From 668ac108902fc6f7fd3d55b0fd50aed70f64d998 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Fri, 3 Nov 2017 11:51:16 -0700
Subject: [PATCH 01/12] Test where script info path and program path differ
 because of current directory

---
 .../unittests/tsserverProjectSystem.ts        | 148 ++++++++++++------
 src/harness/virtualFileSystemWithWatch.ts     |  20 ++-
 2 files changed, 121 insertions(+), 47 deletions(-)

diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index be38176fb15..5df045335cb 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -437,6 +437,50 @@ 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",
@@ -2744,6 +2788,66 @@ namespace ts.projectSystem {
             const project = projectService.findProject(corruptedConfig.path);
             checkProjectRootFiles(project, [file1.path]);
         });
+
+        it("when opening new file that doesnt exist on disk yet", () => {
+            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: folderPath
+                }
+            });
+            checkNumberOfProjects(projectService, { inferredProjects: 1 });
+            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);
+            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);
+        });
     });
 
     describe("autoDiscovery", () => {
@@ -3446,50 +3550,6 @@ namespace ts.projectSystem {
             verifyNoDiagnostics(diags);
         });
 
-        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);
-        }
-
         it("npm install @types works", () => {
             const folderPath = "/a/b/projects/temp";
             const file1: FileOrFolder = {
diff --git a/src/harness/virtualFileSystemWithWatch.ts b/src/harness/virtualFileSystemWithWatch.ts
index fe40cb42844..6c3bd8a635a 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.
@@ -553,6 +563,10 @@ interface Array<T> {}`
             return this.timeoutCallbacks.register(callback, args);
         }
 
+        getNextTimeoutId() {
+            return this.timeoutCallbacks.getNextId();
+        }
+
         clearTimeout(timeoutId: any): void {
             this.timeoutCallbacks.unregister(timeoutId);
         }
@@ -567,9 +581,9 @@ 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) {

From 373510c4d9f1673fde5f3e17d9a4b63728acb4e7 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Fri, 3 Nov 2017 15:28:28 -0700
Subject: [PATCH 02/12] Handle the script infos that are opened with non rooted
 disk path Fixes #19588

---
 .../unittests/tsserverProjectSystem.ts        |  3 +-
 src/server/editorServices.ts                  | 46 ++++++++++++++-----
 src/server/project.ts                         | 10 ++--
 src/server/scriptInfo.ts                      |  4 +-
 .../reference/api/tsserverlibrary.d.ts        | 10 +++-
 5 files changed, 52 insertions(+), 21 deletions(-)

diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 5df045335cb..ae90ec7d741 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2837,8 +2837,9 @@ namespace ts.projectSystem {
 
             // Run the last one = get error request
             host.runQueuedTimeoutCallbacks(newTimeoutId);
-            host.checkTimeoutQueueLength(2);
 
+            assert.isFalse(hasError);
+            host.checkTimeoutQueueLength(2);
             checkErrorMessage(host, "syntaxDiag", { file: untitledFile, diagnostics: [] });
             host.clearOutput();
 
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 9ec190c152f..1730e545257 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -353,6 +353,10 @@ 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>();
@@ -930,12 +934,16 @@ 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[];
@@ -1535,7 +1543,7 @@ 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)) {
@@ -1689,9 +1697,9 @@ 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
             );
         }
@@ -1722,20 +1730,26 @@ 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)) {
@@ -1746,6 +1760,10 @@ 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
@@ -1762,8 +1780,12 @@ 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) {
@@ -1948,7 +1970,7 @@ 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 0444e9304b5..edb1d6730e9 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -285,7 +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) {
@@ -365,7 +365,7 @@ namespace ts.server {
 
         /*@internal*/
         toPath(fileName: string) {
-            return this.projectService.toPath(fileName);
+            return toPath(fileName, this.currentDirectory, this.projectService.toCanonicalFileName);
         }
 
         /*@internal*/
@@ -658,7 +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);
             }
@@ -855,7 +855,7 @@ 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)
@@ -901,7 +901,7 @@ 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);
             }
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/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index cffa1375608..64bbdd60c7c 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -7058,7 +7058,7 @@ 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;
@@ -7482,6 +7482,10 @@ 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;
         /**
@@ -7621,6 +7625,10 @@ 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;

From 163e40cde68d945dda726a93b748fa900e0b782e Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Mon, 6 Nov 2017 10:56:52 -0800
Subject: [PATCH 03/12] Add testcase for non existent file without absolute
 path when opened with/without projectRoot

---
 .../unittests/tsserverProjectSystem.ts        | 128 ++++++++++--------
 1 file changed, 74 insertions(+), 54 deletions(-)

diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index ae90ec7d741..a0a5995a1f0 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -2789,65 +2789,85 @@ namespace ts.projectSystem {
             checkProjectRootFiles(project, [file1.path]);
         });
 
-        it("when opening new file that doesnt exist on disk yet", () => {
-            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;
+        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
                     }
-                },
-                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: folderPath
+                });
+                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);
                 }
-            });
-            checkNumberOfProjects(projectService, { inferredProjects: 1 });
-            host.checkTimeoutQueueLength(2);
-
-            const newTimeoutId = host.getNextTimeoutId();
-            const expectedSequenceId = session.getNextSeq();
-            session.executeCommandSeq<protocol.GeterrRequest>({
-                command: server.CommandNames.Geterr,
-                arguments: {
-                    delay: 0,
-                    files: [untitledFile]
+                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);
             });
-            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("does not have projectRoot", () => {
+                verifyNonExistentFile(/*useProjectRoot*/ false);
+            });
         });
     });
 

From 4f48bf80fe2780741cbeb91dbaae2f2142a67995 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Mon, 6 Nov 2017 12:51:34 -0800
Subject: [PATCH 04/12] Revised emit for computed property names, including
 with decorators (#19430)

* Revised emit for computed property names

* Fix downlevel name generation scopes

* Accept slightly more conservative baseline

* First feedback pass

* Reduce number of nonrequired variable declarations and assignments

* Remove side-effect-free identifier references

* skip partially emitted expressions

* Comments, move starsOnNewLine to emitNode

* Put expressions on newlines when inlined in class expressions for consistency

* Update new ref

* Fix typo in comment
---
 src/compiler/binder.ts                        |   2 +
 src/compiler/emitter.ts                       |  64 +-
 src/compiler/factory.ts                       |  41 +-
 src/compiler/transformers/es2015.ts           |  17 +-
 src/compiler/transformers/generators.ts       |   5 +-
 src/compiler/transformers/ts.ts               |  96 ++-
 src/compiler/types.ts                         |   3 +-
 .../capturedParametersInInitializers2.js      |  15 +-
 .../reference/computedPropertyNames12_ES5.js  |   8 +-
 .../reference/computedPropertyNames12_ES6.js  |   8 +-
 .../reference/decoratorOnClassMethod13.js     |   9 +-
 .../reference/decoratorOnClassMethod4.js      |   5 +-
 .../reference/decoratorOnClassMethod5.js      |   5 +-
 .../reference/decoratorOnClassMethod6.js      |   5 +-
 .../reference/decoratorOnClassMethod7.js      |   5 +-
 .../decoratorsOnComputedProperties.errors.txt | 435 ++++++++++
 .../decoratorsOnComputedProperties.js         | 457 ++++++++++
 .../decoratorsOnComputedProperties.symbols    | 664 ++++++++++++++
 .../decoratorsOnComputedProperties.types      | 816 ++++++++++++++++++
 tests/baselines/reference/newTarget.es5.js    |   6 +-
 .../reference/parserComputedPropertyName10.js |   4 +-
 .../reference/parserComputedPropertyName25.js |   4 +-
 .../reference/parserComputedPropertyName27.js |   4 +-
 .../reference/parserComputedPropertyName28.js |   4 +-
 .../reference/parserComputedPropertyName29.js |   4 +-
 .../reference/parserComputedPropertyName33.js |   4 +-
 .../parserES5ComputedPropertyName10.js        |   4 +-
 tests/baselines/reference/symbolProperty7.js  |   5 +-
 .../decoratorsOnComputedProperties.ts         | 191 ++++
 29 files changed, 2777 insertions(+), 113 deletions(-)
 create mode 100644 tests/baselines/reference/decoratorsOnComputedProperties.errors.txt
 create mode 100644 tests/baselines/reference/decoratorsOnComputedProperties.js
 create mode 100644 tests/baselines/reference/decoratorsOnComputedProperties.symbols
 create mode 100644 tests/baselines/reference/decoratorsOnComputedProperties.types
 create mode 100644 tests/cases/compiler/decoratorsOnComputedProperties.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 72cff733b0c..cf8b3eefde8 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2963,6 +2963,7 @@ 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 +2994,7 @@ 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;
         }
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 74e5d4d5539..7a1d88d3bfd 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -1733,26 +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();
@@ -1871,11 +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();
@@ -1909,11 +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) {
@@ -1935,11 +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) {
@@ -2284,11 +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
@@ -2751,7 +2736,7 @@ namespace ts {
                 }
             }
             else {
-                return nextNode.startsOnNewLine;
+                return getStartsOnNewLine(nextNode);
             }
         }
 
@@ -2782,7 +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;
                 }
@@ -2799,7 +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;
             }
 
@@ -2858,7 +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;
         }
@@ -2866,7 +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();
         }
 
@@ -2877,8 +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
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 053672d19df..c9e0fec5927 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;
@@ -168,11 +165,14 @@ namespace ts {
     }
 
     /** Create a unique name generated for a node. */
-    export function getGeneratedNameForNode(node: Node): Identifier {
+    export function getGeneratedNameForNode(node: Node): Identifier;
+    /*@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;
     }
@@ -2683,6 +2683,24 @@ 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.
      */
@@ -2841,7 +2859,8 @@ 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.
@@ -2853,6 +2872,7 @@ 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;
     }
 
@@ -3014,7 +3034,7 @@ namespace ts {
 
             if (children.length > 1) {
                 for (const child of children) {
-                    child.startsOnNewLine = true;
+                    startOnNewLine(child);
                     argumentsList.push(child);
                 }
             }
@@ -3045,7 +3065,7 @@ namespace ts {
         if (children && children.length > 0) {
             if (children.length > 1) {
                 for (const child of children) {
-                    child.startsOnNewLine = true;
+                    startOnNewLine(child);
                     argumentsList.push(child);
                 }
             }
@@ -3620,8 +3640,8 @@ 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;
@@ -4250,8 +4270,7 @@ 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) {
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/ts.ts b/src/compiler/transformers/ts.ts
index 5339f2aaee5..39a4cc83bda 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -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;
 
         /**
@@ -395,9 +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.
@@ -584,6 +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);
 
@@ -598,6 +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:
@@ -856,6 +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));
@@ -871,7 +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) {
@@ -884,11 +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;
         }
 
@@ -1202,7 +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);
@@ -1218,7 +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);
 
@@ -2041,6 +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.
@@ -2050,7 +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;
             }
@@ -2062,6 +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
@@ -2071,15 +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;
@@ -2136,6 +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;
@@ -2156,7 +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.
          */
@@ -2200,7 +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.
          */
@@ -2231,7 +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/types.ts b/src/compiler/types.ts
index b4e84ae6a75..adab1f32492 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -520,7 +520,6 @@ 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)
@@ -630,6 +629,7 @@ 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)
@@ -4330,6 +4330,7 @@ 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/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/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/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/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/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/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/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/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/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

From 0593ba27d8ccc8fac551aade40985f086d264954 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Mon, 6 Nov 2017 12:52:33 -0800
Subject: [PATCH 05/12] Make getContextualTypeOfApparentType mapType over
 unions (#17668)

* Instantiate contextual types while in an inferrential context

* Limit scope of instantiation to only when likely needed

* Still get aparent type

* Expand test

* Fix nit

* Handle JSX and array

* Tests for the JSX and Array cases

* After much deliberation and inspection, much simpler fix

After much deliberation and inspection, much simpler fix

Undo

Redo
---
 src/compiler/checker.ts                       |   2 +-
 ...ntextualTypingOfOptionalMembers.errors.txt |  80 ++++++
 .../contextualTypingOfOptionalMembers.js      | 103 +++++++
 .../contextualTypingOfOptionalMembers.symbols | 235 ++++++++++++++++
 .../contextualTypingOfOptionalMembers.types   | 261 ++++++++++++++++++
 .../contextualTypingOfOptionalMembers.tsx     |  77 ++++++
 6 files changed, 757 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/contextualTypingOfOptionalMembers.errors.txt
 create mode 100644 tests/baselines/reference/contextualTypingOfOptionalMembers.js
 create mode 100644 tests/baselines/reference/contextualTypingOfOptionalMembers.symbols
 create mode 100644 tests/baselines/reference/contextualTypingOfOptionalMembers.types
 create mode 100644 tests/cases/compiler/contextualTypingOfOptionalMembers.tsx

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index eb5442a7996..39b0dc18569 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13691,7 +13691,7 @@ namespace ts {
         // be "pushed" onto a node using the contextualType property.
         function getApparentTypeOfContextualType(node: Expression): Type {
             const type = getContextualType(node);
-            return type && getApparentType(type);
+            return type && mapType(type, getApparentType);
         }
 
         /**
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/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

From 5b9905d5a41a55e49d2a8ca585dc936949ead71d Mon Sep 17 00:00:00 2001
From: Eugene Timokhov <timocov@gmail.com>
Date: Sat, 4 Nov 2017 11:08:00 +0300
Subject: [PATCH 06/12] Added empty constructors to TypedArrays from es2017
 (#19680)

---
 Gulpfile.ts                                   |  1 +
 Jakefile.js                                   |  3 +-
 src/compiler/commandLineParser.ts             |  1 +
 src/harness/unittests/commandLineParsing.ts   |  6 +--
 .../convertCompilerOptionsFromJson.ts         |  8 ++--
 src/lib/es2017.d.ts                           |  1 +
 src/lib/es2017.typedarrays.d.ts               | 35 ++++++++++++++
 tests/baselines/reference/useTypedArrays1.js  | 22 +++++++++
 .../reference/useTypedArrays1.symbols         | 37 +++++++++++++++
 .../baselines/reference/useTypedArrays1.types | 46 +++++++++++++++++++
 .../conformance/es2017/useTypedArrays1.ts     | 12 +++++
 11 files changed, 164 insertions(+), 8 deletions(-)
 create mode 100644 src/lib/es2017.typedarrays.d.ts
 create mode 100644 tests/baselines/reference/useTypedArrays1.js
 create mode 100644 tests/baselines/reference/useTypedArrays1.symbols
 create mode 100644 tests/baselines/reference/useTypedArrays1.types
 create mode 100644 tests/cases/conformance/es2017/useTypedArrays1.ts

diff --git a/Gulpfile.ts b/Gulpfile.ts
index fd353083433..a75882c5f46 100644
--- a/Gulpfile.ts
+++ b/Gulpfile.ts
@@ -138,6 +138,7 @@ const es2017LibrarySource = [
     "es2017.sharedmemory.d.ts",
     "es2017.string.d.ts",
     "es2017.intl.d.ts",
+    "es2017.typedarrays.d.ts",
 ];
 
 const es2017LibrarySourceMap = es2017LibrarySource.map(source =>
diff --git a/Jakefile.js b/Jakefile.js
index 7f0915ad7e9..89fcb6500dd 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -197,7 +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) {
diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index b7003fbffd9..7ba9bd80843 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -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",
                 }),
             },
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/convertCompilerOptionsFromJson.ts b/src/harness/unittests/convertCompilerOptionsFromJson.ts
index 09659762288..cbbe41ceadf 100644
--- a/src/harness/unittests/convertCompilerOptionsFromJson.ts
+++ b/src/harness/unittests/convertCompilerOptionsFromJson.ts
@@ -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
                     }]
@@ -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
                     }]
@@ -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
                     }]
@@ -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
                     }]
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/tests/baselines/reference/useTypedArrays1.js b/tests/baselines/reference/useTypedArrays1.js
new file mode 100644
index 00000000000..bbfcccec836
--- /dev/null
+++ b/tests/baselines/reference/useTypedArrays1.js
@@ -0,0 +1,22 @@
+//// [useTypedArrays1.ts]
+var int8Array = new Int8Array();
+var uint8Array = new Uint8Array();
+var uint8ClampedArray = new Uint8ClampedArray();
+var int16Array = new Int16Array();
+var uint16Array = new Uint16Array();
+var int32Array = new Int32Array();
+var uint32Array = new Uint32Array();
+var float32Array = new Float32Array();
+var float64Array = new Float64Array();
+
+
+//// [useTypedArrays1.js]
+var int8Array = new Int8Array();
+var uint8Array = new Uint8Array();
+var uint8ClampedArray = new Uint8ClampedArray();
+var int16Array = new Int16Array();
+var uint16Array = new Uint16Array();
+var int32Array = new Int32Array();
+var uint32Array = new Uint32Array();
+var float32Array = new Float32Array();
+var float64Array = new Float64Array();
diff --git a/tests/baselines/reference/useTypedArrays1.symbols b/tests/baselines/reference/useTypedArrays1.symbols
new file mode 100644
index 00000000000..ed41b0c24bd
--- /dev/null
+++ b/tests/baselines/reference/useTypedArrays1.symbols
@@ -0,0 +1,37 @@
+=== tests/cases/conformance/es2017/useTypedArrays1.ts ===
+var int8Array = new Int8Array();
+>int8Array : Symbol(int8Array, Decl(useTypedArrays1.ts, 0, 3))
+>Int8Array : Symbol(Int8Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var uint8Array = new Uint8Array();
+>uint8Array : Symbol(uint8Array, Decl(useTypedArrays1.ts, 1, 3))
+>Uint8Array : Symbol(Uint8Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var uint8ClampedArray = new Uint8ClampedArray();
+>uint8ClampedArray : Symbol(uint8ClampedArray, Decl(useTypedArrays1.ts, 2, 3))
+>Uint8ClampedArray : Symbol(Uint8ClampedArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var int16Array = new Int16Array();
+>int16Array : Symbol(int16Array, Decl(useTypedArrays1.ts, 3, 3))
+>Int16Array : Symbol(Int16Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var uint16Array = new Uint16Array();
+>uint16Array : Symbol(uint16Array, Decl(useTypedArrays1.ts, 4, 3))
+>Uint16Array : Symbol(Uint16Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var int32Array = new Int32Array();
+>int32Array : Symbol(int32Array, Decl(useTypedArrays1.ts, 5, 3))
+>Int32Array : Symbol(Int32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var uint32Array = new Uint32Array();
+>uint32Array : Symbol(uint32Array, Decl(useTypedArrays1.ts, 6, 3))
+>Uint32Array : Symbol(Uint32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var float32Array = new Float32Array();
+>float32Array : Symbol(float32Array, Decl(useTypedArrays1.ts, 7, 3))
+>Float32Array : Symbol(Float32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+var float64Array = new Float64Array();
+>float64Array : Symbol(float64Array, Decl(useTypedArrays1.ts, 8, 3))
+>Float64Array : Symbol(Float64Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
diff --git a/tests/baselines/reference/useTypedArrays1.types b/tests/baselines/reference/useTypedArrays1.types
new file mode 100644
index 00000000000..f3f27383a3e
--- /dev/null
+++ b/tests/baselines/reference/useTypedArrays1.types
@@ -0,0 +1,46 @@
+=== tests/cases/conformance/es2017/useTypedArrays1.ts ===
+var int8Array = new Int8Array();
+>int8Array : Int8Array
+>new Int8Array() : Int8Array
+>Int8Array : Int8ArrayConstructor
+
+var uint8Array = new Uint8Array();
+>uint8Array : Uint8Array
+>new Uint8Array() : Uint8Array
+>Uint8Array : Uint8ArrayConstructor
+
+var uint8ClampedArray = new Uint8ClampedArray();
+>uint8ClampedArray : Uint8ClampedArray
+>new Uint8ClampedArray() : Uint8ClampedArray
+>Uint8ClampedArray : Uint8ClampedArrayConstructor
+
+var int16Array = new Int16Array();
+>int16Array : Int16Array
+>new Int16Array() : Int16Array
+>Int16Array : Int16ArrayConstructor
+
+var uint16Array = new Uint16Array();
+>uint16Array : Uint16Array
+>new Uint16Array() : Uint16Array
+>Uint16Array : Uint16ArrayConstructor
+
+var int32Array = new Int32Array();
+>int32Array : Int32Array
+>new Int32Array() : Int32Array
+>Int32Array : Int32ArrayConstructor
+
+var uint32Array = new Uint32Array();
+>uint32Array : Uint32Array
+>new Uint32Array() : Uint32Array
+>Uint32Array : Uint32ArrayConstructor
+
+var float32Array = new Float32Array();
+>float32Array : Float32Array
+>new Float32Array() : Float32Array
+>Float32Array : Float32ArrayConstructor
+
+var float64Array = new Float64Array();
+>float64Array : Float64Array
+>new Float64Array() : Float64Array
+>Float64Array : Float64ArrayConstructor
+
diff --git a/tests/cases/conformance/es2017/useTypedArrays1.ts b/tests/cases/conformance/es2017/useTypedArrays1.ts
new file mode 100644
index 00000000000..e06bf91f317
--- /dev/null
+++ b/tests/cases/conformance/es2017/useTypedArrays1.ts
@@ -0,0 +1,12 @@
+// @target: es5
+// @lib: es5,es2017.typedarrays
+
+var int8Array = new Int8Array();
+var uint8Array = new Uint8Array();
+var uint8ClampedArray = new Uint8ClampedArray();
+var int16Array = new Int16Array();
+var uint16Array = new Uint16Array();
+var int32Array = new Int32Array();
+var uint32Array = new Uint32Array();
+var float32Array = new Float32Array();
+var float64Array = new Float64Array();

From 5c173f4436703aa6a75ac2fb93d3785905cb72fa Mon Sep 17 00:00:00 2001
From: Mohamed Hegazy <mhegazy@microsoft.com>
Date: Mon, 6 Nov 2017 12:51:52 -0800
Subject: [PATCH 07/12] Remove test

---
 tests/baselines/reference/useTypedArrays1.js  | 22 ---------
 .../reference/useTypedArrays1.symbols         | 37 ---------------
 .../baselines/reference/useTypedArrays1.types | 46 -------------------
 .../conformance/es2017/useTypedArrays1.ts     | 12 -----
 4 files changed, 117 deletions(-)
 delete mode 100644 tests/baselines/reference/useTypedArrays1.js
 delete mode 100644 tests/baselines/reference/useTypedArrays1.symbols
 delete mode 100644 tests/baselines/reference/useTypedArrays1.types
 delete mode 100644 tests/cases/conformance/es2017/useTypedArrays1.ts

diff --git a/tests/baselines/reference/useTypedArrays1.js b/tests/baselines/reference/useTypedArrays1.js
deleted file mode 100644
index bbfcccec836..00000000000
--- a/tests/baselines/reference/useTypedArrays1.js
+++ /dev/null
@@ -1,22 +0,0 @@
-//// [useTypedArrays1.ts]
-var int8Array = new Int8Array();
-var uint8Array = new Uint8Array();
-var uint8ClampedArray = new Uint8ClampedArray();
-var int16Array = new Int16Array();
-var uint16Array = new Uint16Array();
-var int32Array = new Int32Array();
-var uint32Array = new Uint32Array();
-var float32Array = new Float32Array();
-var float64Array = new Float64Array();
-
-
-//// [useTypedArrays1.js]
-var int8Array = new Int8Array();
-var uint8Array = new Uint8Array();
-var uint8ClampedArray = new Uint8ClampedArray();
-var int16Array = new Int16Array();
-var uint16Array = new Uint16Array();
-var int32Array = new Int32Array();
-var uint32Array = new Uint32Array();
-var float32Array = new Float32Array();
-var float64Array = new Float64Array();
diff --git a/tests/baselines/reference/useTypedArrays1.symbols b/tests/baselines/reference/useTypedArrays1.symbols
deleted file mode 100644
index ed41b0c24bd..00000000000
--- a/tests/baselines/reference/useTypedArrays1.symbols
+++ /dev/null
@@ -1,37 +0,0 @@
-=== tests/cases/conformance/es2017/useTypedArrays1.ts ===
-var int8Array = new Int8Array();
->int8Array : Symbol(int8Array, Decl(useTypedArrays1.ts, 0, 3))
->Int8Array : Symbol(Int8Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var uint8Array = new Uint8Array();
->uint8Array : Symbol(uint8Array, Decl(useTypedArrays1.ts, 1, 3))
->Uint8Array : Symbol(Uint8Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var uint8ClampedArray = new Uint8ClampedArray();
->uint8ClampedArray : Symbol(uint8ClampedArray, Decl(useTypedArrays1.ts, 2, 3))
->Uint8ClampedArray : Symbol(Uint8ClampedArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var int16Array = new Int16Array();
->int16Array : Symbol(int16Array, Decl(useTypedArrays1.ts, 3, 3))
->Int16Array : Symbol(Int16Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var uint16Array = new Uint16Array();
->uint16Array : Symbol(uint16Array, Decl(useTypedArrays1.ts, 4, 3))
->Uint16Array : Symbol(Uint16Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var int32Array = new Int32Array();
->int32Array : Symbol(int32Array, Decl(useTypedArrays1.ts, 5, 3))
->Int32Array : Symbol(Int32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var uint32Array = new Uint32Array();
->uint32Array : Symbol(uint32Array, Decl(useTypedArrays1.ts, 6, 3))
->Uint32Array : Symbol(Uint32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var float32Array = new Float32Array();
->float32Array : Symbol(float32Array, Decl(useTypedArrays1.ts, 7, 3))
->Float32Array : Symbol(Float32Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
-var float64Array = new Float64Array();
->float64Array : Symbol(float64Array, Decl(useTypedArrays1.ts, 8, 3))
->Float64Array : Symbol(Float64Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
-
diff --git a/tests/baselines/reference/useTypedArrays1.types b/tests/baselines/reference/useTypedArrays1.types
deleted file mode 100644
index f3f27383a3e..00000000000
--- a/tests/baselines/reference/useTypedArrays1.types
+++ /dev/null
@@ -1,46 +0,0 @@
-=== tests/cases/conformance/es2017/useTypedArrays1.ts ===
-var int8Array = new Int8Array();
->int8Array : Int8Array
->new Int8Array() : Int8Array
->Int8Array : Int8ArrayConstructor
-
-var uint8Array = new Uint8Array();
->uint8Array : Uint8Array
->new Uint8Array() : Uint8Array
->Uint8Array : Uint8ArrayConstructor
-
-var uint8ClampedArray = new Uint8ClampedArray();
->uint8ClampedArray : Uint8ClampedArray
->new Uint8ClampedArray() : Uint8ClampedArray
->Uint8ClampedArray : Uint8ClampedArrayConstructor
-
-var int16Array = new Int16Array();
->int16Array : Int16Array
->new Int16Array() : Int16Array
->Int16Array : Int16ArrayConstructor
-
-var uint16Array = new Uint16Array();
->uint16Array : Uint16Array
->new Uint16Array() : Uint16Array
->Uint16Array : Uint16ArrayConstructor
-
-var int32Array = new Int32Array();
->int32Array : Int32Array
->new Int32Array() : Int32Array
->Int32Array : Int32ArrayConstructor
-
-var uint32Array = new Uint32Array();
->uint32Array : Uint32Array
->new Uint32Array() : Uint32Array
->Uint32Array : Uint32ArrayConstructor
-
-var float32Array = new Float32Array();
->float32Array : Float32Array
->new Float32Array() : Float32Array
->Float32Array : Float32ArrayConstructor
-
-var float64Array = new Float64Array();
->float64Array : Float64Array
->new Float64Array() : Float64Array
->Float64Array : Float64ArrayConstructor
-
diff --git a/tests/cases/conformance/es2017/useTypedArrays1.ts b/tests/cases/conformance/es2017/useTypedArrays1.ts
deleted file mode 100644
index e06bf91f317..00000000000
--- a/tests/cases/conformance/es2017/useTypedArrays1.ts
+++ /dev/null
@@ -1,12 +0,0 @@
-// @target: es5
-// @lib: es5,es2017.typedarrays
-
-var int8Array = new Int8Array();
-var uint8Array = new Uint8Array();
-var uint8ClampedArray = new Uint8ClampedArray();
-var int16Array = new Int16Array();
-var uint16Array = new Uint16Array();
-var int32Array = new Int32Array();
-var uint32Array = new Uint32Array();
-var float32Array = new Float32Array();
-var float64Array = new Float64Array();

From ed38889ca66991d02728c3ed60ba3bf9d914d55e Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Mon, 6 Nov 2017 13:01:07 -0800
Subject: [PATCH 08/12] Enable 'no-unused-expression' tslint rule (#19734)

---
 src/compiler/checker.ts                       | 100 +++++++++---------
 src/harness/fourslash.ts                      |   8 +-
 src/harness/parallel/worker.ts                |   8 +-
 src/harness/unittests/languageService.ts      |   2 +-
 src/harness/unittests/session.ts              |   8 +-
 .../unittests/tsserverProjectSystem.ts        |  12 +--
 src/services/utilities.ts                     |   8 +-
 tslint.json                                   |   1 -
 8 files changed, 77 insertions(+), 70 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 39b0dc18569..649deef7e3a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1904,8 +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);
@@ -17016,8 +17017,7 @@ 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);
 
@@ -17064,7 +17064,7 @@ 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);
@@ -18739,9 +18739,7 @@ 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);
@@ -19131,14 +19129,13 @@ 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);
@@ -19154,7 +19151,7 @@ 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);
@@ -19251,7 +19248,7 @@ 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);
@@ -21013,8 +21010,7 @@ 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);
         }
 
@@ -21522,7 +21518,7 @@ namespace ts {
 
         function checkBreakOrContinueStatement(node: BreakOrContinueStatement) {
             // Grammar checking
-            checkGrammarStatementInAmbientContext(node) || checkGrammarBreakOrContinueStatement(node);
+            if (!checkGrammarStatementInAmbientContext(node)) checkGrammarBreakOrContinueStatement(node);
 
             // TODO: Check that target label is valid
         }
@@ -22203,7 +22199,7 @@ namespace ts {
 
         function checkInterfaceDeclaration(node: InterfaceDeclaration) {
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node) || checkGrammarInterfaceDeclaration(node);
+            if (!checkGrammarDecoratorsAndModifiers(node)) checkGrammarInterfaceDeclaration(node);
 
             checkTypeParameters(node.typeParameters);
             if (produceDiagnostics) {
@@ -22245,7 +22241,7 @@ 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);
@@ -22415,7 +22411,7 @@ namespace ts {
             }
 
             // Grammar checking
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
 
             checkTypeNameIsReserved(node.name, Diagnostics.Enum_name_cannot_be_0);
             checkCollisionWithCapturedThisVariable(node, node.name);
@@ -22518,7 +22514,7 @@ 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);
                     }
@@ -22741,7 +22737,7 @@ 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)) {
@@ -22768,7 +22764,7 @@ namespace ts {
                 return;
             }
 
-            checkGrammarDecorators(node) || checkGrammarModifiers(node);
+            checkGrammarDecoratorsAndModifiers(node);
             if (isInternalModuleImportEqualsDeclaration(node) || checkExternalImportOrExportDeclaration(node)) {
                 checkImportBinding(node);
                 if (hasModifier(node, ModifierFlags.Export)) {
@@ -22804,7 +22800,7 @@ namespace ts {
                 return;
             }
 
-            if (!checkGrammarDecorators(node) && !checkGrammarModifiers(node) && hasModifiers(node)) {
+            if (!checkGrammarDecoratorsAndModifiers(node) && hasModifiers(node)) {
                 grammarErrorOnFirstToken(node, Diagnostics.An_export_declaration_cannot_have_modifiers);
             }
 
@@ -22877,7 +22873,7 @@ 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) {
@@ -22922,29 +22918,31 @@ 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;
             }
         }
@@ -24577,12 +24575,16 @@ 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 {
@@ -24932,7 +24934,7 @@ 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);
         }
 
@@ -24988,7 +24990,7 @@ 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 {
@@ -25039,7 +25041,7 @@ 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) {
diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index dac8f7b8413..85011525d52 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -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) {
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/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/session.ts b/src/harness/unittests/session.ts
index e40e7d11b1a..871d4a37b9a 100644
--- a/src/harness/unittests/session.ts
+++ b/src/harness/unittests/session.ts
@@ -317,7 +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);
             });
         });
@@ -524,14 +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/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index c09a1bcb5da..55d767d24a7 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -1870,7 +1870,7 @@ 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 });
@@ -1929,7 +1929,7 @@ 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();
@@ -1948,7 +1948,7 @@ 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();
@@ -1967,7 +1967,7 @@ 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();
@@ -1986,7 +1986,7 @@ 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();
@@ -2005,7 +2005,7 @@ 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();
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 9397c40ff8a..36089f94f73 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -1398,7 +1398,9 @@ 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 +1417,9 @@ namespace ts {
                     }
                     return undefined;
                 });
-            lastChild && suppressTrailing(lastChild);
+            if (lastChild) {
+                suppressTrailing(lastChild);
+            }
         }
     }
 }
diff --git a/tslint.json b/tslint.json
index 9ad752e6094..497bd5e787a 100644
--- a/tslint.json
+++ b/tslint.json
@@ -93,7 +93,6 @@
         "no-object-literal-type-assertion": false,
         "no-shadowed-variable": false,
         "no-submodule-imports": false,
-        "no-unused-expression": false,
         "no-unnecessary-initializer": false,
         "no-var-requires": false,
         "object-literal-key-quotes": false,

From 28ed9b307b06bdf09dcad4cb10b31d82b19fc7c7 Mon Sep 17 00:00:00 2001
From: falsandtru <falsandtru@users.noreply.github.com>
Date: Tue, 7 Nov 2017 06:12:47 +0900
Subject: [PATCH 09/12] Update DOM iterable interfaces (#19752)

* Make HTMLCollections Iterable

* Sort definitions
---
 src/lib/dom.iterable.d.ts | 42 +++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

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

From a46d2705ef872a1c4f86a9dc5d7384b412e8ba5a Mon Sep 17 00:00:00 2001
From: Sean Barag <sjbarag@gmail.com>
Date: Mon, 6 Nov 2017 13:18:21 -0800
Subject: [PATCH 10/12] Use documentation comments from inherited properties
 when @inheritDoc is present (#18804)

* Use documentation comments from inherited properties when @inheritDoc is present

The JSDoc `@ineheritDoc` [tag](http://usejsdoc.org/tags-inheritdoc.html)
"indicates that a symbol should inherit its documentation from its
parent class".  In the case of a TypeScript file, this also includes
implemented interfaces and parent interfaces.

With this change, a class method or property (or an interface property)
with the `@inheritDoc` tag in its JSDoc comment will automatically use
the comments from its nearest ancestor that has no `@inheritDoc` tag.
To prevent breaking backwards compatibility,
`Symbol.getDocumentationComment` now accepts an optional `TypeChecker`
instance to support this feature.

fixes #8912

* Use ts.getJSDocTags as per @andy-ms 's recommendation

* Convert @inheritDoc tests to verify.quickInfoAt

* Concatenate inherited and local docs when @inheritDoc is present

* Make typeChecker param explicitly `TypeChecker | undefined`

* Re-accept baseline after switch to explicit `| undefined`

* Update APISample_jsodc.ts to match new getDocumentationComment signature

* Re-accept baselines after rebasing
---
 src/services/jsDoc.ts                         |  1 +
 src/services/services.ts                      | 96 ++++++++++++++++++-
 src/services/signatureHelp.ts                 |  6 +-
 src/services/symbolDisplay.ts                 |  6 +-
 src/services/types.ts                         |  4 +-
 tests/baselines/reference/APISample_jsdoc.js  |  4 +-
 .../reference/api/tsserverlibrary.d.ts        |  4 +-
 tests/baselines/reference/api/typescript.d.ts |  4 +-
 tests/cases/compiler/APISample_jsdoc.ts       |  2 +-
 tests/cases/fourslash/commentsInheritance.ts  | 10 +-
 tests/cases/fourslash/jsDocInheritDoc.ts      | 57 +++++++++++
 11 files changed, 170 insertions(+), 24 deletions(-)
 create mode 100644 tests/cases/fourslash/jsDocInheritDoc.ts

diff --git a/src/services/jsDoc.ts b/src/services/jsDoc.ts
index b8e94857aa7..79b08780226 100644
--- a/src/services/jsDoc.ts
+++ b/src/services/jsDoc.ts
@@ -20,6 +20,7 @@ namespace ts.JsDoc {
         "fileOverview",
         "function",
         "ignore",
+        "inheritDoc",
         "inner",
         "lends",
         "link",
diff --git a/src/services/services.ts b/src/services/services.ts
index 0dbdb57f309..237a9ce8d5b 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -346,9 +346,29 @@ 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;
@@ -477,7 +497,23 @@ 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;
@@ -492,6 +528,58 @@ 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;
@@ -1399,7 +1487,7 @@ 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
                             };
                         }
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 0465ec2aa70..e3ef4d3e495 100644
--- a/src/services/symbolDisplay.ts
+++ b/src/services/symbolDisplay.ts
@@ -438,7 +438,7 @@ 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`
@@ -455,7 +455,7 @@ namespace ts.SymbolDisplay {
                             continue;
                         }
 
-                        documentation = rhsSymbol.getDocumentationComment();
+                        documentation = rhsSymbol.getDocumentationComment(typeChecker);
                         tags = rhsSymbol.getJsDocTags();
                         if (documentation.length > 0) {
                             break;
@@ -524,7 +524,7 @@ 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/types.ts b/src/services/types.ts
index a3af3dbdf63..e93ae9686d7 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -32,7 +32,7 @@ namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
 
@@ -55,7 +55,7 @@ namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
 
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/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 663aa27a1b6..85895ffbce4 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -3813,7 +3813,7 @@ declare namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface Type {
@@ -3834,7 +3834,7 @@ declare namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface SourceFile {
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 62b7d4e885b..fd58e72181a 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -3813,7 +3813,7 @@ declare namespace ts {
         getEscapedName(): __String;
         getName(): string;
         getDeclarations(): Declaration[] | undefined;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface Type {
@@ -3834,7 +3834,7 @@ declare namespace ts {
         getTypeParameters(): TypeParameter[] | undefined;
         getParameters(): Symbol[];
         getReturnType(): Type;
-        getDocumentationComment(): SymbolDisplayPart[];
+        getDocumentationComment(typeChecker: TypeChecker | undefined): SymbolDisplayPart[];
         getJsDocTags(): JSDocTagInfo[];
     }
     interface SourceFile {
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/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/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

From fd64322a6372b17d442c95aadce95ff6115883fd Mon Sep 17 00:00:00 2001
From: csigs <csigs@outlook.com>
Date: Mon, 6 Nov 2017 23:10:47 +0000
Subject: [PATCH 11/12] LEGO: check in for master to temporary branch.

---
 .../diagnosticMessages.generated.json.lcl     | 36 +++++++++++++++++++
 .../diagnosticMessages.generated.json.lcl     | 36 +++++++++++++++++++
 2 files changed, 72 insertions(+)

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/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>

From d79c37cd191a5d10ad678f2a1379c6267e914bf2 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wwigham@gmail.com>
Date: Mon, 6 Nov 2017 16:09:35 -0800
Subject: [PATCH 12/12] Discriminate contextual types (#19733)

* Discriminate contextual types

* Invert conditional

* Update findMatchingDiscriminantType and baselines
---
 src/compiler/checker.ts                       | 59 ++++++++++++----
 .../contextuallyTypedByDiscriminableUnion.js  | 42 +++++++++++
 ...textuallyTypedByDiscriminableUnion.symbols | 60 ++++++++++++++++
 ...ontextuallyTypedByDiscriminableUnion.types | 70 +++++++++++++++++++
 .../excessPropertyCheckWithUnions.errors.txt  | 18 +++--
 .../excessPropertyCheckWithUnions.js          |  4 +-
 .../excessPropertyCheckWithUnions.symbols     |  2 +-
 .../excessPropertyCheckWithUnions.types       |  6 +-
 .../contextuallyTypedByDiscriminableUnion.ts  | 25 +++++++
 .../compiler/excessPropertyCheckWithUnions.ts |  2 +-
 10 files changed, 262 insertions(+), 26 deletions(-)
 create mode 100644 tests/baselines/reference/contextuallyTypedByDiscriminableUnion.js
 create mode 100644 tests/baselines/reference/contextuallyTypedByDiscriminableUnion.symbols
 create mode 100644 tests/baselines/reference/contextuallyTypedByDiscriminableUnion.types
 create mode 100644 tests/cases/compiler/contextuallyTypedByDiscriminableUnion.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 649deef7e3a..7d9a32a8f92 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -9269,20 +9269,24 @@ 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;
                             }
                         }
                     }
@@ -11396,14 +11400,15 @@ 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;
@@ -13691,8 +13696,32 @@ 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 && mapType(type, getApparentType);
+            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;
         }
 
         /**
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/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/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/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" }