Merge branch 'master' into literalEnumTypes

# Conflicts:
#	src/compiler/checker.ts
#	src/compiler/diagnosticMessages.json
#	src/compiler/types.ts
#	src/compiler/utilities.ts
#	src/services/completions.ts

src/compiler/binder.ts

@@ -149,7 +149,7 @@ namespace ts {
             inStrictMode = bindInStrictMode(file, opts);
             classifiableNames = createMap<string>();
             symbolCount = 0;
-            skipTransformFlagAggregation = isDeclarationFile(file);
+            skipTransformFlagAggregation = file.isDeclarationFile;
 
             Symbol = objectAllocator.getSymbolConstructor();
 
@@ -182,7 +182,7 @@ namespace ts {
         return bindSourceFile;
 
         function bindInStrictMode(file: SourceFile, opts: CompilerOptions): boolean {
-            if ((opts.alwaysStrict === undefined ? opts.strict : opts.alwaysStrict) && !isDeclarationFile(file)) {
+            if ((opts.alwaysStrict === undefined ? opts.strict : opts.alwaysStrict) && !file.isDeclarationFile) {
                 // bind in strict mode source files with alwaysStrict option
                 return true;
             }
@@ -221,18 +221,19 @@ namespace ts {
                     // other kinds of value declarations take precedence over modules
                     symbol.valueDeclaration = node;
                 }
-        }
+            }
         }
 
         // Should not be called on a declaration with a computed property name,
         // unless it is a well known Symbol.
         function getDeclarationName(node: Declaration): string {
-            if (node.name) {
+            const name = getNameOfDeclaration(node);
+            if (name) {
                 if (isAmbientModule(node)) {
-                    return isGlobalScopeAugmentation(<ModuleDeclaration>node) ? "__global" : `"${(<LiteralExpression>node.name).text}"`;
+                    return isGlobalScopeAugmentation(<ModuleDeclaration>node) ? "__global" : `"${(<LiteralExpression>name).text}"`;
                 }
-                if (node.name.kind === SyntaxKind.ComputedPropertyName) {
-                    const nameExpression = (<ComputedPropertyName>node.name).expression;
+                if (name.kind === SyntaxKind.ComputedPropertyName) {
+                    const nameExpression = (<ComputedPropertyName>name).expression;
                     // treat computed property names where expression is string/numeric literal as just string/numeric literal
                     if (isStringOrNumericLiteral(nameExpression)) {
                         return nameExpression.text;
@@ -241,7 +242,7 @@ namespace ts {
                     Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
                     return getPropertyNameForKnownSymbolName((<PropertyAccessExpression>nameExpression).name.text);
                 }
-                return (<Identifier | LiteralExpression>node.name).text;
+                return (<Identifier | LiteralExpression>name).text;
             }
             switch (node.kind) {
                 case SyntaxKind.Constructor:
@@ -303,7 +304,7 @@ namespace ts {
         }
 
         function getDisplayName(node: Declaration): string {
-            return node.name ? declarationNameToString(node.name) : getDeclarationName(node);
+            return (node as NamedDeclaration).name ? declarationNameToString((node as NamedDeclaration).name) : getDeclarationName(node);
         }
 
         /**
@@ -366,8 +367,8 @@ namespace ts {
                         symbolTable.set(name, symbol = createSymbol(SymbolFlags.None, name));
                     }
                     else {
-                        if (node.name) {
-                            node.name.parent = node;
+                        if ((node as NamedDeclaration).name) {
+                            (node as NamedDeclaration).name.parent = node;
                         }
 
                         // Report errors every position with duplicate declaration
@@ -389,16 +390,16 @@ namespace ts {
                                 // 1. multiple export default of class declaration or function declaration by checking NodeFlags.Default
                                 // 2. multiple export default of export assignment. This one doesn't have NodeFlags.Default on (as export default doesn't considered as modifiers)
                                 if (symbol.declarations && symbol.declarations.length &&
-                                    (isDefaultExport || (node.kind === SyntaxKind.ExportAssignment &&  !(<ExportAssignment>node).isExportEquals))) {
-                                        message = Diagnostics.A_module_cannot_have_multiple_default_exports;
-                                 }
+                                    (isDefaultExport || (node.kind === SyntaxKind.ExportAssignment && !(<ExportAssignment>node).isExportEquals))) {
+                                    message = Diagnostics.A_module_cannot_have_multiple_default_exports;
+                                }
                             }
                         }
 
                         forEach(symbol.declarations, declaration => {
-                            file.bindDiagnostics.push(createDiagnosticForNode(declaration.name || declaration, message, getDisplayName(declaration)));
+                            file.bindDiagnostics.push(createDiagnosticForNode(getNameOfDeclaration(declaration) || declaration, message, getDisplayName(declaration)));
                         });
-                        file.bindDiagnostics.push(createDiagnosticForNode(node.name || node, message, getDisplayName(node)));
+                        file.bindDiagnostics.push(createDiagnosticForNode(getNameOfDeclaration(node) || node, message, getDisplayName(node)));
 
                         symbol = createSymbol(SymbolFlags.None, name);
                     }
@@ -439,9 +440,9 @@ namespace ts {
                 //       and this case is specially handled. Module augmentations should only be merged with original module definition
                 //       and should never be merged directly with other augmentation, and the latter case would be possible if automatic merge is allowed.
                 const isJSDocTypedefInJSDocNamespace = node.kind === SyntaxKind.JSDocTypedefTag &&
-                    node.name &&
-                    node.name.kind === SyntaxKind.Identifier &&
-                    (<Identifier>node.name).isInJSDocNamespace;
+                    (node as JSDocTypedefTag).name &&
+                    (node as JSDocTypedefTag).name.kind === SyntaxKind.Identifier &&
+                    ((node as JSDocTypedefTag).name as Identifier).isInJSDocNamespace;
                 if ((!isAmbientModule(node) && (hasExportModifier || container.flags & NodeFlags.ExportContext)) || isJSDocTypedefInJSDocNamespace) {
                     const exportKind =
                         (symbolFlags & SymbolFlags.Value ? SymbolFlags.ExportValue : 0) |
@@ -1414,7 +1415,7 @@ namespace ts {
                     if (isObjectLiteralOrClassExpressionMethod(node)) {
                         return ContainerFlags.IsContainer | ContainerFlags.IsControlFlowContainer | ContainerFlags.HasLocals | ContainerFlags.IsFunctionLike | ContainerFlags.IsObjectLiteralOrClassExpressionMethod;
                     }
-                    // falls through
+                // falls through
                 case SyntaxKind.Constructor:
                 case SyntaxKind.FunctionDeclaration:
                 case SyntaxKind.MethodSignature:
@@ -1716,7 +1717,7 @@ namespace ts {
                         declareModuleMember(node, symbolFlags, symbolExcludes);
                         break;
                     }
-                    // falls through
+                // falls through
                 default:
                     if (!blockScopeContainer.locals) {
                         blockScopeContainer.locals = createMap<Symbol>();
@@ -2010,7 +2011,7 @@ namespace ts {
                         bindBlockScopedDeclaration(<Declaration>parentNode, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
                         break;
                     }
-                    // falls through
+                // falls through
                 case SyntaxKind.ThisKeyword:
                     if (currentFlow && (isExpression(node) || parent.kind === SyntaxKind.ShorthandPropertyAssignment)) {
                         node.flowNode = currentFlow;
@@ -2186,7 +2187,7 @@ namespace ts {
                     if (!isFunctionLike(node.parent)) {
                         return;
                     }
-                    // falls through
+                // falls through
                 case SyntaxKind.ModuleBlock:
                     return updateStrictModeStatementList((<Block | ModuleBlock>node).statements);
             }
@@ -2211,7 +2212,7 @@ namespace ts {
         }
 
         function bindSourceFileAsExternalModule() {
-            bindAnonymousDeclaration(file, SymbolFlags.ValueModule, `"${removeFileExtension(file.fileName) }"`);
+            bindAnonymousDeclaration(file, SymbolFlags.ValueModule, `"${removeFileExtension(file.fileName)}"`);
         }
 
         function bindExportAssignment(node: ExportAssignment | BinaryExpression) {
@@ -2504,7 +2505,7 @@ namespace ts {
         }
 
         function bindParameter(node: ParameterDeclaration) {
-            if (inStrictMode) {
+            if (inStrictMode && !isInAmbientContext(node)) {
                 // It is a SyntaxError if the identifier eval or arguments appears within a FormalParameterList of a
                 // strict mode FunctionLikeDeclaration or FunctionExpression(13.1)
                 checkStrictModeEvalOrArguments(node, node.name);
@@ -2526,7 +2527,7 @@ namespace ts {
         }
 
         function bindFunctionDeclaration(node: FunctionDeclaration) {
-            if (!isDeclarationFile(file) && !isInAmbientContext(node)) {
+            if (!file.isDeclarationFile && !isInAmbientContext(node)) {
                 if (isAsyncFunction(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }
@@ -2543,7 +2544,7 @@ namespace ts {
         }
 
         function bindFunctionExpression(node: FunctionExpression) {
-            if (!isDeclarationFile(file) && !isInAmbientContext(node)) {
+            if (!file.isDeclarationFile && !isInAmbientContext(node)) {
                 if (isAsyncFunction(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }
@@ -2557,7 +2558,7 @@ namespace ts {
         }
 
         function bindPropertyOrMethodOrAccessor(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags) {
-            if (!isDeclarationFile(file) && !isInAmbientContext(node)) {
+            if (!file.isDeclarationFile && !isInAmbientContext(node)) {
                 if (isAsyncFunction(node)) {
                     emitFlags |= NodeFlags.HasAsyncFunctions;
                 }

src/compiler/commandLineParser.ts

@@ -1088,58 +1088,38 @@ namespace ts {
      * @param host Instance of ParseConfigHost used to enumerate files in folder.
      * @param basePath A root directory to resolve relative path entries in the config
      *    file to. e.g. outDir
+     * @param resolutionStack Only present for backwards-compatibility. Should be empty.
      */
-    export function parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions: CompilerOptions = {}, configFileName?: string, resolutionStack: Path[] = [], extraFileExtensions: JsFileExtensionInfo[] = []): ParsedCommandLine {
+    export function parseJsonConfigFileContent(
+            json: any,
+            host: ParseConfigHost,
+            basePath: string,
+            existingOptions: CompilerOptions = {},
+            configFileName?: string,
+            resolutionStack: Path[] = [],
+            extraFileExtensions: JsFileExtensionInfo[] = [],
+            ): ParsedCommandLine {
         const errors: Diagnostic[] = [];
-        basePath = normalizeSlashes(basePath);
-        const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
-        const resolvedPath = toPath(configFileName || "", basePath, getCanonicalFileName);
-        if (resolutionStack.indexOf(resolvedPath) >= 0) {
-            return {
-                options: {},
-                fileNames: [],
-                typeAcquisition: {},
-                raw: json,
-                errors: [createCompilerDiagnostic(Diagnostics.Circularity_detected_while_resolving_configuration_Colon_0, [...resolutionStack, resolvedPath].join(" -> "))],
-                wildcardDirectories: {}
-            };
-        }
 
-        let options: CompilerOptions = convertCompilerOptionsFromJsonWorker(json["compilerOptions"], basePath, errors, configFileName);
+        let options = (() => {
+            const { include, exclude, files, options, compileOnSave } = parseConfig(json, host, basePath, configFileName, resolutionStack, errors);
+            if (include) { json.include = include; }
+            if (exclude) { json.exclude = exclude; }
+            if (files) { json.files = files; }
+            if (compileOnSave !== undefined) { json.compileOnSave = compileOnSave; }
+            return options;
+        })();
+
+        options = extend(existingOptions, options);
+        options.configFilePath = configFileName;
+
         // typingOptions has been deprecated and is only supported for backward compatibility purposes.
         // It should be removed in future releases - use typeAcquisition instead.
         const jsonOptions = json["typeAcquisition"] || json["typingOptions"];
         const typeAcquisition: TypeAcquisition = convertTypeAcquisitionFromJsonWorker(jsonOptions, basePath, errors, configFileName);
 
-        let baseCompileOnSave: boolean;
-        if (json["extends"]) {
-            let [include, exclude, files, baseOptions]: [string[], string[], string[], CompilerOptions] = [undefined, undefined, undefined, {}];
-            if (typeof json["extends"] === "string") {
-                [include, exclude, files, baseCompileOnSave, baseOptions] = (tryExtendsName(json["extends"]) || [include, exclude, files, baseCompileOnSave, baseOptions]);
-            }
-            else {
-                errors.push(createCompilerDiagnostic(Diagnostics.Compiler_option_0_requires_a_value_of_type_1, "extends", "string"));
-            }
-            if (include && !json["include"]) {
-                json["include"] = include;
-            }
-            if (exclude && !json["exclude"]) {
-                json["exclude"] = exclude;
-            }
-            if (files && !json["files"]) {
-                json["files"] = files;
-            }
-            options = assign({}, baseOptions, options);
-        }
-
-        options = extend(existingOptions, options);
-        options.configFilePath = configFileName;
-
-        const { fileNames, wildcardDirectories } = getFileNames(errors);
-        let compileOnSave = convertCompileOnSaveOptionFromJson(json, basePath, errors);
-        if (baseCompileOnSave && json[compileOnSaveCommandLineOption.name] === undefined) {
-            compileOnSave = baseCompileOnSave;
-        }
+        const { fileNames, wildcardDirectories } = getFileNames();
+        const compileOnSave = convertCompileOnSaveOptionFromJson(json, basePath, errors);
 
         return {
             options,
@@ -1151,40 +1131,7 @@ namespace ts {
             compileOnSave
         };
 
-        function tryExtendsName(extendedConfig: string): [string[], string[], string[], boolean, CompilerOptions] {
-            // If the path isn't a rooted or relative path, don't try to resolve it (we reserve the right to special case module-id like paths in the future)
-            if (!(isRootedDiskPath(extendedConfig) || startsWith(normalizeSlashes(extendedConfig), "./") || startsWith(normalizeSlashes(extendedConfig), "../"))) {
-                errors.push(createCompilerDiagnostic(Diagnostics.A_path_in_an_extends_option_must_be_relative_or_rooted_but_0_is_not, extendedConfig));
-                return;
-            }
-            let extendedConfigPath = toPath(extendedConfig, basePath, getCanonicalFileName);
-            if (!host.fileExists(extendedConfigPath) && !endsWith(extendedConfigPath, ".json")) {
-                extendedConfigPath = `${extendedConfigPath}.json` as Path;
-                if (!host.fileExists(extendedConfigPath)) {
-                    errors.push(createCompilerDiagnostic(Diagnostics.File_0_does_not_exist, extendedConfig));
-                    return;
-                }
-            }
-            const extendedResult = readConfigFile(extendedConfigPath, path => host.readFile(path));
-            if (extendedResult.error) {
-                errors.push(extendedResult.error);
-                return;
-            }
-            const extendedDirname = getDirectoryPath(extendedConfigPath);
-            const relativeDifference = convertToRelativePath(extendedDirname, basePath, getCanonicalFileName);
-            const updatePath: (path: string) => string = path => isRootedDiskPath(path) ? path : combinePaths(relativeDifference, path);
-            // Merge configs (copy the resolution stack so it is never reused between branches in potential diamond-problem scenarios)
-            const result = parseJsonConfigFileContent(extendedResult.config, host, extendedDirname, /*existingOptions*/ undefined, getBaseFileName(extendedConfigPath), resolutionStack.concat([resolvedPath]));
-            errors.push(...result.errors);
-            const [include, exclude, files] = map(["include", "exclude", "files"], key => {
-                if (!json[key] && extendedResult.config[key]) {
-                    return map(extendedResult.config[key], updatePath);
-                }
-            });
-            return [include, exclude, files, result.compileOnSave, result.options];
-        }
-
-        function getFileNames(errors: Diagnostic[]): ExpandResult {
+        function getFileNames(): ExpandResult {
             let fileNames: string[];
             if (hasProperty(json, "files")) {
                 if (isArray(json["files"])) {
@@ -1217,9 +1164,6 @@ namespace ts {
                     errors.push(createCompilerDiagnostic(Diagnostics.Compiler_option_0_requires_a_value_of_type_1, "exclude", "Array"));
                 }
             }
-            else if (hasProperty(json, "excludes")) {
-                errors.push(createCompilerDiagnostic(Diagnostics.Unknown_option_excludes_Did_you_mean_exclude));
-            }
             else {
                 // If no includes were specified, exclude common package folders and the outDir
                 excludeSpecs = includeSpecs ? [] : ["node_modules", "bower_components", "jspm_packages"];
@@ -1249,7 +1193,106 @@ namespace ts {
         }
     }
 
-    export function convertCompileOnSaveOptionFromJson(jsonOption: any, basePath: string, errors: Diagnostic[]): boolean | undefined {
+    interface ParsedTsconfig {
+        include: string[] | undefined;
+        exclude: string[] | undefined;
+        files: string[] | undefined;
+        options: CompilerOptions;
+        compileOnSave: boolean | undefined;
+    }
+
+    /**
+     * This *just* extracts options/include/exclude/files out of a config file.
+     * It does *not* resolve the included files.
+     */
+    function parseConfig(
+            json: any,
+            host: ParseConfigHost,
+            basePath: string,
+            configFileName: string,
+            resolutionStack: Path[],
+            errors: Diagnostic[],
+            ): ParsedTsconfig {
+
+        basePath = normalizeSlashes(basePath);
+        const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames);
+        const resolvedPath = toPath(configFileName || "", basePath, getCanonicalFileName);
+
+        if (resolutionStack.indexOf(resolvedPath) >= 0) {
+            errors.push(createCompilerDiagnostic(Diagnostics.Circularity_detected_while_resolving_configuration_Colon_0, [...resolutionStack, resolvedPath].join(" -> ")));
+            return { include: undefined, exclude: undefined, files: undefined, options: {}, compileOnSave: undefined };
+        }
+
+        if (hasProperty(json, "excludes")) {
+            errors.push(createCompilerDiagnostic(Diagnostics.Unknown_option_excludes_Did_you_mean_exclude));
+        }
+
+        let options: CompilerOptions = convertCompilerOptionsFromJsonWorker(json.compilerOptions, basePath, errors, configFileName);
+        let include: string[] | undefined = json.include, exclude: string[] | undefined = json.exclude,  files: string[] | undefined = json.files;
+        let compileOnSave: boolean | undefined = json.compileOnSave;
+
+        if (json.extends) {
+            // copy the resolution stack so it is never reused between branches in potential diamond-problem scenarios.
+            resolutionStack = resolutionStack.concat([resolvedPath]);
+            const base = getExtendedConfig(json.extends, host, basePath, getCanonicalFileName, resolutionStack, errors);
+            if (base) {
+                include = include || base.include;
+                exclude = exclude || base.exclude;
+                files = files || base.files;
+                if (compileOnSave === undefined) {
+                    compileOnSave = base.compileOnSave;
+                }
+                options = assign({}, base.options, options);
+            }
+        }
+
+        return { include, exclude, files, options, compileOnSave };
+    }
+
+    function getExtendedConfig(
+            extended: any, // Usually a string.
+            host: ts.ParseConfigHost,
+            basePath: string,
+            getCanonicalFileName: (fileName: string) => string,
+            resolutionStack: Path[],
+            errors: Diagnostic[],
+            ): ParsedTsconfig | undefined {
+        if (typeof extended !== "string") {
+            errors.push(createCompilerDiagnostic(Diagnostics.Compiler_option_0_requires_a_value_of_type_1, "extends", "string"));
+            return undefined;
+        }
+
+        extended = normalizeSlashes(extended);
+
+        // If the path isn't a rooted or relative path, don't try to resolve it (we reserve the right to special case module-id like paths in the future)
+        if (!(isRootedDiskPath(extended) || startsWith(extended, "./") || startsWith(extended, "../"))) {
+            errors.push(createCompilerDiagnostic(Diagnostics.A_path_in_an_extends_option_must_be_relative_or_rooted_but_0_is_not, extended));
+            return undefined;
+        }
+
+        let extendedConfigPath = toPath(extended, basePath, getCanonicalFileName);
+        if (!host.fileExists(extendedConfigPath) && !endsWith(extendedConfigPath, ".json")) {
+            extendedConfigPath = extendedConfigPath + ".json" as Path;
+            if (!host.fileExists(extendedConfigPath)) {
+                errors.push(createCompilerDiagnostic(Diagnostics.File_0_does_not_exist, extended));
+                return undefined;
+            }
+        }
+
+        const extendedResult = readConfigFile(extendedConfigPath, path => host.readFile(path));
+        if (extendedResult.error) {
+            errors.push(extendedResult.error);
+            return undefined;
+        }
+
+        const extendedDirname = getDirectoryPath(extendedConfigPath);
+        const relativeDifference = convertToRelativePath(extendedDirname, basePath, getCanonicalFileName);
+        const updatePath: (path: string) => string = path => isRootedDiskPath(path) ? path : combinePaths(relativeDifference, path);
+        const { include, exclude, files, options, compileOnSave } = parseConfig(extendedResult.config, host, extendedDirname, getBaseFileName(extendedConfigPath), resolutionStack, errors);
+        return { include: map(include, updatePath), exclude: map(exclude, updatePath), files: map(files, updatePath), compileOnSave, options };
+    }
+
+    export function convertCompileOnSaveOptionFromJson(jsonOption: any, basePath: string, errors: Diagnostic[]): boolean {
         if (!hasProperty(jsonOption, compileOnSaveCommandLineOption.name)) {
             return false;
         }

src/compiler/core.ts

@@ -3,7 +3,7 @@
 
 namespace ts {
     /** The version of the TypeScript compiler release */
-    export const version = "2.3.0";
+    export const version = "2.4.0";
 }
 
 /* @internal */
@@ -230,6 +230,8 @@ namespace ts {
      * If no such value is found, it applies the callback until the parent pointer is undefined or the callback returns "quit"
      * At that point findAncestor returns undefined.
      */
+    export function findAncestor<T extends Node>(node: Node, callback: (element: Node) => element is T): T | undefined;
+    export function findAncestor(node: Node, callback: (element: Node) => boolean | "quit"): Node | undefined;
     export function findAncestor(node: Node, callback: (element: Node) => boolean | "quit"): Node {
         while (node) {
             const result = callback(node);
@@ -251,6 +253,15 @@ namespace ts {
         }
     }
 
+    export function zipToMap<T>(keys: string[], values: T[]): Map<T> {
+        Debug.assert(keys.length === values.length);
+        const map = createMap<T>();
+        for (let i = 0; i < keys.length; ++i) {
+            map.set(keys[i], values[i]);
+        }
+        return map;
+    }
+
     /**
      * Iterates through `array` by index and performs the callback on each element of array until the callback
      * returns a falsey value, then returns false.
@@ -481,6 +492,35 @@ namespace ts {
         return result;
     }
 
+    /**
+     * Maps an array. If the mapped value is an array, it is spread into the result.
+     * Avoids allocation if all elements map to themselves.
+     *
+     * @param array The array to map.
+     * @param mapfn The callback used to map the result into one or more values.
+     */
+    export function sameFlatMap<T>(array: T[], mapfn: (x: T, i: number) => T | T[]): T[] {
+        let result: T[];
+        if (array) {
+            for (let i = 0; i < array.length; i++) {
+                const item = array[i];
+                const mapped = mapfn(item, i);
+                if (result || item !== mapped || isArray(mapped)) {
+                    if (!result) {
+                        result = array.slice(0, i);
+                    }
+                    if (isArray(mapped)) {
+                        addRange(result, mapped);
+                    }
+                    else {
+                        result.push(mapped);
+                    }
+                }
+            }
+        }
+        return result || array;
+    }
+
     /**
      * Computes the first matching span of elements and returns a tuple of the first span
      * and the remaining elements.

src/compiler/declarationEmitter.ts

@@ -67,7 +67,7 @@ namespace ts {
         let errorNameNode: DeclarationName;
         const emitJsDocComments = compilerOptions.removeComments ? noop : writeJsDocComments;
         const emit = compilerOptions.stripInternal ? stripInternal : emitNode;
-        let noDeclare: boolean;
+        let needsDeclare = true;
 
         let moduleElementDeclarationEmitInfo: ModuleElementDeclarationEmitInfo[] = [];
         let asynchronousSubModuleDeclarationEmitInfo: ModuleElementDeclarationEmitInfo[];
@@ -110,11 +110,11 @@ namespace ts {
 
             resultHasExternalModuleIndicator = false;
             if (!isBundledEmit || !isExternalModule(sourceFile)) {
-                noDeclare = false;
+                needsDeclare = true;
                 emitSourceFile(sourceFile);
             }
             else if (isExternalModule(sourceFile)) {
-                noDeclare = true;
+                needsDeclare = false;
                 write(`declare module "${getResolvedExternalModuleName(host, sourceFile)}" {`);
                 writeLine();
                 increaseIndent();
@@ -594,12 +594,11 @@ namespace ts {
             emitLines(node.statements);
         }
 
-        // Return a temp variable name to be used in `export default` statements.
+        // Return a temp variable name to be used in `export default`/`export class ... extends` statements.
         // The temp name will be of the form _default_counter.
         // Note that export default is only allowed at most once in a module, so we
         // do not need to keep track of created temp names.
-        function getExportDefaultTempVariableName(): string {
-            const baseName = "_default";
+        function getExportTempVariableName(baseName: string): string {
             if (!currentIdentifiers.has(baseName)) {
                 return baseName;
             }
@@ -613,24 +612,31 @@ namespace ts {
             }
         }
 
+        function emitTempVariableDeclaration(expr: Expression, baseName: string, diagnostic: SymbolAccessibilityDiagnostic, needsDeclare: boolean): string {
+            const tempVarName = getExportTempVariableName(baseName);
+            if (needsDeclare) {
+                write("declare ");
+            }
+            write("const ");
+            write(tempVarName);
+            write(": ");
+            writer.getSymbolAccessibilityDiagnostic = () => diagnostic;
+            resolver.writeTypeOfExpression(expr, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
+            write(";");
+            writeLine();
+            return tempVarName;
+        }
+
         function emitExportAssignment(node: ExportAssignment) {
             if (node.expression.kind === SyntaxKind.Identifier) {
                 write(node.isExportEquals ? "export = " : "export default ");
                 writeTextOfNode(currentText, node.expression);
             }
             else {
-                // Expression
-                const tempVarName = getExportDefaultTempVariableName();
-                if (!noDeclare) {
-                    write("declare ");
-                }
-                write("var ");
-                write(tempVarName);
-                write(": ");
-                writer.getSymbolAccessibilityDiagnostic = getDefaultExportAccessibilityDiagnostic;
-                resolver.writeTypeOfExpression(node.expression, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
-                write(";");
-                writeLine();
+                const tempVarName = emitTempVariableDeclaration(node.expression, "_default", {
+                    diagnosticMessage: Diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+                    errorNode: node
+                }, needsDeclare);
                 write(node.isExportEquals ? "export = " : "export default ");
                 write(tempVarName);
             }
@@ -644,13 +650,6 @@ namespace ts {
                 // write each of these declarations asynchronously
                 writeAsynchronousModuleElements(nodes);
             }
-
-            function getDefaultExportAccessibilityDiagnostic(): SymbolAccessibilityDiagnostic {
-                return {
-                    diagnosticMessage: Diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
-                    errorNode: node
-                };
-            }
         }
 
         function isModuleElementVisible(node: Declaration) {
@@ -729,7 +728,7 @@ namespace ts {
                 if (modifiers & ModifierFlags.Default) {
                     write("default ");
                 }
-                else if (node.kind !== SyntaxKind.InterfaceDeclaration && !noDeclare) {
+                else if (node.kind !== SyntaxKind.InterfaceDeclaration && needsDeclare) {
                     write("declare ");
                 }
             }
@@ -1097,7 +1096,7 @@ namespace ts {
             }
         }
 
-        function emitHeritageClause(className: Identifier, typeReferences: ExpressionWithTypeArguments[], isImplementsList: boolean) {
+        function emitHeritageClause(typeReferences: ExpressionWithTypeArguments[], isImplementsList: boolean) {
             if (typeReferences) {
                 write(isImplementsList ? " implements " : " extends ");
                 emitCommaList(typeReferences, emitTypeOfTypeReference);
@@ -1110,12 +1109,6 @@ namespace ts {
                 else if (!isImplementsList && node.expression.kind === SyntaxKind.NullKeyword) {
                     write("null");
                 }
-                else {
-                    writer.getSymbolAccessibilityDiagnostic = getHeritageClauseVisibilityError;
-                    errorNameNode = className;
-                    resolver.writeBaseConstructorTypeOfClass(<ClassLikeDeclaration>enclosingDeclaration, enclosingDeclaration, TypeFormatFlags.UseTypeOfFunction | TypeFormatFlags.UseTypeAliasValue, writer);
-                    errorNameNode = undefined;
-                }
 
                 function getHeritageClauseVisibilityError(): SymbolAccessibilityDiagnostic {
                     let diagnosticMessage: DiagnosticMessage;
@@ -1134,7 +1127,7 @@ namespace ts {
                     return {
                         diagnosticMessage,
                         errorNode: node,
-                        typeName: (<Declaration>node.parent.parent).name
+                        typeName: getNameOfDeclaration(node.parent.parent)
                     };
                 }
             }
@@ -1151,23 +1144,43 @@ namespace ts {
                 }
             }
 
+            const prevEnclosingDeclaration = enclosingDeclaration;
+            enclosingDeclaration = node;
+            const baseTypeNode = getClassExtendsHeritageClauseElement(node);
+            let tempVarName: string;
+            if (baseTypeNode && !isEntityNameExpression(baseTypeNode.expression)) {
+                tempVarName = baseTypeNode.expression.kind === SyntaxKind.NullKeyword ?
+                    "null" :
+                    emitTempVariableDeclaration(baseTypeNode.expression, `${node.name.text}_base`, {
+                        diagnosticMessage: Diagnostics.extends_clause_of_exported_class_0_has_or_is_using_private_name_1,
+                        errorNode: baseTypeNode,
+                        typeName: node.name
+                    }, !findAncestor(node, n => n.kind === SyntaxKind.ModuleDeclaration));
+            }
+
             emitJsDocComments(node);
             emitModuleElementDeclarationFlags(node);
             if (hasModifier(node, ModifierFlags.Abstract)) {
                 write("abstract ");
             }
-
             write("class ");
             writeTextOfNode(currentText, node.name);
-            const prevEnclosingDeclaration = enclosingDeclaration;
-            enclosingDeclaration = node;
             emitTypeParameters(node.typeParameters);
-            const baseTypeNode = getClassExtendsHeritageClauseElement(node);
             if (baseTypeNode) {
-                node.name;
-                emitHeritageClause(node.name, [baseTypeNode], /*isImplementsList*/ false);
+                if (!isEntityNameExpression(baseTypeNode.expression)) {
+                    write(" extends ");
+                    write(tempVarName);
+                    if (baseTypeNode.typeArguments) {
+                        write("<");
+                        emitCommaList(baseTypeNode.typeArguments, emitType);
+                        write(">");
+                    }
+                }
+                else  {
+                    emitHeritageClause([baseTypeNode], /*isImplementsList*/ false);
+                }
             }
-            emitHeritageClause(node.name, getClassImplementsHeritageClauseElements(node), /*isImplementsList*/ true);
+            emitHeritageClause(getClassImplementsHeritageClauseElements(node), /*isImplementsList*/ true);
             write(" {");
             writeLine();
             increaseIndent();
@@ -1189,7 +1202,7 @@ namespace ts {
             emitTypeParameters(node.typeParameters);
             const interfaceExtendsTypes = filter(getInterfaceBaseTypeNodes(node), base => isEntityNameExpression(base.expression));
             if (interfaceExtendsTypes && interfaceExtendsTypes.length) {
-                emitHeritageClause(node.name, interfaceExtendsTypes, /*isImplementsList*/ false);
+                emitHeritageClause(interfaceExtendsTypes, /*isImplementsList*/ false);
             }
             write(" {");
             writeLine();
@@ -1253,7 +1266,9 @@ namespace ts {
                         Diagnostics.Exported_variable_0_has_or_is_using_private_name_1;
                 }
                 // This check is to ensure we don't report error on constructor parameter property as that error would be reported during parameter emit
-                else if (node.kind === SyntaxKind.PropertyDeclaration || node.kind === SyntaxKind.PropertySignature) {
+                // The only exception here is if the constructor was marked as private. we are not emitting the constructor parameters at all.
+                else if (node.kind === SyntaxKind.PropertyDeclaration || node.kind === SyntaxKind.PropertySignature ||
+                    (node.kind === SyntaxKind.Parameter && hasModifier(node.parent, ModifierFlags.Private))) {
                     // TODO(jfreeman): Deal with computed properties in error reporting.
                     if (hasModifier(node, ModifierFlags.Static)) {
                         return symbolAccessibilityResult.errorModuleName ?
@@ -1262,7 +1277,7 @@ namespace ts {
                                 Diagnostics.Public_static_property_0_of_exported_class_has_or_is_using_name_1_from_private_module_2 :
                             Diagnostics.Public_static_property_0_of_exported_class_has_or_is_using_private_name_1;
                     }
-                    else if (node.parent.kind === SyntaxKind.ClassDeclaration) {
+                    else if (node.parent.kind === SyntaxKind.ClassDeclaration || node.kind === SyntaxKind.Parameter) {
                         return symbolAccessibilityResult.errorModuleName ?
                             symbolAccessibilityResult.accessibility === SymbolAccessibility.CannotBeNamed ?
                                 Diagnostics.Public_property_0_of_exported_class_has_or_is_using_name_1_from_external_module_2_but_cannot_be_named :
@@ -1488,6 +1503,11 @@ namespace ts {
                 write("[");
             }
             else {
+                if (node.kind === SyntaxKind.Constructor && hasModifier(node, ModifierFlags.Private)) {
+                    write("();");
+                    writeLine();
+                    return;
+                }
                 // Construct signature or constructor type write new Signature
                 if (node.kind === SyntaxKind.ConstructSignature || node.kind === SyntaxKind.ConstructorType) {
                     write("new ");
@@ -1820,7 +1840,7 @@ namespace ts {
         function writeReferencePath(referencedFile: SourceFile, addBundledFileReference: boolean, emitOnlyDtsFiles: boolean): boolean {
             let declFileName: string;
             let addedBundledEmitReference = false;
-            if (isDeclarationFile(referencedFile)) {
+            if (referencedFile.isDeclarationFile) {
                 // Declaration file, use declaration file name
                 declFileName = referencedFile.fileName;
             }

src/compiler/diagnosticMessages.json

@@ -635,6 +635,10 @@
         "category": "Error",
         "code": 1203
     },
+    "Cannot re-export a type when the '--isolatedModules' flag is provided.": {
+        "category": "Error",
+        "code": 1205
+    },
     "Decorators are not valid here.": {
         "category": "Error",
         "code": 1206
@@ -1843,10 +1847,18 @@
         "category": "Error",
         "code": 2550
     },
-    "Computed values are not permitted in an enum with string valued members.": {
+    "Property '{0}' does not exist on type '{1}'. Did you mean '{2}'?": {
         "category": "Error",
         "code": 2551
     },
+    "Cannot find name '{0}'. Did you mean '{1}'?": {
+        "category": "Error",
+        "code": 2552
+    },
+    "Computed values are not permitted in an enum with string valued members.": {
+        "category": "Error",
+        "code": 2553
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -3207,9 +3219,16 @@
     },
     "Scoped package detected, looking in '{0}'": {
         "category": "Message",
-        "code": "6182"
+        "code": 6182
+    },
+    "Reusing resolution of module '{0}' to file '{1}' from old program.": {
+        "category": "Message",
+        "code": 6183
+    },
+    "Reusing module resolutions originating in '{0}' since resolutions are unchanged from old program.": {
+        "category": "Message",
+        "code": 6184
     },
-
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
@@ -3536,7 +3555,10 @@
         "category": "Message",
         "code": 90021
     },
-
+    "Change spelling to '{0}'.": {
+        "category": "Message",
+        "code": 90022
+    },
 
     "Octal literal types must use ES2015 syntax. Use the syntax '{0}'.": {
         "category": "Error",

src/compiler/emitter.ts

@@ -153,7 +153,7 @@ namespace ts {
             for (let i = 0; i < numNodes; i++) {
                 const currentNode = bundle ? bundle.sourceFiles[i] : node;
                 const sourceFile = isSourceFile(currentNode) ? currentNode : currentSourceFile;
-                const shouldSkip = compilerOptions.noEmitHelpers || (sourceFile && getExternalHelpersModuleName(sourceFile) !== undefined);
+                const shouldSkip = compilerOptions.noEmitHelpers || getExternalHelpersModuleName(sourceFile) !== undefined;
                 const shouldBundle = isSourceFile(currentNode) && !isOwnFileEmit;
                 const helpers = getEmitHelpers(currentNode);
                 if (helpers) {
@@ -212,7 +212,7 @@ namespace ts {
             emitLeadingCommentsOfPosition,
         } = comments;
 
-        let currentSourceFile: SourceFile;
+        let currentSourceFile: SourceFile | undefined;
         let nodeIdToGeneratedName: string[]; // Map of generated names for specific nodes.
         let autoGeneratedIdToGeneratedName: string[]; // Map of generated names for temp and loop variables.
         let generatedNames: Map<string>; // Set of names generated by the NameGenerator.
@@ -264,7 +264,12 @@ namespace ts {
             return endPrint();
         }
 
-        function writeNode(hint: EmitHint, node: Node, sourceFile: SourceFile, output: EmitTextWriter) {
+        /**
+         * If `sourceFile` is `undefined`, `node` must be a synthesized `TypeNode`.
+         */
+        function writeNode(hint: EmitHint, node: TypeNode, sourceFile: undefined, output: EmitTextWriter): void;
+        function writeNode(hint: EmitHint, node: Node, sourceFile: SourceFile, output: EmitTextWriter): void;
+        function writeNode(hint: EmitHint, node: Node, sourceFile: SourceFile | undefined, output: EmitTextWriter) {
             const previousWriter = writer;
             setWriter(output);
             print(hint, node, sourceFile);
@@ -305,8 +310,10 @@ namespace ts {
             return text;
         }
 
-        function print(hint: EmitHint, node: Node, sourceFile: SourceFile) {
-            setSourceFile(sourceFile);
+        function print(hint: EmitHint, node: Node, sourceFile: SourceFile | undefined) {
+            if (sourceFile) {
+                setSourceFile(sourceFile);
+            }
             pipelineEmitWithNotification(hint, node);
         }
 
@@ -733,6 +740,9 @@ namespace ts {
                 // Transformation nodes
                 case SyntaxKind.PartiallyEmittedExpression:
                     return emitPartiallyEmittedExpression(<PartiallyEmittedExpression>node);
+
+                case SyntaxKind.CommaListExpression:
+                    return emitCommaList(<CommaListExpression>node);
             }
         }
 
@@ -778,6 +788,7 @@ namespace ts {
 
         function emitIdentifier(node: Identifier) {
             write(getTextOfNode(node, /*includeTrivia*/ false));
+            emitTypeArguments(node, node.typeArguments);
         }
 
         //
@@ -812,6 +823,7 @@ namespace ts {
         function emitTypeParameter(node: TypeParameterDeclaration) {
             emit(node.name);
             emitWithPrefix(" extends ", node.constraint);
+            emitWithPrefix(" = ", node.default);
         }
 
         function emitParameter(node: ParameterDeclaration) {
@@ -952,7 +964,10 @@ namespace ts {
 
         function emitTypeLiteral(node: TypeLiteralNode) {
             write("{");
-            emitList(node, node.members, ListFormat.TypeLiteralMembers);
+            // If the literal is empty, do not add spaces between braces.
+            if (node.members.length > 0) {
+                emitList(node, node.members, getEmitFlags(node) & EmitFlags.SingleLine ? ListFormat.SingleLineTypeLiteralMembers : ListFormat.MultiLineTypeLiteralMembers);
+            }
             write("}");
         }
 
@@ -999,9 +1014,15 @@ namespace ts {
         }
 
         function emitMappedType(node: MappedTypeNode) {
+            const emitFlags = getEmitFlags(node);
             write("{");
-            writeLine();
-            increaseIndent();
+            if (emitFlags & EmitFlags.SingleLine) {
+                write(" ");
+            }
+            else {
+                writeLine();
+                increaseIndent();
+            }
             writeIfPresent(node.readonlyToken, "readonly ");
             write("[");
             emit(node.typeParameter.name);
@@ -1012,8 +1033,13 @@ namespace ts {
             write(": ");
             emit(node.type);
             write(";");
-            writeLine();
-            decreaseIndent();
+            if (emitFlags & EmitFlags.SingleLine) {
+                write(" ");
+            }
+            else {
+                writeLine();
+                decreaseIndent();
+            }
             write("}");
         }
 
@@ -1032,7 +1058,7 @@ namespace ts {
             }
             else {
                 write("{");
-                emitList(node, elements, ListFormat.ObjectBindingPatternElements);
+                emitList(node, elements, getEmitFlags(node) & EmitFlags.SingleLine ? ListFormat.ObjectBindingPatternElements : ListFormat.ObjectBindingPatternElementsWithSpaceBetweenBraces);
                 write("}");
             }
         }
@@ -2101,6 +2127,10 @@ namespace ts {
             emitExpression(node.expression);
         }
 
+        function emitCommaList(node: CommaListExpression) {
+            emitExpressionList(node, node.elements, ListFormat.CommaListElements);
+        }
+
         /**
          * Emits any prologue directives at the start of a Statement list, returning the
          * number of prologue directives written to the output.
@@ -2630,7 +2660,9 @@ namespace ts {
             if (node.kind === SyntaxKind.StringLiteral && (<StringLiteral>node).textSourceNode) {
                 const textSourceNode = (<StringLiteral>node).textSourceNode;
                 if (isIdentifier(textSourceNode)) {
-                    return "\"" + escapeNonAsciiCharacters(escapeString(getTextOfNode(textSourceNode))) + "\"";
+                    return getEmitFlags(node) & EmitFlags.NoAsciiEscaping ?
+                        `"${escapeString(getTextOfNode(textSourceNode))}"` :
+                        `"${escapeNonAsciiString(getTextOfNode(textSourceNode))}"`;
                 }
                 else {
                     return getLiteralTextOfNode(textSourceNode);
@@ -2943,14 +2975,18 @@ namespace ts {
         // Precomputed Formats
         Modifiers = SingleLine | SpaceBetweenSiblings,
         HeritageClauses = SingleLine | SpaceBetweenSiblings,
-        TypeLiteralMembers = MultiLine | Indented,
+        SingleLineTypeLiteralMembers = SingleLine | SpaceBetweenBraces | SpaceBetweenSiblings | Indented,
+        MultiLineTypeLiteralMembers = MultiLine | Indented,
+
         TupleTypeElements = CommaDelimited | SpaceBetweenSiblings | SingleLine | Indented,
         UnionTypeConstituents = BarDelimited | SpaceBetweenSiblings | SingleLine,
         IntersectionTypeConstituents = AmpersandDelimited | SpaceBetweenSiblings | SingleLine,
-        ObjectBindingPatternElements = SingleLine | AllowTrailingComma | SpaceBetweenBraces | CommaDelimited | SpaceBetweenSiblings,
+        ObjectBindingPatternElements = SingleLine | CommaDelimited | SpaceBetweenSiblings,
+        ObjectBindingPatternElementsWithSpaceBetweenBraces = SingleLine | AllowTrailingComma | SpaceBetweenBraces | CommaDelimited | SpaceBetweenSiblings,
         ArrayBindingPatternElements = SingleLine | AllowTrailingComma | CommaDelimited | SpaceBetweenSiblings,
         ObjectLiteralExpressionProperties = PreserveLines | CommaDelimited | SpaceBetweenSiblings | SpaceBetweenBraces | Indented | Braces,
         ArrayLiteralExpressionElements = PreserveLines | CommaDelimited | SpaceBetweenSiblings | AllowTrailingComma | Indented | SquareBrackets,
+        CommaListElements = CommaDelimited | SpaceBetweenSiblings | SingleLine,
         CallExpressionArguments = CommaDelimited | SpaceBetweenSiblings | SingleLine | Parenthesis,
         NewExpressionArguments = CommaDelimited | SpaceBetweenSiblings | SingleLine | Parenthesis | OptionalIfUndefined,
         TemplateExpressionSpans = SingleLine | NoInterveningComments,

src/compiler/moduleNameResolver.ts

@@ -2,7 +2,6 @@
 /// <reference path="diagnosticInformationMap.generated.ts" />
 
 namespace ts {
-
     /* @internal */
     export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
     export function trace(host: ModuleResolutionHost): void {
@@ -15,6 +14,7 @@ namespace ts {
     }
 
     /** Array that is only intended to be pushed to, never read. */
+    /* @internal */
     export interface Push<T> {
         push(value: T): void;
     }
@@ -47,13 +47,11 @@ namespace ts {
         return resolved.path;
     }
 
-    /** Adds `isExernalLibraryImport` to a Resolved to get a ResolvedModule. */
-    function resolvedModuleFromResolved({ path, extension }: Resolved, isExternalLibraryImport: boolean): ResolvedModuleFull {
-        return { resolvedFileName: path, extension, isExternalLibraryImport };
-    }
-
     function createResolvedModuleWithFailedLookupLocations(resolved: Resolved | undefined, isExternalLibraryImport: boolean, failedLookupLocations: string[]): ResolvedModuleWithFailedLookupLocations {
-        return { resolvedModule: resolved && resolvedModuleFromResolved(resolved, isExternalLibraryImport), failedLookupLocations };
+        return {
+            resolvedModule: resolved && { resolvedFileName: resolved.path, extension: resolved.extension, isExternalLibraryImport },
+            failedLookupLocations
+        };
     }
 
     export function moduleHasNonRelativeName(moduleName: string): boolean {
@@ -442,6 +440,8 @@ namespace ts {
                 case ModuleResolutionKind.Classic:
                     result = classicNameResolver(moduleName, containingFile, compilerOptions, host, cache);
                     break;
+                default:
+                    Debug.fail(`Unexpected moduleResolution: ${moduleResolution}`);
             }
 
             if (perFolderCache) {
@@ -675,12 +675,25 @@ namespace ts {
     }
 
     export function nodeModuleNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache?: ModuleResolutionCache): ResolvedModuleWithFailedLookupLocations {
-        return nodeModuleNameResolverWorker(moduleName, containingFile, compilerOptions, host, cache, /*jsOnly*/ false);
+        return nodeModuleNameResolverWorker(moduleName, getDirectoryPath(containingFile), compilerOptions, host, cache, /*jsOnly*/ false);
     }
 
+    /**
+     * Expose resolution logic to allow us to use Node module resolution logic from arbitrary locations.
+     * No way to do this with `require()`: https://github.com/nodejs/node/issues/5963
+     * Throws an error if the module can't be resolved.
+     */
     /* @internal */
-    export function nodeModuleNameResolverWorker(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache?: ModuleResolutionCache, jsOnly = false): ResolvedModuleWithFailedLookupLocations {
-        const containingDirectory = getDirectoryPath(containingFile);
+    export function resolveJavaScriptModule(moduleName: string, initialDir: string, host: ModuleResolutionHost): string {
+        const { resolvedModule, failedLookupLocations } =
+            nodeModuleNameResolverWorker(moduleName, initialDir, { moduleResolution: ts.ModuleResolutionKind.NodeJs, allowJs: true }, host, /*cache*/ undefined, /*jsOnly*/ true);
+        if (!resolvedModule) {
+            throw new Error(`Could not resolve JS module ${moduleName} starting at ${initialDir}. Looked in: ${failedLookupLocations.join(", ")}`);
+        }
+        return resolvedModule.resolvedFileName;
+    }
+
+    function nodeModuleNameResolverWorker(moduleName: string, containingDirectory: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost, cache: ModuleResolutionCache | undefined, jsOnly: boolean): ResolvedModuleWithFailedLookupLocations {
         const traceEnabled = isTraceEnabled(compilerOptions, host);
 
         const failedLookupLocations: string[] = [];

src/compiler/parser.ts

@@ -23,19 +23,19 @@ namespace ts {
         }
     }
 
-    function visitNode<T>(cbNode: (node: Node) => T, node: Node): T {
+    function visitNode<T>(cbNode: (node: Node) => T, node: Node): T | undefined {
         if (node) {
             return cbNode(node);
         }
     }
 
-    function visitNodeArray<T>(cbNodes: (nodes: Node[]) => T, nodes: Node[]) {
+    function visitNodeArray<T>(cbNodes: (nodes: Node[]) => T, nodes: Node[]): T | undefined {
         if (nodes) {
             return cbNodes(nodes);
         }
     }
 
-    function visitEachNode<T>(cbNode: (node: Node) => T, nodes: Node[]) {
+    function visitEachNode<T>(cbNode: (node: Node) => T, nodes: Node[]): T | undefined {
         if (nodes) {
             for (const node of nodes) {
                 const result = cbNode(node);
@@ -50,7 +50,7 @@ namespace ts {
     // stored in properties. If a 'cbNodes' callback is specified, it is invoked for embedded arrays; otherwise,
     // embedded arrays are flattened and the 'cbNode' callback is invoked for each element. If a callback returns
     // a truthy value, iteration stops and that value is returned. Otherwise, undefined is returned.
-    export function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T {
+    export function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T | undefined {
         if (!node) {
             return;
         }
@@ -362,6 +362,8 @@ namespace ts {
                 return visitNode(cbNode, (<ExternalModuleReference>node).expression);
             case SyntaxKind.MissingDeclaration:
                 return visitNodes(cbNodes, node.decorators);
+            case SyntaxKind.CommaListExpression:
+                return visitNodes(cbNodes, (<CommaListExpression>node).elements);
 
             case SyntaxKind.JsxElement:
                 return visitNode(cbNode, (<JsxElement>node).openingElement) ||
@@ -6502,6 +6504,8 @@ namespace ts {
                             case "augments":
                                 tag = parseAugmentsTag(atToken, tagName);
                                 break;
+                            case "arg":
+                            case "argument":
                             case "param":
                                 tag = parseParamTag(atToken, tagName);
                                 break;

src/compiler/program.ts

@@ -241,6 +241,101 @@ namespace ts {
         return output;
     }
 
+    const redForegroundEscapeSequence = "\u001b[91m";
+    const yellowForegroundEscapeSequence = "\u001b[93m";
+    const blueForegroundEscapeSequence = "\u001b[93m";
+    const gutterStyleSequence = "\u001b[100;30m";
+    const gutterSeparator = " ";
+    const resetEscapeSequence = "\u001b[0m";
+    const ellipsis = "...";
+    function getCategoryFormat(category: DiagnosticCategory): string {
+        switch (category) {
+            case DiagnosticCategory.Warning: return yellowForegroundEscapeSequence;
+            case DiagnosticCategory.Error: return redForegroundEscapeSequence;
+            case DiagnosticCategory.Message: return blueForegroundEscapeSequence;
+        }
+    }
+
+    function formatAndReset(text: string, formatStyle: string) {
+        return formatStyle + text + resetEscapeSequence;
+    }
+
+    function padLeft(s: string, length: number) {
+        while (s.length < length) {
+            s = " " + s;
+        }
+        return s;
+    }
+
+    export function formatDiagnosticsWithColorAndContext(diagnostics: Diagnostic[], host: FormatDiagnosticsHost): string {
+        let output = "";
+        for (const diagnostic of diagnostics) {
+            if (diagnostic.file) {
+                const { start, length, file } = diagnostic;
+                const { line: firstLine, character: firstLineChar } = getLineAndCharacterOfPosition(file, start);
+                const { line: lastLine, character: lastLineChar } = getLineAndCharacterOfPosition(file, start + length);
+                const lastLineInFile = getLineAndCharacterOfPosition(file, file.text.length).line;
+                const relativeFileName = host ? convertToRelativePath(file.fileName, host.getCurrentDirectory(), fileName => host.getCanonicalFileName(fileName)) : file.fileName;
+
+                const hasMoreThanFiveLines = (lastLine - firstLine) >= 4;
+                let gutterWidth = (lastLine + 1 + "").length;
+                if (hasMoreThanFiveLines) {
+                    gutterWidth = Math.max(ellipsis.length, gutterWidth);
+                }
+
+                output += sys.newLine;
+                for (let i = firstLine; i <= lastLine; i++) {
+                    // If the error spans over 5 lines, we'll only show the first 2 and last 2 lines,
+                    // so we'll skip ahead to the second-to-last line.
+                    if (hasMoreThanFiveLines && firstLine + 1 < i && i < lastLine - 1) {
+                        output += formatAndReset(padLeft(ellipsis, gutterWidth), gutterStyleSequence) + gutterSeparator + sys.newLine;
+                        i = lastLine - 1;
+                    }
+
+                    const lineStart = getPositionOfLineAndCharacter(file, i, 0);
+                    const lineEnd = i < lastLineInFile ? getPositionOfLineAndCharacter(file, i + 1, 0) : file.text.length;
+                    let lineContent = file.text.slice(lineStart, lineEnd);
+                    lineContent = lineContent.replace(/\s+$/g, "");  // trim from end
+                    lineContent = lineContent.replace("\t", " ");    // convert tabs to single spaces
+
+                    // Output the gutter and the actual contents of the line.
+                    output += formatAndReset(padLeft(i + 1 + "", gutterWidth), gutterStyleSequence) + gutterSeparator;
+                    output += lineContent + sys.newLine;
+
+                    // Output the gutter and the error span for the line using tildes.
+                    output += formatAndReset(padLeft("", gutterWidth), gutterStyleSequence) + gutterSeparator;
+                    output += redForegroundEscapeSequence;
+                    if (i === firstLine) {
+                        // If we're on the last line, then limit it to the last character of the last line.
+                        // Otherwise, we'll just squiggle the rest of the line, giving 'slice' no end position.
+                        const lastCharForLine = i === lastLine ? lastLineChar : undefined;
+
+                        output += lineContent.slice(0, firstLineChar).replace(/\S/g, " ");
+                        output += lineContent.slice(firstLineChar, lastCharForLine).replace(/./g, "~");
+                    }
+                    else if (i === lastLine) {
+                        output += lineContent.slice(0, lastLineChar).replace(/./g, "~");
+                    }
+                    else {
+                        // Squiggle the entire line.
+                        output += lineContent.replace(/./g, "~");
+                    }
+                    output += resetEscapeSequence;
+
+                    output += sys.newLine;
+                }
+
+                output += sys.newLine;
+                output += `${ relativeFileName }(${ firstLine + 1 },${ firstLineChar + 1 }): `;
+            }
+
+            const categoryColor = getCategoryFormat(diagnostic.category);
+            const category = DiagnosticCategory[diagnostic.category].toLowerCase();
+            output += `${ formatAndReset(category, categoryColor) } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }`;
+        }
+        return output;
+    }
+
     export function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string {
         if (typeof messageText === "string") {
             return messageText;
@@ -298,6 +393,7 @@ namespace ts {
         let diagnosticsProducingTypeChecker: TypeChecker;
         let noDiagnosticsTypeChecker: TypeChecker;
         let classifiableNames: Map<string>;
+        let modifiedFilePaths: Path[] | undefined;
 
         const cachedSemanticDiagnosticsForFile: DiagnosticCache = {};
         const cachedDeclarationDiagnosticsForFile: DiagnosticCache = {};
@@ -367,7 +463,8 @@ namespace ts {
         // used to track cases when two file names differ only in casing
         const filesByNameIgnoreCase = host.useCaseSensitiveFileNames() ? createFileMap<SourceFile>(fileName => fileName.toLowerCase()) : undefined;
 
-        if (!tryReuseStructureFromOldProgram()) {
+        const structuralIsReused = tryReuseStructureFromOldProgram();
+        if (structuralIsReused !== StructureIsReused.Completely) {
             forEach(rootNames, name => processRootFile(name, /*isDefaultLib*/ false));
 
             // load type declarations specified via 'types' argument or implicitly from types/ and node_modules/@types folders
@@ -476,89 +573,114 @@ namespace ts {
         }
 
         interface OldProgramState {
-            program: Program;
+            program: Program | undefined;
             file: SourceFile;
+            /** The collection of paths modified *since* the old program. */
             modifiedFilePaths: Path[];
         }
 
-        function resolveModuleNamesReusingOldState(moduleNames: string[], containingFile: string, file: SourceFile, oldProgramState?: OldProgramState) {
-            if (!oldProgramState && !file.ambientModuleNames.length) {
-                // if old program state is not supplied and file does not contain locally defined ambient modules
-                // then the best we can do is fallback to the default logic
+        function resolveModuleNamesReusingOldState(moduleNames: string[], containingFile: string, file: SourceFile, oldProgramState: OldProgramState) {
+            if (structuralIsReused === StructureIsReused.Not && !file.ambientModuleNames.length) {
+                // If the old program state does not permit reusing resolutions and `file` does not contain locally defined ambient modules,
+                // the best we can do is fallback to the default logic.
                 return resolveModuleNamesWorker(moduleNames, containingFile);
             }
 
-            // at this point we know that either
+            const oldSourceFile = oldProgramState.program && oldProgramState.program.getSourceFile(containingFile);
+            if (oldSourceFile !== file && file.resolvedModules) {
+                // `file` was created for the new program.
+                //
+                // We only set `file.resolvedModules` via work from the current function,
+                // so it is defined iff we already called the current function on `file`.
+                // That call happened no later than the creation of the `file` object,
+                // which per above occured during the current program creation.
+                // Since we assume the filesystem does not change during program creation,
+                // it is safe to reuse resolutions from the earlier call.
+                const result: ResolvedModuleFull[] = [];
+                for (const moduleName of moduleNames) {
+                    const resolvedModule = file.resolvedModules.get(moduleName);
+                    result.push(resolvedModule);
+                }
+                return result;
+            }
+            // At this point, we know at least one of the following hold:
             // - file has local declarations for ambient modules
-            // OR
             // - old program state is available
-            // OR
-            // - both of items above
-            // With this it is possible that we can tell how some module names from the initial list will be resolved
-            // without doing actual resolution (in particular if some name was resolved to ambient module).
-            // Such names should be excluded from the list of module names that will be provided to `resolveModuleNamesWorker`
-            // since we don't want to resolve them again.
+            // With this information, we can infer some module resolutions without performing resolution.
 
-            // this is a list of modules for which we cannot predict resolution so they should be actually resolved
+            /** An ordered list of module names for which we cannot recover the resolution. */
             let unknownModuleNames: string[];
-            // this is a list of combined results assembles from predicted and resolved results.
-            // Order in this list matches the order in the original list of module names `moduleNames` which is important
-            // so later we can split results to resolutions of modules and resolutions of module augmentations.
+            /**
+             * The indexing of elements in this list matches that of `moduleNames`.
+             *
+             * Before combining results, result[i] is in one of the following states:
+             * * undefined: needs to be recomputed,
+             * * predictedToResolveToAmbientModuleMarker: known to be an ambient module.
+             * Needs to be reset to undefined before returning,
+             * * ResolvedModuleFull instance: can be reused.
+             */
             let result: ResolvedModuleFull[];
-            // a transient placeholder that is used to mark predicted resolution in the result list
+            /** A transient placeholder used to mark predicted resolution in the result list. */
             const predictedToResolveToAmbientModuleMarker: ResolvedModuleFull = <any>{};
 
+
             for (let i = 0; i < moduleNames.length; i++) {
                 const moduleName = moduleNames[i];
-                // module name is known to be resolved to ambient module if
-                // - module name is contained in the list of ambient modules that are locally declared in the file
-                // - in the old program module name was resolved to ambient module whose declaration is in non-modified file
+                // If we want to reuse resolutions more aggressively, we can refine this to check for whether the
+                // text of the corresponding modulenames has changed.
+                if (file === oldSourceFile) {
+                    const oldResolvedModule = oldSourceFile && oldSourceFile.resolvedModules.get(moduleName);
+                    if (oldResolvedModule) {
+                        if (isTraceEnabled(options, host)) {
+                            trace(host, Diagnostics.Reusing_resolution_of_module_0_to_file_1_from_old_program, moduleName, containingFile);
+                        }
+                        (result || (result = new Array(moduleNames.length)))[i] = oldResolvedModule;
+                        continue;
+                    }
+                }
+                // We know moduleName resolves to an ambient module provided that moduleName:
+                // - is in the list of ambient modules locally declared in the current source file.
+                // - resolved to an ambient module in the old program whose declaration is in an unmodified file
                 //   (so the same module declaration will land in the new program)
-                let isKnownToResolveToAmbientModule = false;
+                let resolvesToAmbientModuleInNonModifiedFile = false;
                 if (contains(file.ambientModuleNames, moduleName)) {
-                    isKnownToResolveToAmbientModule = true;
+                    resolvesToAmbientModuleInNonModifiedFile = true;
                     if (isTraceEnabled(options, host)) {
                         trace(host, Diagnostics.Module_0_was_resolved_as_locally_declared_ambient_module_in_file_1, moduleName, containingFile);
                     }
                 }
                 else {
-                    isKnownToResolveToAmbientModule = checkModuleNameResolvedToAmbientModuleInNonModifiedFile(moduleName, oldProgramState);
+                    resolvesToAmbientModuleInNonModifiedFile = moduleNameResolvesToAmbientModuleInNonModifiedFile(moduleName, oldProgramState);
                 }
 
-                if (isKnownToResolveToAmbientModule) {
-                    if (!unknownModuleNames) {
-                        // found a first module name for which result can be prediced
-                        // this means that this module name should not be passed to `resolveModuleNamesWorker`.
-                        // We'll use a separate list for module names that are definitely unknown.
-                        result = new Array(moduleNames.length);
-                        // copy all module names that appear before the current one in the list
-                        // since they are known to be unknown
-                        unknownModuleNames = moduleNames.slice(0, i);
-                    }
-                    // mark prediced resolution in the result list
-                    result[i] = predictedToResolveToAmbientModuleMarker;
+                if (resolvesToAmbientModuleInNonModifiedFile) {
+                    (result || (result = new Array(moduleNames.length)))[i] = predictedToResolveToAmbientModuleMarker;
                 }
-                else if (unknownModuleNames) {
-                    // found unknown module name and we are already using separate list for those - add it to the list
-                    unknownModuleNames.push(moduleName);
+                else {
+                    // Resolution failed in the old program, or resolved to an ambient module for which we can't reuse the result.
+                    (unknownModuleNames || (unknownModuleNames = [])).push(moduleName);
                 }
             }
 
-            if (!unknownModuleNames) {
-                // we've looked throught the list but have not seen any predicted resolution
-                // use default logic
-                return resolveModuleNamesWorker(moduleNames, containingFile);
-            }
-
-            const resolutions = unknownModuleNames.length
+            const resolutions = unknownModuleNames && unknownModuleNames.length
                 ? resolveModuleNamesWorker(unknownModuleNames, containingFile)
                 : emptyArray;
 
-            // combine results of resolutions and predicted results
+            // Combine results of resolutions and predicted results
+            if (!result) {
+                // There were no unresolved/ambient resolutions.
+                Debug.assert(resolutions.length === moduleNames.length);
+                return <ResolvedModuleFull[]>resolutions;
+            }
+
             let j = 0;
             for (let i = 0; i < result.length; i++) {
-                if (result[i] === predictedToResolveToAmbientModuleMarker) {
-                    result[i] = undefined;
+                if (result[i]) {
+                    // `result[i]` is either a `ResolvedModuleFull` or a marker.
+                    // If it is the former, we can leave it as is.
+                    if (result[i] === predictedToResolveToAmbientModuleMarker) {
+                        result[i] = undefined;
+                    }
                 }
                 else {
                     result[i] = resolutions[j];
@@ -566,18 +688,18 @@ namespace ts {
                 }
             }
             Debug.assert(j === resolutions.length);
+
             return result;
 
-            function checkModuleNameResolvedToAmbientModuleInNonModifiedFile(moduleName: string, oldProgramState?: OldProgramState): boolean {
-                if (!oldProgramState) {
-                    return false;
-                }
+            // If we change our policy of rechecking failed lookups on each program create,
+            // we should adjust the value returned here.
+            function moduleNameResolvesToAmbientModuleInNonModifiedFile(moduleName: string, oldProgramState: OldProgramState): boolean {
                 const resolutionToFile = getResolvedModule(oldProgramState.file, moduleName);
                 if (resolutionToFile) {
                     // module used to be resolved to file - ignore it
                     return false;
                 }
-                const ambientModule = oldProgram.getTypeChecker().tryFindAmbientModuleWithoutAugmentations(moduleName);
+                const ambientModule = oldProgramState.program && oldProgramState.program.getTypeChecker().tryFindAmbientModuleWithoutAugmentations(moduleName);
                 if (!(ambientModule && ambientModule.declarations)) {
                     return false;
                 }
@@ -599,99 +721,107 @@ namespace ts {
             }
         }
 
-        function tryReuseStructureFromOldProgram(): boolean {
+        function tryReuseStructureFromOldProgram(): StructureIsReused {
             if (!oldProgram) {
-                return false;
+                return StructureIsReused.Not;
             }
 
             // check properties that can affect structure of the program or module resolution strategy
             // if any of these properties has changed - structure cannot be reused
             const oldOptions = oldProgram.getCompilerOptions();
             if (changesAffectModuleResolution(oldOptions, options)) {
-                return false;
+                return oldProgram.structureIsReused = StructureIsReused.Not;
             }
 
-            Debug.assert(!oldProgram.structureIsReused);
+            Debug.assert(!(oldProgram.structureIsReused & (StructureIsReused.Completely | StructureIsReused.SafeModules)));
 
             // there is an old program, check if we can reuse its structure
             const oldRootNames = oldProgram.getRootFileNames();
             if (!arrayIsEqualTo(oldRootNames, rootNames)) {
-                return false;
+                return oldProgram.structureIsReused = StructureIsReused.Not;
             }
 
             if (!arrayIsEqualTo(options.types, oldOptions.types)) {
-                return false;
+                return oldProgram.structureIsReused = StructureIsReused.Not;
             }
 
             // check if program source files has changed in the way that can affect structure of the program
             const newSourceFiles: SourceFile[] = [];
             const filePaths: Path[] = [];
             const modifiedSourceFiles: { oldFile: SourceFile, newFile: SourceFile }[] = [];
+            oldProgram.structureIsReused = StructureIsReused.Completely;
 
             for (const oldSourceFile of oldProgram.getSourceFiles()) {
-                let newSourceFile = host.getSourceFileByPath
+                const newSourceFile = host.getSourceFileByPath
                     ? host.getSourceFileByPath(oldSourceFile.fileName, oldSourceFile.path, options.target)
                     : host.getSourceFile(oldSourceFile.fileName, options.target);
 
                 if (!newSourceFile) {
-                    return false;
+                    return oldProgram.structureIsReused = StructureIsReused.Not;
                 }
 
                 newSourceFile.path = oldSourceFile.path;
                 filePaths.push(newSourceFile.path);
 
                 if (oldSourceFile !== newSourceFile) {
+                    // The `newSourceFile` object was created for the new program.
+
                     if (oldSourceFile.hasNoDefaultLib !== newSourceFile.hasNoDefaultLib) {
                         // value of no-default-lib has changed
                         // this will affect if default library is injected into the list of files
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
 
                     // check tripleslash references
                     if (!arrayIsEqualTo(oldSourceFile.referencedFiles, newSourceFile.referencedFiles, fileReferenceIsEqualTo)) {
                         // tripleslash references has changed
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
 
                     // check imports and module augmentations
                     collectExternalModuleReferences(newSourceFile);
                     if (!arrayIsEqualTo(oldSourceFile.imports, newSourceFile.imports, moduleNameIsEqualTo)) {
                         // imports has changed
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
                     if (!arrayIsEqualTo(oldSourceFile.moduleAugmentations, newSourceFile.moduleAugmentations, moduleNameIsEqualTo)) {
                         // moduleAugmentations has changed
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
 
                     if (!arrayIsEqualTo(oldSourceFile.typeReferenceDirectives, newSourceFile.typeReferenceDirectives, fileReferenceIsEqualTo)) {
                         // 'types' references has changed
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
                     }
 
                     // tentatively approve the file
                     modifiedSourceFiles.push({ oldFile: oldSourceFile, newFile: newSourceFile });
                 }
-                else {
-                    // file has no changes - use it as is
-                    newSourceFile = oldSourceFile;
-                }
 
                 // if file has passed all checks it should be safe to reuse it
                 newSourceFiles.push(newSourceFile);
             }
 
-            const modifiedFilePaths = modifiedSourceFiles.map(f => f.newFile.path);
+            if (oldProgram.structureIsReused !== StructureIsReused.Completely) {
+                return oldProgram.structureIsReused;
+            }
+
+            modifiedFilePaths = modifiedSourceFiles.map(f => f.newFile.path);
             // try to verify results of module resolution
             for (const { oldFile: oldSourceFile, newFile: newSourceFile } of modifiedSourceFiles) {
                 const newSourceFilePath = getNormalizedAbsolutePath(newSourceFile.fileName, currentDirectory);
                 if (resolveModuleNamesWorker) {
                     const moduleNames = map(concatenate(newSourceFile.imports, newSourceFile.moduleAugmentations), getTextOfLiteral);
-                    const resolutions = resolveModuleNamesReusingOldState(moduleNames, newSourceFilePath, newSourceFile, { file: oldSourceFile, program: oldProgram, modifiedFilePaths });
+                    const oldProgramState = { program: oldProgram, file: oldSourceFile, modifiedFilePaths };
+                    const resolutions = resolveModuleNamesReusingOldState(moduleNames, newSourceFilePath, newSourceFile, oldProgramState);
                     // ensure that module resolution results are still correct
                     const resolutionsChanged = hasChangesInResolutions(moduleNames, resolutions, oldSourceFile.resolvedModules, moduleResolutionIsEqualTo);
                     if (resolutionsChanged) {
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
+                        newSourceFile.resolvedModules = zipToMap(moduleNames, resolutions);
+                    }
+                    else {
+                        newSourceFile.resolvedModules = oldSourceFile.resolvedModules;
                     }
                 }
                 if (resolveTypeReferenceDirectiveNamesWorker) {
@@ -700,12 +830,17 @@ namespace ts {
                     // ensure that types resolutions are still correct
                     const resolutionsChanged = hasChangesInResolutions(typesReferenceDirectives, resolutions, oldSourceFile.resolvedTypeReferenceDirectiveNames, typeDirectiveIsEqualTo);
                     if (resolutionsChanged) {
-                        return false;
+                        oldProgram.structureIsReused = StructureIsReused.SafeModules;
+                        newSourceFile.resolvedTypeReferenceDirectiveNames = zipToMap(typesReferenceDirectives, resolutions);
+                    }
+                    else {
+                        newSourceFile.resolvedTypeReferenceDirectiveNames = oldSourceFile.resolvedTypeReferenceDirectiveNames;
                     }
                 }
-                // pass the cache of module/types resolutions from the old source file
-                newSourceFile.resolvedModules = oldSourceFile.resolvedModules;
-                newSourceFile.resolvedTypeReferenceDirectiveNames = oldSourceFile.resolvedTypeReferenceDirectiveNames;
+            }
+
+            if (oldProgram.structureIsReused !== StructureIsReused.Completely) {
+                return oldProgram.structureIsReused;
             }
 
             // update fileName -> file mapping
@@ -720,9 +855,8 @@ namespace ts {
                 fileProcessingDiagnostics.reattachFileDiagnostics(modifiedFile.newFile);
             }
             resolvedTypeReferenceDirectives = oldProgram.getResolvedTypeReferenceDirectives();
-            oldProgram.structureIsReused = true;
 
-            return true;
+            return oldProgram.structureIsReused = StructureIsReused.Completely;
         }
 
         function getEmitHost(writeFileCallback?: WriteFileCallback): EmitHost {
@@ -1175,7 +1309,7 @@ namespace ts {
         }
 
         function getDeclarationDiagnosticsForFile(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
-            return isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
+            return sourceFile.isDeclarationFile ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
         }
 
         function getOptionsDiagnostics(): Diagnostic[] {
@@ -1214,7 +1348,6 @@ namespace ts {
 
             const isJavaScriptFile = isSourceFileJavaScript(file);
             const isExternalModuleFile = isExternalModule(file);
-            const isDtsFile = isDeclarationFile(file);
 
             let imports: LiteralExpression[];
             let moduleAugmentations: LiteralExpression[];
@@ -1267,7 +1400,7 @@ namespace ts {
                         }
                         break;
                     case SyntaxKind.ModuleDeclaration:
-                        if (isAmbientModule(<ModuleDeclaration>node) && (inAmbientModule || hasModifier(node, ModifierFlags.Ambient) || isDeclarationFile(file))) {
+                        if (isAmbientModule(<ModuleDeclaration>node) && (inAmbientModule || hasModifier(node, ModifierFlags.Ambient) || file.isDeclarationFile)) {
                             const moduleName = <LiteralExpression>(<ModuleDeclaration>node).name;
                             // Ambient module declarations can be interpreted as augmentations for some existing external modules.
                             // This will happen in two cases:
@@ -1278,7 +1411,7 @@ namespace ts {
                                 (moduleAugmentations || (moduleAugmentations = [])).push(moduleName);
                             }
                             else if (!inAmbientModule) {
-                                if (isDtsFile) {
+                                if (file.isDeclarationFile) {
                                     // for global .d.ts files record name of ambient module
                                     (ambientModules || (ambientModules = [])).push(moduleName.text);
                                 }
@@ -1528,11 +1661,11 @@ namespace ts {
         function processImportedModules(file: SourceFile) {
             collectExternalModuleReferences(file);
             if (file.imports.length || file.moduleAugmentations.length) {
-                file.resolvedModules = createMap<ResolvedModuleFull>();
                 // Because global augmentation doesn't have string literal name, we can check for global augmentation as such.
                 const nonGlobalAugmentation = filter(file.moduleAugmentations, (moduleAugmentation) => moduleAugmentation.kind === SyntaxKind.StringLiteral);
                 const moduleNames = map(concatenate(file.imports, nonGlobalAugmentation), getTextOfLiteral);
-                const resolutions = resolveModuleNamesReusingOldState(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory), file);
+                const oldProgramState = { program: oldProgram, file, modifiedFilePaths };
+                const resolutions = resolveModuleNamesReusingOldState(moduleNames, getNormalizedAbsolutePath(file.fileName, currentDirectory), file, oldProgramState);
                 Debug.assert(resolutions.length === moduleNames.length);
                 for (let i = 0; i < moduleNames.length; i++) {
                     const resolution = resolutions[i];
@@ -1596,7 +1729,7 @@ namespace ts {
                 const absoluteRootDirectoryPath = host.getCanonicalFileName(getNormalizedAbsolutePath(rootDirectory, currentDirectory));
 
                 for (const sourceFile of sourceFiles) {
-                    if (!isDeclarationFile(sourceFile)) {
+                    if (!sourceFile.isDeclarationFile) {
                         const absoluteSourceFilePath = host.getCanonicalFileName(getNormalizedAbsolutePath(sourceFile.fileName, currentDirectory));
                         if (absoluteSourceFilePath.indexOf(absoluteRootDirectoryPath) !== 0) {
                             programDiagnostics.add(createCompilerDiagnostic(Diagnostics.File_0_is_not_under_rootDir_1_rootDir_is_expected_to_contain_all_source_files, sourceFile.fileName, options.rootDir));
@@ -1709,13 +1842,13 @@ namespace ts {
             const languageVersion = options.target || ScriptTarget.ES3;
             const outFile = options.outFile || options.out;
 
-            const firstNonAmbientExternalModuleSourceFile = forEach(files, f => isExternalModule(f) && !isDeclarationFile(f) ? f : undefined);
+            const firstNonAmbientExternalModuleSourceFile = forEach(files, f => isExternalModule(f) && !f.isDeclarationFile ? f : undefined);
             if (options.isolatedModules) {
                 if (options.module === ModuleKind.None && languageVersion < ScriptTarget.ES2015) {
                     programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_isolatedModules_can_only_be_used_when_either_option_module_is_provided_or_option_target_is_ES2015_or_higher));
                 }
 
-                const firstNonExternalModuleSourceFile = forEach(files, f => !isExternalModule(f) && !isDeclarationFile(f) ? f : undefined);
+                const firstNonExternalModuleSourceFile = forEach(files, f => !isExternalModule(f) && !f.isDeclarationFile ? f : undefined);
                 if (firstNonExternalModuleSourceFile) {
                     const span = getErrorSpanForNode(firstNonExternalModuleSourceFile, firstNonExternalModuleSourceFile);
                     programDiagnostics.add(createFileDiagnostic(firstNonExternalModuleSourceFile, span.start, span.length, Diagnostics.Cannot_compile_namespaces_when_the_isolatedModules_flag_is_provided));

src/compiler/scanner.ts

@@ -712,11 +712,11 @@ namespace ts {
         return accumulator;
     }
 
-    export function forEachLeadingCommentRange<T, U>(text: string, pos: number, cb: (pos: number, end: number, kind: CommentKind, hasTrailingNewLine: boolean, state: T) => U, state?: T) {
+    export function forEachLeadingCommentRange<T, U>(text: string, pos: number, cb: (pos: number, end: number, kind: CommentKind, hasTrailingNewLine: boolean, state: T) => U, state?: T): U | undefined {
         return iterateCommentRanges(/*reduce*/ false, text, pos, /*trailing*/ false, cb, state);
     }
 
-    export function forEachTrailingCommentRange<T, U>(text: string, pos: number, cb: (pos: number, end: number, kind: CommentKind, hasTrailingNewLine: boolean, state: T) => U, state?: T) {
+    export function forEachTrailingCommentRange<T, U>(text: string, pos: number, cb: (pos: number, end: number, kind: CommentKind, hasTrailingNewLine: boolean, state: T) => U, state?: T): U | undefined {
         return iterateCommentRanges(/*reduce*/ false, text, pos, /*trailing*/ true, cb, state);
     }
 
@@ -746,10 +746,11 @@ namespace ts {
     }
 
     /** Optionally, get the shebang */
-    export function getShebang(text: string): string {
-        return shebangTriviaRegex.test(text)
-            ? shebangTriviaRegex.exec(text)[0]
-            : undefined;
+    export function getShebang(text: string): string | undefined {
+        const match = shebangTriviaRegex.exec(text);
+        if (match) {
+            return match[0];
+        }
     }
 
     export function isIdentifierStart(ch: number, languageVersion: ScriptTarget): boolean {

src/compiler/transformer.ts

@@ -165,7 +165,7 @@ namespace ts {
         };
 
         function transformRoot(node: T) {
-            return node && (!isSourceFile(node) || !isDeclarationFile(node)) ? transformation(node) : node;
+            return node && (!isSourceFile(node) || !node.isDeclarationFile) ? transformation(node) : node;
         }
 
         /**

src/compiler/transformers/es2015.ts

@@ -295,7 +295,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 
@@ -813,7 +813,7 @@ namespace ts {
 
             // Create a synthetic text range for the return statement.
             const closingBraceLocation = createTokenRange(skipTrivia(currentText, node.members.end), SyntaxKind.CloseBraceToken);
-            const localName = getLocalName(node);
+            const localName = getInternalName(node);
 
             // The following partially-emitted expression exists purely to align our sourcemap
             // emit with the original emitter.
@@ -870,7 +870,7 @@ namespace ts {
                 /*decorators*/ undefined,
                 /*modifiers*/ undefined,
                 /*asteriskToken*/ undefined,
-                getDeclarationName(node),
+                getInternalName(node),
                 /*typeParameters*/ undefined,
                 transformConstructorParameters(constructor, hasSynthesizedSuper),
                 /*type*/ undefined,
@@ -2009,13 +2009,14 @@ namespace ts {
                         }
                         else {
                             assignment = createBinary(<Identifier>decl.name, SyntaxKind.EqualsToken, visitNode(decl.initializer, visitor, isExpression));
+                            setTextRange(assignment, decl);
                         }
 
                         assignments = append(assignments, assignment);
                     }
                 }
                 if (assignments) {
-                    updated = setTextRange(createStatement(reduceLeft(assignments, (acc, v) => createBinary(v, SyntaxKind.CommaToken, acc))), node);
+                    updated = setTextRange(createStatement(inlineExpressions(assignments)), node);
                 }
                 else {
                     // none of declarations has initializer - the entire variable statement can be deleted
@@ -3180,7 +3181,20 @@ namespace ts {
             const savedConvertedLoopState = convertedLoopState;
             convertedLoopState = undefined;
             const ancestorFacts = enterSubtree(HierarchyFacts.FunctionExcludes, HierarchyFacts.FunctionIncludes);
-            const updated = visitEachChild(node, visitor, context);
+            let updated: AccessorDeclaration;
+            if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis) {
+                const parameters = visitParameterList(node.parameters, visitor, context);
+                const body = transformFunctionBody(node);
+                if (node.kind === SyntaxKind.GetAccessor) {
+                    updated = updateGetAccessor(node, node.decorators, node.modifiers, node.name, parameters, node.type, body);
+                }
+                else {
+                    updated = updateSetAccessor(node, node.decorators, node.modifiers, node.name, parameters, body);
+                }
+            }
+            else {
+                updated = visitEachChild(node, visitor, context);
+            }
             exitSubtree(ancestorFacts, HierarchyFacts.PropagateNewTargetMask, HierarchyFacts.None);
             convertedLoopState = savedConvertedLoopState;
             return updated;
@@ -3712,7 +3726,7 @@ namespace ts {
         function substituteIdentifier(node: Identifier) {
             // Only substitute the identifier if we have enabled substitutions for block-scoped
             // bindings.
-            if (enabledSubstitutions & ES2015SubstitutionFlags.BlockScopedBindings) {
+            if (enabledSubstitutions & ES2015SubstitutionFlags.BlockScopedBindings && !isInternalName(node)) {
                 const original = getParseTreeNode(node, isIdentifier);
                 if (original && isNameOfDeclarationWithCollidingName(original)) {
                     return setTextRange(getGeneratedNameForNode(original), node);
@@ -3735,7 +3749,7 @@ namespace ts {
                 case SyntaxKind.ClassDeclaration:
                 case SyntaxKind.EnumDeclaration:
                 case SyntaxKind.VariableDeclaration:
-                    return (<Declaration>parent).name === node
+                    return (<NamedDeclaration>parent).name === node
                         && resolver.isDeclarationWithCollidingName(<Declaration>parent);
             }
 
@@ -3765,16 +3779,42 @@ namespace ts {
          * @param node An Identifier node.
          */
         function substituteExpressionIdentifier(node: Identifier): Identifier {
-            if (enabledSubstitutions & ES2015SubstitutionFlags.BlockScopedBindings) {
+            if (enabledSubstitutions & ES2015SubstitutionFlags.BlockScopedBindings && !isInternalName(node)) {
                 const declaration = resolver.getReferencedDeclarationWithCollidingName(node);
-                if (declaration) {
-                    return setTextRange(getGeneratedNameForNode(declaration.name), node);
+                if (declaration && !(isClassLike(declaration) && isPartOfClassBody(declaration, node))) {
+                    return setTextRange(getGeneratedNameForNode(getNameOfDeclaration(declaration)), node);
                 }
             }
 
             return node;
         }
 
+        function isPartOfClassBody(declaration: ClassLikeDeclaration, node: Identifier) {
+            let currentNode = getParseTreeNode(node);
+            if (!currentNode || currentNode === declaration || currentNode.end <= declaration.pos || currentNode.pos >= declaration.end) {
+                // if the node has no correlation to a parse tree node, its definitely not
+                // part of the body.
+                // if the node is outside of the document range of the declaration, its
+                // definitely not part of the body.
+                return false;
+            }
+            const blockScope = getEnclosingBlockScopeContainer(declaration);
+            while (currentNode) {
+                if (currentNode === blockScope || currentNode === declaration) {
+                    // if we are in the enclosing block scope of the declaration, we are definitely
+                    // not inside the class body.
+                    return false;
+                }
+                if (isClassElement(currentNode) && currentNode.parent === declaration) {
+                    // we are in the class body, but we treat static fields as outside of the class body
+                    return currentNode.kind !== SyntaxKind.PropertyDeclaration
+                        || (getModifierFlags(currentNode) & ModifierFlags.Static) === 0;
+                }
+                currentNode = currentNode.parent;
+            }
+            return false;
+        }
+
         /**
          * Substitutes `this` when contained within an arrow function.
          *
@@ -3789,8 +3829,9 @@ namespace ts {
         }
 
         function getClassMemberPrefix(node: ClassExpression | ClassDeclaration, member: ClassElement) {
-            const expression = getLocalName(node);
-            return hasModifier(member, ModifierFlags.Static) ? expression : createPropertyAccess(expression, "prototype");
+            return hasModifier(member, ModifierFlags.Static)
+                ? getInternalName(node)
+                : createPropertyAccess(getInternalName(node), "prototype");
         }
 
         function hasSynthesizedDefaultSuperCall(constructor: ConstructorDeclaration, hasExtendsClause: boolean) {

src/compiler/transformers/es2016.ts

@@ -9,7 +9,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 

src/compiler/transformers/es2017.ts

@@ -47,7 +47,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 

src/compiler/transformers/esnext.ts

@@ -33,7 +33,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 
@@ -106,15 +106,11 @@ namespace ts {
             }
         }
 
-        function visitAwaitExpression(node: AwaitExpression) {
+        function visitAwaitExpression(node: AwaitExpression): Expression {
             if (enclosingFunctionFlags & FunctionFlags.Async && enclosingFunctionFlags & FunctionFlags.Generator) {
-                const expression = visitNode(node.expression, visitor, isExpression);
                 return setOriginalNode(
                     setTextRange(
-                        createYield(
-                            /*asteriskToken*/ undefined,
-                            createArrayLiteral([createLiteral("await"), expression])
-                        ),
+                        createYield(createAwaitHelper(context, visitNode(node.expression, visitor, isExpression))),
                         /*location*/ node
                     ),
                     node
@@ -124,18 +120,26 @@ namespace ts {
         }
 
         function visitYieldExpression(node: YieldExpression) {
-            if (enclosingFunctionFlags & FunctionFlags.Async && enclosingFunctionFlags & FunctionFlags.Generator) {
+            if (enclosingFunctionFlags & FunctionFlags.Async && enclosingFunctionFlags & FunctionFlags.Generator && node.asteriskToken) {
                 const expression = visitNode(node.expression, visitor, isExpression);
-                return updateYield(
-                    node,
-                    node.asteriskToken,
-                    node.asteriskToken
-                        ? createAsyncDelegatorHelper(context, expression, expression)
-                        : createArrayLiteral(
-                            expression
-                            ? [createLiteral("yield"), expression]
-                            : [createLiteral("yield")]
-                        )
+                return setOriginalNode(
+                    setTextRange(
+                        createYield(
+                            createAwaitHelper(context,
+                                updateYield(
+                                    node,
+                                    node.asteriskToken,
+                                    createAsyncDelegatorHelper(
+                                        context,
+                                        createAsyncValuesHelper(context, expression, expression),
+                                        expression
+                                    )
+                                )
+                            )
+                        ),
+                        node
+                    ),
+                    node
                 );
             }
             return visitEachChild(node, visitor, context);
@@ -347,6 +351,10 @@ namespace ts {
             );
         }
 
+        function awaitAsYield(expression: Expression) {
+            return createYield(/*asteriskToken*/ undefined, enclosingFunctionFlags & FunctionFlags.Generator ? createAwaitHelper(context, expression) : expression);
+        }
+
         function transformForAwaitOfStatement(node: ForOfStatement, outermostLabeledStatement: LabeledStatement) {
             const expression = visitNode(node.expression, visitor, isExpression);
             const iterator = isIdentifier(expression) ? getGeneratedNameForNode(expression) : createTempVariable(/*recordTempVariable*/ undefined);
@@ -354,16 +362,11 @@ namespace ts {
             const errorRecord = createUniqueName("e");
             const catchVariable = getGeneratedNameForNode(errorRecord);
             const returnMethod = createTempVariable(/*recordTempVariable*/ undefined);
-            const values = createAsyncValuesHelper(context, expression, /*location*/ node.expression);
-            const next = createYield(
-                /*asteriskToken*/ undefined,
-                enclosingFunctionFlags & FunctionFlags.Generator
-                    ? createArrayLiteral([
-                        createLiteral("await"),
-                        createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, [])
-                    ])
-                    : createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, [])
-            );
+            const callValues = createAsyncValuesHelper(context, expression, /*location*/ node.expression);
+            const callNext = createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, []);
+            const getDone = createPropertyAccess(result, "done");
+            const getValue = createPropertyAccess(result, "value");
+            const callReturn = createFunctionCall(returnMethod, iterator, []);
 
             hoistVariableDeclaration(errorRecord);
             hoistVariableDeclaration(returnMethod);
@@ -374,16 +377,19 @@ namespace ts {
                         /*initializer*/ setEmitFlags(
                             setTextRange(
                                 createVariableDeclarationList([
-                                    setTextRange(createVariableDeclaration(iterator, /*type*/ undefined, values), node.expression),
-                                    createVariableDeclaration(result, /*type*/ undefined, next)
+                                    setTextRange(createVariableDeclaration(iterator, /*type*/ undefined, callValues), node.expression),
+                                    createVariableDeclaration(result)
                                 ]),
                                 node.expression
                             ),
                             EmitFlags.NoHoisting
                         ),
-                        /*condition*/ createLogicalNot(createPropertyAccess(result, "done")),
-                        /*incrementor*/ createAssignment(result, next),
-                        /*statement*/ convertForOfStatementHead(node, createPropertyAccess(result, "value"))
+                        /*condition*/ createComma(
+                            createAssignment(result, awaitAsYield(callNext)),
+                            createLogicalNot(getDone)
+                        ),
+                        /*incrementor*/ undefined,
+                        /*statement*/ convertForOfStatementHead(node, awaitAsYield(getValue))
                     ),
                     /*location*/ node
                 ),
@@ -421,26 +427,14 @@ namespace ts {
                                     createLogicalAnd(
                                         createLogicalAnd(
                                             result,
-                                            createLogicalNot(
-                                                createPropertyAccess(result, "done")
-                                            )
+                                            createLogicalNot(getDone)
                                         ),
                                         createAssignment(
                                             returnMethod,
                                             createPropertyAccess(iterator, "return")
                                         )
                                     ),
-                                    createStatement(
-                                        createYield(
-                                            /*asteriskToken*/ undefined,
-                                            enclosingFunctionFlags & FunctionFlags.Generator
-                                                ? createArrayLiteral([
-                                                    createLiteral("await"),
-                                                    createFunctionCall(returnMethod, iterator, [])
-                                                ])
-                                                : createFunctionCall(returnMethod, iterator, [])
-                                        )
-                                    )
+                                    createStatement(awaitAsYield(callReturn))
                                 ),
                                 EmitFlags.SingleLine
                             )
@@ -880,27 +874,39 @@ namespace ts {
         );
     }
 
+    const awaitHelper: EmitHelper = {
+        name: "typescript:await",
+        scoped: false,
+        text: `
+            var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
+        `
+    };
+
+    function createAwaitHelper(context: TransformationContext, expression: Expression) {
+        context.requestEmitHelper(awaitHelper);
+        return createCall(getHelperName("__await"), /*typeArguments*/ undefined, [expression]);
+    }
+
     const asyncGeneratorHelper: EmitHelper = {
         name: "typescript:asyncGenerator",
         scoped: false,
         text: `
             var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
                 if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
-                var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
-                return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
-                function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
-                function next() { if (!c && q.length) resume((c = q.shift())[0], c[1]); }
-                function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(c[3], e); } }
-                function step(r) { r.done ? settle(c[2], r) : Promise.resolve(r.value[1]).then(r.value[0] === "yield" ? send : fulfill, reject); }
-                function send(value) { settle(c[2], { value: value, done: false }); }
+                var g = generator.apply(thisArg, _arguments || []), i, q = [];
+                return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
+                function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
+                function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
+                function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r);  }
                 function fulfill(value) { resume("next", value); }
                 function reject(value) { resume("throw", value); }
-                function settle(f, v) { c = void 0, f(v), next(); }
+                function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
             };
         `
     };
 
     function createAsyncGeneratorHelper(context: TransformationContext, generatorFunc: FunctionExpression) {
+        context.requestEmitHelper(awaitHelper);
         context.requestEmitHelper(asyncGeneratorHelper);
 
         // Mark this node as originally an async function
@@ -922,16 +928,16 @@ namespace ts {
         scoped: false,
         text: `
             var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
-                var i = { next: verb("next"), "throw": verb("throw", function (e) { throw e; }), "return": verb("return", function (v) { return { value: v, done: true }; }) }, p;
-                return o = __asyncValues(o), i[Symbol.iterator] = function () { return this; }, i;
-                function verb(n, f) { return function (v) { return v = p && n === "throw" ? f(v) : p && v.done ? v : { value: p ? ["yield", v.value] : ["await", (o[n] || f).call(o, v)], done: false }, p = !p, v; }; }
+                var i, p;
+                return i = {}, verb("next"), verb("throw", function (e) { throw e; }), verb("return"), i[Symbol.iterator] = function () { return this; }, i;
+                function verb(n, f) { if (o[n]) i[n] = function (v) { return (p = !p) ? { value: __await(o[n](v)), done: n === "return" } : f ? f(v) : v; }; }
             };
         `
     };
 
     function createAsyncDelegatorHelper(context: TransformationContext, expression: Expression, location?: TextRange) {
+        context.requestEmitHelper(awaitHelper);
         context.requestEmitHelper(asyncDelegator);
-        context.requestEmitHelper(asyncValues);
         return setTextRange(
             createCall(
                 getHelperName("__asyncDelegator"),

src/compiler/transformers/generators.ts

@@ -293,8 +293,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)
-                || (node.transformFlags & TransformFlags.ContainsGenerator) === 0) {
+            if (node.isDeclarationFile || (node.transformFlags & TransformFlags.ContainsGenerator) === 0) {
                 return node;
             }
 

src/compiler/transformers/jsx.ts

@@ -15,7 +15,7 @@ namespace ts {
          * @param node A SourceFile node.
          */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 

src/compiler/transformers/module/es2015.ts

@@ -16,7 +16,7 @@ namespace ts {
         return transformSourceFile;
 
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 

src/compiler/transformers/module/module.ts

@@ -55,7 +55,7 @@ namespace ts {
          * @param node The SourceFile node.
          */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node) || !(isExternalModule(node) || compilerOptions.isolatedModules)) {
+            if (node.isDeclarationFile || !(isExternalModule(node) || compilerOptions.isolatedModules)) {
                 return node;
             }
 

src/compiler/transformers/module/system.ts

@@ -50,9 +50,7 @@ namespace ts {
          * @param node The SourceFile node.
          */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)
-                || !(isExternalModule(node)
-                    || compilerOptions.isolatedModules)) {
+            if (node.isDeclarationFile || !(isExternalModule(node) || compilerOptions.isolatedModules)) {
                 return node;
             }
 

src/compiler/transformers/ts.ts

@@ -76,7 +76,7 @@ namespace ts {
          * @param node A SourceFile node.
          */
         function transformSourceFile(node: SourceFile) {
-            if (isDeclarationFile(node)) {
+            if (node.isDeclarationFile) {
                 return node;
             }
 
@@ -1762,23 +1762,19 @@ namespace ts {
         }
 
         function serializeUnionOrIntersectionType(node: UnionOrIntersectionTypeNode): SerializedTypeNode {
+            // Note when updating logic here also update getEntityNameForDecoratorMetadata
+            // so that aliases can be marked as referenced
             let serializedUnion: SerializedTypeNode;
             for (const typeNode of node.types) {
                 const serializedIndividual = serializeTypeNode(typeNode);
 
-                if (isVoidExpression(serializedIndividual)) {
-                    // If we dont have any other type already set, set the initial type
-                    if (!serializedUnion) {
-                        serializedUnion = serializedIndividual;
-                    }
-                }
-                else if (isIdentifier(serializedIndividual) && serializedIndividual.text === "Object") {
+                if (isIdentifier(serializedIndividual) && serializedIndividual.text === "Object") {
                     // One of the individual is global object, return immediately
                     return serializedIndividual;
                 }
                 // If there exists union that is not void 0 expression, check if the the common type is identifier.
                 // anything more complex and we will just default to Object
-                else if (serializedUnion && !isVoidExpression(serializedUnion)) {
+                else if (serializedUnion) {
                     // Different types
                     if (!isIdentifier(serializedUnion) ||
                         !isIdentifier(serializedIndividual) ||
@@ -2606,14 +2602,16 @@ namespace ts {
          * Adds a leading VariableStatement for a enum or module declaration.
          */
         function addVarForEnumOrModuleDeclaration(statements: Statement[], node: ModuleDeclaration | EnumDeclaration) {
-            // Emit a variable statement for the module.
+            // Emit a variable statement for the module. We emit top-level enums as a `var`
+            // declaration to avoid static errors in global scripts scripts due to redeclaration.
+            // enums in any other scope are emitted as a `let` declaration.
             const statement = createVariableStatement(
                 visitNodes(node.modifiers, modifierVisitor, isModifier),
-                [
+                createVariableDeclarationList([
                     createVariableDeclaration(
                         getLocalName(node, /*allowComments*/ false, /*allowSourceMaps*/ true)
                     )
-                ]
+                ], currentScope.kind === SyntaxKind.SourceFile ? NodeFlags.None : NodeFlags.Let)
             );
 
             setOriginalNode(statement, node);
@@ -2925,7 +2923,7 @@ namespace ts {
         function visitExportDeclaration(node: ExportDeclaration): VisitResult<Statement> {
             if (!node.exportClause) {
                 // Elide a star export if the module it references does not export a value.
-                return resolver.moduleExportsSomeValue(node.moduleSpecifier) ? node : undefined;
+                return compilerOptions.isolatedModules || resolver.moduleExportsSomeValue(node.moduleSpecifier) ? node : undefined;
             }
 
             if (!resolver.isValueAliasDeclaration(node)) {

src/compiler/tsc.ts

@@ -60,93 +60,8 @@ namespace ts {
         sys.write(ts.formatDiagnostics([diagnostic], host));
     }
 
-    const redForegroundEscapeSequence = "\u001b[91m";
-    const yellowForegroundEscapeSequence = "\u001b[93m";
-    const blueForegroundEscapeSequence = "\u001b[93m";
-    const gutterStyleSequence = "\u001b[100;30m";
-    const gutterSeparator = " ";
-    const resetEscapeSequence = "\u001b[0m";
-    const ellipsis = "...";
-    function getCategoryFormat(category: DiagnosticCategory): string {
-        switch (category) {
-            case DiagnosticCategory.Warning: return yellowForegroundEscapeSequence;
-            case DiagnosticCategory.Error: return redForegroundEscapeSequence;
-            case DiagnosticCategory.Message: return blueForegroundEscapeSequence;
-        }
-    }
-
-    function formatAndReset(text: string, formatStyle: string) {
-        return formatStyle + text + resetEscapeSequence;
-    }
-
     function reportDiagnosticWithColorAndContext(diagnostic: Diagnostic, host: FormatDiagnosticsHost): void {
-        let output = "";
-
-        if (diagnostic.file) {
-            const { start, length, file } = diagnostic;
-            const { line: firstLine, character: firstLineChar } = getLineAndCharacterOfPosition(file, start);
-            const { line: lastLine, character: lastLineChar } = getLineAndCharacterOfPosition(file, start + length);
-            const lastLineInFile = getLineAndCharacterOfPosition(file, file.text.length).line;
-            const relativeFileName = host ? convertToRelativePath(file.fileName, host.getCurrentDirectory(), fileName => host.getCanonicalFileName(fileName)) : file.fileName;
-
-            const hasMoreThanFiveLines = (lastLine - firstLine) >= 4;
-            let gutterWidth = (lastLine + 1 + "").length;
-            if (hasMoreThanFiveLines) {
-                gutterWidth = Math.max(ellipsis.length, gutterWidth);
-            }
-
-            output += sys.newLine;
-            for (let i = firstLine; i <= lastLine; i++) {
-                // If the error spans over 5 lines, we'll only show the first 2 and last 2 lines,
-                // so we'll skip ahead to the second-to-last line.
-                if (hasMoreThanFiveLines && firstLine + 1 < i && i < lastLine - 1) {
-                    output += formatAndReset(padLeft(ellipsis, gutterWidth), gutterStyleSequence) + gutterSeparator + sys.newLine;
-                    i = lastLine - 1;
-                }
-
-                const lineStart = getPositionOfLineAndCharacter(file, i, 0);
-                const lineEnd = i < lastLineInFile ? getPositionOfLineAndCharacter(file, i + 1, 0) : file.text.length;
-                let lineContent = file.text.slice(lineStart, lineEnd);
-                lineContent = lineContent.replace(/\s+$/g, "");  // trim from end
-                lineContent = lineContent.replace("\t", " ");    // convert tabs to single spaces
-
-                // Output the gutter and the actual contents of the line.
-                output += formatAndReset(padLeft(i + 1 + "", gutterWidth), gutterStyleSequence) + gutterSeparator;
-                output += lineContent + sys.newLine;
-
-                // Output the gutter and the error span for the line using tildes.
-                output += formatAndReset(padLeft("", gutterWidth), gutterStyleSequence) + gutterSeparator;
-                output += redForegroundEscapeSequence;
-                if (i === firstLine) {
-                    // If we're on the last line, then limit it to the last character of the last line.
-                    // Otherwise, we'll just squiggle the rest of the line, giving 'slice' no end position.
-                    const lastCharForLine = i === lastLine ? lastLineChar : undefined;
-
-                    output += lineContent.slice(0, firstLineChar).replace(/\S/g, " ");
-                    output += lineContent.slice(firstLineChar, lastCharForLine).replace(/./g, "~");
-                }
-                else if (i === lastLine) {
-                    output += lineContent.slice(0, lastLineChar).replace(/./g, "~");
-                }
-                else {
-                    // Squiggle the entire line.
-                    output += lineContent.replace(/./g, "~");
-                }
-                output += resetEscapeSequence;
-
-                output += sys.newLine;
-            }
-
-            output += sys.newLine;
-            output += `${ relativeFileName }(${ firstLine + 1 },${ firstLineChar + 1 }): `;
-        }
-
-        const categoryColor = getCategoryFormat(diagnostic.category);
-        const category = DiagnosticCategory[diagnostic.category].toLowerCase();
-        output += `${ formatAndReset(category, categoryColor) } TS${ diagnostic.code }: ${ flattenDiagnosticMessageText(diagnostic.messageText, sys.newLine) }`;
-        output += sys.newLine + sys.newLine;
-
-        sys.write(output);
+        sys.write(ts.formatDiagnosticsWithColorAndContext([diagnostic], host) + sys.newLine + sys.newLine);
     }
 
     function reportWatchDiagnostic(diagnostic: Diagnostic) {

src/compiler/types.ts

@@ -389,6 +389,7 @@ namespace ts {
         // Transformation nodes
         NotEmittedStatement,
         PartiallyEmittedExpression,
+        CommaListExpression,
         MergeDeclarationMarker,
         EndOfDeclarationMarker,
 
@@ -571,11 +572,16 @@ namespace ts {
 
     export interface Identifier extends PrimaryExpression {
         kind: SyntaxKind.Identifier;
-        text: string;                                  // Text of identifier (with escapes converted to characters)
-        originalKeywordKind?: SyntaxKind;              // Original syntaxKind which get set so that we can report an error later
+        /**
+         * Text of identifier (with escapes converted to characters).
+         * If the identifier begins with two underscores, this will begin with three.
+         */
+        text: string;
+        originalKeywordKind?: SyntaxKind;                         // Original syntaxKind which get set so that we can report an error later
         /*@internal*/ autoGenerateKind?: GeneratedIdentifierKind; // Specifies whether to auto-generate the text for an identifier.
-        /*@internal*/ autoGenerateId?: number;         // Ensures unique generated identifiers get unique names, but clones get the same name.
-        isInJSDocNamespace?: boolean;                  // if the node is a member in a JSDoc namespace
+        /*@internal*/ autoGenerateId?: number;                    // Ensures unique generated identifiers get unique names, but clones get the same name.
+        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.
     }
 
     // Transient identifier node (marked by id === -1)
@@ -605,10 +611,13 @@ namespace ts {
 
     export interface Declaration extends Node {
         _declarationBrand: any;
+    }
+
+    export interface NamedDeclaration extends Declaration {
         name?: DeclarationName;
     }
 
-    export interface DeclarationStatement extends Declaration, Statement {
+    export interface DeclarationStatement extends NamedDeclaration, Statement {
         name?: Identifier | StringLiteral | NumericLiteral;
     }
 
@@ -622,7 +631,7 @@ namespace ts {
         expression: LeftHandSideExpression;
     }
 
-    export interface TypeParameterDeclaration extends Declaration {
+    export interface TypeParameterDeclaration extends NamedDeclaration {
         kind: SyntaxKind.TypeParameter;
         parent?: DeclarationWithTypeParameters;
         name: Identifier;
@@ -633,7 +642,7 @@ namespace ts {
         expression?: Expression;
     }
 
-    export interface SignatureDeclaration extends Declaration {
+    export interface SignatureDeclaration extends NamedDeclaration {
         name?: PropertyName;
         typeParameters?: NodeArray<TypeParameterDeclaration>;
         parameters: NodeArray<ParameterDeclaration>;
@@ -650,7 +659,7 @@ namespace ts {
 
     export type BindingName = Identifier | BindingPattern;
 
-    export interface VariableDeclaration extends Declaration {
+    export interface VariableDeclaration extends NamedDeclaration {
         kind: SyntaxKind.VariableDeclaration;
         parent?: VariableDeclarationList | CatchClause;
         name: BindingName;                  // Declared variable name
@@ -664,7 +673,7 @@ namespace ts {
         declarations: NodeArray<VariableDeclaration>;
     }
 
-    export interface ParameterDeclaration extends Declaration {
+    export interface ParameterDeclaration extends NamedDeclaration {
         kind: SyntaxKind.Parameter;
         parent?: SignatureDeclaration;
         dotDotDotToken?: DotDotDotToken;    // Present on rest parameter
@@ -674,7 +683,7 @@ namespace ts {
         initializer?: Expression;           // Optional initializer
     }
 
-    export interface BindingElement extends Declaration {
+    export interface BindingElement extends NamedDeclaration {
         kind: SyntaxKind.BindingElement;
         parent?: BindingPattern;
         propertyName?: PropertyName;        // Binding property name (in object binding pattern)
@@ -699,7 +708,7 @@ namespace ts {
         initializer?: Expression;           // Optional initializer
     }
 
-    export interface ObjectLiteralElement extends Declaration {
+    export interface ObjectLiteralElement extends NamedDeclaration {
         _objectLiteralBrandBrand: any;
         name?: PropertyName;
     }
@@ -743,7 +752,7 @@ namespace ts {
     // SyntaxKind.ShorthandPropertyAssignment
     // SyntaxKind.EnumMember
     // SyntaxKind.JSDocPropertyTag
-    export interface VariableLikeDeclaration extends Declaration {
+    export interface VariableLikeDeclaration extends NamedDeclaration {
         propertyName?: PropertyName;
         dotDotDotToken?: DotDotDotToken;
         name: DeclarationName;
@@ -752,7 +761,7 @@ namespace ts {
         initializer?: Expression;
     }
 
-    export interface PropertyLikeDeclaration extends Declaration {
+    export interface PropertyLikeDeclaration extends NamedDeclaration {
         name: PropertyName;
     }
 
@@ -1216,8 +1225,7 @@ namespace ts {
 
     export type BinaryOperatorToken = Token<BinaryOperator>;
 
-    // Binary expressions can be declarations if they are 'exports.foo = bar' expressions in JS files
-    export interface BinaryExpression extends Expression, Declaration {
+    export interface BinaryExpression extends Expression, Declaration  {
         kind: SyntaxKind.BinaryExpression;
         left: Expression;
         operatorToken: BinaryOperatorToken;
@@ -1417,7 +1425,7 @@ namespace ts {
     export type EntityNameExpression = Identifier | PropertyAccessEntityNameExpression | ParenthesizedExpression;
     export type EntityNameOrEntityNameExpression = EntityName | EntityNameExpression;
 
-    export interface PropertyAccessExpression extends MemberExpression, Declaration {
+    export interface PropertyAccessExpression extends MemberExpression, NamedDeclaration {
         kind: SyntaxKind.PropertyAccessExpression;
         expression: LeftHandSideExpression;
         name: Identifier;
@@ -1506,7 +1514,7 @@ namespace ts {
     //       for the same reasons we treat NewExpression as a PrimaryExpression.
     export interface MetaProperty extends PrimaryExpression {
         kind: SyntaxKind.MetaProperty;
-        keywordToken: SyntaxKind;
+        keywordToken: SyntaxKind.NewKeyword;
         name: Identifier;
     }
 
@@ -1597,6 +1605,14 @@ namespace ts {
         kind: SyntaxKind.EndOfDeclarationMarker;
     }
 
+    /**
+     * A list of comma-seperated expressions. This node is only created by transformations.
+     */
+    export interface CommaListExpression extends Expression {
+        kind: SyntaxKind.CommaListExpression;
+        elements: NodeArray<Expression>;
+    }
+
     /**
      * Marks the beginning of a merged transformed declaration.
      */
@@ -1762,7 +1778,7 @@ namespace ts {
 
     export type DeclarationWithTypeParameters = SignatureDeclaration | ClassLikeDeclaration | InterfaceDeclaration | TypeAliasDeclaration;
 
-    export interface ClassLikeDeclaration extends Declaration {
+    export interface ClassLikeDeclaration extends NamedDeclaration {
         name?: Identifier;
         typeParameters?: NodeArray<TypeParameterDeclaration>;
         heritageClauses?: NodeArray<HeritageClause>;
@@ -1778,12 +1794,12 @@ namespace ts {
         kind: SyntaxKind.ClassExpression;
     }
 
-    export interface ClassElement extends Declaration {
+    export interface ClassElement extends NamedDeclaration {
         _classElementBrand: any;
         name?: PropertyName;
     }
 
-    export interface TypeElement extends Declaration {
+    export interface TypeElement extends NamedDeclaration {
         _typeElementBrand: any;
         name?: PropertyName;
         questionToken?: QuestionToken;
@@ -1811,7 +1827,7 @@ namespace ts {
         type: TypeNode;
     }
 
-    export interface EnumMember extends Declaration {
+    export interface EnumMember extends NamedDeclaration {
         kind: SyntaxKind.EnumMember;
         parent?: EnumDeclaration;
         // This does include ComputedPropertyName, but the parser will give an error
@@ -1900,14 +1916,14 @@ namespace ts {
     // import d, * as ns from "mod" => name = d, namedBinding: NamespaceImport = { name: ns }
     // import { a, b as x } from "mod" => name = undefined, namedBinding: NamedImports = { elements: [{ name: a }, { name: x, propertyName: b}]}
     // import d, { a, b as x } from "mod" => name = d, namedBinding: NamedImports = { elements: [{ name: a }, { name: x, propertyName: b}]}
-    export interface ImportClause extends Declaration {
+    export interface ImportClause extends NamedDeclaration {
         kind: SyntaxKind.ImportClause;
         parent?: ImportDeclaration;
         name?: Identifier; // Default binding
         namedBindings?: NamedImportBindings;
     }
 
-    export interface NamespaceImport extends Declaration {
+    export interface NamespaceImport extends NamedDeclaration {
         kind: SyntaxKind.NamespaceImport;
         parent?: ImportClause;
         name: Identifier;
@@ -1940,14 +1956,14 @@ namespace ts {
 
     export type NamedImportsOrExports = NamedImports | NamedExports;
 
-    export interface ImportSpecifier extends Declaration {
+    export interface ImportSpecifier extends NamedDeclaration {
         kind: SyntaxKind.ImportSpecifier;
         parent?: NamedImports;
         propertyName?: Identifier;  // Name preceding "as" keyword (or undefined when "as" is absent)
         name: Identifier;           // Declared name
     }
 
-    export interface ExportSpecifier extends Declaration {
+    export interface ExportSpecifier extends NamedDeclaration {
         kind: SyntaxKind.ExportSpecifier;
         parent?: NamedExports;
         propertyName?: Identifier;  // Name preceding "as" keyword (or undefined when "as" is absent)
@@ -2113,7 +2129,7 @@ namespace ts {
         typeExpression: JSDocTypeExpression;
     }
 
-    export interface JSDocTypedefTag extends JSDocTag, Declaration {
+    export interface JSDocTypedefTag extends JSDocTag, NamedDeclaration {
         kind: SyntaxKind.JSDocTypedefTag;
         fullName?: JSDocNamespaceDeclaration | Identifier;
         name?: Identifier;
@@ -2408,7 +2424,14 @@ namespace ts {
         /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective>;
         /* @internal */ isSourceFileFromExternalLibrary(file: SourceFile): boolean;
         // For testing purposes only.
-        /* @internal */ structureIsReused?: boolean;
+        /* @internal */ structureIsReused?: StructureIsReused;
+    }
+
+    /* @internal */
+    export const enum StructureIsReused {
+        Not         = 0,
+        SafeModules = 1 << 0,
+        Completely  = 1 << 1,
     }
 
     export interface CustomTransformers {
@@ -2505,11 +2528,11 @@ namespace ts {
         indexInfoToIndexSignatureDeclaration(indexInfo: IndexInfo, kind: IndexKind, enclosingDeclaration?: Node, flags?: NodeBuilderFlags): IndexSignatureDeclaration;
 
         getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[];
-        getSymbolAtLocation(node: Node): Symbol;
+        getSymbolAtLocation(node: Node): Symbol | undefined;
         getSymbolsOfParameterPropertyDeclaration(parameter: ParameterDeclaration, parameterName: string): Symbol[];
-        getShorthandAssignmentValueSymbol(location: Node): Symbol;
-        getExportSpecifierLocalTargetSymbol(location: ExportSpecifier): Symbol;
-        getPropertySymbolOfDestructuringAssignment(location: Identifier): Symbol;
+        getShorthandAssignmentValueSymbol(location: Node): Symbol | undefined;
+        getExportSpecifierLocalTargetSymbol(location: ExportSpecifier): Symbol | undefined;
+        getPropertySymbolOfDestructuringAssignment(location: Identifier): Symbol | undefined;
         getTypeAtLocation(node: Node): Type;
         getTypeFromTypeNode(node: TypeNode): Type;
         signatureToString(signature: Signature, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): string;
@@ -2519,16 +2542,16 @@ namespace ts {
         getFullyQualifiedName(symbol: Symbol): string;
         getAugmentedPropertiesOfType(type: Type): Symbol[];
         getRootSymbols(symbol: Symbol): Symbol[];
-        getContextualType(node: Expression): Type;
-        getResolvedSignature(node: CallLikeExpression, candidatesOutArray?: Signature[]): Signature;
-        getSignatureFromDeclaration(declaration: SignatureDeclaration): Signature;
-        isImplementationOfOverload(node: FunctionLikeDeclaration): boolean;
+        getContextualType(node: Expression): Type | undefined;
+        getResolvedSignature(node: CallLikeExpression, candidatesOutArray?: Signature[]): Signature | undefined;
+        getSignatureFromDeclaration(declaration: SignatureDeclaration): Signature | undefined;
+        isImplementationOfOverload(node: FunctionLikeDeclaration): boolean | undefined;
         isUndefinedSymbol(symbol: Symbol): boolean;
         isArgumentsSymbol(symbol: Symbol): boolean;
         isUnknownSymbol(symbol: Symbol): boolean;
         /* @internal */ getMergedSymbol(symbol: Symbol): Symbol;
 
-        getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): string | number;
+        getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): string | number | undefined;
         isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName, propertyName: string): boolean;
         /** Follow all aliases to get the original symbol. */
         getAliasedSymbol(symbol: Symbol): Symbol;
@@ -2538,15 +2561,18 @@ namespace ts {
         /** Unlike `getExportsOfModule`, this includes properties of an `export =` value. */
         /* @internal */ getExportsAndPropertiesOfModule(moduleSymbol: Symbol): Symbol[];
 
-        getAllAttributesTypeFromJsxOpeningLikeElement(elementNode: JsxOpeningLikeElement): Type;
+        getAllAttributesTypeFromJsxOpeningLikeElement(elementNode: JsxOpeningLikeElement): Type | undefined;
         getJsxIntrinsicTagNames(): Symbol[];
         isOptionalParameter(node: ParameterDeclaration): boolean;
         getAmbientModules(): Symbol[];
 
         tryGetMemberInModuleExports(memberName: string, moduleSymbol: Symbol): Symbol | undefined;
         getApparentType(type: Type): Type;
+        getSuggestionForNonexistentProperty(node: Identifier, containingType: Type): string | undefined;
+        getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string | undefined;
+        /* @internal */ getBaseConstraintOfType(type: Type): Type | undefined;
 
-        /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol;
+        /* @internal */ tryFindAmbientModuleWithoutAugmentations(moduleName: string): Symbol | undefined;
 
         // Should not be called directly.  Should only be accessed through the Program instance.
         /* @internal */ getDiagnostics(sourceFile?: SourceFile, cancellationToken?: CancellationToken): Diagnostic[];
@@ -2557,22 +2583,42 @@ namespace ts {
         /* @internal */ getIdentifierCount(): number;
         /* @internal */ getSymbolCount(): number;
         /* @internal */ getTypeCount(): number;
+
+        /**
+         * For a union, will include a property if it's defined in *any* of the member types.
+         * So for `{ a } | { b }`, this will include both `a` and `b`.
+         */
+        /* @internal */ getAllPossiblePropertiesOfType(type: Type): Symbol[];
     }
 
     export enum NodeBuilderFlags {
         None                                    = 0,
-        allowThisInObjectLiteral                = 1 << 0,
-        allowQualifedNameInPlaceOfIdentifier    = 1 << 1,
-        allowTypeParameterInQualifiedName       = 1 << 2,
-        allowAnonymousIdentifier                = 1 << 3,
-        allowEmptyUnionOrIntersection           = 1 << 4,
-        allowEmptyTuple                         = 1 << 5
+        // Options
+        NoTruncation                            = 1 << 0,   // Don't truncate result
+        WriteArrayAsGenericType                 = 1 << 1,   // Write Array<T> instead T[]
+        WriteTypeArgumentsOfSignature           = 1 << 5,   // Write the type arguments instead of type parameters of the signature
+        UseFullyQualifiedType                   = 1 << 6,   // Write out the fully qualified type name (eg. Module.Type, instead of Type)
+        SuppressAnyReturnType                   = 1 << 8,   // If the return type is any-like, don't offer a return type.
+        WriteTypeParametersInQualifiedName      = 1 << 9,
+
+        // Error handling
+        AllowThisInObjectLiteral                = 1 << 10,
+        AllowQualifedNameInPlaceOfIdentifier    = 1 << 11,
+        AllowAnonymousIdentifier                = 1 << 13,
+        AllowEmptyUnionOrIntersection           = 1 << 14,
+        AllowEmptyTuple                         = 1 << 15,
+
+        IgnoreErrors = AllowThisInObjectLiteral | AllowQualifedNameInPlaceOfIdentifier | AllowAnonymousIdentifier | AllowEmptyUnionOrIntersection | AllowEmptyTuple,
+
+        // State
+        InObjectTypeLiteral                     = 1 << 20,
+        InTypeAlias                             = 1 << 23,    // Writing type in type alias declaration
     }
 
     export interface SymbolDisplayBuilder {
         buildTypeDisplay(type: Type, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildSymbolDisplay(symbol: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, meaning?: SymbolFlags, flags?: SymbolFormatFlags): void;
-        buildSignatureDisplay(signatures: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): void;
+        buildSignatureDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): void;
         buildIndexSignatureDisplay(info: IndexInfo, writer: SymbolWriter, kind: IndexKind, enclosingDeclaration?: Node, globalFlags?: TypeFormatFlags, symbolStack?: Symbol[]): void;
         buildParameterDisplay(parameter: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildTypeParameterDisplay(tp: TypeParameter, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
@@ -2722,12 +2768,11 @@ namespace ts {
         getNodeCheckFlags(node: Node): NodeCheckFlags;
         isDeclarationVisible(node: Declaration): boolean;
         collectLinkedAliases(node: Identifier): Node[];
-        isImplementationOfOverload(node: FunctionLikeDeclaration): boolean;
+        isImplementationOfOverload(node: FunctionLikeDeclaration): boolean | undefined;
         isRequiredInitializedParameter(node: ParameterDeclaration): boolean;
         writeTypeOfDeclaration(declaration: AccessorDeclaration | VariableLikeDeclaration, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
         writeReturnTypeOfSignatureDeclaration(signatureDeclaration: SignatureDeclaration, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
         writeTypeOfExpression(expr: Expression, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
-        writeBaseConstructorTypeOfClass(node: ClassLikeDeclaration, enclosingDeclaration: Node, flags: TypeFormatFlags, writer: SymbolWriter): void;
         isSymbolAccessible(symbol: Symbol, enclosingDeclaration: Node, meaning: SymbolFlags, shouldComputeAliasToMarkVisible: boolean): SymbolAccessibilityResult;
         isEntityNameVisible(entityName: EntityNameOrEntityNameExpression, enclosingDeclaration: Node): SymbolVisibilityResult;
         // Returns the constant value this property access resolves to, or 'undefined' for a non-constant
@@ -3114,7 +3159,7 @@ namespace ts {
      */
     export interface TypeReference extends ObjectType {
         target: GenericType;    // Type reference target
-        typeArguments: Type[];  // Type reference type arguments (undefined if none)
+        typeArguments?: Type[];  // Type reference type arguments (undefined if none)
     }
 
     // Generic class and interface types
@@ -3244,7 +3289,7 @@ namespace ts {
 
     export interface Signature {
         declaration: SignatureDeclaration;  // Originating declaration
-        typeParameters: TypeParameter[];    // Type parameters (undefined if non-generic)
+        typeParameters?: TypeParameter[];    // Type parameters (undefined if non-generic)
         parameters: Symbol[];               // Parameters
         /* @internal */
         thisParameter?: Symbol;             // symbol of this-type parameter
@@ -3355,9 +3400,9 @@ namespace ts {
     }
 
     export interface Diagnostic {
-        file: SourceFile;
-        start: number;
-        length: number;
+        file: SourceFile | undefined;
+        start: number | undefined;
+        length: number | undefined;
         messageText: string | DiagnosticMessageChain;
         category: DiagnosticCategory;
         code: number;
@@ -3506,7 +3551,7 @@ namespace ts {
 
     export const enum NewLineKind {
         CarriageReturnLineFeed = 0,
-        LineFeed = 1,
+        LineFeed = 1
     }
 
     export interface LineAndCharacter {
@@ -3949,14 +3994,16 @@ namespace ts {
         HelperName = 1 << 12,
         ExportName = 1 << 13,                    // Ensure an export prefix is added for an identifier that points to an exported declaration with a local name (see SymbolFlags.ExportHasLocal).
         LocalName = 1 << 14,                     // Ensure an export prefix is not added for an identifier that points to an exported declaration.
-        Indented = 1 << 15,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
-        NoIndentation = 1 << 16,                 // Do not indent the node.
-        AsyncFunctionBody = 1 << 17,
-        ReuseTempVariableScope = 1 << 18,        // Reuse the existing temp variable scope during emit.
-        CustomPrologue = 1 << 19,                // Treat the statement as if it were a prologue directive (NOTE: Prologue directives are *not* transformed).
-        NoHoisting = 1 << 20,                    // Do not hoist this declaration in --module system
-        HasEndOfDeclarationMarker = 1 << 21,     // Declaration has an associated NotEmittedStatement to mark the end of the declaration
-        Iterator = 1 << 22,                      // The expression to a `yield*` should be treated as an Iterator when down-leveling, not an Iterable.
+        InternalName = 1 << 15,                  // The name is internal to an ES5 class body function.
+        Indented = 1 << 16,                      // Adds an explicit extra indentation level for class and function bodies when printing (used to match old emitter).
+        NoIndentation = 1 << 17,                 // Do not indent the node.
+        AsyncFunctionBody = 1 << 18,
+        ReuseTempVariableScope = 1 << 19,        // Reuse the existing temp variable scope during emit.
+        CustomPrologue = 1 << 20,                // Treat the statement as if it were a prologue directive (NOTE: Prologue directives are *not* transformed).
+        NoHoisting = 1 << 21,                    // Do not hoist this declaration in --module system
+        HasEndOfDeclarationMarker = 1 << 22,     // Declaration has an associated NotEmittedStatement to mark the end of the declaration
+        Iterator = 1 << 23,                      // The expression to a `yield*` should be treated as an Iterator when down-leveling, not an Iterable.
+        NoAsciiEscaping = 1 << 24,               // When synthesizing nodes that lack an original node or textSourceNode, we want to write the text on the node with ASCII escaping substitutions.
     }
 
     export interface EmitHelper {
@@ -3981,11 +4028,12 @@ namespace ts {
         Awaiter = 1 << 6,           // __awaiter (used by ES2017 async functions transformation)
         Generator = 1 << 7,         // __generator (used by ES2015 generator transformation)
         Values = 1 << 8,            // __values (used by ES2015 for..of and yield* transformations)
-        Read = 1 << 9,             // __read (used by ES2015 iterator destructuring transformation)
+        Read = 1 << 9,              // __read (used by ES2015 iterator destructuring transformation)
         Spread = 1 << 10,           // __spread (used by ES2015 array spread and argument list spread transformations)
-        AsyncGenerator = 1 << 11,   // __asyncGenerator (used by ES2017 async generator transformation)
-        AsyncDelegator = 1 << 12,   // __asyncDelegator (used by ES2017 async generator yield* transformation)
-        AsyncValues = 1 << 13,      // __asyncValues (used by ES2017 for..await..of transformation)
+        Await = 1 << 11,            // __await (used by ES2017 async generator transformation)
+        AsyncGenerator = 1 << 12,   // __asyncGenerator (used by ES2017 async generator transformation)
+        AsyncDelegator = 1 << 13,   // __asyncDelegator (used by ES2017 async generator yield* transformation)
+        AsyncValues = 1 << 14,      // __asyncValues (used by ES2017 for..await..of transformation)
 
         // Helpers included by ES2015 for..of
         ForOfIncludes = Values,
@@ -3993,6 +4041,12 @@ namespace ts {
         // Helpers included by ES2017 for..await..of
         ForAwaitOfIncludes = AsyncValues,
 
+        // Helpers included by ES2017 async generators
+        AsyncGeneratorIncludes = Await | AsyncGenerator,
+
+        // Helpers included by yield* in ES2017 async generators
+        AsyncDelegatorIncludes = Await | AsyncDelegator | AsyncValues,
+
         // Helpers included by ES2015 spread
         SpreadIncludes = Read | Spread,
 
@@ -4162,7 +4216,7 @@ namespace ts {
          * Prints a bundle of source files as-is, without any emit transformations.
          */
         printBundle(bundle: Bundle): string;
-        /*@internal*/ writeNode(hint: EmitHint, node: Node, sourceFile: SourceFile, writer: EmitTextWriter): void;
+        /*@internal*/ writeNode(hint: EmitHint, node: Node, sourceFile: SourceFile | undefined, writer: EmitTextWriter): void;
         /*@internal*/ writeFile(sourceFile: SourceFile, writer: EmitTextWriter): void;
         /*@internal*/ writeBundle(bundle: Bundle, writer: EmitTextWriter): void;
     }

src/compiler/utilities.ts

@@ -11,12 +11,12 @@ namespace ts {
         isTypeReferenceDirective?: boolean;
     }
 
-    export function getDeclarationOfKind(symbol: Symbol, kind: SyntaxKind): Declaration {
+    export function getDeclarationOfKind<T extends Declaration>(symbol: Symbol, kind: T["kind"]): T {
         const declarations = symbol.declarations;
         if (declarations) {
             for (const declaration of declarations) {
                 if (declaration.kind === kind) {
-                    return declaration;
+                    return declaration as T;
                 }
             }
         }
@@ -122,9 +122,8 @@ namespace ts {
 
     /* @internal */
     export function hasChangesInResolutions<T>(names: string[], newResolutions: T[], oldResolutions: Map<T>, comparer: (oldResolution: T, newResolution: T) => boolean): boolean {
-        if (names.length !== newResolutions.length) {
-            return false;
-        }
+        Debug.assert(names.length === newResolutions.length);
+
         for (let i = 0; i < names.length; i++) {
             const newResolution = newResolutions[i];
             const oldResolution = oldResolutions && oldResolutions.get(names[i]);
@@ -329,19 +328,21 @@ namespace ts {
             return getSourceTextOfNodeFromSourceFile(sourceFile, node);
         }
 
+        const escapeText = getEmitFlags(node) & EmitFlags.NoAsciiEscaping ? escapeString : escapeNonAsciiString;
+
         // If we can't reach the original source text, use the canonical form if it's a number,
-        // or an escaped quoted form of the original text if it's string-like.
+        // or a (possibly escaped) quoted form of the original text if it's string-like.
         switch (node.kind) {
             case SyntaxKind.StringLiteral:
-                return getQuotedEscapedLiteralText('"', node.text, '"');
+                return '"' + escapeText(node.text) + '"';
             case SyntaxKind.NoSubstitutionTemplateLiteral:
-                return getQuotedEscapedLiteralText("`", node.text, "`");
+                return "`" + escapeText(node.text) + "`";
             case SyntaxKind.TemplateHead:
-                return getQuotedEscapedLiteralText("`", node.text, "${");
+                return "`" + escapeText(node.text) + "${";
             case SyntaxKind.TemplateMiddle:
-                return getQuotedEscapedLiteralText("}", node.text, "${");
+                return "}" + escapeText(node.text) + "${";
             case SyntaxKind.TemplateTail:
-                return getQuotedEscapedLiteralText("}", node.text, "`");
+                return "}" + escapeText(node.text) + "`";
             case SyntaxKind.NumericLiteral:
                 return node.text;
         }
@@ -350,11 +351,7 @@ namespace ts {
     }
 
     export function getTextOfConstantValue(value: string | number) {
-        return typeof value === "string" ? getQuotedEscapedLiteralText('"', value, '"') : "" + value;
-    }
-
-    function getQuotedEscapedLiteralText(leftQuote: string, text: string, rightQuote: string) {
-        return leftQuote + escapeNonAsciiCharacters(escapeString(text)) + rightQuote;
+        return typeof value === "string" ? '"' + escapeNonAsciiString(value) + '"' : "" + value;
     }
 
     // Add an extra underscore to identifiers that start with two underscores to avoid issues with magic names like '__proto__'
@@ -470,7 +467,7 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
-    export function getNameFromIndexInfo(info: IndexInfo) {
+    export function getNameFromIndexInfo(info: IndexInfo): string | undefined {
         return info.declaration ? declarationNameToString(info.declaration.parameters[0].name) : undefined;
     }
 
@@ -571,7 +568,7 @@ namespace ts {
             case SyntaxKind.GetAccessor:
             case SyntaxKind.SetAccessor:
             case SyntaxKind.TypeAliasDeclaration:
-                errorNode = (<Declaration>node).name;
+                errorNode = (<NamedDeclaration>node).name;
                 break;
             case SyntaxKind.ArrowFunction:
                 return getErrorSpanForArrowFunction(sourceFile, <ArrowFunction>node);
@@ -594,10 +591,6 @@ namespace ts {
         return (file.externalModuleIndicator || file.commonJsModuleIndicator) !== undefined;
     }
 
-    export function isDeclarationFile(file: SourceFile): boolean {
-        return file.isDeclarationFile;
-    }
-
     export function isConstEnumDeclaration(node: Node): boolean {
         return node.kind === SyntaxKind.EnumDeclaration && isConst(node);
     }
@@ -886,6 +879,16 @@ namespace ts {
         return false;
     }
 
+    export function isFunctionOrConstructorTypeNode(node: Node): node is FunctionTypeNode | ConstructorTypeNode {
+        switch (node.kind) {
+            case SyntaxKind.FunctionType:
+            case SyntaxKind.ConstructorType:
+                return true;
+        }
+
+        return false;
+    }
+
     export function introducesArgumentsExoticObject(node: Node) {
         switch (node.kind) {
             case SyntaxKind.MethodDeclaration:
@@ -1147,6 +1150,10 @@ namespace ts {
         }
     }
 
+    export function isCallOrNewExpression(node: Node): node is CallExpression | NewExpression {
+        return node.kind === SyntaxKind.CallExpression || node.kind === SyntaxKind.NewExpression;
+    }
+
     export function getInvokedExpression(node: CallLikeExpression): Expression {
         if (node.kind === SyntaxKind.TaggedTemplateExpression) {
             return (<TaggedTemplateExpression>node).tag;
@@ -1759,22 +1766,44 @@ namespace ts {
 
     // True if the given identifier, string literal, or number literal is the name of a declaration node
     export function isDeclarationName(name: Node): boolean {
-        if (name.kind !== SyntaxKind.Identifier && name.kind !== SyntaxKind.StringLiteral && name.kind !== SyntaxKind.NumericLiteral) {
-            return false;
+        switch (name.kind) {
+            case SyntaxKind.Identifier:
+            case SyntaxKind.StringLiteral:
+            case SyntaxKind.NumericLiteral:
+                return isDeclaration(name.parent) && name.parent.name === name;
+            default:
+                return false;
         }
+    }
 
-        const parent = name.parent;
-        if (parent.kind === SyntaxKind.ImportSpecifier || parent.kind === SyntaxKind.ExportSpecifier) {
-            if ((<ImportOrExportSpecifier>parent).propertyName) {
-                return true;
+    export function getNameOfDeclaration(declaration: Declaration): DeclarationName {
+        if (!declaration) {
+            return undefined;
+        }
+        if (declaration.kind === SyntaxKind.BinaryExpression) {
+            const kind = getSpecialPropertyAssignmentKind(declaration as BinaryExpression);
+            const lhs = (declaration as BinaryExpression).left;
+            switch (kind) {
+                case SpecialPropertyAssignmentKind.None:
+                case SpecialPropertyAssignmentKind.ModuleExports:
+                    return undefined;
+                case SpecialPropertyAssignmentKind.ExportsProperty:
+                    if (lhs.kind === SyntaxKind.Identifier) {
+                        return (lhs as PropertyAccessExpression).name;
+                    }
+                    else {
+                        return ((lhs as PropertyAccessExpression).expression as PropertyAccessExpression).name;
+                    }
+                case SpecialPropertyAssignmentKind.ThisProperty:
+                case SpecialPropertyAssignmentKind.Property:
+                    return (lhs as PropertyAccessExpression).name;
+                case SpecialPropertyAssignmentKind.PrototypeProperty:
+                    return ((lhs as PropertyAccessExpression).expression as PropertyAccessExpression).name;
             }
         }
-
-        if (isDeclaration(parent)) {
-            return (<Declaration>parent).name === name;
+        else {
+            return (declaration as NamedDeclaration).name;
         }
-
-        return false;
     }
 
     export function isLiteralComputedPropertyDeclarationName(node: Node) {
@@ -1797,7 +1826,7 @@ namespace ts {
             case SyntaxKind.PropertyAssignment:
             case SyntaxKind.PropertyAccessExpression:
                 // Name in member declaration or property name in property access
-                return (<Declaration | PropertyAccessExpression>parent).name === node;
+                return (<NamedDeclaration | PropertyAccessExpression>parent).name === node;
             case SyntaxKind.QualifiedName:
                 // Name on right hand side of dot in a type query
                 if ((<QualifiedName>parent).right === node) {
@@ -1929,16 +1958,18 @@ namespace ts {
     }
 
     export const enum FunctionFlags {
-        Normal = 0,
-        Generator = 1 << 0,
-        Async = 1 << 1,
-        AsyncOrAsyncGenerator = Async | Generator,
-        Invalid = 1 << 2,
-        InvalidAsyncOrAsyncGenerator = AsyncOrAsyncGenerator | Invalid,
-        InvalidGenerator = Generator | Invalid,
+        Normal = 0,             // Function is a normal function
+        Generator = 1 << 0,     // Function is a generator function or async generator function
+        Async = 1 << 1,         // Function is an async function or an async generator function
+        Invalid = 1 << 2,       // Function is a signature or overload and does not have a body.
+        AsyncGenerator = Async | Generator, // Function is an async generator function
     }
 
-    export function getFunctionFlags(node: FunctionLikeDeclaration) {
+    export function getFunctionFlags(node: FunctionLikeDeclaration | undefined) {
+        if (!node) {
+            return FunctionFlags.Invalid;
+        }
+
         let flags = FunctionFlags.Normal;
         switch (node.kind) {
             case SyntaxKind.FunctionDeclaration:
@@ -1993,7 +2024,8 @@ namespace ts {
      *      Symbol.
      */
     export function hasDynamicName(declaration: Declaration): boolean {
-        return declaration.name && isDynamicName(declaration.name);
+        const name = getNameOfDeclaration(declaration);
+        return name && isDynamicName(name);
     }
 
     export function isDynamicName(name: DeclarationName): boolean {
@@ -2303,6 +2335,9 @@ namespace ts {
             case SyntaxKind.SpreadElement:
                 return 1;
 
+            case SyntaxKind.CommaListExpression:
+                return 0;
+
             default:
                 return -1;
         }
@@ -2435,7 +2470,8 @@ namespace ts {
     }
 
     const nonAsciiCharacters = /[^\u0000-\u007F]/g;
-    export function escapeNonAsciiCharacters(s: string): string {
+    export function escapeNonAsciiString(s: string): string {
+        s = escapeString(s);
         // Replace non-ASCII characters with '\uNNNN' escapes if any exist.
         // Otherwise just return the original string.
         return nonAsciiCharacters.test(s) ?
@@ -2539,7 +2575,7 @@ namespace ts {
 
     export function getExternalModuleNameFromDeclaration(host: EmitHost, resolver: EmitResolver, declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration | ModuleDeclaration): string {
         const file = resolver.getExternalModuleFileFromDeclaration(declaration);
-        if (!file || isDeclarationFile(file)) {
+        if (!file || file.isDeclarationFile) {
             return undefined;
         }
         return getResolvedExternalModuleName(host, file);
@@ -2612,7 +2648,7 @@ namespace ts {
 
     /** Don't call this for `--outFile`, just for `--outDir` or plain emit. `--outFile` needs additional checks. */
     export function sourceFileMayBeEmitted(sourceFile: SourceFile, options: CompilerOptions, isSourceFileFromExternalLibrary: (file: SourceFile) => boolean) {
-        return !(options.noEmitForJsFiles && isSourceFileJavaScript(sourceFile)) && !isDeclarationFile(sourceFile) && !isSourceFileFromExternalLibrary(sourceFile);
+        return !(options.noEmitForJsFiles && isSourceFileJavaScript(sourceFile)) && !sourceFile.isDeclarationFile && !isSourceFileFromExternalLibrary(sourceFile);
     }
 
     /**
@@ -2758,7 +2794,7 @@ namespace ts {
             forEach(declarations, (member: Declaration) => {
                 if ((member.kind === SyntaxKind.GetAccessor || member.kind === SyntaxKind.SetAccessor)
                     && hasModifier(member, ModifierFlags.Static) === hasModifier(accessor, ModifierFlags.Static)) {
-                    const memberName = getPropertyNameForPropertyNameNode(member.name);
+                    const memberName = getPropertyNameForPropertyNameNode((member as NamedDeclaration).name);
                     const accessorName = getPropertyNameForPropertyNameNode(accessor.name);
                     if (memberName === accessorName) {
                         if (!firstAccessor) {
@@ -3228,13 +3264,13 @@ namespace ts {
     const carriageReturnLineFeed = "\r\n";
     const lineFeed = "\n";
     export function getNewLineCharacter(options: CompilerOptions | PrinterOptions): string {
-        if (options.newLine === NewLineKind.CarriageReturnLineFeed) {
-            return carriageReturnLineFeed;
+        switch (options.newLine) {
+            case NewLineKind.CarriageReturnLineFeed:
+                return carriageReturnLineFeed;
+            case NewLineKind.LineFeed:
+                return lineFeed;
         }
-        else if (options.newLine === NewLineKind.LineFeed) {
-            return lineFeed;
-        }
-        else if (sys) {
+        if (sys) {
             return sys.newLine;
         }
         return carriageReturnLineFeed;
@@ -3573,10 +3609,6 @@ namespace ts {
         return node.kind === SyntaxKind.Identifier;
     }
 
-    export function isVoidExpression(node: Node): node is VoidExpression {
-        return node.kind === SyntaxKind.VoidExpression;
-    }
-
     export function isGeneratedIdentifier(node: Node): node is GeneratedIdentifier {
         // Using `>` here catches both `GeneratedIdentifierKind.None` and `undefined`.
         return isIdentifier(node) && node.autoGenerateKind > GeneratedIdentifierKind.None;
@@ -3653,7 +3685,18 @@ namespace ts {
             || kind === SyntaxKind.GetAccessor
             || kind === SyntaxKind.SetAccessor
             || kind === SyntaxKind.IndexSignature
-            || kind === SyntaxKind.SemicolonClassElement;
+            || kind === SyntaxKind.SemicolonClassElement
+            || kind === SyntaxKind.MissingDeclaration;
+    }
+
+    export function isTypeElement(node: Node): node is TypeElement {
+        const kind = node.kind;
+        return kind === SyntaxKind.ConstructSignature
+            || kind === SyntaxKind.CallSignature
+            || kind === SyntaxKind.PropertySignature
+            || kind === SyntaxKind.MethodSignature
+            || kind === SyntaxKind.IndexSignature
+            || kind === SyntaxKind.MissingDeclaration;
     }
 
     export function isObjectLiteralElementLike(node: Node): node is ObjectLiteralElementLike {
@@ -3884,6 +3927,7 @@ namespace ts {
             || kind === SyntaxKind.SpreadElement
             || kind === SyntaxKind.AsExpression
             || kind === SyntaxKind.OmittedExpression
+            || kind === SyntaxKind.CommaListExpression
             || isUnaryExpressionKind(kind);
     }
 
@@ -3975,6 +4019,10 @@ namespace ts {
         return node.kind === SyntaxKind.ImportEqualsDeclaration;
     }
 
+    export function isImportDeclaration(node: Node): node is ImportDeclaration {
+        return node.kind === SyntaxKind.ImportDeclaration;
+    }
+
     export function isImportClause(node: Node): node is ImportClause {
         return node.kind === SyntaxKind.ImportClause;
     }
@@ -3997,6 +4045,10 @@ namespace ts {
         return node.kind === SyntaxKind.ExportSpecifier;
     }
 
+    export function isExportAssignment(node: Node): node is ExportAssignment {
+        return node.kind === SyntaxKind.ExportAssignment;
+    }
+
     export function isModuleOrEnumDeclaration(node: Node): node is ModuleDeclaration | EnumDeclaration {
         return node.kind === SyntaxKind.ModuleDeclaration || node.kind === SyntaxKind.EnumDeclaration;
     }
@@ -4074,7 +4126,7 @@ namespace ts {
             || kind === SyntaxKind.MergeDeclarationMarker;
     }
 
-    export function isDeclaration(node: Node): node is Declaration {
+    export function isDeclaration(node: Node): node is NamedDeclaration {
         return isDeclarationKind(node.kind);
     }
 
@@ -4203,6 +4255,52 @@ namespace ts {
         // Firefox has Object.prototype.watch
         return options.watch && options.hasOwnProperty("watch");
     }
+
+    export function getCheckFlags(symbol: Symbol): CheckFlags {
+        return symbol.flags & SymbolFlags.Transient ? (<TransientSymbol>symbol).checkFlags : 0;
+    }
+
+    export function getDeclarationModifierFlagsFromSymbol(s: Symbol): ModifierFlags {
+        if (s.valueDeclaration) {
+            const flags = getCombinedModifierFlags(s.valueDeclaration);
+            return s.parent && s.parent.flags & SymbolFlags.Class ? flags : flags & ~ModifierFlags.AccessibilityModifier;
+        }
+        if (getCheckFlags(s) & CheckFlags.Synthetic) {
+            const checkFlags = (<TransientSymbol>s).checkFlags;
+            const accessModifier = checkFlags & CheckFlags.ContainsPrivate ? ModifierFlags.Private :
+                checkFlags & CheckFlags.ContainsPublic ? ModifierFlags.Public :
+                    ModifierFlags.Protected;
+            const staticModifier = checkFlags & CheckFlags.ContainsStatic ? ModifierFlags.Static : 0;
+            return accessModifier | staticModifier;
+        }
+        if (s.flags & SymbolFlags.Prototype) {
+            return ModifierFlags.Public | ModifierFlags.Static;
+        }
+        return 0;
+    }
+
+    export function levenshtein(s1: string, s2: string): number {
+        let previous: number[] = new Array(s2.length + 1);
+        let current: number[] = new Array(s2.length + 1);
+        for (let i = 0; i < s2.length + 1; i++) {
+            previous[i] = i;
+            current[i] = -1;
+        }
+        for (let i = 1; i < s1.length + 1; i++) {
+            current[0] = i;
+            for (let j = 1; j < s2.length + 1; j++) {
+                current[j] = Math.min(
+                    previous[j] + 1,
+                    current[j - 1] + 1,
+                    previous[j - 1] + (s1[i - 1] === s2[j - 1] ? 0 : 2));
+            }
+            // shift current back to previous, and then reuse previous' array
+            const tmp = previous;
+            previous = current;
+            current = tmp;
+        }
+        return previous[previous.length - 1];
+    }
 }
 
 namespace ts {

src/compiler/visitor.ts

@@ -218,17 +218,12 @@ namespace ts {
             return node;
         }
 
-        switch (node.kind) {
-            case SyntaxKind.SemicolonClassElement:
-            case SyntaxKind.EmptyStatement:
-            case SyntaxKind.OmittedExpression:
-            case SyntaxKind.DebuggerStatement:
-            case SyntaxKind.EndOfDeclarationMarker:
-            case SyntaxKind.MissingDeclaration:
-                // No need to visit nodes with no children.
-                return node;
-
+        switch (kind) {
             // Names
+
+            case SyntaxKind.Identifier:
+                return updateIdentifier(<Identifier>node, nodesVisitor((<Identifier>node).typeArguments, visitor, isTypeNode));
+
             case SyntaxKind.QualifiedName:
                 return updateQualifiedName(<QualifiedName>node,
                     visitNode((<QualifiedName>node).left, visitor, isEntityName),
@@ -238,45 +233,13 @@ namespace ts {
                 return updateComputedPropertyName(<ComputedPropertyName>node,
                     visitNode((<ComputedPropertyName>node).expression, visitor, isExpression));
 
-            // Signatures and Signature Elements
-            case SyntaxKind.FunctionType:
-                return updateFunctionTypeNode(<FunctionTypeNode>node,
-                    nodesVisitor((<FunctionTypeNode>node).typeParameters, visitor, isTypeParameter),
-                    visitParameterList((<FunctionTypeNode>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<FunctionTypeNode>node).type, visitor, isTypeNode));
+            // Signature elements
 
-            case SyntaxKind.ConstructorType:
-                return updateConstructorTypeNode(<ConstructorTypeNode>node,
-                    nodesVisitor((<ConstructorTypeNode>node).typeParameters, visitor, isTypeParameter),
-                    visitParameterList((<ConstructorTypeNode>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<ConstructorTypeNode>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.CallSignature:
-                return updateCallSignatureDeclaration(<CallSignatureDeclaration>node,
-                    nodesVisitor((<CallSignatureDeclaration>node).typeParameters, visitor, isTypeParameter),
-                    visitParameterList((<CallSignatureDeclaration>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<CallSignatureDeclaration>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.ConstructSignature:
-                return updateConstructSignatureDeclaration(<ConstructSignatureDeclaration>node,
-                    nodesVisitor((<ConstructSignatureDeclaration>node).typeParameters, visitor, isTypeParameter),
-                    visitParameterList((<ConstructSignatureDeclaration>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<ConstructSignatureDeclaration>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.MethodSignature:
-                return updateMethodSignature(<MethodSignature>node,
-                    nodesVisitor((<MethodSignature>node).typeParameters, visitor, isTypeParameter),
-                    visitParameterList((<MethodSignature>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<MethodSignature>node).type, visitor, isTypeNode),
-                    visitNode((<MethodSignature>node).name, visitor, isPropertyName),
-                    visitNode((<MethodSignature>node).questionToken, tokenVisitor, isToken));
-
-            case SyntaxKind.IndexSignature:
-                return updateIndexSignatureDeclaration(<IndexSignatureDeclaration>node,
-                    nodesVisitor((<IndexSignatureDeclaration>node).decorators, visitor, isDecorator),
-                    nodesVisitor((<IndexSignatureDeclaration>node).modifiers, visitor, isModifier),
-                    visitParameterList((<IndexSignatureDeclaration>node).parameters, visitor, context, nodesVisitor),
-                    visitNode((<IndexSignatureDeclaration>node).type, visitor, isTypeNode));
+            case SyntaxKind.TypeParameter:
+                return updateTypeParameterDeclaration(<TypeParameterDeclaration>node,
+                    visitNode((<TypeParameterDeclaration>node).name, visitor, isIdentifier),
+                    visitNode((<TypeParameterDeclaration>node).constraint, visitor, isTypeNode),
+                    visitNode((<TypeParameterDeclaration>node).default, visitor, isTypeNode));
 
             case SyntaxKind.Parameter:
                 return updateParameter(<ParameterDeclaration>node,
@@ -292,69 +255,11 @@ namespace ts {
                 return updateDecorator(<Decorator>node,
                     visitNode((<Decorator>node).expression, visitor, isExpression));
 
-            // Types
-
-            case SyntaxKind.TypeReference:
-                return updateTypeReferenceNode(<TypeReferenceNode>node,
-                    visitNode((<TypeReferenceNode>node).typeName, visitor, isEntityName),
-                    nodesVisitor((<TypeReferenceNode>node).typeArguments, visitor, isTypeNode));
-
-            case SyntaxKind.TypePredicate:
-                return updateTypePredicateNode(<TypePredicateNode>node,
-                    visitNode((<TypePredicateNode>node).parameterName, visitor),
-                    visitNode((<TypePredicateNode>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.TypeQuery:
-                return updateTypeQueryNode((<TypeQueryNode>node), visitNode((<TypeQueryNode>node).exprName, visitor, isEntityName));
-
-            case SyntaxKind.TypeLiteral:
-                return updateTypeLiteralNode((<TypeLiteralNode>node), nodesVisitor((<TypeLiteralNode>node).members, visitor));
-
-            case SyntaxKind.ArrayType:
-                return updateArrayTypeNode(<ArrayTypeNode>node, visitNode((<ArrayTypeNode>node).elementType, visitor, isTypeNode));
-
-            case SyntaxKind.TupleType:
-                return updateTypleTypeNode((<TupleTypeNode>node), nodesVisitor((<TupleTypeNode>node).elementTypes, visitor, isTypeNode));
-
-            case SyntaxKind.UnionType:
-            case SyntaxKind.IntersectionType:
-                return updateUnionOrIntersectionTypeNode(<UnionOrIntersectionTypeNode>node,
-                    nodesVisitor((<UnionOrIntersectionTypeNode>node).types, visitor, isTypeNode));
-
-            case SyntaxKind.ParenthesizedType:
-                throw Debug.fail("not implemented.");
-
-            case SyntaxKind.TypeOperator:
-                return updateTypeOperatorNode(<TypeOperatorNode>node, visitNode((<TypeOperatorNode>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.IndexedAccessType:
-                return updateIndexedAccessTypeNode((<IndexedAccessTypeNode>node),
-                    visitNode((<IndexedAccessTypeNode>node).objectType, visitor, isTypeNode),
-                    visitNode((<IndexedAccessTypeNode>node).indexType, visitor, isTypeNode));
-
-            case SyntaxKind.MappedType:
-                return updateMappedTypeNode((<MappedTypeNode>node),
-                    visitNode((<MappedTypeNode>node).readonlyToken, tokenVisitor, isToken),
-                    visitNode((<MappedTypeNode>node).typeParameter, visitor, isTypeParameter),
-                    visitNode((<MappedTypeNode>node).questionToken, tokenVisitor, isToken),
-                    visitNode((<MappedTypeNode>node).type, visitor, isTypeNode));
-
-            case SyntaxKind.LiteralType:
-                return updateLiteralTypeNode(<LiteralTypeNode>node,
-                    visitNode((<LiteralTypeNode>node).literal, visitor, isExpression));
-
-            // Type Declarations
-
-            case SyntaxKind.TypeParameter:
-                return updateTypeParameterDeclaration(<TypeParameterDeclaration>node,
-                    visitNode((<TypeParameterDeclaration>node).name, visitor, isIdentifier),
-                    visitNode((<TypeParameterDeclaration>node).constraint, visitor, isTypeNode),
-                    visitNode((<TypeParameterDeclaration>node).default, visitor, isTypeNode));
-
-            // Type members
+            // Type elements
 
             case SyntaxKind.PropertySignature:
                 return updatePropertySignature((<PropertySignature>node),
+                    nodesVisitor((<PropertySignature>node).modifiers, visitor, isToken),
                     visitNode((<PropertySignature>node).name, visitor, isPropertyName),
                     visitNode((<PropertySignature>node).questionToken, tokenVisitor, isToken),
                     visitNode((<PropertySignature>node).type, visitor, isTypeNode),
@@ -368,6 +273,14 @@ namespace ts {
                     visitNode((<PropertyDeclaration>node).type, visitor, isTypeNode),
                     visitNode((<PropertyDeclaration>node).initializer, visitor, isExpression));
 
+            case SyntaxKind.MethodSignature:
+                return updateMethodSignature(<MethodSignature>node,
+                    nodesVisitor((<MethodSignature>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<MethodSignature>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<MethodSignature>node).type, visitor, isTypeNode),
+                    visitNode((<MethodSignature>node).name, visitor, isPropertyName),
+                    visitNode((<MethodSignature>node).questionToken, tokenVisitor, isToken));
+
             case SyntaxKind.MethodDeclaration:
                 return updateMethod(<MethodDeclaration>node,
                     nodesVisitor((<MethodDeclaration>node).decorators, visitor, isDecorator),
@@ -404,7 +317,99 @@ namespace ts {
                     visitParameterList((<SetAccessorDeclaration>node).parameters, visitor, context, nodesVisitor),
                     visitFunctionBody((<SetAccessorDeclaration>node).body, visitor, context));
 
+            case SyntaxKind.CallSignature:
+                return updateCallSignature(<CallSignatureDeclaration>node,
+                    nodesVisitor((<CallSignatureDeclaration>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<CallSignatureDeclaration>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<CallSignatureDeclaration>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.ConstructSignature:
+                return updateConstructSignature(<ConstructSignatureDeclaration>node,
+                    nodesVisitor((<ConstructSignatureDeclaration>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<ConstructSignatureDeclaration>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<ConstructSignatureDeclaration>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.IndexSignature:
+                return updateIndexSignature(<IndexSignatureDeclaration>node,
+                    nodesVisitor((<IndexSignatureDeclaration>node).decorators, visitor, isDecorator),
+                    nodesVisitor((<IndexSignatureDeclaration>node).modifiers, visitor, isModifier),
+                    nodesVisitor((<IndexSignatureDeclaration>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<IndexSignatureDeclaration>node).type, visitor, isTypeNode));
+
+            // Types
+
+            case SyntaxKind.TypePredicate:
+                return updateTypePredicateNode(<TypePredicateNode>node,
+                    visitNode((<TypePredicateNode>node).parameterName, visitor),
+                    visitNode((<TypePredicateNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.TypeReference:
+                return updateTypeReferenceNode(<TypeReferenceNode>node,
+                    visitNode((<TypeReferenceNode>node).typeName, visitor, isEntityName),
+                    nodesVisitor((<TypeReferenceNode>node).typeArguments, visitor, isTypeNode));
+
+            case SyntaxKind.FunctionType:
+                return updateFunctionTypeNode(<FunctionTypeNode>node,
+                    nodesVisitor((<FunctionTypeNode>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<FunctionTypeNode>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<FunctionTypeNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.ConstructorType:
+                return updateConstructorTypeNode(<ConstructorTypeNode>node,
+                    nodesVisitor((<ConstructorTypeNode>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<ConstructorTypeNode>node).parameters, visitor, isParameterDeclaration),
+                    visitNode((<ConstructorTypeNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.TypeQuery:
+                return updateTypeQueryNode((<TypeQueryNode>node),
+                    visitNode((<TypeQueryNode>node).exprName, visitor, isEntityName));
+
+            case SyntaxKind.TypeLiteral:
+                return updateTypeLiteralNode((<TypeLiteralNode>node),
+                    nodesVisitor((<TypeLiteralNode>node).members, visitor, isTypeElement));
+
+            case SyntaxKind.ArrayType:
+                return updateArrayTypeNode(<ArrayTypeNode>node,
+                    visitNode((<ArrayTypeNode>node).elementType, visitor, isTypeNode));
+
+            case SyntaxKind.TupleType:
+                return updateTypleTypeNode((<TupleTypeNode>node),
+                    nodesVisitor((<TupleTypeNode>node).elementTypes, visitor, isTypeNode));
+
+            case SyntaxKind.UnionType:
+                return updateUnionTypeNode(<UnionTypeNode>node,
+                    nodesVisitor((<UnionTypeNode>node).types, visitor, isTypeNode));
+
+            case SyntaxKind.IntersectionType:
+                return updateIntersectionTypeNode(<IntersectionTypeNode>node,
+                    nodesVisitor((<IntersectionTypeNode>node).types, visitor, isTypeNode));
+
+            case SyntaxKind.ParenthesizedType:
+                return updateParenthesizedType(<ParenthesizedTypeNode>node,
+                    visitNode((<ParenthesizedTypeNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.TypeOperator:
+                return updateTypeOperatorNode(<TypeOperatorNode>node,
+                    visitNode((<TypeOperatorNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.IndexedAccessType:
+                return updateIndexedAccessTypeNode((<IndexedAccessTypeNode>node),
+                    visitNode((<IndexedAccessTypeNode>node).objectType, visitor, isTypeNode),
+                    visitNode((<IndexedAccessTypeNode>node).indexType, visitor, isTypeNode));
+
+            case SyntaxKind.MappedType:
+                return updateMappedTypeNode((<MappedTypeNode>node),
+                    visitNode((<MappedTypeNode>node).readonlyToken, tokenVisitor, isToken),
+                    visitNode((<MappedTypeNode>node).typeParameter, visitor, isTypeParameter),
+                    visitNode((<MappedTypeNode>node).questionToken, tokenVisitor, isToken),
+                    visitNode((<MappedTypeNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.LiteralType:
+                return updateLiteralTypeNode(<LiteralTypeNode>node,
+                    visitNode((<LiteralTypeNode>node).literal, visitor, isExpression));
+
             // Binding patterns
+
             case SyntaxKind.ObjectBindingPattern:
                 return updateObjectBindingPattern(<ObjectBindingPattern>node,
                     nodesVisitor((<ObjectBindingPattern>node).elements, visitor, isBindingElement));
@@ -421,6 +426,7 @@ namespace ts {
                     visitNode((<BindingElement>node).initializer, visitor, isExpression));
 
             // Expression
+
             case SyntaxKind.ArrayLiteralExpression:
                 return updateArrayLiteral(<ArrayLiteralExpression>node,
                     nodesVisitor((<ArrayLiteralExpression>node).elements, visitor, isExpression));
@@ -499,11 +505,6 @@ namespace ts {
                 return updateAwait(<AwaitExpression>node,
                     visitNode((<AwaitExpression>node).expression, visitor, isExpression));
 
-            case SyntaxKind.BinaryExpression:
-                return updateBinary(<BinaryExpression>node,
-                    visitNode((<BinaryExpression>node).left, visitor, isExpression),
-                    visitNode((<BinaryExpression>node).right, visitor, isExpression));
-
             case SyntaxKind.PrefixUnaryExpression:
                 return updatePrefix(<PrefixUnaryExpression>node,
                     visitNode((<PrefixUnaryExpression>node).operand, visitor, isExpression));
@@ -512,6 +513,11 @@ namespace ts {
                 return updatePostfix(<PostfixUnaryExpression>node,
                     visitNode((<PostfixUnaryExpression>node).operand, visitor, isExpression));
 
+            case SyntaxKind.BinaryExpression:
+                return updateBinary(<BinaryExpression>node,
+                    visitNode((<BinaryExpression>node).left, visitor, isExpression),
+                    visitNode((<BinaryExpression>node).right, visitor, isExpression));
+
             case SyntaxKind.ConditionalExpression:
                 return updateConditional(<ConditionalExpression>node,
                     visitNode((<ConditionalExpression>node).condition, visitor, isExpression),
@@ -554,13 +560,19 @@ namespace ts {
                 return updateNonNullExpression(<NonNullExpression>node,
                     visitNode((<NonNullExpression>node).expression, visitor, isExpression));
 
+            case SyntaxKind.MetaProperty:
+                return updateMetaProperty(<MetaProperty>node,
+                    visitNode((<MetaProperty>node).name, visitor, isIdentifier));
+
             // Misc
+
             case SyntaxKind.TemplateSpan:
                 return updateTemplateSpan(<TemplateSpan>node,
                     visitNode((<TemplateSpan>node).expression, visitor, isExpression),
                     visitNode((<TemplateSpan>node).literal, visitor, isTemplateMiddleOrTemplateTail));
 
             // Element
+
             case SyntaxKind.Block:
                 return updateBlock(<Block>node,
                     nodesVisitor((<Block>node).statements, visitor, isStatement));
@@ -677,6 +689,21 @@ namespace ts {
                     nodesVisitor((<ClassDeclaration>node).heritageClauses, visitor, isHeritageClause),
                     nodesVisitor((<ClassDeclaration>node).members, visitor, isClassElement));
 
+            case SyntaxKind.InterfaceDeclaration:
+                return updateInterfaceDeclaration(<InterfaceDeclaration>node,
+                    nodesVisitor((<InterfaceDeclaration>node).decorators, visitor, isDecorator),
+                    nodesVisitor((<InterfaceDeclaration>node).modifiers, visitor, isModifier),
+                    visitNode((<InterfaceDeclaration>node).name, visitor, isIdentifier),
+                    nodesVisitor((<InterfaceDeclaration>node).typeParameters, visitor, isTypeParameter),
+                    nodesVisitor((<InterfaceDeclaration>node).heritageClauses, visitor, isHeritageClause),
+                    nodesVisitor((<InterfaceDeclaration>node).members, visitor, isTypeElement));
+
+            case SyntaxKind.TypeAliasDeclaration:
+                return updateTypeAliasDeclaration(<TypeAliasDeclaration>node,
+                    visitNode((<TypeAliasDeclaration>node).name, visitor, isIdentifier),
+                    nodesVisitor((<TypeAliasDeclaration>node).typeParameters, visitor, isTypeParameter),
+                    visitNode((<TypeAliasDeclaration>node).type, visitor, isTypeNode));
+
             case SyntaxKind.EnumDeclaration:
                 return updateEnumDeclaration(<EnumDeclaration>node,
                     nodesVisitor((<EnumDeclaration>node).decorators, visitor, isDecorator),
@@ -699,6 +726,10 @@ namespace ts {
                 return updateCaseBlock(<CaseBlock>node,
                     nodesVisitor((<CaseBlock>node).clauses, visitor, isCaseOrDefaultClause));
 
+            case SyntaxKind.NamespaceExportDeclaration:
+                return updateNamespaceExportDeclaration(<NamespaceExportDeclaration>node,
+                    visitNode((<NamespaceExportDeclaration>node).name, visitor, isIdentifier));
+
             case SyntaxKind.ImportEqualsDeclaration:
                 return updateImportEqualsDeclaration(<ImportEqualsDeclaration>node,
                     nodesVisitor((<ImportEqualsDeclaration>node).decorators, visitor, isDecorator),
@@ -754,21 +785,19 @@ namespace ts {
                     visitNode((<ExportSpecifier>node).name, visitor, isIdentifier));
 
             // Module references
+
             case SyntaxKind.ExternalModuleReference:
                 return updateExternalModuleReference(<ExternalModuleReference>node,
                     visitNode((<ExternalModuleReference>node).expression, visitor, isExpression));
 
             // JSX
+
             case SyntaxKind.JsxElement:
                 return updateJsxElement(<JsxElement>node,
                     visitNode((<JsxElement>node).openingElement, visitor, isJsxOpeningElement),
                     nodesVisitor((<JsxElement>node).children, visitor, isJsxChild),
                     visitNode((<JsxElement>node).closingElement, visitor, isJsxClosingElement));
 
-            case SyntaxKind.JsxAttributes:
-                return updateJsxAttributes(<JsxAttributes>node,
-                    nodesVisitor((<JsxAttributes>node).properties, visitor, isJsxAttributeLike));
-
             case SyntaxKind.JsxSelfClosingElement:
                 return updateJsxSelfClosingElement(<JsxSelfClosingElement>node,
                     visitNode((<JsxSelfClosingElement>node).tagName, visitor, isJsxTagNameExpression),
@@ -788,6 +817,10 @@ namespace ts {
                     visitNode((<JsxAttribute>node).name, visitor, isIdentifier),
                     visitNode((<JsxAttribute>node).initializer, visitor, isStringLiteralOrJsxExpression));
 
+            case SyntaxKind.JsxAttributes:
+                return updateJsxAttributes(<JsxAttributes>node,
+                    nodesVisitor((<JsxAttributes>node).properties, visitor, isJsxAttributeLike));
+
             case SyntaxKind.JsxSpreadAttribute:
                 return updateJsxSpreadAttribute(<JsxSpreadAttribute>node,
                     visitNode((<JsxSpreadAttribute>node).expression, visitor, isExpression));
@@ -797,6 +830,7 @@ namespace ts {
                     visitNode((<JsxExpression>node).expression, visitor, isExpression));
 
             // Clauses
+
             case SyntaxKind.CaseClause:
                 return updateCaseClause(<CaseClause>node,
                     visitNode((<CaseClause>node).expression, visitor, isExpression),
@@ -816,6 +850,7 @@ namespace ts {
                     visitNode((<CatchClause>node).block, visitor, isBlock));
 
             // Property assignments
+
             case SyntaxKind.PropertyAssignment:
                 return updatePropertyAssignment(<PropertyAssignment>node,
                     visitNode((<PropertyAssignment>node).name, visitor, isPropertyName),
@@ -846,9 +881,15 @@ namespace ts {
                 return updatePartiallyEmittedExpression(<PartiallyEmittedExpression>node,
                     visitNode((<PartiallyEmittedExpression>node).expression, visitor, isExpression));
 
+            case SyntaxKind.CommaListExpression:
+                return updateCommaList(<CommaListExpression>node,
+                    nodesVisitor((<CommaListExpression>node).elements, visitor, isExpression));
+
             default:
+                // No need to visit nodes with no children.
                 return node;
         }
+
     }
 
     /**
@@ -934,6 +975,15 @@ namespace ts {
                 break;
 
             // Type member
+
+            case SyntaxKind.PropertySignature:
+                result = reduceNodes((<PropertySignature>node).modifiers, cbNodes, result);
+                result = reduceNode((<PropertySignature>node).name, cbNode, result);
+                result = reduceNode((<PropertySignature>node).questionToken, cbNode, result);
+                result = reduceNode((<PropertySignature>node).type, cbNode, result);
+                result = reduceNode((<PropertySignature>node).initializer, cbNode, result);
+                break;
+
             case SyntaxKind.PropertyDeclaration:
                 result = reduceNodes((<PropertyDeclaration>node).decorators, cbNodes, result);
                 result = reduceNodes((<PropertyDeclaration>node).modifiers, cbNodes, result);
@@ -1357,6 +1407,10 @@ namespace ts {
                 result = reduceNode((<PartiallyEmittedExpression>node).expression, cbNode, result);
                 break;
 
+            case SyntaxKind.CommaListExpression:
+                result = reduceNodes((<CommaListExpression>node).elements, cbNodes, result);
+                break;
+
             default:
                 break;
         }