare namespace ts {
         containsOnlyWhiteSpaces: boolean;
         parent?: JsxElement;
     }
-    type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement;
+    type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement | JsxFragment;
     interface Statement extends Node {
         _statementBrand: any;
     }
@@ -1592,8 +1609,8 @@ declare namespace ts {
     }
     interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
     interface ParseConfigHost {
@@ -1606,9 +1623,7 @@ declare namespace ts {
         fileExists(path: string): boolean;
         readFile(path: string): string | undefined;
     }
-    interface WriteFileCallback {
-        (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>): void;
-    }
+    type WriteFileCallback = (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>) => void;
     class OperationCanceledException {
     }
     interface CancellationToken {
@@ -2040,6 +2055,7 @@ declare namespace ts {
         ObjectLiteral = 128,
         EvolvingArray = 256,
         ObjectLiteralPatternWithComputedProperties = 512,
+        ContainsSpread = 1024,
         ClassOrInterface = 3,
     }
     interface ObjectType extends Type {
@@ -3001,6 +3017,9 @@ declare namespace ts {
     function isJsxSelfClosingElement(node: Node): node is JsxSelfClosingElement;
     function isJsxOpeningElement(node: Node): node is JsxOpeningElement;
     function isJsxClosingElement(node: Node): node is JsxClosingElement;
+    function isJsxFragment(node: Node): node is JsxFragment;
+    function isJsxOpeningFragment(node: Node): node is JsxOpeningFragment;
+    function isJsxClosingFragment(node: Node): node is JsxClosingFragment;
     function isJsxAttribute(node: Node): node is JsxAttribute;
     function isJsxAttributes(node: Node): node is JsxAttributes;
     function isJsxSpreadAttribute(node: Node): node is JsxSpreadAttribute;
@@ -3074,9 +3093,7 @@ declare namespace ts {
     function isGetAccessor(node: Node): node is GetAccessorDeclaration;
 }
 declare namespace ts {
-    interface ErrorCallback {
-        (message: DiagnosticMessage, length: number): void;
-    }
+    type ErrorCallback = (message: DiagnosticMessage, length: number) => void;
     interface Scanner {
         getStartPos(): number;
         getToken(): SyntaxKind;
@@ -3254,11 +3271,10 @@ declare namespace ts {
 }
 declare namespace ts {
     function createNodeArray<T extends Node>(elements?: ReadonlyArray<T>, hasTrailingComma?: boolean): NodeArray<T>;
-    function createLiteral(value: string): StringLiteral;
+    /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
+    function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: number): NumericLiteral;
     function createLiteral(value: boolean): BooleanLiteral;
-    /** Create a string literal whose source text is read from a source node during emit. */
-    function createLiteral(sourceNode: StringLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: string | number | boolean): PrimaryExpression;
     function createNumericLiteral(value: string): NumericLiteral;
     function createIdentifier(text: string): Identifier;
@@ -3500,6 +3516,8 @@ declare namespace ts {
     function updateJsxOpeningElement(node: JsxOpeningElement, tagName: JsxTagNameExpression, attributes: JsxAttributes): JsxOpeningElement;
     function createJsxClosingElement(tagName: JsxTagNameExpression): JsxClosingElement;
     function updateJsxClosingElement(node: JsxClosingElement, tagName: JsxTagNameExpression): JsxClosingElement;
+    function createJsxFragment(openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment): JsxFragment;
+    function updateJsxFragment(node: JsxFragment, openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment): JsxFragment;
     function createJsxAttribute(name: Identifier, initializer: StringLiteral | JsxExpression): JsxAttribute;
     function updateJsxAttribute(node: JsxAttribute, name: Identifier, initializer: StringLiteral | JsxExpression): JsxAttribute;
     function createJsxAttributes(properties: ReadonlyArray<JsxAttributeLike>): JsxAttributes;
@@ -3794,7 +3812,7 @@ declare namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface Type {
@@ -3815,7 +3833,7 @@ declare namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface SourceFile {
@@ -3914,9 +3932,9 @@ declare namespace ts {
         getSemanticClassifications(fileName: string, span: TextSpan): ClassifiedSpan[];
         getEncodedSyntacticClassifications(fileName: string, span: TextSpan): Classifications;
         getEncodedSemanticClassifications(fileName: string, span: TextSpan): Classifications;
-        getCompletionsAtPosition(fileName: string, position: number): CompletionInfo;
-        getCompletionEntryDetails(fileName: string, position: number, name: string, options?: FormatCodeOptions | FormatCodeSettings, source?: string): CompletionEntryDetails;
-        getCompletionEntrySymbol(fileName: string, position: number, name: string, source?: string): Symbol;
+        getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined): CompletionInfo;
+        getCompletionEntryDetails(fileName: string, position: number, name: string, options: FormatCodeOptions | FormatCodeSettings | undefined, source: string | undefined): CompletionEntryDetails;
+        getCompletionEntrySymbol(fileName: string, position: number, name: string, source: string | undefined): Symbol;
         getQuickInfoAtPosition(fileName: string, position: number): QuickInfo;
         getNameOrDottedNameSpan(fileName: string, startPos: number, endPos: number): TextSpan;
         getBreakpointStatementAtPosition(fileName: string, position: number): TextSpan;
@@ -3924,6 +3942,7 @@ declare namespace ts {
         getRenameInfo(fileName: string, position: number): RenameInfo;
         findRenameLocations(fileName: string, position: number, findInStrings: boolean, findInComments: boolean): RenameLocation[];
         getDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
+        getDefinitionAndBoundSpan(fileName: string, position: number): DefinitionInfoAndBoundSpan;
         getTypeDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
         getImplementationAtPosition(fileName: string, position: number): ImplementationLocation[];
         getReferencesAtPosition(fileName: string, position: number): ReferenceEntry[];
@@ -3952,6 +3971,9 @@ declare namespace ts {
         getProgram(): Program;
         dispose(): void;
     }
+    interface GetCompletionsAtPositionOptions {
+        includeExternalModuleExports: boolean;
+    }
     interface ApplyCodeActionCommandResult {
         successMessage: string;
     }
@@ -4187,6 +4209,10 @@ declare namespace ts {
         containerKind: ScriptElementKind;
         containerName: string;
     }
+    interface DefinitionInfoAndBoundSpan {
+        definitions: ReadonlyArray<DefinitionInfo>;
+        textSpan: TextSpan;
+    }
     interface ReferencedSymbolDefinitionInfo extends DefinitionInfo {
         displayParts: SymbolDisplayPart[];
     }
@@ -4598,7 +4624,7 @@ declare namespace ts {
 }
 declare namespace ts {
     /** The version of the language service API */
-    const servicesVersion = "0.5";
+    const servicesVersion = "0.7";
     interface DisplayPartsSymbolWriter extends SymbolWriter {
         displayParts(): SymbolDisplayPart[];
     }
@@ -4752,17 +4778,17 @@ declare namespace ts.server {
         info(s: string): void;
         startGroup(): void;
         endGroup(): void;
-        msg(s: string, type?: Msg.Types): void;
+        msg(s: string, type?: Msg): void;
         getLogFileName(): string;
     }
+    enum Msg {
+        Err = "Err",
+        Info = "Info",
+        Perf = "Perf",
+    }
     namespace Msg {
-        type Err = "Err";
-        const Err: Err;
-        type Info = "Info";
-        const Info: Info;
-        type Perf = "Perf";
-        const Perf: Perf;
-        type Types = Err | Info | Perf;
+        /** @deprecated Only here for backwards-compatibility. Prefer just `Msg`. */
+        type Types = Msg;
     }
     function createInstallTypingsRequest(project: Project, typeAcquisition: TypeAcquisition, unresolvedImports: SortedReadonlyArray<string>, cachePath?: string): DiscoverTypings;
     namespace Errors {
@@ -4822,6 +4848,7 @@ declare namespace ts.server.protocol {
         CompileOnSaveEmitFile = "compileOnSaveEmitFile",
         Configure = "configure",
         Definition = "definition",
+        DefinitionAndBoundSpan = "definitionAndBoundSpan",
         Implementation = "implementation",
         Exit = "exit",
         Format = "format",
@@ -5341,12 +5368,19 @@ declare namespace ts.server.protocol {
          */
         file: string;
     }
+    interface DefinitionInfoAndBoundSpan {
+        definitions: ReadonlyArray<FileSpan>;
+        textSpan: TextSpan;
+    }
     /**
      * Definition response message.  Gives text range for definition.
      */
     interface DefinitionResponse extends Response {
         body?: FileSpan[];
     }
+    interface DefinitionInfoAndBoundSpanReponse extends Response {
+        body?: DefinitionInfoAndBoundSpan;
+    }
     /**
      * Definition response message.  Gives text range for definition.
      */
@@ -6015,6 +6049,11 @@ declare namespace ts.server.protocol {
          * Optional prefix to apply to possible completions.
          */
         prefix?: string;
+        /**
+         * If enabled, TypeScript will search through all external modules' exports and add them to the completions list.
+         * This affects lone identifier completions but not completions on the right hand side of `obj.`.
+         */
+        includeExternalModuleExports: boolean;
     }
     /**
      * Completions request; value of command field is "completions".
@@ -6922,6 +6961,9 @@ declare namespace ts.server {
         private convertToDiagnosticsWithLinePosition(diagnostics, scriptInfo);
         private getDiagnosticsWorker(args, isSemantic, selector, includeLinePosition);
         private getDefinition(args, simplifiedResult);
+        private getDefinitionAndBoundSpan(args, simplifiedResult);
+        private mapDefinitionInfo(definitions, project);
+        private toFileSpan(fileName, textSpan, project);
         private getTypeDefinition(args);
         private getImplementation(args, simplifiedResult);
         private getOccurrences(args);
@@ -6961,7 +7003,7 @@ declare namespace ts.server {
         private getFormattingEditsAfterKeystrokeFull(args);
         private getFormattingEditsAfterKeystroke(args);
         private getCompletions(args, simplifiedResult);
-        private getCompletionEntryDetails(args);
+        private getCompletionEntryDetails(args, simplifiedResult);
         private getCompileOnSaveAffectedFileList(args);
         private emitFile(args);
         private getSignatureHelpItems(args, simplifiedResult);
@@ -6971,10 +7013,10 @@ declare namespace ts.server {
         private reload(args, reqSeq);
         private saveToTmp(fileName, tempFileName);
         private closeClientFile(fileName);
-        private decorateNavigationBarItems(items, scriptInfo);
+        private mapLocationNavigationBarItems(items, scriptInfo);
         private getNavigationBarItems(args, simplifiedResult);
-        private decorateNavigationTree(tree, scriptInfo);
-        private decorateSpan(span, scriptInfo);
+        private toLocationNavigationTree(tree, scriptInfo);
+        private toLocationTextSpan(span, scriptInfo);
         private getNavigationTree(args, simplifiedResult);
         private getNavigateToItems(args, simplifiedResult);
         private getSupportedCodeFixes();
@@ -7023,7 +7065,7 @@ declare namespace ts.server {
         constructor(host: ServerHost, fileName: NormalizedPath, scriptKind: ScriptKind, hasMixedContent: boolean, path: Path);
         isScriptOpen(): boolean;
         open(newText: string): void;
-        close(): void;
+        close(fileExists?: boolean): void;
         getSnapshot(): IScriptSnapshot;
         getFormatCodeSettings(): FormatCodeSettings;
         attachToProject(project: Project): boolean;
@@ -7105,11 +7147,9 @@ declare namespace ts.server {
         create(createInfo: PluginCreateInfo): LanguageService;
         getExternalFiles?(proj: Project): string[];
     }
-    interface PluginModuleFactory {
-        (mod: {
-            typescript: typeof ts;
-        }): PluginModule;
-    }
+    type PluginModuleFactory = (mod: {
+        typescript: typeof ts;
+    }) => PluginModule;
     /**
      * The project root can be script info - if root is present,
      * or it could be just normalized path if root wasnt present on the host(only for non inferred project)
@@ -7379,9 +7419,7 @@ declare namespace ts.server {
         readonly dts: number;
     }
     type ProjectServiceEvent = ProjectsUpdatedInBackgroundEvent | ConfigFileDiagEvent | ProjectLanguageServiceStateEvent | ProjectInfoTelemetryEvent;
-    interface ProjectServiceEventHandler {
-        (event: ProjectServiceEvent): void;
-    }
+    type ProjectServiceEventHandler = (event: ProjectServiceEvent) => void;
     interface SafeList {
         [name: string]: {
             match: RegExp;
@@ -7453,6 +7491,10 @@ declare namespace ts.server {
          * Open files: with value being project root path, and key being Path of the file that is open
          */
         readonly openFiles: Map<NormalizedPath>;
+        /**
+         * Map of open files that are opened without complete path but have projectRoot as current directory
+         */
+        private readonly openFilesWithNonRootedDiskPath;
         private compilerOptionsForInferredProjects;
         private compilerOptionsForInferredProjectsPerProjectRoot;
         /**
@@ -7593,6 +7635,10 @@ declare namespace ts.server {
         private watchClosedScriptInfo(info);
         private stopWatchingScriptInfo(info);
         getOrCreateScriptInfoForNormalizedPath(fileName: NormalizedPath, openedByClient: boolean, fileContent?: string, scriptKind?: ScriptKind, hasMixedContent?: boolean, hostToQueryFileExistsOn?: DirectoryStructureHost): ScriptInfo;
+        private getOrCreateScriptInfoWorker(fileName, currentDirectory, openedByClient, fileContent?, scriptKind?, hasMixedContent?, hostToQueryFileExistsOn?);
+        /**
+         * This gets the script info for the normalized path. If the path is not rooted disk path then the open script info with project root context is preferred
+         */
         getScriptInfoForNormalizedPath(fileName: NormalizedPath): ScriptInfo;
         getScriptInfoForPath(fileName: Path): ScriptInfo;
         setHostConfiguration(args: protocol.ConfigureRequestArguments): void;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 2afef7d692c..98d7137ddeb 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -313,46 +313,49 @@ declare namespace ts {
         JsxSelfClosingElement = 250,
         JsxOpeningElement = 251,
         JsxClosingElement = 252,
-        JsxAttribute = 253,
-        JsxAttributes = 254,
-        JsxSpreadAttribute = 255,
-        JsxExpression = 256,
-        CaseClause = 257,
-        DefaultClause = 258,
-        HeritageClause = 259,
-        CatchClause = 260,
-        PropertyAssignment = 261,
-        ShorthandPropertyAssignment = 262,
-        SpreadAssignment = 263,
-        EnumMember = 264,
-        SourceFile = 265,
-        Bundle = 266,
-        JSDocTypeExpression = 267,
-        JSDocAllType = 268,
-        JSDocUnknownType = 269,
-        JSDocNullableType = 270,
-        JSDocNonNullableType = 271,
-        JSDocOptionalType = 272,
-        JSDocFunctionType = 273,
-        JSDocVariadicType = 274,
-        JSDocComment = 275,
-        JSDocTag = 276,
-        JSDocAugmentsTag = 277,
-        JSDocClassTag = 278,
-        JSDocParameterTag = 279,
-        JSDocReturnTag = 280,
-        JSDocTypeTag = 281,
-        JSDocTemplateTag = 282,
-        JSDocTypedefTag = 283,
-        JSDocPropertyTag = 284,
-        JSDocTypeLiteral = 285,
-        SyntaxList = 286,
-        NotEmittedStatement = 287,
-        PartiallyEmittedExpression = 288,
-        CommaListExpression = 289,
-        MergeDeclarationMarker = 290,
-        EndOfDeclarationMarker = 291,
-        Count = 292,
+        JsxFragment = 253,
+        JsxOpeningFragment = 254,
+        JsxClosingFragment = 255,
+        JsxAttribute = 256,
+        JsxAttributes = 257,
+        JsxSpreadAttribute = 258,
+        JsxExpression = 259,
+        CaseClause = 260,
+        DefaultClause = 261,
+        HeritageClause = 262,
+        CatchClause = 263,
+        PropertyAssignment = 264,
+        ShorthandPropertyAssignment = 265,
+        SpreadAssignment = 266,
+        EnumMember = 267,
+        SourceFile = 268,
+        Bundle = 269,
+        JSDocTypeExpression = 270,
+        JSDocAllType = 271,
+        JSDocUnknownType = 272,
+        JSDocNullableType = 273,
+        JSDocNonNullableType = 274,
+        JSDocOptionalType = 275,
+        JSDocFunctionType = 276,
+        JSDocVariadicType = 277,
+        JSDocComment = 278,
+        JSDocTypeLiteral = 279,
+        JSDocTag = 280,
+        JSDocAugmentsTag = 281,
+        JSDocClassTag = 282,
+        JSDocParameterTag = 283,
+        JSDocReturnTag = 284,
+        JSDocTypeTag = 285,
+        JSDocTemplateTag = 286,
+        JSDocTypedefTag = 287,
+        JSDocPropertyTag = 288,
+        SyntaxList = 289,
+        NotEmittedStatement = 290,
+        PartiallyEmittedExpression = 291,
+        CommaListExpression = 292,
+        MergeDeclarationMarker = 293,
+        EndOfDeclarationMarker = 294,
+        Count = 295,
         FirstAssignment = 58,
         LastAssignment = 70,
         FirstCompoundAssignment = 59,
@@ -378,10 +381,10 @@ declare namespace ts {
         FirstBinaryOperator = 27,
         LastBinaryOperator = 70,
         FirstNode = 143,
-        FirstJSDocNode = 267,
-        LastJSDocNode = 285,
-        FirstJSDocTagNode = 276,
-        LastJSDocTagNode = 285,
+        FirstJSDocNode = 270,
+        LastJSDocNode = 288,
+        FirstJSDocTagNode = 280,
+        LastJSDocTagNode = 288,
     }
     enum NodeFlags {
         None = 0,
@@ -408,7 +411,7 @@ declare namespace ts {
         BlockScoped = 3,
         ReachabilityCheckFlags = 384,
         ReachabilityAndEmitFlags = 1408,
-        ContextFlags = 2193408,
+        ContextFlags = 6387712,
         TypeExcludesFlags = 20480,
     }
     enum ModifierFlags {
@@ -1061,6 +1064,20 @@ declare namespace ts {
         tagName: JsxTagNameExpression;
         attributes: JsxAttributes;
     }
+    interface JsxFragment extends PrimaryExpression {
+        kind: SyntaxKind.JsxFragment;
+        openingFragment: JsxOpeningFragment;
+        children: NodeArray<JsxChild>;
+        closingFragment: JsxClosingFragment;
+    }
+    interface JsxOpeningFragment extends Expression {
+        kind: SyntaxKind.JsxOpeningFragment;
+        parent?: JsxFragment;
+    }
+    interface JsxClosingFragment extends Expression {
+        kind: SyntaxKind.JsxClosingFragment;
+        parent?: JsxFragment;
+    }
     interface JsxAttribute extends ObjectLiteralElement {
         kind: SyntaxKind.JsxAttribute;
         parent?: JsxAttributes;
@@ -1088,7 +1105,7 @@ declare namespace ts {
         containsOnlyWhiteSpaces: boolean;
         parent?: JsxElement;
     }
-    type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement;
+    type JsxChild = JsxText | JsxExpression | JsxElement | JsxSelfClosingElement | JsxFragment;
     interface Statement extends Node {
         _statementBrand: any;
     }
@@ -1592,8 +1609,8 @@ declare namespace ts {
     }
     interface ScriptReferenceHost {
         getCompilerOptions(): CompilerOptions;
-        getSourceFile(fileName: string): SourceFile;
-        getSourceFileByPath(path: Path): SourceFile;
+        getSourceFile(fileName: string): SourceFile | undefined;
+        getSourceFileByPath(path: Path): SourceFile | undefined;
         getCurrentDirectory(): string;
     }
     interface ParseConfigHost {
@@ -1606,9 +1623,7 @@ declare namespace ts {
         fileExists(path: string): boolean;
         readFile(path: string): string | undefined;
     }
-    interface WriteFileCallback {
-        (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>): void;
-    }
+    type WriteFileCallback = (fileName: string, data: string, writeByteOrderMark: boolean, onError: ((message: string) => void) | undefined, sourceFiles: ReadonlyArray<SourceFile>) => void;
     class OperationCanceledException {
     }
     interface CancellationToken {
@@ -2040,6 +2055,7 @@ declare namespace ts {
         ObjectLiteral = 128,
         EvolvingArray = 256,
         ObjectLiteralPatternWithComputedProperties = 512,
+        ContainsSpread = 1024,
         ClassOrInterface = 3,
     }
     interface ObjectType extends Type {
@@ -2740,9 +2756,7 @@ declare namespace ts {
     let sys: System;
 }
 declare namespace ts {
-    interface ErrorCallback {
-        (message: DiagnosticMessage, length: number): void;
-    }
+    type ErrorCallback = (message: DiagnosticMessage, length: number) => void;
     interface Scanner {
         getStartPos(): number;
         getToken(): SyntaxKind;
@@ -3056,6 +3070,9 @@ declare namespace ts {
     function isJsxSelfClosingElement(node: Node): node is JsxSelfClosingElement;
     function isJsxOpeningElement(node: Node): node is JsxOpeningElement;
     function isJsxClosingElement(node: Node): node is JsxClosingElement;
+    function isJsxFragment(node: Node): node is JsxFragment;
+    function isJsxOpeningFragment(node: Node): node is JsxOpeningFragment;
+    function isJsxClosingFragment(node: Node): node is JsxClosingFragment;
     function isJsxAttribute(node: Node): node is JsxAttribute;
     function isJsxAttributes(node: Node): node is JsxAttributes;
     function isJsxSpreadAttribute(node: Node): node is JsxSpreadAttribute;
@@ -3201,11 +3218,10 @@ declare namespace ts {
 }
 declare namespace ts {
     function createNodeArray<T extends Node>(elements?: ReadonlyArray<T>, hasTrailingComma?: boolean): NodeArray<T>;
-    function createLiteral(value: string): StringLiteral;
+    /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
+    function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: number): NumericLiteral;
     function createLiteral(value: boolean): BooleanLiteral;
-    /** Create a string literal whose source text is read from a source node during emit. */
-    function createLiteral(sourceNode: StringLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: string | number | boolean): PrimaryExpression;
     function createNumericLiteral(value: string): NumericLiteral;
     function createIdentifier(text: string): Identifier;
@@ -3447,6 +3463,8 @@ declare namespace ts {
     function updateJsxOpeningElement(node: JsxOpeningElement, tagName: JsxTagNameExpression, attributes: JsxAttributes): JsxOpeningElement;
     function createJsxClosingElement(tagName: JsxTagNameExpression): JsxClosingElement;
     function updateJsxClosingElement(node: JsxClosingElement, tagName: JsxTagNameExpression): JsxClosingElement;
+    function createJsxFragment(openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment): JsxFragment;
+    function updateJsxFragment(node: JsxFragment, openingFragment: JsxOpeningFragment, children: ReadonlyArray<JsxChild>, closingFragment: JsxClosingFragment): JsxFragment;
     function createJsxAttribute(name: Identifier, initializer: StringLiteral | JsxExpression): JsxAttribute;
     function updateJsxAttribute(node: JsxAttribute, name: Identifier, initializer: StringLiteral | JsxExpression): JsxAttribute;
     function createJsxAttributes(properties: ReadonlyArray<JsxAttributeLike>): JsxAttributes;
@@ -3794,7 +3812,7 @@ declare namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface Type {
@@ -3815,7 +3833,7 @@ declare namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface SourceFile {
@@ -3914,9 +3932,9 @@ declare namespace ts {
         getSemanticClassifications(fileName: string, span: TextSpan): ClassifiedSpan[];
         getEncodedSyntacticClassifications(fileName: string, span: TextSpan): Classifications;
         getEncodedSemanticClassifications(fileName: string, span: TextSpan): Classifications;
-        getCompletionsAtPosition(fileName: string, position: number): CompletionInfo;
-        getCompletionEntryDetails(fileName: string, position: number, name: string, options?: FormatCodeOptions | FormatCodeSettings, source?: string): CompletionEntryDetails;
-        getCompletionEntrySymbol(fileName: string, position: number, name: string, source?: string): Symbol;
+        getCompletionsAtPosition(fileName: string, position: number, options: GetCompletionsAtPositionOptions | undefined): CompletionInfo;
+        getCompletionEntryDetails(fileName: string, position: number, name: string, options: FormatCodeOptions | FormatCodeSettings | undefined, source: string | undefined): CompletionEntryDetails;
+        getCompletionEntrySymbol(fileName: string, position: number, name: string, source: string | undefined): Symbol;
         getQuickInfoAtPosition(fileName: string, position: number): QuickInfo;
         getNameOrDottedNameSpan(fileName: string, startPos: number, endPos: number): TextSpan;
         getBreakpointStatementAtPosition(fileName: string, position: number): TextSpan;
@@ -3924,6 +3942,7 @@ declare namespace ts {
         getRenameInfo(fileName: string, position: number): RenameInfo;
         findRenameLocations(fileName: string, position: number, findInStrings: boolean, findInComments: boolean): RenameLocation[];
         getDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
+        getDefinitionAndBoundSpan(fileName: string, position: number): DefinitionInfoAndBoundSpan;
         getTypeDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[];
         getImplementationAtPosition(fileName: string, position: number): ImplementationLocation[];
         getReferencesAtPosition(fileName: string, position: number): ReferenceEntry[];
@@ -3952,6 +3971,9 @@ declare namespace ts {
         getProgram(): Program;
         dispose(): void;
     }
+    interface GetCompletionsAtPositionOptions {
+        includeExternalModuleExports: boolean;
+    }
     interface ApplyCodeActionCommandResult {
         successMessage: string;
     }
@@ -4187,6 +4209,10 @@ declare namespace ts {
         containerKind: ScriptElementKind;
         containerName: string;
     }
+    interface DefinitionInfoAndBoundSpan {
+        definitions: ReadonlyArray<DefinitionInfo>;
+        textSpan: TextSpan;
+    }
     interface ReferencedSymbolDefinitionInfo extends DefinitionInfo {
         displayParts: SymbolDisplayPart[];
     }
@@ -4598,7 +4624,7 @@ declare namespace ts {
 }
 declare namespace ts {
     /** The version of the language service API */
-    const servicesVersion = "0.5";
+    const servicesVersion = "0.7";
     interface DisplayPartsSymbolWriter extends SymbolWriter {
         displayParts(): SymbolDisplayPart[];
     }
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt b/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
index 5a367a4122f..4d6fbd063ae 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
@@ -1,52 +1,49 @@
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(13,12): error TS2493: Tuple type '[string, number]' with length '2' cannot be assigned to tuple with length '3'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(14,12): error TS2460: Type 'StrNum' has no property '2'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,5): error TS2461: Type '{ 0: string; 1: number; }' is not an array type.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,12): error TS2460: Type '{ 0: string; 1: number; }' has no property '2'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(16,5): error TS2322: Type '[string, number]' is not assignable to type '[number, number, number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,12): error TS2493: Tuple type '[string, number]' with length '2' cannot be assigned to tuple with length '3'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(16,12): error TS2460: Type 'StrNum' has no property '2'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,5): error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,12): error TS2460: Type '{ 0: string; 1: number; length: 2; }' has no property '2'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(18,5): error TS2322: Type '[string, number]' is not assignable to type '[number, number, number]'.
   Property '2' is missing in type '[string, number]'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,5): error TS2322: Type 'StrNum' is not assignable to type '[number, number, number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(19,5): error TS2322: Type 'StrNum' is not assignable to type '[number, number, number]'.
   Property '2' is missing in type 'StrNum'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(18,5): error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number, number, number]'.
-  Property '2' is missing in type '{ 0: string; 1: number; }'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(19,5): error TS2322: Type '[string, number]' is not assignable to type '[string, number, number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(20,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number, number, number]'.
+  Property '2' is missing in type '{ 0: string; 1: number; length: 2; }'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(21,5): error TS2322: Type '[string, number]' is not assignable to type '[string, number, number]'.
   Property '2' is missing in type '[string, number]'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(20,5): error TS2322: Type 'StrNum' is not assignable to type '[string, number, number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(22,5): error TS2322: Type 'StrNum' is not assignable to type '[string, number, number]'.
   Property '2' is missing in type 'StrNum'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(21,5): error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[string, number, number]'.
-  Property '2' is missing in type '{ 0: string; 1: number; }'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(22,5): error TS2322: Type '[string, number]' is not assignable to type '[number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(23,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[string, number, number]'.
+  Property '2' is missing in type '{ 0: string; 1: number; length: 2; }'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(24,5): error TS2322: Type '[string, number]' is not assignable to type '[number]'.
   Types of property '0' are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(23,5): error TS2322: Type 'StrNum' is not assignable to type '[number]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(25,5): error TS2322: Type 'StrNum' is not assignable to type '[number]'.
   Types of property '0' are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(24,5): error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number]'.
-  Property 'length' is missing in type '{ 0: string; 1: number; }'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(25,5): error TS2322: Type '[string, number]' is not assignable to type '[string]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number' is not assignable to type '() => string'.
-      Type 'string | number' is not assignable to type 'string'.
-        Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(26,5): error TS2322: Type 'StrNum' is not assignable to type '[string]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number' is not assignable to type '() => string'.
-      Type 'string | number' is not assignable to type 'string'.
-        Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(27,5): error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[string]'.
-  Property 'length' is missing in type '{ 0: string; 1: number; }'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(28,5): error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(26,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number]'.
+  Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(27,5): error TS2322: Type '[string, number]' is not assignable to type '[string]'.
+  Types of property 'length' are incompatible.
+    Type '2' is not assignable to type '1'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(28,5): error TS2322: Type 'StrNum' is not assignable to type '[string]'.
+  Types of property 'length' are incompatible.
+    Type '2' is not assignable to type '1'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(29,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[string]'.
+  Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(29,5): error TS2322: Type 'StrNum' is not assignable to type '[number, string]'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(31,5): error TS2322: Type 'StrNum' is not assignable to type '[number, string]'.
   Types of property '0' are incompatible.
     Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number, string]'.
-  Property 'length' is missing in type '{ 0: string; 1: number; }'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(32,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number, string]'.
+  Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
 
 
 ==== tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts (19 errors) ====
     interface StrNum extends Array<string|number> {
         0: string;
         1: number;
+        length: 2;
     }
     
     var x: [string, number];
@@ -54,6 +51,7 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
     var z: {
         0: string;
         1: number;
+        length: 2;
     }
     
     var [a, b, c] = x;
@@ -64,9 +62,9 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
 !!! error TS2460: Type 'StrNum' has no property '2'.
     var [g, h, i] = z;
         ~~~~~~~~~
-!!! error TS2461: Type '{ 0: string; 1: number; }' is not an array type.
+!!! error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
                ~
-!!! error TS2460: Type '{ 0: string; 1: number; }' has no property '2'.
+!!! error TS2460: Type '{ 0: string; 1: number; length: 2; }' has no property '2'.
     var j1: [number, number, number] = x;
         ~~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[number, number, number]'.
@@ -77,8 +75,8 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
 !!! error TS2322:   Property '2' is missing in type 'StrNum'.
     var j3: [number, number, number] = z;
         ~~
-!!! error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number, number, number]'.
-!!! error TS2322:   Property '2' is missing in type '{ 0: string; 1: number; }'.
+!!! error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number, number, number]'.
+!!! error TS2322:   Property '2' is missing in type '{ 0: string; 1: number; length: 2; }'.
     var k1: [string, number, number] = x;
         ~~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[string, number, number]'.
@@ -89,8 +87,8 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
 !!! error TS2322:   Property '2' is missing in type 'StrNum'.
     var k3: [string, number, number] = z;
         ~~
-!!! error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[string, number, number]'.
-!!! error TS2322:   Property '2' is missing in type '{ 0: string; 1: number; }'.
+!!! error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[string, number, number]'.
+!!! error TS2322:   Property '2' is missing in type '{ 0: string; 1: number; length: 2; }'.
     var l1: [number] = x;
         ~~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[number]'.
@@ -103,26 +101,22 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
 !!! error TS2322:     Type 'string' is not assignable to type 'number'.
     var l3: [number] = z;
         ~~
-!!! error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number]'.
-!!! error TS2322:   Property 'length' is missing in type '{ 0: string; 1: number; }'.
+!!! error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number]'.
+!!! error TS2322:   Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
     var m1: [string] = x;
         ~~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[string]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number' is not assignable to type '() => string'.
-!!! error TS2322:       Type 'string | number' is not assignable to type 'string'.
-!!! error TS2322:         Type 'number' is not assignable to type 'string'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '2' is not assignable to type '1'.
     var m2: [string] = y;
         ~~
 !!! error TS2322: Type 'StrNum' is not assignable to type '[string]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number' is not assignable to type '() => string'.
-!!! error TS2322:       Type 'string | number' is not assignable to type 'string'.
-!!! error TS2322:         Type 'number' is not assignable to type 'string'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '2' is not assignable to type '1'.
     var m3: [string] = z;
         ~~
-!!! error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[string]'.
-!!! error TS2322:   Property 'length' is missing in type '{ 0: string; 1: number; }'.
+!!! error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[string]'.
+!!! error TS2322:   Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
     var n1: [number, string] = x;
         ~~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
@@ -134,8 +128,8 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(30,5): error
 !!! error TS2322:     Type 'string' is not assignable to type 'number'.
     var n3: [number, string] = z;
         ~~
-!!! error TS2322: Type '{ 0: string; 1: number; }' is not assignable to type '[number, string]'.
-!!! error TS2322:   Property 'length' is missing in type '{ 0: string; 1: number; }'.
+!!! error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number, string]'.
+!!! error TS2322:   Property 'push' is missing in type '{ 0: string; 1: number; length: 2; }'.
     var o1: [string, number] = x;
     var o2: [string, number] = y;
     var o3: [string, number] = y;
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.js b/tests/baselines/reference/arityAndOrderCompatibility01.js
index 2eb1bcf8bd8..bf7736a80c9 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.js
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.js
@@ -2,6 +2,7 @@
 interface StrNum extends Array<string|number> {
     0: string;
     1: number;
+    length: 2;
 }
 
 var x: [string, number];
@@ -9,6 +10,7 @@ var y: StrNum
 var z: {
     0: string;
     1: number;
+    length: 2;
 }
 
 var [a, b, c] = x;
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.symbols b/tests/baselines/reference/arityAndOrderCompatibility01.symbols
index c6ef08a845b..3a5d55dc1e6 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.symbols
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.symbols
@@ -5,109 +5,113 @@ interface StrNum extends Array<string|number> {
 
     0: string;
     1: number;
+    length: 2;
+>length : Symbol(StrNum.length, Decl(arityAndOrderCompatibility01.ts, 2, 14))
 }
 
 var x: [string, number];
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var y: StrNum
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 >StrNum : Symbol(StrNum, Decl(arityAndOrderCompatibility01.ts, 0, 0))
 
 var z: {
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
     0: string;
     1: number;
+    length: 2;
+>length : Symbol(length, Decl(arityAndOrderCompatibility01.ts, 10, 14))
 }
 
 var [a, b, c] = x;
->a : Symbol(a, Decl(arityAndOrderCompatibility01.ts, 12, 5))
->b : Symbol(b, Decl(arityAndOrderCompatibility01.ts, 12, 7))
->c : Symbol(c, Decl(arityAndOrderCompatibility01.ts, 12, 10))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>a : Symbol(a, Decl(arityAndOrderCompatibility01.ts, 14, 5))
+>b : Symbol(b, Decl(arityAndOrderCompatibility01.ts, 14, 7))
+>c : Symbol(c, Decl(arityAndOrderCompatibility01.ts, 14, 10))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var [d, e, f] = y;
->d : Symbol(d, Decl(arityAndOrderCompatibility01.ts, 13, 5))
->e : Symbol(e, Decl(arityAndOrderCompatibility01.ts, 13, 7))
->f : Symbol(f, Decl(arityAndOrderCompatibility01.ts, 13, 10))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>d : Symbol(d, Decl(arityAndOrderCompatibility01.ts, 15, 5))
+>e : Symbol(e, Decl(arityAndOrderCompatibility01.ts, 15, 7))
+>f : Symbol(f, Decl(arityAndOrderCompatibility01.ts, 15, 10))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var [g, h, i] = z;
->g : Symbol(g, Decl(arityAndOrderCompatibility01.ts, 14, 5))
->h : Symbol(h, Decl(arityAndOrderCompatibility01.ts, 14, 7))
->i : Symbol(i, Decl(arityAndOrderCompatibility01.ts, 14, 10))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>g : Symbol(g, Decl(arityAndOrderCompatibility01.ts, 16, 5))
+>h : Symbol(h, Decl(arityAndOrderCompatibility01.ts, 16, 7))
+>i : Symbol(i, Decl(arityAndOrderCompatibility01.ts, 16, 10))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var j1: [number, number, number] = x;
->j1 : Symbol(j1, Decl(arityAndOrderCompatibility01.ts, 15, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>j1 : Symbol(j1, Decl(arityAndOrderCompatibility01.ts, 17, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var j2: [number, number, number] = y;
->j2 : Symbol(j2, Decl(arityAndOrderCompatibility01.ts, 16, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>j2 : Symbol(j2, Decl(arityAndOrderCompatibility01.ts, 18, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var j3: [number, number, number] = z;
->j3 : Symbol(j3, Decl(arityAndOrderCompatibility01.ts, 17, 3))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>j3 : Symbol(j3, Decl(arityAndOrderCompatibility01.ts, 19, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var k1: [string, number, number] = x;
->k1 : Symbol(k1, Decl(arityAndOrderCompatibility01.ts, 18, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>k1 : Symbol(k1, Decl(arityAndOrderCompatibility01.ts, 20, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var k2: [string, number, number] = y;
->k2 : Symbol(k2, Decl(arityAndOrderCompatibility01.ts, 19, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>k2 : Symbol(k2, Decl(arityAndOrderCompatibility01.ts, 21, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var k3: [string, number, number] = z;
->k3 : Symbol(k3, Decl(arityAndOrderCompatibility01.ts, 20, 3))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>k3 : Symbol(k3, Decl(arityAndOrderCompatibility01.ts, 22, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var l1: [number] = x;
->l1 : Symbol(l1, Decl(arityAndOrderCompatibility01.ts, 21, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>l1 : Symbol(l1, Decl(arityAndOrderCompatibility01.ts, 23, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var l2: [number] = y;
->l2 : Symbol(l2, Decl(arityAndOrderCompatibility01.ts, 22, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>l2 : Symbol(l2, Decl(arityAndOrderCompatibility01.ts, 24, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var l3: [number] = z;
->l3 : Symbol(l3, Decl(arityAndOrderCompatibility01.ts, 23, 3))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>l3 : Symbol(l3, Decl(arityAndOrderCompatibility01.ts, 25, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var m1: [string] = x;
->m1 : Symbol(m1, Decl(arityAndOrderCompatibility01.ts, 24, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>m1 : Symbol(m1, Decl(arityAndOrderCompatibility01.ts, 26, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var m2: [string] = y;
->m2 : Symbol(m2, Decl(arityAndOrderCompatibility01.ts, 25, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>m2 : Symbol(m2, Decl(arityAndOrderCompatibility01.ts, 27, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var m3: [string] = z;
->m3 : Symbol(m3, Decl(arityAndOrderCompatibility01.ts, 26, 3))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>m3 : Symbol(m3, Decl(arityAndOrderCompatibility01.ts, 28, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var n1: [number, string] = x;
->n1 : Symbol(n1, Decl(arityAndOrderCompatibility01.ts, 27, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>n1 : Symbol(n1, Decl(arityAndOrderCompatibility01.ts, 29, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var n2: [number, string] = y;
->n2 : Symbol(n2, Decl(arityAndOrderCompatibility01.ts, 28, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>n2 : Symbol(n2, Decl(arityAndOrderCompatibility01.ts, 30, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var n3: [number, string] = z;
->n3 : Symbol(n3, Decl(arityAndOrderCompatibility01.ts, 29, 3))
->z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 7, 3))
+>n3 : Symbol(n3, Decl(arityAndOrderCompatibility01.ts, 31, 3))
+>z : Symbol(z, Decl(arityAndOrderCompatibility01.ts, 8, 3))
 
 var o1: [string, number] = x;
->o1 : Symbol(o1, Decl(arityAndOrderCompatibility01.ts, 30, 3))
->x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 5, 3))
+>o1 : Symbol(o1, Decl(arityAndOrderCompatibility01.ts, 32, 3))
+>x : Symbol(x, Decl(arityAndOrderCompatibility01.ts, 6, 3))
 
 var o2: [string, number] = y;
->o2 : Symbol(o2, Decl(arityAndOrderCompatibility01.ts, 31, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>o2 : Symbol(o2, Decl(arityAndOrderCompatibility01.ts, 33, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
 var o3: [string, number] = y;
->o3 : Symbol(o3, Decl(arityAndOrderCompatibility01.ts, 32, 3))
->y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 6, 3))
+>o3 : Symbol(o3, Decl(arityAndOrderCompatibility01.ts, 34, 3))
+>y : Symbol(y, Decl(arityAndOrderCompatibility01.ts, 7, 3))
 
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.types b/tests/baselines/reference/arityAndOrderCompatibility01.types
index 934c5c6966d..80e91fbd2e7 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.types
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.types
@@ -5,6 +5,8 @@ interface StrNum extends Array<string|number> {
 
     0: string;
     1: number;
+    length: 2;
+>length : 2
 }
 
 var x: [string, number];
@@ -15,10 +17,12 @@ var y: StrNum
 >StrNum : StrNum
 
 var z: {
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
     0: string;
     1: number;
+    length: 2;
+>length : 2
 }
 
 var [a, b, c] = x;
@@ -37,7 +41,7 @@ var [g, h, i] = z;
 >g : string
 >h : number
 >i : any
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var j1: [number, number, number] = x;
 >j1 : [number, number, number]
@@ -49,7 +53,7 @@ var j2: [number, number, number] = y;
 
 var j3: [number, number, number] = z;
 >j3 : [number, number, number]
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var k1: [string, number, number] = x;
 >k1 : [string, number, number]
@@ -61,7 +65,7 @@ var k2: [string, number, number] = y;
 
 var k3: [string, number, number] = z;
 >k3 : [string, number, number]
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var l1: [number] = x;
 >l1 : [number]
@@ -73,7 +77,7 @@ var l2: [number] = y;
 
 var l3: [number] = z;
 >l3 : [number]
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var m1: [string] = x;
 >m1 : [string]
@@ -85,7 +89,7 @@ var m2: [string] = y;
 
 var m3: [string] = z;
 >m3 : [string]
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var n1: [number, string] = x;
 >n1 : [number, string]
@@ -97,7 +101,7 @@ var n2: [number, string] = y;
 
 var n3: [number, string] = z;
 >n3 : [number, string]
->z : { 0: string; 1: number; }
+>z : { 0: string; 1: number; length: 2; }
 
 var o1: [string, number] = x;
 >o1 : [string, number]
diff --git a/tests/baselines/reference/arrayLiteralExpressionContextualTyping.errors.txt b/tests/baselines/reference/arrayLiteralExpressionContextualTyping.errors.txt
index 3e9777aea7c..8cb36b113a7 100644
--- a/tests/baselines/reference/arrayLiteralExpressionContextualTyping.errors.txt
+++ b/tests/baselines/reference/arrayLiteralExpressionContextualTyping.errors.txt
@@ -1,27 +1,37 @@
+tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(6,5): error TS2322: Type '[number, number, number, number]' is not assignable to type '[number, number, number]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
+tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(7,5): error TS2322: Type '[number, number, number, string]' is not assignable to type '[string | number, string | number, string | number]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
 tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(8,5): error TS2322: Type '[number, number, number, string]' is not assignable to type '[number, number, number]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number' is not assignable to type '() => number'.
-      Type 'string | number' is not assignable to type 'number'.
-        Type 'string' is not assignable to type 'number'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
 tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(14,5): error TS2322: Type 'number[]' is not assignable to type '[number, number, number]'.
   Property '0' is missing in type 'number[]'.
 
 
-==== tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts (2 errors) ====
+==== tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts (4 errors) ====
     // In a contextually typed array literal expression containing no spread elements, an element expression at index N is contextually typed by
     //      the type of the property with the numeric name N in the contextual type, if any, or otherwise
     //      the numeric index type of the contextual type, if any.
     var array = [1, 2, 3];
     var array1 = [true, 2, 3];  // Contextual type by the numeric index type of the contextual type
     var tup: [number, number, number] = [1, 2, 3, 4];
+        ~~~
+!!! error TS2322: Type '[number, number, number, number]' is not assignable to type '[number, number, number]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '4' is not assignable to type '3'.
     var tup1: [number|string, number|string, number|string] = [1, 2, 3, "string"];
+        ~~~~
+!!! error TS2322: Type '[number, number, number, string]' is not assignable to type '[string | number, string | number, string | number]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '4' is not assignable to type '3'.
     var tup2: [number, number, number] = [1, 2, 3, "string"];  // Error
         ~~~~
 !!! error TS2322: Type '[number, number, number, string]' is not assignable to type '[number, number, number]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number' is not assignable to type '() => number'.
-!!! error TS2322:       Type 'string | number' is not assignable to type 'number'.
-!!! error TS2322:         Type 'string' is not assignable to type 'number'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '4' is not assignable to type '3'.
     
     // In a contextually typed array literal expression containing one or more spread elements,
     // an element expression at index N is contextually typed by the numeric index type of the contextual type, if any.
diff --git a/tests/baselines/reference/arrayLiterals3.errors.txt b/tests/baselines/reference/arrayLiterals3.errors.txt
index 3ebf4174f51..8c36d7d59c1 100644
--- a/tests/baselines/reference/arrayLiterals3.errors.txt
+++ b/tests/baselines/reference/arrayLiterals3.errors.txt
@@ -3,10 +3,8 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(10,5): error
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(11,5): error TS2322: Type '["string", number, boolean]' is not assignable to type '[boolean, string, number]'.
   Type '"string"' is not assignable to type 'boolean'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(17,5): error TS2322: Type '[number, number, string, boolean]' is not assignable to type '[number, number]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number | boolean' is not assignable to type '() => number'.
-      Type 'string | number | boolean' is not assignable to type 'number'.
-        Type 'string' is not assignable to type 'number'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '2'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(32,5): error TS2322: Type '(number[] | string[])[]' is not assignable to type 'tup'.
   Property '0' is missing in type '(number[] | string[])[]'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(33,5): error TS2322: Type 'number[]' is not assignable to type '[number, number, number]'.
@@ -46,10 +44,8 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(34,5): error
     var [b1, b2]: [number, number] = [1, 2, "string", true];
         ~~~~~~~~
 !!! error TS2322: Type '[number, number, string, boolean]' is not assignable to type '[number, number]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number | boolean' is not assignable to type '() => number'.
-!!! error TS2322:       Type 'string | number | boolean' is not assignable to type 'number'.
-!!! error TS2322:         Type 'string' is not assignable to type 'number'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '4' is not assignable to type '2'.
     
     // The resulting type an array literal expression is determined as follows:
     //      - the resulting type is an array type with an element type that is the union of the types of the
diff --git a/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.types b/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.types
index 9cdbe0a0a61..75013cdef09 100644
--- a/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.types
+++ b/tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.types
@@ -55,8 +55,8 @@ var myList: MyList<number>;
 >MyList : MyList<T>
 
 var xs = [list, myList]; // {}[]
->xs : List<number>[]
->[list, myList] : List<number>[]
+>xs : (List<number> | MyList<number>)[]
+>[list, myList] : (List<number> | MyList<number>)[]
 >list : List<number>
 >myList : MyList<number>
 
diff --git a/tests/baselines/reference/asyncFunctionDeclaration10_es2017.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration10_es2017.errors.txt
index 33cd913a2eb..12f9974484b 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration10_es2017.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration10_es2017.errors.txt
@@ -4,11 +4,12 @@ tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclarati
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,33): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,38): error TS1005: ';' expected.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,39): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,41): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,49): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts(1,53): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts (8 errors) ====
+==== tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration10_es2017.ts (9 errors) ====
     async function foo(a = await => await): Promise<void> {
                        ~~~~~~~~~
 !!! error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
@@ -22,8 +23,11 @@ tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclarati
 !!! error TS1005: ';' expected.
                                           ~
 !!! error TS1128: Declaration or statement expected.
+                                            ~~~~~~~~~~~~~~~
                                                     ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                                         ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncFunctionDeclaration10_es5.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration10_es5.errors.txt
index b974eacd882..155119784ba 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration10_es5.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration10_es5.errors.txt
@@ -4,11 +4,12 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,33): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,38): error TS1005: ';' expected.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,39): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,41): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,49): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts(1,53): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts (8 errors) ====
+==== tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration10_es5.ts (9 errors) ====
     async function foo(a = await => await): Promise<void> {
                        ~~~~~~~~~
 !!! error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
@@ -22,8 +23,11 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
 !!! error TS1005: ';' expected.
                                           ~
 !!! error TS1128: Declaration or statement expected.
+                                            ~~~~~~~~~~~~~~~
                                                     ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                                         ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncFunctionDeclaration10_es6.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration10_es6.errors.txt
index b752ec94a45..7f5266f931e 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration10_es6.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration10_es6.errors.txt
@@ -4,11 +4,12 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration1
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,33): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,38): error TS1005: ';' expected.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,39): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,41): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,49): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts(1,53): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts (8 errors) ====
+==== tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration10_es6.ts (9 errors) ====
     async function foo(a = await => await): Promise<void> {
                        ~~~~~~~~~
 !!! error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
@@ -22,8 +23,11 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration1
 !!! error TS1005: ';' expected.
                                           ~
 !!! error TS1128: Declaration or statement expected.
+                                            ~~~~~~~~~~~~~~~
                                                     ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                                         ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncFunctionDeclaration5_es2017.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration5_es2017.errors.txt
index 1fc74dfa0a2..2d110f68127 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration5_es2017.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration5_es2017.errors.txt
@@ -2,11 +2,12 @@ tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclarati
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,20): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,25): error TS1005: ';' expected.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,26): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,28): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,36): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts(1,40): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts (6 errors) ====
+==== tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclaration5_es2017.ts (7 errors) ====
     async function foo(await): Promise<void> {
                        ~~~~~
 !!! error TS1138: Parameter declaration expected.
@@ -16,8 +17,11 @@ tests/cases/conformance/async/es2017/functionDeclarations/asyncFunctionDeclarati
 !!! error TS1005: ';' expected.
                              ~
 !!! error TS1128: Declaration or statement expected.
+                               ~~~~~~~~~~~~~~~
                                        ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                            ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncFunctionDeclaration5_es5.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration5_es5.errors.txt
index 48299773218..6607ec7ff5c 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration5_es5.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration5_es5.errors.txt
@@ -2,11 +2,12 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,20): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,25): error TS1005: ';' expected.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,26): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,28): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,36): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts(1,40): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts (6 errors) ====
+==== tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5_es5.ts (7 errors) ====
     async function foo(await): Promise<void> {
                        ~~~~~
 !!! error TS1138: Parameter declaration expected.
@@ -16,8 +17,11 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration5
 !!! error TS1005: ';' expected.
                              ~
 !!! error TS1128: Declaration or statement expected.
+                               ~~~~~~~~~~~~~~~
                                        ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                            ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncFunctionDeclaration5_es6.errors.txt b/tests/baselines/reference/asyncFunctionDeclaration5_es6.errors.txt
index 2e907d13400..ccddf6d5c04 100644
--- a/tests/baselines/reference/asyncFunctionDeclaration5_es6.errors.txt
+++ b/tests/baselines/reference/asyncFunctionDeclaration5_es6.errors.txt
@@ -2,11 +2,12 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,20): error TS2304: Cannot find name 'await'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,25): error TS1005: ';' expected.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,26): error TS1128: Declaration or statement expected.
+tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,28): error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,36): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts(1,40): error TS1109: Expression expected.
 
 
-==== tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts (6 errors) ====
+==== tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5_es6.ts (7 errors) ====
     async function foo(await): Promise<void> {
                        ~~~~~
 !!! error TS1138: Parameter declaration expected.
@@ -16,8 +17,11 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration5
 !!! error TS1005: ';' expected.
                              ~
 !!! error TS1128: Declaration or statement expected.
+                               ~~~~~~~~~~~~~~~
                                        ~~~~
 !!! error TS2532: Object is possibly 'undefined'.
                                            ~
 !!! error TS1109: Expression expected.
-    }
\ No newline at end of file
+    }
+    ~
+!!! error TS2365: Operator '>' cannot be applied to types 'boolean' and '{}'.
\ No newline at end of file
diff --git a/tests/baselines/reference/augmentedTypesClass3.js b/tests/baselines/reference/augmentedTypesClass3.js
index d2ad63161b5..045109f8587 100644
--- a/tests/baselines/reference/augmentedTypesClass3.js
+++ b/tests/baselines/reference/augmentedTypesClass3.js
@@ -46,4 +46,4 @@ var c5c = /** @class */ (function () {
     c5c.prototype.foo = function () { };
     return c5c;
 }());
-//import c5c = require(''); 
+//import c5c = require('');
diff --git a/tests/baselines/reference/augmentedTypesEnum.js b/tests/baselines/reference/augmentedTypesEnum.js
index ff0ad93f817..edd4a92d767 100644
--- a/tests/baselines/reference/augmentedTypesEnum.js
+++ b/tests/baselines/reference/augmentedTypesEnum.js
@@ -100,4 +100,4 @@ var e6b;
 })(e6b || (e6b = {})); // should be error
 // enum then import, messes with error reporting
 //enum e7 { One }
-//import e7 = require(''); // should be error 
+//import e7 = require(''); // should be error
diff --git a/tests/baselines/reference/augmentedTypesEnum2.js b/tests/baselines/reference/augmentedTypesEnum2.js
index 66fc96b62a0..0e6e70df263 100644
--- a/tests/baselines/reference/augmentedTypesEnum2.js
+++ b/tests/baselines/reference/augmentedTypesEnum2.js
@@ -41,4 +41,4 @@ var e2 = /** @class */ (function () {
     return e2;
 }());
 //enum then enum - covered
-//enum then import - covered 
+//enum then import - covered
diff --git a/tests/baselines/reference/augmentedTypesFunction.js b/tests/baselines/reference/augmentedTypesFunction.js
index 3c6066e5bb4..a2dd4a664a3 100644
--- a/tests/baselines/reference/augmentedTypesFunction.js
+++ b/tests/baselines/reference/augmentedTypesFunction.js
@@ -79,4 +79,4 @@ function y5b() { }
 function y5c() { }
 // function then import, messes with other errors
 //function y6() { }
-//import y6 = require(''); 
+//import y6 = require('');
diff --git a/tests/baselines/reference/augmentedTypesInterface.js b/tests/baselines/reference/augmentedTypesInterface.js
index b74da5bbfee..0409e157584 100644
--- a/tests/baselines/reference/augmentedTypesInterface.js
+++ b/tests/baselines/reference/augmentedTypesInterface.js
@@ -48,4 +48,4 @@ var i3;
     i3[i3["One"] = 0] = "One";
 })(i3 || (i3 = {}));
 ; // error
-//import i4 = require('');  // error 
+//import i4 = require('');  // error
diff --git a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.types b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.types
index f3ea48e637b..9a10984a522 100644
--- a/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.types
+++ b/tests/baselines/reference/bestCommonTypeOfConditionalExpressions.types
@@ -47,7 +47,7 @@ var r = true ? 1 : 2;
 
 var r3 = true ? 1 : {};
 >r3 : {}
->true ? 1 : {} : {}
+>true ? 1 : {} : 1 | {}
 >true : true
 >1 : 1
 >{} : {}
diff --git a/tests/baselines/reference/capturedParametersInInitializers2.js b/tests/baselines/reference/capturedParametersInInitializers2.js
index 2e833cac003..8982862af4f 100644
--- a/tests/baselines/reference/capturedParametersInInitializers2.js
+++ b/tests/baselines/reference/capturedParametersInInitializers2.js
@@ -19,11 +19,14 @@ function foo(y, x) {
     var _a;
 }
 function foo2(y, x) {
-    if (y === void 0) { y = /** @class */ (function () {
-        function class_2() {
-            this[x] = x;
-        }
-        return class_2;
-    }()); }
+    if (y === void 0) { y = (_a = /** @class */ (function () {
+            function class_2() {
+                this[_b] = x;
+            }
+            return class_2;
+        }()),
+        _b = x,
+        _a); }
     if (x === void 0) { x = 1; }
+    var _b, _a;
 }
diff --git a/tests/baselines/reference/castingTuple.errors.txt b/tests/baselines/reference/castingTuple.errors.txt
index eb6aac5f463..a17f8c2b082 100644
--- a/tests/baselines/reference/castingTuple.errors.txt
+++ b/tests/baselines/reference/castingTuple.errors.txt
@@ -1,13 +1,21 @@
-tests/cases/conformance/types/tuple/castingTuple.ts(28,10): error TS2352: Type '[number, string]' cannot be converted to type '[number, number]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(13,23): error TS2352: Type '[number, string]' cannot be converted to type '[number, string, boolean]'.
+  Property '2' is missing in type '[number, string]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(14,15): error TS2352: Type '[number, string, boolean]' cannot be converted to type '[number, string]'.
+  Types of property 'length' are incompatible.
+    Type '3' is not comparable to type '2'.
+tests/cases/conformance/types/tuple/castingTuple.ts(15,14): error TS2352: Type '[number, string]' cannot be converted to type '[number, string, boolean]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(18,21): error TS2352: Type '[C, D]' cannot be converted to type '[C, D, A]'.
+  Property '2' is missing in type '[C, D]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(30,10): error TS2352: Type '[number, string]' cannot be converted to type '[number, number]'.
   Type 'string' is not comparable to type 'number'.
-tests/cases/conformance/types/tuple/castingTuple.ts(29,10): error TS2352: Type '[C, D]' cannot be converted to type '[A, I]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(31,10): error TS2352: Type '[C, D]' cannot be converted to type '[A, I]'.
   Type 'C' is not comparable to type 'A'.
     Property 'a' is missing in type 'C'.
-tests/cases/conformance/types/tuple/castingTuple.ts(30,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'array1' has type '{}[]' at tests/cases/conformance/types/tuple/castingTuple.ts 20:4, but here has type 'number[]'.
-tests/cases/conformance/types/tuple/castingTuple.ts(31,1): error TS2304: Cannot find name 't4'.
+tests/cases/conformance/types/tuple/castingTuple.ts(32,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'array1' has type '{}[]' at tests/cases/conformance/types/tuple/castingTuple.ts 22:4, but here has type 'number[]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(33,1): error TS2304: Cannot find name 't4'.
 
 
-==== tests/cases/conformance/types/tuple/castingTuple.ts (4 errors) ====
+==== tests/cases/conformance/types/tuple/castingTuple.ts (8 errors) ====
     interface I { }
     class A { a = 10; }
     class C implements I { c };
@@ -21,9 +29,23 @@ tests/cases/conformance/types/tuple/castingTuple.ts(31,1): error TS2304: Cannot
     var numStrTuple: [number, string] = [5, "foo"];
     var emptyObjTuple = <[{}, {}]>numStrTuple;
     var numStrBoolTuple = <[number, string, boolean]>numStrTuple;
+                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type '[number, string]' cannot be converted to type '[number, string, boolean]'.
+!!! error TS2352:   Property '2' is missing in type '[number, string]'.
+    var shorter = numStrBoolTuple as [number, string]
+                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type '[number, string, boolean]' cannot be converted to type '[number, string]'.
+!!! error TS2352:   Types of property 'length' are incompatible.
+!!! error TS2352:     Type '3' is not comparable to type '2'.
+    var longer = numStrTuple as [number, string, boolean]
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type '[number, string]' cannot be converted to type '[number, string, boolean]'.
     var classCDTuple: [C, D] = [new C(), new D()];
     var interfaceIITuple = <[I, I]>classCDTuple;
     var classCDATuple = <[C, D, A]>classCDTuple;
+                        ~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2352: Type '[C, D]' cannot be converted to type '[C, D, A]'.
+!!! error TS2352:   Property '2' is missing in type '[C, D]'.
     var eleFromCDA1 = classCDATuple[2]; // A
     var eleFromCDA2 = classCDATuple[5]; // C | D | A
     var t10: [E1, E2] = [E1.one, E2.one];
@@ -46,7 +68,7 @@ tests/cases/conformance/types/tuple/castingTuple.ts(31,1): error TS2304: Cannot
 !!! error TS2352:     Property 'a' is missing in type 'C'.
     var array1 = <number[]>numStrTuple;
         ~~~~~~
-!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'array1' has type '{}[]' at tests/cases/conformance/types/tuple/castingTuple.ts 20:4, but here has type 'number[]'.
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'array1' has type '{}[]' at tests/cases/conformance/types/tuple/castingTuple.ts 22:4, but here has type 'number[]'.
     t4[2] = 10;
     ~~
 !!! error TS2304: Cannot find name 't4'.
diff --git a/tests/baselines/reference/castingTuple.js b/tests/baselines/reference/castingTuple.js
index 3744d40d8a5..a94246a19b8 100644
--- a/tests/baselines/reference/castingTuple.js
+++ b/tests/baselines/reference/castingTuple.js
@@ -12,6 +12,8 @@ enum E2 { one }
 var numStrTuple: [number, string] = [5, "foo"];
 var emptyObjTuple = <[{}, {}]>numStrTuple;
 var numStrBoolTuple = <[number, string, boolean]>numStrTuple;
+var shorter = numStrBoolTuple as [number, string]
+var longer = numStrTuple as [number, string, boolean]
 var classCDTuple: [C, D] = [new C(), new D()];
 var interfaceIITuple = <[I, I]>classCDTuple;
 var classCDATuple = <[C, D, A]>classCDTuple;
@@ -89,6 +91,8 @@ var E2;
 var numStrTuple = [5, "foo"];
 var emptyObjTuple = numStrTuple;
 var numStrBoolTuple = numStrTuple;
+var shorter = numStrBoolTuple;
+var longer = numStrTuple;
 var classCDTuple = [new C(), new D()];
 var interfaceIITuple = classCDTuple;
 var classCDATuple = classCDTuple;
diff --git a/tests/baselines/reference/castingTuple.symbols b/tests/baselines/reference/castingTuple.symbols
index 61edfb4b376..3cf5face2a6 100644
--- a/tests/baselines/reference/castingTuple.symbols
+++ b/tests/baselines/reference/castingTuple.symbols
@@ -46,37 +46,45 @@ var numStrBoolTuple = <[number, string, boolean]>numStrTuple;
 >numStrBoolTuple : Symbol(numStrBoolTuple, Decl(castingTuple.ts, 12, 3))
 >numStrTuple : Symbol(numStrTuple, Decl(castingTuple.ts, 10, 3))
 
+var shorter = numStrBoolTuple as [number, string]
+>shorter : Symbol(shorter, Decl(castingTuple.ts, 13, 3))
+>numStrBoolTuple : Symbol(numStrBoolTuple, Decl(castingTuple.ts, 12, 3))
+
+var longer = numStrTuple as [number, string, boolean]
+>longer : Symbol(longer, Decl(castingTuple.ts, 14, 3))
+>numStrTuple : Symbol(numStrTuple, Decl(castingTuple.ts, 10, 3))
+
 var classCDTuple: [C, D] = [new C(), new D()];
->classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 13, 3))
+>classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 15, 3))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >D : Symbol(D, Decl(castingTuple.ts, 2, 27))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >D : Symbol(D, Decl(castingTuple.ts, 2, 27))
 
 var interfaceIITuple = <[I, I]>classCDTuple;
->interfaceIITuple : Symbol(interfaceIITuple, Decl(castingTuple.ts, 14, 3))
+>interfaceIITuple : Symbol(interfaceIITuple, Decl(castingTuple.ts, 16, 3))
 >I : Symbol(I, Decl(castingTuple.ts, 0, 0))
 >I : Symbol(I, Decl(castingTuple.ts, 0, 0))
->classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 13, 3))
+>classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 15, 3))
 
 var classCDATuple = <[C, D, A]>classCDTuple;
->classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 15, 3))
+>classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 17, 3))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >D : Symbol(D, Decl(castingTuple.ts, 2, 27))
 >A : Symbol(A, Decl(castingTuple.ts, 0, 15))
->classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 13, 3))
+>classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 15, 3))
 
 var eleFromCDA1 = classCDATuple[2]; // A
->eleFromCDA1 : Symbol(eleFromCDA1, Decl(castingTuple.ts, 16, 3))
->classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 15, 3))
+>eleFromCDA1 : Symbol(eleFromCDA1, Decl(castingTuple.ts, 18, 3))
+>classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 17, 3))
 >2 : Symbol(2)
 
 var eleFromCDA2 = classCDATuple[5]; // C | D | A
->eleFromCDA2 : Symbol(eleFromCDA2, Decl(castingTuple.ts, 17, 3))
->classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 15, 3))
+>eleFromCDA2 : Symbol(eleFromCDA2, Decl(castingTuple.ts, 19, 3))
+>classCDATuple : Symbol(classCDATuple, Decl(castingTuple.ts, 17, 3))
 
 var t10: [E1, E2] = [E1.one, E2.one];
->t10 : Symbol(t10, Decl(castingTuple.ts, 18, 3))
+>t10 : Symbol(t10, Decl(castingTuple.ts, 20, 3))
 >E1 : Symbol(E1, Decl(castingTuple.ts, 5, 24))
 >E2 : Symbol(E2, Decl(castingTuple.ts, 6, 15))
 >E1.one : Symbol(E1.one, Decl(castingTuple.ts, 6, 9))
@@ -87,45 +95,45 @@ var t10: [E1, E2] = [E1.one, E2.one];
 >one : Symbol(E2.one, Decl(castingTuple.ts, 7, 9))
 
 var t11 = <[number, number]>t10;
->t11 : Symbol(t11, Decl(castingTuple.ts, 19, 3))
->t10 : Symbol(t10, Decl(castingTuple.ts, 18, 3))
+>t11 : Symbol(t11, Decl(castingTuple.ts, 21, 3))
+>t10 : Symbol(t10, Decl(castingTuple.ts, 20, 3))
 
 var array1 = <{}[]>emptyObjTuple;
->array1 : Symbol(array1, Decl(castingTuple.ts, 20, 3), Decl(castingTuple.ts, 29, 3))
+>array1 : Symbol(array1, Decl(castingTuple.ts, 22, 3), Decl(castingTuple.ts, 31, 3))
 >emptyObjTuple : Symbol(emptyObjTuple, Decl(castingTuple.ts, 11, 3))
 
 var unionTuple: [C, string | number] = [new C(), "foo"];
->unionTuple : Symbol(unionTuple, Decl(castingTuple.ts, 21, 3))
+>unionTuple : Symbol(unionTuple, Decl(castingTuple.ts, 23, 3))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 
 var unionTuple2: [C, string | number, D] = [new C(), "foo", new D()];
->unionTuple2 : Symbol(unionTuple2, Decl(castingTuple.ts, 22, 3))
+>unionTuple2 : Symbol(unionTuple2, Decl(castingTuple.ts, 24, 3))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >D : Symbol(D, Decl(castingTuple.ts, 2, 27))
 >C : Symbol(C, Decl(castingTuple.ts, 1, 19))
 >D : Symbol(D, Decl(castingTuple.ts, 2, 27))
 
 var unionTuple3: [number, string| number] = [10, "foo"]; 
->unionTuple3 : Symbol(unionTuple3, Decl(castingTuple.ts, 23, 3))
+>unionTuple3 : Symbol(unionTuple3, Decl(castingTuple.ts, 25, 3))
 
 var unionTuple4 = <[number, number]>unionTuple3; 
->unionTuple4 : Symbol(unionTuple4, Decl(castingTuple.ts, 24, 3))
->unionTuple3 : Symbol(unionTuple3, Decl(castingTuple.ts, 23, 3))
+>unionTuple4 : Symbol(unionTuple4, Decl(castingTuple.ts, 26, 3))
+>unionTuple3 : Symbol(unionTuple3, Decl(castingTuple.ts, 25, 3))
 
 // error
 var t3 = <[number, number]>numStrTuple;
->t3 : Symbol(t3, Decl(castingTuple.ts, 27, 3))
+>t3 : Symbol(t3, Decl(castingTuple.ts, 29, 3))
 >numStrTuple : Symbol(numStrTuple, Decl(castingTuple.ts, 10, 3))
 
 var t9 = <[A, I]>classCDTuple;
->t9 : Symbol(t9, Decl(castingTuple.ts, 28, 3))
+>t9 : Symbol(t9, Decl(castingTuple.ts, 30, 3))
 >A : Symbol(A, Decl(castingTuple.ts, 0, 15))
 >I : Symbol(I, Decl(castingTuple.ts, 0, 0))
->classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 13, 3))
+>classCDTuple : Symbol(classCDTuple, Decl(castingTuple.ts, 15, 3))
 
 var array1 = <number[]>numStrTuple;
->array1 : Symbol(array1, Decl(castingTuple.ts, 20, 3), Decl(castingTuple.ts, 29, 3))
+>array1 : Symbol(array1, Decl(castingTuple.ts, 22, 3), Decl(castingTuple.ts, 31, 3))
 >numStrTuple : Symbol(numStrTuple, Decl(castingTuple.ts, 10, 3))
 
 t4[2] = 10;
diff --git a/tests/baselines/reference/castingTuple.types b/tests/baselines/reference/castingTuple.types
index 23d2e51a576..0b9aa0a1487 100644
--- a/tests/baselines/reference/castingTuple.types
+++ b/tests/baselines/reference/castingTuple.types
@@ -52,6 +52,16 @@ var numStrBoolTuple = <[number, string, boolean]>numStrTuple;
 ><[number, string, boolean]>numStrTuple : [number, string, boolean]
 >numStrTuple : [number, string]
 
+var shorter = numStrBoolTuple as [number, string]
+>shorter : [number, string]
+>numStrBoolTuple as [number, string] : [number, string]
+>numStrBoolTuple : [number, string, boolean]
+
+var longer = numStrTuple as [number, string, boolean]
+>longer : [number, string, boolean]
+>numStrTuple as [number, string, boolean] : [number, string, boolean]
+>numStrTuple : [number, string]
+
 var classCDTuple: [C, D] = [new C(), new D()];
 >classCDTuple : [C, D]
 >C : C
diff --git a/tests/baselines/reference/checkJsxChildrenProperty14.errors.txt b/tests/baselines/reference/checkJsxChildrenProperty14.errors.txt
new file mode 100644
index 00000000000..ecae349e19e
--- /dev/null
+++ b/tests/baselines/reference/checkJsxChildrenProperty14.errors.txt
@@ -0,0 +1,56 @@
+tests/cases/conformance/jsx/file.tsx(42,27): error TS2322: Type '{ a: 10; b: "hi"; children: Element[]; }' is not assignable to type 'IntrinsicAttributes & SingleChildProp'.
+  Type '{ a: 10; b: "hi"; children: Element[]; }' is not assignable to type 'SingleChildProp'.
+    Types of property 'children' are incompatible.
+      Type 'Element[]' is not assignable to type 'Element'.
+        Property 'type' is missing in type 'Element[]'.
+
+
+==== tests/cases/conformance/jsx/file.tsx (1 errors) ====
+    import React = require('react');
+    
+    interface Prop {
+        a: number,
+        b: string,
+        children: JSX.Element | JSX.Element[];
+    }
+    
+    class Button extends React.Component<any, any> {
+        render() {
+            return (<div>My Button</div>)
+        }
+    }
+    
+    function AnotherButton(p: any) {
+        return <h1>Just Another Button</h1>;
+    }
+    
+    function Comp(p: Prop) {
+        return <div>{p.b}</div>;
+    }
+    
+    // OK
+    let k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+    let k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+    let k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+    
+    interface SingleChildProp {
+        a: number,
+        b: string,
+        children: JSX.Element;
+    }
+    
+    function SingleChildComp(p: SingleChildProp) {
+        return <div>{p.b}</div>;
+    }
+    
+    // OK
+    let k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+    
+    // Error
+    let k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
+                              ~~~~~~~~~~~~~
+!!! error TS2322: Type '{ a: 10; b: "hi"; children: Element[]; }' is not assignable to type 'IntrinsicAttributes & SingleChildProp'.
+!!! error TS2322:   Type '{ a: 10; b: "hi"; children: Element[]; }' is not assignable to type 'SingleChildProp'.
+!!! error TS2322:     Types of property 'children' are incompatible.
+!!! error TS2322:       Type 'Element[]' is not assignable to type 'Element'.
+!!! error TS2322:         Property 'type' is missing in type 'Element[]'.
\ No newline at end of file
diff --git a/tests/baselines/reference/checkJsxChildrenProperty14.js b/tests/baselines/reference/checkJsxChildrenProperty14.js
new file mode 100644
index 00000000000..182b0f0a879
--- /dev/null
+++ b/tests/baselines/reference/checkJsxChildrenProperty14.js
@@ -0,0 +1,85 @@
+//// [file.tsx]
+import React = require('react');
+
+interface Prop {
+    a: number,
+    b: string,
+    children: JSX.Element | JSX.Element[];
+}
+
+class Button extends React.Component<any, any> {
+    render() {
+        return (<div>My Button</div>)
+    }
+}
+
+function AnotherButton(p: any) {
+    return <h1>Just Another Button</h1>;
+}
+
+function Comp(p: Prop) {
+    return <div>{p.b}</div>;
+}
+
+// OK
+let k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+let k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+let k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+
+interface SingleChildProp {
+    a: number,
+    b: string,
+    children: JSX.Element;
+}
+
+function SingleChildComp(p: SingleChildProp) {
+    return <div>{p.b}</div>;
+}
+
+// OK
+let k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+
+// Error
+let k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
+
+//// [file.jsx]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+var React = require("react");
+var Button = /** @class */ (function (_super) {
+    __extends(Button, _super);
+    function Button() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    Button.prototype.render = function () {
+        return (<div>My Button</div>);
+    };
+    return Button;
+}(React.Component));
+function AnotherButton(p) {
+    return <h1>Just Another Button</h1>;
+}
+function Comp(p) {
+    return <div>{p.b}</div>;
+}
+// OK
+var k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+var k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+var k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+function SingleChildComp(p) {
+    return <div>{p.b}</div>;
+}
+// OK
+var k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+// Error
+var k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
diff --git a/tests/baselines/reference/checkJsxChildrenProperty14.symbols b/tests/baselines/reference/checkJsxChildrenProperty14.symbols
new file mode 100644
index 00000000000..c8b5ef0e969
--- /dev/null
+++ b/tests/baselines/reference/checkJsxChildrenProperty14.symbols
@@ -0,0 +1,134 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+import React = require('react');
+>React : Symbol(React, Decl(file.tsx, 0, 0))
+
+interface Prop {
+>Prop : Symbol(Prop, Decl(file.tsx, 0, 32))
+
+    a: number,
+>a : Symbol(Prop.a, Decl(file.tsx, 2, 16))
+
+    b: string,
+>b : Symbol(Prop.b, Decl(file.tsx, 3, 14))
+
+    children: JSX.Element | JSX.Element[];
+>children : Symbol(Prop.children, Decl(file.tsx, 4, 14))
+>JSX : Symbol(JSX, Decl(react.d.ts, 2353, 1))
+>Element : Symbol(JSX.Element, Decl(react.d.ts, 2356, 27))
+>JSX : Symbol(JSX, Decl(react.d.ts, 2353, 1))
+>Element : Symbol(JSX.Element, Decl(react.d.ts, 2356, 27))
+}
+
+class Button extends React.Component<any, any> {
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>React.Component : Symbol(React.Component, Decl(react.d.ts, 158, 55), Decl(react.d.ts, 161, 66))
+>React : Symbol(React, Decl(file.tsx, 0, 0))
+>Component : Symbol(React.Component, Decl(react.d.ts, 158, 55), Decl(react.d.ts, 161, 66))
+
+    render() {
+>render : Symbol(Button.render, Decl(file.tsx, 8, 48))
+
+        return (<div>My Button</div>)
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+    }
+}
+
+function AnotherButton(p: any) {
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>p : Symbol(p, Decl(file.tsx, 14, 23))
+
+    return <h1>Just Another Button</h1>;
+>h1 : Symbol(JSX.IntrinsicElements.h1, Decl(react.d.ts, 2410, 47))
+>h1 : Symbol(JSX.IntrinsicElements.h1, Decl(react.d.ts, 2410, 47))
+}
+
+function Comp(p: Prop) {
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+>p : Symbol(p, Decl(file.tsx, 18, 14))
+>Prop : Symbol(Prop, Decl(file.tsx, 0, 32))
+
+    return <div>{p.b}</div>;
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+>p.b : Symbol(Prop.b, Decl(file.tsx, 3, 14))
+>p : Symbol(p, Decl(file.tsx, 18, 14))
+>b : Symbol(Prop.b, Decl(file.tsx, 3, 14))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+}
+
+// OK
+let k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+>k1 : Symbol(k1, Decl(file.tsx, 23, 3))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+>a : Symbol(a, Decl(file.tsx, 23, 14))
+>b : Symbol(b, Decl(file.tsx, 23, 21))
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+
+let k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+>k2 : Symbol(k2, Decl(file.tsx, 24, 3))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+>a : Symbol(a, Decl(file.tsx, 24, 14))
+>b : Symbol(b, Decl(file.tsx, 24, 21))
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+
+let k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+>k3 : Symbol(k3, Decl(file.tsx, 25, 3))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+>a : Symbol(a, Decl(file.tsx, 25, 14))
+>b : Symbol(b, Decl(file.tsx, 25, 21))
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>Comp : Symbol(Comp, Decl(file.tsx, 16, 1))
+
+interface SingleChildProp {
+>SingleChildProp : Symbol(SingleChildProp, Decl(file.tsx, 25, 69))
+
+    a: number,
+>a : Symbol(SingleChildProp.a, Decl(file.tsx, 27, 27))
+
+    b: string,
+>b : Symbol(SingleChildProp.b, Decl(file.tsx, 28, 14))
+
+    children: JSX.Element;
+>children : Symbol(SingleChildProp.children, Decl(file.tsx, 29, 14))
+>JSX : Symbol(JSX, Decl(react.d.ts, 2353, 1))
+>Element : Symbol(JSX.Element, Decl(react.d.ts, 2356, 27))
+}
+
+function SingleChildComp(p: SingleChildProp) {
+>SingleChildComp : Symbol(SingleChildComp, Decl(file.tsx, 31, 1))
+>p : Symbol(p, Decl(file.tsx, 33, 25))
+>SingleChildProp : Symbol(SingleChildProp, Decl(file.tsx, 25, 69))
+
+    return <div>{p.b}</div>;
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+>p.b : Symbol(SingleChildProp.b, Decl(file.tsx, 28, 14))
+>p : Symbol(p, Decl(file.tsx, 33, 25))
+>b : Symbol(SingleChildProp.b, Decl(file.tsx, 28, 14))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+}
+
+// OK
+let k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+>k4 : Symbol(k4, Decl(file.tsx, 38, 3))
+>SingleChildComp : Symbol(SingleChildComp, Decl(file.tsx, 31, 1))
+>a : Symbol(a, Decl(file.tsx, 38, 25))
+>b : Symbol(b, Decl(file.tsx, 38, 32))
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>SingleChildComp : Symbol(SingleChildComp, Decl(file.tsx, 31, 1))
+
+// Error
+let k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
+>k5 : Symbol(k5, Decl(file.tsx, 41, 3))
+>SingleChildComp : Symbol(SingleChildComp, Decl(file.tsx, 31, 1))
+>a : Symbol(a, Decl(file.tsx, 41, 25))
+>b : Symbol(b, Decl(file.tsx, 41, 32))
+>Button : Symbol(Button, Decl(file.tsx, 6, 1))
+>AnotherButton : Symbol(AnotherButton, Decl(file.tsx, 12, 1))
+>SingleChildComp : Symbol(SingleChildComp, Decl(file.tsx, 31, 1))
+
diff --git a/tests/baselines/reference/checkJsxChildrenProperty14.types b/tests/baselines/reference/checkJsxChildrenProperty14.types
new file mode 100644
index 00000000000..a0d9797934c
--- /dev/null
+++ b/tests/baselines/reference/checkJsxChildrenProperty14.types
@@ -0,0 +1,164 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+import React = require('react');
+>React : typeof React
+
+interface Prop {
+>Prop : Prop
+
+    a: number,
+>a : number
+
+    b: string,
+>b : string
+
+    children: JSX.Element | JSX.Element[];
+>children : JSX.Element | JSX.Element[]
+>JSX : any
+>Element : JSX.Element
+>JSX : any
+>Element : JSX.Element
+}
+
+class Button extends React.Component<any, any> {
+>Button : Button
+>React.Component : React.Component<any, any>
+>React : typeof React
+>Component : typeof React.Component
+
+    render() {
+>render : () => JSX.Element
+
+        return (<div>My Button</div>)
+>(<div>My Button</div>) : JSX.Element
+><div>My Button</div> : JSX.Element
+>div : any
+>div : any
+    }
+}
+
+function AnotherButton(p: any) {
+>AnotherButton : (p: any) => JSX.Element
+>p : any
+
+    return <h1>Just Another Button</h1>;
+><h1>Just Another Button</h1> : JSX.Element
+>h1 : any
+>h1 : any
+}
+
+function Comp(p: Prop) {
+>Comp : (p: Prop) => JSX.Element
+>p : Prop
+>Prop : Prop
+
+    return <div>{p.b}</div>;
+><div>{p.b}</div> : JSX.Element
+>div : any
+>p.b : string
+>p : Prop
+>b : string
+>div : any
+}
+
+// OK
+let k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+>k1 : JSX.Element
+><Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp> : JSX.Element
+>Comp : (p: Prop) => JSX.Element
+>a : number
+>10 : 10
+>b : string
+><></> : JSX.Element
+><Button /> : JSX.Element
+>Button : typeof Button
+><AnotherButton /> : JSX.Element
+>AnotherButton : (p: any) => JSX.Element
+>Comp : (p: Prop) => JSX.Element
+
+let k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+>k2 : JSX.Element
+><Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp> : JSX.Element
+>Comp : (p: Prop) => JSX.Element
+>a : number
+>10 : 10
+>b : string
+><><Button /></> : JSX.Element
+><Button /> : JSX.Element
+>Button : typeof Button
+><AnotherButton /> : JSX.Element
+>AnotherButton : (p: any) => JSX.Element
+>Comp : (p: Prop) => JSX.Element
+
+let k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+>k3 : JSX.Element
+><Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp> : JSX.Element
+>Comp : (p: Prop) => JSX.Element
+>a : number
+>10 : 10
+>b : string
+><><Button /><AnotherButton /></> : JSX.Element
+><Button /> : JSX.Element
+>Button : typeof Button
+><AnotherButton /> : JSX.Element
+>AnotherButton : (p: any) => JSX.Element
+>Comp : (p: Prop) => JSX.Element
+
+interface SingleChildProp {
+>SingleChildProp : SingleChildProp
+
+    a: number,
+>a : number
+
+    b: string,
+>b : string
+
+    children: JSX.Element;
+>children : JSX.Element
+>JSX : any
+>Element : JSX.Element
+}
+
+function SingleChildComp(p: SingleChildProp) {
+>SingleChildComp : (p: SingleChildProp) => JSX.Element
+>p : SingleChildProp
+>SingleChildProp : SingleChildProp
+
+    return <div>{p.b}</div>;
+><div>{p.b}</div> : JSX.Element
+>div : any
+>p.b : string
+>p : SingleChildProp
+>b : string
+>div : any
+}
+
+// OK
+let k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+>k4 : JSX.Element
+><SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp> : JSX.Element
+>SingleChildComp : (p: SingleChildProp) => JSX.Element
+>a : number
+>10 : 10
+>b : string
+><><Button /><AnotherButton /></> : JSX.Element
+><Button /> : JSX.Element
+>Button : typeof Button
+><AnotherButton /> : JSX.Element
+>AnotherButton : (p: any) => JSX.Element
+>SingleChildComp : (p: SingleChildProp) => JSX.Element
+
+// Error
+let k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
+>k5 : JSX.Element
+><SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp> : JSX.Element
+>SingleChildComp : (p: SingleChildProp) => JSX.Element
+>a : number
+>10 : 10
+>b : string
+><></> : JSX.Element
+><Button /> : JSX.Element
+>Button : typeof Button
+><AnotherButton /> : JSX.Element
+>AnotherButton : (p: any) => JSX.Element
+>SingleChildComp : (p: SingleChildProp) => JSX.Element
+
diff --git a/tests/baselines/reference/classAbstractConstructorAssignability.errors.txt b/tests/baselines/reference/classAbstractConstructorAssignability.errors.txt
index 0f834665346..3ad45cc2b04 100644
--- a/tests/baselines/reference/classAbstractConstructorAssignability.errors.txt
+++ b/tests/baselines/reference/classAbstractConstructorAssignability.errors.txt
@@ -2,7 +2,7 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
   Cannot assign an abstract constructor type to a non-abstract constructor type.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractConstructorAssignability.ts(9,5): error TS2322: Type 'typeof B' is not assignable to type 'typeof C'.
   Cannot assign an abstract constructor type to a non-abstract constructor type.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractConstructorAssignability.ts(12,1): error TS2511: Cannot create an instance of the abstract class 'B'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractConstructorAssignability.ts(12,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractConstructorAssignability.ts (3 errors) ====
@@ -25,5 +25,5 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     new AA;
     new BB;
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'B'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new CC;
\ No newline at end of file
diff --git a/tests/baselines/reference/classAbstractFactoryFunction.errors.txt b/tests/baselines/reference/classAbstractFactoryFunction.errors.txt
index 1b281f35260..2e7b3ad8f46 100644
--- a/tests/baselines/reference/classAbstractFactoryFunction.errors.txt
+++ b/tests/baselines/reference/classAbstractFactoryFunction.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractFactoryFunction.ts(9,12): error TS2511: Cannot create an instance of the abstract class 'B'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractFactoryFunction.ts(9,12): error TS2511: Cannot create an instance of an abstract class.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractFactoryFunction.ts(13,6): error TS2345: Argument of type 'typeof B' is not assignable to parameter of type 'typeof A'.
   Cannot assign an abstract constructor type to a non-abstract constructor type.
 
@@ -14,7 +14,7 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     function NewB(Factory: typeof B) {
         return new B;
                ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'B'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     }
     
     NewA(A);
diff --git a/tests/baselines/reference/classAbstractImportInstantiation.errors.txt b/tests/baselines/reference/classAbstractImportInstantiation.errors.txt
index 76110afa4ff..a01c75b6dae 100644
--- a/tests/baselines/reference/classAbstractImportInstantiation.errors.txt
+++ b/tests/baselines/reference/classAbstractImportInstantiation.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractImportInstantiation.ts(4,5): error TS2511: Cannot create an instance of the abstract class 'A'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractImportInstantiation.ts(9,1): error TS2511: Cannot create an instance of the abstract class 'A'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractImportInstantiation.ts(4,5): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractImportInstantiation.ts(9,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractImportInstantiation.ts (2 errors) ====
@@ -8,12 +8,12 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
         
         new A;
         ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     }
     
     import myA = M.A;
     
     new myA;
     ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/classAbstractInAModule.errors.txt b/tests/baselines/reference/classAbstractInAModule.errors.txt
index 426da866087..18bb6d4391e 100644
--- a/tests/baselines/reference/classAbstractInAModule.errors.txt
+++ b/tests/baselines/reference/classAbstractInAModule.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInAModule.ts(6,1): error TS2511: Cannot create an instance of the abstract class 'A'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInAModule.ts(6,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInAModule.ts (1 errors) ====
@@ -9,5 +9,5 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     new M.A;
     ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new M.B;
\ No newline at end of file
diff --git a/tests/baselines/reference/classAbstractInstantiations1.errors.txt b/tests/baselines/reference/classAbstractInstantiations1.errors.txt
index d1c159858a4..bc696ce19db 100644
--- a/tests/baselines/reference/classAbstractInstantiations1.errors.txt
+++ b/tests/baselines/reference/classAbstractInstantiations1.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(11,1): error TS2511: Cannot create an instance of the abstract class 'A'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(12,1): error TS2511: Cannot create an instance of the abstract class 'A'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(14,1): error TS2511: Cannot create an instance of the abstract class 'C'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(11,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(12,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts(14,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations1.ts (3 errors) ====
@@ -16,14 +16,14 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     new A;
     ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new A(1); // should report 1 error
     ~~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new B;
     new C;
     ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'C'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     
     var a : A;
     var b : B;
diff --git a/tests/baselines/reference/classAbstractInstantiations2.errors.txt b/tests/baselines/reference/classAbstractInstantiations2.errors.txt
index 15b63a6d3e8..d05e05517b2 100644
--- a/tests/baselines/reference/classAbstractInstantiations2.errors.txt
+++ b/tests/baselines/reference/classAbstractInstantiations2.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(10,1): error TS2511: Cannot create an instance of the abstract class 'B'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(10,1): error TS2511: Cannot create an instance of an abstract class.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(13,5): error TS2322: Type 'typeof B' is not assignable to type 'typeof A'.
   Cannot assign an abstract constructor type to a non-abstract constructor type.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(17,5): error TS2511: Cannot create an instance of the abstract class 'B'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(21,1): error TS2511: Cannot create an instance of the abstract class 'B'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(17,5): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(21,1): error TS2511: Cannot create an instance of an abstract class.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(23,15): error TS2449: Class 'C' used before its declaration.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(26,7): error TS2515: Non-abstract class 'C' does not implement inherited abstract member 'bar' from class 'B'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts(46,5): error TS2391: Function implementation is missing or not immediately following the declaration.
@@ -22,7 +22,7 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     new B; // error
     ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'B'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     
     var BB: typeof B = B;
     var AA: typeof A = BB; // error, AA is not of abstract type.
@@ -34,13 +34,13 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     function constructB(Factory : typeof B) {
         new Factory; // error -- Factory is of type typeof B.
         ~~~~~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'B'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     }
     
     var BB = B;
     new BB; // error -- BB is of type typeof B.
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'B'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     
     var x : any = C;
                   ~
diff --git a/tests/baselines/reference/classAbstractMergedDeclaration.errors.txt b/tests/baselines/reference/classAbstractMergedDeclaration.errors.txt
index 3e18d8796fb..fc15ca410e8 100644
--- a/tests/baselines/reference/classAbstractMergedDeclaration.errors.txt
+++ b/tests/baselines/reference/classAbstractMergedDeclaration.errors.txt
@@ -6,14 +6,14 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(26,15): error TS2300: Duplicate identifier 'DCC1'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(28,15): error TS2300: Duplicate identifier 'DCC2'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(29,24): error TS2300: Duplicate identifier 'DCC2'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(31,1): error TS2511: Cannot create an instance of the abstract class 'CM'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(32,1): error TS2511: Cannot create an instance of the abstract class 'MC'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(33,1): error TS2511: Cannot create an instance of the abstract class 'CI'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(34,1): error TS2511: Cannot create an instance of the abstract class 'IC'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(35,1): error TS2511: Cannot create an instance of the abstract class 'CC1'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(37,1): error TS2511: Cannot create an instance of the abstract class 'DCI'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(38,1): error TS2511: Cannot create an instance of the abstract class 'DIC'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(39,1): error TS2511: Cannot create an instance of the abstract class 'DCC1'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(31,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(32,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(33,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(34,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(35,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(37,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(38,1): error TS2511: Cannot create an instance of an abstract class.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(39,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts (16 errors) ====
@@ -65,27 +65,27 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     new CM;
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'CM'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new MC;
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'MC'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new CI;
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'CI'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new IC;
     ~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'IC'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new CC1;
     ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'CC1'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new CC2;
     new DCI;
     ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'DCI'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new DIC;
     ~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'DIC'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new DCC1;
     ~~~~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'DCC1'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new DCC2;
\ No newline at end of file
diff --git a/tests/baselines/reference/classAbstractSingleLineDecl.errors.txt b/tests/baselines/reference/classAbstractSingleLineDecl.errors.txt
index 0670ea108ea..1bdabfefe6d 100644
--- a/tests/baselines/reference/classAbstractSingleLineDecl.errors.txt
+++ b/tests/baselines/reference/classAbstractSingleLineDecl.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractSingleLineDecl.ts(3,1): error TS2304: Cannot find name 'abstract'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractSingleLineDecl.ts(6,1): error TS2304: Cannot find name 'abstract'.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractSingleLineDecl.ts(10,1): error TS2511: Cannot create an instance of the abstract class 'A'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractSingleLineDecl.ts(10,1): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractSingleLineDecl.ts (3 errors) ====
@@ -19,6 +19,6 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     new A;
     ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'A'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     new B;
     new C;
\ No newline at end of file
diff --git a/tests/baselines/reference/classAbstractUsingAbstractMethod1.errors.txt b/tests/baselines/reference/classAbstractUsingAbstractMethod1.errors.txt
index df3682a36af..282fa3a53aa 100644
--- a/tests/baselines/reference/classAbstractUsingAbstractMethod1.errors.txt
+++ b/tests/baselines/reference/classAbstractUsingAbstractMethod1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractUsingAbstractMethod1.ts(16,5): error TS2511: Cannot create an instance of the abstract class 'C'.
+tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractUsingAbstractMethod1.ts(16,5): error TS2511: Cannot create an instance of an abstract class.
 
 
 ==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractUsingAbstractMethod1.ts (1 errors) ====
@@ -19,5 +19,5 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     
     a = new C; // error, cannot instantiate abstract class.
         ~~~~~
-!!! error TS2511: Cannot create an instance of the abstract class 'C'.
+!!! error TS2511: Cannot create an instance of an abstract class.
     a.foo();
\ No newline at end of file
diff --git a/tests/baselines/reference/commentEmitAtEndOfFile1.js b/tests/baselines/reference/commentEmitAtEndOfFile1.js
index 1be031fa84a..d6ba7b158d6 100644
--- a/tests/baselines/reference/commentEmitAtEndOfFile1.js
+++ b/tests/baselines/reference/commentEmitAtEndOfFile1.js
@@ -18,4 +18,4 @@ var foo;
 (function (foo) {
     function bar() { }
 })(foo || (foo = {}));
-// test #4 
+// test #4
diff --git a/tests/baselines/reference/commonJsUnusedLocals.errors.txt b/tests/baselines/reference/commonJsUnusedLocals.errors.txt
new file mode 100644
index 00000000000..b8e2159d432
--- /dev/null
+++ b/tests/baselines/reference/commonJsUnusedLocals.errors.txt
@@ -0,0 +1,9 @@
+/a.js(1,7): error TS6133: 'x' is declared but its value is never read.
+
+
+==== /a.js (1 errors) ====
+    const x = 0;
+          ~
+!!! error TS6133: 'x' is declared but its value is never read.
+    exports.y = 1;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/commonJsUnusedLocals.symbols b/tests/baselines/reference/commonJsUnusedLocals.symbols
new file mode 100644
index 00000000000..08155bc4d26
--- /dev/null
+++ b/tests/baselines/reference/commonJsUnusedLocals.symbols
@@ -0,0 +1,9 @@
+=== /a.js ===
+const x = 0;
+>x : Symbol(x, Decl(a.js, 0, 5))
+
+exports.y = 1;
+>exports.y : Symbol(y, Decl(a.js, 0, 12))
+>exports : Symbol(y, Decl(a.js, 0, 12))
+>y : Symbol(y, Decl(a.js, 0, 12))
+
diff --git a/tests/baselines/reference/commonJsUnusedLocals.types b/tests/baselines/reference/commonJsUnusedLocals.types
new file mode 100644
index 00000000000..e792ad8e782
--- /dev/null
+++ b/tests/baselines/reference/commonJsUnusedLocals.types
@@ -0,0 +1,12 @@
+=== /a.js ===
+const x = 0;
+>x : 0
+>0 : 0
+
+exports.y = 1;
+>exports.y = 1 : 1
+>exports.y : number
+>exports : typeof "/a"
+>y : number
+>1 : 1
+
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
index 079a1e276fb..bcd87998f83 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnCallSignature.js
@@ -505,4 +505,4 @@ var r8b8 = b8 !== a8;
 var r8b9 = b9 !== a9;
 var r8b10 = b10 !== a10;
 var r8b11 = b11 !== a11;
-//var r8b12 = b12 !== a12; 
+//var r8b12 = b12 !== a12;
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
index 38097a936e3..1721f564865 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnConstructorSignature.js
@@ -431,4 +431,4 @@ var r8b6 = b6 !== a6;
 var r8b7 = b7 !== a7;
 var r8b8 = b8 !== a8;
 var r8b9 = b9 !== a9;
-//var r8b10 = b10 !== a10; 
+//var r8b10 = b10 !== a10;
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
index 87359ea0074..72dd4be0afc 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedCallSignature.js
@@ -320,4 +320,4 @@ var r8b3 = b3 !== a3;
 var r8b4 = b4 !== a4;
 var r8b5 = b5 !== a5;
 var r8b6 = b6 !== a6;
-//var r8b7 = b7 !== a7; 
+//var r8b7 = b7 !== a7;
diff --git a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
index fcfbfa4bfbc..19183773406 100644
--- a/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
+++ b/tests/baselines/reference/comparisonOperatorWithSubtypeObjectOnInstantiatedConstructorSignature.js
@@ -320,4 +320,4 @@ var r8b3 = b3 !== a3;
 var r8b4 = b4 !== a4;
 var r8b5 = b5 !== a5;
 var r8b6 = b6 !== a6;
-//var r8b7 = b7 !== a7; 
+//var r8b7 = b7 !== a7;
diff --git a/tests/baselines/reference/computedPropertyNames12_ES5.js b/tests/baselines/reference/computedPropertyNames12_ES5.js
index b3743a36b2b..e8bcf325c34 100644
--- a/tests/baselines/reference/computedPropertyNames12_ES5.js
+++ b/tests/baselines/reference/computedPropertyNames12_ES5.js
@@ -22,10 +22,12 @@ var n;
 var a;
 var C = /** @class */ (function () {
     function C() {
-        this[n] = n;
-        this[s + n] = 2;
+        this[_a] = n;
+        this[_b] = 2;
         this["hello bye"] = 0;
     }
-    C["hello " + a + " bye"] = 0;
+    _a = n, s + s, _b = s + n, +s, _c = "hello " + a + " bye";
+    C[_c] = 0;
     return C;
+    var _a, _b, _c;
 }());
diff --git a/tests/baselines/reference/computedPropertyNames12_ES6.js b/tests/baselines/reference/computedPropertyNames12_ES6.js
index fd6ccb6e486..6f91ec92cc9 100644
--- a/tests/baselines/reference/computedPropertyNames12_ES6.js
+++ b/tests/baselines/reference/computedPropertyNames12_ES6.js
@@ -22,9 +22,11 @@ var n;
 var a;
 class C {
     constructor() {
-        this[n] = n;
-        this[s + n] = 2;
+        this[_a] = n;
+        this[_b] = 2;
         this[`hello bye`] = 0;
     }
 }
-C[`hello ${a} bye`] = 0;
+_a = n, s + s, _b = s + n, +s, _c = `hello ${a} bye`;
+C[_c] = 0;
+var _a, _b, _c;
diff --git a/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.types b/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.types
index 3a655853163..a9767c72fc7 100644
--- a/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.types
+++ b/tests/baselines/reference/conditionalOperatorWithIdenticalBCT.types
@@ -45,7 +45,7 @@ var result1 = true ? x : a;
 
 //Expr1 and Expr2 are literals
 true ? {} : 1;
->true ? {} : 1 : {}
+>true ? {} : 1 : 1 | {}
 >true : true
 >{} : {}
 >1 : 1
@@ -64,13 +64,13 @@ true ? { a: 1 } : { a: 2, b: 'string' };
 
 var result2 = true ? {} : 1;
 >result2 : {}
->true ? {} : 1 : {}
+>true ? {} : 1 : 1 | {}
 >true : true
 >{} : {}
 >1 : 1
 
 var result3 = true ? { a: 1 } : { a: 2, b: 'string' };
->result3 : { a: number; } | { a: number; b: string; }
+>result3 : { a: number; b?: undefined; } | { a: number; b: string; }
 >true ? { a: 1 } : { a: 2, b: 'string' } : { a: number; } | { a: number; b: string; }
 >true : true
 >{ a: 1 } : { a: number; }
@@ -125,7 +125,7 @@ var result5 = true ? a : x;
 
 //Expr1 and Expr2 are literals
 true ? 1 : {};
->true ? 1 : {} : {}
+>true ? 1 : {} : 1 | {}
 >true : true
 >1 : 1
 >{} : {}
@@ -144,13 +144,13 @@ true ? { a: 2, b: 'string' } : { a: 1 };
 
 var result6 = true ? 1 : {};
 >result6 : {}
->true ? 1 : {} : {}
+>true ? 1 : {} : 1 | {}
 >true : true
 >1 : 1
 >{} : {}
 
 var result7 = true ? { a: 2, b: 'string' } : { a: 1 };
->result7 : { a: number; b: string; } | { a: number; }
+>result7 : { a: number; b: string; } | { a: number; b?: undefined; }
 >true ? { a: 2, b: 'string' } : { a: 1 } : { a: number; b: string; } | { a: number; }
 >true : true
 >{ a: 2, b: 'string' } : { a: number; b: string; }
diff --git a/tests/baselines/reference/contextualTypeWithTuple.errors.txt b/tests/baselines/reference/contextualTypeWithTuple.errors.txt
index a488d8c7648..58a90919c5b 100644
--- a/tests/baselines/reference/contextualTypeWithTuple.errors.txt
+++ b/tests/baselines/reference/contextualTypeWithTuple.errors.txt
@@ -1,8 +1,6 @@
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(3,5): error TS2322: Type '[number, string, boolean]' is not assignable to type '[number, string]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number | boolean' is not assignable to type '() => string | number'.
-      Type 'string | number | boolean' is not assignable to type 'string | number'.
-        Type 'true' is not assignable to type 'string | number'.
+  Types of property 'length' are incompatible.
+    Type '3' is not assignable to type '2'.
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(15,1): error TS2322: Type '[number, string, boolean]' is not assignable to type '[number, string]'.
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(18,1): error TS2322: Type '[{}, number]' is not assignable to type '[{ a: string; }, number]'.
   Type '{}' is not assignable to type '{ a: string; }'.
@@ -10,10 +8,11 @@ tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(18,1): error TS23
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(19,1): error TS2322: Type '[number, string]' is not assignable to type '[number, string, boolean]'.
   Property '2' is missing in type '[number, string]'.
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(20,5): error TS2322: Type '[string, string, number]' is not assignable to type '[string, string]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number' is not assignable to type '() => string'.
-      Type 'string | number' is not assignable to type 'string'.
-        Type 'number' is not assignable to type 'string'.
+  Types of property 'length' are incompatible.
+    Type '3' is not assignable to type '2'.
+tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(23,1): error TS2322: Type '[C, string | number, D]' is not assignable to type '[C, string | number]'.
+  Types of property 'length' are incompatible.
+    Type '3' is not assignable to type '2'.
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(24,1): error TS2322: Type '[C, string | number]' is not assignable to type '[C, string | number, D]'.
   Property '2' is missing in type '[C, string | number]'.
 tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(25,1): error TS2322: Type '[number, string | number]' is not assignable to type '[number, string]'.
@@ -21,16 +20,14 @@ tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(25,1): error TS23
     Type 'number' is not assignable to type 'string'.
 
 
-==== tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts (7 errors) ====
+==== tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts (8 errors) ====
     // no error
     var numStrTuple: [number, string] = [5, "hello"];
     var numStrTuple2: [number, string] = [5, "foo", true];
         ~~~~~~~~~~~~
 !!! error TS2322: Type '[number, string, boolean]' is not assignable to type '[number, string]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number | boolean' is not assignable to type '() => string | number'.
-!!! error TS2322:       Type 'string | number | boolean' is not assignable to type 'string | number'.
-!!! error TS2322:         Type 'true' is not assignable to type 'string | number'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '3' is not assignable to type '2'.
     var numStrBoolTuple: [number, string, boolean] = [5, "foo", true];
     var objNumTuple: [{ a: string }, number] = [{ a: "world" }, 5];
     var strTupleTuple: [string, [number, {}]] = ["bar", [5, { x: 1, y: 1 }]];
@@ -59,13 +56,15 @@ tests/cases/conformance/types/tuple/contextualTypeWithTuple.ts(25,1): error TS23
     var strStrTuple: [string, string] = ["foo", "bar", 5];
         ~~~~~~~~~~~
 !!! error TS2322: Type '[string, string, number]' is not assignable to type '[string, string]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number' is not assignable to type '() => string'.
-!!! error TS2322:       Type 'string | number' is not assignable to type 'string'.
-!!! error TS2322:         Type 'number' is not assignable to type 'string'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '3' is not assignable to type '2'.
     
     unionTuple = unionTuple1;
     unionTuple = unionTuple2;
+    ~~~~~~~~~~
+!!! error TS2322: Type '[C, string | number, D]' is not assignable to type '[C, string | number]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '3' is not assignable to type '2'.
     unionTuple2 = unionTuple;
     ~~~~~~~~~~~
 !!! error TS2322: Type '[C, string | number]' is not assignable to type '[C, string | number, D]'.
diff --git a/tests/baselines/reference/contextualTypingOfOptionalMembers.errors.txt b/tests/baselines/reference/contextualTypingOfOptionalMembers.errors.txt
new file mode 100644
index 00000000000..02c94400e21
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfOptionalMembers.errors.txt
@@ -0,0 +1,80 @@
+tests/cases/compiler/index.tsx(73,34): error TS7006: Parameter 's' implicitly has an 'any' type.
+
+
+==== tests/cases/compiler/index.tsx (1 errors) ====
+    interface ActionsObject<State> {
+        [prop: string]: (state: State) => State;
+    }
+    
+    interface Options<State, Actions> {
+        state?: State;
+        view?: (state: State, actions: Actions) => any;
+        actions: string | Actions;
+    }
+    
+    declare function app<State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>): void;
+    
+    app({
+        state: 100,
+        actions: {
+            foo: s => s // Should be typed number => number
+        },
+        view: (s, a) => undefined as any,
+    });
+    
+    
+    interface Bar {
+        bar: (a: number) => void;
+    }
+    
+    declare function foo<T extends Bar>(x: string | T): T;
+    
+    const y = foo({
+        bar(x) { // Should be typed number => void
+        }
+    });
+    
+    interface Options2<State, Actions> {
+        state?: State;
+        view?: (state: State, actions: Actions) => any;
+        actions?: Actions;
+    }
+    
+    declare function app2<State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>): void;
+    
+    app2({
+        state: 100,
+        actions: {
+            foo: s => s // Should be typed number => number
+        },
+        view: (s, a) => undefined as any,
+    });
+    
+    
+    type ActionsArray<State> = ((state: State) => State)[];
+    
+    declare function app3<State, Actions extends ActionsArray<State>>(obj: Options<State, Actions>): void;
+    
+    app3({
+        state: 100,
+        actions: [
+            s => s // Should be typed number => number
+        ],
+        view: (s, a) => undefined as any,
+    });
+    
+    namespace JSX {
+        export interface Element {}
+        export interface IntrinsicElements {}
+    }
+    
+    interface ActionsObjectOr<State> {
+        [prop: string]: ((state: State) => State) | State;
+    }
+    
+    declare function App4<State, Actions extends ActionsObjectOr<State>>(props: Options<State, Actions>["actions"] & { state: State }): JSX.Element;
+    
+    const a = <App4 state={100} foo={s => s} />; // TODO: should be number => number, but JSX resolution is missing an inferential pass
+                                     ~
+!!! error TS7006: Parameter 's' implicitly has an 'any' type.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/contextualTypingOfOptionalMembers.js b/tests/baselines/reference/contextualTypingOfOptionalMembers.js
new file mode 100644
index 00000000000..289d64546e8
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfOptionalMembers.js
@@ -0,0 +1,103 @@
+//// [index.tsx]
+interface ActionsObject<State> {
+    [prop: string]: (state: State) => State;
+}
+
+interface Options<State, Actions> {
+    state?: State;
+    view?: (state: State, actions: Actions) => any;
+    actions: string | Actions;
+}
+
+declare function app<State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>): void;
+
+app({
+    state: 100,
+    actions: {
+        foo: s => s // Should be typed number => number
+    },
+    view: (s, a) => undefined as any,
+});
+
+
+interface Bar {
+    bar: (a: number) => void;
+}
+
+declare function foo<T extends Bar>(x: string | T): T;
+
+const y = foo({
+    bar(x) { // Should be typed number => void
+    }
+});
+
+interface Options2<State, Actions> {
+    state?: State;
+    view?: (state: State, actions: Actions) => any;
+    actions?: Actions;
+}
+
+declare function app2<State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>): void;
+
+app2({
+    state: 100,
+    actions: {
+        foo: s => s // Should be typed number => number
+    },
+    view: (s, a) => undefined as any,
+});
+
+
+type ActionsArray<State> = ((state: State) => State)[];
+
+declare function app3<State, Actions extends ActionsArray<State>>(obj: Options<State, Actions>): void;
+
+app3({
+    state: 100,
+    actions: [
+        s => s // Should be typed number => number
+    ],
+    view: (s, a) => undefined as any,
+});
+
+namespace JSX {
+    export interface Element {}
+    export interface IntrinsicElements {}
+}
+
+interface ActionsObjectOr<State> {
+    [prop: string]: ((state: State) => State) | State;
+}
+
+declare function App4<State, Actions extends ActionsObjectOr<State>>(props: Options<State, Actions>["actions"] & { state: State }): JSX.Element;
+
+const a = <App4 state={100} foo={s => s} />; // TODO: should be number => number, but JSX resolution is missing an inferential pass
+
+
+//// [index.jsx]
+app({
+    state: 100,
+    actions: {
+        foo: function (s) { return s; } // Should be typed number => number
+    },
+    view: function (s, a) { return undefined; }
+});
+var y = foo({
+    bar: function (x) {
+    }
+});
+app2({
+    state: 100,
+    actions: {
+        foo: function (s) { return s; } // Should be typed number => number
+    },
+    view: function (s, a) { return undefined; }
+});
+app3({
+    state: 100,
+    actions: [
+        function (s) { return s; } // Should be typed number => number
+    ],
+    view: function (s, a) { return undefined; }
+});
+var a = <App4 state={100} foo={function (s) { return s; }}/>; // TODO: should be number => number, but JSX resolution is missing an inferential pass
diff --git a/tests/baselines/reference/contextualTypingOfOptionalMembers.symbols b/tests/baselines/reference/contextualTypingOfOptionalMembers.symbols
new file mode 100644
index 00000000000..14d8ef41b3a
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfOptionalMembers.symbols
@@ -0,0 +1,235 @@
+=== tests/cases/compiler/index.tsx ===
+interface ActionsObject<State> {
+>ActionsObject : Symbol(ActionsObject, Decl(index.tsx, 0, 0))
+>State : Symbol(State, Decl(index.tsx, 0, 24))
+
+    [prop: string]: (state: State) => State;
+>prop : Symbol(prop, Decl(index.tsx, 1, 5))
+>state : Symbol(state, Decl(index.tsx, 1, 21))
+>State : Symbol(State, Decl(index.tsx, 0, 24))
+>State : Symbol(State, Decl(index.tsx, 0, 24))
+}
+
+interface Options<State, Actions> {
+>Options : Symbol(Options, Decl(index.tsx, 2, 1))
+>State : Symbol(State, Decl(index.tsx, 4, 18))
+>Actions : Symbol(Actions, Decl(index.tsx, 4, 24))
+
+    state?: State;
+>state : Symbol(Options.state, Decl(index.tsx, 4, 35))
+>State : Symbol(State, Decl(index.tsx, 4, 18))
+
+    view?: (state: State, actions: Actions) => any;
+>view : Symbol(Options.view, Decl(index.tsx, 5, 18))
+>state : Symbol(state, Decl(index.tsx, 6, 12))
+>State : Symbol(State, Decl(index.tsx, 4, 18))
+>actions : Symbol(actions, Decl(index.tsx, 6, 25))
+>Actions : Symbol(Actions, Decl(index.tsx, 4, 24))
+
+    actions: string | Actions;
+>actions : Symbol(Options.actions, Decl(index.tsx, 6, 51))
+>Actions : Symbol(Actions, Decl(index.tsx, 4, 24))
+}
+
+declare function app<State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>): void;
+>app : Symbol(app, Decl(index.tsx, 8, 1))
+>State : Symbol(State, Decl(index.tsx, 10, 21))
+>Actions : Symbol(Actions, Decl(index.tsx, 10, 27))
+>ActionsObject : Symbol(ActionsObject, Decl(index.tsx, 0, 0))
+>State : Symbol(State, Decl(index.tsx, 10, 21))
+>obj : Symbol(obj, Decl(index.tsx, 10, 66))
+>Options : Symbol(Options, Decl(index.tsx, 2, 1))
+>State : Symbol(State, Decl(index.tsx, 10, 21))
+>Actions : Symbol(Actions, Decl(index.tsx, 10, 27))
+
+app({
+>app : Symbol(app, Decl(index.tsx, 8, 1))
+
+    state: 100,
+>state : Symbol(state, Decl(index.tsx, 12, 5))
+
+    actions: {
+>actions : Symbol(actions, Decl(index.tsx, 13, 15))
+
+        foo: s => s // Should be typed number => number
+>foo : Symbol(foo, Decl(index.tsx, 14, 14))
+>s : Symbol(s, Decl(index.tsx, 15, 12))
+>s : Symbol(s, Decl(index.tsx, 15, 12))
+
+    },
+    view: (s, a) => undefined as any,
+>view : Symbol(view, Decl(index.tsx, 16, 6))
+>s : Symbol(s, Decl(index.tsx, 17, 11))
+>a : Symbol(a, Decl(index.tsx, 17, 13))
+>undefined : Symbol(undefined)
+
+});
+
+
+interface Bar {
+>Bar : Symbol(Bar, Decl(index.tsx, 18, 3))
+
+    bar: (a: number) => void;
+>bar : Symbol(Bar.bar, Decl(index.tsx, 21, 15))
+>a : Symbol(a, Decl(index.tsx, 22, 10))
+}
+
+declare function foo<T extends Bar>(x: string | T): T;
+>foo : Symbol(foo, Decl(index.tsx, 23, 1))
+>T : Symbol(T, Decl(index.tsx, 25, 21))
+>Bar : Symbol(Bar, Decl(index.tsx, 18, 3))
+>x : Symbol(x, Decl(index.tsx, 25, 36))
+>T : Symbol(T, Decl(index.tsx, 25, 21))
+>T : Symbol(T, Decl(index.tsx, 25, 21))
+
+const y = foo({
+>y : Symbol(y, Decl(index.tsx, 27, 5))
+>foo : Symbol(foo, Decl(index.tsx, 23, 1))
+
+    bar(x) { // Should be typed number => void
+>bar : Symbol(bar, Decl(index.tsx, 27, 15))
+>x : Symbol(x, Decl(index.tsx, 28, 8))
+    }
+});
+
+interface Options2<State, Actions> {
+>Options2 : Symbol(Options2, Decl(index.tsx, 30, 3))
+>State : Symbol(State, Decl(index.tsx, 32, 19))
+>Actions : Symbol(Actions, Decl(index.tsx, 32, 25))
+
+    state?: State;
+>state : Symbol(Options2.state, Decl(index.tsx, 32, 36))
+>State : Symbol(State, Decl(index.tsx, 32, 19))
+
+    view?: (state: State, actions: Actions) => any;
+>view : Symbol(Options2.view, Decl(index.tsx, 33, 18))
+>state : Symbol(state, Decl(index.tsx, 34, 12))
+>State : Symbol(State, Decl(index.tsx, 32, 19))
+>actions : Symbol(actions, Decl(index.tsx, 34, 25))
+>Actions : Symbol(Actions, Decl(index.tsx, 32, 25))
+
+    actions?: Actions;
+>actions : Symbol(Options2.actions, Decl(index.tsx, 34, 51))
+>Actions : Symbol(Actions, Decl(index.tsx, 32, 25))
+}
+
+declare function app2<State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>): void;
+>app2 : Symbol(app2, Decl(index.tsx, 36, 1))
+>State : Symbol(State, Decl(index.tsx, 38, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 38, 28))
+>ActionsObject : Symbol(ActionsObject, Decl(index.tsx, 0, 0))
+>State : Symbol(State, Decl(index.tsx, 38, 22))
+>obj : Symbol(obj, Decl(index.tsx, 38, 67))
+>Options2 : Symbol(Options2, Decl(index.tsx, 30, 3))
+>State : Symbol(State, Decl(index.tsx, 38, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 38, 28))
+
+app2({
+>app2 : Symbol(app2, Decl(index.tsx, 36, 1))
+
+    state: 100,
+>state : Symbol(state, Decl(index.tsx, 40, 6))
+
+    actions: {
+>actions : Symbol(actions, Decl(index.tsx, 41, 15))
+
+        foo: s => s // Should be typed number => number
+>foo : Symbol(foo, Decl(index.tsx, 42, 14))
+>s : Symbol(s, Decl(index.tsx, 43, 12))
+>s : Symbol(s, Decl(index.tsx, 43, 12))
+
+    },
+    view: (s, a) => undefined as any,
+>view : Symbol(view, Decl(index.tsx, 44, 6))
+>s : Symbol(s, Decl(index.tsx, 45, 11))
+>a : Symbol(a, Decl(index.tsx, 45, 13))
+>undefined : Symbol(undefined)
+
+});
+
+
+type ActionsArray<State> = ((state: State) => State)[];
+>ActionsArray : Symbol(ActionsArray, Decl(index.tsx, 46, 3))
+>State : Symbol(State, Decl(index.tsx, 49, 18))
+>state : Symbol(state, Decl(index.tsx, 49, 29))
+>State : Symbol(State, Decl(index.tsx, 49, 18))
+>State : Symbol(State, Decl(index.tsx, 49, 18))
+
+declare function app3<State, Actions extends ActionsArray<State>>(obj: Options<State, Actions>): void;
+>app3 : Symbol(app3, Decl(index.tsx, 49, 55))
+>State : Symbol(State, Decl(index.tsx, 51, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 51, 28))
+>ActionsArray : Symbol(ActionsArray, Decl(index.tsx, 46, 3))
+>State : Symbol(State, Decl(index.tsx, 51, 22))
+>obj : Symbol(obj, Decl(index.tsx, 51, 66))
+>Options : Symbol(Options, Decl(index.tsx, 2, 1))
+>State : Symbol(State, Decl(index.tsx, 51, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 51, 28))
+
+app3({
+>app3 : Symbol(app3, Decl(index.tsx, 49, 55))
+
+    state: 100,
+>state : Symbol(state, Decl(index.tsx, 53, 6))
+
+    actions: [
+>actions : Symbol(actions, Decl(index.tsx, 54, 15))
+
+        s => s // Should be typed number => number
+>s : Symbol(s, Decl(index.tsx, 55, 14))
+>s : Symbol(s, Decl(index.tsx, 55, 14))
+
+    ],
+    view: (s, a) => undefined as any,
+>view : Symbol(view, Decl(index.tsx, 57, 6))
+>s : Symbol(s, Decl(index.tsx, 58, 11))
+>a : Symbol(a, Decl(index.tsx, 58, 13))
+>undefined : Symbol(undefined)
+
+});
+
+namespace JSX {
+>JSX : Symbol(JSX, Decl(index.tsx, 59, 3))
+
+    export interface Element {}
+>Element : Symbol(Element, Decl(index.tsx, 61, 15))
+
+    export interface IntrinsicElements {}
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(index.tsx, 62, 31))
+}
+
+interface ActionsObjectOr<State> {
+>ActionsObjectOr : Symbol(ActionsObjectOr, Decl(index.tsx, 64, 1))
+>State : Symbol(State, Decl(index.tsx, 66, 26))
+
+    [prop: string]: ((state: State) => State) | State;
+>prop : Symbol(prop, Decl(index.tsx, 67, 5))
+>state : Symbol(state, Decl(index.tsx, 67, 22))
+>State : Symbol(State, Decl(index.tsx, 66, 26))
+>State : Symbol(State, Decl(index.tsx, 66, 26))
+>State : Symbol(State, Decl(index.tsx, 66, 26))
+}
+
+declare function App4<State, Actions extends ActionsObjectOr<State>>(props: Options<State, Actions>["actions"] & { state: State }): JSX.Element;
+>App4 : Symbol(App4, Decl(index.tsx, 68, 1))
+>State : Symbol(State, Decl(index.tsx, 70, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 70, 28))
+>ActionsObjectOr : Symbol(ActionsObjectOr, Decl(index.tsx, 64, 1))
+>State : Symbol(State, Decl(index.tsx, 70, 22))
+>props : Symbol(props, Decl(index.tsx, 70, 69))
+>Options : Symbol(Options, Decl(index.tsx, 2, 1))
+>State : Symbol(State, Decl(index.tsx, 70, 22))
+>Actions : Symbol(Actions, Decl(index.tsx, 70, 28))
+>state : Symbol(state, Decl(index.tsx, 70, 114))
+>State : Symbol(State, Decl(index.tsx, 70, 22))
+>JSX : Symbol(JSX, Decl(index.tsx, 59, 3))
+>Element : Symbol(JSX.Element, Decl(index.tsx, 61, 15))
+
+const a = <App4 state={100} foo={s => s} />; // TODO: should be number => number, but JSX resolution is missing an inferential pass
+>a : Symbol(a, Decl(index.tsx, 72, 5))
+>App4 : Symbol(App4, Decl(index.tsx, 68, 1))
+>state : Symbol(state, Decl(index.tsx, 72, 15))
+>foo : Symbol(foo, Decl(index.tsx, 72, 27))
+>s : Symbol(s, Decl(index.tsx, 72, 33))
+>s : Symbol(s, Decl(index.tsx, 72, 33))
+
diff --git a/tests/baselines/reference/contextualTypingOfOptionalMembers.types b/tests/baselines/reference/contextualTypingOfOptionalMembers.types
new file mode 100644
index 00000000000..515685f5c53
--- /dev/null
+++ b/tests/baselines/reference/contextualTypingOfOptionalMembers.types
@@ -0,0 +1,261 @@
+=== tests/cases/compiler/index.tsx ===
+interface ActionsObject<State> {
+>ActionsObject : ActionsObject<State>
+>State : State
+
+    [prop: string]: (state: State) => State;
+>prop : string
+>state : State
+>State : State
+>State : State
+}
+
+interface Options<State, Actions> {
+>Options : Options<State, Actions>
+>State : State
+>Actions : Actions
+
+    state?: State;
+>state : State | undefined
+>State : State
+
+    view?: (state: State, actions: Actions) => any;
+>view : ((state: State, actions: Actions) => any) | undefined
+>state : State
+>State : State
+>actions : Actions
+>Actions : Actions
+
+    actions: string | Actions;
+>actions : string | Actions
+>Actions : Actions
+}
+
+declare function app<State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>): void;
+>app : <State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>) => void
+>State : State
+>Actions : Actions
+>ActionsObject : ActionsObject<State>
+>State : State
+>obj : Options<State, Actions>
+>Options : Options<State, Actions>
+>State : State
+>Actions : Actions
+
+app({
+>app({    state: 100,    actions: {        foo: s => s // Should be typed number => number    },    view: (s, a) => undefined as any,}) : void
+>app : <State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>) => void
+>{    state: 100,    actions: {        foo: s => s // Should be typed number => number    },    view: (s, a) => undefined as any,} : { state: number; actions: { foo: (s: number) => number; }; view: (s: number, a: ActionsObject<number>) => any; }
+
+    state: 100,
+>state : number
+>100 : 100
+
+    actions: {
+>actions : { foo: (s: number) => number; }
+>{        foo: s => s // Should be typed number => number    } : { foo: (s: number) => number; }
+
+        foo: s => s // Should be typed number => number
+>foo : (s: number) => number
+>s => s : (s: number) => number
+>s : number
+>s : number
+
+    },
+    view: (s, a) => undefined as any,
+>view : (s: number, a: ActionsObject<number>) => any
+>(s, a) => undefined as any : (s: number, a: ActionsObject<number>) => any
+>s : number
+>a : ActionsObject<number>
+>undefined as any : any
+>undefined : undefined
+
+});
+
+
+interface Bar {
+>Bar : Bar
+
+    bar: (a: number) => void;
+>bar : (a: number) => void
+>a : number
+}
+
+declare function foo<T extends Bar>(x: string | T): T;
+>foo : <T extends Bar>(x: string | T) => T
+>T : T
+>Bar : Bar
+>x : string | T
+>T : T
+>T : T
+
+const y = foo({
+>y : { bar(x: number): void; }
+>foo({    bar(x) { // Should be typed number => void    }}) : { bar(x: number): void; }
+>foo : <T extends Bar>(x: string | T) => T
+>{    bar(x) { // Should be typed number => void    }} : { bar(x: number): void; }
+
+    bar(x) { // Should be typed number => void
+>bar : (x: number) => void
+>x : number
+    }
+});
+
+interface Options2<State, Actions> {
+>Options2 : Options2<State, Actions>
+>State : State
+>Actions : Actions
+
+    state?: State;
+>state : State | undefined
+>State : State
+
+    view?: (state: State, actions: Actions) => any;
+>view : ((state: State, actions: Actions) => any) | undefined
+>state : State
+>State : State
+>actions : Actions
+>Actions : Actions
+
+    actions?: Actions;
+>actions : Actions | undefined
+>Actions : Actions
+}
+
+declare function app2<State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>): void;
+>app2 : <State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>) => void
+>State : State
+>Actions : Actions
+>ActionsObject : ActionsObject<State>
+>State : State
+>obj : Options2<State, Actions>
+>Options2 : Options2<State, Actions>
+>State : State
+>Actions : Actions
+
+app2({
+>app2({    state: 100,    actions: {        foo: s => s // Should be typed number => number    },    view: (s, a) => undefined as any,}) : void
+>app2 : <State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>) => void
+>{    state: 100,    actions: {        foo: s => s // Should be typed number => number    },    view: (s, a) => undefined as any,} : { state: number; actions: { foo: (s: number) => number; }; view: (s: number, a: ActionsObject<number>) => any; }
+
+    state: 100,
+>state : number
+>100 : 100
+
+    actions: {
+>actions : { foo: (s: number) => number; }
+>{        foo: s => s // Should be typed number => number    } : { foo: (s: number) => number; }
+
+        foo: s => s // Should be typed number => number
+>foo : (s: number) => number
+>s => s : (s: number) => number
+>s : number
+>s : number
+
+    },
+    view: (s, a) => undefined as any,
+>view : (s: number, a: ActionsObject<number>) => any
+>(s, a) => undefined as any : (s: number, a: ActionsObject<number>) => any
+>s : number
+>a : ActionsObject<number>
+>undefined as any : any
+>undefined : undefined
+
+});
+
+
+type ActionsArray<State> = ((state: State) => State)[];
+>ActionsArray : ((state: State) => State)[]
+>State : State
+>state : State
+>State : State
+>State : State
+
+declare function app3<State, Actions extends ActionsArray<State>>(obj: Options<State, Actions>): void;
+>app3 : <State, Actions extends ((state: State) => State)[]>(obj: Options<State, Actions>) => void
+>State : State
+>Actions : Actions
+>ActionsArray : ((state: State) => State)[]
+>State : State
+>obj : Options<State, Actions>
+>Options : Options<State, Actions>
+>State : State
+>Actions : Actions
+
+app3({
+>app3({    state: 100,    actions: [        s => s // Should be typed number => number    ],    view: (s, a) => undefined as any,}) : void
+>app3 : <State, Actions extends ((state: State) => State)[]>(obj: Options<State, Actions>) => void
+>{    state: 100,    actions: [        s => s // Should be typed number => number    ],    view: (s, a) => undefined as any,} : { state: number; actions: ((s: number) => number)[]; view: (s: number, a: ((state: number) => number)[]) => any; }
+
+    state: 100,
+>state : number
+>100 : 100
+
+    actions: [
+>actions : ((s: number) => number)[]
+>[        s => s // Should be typed number => number    ] : ((s: number) => number)[]
+
+        s => s // Should be typed number => number
+>s => s : (s: number) => number
+>s : number
+>s : number
+
+    ],
+    view: (s, a) => undefined as any,
+>view : (s: number, a: ((state: number) => number)[]) => any
+>(s, a) => undefined as any : (s: number, a: ((state: number) => number)[]) => any
+>s : number
+>a : ((state: number) => number)[]
+>undefined as any : any
+>undefined : undefined
+
+});
+
+namespace JSX {
+>JSX : any
+
+    export interface Element {}
+>Element : Element
+
+    export interface IntrinsicElements {}
+>IntrinsicElements : IntrinsicElements
+}
+
+interface ActionsObjectOr<State> {
+>ActionsObjectOr : ActionsObjectOr<State>
+>State : State
+
+    [prop: string]: ((state: State) => State) | State;
+>prop : string
+>state : State
+>State : State
+>State : State
+>State : State
+}
+
+declare function App4<State, Actions extends ActionsObjectOr<State>>(props: Options<State, Actions>["actions"] & { state: State }): JSX.Element;
+>App4 : <State, Actions extends ActionsObjectOr<State>>(props: (string & { state: State; }) | (Actions & { state: State; })) => JSX.Element
+>State : State
+>Actions : Actions
+>ActionsObjectOr : ActionsObjectOr<State>
+>State : State
+>props : (string & { state: State; }) | (Actions & { state: State; })
+>Options : Options<State, Actions>
+>State : State
+>Actions : Actions
+>state : State
+>State : State
+>JSX : any
+>Element : JSX.Element
+
+const a = <App4 state={100} foo={s => s} />; // TODO: should be number => number, but JSX resolution is missing an inferential pass
+>a : JSX.Element
+><App4 state={100} foo={s => s} /> : JSX.Element
+>App4 : <State, Actions extends ActionsObjectOr<State>>(props: (string & { state: State; }) | (Actions & { state: State; })) => JSX.Element
+>state : number
+>100 : 100
+>foo : (s: any) => any
+>s => s : (s: any) => any
+>s : any
+>s : any
+
diff --git a/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.js b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.js
new file mode 100644
index 00000000000..b61c235dee9
--- /dev/null
+++ b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.js
@@ -0,0 +1,42 @@
+//// [contextuallyTypedByDiscriminableUnion.ts]
+type ADT = {
+    kind: "a",
+    method(x: string): number;
+} | {
+    kind: "b",
+    method(x: number): string;
+};
+
+
+function invoke(item: ADT) {
+    if (item.kind === "a") {
+        item.method("");
+    }
+    else {
+        item.method(42);
+    }
+}
+
+invoke({
+    kind: "a",
+    method(a) {
+        return +a;
+    }
+});
+
+
+//// [contextuallyTypedByDiscriminableUnion.js]
+function invoke(item) {
+    if (item.kind === "a") {
+        item.method("");
+    }
+    else {
+        item.method(42);
+    }
+}
+invoke({
+    kind: "a",
+    method: function (a) {
+        return +a;
+    }
+});
diff --git a/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.symbols b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.symbols
new file mode 100644
index 00000000000..e4ef8ee73e7
--- /dev/null
+++ b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.symbols
@@ -0,0 +1,60 @@
+=== tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts ===
+type ADT = {
+>ADT : Symbol(ADT, Decl(contextuallyTypedByDiscriminableUnion.ts, 0, 0))
+
+    kind: "a",
+>kind : Symbol(kind, Decl(contextuallyTypedByDiscriminableUnion.ts, 0, 12))
+
+    method(x: string): number;
+>method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 1, 14))
+>x : Symbol(x, Decl(contextuallyTypedByDiscriminableUnion.ts, 2, 11))
+
+} | {
+    kind: "b",
+>kind : Symbol(kind, Decl(contextuallyTypedByDiscriminableUnion.ts, 3, 5))
+
+    method(x: number): string;
+>method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 4, 14))
+>x : Symbol(x, Decl(contextuallyTypedByDiscriminableUnion.ts, 5, 11))
+
+};
+
+
+function invoke(item: ADT) {
+>invoke : Symbol(invoke, Decl(contextuallyTypedByDiscriminableUnion.ts, 6, 2))
+>item : Symbol(item, Decl(contextuallyTypedByDiscriminableUnion.ts, 9, 16))
+>ADT : Symbol(ADT, Decl(contextuallyTypedByDiscriminableUnion.ts, 0, 0))
+
+    if (item.kind === "a") {
+>item.kind : Symbol(kind, Decl(contextuallyTypedByDiscriminableUnion.ts, 0, 12), Decl(contextuallyTypedByDiscriminableUnion.ts, 3, 5))
+>item : Symbol(item, Decl(contextuallyTypedByDiscriminableUnion.ts, 9, 16))
+>kind : Symbol(kind, Decl(contextuallyTypedByDiscriminableUnion.ts, 0, 12), Decl(contextuallyTypedByDiscriminableUnion.ts, 3, 5))
+
+        item.method("");
+>item.method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 1, 14))
+>item : Symbol(item, Decl(contextuallyTypedByDiscriminableUnion.ts, 9, 16))
+>method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 1, 14))
+    }
+    else {
+        item.method(42);
+>item.method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 4, 14))
+>item : Symbol(item, Decl(contextuallyTypedByDiscriminableUnion.ts, 9, 16))
+>method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 4, 14))
+    }
+}
+
+invoke({
+>invoke : Symbol(invoke, Decl(contextuallyTypedByDiscriminableUnion.ts, 6, 2))
+
+    kind: "a",
+>kind : Symbol(kind, Decl(contextuallyTypedByDiscriminableUnion.ts, 18, 8))
+
+    method(a) {
+>method : Symbol(method, Decl(contextuallyTypedByDiscriminableUnion.ts, 19, 14))
+>a : Symbol(a, Decl(contextuallyTypedByDiscriminableUnion.ts, 20, 11))
+
+        return +a;
+>a : Symbol(a, Decl(contextuallyTypedByDiscriminableUnion.ts, 20, 11))
+    }
+});
+
diff --git a/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.types b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.types
new file mode 100644
index 00000000000..d62dc4b5e0c
--- /dev/null
+++ b/tests/baselines/reference/contextuallyTypedByDiscriminableUnion.types
@@ -0,0 +1,70 @@
+=== tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts ===
+type ADT = {
+>ADT : ADT
+
+    kind: "a",
+>kind : "a"
+
+    method(x: string): number;
+>method : (x: string) => number
+>x : string
+
+} | {
+    kind: "b",
+>kind : "b"
+
+    method(x: number): string;
+>method : (x: number) => string
+>x : number
+
+};
+
+
+function invoke(item: ADT) {
+>invoke : (item: ADT) => void
+>item : ADT
+>ADT : ADT
+
+    if (item.kind === "a") {
+>item.kind === "a" : boolean
+>item.kind : "a" | "b"
+>item : ADT
+>kind : "a" | "b"
+>"a" : "a"
+
+        item.method("");
+>item.method("") : number
+>item.method : (x: string) => number
+>item : { kind: "a"; method(x: string): number; }
+>method : (x: string) => number
+>"" : ""
+    }
+    else {
+        item.method(42);
+>item.method(42) : string
+>item.method : (x: number) => string
+>item : { kind: "b"; method(x: number): string; }
+>method : (x: number) => string
+>42 : 42
+    }
+}
+
+invoke({
+>invoke({    kind: "a",    method(a) {        return +a;    }}) : void
+>invoke : (item: ADT) => void
+>{    kind: "a",    method(a) {        return +a;    }} : { kind: "a"; method(a: string): number; }
+
+    kind: "a",
+>kind : string
+>"a" : "a"
+
+    method(a) {
+>method : (a: string) => number
+>a : string
+
+        return +a;
+>+a : number
+>a : string
+    }
+});
+
diff --git a/tests/baselines/reference/controlFlowStringIndex.js b/tests/baselines/reference/controlFlowStringIndex.js
new file mode 100644
index 00000000000..db4d4a30ab9
--- /dev/null
+++ b/tests/baselines/reference/controlFlowStringIndex.js
@@ -0,0 +1,20 @@
+//// [controlFlowStringIndex.ts]
+type A = {
+    other: number | null;
+    [index: string]: number | null
+};
+declare const value: A;
+if (value.foo !== null) {
+    value.foo.toExponential()
+    value.other // should still be number | null
+    value.bar // should still be number | null
+}
+
+
+//// [controlFlowStringIndex.js]
+"use strict";
+if (value.foo !== null) {
+    value.foo.toExponential();
+    value.other; // should still be number | null
+    value.bar; // should still be number | null
+}
diff --git a/tests/baselines/reference/controlFlowStringIndex.symbols b/tests/baselines/reference/controlFlowStringIndex.symbols
new file mode 100644
index 00000000000..5c7d626d4a7
--- /dev/null
+++ b/tests/baselines/reference/controlFlowStringIndex.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/conformance/controlFlow/controlFlowStringIndex.ts ===
+type A = {
+>A : Symbol(A, Decl(controlFlowStringIndex.ts, 0, 0))
+
+    other: number | null;
+>other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
+
+    [index: string]: number | null
+>index : Symbol(index, Decl(controlFlowStringIndex.ts, 2, 5))
+
+};
+declare const value: A;
+>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
+>A : Symbol(A, Decl(controlFlowStringIndex.ts, 0, 0))
+
+if (value.foo !== null) {
+>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
+
+    value.foo.toExponential()
+>value.foo.toExponential : Symbol(Number.toExponential, Decl(lib.d.ts, --, --))
+>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
+>toExponential : Symbol(Number.toExponential, Decl(lib.d.ts, --, --))
+
+    value.other // should still be number | null
+>value.other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
+>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
+>other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
+
+    value.bar // should still be number | null
+>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
+}
+
diff --git a/tests/baselines/reference/controlFlowStringIndex.types b/tests/baselines/reference/controlFlowStringIndex.types
new file mode 100644
index 00000000000..8c5f82cbf80
--- /dev/null
+++ b/tests/baselines/reference/controlFlowStringIndex.types
@@ -0,0 +1,43 @@
+=== tests/cases/conformance/controlFlow/controlFlowStringIndex.ts ===
+type A = {
+>A : A
+
+    other: number | null;
+>other : number | null
+>null : null
+
+    [index: string]: number | null
+>index : string
+>null : null
+
+};
+declare const value: A;
+>value : A
+>A : A
+
+if (value.foo !== null) {
+>value.foo !== null : boolean
+>value.foo : number | null
+>value : A
+>foo : number | null
+>null : null
+
+    value.foo.toExponential()
+>value.foo.toExponential() : string
+>value.foo.toExponential : (fractionDigits?: number | undefined) => string
+>value.foo : number
+>value : A
+>foo : number
+>toExponential : (fractionDigits?: number | undefined) => string
+
+    value.other // should still be number | null
+>value.other : number | null
+>value : A
+>other : number | null
+
+    value.bar // should still be number | null
+>value.bar : number | null
+>value : A
+>bar : number | null
+}
+
diff --git a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.errors.txt b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.errors.txt
index 771960ba788..4ea18c15901 100644
--- a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.errors.txt
+++ b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.errors.txt
@@ -1,13 +1,13 @@
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(15,21): error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(20,13): error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(25,25): error TS4037: Parameter 'foo3' of public property setter from exported class has or is using private name 'private1'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(32,25): error TS4037: Parameter 'foo4' of public property setter from exported class has or is using private name 'private1'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(36,21): error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(71,23): error TS4043: Return type of public property getter from exported class has or is using private name 'm2'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(76,13): error TS4042: Return type of public property getter from exported class has or is using name 'm2.public2' from private module 'm2'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(81,27): error TS4037: Parameter 'foo113' of public property setter from exported class has or is using private name 'm2'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(88,27): error TS4037: Parameter 'foo114' of public property setter from exported class has or is using private name 'm2'.
-tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): error TS4043: Return type of public property getter from exported class has or is using private name 'm2'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(15,21): error TS4043: Return type of public getter 'foo1' from exported class has or is using private name 'private1'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(20,13): error TS4043: Return type of public getter 'foo2' from exported class has or is using private name 'private1'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(25,25): error TS4037: Parameter type of public setter 'foo3' from exported class has or is using private name 'private1'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(32,25): error TS4037: Parameter type of public setter 'foo4' from exported class has or is using private name 'private1'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(36,21): error TS4043: Return type of public getter 'foo5' from exported class has or is using private name 'private1'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(71,23): error TS4043: Return type of public getter 'foo111' from exported class has or is using private name 'm2'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(76,13): error TS4042: Return type of public getter 'foo112' from exported class has or is using name 'm2.public2' from private module 'm2'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(81,27): error TS4037: Parameter type of public setter 'foo113' from exported class has or is using private name 'm2'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(88,27): error TS4037: Parameter type of public setter 'foo114' from exported class has or is using private name 'm2'.
+tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): error TS4043: Return type of public getter 'foo115' from exported class has or is using private name 'm2'.
 
 
 ==== tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts (10 errors) ====
@@ -22,26 +22,26 @@ tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): e
             export class public2 {
             }
         }
-        
+    
         export class c {
             // getter with annotation
             get foo1(): private1 {
                         ~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
+!!! error TS4043: Return type of public getter 'foo1' from exported class has or is using private name 'private1'.
                 return;
             }
     
             // getter without annotation
             get foo2() {
                 ~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
+!!! error TS4043: Return type of public getter 'foo2' from exported class has or is using private name 'private1'.
                 return new private1();
             }
     
             // setter with annotation
             set foo3(param: private1) {
                             ~~~~~~~~
-!!! error TS4037: Parameter 'foo3' of public property setter from exported class has or is using private name 'private1'.
+!!! error TS4037: Parameter type of public setter 'foo3' from exported class has or is using private name 'private1'.
             }
     
             // Both - getter without annotation, setter with annotation
@@ -50,18 +50,18 @@ tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): e
             }
             set foo4(param: private1) {
                             ~~~~~~~~
-!!! error TS4037: Parameter 'foo4' of public property setter from exported class has or is using private name 'private1'.
+!!! error TS4037: Parameter type of public setter 'foo4' from exported class has or is using private name 'private1'.
             }
     
             // Both - with annotation
             get foo5(): private1 {
                         ~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'private1'.
+!!! error TS4043: Return type of public getter 'foo5' from exported class has or is using private name 'private1'.
                 return;
             }
             set foo5(param: private1) {
             }
-        
+    
             // getter with annotation
             get foo11(): public1 {
                 return;
@@ -93,21 +93,21 @@ tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): e
             // getter with annotation
             get foo111(): m2.public2 {
                           ~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'm2'.
+!!! error TS4043: Return type of public getter 'foo111' from exported class has or is using private name 'm2'.
                 return;
             }
     
             // getter without annotation
             get foo112() {
                 ~~~~~~
-!!! error TS4042: Return type of public property getter from exported class has or is using name 'm2.public2' from private module 'm2'.
+!!! error TS4042: Return type of public getter 'foo112' from exported class has or is using name 'm2.public2' from private module 'm2'.
                 return new m2.public2();
             }
     
             // setter with annotation
             set foo113(param: m2.public2) {
                               ~~
-!!! error TS4037: Parameter 'foo113' of public property setter from exported class has or is using private name 'm2'.
+!!! error TS4037: Parameter type of public setter 'foo113' from exported class has or is using private name 'm2'.
             }
     
             // Both - getter without annotation, setter with annotation
@@ -116,13 +116,13 @@ tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts(92,23): e
             }
             set foo114(param: m2.public2) {
                               ~~
-!!! error TS4037: Parameter 'foo114' of public property setter from exported class has or is using private name 'm2'.
+!!! error TS4037: Parameter type of public setter 'foo114' from exported class has or is using private name 'm2'.
             }
     
             // Both - with annotation
             get foo115(): m2.public2 {
                           ~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'm2'.
+!!! error TS4043: Return type of public getter 'foo115' from exported class has or is using private name 'm2'.
                 return;
             }
             set foo115(param: m2.public2) {
diff --git a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.js b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.js
index 2d4d948668a..c02807207ca 100644
--- a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.js
+++ b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.js
@@ -10,7 +10,7 @@ module m {
         export class public2 {
         }
     }
-    
+
     export class c {
         // getter with annotation
         get foo1(): private1 {
@@ -39,7 +39,7 @@ module m {
         }
         set foo5(param: private1) {
         }
-    
+
         // getter with annotation
         get foo11(): public1 {
             return;
diff --git a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.symbols b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.symbols
index 503fa75ff97..25b8adca4ac 100644
--- a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.symbols
+++ b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.symbols
@@ -17,7 +17,7 @@ module m {
 >public2 : Symbol(public2, Decl(declFileTypeAnnotationVisibilityErrorAccessors.ts, 7, 15))
         }
     }
-    
+
     export class c {
 >c : Symbol(c, Decl(declFileTypeAnnotationVisibilityErrorAccessors.ts, 10, 5))
 
@@ -69,7 +69,7 @@ module m {
 >param : Symbol(param, Decl(declFileTypeAnnotationVisibilityErrorAccessors.ts, 38, 17))
 >private1 : Symbol(private1, Decl(declFileTypeAnnotationVisibilityErrorAccessors.ts, 0, 10))
         }
-    
+
         // getter with annotation
         get foo11(): public1 {
 >foo11 : Symbol(c.foo11, Decl(declFileTypeAnnotationVisibilityErrorAccessors.ts, 39, 9))
diff --git a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.types b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.types
index c82794f2764..a05a00908d2 100644
--- a/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.types
+++ b/tests/baselines/reference/declFileTypeAnnotationVisibilityErrorAccessors.types
@@ -17,7 +17,7 @@ module m {
 >public2 : public2
         }
     }
-    
+
     export class c {
 >c : c
 
@@ -71,7 +71,7 @@ module m {
 >param : private1
 >private1 : private1
         }
-    
+
         // getter with annotation
         get foo11(): public1 {
 >foo11 : public1
diff --git a/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.js b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.js
new file mode 100644
index 00000000000..5f1f5743201
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.js
@@ -0,0 +1,35 @@
+//// [tests/cases/compiler/declarationEmitOfTypeofAliasedExport.ts] ////
+
+//// [a.ts]
+class C {}
+export { C as D }
+
+//// [b.ts]
+import * as a from "./a";
+export default a.D;
+
+
+//// [a.js]
+"use strict";
+exports.__esModule = true;
+var C = /** @class */ (function () {
+    function C() {
+    }
+    return C;
+}());
+exports.D = C;
+//// [b.js]
+"use strict";
+exports.__esModule = true;
+var a = require("./a");
+exports["default"] = a.D;
+
+
+//// [a.d.ts]
+declare class C {
+}
+export { C as D };
+//// [b.d.ts]
+import * as a from "./a";
+declare const _default: typeof a.D;
+export default _default;
diff --git a/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.symbols b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.symbols
new file mode 100644
index 00000000000..d13d242105b
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.symbols
@@ -0,0 +1,17 @@
+=== /a.ts ===
+class C {}
+>C : Symbol(C, Decl(a.ts, 0, 0))
+
+export { C as D }
+>C : Symbol(D, Decl(a.ts, 1, 8))
+>D : Symbol(D, Decl(a.ts, 1, 8))
+
+=== /b.ts ===
+import * as a from "./a";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+
+export default a.D;
+>a.D : Symbol(a.D, Decl(a.ts, 1, 8))
+>a : Symbol(a, Decl(b.ts, 0, 6))
+>D : Symbol(a.D, Decl(a.ts, 1, 8))
+
diff --git a/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.types b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.types
new file mode 100644
index 00000000000..ccd13107166
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitOfTypeofAliasedExport.types
@@ -0,0 +1,17 @@
+=== /a.ts ===
+class C {}
+>C : C
+
+export { C as D }
+>C : typeof C
+>D : typeof C
+
+=== /b.ts ===
+import * as a from "./a";
+>a : typeof a
+
+export default a.D;
+>a.D : typeof a.D
+>a : typeof a
+>D : typeof a.D
+
diff --git a/tests/baselines/reference/declarationEmitRelativeModuleError.errors.txt b/tests/baselines/reference/declarationEmitRelativeModuleError.errors.txt
new file mode 100644
index 00000000000..32aea83b5e4
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitRelativeModuleError.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/declarationEmitRelativeModuleError.ts(5,16): error TS2436: Ambient module declaration cannot specify relative module name.
+
+
+==== tests/cases/compiler/declarationEmitRelativeModuleError.ts (1 errors) ====
+    declare module "b:block" { // <-- no error anymore
+        
+    }
+    
+    declare module "b:/block" { // <-- still an error
+                   ~~~~~~~~~~
+!!! error TS2436: Ambient module declaration cannot specify relative module name.
+        
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitRelativeModuleError.js b/tests/baselines/reference/declarationEmitRelativeModuleError.js
new file mode 100644
index 00000000000..e1d78ba5c03
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitRelativeModuleError.js
@@ -0,0 +1,10 @@
+//// [declarationEmitRelativeModuleError.ts]
+declare module "b:block" { // <-- no error anymore
+    
+}
+
+declare module "b:/block" { // <-- still an error
+    
+}
+
+//// [declarationEmitRelativeModuleError.js]
diff --git a/tests/baselines/reference/declarationEmitRelativeModuleError.symbols b/tests/baselines/reference/declarationEmitRelativeModuleError.symbols
new file mode 100644
index 00000000000..d07a145116a
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitRelativeModuleError.symbols
@@ -0,0 +1,9 @@
+=== tests/cases/compiler/declarationEmitRelativeModuleError.ts ===
+declare module "b:block" { // <-- no error anymore
+No type information for this code.    
+No type information for this code.}
+No type information for this code.
+No type information for this code.declare module "b:/block" { // <-- still an error
+No type information for this code.    
+No type information for this code.}
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitRelativeModuleError.types b/tests/baselines/reference/declarationEmitRelativeModuleError.types
new file mode 100644
index 00000000000..d07a145116a
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitRelativeModuleError.types
@@ -0,0 +1,9 @@
+=== tests/cases/compiler/declarationEmitRelativeModuleError.ts ===
+declare module "b:block" { // <-- no error anymore
+No type information for this code.    
+No type information for this code.}
+No type information for this code.
+No type information for this code.declare module "b:/block" { // <-- still an error
+No type information for this code.    
+No type information for this code.}
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/declarationEmitTypeofDefaultExport.js b/tests/baselines/reference/declarationEmitTypeofDefaultExport.js
new file mode 100644
index 00000000000..c4a105ca8b9
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeofDefaultExport.js
@@ -0,0 +1,34 @@
+//// [tests/cases/compiler/declarationEmitTypeofDefaultExport.ts] ////
+
+//// [a.ts]
+export default class C {};
+
+//// [b.ts]
+import * as a from "./a";
+export default a.default;
+
+
+//// [a.js]
+"use strict";
+exports.__esModule = true;
+var C = /** @class */ (function () {
+    function C() {
+    }
+    return C;
+}());
+exports["default"] = C;
+;
+//// [b.js]
+"use strict";
+exports.__esModule = true;
+var a = require("./a");
+exports["default"] = a["default"];
+
+
+//// [a.d.ts]
+export default class C {
+}
+//// [b.d.ts]
+import * as a from "./a";
+declare const _default: typeof a.default;
+export default _default;
diff --git a/tests/baselines/reference/declarationEmitTypeofDefaultExport.symbols b/tests/baselines/reference/declarationEmitTypeofDefaultExport.symbols
new file mode 100644
index 00000000000..195f10a78a1
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeofDefaultExport.symbols
@@ -0,0 +1,13 @@
+=== /a.ts ===
+export default class C {};
+>C : Symbol(C, Decl(a.ts, 0, 0))
+
+=== /b.ts ===
+import * as a from "./a";
+>a : Symbol(a, Decl(b.ts, 0, 6))
+
+export default a.default;
+>a.default : Symbol(a.default, Decl(a.ts, 0, 0))
+>a : Symbol(a, Decl(b.ts, 0, 6))
+>default : Symbol(a.default, Decl(a.ts, 0, 0))
+
diff --git a/tests/baselines/reference/declarationEmitTypeofDefaultExport.types b/tests/baselines/reference/declarationEmitTypeofDefaultExport.types
new file mode 100644
index 00000000000..9cdd56d0cfb
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitTypeofDefaultExport.types
@@ -0,0 +1,13 @@
+=== /a.ts ===
+export default class C {};
+>C : C
+
+=== /b.ts ===
+import * as a from "./a";
+>a : typeof a
+
+export default a.default;
+>a.default : typeof a.C
+>a : typeof a
+>default : typeof a.C
+
diff --git a/tests/baselines/reference/decoratorOnClassMethod13.js b/tests/baselines/reference/decoratorOnClassMethod13.js
index adf21f733eb..e8a913070fc 100644
--- a/tests/baselines/reference/decoratorOnClassMethod13.js
+++ b/tests/baselines/reference/decoratorOnClassMethod13.js
@@ -14,13 +14,12 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
 class C {
-    [_a = "1"]() { }
-    [_b = "b"]() { }
+    ["1"]() { }
+    ["b"]() { }
 }
 __decorate([
     dec
-], C.prototype, _a, null);
+], C.prototype, "1", null);
 __decorate([
     dec
-], C.prototype, _b, null);
-var _a, _b;
+], C.prototype, "b", null);
diff --git a/tests/baselines/reference/decoratorOnClassMethod4.js b/tests/baselines/reference/decoratorOnClassMethod4.js
index 5c7b91c1c83..c68cca5d3a0 100644
--- a/tests/baselines/reference/decoratorOnClassMethod4.js
+++ b/tests/baselines/reference/decoratorOnClassMethod4.js
@@ -13,9 +13,8 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
 class C {
-    [_a = "method"]() { }
+    ["method"]() { }
 }
 __decorate([
     dec
-], C.prototype, _a, null);
-var _a;
+], C.prototype, "method", null);
diff --git a/tests/baselines/reference/decoratorOnClassMethod5.js b/tests/baselines/reference/decoratorOnClassMethod5.js
index 2fedbaaf764..c89ebc6bb38 100644
--- a/tests/baselines/reference/decoratorOnClassMethod5.js
+++ b/tests/baselines/reference/decoratorOnClassMethod5.js
@@ -13,9 +13,8 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
 class C {
-    [_a = "method"]() { }
+    ["method"]() { }
 }
 __decorate([
     dec()
-], C.prototype, _a, null);
-var _a;
+], C.prototype, "method", null);
diff --git a/tests/baselines/reference/decoratorOnClassMethod6.js b/tests/baselines/reference/decoratorOnClassMethod6.js
index 7966225e221..45f5eeddb81 100644
--- a/tests/baselines/reference/decoratorOnClassMethod6.js
+++ b/tests/baselines/reference/decoratorOnClassMethod6.js
@@ -13,9 +13,8 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
 class C {
-    [_a = "method"]() { }
+    ["method"]() { }
 }
 __decorate([
     dec
-], C.prototype, _a, null);
-var _a;
+], C.prototype, "method", null);
diff --git a/tests/baselines/reference/decoratorOnClassMethod7.js b/tests/baselines/reference/decoratorOnClassMethod7.js
index 3ec509e17f0..dc92364cd89 100644
--- a/tests/baselines/reference/decoratorOnClassMethod7.js
+++ b/tests/baselines/reference/decoratorOnClassMethod7.js
@@ -13,9 +13,8 @@ var __decorate = (this && this.__decorate) || function (decorators, target, key,
     return c > 3 && r && Object.defineProperty(target, key, r), r;
 };
 class C {
-    [_a = "method"]() { }
+    ["method"]() { }
 }
 __decorate([
     dec
-], C.prototype, _a, null);
-var _a;
+], C.prototype, "method", null);
diff --git a/tests/baselines/reference/decoratorReferenceOnOtherProperty.js b/tests/baselines/reference/decoratorReferenceOnOtherProperty.js
new file mode 100644
index 00000000000..6313f339ba9
--- /dev/null
+++ b/tests/baselines/reference/decoratorReferenceOnOtherProperty.js
@@ -0,0 +1,109 @@
+//// [tests/cases/compiler/decoratorReferenceOnOtherProperty.ts] ////
+
+//// [yoha.ts]
+// https://github.com/Microsoft/TypeScript/issues/19799
+export class Yoha {}
+
+//// [index.ts]
+import {Yoha} from './yoha';
+
+function foo(...args: any[]) {}
+
+class Bar {
+  yoha(@foo yoha, bar: Yoha) {}
+  //                   ^^^^
+}
+
+//// [index2.ts]
+import {Yoha} from './yoha';
+
+function foo(...args: any[]) {}
+
+class Bar {
+  yoha(@foo yoha, ...bar: Yoha[]) {}
+  //                      ^^^^
+}
+
+//// [yoha.js]
+"use strict";
+exports.__esModule = true;
+// https://github.com/Microsoft/TypeScript/issues/19799
+var Yoha = /** @class */ (function () {
+    function Yoha() {
+    }
+    return Yoha;
+}());
+exports.Yoha = Yoha;
+//// [index.js]
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+var __param = (this && this.__param) || function (paramIndex, decorator) {
+    return function (target, key) { decorator(target, key, paramIndex); }
+};
+exports.__esModule = true;
+var yoha_1 = require("./yoha");
+function foo() {
+    var args = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        args[_i] = arguments[_i];
+    }
+}
+var Bar = /** @class */ (function () {
+    function Bar() {
+    }
+    Bar.prototype.yoha = function (yoha, bar) { };
+    __decorate([
+        __param(0, foo),
+        __metadata("design:type", Function),
+        __metadata("design:paramtypes", [Object, yoha_1.Yoha]),
+        __metadata("design:returntype", void 0)
+    ], Bar.prototype, "yoha");
+    return Bar;
+}());
+//// [index2.js]
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+var __param = (this && this.__param) || function (paramIndex, decorator) {
+    return function (target, key) { decorator(target, key, paramIndex); }
+};
+exports.__esModule = true;
+var yoha_1 = require("./yoha");
+function foo() {
+    var args = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        args[_i] = arguments[_i];
+    }
+}
+var Bar = /** @class */ (function () {
+    function Bar() {
+    }
+    Bar.prototype.yoha = function (yoha) {
+        var bar = [];
+        for (var _i = 1; _i < arguments.length; _i++) {
+            bar[_i - 1] = arguments[_i];
+        }
+    };
+    __decorate([
+        __param(0, foo),
+        __metadata("design:type", Function),
+        __metadata("design:paramtypes", [Object, yoha_1.Yoha]),
+        __metadata("design:returntype", void 0)
+    ], Bar.prototype, "yoha");
+    return Bar;
+}());
diff --git a/tests/baselines/reference/decoratorReferenceOnOtherProperty.symbols b/tests/baselines/reference/decoratorReferenceOnOtherProperty.symbols
new file mode 100644
index 00000000000..619e2afe4e9
--- /dev/null
+++ b/tests/baselines/reference/decoratorReferenceOnOtherProperty.symbols
@@ -0,0 +1,46 @@
+=== tests/cases/compiler/yoha.ts ===
+// https://github.com/Microsoft/TypeScript/issues/19799
+export class Yoha {}
+>Yoha : Symbol(Yoha, Decl(yoha.ts, 0, 0))
+
+=== tests/cases/compiler/index.ts ===
+import {Yoha} from './yoha';
+>Yoha : Symbol(Yoha, Decl(index.ts, 0, 8))
+
+function foo(...args: any[]) {}
+>foo : Symbol(foo, Decl(index.ts, 0, 28))
+>args : Symbol(args, Decl(index.ts, 2, 13))
+
+class Bar {
+>Bar : Symbol(Bar, Decl(index.ts, 2, 31))
+
+  yoha(@foo yoha, bar: Yoha) {}
+>yoha : Symbol(Bar.yoha, Decl(index.ts, 4, 11))
+>foo : Symbol(foo, Decl(index.ts, 0, 28))
+>yoha : Symbol(yoha, Decl(index.ts, 5, 7))
+>bar : Symbol(bar, Decl(index.ts, 5, 17))
+>Yoha : Symbol(Yoha, Decl(index.ts, 0, 8))
+
+  //                   ^^^^
+}
+
+=== tests/cases/compiler/index2.ts ===
+import {Yoha} from './yoha';
+>Yoha : Symbol(Yoha, Decl(index2.ts, 0, 8))
+
+function foo(...args: any[]) {}
+>foo : Symbol(foo, Decl(index2.ts, 0, 28))
+>args : Symbol(args, Decl(index2.ts, 2, 13))
+
+class Bar {
+>Bar : Symbol(Bar, Decl(index2.ts, 2, 31))
+
+  yoha(@foo yoha, ...bar: Yoha[]) {}
+>yoha : Symbol(Bar.yoha, Decl(index2.ts, 4, 11))
+>foo : Symbol(foo, Decl(index2.ts, 0, 28))
+>yoha : Symbol(yoha, Decl(index2.ts, 5, 7))
+>bar : Symbol(bar, Decl(index2.ts, 5, 17))
+>Yoha : Symbol(Yoha, Decl(index2.ts, 0, 8))
+
+  //                      ^^^^
+}
diff --git a/tests/baselines/reference/decoratorReferenceOnOtherProperty.types b/tests/baselines/reference/decoratorReferenceOnOtherProperty.types
new file mode 100644
index 00000000000..5994657aa31
--- /dev/null
+++ b/tests/baselines/reference/decoratorReferenceOnOtherProperty.types
@@ -0,0 +1,46 @@
+=== tests/cases/compiler/yoha.ts ===
+// https://github.com/Microsoft/TypeScript/issues/19799
+export class Yoha {}
+>Yoha : Yoha
+
+=== tests/cases/compiler/index.ts ===
+import {Yoha} from './yoha';
+>Yoha : typeof Yoha
+
+function foo(...args: any[]) {}
+>foo : (...args: any[]) => void
+>args : any[]
+
+class Bar {
+>Bar : Bar
+
+  yoha(@foo yoha, bar: Yoha) {}
+>yoha : (yoha: any, bar: Yoha) => void
+>foo : (...args: any[]) => void
+>yoha : any
+>bar : Yoha
+>Yoha : Yoha
+
+  //                   ^^^^
+}
+
+=== tests/cases/compiler/index2.ts ===
+import {Yoha} from './yoha';
+>Yoha : typeof Yoha
+
+function foo(...args: any[]) {}
+>foo : (...args: any[]) => void
+>args : any[]
+
+class Bar {
+>Bar : Bar
+
+  yoha(@foo yoha, ...bar: Yoha[]) {}
+>yoha : (yoha: any, ...bar: Yoha[]) => void
+>foo : (...args: any[]) => void
+>yoha : any
+>bar : Yoha[]
+>Yoha : Yoha
+
+  //                      ^^^^
+}
diff --git a/tests/baselines/reference/decoratorsOnComputedProperties.errors.txt b/tests/baselines/reference/decoratorsOnComputedProperties.errors.txt
new file mode 100644
index 00000000000..2aef827d4f5
--- /dev/null
+++ b/tests/baselines/reference/decoratorsOnComputedProperties.errors.txt
@@ -0,0 +1,435 @@
+tests/cases/compiler/decoratorsOnComputedProperties.ts(18,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(19,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(20,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(21,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(22,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(23,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(27,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(28,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(29,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(30,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(35,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(36,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(37,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(38,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(39,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(40,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(52,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(53,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(54,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(55,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(56,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(57,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(62,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(63,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(64,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(65,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(70,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(71,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(72,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(73,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(74,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(75,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(88,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(89,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(90,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(92,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(93,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(94,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(98,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(99,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(100,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(101,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(106,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(107,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(108,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(110,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(111,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(112,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(124,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(125,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(126,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(128,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(129,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(131,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(135,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(136,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(137,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(138,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(143,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(144,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(145,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(147,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(148,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(150,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(162,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(163,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(164,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(166,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(167,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(169,8): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(173,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(174,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(175,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(176,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(181,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(182,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(183,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(184,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(185,5): error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(186,5): error TS1206: Decorators are not valid here.
+tests/cases/compiler/decoratorsOnComputedProperties.ts(188,5): error TS1206: Decorators are not valid here.
+
+
+==== tests/cases/compiler/decoratorsOnComputedProperties.ts (81 errors) ====
+    function x(o: object, k: PropertyKey) { }
+    let i = 0;
+    function foo(): string { return ++i + ""; }
+    
+    const fieldNameA: string = "fieldName1";
+    const fieldNameB: string = "fieldName2";
+    const fieldNameC: string = "fieldName3";
+    
+    class A {
+        @x ["property"]: any;
+        @x [Symbol.toStringTag]: any;
+        @x ["property2"]: any = 2;
+        @x [Symbol.iterator]: any = null;
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any = null;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameC]: any = null;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+    }
+    
+    void class B {
+        @x ["property"]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.toStringTag]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["property2"]: any = 2;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.iterator]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [foo()]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [fieldNameC]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+    };
+    
+    class C {
+        @x ["property"]: any;
+        @x [Symbol.toStringTag]: any;
+        @x ["property2"]: any = 2;
+        @x [Symbol.iterator]: any = null;
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any = null;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameC]: any = null;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        ["some" + "method"]() {}
+    }
+    
+    void class D {
+        @x ["property"]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.toStringTag]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["property2"]: any = 2;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.iterator]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [foo()]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [fieldNameC]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["some" + "method"]() {}
+    };
+    
+    class E {
+        @x ["property"]: any;
+        @x [Symbol.toStringTag]: any;
+        @x ["property2"]: any = 2;
+        @x [Symbol.iterator]: any = null;
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any = null;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        ["some" + "method"]() {}
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameC]: any = null;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+    }
+    
+    void class F {
+        @x ["property"]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.toStringTag]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["property2"]: any = 2;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.iterator]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [foo()]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["some" + "method"]() {}
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [fieldNameC]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+    };
+    
+    class G {
+        @x ["property"]: any;
+        @x [Symbol.toStringTag]: any;
+        @x ["property2"]: any = 2;
+        @x [Symbol.iterator]: any = null;
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any = null;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        ["some" + "method"]() {}
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        ["some" + "method2"]() {}
+        @x [fieldNameC]: any = null;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+    }
+    
+    void class H {
+        @x ["property"]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.toStringTag]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["property2"]: any = 2;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.iterator]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [foo()]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["some" + "method"]() {}
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["some" + "method2"]() {}
+        @x [fieldNameC]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+    };
+    
+    class I {
+        @x ["property"]: any;
+        @x [Symbol.toStringTag]: any;
+        @x ["property2"]: any = 2;
+        @x [Symbol.iterator]: any = null;
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any = null;
+           ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x ["some" + "method"]() {}
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        ["some" + "method2"]() {}
+        @x [fieldNameC]: any = null;
+           ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+    }
+    
+    void class J {
+        @x ["property"]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.toStringTag]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["property2"]: any = 2;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [Symbol.iterator]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["property3"]: any;
+        [Symbol.isConcatSpreadable]: any;
+        ["property4"]: any = 2;
+        [Symbol.match]: any = null;
+        [foo()]: any;
+        ~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [foo()]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x [foo()]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        @x ["some" + "method"]() {}
+        ~
+!!! error TS1206: Decorators are not valid here.
+        [fieldNameA]: any;
+        ~~~~~~~~~~~~
+!!! error TS1166: A computed property name in a class property declaration must directly refer to a built-in symbol.
+        @x [fieldNameB]: any;
+        ~
+!!! error TS1206: Decorators are not valid here.
+        ["some" + "method2"]() {}
+        @x [fieldNameC]: any = null;
+        ~
+!!! error TS1206: Decorators are not valid here.
+    };
\ No newline at end of file
diff --git a/tests/baselines/reference/decoratorsOnComputedProperties.js b/tests/baselines/reference/decoratorsOnComputedProperties.js
new file mode 100644
index 00000000000..0083bc8b9a1
--- /dev/null
+++ b/tests/baselines/reference/decoratorsOnComputedProperties.js
@@ -0,0 +1,457 @@
+//// [decoratorsOnComputedProperties.ts]
+function x(o: object, k: PropertyKey) { }
+let i = 0;
+function foo(): string { return ++i + ""; }
+
+const fieldNameA: string = "fieldName1";
+const fieldNameB: string = "fieldName2";
+const fieldNameC: string = "fieldName3";
+
+class A {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+}
+
+void class B {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+};
+
+class C {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+    ["some" + "method"]() {}
+}
+
+void class D {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+    ["some" + "method"]() {}
+};
+
+class E {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+}
+
+void class F {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+};
+
+class G {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+}
+
+void class H {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+};
+
+class I {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    @x ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+}
+
+void class J {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    @x ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+};
+
+//// [decoratorsOnComputedProperties.js]
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+function x(o, k) { }
+let i = 0;
+function foo() { return ++i + ""; }
+const fieldNameA = "fieldName1";
+const fieldNameB = "fieldName2";
+const fieldNameC = "fieldName3";
+class A {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_a] = null;
+        this[_b] = null;
+    }
+}
+foo(), _c = foo(), _a = foo(), _d = fieldNameB, _b = fieldNameC;
+__decorate([
+    x
+], A.prototype, "property", void 0);
+__decorate([
+    x
+], A.prototype, Symbol.toStringTag, void 0);
+__decorate([
+    x
+], A.prototype, "property2", void 0);
+__decorate([
+    x
+], A.prototype, Symbol.iterator, void 0);
+__decorate([
+    x
+], A.prototype, _c, void 0);
+__decorate([
+    x
+], A.prototype, _a, void 0);
+__decorate([
+    x
+], A.prototype, _d, void 0);
+__decorate([
+    x
+], A.prototype, _b, void 0);
+void (_e = class B {
+        constructor() {
+            this["property2"] = 2;
+            this[Symbol.iterator] = null;
+            this["property4"] = 2;
+            this[Symbol.match] = null;
+            this[_f] = null;
+            this[_g] = null;
+        }
+    },
+    foo(),
+    _h = foo(),
+    _f = foo(),
+    _j = fieldNameB,
+    _g = fieldNameC,
+    _e);
+class C {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_k] = null;
+        this[_l] = null;
+    }
+    [foo(), _m = foo(), _k = foo(), _o = fieldNameB, _l = fieldNameC, "some" + "method"]() { }
+}
+__decorate([
+    x
+], C.prototype, "property", void 0);
+__decorate([
+    x
+], C.prototype, Symbol.toStringTag, void 0);
+__decorate([
+    x
+], C.prototype, "property2", void 0);
+__decorate([
+    x
+], C.prototype, Symbol.iterator, void 0);
+__decorate([
+    x
+], C.prototype, _m, void 0);
+__decorate([
+    x
+], C.prototype, _k, void 0);
+__decorate([
+    x
+], C.prototype, _o, void 0);
+__decorate([
+    x
+], C.prototype, _l, void 0);
+void class D {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_p] = null;
+        this[_q] = null;
+    }
+    [foo(), _r = foo(), _p = foo(), _s = fieldNameB, _q = fieldNameC, "some" + "method"]() { }
+};
+class E {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_t] = null;
+        this[_u] = null;
+    }
+    [foo(), _v = foo(), _t = foo(), "some" + "method"]() { }
+}
+_w = fieldNameB, _u = fieldNameC;
+__decorate([
+    x
+], E.prototype, "property", void 0);
+__decorate([
+    x
+], E.prototype, Symbol.toStringTag, void 0);
+__decorate([
+    x
+], E.prototype, "property2", void 0);
+__decorate([
+    x
+], E.prototype, Symbol.iterator, void 0);
+__decorate([
+    x
+], E.prototype, _v, void 0);
+__decorate([
+    x
+], E.prototype, _t, void 0);
+__decorate([
+    x
+], E.prototype, _w, void 0);
+__decorate([
+    x
+], E.prototype, _u, void 0);
+void (_x = class F {
+        constructor() {
+            this["property2"] = 2;
+            this[Symbol.iterator] = null;
+            this["property4"] = 2;
+            this[Symbol.match] = null;
+            this[_y] = null;
+            this[_z] = null;
+        }
+        [foo(), _0 = foo(), _y = foo(), "some" + "method"]() { }
+    },
+    _1 = fieldNameB,
+    _z = fieldNameC,
+    _x);
+class G {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_2] = null;
+        this[_3] = null;
+    }
+    [foo(), _4 = foo(), _2 = foo(), "some" + "method"]() { }
+    [_5 = fieldNameB, "some" + "method2"]() { }
+}
+_3 = fieldNameC;
+__decorate([
+    x
+], G.prototype, "property", void 0);
+__decorate([
+    x
+], G.prototype, Symbol.toStringTag, void 0);
+__decorate([
+    x
+], G.prototype, "property2", void 0);
+__decorate([
+    x
+], G.prototype, Symbol.iterator, void 0);
+__decorate([
+    x
+], G.prototype, _4, void 0);
+__decorate([
+    x
+], G.prototype, _2, void 0);
+__decorate([
+    x
+], G.prototype, _5, void 0);
+__decorate([
+    x
+], G.prototype, _3, void 0);
+void (_6 = class H {
+        constructor() {
+            this["property2"] = 2;
+            this[Symbol.iterator] = null;
+            this["property4"] = 2;
+            this[Symbol.match] = null;
+            this[_7] = null;
+            this[_8] = null;
+        }
+        [foo(), _9 = foo(), _7 = foo(), "some" + "method"]() { }
+        [_10 = fieldNameB, "some" + "method2"]() { }
+    },
+    _8 = fieldNameC,
+    _6);
+class I {
+    constructor() {
+        this["property2"] = 2;
+        this[Symbol.iterator] = null;
+        this["property4"] = 2;
+        this[Symbol.match] = null;
+        this[_11] = null;
+        this[_12] = null;
+    }
+    [foo(), _13 = foo(), _11 = foo(), _14 = "some" + "method"]() { }
+    [_15 = fieldNameB, "some" + "method2"]() { }
+}
+_12 = fieldNameC;
+__decorate([
+    x
+], I.prototype, "property", void 0);
+__decorate([
+    x
+], I.prototype, Symbol.toStringTag, void 0);
+__decorate([
+    x
+], I.prototype, "property2", void 0);
+__decorate([
+    x
+], I.prototype, Symbol.iterator, void 0);
+__decorate([
+    x
+], I.prototype, _13, void 0);
+__decorate([
+    x
+], I.prototype, _11, void 0);
+__decorate([
+    x
+], I.prototype, _14, null);
+__decorate([
+    x
+], I.prototype, _15, void 0);
+__decorate([
+    x
+], I.prototype, _12, void 0);
+void (_16 = class J {
+        constructor() {
+            this["property2"] = 2;
+            this[Symbol.iterator] = null;
+            this["property4"] = 2;
+            this[Symbol.match] = null;
+            this[_17] = null;
+            this[_18] = null;
+        }
+        [foo(), _19 = foo(), _17 = foo(), _20 = "some" + "method"]() { }
+        [_21 = fieldNameB, "some" + "method2"]() { }
+    },
+    _18 = fieldNameC,
+    _16);
+var _c, _a, _d, _b, _h, _f, _j, _g, _e, _m, _k, _o, _l, _r, _p, _s, _q, _v, _t, _w, _u, _0, _y, _1, _z, _x, _4, _2, _5, _3, _9, _7, _10, _8, _6, _13, _11, _14, _15, _12, _19, _17, _20, _21, _18, _16;
diff --git a/tests/baselines/reference/decoratorsOnComputedProperties.symbols b/tests/baselines/reference/decoratorsOnComputedProperties.symbols
new file mode 100644
index 00000000000..a9fb280f96e
--- /dev/null
+++ b/tests/baselines/reference/decoratorsOnComputedProperties.symbols
@@ -0,0 +1,664 @@
+=== tests/cases/compiler/decoratorsOnComputedProperties.ts ===
+function x(o: object, k: PropertyKey) { }
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>o : Symbol(o, Decl(decoratorsOnComputedProperties.ts, 0, 11))
+>k : Symbol(k, Decl(decoratorsOnComputedProperties.ts, 0, 21))
+>PropertyKey : Symbol(PropertyKey, Decl(lib.es2015.core.d.ts, --, --))
+
+let i = 0;
+>i : Symbol(i, Decl(decoratorsOnComputedProperties.ts, 1, 3))
+
+function foo(): string { return ++i + ""; }
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+>i : Symbol(i, Decl(decoratorsOnComputedProperties.ts, 1, 3))
+
+const fieldNameA: string = "fieldName1";
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+const fieldNameB: string = "fieldName2";
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+const fieldNameC: string = "fieldName3";
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+class A {
+>A : Symbol(A, Decl(decoratorsOnComputedProperties.ts, 6, 40))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(A[["property"]], Decl(decoratorsOnComputedProperties.ts, 8, 9))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(A[["property2"]], Decl(decoratorsOnComputedProperties.ts, 10, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(A[["property3"]], Decl(decoratorsOnComputedProperties.ts, 12, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(A[["property4"]], Decl(decoratorsOnComputedProperties.ts, 14, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+}
+
+void class B {
+>B : Symbol(B, Decl(decoratorsOnComputedProperties.ts, 25, 4))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(B[["property"]], Decl(decoratorsOnComputedProperties.ts, 25, 14))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(B[["property2"]], Decl(decoratorsOnComputedProperties.ts, 27, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(B[["property3"]], Decl(decoratorsOnComputedProperties.ts, 29, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(B[["property4"]], Decl(decoratorsOnComputedProperties.ts, 31, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+};
+
+class C {
+>C : Symbol(C, Decl(decoratorsOnComputedProperties.ts, 40, 2))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(C[["property"]], Decl(decoratorsOnComputedProperties.ts, 42, 9))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(C[["property2"]], Decl(decoratorsOnComputedProperties.ts, 44, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(C[["property3"]], Decl(decoratorsOnComputedProperties.ts, 46, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(C[["property4"]], Decl(decoratorsOnComputedProperties.ts, 48, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+    ["some" + "method"]() {}
+}
+
+void class D {
+>D : Symbol(D, Decl(decoratorsOnComputedProperties.ts, 60, 4))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(D[["property"]], Decl(decoratorsOnComputedProperties.ts, 60, 14))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(D[["property2"]], Decl(decoratorsOnComputedProperties.ts, 62, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(D[["property3"]], Decl(decoratorsOnComputedProperties.ts, 64, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(D[["property4"]], Decl(decoratorsOnComputedProperties.ts, 66, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+    ["some" + "method"]() {}
+};
+
+class E {
+>E : Symbol(E, Decl(decoratorsOnComputedProperties.ts, 76, 2))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(E[["property"]], Decl(decoratorsOnComputedProperties.ts, 78, 9))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(E[["property2"]], Decl(decoratorsOnComputedProperties.ts, 80, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(E[["property3"]], Decl(decoratorsOnComputedProperties.ts, 82, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(E[["property4"]], Decl(decoratorsOnComputedProperties.ts, 84, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+}
+
+void class F {
+>F : Symbol(F, Decl(decoratorsOnComputedProperties.ts, 96, 4))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(F[["property"]], Decl(decoratorsOnComputedProperties.ts, 96, 14))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(F[["property2"]], Decl(decoratorsOnComputedProperties.ts, 98, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(F[["property3"]], Decl(decoratorsOnComputedProperties.ts, 100, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(F[["property4"]], Decl(decoratorsOnComputedProperties.ts, 102, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+};
+
+class G {
+>G : Symbol(G, Decl(decoratorsOnComputedProperties.ts, 112, 2))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(G[["property"]], Decl(decoratorsOnComputedProperties.ts, 114, 9))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(G[["property2"]], Decl(decoratorsOnComputedProperties.ts, 116, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(G[["property3"]], Decl(decoratorsOnComputedProperties.ts, 118, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(G[["property4"]], Decl(decoratorsOnComputedProperties.ts, 120, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+}
+
+void class H {
+>H : Symbol(H, Decl(decoratorsOnComputedProperties.ts, 133, 4))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(H[["property"]], Decl(decoratorsOnComputedProperties.ts, 133, 14))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(H[["property2"]], Decl(decoratorsOnComputedProperties.ts, 135, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(H[["property3"]], Decl(decoratorsOnComputedProperties.ts, 137, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(H[["property4"]], Decl(decoratorsOnComputedProperties.ts, 139, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+};
+
+class I {
+>I : Symbol(I, Decl(decoratorsOnComputedProperties.ts, 150, 2))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(I[["property"]], Decl(decoratorsOnComputedProperties.ts, 152, 9))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(I[["property2"]], Decl(decoratorsOnComputedProperties.ts, 154, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(I[["property3"]], Decl(decoratorsOnComputedProperties.ts, 156, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(I[["property4"]], Decl(decoratorsOnComputedProperties.ts, 158, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x ["some" + "method"]() {}
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+}
+
+void class J {
+>J : Symbol(J, Decl(decoratorsOnComputedProperties.ts, 171, 4))
+
+    @x ["property"]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property" : Symbol(J[["property"]], Decl(decoratorsOnComputedProperties.ts, 171, 14))
+
+    @x [Symbol.toStringTag]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>toStringTag : Symbol(SymbolConstructor.toStringTag, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    @x ["property2"]: any = 2;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>"property2" : Symbol(J[["property2"]], Decl(decoratorsOnComputedProperties.ts, 173, 33))
+
+    @x [Symbol.iterator]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>Symbol.iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>iterator : Symbol(SymbolConstructor.iterator, Decl(lib.es2015.iterable.d.ts, --, --))
+
+    ["property3"]: any;
+>"property3" : Symbol(J[["property3"]], Decl(decoratorsOnComputedProperties.ts, 175, 37))
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>isConcatSpreadable : Symbol(SymbolConstructor.isConcatSpreadable, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    ["property4"]: any = 2;
+>"property4" : Symbol(J[["property4"]], Decl(decoratorsOnComputedProperties.ts, 177, 37))
+
+    [Symbol.match]: any = null;
+>Symbol.match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>match : Symbol(SymbolConstructor.match, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+
+    [foo()]: any;
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x [foo()]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>foo : Symbol(foo, Decl(decoratorsOnComputedProperties.ts, 1, 10))
+
+    @x ["some" + "method"]() {}
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+
+    [fieldNameA]: any;
+>fieldNameA : Symbol(fieldNameA, Decl(decoratorsOnComputedProperties.ts, 4, 5))
+
+    @x [fieldNameB]: any;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameB : Symbol(fieldNameB, Decl(decoratorsOnComputedProperties.ts, 5, 5))
+
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+>x : Symbol(x, Decl(decoratorsOnComputedProperties.ts, 0, 0))
+>fieldNameC : Symbol(fieldNameC, Decl(decoratorsOnComputedProperties.ts, 6, 5))
+
+};
diff --git a/tests/baselines/reference/decoratorsOnComputedProperties.types b/tests/baselines/reference/decoratorsOnComputedProperties.types
new file mode 100644
index 00000000000..4976812b8d4
--- /dev/null
+++ b/tests/baselines/reference/decoratorsOnComputedProperties.types
@@ -0,0 +1,816 @@
+=== tests/cases/compiler/decoratorsOnComputedProperties.ts ===
+function x(o: object, k: PropertyKey) { }
+>x : (o: object, k: PropertyKey) => void
+>o : object
+>k : PropertyKey
+>PropertyKey : PropertyKey
+
+let i = 0;
+>i : number
+>0 : 0
+
+function foo(): string { return ++i + ""; }
+>foo : () => string
+>++i + "" : string
+>++i : number
+>i : number
+>"" : ""
+
+const fieldNameA: string = "fieldName1";
+>fieldNameA : string
+>"fieldName1" : "fieldName1"
+
+const fieldNameB: string = "fieldName2";
+>fieldNameB : string
+>"fieldName2" : "fieldName2"
+
+const fieldNameC: string = "fieldName3";
+>fieldNameC : string
+>"fieldName3" : "fieldName3"
+
+class A {
+>A : A
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+}
+
+void class B {
+>void class B {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;} : undefined
+>class B {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;} : typeof B
+>B : typeof B
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+};
+
+class C {
+>C : C
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+}
+
+void class D {
+>void class D {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;    ["some" + "method"]() {}} : undefined
+>class D {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;    ["some" + "method"]() {}} : typeof D
+>D : typeof D
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+};
+
+class E {
+>E : E
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+}
+
+void class F {
+>void class F {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;} : undefined
+>class F {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    @x [fieldNameC]: any = null;} : typeof F
+>F : typeof F
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+};
+
+class G {
+>G : G
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    ["some" + "method2"]() {}
+>"some" + "method2" : string
+>"some" : "some"
+>"method2" : "method2"
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+}
+
+void class H {
+>void class H {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    ["some" + "method2"]() {}    @x [fieldNameC]: any = null;} : undefined
+>class H {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    ["some" + "method2"]() {}    @x [fieldNameC]: any = null;} : typeof H
+>H : typeof H
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    ["some" + "method"]() {}
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    ["some" + "method2"]() {}
+>"some" + "method2" : string
+>"some" : "some"
+>"method2" : "method2"
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+};
+
+class I {
+>I : I
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    @x ["some" + "method"]() {}
+>x : (o: object, k: PropertyKey) => void
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    ["some" + "method2"]() {}
+>"some" + "method2" : string
+>"some" : "some"
+>"method2" : "method2"
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+}
+
+void class J {
+>void class J {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    @x ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    ["some" + "method2"]() {}    @x [fieldNameC]: any = null;} : undefined
+>class J {    @x ["property"]: any;    @x [Symbol.toStringTag]: any;    @x ["property2"]: any = 2;    @x [Symbol.iterator]: any = null;    ["property3"]: any;    [Symbol.isConcatSpreadable]: any;    ["property4"]: any = 2;    [Symbol.match]: any = null;    [foo()]: any;    @x [foo()]: any;    @x [foo()]: any = null;    @x ["some" + "method"]() {}    [fieldNameA]: any;    @x [fieldNameB]: any;    ["some" + "method2"]() {}    @x [fieldNameC]: any = null;} : typeof J
+>J : typeof J
+
+    @x ["property"]: any;
+>x : (o: object, k: PropertyKey) => void
+>"property" : "property"
+
+    @x [Symbol.toStringTag]: any;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.toStringTag : symbol
+>Symbol : SymbolConstructor
+>toStringTag : symbol
+
+    @x ["property2"]: any = 2;
+>x : (o: object, k: PropertyKey) => void
+>"property2" : "property2"
+>2 : 2
+
+    @x [Symbol.iterator]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>Symbol.iterator : symbol
+>Symbol : SymbolConstructor
+>iterator : symbol
+>null : null
+
+    ["property3"]: any;
+>"property3" : "property3"
+
+    [Symbol.isConcatSpreadable]: any;
+>Symbol.isConcatSpreadable : symbol
+>Symbol : SymbolConstructor
+>isConcatSpreadable : symbol
+
+    ["property4"]: any = 2;
+>"property4" : "property4"
+>2 : 2
+
+    [Symbol.match]: any = null;
+>Symbol.match : symbol
+>Symbol : SymbolConstructor
+>match : symbol
+>null : null
+
+    [foo()]: any;
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+
+    @x [foo()]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>foo() : string
+>foo : () => string
+>null : null
+
+    @x ["some" + "method"]() {}
+>x : (o: object, k: PropertyKey) => void
+>"some" + "method" : string
+>"some" : "some"
+>"method" : "method"
+
+    [fieldNameA]: any;
+>fieldNameA : string
+
+    @x [fieldNameB]: any;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameB : string
+
+    ["some" + "method2"]() {}
+>"some" + "method2" : string
+>"some" : "some"
+>"method2" : "method2"
+
+    @x [fieldNameC]: any = null;
+>x : (o: object, k: PropertyKey) => void
+>fieldNameC : string
+>null : null
+
+};
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES5.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration1ES5.errors.txt
index 8e51c2b6111..fbbfc3b0d21 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES5.errors.txt
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES5.errors.txt
@@ -1,8 +1,14 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts(12,4): error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts(57,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts(62,10): error TS2393: Duplicate function implementation.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts(63,10): error TS2393: Duplicate function implementation.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts (2 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.ts (4 errors) ====
     // A parameter declaration may specify either an identifier or a binding pattern.
     // The identifiers specified in parameter declarations and binding patterns
     // in a parameter list must be unique within that parameter list.
@@ -15,6 +21,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.
     
     a1([1, 2, [["world"]]]);
     a1([1, 2, [["world"]], 3]);
+       ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '4' is not assignable to type '3'.
     
     // If the declaration includes an initializer expression (which is permitted only
     // when the parameter list occurs in conjunction with a function body),
@@ -60,6 +70,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5.
     
     c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]]
     c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
     
     // A parameter can be marked optional by following its name or binding pattern with a question mark (?)
     // or by including an initializer.
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES5.types b/tests/baselines/reference/destructuringParameterDeclaration1ES5.types
index a4b7e882298..c7a5c44f1d4 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES5.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES5.types
@@ -54,7 +54,7 @@ a1([1, 2, [["world"]]]);
 a1([1, 2, [["world"]], 3]);
 >a1([1, 2, [["world"]], 3]) : void
 >a1 : ([a, b, [[c]]]: [number, number, string[][]]) => void
->[1, 2, [["world"]], 3] : [number, number, string[][], number]
+>[1, 2, [["world"]], 3] : (number | string[][])[]
 >1 : 1
 >2 : 2
 >[["world"]] : string[][]
@@ -304,11 +304,11 @@ c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]
 c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
 >c5([1, 2, [["string"]], false, true]) : void
 >c5 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.errors.txt
index 101a37fc84a..1dc3c61bb3a 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.errors.txt
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.errors.txt
@@ -1,8 +1,14 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts(12,4): error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts(57,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts(62,10): error TS2393: Duplicate function implementation.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts(63,10): error TS2393: Duplicate function implementation.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts (2 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5iterable.ts (4 errors) ====
     // A parameter declaration may specify either an identifier or a binding pattern.
     // The identifiers specified in parameter declarations and binding patterns
     // in a parameter list must be unique within that parameter list.
@@ -15,6 +21,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5i
     
     a1([1, 2, [["world"]]]);
     a1([1, 2, [["world"]], 3]);
+       ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '4' is not assignable to type '3'.
     
     // If the declaration includes an initializer expression (which is permitted only
     // when the parameter list occurs in conjunction with a function body),
@@ -60,6 +70,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES5i
     
     c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]]
     c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
     
     // A parameter can be marked optional by following its name or binding pattern with a question mark (?)
     // or by including an initializer.
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.types b/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.types
index 9d72faf55b6..b41a2027586 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.types
@@ -54,7 +54,7 @@ a1([1, 2, [["world"]]]);
 a1([1, 2, [["world"]], 3]);
 >a1([1, 2, [["world"]], 3]) : void
 >a1 : ([a, b, [[c]]]: [number, number, string[][]]) => void
->[1, 2, [["world"]], 3] : [number, number, string[][], number]
+>[1, 2, [["world"]], 3] : (number | string[][])[]
 >1 : 1
 >2 : 2
 >[["world"]] : string[][]
@@ -304,11 +304,11 @@ c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]
 c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
 >c5([1, 2, [["string"]], false, true]) : void
 >c5 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES6.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration1ES6.errors.txt
index e900b9be393..f6c17a5c0ea 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES6.errors.txt
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES6.errors.txt
@@ -1,9 +1,15 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts(14,4): error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts(58,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts(96,18): error TS2300: Duplicate identifier 'number'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts(96,26): error TS2300: Duplicate identifier 'number'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts(96,34): error TS2300: Duplicate identifier 'number'.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts (3 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.ts (5 errors) ====
     // Conformance for emitting ES6
     
     // A parameter declaration may specify either an identifier or a binding pattern.
@@ -18,6 +24,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.
     
     a1([1, 2, [["world"]]]);
     a1([1, 2, [["world"]], 3]);
+       ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, string[][], number]' is not assignable to parameter of type '[number, number, string[][]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '4' is not assignable to type '3'.
     
     
     // If the declaration includes an initializer expression (which is permitted only
@@ -62,6 +72,10 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration1ES6.
     
     c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]]
     c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
     
     
     // A parameter can be marked optional by following its name or binding pattern with a question mark (?)
diff --git a/tests/baselines/reference/destructuringParameterDeclaration1ES6.types b/tests/baselines/reference/destructuringParameterDeclaration1ES6.types
index b997dcf6017..9de904efdec 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration1ES6.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration1ES6.types
@@ -56,7 +56,7 @@ a1([1, 2, [["world"]]]);
 a1([1, 2, [["world"]], 3]);
 >a1([1, 2, [["world"]], 3]) : void
 >a1 : ([a, b, [[c]]]: [number, number, string[][]]) => void
->[1, 2, [["world"]], 3] : [number, number, string[][], number]
+>[1, 2, [["world"]], 3] : (number | string[][])[]
 >1 : 1
 >2 : 2
 >[["world"]] : string[][]
@@ -287,11 +287,11 @@ c5([1, 2, [["string"]]]);               // Implied type is is [any, any, [[any]]
 c5([1, 2, [["string"]], false, true]);  // Implied type is is [any, any, [[any]]]
 >c5([1, 2, [["string"]], false, true]) : void
 >c5 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/destructuringParameterDeclaration2.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration2.errors.txt
index 81c85f7c42b..96b93423660 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration2.errors.txt
+++ b/tests/baselines/reference/destructuringParameterDeclaration2.errors.txt
@@ -2,10 +2,8 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
   Type 'string' is not assignable to type 'number'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(7,29): error TS1005: ',' expected.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(8,4): error TS2345: Argument of type '[number, number, string[][], string]' is not assignable to parameter of type '[number, number, string[][]]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number | string[][]' is not assignable to type '() => number | string[][]'.
-      Type 'string | number | string[][]' is not assignable to type 'number | string[][]'.
-        Type 'string' is not assignable to type 'number | string[][]'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '3'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(16,8): error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(16,16): error TS2371: A parameter initializer is only allowed in a function or constructor implementation.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(23,14): error TS2345: Argument of type '{ x: string; y: boolean; }' is not assignable to parameter of type '{ x: number; y: any; }'.
@@ -64,10 +62,8 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
     a0([1, 2, [["world"]], "string"]);  // Error
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '[number, number, string[][], string]' is not assignable to parameter of type '[number, number, string[][]]'.
-!!! error TS2345:   Types of property 'pop' are incompatible.
-!!! error TS2345:     Type '() => string | number | string[][]' is not assignable to type '() => number | string[][]'.
-!!! error TS2345:       Type 'string | number | string[][]' is not assignable to type 'number | string[][]'.
-!!! error TS2345:         Type 'string' is not assignable to type 'number | string[][]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '4' is not assignable to type '3'.
     
     
     // If the declaration includes an initializer expression (which is permitted only
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES5.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration3ES5.errors.txt
new file mode 100644
index 00000000000..3b16993a047
--- /dev/null
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES5.errors.txt
@@ -0,0 +1,55 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts (1 errors) ====
+    // If the parameter is a rest parameter, the parameter type is any[]
+    // A type annotation for a rest parameter must denote an array type.
+    
+    // RestParameter:
+    //     ...   Identifier   TypeAnnotation(opt)
+    
+    type arrayString = Array<String>
+    type someArray = Array<String> | number[];
+    type stringOrNumArray = Array<String|Number>;
+    
+    function a1(...x: (number|string)[]) { }
+    function a2(...a) { }
+    function a3(...a: Array<String>) { }
+    function a4(...a: arrayString) { }
+    function a5(...a: stringOrNumArray) { }
+    function a9([a, b, [[c]]]) { }
+    function a10([a, b, [[c]], ...x]) { }
+    function a11([a, b, c, ...x]: number[]) { }
+    
+    
+    var array = [1, 2, 3];
+    var array2 = [true, false, "hello"];
+    a2([...array]);
+    a1(...array);
+    
+    a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
+    
+    a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
+    a10([1, 2, 3, false, true]);              // Parameter type is any[]
+    a10([1, 2]);                              // Parameter type is any[]
+    a11([1, 2]);                              // Parameter type is number[]
+    
+    // Rest parameter with generic
+    function foo<T>(...a: T[]) { }
+    foo<number|string>("hello", 1, 2);
+    foo("hello", "world");
+    
+    enum E { a, b }
+    const enum E1 { a, b }
+    function foo1<T extends Number>(...a: T[]) { }
+    foo1(1, 2, 3, E.a);
+    foo1(1, 2, 3, E1.a, E.b);
+    
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES5.types b/tests/baselines/reference/destructuringParameterDeclaration3ES5.types
index a91d54d5284..33e0d3b6bd8 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration3ES5.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES5.types
@@ -96,11 +96,11 @@ a1(...array);
 a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
 >a9([1, 2, [["string"]], false, true]) : void
 >a9 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.errors.txt
new file mode 100644
index 00000000000..f0dbf325ed4
--- /dev/null
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.errors.txt
@@ -0,0 +1,55 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts (1 errors) ====
+    // If the parameter is a rest parameter, the parameter type is any[]
+    // A type annotation for a rest parameter must denote an array type.
+    
+    // RestParameter:
+    //     ...   Identifier   TypeAnnotation(opt)
+    
+    type arrayString = Array<String>
+    type someArray = Array<String> | number[];
+    type stringOrNumArray = Array<String|Number>;
+    
+    function a1(...x: (number|string)[]) { }
+    function a2(...a) { }
+    function a3(...a: Array<String>) { }
+    function a4(...a: arrayString) { }
+    function a5(...a: stringOrNumArray) { }
+    function a9([a, b, [[c]]]) { }
+    function a10([a, b, [[c]], ...x]) { }
+    function a11([a, b, c, ...x]: number[]) { }
+    
+    
+    var array = [1, 2, 3];
+    var array2 = [true, false, "hello"];
+    a2([...array]);
+    a1(...array);
+    
+    a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
+    
+    a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
+    a10([1, 2, 3, false, true]);              // Parameter type is any[]
+    a10([1, 2]);                              // Parameter type is any[]
+    a11([1, 2]);                              // Parameter type is number[]
+    
+    // Rest parameter with generic
+    function foo<T>(...a: T[]) { }
+    foo<number|string>("hello", 1, 2);
+    foo("hello", "world");
+    
+    enum E { a, b }
+    const enum E1 { a, b }
+    function foo1<T extends Number>(...a: T[]) { }
+    foo1(1, 2, 3, E.a);
+    foo1(1, 2, 3, E1.a, E.b);
+    
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.types b/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.types
index 5f2963abe87..931e149ffe2 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.types
@@ -96,11 +96,11 @@ a1(...array);
 a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
 >a9([1, 2, [["string"]], false, true]) : void
 >a9 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES6.errors.txt b/tests/baselines/reference/destructuringParameterDeclaration3ES6.errors.txt
new file mode 100644
index 00000000000..67a5c1bf87f
--- /dev/null
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES6.errors.txt
@@ -0,0 +1,55 @@
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+  Types of property 'length' are incompatible.
+    Type '5' is not assignable to type '3'.
+
+
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts (1 errors) ====
+    // If the parameter is a rest parameter, the parameter type is any[]
+    // A type annotation for a rest parameter must denote an array type.
+    
+    // RestParameter:
+    //     ...   Identifier   TypeAnnotation(opt)
+    
+    type arrayString = Array<String>
+    type someArray = Array<String> | number[];
+    type stringOrNumArray = Array<String|Number>;
+    
+    function a1(...x: (number|string)[]) { }
+    function a2(...a) { }
+    function a3(...a: Array<String>) { }
+    function a4(...a: arrayString) { }
+    function a5(...a: stringOrNumArray) { }
+    function a9([a, b, [[c]]]) { }
+    function a10([a, b, [[c]], ...x]) { }
+    function a11([a, b, c, ...x]: number[]) { }
+    
+    
+    var array = [1, 2, 3];
+    var array2 = [true, false, "hello"];
+    a2([...array]);
+    a1(...array);
+    
+    a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
+       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type '5' is not assignable to type '3'.
+    
+    a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
+    a10([1, 2, 3, false, true]);              // Parameter type is any[]
+    a10([1, 2]);                              // Parameter type is any[]
+    a11([1, 2]);                              // Parameter type is number[]
+    
+    // Rest parameter with generic
+    function foo<T>(...a: T[]) { }
+    foo<number|string>("hello", 1, 2);
+    foo("hello", "world");
+    
+    enum E { a, b }
+    const enum E1 { a, b }
+    function foo1<T extends Number>(...a: T[]) { }
+    foo1(1, 2, 3, E.a);
+    foo1(1, 2, 3, E1.a, E.b);
+    
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/destructuringParameterDeclaration3ES6.types b/tests/baselines/reference/destructuringParameterDeclaration3ES6.types
index 397ec934a2f..dc5e64d2c2c 100644
--- a/tests/baselines/reference/destructuringParameterDeclaration3ES6.types
+++ b/tests/baselines/reference/destructuringParameterDeclaration3ES6.types
@@ -96,11 +96,11 @@ a1(...array);
 a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]]
 >a9([1, 2, [["string"]], false, true]) : void
 >a9 : ([a, b, [[c]]]: [any, any, [[any]]]) => void
->[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
+>[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
 >1 : 1
 >2 : 2
->[["string"]] : [[string]]
->["string"] : [string]
+>[["string"]] : string[][]
+>["string"] : string[]
 >"string" : "string"
 >false : false
 >true : true
diff --git a/tests/baselines/reference/errorSupression1.js b/tests/baselines/reference/errorSupression1.js
index 2f467871434..4b635a0d660 100644
--- a/tests/baselines/reference/errorSupression1.js
+++ b/tests/baselines/reference/errorSupression1.js
@@ -17,4 +17,4 @@ var Foo = /** @class */ (function () {
 var baz = Foo.b;
 // Foo.b won't bind. 
 baz.concat("y");
-// So we don't want an error on 'concat'. 
+// So we don't want an error on 'concat'.
diff --git a/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifier.types b/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifier.types
index abb1c3b69e2..acbe40fb9ab 100644
--- a/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifier.types
+++ b/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifier.types
@@ -30,8 +30,8 @@ export { c as c2 } from "server";
 
 export { i, m as instantiatedModule } from "server";
 >i : any
->m : typeof m
->instantiatedModule : typeof m
+>m : typeof instantiatedModule
+>instantiatedModule : typeof instantiatedModule
 
 export { uninstantiated } from "server";
 >uninstantiated : any
diff --git a/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifierInEs5.types b/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifierInEs5.types
index b407d9b16f5..8a7e9c29b10 100644
--- a/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifierInEs5.types
+++ b/tests/baselines/reference/es6ExportClauseWithoutModuleSpecifierInEs5.types
@@ -30,8 +30,8 @@ export { c as c2 } from "./server";
 
 export { i, m as instantiatedModule } from "./server";
 >i : any
->m : typeof m
->instantiatedModule : typeof m
+>m : typeof instantiatedModule
+>instantiatedModule : typeof instantiatedModule
 
 export { uninstantiated } from "./server";
 >uninstantiated : any
diff --git a/tests/baselines/reference/everyTypeAssignableToAny.js b/tests/baselines/reference/everyTypeAssignableToAny.js
index 7f02badca00..fd71ec624be 100644
--- a/tests/baselines/reference/everyTypeAssignableToAny.js
+++ b/tests/baselines/reference/everyTypeAssignableToAny.js
@@ -117,4 +117,4 @@ function foo(x, y, z) {
 //    a = x;
 //    a = y;
 //    a = z;
-//} 
+//}
diff --git a/tests/baselines/reference/excessPropertyCheckWithUnions.errors.txt b/tests/baselines/reference/excessPropertyCheckWithUnions.errors.txt
index 9fbbb001605..d802733354e 100644
--- a/tests/baselines/reference/excessPropertyCheckWithUnions.errors.txt
+++ b/tests/baselines/reference/excessPropertyCheckWithUnions.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/compiler/excessPropertyCheckWithUnions.ts(10,30): error TS2322: Type '{ tag: "T"; a1: string; }' is not assignable to type 'ADT'.
   Object literal may only specify known properties, and 'a1' does not exist in type '{ tag: "T"; }'.
-tests/cases/compiler/excessPropertyCheckWithUnions.ts(11,21): error TS2322: Type '{ tag: "A"; d20: 12; }' is not assignable to type 'ADT'.
+tests/cases/compiler/excessPropertyCheckWithUnions.ts(11,21): error TS2322: Type '{ tag: "A"; d20: number; }' is not assignable to type 'ADT'.
   Object literal may only specify known properties, and 'd20' does not exist in type '{ tag: "A"; a1: string; }'.
 tests/cases/compiler/excessPropertyCheckWithUnions.ts(12,1): error TS2322: Type '{ tag: "D"; }' is not assignable to type 'ADT'.
   Type '{ tag: "D"; }' is not assignable to type '{ tag: "D"; d20: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20; }'.
@@ -17,9 +17,13 @@ tests/cases/compiler/excessPropertyCheckWithUnions.ts(40,1): error TS2322: Type
   Type '{ tag: "A"; z: true; }' is not assignable to type '{ tag: "C"; }'.
     Types of property 'tag' are incompatible.
       Type '"A"' is not assignable to type '"C"'.
+tests/cases/compiler/excessPropertyCheckWithUnions.ts(49,35): error TS2322: Type '{ a: 1; b: 1; first: string; second: string; }' is not assignable to type 'Overlapping'.
+  Object literal may only specify known properties, and 'second' does not exist in type '{ a: 1; b: 1; first: string; }'.
+tests/cases/compiler/excessPropertyCheckWithUnions.ts(50,35): error TS2322: Type '{ a: 1; b: 1; first: string; third: string; }' is not assignable to type 'Overlapping'.
+  Object literal may only specify known properties, and 'third' does not exist in type '{ a: 1; b: 1; first: string; }'.
 
 
-==== tests/cases/compiler/excessPropertyCheckWithUnions.ts (7 errors) ====
+==== tests/cases/compiler/excessPropertyCheckWithUnions.ts (9 errors) ====
     type ADT = {
         tag: "A",
         a1: string
@@ -35,7 +39,7 @@ tests/cases/compiler/excessPropertyCheckWithUnions.ts(40,1): error TS2322: Type
 !!! error TS2322:   Object literal may only specify known properties, and 'a1' does not exist in type '{ tag: "T"; }'.
     wrong = { tag: "A", d20: 12 }
                         ~~~~~~~
-!!! error TS2322: Type '{ tag: "A"; d20: 12; }' is not assignable to type 'ADT'.
+!!! error TS2322: Type '{ tag: "A"; d20: number; }' is not assignable to type 'ADT'.
 !!! error TS2322:   Object literal may only specify known properties, and 'd20' does not exist in type '{ tag: "A"; a1: string; }'.
     wrong = { tag: "D" }
     ~~~~~
@@ -93,9 +97,15 @@ tests/cases/compiler/excessPropertyCheckWithUnions.ts(40,1): error TS2322: Type
         | { b: 3, third: string }
     let over: Overlapping
     
-    // these two are not reported because there are two discriminant properties
+    // these two are still errors despite their doubled up discriminants
     over = { a: 1, b: 1, first: "ok", second: "error" }
+                                      ~~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ a: 1; b: 1; first: string; second: string; }' is not assignable to type 'Overlapping'.
+!!! error TS2322:   Object literal may only specify known properties, and 'second' does not exist in type '{ a: 1; b: 1; first: string; }'.
     over = { a: 1, b: 1, first: "ok", third: "error" }
+                                      ~~~~~~~~~~~~~~
+!!! error TS2322: Type '{ a: 1; b: 1; first: string; third: string; }' is not assignable to type 'Overlapping'.
+!!! error TS2322:   Object literal may only specify known properties, and 'third' does not exist in type '{ a: 1; b: 1; first: string; }'.
     
     // Freshness disappears after spreading a union
     declare let t0: { a: any, b: any } | { d: any, e: any }
diff --git a/tests/baselines/reference/excessPropertyCheckWithUnions.js b/tests/baselines/reference/excessPropertyCheckWithUnions.js
index c6b45123cce..a20983e4b08 100644
--- a/tests/baselines/reference/excessPropertyCheckWithUnions.js
+++ b/tests/baselines/reference/excessPropertyCheckWithUnions.js
@@ -46,7 +46,7 @@ type Overlapping =
     | { b: 3, third: string }
 let over: Overlapping
 
-// these two are not reported because there are two discriminant properties
+// these two are still errors despite their doubled up discriminants
 over = { a: 1, b: 1, first: "ok", second: "error" }
 over = { a: 1, b: 1, first: "ok", third: "error" }
 
@@ -84,7 +84,7 @@ amb = { tag: "A", y: 12, extra: 12 };
 amb = { tag: "A" };
 amb = { tag: "A", z: true };
 var over;
-// these two are not reported because there are two discriminant properties
+// these two are still errors despite their doubled up discriminants
 over = { a: 1, b: 1, first: "ok", second: "error" };
 over = { a: 1, b: 1, first: "ok", third: "error" };
 var t2 = __assign({}, t1);
diff --git a/tests/baselines/reference/excessPropertyCheckWithUnions.symbols b/tests/baselines/reference/excessPropertyCheckWithUnions.symbols
index 7778c6bf216..381681de384 100644
--- a/tests/baselines/reference/excessPropertyCheckWithUnions.symbols
+++ b/tests/baselines/reference/excessPropertyCheckWithUnions.symbols
@@ -127,7 +127,7 @@ let over: Overlapping
 >over : Symbol(over, Decl(excessPropertyCheckWithUnions.ts, 45, 3))
 >Overlapping : Symbol(Overlapping, Decl(excessPropertyCheckWithUnions.ts, 39, 27))
 
-// these two are not reported because there are two discriminant properties
+// these two are still errors despite their doubled up discriminants
 over = { a: 1, b: 1, first: "ok", second: "error" }
 >over : Symbol(over, Decl(excessPropertyCheckWithUnions.ts, 45, 3))
 >a : Symbol(a, Decl(excessPropertyCheckWithUnions.ts, 48, 8))
diff --git a/tests/baselines/reference/excessPropertyCheckWithUnions.types b/tests/baselines/reference/excessPropertyCheckWithUnions.types
index 78f5c025b38..212eccbe2ff 100644
--- a/tests/baselines/reference/excessPropertyCheckWithUnions.types
+++ b/tests/baselines/reference/excessPropertyCheckWithUnions.types
@@ -29,9 +29,9 @@ let wrong: ADT = { tag: "T", a1: "extra" }
 >"extra" : "extra"
 
 wrong = { tag: "A", d20: 12 }
->wrong = { tag: "A", d20: 12 } : { tag: "A"; d20: 12; }
+>wrong = { tag: "A", d20: 12 } : { tag: "A"; d20: number; }
 >wrong : ADT
->{ tag: "A", d20: 12 } : { tag: "A"; d20: 12; }
+>{ tag: "A", d20: 12 } : { tag: "A"; d20: number; }
 >tag : string
 >"A" : "A"
 >d20 : number
@@ -167,7 +167,7 @@ let over: Overlapping
 >over : Overlapping
 >Overlapping : Overlapping
 
-// these two are not reported because there are two discriminant properties
+// these two are still errors despite their doubled up discriminants
 over = { a: 1, b: 1, first: "ok", second: "error" }
 >over = { a: 1, b: 1, first: "ok", second: "error" } : { a: 1; b: 1; first: string; second: string; }
 >over : Overlapping
diff --git a/tests/baselines/reference/exportDefaultAlias_excludesEverything.errors.txt b/tests/baselines/reference/exportDefaultAlias_excludesEverything.errors.txt
new file mode 100644
index 00000000000..9181278db20
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultAlias_excludesEverything.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/exportDefaultAlias_excludesEverything.ts(1,26): error TS2528: A module cannot have multiple default exports.
+tests/cases/compiler/exportDefaultAlias_excludesEverything.ts(3,16): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/compiler/exportDefaultAlias_excludesEverything.ts (2 errors) ====
+    export default interface A {}
+                             ~
+!!! error TS2528: A module cannot have multiple default exports.
+    interface B {}
+    export default B;
+                   ~
+!!! error TS2528: A module cannot have multiple default exports.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/exportDefaultAlias_excludesEverything.js b/tests/baselines/reference/exportDefaultAlias_excludesEverything.js
new file mode 100644
index 00000000000..27f75954c14
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultAlias_excludesEverything.js
@@ -0,0 +1,9 @@
+//// [exportDefaultAlias_excludesEverything.ts]
+export default interface A {}
+interface B {}
+export default B;
+
+
+//// [exportDefaultAlias_excludesEverything.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/baselines/reference/exportDefaultAlias_excludesEverything.symbols b/tests/baselines/reference/exportDefaultAlias_excludesEverything.symbols
new file mode 100644
index 00000000000..73b403e0da1
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultAlias_excludesEverything.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/exportDefaultAlias_excludesEverything.ts ===
+export default interface A {}
+>A : Symbol(A, Decl(exportDefaultAlias_excludesEverything.ts, 0, 0))
+
+interface B {}
+>B : Symbol(B, Decl(exportDefaultAlias_excludesEverything.ts, 0, 29))
+
+export default B;
+>B : Symbol(B, Decl(exportDefaultAlias_excludesEverything.ts, 0, 29))
+
diff --git a/tests/baselines/reference/exportDefaultAlias_excludesEverything.types b/tests/baselines/reference/exportDefaultAlias_excludesEverything.types
new file mode 100644
index 00000000000..cd9dd06f817
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultAlias_excludesEverything.types
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/exportDefaultAlias_excludesEverything.ts ===
+export default interface A {}
+>A : A
+
+interface B {}
+>B : B
+
+export default B;
+>B : B
+
diff --git a/tests/baselines/reference/exportDefaultParenthesize.js b/tests/baselines/reference/exportDefaultParenthesize.js
new file mode 100644
index 00000000000..31fe9b6da3e
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesize.js
@@ -0,0 +1,72 @@
+//// [tests/cases/compiler/exportDefaultParenthesize.ts] ////
+
+//// [commalist.ts]
+export default {
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+};
+
+//// [comma.ts]
+export default {
+    ['foo']: 42
+};
+
+//// [functionexpression.ts]
+export default () => 42;
+
+
+//// [commalist.js]
+export default (_a = {},
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a['foo' + ''] = 42,
+    _a);
+var _a;
+//// [comma.js]
+export default (_a = {},
+    _a['foo'] = 42,
+    _a);
+var _a;
+//// [functionexpression.js]
+export default (function () { return 42; });
diff --git a/tests/baselines/reference/exportDefaultParenthesize.symbols b/tests/baselines/reference/exportDefaultParenthesize.symbols
new file mode 100644
index 00000000000..684138ebb3b
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesize.symbols
@@ -0,0 +1,38 @@
+=== tests/cases/compiler/commalist.ts ===
+export default {
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.    ['foo'+'']: 42,
+No type information for this code.};
+No type information for this code.
+No type information for this code.=== tests/cases/compiler/comma.ts ===
+export default {
+    ['foo']: 42
+>'foo' : Symbol(['foo'], Decl(comma.ts, 0, 16))
+
+};
+
+=== tests/cases/compiler/functionexpression.ts ===
+export default () => 42;
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/exportDefaultParenthesize.types b/tests/baselines/reference/exportDefaultParenthesize.types
new file mode 100644
index 00000000000..43e016a9ea0
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesize.types
@@ -0,0 +1,159 @@
+=== tests/cases/compiler/commalist.ts ===
+export default {
+>{    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,    ['foo'+'']: 42,} : { [x: string]: number; }
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+    ['foo'+'']: 42,
+>'foo'+'' : string
+>'foo' : "foo"
+>'' : ""
+>42 : 42
+
+};
+
+=== tests/cases/compiler/comma.ts ===
+export default {
+>{    ['foo']: 42} : { ['foo']: number; }
+
+    ['foo']: 42
+>'foo' : "foo"
+>42 : 42
+
+};
+
+=== tests/cases/compiler/functionexpression.ts ===
+export default () => 42;
+>() => 42 : () => number
+>42 : 42
+
diff --git a/tests/baselines/reference/exportDefaultParenthesizeES6.js b/tests/baselines/reference/exportDefaultParenthesizeES6.js
new file mode 100644
index 00000000000..7d7d686e251
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesizeES6.js
@@ -0,0 +1,6 @@
+//// [classexpr.ts]
+export default (class Foo {} as any);
+
+//// [classexpr.js]
+export default (class Foo {
+});
diff --git a/tests/baselines/reference/exportDefaultParenthesizeES6.symbols b/tests/baselines/reference/exportDefaultParenthesizeES6.symbols
new file mode 100644
index 00000000000..bddaccade51
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesizeES6.symbols
@@ -0,0 +1,4 @@
+=== tests/cases/compiler/classexpr.ts ===
+export default (class Foo {} as any);
+>Foo : Symbol(Foo, Decl(classexpr.ts, 0, 16))
+
diff --git a/tests/baselines/reference/exportDefaultParenthesizeES6.types b/tests/baselines/reference/exportDefaultParenthesizeES6.types
new file mode 100644
index 00000000000..a2f76670b23
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultParenthesizeES6.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/classexpr.ts ===
+export default (class Foo {} as any);
+>(class Foo {} as any) : any
+>class Foo {} as any : any
+>class Foo {} : typeof Foo
+>Foo : typeof Foo
+
diff --git a/tests/baselines/reference/exportEqualsAmd.js b/tests/baselines/reference/exportEqualsAmd.js
index 8b66b8896e3..e76b9dbacc8 100644
--- a/tests/baselines/reference/exportEqualsAmd.js
+++ b/tests/baselines/reference/exportEqualsAmd.js
@@ -5,5 +5,5 @@ export = { ["hi"]: "there" };
 define(["require", "exports"], function (require, exports) {
     "use strict";
     var _a;
-    return _a = {}, _a["hi"] = "there", _a;
+    return (_a = {}, _a["hi"] = "there", _a);
 });
diff --git a/tests/baselines/reference/exportEqualsUmd.js b/tests/baselines/reference/exportEqualsUmd.js
index 2201f2b8407..1d8a99717ed 100644
--- a/tests/baselines/reference/exportEqualsUmd.js
+++ b/tests/baselines/reference/exportEqualsUmd.js
@@ -13,5 +13,5 @@ export = { ["hi"]: "there" };
 })(function (require, exports) {
     "use strict";
     var _a;
-    return _a = {}, _a["hi"] = "there", _a;
+    return (_a = {}, _a["hi"] = "there", _a);
 });
diff --git a/tests/baselines/reference/exportSpecifierForAGlobal.errors.txt b/tests/baselines/reference/exportSpecifierForAGlobal.errors.txt
index d2f103a91fa..20a1c9a7d41 100644
--- a/tests/baselines/reference/exportSpecifierForAGlobal.errors.txt
+++ b/tests/baselines/reference/exportSpecifierForAGlobal.errors.txt
@@ -1,14 +1,17 @@
 tests/cases/compiler/b.ts(1,9): error TS2661: Cannot export 'X'. Only local declarations can be exported from a module.
+tests/cases/compiler/b.ts(2,17): error TS4060: Return type of exported function has or is using private name 'X'.
 
 
 ==== tests/cases/compiler/a.d.ts (0 errors) ====
     declare class X { }
     
-==== tests/cases/compiler/b.ts (1 errors) ====
+==== tests/cases/compiler/b.ts (2 errors) ====
     export {X};
             ~
 !!! error TS2661: Cannot export 'X'. Only local declarations can be exported from a module.
     export function f() {
+                    ~
+!!! error TS4060: Return type of exported function has or is using private name 'X'.
         var x: X;
         return x;
     } 
diff --git a/tests/baselines/reference/exportSpecifierForAGlobal.js b/tests/baselines/reference/exportSpecifierForAGlobal.js
index 6023b7c7f14..9f12241cbd1 100644
--- a/tests/baselines/reference/exportSpecifierForAGlobal.js
+++ b/tests/baselines/reference/exportSpecifierForAGlobal.js
@@ -19,8 +19,3 @@ function f() {
     return x;
 }
 exports.f = f;
-
-
-//// [b.d.ts]
-export { X };
-export declare function f(): X;
diff --git a/tests/baselines/reference/exportsAndImports3-amd.symbols b/tests/baselines/reference/exportsAndImports3-amd.symbols
index f71014281c2..edc5d5c2e4e 100644
--- a/tests/baselines/reference/exportsAndImports3-amd.symbols
+++ b/tests/baselines/reference/exportsAndImports3-amd.symbols
@@ -15,17 +15,17 @@ export enum E {
 >E : Symbol(E, Decl(t1.ts, 5, 1))
 
     A, B, C
->A : Symbol(E.A, Decl(t1.ts, 6, 15))
->B : Symbol(E.B, Decl(t1.ts, 7, 6))
->C : Symbol(E.C, Decl(t1.ts, 7, 9))
+>A : Symbol(E1.A, Decl(t1.ts, 6, 15))
+>B : Symbol(E1.B, Decl(t1.ts, 7, 6))
+>C : Symbol(E1.C, Decl(t1.ts, 7, 9))
 }
 export const enum D {
 >D : Symbol(D, Decl(t1.ts, 8, 1))
 
     A, B, C
->A : Symbol(D.A, Decl(t1.ts, 9, 21))
->B : Symbol(D.B, Decl(t1.ts, 10, 6))
->C : Symbol(D.C, Decl(t1.ts, 10, 9))
+>A : Symbol(D1.A, Decl(t1.ts, 9, 21))
+>B : Symbol(D1.B, Decl(t1.ts, 10, 6))
+>C : Symbol(D1.C, Decl(t1.ts, 10, 9))
 }
 export module M {
 >M : Symbol(M, Decl(t1.ts, 11, 1))
diff --git a/tests/baselines/reference/exportsAndImports3-es6.symbols b/tests/baselines/reference/exportsAndImports3-es6.symbols
index f71014281c2..edc5d5c2e4e 100644
--- a/tests/baselines/reference/exportsAndImports3-es6.symbols
+++ b/tests/baselines/reference/exportsAndImports3-es6.symbols
@@ -15,17 +15,17 @@ export enum E {
 >E : Symbol(E, Decl(t1.ts, 5, 1))
 
     A, B, C
->A : Symbol(E.A, Decl(t1.ts, 6, 15))
->B : Symbol(E.B, Decl(t1.ts, 7, 6))
->C : Symbol(E.C, Decl(t1.ts, 7, 9))
+>A : Symbol(E1.A, Decl(t1.ts, 6, 15))
+>B : Symbol(E1.B, Decl(t1.ts, 7, 6))
+>C : Symbol(E1.C, Decl(t1.ts, 7, 9))
 }
 export const enum D {
 >D : Symbol(D, Decl(t1.ts, 8, 1))
 
     A, B, C
->A : Symbol(D.A, Decl(t1.ts, 9, 21))
->B : Symbol(D.B, Decl(t1.ts, 10, 6))
->C : Symbol(D.C, Decl(t1.ts, 10, 9))
+>A : Symbol(D1.A, Decl(t1.ts, 9, 21))
+>B : Symbol(D1.B, Decl(t1.ts, 10, 6))
+>C : Symbol(D1.C, Decl(t1.ts, 10, 9))
 }
 export module M {
 >M : Symbol(M, Decl(t1.ts, 11, 1))
diff --git a/tests/baselines/reference/exportsAndImports3.symbols b/tests/baselines/reference/exportsAndImports3.symbols
index f71014281c2..edc5d5c2e4e 100644
--- a/tests/baselines/reference/exportsAndImports3.symbols
+++ b/tests/baselines/reference/exportsAndImports3.symbols
@@ -15,17 +15,17 @@ export enum E {
 >E : Symbol(E, Decl(t1.ts, 5, 1))
 
     A, B, C
->A : Symbol(E.A, Decl(t1.ts, 6, 15))
->B : Symbol(E.B, Decl(t1.ts, 7, 6))
->C : Symbol(E.C, Decl(t1.ts, 7, 9))
+>A : Symbol(E1.A, Decl(t1.ts, 6, 15))
+>B : Symbol(E1.B, Decl(t1.ts, 7, 6))
+>C : Symbol(E1.C, Decl(t1.ts, 7, 9))
 }
 export const enum D {
 >D : Symbol(D, Decl(t1.ts, 8, 1))
 
     A, B, C
->A : Symbol(D.A, Decl(t1.ts, 9, 21))
->B : Symbol(D.B, Decl(t1.ts, 10, 6))
->C : Symbol(D.C, Decl(t1.ts, 10, 9))
+>A : Symbol(D1.A, Decl(t1.ts, 9, 21))
+>B : Symbol(D1.B, Decl(t1.ts, 10, 6))
+>C : Symbol(D1.C, Decl(t1.ts, 10, 9))
 }
 export module M {
 >M : Symbol(M, Decl(t1.ts, 11, 1))
diff --git a/tests/baselines/reference/fixSignatureCaching.types b/tests/baselines/reference/fixSignatureCaching.types
index 6f87f563707..781912544e2 100644
--- a/tests/baselines/reference/fixSignatureCaching.types
+++ b/tests/baselines/reference/fixSignatureCaching.types
@@ -866,9 +866,9 @@ define(function () {
 >'UnknownMobile' : "UnknownMobile"
 
     isArray = ('isArray' in Array) ?
->isArray = ('isArray' in Array) ?        Array.isArray : function (value) { return Object.prototype.toString.call(value) === '[object Array]'; } : (value: any) => boolean
+>isArray = ('isArray' in Array) ?        Array.isArray : function (value) { return Object.prototype.toString.call(value) === '[object Array]'; } : (arg: any) => arg is any[]
 >isArray : any
->('isArray' in Array) ?        Array.isArray : function (value) { return Object.prototype.toString.call(value) === '[object Array]'; } : (value: any) => boolean
+>('isArray' in Array) ?        Array.isArray : function (value) { return Object.prototype.toString.call(value) === '[object Array]'; } : (arg: any) => arg is any[]
 >('isArray' in Array) : boolean
 >'isArray' in Array : boolean
 >'isArray' : "isArray"
diff --git a/tests/baselines/reference/freshLiteralTypesInIntersections.js b/tests/baselines/reference/freshLiteralTypesInIntersections.js
new file mode 100644
index 00000000000..633a2200380
--- /dev/null
+++ b/tests/baselines/reference/freshLiteralTypesInIntersections.js
@@ -0,0 +1,13 @@
+//// [freshLiteralTypesInIntersections.ts]
+// Repro from #19657
+
+declare function func<A extends string, B extends A>(a: A, b: B[]): (ab: A & B) => void;
+const q = func("x" as "x" | "y", ["x"]);
+q("x");
+
+
+//// [freshLiteralTypesInIntersections.js]
+"use strict";
+// Repro from #19657
+var q = func("x", ["x"]);
+q("x");
diff --git a/tests/baselines/reference/freshLiteralTypesInIntersections.symbols b/tests/baselines/reference/freshLiteralTypesInIntersections.symbols
new file mode 100644
index 00000000000..b16f90407b4
--- /dev/null
+++ b/tests/baselines/reference/freshLiteralTypesInIntersections.symbols
@@ -0,0 +1,23 @@
+=== tests/cases/compiler/freshLiteralTypesInIntersections.ts ===
+// Repro from #19657
+
+declare function func<A extends string, B extends A>(a: A, b: B[]): (ab: A & B) => void;
+>func : Symbol(func, Decl(freshLiteralTypesInIntersections.ts, 0, 0))
+>A : Symbol(A, Decl(freshLiteralTypesInIntersections.ts, 2, 22))
+>B : Symbol(B, Decl(freshLiteralTypesInIntersections.ts, 2, 39))
+>A : Symbol(A, Decl(freshLiteralTypesInIntersections.ts, 2, 22))
+>a : Symbol(a, Decl(freshLiteralTypesInIntersections.ts, 2, 53))
+>A : Symbol(A, Decl(freshLiteralTypesInIntersections.ts, 2, 22))
+>b : Symbol(b, Decl(freshLiteralTypesInIntersections.ts, 2, 58))
+>B : Symbol(B, Decl(freshLiteralTypesInIntersections.ts, 2, 39))
+>ab : Symbol(ab, Decl(freshLiteralTypesInIntersections.ts, 2, 69))
+>A : Symbol(A, Decl(freshLiteralTypesInIntersections.ts, 2, 22))
+>B : Symbol(B, Decl(freshLiteralTypesInIntersections.ts, 2, 39))
+
+const q = func("x" as "x" | "y", ["x"]);
+>q : Symbol(q, Decl(freshLiteralTypesInIntersections.ts, 3, 5))
+>func : Symbol(func, Decl(freshLiteralTypesInIntersections.ts, 0, 0))
+
+q("x");
+>q : Symbol(q, Decl(freshLiteralTypesInIntersections.ts, 3, 5))
+
diff --git a/tests/baselines/reference/freshLiteralTypesInIntersections.types b/tests/baselines/reference/freshLiteralTypesInIntersections.types
new file mode 100644
index 00000000000..b693a8c2c3f
--- /dev/null
+++ b/tests/baselines/reference/freshLiteralTypesInIntersections.types
@@ -0,0 +1,30 @@
+=== tests/cases/compiler/freshLiteralTypesInIntersections.ts ===
+// Repro from #19657
+
+declare function func<A extends string, B extends A>(a: A, b: B[]): (ab: A & B) => void;
+>func : <A extends string, B extends A>(a: A, b: B[]) => (ab: A & B) => void
+>A : A
+>B : B
+>A : A
+>a : A
+>A : A
+>b : B[]
+>B : B
+>ab : A & B
+>A : A
+>B : B
+
+const q = func("x" as "x" | "y", ["x"]);
+>q : (ab: "x") => void
+>func("x" as "x" | "y", ["x"]) : (ab: "x") => void
+>func : <A extends string, B extends A>(a: A, b: B[]) => (ab: A & B) => void
+>"x" as "x" | "y" : "x" | "y"
+>"x" : "x"
+>["x"] : "x"[]
+>"x" : "x"
+
+q("x");
+>q("x") : void
+>q : (ab: "x") => void
+>"x" : "x"
+
diff --git a/tests/baselines/reference/functionConstraintSatisfaction.js b/tests/baselines/reference/functionConstraintSatisfaction.js
index fc8a2be88a7..f24fd32aff6 100644
--- a/tests/baselines/reference/functionConstraintSatisfaction.js
+++ b/tests/baselines/reference/functionConstraintSatisfaction.js
@@ -108,4 +108,4 @@ function foo2(x, y) {
 //function foo2<T extends { (): void }, U extends T>(x: T, y: U) {
 //    foo(x);
 //    foo(y);
-//} 
+//}
diff --git a/tests/baselines/reference/genericCallWithObjectTypeArgsAndNumericIndexer.js b/tests/baselines/reference/genericCallWithObjectTypeArgsAndNumericIndexer.js
index f300e3a8093..27e4093d9c7 100644
--- a/tests/baselines/reference/genericCallWithObjectTypeArgsAndNumericIndexer.js
+++ b/tests/baselines/reference/genericCallWithObjectTypeArgsAndNumericIndexer.js
@@ -63,4 +63,4 @@ function other3(arg) {
 //    var d = r2[1];
 //    // BUG 821629
 //    //var u: U = r2[1]; // ok
-//} 
+//}
diff --git a/tests/baselines/reference/genericCallWithObjectTypeArgsAndStringIndexer.js b/tests/baselines/reference/genericCallWithObjectTypeArgsAndStringIndexer.js
index eee87caf3de..ee33746b152 100644
--- a/tests/baselines/reference/genericCallWithObjectTypeArgsAndStringIndexer.js
+++ b/tests/baselines/reference/genericCallWithObjectTypeArgsAndStringIndexer.js
@@ -64,4 +64,4 @@ function other3(arg) {
 //    var d: Date = r2['hm']; // ok
 //    // BUG 821629
 //    //var u: U = r2['hm']; // ok
-//} 
+//}
diff --git a/tests/baselines/reference/genericCallWithTupleType.errors.txt b/tests/baselines/reference/genericCallWithTupleType.errors.txt
index 617c4f7159b..65920596c45 100644
--- a/tests/baselines/reference/genericCallWithTupleType.errors.txt
+++ b/tests/baselines/reference/genericCallWithTupleType.errors.txt
@@ -1,8 +1,6 @@
 tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(12,1): error TS2322: Type '[string, number, boolean, boolean]' is not assignable to type '[string, number]'.
-  Types of property 'pop' are incompatible.
-    Type '() => string | number | boolean' is not assignable to type '() => string | number'.
-      Type 'string | number | boolean' is not assignable to type 'string | number'.
-        Type 'true' is not assignable to type 'string | number'.
+  Types of property 'length' are incompatible.
+    Type '4' is not assignable to type '2'.
 tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(14,1): error TS2322: Type '{ a: string; }' is not assignable to type 'string | number'.
   Type '{ a: string; }' is not assignable to type 'number'.
 tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTupleType.ts(22,1): error TS2322: Type '[number, string]' is not assignable to type '[string, number]'.
@@ -28,10 +26,8 @@ tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithTup
     i1.tuple1 = ["foo", 5, false, true];
     ~~~~~~~~~
 !!! error TS2322: Type '[string, number, boolean, boolean]' is not assignable to type '[string, number]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => string | number | boolean' is not assignable to type '() => string | number'.
-!!! error TS2322:       Type 'string | number | boolean' is not assignable to type 'string | number'.
-!!! error TS2322:         Type 'true' is not assignable to type 'string | number'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '4' is not assignable to type '2'.
     var e3 = i1.tuple1[2];  // {}
     i1.tuple1[3] = { a: "string" };
     ~~~~~~~~~~~~
diff --git a/tests/baselines/reference/genericTypeAliases.js b/tests/baselines/reference/genericTypeAliases.js
index 8218f5c886c..282fd9868a9 100644
--- a/tests/baselines/reference/genericTypeAliases.js
+++ b/tests/baselines/reference/genericTypeAliases.js
@@ -40,12 +40,12 @@ type Strange<T> = string;  // Type parameter not used
 var s: Strange<number>;
 s = "hello";
 
-interface Tuple<A, B> {
+interface AB<A, B> {
     a: A;
     b: B;
 }
 
-type Pair<T> = Tuple<T, T>;
+type Pair<T> = AB<T, T>;
 
 interface TaggedPair<T> extends Pair<T> {
     tag: string;
diff --git a/tests/baselines/reference/genericTypeAliases.symbols b/tests/baselines/reference/genericTypeAliases.symbols
index d5f68ec0615..521afe800b3 100644
--- a/tests/baselines/reference/genericTypeAliases.symbols
+++ b/tests/baselines/reference/genericTypeAliases.symbols
@@ -124,29 +124,29 @@ var s: Strange<number>;
 s = "hello";
 >s : Symbol(s, Decl(genericTypeAliases.ts, 38, 3))
 
-interface Tuple<A, B> {
->Tuple : Symbol(Tuple, Decl(genericTypeAliases.ts, 39, 12))
->A : Symbol(A, Decl(genericTypeAliases.ts, 41, 16))
->B : Symbol(B, Decl(genericTypeAliases.ts, 41, 18))
+interface AB<A, B> {
+>AB : Symbol(AB, Decl(genericTypeAliases.ts, 39, 12))
+>A : Symbol(A, Decl(genericTypeAliases.ts, 41, 13))
+>B : Symbol(B, Decl(genericTypeAliases.ts, 41, 15))
 
     a: A;
->a : Symbol(Tuple.a, Decl(genericTypeAliases.ts, 41, 23))
->A : Symbol(A, Decl(genericTypeAliases.ts, 41, 16))
+>a : Symbol(AB.a, Decl(genericTypeAliases.ts, 41, 20))
+>A : Symbol(A, Decl(genericTypeAliases.ts, 41, 13))
 
     b: B;
->b : Symbol(Tuple.b, Decl(genericTypeAliases.ts, 42, 9))
->B : Symbol(B, Decl(genericTypeAliases.ts, 41, 18))
+>b : Symbol(AB.b, Decl(genericTypeAliases.ts, 42, 9))
+>B : Symbol(B, Decl(genericTypeAliases.ts, 41, 15))
 }
 
-type Pair<T> = Tuple<T, T>;
+type Pair<T> = AB<T, T>;
 >Pair : Symbol(Pair, Decl(genericTypeAliases.ts, 44, 1))
 >T : Symbol(T, Decl(genericTypeAliases.ts, 46, 10))
->Tuple : Symbol(Tuple, Decl(genericTypeAliases.ts, 39, 12))
+>AB : Symbol(AB, Decl(genericTypeAliases.ts, 39, 12))
 >T : Symbol(T, Decl(genericTypeAliases.ts, 46, 10))
 >T : Symbol(T, Decl(genericTypeAliases.ts, 46, 10))
 
 interface TaggedPair<T> extends Pair<T> {
->TaggedPair : Symbol(TaggedPair, Decl(genericTypeAliases.ts, 46, 27))
+>TaggedPair : Symbol(TaggedPair, Decl(genericTypeAliases.ts, 46, 24))
 >T : Symbol(T, Decl(genericTypeAliases.ts, 48, 21))
 >Pair : Symbol(Pair, Decl(genericTypeAliases.ts, 44, 1))
 >T : Symbol(T, Decl(genericTypeAliases.ts, 48, 21))
@@ -157,17 +157,17 @@ interface TaggedPair<T> extends Pair<T> {
 
 var p: TaggedPair<number>;
 >p : Symbol(p, Decl(genericTypeAliases.ts, 52, 3))
->TaggedPair : Symbol(TaggedPair, Decl(genericTypeAliases.ts, 46, 27))
+>TaggedPair : Symbol(TaggedPair, Decl(genericTypeAliases.ts, 46, 24))
 
 p.a = 1;
->p.a : Symbol(Tuple.a, Decl(genericTypeAliases.ts, 41, 23))
+>p.a : Symbol(AB.a, Decl(genericTypeAliases.ts, 41, 20))
 >p : Symbol(p, Decl(genericTypeAliases.ts, 52, 3))
->a : Symbol(Tuple.a, Decl(genericTypeAliases.ts, 41, 23))
+>a : Symbol(AB.a, Decl(genericTypeAliases.ts, 41, 20))
 
 p.b = 2;
->p.b : Symbol(Tuple.b, Decl(genericTypeAliases.ts, 42, 9))
+>p.b : Symbol(AB.b, Decl(genericTypeAliases.ts, 42, 9))
 >p : Symbol(p, Decl(genericTypeAliases.ts, 52, 3))
->b : Symbol(Tuple.b, Decl(genericTypeAliases.ts, 42, 9))
+>b : Symbol(AB.b, Decl(genericTypeAliases.ts, 42, 9))
 
 p.tag = "test";
 >p.tag : Symbol(TaggedPair.tag, Decl(genericTypeAliases.ts, 48, 41))
diff --git a/tests/baselines/reference/genericTypeAliases.types b/tests/baselines/reference/genericTypeAliases.types
index b4c75841245..722347b0f72 100644
--- a/tests/baselines/reference/genericTypeAliases.types
+++ b/tests/baselines/reference/genericTypeAliases.types
@@ -158,8 +158,8 @@ s = "hello";
 >s : string
 >"hello" : "hello"
 
-interface Tuple<A, B> {
->Tuple : Tuple<A, B>
+interface AB<A, B> {
+>AB : AB<A, B>
 >A : A
 >B : B
 
@@ -172,17 +172,17 @@ interface Tuple<A, B> {
 >B : B
 }
 
-type Pair<T> = Tuple<T, T>;
->Pair : Tuple<T, T>
+type Pair<T> = AB<T, T>;
+>Pair : AB<T, T>
 >T : T
->Tuple : Tuple<A, B>
+>AB : AB<A, B>
 >T : T
 >T : T
 
 interface TaggedPair<T> extends Pair<T> {
 >TaggedPair : TaggedPair<T>
 >T : T
->Pair : Tuple<T, T>
+>Pair : AB<T, T>
 >T : T
 
     tag: string;
diff --git a/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt b/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
index c25aca342ca..e7ceb8acea2 100644
--- a/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
+++ b/tests/baselines/reference/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(1,18): error TS2300: Duplicate identifier '_'.
-tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(1,41): error TS2304: Cannot find name '_'.
+tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(1,41): error TS2709: Cannot use namespace '_' as a type.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(2,18): error TS2300: Duplicate identifier '_'.
-tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(2,34): error TS2304: Cannot find name '_'.
+tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(2,34): error TS2709: Cannot use namespace '_' as a type.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(4,16): error TS2300: Duplicate identifier '_'.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(15,15): error TS2300: Duplicate identifier '_'.
 tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(21,20): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
@@ -12,12 +12,12 @@ tests/cases/compiler/getAccessorWithImpliedReturnTypeAndFunctionClassMerge.ts(21
                      ~
 !!! error TS2300: Duplicate identifier '_'.
                                             ~
-!!! error TS2304: Cannot find name '_'.
+!!! error TS2709: Cannot use namespace '_' as a type.
     declare function _<T>(value: T): _<T>;
                      ~
 !!! error TS2300: Duplicate identifier '_'.
                                      ~
-!!! error TS2304: Cannot find name '_'.
+!!! error TS2709: Cannot use namespace '_' as a type.
     
     declare module _ {
                    ~
diff --git a/tests/baselines/reference/heterogeneousArrayLiterals.js b/tests/baselines/reference/heterogeneousArrayLiterals.js
index 499aa7e7818..46dee284ae9 100644
--- a/tests/baselines/reference/heterogeneousArrayLiterals.js
+++ b/tests/baselines/reference/heterogeneousArrayLiterals.js
@@ -268,4 +268,4 @@ function foo4(t, u) {
 //    var i = [u, base]; // Base[]
 //    var j = [u, derived]; // Derived[]
 //    var k: Base[] = [t, u];
-//} 
+//}
diff --git a/tests/baselines/reference/heterogeneousArrayLiterals.types b/tests/baselines/reference/heterogeneousArrayLiterals.types
index f1c5b6b8dfc..2655f7c2d71 100644
--- a/tests/baselines/reference/heterogeneousArrayLiterals.types
+++ b/tests/baselines/reference/heterogeneousArrayLiterals.types
@@ -22,13 +22,13 @@ var c = [1, '', null]; // {}[]
 
 var d = [{}, 1]; // {}[]
 >d : {}[]
->[{}, 1] : {}[]
+>[{}, 1] : (number | {})[]
 >{} : {}
 >1 : 1
 
 var e = [{}, Object]; // {}[]
 >e : {}[]
->[{}, Object] : {}[]
+>[{}, Object] : (ObjectConstructor | {})[]
 >{} : {}
 >Object : ObjectConstructor
 
@@ -48,7 +48,7 @@ var g = [[1], ['']]; // {}[]
 >'' : ""
 
 var h = [{ foo: 1, bar: '' }, { foo: 2 }]; // {foo: number}[]
->h : ({ foo: number; bar: string; } | { foo: number; })[]
+>h : ({ foo: number; bar: string; } | { foo: number; bar?: undefined; })[]
 >[{ foo: 1, bar: '' }, { foo: 2 }] : ({ foo: number; bar: string; } | { foo: number; })[]
 >{ foo: 1, bar: '' } : { foo: number; bar: string; }
 >foo : number
@@ -60,7 +60,7 @@ var h = [{ foo: 1, bar: '' }, { foo: 2 }]; // {foo: number}[]
 >2 : 2
 
 var i = [{ foo: 1, bar: '' }, { foo: '' }]; // {}[]
->i : ({ foo: number; bar: string; } | { foo: string; })[]
+>i : ({ foo: number; bar: string; } | { foo: string; bar?: undefined; })[]
 >[{ foo: 1, bar: '' }, { foo: '' }] : ({ foo: number; bar: string; } | { foo: string; })[]
 >{ foo: 1, bar: '' } : { foo: number; bar: string; }
 >foo : number
@@ -145,7 +145,7 @@ module Derived {
 >Derived : typeof Derived
 
     var h = [{ foo: base, basear: derived }, { foo: base }]; // {foo: Base}[]
->h : ({ foo: Base; basear: Derived; } | { foo: Base; })[]
+>h : ({ foo: Base; basear: Derived; } | { foo: Base; basear?: undefined; })[]
 >[{ foo: base, basear: derived }, { foo: base }] : ({ foo: Base; basear: Derived; } | { foo: Base; })[]
 >{ foo: base, basear: derived } : { foo: Base; basear: Derived; }
 >foo : Base
@@ -157,7 +157,7 @@ module Derived {
 >base : Base
 
     var i = [{ foo: base, basear: derived }, { foo: derived }]; // {foo: Derived}[]
->i : ({ foo: Base; basear: Derived; } | { foo: Derived; })[]
+>i : ({ foo: Base; basear: Derived; } | { foo: Derived; basear?: undefined; })[]
 >[{ foo: base, basear: derived }, { foo: derived }] : ({ foo: Base; basear: Derived; } | { foo: Derived; })[]
 >{ foo: base, basear: derived } : { foo: Base; basear: Derived; }
 >foo : Base
diff --git a/tests/baselines/reference/incompatibleTypes.types b/tests/baselines/reference/incompatibleTypes.types
index 053bf6bf099..d88a09a4b72 100644
--- a/tests/baselines/reference/incompatibleTypes.types
+++ b/tests/baselines/reference/incompatibleTypes.types
@@ -176,7 +176,7 @@ var o1: { a: { a: string; }; b: string; } = { e: 0, f: 0 };
 >0 : 0
 
 var a1 = [{ e: 0, f: 0 }, { e: 0, f: 0 }, { e: 0, g: 0 }];
->a1 : ({ e: number; f: number; } | { e: number; g: number; })[]
+>a1 : ({ e: number; f: number; g?: undefined; } | { e: number; g: number; f?: undefined; })[]
 >[{ e: 0, f: 0 }, { e: 0, f: 0 }, { e: 0, g: 0 }] : ({ e: number; f: number; } | { e: number; g: number; })[]
 >{ e: 0, f: 0 } : { e: number; f: number; }
 >e : number
diff --git a/tests/baselines/reference/innerTypeParameterShadowingOuterOne.js b/tests/baselines/reference/innerTypeParameterShadowingOuterOne.js
index 74354468e32..f566bbdd878 100644
--- a/tests/baselines/reference/innerTypeParameterShadowingOuterOne.js
+++ b/tests/baselines/reference/innerTypeParameterShadowingOuterOne.js
@@ -54,4 +54,4 @@ function f2() {
 //    }
 //    var x: U;
 //    x.getDate();
-//} 
+//}
diff --git a/tests/baselines/reference/innerTypeParameterShadowingOuterOne2.js b/tests/baselines/reference/innerTypeParameterShadowingOuterOne2.js
index 984584389f6..824061fce1f 100644
--- a/tests/baselines/reference/innerTypeParameterShadowingOuterOne2.js
+++ b/tests/baselines/reference/innerTypeParameterShadowingOuterOne2.js
@@ -75,4 +75,4 @@ var C2 = /** @class */ (function () {
 //        var x: U;
 //        x.getDate();
 //    }
-//} 
+//}
diff --git a/tests/baselines/reference/intersectionTypeInference3.js b/tests/baselines/reference/intersectionTypeInference3.js
new file mode 100644
index 00000000000..8a7db286ca2
--- /dev/null
+++ b/tests/baselines/reference/intersectionTypeInference3.js
@@ -0,0 +1,25 @@
+//// [intersectionTypeInference3.ts]
+// Repro from #19682
+
+type Nominal<Kind extends string, Type> = Type & {
+    [Symbol.species]: Kind;
+};
+
+type A = Nominal<'A', string>;
+
+declare const a: Set<A>;
+declare const b: Set<A>;
+
+const c1 = Array.from(a).concat(Array.from(b));
+
+// Simpler repro
+
+declare function from<T>(): T[];
+const c2: ReadonlyArray<A> = from();
+
+
+//// [intersectionTypeInference3.js]
+"use strict";
+// Repro from #19682
+const c1 = Array.from(a).concat(Array.from(b));
+const c2 = from();
diff --git a/tests/baselines/reference/intersectionTypeInference3.symbols b/tests/baselines/reference/intersectionTypeInference3.symbols
new file mode 100644
index 00000000000..3945cf64fb6
--- /dev/null
+++ b/tests/baselines/reference/intersectionTypeInference3.symbols
@@ -0,0 +1,57 @@
+=== tests/cases/conformance/types/intersection/intersectionTypeInference3.ts ===
+// Repro from #19682
+
+type Nominal<Kind extends string, Type> = Type & {
+>Nominal : Symbol(Nominal, Decl(intersectionTypeInference3.ts, 0, 0))
+>Kind : Symbol(Kind, Decl(intersectionTypeInference3.ts, 2, 13))
+>Type : Symbol(Type, Decl(intersectionTypeInference3.ts, 2, 33))
+>Type : Symbol(Type, Decl(intersectionTypeInference3.ts, 2, 33))
+
+    [Symbol.species]: Kind;
+>Symbol.species : Symbol(SymbolConstructor.species, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Symbol : Symbol(Symbol, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --), Decl(lib.es2015.symbol.d.ts, --, --))
+>species : Symbol(SymbolConstructor.species, Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>Kind : Symbol(Kind, Decl(intersectionTypeInference3.ts, 2, 13))
+
+};
+
+type A = Nominal<'A', string>;
+>A : Symbol(A, Decl(intersectionTypeInference3.ts, 4, 2))
+>Nominal : Symbol(Nominal, Decl(intersectionTypeInference3.ts, 0, 0))
+
+declare const a: Set<A>;
+>a : Symbol(a, Decl(intersectionTypeInference3.ts, 8, 13))
+>Set : Symbol(Set, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --))
+>A : Symbol(A, Decl(intersectionTypeInference3.ts, 4, 2))
+
+declare const b: Set<A>;
+>b : Symbol(b, Decl(intersectionTypeInference3.ts, 9, 13))
+>Set : Symbol(Set, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --))
+>A : Symbol(A, Decl(intersectionTypeInference3.ts, 4, 2))
+
+const c1 = Array.from(a).concat(Array.from(b));
+>c1 : Symbol(c1, Decl(intersectionTypeInference3.ts, 11, 5))
+>Array.from(a).concat : Symbol(Array.concat, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>a : Symbol(a, Decl(intersectionTypeInference3.ts, 8, 13))
+>concat : Symbol(Array.concat, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>b : Symbol(b, Decl(intersectionTypeInference3.ts, 9, 13))
+
+// Simpler repro
+
+declare function from<T>(): T[];
+>from : Symbol(from, Decl(intersectionTypeInference3.ts, 11, 47))
+>T : Symbol(T, Decl(intersectionTypeInference3.ts, 15, 22))
+>T : Symbol(T, Decl(intersectionTypeInference3.ts, 15, 22))
+
+const c2: ReadonlyArray<A> = from();
+>c2 : Symbol(c2, Decl(intersectionTypeInference3.ts, 16, 5))
+>ReadonlyArray : Symbol(ReadonlyArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>A : Symbol(A, Decl(intersectionTypeInference3.ts, 4, 2))
+>from : Symbol(from, Decl(intersectionTypeInference3.ts, 11, 47))
+
diff --git a/tests/baselines/reference/intersectionTypeInference3.types b/tests/baselines/reference/intersectionTypeInference3.types
new file mode 100644
index 00000000000..9fca37af8c1
--- /dev/null
+++ b/tests/baselines/reference/intersectionTypeInference3.types
@@ -0,0 +1,61 @@
+=== tests/cases/conformance/types/intersection/intersectionTypeInference3.ts ===
+// Repro from #19682
+
+type Nominal<Kind extends string, Type> = Type & {
+>Nominal : Nominal<Kind, Type>
+>Kind : Kind
+>Type : Type
+>Type : Type
+
+    [Symbol.species]: Kind;
+>Symbol.species : symbol
+>Symbol : SymbolConstructor
+>species : symbol
+>Kind : Kind
+
+};
+
+type A = Nominal<'A', string>;
+>A : Nominal<"A", string>
+>Nominal : Nominal<Kind, Type>
+
+declare const a: Set<A>;
+>a : Set<Nominal<"A", string>>
+>Set : Set<T>
+>A : Nominal<"A", string>
+
+declare const b: Set<A>;
+>b : Set<Nominal<"A", string>>
+>Set : Set<T>
+>A : Nominal<"A", string>
+
+const c1 = Array.from(a).concat(Array.from(b));
+>c1 : Nominal<"A", string>[]
+>Array.from(a).concat(Array.from(b)) : Nominal<"A", string>[]
+>Array.from(a).concat : { (...items: ReadonlyArray<Nominal<"A", string>>[]): Nominal<"A", string>[]; (...items: (Nominal<"A", string> | ReadonlyArray<Nominal<"A", string>>)[]): Nominal<"A", string>[]; }
+>Array.from(a) : Nominal<"A", string>[]
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array : ArrayConstructor
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
+>a : Set<Nominal<"A", string>>
+>concat : { (...items: ReadonlyArray<Nominal<"A", string>>[]): Nominal<"A", string>[]; (...items: (Nominal<"A", string> | ReadonlyArray<Nominal<"A", string>>)[]): Nominal<"A", string>[]; }
+>Array.from(b) : Nominal<"A", string>[]
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array : ArrayConstructor
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
+>b : Set<Nominal<"A", string>>
+
+// Simpler repro
+
+declare function from<T>(): T[];
+>from : <T>() => T[]
+>T : T
+>T : T
+
+const c2: ReadonlyArray<A> = from();
+>c2 : ReadonlyArray<Nominal<"A", string>>
+>ReadonlyArray : ReadonlyArray<T>
+>A : Nominal<"A", string>
+>from() : Nominal<"A", string>[]
+>from : <T>() => T[]
+
diff --git a/tests/baselines/reference/invariantGenericErrorElaboration.errors.txt b/tests/baselines/reference/invariantGenericErrorElaboration.errors.txt
new file mode 100644
index 00000000000..5142b665d71
--- /dev/null
+++ b/tests/baselines/reference/invariantGenericErrorElaboration.errors.txt
@@ -0,0 +1,54 @@
+tests/cases/compiler/invariantGenericErrorElaboration.ts(3,7): error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+  Types of property 'constraint' are incompatible.
+    Type 'Constraint<Num>' is not assignable to type 'Constraint<Runtype<any>>'.
+      Types of property 'constraint' are incompatible.
+        Type 'Constraint<Constraint<Num>>' is not assignable to type 'Constraint<Constraint<Runtype<any>>>'.
+          Types of property 'constraint' are incompatible.
+            Type 'Constraint<Constraint<Constraint<Num>>>' is not assignable to type 'Constraint<Constraint<Constraint<Runtype<any>>>>'.
+              Type 'Constraint<Constraint<Runtype<any>>>' is not assignable to type 'Constraint<Constraint<Num>>'.
+                Types of property 'underlying' are incompatible.
+                  Type 'Constraint<Runtype<any>>' is not assignable to type 'Constraint<Num>'.
+tests/cases/compiler/invariantGenericErrorElaboration.ts(4,17): error TS2345: Argument of type '{ foo: Num; }' is not assignable to parameter of type '{ [_: string]: Runtype<any>; }'.
+  Property 'foo' is incompatible with index signature.
+    Type 'Num' is not assignable to type 'Runtype<any>'.
+
+
+==== tests/cases/compiler/invariantGenericErrorElaboration.ts (2 errors) ====
+    // Repro from #19746
+    
+    const wat: Runtype<any> = Num;
+          ~~~
+!!! error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+!!! error TS2322:   Types of property 'constraint' are incompatible.
+!!! error TS2322:     Type 'Constraint<Num>' is not assignable to type 'Constraint<Runtype<any>>'.
+!!! error TS2322:       Types of property 'constraint' are incompatible.
+!!! error TS2322:         Type 'Constraint<Constraint<Num>>' is not assignable to type 'Constraint<Constraint<Runtype<any>>>'.
+!!! error TS2322:           Types of property 'constraint' are incompatible.
+!!! error TS2322:             Type 'Constraint<Constraint<Constraint<Num>>>' is not assignable to type 'Constraint<Constraint<Constraint<Runtype<any>>>>'.
+!!! error TS2322:               Type 'Constraint<Constraint<Runtype<any>>>' is not assignable to type 'Constraint<Constraint<Num>>'.
+!!! error TS2322:                 Types of property 'underlying' are incompatible.
+!!! error TS2322:                   Type 'Constraint<Runtype<any>>' is not assignable to type 'Constraint<Num>'.
+    const Foo = Obj({ foo: Num })
+                    ~~~~~~~~~~~~
+!!! error TS2345: Argument of type '{ foo: Num; }' is not assignable to parameter of type '{ [_: string]: Runtype<any>; }'.
+!!! error TS2345:   Property 'foo' is incompatible with index signature.
+!!! error TS2345:     Type 'Num' is not assignable to type 'Runtype<any>'.
+    
+    interface Runtype<A> {
+      constraint: Constraint<this>
+      witness: A
+    }
+    
+    interface Num extends Runtype<number> {
+      tag: 'number'
+    }
+    declare const Num: Num
+    
+    interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+    declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+    
+    interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+      underlying: A,
+      check: (x: A['witness']) => void,
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/invariantGenericErrorElaboration.js b/tests/baselines/reference/invariantGenericErrorElaboration.js
new file mode 100644
index 00000000000..253c4ab03b7
--- /dev/null
+++ b/tests/baselines/reference/invariantGenericErrorElaboration.js
@@ -0,0 +1,30 @@
+//// [invariantGenericErrorElaboration.ts]
+// Repro from #19746
+
+const wat: Runtype<any> = Num;
+const Foo = Obj({ foo: Num })
+
+interface Runtype<A> {
+  constraint: Constraint<this>
+  witness: A
+}
+
+interface Num extends Runtype<number> {
+  tag: 'number'
+}
+declare const Num: Num
+
+interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+
+interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+  underlying: A,
+  check: (x: A['witness']) => void,
+}
+
+
+//// [invariantGenericErrorElaboration.js]
+"use strict";
+// Repro from #19746
+var wat = Num;
+var Foo = Obj({ foo: Num });
diff --git a/tests/baselines/reference/invariantGenericErrorElaboration.symbols b/tests/baselines/reference/invariantGenericErrorElaboration.symbols
new file mode 100644
index 00000000000..9c141e5c27f
--- /dev/null
+++ b/tests/baselines/reference/invariantGenericErrorElaboration.symbols
@@ -0,0 +1,76 @@
+=== tests/cases/compiler/invariantGenericErrorElaboration.ts ===
+// Repro from #19746
+
+const wat: Runtype<any> = Num;
+>wat : Symbol(wat, Decl(invariantGenericErrorElaboration.ts, 2, 5))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>Num : Symbol(Num, Decl(invariantGenericErrorElaboration.ts, 8, 1), Decl(invariantGenericErrorElaboration.ts, 13, 13))
+
+const Foo = Obj({ foo: Num })
+>Foo : Symbol(Foo, Decl(invariantGenericErrorElaboration.ts, 3, 5))
+>Obj : Symbol(Obj, Decl(invariantGenericErrorElaboration.ts, 13, 22), Decl(invariantGenericErrorElaboration.ts, 15, 111))
+>foo : Symbol(foo, Decl(invariantGenericErrorElaboration.ts, 3, 17))
+>Num : Symbol(Num, Decl(invariantGenericErrorElaboration.ts, 8, 1), Decl(invariantGenericErrorElaboration.ts, 13, 13))
+
+interface Runtype<A> {
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 5, 18))
+
+  constraint: Constraint<this>
+>constraint : Symbol(Runtype.constraint, Decl(invariantGenericErrorElaboration.ts, 5, 22))
+>Constraint : Symbol(Constraint, Decl(invariantGenericErrorElaboration.ts, 16, 81))
+
+  witness: A
+>witness : Symbol(Runtype.witness, Decl(invariantGenericErrorElaboration.ts, 6, 30))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 5, 18))
+}
+
+interface Num extends Runtype<number> {
+>Num : Symbol(Num, Decl(invariantGenericErrorElaboration.ts, 8, 1), Decl(invariantGenericErrorElaboration.ts, 13, 13))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+
+  tag: 'number'
+>tag : Symbol(Num.tag, Decl(invariantGenericErrorElaboration.ts, 10, 39))
+}
+declare const Num: Num
+>Num : Symbol(Num, Decl(invariantGenericErrorElaboration.ts, 8, 1), Decl(invariantGenericErrorElaboration.ts, 13, 13))
+>Num : Symbol(Num, Decl(invariantGenericErrorElaboration.ts, 8, 1), Decl(invariantGenericErrorElaboration.ts, 13, 13))
+
+interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+>Obj : Symbol(Obj, Decl(invariantGenericErrorElaboration.ts, 13, 22), Decl(invariantGenericErrorElaboration.ts, 15, 111))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 15, 14))
+>_ : Symbol(_, Decl(invariantGenericErrorElaboration.ts, 15, 27))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>K : Symbol(K, Decl(invariantGenericErrorElaboration.ts, 15, 75))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 15, 14))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 15, 14))
+>K : Symbol(K, Decl(invariantGenericErrorElaboration.ts, 15, 75))
+
+declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+>Obj : Symbol(Obj, Decl(invariantGenericErrorElaboration.ts, 13, 22), Decl(invariantGenericErrorElaboration.ts, 15, 111))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 16, 21))
+>_ : Symbol(_, Decl(invariantGenericErrorElaboration.ts, 16, 34))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>fields : Symbol(fields, Decl(invariantGenericErrorElaboration.ts, 16, 62))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 16, 21))
+>Obj : Symbol(Obj, Decl(invariantGenericErrorElaboration.ts, 13, 22), Decl(invariantGenericErrorElaboration.ts, 15, 111))
+>O : Symbol(O, Decl(invariantGenericErrorElaboration.ts, 16, 21))
+
+interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+>Constraint : Symbol(Constraint, Decl(invariantGenericErrorElaboration.ts, 16, 81))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 18, 21))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>Runtype : Symbol(Runtype, Decl(invariantGenericErrorElaboration.ts, 3, 29))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 18, 21))
+
+  underlying: A,
+>underlying : Symbol(Constraint.underlying, Decl(invariantGenericErrorElaboration.ts, 18, 76))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 18, 21))
+
+  check: (x: A['witness']) => void,
+>check : Symbol(Constraint.check, Decl(invariantGenericErrorElaboration.ts, 19, 16))
+>x : Symbol(x, Decl(invariantGenericErrorElaboration.ts, 20, 10))
+>A : Symbol(A, Decl(invariantGenericErrorElaboration.ts, 18, 21))
+}
+
diff --git a/tests/baselines/reference/invariantGenericErrorElaboration.types b/tests/baselines/reference/invariantGenericErrorElaboration.types
new file mode 100644
index 00000000000..2120c06d5fa
--- /dev/null
+++ b/tests/baselines/reference/invariantGenericErrorElaboration.types
@@ -0,0 +1,78 @@
+=== tests/cases/compiler/invariantGenericErrorElaboration.ts ===
+// Repro from #19746
+
+const wat: Runtype<any> = Num;
+>wat : Runtype<any>
+>Runtype : Runtype<A>
+>Num : Num
+
+const Foo = Obj({ foo: Num })
+>Foo : any
+>Obj({ foo: Num }) : any
+>Obj : <O extends { [_: string]: Runtype<any>; }>(fields: O) => Obj<O>
+>{ foo: Num } : { foo: Num; }
+>foo : Num
+>Num : Num
+
+interface Runtype<A> {
+>Runtype : Runtype<A>
+>A : A
+
+  constraint: Constraint<this>
+>constraint : Constraint<this>
+>Constraint : Constraint<A>
+
+  witness: A
+>witness : A
+>A : A
+}
+
+interface Num extends Runtype<number> {
+>Num : Num
+>Runtype : Runtype<A>
+
+  tag: 'number'
+>tag : "number"
+}
+declare const Num: Num
+>Num : Num
+>Num : Num
+
+interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+>Obj : Obj<O>
+>O : O
+>_ : _
+>Runtype : Runtype<A>
+>Runtype : Runtype<A>
+>K : K
+>O : O
+>O : O
+>K : K
+
+declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+>Obj : <O extends { [_: string]: Runtype<any>; }>(fields: O) => Obj<O>
+>O : O
+>_ : string
+>Runtype : Runtype<A>
+>fields : O
+>O : O
+>Obj : Obj<O>
+>O : O
+
+interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+>Constraint : Constraint<A>
+>A : A
+>Runtype : Runtype<A>
+>Runtype : Runtype<A>
+>A : A
+
+  underlying: A,
+>underlying : A
+>A : A
+
+  check: (x: A['witness']) => void,
+>check : (x: A["witness"]) => void
+>x : A["witness"]
+>A : A
+}
+
diff --git a/tests/baselines/reference/jsDocTags.baseline b/tests/baselines/reference/jsDocTags.baseline
index 4140fa6bfca..7f9e9fdce98 100644
--- a/tests/baselines/reference/jsDocTags.baseline
+++ b/tests/baselines/reference/jsDocTags.baseline
@@ -2,13 +2,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 981
+      "position": 977
     },
     "quickInfo": {
       "kind": "constructor",
       "kindModifiers": "",
       "textSpan": {
-        "start": 981,
+        "start": 977,
         "length": 3
       },
       "displayParts": [
@@ -78,19 +78,19 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 985
+      "position": 981
     }
   },
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 989
+      "position": 985
     },
     "quickInfo": {
       "kind": "class",
       "kindModifiers": "",
       "textSpan": {
-        "start": 989,
+        "start": 985,
         "length": 3
       },
       "displayParts": [
@@ -124,13 +124,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 993
+      "position": 989
     },
     "quickInfo": {
       "kind": "method",
       "kindModifiers": "static",
       "textSpan": {
-        "start": 993,
+        "start": 989,
         "length": 7
       },
       "displayParts": [
@@ -200,19 +200,19 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1001
+      "position": 997
     }
   },
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1008
+      "position": 1004
     },
     "quickInfo": {
       "kind": "method",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1008,
+        "start": 1004,
         "length": 7
       },
       "displayParts": [
@@ -277,19 +277,19 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1016
+      "position": 1012
     }
   },
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1023
+      "position": 1019
     },
     "quickInfo": {
       "kind": "method",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1023,
+        "start": 1019,
         "length": 7
       },
       "displayParts": [
@@ -343,25 +343,30 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "returns",
+          "text": "a value"
+        }
+      ]
     }
   },
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1031
+      "position": 1027
     }
   },
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1038
+      "position": 1034
     },
     "quickInfo": {
       "kind": "method",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1038,
+        "start": 1034,
         "length": 7
       },
       "displayParts": [
@@ -432,6 +437,14 @@
       ],
       "documentation": [],
       "tags": [
+        {
+          "name": "param",
+          "text": "foo A value."
+        },
+        {
+          "name": "returns",
+          "text": "Another value"
+        },
         {
           "name": "mytag",
           "text": ""
@@ -442,13 +455,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1053
+      "position": 1049
     },
     "quickInfo": {
       "kind": "property",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1053,
+        "start": 1049,
         "length": 9
       },
       "displayParts": [
@@ -505,13 +518,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1068
+      "position": 1064
     },
     "quickInfo": {
       "kind": "property",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1068,
+        "start": 1064,
         "length": 9
       },
       "displayParts": [
@@ -580,13 +593,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1083
+      "position": 1079
     },
     "quickInfo": {
       "kind": "method",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1083,
+        "start": 1079,
         "length": 7
       },
       "displayParts": [
@@ -651,13 +664,13 @@
   {
     "marker": {
       "fileName": "/tests/cases/fourslash/jsDocTags.ts",
-      "position": 1104
+      "position": 1100
     },
     "quickInfo": {
       "kind": "",
       "kindModifiers": "",
       "textSpan": {
-        "start": 1098,
+        "start": 1094,
         "length": 6
       },
       "displayParts": [
diff --git a/tests/baselines/reference/jsDocTypeTag1.js b/tests/baselines/reference/jsDocTypeTag1.js
index 5dcabf2aa09..75333c69364 100644
--- a/tests/baselines/reference/jsDocTypeTag1.js
+++ b/tests/baselines/reference/jsDocTypeTag1.js
@@ -38,7 +38,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{String} "
+        }
+      ]
     }
   },
   {
@@ -80,7 +85,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Number} "
+        }
+      ]
     }
   },
   {
@@ -122,7 +132,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Boolean} "
+        }
+      ]
     }
   },
   {
@@ -164,7 +179,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Void} "
+        }
+      ]
     }
   },
   {
@@ -206,7 +226,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Undefined} "
+        }
+      ]
     }
   },
   {
@@ -248,7 +273,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Null} "
+        }
+      ]
     }
   },
   {
@@ -298,7 +328,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Array} "
+        }
+      ]
     }
   },
   {
@@ -352,7 +387,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Promise} "
+        }
+      ]
     }
   },
   {
@@ -394,7 +434,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Object} "
+        }
+      ]
     }
   },
   {
@@ -436,7 +481,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{Function} "
+        }
+      ]
     }
   },
   {
@@ -478,7 +528,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{*} "
+        }
+      ]
     }
   },
   {
@@ -520,7 +575,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{?} "
+        }
+      ]
     }
   },
   {
@@ -578,7 +638,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{String|Number} "
+        }
+      ]
     }
   }
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/jsDocTypeTag2.js b/tests/baselines/reference/jsDocTypeTag2.js
index d54b4557f06..01032a5cc09 100644
--- a/tests/baselines/reference/jsDocTypeTag2.js
+++ b/tests/baselines/reference/jsDocTypeTag2.js
@@ -38,7 +38,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{string} "
+        }
+      ]
     }
   },
   {
@@ -80,7 +85,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{number} "
+        }
+      ]
     }
   },
   {
@@ -122,7 +132,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{boolean} "
+        }
+      ]
     }
   },
   {
@@ -164,7 +179,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{void} "
+        }
+      ]
     }
   },
   {
@@ -206,7 +226,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{undefined} "
+        }
+      ]
     }
   },
   {
@@ -248,7 +273,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{null} "
+        }
+      ]
     }
   },
   {
@@ -298,7 +328,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{array} "
+        }
+      ]
     }
   },
   {
@@ -352,7 +387,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{promise} "
+        }
+      ]
     }
   },
   {
@@ -394,7 +434,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{?number} "
+        }
+      ]
     }
   },
   {
@@ -436,7 +481,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{function} "
+        }
+      ]
     }
   },
   {
@@ -514,7 +564,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{function (number): number} "
+        }
+      ]
     }
   },
   {
@@ -572,7 +627,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "type",
+          "text": "{string | number} "
+        }
+      ]
     }
   }
 ]
\ No newline at end of file
diff --git a/tests/baselines/reference/jsDocTypedef1.js b/tests/baselines/reference/jsDocTypedef1.js
index 28410ee8795..96a86a4f7a8 100644
--- a/tests/baselines/reference/jsDocTypedef1.js
+++ b/tests/baselines/reference/jsDocTypedef1.js
@@ -178,7 +178,12 @@
         }
       ],
       "documentation": [],
-      "tags": []
+      "tags": [
+        {
+          "name": "param",
+          "text": "opts "
+        }
+      ]
     }
   },
   {
diff --git a/tests/baselines/reference/jsxFactoryAndFragment.errors.txt b/tests/baselines/reference/jsxFactoryAndFragment.errors.txt
new file mode 100644
index 00000000000..d5dcffb152a
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndFragment.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/jsxFactoryAndFragment.tsx(3,1): error TS17016: JSX fragment is not supported when using --jsxFactory
+tests/cases/compiler/jsxFactoryAndFragment.tsx(4,1): error TS17016: JSX fragment is not supported when using --jsxFactory
+
+
+==== tests/cases/compiler/jsxFactoryAndFragment.tsx (2 errors) ====
+    declare var h: any;
+    
+    <></>;
+    ~~~~~
+!!! error TS17016: JSX fragment is not supported when using --jsxFactory
+    <><span>1</span><><span>2.1</span><span>2.2</span></></>;
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS17016: JSX fragment is not supported when using --jsxFactory
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxFactoryAndFragment.js b/tests/baselines/reference/jsxFactoryAndFragment.js
new file mode 100644
index 00000000000..3ed0517dce6
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndFragment.js
@@ -0,0 +1,13 @@
+//// [jsxFactoryAndFragment.tsx]
+declare var h: any;
+
+<></>;
+<><span>1</span><><span>2.1</span><span>2.2</span></></>;
+
+//// [jsxFactoryAndFragment.js]
+h(React.Fragment, null);
+h(React.Fragment, null,
+    h("span", null, "1"),
+    h(React.Fragment, null,
+        h("span", null, "2.1"),
+        h("span", null, "2.2")));
diff --git a/tests/baselines/reference/jsxFactoryAndFragment.symbols b/tests/baselines/reference/jsxFactoryAndFragment.symbols
new file mode 100644
index 00000000000..fdea7836626
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndFragment.symbols
@@ -0,0 +1,13 @@
+=== tests/cases/compiler/jsxFactoryAndFragment.tsx ===
+declare var h: any;
+>h : Symbol(h, Decl(jsxFactoryAndFragment.tsx, 0, 11))
+
+<></>;
+<><span>1</span><><span>2.1</span><span>2.2</span></></>;
+>span : Symbol(unknown)
+>span : Symbol(unknown)
+>span : Symbol(unknown)
+>span : Symbol(unknown)
+>span : Symbol(unknown)
+>span : Symbol(unknown)
+
diff --git a/tests/baselines/reference/jsxFactoryAndFragment.types b/tests/baselines/reference/jsxFactoryAndFragment.types
new file mode 100644
index 00000000000..ebbc0b6f5d0
--- /dev/null
+++ b/tests/baselines/reference/jsxFactoryAndFragment.types
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/jsxFactoryAndFragment.tsx ===
+declare var h: any;
+>h : any
+
+<></>;
+><></> : any
+
+<><span>1</span><><span>2.1</span><span>2.2</span></></>;
+><><span>1</span><><span>2.1</span><span>2.2</span></></> : any
+><span>1</span> : any
+>span : any
+>span : any
+><><span>2.1</span><span>2.2</span></> : any
+><span>2.1</span> : any
+>span : any
+>span : any
+><span>2.2</span> : any
+>span : any
+>span : any
+
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.types b/tests/baselines/reference/keyofAndIndexedAccess.types
index 9ae7b793ce2..302cefabf90 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.types
+++ b/tests/baselines/reference/keyofAndIndexedAccess.types
@@ -352,8 +352,8 @@ function f12(t: [Shape, boolean]) {
 >Shape : Shape
 
     let len = getProperty(t, "length");
->len : number
->getProperty(t, "length") : number
+>len : 2
+>getProperty(t, "length") : 2
 >getProperty : <T, K extends keyof T>(obj: T, key: K) => T[K]
 >t : [Shape, boolean]
 >"length" : "length"
diff --git a/tests/baselines/reference/literalsInComputedProperties1.js b/tests/baselines/reference/literalsInComputedProperties1.js
index c5b0060f626..4611925f2d4 100644
--- a/tests/baselines/reference/literalsInComputedProperties1.js
+++ b/tests/baselines/reference/literalsInComputedProperties1.js
@@ -89,4 +89,4 @@ var X;
 var a = X["foo"];
 var a0 = X["bar"];
 var _a;
-// TODO: make sure that enum still disallow template literals as member names 
+// TODO: make sure that enum still disallow template literals as member names
diff --git a/tests/baselines/reference/literalsInComputedProperties1.types b/tests/baselines/reference/literalsInComputedProperties1.types
index 188b088291e..d258e71d6fc 100644
--- a/tests/baselines/reference/literalsInComputedProperties1.types
+++ b/tests/baselines/reference/literalsInComputedProperties1.types
@@ -172,13 +172,13 @@ enum X {
 
 let a = X["foo"];
 >a : X
->X["foo"] : X."foo"
+>X["foo"] : X.foo
 >X : typeof X
 >"foo" : "foo"
 
 let a0 = X["bar"];
 >a0 : X
->X["bar"] : X.["bar"]
+>X["bar"] : X.bar
 >X : typeof X
 >"bar" : "bar"
 
diff --git a/tests/baselines/reference/logicalOrOperatorWithTypeParameters.types b/tests/baselines/reference/logicalOrOperatorWithTypeParameters.types
index ecd3fc52709..bc7bcbf4c2e 100644
--- a/tests/baselines/reference/logicalOrOperatorWithTypeParameters.types
+++ b/tests/baselines/reference/logicalOrOperatorWithTypeParameters.types
@@ -107,8 +107,8 @@ function fn3<T extends { a: string; b: string }, U extends { a: string; b: numbe
 >u : U
 
     var r3 = t || { a: '' };
->r3 : { a: string; }
->t || { a: '' } : { a: string; }
+>r3 : T | { a: string; }
+>t || { a: '' } : T | { a: string; }
 >t : T
 >{ a: '' } : { a: string; }
 >a : string
diff --git a/tests/baselines/reference/mappedTypeRelationships.errors.txt b/tests/baselines/reference/mappedTypeRelationships.errors.txt
index 1ea0c5a2612..2e51f73179d 100644
--- a/tests/baselines/reference/mappedTypeRelationships.errors.txt
+++ b/tests/baselines/reference/mappedTypeRelationships.errors.txt
@@ -460,4 +460,16 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
 !!! error TS2322:           Type 'T[string]' is not assignable to type 'U[string]'.
 !!! error TS2322:             Type 'T' is not assignable to type 'U'.
     }
+    
+    function f80<T>(t: T): Partial<T> {
+        return t;
+    }
+    
+    function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]> {
+        return t[k];
+    }
+    
+    function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]> {
+        return t[k1][k2];
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/mappedTypeRelationships.js b/tests/baselines/reference/mappedTypeRelationships.js
index 180c293b6c1..8bd44da5658 100644
--- a/tests/baselines/reference/mappedTypeRelationships.js
+++ b/tests/baselines/reference/mappedTypeRelationships.js
@@ -168,6 +168,18 @@ function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P i
     x = y;
     y = x;  // Error
 }
+
+function f80<T>(t: T): Partial<T> {
+    return t;
+}
+
+function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]> {
+    return t[k];
+}
+
+function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]> {
+    return t[k1][k2];
+}
 
 
 //// [mappedTypeRelationships.js]
@@ -289,6 +301,15 @@ function f76(x, y) {
     x = y;
     y = x; // Error
 }
+function f80(t) {
+    return t;
+}
+function f81(t, k) {
+    return t[k];
+}
+function f82(t, k1, k2) {
+    return t[k1][k2];
+}
 
 
 //// [mappedTypeRelationships.d.ts]
@@ -369,3 +390,6 @@ declare function f76<T, U extends T, K extends keyof T>(x: {
 }, y: {
     [P in K]: U[P];
 }): void;
+declare function f80<T>(t: T): Partial<T>;
+declare function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]>;
+declare function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]>;
diff --git a/tests/baselines/reference/mappedTypeRelationships.symbols b/tests/baselines/reference/mappedTypeRelationships.symbols
index c398d9955ad..ed5317e3d75 100644
--- a/tests/baselines/reference/mappedTypeRelationships.symbols
+++ b/tests/baselines/reference/mappedTypeRelationships.symbols
@@ -750,3 +750,58 @@ function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P i
 >x : Symbol(x, Decl(mappedTypeRelationships.ts, 165, 48))
 }
 
+function f80<T>(t: T): Partial<T> {
+>f80 : Symbol(f80, Decl(mappedTypeRelationships.ts, 168, 1))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 170, 13))
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 170, 16))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 170, 13))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 170, 13))
+
+    return t;
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 170, 16))
+}
+
+function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]> {
+>f81 : Symbol(f81, Decl(mappedTypeRelationships.ts, 172, 1))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 174, 13))
+>K : Symbol(K, Decl(mappedTypeRelationships.ts, 174, 15))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 174, 13))
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 174, 35))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 174, 13))
+>k : Symbol(k, Decl(mappedTypeRelationships.ts, 174, 40))
+>K : Symbol(K, Decl(mappedTypeRelationships.ts, 174, 15))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 174, 13))
+>K : Symbol(K, Decl(mappedTypeRelationships.ts, 174, 15))
+
+    return t[k];
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 174, 35))
+>k : Symbol(k, Decl(mappedTypeRelationships.ts, 174, 40))
+}
+
+function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]> {
+>f82 : Symbol(f82, Decl(mappedTypeRelationships.ts, 176, 1))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 178, 13))
+>K1 : Symbol(K1, Decl(mappedTypeRelationships.ts, 178, 15))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 178, 13))
+>K2 : Symbol(K2, Decl(mappedTypeRelationships.ts, 178, 35))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 178, 13))
+>K1 : Symbol(K1, Decl(mappedTypeRelationships.ts, 178, 15))
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 178, 60))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 178, 13))
+>k1 : Symbol(k1, Decl(mappedTypeRelationships.ts, 178, 65))
+>K1 : Symbol(K1, Decl(mappedTypeRelationships.ts, 178, 15))
+>k2 : Symbol(k2, Decl(mappedTypeRelationships.ts, 178, 73))
+>K2 : Symbol(K2, Decl(mappedTypeRelationships.ts, 178, 35))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships.ts, 178, 13))
+>K1 : Symbol(K1, Decl(mappedTypeRelationships.ts, 178, 15))
+>K2 : Symbol(K2, Decl(mappedTypeRelationships.ts, 178, 35))
+
+    return t[k1][k2];
+>t : Symbol(t, Decl(mappedTypeRelationships.ts, 178, 60))
+>k1 : Symbol(k1, Decl(mappedTypeRelationships.ts, 178, 65))
+>k2 : Symbol(k2, Decl(mappedTypeRelationships.ts, 178, 73))
+}
+
diff --git a/tests/baselines/reference/mappedTypeRelationships.types b/tests/baselines/reference/mappedTypeRelationships.types
index c698c6ba3c2..e1a00c9206b 100644
--- a/tests/baselines/reference/mappedTypeRelationships.types
+++ b/tests/baselines/reference/mappedTypeRelationships.types
@@ -856,3 +856,61 @@ function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P i
 >x : { [P in K]: T[P]; }
 }
 
+function f80<T>(t: T): Partial<T> {
+>f80 : <T>(t: T) => Partial<T>
+>T : T
+>t : T
+>T : T
+>Partial : Partial<T>
+>T : T
+
+    return t;
+>t : T
+}
+
+function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]> {
+>f81 : <T, K extends keyof T>(t: T, k: K) => Partial<T[K]>
+>T : T
+>K : K
+>T : T
+>t : T
+>T : T
+>k : K
+>K : K
+>Partial : Partial<T>
+>T : T
+>K : K
+
+    return t[k];
+>t[k] : T[K]
+>t : T
+>k : K
+}
+
+function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]> {
+>f82 : <T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2) => Partial<T[K1][K2]>
+>T : T
+>K1 : K1
+>T : T
+>K2 : K2
+>T : T
+>K1 : K1
+>t : T
+>T : T
+>k1 : K1
+>K1 : K1
+>k2 : K2
+>K2 : K2
+>Partial : Partial<T>
+>T : T
+>K1 : K1
+>K2 : K2
+
+    return t[k1][k2];
+>t[k1][k2] : T[K1][K2]
+>t[k1] : T[K1]
+>t : T
+>k1 : K1
+>k2 : K2
+}
+
diff --git a/tests/baselines/reference/mappedTypes5.errors.txt b/tests/baselines/reference/mappedTypes5.errors.txt
new file mode 100644
index 00000000000..d0c32cd1dd9
--- /dev/null
+++ b/tests/baselines/reference/mappedTypes5.errors.txt
@@ -0,0 +1,73 @@
+tests/cases/conformance/types/mapped/mappedTypes5.ts(6,9): error TS2322: Type 'Partial<T>' is not assignable to type 'Readonly<T>'.
+tests/cases/conformance/types/mapped/mappedTypes5.ts(8,9): error TS2322: Type 'Partial<Readonly<T>>' is not assignable to type 'Readonly<T>'.
+tests/cases/conformance/types/mapped/mappedTypes5.ts(9,9): error TS2322: Type 'Readonly<Partial<T>>' is not assignable to type 'Readonly<T>'.
+
+
+==== tests/cases/conformance/types/mapped/mappedTypes5.ts (3 errors) ====
+    function f<T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) {
+        let a1: Partial<T> = p;
+        let a2: Partial<T> = r;
+        let a3: Partial<T> = pr;
+        let a4: Partial<T> = rp;
+        let b1: Readonly<T> = p;  // Error
+            ~~
+!!! error TS2322: Type 'Partial<T>' is not assignable to type 'Readonly<T>'.
+        let b2: Readonly<T> = r;
+        let b3: Readonly<T> = pr;  // Error
+            ~~
+!!! error TS2322: Type 'Partial<Readonly<T>>' is not assignable to type 'Readonly<T>'.
+        let b4: Readonly<T> = rp;  // Error
+            ~~
+!!! error TS2322: Type 'Readonly<Partial<T>>' is not assignable to type 'Readonly<T>'.
+        let c1: Partial<Readonly<T>> = p;
+        let c2: Partial<Readonly<T>> = r;
+        let c3: Partial<Readonly<T>> = pr;
+        let c4: Partial<Readonly<T>> = rp;
+        let d1: Readonly<Partial<T>> = p;
+        let d2: Readonly<Partial<T>> = r;
+        let d3: Readonly<Partial<T>> = pr;
+        let d4: Readonly<Partial<T>> = rp;
+    }
+    
+    // Repro from #17682
+    
+    type State = {
+        [key: string]: string | boolean | number | null;
+    };
+    
+    type Args1<T extends State> = {
+        readonly previous: Readonly<Partial<T>>;
+        readonly current: Readonly<Partial<T>>;
+    };
+    
+    type Args2<T extends State> = {
+        readonly previous: Partial<Readonly<T>>;
+        readonly current: Partial<Readonly<T>>;
+    };
+    
+    function doit<T extends State>() {
+        let previous: Partial<T> = Object.create(null);
+        let current: Partial<T> = Object.create(null);
+        let args1: Args1<T> = { previous, current };
+        let args2: Args2<T> = { previous, current };
+    }
+    
+    type State2 = { foo: number, bar: string };
+    
+    type Args3 = {
+        readonly previous: Readonly<Partial<State2>>;
+        readonly current: Readonly<Partial<State2>>;
+    };
+    
+    type Args4 = {
+        readonly previous: Partial<Readonly<State2>>;
+        readonly current: Partial<Readonly<State2>>;
+    };
+    
+    function doit2() {
+        let previous: Partial<State2> = Object.create(null);
+        let current: Partial<State2> = Object.create(null);
+        let args1: Args3 = { previous, current };
+        let args2: Args4 = { previous, current };
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/mappedTypes5.js b/tests/baselines/reference/mappedTypes5.js
new file mode 100644
index 00000000000..6f20b71ed7b
--- /dev/null
+++ b/tests/baselines/reference/mappedTypes5.js
@@ -0,0 +1,95 @@
+//// [mappedTypes5.ts]
+function f<T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) {
+    let a1: Partial<T> = p;
+    let a2: Partial<T> = r;
+    let a3: Partial<T> = pr;
+    let a4: Partial<T> = rp;
+    let b1: Readonly<T> = p;  // Error
+    let b2: Readonly<T> = r;
+    let b3: Readonly<T> = pr;  // Error
+    let b4: Readonly<T> = rp;  // Error
+    let c1: Partial<Readonly<T>> = p;
+    let c2: Partial<Readonly<T>> = r;
+    let c3: Partial<Readonly<T>> = pr;
+    let c4: Partial<Readonly<T>> = rp;
+    let d1: Readonly<Partial<T>> = p;
+    let d2: Readonly<Partial<T>> = r;
+    let d3: Readonly<Partial<T>> = pr;
+    let d4: Readonly<Partial<T>> = rp;
+}
+
+// Repro from #17682
+
+type State = {
+    [key: string]: string | boolean | number | null;
+};
+
+type Args1<T extends State> = {
+    readonly previous: Readonly<Partial<T>>;
+    readonly current: Readonly<Partial<T>>;
+};
+
+type Args2<T extends State> = {
+    readonly previous: Partial<Readonly<T>>;
+    readonly current: Partial<Readonly<T>>;
+};
+
+function doit<T extends State>() {
+    let previous: Partial<T> = Object.create(null);
+    let current: Partial<T> = Object.create(null);
+    let args1: Args1<T> = { previous, current };
+    let args2: Args2<T> = { previous, current };
+}
+
+type State2 = { foo: number, bar: string };
+
+type Args3 = {
+    readonly previous: Readonly<Partial<State2>>;
+    readonly current: Readonly<Partial<State2>>;
+};
+
+type Args4 = {
+    readonly previous: Partial<Readonly<State2>>;
+    readonly current: Partial<Readonly<State2>>;
+};
+
+function doit2() {
+    let previous: Partial<State2> = Object.create(null);
+    let current: Partial<State2> = Object.create(null);
+    let args1: Args3 = { previous, current };
+    let args2: Args4 = { previous, current };
+}
+
+
+//// [mappedTypes5.js]
+"use strict";
+function f(p, r, pr, rp) {
+    var a1 = p;
+    var a2 = r;
+    var a3 = pr;
+    var a4 = rp;
+    var b1 = p; // Error
+    var b2 = r;
+    var b3 = pr; // Error
+    var b4 = rp; // Error
+    var c1 = p;
+    var c2 = r;
+    var c3 = pr;
+    var c4 = rp;
+    var d1 = p;
+    var d2 = r;
+    var d3 = pr;
+    var d4 = rp;
+}
+function doit() {
+    var previous = Object.create(null);
+    var current = Object.create(null);
+    var args1 = { previous: previous, current: current };
+    var args2 = { previous: previous, current: current };
+}
+function doit2() {
+    var previous = Object.create(null);
+    var current = Object.create(null);
+    var args1 = { previous: previous, current: current };
+    var args2 = { previous: previous, current: current };
+}
diff --git a/tests/baselines/reference/mappedTypes5.symbols b/tests/baselines/reference/mappedTypes5.symbols
new file mode 100644
index 00000000000..7a499c4c4e9
--- /dev/null
+++ b/tests/baselines/reference/mappedTypes5.symbols
@@ -0,0 +1,279 @@
+=== tests/cases/conformance/types/mapped/mappedTypes5.ts ===
+function f<T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) {
+>f : Symbol(f, Decl(mappedTypes5.ts, 0, 0))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>p : Symbol(p, Decl(mappedTypes5.ts, 0, 14))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>r : Symbol(r, Decl(mappedTypes5.ts, 0, 28))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>pr : Symbol(pr, Decl(mappedTypes5.ts, 0, 44))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>rp : Symbol(rp, Decl(mappedTypes5.ts, 0, 70))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+
+    let a1: Partial<T> = p;
+>a1 : Symbol(a1, Decl(mappedTypes5.ts, 1, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>p : Symbol(p, Decl(mappedTypes5.ts, 0, 14))
+
+    let a2: Partial<T> = r;
+>a2 : Symbol(a2, Decl(mappedTypes5.ts, 2, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>r : Symbol(r, Decl(mappedTypes5.ts, 0, 28))
+
+    let a3: Partial<T> = pr;
+>a3 : Symbol(a3, Decl(mappedTypes5.ts, 3, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>pr : Symbol(pr, Decl(mappedTypes5.ts, 0, 44))
+
+    let a4: Partial<T> = rp;
+>a4 : Symbol(a4, Decl(mappedTypes5.ts, 4, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>rp : Symbol(rp, Decl(mappedTypes5.ts, 0, 70))
+
+    let b1: Readonly<T> = p;  // Error
+>b1 : Symbol(b1, Decl(mappedTypes5.ts, 5, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>p : Symbol(p, Decl(mappedTypes5.ts, 0, 14))
+
+    let b2: Readonly<T> = r;
+>b2 : Symbol(b2, Decl(mappedTypes5.ts, 6, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>r : Symbol(r, Decl(mappedTypes5.ts, 0, 28))
+
+    let b3: Readonly<T> = pr;  // Error
+>b3 : Symbol(b3, Decl(mappedTypes5.ts, 7, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>pr : Symbol(pr, Decl(mappedTypes5.ts, 0, 44))
+
+    let b4: Readonly<T> = rp;  // Error
+>b4 : Symbol(b4, Decl(mappedTypes5.ts, 8, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>rp : Symbol(rp, Decl(mappedTypes5.ts, 0, 70))
+
+    let c1: Partial<Readonly<T>> = p;
+>c1 : Symbol(c1, Decl(mappedTypes5.ts, 9, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>p : Symbol(p, Decl(mappedTypes5.ts, 0, 14))
+
+    let c2: Partial<Readonly<T>> = r;
+>c2 : Symbol(c2, Decl(mappedTypes5.ts, 10, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>r : Symbol(r, Decl(mappedTypes5.ts, 0, 28))
+
+    let c3: Partial<Readonly<T>> = pr;
+>c3 : Symbol(c3, Decl(mappedTypes5.ts, 11, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>pr : Symbol(pr, Decl(mappedTypes5.ts, 0, 44))
+
+    let c4: Partial<Readonly<T>> = rp;
+>c4 : Symbol(c4, Decl(mappedTypes5.ts, 12, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>rp : Symbol(rp, Decl(mappedTypes5.ts, 0, 70))
+
+    let d1: Readonly<Partial<T>> = p;
+>d1 : Symbol(d1, Decl(mappedTypes5.ts, 13, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>p : Symbol(p, Decl(mappedTypes5.ts, 0, 14))
+
+    let d2: Readonly<Partial<T>> = r;
+>d2 : Symbol(d2, Decl(mappedTypes5.ts, 14, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>r : Symbol(r, Decl(mappedTypes5.ts, 0, 28))
+
+    let d3: Readonly<Partial<T>> = pr;
+>d3 : Symbol(d3, Decl(mappedTypes5.ts, 15, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>pr : Symbol(pr, Decl(mappedTypes5.ts, 0, 44))
+
+    let d4: Readonly<Partial<T>> = rp;
+>d4 : Symbol(d4, Decl(mappedTypes5.ts, 16, 7))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 0, 11))
+>rp : Symbol(rp, Decl(mappedTypes5.ts, 0, 70))
+}
+
+// Repro from #17682
+
+type State = {
+>State : Symbol(State, Decl(mappedTypes5.ts, 17, 1))
+
+    [key: string]: string | boolean | number | null;
+>key : Symbol(key, Decl(mappedTypes5.ts, 22, 5))
+
+};
+
+type Args1<T extends State> = {
+>Args1 : Symbol(Args1, Decl(mappedTypes5.ts, 23, 2))
+>T : Symbol(T, Decl(mappedTypes5.ts, 25, 11))
+>State : Symbol(State, Decl(mappedTypes5.ts, 17, 1))
+
+    readonly previous: Readonly<Partial<T>>;
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 25, 31))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 25, 11))
+
+    readonly current: Readonly<Partial<T>>;
+>current : Symbol(current, Decl(mappedTypes5.ts, 26, 44))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 25, 11))
+
+};
+
+type Args2<T extends State> = {
+>Args2 : Symbol(Args2, Decl(mappedTypes5.ts, 28, 2))
+>T : Symbol(T, Decl(mappedTypes5.ts, 30, 11))
+>State : Symbol(State, Decl(mappedTypes5.ts, 17, 1))
+
+    readonly previous: Partial<Readonly<T>>;
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 30, 31))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 30, 11))
+
+    readonly current: Partial<Readonly<T>>;
+>current : Symbol(current, Decl(mappedTypes5.ts, 31, 44))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 30, 11))
+
+};
+
+function doit<T extends State>() {
+>doit : Symbol(doit, Decl(mappedTypes5.ts, 33, 2))
+>T : Symbol(T, Decl(mappedTypes5.ts, 35, 14))
+>State : Symbol(State, Decl(mappedTypes5.ts, 17, 1))
+
+    let previous: Partial<T> = Object.create(null);
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 36, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 35, 14))
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+    let current: Partial<T> = Object.create(null);
+>current : Symbol(current, Decl(mappedTypes5.ts, 37, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypes5.ts, 35, 14))
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+    let args1: Args1<T> = { previous, current };
+>args1 : Symbol(args1, Decl(mappedTypes5.ts, 38, 7))
+>Args1 : Symbol(Args1, Decl(mappedTypes5.ts, 23, 2))
+>T : Symbol(T, Decl(mappedTypes5.ts, 35, 14))
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 38, 27))
+>current : Symbol(current, Decl(mappedTypes5.ts, 38, 37))
+
+    let args2: Args2<T> = { previous, current };
+>args2 : Symbol(args2, Decl(mappedTypes5.ts, 39, 7))
+>Args2 : Symbol(Args2, Decl(mappedTypes5.ts, 28, 2))
+>T : Symbol(T, Decl(mappedTypes5.ts, 35, 14))
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 39, 27))
+>current : Symbol(current, Decl(mappedTypes5.ts, 39, 37))
+}
+
+type State2 = { foo: number, bar: string };
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+>foo : Symbol(foo, Decl(mappedTypes5.ts, 42, 15))
+>bar : Symbol(bar, Decl(mappedTypes5.ts, 42, 28))
+
+type Args3 = {
+>Args3 : Symbol(Args3, Decl(mappedTypes5.ts, 42, 43))
+
+    readonly previous: Readonly<Partial<State2>>;
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 44, 14))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+
+    readonly current: Readonly<Partial<State2>>;
+>current : Symbol(current, Decl(mappedTypes5.ts, 45, 49))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+
+};
+
+type Args4 = {
+>Args4 : Symbol(Args4, Decl(mappedTypes5.ts, 47, 2))
+
+    readonly previous: Partial<Readonly<State2>>;
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 49, 14))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+
+    readonly current: Partial<Readonly<State2>>;
+>current : Symbol(current, Decl(mappedTypes5.ts, 50, 49))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>Readonly : Symbol(Readonly, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+
+};
+
+function doit2() {
+>doit2 : Symbol(doit2, Decl(mappedTypes5.ts, 52, 2))
+
+    let previous: Partial<State2> = Object.create(null);
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 55, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+    let current: Partial<State2> = Object.create(null);
+>current : Symbol(current, Decl(mappedTypes5.ts, 56, 7))
+>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
+>State2 : Symbol(State2, Decl(mappedTypes5.ts, 40, 1))
+>Object.create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>create : Symbol(ObjectConstructor.create, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+    let args1: Args3 = { previous, current };
+>args1 : Symbol(args1, Decl(mappedTypes5.ts, 57, 7))
+>Args3 : Symbol(Args3, Decl(mappedTypes5.ts, 42, 43))
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 57, 24))
+>current : Symbol(current, Decl(mappedTypes5.ts, 57, 34))
+
+    let args2: Args4 = { previous, current };
+>args2 : Symbol(args2, Decl(mappedTypes5.ts, 58, 7))
+>Args4 : Symbol(Args4, Decl(mappedTypes5.ts, 47, 2))
+>previous : Symbol(previous, Decl(mappedTypes5.ts, 58, 24))
+>current : Symbol(current, Decl(mappedTypes5.ts, 58, 34))
+}
+
diff --git a/tests/baselines/reference/mappedTypes5.types b/tests/baselines/reference/mappedTypes5.types
new file mode 100644
index 00000000000..2cbc66523e2
--- /dev/null
+++ b/tests/baselines/reference/mappedTypes5.types
@@ -0,0 +1,292 @@
+=== tests/cases/conformance/types/mapped/mappedTypes5.ts ===
+function f<T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) {
+>f : <T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) => void
+>T : T
+>p : Partial<T>
+>Partial : Partial<T>
+>T : T
+>r : Readonly<T>
+>Readonly : Readonly<T>
+>T : T
+>pr : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+>rp : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+
+    let a1: Partial<T> = p;
+>a1 : Partial<T>
+>Partial : Partial<T>
+>T : T
+>p : Partial<T>
+
+    let a2: Partial<T> = r;
+>a2 : Partial<T>
+>Partial : Partial<T>
+>T : T
+>r : Readonly<T>
+
+    let a3: Partial<T> = pr;
+>a3 : Partial<T>
+>Partial : Partial<T>
+>T : T
+>pr : Partial<Readonly<T>>
+
+    let a4: Partial<T> = rp;
+>a4 : Partial<T>
+>Partial : Partial<T>
+>T : T
+>rp : Readonly<Partial<T>>
+
+    let b1: Readonly<T> = p;  // Error
+>b1 : Readonly<T>
+>Readonly : Readonly<T>
+>T : T
+>p : Partial<T>
+
+    let b2: Readonly<T> = r;
+>b2 : Readonly<T>
+>Readonly : Readonly<T>
+>T : T
+>r : Readonly<T>
+
+    let b3: Readonly<T> = pr;  // Error
+>b3 : Readonly<T>
+>Readonly : Readonly<T>
+>T : T
+>pr : Partial<Readonly<T>>
+
+    let b4: Readonly<T> = rp;  // Error
+>b4 : Readonly<T>
+>Readonly : Readonly<T>
+>T : T
+>rp : Readonly<Partial<T>>
+
+    let c1: Partial<Readonly<T>> = p;
+>c1 : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+>p : Partial<T>
+
+    let c2: Partial<Readonly<T>> = r;
+>c2 : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+>r : Readonly<T>
+
+    let c3: Partial<Readonly<T>> = pr;
+>c3 : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+>pr : Partial<Readonly<T>>
+
+    let c4: Partial<Readonly<T>> = rp;
+>c4 : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+>rp : Readonly<Partial<T>>
+
+    let d1: Readonly<Partial<T>> = p;
+>d1 : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+>p : Partial<T>
+
+    let d2: Readonly<Partial<T>> = r;
+>d2 : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+>r : Readonly<T>
+
+    let d3: Readonly<Partial<T>> = pr;
+>d3 : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+>pr : Partial<Readonly<T>>
+
+    let d4: Readonly<Partial<T>> = rp;
+>d4 : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+>rp : Readonly<Partial<T>>
+}
+
+// Repro from #17682
+
+type State = {
+>State : State
+
+    [key: string]: string | boolean | number | null;
+>key : string
+>null : null
+
+};
+
+type Args1<T extends State> = {
+>Args1 : Args1<T>
+>T : T
+>State : State
+
+    readonly previous: Readonly<Partial<T>>;
+>previous : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+
+    readonly current: Readonly<Partial<T>>;
+>current : Readonly<Partial<T>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>T : T
+
+};
+
+type Args2<T extends State> = {
+>Args2 : Args2<T>
+>T : T
+>State : State
+
+    readonly previous: Partial<Readonly<T>>;
+>previous : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+
+    readonly current: Partial<Readonly<T>>;
+>current : Partial<Readonly<T>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>T : T
+
+};
+
+function doit<T extends State>() {
+>doit : <T extends State>() => void
+>T : T
+>State : State
+
+    let previous: Partial<T> = Object.create(null);
+>previous : Partial<T>
+>Partial : Partial<T>
+>T : T
+>Object.create(null) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>null : null
+
+    let current: Partial<T> = Object.create(null);
+>current : Partial<T>
+>Partial : Partial<T>
+>T : T
+>Object.create(null) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>null : null
+
+    let args1: Args1<T> = { previous, current };
+>args1 : Args1<T>
+>Args1 : Args1<T>
+>T : T
+>{ previous, current } : { previous: Partial<T>; current: Partial<T>; }
+>previous : Partial<T>
+>current : Partial<T>
+
+    let args2: Args2<T> = { previous, current };
+>args2 : Args2<T>
+>Args2 : Args2<T>
+>T : T
+>{ previous, current } : { previous: Partial<T>; current: Partial<T>; }
+>previous : Partial<T>
+>current : Partial<T>
+}
+
+type State2 = { foo: number, bar: string };
+>State2 : State2
+>foo : number
+>bar : string
+
+type Args3 = {
+>Args3 : Args3
+
+    readonly previous: Readonly<Partial<State2>>;
+>previous : Readonly<Partial<State2>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>State2 : State2
+
+    readonly current: Readonly<Partial<State2>>;
+>current : Readonly<Partial<State2>>
+>Readonly : Readonly<T>
+>Partial : Partial<T>
+>State2 : State2
+
+};
+
+type Args4 = {
+>Args4 : Args4
+
+    readonly previous: Partial<Readonly<State2>>;
+>previous : Partial<Readonly<State2>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>State2 : State2
+
+    readonly current: Partial<Readonly<State2>>;
+>current : Partial<Readonly<State2>>
+>Partial : Partial<T>
+>Readonly : Readonly<T>
+>State2 : State2
+
+};
+
+function doit2() {
+>doit2 : () => void
+
+    let previous: Partial<State2> = Object.create(null);
+>previous : Partial<State2>
+>Partial : Partial<T>
+>State2 : State2
+>Object.create(null) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>null : null
+
+    let current: Partial<State2> = Object.create(null);
+>current : Partial<State2>
+>Partial : Partial<T>
+>State2 : State2
+>Object.create(null) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>Object : ObjectConstructor
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap & ThisType<any>): any; }
+>null : null
+
+    let args1: Args3 = { previous, current };
+>args1 : Args3
+>Args3 : Args3
+>{ previous, current } : { previous: Partial<State2>; current: Partial<State2>; }
+>previous : Partial<State2>
+>current : Partial<State2>
+
+    let args2: Args4 = { previous, current };
+>args2 : Args4
+>Args4 : Args4
+>{ previous, current } : { previous: Partial<State2>; current: Partial<State2>; }
+>previous : Partial<State2>
+>current : Partial<State2>
+}
+
diff --git a/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.symbols b/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.symbols
index 917c5bbc654..4c51c416f3c 100644
--- a/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.symbols
+++ b/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.symbols
@@ -6,9 +6,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.ts, 0, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.types b/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.types
index 73dad44343b..1f8f0c5cb63 100644
--- a/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.types
+++ b/tests/baselines/reference/modularizeLibrary_ErrorFromUsingWellknownSymbolWithOutES6WellknownSymbolLib.types
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>Array.from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.symbols b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.symbols
index 6842ec9ae25..1f55a3890ff 100644
--- a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.symbols
+++ b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.symbols
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_NoErrorDuplicateLibOptions1.ts, 1, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.types b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.types
index 4743391fcf1..afc286ca708 100644
--- a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.types
+++ b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions1.types
@@ -8,9 +8,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.symbols b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.symbols
index d9af41e6027..d6eb97d3673 100644
--- a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.symbols
+++ b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.symbols
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_NoErrorDuplicateLibOptions2.ts, 1, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.types b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.types
index a700c1c03f6..d394c411c4d 100644
--- a/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.types
+++ b/tests/baselines/reference/modularizeLibrary_NoErrorDuplicateLibOptions2.types
@@ -8,9 +8,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.symbols b/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.symbols
index 2ae943ab81d..08e90ead0ea 100644
--- a/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.symbols
+++ b/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.symbols
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_TargetES5UsingES6Lib.ts, 1, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.types b/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.types
index d51e87c8b9d..479747d3e0e 100644
--- a/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.types
+++ b/tests/baselines/reference/modularizeLibrary_TargetES5UsingES6Lib.types
@@ -8,9 +8,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.symbols b/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.symbols
index 182daeefd1a..1d3f903f880 100644
--- a/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.symbols
+++ b/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.symbols
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_TargetES6UsingES6Lib.ts, 1, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.types b/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.types
index 8296220b36e..efb2beddb4f 100644
--- a/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.types
+++ b/tests/baselines/reference/modularizeLibrary_TargetES6UsingES6Lib.types
@@ -8,9 +8,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>Array.from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : { <T, U = T>(iterable: Iterable<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any): U[]; }
+>from : { <T>(iterable: Iterable<T>): T[]; <T, U>(iterable: Iterable<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.symbols b/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.symbols
index a9f94d2e1ca..489d23c4d48 100644
--- a/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.symbols
+++ b/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.symbols
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_UsingES5LibAndES6ArrayLib.ts, 1, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.types b/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.types
index 7a3d1a8c7c3..d624c1ac259 100644
--- a/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.types
+++ b/tests/baselines/reference/modularizeLibrary_UsingES5LibAndES6ArrayLib.types
@@ -8,9 +8,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>Array.from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.symbols b/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.symbols
index 7870c6362d3..b00d1aba743 100644
--- a/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.symbols
+++ b/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.symbols
@@ -6,9 +6,9 @@ function f(x: number, y: number, z: number) {
 >z : Symbol(z, Decl(modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.ts, 0, 32))
 
     return Array.from(arguments);
->Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>Array.from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >Array : Symbol(Array, Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
->from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --))
+>from : Symbol(ArrayConstructor.from, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 >arguments : Symbol(arguments)
 }
 
diff --git a/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.types b/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.types
index 1012cbad340..caca4cf8759 100644
--- a/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.types
+++ b/tests/baselines/reference/modularizeLibrary_UsingES5LibES6ArrayLibES6WellknownSymbolLib.types
@@ -7,9 +7,9 @@ function f(x: number, y: number, z: number) {
 
     return Array.from(arguments);
 >Array.from(arguments) : any[]
->Array.from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>Array.from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >Array : ArrayConstructor
->from : <T, U = T>(arrayLike: ArrayLike<T>, mapfn?: (v: T, k: number) => U, thisArg?: any) => U[]
+>from : { <T>(arrayLike: ArrayLike<T>): T[]; <T, U>(arrayLike: ArrayLike<T>, mapfn: (v: T, k: number) => U, thisArg?: any): U[]; }
 >arguments : IArguments
 }
 
diff --git a/tests/baselines/reference/moduleAssignmentCompat1.errors.txt b/tests/baselines/reference/moduleAssignmentCompat1.errors.txt
index 5b4fe8d3c7c..740c42b0e1c 100644
--- a/tests/baselines/reference/moduleAssignmentCompat1.errors.txt
+++ b/tests/baselines/reference/moduleAssignmentCompat1.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/moduleAssignmentCompat1.ts(9,8): error TS2304: Cannot find name 'A'.
-tests/cases/compiler/moduleAssignmentCompat1.ts(10,8): error TS2304: Cannot find name 'B'.
+tests/cases/compiler/moduleAssignmentCompat1.ts(9,8): error TS2709: Cannot use namespace 'A' as a type.
+tests/cases/compiler/moduleAssignmentCompat1.ts(10,8): error TS2709: Cannot use namespace 'B' as a type.
 
 
 ==== tests/cases/compiler/moduleAssignmentCompat1.ts (2 errors) ====
@@ -13,10 +13,10 @@ tests/cases/compiler/moduleAssignmentCompat1.ts(10,8): error TS2304: Cannot find
     
     var a: A;
            ~
-!!! error TS2304: Cannot find name 'A'.
+!!! error TS2709: Cannot use namespace 'A' as a type.
     var b: B;
            ~
-!!! error TS2304: Cannot find name 'B'.
+!!! error TS2709: Cannot use namespace 'B' as a type.
     
     // no error
     a = b;
diff --git a/tests/baselines/reference/moduleAssignmentCompat2.errors.txt b/tests/baselines/reference/moduleAssignmentCompat2.errors.txt
index 5a14ff03ead..a9ec70739b9 100644
--- a/tests/baselines/reference/moduleAssignmentCompat2.errors.txt
+++ b/tests/baselines/reference/moduleAssignmentCompat2.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/moduleAssignmentCompat2.ts(9,8): error TS2304: Cannot find name 'A'.
-tests/cases/compiler/moduleAssignmentCompat2.ts(10,8): error TS2304: Cannot find name 'B'.
+tests/cases/compiler/moduleAssignmentCompat2.ts(9,8): error TS2709: Cannot use namespace 'A' as a type.
+tests/cases/compiler/moduleAssignmentCompat2.ts(10,8): error TS2709: Cannot use namespace 'B' as a type.
 
 
 ==== tests/cases/compiler/moduleAssignmentCompat2.ts (2 errors) ====
@@ -13,10 +13,10 @@ tests/cases/compiler/moduleAssignmentCompat2.ts(10,8): error TS2304: Cannot find
     
     var a: A;
            ~
-!!! error TS2304: Cannot find name 'A'.
+!!! error TS2709: Cannot use namespace 'A' as a type.
     var b: B;
            ~
-!!! error TS2304: Cannot find name 'B'.
+!!! error TS2709: Cannot use namespace 'B' as a type.
     
     a = b;
     b = a; // error
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleAssignmentCompat3.errors.txt b/tests/baselines/reference/moduleAssignmentCompat3.errors.txt
index 656fad20a7e..1afc823757c 100644
--- a/tests/baselines/reference/moduleAssignmentCompat3.errors.txt
+++ b/tests/baselines/reference/moduleAssignmentCompat3.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/moduleAssignmentCompat3.ts(8,8): error TS2304: Cannot find name 'A'.
-tests/cases/compiler/moduleAssignmentCompat3.ts(9,8): error TS2304: Cannot find name 'B'.
+tests/cases/compiler/moduleAssignmentCompat3.ts(8,8): error TS2709: Cannot use namespace 'A' as a type.
+tests/cases/compiler/moduleAssignmentCompat3.ts(9,8): error TS2709: Cannot use namespace 'B' as a type.
 
 
 ==== tests/cases/compiler/moduleAssignmentCompat3.ts (2 errors) ====
@@ -12,10 +12,10 @@ tests/cases/compiler/moduleAssignmentCompat3.ts(9,8): error TS2304: Cannot find
     
     var a: A;
            ~
-!!! error TS2304: Cannot find name 'A'.
+!!! error TS2709: Cannot use namespace 'A' as a type.
     var b: B;
            ~
-!!! error TS2304: Cannot find name 'B'.
+!!! error TS2709: Cannot use namespace 'B' as a type.
     
     // both errors
     a = b;
diff --git a/tests/baselines/reference/moduleAssignmentCompat4.errors.txt b/tests/baselines/reference/moduleAssignmentCompat4.errors.txt
index 7d6204b53e1..370428d1087 100644
--- a/tests/baselines/reference/moduleAssignmentCompat4.errors.txt
+++ b/tests/baselines/reference/moduleAssignmentCompat4.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/moduleAssignmentCompat4.ts(12,8): error TS2304: Cannot find name 'A'.
-tests/cases/compiler/moduleAssignmentCompat4.ts(13,8): error TS2304: Cannot find name 'B'.
+tests/cases/compiler/moduleAssignmentCompat4.ts(12,8): error TS2709: Cannot use namespace 'A' as a type.
+tests/cases/compiler/moduleAssignmentCompat4.ts(13,8): error TS2709: Cannot use namespace 'B' as a type.
 
 
 ==== tests/cases/compiler/moduleAssignmentCompat4.ts (2 errors) ====
@@ -16,10 +16,10 @@ tests/cases/compiler/moduleAssignmentCompat4.ts(13,8): error TS2304: Cannot find
     
     var a: A;
            ~
-!!! error TS2304: Cannot find name 'A'.
+!!! error TS2709: Cannot use namespace 'A' as a type.
     var b: B;
            ~
-!!! error TS2304: Cannot find name 'B'.
+!!! error TS2709: Cannot use namespace 'B' as a type.
     
     a = b;
     b = a; // error
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleCrashBug1.errors.txt b/tests/baselines/reference/moduleCrashBug1.errors.txt
index e50e2a1c3e6..1c187056ff6 100644
--- a/tests/baselines/reference/moduleCrashBug1.errors.txt
+++ b/tests/baselines/reference/moduleCrashBug1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/moduleCrashBug1.ts(18,9): error TS2304: Cannot find name '_modes'.
+tests/cases/compiler/moduleCrashBug1.ts(18,9): error TS2709: Cannot use namespace '_modes' as a type.
 
 
 ==== tests/cases/compiler/moduleCrashBug1.ts (1 errors) ====
@@ -21,7 +21,7 @@ tests/cases/compiler/moduleCrashBug1.ts(18,9): error TS2304: Cannot find name '_
     
     var m : _modes;
             ~~~~~~
-!!! error TS2304: Cannot find name '_modes'.
+!!! error TS2709: Cannot use namespace '_modes' as a type.
     
     
     
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleIdentifiers.js b/tests/baselines/reference/moduleIdentifiers.js
index 04d39019482..d3a654b8670 100644
--- a/tests/baselines/reference/moduleIdentifiers.js
+++ b/tests/baselines/reference/moduleIdentifiers.js
@@ -19,4 +19,4 @@ var M;
 //var m: M = M;
 var x1 = M.a;
 //var x2 = m.a;
-//var q: m.P; 
+//var q: m.P;
diff --git a/tests/baselines/reference/moduleInTypePosition1.errors.txt b/tests/baselines/reference/moduleInTypePosition1.errors.txt
index ff5fa2da4eb..46599641772 100644
--- a/tests/baselines/reference/moduleInTypePosition1.errors.txt
+++ b/tests/baselines/reference/moduleInTypePosition1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/moduleInTypePosition1_1.ts(3,14): error TS2304: Cannot find name 'WinJS'.
+tests/cases/compiler/moduleInTypePosition1_1.ts(3,14): error TS2709: Cannot use namespace 'WinJS' as a type.
 
 
 ==== tests/cases/compiler/moduleInTypePosition1_1.ts (1 errors) ====
@@ -6,7 +6,7 @@ tests/cases/compiler/moduleInTypePosition1_1.ts(3,14): error TS2304: Cannot find
     import WinJS = require('./moduleInTypePosition1_0');
     var x = (w1: WinJS) => { };
                  ~~~~~
-!!! error TS2304: Cannot find name 'WinJS'.
+!!! error TS2709: Cannot use namespace 'WinJS' as a type.
     
 ==== tests/cases/compiler/moduleInTypePosition1_0.ts (0 errors) ====
     export class Promise {
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions.js b/tests/baselines/reference/moduleResolutionWithExtensions.js
index c1e0310e995..3406bb0adae 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions.js
+++ b/tests/baselines/reference/moduleResolutionWithExtensions.js
@@ -28,11 +28,11 @@ import j from "./jquery.js"
 "use strict";
 exports.__esModule = true;
 exports["default"] = 0;
-// No extension: '.ts' added 
+// No extension: '.ts' added
 //// [b.js]
 "use strict";
 exports.__esModule = true;
-// '.js' extension: stripped and replaced with '.ts' 
+// '.js' extension: stripped and replaced with '.ts'
 //// [d.js]
 "use strict";
 exports.__esModule = true;
diff --git a/tests/baselines/reference/moduleVisibilityTest3.errors.txt b/tests/baselines/reference/moduleVisibilityTest3.errors.txt
index dfecadec23e..d901d48c5a8 100644
--- a/tests/baselines/reference/moduleVisibilityTest3.errors.txt
+++ b/tests/baselines/reference/moduleVisibilityTest3.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/moduleVisibilityTest3.ts(20,22): error TS2304: Cannot find name 'modes'.
+tests/cases/compiler/moduleVisibilityTest3.ts(20,22): error TS2709: Cannot use namespace 'modes' as a type.
 tests/cases/compiler/moduleVisibilityTest3.ts(20,39): error TS2694: Namespace '_modes' has no exported member 'Mode'.
 tests/cases/compiler/moduleVisibilityTest3.ts(21,22): error TS2694: Namespace '_modes' has no exported member 'Mode'.
 
@@ -25,7 +25,7 @@ tests/cases/compiler/moduleVisibilityTest3.ts(21,22): error TS2694: Namespace '_
      class Bug {
          constructor(p1: modes, p2: modes.Mode) {// should be an error on p2 - it's not exported
                          ~~~~~
-!!! error TS2304: Cannot find name 'modes'.
+!!! error TS2709: Cannot use namespace 'modes' as a type.
                                           ~~~~
 !!! error TS2694: Namespace '_modes' has no exported member 'Mode'.
              var x:modes.Mode;
diff --git a/tests/baselines/reference/moduleWithValuesAsType.errors.txt b/tests/baselines/reference/moduleWithValuesAsType.errors.txt
index 2bbb94f5076..388e328ade8 100644
--- a/tests/baselines/reference/moduleWithValuesAsType.errors.txt
+++ b/tests/baselines/reference/moduleWithValuesAsType.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/moduleWithValuesAsType.ts(5,8): error TS2304: Cannot find name 'A'.
+tests/cases/compiler/moduleWithValuesAsType.ts(5,8): error TS2709: Cannot use namespace 'A' as a type.
 
 
 ==== tests/cases/compiler/moduleWithValuesAsType.ts (1 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/moduleWithValuesAsType.ts(5,8): error TS2304: Cannot find n
     
     var a: A; // no error
            ~
-!!! error TS2304: Cannot find name 'A'.
\ No newline at end of file
+!!! error TS2709: Cannot use namespace 'A' as a type.
\ No newline at end of file
diff --git a/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.errors.txt b/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.errors.txt
index c686cd7a7cf..bb35b351c1b 100644
--- a/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.errors.txt
+++ b/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.errors.txt
@@ -1,6 +1,5 @@
-tests/cases/conformance/types/typeRelationships/instanceOf/narrowingGenericTypeFromInstanceof01.ts(13,17): error TS2345: Argument of type 'A<T> | B<T>' is not assignable to parameter of type 'A<T>'.
-  Type 'B<T>' is not assignable to type 'A<T>'.
-    Property 'a' is missing in type 'B<T>'.
+tests/cases/conformance/types/typeRelationships/instanceOf/narrowingGenericTypeFromInstanceof01.ts(13,17): error TS2345: Argument of type 'B<T>' is not assignable to parameter of type 'A<{}>'.
+  Property 'a' is missing in type 'B<T>'.
 
 
 ==== tests/cases/conformance/types/typeRelationships/instanceOf/narrowingGenericTypeFromInstanceof01.ts (1 errors) ====
@@ -18,9 +17,8 @@ tests/cases/conformance/types/typeRelationships/instanceOf/narrowingGenericTypeF
         if (x instanceof B) {
             acceptA(x);
                     ~
-!!! error TS2345: Argument of type 'A<T> | B<T>' is not assignable to parameter of type 'A<T>'.
-!!! error TS2345:   Type 'B<T>' is not assignable to type 'A<T>'.
-!!! error TS2345:     Property 'a' is missing in type 'B<T>'.
+!!! error TS2345: Argument of type 'B<T>' is not assignable to parameter of type 'A<{}>'.
+!!! error TS2345:   Property 'a' is missing in type 'B<T>'.
         }
     
         if (x instanceof A) {
diff --git a/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.types b/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.types
index 22d02d17ce1..964c7920a34 100644
--- a/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.types
+++ b/tests/baselines/reference/narrowingGenericTypeFromInstanceof01.types
@@ -43,7 +43,7 @@ function test<T>(x: A<T> | B<T>) {
         acceptA(x);
 >acceptA(x) : any
 >acceptA : <T>(a: A<T>) => void
->x : A<T> | B<T>
+>x : B<T>
     }
 
     if (x instanceof A) {
@@ -65,7 +65,7 @@ function test<T>(x: A<T> | B<T>) {
         acceptB(x);
 >acceptB(x) : void
 >acceptB : <T>(b: B<T>) => void
->x : A<T> | B<T>
+>x : B<T>
     }
 
     if (x instanceof B) {
@@ -76,6 +76,6 @@ function test<T>(x: A<T> | B<T>) {
         acceptB(x);
 >acceptB(x) : void
 >acceptB : <T>(b: B<T>) => void
->x : A<T> | B<T>
+>x : B<T>
     }
 }
diff --git a/tests/baselines/reference/negateOperatorWithEnumType.types b/tests/baselines/reference/negateOperatorWithEnumType.types
index d49f01c7f0d..7d3edbd2680 100644
--- a/tests/baselines/reference/negateOperatorWithEnumType.types
+++ b/tests/baselines/reference/negateOperatorWithEnumType.types
@@ -31,7 +31,7 @@ var ResultIsNumber3 = -(ENUM1.B + ENUM1[""]);
 >ENUM1.B : ENUM1.B
 >ENUM1 : typeof ENUM1
 >B : ENUM1.B
->ENUM1[""] : ENUM1.""
+>ENUM1[""] : ENUM1.
 >ENUM1 : typeof ENUM1
 >"" : ""
 
diff --git a/tests/baselines/reference/neverInference.js b/tests/baselines/reference/neverInference.js
new file mode 100644
index 00000000000..d13e537eba4
--- /dev/null
+++ b/tests/baselines/reference/neverInference.js
@@ -0,0 +1,31 @@
+//// [neverInference.ts]
+declare function f<T>(x: T[]): T;
+
+let neverArray: never[] = [];
+
+let a1 = f([]);  // {}
+let a2 = f(neverArray);  // never
+
+// Repro from #19576
+
+type Comparator<T> = (x: T, y: T) => number;
+
+interface LinkedList<T> {
+    comparator: Comparator<T>,
+    nodes: Node<T>
+}
+
+type Node<T> = { value: T, next: Node<T> } | null
+
+declare function compareNumbers(x: number, y: number): number;
+declare function mkList<T>(items: T[], comparator: Comparator<T>): LinkedList<T>;
+
+const list: LinkedList<number> = mkList([], compareNumbers);
+
+
+//// [neverInference.js]
+"use strict";
+var neverArray = [];
+var a1 = f([]); // {}
+var a2 = f(neverArray); // never
+var list = mkList([], compareNumbers);
diff --git a/tests/baselines/reference/neverInference.symbols b/tests/baselines/reference/neverInference.symbols
new file mode 100644
index 00000000000..683e079b2f8
--- /dev/null
+++ b/tests/baselines/reference/neverInference.symbols
@@ -0,0 +1,76 @@
+=== tests/cases/conformance/types/never/neverInference.ts ===
+declare function f<T>(x: T[]): T;
+>f : Symbol(f, Decl(neverInference.ts, 0, 0))
+>T : Symbol(T, Decl(neverInference.ts, 0, 19))
+>x : Symbol(x, Decl(neverInference.ts, 0, 22))
+>T : Symbol(T, Decl(neverInference.ts, 0, 19))
+>T : Symbol(T, Decl(neverInference.ts, 0, 19))
+
+let neverArray: never[] = [];
+>neverArray : Symbol(neverArray, Decl(neverInference.ts, 2, 3))
+
+let a1 = f([]);  // {}
+>a1 : Symbol(a1, Decl(neverInference.ts, 4, 3))
+>f : Symbol(f, Decl(neverInference.ts, 0, 0))
+
+let a2 = f(neverArray);  // never
+>a2 : Symbol(a2, Decl(neverInference.ts, 5, 3))
+>f : Symbol(f, Decl(neverInference.ts, 0, 0))
+>neverArray : Symbol(neverArray, Decl(neverInference.ts, 2, 3))
+
+// Repro from #19576
+
+type Comparator<T> = (x: T, y: T) => number;
+>Comparator : Symbol(Comparator, Decl(neverInference.ts, 5, 23))
+>T : Symbol(T, Decl(neverInference.ts, 9, 16))
+>x : Symbol(x, Decl(neverInference.ts, 9, 22))
+>T : Symbol(T, Decl(neverInference.ts, 9, 16))
+>y : Symbol(y, Decl(neverInference.ts, 9, 27))
+>T : Symbol(T, Decl(neverInference.ts, 9, 16))
+
+interface LinkedList<T> {
+>LinkedList : Symbol(LinkedList, Decl(neverInference.ts, 9, 44))
+>T : Symbol(T, Decl(neverInference.ts, 11, 21))
+
+    comparator: Comparator<T>,
+>comparator : Symbol(LinkedList.comparator, Decl(neverInference.ts, 11, 25))
+>Comparator : Symbol(Comparator, Decl(neverInference.ts, 5, 23))
+>T : Symbol(T, Decl(neverInference.ts, 11, 21))
+
+    nodes: Node<T>
+>nodes : Symbol(LinkedList.nodes, Decl(neverInference.ts, 12, 30))
+>Node : Symbol(Node, Decl(neverInference.ts, 14, 1))
+>T : Symbol(T, Decl(neverInference.ts, 11, 21))
+}
+
+type Node<T> = { value: T, next: Node<T> } | null
+>Node : Symbol(Node, Decl(neverInference.ts, 14, 1))
+>T : Symbol(T, Decl(neverInference.ts, 16, 10))
+>value : Symbol(value, Decl(neverInference.ts, 16, 16))
+>T : Symbol(T, Decl(neverInference.ts, 16, 10))
+>next : Symbol(next, Decl(neverInference.ts, 16, 26))
+>Node : Symbol(Node, Decl(neverInference.ts, 14, 1))
+>T : Symbol(T, Decl(neverInference.ts, 16, 10))
+
+declare function compareNumbers(x: number, y: number): number;
+>compareNumbers : Symbol(compareNumbers, Decl(neverInference.ts, 16, 49))
+>x : Symbol(x, Decl(neverInference.ts, 18, 32))
+>y : Symbol(y, Decl(neverInference.ts, 18, 42))
+
+declare function mkList<T>(items: T[], comparator: Comparator<T>): LinkedList<T>;
+>mkList : Symbol(mkList, Decl(neverInference.ts, 18, 62))
+>T : Symbol(T, Decl(neverInference.ts, 19, 24))
+>items : Symbol(items, Decl(neverInference.ts, 19, 27))
+>T : Symbol(T, Decl(neverInference.ts, 19, 24))
+>comparator : Symbol(comparator, Decl(neverInference.ts, 19, 38))
+>Comparator : Symbol(Comparator, Decl(neverInference.ts, 5, 23))
+>T : Symbol(T, Decl(neverInference.ts, 19, 24))
+>LinkedList : Symbol(LinkedList, Decl(neverInference.ts, 9, 44))
+>T : Symbol(T, Decl(neverInference.ts, 19, 24))
+
+const list: LinkedList<number> = mkList([], compareNumbers);
+>list : Symbol(list, Decl(neverInference.ts, 21, 5))
+>LinkedList : Symbol(LinkedList, Decl(neverInference.ts, 9, 44))
+>mkList : Symbol(mkList, Decl(neverInference.ts, 18, 62))
+>compareNumbers : Symbol(compareNumbers, Decl(neverInference.ts, 16, 49))
+
diff --git a/tests/baselines/reference/neverInference.types b/tests/baselines/reference/neverInference.types
new file mode 100644
index 00000000000..a7dd05a3f8b
--- /dev/null
+++ b/tests/baselines/reference/neverInference.types
@@ -0,0 +1,83 @@
+=== tests/cases/conformance/types/never/neverInference.ts ===
+declare function f<T>(x: T[]): T;
+>f : <T>(x: T[]) => T
+>T : T
+>x : T[]
+>T : T
+>T : T
+
+let neverArray: never[] = [];
+>neverArray : never[]
+>[] : never[]
+
+let a1 = f([]);  // {}
+>a1 : {}
+>f([]) : {}
+>f : <T>(x: T[]) => T
+>[] : never[]
+
+let a2 = f(neverArray);  // never
+>a2 : never
+>f(neverArray) : never
+>f : <T>(x: T[]) => T
+>neverArray : never[]
+
+// Repro from #19576
+
+type Comparator<T> = (x: T, y: T) => number;
+>Comparator : Comparator<T>
+>T : T
+>x : T
+>T : T
+>y : T
+>T : T
+
+interface LinkedList<T> {
+>LinkedList : LinkedList<T>
+>T : T
+
+    comparator: Comparator<T>,
+>comparator : Comparator<T>
+>Comparator : Comparator<T>
+>T : T
+
+    nodes: Node<T>
+>nodes : Node<T>
+>Node : Node<T>
+>T : T
+}
+
+type Node<T> = { value: T, next: Node<T> } | null
+>Node : Node<T>
+>T : T
+>value : T
+>T : T
+>next : Node<T>
+>Node : Node<T>
+>T : T
+>null : null
+
+declare function compareNumbers(x: number, y: number): number;
+>compareNumbers : (x: number, y: number) => number
+>x : number
+>y : number
+
+declare function mkList<T>(items: T[], comparator: Comparator<T>): LinkedList<T>;
+>mkList : <T>(items: T[], comparator: Comparator<T>) => LinkedList<T>
+>T : T
+>items : T[]
+>T : T
+>comparator : Comparator<T>
+>Comparator : Comparator<T>
+>T : T
+>LinkedList : LinkedList<T>
+>T : T
+
+const list: LinkedList<number> = mkList([], compareNumbers);
+>list : LinkedList<number>
+>LinkedList : LinkedList<T>
+>mkList([], compareNumbers) : LinkedList<number>
+>mkList : <T>(items: T[], comparator: Comparator<T>) => LinkedList<T>
+>[] : never[]
+>compareNumbers : (x: number, y: number) => number
+
diff --git a/tests/baselines/reference/neverTypeErrors1.errors.txt b/tests/baselines/reference/neverTypeErrors1.errors.txt
index a27c6fba065..56233fb6101 100644
--- a/tests/baselines/reference/neverTypeErrors1.errors.txt
+++ b/tests/baselines/reference/neverTypeErrors1.errors.txt
@@ -4,12 +4,13 @@ tests/cases/conformance/types/never/neverTypeErrors1.ts(5,5): error TS2322: Type
 tests/cases/conformance/types/never/neverTypeErrors1.ts(6,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
 tests/cases/conformance/types/never/neverTypeErrors1.ts(7,5): error TS2322: Type 'null' is not assignable to type 'never'.
 tests/cases/conformance/types/never/neverTypeErrors1.ts(8,5): error TS2322: Type '{}' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors1.ts(12,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors1.ts(16,5): error TS2322: Type '1' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors1.ts(19,16): error TS2534: A function returning 'never' cannot have a reachable end point.
+tests/cases/conformance/types/never/neverTypeErrors1.ts(9,5): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'never' has no compatible call signatures.
+tests/cases/conformance/types/never/neverTypeErrors1.ts(13,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
+tests/cases/conformance/types/never/neverTypeErrors1.ts(17,5): error TS2322: Type '1' is not assignable to type 'never'.
+tests/cases/conformance/types/never/neverTypeErrors1.ts(20,16): error TS2534: A function returning 'never' cannot have a reachable end point.
 
 
-==== tests/cases/conformance/types/never/neverTypeErrors1.ts (9 errors) ====
+==== tests/cases/conformance/types/never/neverTypeErrors1.ts (10 errors) ====
     function f1() {
         let x: never;
         x = 1;
@@ -30,6 +31,9 @@ tests/cases/conformance/types/never/neverTypeErrors1.ts(19,16): error TS2534: A
         x = {};
         ~
 !!! error TS2322: Type '{}' is not assignable to type 'never'.
+        x();
+        ~~~
+!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'never' has no compatible call signatures.
     }
     
     function f2(): never {
diff --git a/tests/baselines/reference/neverTypeErrors1.js b/tests/baselines/reference/neverTypeErrors1.js
index 81b3f8f9cdb..4bbe131cd05 100644
--- a/tests/baselines/reference/neverTypeErrors1.js
+++ b/tests/baselines/reference/neverTypeErrors1.js
@@ -7,6 +7,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 
 function f2(): never {
@@ -29,6 +30,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 function f2() {
     return;
diff --git a/tests/baselines/reference/neverTypeErrors1.symbols b/tests/baselines/reference/neverTypeErrors1.symbols
index c9525226aab..eee8e493144 100644
--- a/tests/baselines/reference/neverTypeErrors1.symbols
+++ b/tests/baselines/reference/neverTypeErrors1.symbols
@@ -23,20 +23,23 @@ function f1() {
 
     x = {};
 >x : Symbol(x, Decl(neverTypeErrors1.ts, 1, 7))
+
+    x();
+>x : Symbol(x, Decl(neverTypeErrors1.ts, 1, 7))
 }
 
 function f2(): never {
->f2 : Symbol(f2, Decl(neverTypeErrors1.ts, 8, 1))
+>f2 : Symbol(f2, Decl(neverTypeErrors1.ts, 9, 1))
 
     return;
 }
 
 function f3(): never {
->f3 : Symbol(f3, Decl(neverTypeErrors1.ts, 12, 1))
+>f3 : Symbol(f3, Decl(neverTypeErrors1.ts, 13, 1))
 
     return 1;
 }
 
 function f4(): never {
->f4 : Symbol(f4, Decl(neverTypeErrors1.ts, 16, 1))
+>f4 : Symbol(f4, Decl(neverTypeErrors1.ts, 17, 1))
 }
diff --git a/tests/baselines/reference/neverTypeErrors1.types b/tests/baselines/reference/neverTypeErrors1.types
index 150459b32b3..fe21a8c5ba2 100644
--- a/tests/baselines/reference/neverTypeErrors1.types
+++ b/tests/baselines/reference/neverTypeErrors1.types
@@ -34,6 +34,10 @@ function f1() {
 >x = {} : {}
 >x : never
 >{} : {}
+
+    x();
+>x() : any
+>x : never
 }
 
 function f2(): never {
diff --git a/tests/baselines/reference/neverTypeErrors2.errors.txt b/tests/baselines/reference/neverTypeErrors2.errors.txt
index 5f9bb26344f..eb24ac8251c 100644
--- a/tests/baselines/reference/neverTypeErrors2.errors.txt
+++ b/tests/baselines/reference/neverTypeErrors2.errors.txt
@@ -4,12 +4,13 @@ tests/cases/conformance/types/never/neverTypeErrors2.ts(5,5): error TS2322: Type
 tests/cases/conformance/types/never/neverTypeErrors2.ts(6,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
 tests/cases/conformance/types/never/neverTypeErrors2.ts(7,5): error TS2322: Type 'null' is not assignable to type 'never'.
 tests/cases/conformance/types/never/neverTypeErrors2.ts(8,5): error TS2322: Type '{}' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors2.ts(12,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors2.ts(16,5): error TS2322: Type '1' is not assignable to type 'never'.
-tests/cases/conformance/types/never/neverTypeErrors2.ts(19,16): error TS2534: A function returning 'never' cannot have a reachable end point.
+tests/cases/conformance/types/never/neverTypeErrors2.ts(9,5): error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'never' has no compatible call signatures.
+tests/cases/conformance/types/never/neverTypeErrors2.ts(13,5): error TS2322: Type 'undefined' is not assignable to type 'never'.
+tests/cases/conformance/types/never/neverTypeErrors2.ts(17,5): error TS2322: Type '1' is not assignable to type 'never'.
+tests/cases/conformance/types/never/neverTypeErrors2.ts(20,16): error TS2534: A function returning 'never' cannot have a reachable end point.
 
 
-==== tests/cases/conformance/types/never/neverTypeErrors2.ts (9 errors) ====
+==== tests/cases/conformance/types/never/neverTypeErrors2.ts (10 errors) ====
     function f1() {
         let x: never;
         x = 1;
@@ -30,6 +31,9 @@ tests/cases/conformance/types/never/neverTypeErrors2.ts(19,16): error TS2534: A
         x = {};
         ~
 !!! error TS2322: Type '{}' is not assignable to type 'never'.
+        x();
+        ~~~
+!!! error TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'never' has no compatible call signatures.
     }
     
     function f2(): never {
diff --git a/tests/baselines/reference/neverTypeErrors2.js b/tests/baselines/reference/neverTypeErrors2.js
index 70bdb4673ca..940c4df5556 100644
--- a/tests/baselines/reference/neverTypeErrors2.js
+++ b/tests/baselines/reference/neverTypeErrors2.js
@@ -7,6 +7,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 
 function f2(): never {
@@ -29,6 +30,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 function f2() {
     return;
diff --git a/tests/baselines/reference/neverTypeErrors2.symbols b/tests/baselines/reference/neverTypeErrors2.symbols
index 683751fe663..17433391576 100644
--- a/tests/baselines/reference/neverTypeErrors2.symbols
+++ b/tests/baselines/reference/neverTypeErrors2.symbols
@@ -23,20 +23,23 @@ function f1() {
 
     x = {};
 >x : Symbol(x, Decl(neverTypeErrors2.ts, 1, 7))
+
+    x();
+>x : Symbol(x, Decl(neverTypeErrors2.ts, 1, 7))
 }
 
 function f2(): never {
->f2 : Symbol(f2, Decl(neverTypeErrors2.ts, 8, 1))
+>f2 : Symbol(f2, Decl(neverTypeErrors2.ts, 9, 1))
 
     return;
 }
 
 function f3(): never {
->f3 : Symbol(f3, Decl(neverTypeErrors2.ts, 12, 1))
+>f3 : Symbol(f3, Decl(neverTypeErrors2.ts, 13, 1))
 
     return 1;
 }
 
 function f4(): never {
->f4 : Symbol(f4, Decl(neverTypeErrors2.ts, 16, 1))
+>f4 : Symbol(f4, Decl(neverTypeErrors2.ts, 17, 1))
 }
diff --git a/tests/baselines/reference/neverTypeErrors2.types b/tests/baselines/reference/neverTypeErrors2.types
index 071f1779a43..9e45bf1aeba 100644
--- a/tests/baselines/reference/neverTypeErrors2.types
+++ b/tests/baselines/reference/neverTypeErrors2.types
@@ -34,6 +34,10 @@ function f1() {
 >x = {} : {}
 >x : never
 >{} : {}
+
+    x();
+>x() : any
+>x : never
 }
 
 function f2(): never {
diff --git a/tests/baselines/reference/newAbstractInstance2.errors.txt b/tests/baselines/reference/newAbstractInstance2.errors.txt
new file mode 100644
index 00000000000..2b2559cc932
--- /dev/null
+++ b/tests/baselines/reference/newAbstractInstance2.errors.txt
@@ -0,0 +1,12 @@
+/b.ts(2,1): error TS2511: Cannot create an instance of an abstract class.
+
+
+==== /a.ts (0 errors) ====
+    export default abstract class {}
+    
+==== /b.ts (1 errors) ====
+    import A from "./a";
+    new A();
+    ~~~~~~~
+!!! error TS2511: Cannot create an instance of an abstract class.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/newAbstractInstance2.js b/tests/baselines/reference/newAbstractInstance2.js
new file mode 100644
index 00000000000..2be1012fcd5
--- /dev/null
+++ b/tests/baselines/reference/newAbstractInstance2.js
@@ -0,0 +1,24 @@
+//// [tests/cases/compiler/newAbstractInstance2.ts] ////
+
+//// [a.ts]
+export default abstract class {}
+
+//// [b.ts]
+import A from "./a";
+new A();
+
+
+//// [a.js]
+"use strict";
+exports.__esModule = true;
+var default_1 = /** @class */ (function () {
+    function default_1() {
+    }
+    return default_1;
+}());
+exports["default"] = default_1;
+//// [b.js]
+"use strict";
+exports.__esModule = true;
+var a_1 = require("./a");
+new a_1["default"]();
diff --git a/tests/baselines/reference/newAbstractInstance2.symbols b/tests/baselines/reference/newAbstractInstance2.symbols
new file mode 100644
index 00000000000..2ce91130095
--- /dev/null
+++ b/tests/baselines/reference/newAbstractInstance2.symbols
@@ -0,0 +1,10 @@
+=== /a.ts ===
+export default abstract class {}
+No type information for this code.
+No type information for this code.=== /b.ts ===
+import A from "./a";
+>A : Symbol(A, Decl(b.ts, 0, 6))
+
+new A();
+>A : Symbol(A, Decl(b.ts, 0, 6))
+
diff --git a/tests/baselines/reference/newAbstractInstance2.types b/tests/baselines/reference/newAbstractInstance2.types
new file mode 100644
index 00000000000..8e980d90300
--- /dev/null
+++ b/tests/baselines/reference/newAbstractInstance2.types
@@ -0,0 +1,11 @@
+=== /a.ts ===
+export default abstract class {}
+No type information for this code.
+No type information for this code.=== /b.ts ===
+import A from "./a";
+>A : typeof A
+
+new A();
+>new A() : any
+>A : typeof A
+
diff --git a/tests/baselines/reference/newTarget.es5.js b/tests/baselines/reference/newTarget.es5.js
index 61b3f73a9b4..0ee9a7e339e 100644
--- a/tests/baselines/reference/newTarget.es5.js
+++ b/tests/baselines/reference/newTarget.es5.js
@@ -69,11 +69,11 @@ function f1() {
     var g = _newTarget;
     var h = function () { return _newTarget; };
 }
-var f2 = function _a() {
-    var _newTarget = this && this instanceof _a ? this.constructor : void 0;
+var f2 = function _b() {
+    var _newTarget = this && this instanceof _b ? this.constructor : void 0;
     var i = _newTarget;
     var j = function () { return _newTarget; };
 };
 var O = {
-    k: function _b() { var _newTarget = this && this instanceof _b ? this.constructor : void 0; return _newTarget; }
+    k: function _c() { var _newTarget = this && this instanceof _c ? this.constructor : void 0; return _newTarget; }
 };
diff --git a/tests/baselines/reference/noCrashOnImportShadowing.errors.txt b/tests/baselines/reference/noCrashOnImportShadowing.errors.txt
index c1d1dbcdef1..ddd49c0c2c7 100644
--- a/tests/baselines/reference/noCrashOnImportShadowing.errors.txt
+++ b/tests/baselines/reference/noCrashOnImportShadowing.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/index.ts(4,1): error TS2693: 'B' only refers to a type, but is being used as a value here.
-tests/cases/compiler/index.ts(9,10): error TS2304: Cannot find name 'OriginalB'.
+tests/cases/compiler/index.ts(9,10): error TS2709: Cannot use namespace 'OriginalB' as a type.
 
 
 ==== tests/cases/compiler/b.ts (0 errors) ====
@@ -30,4 +30,4 @@ tests/cases/compiler/index.ts(9,10): error TS2304: Cannot find name 'OriginalB'.
     
     const y: OriginalB = x;
              ~~~~~~~~~
-!!! error TS2304: Cannot find name 'OriginalB'.
\ No newline at end of file
+!!! error TS2709: Cannot use namespace 'OriginalB' as a type.
\ No newline at end of file
diff --git a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.js b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.js
index 3259b3287fa..5712fb7c244 100644
--- a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.js
+++ b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.js
@@ -1,20 +1,20 @@
 //// [nominalSubtypeCheckOfTypeParameter.ts]
-interface Tuple<T, S> {
+interface BinaryTuple<T, S> {
     first: T
-      second: S
+    second: S
 }
 
 interface Sequence<T> {
     hasNext(): boolean
-      pop(): T
-      zip<S>(seq: Sequence<S>): Sequence<Tuple<T, S>>
+    pop(): T
+    zip<S>(seq: Sequence<S>): Sequence<BinaryTuple<T, S>>
 }
 
 // error, despite the fact that the code explicitly says List<T> extends Sequence<T>, the current rules for infinitely expanding type references 
 // perform nominal subtyping checks that allow variance for type arguments, but not nominal subtyping for the generic type itself
 interface List<T> extends Sequence<T> {
     getLength(): number
-      zip<S>(seq: Sequence<S>): List<Tuple<T, S>>
+    zip<S>(seq: Sequence<S>): List<BinaryTuple<T, S>>
 }
 
 
diff --git a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.symbols b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.symbols
index c7d9a1b50f4..3d24b82aa8f 100644
--- a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.symbols
+++ b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.symbols
@@ -1,16 +1,16 @@
 === tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts ===
-interface Tuple<T, S> {
->Tuple : Symbol(Tuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
->T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 16))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 18))
+interface BinaryTuple<T, S> {
+>BinaryTuple : Symbol(BinaryTuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
+>T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 22))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 24))
 
     first: T
->first : Symbol(Tuple.first, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 23))
->T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 16))
+>first : Symbol(BinaryTuple.first, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 29))
+>T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 22))
 
-      second: S
->second : Symbol(Tuple.second, Decl(nominalSubtypeCheckOfTypeParameter.ts, 1, 12))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 18))
+    second: S
+>second : Symbol(BinaryTuple.second, Decl(nominalSubtypeCheckOfTypeParameter.ts, 1, 12))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 24))
 }
 
 interface Sequence<T> {
@@ -20,20 +20,20 @@ interface Sequence<T> {
     hasNext(): boolean
 >hasNext : Symbol(Sequence.hasNext, Decl(nominalSubtypeCheckOfTypeParameter.ts, 5, 23))
 
-      pop(): T
+    pop(): T
 >pop : Symbol(Sequence.pop, Decl(nominalSubtypeCheckOfTypeParameter.ts, 6, 22))
 >T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 5, 19))
 
-      zip<S>(seq: Sequence<S>): Sequence<Tuple<T, S>>
->zip : Symbol(Sequence.zip, Decl(nominalSubtypeCheckOfTypeParameter.ts, 7, 14))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 10))
->seq : Symbol(seq, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 13))
+    zip<S>(seq: Sequence<S>): Sequence<BinaryTuple<T, S>>
+>zip : Symbol(Sequence.zip, Decl(nominalSubtypeCheckOfTypeParameter.ts, 7, 12))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 8))
+>seq : Symbol(seq, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 11))
 >Sequence : Symbol(Sequence, Decl(nominalSubtypeCheckOfTypeParameter.ts, 3, 1))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 10))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 8))
 >Sequence : Symbol(Sequence, Decl(nominalSubtypeCheckOfTypeParameter.ts, 3, 1))
->Tuple : Symbol(Tuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
+>BinaryTuple : Symbol(BinaryTuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
 >T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 5, 19))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 10))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 8, 8))
 }
 
 // error, despite the fact that the code explicitly says List<T> extends Sequence<T>, the current rules for infinitely expanding type references 
@@ -47,15 +47,15 @@ interface List<T> extends Sequence<T> {
     getLength(): number
 >getLength : Symbol(List.getLength, Decl(nominalSubtypeCheckOfTypeParameter.ts, 13, 39))
 
-      zip<S>(seq: Sequence<S>): List<Tuple<T, S>>
+    zip<S>(seq: Sequence<S>): List<BinaryTuple<T, S>>
 >zip : Symbol(List.zip, Decl(nominalSubtypeCheckOfTypeParameter.ts, 14, 23))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 10))
->seq : Symbol(seq, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 13))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 8))
+>seq : Symbol(seq, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 11))
 >Sequence : Symbol(Sequence, Decl(nominalSubtypeCheckOfTypeParameter.ts, 3, 1))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 10))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 8))
 >List : Symbol(List, Decl(nominalSubtypeCheckOfTypeParameter.ts, 9, 1))
->Tuple : Symbol(Tuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
+>BinaryTuple : Symbol(BinaryTuple, Decl(nominalSubtypeCheckOfTypeParameter.ts, 0, 0))
 >T : Symbol(T, Decl(nominalSubtypeCheckOfTypeParameter.ts, 13, 15))
->S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 10))
+>S : Symbol(S, Decl(nominalSubtypeCheckOfTypeParameter.ts, 15, 8))
 }
 
diff --git a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.types b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.types
index 79b2ac77d78..5da84d0c8a4 100644
--- a/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.types
+++ b/tests/baselines/reference/nominalSubtypeCheckOfTypeParameter.types
@@ -1,6 +1,6 @@
 === tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts ===
-interface Tuple<T, S> {
->Tuple : Tuple<T, S>
+interface BinaryTuple<T, S> {
+>BinaryTuple : BinaryTuple<T, S>
 >T : T
 >S : S
 
@@ -8,7 +8,7 @@ interface Tuple<T, S> {
 >first : T
 >T : T
 
-      second: S
+    second: S
 >second : S
 >S : S
 }
@@ -20,18 +20,18 @@ interface Sequence<T> {
     hasNext(): boolean
 >hasNext : () => boolean
 
-      pop(): T
+    pop(): T
 >pop : () => T
 >T : T
 
-      zip<S>(seq: Sequence<S>): Sequence<Tuple<T, S>>
->zip : <S>(seq: Sequence<S>) => Sequence<Tuple<T, S>>
+    zip<S>(seq: Sequence<S>): Sequence<BinaryTuple<T, S>>
+>zip : <S>(seq: Sequence<S>) => Sequence<BinaryTuple<T, S>>
 >S : S
 >seq : Sequence<S>
 >Sequence : Sequence<T>
 >S : S
 >Sequence : Sequence<T>
->Tuple : Tuple<T, S>
+>BinaryTuple : BinaryTuple<T, S>
 >T : T
 >S : S
 }
@@ -47,14 +47,14 @@ interface List<T> extends Sequence<T> {
     getLength(): number
 >getLength : () => number
 
-      zip<S>(seq: Sequence<S>): List<Tuple<T, S>>
->zip : <S>(seq: Sequence<S>) => List<Tuple<T, S>>
+    zip<S>(seq: Sequence<S>): List<BinaryTuple<T, S>>
+>zip : <S>(seq: Sequence<S>) => List<BinaryTuple<T, S>>
 >S : S
 >seq : Sequence<S>
 >Sequence : Sequence<T>
 >S : S
 >List : List<T>
->Tuple : Tuple<T, S>
+>BinaryTuple : BinaryTuple<T, S>
 >T : T
 >S : S
 }
diff --git a/tests/baselines/reference/nonContextuallyTypedLogicalOr.symbols b/tests/baselines/reference/nonContextuallyTypedLogicalOr.symbols
index 43d7539b6b9..2d921f6631c 100644
--- a/tests/baselines/reference/nonContextuallyTypedLogicalOr.symbols
+++ b/tests/baselines/reference/nonContextuallyTypedLogicalOr.symbols
@@ -28,8 +28,8 @@ var e: Ellement;
 >Ellement : Symbol(Ellement, Decl(nonContextuallyTypedLogicalOr.ts, 3, 1))
 
 (c || e).dummy;
->(c || e).dummy : Symbol(Contextual.dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22))
+>(c || e).dummy : Symbol(dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22), Decl(nonContextuallyTypedLogicalOr.ts, 5, 20))
 >c : Symbol(c, Decl(nonContextuallyTypedLogicalOr.ts, 10, 3))
 >e : Symbol(e, Decl(nonContextuallyTypedLogicalOr.ts, 11, 3))
->dummy : Symbol(Contextual.dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22))
+>dummy : Symbol(dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22), Decl(nonContextuallyTypedLogicalOr.ts, 5, 20))
 
diff --git a/tests/baselines/reference/nonContextuallyTypedLogicalOr.types b/tests/baselines/reference/nonContextuallyTypedLogicalOr.types
index 5061ad1d975..aeb9d1409c6 100644
--- a/tests/baselines/reference/nonContextuallyTypedLogicalOr.types
+++ b/tests/baselines/reference/nonContextuallyTypedLogicalOr.types
@@ -29,8 +29,8 @@ var e: Ellement;
 
 (c || e).dummy;
 >(c || e).dummy : any
->(c || e) : Contextual
->c || e : Contextual
+>(c || e) : Contextual | Ellement
+>c || e : Contextual | Ellement
 >c : Contextual
 >e : Ellement
 >dummy : any
diff --git a/tests/baselines/reference/nullAssignableToEveryType.js b/tests/baselines/reference/nullAssignableToEveryType.js
index f04ae865692..50914b366f8 100644
--- a/tests/baselines/reference/nullAssignableToEveryType.js
+++ b/tests/baselines/reference/nullAssignableToEveryType.js
@@ -84,4 +84,4 @@ function foo(x, y, z) {
 //    x = null;
 //    y = null;
 //    z = null;
-//} 
+//}
diff --git a/tests/baselines/reference/objectLiteralNormalization.errors.txt b/tests/baselines/reference/objectLiteralNormalization.errors.txt
new file mode 100644
index 00000000000..6bdc9b955e3
--- /dev/null
+++ b/tests/baselines/reference/objectLiteralNormalization.errors.txt
@@ -0,0 +1,92 @@
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(7,1): error TS2322: Type '{ a: number; b: number; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+  Type '{ a: number; b: number; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+    Property 'c' is missing in type '{ a: number; b: number; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(8,1): error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+  Type '{ b: string; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+    Property 'a' is missing in type '{ b: string; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(9,1): error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+  Type '{ c: true; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+    Property 'a' is missing in type '{ c: true; }'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(17,1): error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+  Type '{ a: string; b: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
+    Types of property 'a' are incompatible.
+      Type 'string' is not assignable to type 'undefined'.
+tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts(18,1): error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+  Type '{ a: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
+    Types of property 'a' are incompatible.
+      Type 'number' is not assignable to type 'undefined'.
+
+
+==== tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts (5 errors) ====
+    // Object literals in unions are normalized upon widening
+    let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+    a1.a;  // number
+    a1.b;  // string | undefined
+    a1.c;  // boolean | undefined
+    a1 = { a: 1 };
+    a1 = { a: 0, b: 0 };  // Error
+    ~~
+!!! error TS2322: Type '{ a: number; b: number; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+!!! error TS2322:   Type '{ a: number; b: number; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+!!! error TS2322:     Property 'c' is missing in type '{ a: number; b: number; }'.
+    a1 = { b: "y" };  // Error
+    ~~
+!!! error TS2322: Type '{ b: string; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+!!! error TS2322:   Type '{ b: string; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+!!! error TS2322:     Property 'a' is missing in type '{ b: string; }'.
+    a1 = { c: true };  // Error
+    ~~
+!!! error TS2322: Type '{ c: true; }' is not assignable to type '{ a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }'.
+!!! error TS2322:   Type '{ c: true; }' is not assignable to type '{ a: number; b: string; c: boolean; }'.
+!!! error TS2322:     Property 'a' is missing in type '{ c: true; }'.
+    
+    let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+    a2.a;  // string | number | undefined
+    a2.b;  // number | undefined
+    a2 = { a: 10, b: 20 };
+    a2 = { a: "def" };
+    a2 = {};
+    a2 = { a: "def", b: 20 };  // Error
+    ~~
+!!! error TS2322: Type '{ a: string; b: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+!!! error TS2322:   Type '{ a: string; b: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
+!!! error TS2322:     Types of property 'a' are incompatible.
+!!! error TS2322:       Type 'string' is not assignable to type 'undefined'.
+    a2 = { a: 1 };  // Error
+    ~~
+!!! error TS2322: Type '{ a: number; }' is not assignable to type '{ a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }'.
+!!! error TS2322:   Type '{ a: number; }' is not assignable to type '{ a?: undefined; b?: undefined; }'.
+!!! error TS2322:     Types of property 'a' are incompatible.
+!!! error TS2322:       Type 'number' is not assignable to type 'undefined'.
+    
+    // Object literals containing spreads are not normalized
+    declare let b1: { a: string, b: string } | { b: string, c: string };
+    let b2 = { ...b1, z: 55 };
+    let b3 = { ...b2 };
+    
+    // Before widening {} acts like { [x: string]: undefined }, which is a
+    // subtype of types with all optional properties
+    declare let opts: { foo?: string, bar?: string, baz?: boolean };
+    let c1 = !true ? {} : opts;
+    let c2 = !true ? opts : {};
+    let c3 = !true ? { a: 0, b: 0 } : {};
+    let c4 = !true ? {} : { a: 0, b: 0 };
+    
+    // Normalization applies to nested properties
+    let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+    d1.kind;
+    d1.pos;
+    d1.pos.x;
+    d1.pos.y;
+    d1.pos.a;
+    d1.pos.b;
+    
+    declare function f<T>(...items: T[]): T;
+    declare let data: { a: 1, b: "abc", c: true };
+    
+    // Object literals are inferred as a single normalized union type
+    let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+    let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+    let e3 = f(data, { a: 2 });
+    let e4 = f({ a: 2 }, data);
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralNormalization.js b/tests/baselines/reference/objectLiteralNormalization.js
new file mode 100644
index 00000000000..153ed72b5b3
--- /dev/null
+++ b/tests/baselines/reference/objectLiteralNormalization.js
@@ -0,0 +1,232 @@
+//// [objectLiteralNormalization.ts]
+// Object literals in unions are normalized upon widening
+let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+a1.a;  // number
+a1.b;  // string | undefined
+a1.c;  // boolean | undefined
+a1 = { a: 1 };
+a1 = { a: 0, b: 0 };  // Error
+a1 = { b: "y" };  // Error
+a1 = { c: true };  // Error
+
+let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+a2.a;  // string | number | undefined
+a2.b;  // number | undefined
+a2 = { a: 10, b: 20 };
+a2 = { a: "def" };
+a2 = {};
+a2 = { a: "def", b: 20 };  // Error
+a2 = { a: 1 };  // Error
+
+// Object literals containing spreads are not normalized
+declare let b1: { a: string, b: string } | { b: string, c: string };
+let b2 = { ...b1, z: 55 };
+let b3 = { ...b2 };
+
+// Before widening {} acts like { [x: string]: undefined }, which is a
+// subtype of types with all optional properties
+declare let opts: { foo?: string, bar?: string, baz?: boolean };
+let c1 = !true ? {} : opts;
+let c2 = !true ? opts : {};
+let c3 = !true ? { a: 0, b: 0 } : {};
+let c4 = !true ? {} : { a: 0, b: 0 };
+
+// Normalization applies to nested properties
+let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+d1.kind;
+d1.pos;
+d1.pos.x;
+d1.pos.y;
+d1.pos.a;
+d1.pos.b;
+
+declare function f<T>(...items: T[]): T;
+declare let data: { a: 1, b: "abc", c: true };
+
+// Object literals are inferred as a single normalized union type
+let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+let e3 = f(data, { a: 2 });
+let e4 = f({ a: 2 }, data);
+
+
+//// [objectLiteralNormalization.js]
+"use strict";
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+// Object literals in unions are normalized upon widening
+var a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+a1.a; // number
+a1.b; // string | undefined
+a1.c; // boolean | undefined
+a1 = { a: 1 };
+a1 = { a: 0, b: 0 }; // Error
+a1 = { b: "y" }; // Error
+a1 = { c: true }; // Error
+var a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+a2.a; // string | number | undefined
+a2.b; // number | undefined
+a2 = { a: 10, b: 20 };
+a2 = { a: "def" };
+a2 = {};
+a2 = { a: "def", b: 20 }; // Error
+a2 = { a: 1 }; // Error
+var b2 = __assign({}, b1, { z: 55 });
+var b3 = __assign({}, b2);
+var c1 = !true ? {} : opts;
+var c2 = !true ? opts : {};
+var c3 = !true ? { a: 0, b: 0 } : {};
+var c4 = !true ? {} : { a: 0, b: 0 };
+// Normalization applies to nested properties
+var d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+d1.kind;
+d1.pos;
+d1.pos.x;
+d1.pos.y;
+d1.pos.a;
+d1.pos.b;
+// Object literals are inferred as a single normalized union type
+var e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+var e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+var e3 = f(data, { a: 2 });
+var e4 = f({ a: 2 }, data);
+
+
+//// [objectLiteralNormalization.d.ts]
+declare let a1: {
+    a: number;
+    b?: undefined;
+    c?: undefined;
+} | {
+    a: number;
+    b: string;
+    c?: undefined;
+} | {
+    a: number;
+    b: string;
+    c: boolean;
+};
+declare let a2: {
+    a: number;
+    b: number;
+} | {
+    a: string;
+    b?: undefined;
+} | {
+    a?: undefined;
+    b?: undefined;
+};
+declare let b1: {
+    a: string;
+    b: string;
+} | {
+    b: string;
+    c: string;
+};
+declare let b2: {
+    z: number;
+    a: string;
+    b: string;
+} | {
+    z: number;
+    b: string;
+    c: string;
+};
+declare let b3: {
+    z: number;
+    a: string;
+    b: string;
+} | {
+    z: number;
+    b: string;
+    c: string;
+};
+declare let opts: {
+    foo?: string;
+    bar?: string;
+    baz?: boolean;
+};
+declare let c1: {
+    foo?: string | undefined;
+    bar?: string | undefined;
+    baz?: boolean | undefined;
+};
+declare let c2: {
+    foo?: string | undefined;
+    bar?: string | undefined;
+    baz?: boolean | undefined;
+};
+declare let c3: {
+    a: number;
+    b: number;
+} | {
+    a?: undefined;
+    b?: undefined;
+};
+declare let c4: {
+    a?: undefined;
+    b?: undefined;
+} | {
+    a: number;
+    b: number;
+};
+declare let d1: {
+    kind: string;
+    pos: {
+        x: number;
+        y: number;
+        a?: undefined;
+        b?: undefined;
+    };
+} | {
+    kind: string;
+    pos: {
+        a: string;
+        x?: undefined;
+        y?: undefined;
+        b?: undefined;
+    } | {
+        b: number;
+        x?: undefined;
+        y?: undefined;
+        a?: undefined;
+    };
+};
+declare function f<T>(...items: T[]): T;
+declare let data: {
+    a: 1;
+    b: "abc";
+    c: true;
+};
+declare let e1: {
+    a: number;
+    b: number;
+} | {
+    a: string;
+    b?: undefined;
+} | {
+    a?: undefined;
+    b?: undefined;
+};
+declare let e2: {
+    a?: undefined;
+    b?: undefined;
+} | {
+    a: string;
+    b?: undefined;
+} | {
+    a: number;
+    b: number;
+};
+declare let e3: {
+    a: number;
+};
+declare let e4: {
+    a: number;
+};
diff --git a/tests/baselines/reference/objectLiteralNormalization.symbols b/tests/baselines/reference/objectLiteralNormalization.symbols
new file mode 100644
index 00000000000..69882d81f76
--- /dev/null
+++ b/tests/baselines/reference/objectLiteralNormalization.symbols
@@ -0,0 +1,213 @@
+=== tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts ===
+// Object literals in unions are normalized upon widening
+let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 1, 11))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 1, 21))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 1, 27))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 1, 39))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 1, 45))
+>c : Symbol(c, Decl(objectLiteralNormalization.ts, 1, 53))
+
+a1.a;  // number
+>a1.a : Symbol(a, Decl(objectLiteralNormalization.ts, 1, 11), Decl(objectLiteralNormalization.ts, 1, 21), Decl(objectLiteralNormalization.ts, 1, 39))
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 1, 11), Decl(objectLiteralNormalization.ts, 1, 21), Decl(objectLiteralNormalization.ts, 1, 39))
+
+a1.b;  // string | undefined
+>a1.b : Symbol(b, Decl(objectLiteralNormalization.ts, 1, 27), Decl(objectLiteralNormalization.ts, 1, 45))
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 1, 27), Decl(objectLiteralNormalization.ts, 1, 45))
+
+a1.c;  // boolean | undefined
+>a1.c : Symbol(c, Decl(objectLiteralNormalization.ts, 1, 53))
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>c : Symbol(c, Decl(objectLiteralNormalization.ts, 1, 53))
+
+a1 = { a: 1 };
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 5, 6))
+
+a1 = { a: 0, b: 0 };  // Error
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 6, 6))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 6, 12))
+
+a1 = { b: "y" };  // Error
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 7, 6))
+
+a1 = { c: true };  // Error
+>a1 : Symbol(a1, Decl(objectLiteralNormalization.ts, 1, 3))
+>c : Symbol(c, Decl(objectLiteralNormalization.ts, 8, 6))
+
+let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 10, 11))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 10, 17))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 10, 27))
+
+a2.a;  // string | number | undefined
+>a2.a : Symbol(a, Decl(objectLiteralNormalization.ts, 10, 11), Decl(objectLiteralNormalization.ts, 10, 27))
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 10, 11), Decl(objectLiteralNormalization.ts, 10, 27))
+
+a2.b;  // number | undefined
+>a2.b : Symbol(b, Decl(objectLiteralNormalization.ts, 10, 17))
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 10, 17))
+
+a2 = { a: 10, b: 20 };
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 13, 6))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 13, 13))
+
+a2 = { a: "def" };
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 14, 6))
+
+a2 = {};
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+
+a2 = { a: "def", b: 20 };  // Error
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 16, 6))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 16, 16))
+
+a2 = { a: 1 };  // Error
+>a2 : Symbol(a2, Decl(objectLiteralNormalization.ts, 10, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 17, 6))
+
+// Object literals containing spreads are not normalized
+declare let b1: { a: string, b: string } | { b: string, c: string };
+>b1 : Symbol(b1, Decl(objectLiteralNormalization.ts, 20, 11))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 20, 17))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 20, 28))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 20, 44))
+>c : Symbol(c, Decl(objectLiteralNormalization.ts, 20, 55))
+
+let b2 = { ...b1, z: 55 };
+>b2 : Symbol(b2, Decl(objectLiteralNormalization.ts, 21, 3))
+>b1 : Symbol(b1, Decl(objectLiteralNormalization.ts, 20, 11))
+>z : Symbol(z, Decl(objectLiteralNormalization.ts, 21, 17))
+
+let b3 = { ...b2 };
+>b3 : Symbol(b3, Decl(objectLiteralNormalization.ts, 22, 3))
+>b2 : Symbol(b2, Decl(objectLiteralNormalization.ts, 21, 3))
+
+// Before widening {} acts like { [x: string]: undefined }, which is a
+// subtype of types with all optional properties
+declare let opts: { foo?: string, bar?: string, baz?: boolean };
+>opts : Symbol(opts, Decl(objectLiteralNormalization.ts, 26, 11))
+>foo : Symbol(foo, Decl(objectLiteralNormalization.ts, 26, 19))
+>bar : Symbol(bar, Decl(objectLiteralNormalization.ts, 26, 33))
+>baz : Symbol(baz, Decl(objectLiteralNormalization.ts, 26, 47))
+
+let c1 = !true ? {} : opts;
+>c1 : Symbol(c1, Decl(objectLiteralNormalization.ts, 27, 3))
+>opts : Symbol(opts, Decl(objectLiteralNormalization.ts, 26, 11))
+
+let c2 = !true ? opts : {};
+>c2 : Symbol(c2, Decl(objectLiteralNormalization.ts, 28, 3))
+>opts : Symbol(opts, Decl(objectLiteralNormalization.ts, 26, 11))
+
+let c3 = !true ? { a: 0, b: 0 } : {};
+>c3 : Symbol(c3, Decl(objectLiteralNormalization.ts, 29, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 29, 18))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 29, 24))
+
+let c4 = !true ? {} : { a: 0, b: 0 };
+>c4 : Symbol(c4, Decl(objectLiteralNormalization.ts, 30, 3))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 30, 23))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 30, 29))
+
+// Normalization applies to nested properties
+let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>kind : Symbol(kind, Decl(objectLiteralNormalization.ts, 33, 11))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22))
+>x : Symbol(x, Decl(objectLiteralNormalization.ts, 33, 29))
+>y : Symbol(y, Decl(objectLiteralNormalization.ts, 33, 35))
+>kind : Symbol(kind, Decl(objectLiteralNormalization.ts, 33, 47))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 58))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 33, 73))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 33, 86))
+
+d1.kind;
+>d1.kind : Symbol(kind, Decl(objectLiteralNormalization.ts, 33, 11), Decl(objectLiteralNormalization.ts, 33, 47))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>kind : Symbol(kind, Decl(objectLiteralNormalization.ts, 33, 11), Decl(objectLiteralNormalization.ts, 33, 47))
+
+d1.pos;
+>d1.pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+
+d1.pos.x;
+>d1.pos.x : Symbol(x, Decl(objectLiteralNormalization.ts, 33, 29))
+>d1.pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>x : Symbol(x, Decl(objectLiteralNormalization.ts, 33, 29))
+
+d1.pos.y;
+>d1.pos.y : Symbol(y, Decl(objectLiteralNormalization.ts, 33, 35))
+>d1.pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>y : Symbol(y, Decl(objectLiteralNormalization.ts, 33, 35))
+
+d1.pos.a;
+>d1.pos.a : Symbol(a, Decl(objectLiteralNormalization.ts, 33, 73))
+>d1.pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 33, 73))
+
+d1.pos.b;
+>d1.pos.b : Symbol(b, Decl(objectLiteralNormalization.ts, 33, 86))
+>d1.pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>d1 : Symbol(d1, Decl(objectLiteralNormalization.ts, 33, 3))
+>pos : Symbol(pos, Decl(objectLiteralNormalization.ts, 33, 22), Decl(objectLiteralNormalization.ts, 33, 58))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 33, 86))
+
+declare function f<T>(...items: T[]): T;
+>f : Symbol(f, Decl(objectLiteralNormalization.ts, 39, 9))
+>T : Symbol(T, Decl(objectLiteralNormalization.ts, 41, 19))
+>items : Symbol(items, Decl(objectLiteralNormalization.ts, 41, 22))
+>T : Symbol(T, Decl(objectLiteralNormalization.ts, 41, 19))
+>T : Symbol(T, Decl(objectLiteralNormalization.ts, 41, 19))
+
+declare let data: { a: 1, b: "abc", c: true };
+>data : Symbol(data, Decl(objectLiteralNormalization.ts, 42, 11))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 42, 19))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 42, 25))
+>c : Symbol(c, Decl(objectLiteralNormalization.ts, 42, 35))
+
+// Object literals are inferred as a single normalized union type
+let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+>e1 : Symbol(e1, Decl(objectLiteralNormalization.ts, 45, 3))
+>f : Symbol(f, Decl(objectLiteralNormalization.ts, 39, 9))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 45, 12))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 45, 18))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 45, 28))
+
+let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+>e2 : Symbol(e2, Decl(objectLiteralNormalization.ts, 46, 3))
+>f : Symbol(f, Decl(objectLiteralNormalization.ts, 39, 9))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 46, 16))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 46, 30))
+>b : Symbol(b, Decl(objectLiteralNormalization.ts, 46, 36))
+
+let e3 = f(data, { a: 2 });
+>e3 : Symbol(e3, Decl(objectLiteralNormalization.ts, 47, 3))
+>f : Symbol(f, Decl(objectLiteralNormalization.ts, 39, 9))
+>data : Symbol(data, Decl(objectLiteralNormalization.ts, 42, 11))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 47, 18))
+
+let e4 = f({ a: 2 }, data);
+>e4 : Symbol(e4, Decl(objectLiteralNormalization.ts, 48, 3))
+>f : Symbol(f, Decl(objectLiteralNormalization.ts, 39, 9))
+>a : Symbol(a, Decl(objectLiteralNormalization.ts, 48, 12))
+>data : Symbol(data, Decl(objectLiteralNormalization.ts, 42, 11))
+
diff --git a/tests/baselines/reference/objectLiteralNormalization.types b/tests/baselines/reference/objectLiteralNormalization.types
new file mode 100644
index 00000000000..8fa49c9d9ac
--- /dev/null
+++ b/tests/baselines/reference/objectLiteralNormalization.types
@@ -0,0 +1,326 @@
+=== tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts ===
+// Object literals in unions are normalized upon widening
+let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>[{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0] : { a: number; } | { a: number; b: string; } | { a: number; b: string; c: boolean; }
+>[{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }] : ({ a: number; } | { a: number; b: string; } | { a: number; b: string; c: boolean; })[]
+>{ a: 0 } : { a: number; }
+>a : number
+>0 : 0
+>{ a: 1, b: "x" } : { a: number; b: string; }
+>a : number
+>1 : 1
+>b : string
+>"x" : "x"
+>{ a: 2, b: "y", c: true } : { a: number; b: string; c: boolean; }
+>a : number
+>2 : 2
+>b : string
+>"y" : "y"
+>c : boolean
+>true : true
+>0 : 0
+
+a1.a;  // number
+>a1.a : number
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>a : number
+
+a1.b;  // string | undefined
+>a1.b : string | undefined
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>b : string | undefined
+
+a1.c;  // boolean | undefined
+>a1.c : boolean | undefined
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>c : boolean | undefined
+
+a1 = { a: 1 };
+>a1 = { a: 1 } : { a: number; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>{ a: 1 } : { a: number; }
+>a : number
+>1 : 1
+
+a1 = { a: 0, b: 0 };  // Error
+>a1 = { a: 0, b: 0 } : { a: number; b: number; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>{ a: 0, b: 0 } : { a: number; b: number; }
+>a : number
+>0 : 0
+>b : number
+>0 : 0
+
+a1 = { b: "y" };  // Error
+>a1 = { b: "y" } : { b: string; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>{ b: "y" } : { b: string; }
+>b : string
+>"y" : "y"
+
+a1 = { c: true };  // Error
+>a1 = { c: true } : { c: true; }
+>a1 : { a: number; b?: undefined; c?: undefined; } | { a: number; b: string; c?: undefined; } | { a: number; b: string; c: boolean; }
+>{ c: true } : { c: true; }
+>c : boolean
+>true : true
+
+let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>[{ a: 1, b: 2 }, { a: "abc" }, {}][0] : { a: number; b: number; } | { a: string; } | {}
+>[{ a: 1, b: 2 }, { a: "abc" }, {}] : ({ a: number; b: number; } | { a: string; } | {})[]
+>{ a: 1, b: 2 } : { a: number; b: number; }
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+>{ a: "abc" } : { a: string; }
+>a : string
+>"abc" : "abc"
+>{} : {}
+>0 : 0
+
+a2.a;  // string | number | undefined
+>a2.a : string | number | undefined
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>a : string | number | undefined
+
+a2.b;  // number | undefined
+>a2.b : number | undefined
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>b : number | undefined
+
+a2 = { a: 10, b: 20 };
+>a2 = { a: 10, b: 20 } : { a: number; b: number; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>{ a: 10, b: 20 } : { a: number; b: number; }
+>a : number
+>10 : 10
+>b : number
+>20 : 20
+
+a2 = { a: "def" };
+>a2 = { a: "def" } : { a: string; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>{ a: "def" } : { a: string; }
+>a : string
+>"def" : "def"
+
+a2 = {};
+>a2 = {} : {}
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>{} : {}
+
+a2 = { a: "def", b: 20 };  // Error
+>a2 = { a: "def", b: 20 } : { a: string; b: number; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>{ a: "def", b: 20 } : { a: string; b: number; }
+>a : string
+>"def" : "def"
+>b : number
+>20 : 20
+
+a2 = { a: 1 };  // Error
+>a2 = { a: 1 } : { a: number; }
+>a2 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>{ a: 1 } : { a: number; }
+>a : number
+>1 : 1
+
+// Object literals containing spreads are not normalized
+declare let b1: { a: string, b: string } | { b: string, c: string };
+>b1 : { a: string; b: string; } | { b: string; c: string; }
+>a : string
+>b : string
+>b : string
+>c : string
+
+let b2 = { ...b1, z: 55 };
+>b2 : { z: number; a: string; b: string; } | { z: number; b: string; c: string; }
+>{ ...b1, z: 55 } : { z: number; a: string; b: string; } | { z: number; b: string; c: string; }
+>b1 : { a: string; b: string; } | { b: string; c: string; }
+>z : number
+>55 : 55
+
+let b3 = { ...b2 };
+>b3 : { z: number; a: string; b: string; } | { z: number; b: string; c: string; }
+>{ ...b2 } : { z: number; a: string; b: string; } | { z: number; b: string; c: string; }
+>b2 : { z: number; a: string; b: string; } | { z: number; b: string; c: string; }
+
+// Before widening {} acts like { [x: string]: undefined }, which is a
+// subtype of types with all optional properties
+declare let opts: { foo?: string, bar?: string, baz?: boolean };
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>foo : string | undefined
+>bar : string | undefined
+>baz : boolean | undefined
+
+let c1 = !true ? {} : opts;
+>c1 : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true ? {} : opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true : false
+>true : true
+>{} : {}
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+
+let c2 = !true ? opts : {};
+>c2 : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true ? opts : {} : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>!true : false
+>true : true
+>opts : { foo?: string | undefined; bar?: string | undefined; baz?: boolean | undefined; }
+>{} : {}
+
+let c3 = !true ? { a: 0, b: 0 } : {};
+>c3 : { a: number; b: number; } | { a?: undefined; b?: undefined; }
+>!true ? { a: 0, b: 0 } : {} : { a: number; b: number; } | {}
+>!true : false
+>true : true
+>{ a: 0, b: 0 } : { a: number; b: number; }
+>a : number
+>0 : 0
+>b : number
+>0 : 0
+>{} : {}
+
+let c4 = !true ? {} : { a: 0, b: 0 };
+>c4 : { a?: undefined; b?: undefined; } | { a: number; b: number; }
+>!true ? {} : { a: 0, b: 0 } : {} | { a: number; b: number; }
+>!true : false
+>true : true
+>{} : {}
+>{ a: 0, b: 0 } : { a: number; b: number; }
+>a : number
+>0 : 0
+>b : number
+>0 : 0
+
+// Normalization applies to nested properties
+let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>[{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0] : { kind: string; pos: { x: number; y: number; }; } | { kind: string; pos: { a: string; } | { b: number; }; }
+>[{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }] : ({ kind: string; pos: { x: number; y: number; }; } | { kind: string; pos: { a: string; } | { b: number; }; })[]
+>{ kind: 'a', pos: { x: 0, y: 0 } } : { kind: string; pos: { x: number; y: number; }; }
+>kind : string
+>'a' : "a"
+>pos : { x: number; y: number; }
+>{ x: 0, y: 0 } : { x: number; y: number; }
+>x : number
+>0 : 0
+>y : number
+>0 : 0
+>{ kind: 'b', pos: !true ? { a: "x" } : { b: 0 } } : { kind: string; pos: { a: string; } | { b: number; }; }
+>kind : string
+>'b' : "b"
+>pos : { a: string; } | { b: number; }
+>!true ? { a: "x" } : { b: 0 } : { a: string; } | { b: number; }
+>!true : false
+>true : true
+>{ a: "x" } : { a: string; }
+>a : string
+>"x" : "x"
+>{ b: 0 } : { b: number; }
+>b : number
+>0 : 0
+>0 : 0
+
+d1.kind;
+>d1.kind : string
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>kind : string
+
+d1.pos;
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+
+d1.pos.x;
+>d1.pos.x : number | undefined
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>x : number | undefined
+
+d1.pos.y;
+>d1.pos.y : number | undefined
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>y : number | undefined
+
+d1.pos.a;
+>d1.pos.a : string | undefined
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>a : string | undefined
+
+d1.pos.b;
+>d1.pos.b : number | undefined
+>d1.pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>d1 : { kind: string; pos: { x: number; y: number; a?: undefined; b?: undefined; }; } | { kind: string; pos: { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }; }
+>pos : { x: number; y: number; a?: undefined; b?: undefined; } | { a: string; x?: undefined; y?: undefined; b?: undefined; } | { b: number; x?: undefined; y?: undefined; a?: undefined; }
+>b : number | undefined
+
+declare function f<T>(...items: T[]): T;
+>f : <T>(...items: T[]) => T
+>T : T
+>items : T[]
+>T : T
+>T : T
+
+declare let data: { a: 1, b: "abc", c: true };
+>data : { a: 1; b: "abc"; c: true; }
+>a : 1
+>b : "abc"
+>c : true
+>true : true
+
+// Object literals are inferred as a single normalized union type
+let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+>e1 : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>f({ a: 1, b: 2 }, { a: "abc" }, {}) : { a: number; b: number; } | { a: string; b?: undefined; } | { a?: undefined; b?: undefined; }
+>f : <T>(...items: T[]) => T
+>{ a: 1, b: 2 } : { a: number; b: number; }
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+>{ a: "abc" } : { a: string; }
+>a : string
+>"abc" : "abc"
+>{} : {}
+
+let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+>e2 : { a?: undefined; b?: undefined; } | { a: string; b?: undefined; } | { a: number; b: number; }
+>f({}, { a: "abc" }, { a: 1, b: 2 }) : { a?: undefined; b?: undefined; } | { a: string; b?: undefined; } | { a: number; b: number; }
+>f : <T>(...items: T[]) => T
+>{} : {}
+>{ a: "abc" } : { a: string; }
+>a : string
+>"abc" : "abc"
+>{ a: 1, b: 2 } : { a: number; b: number; }
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+
+let e3 = f(data, { a: 2 });
+>e3 : { a: number; }
+>f(data, { a: 2 }) : { a: number; }
+>f : <T>(...items: T[]) => T
+>data : { a: 1; b: "abc"; c: true; }
+>{ a: 2 } : { a: number; }
+>a : number
+>2 : 2
+
+let e4 = f({ a: 2 }, data);
+>e4 : { a: number; }
+>f({ a: 2 }, data) : { a: number; }
+>f : <T>(...items: T[]) => T
+>{ a: 2 } : { a: number; }
+>a : number
+>2 : 2
+>data : { a: 1; b: "abc"; c: true; }
+
diff --git a/tests/baselines/reference/objectSpread.types b/tests/baselines/reference/objectSpread.types
index 0caef49f439..5166ceb54d7 100644
--- a/tests/baselines/reference/objectSpread.types
+++ b/tests/baselines/reference/objectSpread.types
@@ -295,7 +295,7 @@ function conditionalSpreadBoolean(b: boolean) : { x: number, y: number } {
 >14 : 14
     }
     let o2 = { ...b && { x: 21 }}
->o2 : {} | { x: number; }
+>o2 : {}
 >{ ...b && { x: 21 }} : {} | { x: number; }
 >b && { x: 21 } : false | { x: number; }
 >b : boolean
@@ -336,7 +336,7 @@ function conditionalSpreadNumber(nt: number): { x: number, y: number } {
 >nt : number
     }
     let o2 = { ...nt && { x: nt }}
->o2 : {} | { x: number; }
+>o2 : {}
 >{ ...nt && { x: nt }} : {} | { x: number; }
 >nt && { x: nt } : 0 | { x: number; }
 >nt : number
@@ -377,7 +377,7 @@ function conditionalSpreadString(st: string): { x: string, y: number } {
 >st : string
     }
     let o2 = { ...st && { x: st }}
->o2 : {} | { x: string; }
+>o2 : {}
 >{ ...st && { x: st }} : {} | { x: string; }
 >st && { x: st } : "" | { x: string; }
 >st : string
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
index ee7425909c2..dede126d063 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
+++ b/tests/baselines/reference/objectSpreadIndexSignature.errors.txt
@@ -16,4 +16,8 @@ tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts(6,1): error T
     
     declare const b: boolean;
     indexed3 = { ...b ? indexed3 : undefined };
+    
+    declare var roindex: { readonly [x:string]: number };
+    var writable = { ...roindex };
+    writable.a = 0;  // should be ok.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.js b/tests/baselines/reference/objectSpreadIndexSignature.js
index 283129036da..f8663fd836f 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.js
+++ b/tests/baselines/reference/objectSpreadIndexSignature.js
@@ -11,6 +11,10 @@ ii[1001];
 
 declare const b: boolean;
 indexed3 = { ...b ? indexed3 : undefined };
+
+declare var roindex: { readonly [x:string]: number };
+var writable = { ...roindex };
+writable.a = 0;  // should be ok.
 
 
 //// [objectSpreadIndexSignature.js]
@@ -30,3 +34,5 @@ var ii = __assign({}, indexed1, indexed2);
 // both have indexer, so i[1001]: number | boolean
 ii[1001];
 indexed3 = __assign({}, b ? indexed3 : undefined);
+var writable = __assign({}, roindex);
+writable.a = 0; // should be ok.
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.symbols b/tests/baselines/reference/objectSpreadIndexSignature.symbols
index d08cfff53ff..439463c4131 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.symbols
+++ b/tests/baselines/reference/objectSpreadIndexSignature.symbols
@@ -40,3 +40,14 @@ indexed3 = { ...b ? indexed3 : undefined };
 >indexed3 : Symbol(indexed3, Decl(objectSpreadIndexSignature.ts, 2, 11))
 >undefined : Symbol(undefined)
 
+declare var roindex: { readonly [x:string]: number };
+>roindex : Symbol(roindex, Decl(objectSpreadIndexSignature.ts, 13, 11))
+>x : Symbol(x, Decl(objectSpreadIndexSignature.ts, 13, 33))
+
+var writable = { ...roindex };
+>writable : Symbol(writable, Decl(objectSpreadIndexSignature.ts, 14, 3))
+>roindex : Symbol(roindex, Decl(objectSpreadIndexSignature.ts, 13, 11))
+
+writable.a = 0;  // should be ok.
+>writable : Symbol(writable, Decl(objectSpreadIndexSignature.ts, 14, 3))
+
diff --git a/tests/baselines/reference/objectSpreadIndexSignature.types b/tests/baselines/reference/objectSpreadIndexSignature.types
index eff3b04b8f6..3ce4d00584b 100644
--- a/tests/baselines/reference/objectSpreadIndexSignature.types
+++ b/tests/baselines/reference/objectSpreadIndexSignature.types
@@ -50,3 +50,19 @@ indexed3 = { ...b ? indexed3 : undefined };
 >indexed3 : { [n: string]: number; }
 >undefined : undefined
 
+declare var roindex: { readonly [x:string]: number };
+>roindex : { readonly [x: string]: number; }
+>x : string
+
+var writable = { ...roindex };
+>writable : { [x: string]: number; }
+>{ ...roindex } : { [x: string]: number; }
+>roindex : { readonly [x: string]: number; }
+
+writable.a = 0;  // should be ok.
+>writable.a = 0 : 0
+>writable.a : number
+>writable : { [x: string]: number; }
+>a : number
+>0 : 0
+
diff --git a/tests/baselines/reference/parserComputedPropertyName10.js b/tests/baselines/reference/parserComputedPropertyName10.js
index eba480ba810..b6efaf3f5a7 100644
--- a/tests/baselines/reference/parserComputedPropertyName10.js
+++ b/tests/baselines/reference/parserComputedPropertyName10.js
@@ -6,6 +6,8 @@ class C {
 //// [parserComputedPropertyName10.js]
 class C {
     constructor() {
-        this[e] = 1;
+        this[_a] = 1;
     }
 }
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserComputedPropertyName25.js b/tests/baselines/reference/parserComputedPropertyName25.js
index 47670fe14b8..f914d7de8ee 100644
--- a/tests/baselines/reference/parserComputedPropertyName25.js
+++ b/tests/baselines/reference/parserComputedPropertyName25.js
@@ -9,6 +9,8 @@ class C {
 class C {
     constructor() {
         // No ASI
-        this[e] = 0[e2] = 1;
+        this[_a] = 0[e2] = 1;
     }
 }
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserComputedPropertyName27.js b/tests/baselines/reference/parserComputedPropertyName27.js
index f872e95e7e6..7f60ec97b5e 100644
--- a/tests/baselines/reference/parserComputedPropertyName27.js
+++ b/tests/baselines/reference/parserComputedPropertyName27.js
@@ -9,6 +9,8 @@ class C {
 class C {
     constructor() {
         // No ASI
-        this[e] = 0[e2];
+        this[_a] = 0[e2];
     }
 }
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserComputedPropertyName28.js b/tests/baselines/reference/parserComputedPropertyName28.js
index 998f60db914..d01ed38069f 100644
--- a/tests/baselines/reference/parserComputedPropertyName28.js
+++ b/tests/baselines/reference/parserComputedPropertyName28.js
@@ -7,6 +7,8 @@ class C {
 //// [parserComputedPropertyName28.js]
 class C {
     constructor() {
-        this[e] = 0;
+        this[_a] = 0;
     }
 }
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserComputedPropertyName29.js b/tests/baselines/reference/parserComputedPropertyName29.js
index a100cbf1791..d5a00df2256 100644
--- a/tests/baselines/reference/parserComputedPropertyName29.js
+++ b/tests/baselines/reference/parserComputedPropertyName29.js
@@ -9,6 +9,8 @@ class C {
 class C {
     constructor() {
         // yes ASI
-        this[e] = id++;
+        this[_a] = id++;
     }
 }
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserComputedPropertyName33.js b/tests/baselines/reference/parserComputedPropertyName33.js
index ab80967c21a..84520a8eb51 100644
--- a/tests/baselines/reference/parserComputedPropertyName33.js
+++ b/tests/baselines/reference/parserComputedPropertyName33.js
@@ -9,7 +9,9 @@ class C {
 class C {
     constructor() {
         // No ASI
-        this[e] = 0[e2]();
+        this[_a] = 0[e2]();
     }
 }
+_a = e;
 { }
+var _a;
diff --git a/tests/baselines/reference/parserConstructorDeclaration4.errors.txt b/tests/baselines/reference/parserConstructorDeclaration4.errors.txt
index b5329a1cb47..bd27ccbb255 100644
--- a/tests/baselines/reference/parserConstructorDeclaration4.errors.txt
+++ b/tests/baselines/reference/parserConstructorDeclaration4.errors.txt
@@ -1,12 +1,9 @@
 tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration4.ts(2,3): error TS1031: 'declare' modifier cannot appear on a class element.
-tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration4.ts(2,25): error TS1183: An implementation cannot be declared in ambient contexts.
 
 
-==== tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration4.ts (2 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/ConstructorDeclarations/parserConstructorDeclaration4.ts (1 errors) ====
     class C {
       declare constructor() { }
       ~~~~~~~
 !!! error TS1031: 'declare' modifier cannot appear on a class element.
-                            ~
-!!! error TS1183: An implementation cannot be declared in ambient contexts.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserES5ComputedPropertyName10.js b/tests/baselines/reference/parserES5ComputedPropertyName10.js
index 78f819af375..72902c30db9 100644
--- a/tests/baselines/reference/parserES5ComputedPropertyName10.js
+++ b/tests/baselines/reference/parserES5ComputedPropertyName10.js
@@ -6,7 +6,9 @@ class C {
 //// [parserES5ComputedPropertyName10.js]
 var C = /** @class */ (function () {
     function C() {
-        this[e] = 1;
+        this[_a] = 1;
     }
     return C;
 }());
+_a = e;
+var _a;
diff --git a/tests/baselines/reference/parserMemberAccessorDeclaration11.errors.txt b/tests/baselines/reference/parserMemberAccessorDeclaration11.errors.txt
index 5da5e536e06..3a04bfbbd02 100644
--- a/tests/baselines/reference/parserMemberAccessorDeclaration11.errors.txt
+++ b/tests/baselines/reference/parserMemberAccessorDeclaration11.errors.txt
@@ -1,9 +1,12 @@
 tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessorDeclaration11.ts(2,5): error TS1031: 'declare' modifier cannot appear on a class element.
+tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessorDeclaration11.ts(2,17): error TS2378: A 'get' accessor must return a value.
 
 
-==== tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessorDeclaration11.ts (1 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/MemberAccessorDeclarations/parserMemberAccessorDeclaration11.ts (2 errors) ====
     class C {
         declare get Foo() { }
         ~~~~~~~
 !!! error TS1031: 'declare' modifier cannot appear on a class element.
+                    ~~~
+!!! error TS2378: A 'get' accessor must return a value.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserMemberFunctionDeclaration5.errors.txt b/tests/baselines/reference/parserMemberFunctionDeclaration5.errors.txt
index 402355919a0..dc19cb0f855 100644
--- a/tests/baselines/reference/parserMemberFunctionDeclaration5.errors.txt
+++ b/tests/baselines/reference/parserMemberFunctionDeclaration5.errors.txt
@@ -1,12 +1,9 @@
 tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclaration5.ts(2,5): error TS1031: 'declare' modifier cannot appear on a class element.
-tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclaration5.ts(2,19): error TS1183: An implementation cannot be declared in ambient contexts.
 
 
-==== tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclaration5.ts (2 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/MemberFunctionDeclarations/parserMemberFunctionDeclaration5.ts (1 errors) ====
     class C {
         declare Foo() { }
         ~~~~~~~
 !!! error TS1031: 'declare' modifier cannot appear on a class element.
-                      ~
-!!! error TS1183: An implementation cannot be declared in ambient contexts.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/primaryExpressionMods.errors.txt b/tests/baselines/reference/primaryExpressionMods.errors.txt
index 197970591eb..0816c13b897 100644
--- a/tests/baselines/reference/primaryExpressionMods.errors.txt
+++ b/tests/baselines/reference/primaryExpressionMods.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/primaryExpressionMods.ts(7,8): error TS2304: Cannot find name 'M'.
+tests/cases/compiler/primaryExpressionMods.ts(7,8): error TS2709: Cannot use namespace 'M' as a type.
 tests/cases/compiler/primaryExpressionMods.ts(11,8): error TS2503: Cannot find namespace 'm'.
 
 
@@ -11,7 +11,7 @@ tests/cases/compiler/primaryExpressionMods.ts(11,8): error TS2503: Cannot find n
     var p: M.P;             // Used as ModuleName
     var m: M = M;           // Used as TypeName and PrimaryExpression (error on TypeName)
            ~
-!!! error TS2304: Cannot find name 'M'.
+!!! error TS2709: Cannot use namespace 'M' as a type.
     var m2: typeof M = M;   // Used as PrimaryExpression in TypeQuery
     var x1 = M.a;           // Used as PrimaryExpression
     var x2 = m.a;           // Same as M.a
diff --git a/tests/baselines/reference/primitiveMembers.types b/tests/baselines/reference/primitiveMembers.types
index 70ca0eb34e7..cb2a6245dd0 100644
--- a/tests/baselines/reference/primitiveMembers.types
+++ b/tests/baselines/reference/primitiveMembers.types
@@ -78,7 +78,7 @@ var b: Boolean = true;
 
 var n3 = 5 || {};
 >n3 : {}
->5 || {} : {}
+>5 || {} : 5 | {}
 >5 : 5
 >{} : {}
 
diff --git a/tests/baselines/reference/privacyAccessorDeclFile.errors.txt b/tests/baselines/reference/privacyAccessorDeclFile.errors.txt
index 67a62a2269c..92ce3d5c535 100644
--- a/tests/baselines/reference/privacyAccessorDeclFile.errors.txt
+++ b/tests/baselines/reference/privacyAccessorDeclFile.errors.txt
@@ -1,39 +1,39 @@
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(253,44): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(259,31): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(265,20): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(271,13): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(361,48): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(365,35): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(405,44): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(408,31): error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(411,20): error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(414,13): error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(420,48): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(422,35): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(8,40): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(14,27): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(20,16): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(26,9): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(116,44): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(120,31): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(160,40): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(163,27): error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(166,16): error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(169,9): error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(175,44): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(177,31): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(210,44): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(216,31): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(222,20): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(228,13): error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(318,48): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(322,35): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(362,44): error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(365,31): error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(368,20): error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(371,13): error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(377,48): error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
-tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(253,44): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(259,31): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(265,20): error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(271,13): error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(361,48): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(365,35): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(405,44): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(408,31): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(411,20): error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(414,13): error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(420,48): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_GlobalFile.ts(422,35): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(8,40): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(14,27): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(20,16): error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(26,9): error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(116,44): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(120,31): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(160,40): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(163,27): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(166,16): error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(169,9): error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(175,44): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(177,31): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(210,44): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(216,31): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(222,20): error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(228,13): error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(318,48): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(322,35): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(362,44): error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(365,31): error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(368,20): error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(371,13): error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(377,48): error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
+tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
 
 
 ==== tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts (24 errors) ====
@@ -46,7 +46,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
     export class publicClassWithWithPrivateGetAccessorTypes {
         static get myPublicStaticMethod(): privateClass { // Error
                                            ~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
             return null;
         }
         private static get myPrivateStaticMethod(): privateClass {
@@ -54,7 +54,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         }
         get myPublicMethod(): privateClass { // Error
                               ~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
             return null;
         }
         private get myPrivateMethod(): privateClass {
@@ -62,7 +62,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         }
         static get myPublicStaticMethod1() { // Error
                    ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
             return new privateClass();
         }
         private static get myPrivateStaticMethod1() {
@@ -70,7 +70,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         }
         get myPublicMethod1() { // Error
             ~~~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
             return new privateClass();
         }
         private get myPrivateMethod1() {
@@ -162,13 +162,13 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
     export class publicClassWithWithPrivateSetAccessorTypes {
         static set myPublicStaticMethod(param: privateClass) { // Error
                                                ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
         }
         private static set myPrivateStaticMethod(param: privateClass) {
         }
         set myPublicMethod(param: privateClass) { // Error
                                   ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
         }
         private set myPrivateMethod(param: privateClass) {
         }
@@ -210,22 +210,22 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
     export class publicClassWithPrivateModuleGetAccessorTypes {
         static get myPublicStaticMethod(): privateModule.publicClass { // Error
                                            ~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
             return null;
         }
         get myPublicMethod(): privateModule.publicClass { // Error
                               ~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
             return null;
         }
         static get myPublicStaticMethod1() { // Error
                    ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
             return new privateModule.publicClass();
         }
         get myPublicMethod1() { // Error
             ~~~~~~~~~~~~~~~
-!!! error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
             return new privateModule.publicClass();
         }
     }
@@ -233,11 +233,11 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
     export class publicClassWithPrivateModuleSetAccessorTypes {
         static set myPublicStaticMethod(param: privateModule.publicClass) { // Error
                                                ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
         }
         set myPublicMethod(param: privateModule.publicClass) { // Error
                                   ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
         }
     }
     
@@ -272,7 +272,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithWithPrivateGetAccessorTypes {
             static get myPublicStaticMethod(): privateClass { // Error
                                                ~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
                 return null;
             }
             private static get myPrivateStaticMethod(): privateClass {
@@ -280,7 +280,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             get myPublicMethod(): privateClass { // Error
                                   ~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
                 return null;
             }
             private get myPrivateMethod(): privateClass {
@@ -288,7 +288,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             static get myPublicStaticMethod1() { // Error
                        ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
                 return new privateClass();
             }
             private static get myPrivateStaticMethod1() {
@@ -296,7 +296,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             get myPublicMethod1() { // Error
                 ~~~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
                 return new privateClass();
             }
             private get myPrivateMethod1() {
@@ -388,13 +388,13 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithWithPrivateSetAccessorTypes {
             static set myPublicStaticMethod(param: privateClass) { // Error
                                                    ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
             }
             private static set myPrivateStaticMethod(param: privateClass) {
             }
             set myPublicMethod(param: privateClass) { // Error
                                       ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
             }
             private set myPrivateMethod(param: privateClass) {
             }
@@ -436,22 +436,22 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithPrivateModuleGetAccessorTypes {
             static get myPublicStaticMethod(): privateModule.publicClass { // Error
                                                ~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
                 return null;
             }
             get myPublicMethod(): privateModule.publicClass { // Error
                                   ~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
                 return null;
             }
             static get myPublicStaticMethod1() { // Error
                        ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
                 return new privateModule.publicClass();
             }
             get myPublicMethod1() { // Error
                 ~~~~~~~~~~~~~~~
-!!! error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
                 return new privateModule.publicClass();
             }
         }
@@ -459,11 +459,11 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithPrivateModuleSetAccessorTypes {
             static set myPublicStaticMethod(param: privateModule.publicClass) { // Error
                                                    ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
             }
             set myPublicMethod(param: privateModule.publicClass) { // Error
                                       ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
             }
         }
     
@@ -948,7 +948,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithWithPrivateGetAccessorTypes {
             static get myPublicStaticMethod(): privateClass { // Error
                                                ~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
                 return null;
             }
             private static get myPrivateStaticMethod(): privateClass {
@@ -956,7 +956,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             get myPublicMethod(): privateClass { // Error
                                   ~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
                 return null;
             }
             private get myPrivateMethod(): privateClass {
@@ -964,7 +964,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             static get myPublicStaticMethod1() { // Error
                        ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using private name 'privateClass'.
                 return new privateClass();
             }
             private static get myPrivateStaticMethod1() {
@@ -972,7 +972,7 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
             }
             get myPublicMethod1() { // Error
                 ~~~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateClass'.
+!!! error TS4043: Return type of public getter 'myPublicMethod1' from exported class has or is using private name 'privateClass'.
                 return new privateClass();
             }
             private get myPrivateMethod1() {
@@ -1064,13 +1064,13 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithWithPrivateSetAccessorTypes {
             static set myPublicStaticMethod(param: privateClass) { // Error
                                                    ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateClass'.
             }
             private static set myPrivateStaticMethod(param: privateClass) {
             }
             set myPublicMethod(param: privateClass) { // Error
                                       ~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateClass'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateClass'.
             }
             private set myPrivateMethod(param: privateClass) {
             }
@@ -1112,22 +1112,22 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithPrivateModuleGetAccessorTypes {
             static get myPublicStaticMethod(): privateModule.publicClass { // Error
                                                ~~~~~~~~~~~~~
-!!! error TS4040: Return type of public static property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4040: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
                 return null;
             }
             get myPublicMethod(): privateModule.publicClass { // Error
                                   ~~~~~~~~~~~~~
-!!! error TS4043: Return type of public property getter from exported class has or is using private name 'privateModule'.
+!!! error TS4043: Return type of public getter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
                 return null;
             }
             static get myPublicStaticMethod1() { // Error
                        ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4039: Return type of public static property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4039: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
                 return new privateModule.publicClass();
             }
             get myPublicMethod1() { // Error
                 ~~~~~~~~~~~~~~~
-!!! error TS4042: Return type of public property getter from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
+!!! error TS4042: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'privateModule.publicClass' from private module 'privateModule'.
                 return new privateModule.publicClass();
             }
         }
@@ -1135,11 +1135,11 @@ tests/cases/compiler/privacyAccessorDeclFile_externalModule.ts(379,35): error TS
         export class publicClassWithPrivateModuleSetAccessorTypes {
             static set myPublicStaticMethod(param: privateModule.publicClass) { // Error
                                                    ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicStaticMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4035: Parameter type of public static setter 'myPublicStaticMethod' from exported class has or is using private name 'privateModule'.
             }
             set myPublicMethod(param: privateModule.publicClass) { // Error
                                       ~~~~~~~~~~~~~
-!!! error TS4037: Parameter 'myPublicMethod' of public property setter from exported class has or is using private name 'privateModule'.
+!!! error TS4037: Parameter type of public setter 'myPublicMethod' from exported class has or is using private name 'privateModule'.
             }
         }
     
diff --git a/tests/baselines/reference/privacyCannotNameAccessorDeclFile.errors.txt b/tests/baselines/reference/privacyCannotNameAccessorDeclFile.errors.txt
index 6c1763f293e..f2419b360d6 100644
--- a/tests/baselines/reference/privacyCannotNameAccessorDeclFile.errors.txt
+++ b/tests/baselines/reference/privacyCannotNameAccessorDeclFile.errors.txt
@@ -1,11 +1,11 @@
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(3,16): error TS4038: Return type of public static property getter from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(9,9): error TS4041: Return type of public property getter from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(15,16): error TS4038: Return type of public static property getter from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(21,9): error TS4041: Return type of public property getter from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(57,16): error TS4038: Return type of public static property getter from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(60,9): error TS4041: Return type of public property getter from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(63,16): error TS4038: Return type of public static property getter from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
-tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error TS4041: Return type of public property getter from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(3,16): error TS4038: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(9,9): error TS4041: Return type of public getter 'myPublicMethod' from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(15,16): error TS4038: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(21,9): error TS4041: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(57,16): error TS4038: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(60,9): error TS4041: Return type of public getter 'myPublicMethod' from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(63,16): error TS4038: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
+tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error TS4041: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
 
 
 ==== tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts (8 errors) ====
@@ -13,7 +13,7 @@ tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error
     export class publicClassWithWithPrivateGetAccessorTypes {
         static get myPublicStaticMethod() { // Error
                    ~~~~~~~~~~~~~~~~~~~~
-!!! error TS4038: Return type of public static property getter from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+!!! error TS4038: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
             return exporter.createExportedWidget1();
         }
         private static get myPrivateStaticMethod() {
@@ -21,7 +21,7 @@ tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error
         }
         get myPublicMethod() { // Error
             ~~~~~~~~~~~~~~
-!!! error TS4041: Return type of public property getter from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+!!! error TS4041: Return type of public getter 'myPublicMethod' from exported class has or is using name 'Widget1' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
             return exporter.createExportedWidget1();
         }
         private get myPrivateMethod() {
@@ -29,7 +29,7 @@ tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error
         }
         static get myPublicStaticMethod1() { // Error
                    ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4038: Return type of public static property getter from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
+!!! error TS4038: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
             return exporter.createExportedWidget3();
         }
         private static get myPrivateStaticMethod1() {
@@ -37,7 +37,7 @@ tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error
         }
         get myPublicMethod1() { // Error
             ~~~~~~~~~~~~~~~
-!!! error TS4041: Return type of public property getter from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
+!!! error TS4041: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'Widget3' from external module "GlobalWidgets" but cannot be named.
             return exporter.createExportedWidget3();
         }
         private get myPrivateMethod1() {
@@ -75,22 +75,22 @@ tests/cases/compiler/privacyCannotNameAccessorDeclFile_consumer.ts(66,9): error
     export class publicClassWithPrivateModuleGetAccessorTypes {
         static get myPublicStaticMethod() { // Error
                    ~~~~~~~~~~~~~~~~~~~~
-!!! error TS4038: Return type of public static property getter from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+!!! error TS4038: Return type of public static getter 'myPublicStaticMethod' from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
             return exporter.createExportedWidget2();
         }
         get myPublicMethod() { // Error
             ~~~~~~~~~~~~~~
-!!! error TS4041: Return type of public property getter from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
+!!! error TS4041: Return type of public getter 'myPublicMethod' from exported class has or is using name 'SpecializedWidget.Widget2' from external module "tests/cases/compiler/privacyCannotNameAccessorDeclFile_Widgets" but cannot be named.
             return exporter.createExportedWidget2();
         }
         static get myPublicStaticMethod1() { // Error
                    ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS4038: Return type of public static property getter from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
+!!! error TS4038: Return type of public static getter 'myPublicStaticMethod1' from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
             return exporter.createExportedWidget4();
         }
         get myPublicMethod1() { // Error
             ~~~~~~~~~~~~~~~
-!!! error TS4041: Return type of public property getter from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
+!!! error TS4041: Return type of public getter 'myPublicMethod1' from exported class has or is using name 'SpecializedGlobalWidget.Widget4' from external module "GlobalWidgets" but cannot be named.
             return exporter.createExportedWidget4();
         }
     }
diff --git a/tests/baselines/reference/privacyImportParseErrors.errors.txt b/tests/baselines/reference/privacyImportParseErrors.errors.txt
index 1826ac7226a..b607edf049b 100644
--- a/tests/baselines/reference/privacyImportParseErrors.errors.txt
+++ b/tests/baselines/reference/privacyImportParseErrors.errors.txt
@@ -26,14 +26,14 @@ tests/cases/compiler/privacyImportParseErrors.ts(251,40): error TS2307: Cannot f
 tests/cases/compiler/privacyImportParseErrors.ts(252,40): error TS2307: Cannot find module 'glo_M4_private'.
 tests/cases/compiler/privacyImportParseErrors.ts(255,1): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
 tests/cases/compiler/privacyImportParseErrors.ts(255,23): error TS2664: Invalid module name in augmentation, module 'use_glo_M1_public' cannot be found.
-tests/cases/compiler/privacyImportParseErrors.ts(258,45): error TS2304: Cannot find name 'use_glo_M1_public'.
-tests/cases/compiler/privacyImportParseErrors.ts(261,39): error TS2304: Cannot find name 'use_glo_M1_public'.
+tests/cases/compiler/privacyImportParseErrors.ts(258,45): error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
+tests/cases/compiler/privacyImportParseErrors.ts(261,39): error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
 tests/cases/compiler/privacyImportParseErrors.ts(264,40): error TS2307: Cannot find module 'glo_M2_public'.
 tests/cases/compiler/privacyImportParseErrors.ts(273,38): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(277,45): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(284,16): error TS2664: Invalid module name in augmentation, module 'use_glo_M3_private' cannot be found.
-tests/cases/compiler/privacyImportParseErrors.ts(287,46): error TS2304: Cannot find name 'use_glo_M3_private'.
-tests/cases/compiler/privacyImportParseErrors.ts(290,40): error TS2304: Cannot find name 'use_glo_M3_private'.
+tests/cases/compiler/privacyImportParseErrors.ts(287,46): error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
+tests/cases/compiler/privacyImportParseErrors.ts(290,40): error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
 tests/cases/compiler/privacyImportParseErrors.ts(293,41): error TS2307: Cannot find module 'glo_M4_private'.
 tests/cases/compiler/privacyImportParseErrors.ts(302,38): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(306,45): error TS1147: Import declarations in a namespace cannot reference a module.
@@ -371,12 +371,12 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
         export var use_glo_M1_public_v1_public: { new (): use_glo_M1_public.c1; };
         export var use_glo_M1_public_v2_public: use_glo_M1_public;
                                                 ~~~~~~~~~~~~~~~~~
-!!! error TS2304: Cannot find name 'use_glo_M1_public'.
+!!! error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
         export var use_glo_M1_public_v3_public: () => use_glo_M1_public.c1;
         var use_glo_M1_public_v1_private: { new (): use_glo_M1_public.c1; };
         var use_glo_M1_public_v2_private: use_glo_M1_public;
                                           ~~~~~~~~~~~~~~~~~
-!!! error TS2304: Cannot find name 'use_glo_M1_public'.
+!!! error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
         var use_glo_M1_public_v3_private: () => use_glo_M1_public.c1;
     
         import use_glo_M2_public = require("glo_M2_public");
@@ -412,12 +412,12 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
         export var use_glo_M3_private_v1_public: { new (): use_glo_M3_private.c1; };
         export var use_glo_M3_private_v2_public: use_glo_M3_private;
                                                  ~~~~~~~~~~~~~~~~~~
-!!! error TS2304: Cannot find name 'use_glo_M3_private'.
+!!! error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
         export var use_glo_M3_private_v3_public: () => use_glo_M3_private.c1;
         var use_glo_M3_private_v1_private: { new (): use_glo_M3_private.c1; };
         var use_glo_M3_private_v2_private: use_glo_M3_private;
                                            ~~~~~~~~~~~~~~~~~~
-!!! error TS2304: Cannot find name 'use_glo_M3_private'.
+!!! error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
         var use_glo_M3_private_v3_private: () => use_glo_M3_private.c1;
     
         import use_glo_M4_private = require("glo_M4_private");
diff --git a/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt b/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt
index 0237d658da5..73d768ddfeb 100644
--- a/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt
+++ b/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt
@@ -1,8 +1,7 @@
 tests/cases/compiler/promiseEmptyTupleNoException.ts(1,38): error TS1122: A tuple type element list cannot be empty.
 tests/cases/compiler/promiseEmptyTupleNoException.ts(3,3): error TS2322: Type 'any[]' is not assignable to type '[]'.
-  Types of property 'pop' are incompatible.
-    Type '() => any' is not assignable to type '() => never'.
-      Type 'any' is not assignable to type 'never'.
+  Types of property 'length' are incompatible.
+    Type 'number' is not assignable to type '0'.
 
 
 ==== tests/cases/compiler/promiseEmptyTupleNoException.ts (2 errors) ====
@@ -13,8 +12,7 @@ tests/cases/compiler/promiseEmptyTupleNoException.ts(3,3): error TS2322: Type 'a
       return emails;
       ~~~~~~~~~~~~~~
 !!! error TS2322: Type 'any[]' is not assignable to type '[]'.
-!!! error TS2322:   Types of property 'pop' are incompatible.
-!!! error TS2322:     Type '() => any' is not assignable to type '() => never'.
-!!! error TS2322:       Type 'any' is not assignable to type 'never'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type 'number' is not assignable to type '0'.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/quickInfoDisplayPartsInterfaceMembers.baseline b/tests/baselines/reference/quickInfoDisplayPartsInterfaceMembers.baseline
index 732582d9190..fa1e5977dd5 100644
--- a/tests/baselines/reference/quickInfoDisplayPartsInterfaceMembers.baseline
+++ b/tests/baselines/reference/quickInfoDisplayPartsInterfaceMembers.baseline
@@ -368,6 +368,10 @@
           "text": "I",
           "kind": "interfaceName"
         },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "(",
           "kind": "punctuation"
@@ -472,6 +476,14 @@
           "text": " ",
           "kind": "space"
         },
+        {
+          "text": "I",
+          "kind": "interfaceName"
+        },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "new",
           "kind": "keyword"
@@ -480,10 +492,6 @@
           "text": " ",
           "kind": "space"
         },
-        {
-          "text": "I",
-          "kind": "interfaceName"
-        },
         {
           "text": "(",
           "kind": "punctuation"
diff --git a/tests/baselines/reference/quickInfoDisplayPartsTypeParameterInInterface.baseline b/tests/baselines/reference/quickInfoDisplayPartsTypeParameterInInterface.baseline
index d48bb70f8ff..80da1f19ef9 100644
--- a/tests/baselines/reference/quickInfoDisplayPartsTypeParameterInInterface.baseline
+++ b/tests/baselines/reference/quickInfoDisplayPartsTypeParameterInInterface.baseline
@@ -2058,6 +2058,14 @@
           "text": " ",
           "kind": "space"
         },
+        {
+          "text": "I",
+          "kind": "interfaceName"
+        },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "new",
           "kind": "keyword"
@@ -2066,10 +2074,6 @@
           "text": " ",
           "kind": "space"
         },
-        {
-          "text": "I",
-          "kind": "interfaceName"
-        },
         {
           "text": "<",
           "kind": "punctuation"
@@ -2188,6 +2192,10 @@
           "text": "I",
           "kind": "interfaceName"
         },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "<",
           "kind": "punctuation"
@@ -5462,6 +5470,14 @@
           "text": " ",
           "kind": "space"
         },
+        {
+          "text": "I1",
+          "kind": "interfaceName"
+        },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "new",
           "kind": "keyword"
@@ -5470,10 +5486,6 @@
           "text": " ",
           "kind": "space"
         },
-        {
-          "text": "I1",
-          "kind": "interfaceName"
-        },
         {
           "text": "<",
           "kind": "punctuation"
@@ -5748,6 +5760,10 @@
           "text": "I1",
           "kind": "interfaceName"
         },
+        {
+          "text": "\n",
+          "kind": "lineBreak"
+        },
         {
           "text": "<",
           "kind": "punctuation"
diff --git a/tests/baselines/reference/quickInfoJsDocTags.baseline b/tests/baselines/reference/quickInfoJsDocTags.baseline
new file mode 100644
index 00000000000..ba225209760
--- /dev/null
+++ b/tests/baselines/reference/quickInfoJsDocTags.baseline
@@ -0,0 +1,102 @@
+[
+  {
+    "marker": {
+      "fileName": "/tests/cases/fourslash/quickInfoJsDocTags.ts",
+      "position": 258
+    },
+    "quickInfo": {
+      "kind": "function",
+      "kindModifiers": "",
+      "textSpan": {
+        "start": 258,
+        "length": 3
+      },
+      "displayParts": [
+        {
+          "text": "function",
+          "kind": "keyword"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
+        {
+          "text": "foo",
+          "kind": "functionName"
+        },
+        {
+          "text": "(",
+          "kind": "punctuation"
+        },
+        {
+          "text": "x",
+          "kind": "parameterName"
+        },
+        {
+          "text": ":",
+          "kind": "punctuation"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
+        {
+          "text": "any",
+          "kind": "keyword"
+        },
+        {
+          "text": ")",
+          "kind": "punctuation"
+        },
+        {
+          "text": ":",
+          "kind": "punctuation"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
+        {
+          "text": "void",
+          "kind": "keyword"
+        }
+      ],
+      "documentation": [
+        {
+          "text": "Doc{T} A template",
+          "kind": "text"
+        }
+      ],
+      "tags": [
+        {
+          "name": "author",
+          "text": "Me"
+        },
+        {
+          "name": "augments",
+          "text": "C<T> Augments it"
+        },
+        {
+          "name": "type",
+          "text": "{number | string} A type"
+        },
+        {
+          "name": "typedef",
+          "text": "NumOrStr "
+        },
+        {
+          "name": "property",
+          "text": "{number} x The prop"
+        },
+        {
+          "name": "param",
+          "text": "x The param"
+        },
+        {
+          "name": "returns",
+          "text": "The result"
+        }
+      ]
+    }
+  }
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.js b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.js
new file mode 100644
index 00000000000..ae3ce21ff49
--- /dev/null
+++ b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.js
@@ -0,0 +1,72 @@
+//// [tests/cases/compiler/reexportWrittenCorrectlyInDeclaration.ts] ////
+
+//// [ThingA.ts]
+// https://github.com/Microsoft/TypeScript/issues/8612
+export class ThingA { } 
+
+//// [ThingB.ts]
+export class ThingB { }
+
+//// [Things.ts]
+export {ThingA} from "./ThingA";
+export {ThingB} from "./ThingB";
+
+//// [Test.ts]
+import * as things from "./Things";
+
+export class Test {
+    public method = (input: things.ThingA)  => { };
+}
+
+//// [ThingA.js]
+"use strict";
+exports.__esModule = true;
+// https://github.com/Microsoft/TypeScript/issues/8612
+var ThingA = /** @class */ (function () {
+    function ThingA() {
+    }
+    return ThingA;
+}());
+exports.ThingA = ThingA;
+//// [ThingB.js]
+"use strict";
+exports.__esModule = true;
+var ThingB = /** @class */ (function () {
+    function ThingB() {
+    }
+    return ThingB;
+}());
+exports.ThingB = ThingB;
+//// [Things.js]
+"use strict";
+exports.__esModule = true;
+var ThingA_1 = require("./ThingA");
+exports.ThingA = ThingA_1.ThingA;
+var ThingB_1 = require("./ThingB");
+exports.ThingB = ThingB_1.ThingB;
+//// [Test.js]
+"use strict";
+exports.__esModule = true;
+var Test = /** @class */ (function () {
+    function Test() {
+        this.method = function (input) { };
+    }
+    return Test;
+}());
+exports.Test = Test;
+
+
+//// [ThingA.d.ts]
+export declare class ThingA {
+}
+//// [ThingB.d.ts]
+export declare class ThingB {
+}
+//// [Things.d.ts]
+export { ThingA } from "./ThingA";
+export { ThingB } from "./ThingB";
+//// [Test.d.ts]
+import * as things from "./Things";
+export declare class Test {
+    method: (input: things.ThingA) => void;
+}
diff --git a/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.symbols b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.symbols
new file mode 100644
index 00000000000..347ff41cc71
--- /dev/null
+++ b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.symbols
@@ -0,0 +1,29 @@
+=== tests/cases/compiler/ThingA.ts ===
+// https://github.com/Microsoft/TypeScript/issues/8612
+export class ThingA { } 
+>ThingA : Symbol(ThingA, Decl(ThingA.ts, 0, 0))
+
+=== tests/cases/compiler/ThingB.ts ===
+export class ThingB { }
+>ThingB : Symbol(ThingB, Decl(ThingB.ts, 0, 0))
+
+=== tests/cases/compiler/Things.ts ===
+export {ThingA} from "./ThingA";
+>ThingA : Symbol(ThingA, Decl(Things.ts, 0, 8))
+
+export {ThingB} from "./ThingB";
+>ThingB : Symbol(ThingB, Decl(Things.ts, 1, 8))
+
+=== tests/cases/compiler/Test.ts ===
+import * as things from "./Things";
+>things : Symbol(things, Decl(Test.ts, 0, 6))
+
+export class Test {
+>Test : Symbol(Test, Decl(Test.ts, 0, 35))
+
+    public method = (input: things.ThingA)  => { };
+>method : Symbol(Test.method, Decl(Test.ts, 2, 19))
+>input : Symbol(input, Decl(Test.ts, 3, 21))
+>things : Symbol(things, Decl(Test.ts, 0, 6))
+>ThingA : Symbol(things.ThingA, Decl(Things.ts, 0, 8))
+}
diff --git a/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.types b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.types
new file mode 100644
index 00000000000..515ad0f5ac9
--- /dev/null
+++ b/tests/baselines/reference/reexportWrittenCorrectlyInDeclaration.types
@@ -0,0 +1,30 @@
+=== tests/cases/compiler/ThingA.ts ===
+// https://github.com/Microsoft/TypeScript/issues/8612
+export class ThingA { } 
+>ThingA : ThingA
+
+=== tests/cases/compiler/ThingB.ts ===
+export class ThingB { }
+>ThingB : ThingB
+
+=== tests/cases/compiler/Things.ts ===
+export {ThingA} from "./ThingA";
+>ThingA : typeof ThingA
+
+export {ThingB} from "./ThingB";
+>ThingB : typeof ThingB
+
+=== tests/cases/compiler/Test.ts ===
+import * as things from "./Things";
+>things : typeof things
+
+export class Test {
+>Test : Test
+
+    public method = (input: things.ThingA)  => { };
+>method : (input: things.ThingA) => void
+>(input: things.ThingA)  => { } : (input: things.ThingA) => void
+>input : things.ThingA
+>things : any
+>ThingA : things.ThingA
+}
diff --git a/tests/baselines/reference/sourceMap-Comment1.js b/tests/baselines/reference/sourceMap-Comment1.js
index 071e54b5716..6f1f43cd8e2 100644
--- a/tests/baselines/reference/sourceMap-Comment1.js
+++ b/tests/baselines/reference/sourceMap-Comment1.js
@@ -2,5 +2,5 @@
 // Comment
 
 //// [sourceMap-Comment1.js]
-// Comment 
+// Comment
 //# sourceMappingURL=sourceMap-Comment1.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/sourceMap-Comment1.sourcemap.txt b/tests/baselines/reference/sourceMap-Comment1.sourcemap.txt
index 4d427d1de89..e2f9174a45f 100644
--- a/tests/baselines/reference/sourceMap-Comment1.sourcemap.txt
+++ b/tests/baselines/reference/sourceMap-Comment1.sourcemap.txt
@@ -8,7 +8,7 @@ sources: sourceMap-Comment1.ts
 emittedFile:tests/cases/compiler/sourceMap-Comment1.js
 sourceFile:sourceMap-Comment1.ts
 -------------------------------------------------------------------
->>>// Comment 
+>>>// Comment
 1 >
 2 >^^^^^^^^^^
 3 >          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
diff --git a/tests/baselines/reference/spreadUnion2.errors.txt b/tests/baselines/reference/spreadUnion2.errors.txt
new file mode 100644
index 00000000000..f4f81dadf11
--- /dev/null
+++ b/tests/baselines/reference/spreadUnion2.errors.txt
@@ -0,0 +1,41 @@
+tests/cases/conformance/types/spread/spreadUnion2.ts(5,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o1' has type '{} | { a: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 3:4, but here has type '{}'.
+tests/cases/conformance/types/spread/spreadUnion2.ts(8,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o2' has type '{} | { b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 6:4, but here has type '{}'.
+tests/cases/conformance/types/spread/spreadUnion2.ts(11,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o3' has type '{} | { a: number; } | { b: number; } | { a: number; b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 9:4, but here has type '{}'.
+tests/cases/conformance/types/spread/spreadUnion2.ts(12,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o3' has type '{} | { a: number; } | { b: number; } | { a: number; b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 9:4, but here has type '{}'.
+tests/cases/conformance/types/spread/spreadUnion2.ts(15,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o4' has type '{} | { a: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 13:4, but here has type '{}'.
+tests/cases/conformance/types/spread/spreadUnion2.ts(18,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'o5' has type '{} | { b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 16:4, but here has type '{}'.
+
+
+==== tests/cases/conformance/types/spread/spreadUnion2.ts (6 errors) ====
+    declare const undefinedUnion: { a: number } | undefined;
+    declare const nullUnion: { b: number } | null;
+    
+    var o1: {} | { a: number };
+    var o1 = { ...undefinedUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o1' has type '{} | { a: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 3:4, but here has type '{}'.
+    
+    var o2: {} | { b: number };
+    var o2 = { ...nullUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o2' has type '{} | { b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 6:4, but here has type '{}'.
+    
+    var o3: {} | { a: number } | { b: number } | { a: number, b: number };
+    var o3 = { ...undefinedUnion, ...nullUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o3' has type '{} | { a: number; } | { b: number; } | { a: number; b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 9:4, but here has type '{}'.
+    var o3 = { ...nullUnion, ...undefinedUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o3' has type '{} | { a: number; } | { b: number; } | { a: number; b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 9:4, but here has type '{}'.
+    
+    var o4: {} | { a: number };
+    var o4 = { ...undefinedUnion, ...undefinedUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o4' has type '{} | { a: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 13:4, but here has type '{}'.
+    
+    var o5: {} | { b: number };
+    var o5 = { ...nullUnion, ...nullUnion };
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'o5' has type '{} | { b: number; }' at tests/cases/conformance/types/spread/spreadUnion2.ts 16:4, but here has type '{}'.
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/spreadUnion3.errors.txt b/tests/baselines/reference/spreadUnion3.errors.txt
index b7c59697946..b1fa3316d34 100644
--- a/tests/baselines/reference/spreadUnion3.errors.txt
+++ b/tests/baselines/reference/spreadUnion3.errors.txt
@@ -2,8 +2,7 @@ tests/cases/conformance/types/spread/spreadUnion3.ts(2,5): error TS2322: Type '{
   Type '{ y: number; }' is not assignable to type '{ y: string; }'.
     Types of property 'y' are incompatible.
       Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/spread/spreadUnion3.ts(9,23): error TS2339: Property 'a' does not exist on type '{} | {} | { a: number; }'.
-  Property 'a' does not exist on type '{}'.
+tests/cases/conformance/types/spread/spreadUnion3.ts(9,23): error TS2339: Property 'a' does not exist on type '{}'.
 tests/cases/conformance/types/spread/spreadUnion3.ts(17,11): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/spreadUnion3.ts(18,11): error TS2698: Spread types may only be created from object types.
 
@@ -24,8 +23,7 @@ tests/cases/conformance/types/spread/spreadUnion3.ts(18,11): error TS2698: Sprea
         let b = { ...t };
         let c: number = b.a;  // might not have 'a'
                           ~
-!!! error TS2339: Property 'a' does not exist on type '{} | {} | { a: number; }'.
-!!! error TS2339:   Property 'a' does not exist on type '{}'.
+!!! error TS2339: Property 'a' does not exist on type '{}'.
     }
     g()
     g(undefined)
diff --git a/tests/baselines/reference/spreadUnion3.types b/tests/baselines/reference/spreadUnion3.types
index a457307aad1..940ec96f5b7 100644
--- a/tests/baselines/reference/spreadUnion3.types
+++ b/tests/baselines/reference/spreadUnion3.types
@@ -24,14 +24,14 @@ function g(t?: { a: number } | null): void {
 >null : null
 
     let b = { ...t };
->b : {} | {} | { a: number; }
+>b : {}
 >{ ...t } : {} | {} | { a: number; }
 >t : { a: number; } | null | undefined
 
     let c: number = b.a;  // might not have 'a'
 >c : number
 >b.a : any
->b : {} | {} | { a: number; }
+>b : {}
 >a : any
 }
 g()
diff --git a/tests/baselines/reference/staticInstanceResolution5.errors.txt b/tests/baselines/reference/staticInstanceResolution5.errors.txt
index f36851b2b97..b2875e22bda 100644
--- a/tests/baselines/reference/staticInstanceResolution5.errors.txt
+++ b/tests/baselines/reference/staticInstanceResolution5.errors.txt
@@ -1,6 +1,6 @@
-tests/cases/compiler/staticInstanceResolution5_1.ts(4,14): error TS2304: Cannot find name 'WinJS'.
-tests/cases/compiler/staticInstanceResolution5_1.ts(5,23): error TS2304: Cannot find name 'WinJS'.
-tests/cases/compiler/staticInstanceResolution5_1.ts(6,16): error TS2304: Cannot find name 'WinJS'.
+tests/cases/compiler/staticInstanceResolution5_1.ts(4,14): error TS2709: Cannot use namespace 'WinJS' as a type.
+tests/cases/compiler/staticInstanceResolution5_1.ts(5,23): error TS2709: Cannot use namespace 'WinJS' as a type.
+tests/cases/compiler/staticInstanceResolution5_1.ts(6,16): error TS2709: Cannot use namespace 'WinJS' as a type.
 
 
 ==== tests/cases/compiler/staticInstanceResolution5_1.ts (3 errors) ====
@@ -9,13 +9,13 @@ tests/cases/compiler/staticInstanceResolution5_1.ts(6,16): error TS2304: Cannot
     // these 3 should be errors
     var x = (w1: WinJS) => { };
                  ~~~~~
-!!! error TS2304: Cannot find name 'WinJS'.
+!!! error TS2709: Cannot use namespace 'WinJS' as a type.
     var y = function (w2: WinJS) { }
                           ~~~~~
-!!! error TS2304: Cannot find name 'WinJS'.
+!!! error TS2709: Cannot use namespace 'WinJS' as a type.
     function z(w3: WinJS) { }
                    ~~~~~
-!!! error TS2304: Cannot find name 'WinJS'.
+!!! error TS2709: Cannot use namespace 'WinJS' as a type.
     
 ==== tests/cases/compiler/staticInstanceResolution5_0.ts (0 errors) ====
     export class Promise {
diff --git a/tests/baselines/reference/strictTupleLength.errors.txt b/tests/baselines/reference/strictTupleLength.errors.txt
new file mode 100644
index 00000000000..c31064f6b6b
--- /dev/null
+++ b/tests/baselines/reference/strictTupleLength.errors.txt
@@ -0,0 +1,37 @@
+tests/cases/conformance/types/tuple/strictTupleLength.ts(1,9): error TS1122: A tuple type element list cannot be empty.
+tests/cases/conformance/types/tuple/strictTupleLength.ts(11,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 't1' has type '[number]' at tests/cases/conformance/types/tuple/strictTupleLength.ts 1:4, but here has type '[number, number]'.
+tests/cases/conformance/types/tuple/strictTupleLength.ts(12,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 't2' has type '[number, number]' at tests/cases/conformance/types/tuple/strictTupleLength.ts 2:4, but here has type '[number]'.
+tests/cases/conformance/types/tuple/strictTupleLength.ts(18,1): error TS2322: Type 'number[]' is not assignable to type '[number]'.
+  Property '0' is missing in type 'number[]'.
+
+
+==== tests/cases/conformance/types/tuple/strictTupleLength.ts (4 errors) ====
+    var t0: [];
+            ~~
+!!! error TS1122: A tuple type element list cannot be empty.
+    var t1: [number];
+    var t2: [number, number];
+    var arr: number[];
+    
+    var len0: 0 = t0.length;
+    var len1: 1 = t1.length;
+    var len2: 2 = t2.length;
+    var lena: number = arr.length;
+    
+    var t1 = t2; // error
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 't1' has type '[number]' at tests/cases/conformance/types/tuple/strictTupleLength.ts 1:4, but here has type '[number, number]'.
+    var t2 = t1; // error
+        ~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 't2' has type '[number, number]' at tests/cases/conformance/types/tuple/strictTupleLength.ts 2:4, but here has type '[number]'.
+    
+    type A<T extends any[]> = T['length'];
+    var b: A<[boolean]>;
+    var c: 1 = b;
+    
+    t1 = arr; // error with or without strict
+    ~~
+!!! error TS2322: Type 'number[]' is not assignable to type '[number]'.
+!!! error TS2322:   Property '0' is missing in type 'number[]'.
+    arr = t1; // ok with or without strict
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/strictTupleLength.js b/tests/baselines/reference/strictTupleLength.js
new file mode 100644
index 00000000000..e4ae65f2fde
--- /dev/null
+++ b/tests/baselines/reference/strictTupleLength.js
@@ -0,0 +1,37 @@
+//// [strictTupleLength.ts]
+var t0: [];
+var t1: [number];
+var t2: [number, number];
+var arr: number[];
+
+var len0: 0 = t0.length;
+var len1: 1 = t1.length;
+var len2: 2 = t2.length;
+var lena: number = arr.length;
+
+var t1 = t2; // error
+var t2 = t1; // error
+
+type A<T extends any[]> = T['length'];
+var b: A<[boolean]>;
+var c: 1 = b;
+
+t1 = arr; // error with or without strict
+arr = t1; // ok with or without strict
+
+
+//// [strictTupleLength.js]
+var t0;
+var t1;
+var t2;
+var arr;
+var len0 = t0.length;
+var len1 = t1.length;
+var len2 = t2.length;
+var lena = arr.length;
+var t1 = t2; // error
+var t2 = t1; // error
+var b;
+var c = b;
+t1 = arr; // error with or without strict
+arr = t1; // ok with or without strict
diff --git a/tests/baselines/reference/strictTupleLength.symbols b/tests/baselines/reference/strictTupleLength.symbols
new file mode 100644
index 00000000000..e81697b84bf
--- /dev/null
+++ b/tests/baselines/reference/strictTupleLength.symbols
@@ -0,0 +1,66 @@
+=== tests/cases/conformance/types/tuple/strictTupleLength.ts ===
+var t0: [];
+>t0 : Symbol(t0, Decl(strictTupleLength.ts, 0, 3))
+
+var t1: [number];
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+
+var t2: [number, number];
+>t2 : Symbol(t2, Decl(strictTupleLength.ts, 2, 3), Decl(strictTupleLength.ts, 11, 3))
+
+var arr: number[];
+>arr : Symbol(arr, Decl(strictTupleLength.ts, 3, 3))
+
+var len0: 0 = t0.length;
+>len0 : Symbol(len0, Decl(strictTupleLength.ts, 5, 3))
+>t0.length : Symbol(length)
+>t0 : Symbol(t0, Decl(strictTupleLength.ts, 0, 3))
+>length : Symbol(length)
+
+var len1: 1 = t1.length;
+>len1 : Symbol(len1, Decl(strictTupleLength.ts, 6, 3))
+>t1.length : Symbol(length)
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+>length : Symbol(length)
+
+var len2: 2 = t2.length;
+>len2 : Symbol(len2, Decl(strictTupleLength.ts, 7, 3))
+>t2.length : Symbol(length)
+>t2 : Symbol(t2, Decl(strictTupleLength.ts, 2, 3), Decl(strictTupleLength.ts, 11, 3))
+>length : Symbol(length)
+
+var lena: number = arr.length;
+>lena : Symbol(lena, Decl(strictTupleLength.ts, 8, 3))
+>arr.length : Symbol(Array.length, Decl(lib.d.ts, --, --))
+>arr : Symbol(arr, Decl(strictTupleLength.ts, 3, 3))
+>length : Symbol(Array.length, Decl(lib.d.ts, --, --))
+
+var t1 = t2; // error
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+>t2 : Symbol(t2, Decl(strictTupleLength.ts, 2, 3), Decl(strictTupleLength.ts, 11, 3))
+
+var t2 = t1; // error
+>t2 : Symbol(t2, Decl(strictTupleLength.ts, 2, 3), Decl(strictTupleLength.ts, 11, 3))
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+
+type A<T extends any[]> = T['length'];
+>A : Symbol(A, Decl(strictTupleLength.ts, 11, 12))
+>T : Symbol(T, Decl(strictTupleLength.ts, 13, 7))
+>T : Symbol(T, Decl(strictTupleLength.ts, 13, 7))
+
+var b: A<[boolean]>;
+>b : Symbol(b, Decl(strictTupleLength.ts, 14, 3))
+>A : Symbol(A, Decl(strictTupleLength.ts, 11, 12))
+
+var c: 1 = b;
+>c : Symbol(c, Decl(strictTupleLength.ts, 15, 3))
+>b : Symbol(b, Decl(strictTupleLength.ts, 14, 3))
+
+t1 = arr; // error with or without strict
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+>arr : Symbol(arr, Decl(strictTupleLength.ts, 3, 3))
+
+arr = t1; // ok with or without strict
+>arr : Symbol(arr, Decl(strictTupleLength.ts, 3, 3))
+>t1 : Symbol(t1, Decl(strictTupleLength.ts, 1, 3), Decl(strictTupleLength.ts, 10, 3))
+
diff --git a/tests/baselines/reference/strictTupleLength.types b/tests/baselines/reference/strictTupleLength.types
new file mode 100644
index 00000000000..917c2f7db23
--- /dev/null
+++ b/tests/baselines/reference/strictTupleLength.types
@@ -0,0 +1,68 @@
+=== tests/cases/conformance/types/tuple/strictTupleLength.ts ===
+var t0: [];
+>t0 : []
+
+var t1: [number];
+>t1 : [number]
+
+var t2: [number, number];
+>t2 : [number, number]
+
+var arr: number[];
+>arr : number[]
+
+var len0: 0 = t0.length;
+>len0 : 0
+>t0.length : 0
+>t0 : []
+>length : 0
+
+var len1: 1 = t1.length;
+>len1 : 1
+>t1.length : 1
+>t1 : [number]
+>length : 1
+
+var len2: 2 = t2.length;
+>len2 : 2
+>t2.length : 2
+>t2 : [number, number]
+>length : 2
+
+var lena: number = arr.length;
+>lena : number
+>arr.length : number
+>arr : number[]
+>length : number
+
+var t1 = t2; // error
+>t1 : [number]
+>t2 : [number, number]
+
+var t2 = t1; // error
+>t2 : [number, number]
+>t1 : [number]
+
+type A<T extends any[]> = T['length'];
+>A : T["length"]
+>T : T
+>T : T
+
+var b: A<[boolean]>;
+>b : 1
+>A : T["length"]
+
+var c: 1 = b;
+>c : 1
+>b : 1
+
+t1 = arr; // error with or without strict
+>t1 = arr : number[]
+>t1 : [number]
+>arr : number[]
+
+arr = t1; // ok with or without strict
+>arr = t1 : [number]
+>arr : number[]
+>t1 : [number]
+
diff --git a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints2.types b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints2.types
index 23ac78ec013..e2f294343a5 100644
--- a/tests/baselines/reference/subtypesOfTypeParameterWithConstraints2.types
+++ b/tests/baselines/reference/subtypesOfTypeParameterWithConstraints2.types
@@ -676,14 +676,14 @@ function f21<T extends Number>(x: T) {
 
     var r20 = true ? {} : x; // ok
 >r20 : {}
->true ? {} : x : {}
+>true ? {} : x : T | {}
 >true : true
 >{} : {}
 >x : T
 
     var r20 = true ? x : {}; // ok
 >r20 : {}
->true ? x : {} : {}
+>true ? x : {} : T | {}
 >true : true
 >x : T
 >{} : {}
diff --git a/tests/baselines/reference/symbolDeclarationEmit12.errors.txt b/tests/baselines/reference/symbolDeclarationEmit12.errors.txt
index cdc712f698d..3052065ebe6 100644
--- a/tests/baselines/reference/symbolDeclarationEmit12.errors.txt
+++ b/tests/baselines/reference/symbolDeclarationEmit12.errors.txt
@@ -4,7 +4,7 @@ tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(5,33): error TS40
 tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(6,40): error TS4055: Return type of public method from exported class has or is using private name 'I'.
 tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(9,13): error TS2300: Duplicate identifier '[Symbol.toPrimitive]'.
 tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(10,13): error TS2300: Duplicate identifier '[Symbol.toPrimitive]'.
-tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(10,37): error TS4037: Parameter '[Symbol.toPrimitive]' of public property setter from exported class has or is using private name 'I'.
+tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(10,37): error TS4037: Parameter type of public setter '[Symbol.toPrimitive]' from exported class has or is using private name 'I'.
 
 
 ==== tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts (7 errors) ====
@@ -31,6 +31,6 @@ tests/cases/conformance/es6/Symbols/symbolDeclarationEmit12.ts(10,37): error TS4
                 ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2300: Duplicate identifier '[Symbol.toPrimitive]'.
                                         ~
-!!! error TS4037: Parameter '[Symbol.toPrimitive]' of public property setter from exported class has or is using private name 'I'.
+!!! error TS4037: Parameter type of public setter '[Symbol.toPrimitive]' from exported class has or is using private name 'I'.
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/symbolProperty7.js b/tests/baselines/reference/symbolProperty7.js
index 51f3511f332..9dbe5a1abb1 100644
--- a/tests/baselines/reference/symbolProperty7.js
+++ b/tests/baselines/reference/symbolProperty7.js
@@ -11,10 +11,11 @@ class C {
 //// [symbolProperty7.js]
 class C {
     constructor() {
-        this[Symbol()] = 0;
+        this[_a] = 0;
     }
-    [Symbol()]() { }
+    [_a = Symbol(), Symbol(), Symbol()]() { }
     get [Symbol()]() {
         return 0;
     }
 }
+var _a;
diff --git a/tests/baselines/reference/symbolType1.types b/tests/baselines/reference/symbolType1.types
index 5974b9b801c..d55c95d3685 100644
--- a/tests/baselines/reference/symbolType1.types
+++ b/tests/baselines/reference/symbolType1.types
@@ -13,8 +13,8 @@ Symbol instanceof Symbol();
 
 (Symbol() || {}) instanceof Object; // This one should be okay, it's a valid way of distinguishing types
 >(Symbol() || {}) instanceof Object : boolean
->(Symbol() || {}) : {}
->Symbol() || {} : {}
+>(Symbol() || {}) : symbol | {}
+>Symbol() || {} : symbol | {}
 >Symbol() : symbol
 >Symbol : SymbolConstructor
 >{} : {}
@@ -23,8 +23,8 @@ Symbol instanceof Symbol();
 Symbol instanceof (Symbol() || {});
 >Symbol instanceof (Symbol() || {}) : boolean
 >Symbol : SymbolConstructor
->(Symbol() || {}) : {}
->Symbol() || {} : {}
+>(Symbol() || {}) : symbol | {}
+>Symbol() || {} : symbol | {}
 >Symbol() : symbol
 >Symbol : SymbolConstructor
 >{} : {}
diff --git a/tests/baselines/reference/symbolType11.types b/tests/baselines/reference/symbolType11.types
index ec474dcdb54..bbee323b065 100644
--- a/tests/baselines/reference/symbolType11.types
+++ b/tests/baselines/reference/symbolType11.types
@@ -33,7 +33,7 @@ s || 1;
 >1 : 1
 
 ({}) || s;
->({}) || s : {}
+>({}) || s : symbol | {}
 >({}) : {}
 >{} : {}
 >s : symbol
diff --git a/tests/baselines/reference/systemDefaultExportCommentValidity.js b/tests/baselines/reference/systemDefaultExportCommentValidity.js
index a56110b0de9..45fe1df3ccd 100644
--- a/tests/baselines/reference/systemDefaultExportCommentValidity.js
+++ b/tests/baselines/reference/systemDefaultExportCommentValidity.js
@@ -14,7 +14,7 @@ System.register([], function (exports_1, context_1) {
         execute: function () {
             Home = {};
             exports_1("default", Home);
-            // There is intentionally no semicolon on the prior line, this comment should not break emit 
+            // There is intentionally no semicolon on the prior line, this comment should not break emit
         }
     };
 });
diff --git a/tests/baselines/reference/systemModule15.types b/tests/baselines/reference/systemModule15.types
index 747583323ad..ac24678e568 100644
--- a/tests/baselines/reference/systemModule15.types
+++ b/tests/baselines/reference/systemModule15.types
@@ -23,9 +23,9 @@ use(moduleB.moduleC);
 use(moduleB.moduleCStar);
 >use(moduleB.moduleCStar) : void
 >use : (v: any) => void
->moduleB.moduleCStar : typeof "tests/cases/compiler/file3"
+>moduleB.moduleCStar : typeof moduleB.moduleCStar
 >moduleB : typeof moduleB
->moduleCStar : typeof "tests/cases/compiler/file3"
+>moduleCStar : typeof moduleB.moduleCStar
 
 === tests/cases/compiler/file2.ts ===
 import * as moduleCStar from "./file3"
diff --git a/tests/baselines/reference/systemModuleTrailingComments.js b/tests/baselines/reference/systemModuleTrailingComments.js
index 41b0bd299a0..01f17d1facf 100644
--- a/tests/baselines/reference/systemModuleTrailingComments.js
+++ b/tests/baselines/reference/systemModuleTrailingComments.js
@@ -12,7 +12,7 @@ System.register([], function (exports_1, context_1) {
         setters: [],
         execute: function () {
             exports_1("test", test = "TEST");
-            //some comment 
+            //some comment
         }
     };
 });
diff --git a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.errors.txt b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.errors.txt
index 16ad3358038..7e4062ae10a 100644
--- a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.errors.txt
+++ b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.errors.txt
@@ -1,6 +1,5 @@
 tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts(62,36): error TS2345: Argument of type '0' is not assignable to parameter of type '""'.
-tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts(75,79): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-  Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
+tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts(76,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts 74:4, but here has type '{}'.
 
 
 ==== tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts (2 errors) ====
@@ -81,10 +80,9 @@ tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference
     }
     
     var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }`;
-                                                                                  ~~~~~
-!!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
     var a9e: {};
+        ~~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference.ts 74:4, but here has type '{}'.
     
     // Generic tag with multiple parameters of generic type passed arguments with a single best common type
     var a9d = someGenerics9 `${ { x: 3 }}${ { x: 6 }}${ { x: 6 } }`;
diff --git a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.types b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.types
index 5c98fb4e7de..d1be9c77cb9 100644
--- a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.types
+++ b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInference.types
@@ -395,8 +395,8 @@ interface A92 {
 }
 
 var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }`;
->a9e : any
->someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
+>someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 >someGenerics9 : <T>(strs: TemplateStringsArray, a: T, b: T, c: T) => T
 >`${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : string
 >undefined : undefined
@@ -413,7 +413,7 @@ var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y:
 >'' : ""
 
 var a9e: {};
->a9e : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 
 // Generic tag with multiple parameters of generic type passed arguments with a single best common type
 var a9d = someGenerics9 `${ { x: 3 }}${ { x: 6 }}${ { x: 6 } }`;
diff --git a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.errors.txt b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.errors.txt
index 0d43f3d39b2..9112a0542b5 100644
--- a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.errors.txt
+++ b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.errors.txt
@@ -1,6 +1,5 @@
 tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts(62,36): error TS2345: Argument of type '0' is not assignable to parameter of type '""'.
-tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts(75,79): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-  Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
+tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts(76,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts 74:4, but here has type '{}'.
 
 
 ==== tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts (2 errors) ====
@@ -81,10 +80,9 @@ tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInference
     }
     
     var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }`;
-                                                                                  ~~~~~
-!!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
     var a9e: {};
+        ~~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/es6/templates/taggedTemplateStringsTypeArgumentInferenceES6.ts 74:4, but here has type '{}'.
     
     // Generic tag with multiple parameters of generic type passed arguments with a single best common type
     var a9d = someGenerics9 `${ { x: 3 }}${ { x: 6 }}${ { x: 6 } }`;
diff --git a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.types b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.types
index 9f7df761320..e0a1d339376 100644
--- a/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.types
+++ b/tests/baselines/reference/taggedTemplateStringsTypeArgumentInferenceES6.types
@@ -395,8 +395,8 @@ interface A92 {
 }
 
 var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }`;
->a9e : any
->someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
+>someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 >someGenerics9 : <T>(strs: TemplateStringsArray, a: T, b: T, c: T) => T
 >`${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y: '' } }` : string
 >undefined : undefined
@@ -413,7 +413,7 @@ var a9e = someGenerics9 `${ undefined }${ { x: 6, z: new Date() } }${ { x: 6, y:
 >'' : ""
 
 var a9e: {};
->a9e : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 
 // Generic tag with multiple parameters of generic type passed arguments with a single best common type
 var a9d = someGenerics9 `${ { x: 3 }}${ { x: 6 }}${ { x: 6 } }`;
diff --git a/tests/baselines/reference/textChanges/extractMethodLike.js b/tests/baselines/reference/textChanges/extractMethodLike.js
index fa1d625dc4d..a566f76b8ed 100644
--- a/tests/baselines/reference/textChanges/extractMethodLike.js
+++ b/tests/baselines/reference/textChanges/extractMethodLike.js
@@ -1,8 +1,8 @@
 ===ORIGINAL===
 
-namespace M 
+namespace M
 {
-    namespace M2 
+    namespace M2
     {
         function foo() {
             // comment 1
@@ -22,7 +22,7 @@ namespace M
 }
 ===MODIFIED===
 
-namespace M 
+namespace M
 {
     function bar(): any
     {
@@ -37,7 +37,7 @@ namespace M
         const y = 2; // comment 3
         return 1;
     }
-    namespace M2 
+    namespace M2
     {
         function foo() {
             // comment 1
diff --git a/tests/baselines/reference/textChanges/insertNodeInListAfter6.js b/tests/baselines/reference/textChanges/insertNodeInListAfter6.js
index 06eae7372a9..4cffc3f1244 100644
--- a/tests/baselines/reference/textChanges/insertNodeInListAfter6.js
+++ b/tests/baselines/reference/textChanges/insertNodeInListAfter6.js
@@ -1,9 +1,9 @@
 ===ORIGINAL===
 
-const x = 1, 
+const x = 1,
     y = 2;
 ===MODIFIED===
 
-const x = 1, 
-    z = 1, 
+const x = 1,
+    z = 1,
     y = 2;
\ No newline at end of file
diff --git a/tests/baselines/reference/textChanges/insertNodeInListAfter7.js b/tests/baselines/reference/textChanges/insertNodeInListAfter7.js
index bef01503683..afc1d97e155 100644
--- a/tests/baselines/reference/textChanges/insertNodeInListAfter7.js
+++ b/tests/baselines/reference/textChanges/insertNodeInListAfter7.js
@@ -1,9 +1,9 @@
 ===ORIGINAL===
 
-const x = 1, 
+const x = 1,
     y = 2;
 ===MODIFIED===
 
-const x = 1, 
+const x = 1,
     y = 2,
     z = 1;
\ No newline at end of file
diff --git a/tests/baselines/reference/textChanges/insertNodeInListAfter8.js b/tests/baselines/reference/textChanges/insertNodeInListAfter8.js
index e3c44b14274..fd325a4469a 100644
--- a/tests/baselines/reference/textChanges/insertNodeInListAfter8.js
+++ b/tests/baselines/reference/textChanges/insertNodeInListAfter8.js
@@ -1,9 +1,9 @@
 ===ORIGINAL===
 
-const /*x*/ x = 1, 
+const /*x*/ x = 1,
     /*y*/ y = 2;
 ===MODIFIED===
 
-const /*x*/ x = 1, 
-    z = 1, 
+const /*x*/ x = 1,
+    z = 1,
     /*y*/ y = 2;
\ No newline at end of file
diff --git a/tests/baselines/reference/textChanges/insertNodeInListAfter9.js b/tests/baselines/reference/textChanges/insertNodeInListAfter9.js
index 510984b7574..951fcea64bf 100644
--- a/tests/baselines/reference/textChanges/insertNodeInListAfter9.js
+++ b/tests/baselines/reference/textChanges/insertNodeInListAfter9.js
@@ -1,9 +1,9 @@
 ===ORIGINAL===
 
-const /*x*/ x = 1, 
+const /*x*/ x = 1,
     /*y*/ y = 2;
 ===MODIFIED===
 
-const /*x*/ x = 1, 
+const /*x*/ x = 1,
     /*y*/ y = 2,
     z = 1;
\ No newline at end of file
diff --git a/tests/baselines/reference/transformApi/transformsCorrectly.transformAddImportStar.js b/tests/baselines/reference/transformApi/transformsCorrectly.transformAddImportStar.js
new file mode 100644
index 00000000000..167e8eaee09
--- /dev/null
+++ b/tests/baselines/reference/transformApi/transformsCorrectly.transformAddImportStar.js
@@ -0,0 +1,13 @@
+System.register(["./comp1"], function (exports_1, context_1) {
+    var __moduleName = context_1 && context_1.id;
+    var i0;
+    return {
+        setters: [
+            function (i0_1) {
+                i0 = i0_1;
+            }
+        ],
+        execute: function () {
+        }
+    };
+});
diff --git a/tests/baselines/reference/transformApi/transformsCorrectly.transformTypesInExportDefault.js b/tests/baselines/reference/transformApi/transformsCorrectly.transformTypesInExportDefault.js
new file mode 100644
index 00000000000..82fd539be17
--- /dev/null
+++ b/tests/baselines/reference/transformApi/transformsCorrectly.transformTypesInExportDefault.js
@@ -0,0 +1 @@
+export default (foo) => { return 2; };
diff --git a/tests/baselines/reference/transpile/Supports setting strictTuples.js b/tests/baselines/reference/transpile/Supports setting strictTuples.js
new file mode 100644
index 00000000000..8394371f908
--- /dev/null
+++ b/tests/baselines/reference/transpile/Supports setting strictTuples.js	
@@ -0,0 +1,2 @@
+x;
+//# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/transpile/Supports setting strictTuples.oldTranspile.js b/tests/baselines/reference/transpile/Supports setting strictTuples.oldTranspile.js
new file mode 100644
index 00000000000..8394371f908
--- /dev/null
+++ b/tests/baselines/reference/transpile/Supports setting strictTuples.oldTranspile.js	
@@ -0,0 +1,2 @@
+x;
+//# sourceMappingURL=input.js.map
\ No newline at end of file
diff --git a/tests/baselines/reference/tsxFragmentErrors.errors.txt b/tests/baselines/reference/tsxFragmentErrors.errors.txt
new file mode 100644
index 00000000000..03397452abc
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentErrors.errors.txt
@@ -0,0 +1,25 @@
+tests/cases/conformance/jsx/file.tsx(9,7): error TS17015: Expected corresponding closing tag for JSX fragment.
+tests/cases/conformance/jsx/file.tsx(9,11): error TS17014: JSX fragment has no corresponding closing tag.
+tests/cases/conformance/jsx/file.tsx(11,17): error TS1005: '</' expected.
+
+
+==== tests/cases/conformance/jsx/file.tsx (3 errors) ====
+    declare module JSX {
+    	interface Element { }
+    	interface IntrinsicElements {
+    		[s: string]: any;
+    	}
+    }
+    declare var React: any;
+    
+    <>hi</div> // Error
+          ~~~
+!!! error TS17015: Expected corresponding closing tag for JSX fragment.
+              ~~~~~~~~~
+    
+    
+    <>eof   // Error
+    ~~
+!!! error TS17014: JSX fragment has no corresponding closing tag.
+                    
+!!! error TS1005: '</' expected.
\ No newline at end of file
diff --git a/tests/baselines/reference/tsxFragmentErrors.js b/tests/baselines/reference/tsxFragmentErrors.js
new file mode 100644
index 00000000000..b0b5a622ea7
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentErrors.js
@@ -0,0 +1,17 @@
+//// [file.tsx]
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<>hi</div> // Error
+
+<>eof   // Error
+
+//// [file.js]
+React.createElement(React.Fragment, null, "hi") // Error
+    , // Error
+        React.createElement(React.Fragment, null, "eof   // Error");
diff --git a/tests/baselines/reference/tsxFragmentErrors.symbols b/tests/baselines/reference/tsxFragmentErrors.symbols
new file mode 100644
index 00000000000..71ab4b139e3
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentErrors.symbols
@@ -0,0 +1,20 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : Symbol(JSX, Decl(file.tsx, 0, 0))
+
+	interface Element { }
+>Element : Symbol(Element, Decl(file.tsx, 0, 20))
+
+	interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(file.tsx, 1, 22))
+
+		[s: string]: any;
+>s : Symbol(s, Decl(file.tsx, 3, 3))
+	}
+}
+declare var React: any;
+>React : Symbol(React, Decl(file.tsx, 6, 11))
+
+<>hi</div> // Error
+
+<>eof   // Error
diff --git a/tests/baselines/reference/tsxFragmentErrors.types b/tests/baselines/reference/tsxFragmentErrors.types
new file mode 100644
index 00000000000..397d06f1138
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentErrors.types
@@ -0,0 +1,24 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : any
+
+	interface Element { }
+>Element : Element
+
+	interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+		[s: string]: any;
+>s : string
+	}
+}
+declare var React: any;
+>React : any
+
+<>hi</div> // Error
+><>hi</div> // Error<>eof   // Error : JSX.Element
+><>hi</div> : JSX.Element
+
+<>eof   // Error
+><>eof   // Error : JSX.Element
+
diff --git a/tests/baselines/reference/tsxFragmentPreserveEmit.js b/tests/baselines/reference/tsxFragmentPreserveEmit.js
new file mode 100644
index 00000000000..5b3328a842d
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentPreserveEmit.js
@@ -0,0 +1,23 @@
+//// [file.tsx]
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+
+//// [file.jsx]
+<></>; // no whitespace
+<></>; // lots of whitespace
+<></>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
diff --git a/tests/baselines/reference/tsxFragmentPreserveEmit.symbols b/tests/baselines/reference/tsxFragmentPreserveEmit.symbols
new file mode 100644
index 00000000000..c75d812480c
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentPreserveEmit.symbols
@@ -0,0 +1,37 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : Symbol(JSX, Decl(file.tsx, 0, 0))
+
+	interface Element { }
+>Element : Symbol(Element, Decl(file.tsx, 0, 20))
+
+	interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(file.tsx, 1, 22))
+
+		[s: string]: any;
+>s : Symbol(s, Decl(file.tsx, 3, 3))
+	}
+}
+declare var React: any;
+>React : Symbol(React, Decl(file.tsx, 6, 11))
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>div : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>div : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+
diff --git a/tests/baselines/reference/tsxFragmentPreserveEmit.types b/tests/baselines/reference/tsxFragmentPreserveEmit.types
new file mode 100644
index 00000000000..4eea3d72cff
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentPreserveEmit.types
@@ -0,0 +1,54 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : any
+
+	interface Element { }
+>Element : Element
+
+	interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+		[s: string]: any;
+>s : string
+	}
+}
+declare var React: any;
+>React : any
+
+<></>; // no whitespace
+><></> : JSX.Element
+
+<    ></   >; // lots of whitespace
+><    ></   > : JSX.Element
+
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+>< /*starting wrap*/ ></ /*ending wrap*/> : JSX.Element
+
+<>hi</>; // text inside
+><>hi</> : JSX.Element
+
+<><span>hi</span><div>bye</div></>; // children
+><><span>hi</span><div>bye</div></> : JSX.Element
+><span>hi</span> : JSX.Element
+>span : any
+>span : any
+><div>bye</div> : JSX.Element
+>div : any
+>div : any
+
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+><><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></> : JSX.Element
+><span>1</span> : JSX.Element
+>span : any
+>span : any
+><><span>2.1</span><span>2.2</span></> : JSX.Element
+><span>2.1</span> : JSX.Element
+>span : any
+>span : any
+><span>2.2</span> : JSX.Element
+>span : any
+>span : any
+><span>3</span> : JSX.Element
+>span : any
+>span : any
+
diff --git a/tests/baselines/reference/tsxFragmentReactEmit.js b/tests/baselines/reference/tsxFragmentReactEmit.js
new file mode 100644
index 00000000000..137d07db33c
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentReactEmit.js
@@ -0,0 +1,30 @@
+//// [file.tsx]
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+
+//// [file.js]
+React.createElement(React.Fragment, null); // no whitespace
+React.createElement(React.Fragment, null); // lots of whitespace
+React.createElement(React.Fragment, null); // comments in the tags
+React.createElement(React.Fragment, null, "hi"); // text inside
+React.createElement(React.Fragment, null,
+    React.createElement("span", null, "hi"),
+    React.createElement("div", null, "bye")); // children
+React.createElement(React.Fragment, null,
+    React.createElement("span", null, "1"),
+    React.createElement(React.Fragment, null,
+        React.createElement("span", null, "2.1"),
+        React.createElement("span", null, "2.2")),
+    React.createElement("span", null, "3")); // nested fragments
diff --git a/tests/baselines/reference/tsxFragmentReactEmit.symbols b/tests/baselines/reference/tsxFragmentReactEmit.symbols
new file mode 100644
index 00000000000..c75d812480c
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentReactEmit.symbols
@@ -0,0 +1,37 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : Symbol(JSX, Decl(file.tsx, 0, 0))
+
+	interface Element { }
+>Element : Symbol(Element, Decl(file.tsx, 0, 20))
+
+	interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(file.tsx, 1, 22))
+
+		[s: string]: any;
+>s : Symbol(s, Decl(file.tsx, 3, 3))
+	}
+}
+declare var React: any;
+>React : Symbol(React, Decl(file.tsx, 6, 11))
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>div : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>div : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+>span : Symbol(JSX.IntrinsicElements, Decl(file.tsx, 1, 22))
+
diff --git a/tests/baselines/reference/tsxFragmentReactEmit.types b/tests/baselines/reference/tsxFragmentReactEmit.types
new file mode 100644
index 00000000000..4eea3d72cff
--- /dev/null
+++ b/tests/baselines/reference/tsxFragmentReactEmit.types
@@ -0,0 +1,54 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare module JSX {
+>JSX : any
+
+	interface Element { }
+>Element : Element
+
+	interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+		[s: string]: any;
+>s : string
+	}
+}
+declare var React: any;
+>React : any
+
+<></>; // no whitespace
+><></> : JSX.Element
+
+<    ></   >; // lots of whitespace
+><    ></   > : JSX.Element
+
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+>< /*starting wrap*/ ></ /*ending wrap*/> : JSX.Element
+
+<>hi</>; // text inside
+><>hi</> : JSX.Element
+
+<><span>hi</span><div>bye</div></>; // children
+><><span>hi</span><div>bye</div></> : JSX.Element
+><span>hi</span> : JSX.Element
+>span : any
+>span : any
+><div>bye</div> : JSX.Element
+>div : any
+>div : any
+
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
+><><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></> : JSX.Element
+><span>1</span> : JSX.Element
+>span : any
+>span : any
+><><span>2.1</span><span>2.2</span></> : JSX.Element
+><span>2.1</span> : JSX.Element
+>span : any
+>span : any
+><span>2.2</span> : JSX.Element
+>span : any
+>span : any
+><span>3</span> : JSX.Element
+>span : any
+>span : any
+
diff --git a/tests/baselines/reference/tsxStatelessFunctionComponentsWithTypeArguments4.errors.txt b/tests/baselines/reference/tsxStatelessFunctionComponentsWithTypeArguments4.errors.txt
index 2feed16ac0a..d692364d264 100644
--- a/tests/baselines/reference/tsxStatelessFunctionComponentsWithTypeArguments4.errors.txt
+++ b/tests/baselines/reference/tsxStatelessFunctionComponentsWithTypeArguments4.errors.txt
@@ -1,9 +1,9 @@
 tests/cases/conformance/jsx/file.tsx(9,33): error TS2322: Type '{ a: number; }' is not assignable to type 'IntrinsicAttributes & { b: {}; a: number; }'.
   Type '{ a: number; }' is not assignable to type '{ b: {}; a: number; }'.
     Property 'b' is missing in type '{ a: number; }'.
-tests/cases/conformance/jsx/file.tsx(10,33): error TS2322: Type 'T' is not assignable to type 'IntrinsicAttributes & { b: number; a: {}; }'.
-  Type '{ b: number; }' is not assignable to type 'IntrinsicAttributes & { b: number; a: {}; }'.
-    Type '{ b: number; }' is not assignable to type '{ b: number; a: {}; }'.
+tests/cases/conformance/jsx/file.tsx(10,33): error TS2322: Type 'T' is not assignable to type 'IntrinsicAttributes & { b: {}; a: {}; }'.
+  Type '{ b: number; }' is not assignable to type 'IntrinsicAttributes & { b: {}; a: {}; }'.
+    Type '{ b: number; }' is not assignable to type '{ b: {}; a: {}; }'.
       Property 'a' is missing in type '{ b: number; }'.
         Type 'T' is not assignable to type 'IntrinsicAttributes'.
           Type '{ b: number; }' has no properties in common with type 'IntrinsicAttributes'.
@@ -25,9 +25,9 @@ tests/cases/conformance/jsx/file.tsx(10,33): error TS2322: Type 'T' is not assig
 !!! error TS2322:     Property 'b' is missing in type '{ a: number; }'.
         let a2 = <OverloadComponent {...arg1} ignore-prop />  // missing a
                                     ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2322: Type 'T' is not assignable to type 'IntrinsicAttributes & { b: number; a: {}; }'.
-!!! error TS2322:   Type '{ b: number; }' is not assignable to type 'IntrinsicAttributes & { b: number; a: {}; }'.
-!!! error TS2322:     Type '{ b: number; }' is not assignable to type '{ b: number; a: {}; }'.
+!!! error TS2322: Type 'T' is not assignable to type 'IntrinsicAttributes & { b: {}; a: {}; }'.
+!!! error TS2322:   Type '{ b: number; }' is not assignable to type 'IntrinsicAttributes & { b: {}; a: {}; }'.
+!!! error TS2322:     Type '{ b: number; }' is not assignable to type '{ b: {}; a: {}; }'.
 !!! error TS2322:       Property 'a' is missing in type '{ b: number; }'.
 !!! error TS2322:         Type 'T' is not assignable to type 'IntrinsicAttributes'.
 !!! error TS2322:           Type '{ b: number; }' has no properties in common with type 'IntrinsicAttributes'.
diff --git a/tests/baselines/reference/tupleTypes.errors.txt b/tests/baselines/reference/tupleTypes.errors.txt
index 3b55476e4b1..16a8f66ba79 100644
--- a/tests/baselines/reference/tupleTypes.errors.txt
+++ b/tests/baselines/reference/tupleTypes.errors.txt
@@ -5,6 +5,9 @@ tests/cases/compiler/tupleTypes.ts(15,1): error TS2322: Type '[number]' is not a
   Property '1' is missing in type '[number]'.
 tests/cases/compiler/tupleTypes.ts(17,1): error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
   Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/tupleTypes.ts(18,1): error TS2322: Type '[number, string, number]' is not assignable to type '[number, string]'.
+  Types of property 'length' are incompatible.
+    Type '3' is not assignable to type '2'.
 tests/cases/compiler/tupleTypes.ts(41,1): error TS2322: Type 'undefined[]' is not assignable to type '[number, string]'.
 tests/cases/compiler/tupleTypes.ts(47,1): error TS2322: Type '[number, string]' is not assignable to type 'number[]'.
   Types of property 'pop' are incompatible.
@@ -22,7 +25,7 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
   Type '{}' is not assignable to type 'string'.
 
 
-==== tests/cases/compiler/tupleTypes.ts (9 errors) ====
+==== tests/cases/compiler/tupleTypes.ts (10 errors) ====
     var v1: [];  // Error
             ~~
 !!! error TS1122: A tuple type element list cannot be empty.
@@ -51,7 +54,11 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
     ~
 !!! error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
 !!! error TS2322:   Type 'string' is not assignable to type 'number'.
-    t = [1, "hello", 2];  // Ok
+    t = [1, "hello", 2];  // Error
+    ~
+!!! error TS2322: Type '[number, string, number]' is not assignable to type '[number, string]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '3' is not assignable to type '2'.
     
     var tf: [string, (x: string) => number] = ["hello", x => x.length];
     
diff --git a/tests/baselines/reference/tupleTypes.js b/tests/baselines/reference/tupleTypes.js
index 451aeb5eb09..947b7bba30b 100644
--- a/tests/baselines/reference/tupleTypes.js
+++ b/tests/baselines/reference/tupleTypes.js
@@ -16,7 +16,7 @@ t = [];               // Error
 t = [1];              // Error
 t = [1, "hello"];     // Ok
 t = ["hello", 1];     // Error
-t = [1, "hello", 2];  // Ok
+t = [1, "hello", 2];  // Error
 
 var tf: [string, (x: string) => number] = ["hello", x => x.length];
 
@@ -70,7 +70,7 @@ t = []; // Error
 t = [1]; // Error
 t = [1, "hello"]; // Ok
 t = ["hello", 1]; // Error
-t = [1, "hello", 2]; // Ok
+t = [1, "hello", 2]; // Error
 var tf = ["hello", function (x) { return x.length; }];
 var ff1 = ff("hello", ["foo", function (x) { return x.length; }]);
 var ff1;
diff --git a/tests/baselines/reference/tupleTypes.symbols b/tests/baselines/reference/tupleTypes.symbols
index 1f14b269ca9..cf60cea8534 100644
--- a/tests/baselines/reference/tupleTypes.symbols
+++ b/tests/baselines/reference/tupleTypes.symbols
@@ -49,7 +49,7 @@ t = [1, "hello"];     // Ok
 t = ["hello", 1];     // Error
 >t : Symbol(t, Decl(tupleTypes.ts, 5, 3))
 
-t = [1, "hello", 2];  // Ok
+t = [1, "hello", 2];  // Error
 >t : Symbol(t, Decl(tupleTypes.ts, 5, 3))
 
 var tf: [string, (x: string) => number] = ["hello", x => x.length];
diff --git a/tests/baselines/reference/tupleTypes.types b/tests/baselines/reference/tupleTypes.types
index 3bbf48bdb29..3f68d4c7e2d 100644
--- a/tests/baselines/reference/tupleTypes.types
+++ b/tests/baselines/reference/tupleTypes.types
@@ -66,7 +66,7 @@ t = ["hello", 1];     // Error
 >"hello" : "hello"
 >1 : 1
 
-t = [1, "hello", 2];  // Ok
+t = [1, "hello", 2];  // Error
 >t = [1, "hello", 2] : [number, string, number]
 >t : [number, string]
 >[1, "hello", 2] : [number, string, number]
diff --git a/tests/baselines/reference/typeArgInference2.errors.txt b/tests/baselines/reference/typeArgInference2.errors.txt
deleted file mode 100644
index 41fdd9b0783..00000000000
--- a/tests/baselines/reference/typeArgInference2.errors.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-tests/cases/compiler/typeArgInference2.ts(12,52): error TS2345: Argument of type '{ name: string; b: number; }' is not assignable to parameter of type '{ name: string; a: number; }'.
-  Object literal may only specify known properties, and 'b' does not exist in type '{ name: string; a: number; }'.
-
-
-==== tests/cases/compiler/typeArgInference2.ts (1 errors) ====
-    interface Item {
-        name: string;
-    }
-    
-    declare function foo<T extends Item>(x?: T, y?: T): T;
-    
-    var z1 = foo(null);                   // any
-    var z2 = foo();                       // Item
-    var z3 = foo({ name: null });         // { name: any }
-    var z4 = foo({ name: "abc" });        // { name: string }
-    var z5 = foo({ name: "abc", a: 5 });  // { name: string; a: number }
-    var z6 = foo({ name: "abc", a: 5 }, { name: "def", b: 5 });  // error
-                                                       ~~~~
-!!! error TS2345: Argument of type '{ name: string; b: number; }' is not assignable to parameter of type '{ name: string; a: number; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'b' does not exist in type '{ name: string; a: number; }'.
\ No newline at end of file
diff --git a/tests/baselines/reference/typeArgInference2.types b/tests/baselines/reference/typeArgInference2.types
index 12262c1896f..2b985a7c208 100644
--- a/tests/baselines/reference/typeArgInference2.types
+++ b/tests/baselines/reference/typeArgInference2.types
@@ -54,8 +54,8 @@ var z5 = foo({ name: "abc", a: 5 });  // { name: string; a: number }
 >5 : 5
 
 var z6 = foo({ name: "abc", a: 5 }, { name: "def", b: 5 });  // error
->z6 : any
->foo({ name: "abc", a: 5 }, { name: "def", b: 5 }) : any
+>z6 : { name: string; a: number; b?: undefined; } | { name: string; b: number; a?: undefined; }
+>foo({ name: "abc", a: 5 }, { name: "def", b: 5 }) : { name: string; a: number; b?: undefined; } | { name: string; b: number; a?: undefined; }
 >foo : <T extends Item>(x?: T, y?: T) => T
 >{ name: "abc", a: 5 } : { name: string; a: number; }
 >name : string
diff --git a/tests/baselines/reference/typeArgumentInference.errors.txt b/tests/baselines/reference/typeArgumentInference.errors.txt
index 4daa055d20a..cfed6cc640b 100644
--- a/tests/baselines/reference/typeArgumentInference.errors.txt
+++ b/tests/baselines/reference/typeArgumentInference.errors.txt
@@ -1,6 +1,5 @@
 tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts(68,29): error TS2345: Argument of type '0' is not assignable to parameter of type '""'.
-tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts(82,69): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-  Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
+tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts(83,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts 81:4, but here has type '{}'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts(84,74): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type 'A92'.
   Object literal may only specify known properties, and 'y' does not exist in type 'A92'.
 
@@ -90,10 +89,9 @@ tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts(84,74
         z?: Date;
     }
     var a9e = someGenerics9(undefined, { x: 6, z: new Date() }, { x: 6, y: '' });
-                                                                        ~~~~~
-!!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: Date; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: Date; }'.
     var a9e: {};
+        ~~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInference.ts 81:4, but here has type '{}'.
     var a9f = someGenerics9<A92>(undefined, { x: 6, z: new Date() }, { x: 6, y: '' });
                                                                              ~~~~~
 !!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type 'A92'.
diff --git a/tests/baselines/reference/typeArgumentInference.types b/tests/baselines/reference/typeArgumentInference.types
index 02326834d3b..1f39235ae36 100644
--- a/tests/baselines/reference/typeArgumentInference.types
+++ b/tests/baselines/reference/typeArgumentInference.types
@@ -421,8 +421,8 @@ interface A92 {
 >Date : Date
 }
 var a9e = someGenerics9(undefined, { x: 6, z: new Date() }, { x: 6, y: '' });
->a9e : any
->someGenerics9(undefined, { x: 6, z: new Date() }, { x: 6, y: '' }) : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
+>someGenerics9(undefined, { x: 6, z: new Date() }, { x: 6, y: '' }) : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 >someGenerics9 : <T>(a: T, b: T, c: T) => T
 >undefined : undefined
 >{ x: 6, z: new Date() } : { x: number; z: Date; }
@@ -438,7 +438,7 @@ var a9e = someGenerics9(undefined, { x: 6, z: new Date() }, { x: 6, y: '' });
 >'' : ""
 
 var a9e: {};
->a9e : any
+>a9e : { x: number; z: Date; y?: undefined; } | { x: number; y: string; z?: undefined; }
 
 var a9f = someGenerics9<A92>(undefined, { x: 6, z: new Date() }, { x: 6, y: '' });
 >a9f : any
diff --git a/tests/baselines/reference/typeArgumentInferenceConstructSignatures.errors.txt b/tests/baselines/reference/typeArgumentInferenceConstructSignatures.errors.txt
index da5558afdf7..ef0c93f20cd 100644
--- a/tests/baselines/reference/typeArgumentInferenceConstructSignatures.errors.txt
+++ b/tests/baselines/reference/typeArgumentInferenceConstructSignatures.errors.txt
@@ -12,8 +12,7 @@ tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstruct
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(106,33): error TS2345: Argument of type '0' is not assignable to parameter of type '""'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(118,9): error TS2304: Cannot find name 'Window'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(120,51): error TS2304: Cannot find name 'window'.
-tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(120,69): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: any; }'.
-  Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: any; }'.
+tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(121,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts 119:4, but here has type '{}'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(122,56): error TS2304: Cannot find name 'window'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts(122,74): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type 'A92'.
   Object literal may only specify known properties, and 'y' does not exist in type 'A92'.
@@ -162,10 +161,9 @@ tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstruct
     var a9e = new someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
                                                       ~~~~~~
 !!! error TS2304: Cannot find name 'window'.
-                                                                        ~~~~~
-!!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: any; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: any; }'.
     var a9e: {};
+        ~~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceConstructSignatures.ts 119:4, but here has type '{}'.
     var a9f = new someGenerics9<A92>(undefined, { x: 6, z: window }, { x: 6, y: '' });
                                                            ~~~~~~
 !!! error TS2304: Cannot find name 'window'.
diff --git a/tests/baselines/reference/typeArgumentInferenceConstructSignatures.types b/tests/baselines/reference/typeArgumentInferenceConstructSignatures.types
index 8981c077b48..04dae1dafa7 100644
--- a/tests/baselines/reference/typeArgumentInferenceConstructSignatures.types
+++ b/tests/baselines/reference/typeArgumentInferenceConstructSignatures.types
@@ -524,8 +524,8 @@ interface A92 {
 >Window : No type information available!
 }
 var a9e = new someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
->a9e : any
->new someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' }) : any
+>a9e : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
+>new someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' }) : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
 >someGenerics9 : someGenerics9
 >undefined : undefined
 >{ x: 6, z: window } : { x: number; z: any; }
@@ -540,7 +540,7 @@ var a9e = new someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
 >'' : ""
 
 var a9e: {};
->a9e : any
+>a9e : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
 
 var a9f = new someGenerics9<A92>(undefined, { x: 6, z: window }, { x: 6, y: '' });
 >a9f : any
diff --git a/tests/baselines/reference/typeArgumentInferenceWithConstraints.errors.txt b/tests/baselines/reference/typeArgumentInferenceWithConstraints.errors.txt
index 6cc81171bcc..2b305390689 100644
--- a/tests/baselines/reference/typeArgumentInferenceWithConstraints.errors.txt
+++ b/tests/baselines/reference/typeArgumentInferenceWithConstraints.errors.txt
@@ -17,8 +17,7 @@ tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConst
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(73,29): error TS2345: Argument of type '0' is not assignable to parameter of type '""'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(85,9): error TS2304: Cannot find name 'Window'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(87,47): error TS2304: Cannot find name 'window'.
-tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(87,65): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: any; }'.
-  Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: any; }'.
+tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(88,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts 86:4, but here has type '{}'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(89,52): error TS2304: Cannot find name 'window'.
 tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts(89,70): error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type 'A92'.
   Object literal may only specify known properties, and 'y' does not exist in type 'A92'.
@@ -144,10 +143,9 @@ tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConst
     var a9e = someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
                                                   ~~~~~~
 !!! error TS2304: Cannot find name 'window'.
-                                                                    ~~~~~
-!!! error TS2345: Argument of type '{ x: number; y: string; }' is not assignable to parameter of type '{ x: number; z: any; }'.
-!!! error TS2345:   Object literal may only specify known properties, and 'y' does not exist in type '{ x: number; z: any; }'.
     var a9e: {};
+        ~~~
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'a9e' has type '{ x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }' at tests/cases/conformance/expressions/functionCalls/typeArgumentInferenceWithConstraints.ts 86:4, but here has type '{}'.
     var a9f = someGenerics9<A92>(undefined, { x: 6, z: window }, { x: 6, y: '' });
                                                        ~~~~~~
 !!! error TS2304: Cannot find name 'window'.
diff --git a/tests/baselines/reference/typeArgumentInferenceWithConstraints.types b/tests/baselines/reference/typeArgumentInferenceWithConstraints.types
index 4e120b70eb5..4ca65f02b02 100644
--- a/tests/baselines/reference/typeArgumentInferenceWithConstraints.types
+++ b/tests/baselines/reference/typeArgumentInferenceWithConstraints.types
@@ -464,8 +464,8 @@ interface A92 {
 >Window : No type information available!
 }
 var a9e = someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
->a9e : any
->someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' }) : any
+>a9e : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
+>someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' }) : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
 >someGenerics9 : <T extends any>(a: T, b: T, c: T) => T
 >undefined : undefined
 >{ x: 6, z: window } : { x: number; z: any; }
@@ -480,7 +480,7 @@ var a9e = someGenerics9(undefined, { x: 6, z: window }, { x: 6, y: '' });
 >'' : ""
 
 var a9e: {};
->a9e : any
+>a9e : { x: number; z: any; y?: undefined; } | { x: number; y: string; z?: undefined; }
 
 var a9f = someGenerics9<A92>(undefined, { x: 6, z: window }, { x: 6, y: '' });
 >a9f : any
diff --git a/tests/baselines/reference/typeParameterUsedAsTypeParameterConstraint3.js b/tests/baselines/reference/typeParameterUsedAsTypeParameterConstraint3.js
index 95c65d5f3a9..0655ad17138 100644
--- a/tests/baselines/reference/typeParameterUsedAsTypeParameterConstraint3.js
+++ b/tests/baselines/reference/typeParameterUsedAsTypeParameterConstraint3.js
@@ -64,4 +64,4 @@ interface I2<V, T, U> {
 //    y: U;
 //    z: V;
 //    foo<W extends V>(x: W): T;
-//} 
+//}
diff --git a/tests/baselines/reference/typeofInternalModules.errors.txt b/tests/baselines/reference/typeofInternalModules.errors.txt
index 5402249ea63..ca8fe501c94 100644
--- a/tests/baselines/reference/typeofInternalModules.errors.txt
+++ b/tests/baselines/reference/typeofInternalModules.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/typeofInternalModules.ts(15,16): error TS2708: Cannot use namespace 'importUninst' as a value.
-tests/cases/compiler/typeofInternalModules.ts(17,9): error TS2304: Cannot find name 'Outer'.
+tests/cases/compiler/typeofInternalModules.ts(17,9): error TS2709: Cannot use namespace 'Outer' as a type.
 tests/cases/compiler/typeofInternalModules.ts(19,1): error TS2322: Type 'typeof Outer' is not assignable to type 'typeof instantiated'.
   Property 'C' is missing in type 'typeof Outer'.
 tests/cases/compiler/typeofInternalModules.ts(21,16): error TS2708: Cannot use namespace 'importUninst' as a value.
@@ -28,7 +28,7 @@ tests/cases/compiler/typeofInternalModules.ts(23,1): error TS2322: Type 'typeof
     
     var x4: Outer = Outer;
             ~~~~~
-!!! error TS2304: Cannot find name 'Outer'.
+!!! error TS2709: Cannot use namespace 'Outer' as a type.
     var x5: typeof importInst;
     x5 = Outer;
     ~~
diff --git a/tests/baselines/reference/undefinedAssignableToEveryType.js b/tests/baselines/reference/undefinedAssignableToEveryType.js
index 507f647763a..de64f97f70b 100644
--- a/tests/baselines/reference/undefinedAssignableToEveryType.js
+++ b/tests/baselines/reference/undefinedAssignableToEveryType.js
@@ -83,4 +83,4 @@ function foo(x, y, z) {
 //    x = undefined;
 //    y = undefined;
 //    z = undefined;
-//} 
+//}
diff --git a/tests/baselines/reference/unionTypeFromArrayLiteral.errors.txt b/tests/baselines/reference/unionTypeFromArrayLiteral.errors.txt
new file mode 100644
index 00000000000..2ecce8a802e
--- /dev/null
+++ b/tests/baselines/reference/unionTypeFromArrayLiteral.errors.txt
@@ -0,0 +1,33 @@
+tests/cases/conformance/types/union/unionTypeFromArrayLiteral.ts(9,5): error TS2322: Type '[number, string, string]' is not assignable to type '[number, string]'.
+  Types of property 'length' are incompatible.
+    Type '3' is not assignable to type '2'.
+
+
+==== tests/cases/conformance/types/union/unionTypeFromArrayLiteral.ts (1 errors) ====
+    // The resulting type an array literal expression is determined as follows:
+    // If the array literal is empty, the resulting type is an array type with the element type Undefined.
+    // Otherwise, if the array literal is contextually typed by a type that has a property with the numeric name ‘0’, the resulting type is a tuple type constructed from the types of the element expressions.
+    // Otherwise, the resulting type is an array type with an element type that is the union of the types of the element expressions.
+    
+    var arr1 = [1, 2]; // number[]
+    var arr2 = ["hello", true]; // (string | number)[]
+    var arr3Tuple: [number, string] = [3, "three"]; // [number, string]
+    var arr4Tuple: [number, string] = [3, "three", "hello"]; // [number, string, string]
+        ~~~~~~~~~
+!!! error TS2322: Type '[number, string, string]' is not assignable to type '[number, string]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '3' is not assignable to type '2'.
+    var arrEmpty = [];
+    var arr5Tuple: {
+        0: string;
+        5: number;
+    } = ["hello", true, false, " hello", true, 10, "any"]; // Tuple
+    class C { foo() { } }
+    class D { foo2() { } }
+    class E extends C { foo3() { } }
+    class F extends C { foo4() { } }
+    var c: C, d: D, e: E, f: F;
+    var arr6 = [c, d];  // (C | D)[]
+    var arr7 = [c, d, e]; // (C | D)[]
+    var arr8 = [c, e]; // C[]
+    var arr9 = [e, f]; // (E|F)[]
\ No newline at end of file
diff --git a/tests/baselines/reference/user/electron.log b/tests/baselines/reference/user/electron.log
new file mode 100644
index 00000000000..e5eef689d49
--- /dev/null
+++ b/tests/baselines/reference/user/electron.log
@@ -0,0 +1,13 @@
+Exit Code: 2
+Standard output:
+node_modules/electron/electron.d.ts(5390,13): error TS2430: Interface 'WebviewTag' incorrectly extends interface 'HTMLElement'.
+  Types of property 'addEventListener' are incompatible.
+    Type '{ (event: "load-commit", listener: (event: LoadCommitEvent) => void, useCapture?: boolean | undef...' is not assignable to type '{ <K extends "error" | "waiting" | "progress" | "ended" | "change" | "input" | "select" | "abort"...'.
+      Types of parameters 'listener' and 'listener' are incompatible.
+        Type 'EventListenerOrEventListenerObject' is not assignable to type '(event: LoadCommitEvent) => void'.
+          Type 'EventListenerObject' is not assignable to type '(event: LoadCommitEvent) => void'.
+            Type 'EventListenerObject' provides no match for the signature '(event: LoadCommitEvent): void'.
+
+
+
+Standard error:
diff --git a/tests/baselines/reference/user/leveldown.log b/tests/baselines/reference/user/leveldown.log
new file mode 100644
index 00000000000..c37a983f73d
--- /dev/null
+++ b/tests/baselines/reference/user/leveldown.log
@@ -0,0 +1,20 @@
+Exit Code: 2
+Standard output:
+node_modules/abstract-leveldown/index.d.ts(2,3): error TS7010: 'open', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(3,3): error TS7010: 'open', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(5,3): error TS7010: 'close', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(7,3): error TS7010: 'get', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(7,26): error TS7006: Parameter 'err' implicitly has an 'any' type.
+node_modules/abstract-leveldown/index.d.ts(8,3): error TS7010: 'get', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(8,39): error TS7006: Parameter 'err' implicitly has an 'any' type.
+node_modules/abstract-leveldown/index.d.ts(10,3): error TS7010: 'put', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(11,3): error TS7010: 'put', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(13,3): error TS7010: 'del', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(14,3): error TS7010: 'del', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(17,3): error TS7010: 'batch', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/abstract-leveldown/index.d.ts(18,3): error TS7010: 'batch', which lacks return-type annotation, implicitly has an 'any' return type.
+node_modules/leveldown/leveldown.d.ts(66,3): error TS7010: 'seek', which lacks return-type annotation, implicitly has an 'any' return type.
+
+
+
+Standard error:
diff --git a/tests/baselines/reference/user/rxjs.log b/tests/baselines/reference/user/rxjs.log
new file mode 100644
index 00000000000..73058119ce9
--- /dev/null
+++ b/tests/baselines/reference/user/rxjs.log
@@ -0,0 +1,12 @@
+Exit Code: 2
+Standard output:
+node_modules/rxjs/scheduler/VirtualTimeScheduler.d.ts(22,22): error TS2415: Class 'VirtualAction<T>' incorrectly extends base class 'AsyncAction<T>'.
+  Types of property 'work' are incompatible.
+    Type '(this: VirtualAction<T>, state?: T | undefined) => void' is not assignable to type '(this: AsyncAction<T>, state?: T | undefined) => void'.
+      The 'this' types of each signature are incompatible.
+        Type 'AsyncAction<T>' is not assignable to type 'VirtualAction<T>'.
+          Property 'index' is missing in type 'AsyncAction<T>'.
+
+
+
+Standard error:
diff --git a/tests/baselines/reference/wideningTuples3.errors.txt b/tests/baselines/reference/wideningTuples3.errors.txt
index 43c7e349a0c..15e02cfb559 100644
--- a/tests/baselines/reference/wideningTuples3.errors.txt
+++ b/tests/baselines/reference/wideningTuples3.errors.txt
@@ -1,9 +1,16 @@
 tests/cases/conformance/types/tuple/wideningTuples3.ts(3,5): error TS7005: Variable 'b' implicitly has an '[any, any]' type.
+tests/cases/conformance/types/tuple/wideningTuples3.ts(3,9): error TS2322: Type '[undefined, null]' is not assignable to type '[any]'.
+  Types of property 'length' are incompatible.
+    Type '2' is not assignable to type '1'.
 
 
-==== tests/cases/conformance/types/tuple/wideningTuples3.ts (1 errors) ====
+==== tests/cases/conformance/types/tuple/wideningTuples3.ts (2 errors) ====
     var a: [any];
     
     var b = a = [undefined, null];
         ~
-!!! error TS7005: Variable 'b' implicitly has an '[any, any]' type.
\ No newline at end of file
+!!! error TS7005: Variable 'b' implicitly has an '[any, any]' type.
+            ~
+!!! error TS2322: Type '[undefined, null]' is not assignable to type '[any]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '2' is not assignable to type '1'.
\ No newline at end of file
diff --git a/tests/baselines/reference/wideningTuples4.errors.txt b/tests/baselines/reference/wideningTuples4.errors.txt
new file mode 100644
index 00000000000..e38035e7041
--- /dev/null
+++ b/tests/baselines/reference/wideningTuples4.errors.txt
@@ -0,0 +1,14 @@
+tests/cases/conformance/types/tuple/wideningTuples4.ts(3,9): error TS2322: Type '[undefined, null]' is not assignable to type '[any]'.
+  Types of property 'length' are incompatible.
+    Type '2' is not assignable to type '1'.
+
+
+==== tests/cases/conformance/types/tuple/wideningTuples4.ts (1 errors) ====
+    var a: [any];
+    
+    var b = a = [undefined, null];
+            ~
+!!! error TS2322: Type '[undefined, null]' is not assignable to type '[any]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type '2' is not assignable to type '1'.
+    b = ["", ""];
\ No newline at end of file
diff --git a/tests/cases/compiler/APISample_jsdoc.ts b/tests/cases/compiler/APISample_jsdoc.ts
index 2f4e08931d6..d40673f1d9e 100644
--- a/tests/cases/compiler/APISample_jsdoc.ts
+++ b/tests/cases/compiler/APISample_jsdoc.ts
@@ -25,7 +25,7 @@ function parseCommentsIntoDefinition(this: any,
     }
 
     // the comments for a symbol
-    let comments = symbol.getDocumentationComment();
+    let comments = symbol.getDocumentationComment(undefined);
 
     if (comments.length) {
         definition.description = comments.map(comment => comment.kind === "lineBreak" ? comment.text : comment.text.trim().replace(/\r\n/g, "\n")).join("");
diff --git a/tests/cases/compiler/abstractPropertyInConstructor.ts b/tests/cases/compiler/abstractPropertyInConstructor.ts
index 457fdb473b1..b8386f56e1e 100644
--- a/tests/cases/compiler/abstractPropertyInConstructor.ts
+++ b/tests/cases/compiler/abstractPropertyInConstructor.ts
@@ -1,5 +1,5 @@
 abstract class AbstractClass {
-    constructor(str: string) {
+    constructor(str: string, other: AbstractClass) {
         this.method(parseInt(str));
         let val = this.prop.toLowerCase();
 
@@ -8,9 +8,13 @@ abstract class AbstractClass {
         }
         this.cb(str);
 
+        // OK, reference is inside function
         const innerFunction = () => {
             return this.prop;
         }
+
+        // OK, references are to another instance
+        other.cb(other.prop);
     }
 
     abstract prop: string;
@@ -22,3 +26,12 @@ abstract class AbstractClass {
         this.prop = this.prop + "!";
     }
 }
+
+class User {
+    constructor(a: AbstractClass) {
+        a.prop;
+        a.cb("hi");
+        a.method(12);
+        a.method2();
+    }
+}
diff --git a/tests/cases/compiler/commonJsUnusedLocals.ts b/tests/cases/compiler/commonJsUnusedLocals.ts
new file mode 100644
index 00000000000..d1b51aa245b
--- /dev/null
+++ b/tests/cases/compiler/commonJsUnusedLocals.ts
@@ -0,0 +1,8 @@
+// @noUnusedLocals: true
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+
+// @Filename: /a.js
+const x = 0;
+exports.y = 1;
diff --git a/tests/cases/compiler/contextualTypingOfOptionalMembers.tsx b/tests/cases/compiler/contextualTypingOfOptionalMembers.tsx
new file mode 100644
index 00000000000..5e5a9c70c9b
--- /dev/null
+++ b/tests/cases/compiler/contextualTypingOfOptionalMembers.tsx
@@ -0,0 +1,77 @@
+// @noImplicitAny: true
+// @strictNullChecks: true
+// @jsx: preserve
+// @filename: index.tsx
+interface ActionsObject<State> {
+    [prop: string]: (state: State) => State;
+}
+
+interface Options<State, Actions> {
+    state?: State;
+    view?: (state: State, actions: Actions) => any;
+    actions: string | Actions;
+}
+
+declare function app<State, Actions extends ActionsObject<State>>(obj: Options<State, Actions>): void;
+
+app({
+    state: 100,
+    actions: {
+        foo: s => s // Should be typed number => number
+    },
+    view: (s, a) => undefined as any,
+});
+
+
+interface Bar {
+    bar: (a: number) => void;
+}
+
+declare function foo<T extends Bar>(x: string | T): T;
+
+const y = foo({
+    bar(x) { // Should be typed number => void
+    }
+});
+
+interface Options2<State, Actions> {
+    state?: State;
+    view?: (state: State, actions: Actions) => any;
+    actions?: Actions;
+}
+
+declare function app2<State, Actions extends ActionsObject<State>>(obj: Options2<State, Actions>): void;
+
+app2({
+    state: 100,
+    actions: {
+        foo: s => s // Should be typed number => number
+    },
+    view: (s, a) => undefined as any,
+});
+
+
+type ActionsArray<State> = ((state: State) => State)[];
+
+declare function app3<State, Actions extends ActionsArray<State>>(obj: Options<State, Actions>): void;
+
+app3({
+    state: 100,
+    actions: [
+        s => s // Should be typed number => number
+    ],
+    view: (s, a) => undefined as any,
+});
+
+namespace JSX {
+    export interface Element {}
+    export interface IntrinsicElements {}
+}
+
+interface ActionsObjectOr<State> {
+    [prop: string]: ((state: State) => State) | State;
+}
+
+declare function App4<State, Actions extends ActionsObjectOr<State>>(props: Options<State, Actions>["actions"] & { state: State }): JSX.Element;
+
+const a = <App4 state={100} foo={s => s} />; // TODO: should be number => number, but JSX resolution is missing an inferential pass
diff --git a/tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts b/tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts
new file mode 100644
index 00000000000..5fbcd2dbbc5
--- /dev/null
+++ b/tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts
@@ -0,0 +1,25 @@
+// @noImplicitAny: true
+type ADT = {
+    kind: "a",
+    method(x: string): number;
+} | {
+    kind: "b",
+    method(x: number): string;
+};
+
+
+function invoke(item: ADT) {
+    if (item.kind === "a") {
+        item.method("");
+    }
+    else {
+        item.method(42);
+    }
+}
+
+invoke({
+    kind: "a",
+    method(a) {
+        return +a;
+    }
+});
diff --git a/tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts b/tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts
index 8dced33083b..6625973717f 100644
--- a/tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts
+++ b/tests/cases/compiler/declFileTypeAnnotationVisibilityErrorAccessors.ts
@@ -13,7 +13,7 @@ module m {
         export class public2 {
         }
     }
-    
+
     export class c {
         // getter with annotation
         get foo1(): private1 {
@@ -42,7 +42,7 @@ module m {
         }
         set foo5(param: private1) {
         }
-    
+
         // getter with annotation
         get foo11(): public1 {
             return;
diff --git a/tests/cases/compiler/declarationEmitOfTypeofAliasedExport.ts b/tests/cases/compiler/declarationEmitOfTypeofAliasedExport.ts
new file mode 100644
index 00000000000..ab2912a0f1c
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitOfTypeofAliasedExport.ts
@@ -0,0 +1,8 @@
+// @declaration: true
+// @filename: /a.ts
+class C {}
+export { C as D }
+
+// @filename: /b.ts
+import * as a from "./a";
+export default a.D;
diff --git a/tests/cases/compiler/declarationEmitRelativeModuleError.ts b/tests/cases/compiler/declarationEmitRelativeModuleError.ts
new file mode 100644
index 00000000000..f358e81da43
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitRelativeModuleError.ts
@@ -0,0 +1,7 @@
+declare module "b:block" { // <-- no error anymore
+    
+}
+
+declare module "b:/block" { // <-- still an error
+    
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/declarationEmitTypeofDefaultExport.ts b/tests/cases/compiler/declarationEmitTypeofDefaultExport.ts
new file mode 100644
index 00000000000..f081006d864
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitTypeofDefaultExport.ts
@@ -0,0 +1,7 @@
+// @declaration: true
+// @filename: /a.ts
+export default class C {};
+
+// @filename: /b.ts
+import * as a from "./a";
+export default a.default;
diff --git a/tests/cases/compiler/decoratorReferenceOnOtherProperty.ts b/tests/cases/compiler/decoratorReferenceOnOtherProperty.ts
new file mode 100644
index 00000000000..c7465471ed8
--- /dev/null
+++ b/tests/cases/compiler/decoratorReferenceOnOtherProperty.ts
@@ -0,0 +1,25 @@
+// https://github.com/Microsoft/TypeScript/issues/19799
+// @experimentalDecorators: true
+// @emitDecoratorMetadata: true
+// @filename: yoha.ts
+export class Yoha {}
+
+// @filename: index.ts
+import {Yoha} from './yoha';
+
+function foo(...args: any[]) {}
+
+class Bar {
+  yoha(@foo yoha, bar: Yoha) {}
+  //                   ^^^^
+}
+
+// @filename: index2.ts
+import {Yoha} from './yoha';
+
+function foo(...args: any[]) {}
+
+class Bar {
+  yoha(@foo yoha, ...bar: Yoha[]) {}
+  //                      ^^^^
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/decoratorsOnComputedProperties.ts b/tests/cases/compiler/decoratorsOnComputedProperties.ts
new file mode 100644
index 00000000000..cb9cfe5f997
--- /dev/null
+++ b/tests/cases/compiler/decoratorsOnComputedProperties.ts
@@ -0,0 +1,191 @@
+// @target: es6
+// @experimentalDecorators: true
+function x(o: object, k: PropertyKey) { }
+let i = 0;
+function foo(): string { return ++i + ""; }
+
+const fieldNameA: string = "fieldName1";
+const fieldNameB: string = "fieldName2";
+const fieldNameC: string = "fieldName3";
+
+class A {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+}
+
+void class B {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+};
+
+class C {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+    ["some" + "method"]() {}
+}
+
+void class D {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+    ["some" + "method"]() {}
+};
+
+class E {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+}
+
+void class F {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    @x [fieldNameC]: any = null;
+};
+
+class G {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+}
+
+void class H {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+};
+
+class I {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    @x ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+}
+
+void class J {
+    @x ["property"]: any;
+    @x [Symbol.toStringTag]: any;
+    @x ["property2"]: any = 2;
+    @x [Symbol.iterator]: any = null;
+    ["property3"]: any;
+    [Symbol.isConcatSpreadable]: any;
+    ["property4"]: any = 2;
+    [Symbol.match]: any = null;
+    [foo()]: any;
+    @x [foo()]: any;
+    @x [foo()]: any = null;
+    @x ["some" + "method"]() {}
+    [fieldNameA]: any;
+    @x [fieldNameB]: any;
+    ["some" + "method2"]() {}
+    @x [fieldNameC]: any = null;
+};
\ No newline at end of file
diff --git a/tests/cases/compiler/excessPropertyCheckWithUnions.ts b/tests/cases/compiler/excessPropertyCheckWithUnions.ts
index d5a2327380e..240af391cf5 100644
--- a/tests/cases/compiler/excessPropertyCheckWithUnions.ts
+++ b/tests/cases/compiler/excessPropertyCheckWithUnions.ts
@@ -46,7 +46,7 @@ type Overlapping =
     | { b: 3, third: string }
 let over: Overlapping
 
-// these two are not reported because there are two discriminant properties
+// these two are still errors despite their doubled up discriminants
 over = { a: 1, b: 1, first: "ok", second: "error" }
 over = { a: 1, b: 1, first: "ok", third: "error" }
 
diff --git a/tests/cases/compiler/exportDefaultAlias_excludesEverything.ts b/tests/cases/compiler/exportDefaultAlias_excludesEverything.ts
new file mode 100644
index 00000000000..eea8cb1e698
--- /dev/null
+++ b/tests/cases/compiler/exportDefaultAlias_excludesEverything.ts
@@ -0,0 +1,3 @@
+export default interface A {}
+interface B {}
+export default B;
diff --git a/tests/cases/compiler/exportDefaultParenthesize.ts b/tests/cases/compiler/exportDefaultParenthesize.ts
new file mode 100644
index 00000000000..8303eea0234
--- /dev/null
+++ b/tests/cases/compiler/exportDefaultParenthesize.ts
@@ -0,0 +1,36 @@
+// @target: es5
+// @module: esnext
+// @filename: commalist.ts
+export default {
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+    ['foo'+'']: 42,
+};
+
+// @filename: comma.ts
+export default {
+    ['foo']: 42
+};
+
+// @filename: functionexpression.ts
+export default () => 42;
diff --git a/tests/cases/compiler/exportDefaultParenthesizeES6.ts b/tests/cases/compiler/exportDefaultParenthesizeES6.ts
new file mode 100644
index 00000000000..20d1a10cc4c
--- /dev/null
+++ b/tests/cases/compiler/exportDefaultParenthesizeES6.ts
@@ -0,0 +1,4 @@
+// @target: es6
+// @module: esnext
+// @filename: classexpr.ts
+export default (class Foo {} as any);
\ No newline at end of file
diff --git a/tests/cases/compiler/freshLiteralTypesInIntersections.ts b/tests/cases/compiler/freshLiteralTypesInIntersections.ts
new file mode 100644
index 00000000000..b1e73974426
--- /dev/null
+++ b/tests/cases/compiler/freshLiteralTypesInIntersections.ts
@@ -0,0 +1,7 @@
+// @strict: true
+
+// Repro from #19657
+
+declare function func<A extends string, B extends A>(a: A, b: B[]): (ab: A & B) => void;
+const q = func("x" as "x" | "y", ["x"]);
+q("x");
diff --git a/tests/cases/compiler/invariantGenericErrorElaboration.ts b/tests/cases/compiler/invariantGenericErrorElaboration.ts
new file mode 100644
index 00000000000..6191949dd8c
--- /dev/null
+++ b/tests/cases/compiler/invariantGenericErrorElaboration.ts
@@ -0,0 +1,24 @@
+// @strict: true
+
+// Repro from #19746
+
+const wat: Runtype<any> = Num;
+const Foo = Obj({ foo: Num })
+
+interface Runtype<A> {
+  constraint: Constraint<this>
+  witness: A
+}
+
+interface Num extends Runtype<number> {
+  tag: 'number'
+}
+declare const Num: Num
+
+interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+
+interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+  underlying: A,
+  check: (x: A['witness']) => void,
+}
diff --git a/tests/cases/compiler/jsxFactoryAndFragment.tsx b/tests/cases/compiler/jsxFactoryAndFragment.tsx
new file mode 100644
index 00000000000..1d41be5a5e2
--- /dev/null
+++ b/tests/cases/compiler/jsxFactoryAndFragment.tsx
@@ -0,0 +1,7 @@
+//@jsx: react
+//@jsxfactory: h
+
+declare var h: any;
+
+<></>;
+<><span>1</span><><span>2.1</span><span>2.2</span></></>;
\ No newline at end of file
diff --git a/tests/cases/compiler/newAbstractInstance2.ts b/tests/cases/compiler/newAbstractInstance2.ts
new file mode 100644
index 00000000000..a035ccabdcf
--- /dev/null
+++ b/tests/cases/compiler/newAbstractInstance2.ts
@@ -0,0 +1,6 @@
+// @Filename: /a.ts
+export default abstract class {}
+
+// @Filename: /b.ts
+import A from "./a";
+new A();
diff --git a/tests/cases/compiler/reexportWrittenCorrectlyInDeclaration.ts b/tests/cases/compiler/reexportWrittenCorrectlyInDeclaration.ts
new file mode 100644
index 00000000000..71947ca80c1
--- /dev/null
+++ b/tests/cases/compiler/reexportWrittenCorrectlyInDeclaration.ts
@@ -0,0 +1,18 @@
+// https://github.com/Microsoft/TypeScript/issues/8612
+// @declaration: true
+// @filename: ThingA.ts
+export class ThingA { } 
+
+// @filename: ThingB.ts
+export class ThingB { }
+
+// @filename: Things.ts
+export {ThingA} from "./ThingA";
+export {ThingB} from "./ThingB";
+
+// @filename: Test.ts
+import * as things from "./Things";
+
+export class Test {
+    public method = (input: things.ThingA)  => { };
+}
\ No newline at end of file
diff --git a/tests/cases/compiler/tupleTypes.ts b/tests/cases/compiler/tupleTypes.ts
index 80181f8b332..53e5b584b7a 100644
--- a/tests/cases/compiler/tupleTypes.ts
+++ b/tests/cases/compiler/tupleTypes.ts
@@ -15,7 +15,7 @@ t = [];               // Error
 t = [1];              // Error
 t = [1, "hello"];     // Ok
 t = ["hello", 1];     // Error
-t = [1, "hello", 2];  // Ok
+t = [1, "hello", 2];  // Error
 
 var tf: [string, (x: string) => number] = ["hello", x => x.length];
 
diff --git a/tests/cases/conformance/controlFlow/controlFlowStringIndex.ts b/tests/cases/conformance/controlFlow/controlFlowStringIndex.ts
new file mode 100644
index 00000000000..28b75eaba70
--- /dev/null
+++ b/tests/cases/conformance/controlFlow/controlFlowStringIndex.ts
@@ -0,0 +1,11 @@
+// @strict: true
+type A = {
+    other: number | null;
+    [index: string]: number | null
+};
+declare const value: A;
+if (value.foo !== null) {
+    value.foo.toExponential()
+    value.other // should still be number | null
+    value.bar // should still be number | null
+}
diff --git a/tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts b/tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts
new file mode 100644
index 00000000000..1166e1c6ed3
--- /dev/null
+++ b/tests/cases/conformance/expressions/objectLiterals/objectLiteralNormalization.ts
@@ -0,0 +1,52 @@
+// @strict: true
+// @declaration: true
+
+// Object literals in unions are normalized upon widening
+let a1 = [{ a: 0 }, { a: 1, b: "x" }, { a: 2, b: "y", c: true }][0];
+a1.a;  // number
+a1.b;  // string | undefined
+a1.c;  // boolean | undefined
+a1 = { a: 1 };
+a1 = { a: 0, b: 0 };  // Error
+a1 = { b: "y" };  // Error
+a1 = { c: true };  // Error
+
+let a2 = [{ a: 1, b: 2 }, { a: "abc" }, {}][0];
+a2.a;  // string | number | undefined
+a2.b;  // number | undefined
+a2 = { a: 10, b: 20 };
+a2 = { a: "def" };
+a2 = {};
+a2 = { a: "def", b: 20 };  // Error
+a2 = { a: 1 };  // Error
+
+// Object literals containing spreads are not normalized
+declare let b1: { a: string, b: string } | { b: string, c: string };
+let b2 = { ...b1, z: 55 };
+let b3 = { ...b2 };
+
+// Before widening {} acts like { [x: string]: undefined }, which is a
+// subtype of types with all optional properties
+declare let opts: { foo?: string, bar?: string, baz?: boolean };
+let c1 = !true ? {} : opts;
+let c2 = !true ? opts : {};
+let c3 = !true ? { a: 0, b: 0 } : {};
+let c4 = !true ? {} : { a: 0, b: 0 };
+
+// Normalization applies to nested properties
+let d1 = [{ kind: 'a', pos: { x: 0, y: 0 } }, { kind: 'b', pos: !true ? { a: "x" } : { b: 0 } }][0];
+d1.kind;
+d1.pos;
+d1.pos.x;
+d1.pos.y;
+d1.pos.a;
+d1.pos.b;
+
+declare function f<T>(...items: T[]): T;
+declare let data: { a: 1, b: "abc", c: true };
+
+// Object literals are inferred as a single normalized union type
+let e1 = f({ a: 1, b: 2 }, { a: "abc" }, {});
+let e2 = f({}, { a: "abc" }, { a: 1, b: 2 });
+let e3 = f(data, { a: 2 });
+let e4 = f({ a: 2 }, data);
diff --git a/tests/cases/conformance/jsx/checkJsxChildrenProperty14.tsx b/tests/cases/conformance/jsx/checkJsxChildrenProperty14.tsx
new file mode 100644
index 00000000000..cac6fc8dc64
--- /dev/null
+++ b/tests/cases/conformance/jsx/checkJsxChildrenProperty14.tsx
@@ -0,0 +1,48 @@
+// @filename: file.tsx
+// @jsx: preserve
+// @noLib: true
+// @skipLibCheck: true
+// @libFiles: react.d.ts,lib.d.ts
+
+import React = require('react');
+
+interface Prop {
+    a: number,
+    b: string,
+    children: JSX.Element | JSX.Element[];
+}
+
+class Button extends React.Component<any, any> {
+    render() {
+        return (<div>My Button</div>)
+    }
+}
+
+function AnotherButton(p: any) {
+    return <h1>Just Another Button</h1>;
+}
+
+function Comp(p: Prop) {
+    return <div>{p.b}</div>;
+}
+
+// OK
+let k1 = <Comp a={10} b="hi"><></><Button /><AnotherButton /></Comp>;
+let k2 = <Comp a={10} b="hi"><><Button /></><AnotherButton /></Comp>;
+let k3 = <Comp a={10} b="hi"><><Button /><AnotherButton /></></Comp>;
+
+interface SingleChildProp {
+    a: number,
+    b: string,
+    children: JSX.Element;
+}
+
+function SingleChildComp(p: SingleChildProp) {
+    return <div>{p.b}</div>;
+}
+
+// OK
+let k4 = <SingleChildComp a={10} b="hi"><><Button /><AnotherButton /></></SingleChildComp>;
+
+// Error
+let k5 = <SingleChildComp a={10} b="hi"><></><Button /><AnotherButton /></SingleChildComp>;
\ No newline at end of file
diff --git a/tests/cases/conformance/jsx/tsxFragmentErrors.tsx b/tests/cases/conformance/jsx/tsxFragmentErrors.tsx
new file mode 100644
index 00000000000..7806a576fed
--- /dev/null
+++ b/tests/cases/conformance/jsx/tsxFragmentErrors.tsx
@@ -0,0 +1,14 @@
+//@filename: file.tsx
+//@jsx: react
+
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<>hi</div> // Error
+
+<>eof   // Error
\ No newline at end of file
diff --git a/tests/cases/conformance/jsx/tsxFragmentPreserveEmit.tsx b/tests/cases/conformance/jsx/tsxFragmentPreserveEmit.tsx
new file mode 100644
index 00000000000..5f4da955c36
--- /dev/null
+++ b/tests/cases/conformance/jsx/tsxFragmentPreserveEmit.tsx
@@ -0,0 +1,17 @@
+//@filename: file.tsx
+//@jsx: preserve
+
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
\ No newline at end of file
diff --git a/tests/cases/conformance/jsx/tsxFragmentReactEmit.tsx b/tests/cases/conformance/jsx/tsxFragmentReactEmit.tsx
new file mode 100644
index 00000000000..15f4d290cbd
--- /dev/null
+++ b/tests/cases/conformance/jsx/tsxFragmentReactEmit.tsx
@@ -0,0 +1,17 @@
+//@filename: file.tsx
+//@jsx: react
+
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+<></>; // no whitespace
+<    ></   >; // lots of whitespace
+< /*starting wrap*/ ></ /*ending wrap*/>; // comments in the tags
+<>hi</>; // text inside
+<><span>hi</span><div>bye</div></>; // children
+<><span>1</span><><span>2.1</span><span>2.2</span></><span>3</span></>; // nested fragments
\ No newline at end of file
diff --git a/tests/cases/conformance/types/intersection/intersectionTypeInference3.ts b/tests/cases/conformance/types/intersection/intersectionTypeInference3.ts
new file mode 100644
index 00000000000..ceaff10f7f1
--- /dev/null
+++ b/tests/cases/conformance/types/intersection/intersectionTypeInference3.ts
@@ -0,0 +1,20 @@
+// @strict: true
+// @target: es2015
+
+// Repro from #19682
+
+type Nominal<Kind extends string, Type> = Type & {
+    [Symbol.species]: Kind;
+};
+
+type A = Nominal<'A', string>;
+
+declare const a: Set<A>;
+declare const b: Set<A>;
+
+const c1 = Array.from(a).concat(Array.from(b));
+
+// Simpler repro
+
+declare function from<T>(): T[];
+const c2: ReadonlyArray<A> = from();
diff --git a/tests/cases/conformance/types/mapped/mappedTypeRelationships.ts b/tests/cases/conformance/types/mapped/mappedTypeRelationships.ts
index 7acacd6c1d7..9e8639bbb9e 100644
--- a/tests/cases/conformance/types/mapped/mappedTypeRelationships.ts
+++ b/tests/cases/conformance/types/mapped/mappedTypeRelationships.ts
@@ -170,3 +170,15 @@ function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P i
     x = y;
     y = x;  // Error
 }
+
+function f80<T>(t: T): Partial<T> {
+    return t;
+}
+
+function f81<T, K extends keyof T>(t: T, k: K): Partial<T[K]> {
+    return t[k];
+}
+
+function f82<T, K1 extends keyof T, K2 extends keyof T[K1]>(t: T, k1: K1, k2: K2): Partial<T[K1][K2]> {
+    return t[k1][k2];
+}
diff --git a/tests/cases/conformance/types/mapped/mappedTypes5.ts b/tests/cases/conformance/types/mapped/mappedTypes5.ts
new file mode 100644
index 00000000000..38a010da0f5
--- /dev/null
+++ b/tests/cases/conformance/types/mapped/mappedTypes5.ts
@@ -0,0 +1,62 @@
+// @strict: true
+
+function f<T>(p: Partial<T>, r: Readonly<T>, pr: Partial<Readonly<T>>, rp: Readonly<Partial<T>>) {
+    let a1: Partial<T> = p;
+    let a2: Partial<T> = r;
+    let a3: Partial<T> = pr;
+    let a4: Partial<T> = rp;
+    let b1: Readonly<T> = p;  // Error
+    let b2: Readonly<T> = r;
+    let b3: Readonly<T> = pr;  // Error
+    let b4: Readonly<T> = rp;  // Error
+    let c1: Partial<Readonly<T>> = p;
+    let c2: Partial<Readonly<T>> = r;
+    let c3: Partial<Readonly<T>> = pr;
+    let c4: Partial<Readonly<T>> = rp;
+    let d1: Readonly<Partial<T>> = p;
+    let d2: Readonly<Partial<T>> = r;
+    let d3: Readonly<Partial<T>> = pr;
+    let d4: Readonly<Partial<T>> = rp;
+}
+
+// Repro from #17682
+
+type State = {
+    [key: string]: string | boolean | number | null;
+};
+
+type Args1<T extends State> = {
+    readonly previous: Readonly<Partial<T>>;
+    readonly current: Readonly<Partial<T>>;
+};
+
+type Args2<T extends State> = {
+    readonly previous: Partial<Readonly<T>>;
+    readonly current: Partial<Readonly<T>>;
+};
+
+function doit<T extends State>() {
+    let previous: Partial<T> = Object.create(null);
+    let current: Partial<T> = Object.create(null);
+    let args1: Args1<T> = { previous, current };
+    let args2: Args2<T> = { previous, current };
+}
+
+type State2 = { foo: number, bar: string };
+
+type Args3 = {
+    readonly previous: Readonly<Partial<State2>>;
+    readonly current: Readonly<Partial<State2>>;
+};
+
+type Args4 = {
+    readonly previous: Partial<Readonly<State2>>;
+    readonly current: Partial<Readonly<State2>>;
+};
+
+function doit2() {
+    let previous: Partial<State2> = Object.create(null);
+    let current: Partial<State2> = Object.create(null);
+    let args1: Args3 = { previous, current };
+    let args2: Args4 = { previous, current };
+}
diff --git a/tests/cases/conformance/types/never/neverInference.ts b/tests/cases/conformance/types/never/neverInference.ts
new file mode 100644
index 00000000000..1258a35e3d3
--- /dev/null
+++ b/tests/cases/conformance/types/never/neverInference.ts
@@ -0,0 +1,24 @@
+// @strict: true
+
+declare function f<T>(x: T[]): T;
+
+let neverArray: never[] = [];
+
+let a1 = f([]);  // {}
+let a2 = f(neverArray);  // never
+
+// Repro from #19576
+
+type Comparator<T> = (x: T, y: T) => number;
+
+interface LinkedList<T> {
+    comparator: Comparator<T>,
+    nodes: Node<T>
+}
+
+type Node<T> = { value: T, next: Node<T> } | null
+
+declare function compareNumbers(x: number, y: number): number;
+declare function mkList<T>(items: T[], comparator: Comparator<T>): LinkedList<T>;
+
+const list: LinkedList<number> = mkList([], compareNumbers);
diff --git a/tests/cases/conformance/types/never/neverTypeErrors1.ts b/tests/cases/conformance/types/never/neverTypeErrors1.ts
index 8d78e863098..deab74c6690 100644
--- a/tests/cases/conformance/types/never/neverTypeErrors1.ts
+++ b/tests/cases/conformance/types/never/neverTypeErrors1.ts
@@ -6,6 +6,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 
 function f2(): never {
diff --git a/tests/cases/conformance/types/never/neverTypeErrors2.ts b/tests/cases/conformance/types/never/neverTypeErrors2.ts
index 635d1c9c6ad..2c637580d00 100644
--- a/tests/cases/conformance/types/never/neverTypeErrors2.ts
+++ b/tests/cases/conformance/types/never/neverTypeErrors2.ts
@@ -8,6 +8,7 @@ function f1() {
     x = undefined;
     x = null;
     x = {};
+    x();
 }
 
 function f2(): never {
diff --git a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
index 83649d465f1..13ddc4f71d3 100644
--- a/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
+++ b/tests/cases/conformance/types/spread/objectSpreadIndexSignature.ts
@@ -11,3 +11,7 @@ ii[1001];
 
 declare const b: boolean;
 indexed3 = { ...b ? indexed3 : undefined };
+
+declare var roindex: { readonly [x:string]: number };
+var writable = { ...roindex };
+writable.a = 0;  // should be ok.
diff --git a/tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts b/tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts
index 0f486d843ea..85a035d472b 100644
--- a/tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts
+++ b/tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts
@@ -1,6 +1,7 @@
 interface StrNum extends Array<string|number> {
     0: string;
     1: number;
+    length: 2;
 }
 
 var x: [string, number];
@@ -8,6 +9,7 @@ var y: StrNum
 var z: {
     0: string;
     1: number;
+    length: 2;
 }
 
 var [a, b, c] = x;
diff --git a/tests/cases/conformance/types/tuple/castingTuple.ts b/tests/cases/conformance/types/tuple/castingTuple.ts
index cf5c58af346..2ffc22ff34c 100644
--- a/tests/cases/conformance/types/tuple/castingTuple.ts
+++ b/tests/cases/conformance/types/tuple/castingTuple.ts
@@ -11,6 +11,8 @@ enum E2 { one }
 var numStrTuple: [number, string] = [5, "foo"];
 var emptyObjTuple = <[{}, {}]>numStrTuple;
 var numStrBoolTuple = <[number, string, boolean]>numStrTuple;
+var shorter = numStrBoolTuple as [number, string]
+var longer = numStrTuple as [number, string, boolean]
 var classCDTuple: [C, D] = [new C(), new D()];
 var interfaceIITuple = <[I, I]>classCDTuple;
 var classCDATuple = <[C, D, A]>classCDTuple;
diff --git a/tests/cases/conformance/types/tuple/strictTupleLength.ts b/tests/cases/conformance/types/tuple/strictTupleLength.ts
new file mode 100644
index 00000000000..eaa9111e557
--- /dev/null
+++ b/tests/cases/conformance/types/tuple/strictTupleLength.ts
@@ -0,0 +1,19 @@
+var t0: [];
+var t1: [number];
+var t2: [number, number];
+var arr: number[];
+
+var len0: 0 = t0.length;
+var len1: 1 = t1.length;
+var len2: 2 = t2.length;
+var lena: number = arr.length;
+
+var t1 = t2; // error
+var t2 = t1; // error
+
+type A<T extends any[]> = T['length'];
+var b: A<[boolean]>;
+var c: 1 = b;
+
+t1 = arr; // error with or without strict
+arr = t1; // ok with or without strict
diff --git a/tests/cases/conformance/types/typeAliases/genericTypeAliases.ts b/tests/cases/conformance/types/typeAliases/genericTypeAliases.ts
index e26279a8a41..8c8ab3291fa 100644
--- a/tests/cases/conformance/types/typeAliases/genericTypeAliases.ts
+++ b/tests/cases/conformance/types/typeAliases/genericTypeAliases.ts
@@ -39,12 +39,12 @@ type Strange<T> = string;  // Type parameter not used
 var s: Strange<number>;
 s = "hello";
 
-interface Tuple<A, B> {
+interface AB<A, B> {
     a: A;
     b: B;
 }
 
-type Pair<T> = Tuple<T, T>;
+type Pair<T> = AB<T, T>;
 
 interface TaggedPair<T> extends Pair<T> {
     tag: string;
diff --git a/tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts b/tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts
index ed8d724300d..ea16201ae91 100644
--- a/tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts
+++ b/tests/cases/conformance/types/typeRelationships/recursiveTypes/nominalSubtypeCheckOfTypeParameter.ts
@@ -1,17 +1,17 @@
-interface Tuple<T, S> {
+interface BinaryTuple<T, S> {
     first: T
-      second: S
+    second: S
 }
 
 interface Sequence<T> {
     hasNext(): boolean
-      pop(): T
-      zip<S>(seq: Sequence<S>): Sequence<Tuple<T, S>>
+    pop(): T
+    zip<S>(seq: Sequence<S>): Sequence<BinaryTuple<T, S>>
 }
 
 // error, despite the fact that the code explicitly says List<T> extends Sequence<T>, the current rules for infinitely expanding type references 
 // perform nominal subtyping checks that allow variance for type arguments, but not nominal subtyping for the generic type itself
 interface List<T> extends Sequence<T> {
     getLength(): number
-      zip<S>(seq: Sequence<S>): List<Tuple<T, S>>
+    zip<S>(seq: Sequence<S>): List<BinaryTuple<T, S>>
 }
diff --git a/tests/cases/fourslash/ambientShorthandGotoDefinition.ts b/tests/cases/fourslash/ambientShorthandGotoDefinition.ts
index 74e348beb74..f0e717999cf 100644
--- a/tests/cases/fourslash/ambientShorthandGotoDefinition.ts
+++ b/tests/cases/fourslash/ambientShorthandGotoDefinition.ts
@@ -5,10 +5,10 @@
 
 // @Filename: user.ts
 ///////<reference path="declarations.d.ts"/>
-////import /*importFoo*/foo, {bar} from "jquery";
-////import * as /*importBaz*/baz from "jquery";
-////import /*importBang*/bang = require("jquery");
-////foo/*useFoo*/(bar/*useBar*/, baz/*useBaz*/, bang/*useBang*/);
+////import [|/*importFoo*/foo|], {bar} from "jquery";
+////import * as [|/*importBaz*/baz|] from "jquery";
+////import [|/*importBang*/bang|] = require("jquery");
+////[|foo/*useFoo*/|]([|bar/*useBar*/|], [|baz/*useBaz*/|], [|bang/*useBang*/|]);
 
 verify.quickInfoAt("useFoo", "import foo");
 verify.goToDefinition({
diff --git a/tests/cases/fourslash/commentsInheritance.ts b/tests/cases/fourslash/commentsInheritance.ts
index 7afe18f400c..985c55c7947 100644
--- a/tests/cases/fourslash/commentsInheritance.ts
+++ b/tests/cases/fourslash/commentsInheritance.ts
@@ -263,8 +263,8 @@ verify.quickInfos({
 });
 
 goTo.marker('6');
-verify.completionListContains("i1_p1", "(property) c1.i1_p1: number", "");
-verify.completionListContains("i1_f1", "(method) c1.i1_f1(): void", "");
+verify.completionListContains("i1_p1", "(property) c1.i1_p1: number", "i1_p1");
+verify.completionListContains("i1_f1", "(method) c1.i1_f1(): void", "i1_f1");
 verify.completionListContains("i1_l1", "(property) c1.i1_l1: () => void", "");
 verify.completionListContains("i1_nc_p1", "(property) c1.i1_nc_p1: number", "");
 verify.completionListContains("i1_nc_f1", "(method) c1.i1_nc_f1(): void", "");
@@ -276,7 +276,7 @@ verify.completionListContains("nc_p1", "(property) c1.nc_p1: number", "c1_nc_p1"
 verify.completionListContains("nc_f1", "(method) c1.nc_f1(): void", "c1_nc_f1");
 verify.completionListContains("nc_l1", "(property) c1.nc_l1: () => void", "");
 goTo.marker('7');
-verify.currentSignatureHelpDocCommentIs("");
+verify.currentSignatureHelpDocCommentIs("i1_f1");
 goTo.marker('8');
 verify.currentSignatureHelpDocCommentIs("");
 goTo.marker('9');
@@ -294,7 +294,7 @@ verify.currentSignatureHelpDocCommentIs("");
 
 verify.quickInfos({
     "6iq": "var c1_i: c1",
-    "7q": "(method) c1.i1_f1(): void",
+    "7q": ["(method) c1.i1_f1(): void", "i1_f1"],
     "8q": "(method) c1.i1_nc_f1(): void",
     "9q": ["(method) c1.f1(): void", "c1_f1"],
     "10q": ["(method) c1.nc_f1(): void", "c1_nc_f1"],
@@ -515,7 +515,7 @@ verify.quickInfos({
     "39q": ["(method) i2.f1(): void", "i2 f1"],
     "40q": "(method) i2.nc_f1(): void",
     "l37q": "(property) i2.i2_l1: () => void",
-    "l38q": "(property) i2.i2_nc_l1: () => void", 
+    "l38q": "(property) i2.i2_nc_l1: () => void",
     "l39q": "(property) i2.l1: () => void",
     "l40q": "(property) i2.nc_l1: () => void",
 });
diff --git a/tests/cases/fourslash/commentsInterface.ts b/tests/cases/fourslash/commentsInterface.ts
index 7a09329a0fd..e2223326274 100644
--- a/tests/cases/fourslash/commentsInterface.ts
+++ b/tests/cases/fourslash/commentsInterface.ts
@@ -113,7 +113,7 @@ goTo.marker('16');
 verify.currentSignatureHelpDocCommentIs("new method");
 verify.currentParameterHelpArgumentDocCommentIs("param");
 verify.quickInfos({
-    "16q": ["var i2_i: new i2(i: i1) => any", "new method"],
+    "16q": ["var i2_i: i2\nnew (i: i1) => any", "new method"],
 
     17: "var i2_i_nc_x: number",
     18: "(property) i2.nc_x: number",
@@ -133,7 +133,7 @@ verify.quickInfos({
 goTo.marker('24');
 verify.currentSignatureHelpDocCommentIs("this is call signature");
 verify.currentParameterHelpArgumentDocCommentIs("paramhelp a");
-verify.quickInfoAt("24q", "var i2_i: i2(a: number, b: number) => number", "this is call signature");
+verify.quickInfoAt("24q", "var i2_i: i2\n(a: number, b: number) => number", "this is call signature");
 
 goTo.marker('25');
 verify.currentSignatureHelpDocCommentIs("this is call signature");
diff --git a/tests/cases/fourslash/commentsOverloads.ts b/tests/cases/fourslash/commentsOverloads.ts
index 6add2609897..1068e1e6fe1 100644
--- a/tests/cases/fourslash/commentsOverloads.ts
+++ b/tests/cases/fourslash/commentsOverloads.ts
@@ -296,34 +296,34 @@ verify.completionListContains('f4', 'function f4(a: number): number (+1 overload
 
 goTo.marker('18');
 verify.not.completionListContains('i1', 'interface i1', '');
-verify.completionListContains('i1_i', 'var i1_i: new i1(b: number) => any (+1 overload)', '');
+verify.completionListContains('i1_i', 'var i1_i: i1\nnew (b: number) => any (+1 overload)', '');
 verify.not.completionListContains('i2', 'interface i2', '');
-verify.completionListContains('i2_i', 'var i2_i: new i2(a: string) => any (+1 overload)', '');
+verify.completionListContains('i2_i', 'var i2_i: i2\nnew (a: string) => any (+1 overload)', '');
 verify.not.completionListContains('i3', 'interface i3', '');
-verify.completionListContains('i3_i', 'var i3_i: new i3(a: string) => any (+1 overload)', 'new 1');
+verify.completionListContains('i3_i', 'var i3_i: i3\nnew (a: string) => any (+1 overload)', 'new 1');
 verify.not.completionListContains('i4', 'interface i4', '');
-verify.completionListContains('i4_i', 'var i4_i: new i4(a: string) => any (+1 overload)', '');
+verify.completionListContains('i4_i', 'var i4_i: i4\nnew (a: string) => any (+1 overload)', '');
 
 goTo.marker('19');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("19q", "var i1_i: new i1(b: number) => any (+1 overload)");
+verify.quickInfoAt("19q", "var i1_i: i1\nnew (b: number) => any (+1 overload)");
 
 goTo.marker('20');
 verify.currentSignatureHelpDocCommentIs("new 1");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("20q", "var i1_i: new i1(a: string) => any (+1 overload)", "new 1");
+verify.quickInfoAt("20q", "var i1_i: i1\nnew (a: string) => any (+1 overload)", "new 1");
 
 goTo.marker('21');
 verify.currentSignatureHelpDocCommentIs("this signature 1");
 verify.currentParameterHelpArgumentDocCommentIs("param a");
-verify.quickInfoAt("21q", "var i1_i: i1(a: number) => number (+1 overload)", "this signature 1");
+verify.quickInfoAt("21q", "var i1_i: i1\n(a: number) => number (+1 overload)", "this signature 1");
 
 goTo.marker('22');
 verify.currentSignatureHelpDocCommentIs("this is signature 2");
 verify.currentParameterHelpArgumentDocCommentIs("");
 goTo.marker('22q');
-verify.quickInfoAt("22q", "var i1_i: i1(b: string) => number (+1 overload)", "this is signature 2");
+verify.quickInfoAt("22q", "var i1_i: i1\n(b: string) => number (+1 overload)", "this is signature 2");
 
 goTo.marker('23');
 verify.completionListContains('foo', '(method) i1.foo(a: number): number (+1 overload)', 'foo 1');
@@ -374,62 +374,62 @@ verify.quickInfoAt("31q", "(method) i1.foo4(b: string): number (+1 overload)");
 goTo.marker('32');
 verify.currentSignatureHelpDocCommentIs("new 2");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("32q", "var i2_i: new i2(b: number) => any (+1 overload)", "new 2");
+verify.quickInfoAt("32q", "var i2_i: i2\nnew (b: number) => any (+1 overload)", "new 2");
 
 goTo.marker('33');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("33q", "var i2_i: new i2(a: string) => any (+1 overload)");
+verify.quickInfoAt("33q", "var i2_i: i2\nnew (a: string) => any (+1 overload)");
 
 goTo.marker('34');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("34q", "var i2_i: i2(a: number) => number (+1 overload)");
+verify.quickInfoAt("34q", "var i2_i: i2\n(a: number) => number (+1 overload)");
 
 goTo.marker('35');
 verify.currentSignatureHelpDocCommentIs("this is signature 2");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("35q", "var i2_i: i2(b: string) => number (+1 overload)", "this is signature 2");
+verify.quickInfoAt("35q", "var i2_i: i2\n(b: string) => number (+1 overload)", "this is signature 2");
 
 goTo.marker('36');
 verify.currentSignatureHelpDocCommentIs("new 2");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("36q", "var i3_i: new i3(b: number) => any (+1 overload)", "new 2");
+verify.quickInfoAt("36q", "var i3_i: i3\nnew (b: number) => any (+1 overload)", "new 2");
 
 goTo.marker('37');
 verify.currentSignatureHelpDocCommentIs("new 1");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("37q", "var i3_i: new i3(a: string) => any (+1 overload)", "new 1");
+verify.quickInfoAt("37q", "var i3_i: i3\nnew (a: string) => any (+1 overload)", "new 1");
 
 goTo.marker('38');
 verify.currentSignatureHelpDocCommentIs("this is signature 1");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("38q", "var i3_i: i3(a: number) => number (+1 overload)", "this is signature 1");
+verify.quickInfoAt("38q", "var i3_i: i3\n(a: number) => number (+1 overload)", "this is signature 1");
 
 goTo.marker('39');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("39q", "var i3_i: i3(b: string) => number (+1 overload)");
+verify.quickInfoAt("39q", "var i3_i: i3\n(b: string) => number (+1 overload)");
 
 goTo.marker('40');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("40q", "var i4_i: new i4(b: number) => any (+1 overload)");
+verify.quickInfoAt("40q", "var i4_i: i4\nnew (b: number) => any (+1 overload)");
 
 goTo.marker('41');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("41q", "var i4_i: new i4(a: string) => any (+1 overload)");
+verify.quickInfoAt("41q", "var i4_i: i4\nnew (a: string) => any (+1 overload)");
 
 goTo.marker('42');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("42q", "var i4_i: i4(a: number) => number (+1 overload)");
+verify.quickInfoAt("42q", "var i4_i: i4\n(a: number) => number (+1 overload)");
 
 goTo.marker('43');
 verify.currentSignatureHelpDocCommentIs("");
 verify.currentParameterHelpArgumentDocCommentIs("");
-verify.quickInfoAt("43q", "var i4_i: i4(b: string) => number (+1 overload)");
+verify.quickInfoAt("43q", "var i4_i: i4\n(b: string) => number (+1 overload)");
 
 goTo.marker('44');
 verify.completionListContains('prop1', '(method) c.prop1(a: number): number (+1 overload)', '');
diff --git a/tests/cases/fourslash/completionForStringLiteral13.ts b/tests/cases/fourslash/completionForStringLiteral13.ts
new file mode 100644
index 00000000000..391a1ed5083
--- /dev/null
+++ b/tests/cases/fourslash/completionForStringLiteral13.ts
@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts'/>
+
+////interface SymbolConstructor {
+////    readonly species: symbol;
+////}
+////var Symbol: SymbolConstructor;
+////interface PromiseConstructor {
+////  [Symbol.species]: PromiseConstructor;
+////}
+////var Promise: PromiseConstructor;
+////Promise["/*1*/"];
+
+goTo.marker('1');
+verify.not.completionListContains("__@species");
diff --git a/tests/cases/fourslash/completionForStringLiteralExport.ts b/tests/cases/fourslash/completionForStringLiteralExport.ts
new file mode 100644
index 00000000000..649148bb15d
--- /dev/null
+++ b/tests/cases/fourslash/completionForStringLiteralExport.ts
@@ -0,0 +1,37 @@
+/// <reference path='fourslash.ts' />
+
+// Should define spans for replacement that appear after the last directory seperator in export statements
+
+// @typeRoots: my_typings
+
+// @Filename: test.ts
+//// export * from "./some/*0*/
+//// export * from "./sub/some/*1*/";
+//// export * from "some-/*2*/";
+//// export * from "..//*3*/";
+//// export {} from ".//*4*/";
+
+
+// @Filename: someFile1.ts
+//// /*someFile1*/
+
+// @Filename: sub/someFile2.ts
+//// /*someFile2*/
+
+// @Filename: my_typings/some-module/index.d.ts
+//// export var x = 9;
+
+goTo.marker("0");
+verify.completionListContains("someFile1");
+
+goTo.marker("1");
+verify.completionListContains("someFile2");
+
+goTo.marker("2");
+verify.completionListContains("some-module");
+
+goTo.marker("3");
+verify.completionListContains("fourslash");
+
+goTo.marker("4");
+verify.completionListContains("someFile1");
diff --git a/tests/cases/fourslash/completionForStringLiteralWithDynamicImport.ts b/tests/cases/fourslash/completionForStringLiteralWithDynamicImport.ts
new file mode 100644
index 00000000000..8e823991c0b
--- /dev/null
+++ b/tests/cases/fourslash/completionForStringLiteralWithDynamicImport.ts
@@ -0,0 +1,33 @@
+/// <reference path='fourslash.ts' />
+
+// Should define spans for replacement that appear after the last directory seperator in dynamic import statements
+
+// @typeRoots: my_typings
+
+// @Filename: test.ts
+//// const a = import("./some/*0*/
+//// const a = import("./sub/some/*1*/");
+//// const a = import("some-/*2*/");
+//// const a = import("..//*3*/");
+
+
+// @Filename: someFile1.ts
+//// /*someFile1*/
+
+// @Filename: sub/someFile2.ts
+//// /*someFile2*/
+
+// @Filename: my_typings/some-module/index.d.ts
+//// export var x = 9;
+
+goTo.marker("0");
+verify.completionListContains("someFile1");
+
+goTo.marker("1");
+verify.completionListContains("someFile2");
+
+goTo.marker("2");
+verify.completionListContains("some-module");
+
+goTo.marker("3");
+verify.completionListContains("fourslash");
diff --git a/tests/cases/fourslash/completionsForRecursiveGenericTypesMember.ts b/tests/cases/fourslash/completionsForRecursiveGenericTypesMember.ts
new file mode 100644
index 00000000000..993b9eb73ac
--- /dev/null
+++ b/tests/cases/fourslash/completionsForRecursiveGenericTypesMember.ts
@@ -0,0 +1,18 @@
+/// <reference path="fourslash.ts" />
+
+//// export class TestBase<T extends TestBase<T>>
+//// {   
+////     public publicMethod(p: any): void {}
+////     private privateMethod(p: any): void {}
+////     protected protectedMethod(p: any): void {}
+////     public test(t: T): void
+////     {
+////         t./**/
+////     }
+//// }
+
+goTo.marker();
+
+verify.completionListContains('publicMethod');
+verify.completionListContains('privateMethod');
+verify.completionListContains('protectedMethod');
diff --git a/tests/cases/fourslash/completionsImport_default_addToNamedImports.ts b/tests/cases/fourslash/completionsImport_default_addToNamedImports.ts
index 734b3ff0f66..7a7a220ca77 100644
--- a/tests/cases/fourslash/completionsImport_default_addToNamedImports.ts
+++ b/tests/cases/fourslash/completionsImport_default_addToNamedImports.ts
@@ -9,7 +9,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_default_addToNamespaceImport.ts b/tests/cases/fourslash/completionsImport_default_addToNamespaceImport.ts
index d4a81bc5272..43e3854c5e3 100644
--- a/tests/cases/fourslash/completionsImport_default_addToNamespaceImport.ts
+++ b/tests/cases/fourslash/completionsImport_default_addToNamespaceImport.ts
@@ -8,7 +8,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_default_alreadyExistedWithRename.ts b/tests/cases/fourslash/completionsImport_default_alreadyExistedWithRename.ts
index f49f5850043..ed34d5e4e9c 100644
--- a/tests/cases/fourslash/completionsImport_default_alreadyExistedWithRename.ts
+++ b/tests/cases/fourslash/completionsImport_default_alreadyExistedWithRename.ts
@@ -8,7 +8,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_default_didNotExistBefore.ts b/tests/cases/fourslash/completionsImport_default_didNotExistBefore.ts
index fb4d65a1c52..82b8e92a570 100644
--- a/tests/cases/fourslash/completionsImport_default_didNotExistBefore.ts
+++ b/tests/cases/fourslash/completionsImport_default_didNotExistBefore.ts
@@ -7,7 +7,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_matching.ts b/tests/cases/fourslash/completionsImport_matching.ts
index edecf3592cd..f5f9108fa6c 100644
--- a/tests/cases/fourslash/completionsImport_matching.ts
+++ b/tests/cases/fourslash/completionsImport_matching.ts
@@ -14,9 +14,10 @@
 
 goTo.marker("");
 
-verify.not.completionListContains({ name: "abcde", source: "/a" });
-verify.not.completionListContains({ name: "dbf", source: "/a" });
+const options = { includeExternalModuleExports: true };
+verify.not.completionListContains({ name: "abcde", source: "/a" }, undefined, undefined, undefined, undefined, undefined, options);
+verify.not.completionListContains({ name: "dbf", source: "/a" }, undefined, undefined, undefined, undefined, undefined, options);
 
-verify.completionListContains({ name: "bdf", source: "/a" }, "function bdf(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
-verify.completionListContains({ name: "abcdef", source: "/a" }, "function abcdef(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
-verify.completionListContains({ name: "BDF", source: "/a" }, "function BDF(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "bdf", source: "/a" }, "function bdf(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, options);
+verify.completionListContains({ name: "abcdef", source: "/a" }, "function abcdef(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, options);
+verify.completionListContains({ name: "BDF", source: "/a" }, "function BDF(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, options);
diff --git a/tests/cases/fourslash/completionsImport_multipleWithSameName.ts b/tests/cases/fourslash/completionsImport_multipleWithSameName.ts
index 825a4ca0a97..c9bb33d6c79 100644
--- a/tests/cases/fourslash/completionsImport_multipleWithSameName.ts
+++ b/tests/cases/fourslash/completionsImport_multipleWithSameName.ts
@@ -14,9 +14,10 @@
 ////fo/**/
 
 goTo.marker("");
-verify.completionListContains("foo", "var foo: number", "", "var");
-verify.completionListContains({ name: "foo", source: "/a" }, "const foo: 0", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true);
-verify.completionListContains({ name: "foo", source: "/b" }, "const foo: 1", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true);
+const options = { includeExternalModuleExports: true };
+verify.completionListContains("foo", "var foo: number", "", "var", undefined, undefined, options);
+verify.completionListContains({ name: "foo", source: "/a" }, "const foo: 0", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true, options);
+verify.completionListContains({ name: "foo", source: "/b" }, "const foo: 1", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true, options);
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_named_addToNamedImports.ts b/tests/cases/fourslash/completionsImport_named_addToNamedImports.ts
index 5444b25692a..b11552d0327 100644
--- a/tests/cases/fourslash/completionsImport_named_addToNamedImports.ts
+++ b/tests/cases/fourslash/completionsImport_named_addToNamedImports.ts
@@ -9,7 +9,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_named_didNotExistBefore.ts b/tests/cases/fourslash/completionsImport_named_didNotExistBefore.ts
index 809e40e7cf2..9397ee004c2 100644
--- a/tests/cases/fourslash/completionsImport_named_didNotExistBefore.ts
+++ b/tests/cases/fourslash/completionsImport_named_didNotExistBefore.ts
@@ -9,9 +9,10 @@
 ////t/**/
 
 goTo.marker("");
-verify.completionListContains({ name: "Test1", source: "/a" }, "function Test1(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
-verify.completionListContains("Test2", "import Test2", "", "alias", /*spanIndex*/ undefined, /*hasAction*/ undefined);
-verify.not.completionListContains({ name: "Test2", source: "/a" });
+const options = { includeExternalModuleExports: true };
+verify.completionListContains({ name: "Test1", source: "/a" }, "function Test1(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, options);
+verify.completionListContains("Test2", "import Test2", "", "alias", /*spanIndex*/ undefined, /*hasAction*/ undefined, options);
+verify.not.completionListContains({ name: "Test2", source: "/a" }, undefined, undefined, undefined, undefined, undefined, options);
 
 verify.applyCodeActionFromCompletion("", {
     name: "Test1",
diff --git a/tests/cases/fourslash/completionsImport_named_namespaceImportExists.ts b/tests/cases/fourslash/completionsImport_named_namespaceImportExists.ts
index 70cd75a4e41..d4602795280 100644
--- a/tests/cases/fourslash/completionsImport_named_namespaceImportExists.ts
+++ b/tests/cases/fourslash/completionsImport_named_namespaceImportExists.ts
@@ -8,7 +8,7 @@
 ////f/**/;
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_ofAlias.ts b/tests/cases/fourslash/completionsImport_ofAlias.ts
index 27bc29fa210..e7cdb366497 100644
--- a/tests/cases/fourslash/completionsImport_ofAlias.ts
+++ b/tests/cases/fourslash/completionsImport_ofAlias.ts
@@ -15,9 +15,10 @@
 ////fo/**/
 
 goTo.marker("");
-// https://github.com/Microsoft/TypeScript/issues/14003
-verify.completionListContains({ name: "foo", source: "/a" }, "import foo", "", "alias", /*spanIndex*/ undefined, /*hasAction*/ true);
-verify.not.completionListContains({ name: "foo", source: "/a_reexport" });
+const options = { includeExternalModuleExports: true };
+// TODO: https://github.com/Microsoft/TypeScript/issues/14003
+verify.completionListContains({ name: "foo", source: "/a" }, "import foo", "", "alias", /*spanIndex*/ undefined, /*hasAction*/ true, options);
+verify.not.completionListContains({ name: "foo", source: "/a_reexport" }, undefined, undefined, undefined, undefined, undefined, options);
 
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
diff --git a/tests/cases/fourslash/completionsImport_previousTokenIsSemicolon.ts b/tests/cases/fourslash/completionsImport_previousTokenIsSemicolon.ts
index 5eddb5037c1..93c2cc01b0b 100644
--- a/tests/cases/fourslash/completionsImport_previousTokenIsSemicolon.ts
+++ b/tests/cases/fourslash/completionsImport_previousTokenIsSemicolon.ts
@@ -8,4 +8,4 @@
 /////**/
 
 goTo.marker("");
-verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true);
+verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): void", "", "function", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
diff --git a/tests/cases/fourslash/completionsImport_require.ts b/tests/cases/fourslash/completionsImport_require.ts
new file mode 100644
index 00000000000..e0a6b00d462
--- /dev/null
+++ b/tests/cases/fourslash/completionsImport_require.ts
@@ -0,0 +1,42 @@
+/// <reference path="fourslash.ts" />
+
+// @allowJs: true
+
+// @Filename: /a.ts
+////export const foo = 0;
+
+// @Filename: /b.js
+////const a = require("./a");
+////fo/*b*/
+
+// @Filename: /c.js
+////const a = import("./a");
+////fo/*c*/
+
+goTo.marker("b");
+verify.completionListContains({ name: "foo", source: "/a" }, "const foo: 0", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
+
+verify.applyCodeActionFromCompletion("b", {
+    name: "foo",
+    source: "/a",
+    description: `Import 'foo' from "./a".`,
+    // TODO: GH#18445
+    newFileContent: `import { foo } from "./a";\r
+\r
+const a = require("./a");
+fo`,
+});
+
+goTo.marker("c");
+verify.completionListContains({ name: "foo", source: "/a" }, "const foo: 0", "", "const", /*spanIndex*/ undefined, /*hasAction*/ true, { includeExternalModuleExports: true });
+
+verify.applyCodeActionFromCompletion("c", {
+    name: "foo",
+    source: "/a",
+    description: `Import 'foo' from "./a".`,
+    // TODO: GH#18445
+    newFileContent: `import { foo } from "./a";\r
+\r
+const a = import("./a");
+fo`,
+});
diff --git a/tests/cases/fourslash/completionsImport_shadowedByLocal.ts b/tests/cases/fourslash/completionsImport_shadowedByLocal.ts
index d35a021acc7..20e8c4a4bc8 100644
--- a/tests/cases/fourslash/completionsImport_shadowedByLocal.ts
+++ b/tests/cases/fourslash/completionsImport_shadowedByLocal.ts
@@ -8,5 +8,6 @@
 ////fo/**/
 
 goTo.marker("");
-verify.completionListContains("foo", "const foo: 1", "", "const");
-verify.not.completionListContains({ name: "foo", source: "/a" });
+const options = { includeExternalModuleExports: true };
+verify.completionListContains("foo", "const foo: 1", "", "const", undefined, undefined, options);
+verify.not.completionListContains({ name: "foo", source: "/a" }, undefined, undefined, undefined, undefined, undefined, options);
diff --git a/tests/cases/fourslash/completionsJsxAttribute.ts b/tests/cases/fourslash/completionsJsxAttribute.ts
new file mode 100644
index 00000000000..29e6122ef18
--- /dev/null
+++ b/tests/cases/fourslash/completionsJsxAttribute.ts
@@ -0,0 +1,22 @@
+/// <reference path="fourslash.ts" />
+
+// @jsx: preserve
+
+// @Filename: /a.tsx
+////declare namespace JSX {
+////    interface Element {}
+////    interface IntrinsicElements {
+////        div: {
+////            /** Doc */
+////            foo: string
+////        }
+////    }
+////}
+////
+////<div /**/></div>;
+
+goTo.marker();
+verify.completionEntryDetailIs("foo", "(JSX attribute) foo: string", "Doc ", "JSX attribute", []);
+edit.insert("f");
+verify.completionEntryDetailIs("foo", "(JSX attribute) foo: string", "Doc ", "JSX attribute", []);
+
diff --git a/tests/cases/fourslash/completionsPaths.ts b/tests/cases/fourslash/completionsPaths.ts
new file mode 100644
index 00000000000..9473ae54b25
--- /dev/null
+++ b/tests/cases/fourslash/completionsPaths.ts
@@ -0,0 +1,21 @@
+/// <reference path="fourslash.ts" />
+
+// @moduleResolution: node
+
+// @Filename: /node_modules/x/foo.d.ts
+////not read
+
+// @Filename: /node_modules/x/bar.d.ts
+////not read
+
+// @Filename: /src/node_modules/y/index.d.ts
+////not read
+
+// @Filename: /src/a.ts
+////import {} from "/*1*/";
+
+// @Filename: /src/folder/b.ts
+////import {} from "x//*2*/";
+
+verify.completionsAt("1", ["y", "x"]);
+verify.completionsAt("2", ["bar", "foo"]);
diff --git a/tests/cases/fourslash/definition.ts b/tests/cases/fourslash/definition.ts
index 705cdd65583..f91d8a9e346 100644
--- a/tests/cases/fourslash/definition.ts
+++ b/tests/cases/fourslash/definition.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import n = require('./a/*1*/');
+////import n = require([|'./a/*1*/'|]);
 ////var x = new n.Foo();
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/definitionNameOnEnumMember.ts b/tests/cases/fourslash/definitionNameOnEnumMember.ts
index b82b0dc0465..5529dc2bb55 100644
--- a/tests/cases/fourslash/definitionNameOnEnumMember.ts
+++ b/tests/cases/fourslash/definitionNameOnEnumMember.ts
@@ -5,7 +5,7 @@
 ////    secondMember,
 ////    thirdMember
 ////}
-////var enumMember = e./*1*/thirdMember;
+////var enumMember = e.[|/*1*/thirdMember|];
 
 goTo.marker("1");
 verify.goToDefinitionName("thirdMember", "e");
diff --git a/tests/cases/fourslash/docCommentTemplateClassDecl01.ts b/tests/cases/fourslash/docCommentTemplateClassDecl01.ts
index 5a96f20d2e2..342d35a3b4a 100644
--- a/tests/cases/fourslash/docCommentTemplateClassDecl01.ts
+++ b/tests/cases/fourslash/docCommentTemplateClassDecl01.ts
@@ -11,8 +11,5 @@
 ////    }
 ////}
 
-verify.docCommentTemplateAt("decl", /*newTextOffset*/ 8,
-`/**
- * 
- */
-`);
+verify.docCommentTemplateAt("decl", /*newTextOffset*/ 3,
+"/** */");
diff --git a/tests/cases/fourslash/docCommentTemplateClassDeclMethods01.ts b/tests/cases/fourslash/docCommentTemplateClassDeclMethods01.ts
index ef4c82e7df7..2e729243497 100644
--- a/tests/cases/fourslash/docCommentTemplateClassDeclMethods01.ts
+++ b/tests/cases/fourslash/docCommentTemplateClassDeclMethods01.ts
@@ -1,9 +1,7 @@
 /// <reference path='fourslash.ts' />
 
-const enum Indentation {
-    Standard = 8,
-    Indented = 12,
-}
+const singleLineOffset = 3;
+const multiLineOffset = 12;
 
 
 ////class C {
@@ -16,26 +14,22 @@ const enum Indentation {
 ////    }
 ////}
 
-verify.docCommentTemplateAt("0", Indentation.Standard,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("0", singleLineOffset,
+"/** */");
 
 
-verify.docCommentTemplateAt("1", Indentation.Indented,
-   `/**
-     * 
-     */`);
+verify.docCommentTemplateAt("1", singleLineOffset,
+"/** */");
 
 
-verify.docCommentTemplateAt("2", Indentation.Indented,
+verify.docCommentTemplateAt("2", multiLineOffset,
    `/**
      * 
      * @param a
      */
     `);
 
-verify.docCommentTemplateAt("3", Indentation.Indented,
+verify.docCommentTemplateAt("3", multiLineOffset,
    `/**
      * 
      * @param a
@@ -43,7 +37,7 @@ verify.docCommentTemplateAt("3", Indentation.Indented,
      */
     `);
 
-verify.docCommentTemplateAt("4", Indentation.Indented,
+verify.docCommentTemplateAt("4", multiLineOffset,
    `/**
      * 
      * @param a
@@ -51,7 +45,7 @@ verify.docCommentTemplateAt("4", Indentation.Indented,
      * @param param2
      */`);
 
-verify.docCommentTemplateAt("5", Indentation.Indented, 
+verify.docCommentTemplateAt("5", multiLineOffset,
     `/**
      * 
      * @param a
diff --git a/tests/cases/fourslash/docCommentTemplateClassDeclMethods02.ts b/tests/cases/fourslash/docCommentTemplateClassDeclMethods02.ts
index 28da24d381a..7a35e60ae9e 100644
--- a/tests/cases/fourslash/docCommentTemplateClassDeclMethods02.ts
+++ b/tests/cases/fourslash/docCommentTemplateClassDeclMethods02.ts
@@ -1,8 +1,7 @@
 /// <reference path='fourslash.ts' />
 
-const enum Indentation {
-    Indented = 12,
-}
+const singleLineOffset = 3;
+const multiLineOffset = 12;
 
 ////class C {
 ////    /*0*/
@@ -13,12 +12,10 @@ const enum Indentation {
 ////    [1 + 2 + 3 + Math.rand()](x: number, y: string, z = true) { }
 ////}
 
-verify.docCommentTemplateAt("0", Indentation.Indented,
-   `/**
-     * 
-     */`);
+verify.docCommentTemplateAt("0", singleLineOffset,
+"/** */");
 
-verify.docCommentTemplateAt("1", Indentation.Indented,
+verify.docCommentTemplateAt("1", multiLineOffset,
    `/**
      * 
      * @param x
diff --git a/tests/cases/fourslash/docCommentTemplateEmptyFile.ts b/tests/cases/fourslash/docCommentTemplateEmptyFile.ts
index f04653dc328..064306e3fbd 100644
--- a/tests/cases/fourslash/docCommentTemplateEmptyFile.ts
+++ b/tests/cases/fourslash/docCommentTemplateEmptyFile.ts
@@ -3,4 +3,4 @@
 // @Filename: emptyFile.ts
 /////*0*/
 
-verify.noDocCommentTemplateAt("0");
+verify.docCommentTemplateAt("0", 3, "/** */");
diff --git a/tests/cases/fourslash/docCommentTemplateIndentation.ts b/tests/cases/fourslash/docCommentTemplateIndentation.ts
index c3015a6d9dd..bc909aa0265 100644
--- a/tests/cases/fourslash/docCommentTemplateIndentation.ts
+++ b/tests/cases/fourslash/docCommentTemplateIndentation.ts
@@ -5,13 +5,8 @@
 ////    /*1*/
 /////*0*/        function foo() { }
 
-const noIndentEmptyScaffolding = "/**\r\n * \r\n */";
-const oneIndentEmptyScaffolding = "/**\r\n     * \r\n     */";
-const twoIndentEmptyScaffolding = "/**\r\n         * \r\n         */";
-const noIndentOffset = 8;
-const oneIndentOffset = noIndentOffset + 4;
-const twoIndentOffset = oneIndentOffset + 4;
+const singleLineComment = "/** */";
 
-verify.docCommentTemplateAt("0", noIndentOffset, noIndentEmptyScaffolding);
-verify.docCommentTemplateAt("1", oneIndentOffset, oneIndentEmptyScaffolding);
-verify.docCommentTemplateAt("2", twoIndentOffset, twoIndentEmptyScaffolding);
+verify.docCommentTemplateAt("0", 3, singleLineComment);
+verify.docCommentTemplateAt("1", 3, singleLineComment);
+verify.docCommentTemplateAt("2", 3, singleLineComment);
diff --git a/tests/cases/fourslash/docCommentTemplateInsideFunctionDeclaration.ts b/tests/cases/fourslash/docCommentTemplateInsideFunctionDeclaration.ts
index e0ebc00dc39..67a11a27133 100644
--- a/tests/cases/fourslash/docCommentTemplateInsideFunctionDeclaration.ts
+++ b/tests/cases/fourslash/docCommentTemplateInsideFunctionDeclaration.ts
@@ -3,6 +3,10 @@
 // @Filename: functionDecl.ts
 ////f/*0*/unction /*1*/foo/*2*/(/*3*/) /*4*/{ /*5*/}
 
-for (const marker of test.markers()) {
-    verify.noDocCommentTemplateAt(marker);
-}
+verify.noDocCommentTemplateAt("0");
+
+verify.docCommentTemplateAt("1", 3, "/** */");
+verify.docCommentTemplateAt("2", 3, "/** */");
+verify.docCommentTemplateAt("3", 3, "/** */");
+verify.docCommentTemplateAt("4", 3, "/** */");
+verify.docCommentTemplateAt("5", 3, "/** */");
diff --git a/tests/cases/fourslash/docCommentTemplateInterfacesEnumsAndTypeAliases.ts b/tests/cases/fourslash/docCommentTemplateInterfacesEnumsAndTypeAliases.ts
new file mode 100644
index 00000000000..d0805d53255
--- /dev/null
+++ b/tests/cases/fourslash/docCommentTemplateInterfacesEnumsAndTypeAliases.ts
@@ -0,0 +1,49 @@
+/// <reference path='fourslash.ts' />
+
+/////*interfaceFoo*/
+////interface Foo {
+////    /*propertybar*/
+////    bar: any;
+////
+////    /*methodbaz*/
+////    baz(message: any): void;
+////
+////    /*methodUnit*/
+////    unit(): void;
+////}
+////
+/////*enumStatus*/
+////const enum Status {
+////    /*memberOpen*/
+////    Open,
+////
+////    /*memberClosed*/
+////    Closed
+////}
+////
+/////*aliasBar*/
+////type Bar = Foo & any;
+
+verify.docCommentTemplateAt("interfaceFoo", /*expectedOffset*/ 3,
+  "/** */");
+
+verify.docCommentTemplateAt("propertybar", /*expectedOffset*/ 3,
+  "/** */");
+
+verify.docCommentTemplateAt("methodbaz", /*expectedOffset*/ 12,
+   `/**
+     * 
+     * @param message
+     */`);
+
+verify.docCommentTemplateAt("methodUnit", /*expectedOffset*/ 3,
+  "/** */");
+
+verify.docCommentTemplateAt("enumStatus", /*expectedOffset*/ 3,
+  "/** */");
+
+verify.docCommentTemplateAt("memberOpen", /*expectedOffset*/ 3,
+  "/** */");
+
+verify.docCommentTemplateAt("memberClosed", /*expectedOffset*/ 3,
+  "/** */");
\ No newline at end of file
diff --git a/tests/cases/fourslash/docCommentTemplateJSXText.ts b/tests/cases/fourslash/docCommentTemplateJSXText.ts
new file mode 100644
index 00000000000..845f969f4e3
--- /dev/null
+++ b/tests/cases/fourslash/docCommentTemplateJSXText.ts
@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+//@Filename: file.tsx
+////
+//// var x = <div>
+//// /*0*/hello/*1*/
+//// /*2*/goodbye/*3*/
+//// </div>;
+
+for (const marker in test.markers()) {
+    verify.noDocCommentTemplateAt(marker);
+}
\ No newline at end of file
diff --git a/tests/cases/fourslash/docCommentTemplateNamespacesAndModules01.ts b/tests/cases/fourslash/docCommentTemplateNamespacesAndModules01.ts
index e7e52fd5e94..f3ba46605c4 100644
--- a/tests/cases/fourslash/docCommentTemplateNamespacesAndModules01.ts
+++ b/tests/cases/fourslash/docCommentTemplateNamespacesAndModules01.ts
@@ -12,17 +12,11 @@
 ////module "ambientModule" {
 ////}
 
-verify.docCommentTemplateAt("namespaceN", /*indentation*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("namespaceN", /*indentation*/ 3,
+    "/** */");
 
-verify.docCommentTemplateAt("namespaceM", /*indentation*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("namespaceM", /*indentation*/ 3,
+    "/** */");
 
-verify.docCommentTemplateAt("namespaceM", /*indentation*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("namespaceM", /*indentation*/ 3,
+    "/** */");
\ No newline at end of file
diff --git a/tests/cases/fourslash/docCommentTemplateNamespacesAndModules02.ts b/tests/cases/fourslash/docCommentTemplateNamespacesAndModules02.ts
index dad2e9745a9..3beb9368661 100644
--- a/tests/cases/fourslash/docCommentTemplateNamespacesAndModules02.ts
+++ b/tests/cases/fourslash/docCommentTemplateNamespacesAndModules02.ts
@@ -6,11 +6,9 @@
 ////    /*n3*/ n3 {
 ////}
 
-verify.docCommentTemplateAt("top", /*indentation*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("top", /*indentation*/ 3,
+"/** */");
 
-verify.noDocCommentTemplateAt("n2");
+verify.docCommentTemplateAt("n2", 3, "/** */");
 
-verify.noDocCommentTemplateAt("n3");
+verify.docCommentTemplateAt("n3", 3, "/** */");
diff --git a/tests/cases/fourslash/docCommentTemplateObjectLiteralMethods01.ts b/tests/cases/fourslash/docCommentTemplateObjectLiteralMethods01.ts
index 2ae77d4afac..5121957a718 100644
--- a/tests/cases/fourslash/docCommentTemplateObjectLiteralMethods01.ts
+++ b/tests/cases/fourslash/docCommentTemplateObjectLiteralMethods01.ts
@@ -1,8 +1,7 @@
 /// <reference path='fourslash.ts' />
 
-const enum Indentation {
-    Indented = 12,
-}
+const singleLineOffset = 3;
+const multiLineOffset = 12;
 
 ////var x = {
 ////    /*0*/
@@ -13,12 +12,10 @@ const enum Indentation {
 ////    [1 + 2 + 3 + Math.rand()](x: number, y: string, z = true) { }
 ////}
 
-verify.docCommentTemplateAt("0", Indentation.Indented,
-   `/**
-     * 
-     */`);
+verify.docCommentTemplateAt("0", singleLineOffset,
+  "/** */");
 
-verify.docCommentTemplateAt("1", Indentation.Indented,
+verify.docCommentTemplateAt("1", multiLineOffset,
    `/**
      * 
      * @param x
diff --git a/tests/cases/fourslash/docCommentTemplateRegex.ts b/tests/cases/fourslash/docCommentTemplateRegex.ts
index 685c1ca5aef..c1368190ca2 100644
--- a/tests/cases/fourslash/docCommentTemplateRegex.ts
+++ b/tests/cases/fourslash/docCommentTemplateRegex.ts
@@ -3,6 +3,8 @@
 // @Filename: regex.ts
 ////var regex = /*0*///*1*/asdf/*2*/ /*3*///*4*/;
 
-for (const marker of test.markers()) {
-    verify.noDocCommentTemplateAt(marker);
-}
+verify.docCommentTemplateAt("0", 3, "/** */");
+verify.noDocCommentTemplateAt("1");
+verify.noDocCommentTemplateAt("2");
+verify.noDocCommentTemplateAt("3");
+verify.docCommentTemplateAt("4", 3, "/** */");
\ No newline at end of file
diff --git a/tests/cases/fourslash/docCommentTemplateVariableStatements01.ts b/tests/cases/fourslash/docCommentTemplateVariableStatements01.ts
index b6243652167..9112c9a8cab 100644
--- a/tests/cases/fourslash/docCommentTemplateVariableStatements01.ts
+++ b/tests/cases/fourslash/docCommentTemplateVariableStatements01.ts
@@ -29,10 +29,8 @@
 ////}
 
 for (const varName of ["a", "b", "c", "d"]) {
-    verify.docCommentTemplateAt(varName, /*newTextOffset*/ 8,
-`/**
- * 
- */`);
+    verify.docCommentTemplateAt(varName, /*newTextOffset*/ 3,
+        "/** */");
 }
 
 verify.docCommentTemplateAt("e", /*newTextOffset*/ 8,
diff --git a/tests/cases/fourslash/docCommentTemplateVariableStatements02.ts b/tests/cases/fourslash/docCommentTemplateVariableStatements02.ts
index f22e361f63f..8e513780aad 100644
--- a/tests/cases/fourslash/docCommentTemplateVariableStatements02.ts
+++ b/tests/cases/fourslash/docCommentTemplateVariableStatements02.ts
@@ -29,8 +29,6 @@
 ////}, f2 = null;
 
 for (const varName of ["a", "b", "c", "d", "e", "f"]) {
-    verify.docCommentTemplateAt(varName, /*newTextOffset*/ 8,
-`/**
- * 
- */`);
+    verify.docCommentTemplateAt(varName, /*newTextOffset*/ 3,
+        "/** */");
 }
diff --git a/tests/cases/fourslash/docCommentTemplateVariableStatements03.ts b/tests/cases/fourslash/docCommentTemplateVariableStatements03.ts
index 195553098f0..6971b86a312 100644
--- a/tests/cases/fourslash/docCommentTemplateVariableStatements03.ts
+++ b/tests/cases/fourslash/docCommentTemplateVariableStatements03.ts
@@ -49,10 +49,8 @@ verify.docCommentTemplateAt("c", /*newTextOffset*/ 8,
  * @param x
  */`);
 
-verify.docCommentTemplateAt("d", /*newTextOffset*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("d", /*newTextOffset*/ 3,
+"/** */");
 
 verify.docCommentTemplateAt("e", /*newTextOffset*/ 8,
 `/**
@@ -60,10 +58,8 @@ verify.docCommentTemplateAt("e", /*newTextOffset*/ 8,
  * @param param0
  */`);
 
-verify.docCommentTemplateAt("f", /*newTextOffset*/ 8,
-`/**
- * 
- */`);
+verify.docCommentTemplateAt("f", /*newTextOffset*/ 3,
+"/** */");
 
 verify.docCommentTemplateAt("g", /*newTextOffset*/ 8,
 `/**
diff --git a/tests/cases/fourslash/duplicatePackageServices.ts b/tests/cases/fourslash/duplicatePackageServices.ts
index 360611ad140..c84c43cdd9e 100644
--- a/tests/cases/fourslash/duplicatePackageServices.ts
+++ b/tests/cases/fourslash/duplicatePackageServices.ts
@@ -2,7 +2,7 @@
 // @noImplicitReferences: true
 
 // @Filename: /node_modules/a/index.d.ts
-////import /*useAX*/[|{| "isWriteAccess": true, "isDefinition": true |}X|] from "x";
+////import [|{| "name": "useAX", "isWriteAccess": true, "isDefinition": true |}X|] from "x";
 ////export function a(x: [|X|]): void;
 
 // @Filename: /node_modules/a/node_modules/x/index.d.ts
@@ -14,7 +14,7 @@
 ////{ "name": "x", "version": "1.2.3" }
 
 // @Filename: /node_modules/b/index.d.ts
-////import /*useBX*/[|{| "isWriteAccess": true, "isDefinition": true |}X|] from "x";
+////import [|{| "name": "useBX", "isWriteAccess": true, "isDefinition": true |}X|] from "x";
 ////export const b: [|X|];
 
 // @Filename: /node_modules/b/node_modules/x/index.d.ts
diff --git a/tests/cases/fourslash/externalModuleWithExportAssignment.ts b/tests/cases/fourslash/externalModuleWithExportAssignment.ts
index 90009fe9d46..5b392623690 100644
--- a/tests/cases/fourslash/externalModuleWithExportAssignment.ts
+++ b/tests/cases/fourslash/externalModuleWithExportAssignment.ts
@@ -33,8 +33,8 @@ verify.quickInfoAt("1", 'import a1 = require("./externalModuleWithExportAssignme
 verify.quickInfoAt("2", "var a: {\n    (): a1.connectExport;\n    test1: a1.connectModule;\n    test2(): a1.connectModule;\n}", undefined);
 
 goTo.marker('3');
-verify.quickInfoIs("(property) test1: a1.connectModule(res: any, req: any, next: any) => void", undefined);
-verify.completionListContains("test1", "(property) test1: a1.connectModule(res: any, req: any, next: any) => void", undefined);
+verify.quickInfoIs("(property) test1: a1.connectModule\n(res: any, req: any, next: any) => void", undefined);
+verify.completionListContains("test1", "(property) test1: a1.connectModule\n(res: any, req: any, next: any) => void", undefined);
 verify.completionListContains("test2", "(method) test2(): a1.connectModule", undefined);
 verify.not.completionListContains("connectModule");
 verify.not.completionListContains("connectExport");
@@ -53,8 +53,8 @@ verify.currentSignatureHelpIs("a(): a1.connectExport");
 verify.quickInfoAt("8", "var r2: a1.connectExport", undefined);
 
 goTo.marker('9');
-verify.quickInfoIs("(property) test1: a1.connectModule(res: any, req: any, next: any) => void", undefined);
-verify.completionListContains("test1", "(property) test1: a1.connectModule(res: any, req: any, next: any) => void", undefined);
+verify.quickInfoIs("(property) test1: a1.connectModule\n(res: any, req: any, next: any) => void", undefined);
+verify.completionListContains("test1", "(property) test1: a1.connectModule\n(res: any, req: any, next: any) => void", undefined);
 verify.completionListContains("test2", "(method) test2(): a1.connectModule", undefined);
 verify.not.completionListContains("connectModule");
 verify.not.completionListContains("connectExport");
diff --git a/tests/cases/fourslash/extract-method27.ts b/tests/cases/fourslash/extract-method27.ts
new file mode 100644
index 00000000000..a5bb86e2f14
--- /dev/null
+++ b/tests/cases/fourslash/extract-method27.ts
@@ -0,0 +1,34 @@
+/// <reference path='fourslash.ts' />
+
+// Repro https://github.com/Microsoft/TypeScript/issues/19395
+
+// @Filename: test.ts
+//// export const b = 2;
+//// interface Interface { }
+////
+//// async function handle(i: Interface) {
+////     /*a*/const x = 3, y = i;/*b*/
+//// }
+// @Filename: library.d.ts
+//// export as namespace NS;
+//// export const a = 1;
+
+
+goTo.select('a', 'b')
+edit.applyRefactor({
+    refactorName: "Extract Symbol",
+    actionName: "function_scope_1",
+    actionDescription: "Extract to function in module scope",
+    newContent:
+`export const b = 2;
+interface Interface { }
+
+async function handle(i: Interface) {
+    /*RENAME*/newFunction(i);
+}
+
+function newFunction(i: Interface) {
+    const x = 3, y = i;
+}
+`
+});
diff --git a/tests/cases/fourslash/findAllRefsForDefaultExport.ts b/tests/cases/fourslash/findAllRefsForDefaultExport.ts
index 7cd6fe8d57c..414b2503391 100644
--- a/tests/cases/fourslash/findAllRefsForDefaultExport.ts
+++ b/tests/cases/fourslash/findAllRefsForDefaultExport.ts
@@ -5,7 +5,7 @@
 
 // @Filename: b.ts
 ////import [|{| "isWriteAccess": true, "isDefinition": true |}g|] from "./a";
-/////*ref*/[|g|]();
+////[|/*ref*/g|]();
 
 // @Filename: c.ts
 ////import { f } from "./a";
diff --git a/tests/cases/fourslash/fourslash.ts b/tests/cases/fourslash/fourslash.ts
index 1dd1675b513..a0ee392a82e 100644
--- a/tests/cases/fourslash/fourslash.ts
+++ b/tests/cases/fourslash/fourslash.ts
@@ -148,6 +148,7 @@ declare namespace FourSlashInterface {
             kind?: string,
             spanIndex?: number,
             hasAction?: boolean,
+            options?: { includeExternalModuleExports: boolean },
         ): void;
         completionListItemsCountIsGreaterThan(count: number): void;
         completionListIsEmpty(): void;
@@ -221,6 +222,7 @@ declare namespace FourSlashInterface {
          * `verify.goToDefinition("a", ["b", "bb"]);` verifies that "a" has multiple definitions available.
          */
         goToDefinition(startMarkerNames: string | string[], endMarkerNames: string | string[]): void;
+        goToDefinition(startMarkerNames: string | string[], endMarkerNames: string | string[], range: Range): void;
         /** Performs `goToDefinition` for each pair. */
         goToDefinition(startsAndEnds: [string | string[], string | string[]][]): void;
         /** Performs `goToDefinition` on each key and value. */
@@ -296,7 +298,7 @@ declare namespace FourSlashInterface {
         rangesAreDocumentHighlights(ranges?: Range[]): void;
         rangesWithSameTextAreDocumentHighlights(): void;
         documentHighlightsOf(startRange: Range, ranges: Range[]): void;
-        completionEntryDetailIs(entryName: string, text: string, documentation?: string, kind?: string): void;
+        completionEntryDetailIs(entryName: string, text: string, documentation?: string, kind?: string, tags?: ts.JSDocTagInfo[]): void;
         /**
          * This method *requires* a contiguous, complete, and ordered stream of classifications for a file.
          */
diff --git a/tests/cases/fourslash/goToDefinitionAcrossMultipleProjects.ts b/tests/cases/fourslash/goToDefinitionAcrossMultipleProjects.ts
index 7c0565c626a..5447609c027 100644
--- a/tests/cases/fourslash/goToDefinitionAcrossMultipleProjects.ts
+++ b/tests/cases/fourslash/goToDefinitionAcrossMultipleProjects.ts
@@ -9,6 +9,6 @@
 //@Filename: c.ts
 /////// <reference path="a.ts" />
 /////// <reference path="b.ts" />
-/////*use*/x++;
+////[|/*use*/x|]++;
 
 verify.goToDefinition("use", ["def1", "def2"]);
diff --git a/tests/cases/fourslash/goToDefinitionAlias.ts b/tests/cases/fourslash/goToDefinitionAlias.ts
index 22aa049fde3..66afe07b633 100644
--- a/tests/cases/fourslash/goToDefinitionAlias.ts
+++ b/tests/cases/fourslash/goToDefinitionAlias.ts
@@ -7,12 +7,12 @@
 ////}
 ////
 ////// Type position
-////var t1: /*alias1Type*/alias1.IFoo;
-////var t2: Module./*alias2Type*/alias2.IFoo;
+////var t1: [|/*alias1Type*/alias1|].IFoo;
+////var t2: Module.[|/*alias2Type*/alias2|].IFoo;
 ////
 ////// Value posistion
-////var v1 = new /*alias1Value*/alias1.Foo();
-////var v2 = new Module./*alias2Value*/alias2.Foo();
+////var v1 = new [|/*alias1Value*/alias1|].Foo();
+////var v2 = new Module.[|/*alias2Value*/alias2|].Foo();
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionApparentTypeProperties.ts b/tests/cases/fourslash/goToDefinitionApparentTypeProperties.ts
index dd0d91810c4..5d4ec896380 100644
--- a/tests/cases/fourslash/goToDefinitionApparentTypeProperties.ts
+++ b/tests/cases/fourslash/goToDefinitionApparentTypeProperties.ts
@@ -5,7 +5,7 @@
 ////}
 ////
 ////var o = 0;
-////o./*reference1*/myObjectMethod();
-////o["/*reference2*/myObjectMethod"]();
+////o.[|/*reference1*/myObjectMethod|]();
+////o[[|"/*reference2*/myObjectMethod"|]]();
 
 verify.goToDefinition(["reference1", "reference2"], "definition");
diff --git a/tests/cases/fourslash/goToDefinitionConstructorOfClassExpression01.ts b/tests/cases/fourslash/goToDefinitionConstructorOfClassExpression01.ts
index 4b774b8b0ee..b9f17611b18 100644
--- a/tests/cases/fourslash/goToDefinitionConstructorOfClassExpression01.ts
+++ b/tests/cases/fourslash/goToDefinitionConstructorOfClassExpression01.ts
@@ -2,7 +2,7 @@
 
 ////var x = class C {
 ////    /*definition*/constructor() {
-////        var other = new /*usage*/C;
+////        var other = new [|/*usage*/C|];
 ////    }
 ////}
 
diff --git a/tests/cases/fourslash/goToDefinitionConstructorOfClassWhenClassIsPrecededByNamespace01.ts b/tests/cases/fourslash/goToDefinitionConstructorOfClassWhenClassIsPrecededByNamespace01.ts
index bf698c0752d..8f1bc2496dc 100644
--- a/tests/cases/fourslash/goToDefinitionConstructorOfClassWhenClassIsPrecededByNamespace01.ts
+++ b/tests/cases/fourslash/goToDefinitionConstructorOfClassWhenClassIsPrecededByNamespace01.ts
@@ -9,6 +9,6 @@
 ////    }
 ////}
 ////
-////var x = new /*usage*/Foo();
+////var x = new [|/*usage*/Foo|]();
 
 verify.goToDefinition("usage", "definition");
diff --git a/tests/cases/fourslash/goToDefinitionConstructorOverloads.ts b/tests/cases/fourslash/goToDefinitionConstructorOverloads.ts
index a3a5e3286b2..edc9e85d444 100644
--- a/tests/cases/fourslash/goToDefinitionConstructorOverloads.ts
+++ b/tests/cases/fourslash/goToDefinitionConstructorOverloads.ts
@@ -1,13 +1,13 @@
 /// <reference path='fourslash.ts' />
 
 ////class ConstructorOverload {
-////    /*constructorOverload1*/constructor();
+////    [|/*constructorOverload1*/constructor|]();
 ////    /*constructorOverload2*/constructor(foo: string);
 ////    /*constructorDefinition*/constructor(foo: any)  { }
 ////}
 ////
-////var constructorOverload = new /*constructorOverloadReference1*/ConstructorOverload();
-////var constructorOverload = new /*constructorOverloadReference2*/ConstructorOverload("foo");
+////var constructorOverload = new [|/*constructorOverloadReference1*/ConstructorOverload|]();
+////var constructorOverload = new [|/*constructorOverloadReference2*/ConstructorOverload|]("foo");
 
 verify.goToDefinition({
     constructorOverloadReference1: "constructorOverload1",
diff --git a/tests/cases/fourslash/goToDefinitionDecorator.ts b/tests/cases/fourslash/goToDefinitionDecorator.ts
index bef9c8fa5f1..535726aef08 100644
--- a/tests/cases/fourslash/goToDefinitionDecorator.ts
+++ b/tests/cases/fourslash/goToDefinitionDecorator.ts
@@ -1,9 +1,9 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////@/*decoratorUse*/decorator
+////@[|/*decoratorUse*/decorator|]
 ////class C {
-////    @decora/*decoratorFactoryUse*/torFactory(a, "22", true)
+////    @[|decora/*decoratorFactoryUse*/torFactory|](a, "22", true)
 ////    method() {}
 ////}
 
diff --git a/tests/cases/fourslash/goToDefinitionDecoratorOverloads.ts b/tests/cases/fourslash/goToDefinitionDecoratorOverloads.ts
index 965c8bbbc6d..4943c23e392 100644
--- a/tests/cases/fourslash/goToDefinitionDecoratorOverloads.ts
+++ b/tests/cases/fourslash/goToDefinitionDecoratorOverloads.ts
@@ -9,8 +9,8 @@
 ////
 ////declare const s: symbol;
 ////class C {
-////    @/*useDecString*/dec f() {}
-////    @/*useDecSymbol*/dec [s]() {}
+////    @[|/*useDecString*/dec|] f() {}
+////    @[|/*useDecSymbol*/dec|] [s]() {}
 ////}
 
 verify.goToDefinition({
diff --git a/tests/cases/fourslash/goToDefinitionDynamicImport1.ts b/tests/cases/fourslash/goToDefinitionDynamicImport1.ts
index 2e93534496a..d85ba12d725 100644
--- a/tests/cases/fourslash/goToDefinitionDynamicImport1.ts
+++ b/tests/cases/fourslash/goToDefinitionDynamicImport1.ts
@@ -3,8 +3,8 @@
 // @Filename: foo.ts
 //// /*Destination*/export function foo() { return "foo"; }
 
-//// import("./f/*1*/oo")
-//// var x = import("./fo/*2*/o")
+//// import([|"./f/*1*/oo"|])
+//// var x = import([|"./fo/*2*/o"|])
 
 verify.goToDefinition("1", "Destination");
 verify.goToDefinition("2", "Destination");
\ No newline at end of file
diff --git a/tests/cases/fourslash/goToDefinitionDynamicImport2.ts b/tests/cases/fourslash/goToDefinitionDynamicImport2.ts
index c3c213a6cdb..678628d641f 100644
--- a/tests/cases/fourslash/goToDefinitionDynamicImport2.ts
+++ b/tests/cases/fourslash/goToDefinitionDynamicImport2.ts
@@ -5,7 +5,7 @@
 
 //// var x = import("./foo");
 //// x.then(foo => {
-////     foo.b/*1*/ar(); 
+////     foo.[|b/*1*/ar|](); 
 //// })
 
 verify.goToDefinition("1", "Destination");
\ No newline at end of file
diff --git a/tests/cases/fourslash/goToDefinitionDynamicImport3.ts b/tests/cases/fourslash/goToDefinitionDynamicImport3.ts
index f8c5962f984..dc63696d62a 100644
--- a/tests/cases/fourslash/goToDefinitionDynamicImport3.ts
+++ b/tests/cases/fourslash/goToDefinitionDynamicImport3.ts
@@ -3,6 +3,6 @@
 // @Filename: foo.ts
 //// export function /*Destination*/bar() { return "bar"; }
 
-//// import('./foo').then(({ ba/*1*/r }) => undefined);
+//// import('./foo').then(({ [|ba/*1*/r|] }) => undefined);
 
 verify.goToDefinition("1", "Destination");
\ No newline at end of file
diff --git a/tests/cases/fourslash/goToDefinitionDynamicImport4.ts b/tests/cases/fourslash/goToDefinitionDynamicImport4.ts
index f8c5962f984..dc63696d62a 100644
--- a/tests/cases/fourslash/goToDefinitionDynamicImport4.ts
+++ b/tests/cases/fourslash/goToDefinitionDynamicImport4.ts
@@ -3,6 +3,6 @@
 // @Filename: foo.ts
 //// export function /*Destination*/bar() { return "bar"; }
 
-//// import('./foo').then(({ ba/*1*/r }) => undefined);
+//// import('./foo').then(({ [|ba/*1*/r|] }) => undefined);
 
 verify.goToDefinition("1", "Destination");
\ No newline at end of file
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName.ts
index 705cdd65583..f91d8a9e346 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import n = require('./a/*1*/');
+////import n = require([|'./a/*1*/'|]);
 ////var x = new n.Foo();
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName2.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName2.ts
index 866d21b3632..913b297feb8 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName2.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName2.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import n = require('./a/*1*/');
+////import n = require([|'./a/*1*/'|]);
 ////var x = new n.Foo();
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName3.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName3.ts
index 7ac0376474d..d6e28263239 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName3.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName3.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import n = require('e/*1*/');
+////import n = require([|'e/*1*/'|]);
 ////var x = new n.Foo();
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName5.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName5.ts
index 36ae9dd716f..9dede44a7bc 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName5.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName5.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: a.ts
-////declare module /*2*/"external/*1*/" {
+////declare module /*2*/[|"external/*1*/"|] {
 ////    class Foo { }
 ////}
 
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName6.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName6.ts
index a71030628e6..51b96cfe3ba 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName6.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName6.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import * from 'e/*1*/';
+////import * from [|'e/*1*/'|];
 
 // @Filename: a.ts
 ////declare module /*2*/"e" {
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName7.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName7.ts
index b025944d012..591577bf470 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName7.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName7.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////import {Foo, Bar} from 'e/*1*/';
+////import {Foo, Bar} from [|'e/*1*/'|];
 
 // @Filename: a.ts
 ////declare module /*2*/"e" {
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName8.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName8.ts
index ca9d7c83e66..636c234c79e 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName8.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName8.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////export {Foo, Bar} from 'e/*1*/';
+////export {Foo, Bar} from [|'e/*1*/'|];
 
 // @Filename: a.ts
 ////declare module /*2*/"e" {
diff --git a/tests/cases/fourslash/goToDefinitionExternalModuleName9.ts b/tests/cases/fourslash/goToDefinitionExternalModuleName9.ts
index 80971be100f..60decba626c 100644
--- a/tests/cases/fourslash/goToDefinitionExternalModuleName9.ts
+++ b/tests/cases/fourslash/goToDefinitionExternalModuleName9.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 // @Filename: b.ts
-////export * from 'e/*1*/';
+////export * from [|'e/*1*/'|];
 
 // @Filename: a.ts
 ////declare module /*2*/"e" {
diff --git a/tests/cases/fourslash/goToDefinitionFunctionOverloads.ts b/tests/cases/fourslash/goToDefinitionFunctionOverloads.ts
index 60c7a8111ee..ca3883be86c 100644
--- a/tests/cases/fourslash/goToDefinitionFunctionOverloads.ts
+++ b/tests/cases/fourslash/goToDefinitionFunctionOverloads.ts
@@ -1,12 +1,12 @@
 /// <reference path='fourslash.ts' />
 
-////function /*functionOverload1*/functionOverload(value: number);
+////function [|/*functionOverload1*/functionOverload|](value: number);
 ////function /*functionOverload2*/functionOverload(value: string);
 ////function /*functionOverloadDefinition*/functionOverload() {}
 ////
-/////*functionOverloadReference1*/functionOverload(123);
-/////*functionOverloadReference2*/functionOverload("123");
-/////*brokenOverload*/functionOverload({});
+////[|/*functionOverloadReference1*/functionOverload|](123);
+////[|/*functionOverloadReference2*/functionOverload|]("123");
+////[|/*brokenOverload*/functionOverload|]({});
 
 verify.goToDefinition({
     functionOverloadReference1: "functionOverload1",
diff --git a/tests/cases/fourslash/goToDefinitionFunctionOverloadsInClass.ts b/tests/cases/fourslash/goToDefinitionFunctionOverloadsInClass.ts
index 04017123fd8..08ec93b5eea 100644
--- a/tests/cases/fourslash/goToDefinitionFunctionOverloadsInClass.ts
+++ b/tests/cases/fourslash/goToDefinitionFunctionOverloadsInClass.ts
@@ -2,9 +2,9 @@
 
 ////class clsInOverload {
 ////    static fnOverload();
-////    static /*staticFunctionOverload*/fnOverload(foo: string);
+////    static [|/*staticFunctionOverload*/fnOverload|](foo: string);
 ////    static /*staticFunctionOverloadDefinition*/fnOverload(foo: any) { }
-////    public /*functionOverload*/fnOverload(): any;
+////    public [|/*functionOverload*/fnOverload|](): any;
 ////    public fnOverload(foo: string);
 ////    public /*functionOverloadDefinition*/fnOverload(foo: any) { return "foo" }
 ////
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames.ts b/tests/cases/fourslash/goToDefinitionImportedNames.ts
index 41a1c443b28..c525783b9c2 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////export {/*classAliasDefinition*/Class} from "./a";
+////export {[|/*classAliasDefinition*/Class|]} from "./a";
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames2.ts b/tests/cases/fourslash/goToDefinitionImportedNames2.ts
index fa3c5c862b7..58a5d018eef 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames2.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames2.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////import {/*classAliasDefinition*/Class} from "./a";
+////import {[|/*classAliasDefinition*/Class|]} from "./a";
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames3.ts b/tests/cases/fourslash/goToDefinitionImportedNames3.ts
index b9f598f30cd..ea52f660c11 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames3.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames3.ts
@@ -1,8 +1,8 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: e.ts
-//// import {M, /*classAliasDefinition*/C, I} from "./d";
-//// var c = new /*classReference*/C();
+//// import {M, [|/*classAliasDefinition*/C|], I} from "./d";
+//// var c = new [|/*classReference*/C|]();
 
 
 // @Filename: d.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames4.ts b/tests/cases/fourslash/goToDefinitionImportedNames4.ts
index 81f2e671266..435ab41a2ad 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames4.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames4.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////import {Class as /*classAliasDefinition*/ClassAlias} from "./a";
+////import {Class as [|/*classAliasDefinition*/ClassAlias|]} from "./a";
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames5.ts b/tests/cases/fourslash/goToDefinitionImportedNames5.ts
index b78110c95d9..7965b341d9e 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames5.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames5.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////export {Class as /*classAliasDefinition*/ClassAlias} from "./a";
+////export {Class as [|/*classAliasDefinition*/ClassAlias|]} from "./a";
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames6.ts b/tests/cases/fourslash/goToDefinitionImportedNames6.ts
index 21603cded42..a8acf33e42a 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames6.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames6.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////import /*moduleAliasDefinition*/alias = require("./a");
+////import [|/*moduleAliasDefinition*/alias|] = require("./a");
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImportedNames7.ts b/tests/cases/fourslash/goToDefinitionImportedNames7.ts
index bdf1eff86eb..d798dcfff0c 100644
--- a/tests/cases/fourslash/goToDefinitionImportedNames7.ts
+++ b/tests/cases/fourslash/goToDefinitionImportedNames7.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 // @Filename: b.ts
-////import /*classAliasDefinition*/defaultExport from "./a";
+////import [|/*classAliasDefinition*/defaultExport|] from "./a";
 
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/goToDefinitionImports.ts b/tests/cases/fourslash/goToDefinitionImports.ts
index 4fdaedb5c3d..1debd3c6b6f 100644
--- a/tests/cases/fourslash/goToDefinitionImports.ts
+++ b/tests/cases/fourslash/goToDefinitionImports.ts
@@ -12,10 +12,10 @@
 ////import f, { x } from "./a";
 ////import * as /*aDef*/a from "./a";
 ////import b = require("./b");
-/////*fUse*/f;
-/////*xUse*/x;
-/////*aUse*/a;
-/////*bUse*/b;
+////[|/*fUse*/f|];
+////[|/*xUse*/x|];
+////[|/*aUse*/a|];
+////[|/*bUse*/b|];
 
 verify.goToDefinition({
     aUse: "aDef", // Namespace import isn't "skipped"
diff --git a/tests/cases/fourslash/goToDefinitionInMemberDeclaration.ts b/tests/cases/fourslash/goToDefinitionInMemberDeclaration.ts
index 93be2086440..4a09a931bf6 100644
--- a/tests/cases/fourslash/goToDefinitionInMemberDeclaration.ts
+++ b/tests/cases/fourslash/goToDefinitionInMemberDeclaration.ts
@@ -9,13 +9,13 @@
 ////enum /*enumDefinition*/Enum { value1, value2 };
 ////
 ////class /*selfDefinition*/Bar {
-////    public _interface: IFo/*interfaceReference*/o = new Fo/*classReferenceInInitializer*/o();
-////    public _class: Fo/*classReference*/o = new Foo();
-////    public _list: IF/*interfaceReferenceInList*/oo[]=[];
-////    public _enum: E/*enumReference*/num = En/*enumReferenceInInitializer*/um.value1;
-////    public _self: Ba/*selfReference*/r;
+////    public _interface: [|IFo/*interfaceReference*/o|] = new [|Fo/*classReferenceInInitializer*/o|]();
+////    public _class: [|Fo/*classReference*/o|] = new Foo();
+////    public _list: [|IF/*interfaceReferenceInList*/oo|][]=[];
+////    public _enum: [|E/*enumReference*/num|] = [|En/*enumReferenceInInitializer*/um|].value1;
+////    public _self: [|Ba/*selfReference*/r|];
 ////
-////    constructor(public _inConstructor: IFo/*interfaceReferenceInConstructor*/o) {
+////    constructor(public _inConstructor: [|IFo/*interfaceReferenceInConstructor*/o|]) {
 ////    }
 ////}
 
diff --git a/tests/cases/fourslash/goToDefinitionJsModuleName.ts b/tests/cases/fourslash/goToDefinitionJsModuleName.ts
index cdd322158f7..8514e7070e4 100644
--- a/tests/cases/fourslash/goToDefinitionJsModuleName.ts
+++ b/tests/cases/fourslash/goToDefinitionJsModuleName.ts
@@ -5,6 +5,6 @@
 /////*2*/module.exports = {};
 
 // @Filename: bar.js
-////var x = require(/*1*/"./foo");
+////var x = require([|/*1*/"./foo"|]);
 
 verify.goToDefinition("1", "2");
diff --git a/tests/cases/fourslash/goToDefinitionLabels.ts b/tests/cases/fourslash/goToDefinitionLabels.ts
index 5cbf3ac8f2f..3736d9207ee 100644
--- a/tests/cases/fourslash/goToDefinitionLabels.ts
+++ b/tests/cases/fourslash/goToDefinitionLabels.ts
@@ -2,9 +2,9 @@
 
 /////*label1Definition*/label1: while (true) {
 ////    /*label2Definition*/label2: while (true) {
-////        break /*1*/label1;
-////        continue /*2*/label2;
-////        () => { break /*3*/label1; }
+////        break [|/*1*/label1|];
+////        continue [|/*2*/label2|];
+////        () => { break [|/*3*/label1|]; }
 ////        continue /*4*/unknownLabel;
 ////    }
 ////}
diff --git a/tests/cases/fourslash/goToDefinitionMethodOverloads.ts b/tests/cases/fourslash/goToDefinitionMethodOverloads.ts
index 4dfe4753ce7..fa67b5dbef5 100644
--- a/tests/cases/fourslash/goToDefinitionMethodOverloads.ts
+++ b/tests/cases/fourslash/goToDefinitionMethodOverloads.ts
@@ -1,22 +1,22 @@
 /// <reference path='fourslash.ts' />
 
 ////class MethodOverload {
-////    static /*staticMethodOverload1*/method();
+////    static [|/*staticMethodOverload1*/method|]();
 ////    static /*staticMethodOverload2*/method(foo: string);
 ////    static /*staticMethodDefinition*/method(foo?: any) { }
-////    public /*instanceMethodOverload1*/method(): any;
+////    public [|/*instanceMethodOverload1*/method|](): any;
 ////    public /*instanceMethodOverload2*/method(foo: string);
 ////    public /*instanceMethodDefinition*/method(foo?: any) { return "foo" }
 ////}
 
 ////// static method
-////MethodOverload./*staticMethodReference1*/method();
-////MethodOverload./*staticMethodReference2*/method("123");
+////MethodOverload.[|/*staticMethodReference1*/method|]();
+////MethodOverload.[|/*staticMethodReference2*/method|]("123");
 
 ////// instance method
 ////var methodOverload = new MethodOverload();
-////methodOverload./*instanceMethodReference1*/method();
-////methodOverload./*instanceMethodReference2*/method("456");
+////methodOverload.[|/*instanceMethodReference1*/method|]();
+////methodOverload.[|/*instanceMethodReference2*/method|]("456");
 
 verify.goToDefinition({
     staticMethodReference1: "staticMethodOverload1",
diff --git a/tests/cases/fourslash/goToDefinitionMultipleDefinitions.ts b/tests/cases/fourslash/goToDefinitionMultipleDefinitions.ts
index fb022f7711f..99b6d32e7f3 100644
--- a/tests/cases/fourslash/goToDefinitionMultipleDefinitions.ts
+++ b/tests/cases/fourslash/goToDefinitionMultipleDefinitions.ts
@@ -14,7 +14,7 @@
 ////    instance3: number;
 ////}
 ////
-////var ifoo: IFo/*interfaceReference*/o;
+////var ifoo: [|IFo/*interfaceReference*/o|];
 
 verify.goToDefinition("interfaceReference", ["interfaceDefinition1", "interfaceDefinition2", "interfaceDefinition3"]);
 
@@ -29,6 +29,6 @@ verify.goToDefinition("interfaceReference", ["interfaceDefinition1", "interfaceD
 ////}
 
 // @Filename: e.ts
-////Modul/*moduleReference*/e;
+////[|Modul/*moduleReference*/e|];
 
 verify.goToDefinition("moduleReference", ["moduleDefinition1", "moduleDefinition2"]);
diff --git a/tests/cases/fourslash/goToDefinitionObjectBindingElementPropertyName01.ts b/tests/cases/fourslash/goToDefinitionObjectBindingElementPropertyName01.ts
index 32b08ab710d..1bcae727971 100644
--- a/tests/cases/fourslash/goToDefinitionObjectBindingElementPropertyName01.ts
+++ b/tests/cases/fourslash/goToDefinitionObjectBindingElementPropertyName01.ts
@@ -6,6 +6,6 @@
 ////}
 ////
 ////var foo: I;
-////var { /*use*/property1: prop1 } = foo;
+////var { [|/*use*/property1|]: prop1 } = foo;
 
 verify.goToDefinition("use", "def");
diff --git a/tests/cases/fourslash/goToDefinitionObjectLiteralProperties1.ts b/tests/cases/fourslash/goToDefinitionObjectLiteralProperties1.ts
index a1c22ca4ca3..0024682dc71 100644
--- a/tests/cases/fourslash/goToDefinitionObjectLiteralProperties1.ts
+++ b/tests/cases/fourslash/goToDefinitionObjectLiteralProperties1.ts
@@ -5,11 +5,11 @@
 //// }
 //// function foo(arg: PropsBag) {}
 //// foo({
-////    pr/*p1*/opx: 10
+////    [|pr/*p1*/opx|]: 10
 //// })
 //// function bar(firstarg: boolean, secondarg: PropsBag) {}
 //// bar(true, {
-////    pr/*p2*/opx: 10
+////    [|pr/*p2*/opx|]: 10
 //// })
 
 
diff --git a/tests/cases/fourslash/goToDefinitionObjectSpread.ts b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
index b23d0a80448..918fa555f86 100644
--- a/tests/cases/fourslash/goToDefinitionObjectSpread.ts
+++ b/tests/cases/fourslash/goToDefinitionObjectSpread.ts
@@ -5,5 +5,5 @@
 ////let a1: A1;
 ////let a2: A2;
 ////let a12 = { ...a1, ...a2 };
-////a12.a/*3*/;
+////a12.[|a/*3*/|];
 verify.goToDefinition('3', [ '1', '2' ]);
diff --git a/tests/cases/fourslash/goToDefinitionOverloadsInMultiplePropertyAccesses.ts b/tests/cases/fourslash/goToDefinitionOverloadsInMultiplePropertyAccesses.ts
index 04a07f41a7f..9898b6dad1e 100644
--- a/tests/cases/fourslash/goToDefinitionOverloadsInMultiplePropertyAccesses.ts
+++ b/tests/cases/fourslash/goToDefinitionOverloadsInMultiplePropertyAccesses.ts
@@ -9,6 +9,6 @@
 ////        export function f(value: number | string) {}
 ////    }
 ////}
-////A.B./*2*/f("");
+////A.B.[|/*2*/f|]("");
 
 verify.goToDefinition("2", "1");
diff --git a/tests/cases/fourslash/goToDefinitionPartialImplementation.ts b/tests/cases/fourslash/goToDefinitionPartialImplementation.ts
index 81f19b578ed..00cf6fd1819 100644
--- a/tests/cases/fourslash/goToDefinitionPartialImplementation.ts
+++ b/tests/cases/fourslash/goToDefinitionPartialImplementation.ts
@@ -13,7 +13,7 @@
 ////        x: number;
 ////    }
 ////
-////    var x: /*Part2Use*/IA;
+////    var x: [|/*Part2Use*/IA|];
 ////}
 
 verify.goToDefinition("Part2Use", ["Part1Definition", "Part2Definition"]);
diff --git a/tests/cases/fourslash/goToDefinitionRest.ts b/tests/cases/fourslash/goToDefinitionRest.ts
index 1459b9ffa88..2577aafb625 100644
--- a/tests/cases/fourslash/goToDefinitionRest.ts
+++ b/tests/cases/fourslash/goToDefinitionRest.ts
@@ -7,6 +7,6 @@
 ////}
 ////let t: Gen;
 ////var { x, ...rest } = t;
-////rest./*2*/parent;
+////rest.[|/*2*/parent|];
 const ranges = test.ranges();
 verify.goToDefinition('2', [ '1' ]);
diff --git a/tests/cases/fourslash/goToDefinitionShorthandProperty01.ts b/tests/cases/fourslash/goToDefinitionShorthandProperty01.ts
index 4107049286c..7e46894d244 100644
--- a/tests/cases/fourslash/goToDefinitionShorthandProperty01.ts
+++ b/tests/cases/fourslash/goToDefinitionShorthandProperty01.ts
@@ -3,9 +3,9 @@
 //// var /*valueDeclaration1*/name = "hello";
 //// var /*valueDeclaration2*/id = 100000;
 //// declare var /*valueDeclaration3*/id;
-//// var obj = {/*valueDefinition1*/name, /*valueDefinition2*/id};
-//// obj./*valueReference1*/name;
-//// obj./*valueReference2*/id;
+//// var obj = {[|/*valueDefinition1*/name|], [|/*valueDefinition2*/id|]};
+//// obj.[|/*valueReference1*/name|];
+//// obj.[|/*valueReference2*/id|];
 
 verify.goToDefinition({
     valueDefinition1: "valueDeclaration1",
diff --git a/tests/cases/fourslash/goToDefinitionShorthandProperty02.ts b/tests/cases/fourslash/goToDefinitionShorthandProperty02.ts
index 0ecdcacdcd6..1d78ade4267 100644
--- a/tests/cases/fourslash/goToDefinitionShorthandProperty02.ts
+++ b/tests/cases/fourslash/goToDefinitionShorthandProperty02.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 ////let x = {
-////    f/*1*/oo
+////    [|f/*1*/oo|]
 ////}
 
 verify.goToDefinition("1", []);
diff --git a/tests/cases/fourslash/goToDefinitionShorthandProperty03.ts b/tests/cases/fourslash/goToDefinitionShorthandProperty03.ts
index 42a9ee0a4d6..3a04d3efa06 100644
--- a/tests/cases/fourslash/goToDefinitionShorthandProperty03.ts
+++ b/tests/cases/fourslash/goToDefinitionShorthandProperty03.ts
@@ -1,10 +1,10 @@
 /// <reference path='fourslash.ts' />
 
 ////var /*varDef*/x = {
-////    /*varProp*/x
+////    [|/*varProp*/x|]
 ////}
 ////let /*letDef*/y = {
-////    /*letProp*/y
+////    [|/*letProp*/y|]
 ////}
 
 verify.goToDefinition({
diff --git a/tests/cases/fourslash/goToDefinitionSimple.ts b/tests/cases/fourslash/goToDefinitionSimple.ts
index 9ae02f26bf2..3d1cdd632ba 100644
--- a/tests/cases/fourslash/goToDefinitionSimple.ts
+++ b/tests/cases/fourslash/goToDefinitionSimple.ts
@@ -4,7 +4,7 @@
 ////class /*2*/c { }
 
 // @Filename: Consumption.ts
-//// var n = new /*1*/c();
-//// var n = new c/*3*/();
+//// var n = new [|/*1*/c|]();
+//// var n = new [|c/*3*/|]();
 
 verify.goToDefinition(["1", "3"], "2");
diff --git a/tests/cases/fourslash/goToDefinitionSourceUnit.ts b/tests/cases/fourslash/goToDefinitionSourceUnit.ts
index e66b5ef7960..d823b366eee 100644
--- a/tests/cases/fourslash/goToDefinitionSourceUnit.ts
+++ b/tests/cases/fourslash/goToDefinitionSourceUnit.ts
@@ -4,7 +4,7 @@
 //// //MyFile Comments
 //// //more comments
 //// /// <reference path="so/*unknownFile*/mePath.ts" />
-//// /// <reference path="b/*knownFile*/.ts" />
+//// /// <reference path="[|b/*knownFile*/.ts|]" />
 ////
 //// class clsInOverload {
 ////     static fnOverload();
diff --git a/tests/cases/fourslash/goToDefinitionTaggedTemplateOverloads.ts b/tests/cases/fourslash/goToDefinitionTaggedTemplateOverloads.ts
index b01bace4feb..fcb28f86d05 100644
--- a/tests/cases/fourslash/goToDefinitionTaggedTemplateOverloads.ts
+++ b/tests/cases/fourslash/goToDefinitionTaggedTemplateOverloads.ts
@@ -4,8 +4,8 @@
 ////function /*defFBool*/f(strs: TemplateStringsArray, x: boolean): void;
 ////function f(strs: TemplateStringsArray, x: number | boolean) {}
 ////
-/////*useFNumber*/f`${0}`;
-/////*useFBool*/f`${false}`;
+////[|/*useFNumber*/f|]`${0}`;
+////[|/*useFBool*/f|]`${false}`;
 
 verify.goToDefinition({
     useFNumber: "defFNumber",
diff --git a/tests/cases/fourslash/goToDefinitionThis.ts b/tests/cases/fourslash/goToDefinitionThis.ts
index 923fb6c8feb..88cbcb8ca96 100644
--- a/tests/cases/fourslash/goToDefinitionThis.ts
+++ b/tests/cases/fourslash/goToDefinitionThis.ts
@@ -1,11 +1,11 @@
 /// <reference path='fourslash.ts'/>
 
 ////function f(/*fnDecl*/this: number) {
-////    return /*fnUse*/this;
+////    return [|/*fnUse*/this|];
 ////}
 ////class /*cls*/C {
-////    constructor() { return /*clsUse*/this; }
-////    get self(/*getterDecl*/this: number) { return /*getterUse*/this; }
+////    constructor() { return [|/*clsUse*/this|]; }
+////    get self(/*getterDecl*/this: number) { return [|/*getterUse*/this|]; }
 ////}
 
 verify.goToDefinition({
diff --git a/tests/cases/fourslash/goToDefinitionTypePredicate.ts b/tests/cases/fourslash/goToDefinitionTypePredicate.ts
index 17e6fc1be6b..9988611885c 100644
--- a/tests/cases/fourslash/goToDefinitionTypePredicate.ts
+++ b/tests/cases/fourslash/goToDefinitionTypePredicate.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts'/>
 
 //// class /*classDeclaration*/A {}
-//// function f(/*parameterDeclaration*/parameter: any): /*parameterName*/parameter is /*typeReference*/A {
+//// function f(/*parameterDeclaration*/parameter: any): [|/*parameterName*/parameter|] is [|/*typeReference*/A|] {
 ////     return typeof parameter === "string";
 //// }
 
diff --git a/tests/cases/fourslash/goToDefinitionTypeReferenceDirective.ts b/tests/cases/fourslash/goToDefinitionTypeReferenceDirective.ts
index ad02bb9d851..532390fb35e 100644
--- a/tests/cases/fourslash/goToDefinitionTypeReferenceDirective.ts
+++ b/tests/cases/fourslash/goToDefinitionTypeReferenceDirective.ts
@@ -5,7 +5,7 @@
 /////*0*/declare let $: {x: number};
 
 // @Filename: src/app.ts
-//// /// <reference types="lib/*1*/"/>
+//// /// <reference types="[|lib/*1*/|]"/>
 //// $.x;
 
 verify.goToDefinition("1", "0");
diff --git a/tests/cases/fourslash/goToDefinitionUnionTypeProperty1.ts b/tests/cases/fourslash/goToDefinitionUnionTypeProperty1.ts
index 82bd07e32f0..6baca39e011 100644
--- a/tests/cases/fourslash/goToDefinitionUnionTypeProperty1.ts
+++ b/tests/cases/fourslash/goToDefinitionUnionTypeProperty1.ts
@@ -12,7 +12,7 @@
 ////
 ////var x : One | Two;
 ////
-////x./*propertyReference*/commonProperty;
+////x.[|/*propertyReference*/commonProperty|];
 ////x./*3*/commonFunction;
 
 verify.goToDefinition("propertyReference", ["propertyDefinition1", "propertyDefinition2"]);
diff --git a/tests/cases/fourslash/goToDefinitionUnionTypeProperty2.ts b/tests/cases/fourslash/goToDefinitionUnionTypeProperty2.ts
index 22ffb906e8e..3ade25ca622 100644
--- a/tests/cases/fourslash/goToDefinitionUnionTypeProperty2.ts
+++ b/tests/cases/fourslash/goToDefinitionUnionTypeProperty2.ts
@@ -14,6 +14,6 @@
 ////
 ////var x : One | Two;
 ////
-////x.common./*propertyReference*/a;
+////x.common.[|/*propertyReference*/a|];
 
 verify.goToDefinition("propertyReference", ["propertyDefinition2", "propertyDefinition1"]);
diff --git a/tests/cases/fourslash/goToDefinitionUnionTypeProperty3.ts b/tests/cases/fourslash/goToDefinitionUnionTypeProperty3.ts
index fde4d2319fe..3f5666f19b8 100644
--- a/tests/cases/fourslash/goToDefinitionUnionTypeProperty3.ts
+++ b/tests/cases/fourslash/goToDefinitionUnionTypeProperty3.ts
@@ -7,6 +7,6 @@
 ////var strings: string[];
 ////var numbers: number[];
 ////
-////var x = (strings || numbers)./*usage*/specialPop()
+////var x = (strings || numbers).[|/*usage*/specialPop|]()
 
 verify.goToDefinition("usage", "definition");
diff --git a/tests/cases/fourslash/goToDefinitionUnionTypeProperty4.ts b/tests/cases/fourslash/goToDefinitionUnionTypeProperty4.ts
index f69554098c5..a4c59961592 100644
--- a/tests/cases/fourslash/goToDefinitionUnionTypeProperty4.ts
+++ b/tests/cases/fourslash/goToDefinitionUnionTypeProperty4.ts
@@ -16,6 +16,6 @@
 ////var magnitude: Magnitude;
 ////var snapcrackle: SnapCrackle;
 ////
-////var x = (snapcrackle || magnitude || art)./*usage*/pop;
+////var x = (snapcrackle || magnitude || art).[|/*usage*/pop|];
 
 verify.goToDefinition("usage", ["def1", "def2", "def3"]);
diff --git a/tests/cases/fourslash/goToDefinition_super.ts b/tests/cases/fourslash/goToDefinition_super.ts
index 115e4a4a6ed..22f00aff7dc 100644
--- a/tests/cases/fourslash/goToDefinition_super.ts
+++ b/tests/cases/fourslash/goToDefinition_super.ts
@@ -7,10 +7,10 @@
 ////class /*B*/B extends A {}
 ////class C extends B {
 ////    constructor() {
-////        /*super*/super();
+////        [|/*super*/super|]();
 ////    }
 ////    method() {
-////        /*superExpression*/super.x();
+////        [|/*superExpression*/super|].x();
 ////    }
 ////}
 ////class D {
diff --git a/tests/cases/fourslash/goToDefinition_untypedModule.ts b/tests/cases/fourslash/goToDefinition_untypedModule.ts
index fe29f7104cf..8c9e83711a9 100644
--- a/tests/cases/fourslash/goToDefinition_untypedModule.ts
+++ b/tests/cases/fourslash/goToDefinition_untypedModule.ts
@@ -5,6 +5,6 @@
 
 // @Filename: /a.ts
 ////import { /*def*/f } from "foo";
-/////*use*/f();
+////[|/*use*/f|]();
 
 verify.goToDefinition("use", "def");
diff --git a/tests/cases/fourslash/goToModuleAliasDefinition.ts b/tests/cases/fourslash/goToModuleAliasDefinition.ts
index dfccc3393c5..98724228a6e 100644
--- a/tests/cases/fourslash/goToModuleAliasDefinition.ts
+++ b/tests/cases/fourslash/goToModuleAliasDefinition.ts
@@ -5,7 +5,7 @@
 
 // @Filename: b.ts
 //// import /*3*/n = require('a');
-//// var x = new /*1*/n.Foo();
+//// var x = new [|/*1*/n|].Foo();
 
 // Won't-fixed: Should go to '2' instead
 verify.goToDefinition("1", "3");
diff --git a/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern1.ts b/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern1.ts
index 98c06c06d7b..dcc5a977be5 100644
--- a/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern1.ts
+++ b/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern1.ts
@@ -7,6 +7,6 @@
 //// interface Test {
 ////   /*destination*/prop2: number
 //// }
-//// bar<Test>(({pr/*goto*/op2})=>{});
+//// bar<Test>(({[|pr/*goto*/op2|]})=>{});
 
 verify.goToDefinition("goto", "destination");
\ No newline at end of file
diff --git a/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern2.ts b/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern2.ts
index 9e41f646c46..6d513d6abee 100644
--- a/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern2.ts
+++ b/tests/cases/fourslash/gotoDefinitionInObjectBindingPattern2.ts
@@ -1,7 +1,7 @@
 /// <reference path='fourslash.ts' />
 
 //// var p0 = ({a/*1*/a}) => {console.log(aa)};
-//// function f2({ a/*a1*/1, b/*b1*/1 }: { /*a1_dest*/a1: number, /*b1_dest*/b1: number } = { a1: 0, b1: 0 }) {}
+//// function f2({ [|a/*a1*/1|], [|b/*b1*/1|] }: { /*a1_dest*/a1: number, /*b1_dest*/b1: number } = { a1: 0, b1: 0 }) {}
 
 verify.goToDefinition("1", []);
 verify.goToDefinition("a1", "a1_dest");
diff --git a/tests/cases/fourslash/gotoDefinitionPropertyAccessExpressionHeritageClause.ts b/tests/cases/fourslash/gotoDefinitionPropertyAccessExpressionHeritageClause.ts
index d46ea7c8422..3d58d869c49 100644
--- a/tests/cases/fourslash/gotoDefinitionPropertyAccessExpressionHeritageClause.ts
+++ b/tests/cases/fourslash/gotoDefinitionPropertyAccessExpressionHeritageClause.ts
@@ -4,7 +4,7 @@
 //// function foo() {
 ////     return {/*refB*/B: B};
 //// }
-//// class C extends (foo())./*B*/B {}
-//// class C1 extends foo()./*B1*/B {}
+//// class C extends (foo()).[|/*B*/B|] {}
+//// class C1 extends foo().[|/*B1*/B|] {}
 
 verify.goToDefinition([["B", "refB"], ["B1", "refB"]]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports0.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports0.ts
new file mode 100644
index 00000000000..3b62e0e9d5f
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports0.ts
@@ -0,0 +1,18 @@
+/// <reference path="fourslash.ts" />
+// @AllowSyntheticDefaultImports: true
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import bar from "./foo";
+
+export var x = 0;
+bar();`
+  ]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports1.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports1.ts
new file mode 100644
index 00000000000..c6c2a554874
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports1.ts
@@ -0,0 +1,18 @@
+/// <reference path="fourslash.ts" />
+// @Module: system
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import bar from "./foo";
+
+export var x = 0;
+bar();`
+]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports2.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports2.ts
new file mode 100644
index 00000000000..f6ba985715e
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports2.ts
@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+// @AllowSyntheticDefaultImports: false
+// @Module: system
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import * as bar from "./foo";
+
+export var x = 0;
+bar();`
+]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports3.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports3.ts
new file mode 100644
index 00000000000..bc0ba6d8163
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports3.ts
@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+// @AllowSyntheticDefaultImports: false
+// @Module: commonjs
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import bar = require("./foo");
+
+export var x = 0;
+bar();`
+]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports4.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports4.ts
new file mode 100644
index 00000000000..c8ce87db71a
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports4.ts
@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+// @AllowSyntheticDefaultImports: false
+// @Module: amd
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import bar = require("./foo");
+
+export var x = 0;
+bar();`
+]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports5.ts b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports5.ts
new file mode 100644
index 00000000000..7830faaacc8
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFixNewImportAllowSyntheticDefaultImports5.ts
@@ -0,0 +1,19 @@
+/// <reference path="fourslash.ts" />
+// @AllowSyntheticDefaultImports: false
+// @Module: umd
+
+// @Filename: a/f1.ts
+//// [|export var x = 0;
+//// bar/*0*/();|]
+
+// @Filename: a/foo.d.ts
+//// declare function bar(): number;
+//// export = bar;
+//// export as namespace bar;
+
+verify.importFixAtPosition([
+`import bar = require("./foo");
+
+export var x = 0;
+bar();`
+]);
\ No newline at end of file
diff --git a/tests/cases/fourslash/importNameCodeFixUMDGlobal0.ts b/tests/cases/fourslash/importNameCodeFixUMDGlobal0.ts
index 3c780dc0af6..3208a41bba1 100644
--- a/tests/cases/fourslash/importNameCodeFixUMDGlobal0.ts
+++ b/tests/cases/fourslash/importNameCodeFixUMDGlobal0.ts
@@ -1,5 +1,8 @@
 /// <reference path="fourslash.ts" />
 
+// @AllowSyntheticDefaultImports: false
+// @Module: es2015
+
 // @Filename: a/f1.ts
 //// [|export function test() { };
 //// bar1/*0*/.bar;|]
diff --git a/tests/cases/fourslash/importNameCodeFixUMDGlobal1.ts b/tests/cases/fourslash/importNameCodeFixUMDGlobal1.ts
index 96671ad6f91..1beebb0477c 100644
--- a/tests/cases/fourslash/importNameCodeFixUMDGlobal1.ts
+++ b/tests/cases/fourslash/importNameCodeFixUMDGlobal1.ts
@@ -1,5 +1,8 @@
 /// <reference path="fourslash.ts" />
 
+// @AllowSyntheticDefaultImports: false
+// @Module: esnext
+
 // @Filename: a/f1.ts
 //// [|import { bar } from "./foo";
 ////
diff --git a/tests/cases/fourslash/importNameCodeFixUMDGlobalReact0.ts b/tests/cases/fourslash/importNameCodeFixUMDGlobalReact0.ts
index 260c34d10a6..5b6df7a5173 100644
--- a/tests/cases/fourslash/importNameCodeFixUMDGlobalReact0.ts
+++ b/tests/cases/fourslash/importNameCodeFixUMDGlobalReact0.ts
@@ -1,6 +1,8 @@
 /// <reference path="fourslash.ts" />
 
 // @jsx: react
+// @allowSyntheticDefaultImports: false
+// @module: es2015
 
 // @Filename: /node_modules/@types/react/index.d.ts
 ////export = React;
diff --git a/tests/cases/fourslash/importNameCodeFixUMDGlobalReact1.ts b/tests/cases/fourslash/importNameCodeFixUMDGlobalReact1.ts
index ccd69c50199..669db55342b 100644
--- a/tests/cases/fourslash/importNameCodeFixUMDGlobalReact1.ts
+++ b/tests/cases/fourslash/importNameCodeFixUMDGlobalReact1.ts
@@ -1,6 +1,8 @@
 /// <reference path="fourslash.ts" />
 
 // @jsx: react
+// @allowSyntheticDefaultImports: false
+// @module: es2015
 
 // @Filename: /node_modules/@types/react/index.d.ts
 ////export = React;
diff --git a/tests/cases/fourslash/incrementalParsingDynamicImport1.ts b/tests/cases/fourslash/incrementalParsingDynamicImport1.ts
index 0f15dcb3b1b..511f3835f5b 100644
--- a/tests/cases/fourslash/incrementalParsingDynamicImport1.ts
+++ b/tests/cases/fourslash/incrementalParsingDynamicImport1.ts
@@ -7,11 +7,11 @@
 
 //// var x1 = import("./foo");
 //// x1.then(foo => {
-////    var s: string = foo.bar();    
+////    var s: string = foo.bar();
 //// })
 //// /*1*/
 
-verify.numberOfErrorsInCurrentFile(1);
+verify.numberOfErrorsInCurrentFile(2);
 goTo.marker("1");
 edit.insert("  ");
-verify.numberOfErrorsInCurrentFile(1);
\ No newline at end of file
+verify.numberOfErrorsInCurrentFile(2);
\ No newline at end of file
diff --git a/tests/cases/fourslash/incrementalParsingDynamicImport3.ts b/tests/cases/fourslash/incrementalParsingDynamicImport3.ts
index b3da4c5b538..64aca403ad9 100644
--- a/tests/cases/fourslash/incrementalParsingDynamicImport3.ts
+++ b/tests/cases/fourslash/incrementalParsingDynamicImport3.ts
@@ -11,4 +11,4 @@
 verify.numberOfErrorsInCurrentFile(0);
 goTo.marker("1");
 edit.insert("(");
-verify.numberOfErrorsInCurrentFile(2);
\ No newline at end of file
+verify.numberOfErrorsInCurrentFile(3);
\ No newline at end of file
diff --git a/tests/cases/fourslash/indentationInJsx3.ts b/tests/cases/fourslash/indentationInJsx3.ts
new file mode 100644
index 00000000000..0c57b3b31e4
--- /dev/null
+++ b/tests/cases/fourslash/indentationInJsx3.ts
@@ -0,0 +1,35 @@
+/// <reference path='fourslash.ts' />
+
+//@Filename: file.tsx
+////function foo() {
+////   return (
+////        <div>
+////hello
+////goodbye
+////        </div>
+////    )
+////}
+
+verify.currentFileContentIs(
+`function foo() {
+   return (
+        <div>
+hello
+goodbye
+        </div>
+    )
+}`
+);
+
+format.document();
+
+verify.currentFileContentIs(
+`function foo() {
+    return (
+        <div>
+            hello
+            goodbye
+        </div>
+    )
+}`
+);
\ No newline at end of file
diff --git a/tests/cases/fourslash/javaScriptClass3.ts b/tests/cases/fourslash/javaScriptClass3.ts
index fd67f6f53a5..60f51b4ac79 100644
--- a/tests/cases/fourslash/javaScriptClass3.ts
+++ b/tests/cases/fourslash/javaScriptClass3.ts
@@ -12,8 +12,8 @@
 ////    method() { return this.alpha; }
 //// }
 //// var x = new Foo();
-//// x.alpha/*src1*/;
-//// x.beta/*src2*/;
+//// x.[|alpha/*src1*/|];
+//// x.[|beta/*src2*/|];
 
 verify.goToDefinition({
     src1: "dst1",
diff --git a/tests/cases/fourslash/jsDocInheritDoc.ts b/tests/cases/fourslash/jsDocInheritDoc.ts
new file mode 100644
index 00000000000..8a19bd0c14e
--- /dev/null
+++ b/tests/cases/fourslash/jsDocInheritDoc.ts
@@ -0,0 +1,57 @@
+///<reference path="fourslash.ts" />
+// @Filename: inheritDoc.ts
+////class Foo {
+////    /**
+////     * Foo constructor documentation
+////     */
+////    constructor(value: number) {}
+////    /**
+////     * Foo#method1 documentation
+////     */
+////    static method1() {}
+////    /**
+////     * Foo#method2 documentation
+////     */
+////    method2() {}
+////    /**
+////     * Foo#property1 documentation
+////     */
+////    property1: string;
+////}
+////interface Baz {
+////    /** Baz#property1 documentation */
+////    property1: string;
+////    /**
+////     * Baz#property2 documentation
+////     */
+////    property2: object;
+////}
+////class Bar extends Foo implements Baz {
+////    ctorValue: number;
+////    /** @inheritDoc */
+////    constructor(value: number) {
+////        super(value);
+////        this.ctorValue = value;
+////    }
+////    /** @inheritDoc */
+////    static method1() {}
+////    method2() {}
+////    /** @inheritDoc */
+////    property1: string;
+////    /**
+////     * Bar#property2
+////     * @inheritDoc
+////     */
+////    property2: object;
+////}
+////const b = new Bar/*1*/(5);
+////b.method2/*2*/();
+////Bar.method1/*3*/();
+////const p1 = b.property1/*4*/;
+////const p2 = b.property2/*5*/;
+
+verify.quickInfoAt("1", "constructor Bar(value: number): Bar", undefined); // constructors aren't actually inherited
+verify.quickInfoAt("2", "(method) Bar.method2(): void", "Foo#method2 documentation"); // use inherited docs only
+verify.quickInfoAt("3", "(method) Bar.method1(): void", undefined); // statics aren't actually inherited
+verify.quickInfoAt("4", "(property) Bar.property1: string", "Foo#property1 documentation"); // use inherited docs only
+verify.quickInfoAt("5", "(property) Bar.property2: object", "Baz#property2 documentation\nBar#property2"); // include local and inherited docs
diff --git a/tests/cases/fourslash/jsDocTags.ts b/tests/cases/fourslash/jsDocTags.ts
index dbcb7c2d8f7..368939ecbfc 100644
--- a/tests/cases/fourslash/jsDocTags.ts
+++ b/tests/cases/fourslash/jsDocTags.ts
@@ -26,20 +26,20 @@
 ////     /**
 ////      * @mytag1 some comments
 ////      * some more comments about mytag1
-////      * @mytag2 
+////      * @mytag2
 ////      * here all the comments are on a new line
-////      * @mytag3 
+////      * @mytag3
 ////      * @mytag
 ////      */
 ////     property2: number;
-////     /** 
+////     /**
 ////      * @returns {number} a value
 ////      */
 ////     method3(): number { return 3; }
 ////     /**
 ////      * @param {string} foo A value.
 ////      * @returns {number} Another value
-////      * @mytag 
+////      * @mytag
 ////      */
 ////     method4(foo: string): number { return 3; }
 ////     /** @mytag */
@@ -69,7 +69,12 @@ verify.currentSignatureHelpTagsAre([{name: "mytag", text:"comment1 comment2"}])
 goTo.marker("12");
 verify.currentSignatureHelpTagsAre([{name: "mytag", text:""}])
 goTo.marker("13");
-verify.currentSignatureHelpTagsAre([])
+verify.currentSignatureHelpTagsAre([{ name: "returns", text: "a value" }])
 
 goTo.marker('14');
-verify.completionEntryDetailIs("newMethod", "(method) Foo.newMethod(): void", "method documentation", "method", [{name: "mytag", text: "a JSDoc tag"}]);
\ No newline at end of file
+verify.completionEntryDetailIs(
+    "newMethod",
+    "(method) Foo.newMethod(): void",
+    "method documentation",
+    "method",
+    [{name: "mytag", text: "a JSDoc tag"}]);
diff --git a/tests/cases/fourslash/jsdocTypedefTagServices.ts b/tests/cases/fourslash/jsdocTypedefTagServices.ts
index c97707e4d25..e4b262c3ee4 100644
--- a/tests/cases/fourslash/jsdocTypedefTagServices.ts
+++ b/tests/cases/fourslash/jsdocTypedefTagServices.ts
@@ -10,7 +10,7 @@
 //// */
 
 /////**
-//// * @type {/*use*/[|Product|]}
+//// * @type {[|/*use*/Product|]}
 //// */
 ////const product = null;
 
diff --git a/tests/cases/fourslash/quickInfoFunctionKeyword.ts b/tests/cases/fourslash/quickInfoFunctionKeyword.ts
new file mode 100644
index 00000000000..d593aa679d4
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoFunctionKeyword.ts
@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts'/>
+
+////[1].forEach(fu/*1*/nction() {});
+////[1].map(x =/*2*/> x + 1);
+
+verify.quickInfoAt("1", "(local function)(): void");
+verify.quickInfoAt("2", "function(x: number): number");
diff --git a/tests/cases/fourslash/quickInfoInvalidLocations.ts b/tests/cases/fourslash/quickInfoInvalidLocations.ts
index c70be23f387..396fac67c97 100644
--- a/tests/cases/fourslash/quickInfoInvalidLocations.ts
+++ b/tests/cases/fourslash/quickInfoInvalidLocations.ts
@@ -1,35 +1,35 @@
 /// <reference path='fourslash.ts' />
 
 
-////inter/*invlaid1*/face IFoo {
+////inter/*invalid1*/face IFoo {
 ////    new(): IFoo;
 ////    [indexer: string]: number;
 ////    method(value: number): string;
 ////    property: string;
-/////*invlaid2*/}
+/////*invalid2*/}
 ////
-////cl/*invlaid3*/ass bar imple/*invlaid4*/ments IFoo {
-////    constructor(   /*invlaid5*/  ) {
+////cl/*invalid3*/ass bar imple/*invalid4*/ments IFoo {
+////    constructor(   /*invalid5*/  ) {
 ////
 ////    }
 ////
-////    pu/*invlaid6*/blic method(value: string): string {
-////        retu/*invlaid7*/rn null;
+////    pu/*invalid6*/blic method(value: string): string {
+////        retu/*invalid7*/rn null;
 ////    }
 ////
-////    public property: string  /*invlaid8*/= "string";
+////    public property: string  /*invalid8*/= "string";
 ////
-////    public ge/*invlaid9*/t value() {
+////    public ge/*invalid9*/t value() {
 ////        return 0;
 ////    }
 ////}
 ////
 ////
-////mod/*invlaid10*/ule m1 {
-////    va/*invlaid11*/r varibale = 0;
+////mod/*invalid10*/ule m1 {
+////    va/*invalid11*/r varibale = 0;
 ////
-////    func/*invlaid12*/tion foo(arg1: number) {
-////        ret/*invlaid13*/urn string;
+////    function foo(arg1: number) {
+////        ret/*invalid13*/urn string;
 ////    }
 ////
 ////    class foo {
@@ -40,7 +40,7 @@
 ////        value1: "string",
 ////        value2: {
 ////            value21: number
-////        /*invlaid14*/}
+////        /*invalid14*/}
 ////    };
 ////}
 
diff --git a/tests/cases/fourslash/quickInfoJsDocTags.ts b/tests/cases/fourslash/quickInfoJsDocTags.ts
new file mode 100644
index 00000000000..ce045ab2940
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoJsDocTags.ts
@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts'/>
+
+// @Filename: quickInfoJsDocTags.ts
+/////**
+//// * Doc
+//// * @author Me
+//// * @augments {C<T>} Augments it
+//// * @template {T} A template
+//// * @type {number | string} A type
+//// * @typedef {number | string} NumOrStr
+//// * @property {number} x The prop
+//// * @param {number} x The param
+//// * @returns The result
+//// */
+////function /**/foo(x) {}
+
+verify.baselineQuickInfo();
diff --git a/tests/cases/fourslash/refactorUseDefaultImport.ts b/tests/cases/fourslash/refactorUseDefaultImport.ts
new file mode 100644
index 00000000000..8834b70f85e
--- /dev/null
+++ b/tests/cases/fourslash/refactorUseDefaultImport.ts
@@ -0,0 +1,29 @@
+/// <reference path='fourslash.ts' />
+
+// @allowSyntheticDefaultImports: true
+
+// @Filename: /a.d.ts
+////declare const x: number;
+////export = x;
+
+// @Filename: /b.ts
+/////*b0*/import * as a from "./a";/*b1*/
+
+// @Filename: /c.ts
+/////*c0*/import a = require("./a");/*c1*/
+
+goTo.select("b0", "b1");
+edit.applyRefactor({
+    refactorName: "Convert to default import",
+    actionName: "Convert to default import",
+    actionDescription: "Convert to default import",
+    newContent: 'import a from "./a";',
+});
+
+goTo.select("c0", "c1");
+edit.applyRefactor({
+    refactorName: "Convert to default import",
+    actionName: "Convert to default import",
+    actionDescription: "Convert to default import",
+    newContent: 'import a from "./a";',
+});
diff --git a/tests/cases/fourslash/server/definition01.ts b/tests/cases/fourslash/server/definition01.ts
index 7889d185fcd..70921b72ed4 100644
--- a/tests/cases/fourslash/server/definition01.ts
+++ b/tests/cases/fourslash/server/definition01.ts
@@ -1,7 +1,7 @@
 /// <reference path="../fourslash.ts"/>
 
 // @Filename: b.ts
-////import n = require('./a/*1*/');
+////import n = require([|'./a/*1*/'|]);
 ////var x = new n.Foo();
 
 // @Filename: a.ts
diff --git a/tests/cases/fourslash/server/jsdocTypedefTagGoToDefinition.ts b/tests/cases/fourslash/server/jsdocTypedefTagGoToDefinition.ts
index 000adef9081..dd72fdd42ad 100644
--- a/tests/cases/fourslash/server/jsdocTypedefTagGoToDefinition.ts
+++ b/tests/cases/fourslash/server/jsdocTypedefTagGoToDefinition.ts
@@ -14,10 +14,10 @@
 ////  */
 ////
 //// /** @type {Person} */
-//// var person; person.personName/*3*/
+//// var person; person.[|personName/*3*/|]
 ////
 //// /** @type {Animal} */
-//// var animal; animal.animalName/*4*/
+//// var animal; animal.[|animalName/*4*/|]
 
 verify.goToDefinition({
     3: "1",
diff --git a/tests/cases/fourslash/shims-pp/goToDefinitionTypeReferenceDirective.ts b/tests/cases/fourslash/shims-pp/goToDefinitionTypeReferenceDirective.ts
index ad02bb9d851..532390fb35e 100644
--- a/tests/cases/fourslash/shims-pp/goToDefinitionTypeReferenceDirective.ts
+++ b/tests/cases/fourslash/shims-pp/goToDefinitionTypeReferenceDirective.ts
@@ -5,7 +5,7 @@
 /////*0*/declare let $: {x: number};
 
 // @Filename: src/app.ts
-//// /// <reference types="lib/*1*/"/>
+//// /// <reference types="[|lib/*1*/|]"/>
 //// $.x;
 
 verify.goToDefinition("1", "0");
diff --git a/tests/cases/fourslash/shims/goToDefinitionTypeReferenceDirective.ts b/tests/cases/fourslash/shims/goToDefinitionTypeReferenceDirective.ts
index 4669b7f62e9..f318de7c25e 100644
--- a/tests/cases/fourslash/shims/goToDefinitionTypeReferenceDirective.ts
+++ b/tests/cases/fourslash/shims/goToDefinitionTypeReferenceDirective.ts
@@ -5,7 +5,7 @@
 /////*0*/declare let $: {x: number};
 
 // @Filename: src/app.ts
-//// /// <reference types="lib/*1*/"/>
+//// /// <reference types="[|lib/*1*/|]"/>
 //// $.x;
 
 verify.goToDefinition("1", "0");
diff --git a/tests/cases/fourslash/tsxGoToDefinitionClasses.ts b/tests/cases/fourslash/tsxGoToDefinitionClasses.ts
index 688ce879adf..f0b58155bf5 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionClasses.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionClasses.ts
@@ -11,9 +11,9 @@
 ////         /*pt*/foo: string;
 ////     }
 //// }
-//// var x = <My/*c*/Class />;
-//// var y = <MyClass f/*p*/oo= 'hello' />;
-//// var z = <MyCl/*w*/ass wrong= 'hello' />;
+//// var x = <[|My/*c*/Class|] />;
+//// var y = <MyClass [|f/*p*/oo|]= 'hello' />;
+//// var z = <[|MyCl/*w*/ass|] wrong= 'hello' />;
 
 verify.goToDefinition({
     c: "ct",
diff --git a/tests/cases/fourslash/tsxGoToDefinitionIntrinsics.ts b/tests/cases/fourslash/tsxGoToDefinitionIntrinsics.ts
index a82e813baa7..9b202a64c21 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionIntrinsics.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionIntrinsics.ts
@@ -11,9 +11,9 @@
 ////         /*st*/span: { n: string; };
 ////     }
 //// }
-//// var x = <di/*ds*/v />;
-//// var y = <s/*ss*/pan />;
-//// var z = <div na/*ps*/me='hello' />;
+//// var x = <[|di/*ds*/v|] />;
+//// var y = <[|s/*ss*/pan|] />;
+//// var z = <div [|na/*ps*/me|]='hello' />;
 
 verify.goToDefinition({
     ds: "dt",
diff --git a/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction1.ts b/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction1.ts
index d620b3585af..6ef0e93445f 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction1.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction1.ts
@@ -16,10 +16,10 @@
 ////     /*pt2*/optional?: boolean
 //// }
 //// declare function /*opt*/Opt(attributes: OptionPropBag): JSX.Element;
-//// let opt = <O/*one*/pt />;
-//// let opt1 = <Op/*two*/t pr/*p1*/opx={100} />;
-//// let opt2 = <Op/*three*/t propx={100} opt/*p2*/ional />;
-//// let opt3 = <Op/*four*/t wr/*p3*/ong />;
+//// let opt = <[|O/*one*/pt|] />;
+//// let opt1 = <[|Op/*two*/t|] [|pr/*p1*/opx|]={100} />;
+//// let opt2 = <[|Op/*three*/t|] propx={100} [|opt/*p2*/ional|] />;
+//// let opt3 = <[|Op/*four*/t|] wr/*p3*/ong />;
 
 verify.goToDefinition({
     one: "opt",
diff --git a/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction2.ts b/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction2.ts
index 17737983230..9d5efe2442b 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction2.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionStatelessFunction2.ts
@@ -23,12 +23,12 @@
 //// declare function /*firstSource*/MainButton(buttonProps: ButtonProps): JSX.Element;
 //// declare function /*secondSource*/MainButton(linkProps: LinkProps): JSX.Element;
 //// declare function /*thirdSource*/MainButton(props: ButtonProps | LinkProps): JSX.Element;
-//// let opt = <Main/*firstTarget*/Button />;
-//// let opt = <Main/*secondTarget*/Button children="chidlren" />;
-//// let opt = <Main/*thirdTarget*/Button onClick={()=>{}} />;
-//// let opt = <Main/*fourthTarget*/Button onClick={()=>{}} ignore-prop />;
-//// let opt = <Main/*fivethTarget*/Button goTo="goTo" />;
-//// let opt = <Main/*sixthTarget*/Button wrong />;
+//// let opt = <[|Main/*firstTarget*/Button|] />;
+//// let opt = <[|Main/*secondTarget*/Button|] children="chidlren" />;
+//// let opt = <[|Main/*thirdTarget*/Button|] onClick={()=>{}} />;
+//// let opt = <[|Main/*fourthTarget*/Button|] onClick={()=>{}} ignore-prop />;
+//// let opt = <[|Main/*fivethTarget*/Button|] goTo="goTo" />;
+//// let opt = <[|Main/*sixthTarget*/Button|] wrong />;
 
 verify.goToDefinition({
     firstTarget: "thirdSource",
diff --git a/tests/cases/fourslash/tsxGoToDefinitionUnionElementType1.ts b/tests/cases/fourslash/tsxGoToDefinitionUnionElementType1.ts
index db78f46f3ad..d6b5dfab709 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionUnionElementType1.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionUnionElementType1.ts
@@ -19,7 +19,7 @@
 //// }
 
 //// var SFCComp = SFC1 || SFC2;
-//// <SFC/*one*/Comp x />
+//// <[|SFC/*one*/Comp|] x />
 
 verify.goToDefinition({
     "one": "pt1"
diff --git a/tests/cases/fourslash/tsxGoToDefinitionUnionElementType2.ts b/tests/cases/fourslash/tsxGoToDefinitionUnionElementType2.ts
index 75ca81998a0..548ce94db5a 100644
--- a/tests/cases/fourslash/tsxGoToDefinitionUnionElementType2.ts
+++ b/tests/cases/fourslash/tsxGoToDefinitionUnionElementType2.ts
@@ -19,7 +19,7 @@
 
 //// var /*pt1*/RCComp = RC1 || RC2;
 
-//// <RC/*one*/Comp />
+//// <[|RC/*one*/Comp|] />
 
 verify.goToDefinition({
     "one": "pt1"
diff --git a/tests/cases/user/ajv/index.ts b/tests/cases/user/ajv/index.ts
new file mode 100644
index 00000000000..ffcbd04e944
--- /dev/null
+++ b/tests/cases/user/ajv/index.ts
@@ -0,0 +1 @@
+import ajv = require("ajv");
diff --git a/tests/cases/user/ajv/package.json b/tests/cases/user/ajv/package.json
new file mode 100644
index 00000000000..72782496ab0
--- /dev/null
+++ b/tests/cases/user/ajv/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "ajv-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "ajv": "latest"
+  }
+}
diff --git a/tests/cases/user/ajv/tsconfig.json b/tests/cases/user/ajv/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/ajv/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/antd/index.ts b/tests/cases/user/antd/index.ts
new file mode 100644
index 00000000000..edc6fcfb52e
--- /dev/null
+++ b/tests/cases/user/antd/index.ts
@@ -0,0 +1 @@
+import antd = require("antd");
diff --git a/tests/cases/user/antd/package.json b/tests/cases/user/antd/package.json
new file mode 100644
index 00000000000..a20168dd27b
--- /dev/null
+++ b/tests/cases/user/antd/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "antd-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@types/react": "^16.0.18",
+    "antd": "latest"
+  }
+}
diff --git a/tests/cases/user/antd/tsconfig.json b/tests/cases/user/antd/tsconfig.json
new file mode 100644
index 00000000000..adbd65f2d00
--- /dev/null
+++ b/tests/cases/user/antd/tsconfig.json
@@ -0,0 +1,8 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": [],
+        "allowSyntheticDefaultImports": true
+    }
+}
diff --git a/tests/cases/user/axios/index.ts b/tests/cases/user/axios/index.ts
new file mode 100644
index 00000000000..43a4bf8d5d0
--- /dev/null
+++ b/tests/cases/user/axios/index.ts
@@ -0,0 +1 @@
+import axios = require("axios");
diff --git a/tests/cases/user/axios/package.json b/tests/cases/user/axios/package.json
new file mode 100644
index 00000000000..b4cc25a9b97
--- /dev/null
+++ b/tests/cases/user/axios/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "axios-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "axios": "latest"
+  }
+}
diff --git a/tests/cases/user/axios/tsconfig.json b/tests/cases/user/axios/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/axios/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/bignumber.js/index.ts b/tests/cases/user/bignumber.js/index.ts
new file mode 100644
index 00000000000..fbbbc4c0661
--- /dev/null
+++ b/tests/cases/user/bignumber.js/index.ts
@@ -0,0 +1 @@
+import bignumber_js = require("bignumber.js");
diff --git a/tests/cases/user/bignumber.js/package.json b/tests/cases/user/bignumber.js/package.json
new file mode 100644
index 00000000000..8b5fea49297
--- /dev/null
+++ b/tests/cases/user/bignumber.js/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "bignumber.js-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "bignumber.js": "latest"
+  }
+}
diff --git a/tests/cases/user/bignumber.js/tsconfig.json b/tests/cases/user/bignumber.js/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/bignumber.js/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/discord.js/index.ts b/tests/cases/user/discord.js/index.ts
new file mode 100644
index 00000000000..e86cef98fb0
--- /dev/null
+++ b/tests/cases/user/discord.js/index.ts
@@ -0,0 +1 @@
+import discord_js = require("discord.js");
diff --git a/tests/cases/user/discord.js/package.json b/tests/cases/user/discord.js/package.json
new file mode 100644
index 00000000000..c78d4cd0645
--- /dev/null
+++ b/tests/cases/user/discord.js/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "discord.js-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@types/node": "^8.0.47",
+    "discord.js": "latest"
+  }
+}
diff --git a/tests/cases/user/discord.js/tsconfig.json b/tests/cases/user/discord.js/tsconfig.json
new file mode 100644
index 00000000000..a8a84f5c5fe
--- /dev/null
+++ b/tests/cases/user/discord.js/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": ["node"]
+    }
+}
diff --git a/tests/cases/user/electron/index.ts b/tests/cases/user/electron/index.ts
new file mode 100644
index 00000000000..c8af4b993ff
--- /dev/null
+++ b/tests/cases/user/electron/index.ts
@@ -0,0 +1 @@
+import electron = require("electron");
diff --git a/tests/cases/user/electron/package.json b/tests/cases/user/electron/package.json
new file mode 100644
index 00000000000..3113f8bd03b
--- /dev/null
+++ b/tests/cases/user/electron/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "electron-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "electron": "latest"
+  }
+}
diff --git a/tests/cases/user/electron/tsconfig.json b/tests/cases/user/electron/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/electron/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/eventemitter2/index.ts b/tests/cases/user/eventemitter2/index.ts
new file mode 100644
index 00000000000..c68cae71e50
--- /dev/null
+++ b/tests/cases/user/eventemitter2/index.ts
@@ -0,0 +1 @@
+import eventemitter2 = require("eventemitter2");
diff --git a/tests/cases/user/eventemitter2/package.json b/tests/cases/user/eventemitter2/package.json
new file mode 100644
index 00000000000..7a1fb9e04f8
--- /dev/null
+++ b/tests/cases/user/eventemitter2/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "eventemitter2-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "eventemitter2": "latest"
+  }
+}
diff --git a/tests/cases/user/eventemitter2/tsconfig.json b/tests/cases/user/eventemitter2/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/eventemitter2/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/eventemitter3/index.ts b/tests/cases/user/eventemitter3/index.ts
new file mode 100644
index 00000000000..1ef33830f09
--- /dev/null
+++ b/tests/cases/user/eventemitter3/index.ts
@@ -0,0 +1 @@
+import eventemitter3 = require("eventemitter3");
diff --git a/tests/cases/user/eventemitter3/package.json b/tests/cases/user/eventemitter3/package.json
new file mode 100644
index 00000000000..7b401395c6a
--- /dev/null
+++ b/tests/cases/user/eventemitter3/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "eventemitter3-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "eventemitter3": "latest"
+  }
+}
diff --git a/tests/cases/user/eventemitter3/tsconfig.json b/tests/cases/user/eventemitter3/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/eventemitter3/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/firebase/index.ts b/tests/cases/user/firebase/index.ts
new file mode 100644
index 00000000000..dfd40bf009d
--- /dev/null
+++ b/tests/cases/user/firebase/index.ts
@@ -0,0 +1 @@
+import firebase = require("firebase");
diff --git a/tests/cases/user/firebase/package.json b/tests/cases/user/firebase/package.json
new file mode 100644
index 00000000000..11fb1d2ea7e
--- /dev/null
+++ b/tests/cases/user/firebase/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "firebase-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "firebase": "latest"
+  }
+}
diff --git a/tests/cases/user/firebase/tsconfig.json b/tests/cases/user/firebase/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/firebase/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/github/index.ts b/tests/cases/user/github/index.ts
new file mode 100644
index 00000000000..90e2253381c
--- /dev/null
+++ b/tests/cases/user/github/index.ts
@@ -0,0 +1 @@
+import github = require("github");
diff --git a/tests/cases/user/github/package.json b/tests/cases/user/github/package.json
new file mode 100644
index 00000000000..37a0181865f
--- /dev/null
+++ b/tests/cases/user/github/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "github-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "github": "latest"
+  }
+}
diff --git a/tests/cases/user/github/tsconfig.json b/tests/cases/user/github/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/github/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/immutable/index.ts b/tests/cases/user/immutable/index.ts
new file mode 100644
index 00000000000..b5fb927e459
--- /dev/null
+++ b/tests/cases/user/immutable/index.ts
@@ -0,0 +1 @@
+import immutable = require("immutable");
diff --git a/tests/cases/user/immutable/package.json b/tests/cases/user/immutable/package.json
new file mode 100644
index 00000000000..fb869e488ea
--- /dev/null
+++ b/tests/cases/user/immutable/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "immutable-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "immutable": "latest"
+  }
+}
diff --git a/tests/cases/user/immutable/tsconfig.json b/tests/cases/user/immutable/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/immutable/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/isobject/index.ts b/tests/cases/user/isobject/index.ts
new file mode 100644
index 00000000000..92b08ff4825
--- /dev/null
+++ b/tests/cases/user/isobject/index.ts
@@ -0,0 +1 @@
+import isobject = require("isobject");
diff --git a/tests/cases/user/isobject/package.json b/tests/cases/user/isobject/package.json
new file mode 100644
index 00000000000..b1501180526
--- /dev/null
+++ b/tests/cases/user/isobject/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "isobject-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "isobject": "latest"
+  }
+}
diff --git a/tests/cases/user/isobject/tsconfig.json b/tests/cases/user/isobject/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/isobject/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/jimp/index.ts b/tests/cases/user/jimp/index.ts
new file mode 100644
index 00000000000..6a7d51414aa
--- /dev/null
+++ b/tests/cases/user/jimp/index.ts
@@ -0,0 +1 @@
+import jimp = require("jimp");
diff --git a/tests/cases/user/jimp/package.json b/tests/cases/user/jimp/package.json
new file mode 100644
index 00000000000..18ebc2933e3
--- /dev/null
+++ b/tests/cases/user/jimp/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "jimp-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "jimp": "latest"
+  }
+}
diff --git a/tests/cases/user/jimp/tsconfig.json b/tests/cases/user/jimp/tsconfig.json
new file mode 100644
index 00000000000..a8a84f5c5fe
--- /dev/null
+++ b/tests/cases/user/jimp/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": ["node"]
+    }
+}
diff --git a/tests/cases/user/jsonschema/index.ts b/tests/cases/user/jsonschema/index.ts
new file mode 100644
index 00000000000..0cab63413a5
--- /dev/null
+++ b/tests/cases/user/jsonschema/index.ts
@@ -0,0 +1 @@
+import jsonschema = require("jsonschema");
diff --git a/tests/cases/user/jsonschema/package.json b/tests/cases/user/jsonschema/package.json
new file mode 100644
index 00000000000..daf42c5c0c7
--- /dev/null
+++ b/tests/cases/user/jsonschema/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "jsonschema-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "jsonschema": "latest"
+  }
+}
diff --git a/tests/cases/user/jsonschema/tsconfig.json b/tests/cases/user/jsonschema/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/jsonschema/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/keycode/index.ts b/tests/cases/user/keycode/index.ts
new file mode 100644
index 00000000000..cfa11252ecb
--- /dev/null
+++ b/tests/cases/user/keycode/index.ts
@@ -0,0 +1 @@
+import keycode = require("keycode");
diff --git a/tests/cases/user/keycode/package.json b/tests/cases/user/keycode/package.json
new file mode 100644
index 00000000000..73280239eb0
--- /dev/null
+++ b/tests/cases/user/keycode/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "keycode-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@types/node": "^8.0.47",
+    "keycode": "latest"
+  }
+}
diff --git a/tests/cases/user/keycode/tsconfig.json b/tests/cases/user/keycode/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/keycode/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/leveldown/index.ts b/tests/cases/user/leveldown/index.ts
new file mode 100644
index 00000000000..c595cfc3198
--- /dev/null
+++ b/tests/cases/user/leveldown/index.ts
@@ -0,0 +1 @@
+import leveldown = require("leveldown");
diff --git a/tests/cases/user/leveldown/package.json b/tests/cases/user/leveldown/package.json
new file mode 100644
index 00000000000..4ee61ed4ba4
--- /dev/null
+++ b/tests/cases/user/leveldown/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "leveldown-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@types/node": "^8.0.47",
+    "leveldown": "latest"
+  }
+}
diff --git a/tests/cases/user/leveldown/tsconfig.json b/tests/cases/user/leveldown/tsconfig.json
new file mode 100644
index 00000000000..a8a84f5c5fe
--- /dev/null
+++ b/tests/cases/user/leveldown/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": ["node"]
+    }
+}
diff --git a/tests/cases/user/localforage/index.ts b/tests/cases/user/localforage/index.ts
new file mode 100644
index 00000000000..dad26db93e3
--- /dev/null
+++ b/tests/cases/user/localforage/index.ts
@@ -0,0 +1 @@
+import localforage = require("localforage");
diff --git a/tests/cases/user/localforage/package.json b/tests/cases/user/localforage/package.json
new file mode 100644
index 00000000000..f02b0e02fb2
--- /dev/null
+++ b/tests/cases/user/localforage/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "localforage-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "localforage": "latest"
+  }
+}
diff --git a/tests/cases/user/localforage/tsconfig.json b/tests/cases/user/localforage/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/localforage/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/log4js/index.ts b/tests/cases/user/log4js/index.ts
new file mode 100644
index 00000000000..dbafe63e9dd
--- /dev/null
+++ b/tests/cases/user/log4js/index.ts
@@ -0,0 +1 @@
+import log4js = require("log4js");
diff --git a/tests/cases/user/log4js/package.json b/tests/cases/user/log4js/package.json
new file mode 100644
index 00000000000..1c5161081a7
--- /dev/null
+++ b/tests/cases/user/log4js/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "log4js-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "log4js": "latest"
+  }
+}
diff --git a/tests/cases/user/log4js/tsconfig.json b/tests/cases/user/log4js/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/log4js/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/mobx/index.ts b/tests/cases/user/mobx/index.ts
new file mode 100644
index 00000000000..b1cdddab88e
--- /dev/null
+++ b/tests/cases/user/mobx/index.ts
@@ -0,0 +1 @@
+import mobx = require("mobx");
diff --git a/tests/cases/user/mobx/package.json b/tests/cases/user/mobx/package.json
new file mode 100644
index 00000000000..99806321aa5
--- /dev/null
+++ b/tests/cases/user/mobx/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "mobx-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "mobx": "latest"
+  }
+}
diff --git a/tests/cases/user/mobx/tsconfig.json b/tests/cases/user/mobx/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/mobx/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/moment/index.ts b/tests/cases/user/moment/index.ts
new file mode 100644
index 00000000000..7ea0c0f0abc
--- /dev/null
+++ b/tests/cases/user/moment/index.ts
@@ -0,0 +1 @@
+import moment = require("moment");
diff --git a/tests/cases/user/moment/package.json b/tests/cases/user/moment/package.json
new file mode 100644
index 00000000000..fddf99c1c11
--- /dev/null
+++ b/tests/cases/user/moment/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "moment-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "moment": "latest"
+  }
+}
diff --git a/tests/cases/user/moment/tsconfig.json b/tests/cases/user/moment/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/moment/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/mqtt/index.ts b/tests/cases/user/mqtt/index.ts
new file mode 100644
index 00000000000..322527ef757
--- /dev/null
+++ b/tests/cases/user/mqtt/index.ts
@@ -0,0 +1 @@
+import mqtt = require("mqtt");
diff --git a/tests/cases/user/mqtt/package.json b/tests/cases/user/mqtt/package.json
new file mode 100644
index 00000000000..072c255d571
--- /dev/null
+++ b/tests/cases/user/mqtt/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "mqtt-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "mqtt": "latest"
+  }
+}
diff --git a/tests/cases/user/mqtt/tsconfig.json b/tests/cases/user/mqtt/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/mqtt/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/parse5/index.ts b/tests/cases/user/parse5/index.ts
new file mode 100644
index 00000000000..c640ea4f9cb
--- /dev/null
+++ b/tests/cases/user/parse5/index.ts
@@ -0,0 +1 @@
+import parse5 = require("parse5");
diff --git a/tests/cases/user/parse5/package.json b/tests/cases/user/parse5/package.json
new file mode 100644
index 00000000000..4b0aa84c0f3
--- /dev/null
+++ b/tests/cases/user/parse5/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "parse5-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "parse5": "latest"
+  }
+}
diff --git a/tests/cases/user/parse5/tsconfig.json b/tests/cases/user/parse5/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/parse5/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/portfinder/index.ts b/tests/cases/user/portfinder/index.ts
new file mode 100644
index 00000000000..9fafbff4adb
--- /dev/null
+++ b/tests/cases/user/portfinder/index.ts
@@ -0,0 +1 @@
+import portfinder = require("portfinder");
diff --git a/tests/cases/user/portfinder/package.json b/tests/cases/user/portfinder/package.json
new file mode 100644
index 00000000000..e7431dce9a2
--- /dev/null
+++ b/tests/cases/user/portfinder/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "portfinder-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "portfinder": "latest"
+  }
+}
diff --git a/tests/cases/user/portfinder/tsconfig.json b/tests/cases/user/portfinder/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/portfinder/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/postcss/index.ts b/tests/cases/user/postcss/index.ts
new file mode 100644
index 00000000000..e1480858fcd
--- /dev/null
+++ b/tests/cases/user/postcss/index.ts
@@ -0,0 +1 @@
+import postcss = require("postcss");
diff --git a/tests/cases/user/postcss/package.json b/tests/cases/user/postcss/package.json
new file mode 100644
index 00000000000..3c87e7357cd
--- /dev/null
+++ b/tests/cases/user/postcss/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "postcss-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "postcss": "latest"
+  }
+}
diff --git a/tests/cases/user/postcss/tsconfig.json b/tests/cases/user/postcss/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/postcss/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/protobufjs/index.ts b/tests/cases/user/protobufjs/index.ts
new file mode 100644
index 00000000000..cbbc52231d7
--- /dev/null
+++ b/tests/cases/user/protobufjs/index.ts
@@ -0,0 +1 @@
+import protobufjs = require("protobufjs");
diff --git a/tests/cases/user/protobufjs/package.json b/tests/cases/user/protobufjs/package.json
new file mode 100644
index 00000000000..20201e3728e
--- /dev/null
+++ b/tests/cases/user/protobufjs/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "protobufjs-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "protobufjs": "latest"
+  }
+}
diff --git a/tests/cases/user/protobufjs/tsconfig.json b/tests/cases/user/protobufjs/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/protobufjs/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/redux/index.ts b/tests/cases/user/redux/index.ts
new file mode 100644
index 00000000000..0475efa0567
--- /dev/null
+++ b/tests/cases/user/redux/index.ts
@@ -0,0 +1 @@
+import redux = require("redux");
diff --git a/tests/cases/user/redux/package.json b/tests/cases/user/redux/package.json
new file mode 100644
index 00000000000..c31108bcd95
--- /dev/null
+++ b/tests/cases/user/redux/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "redux-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "redux": "latest"
+  }
+}
diff --git a/tests/cases/user/redux/tsconfig.json b/tests/cases/user/redux/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/redux/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/reselect/index.ts b/tests/cases/user/reselect/index.ts
new file mode 100644
index 00000000000..ee93d241169
--- /dev/null
+++ b/tests/cases/user/reselect/index.ts
@@ -0,0 +1 @@
+import reselect = require("reselect");
diff --git a/tests/cases/user/reselect/package.json b/tests/cases/user/reselect/package.json
new file mode 100644
index 00000000000..fc335b32cc4
--- /dev/null
+++ b/tests/cases/user/reselect/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "reselect-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "reselect": "latest"
+  }
+}
diff --git a/tests/cases/user/reselect/tsconfig.json b/tests/cases/user/reselect/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/reselect/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/rxjs/index.ts b/tests/cases/user/rxjs/index.ts
new file mode 100644
index 00000000000..41418158bc5
--- /dev/null
+++ b/tests/cases/user/rxjs/index.ts
@@ -0,0 +1 @@
+import rxjs = require("rxjs");
diff --git a/tests/cases/user/rxjs/package.json b/tests/cases/user/rxjs/package.json
new file mode 100644
index 00000000000..1d006ed3c42
--- /dev/null
+++ b/tests/cases/user/rxjs/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "rxjs-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "rxjs": "latest"
+  }
+}
diff --git a/tests/cases/user/rxjs/tsconfig.json b/tests/cases/user/rxjs/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/rxjs/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/should/index.ts b/tests/cases/user/should/index.ts
new file mode 100644
index 00000000000..66e1a7aadfc
--- /dev/null
+++ b/tests/cases/user/should/index.ts
@@ -0,0 +1 @@
+import should = require("should");
diff --git a/tests/cases/user/should/package.json b/tests/cases/user/should/package.json
new file mode 100644
index 00000000000..8674a9f4f38
--- /dev/null
+++ b/tests/cases/user/should/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "should-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "should": "latest"
+  }
+}
diff --git a/tests/cases/user/should/tsconfig.json b/tests/cases/user/should/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/should/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/sift/index.ts b/tests/cases/user/sift/index.ts
new file mode 100644
index 00000000000..383f18d1b7d
--- /dev/null
+++ b/tests/cases/user/sift/index.ts
@@ -0,0 +1 @@
+import sift = require("sift");
diff --git a/tests/cases/user/sift/package.json b/tests/cases/user/sift/package.json
new file mode 100644
index 00000000000..344b2d73d11
--- /dev/null
+++ b/tests/cases/user/sift/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "sift-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "sift": "latest"
+  }
+}
diff --git a/tests/cases/user/sift/tsconfig.json b/tests/cases/user/sift/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/sift/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/soap/index.ts b/tests/cases/user/soap/index.ts
new file mode 100644
index 00000000000..d056570add2
--- /dev/null
+++ b/tests/cases/user/soap/index.ts
@@ -0,0 +1 @@
+import soap = require("soap");
diff --git a/tests/cases/user/soap/package.json b/tests/cases/user/soap/package.json
new file mode 100644
index 00000000000..5882bdeea5c
--- /dev/null
+++ b/tests/cases/user/soap/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "soap-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@types/bluebird": "^3.5.17",
+    "soap": "latest"
+  }
+}
diff --git a/tests/cases/user/soap/tsconfig.json b/tests/cases/user/soap/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/soap/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/sugar/index.ts b/tests/cases/user/sugar/index.ts
new file mode 100644
index 00000000000..2f959bdf704
--- /dev/null
+++ b/tests/cases/user/sugar/index.ts
@@ -0,0 +1 @@
+import sugar = require("sugar");
diff --git a/tests/cases/user/sugar/package.json b/tests/cases/user/sugar/package.json
new file mode 100644
index 00000000000..c1708049b62
--- /dev/null
+++ b/tests/cases/user/sugar/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "sugar-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "sugar": "latest"
+  }
+}
diff --git a/tests/cases/user/sugar/tsconfig.json b/tests/cases/user/sugar/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/sugar/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/tslint/index.ts b/tests/cases/user/tslint/index.ts
new file mode 100644
index 00000000000..249b3a054f6
--- /dev/null
+++ b/tests/cases/user/tslint/index.ts
@@ -0,0 +1 @@
+import tslint = require("tslint");
\ No newline at end of file
diff --git a/tests/cases/user/tslint/package.json b/tests/cases/user/tslint/package.json
new file mode 100644
index 00000000000..41a315e5110
--- /dev/null
+++ b/tests/cases/user/tslint/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "tslint-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "tslint": "latest",
+    "typescript": "latest"
+  },
+  "devDependencies": {
+    "@types/babel-code-frame": "latest",
+    "@types/chai": "latest",
+    "@types/chalk": "latest",
+    "@types/commander": "latest",
+    "@types/diff": "latest",
+    "@types/glob": "latest",
+    "@types/js-yaml": "latest",
+    "@types/minimatch": "latest",
+    "@types/mocha": "latest",
+    "@types/node": "latest",
+    "@types/resolve": "latest",
+    "@types/rimraf": "latest",
+    "@types/semver": "latest"
+  }
+}
diff --git a/tests/cases/user/tslint/tsconfig.json b/tests/cases/user/tslint/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/tslint/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/vue/index.ts b/tests/cases/user/vue/index.ts
new file mode 100644
index 00000000000..385522edcd9
--- /dev/null
+++ b/tests/cases/user/vue/index.ts
@@ -0,0 +1 @@
+import vue = require("vue");
diff --git a/tests/cases/user/vue/package.json b/tests/cases/user/vue/package.json
new file mode 100644
index 00000000000..69df82e9e0a
--- /dev/null
+++ b/tests/cases/user/vue/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "vue-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "vue": "latest"
+  }
+}
diff --git a/tests/cases/user/vue/tsconfig.json b/tests/cases/user/vue/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/vue/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/vuex/index.ts b/tests/cases/user/vuex/index.ts
new file mode 100644
index 00000000000..26e6c2efe19
--- /dev/null
+++ b/tests/cases/user/vuex/index.ts
@@ -0,0 +1 @@
+import vuex = require("vuex");
diff --git a/tests/cases/user/vuex/package.json b/tests/cases/user/vuex/package.json
new file mode 100644
index 00000000000..83d6c53c152
--- /dev/null
+++ b/tests/cases/user/vuex/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "vuex-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "vue": "^2.5.2",
+    "vuex": "latest"
+  }
+}
diff --git a/tests/cases/user/vuex/tsconfig.json b/tests/cases/user/vuex/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/vuex/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/xlsx/index.ts b/tests/cases/user/xlsx/index.ts
new file mode 100644
index 00000000000..bf5e78c75a7
--- /dev/null
+++ b/tests/cases/user/xlsx/index.ts
@@ -0,0 +1 @@
+import xlsx = require("xlsx");
diff --git a/tests/cases/user/xlsx/package.json b/tests/cases/user/xlsx/package.json
new file mode 100644
index 00000000000..398ba78ff69
--- /dev/null
+++ b/tests/cases/user/xlsx/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "xlsx-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "xlsx": "latest"
+  }
+}
diff --git a/tests/cases/user/xlsx/tsconfig.json b/tests/cases/user/xlsx/tsconfig.json
new file mode 100644
index 00000000000..cd66d349e94
--- /dev/null
+++ b/tests/cases/user/xlsx/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/user/xpath/index.ts b/tests/cases/user/xpath/index.ts
new file mode 100644
index 00000000000..b747fe100fb
--- /dev/null
+++ b/tests/cases/user/xpath/index.ts
@@ -0,0 +1 @@
+import xpath = require("xpath");
diff --git a/tests/cases/user/xpath/package.json b/tests/cases/user/xpath/package.json
new file mode 100644
index 00000000000..c97f1c46656
--- /dev/null
+++ b/tests/cases/user/xpath/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "xpath-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "xpath": "latest"
+  }
+}
diff --git a/tests/cases/user/xpath/tsconfig.json b/tests/cases/user/xpath/tsconfig.json
new file mode 100644
index 00000000000..aa10372d8d1
--- /dev/null
+++ b/tests/cases/user/xpath/tsconfig.json
@@ -0,0 +1,7 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015", "dom"],
+        "types": []
+    }
+}
diff --git a/tests/cases/user/zone.js/index.ts b/tests/cases/user/zone.js/index.ts
new file mode 100644
index 00000000000..533d8a07e1d
--- /dev/null
+++ b/tests/cases/user/zone.js/index.ts
@@ -0,0 +1 @@
+Zone.assertZonePatched
diff --git a/tests/cases/user/zone.js/package.json b/tests/cases/user/zone.js/package.json
new file mode 100644
index 00000000000..3828f62559e
--- /dev/null
+++ b/tests/cases/user/zone.js/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "zone.js-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "zone.js": "latest"
+  }
+}
diff --git a/tests/cases/user/zone.js/tsconfig.json b/tests/cases/user/zone.js/tsconfig.json
new file mode 100644
index 00000000000..3eff28851c6
--- /dev/null
+++ b/tests/cases/user/zone.js/tsconfig.json
@@ -0,0 +1,11 @@
+{
+    "compilerOptions": {
+        "strict": true,
+        "lib": ["es2015"],
+        "types": []
+    },
+    "files": [
+        "index.ts",
+        "node_modules/zone.js/dist/zone.js.d.ts"
+    ]
+}
diff --git a/tests/webTestServer.ts b/tests/webTestServer.ts
index 5a3b4cc5048..aff2ba0752a 100644
--- a/tests/webTestServer.ts
+++ b/tests/webTestServer.ts
@@ -61,7 +61,6 @@ function getRootLength(path: string): number {
     }
     if (path.charAt(1) === ":") {
         if (path.charAt(2) === directorySeparator) return 3;
-        return 2;
     }
     // Per RFC 1738 'file' URI schema has the shape file://<host>/<path>
     // if <host> is omitted then it is assumed that host value is 'localhost',
diff --git a/tslint.json b/tslint.json
index 06f76848fed..718c437b372 100644
--- a/tslint.json
+++ b/tslint.json
@@ -1,4 +1,5 @@
 {
+    "extends": "tslint:latest",
     "rulesDirectory": "built/local/tslint/rules",
     "rules": {
         "array-type": [true, "array"],
@@ -12,6 +13,7 @@
         "indent": [true,
             "spaces"
         ],
+        "interface-name": [true, "never-prefix"],
         "interface-over-type-literal": true,
         "jsdoc-format": true,
         "linebreak-style": [true, "CRLF"],
@@ -69,6 +71,49 @@
             "check-separator",
             "check-type"
         ],
-        "no-string-literal": true
+
+        // Config different from tslint:latest
+        "no-implicit-dependencies": [true, "dev"],
+        "object-literal-key-quotes": [true, "consistent-as-needed"],
+        "variable-name": [true, "ban-keywords", "check-format", "allow-leading-underscore"],
+
+        // TODO
+        "arrow-parens": false, // [true, "ban-single-arg-parens"]
+        "arrow-return-shorthand": false,
+        "ban-types": false,
+        "forin": false,
+        "member-access": false, // [true, "no-public"]
+        "no-conditional-assignment": false,
+        "no-console": false,
+        "no-debugger": false,
+        "no-empty-interface": false,
+        "no-eval": false,
+        "no-object-literal-type-assertion": false,
+        "no-shadowed-variable": false,
+        "no-submodule-imports": false,
+        "no-unnecessary-initializer": false,
+        "no-var-requires": false,
+        "ordered-imports": false,
+        "prefer-conditional-expression": false,
+        "radix": false,
+        "trailing-comma": false,
+
+        // These should be done automatically by a formatter. https://github.com/Microsoft/TypeScript/issues/18340
+        "align": false,
+        "eofline": false,
+        "max-line-length": false,
+        "no-consecutive-blank-lines": false,
+        "space-before-function-paren": false,
+
+        // Not doing
+        "ban-comma-operator": false,
+        "max-classes-per-file": false,
+        "member-ordering": false,
+        "no-angle-bracket-type-assertion": false,
+        "no-bitwise": false,
+        "no-namespace": false,
+        "no-reference": false,
+        "object-literal-sort-keys": false,
+        "one-variable-per-declaration": false
 	}
 }