Merge branch 'master' into cleanupDiagnostics

bin/lib.core.d.ts

@@ -179,19 +179,19 @@ interface ObjectConstructor {
       * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes. 
       */
-    seal(o: any): any;
+    seal<T>(o: T): T;
 
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.
       */
-    freeze(o: any): any;
+    freeze<T>(o: T): T;
 
     /**
       * Prevents the addition of new properties to an object.
       * @param o Object to make non-extensible. 
       */
-    preventExtensions(o: any): any;
+    preventExtensions<T>(o: T): T;
 
     /**
       * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
@@ -425,6 +425,9 @@ interface String {
       */
     substr(from: number, length?: number): string;
 
+    /** Returns the primitive value of the specified object. */
+    valueOf(): string;
+
     [index: number]: string;
 }
 
@@ -477,6 +480,9 @@ interface Number {
       * @param precision Number of significant digits. Must be in the range 1 - 21, inclusive.
       */
     toPrecision(precision?: number): string;
+
+    /** Returns the primitive value of the specified object. */
+    valueOf(): number;
 }
 
 interface NumberConstructor {

bin/lib.core.es6.d.ts

@@ -179,19 +179,19 @@ interface ObjectConstructor {
       * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes. 
       */
-    seal(o: any): any;
+    seal<T>(o: T): T;
 
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.
       */
-    freeze(o: any): any;
+    freeze<T>(o: T): T;
 
     /**
       * Prevents the addition of new properties to an object.
       * @param o Object to make non-extensible. 
       */
-    preventExtensions(o: any): any;
+    preventExtensions<T>(o: T): T;
 
     /**
       * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
@@ -425,6 +425,9 @@ interface String {
       */
     substr(from: number, length?: number): string;
 
+    /** Returns the primitive value of the specified object. */
+    valueOf(): string;
+
     [index: number]: string;
 }
 
@@ -477,6 +480,9 @@ interface Number {
       * @param precision Number of significant digits. Must be in the range 1 - 21, inclusive.
       */
     toPrecision(precision?: number): string;
+
+    /** Returns the primitive value of the specified object. */
+    valueOf(): number;
 }
 
 interface NumberConstructor {

bin/lib.d.ts

@@ -179,19 +179,19 @@ interface ObjectConstructor {
       * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes. 
       */
-    seal(o: any): any;
+    seal<T>(o: T): T;
 
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.
       */
-    freeze(o: any): any;
+    freeze<T>(o: T): T;
 
     /**
       * Prevents the addition of new properties to an object.
       * @param o Object to make non-extensible. 
       */
-    preventExtensions(o: any): any;
+    preventExtensions<T>(o: T): T;
 
     /**
       * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
@@ -425,6 +425,9 @@ interface String {
       */
     substr(from: number, length?: number): string;
 
+    /** Returns the primitive value of the specified object. */
+    valueOf(): string;
+
     [index: number]: string;
 }
 
@@ -477,6 +480,9 @@ interface Number {
       * @param precision Number of significant digits. Must be in the range 1 - 21, inclusive.
       */
     toPrecision(precision?: number): string;
+
+    /** Returns the primitive value of the specified object. */
+    valueOf(): number;
 }
 
 interface NumberConstructor {

bin/lib.es6.d.ts

@@ -179,19 +179,19 @@ interface ObjectConstructor {
       * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes. 
       */
-    seal(o: any): any;
+    seal<T>(o: T): T;
 
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.
       */
-    freeze(o: any): any;
+    freeze<T>(o: T): T;
 
     /**
       * Prevents the addition of new properties to an object.
       * @param o Object to make non-extensible. 
       */
-    preventExtensions(o: any): any;
+    preventExtensions<T>(o: T): T;
 
     /**
       * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.
@@ -425,6 +425,9 @@ interface String {
       */
     substr(from: number, length?: number): string;
 
+    /** Returns the primitive value of the specified object. */
+    valueOf(): string;
+
     [index: number]: string;
 }
 
@@ -477,6 +480,9 @@ interface Number {
       * @param precision Number of significant digits. Must be in the range 1 - 21, inclusive.
       */
     toPrecision(precision?: number): string;
+
+    /** Returns the primitive value of the specified object. */
+    valueOf(): number;
 }
 
 interface NumberConstructor {

bin/typescript.d.ts

@@ -224,27 +224,28 @@ declare module "typescript" {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -619,6 +620,9 @@ declare module "typescript" {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1197,6 +1201,7 @@ declare module "typescript" {
         version?: boolean;
         watch?: boolean;
         stripInternal?: boolean;
+        preserveNewLines?: boolean;
         [option: string]: string | number | boolean;
     }
     const enum ModuleKind {
@@ -1437,12 +1442,15 @@ declare module "typescript" {
     function createTypeChecker(host: TypeCheckerHost, produceDiagnostics: boolean): TypeChecker;
 }
 declare module "typescript" {
+    /** The version of the TypeScript compiler release */
+    var version: string;
     function createCompilerHost(options: CompilerOptions): CompilerHost;
     function getPreEmitDiagnostics(program: Program): Diagnostic[];
     function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string;
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost): Program;
 }
 declare module "typescript" {
+    /** The version of the language service API */
     var servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;

bin/typescriptServices.d.ts

@@ -224,27 +224,28 @@ declare module ts {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -619,6 +620,9 @@ declare module ts {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1197,6 +1201,7 @@ declare module ts {
         version?: boolean;
         watch?: boolean;
         stripInternal?: boolean;
+        preserveNewLines?: boolean;
         [option: string]: string | number | boolean;
     }
     const enum ModuleKind {
@@ -1437,12 +1442,15 @@ declare module ts {
     function createTypeChecker(host: TypeCheckerHost, produceDiagnostics: boolean): TypeChecker;
 }
 declare module ts {
+    /** The version of the TypeScript compiler release */
+    var version: string;
     function createCompilerHost(options: CompilerOptions): CompilerHost;
     function getPreEmitDiagnostics(program: Program): Diagnostic[];
     function flattenDiagnosticMessageText(messageText: string | DiagnosticMessageChain, newLine: string): string;
     function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost): Program;
 }
 declare module ts {
+    /** The version of the language service API */
     var servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;

bin/typescriptServices_internal.d.ts

@@ -171,6 +171,7 @@ declare module ts {
     function unescapeIdentifier(identifier: string): string;
     function makeIdentifierFromModuleName(moduleName: string): string;
     function isBlockOrCatchScoped(declaration: Declaration): boolean;
+    function getEnclosingBlockScopeContainer(node: Node): Node;
     function isCatchClauseVariableDeclaration(declaration: Declaration): boolean;
     function declarationNameToString(name: DeclarationName): string;
     function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): Diagnostic;
@@ -270,7 +271,6 @@ declare module ts {
     function nodeIsSynthesized(node: Node): boolean;
     function createSynthesizedNode(kind: SyntaxKind, startsOnNewLine?: boolean): Node;
     function generateUniqueName(baseName: string, isExistingName: (name: string) => boolean): string;
-    function createDiagnosticCollection(): DiagnosticCollection;
     /**
      * Based heavily on the abstract 'Quote'/'QuoteJSONString' operation from ECMA-262 (24.3.2.2),
      * but augmented for a few select characters (e.g. lineSeparator, paragraphSeparator, nextLine)

bin/typescript_internal.d.ts

@@ -171,6 +171,7 @@ declare module "typescript" {
     function unescapeIdentifier(identifier: string): string;
     function makeIdentifierFromModuleName(moduleName: string): string;
     function isBlockOrCatchScoped(declaration: Declaration): boolean;
+    function getEnclosingBlockScopeContainer(node: Node): Node;
     function isCatchClauseVariableDeclaration(declaration: Declaration): boolean;
     function declarationNameToString(name: DeclarationName): string;
     function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): Diagnostic;
@@ -270,7 +271,6 @@ declare module "typescript" {
     function nodeIsSynthesized(node: Node): boolean;
     function createSynthesizedNode(kind: SyntaxKind, startsOnNewLine?: boolean): Node;
     function generateUniqueName(baseName: string, isExistingName: (name: string) => boolean): string;
-    function createDiagnosticCollection(): DiagnosticCollection;
     /**
      * Based heavily on the abstract 'Quote'/'QuoteJSONString' operation from ECMA-262 (24.3.2.2),
      * but augmented for a few select characters (e.g. lineSeparator, paragraphSeparator, nextLine)

src/compiler/binder.ts

@@ -1,7 +1,7 @@
 /// <reference path="parser.ts"/>
 
 module ts {
-    /* @internal */ export var bindTime = 0;
+    /* @internal */ export let bindTime = 0;
 
     export const enum ModuleInstanceState {
         NonInstantiated = 0,
@@ -25,7 +25,7 @@ module ts {
         }
         // 4. other uninstantiated module declarations.
         else if (node.kind === SyntaxKind.ModuleBlock) {
-            var state = ModuleInstanceState.NonInstantiated;
+            let state = ModuleInstanceState.NonInstantiated;
             forEachChild(node, n => {
                 switch (getModuleInstanceState(n)) {
                     case ModuleInstanceState.NonInstantiated:
@@ -52,18 +52,18 @@ module ts {
     }
 
     export function bindSourceFile(file: SourceFile): void {
-        var start = new Date().getTime();
+        let start = new Date().getTime();
         bindSourceFileWorker(file);
         bindTime += new Date().getTime() - start;
     }
 
     function bindSourceFileWorker(file: SourceFile): void {
         var parent: Node;
-        var container: Node;
-        var blockScopeContainer: Node;
-        var lastContainer: Node;
-        var symbolCount = 0;
-        var Symbol = objectAllocator.getSymbolConstructor();
+        let container: Node;
+        let blockScopeContainer: Node;
+        let lastContainer: Node;
+        let symbolCount = 0;
+        let Symbol = objectAllocator.getSymbolConstructor();
 
         if (!file.locals) {
             file.locals = {};
@@ -103,7 +103,7 @@ module ts {
                     return '"' + (<LiteralExpression>node.name).text + '"';
                 }
                 if (node.name.kind === SyntaxKind.ComputedPropertyName) {
-                    var nameExpression = (<ComputedPropertyName>node.name).expression;
+                    let nameExpression = (<ComputedPropertyName>node.name).expression;
                     Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
                     return getPropertyNameForKnownSymbolName((<PropertyAccessExpression>nameExpression).name.text);
                 }
@@ -138,10 +138,11 @@ module ts {
             Debug.assert(!hasDynamicName(node));
 
             // The exported symbol for an export default function/class node is always named "default"
-            var name = node.flags & NodeFlags.Default && parent ? "default" : getDeclarationName(node);
+            let name = node.flags & NodeFlags.Default && parent ? "default" : getDeclarationName(node);
 
+            let symbol: Symbol;
             if (name !== undefined) {
-                var symbol = hasProperty(symbols, name) ? symbols[name] : (symbols[name] = createSymbol(0, name));
+                symbol = hasProperty(symbols, name) ? symbols[name] : (symbols[name] = createSymbol(0, name));
                 if (symbol.flags & excludes) {
                     if (node.name) {
                         node.name.parent = node;
@@ -149,7 +150,7 @@ module ts {
 
                     // Report errors every position with duplicate declaration
                     // Report errors on previous encountered declarations
-                    var message = symbol.flags & SymbolFlags.BlockScopedVariable
+                    let message = symbol.flags & SymbolFlags.BlockScopedVariable
                         ? Diagnostics.Cannot_redeclare_block_scoped_variable_0 
                         : Diagnostics.Duplicate_identifier_0;
 
@@ -172,7 +173,7 @@ module ts {
                 // Every class automatically contains a static property member named 'prototype', 
                 // the type of which is an instantiation of the class type with type Any supplied as a type argument for each type parameter.
                 // It is an error to explicitly declare a static property member with the name 'prototype'.
-                var prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
+                let prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
                 if (hasProperty(symbol.exports, prototypeSymbol.name)) {
                     if (node.name) {
                         node.name.parent = node;
@@ -196,7 +197,7 @@ module ts {
         }
 
         function declareModuleMember(node: Declaration, symbolKind: SymbolFlags, symbolExcludes: SymbolFlags) {
-            var hasExportModifier = getCombinedNodeFlags(node) & NodeFlags.Export;
+            let hasExportModifier = getCombinedNodeFlags(node) & NodeFlags.Export;
             if (symbolKind & SymbolFlags.Alias) {
                 if (node.kind === SyntaxKind.ExportSpecifier || (node.kind === SyntaxKind.ImportEqualsDeclaration && hasExportModifier)) {
                     declareSymbol(container.symbol.exports, container.symbol, node, symbolKind, symbolExcludes);
@@ -218,10 +219,10 @@ module ts {
                 //      but return the export symbol (by calling getExportSymbolOfValueSymbolIfExported). That way
                 //      when the emitter comes back to it, it knows not to qualify the name if it was found in a containing scope.
                 if (hasExportModifier || isAmbientContext(container)) {
-                    var exportKind = (symbolKind & SymbolFlags.Value ? SymbolFlags.ExportValue : 0) |
+                    let exportKind = (symbolKind & SymbolFlags.Value ? SymbolFlags.ExportValue : 0) |
                         (symbolKind & SymbolFlags.Type ? SymbolFlags.ExportType : 0) |
                         (symbolKind & SymbolFlags.Namespace ? SymbolFlags.ExportNamespace : 0);
-                    var local = declareSymbol(container.locals, undefined, node, exportKind, symbolExcludes);
+                    let local = declareSymbol(container.locals, undefined, node, exportKind, symbolExcludes);
                     local.exportSymbol = declareSymbol(container.symbol.exports, container.symbol, node, symbolKind, symbolExcludes);
                     node.localSymbol = local;
                 }
@@ -238,9 +239,9 @@ module ts {
                 node.locals = {};
             }
 
-            var saveParent = parent;
-            var saveContainer = container;
-            var savedBlockScopeContainer = blockScopeContainer;
+            let saveParent = parent;
+            let saveContainer = container;
+            let savedBlockScopeContainer = blockScopeContainer;
             parent = node;
             if (symbolKind & SymbolFlags.IsContainer) {
                 container = node;
@@ -315,7 +316,7 @@ module ts {
                 bindDeclaration(node, SymbolFlags.ValueModule, SymbolFlags.ValueModuleExcludes, /*isBlockScopeContainer*/ true);
             }
             else {
-                var state = getModuleInstanceState(node);
+                let state = getModuleInstanceState(node);
                 if (state === ModuleInstanceState.NonInstantiated) {
                     bindDeclaration(node, SymbolFlags.NamespaceModule, SymbolFlags.NamespaceModuleExcludes, /*isBlockScopeContainer*/ true);
                 }
@@ -341,18 +342,18 @@ module ts {
             // symbol as its sole member. To the rest of the system, this symbol will be  indistinguishable 
             // from an actual type literal symbol you would have gotten had you used the long form.
 
-            var symbol = createSymbol(SymbolFlags.Signature, getDeclarationName(node));
+            let symbol = createSymbol(SymbolFlags.Signature, getDeclarationName(node));
             addDeclarationToSymbol(symbol, node, SymbolFlags.Signature);
             bindChildren(node, SymbolFlags.Signature, /*isBlockScopeContainer:*/ false);
 
-            var typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
+            let typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
             addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
             typeLiteralSymbol.members = {};
             typeLiteralSymbol.members[node.kind === SyntaxKind.FunctionType ? "__call" : "__new"] = symbol
         }
 
         function bindAnonymousDeclaration(node: Declaration, symbolKind: SymbolFlags, name: string, isBlockScopeContainer: boolean) {
-            var symbol = createSymbol(symbolKind, name);
+            let symbol = createSymbol(symbolKind, name);
             addDeclarationToSymbol(symbol, node, symbolKind);
             bindChildren(node, symbolKind, isBlockScopeContainer);
         }
@@ -525,20 +526,20 @@ module ts {
                     // Otherwise this won't be considered as redeclaration of a block scoped local:
                     // function foo() {
                     //  let x;
-                    //  var x;
+                    //  let x;
                     // }
-                    // 'var x' will be placed into the function locals and 'let x' - into the locals of the block
+                    // 'let x' will be placed into the function locals and 'let x' - into the locals of the block
                     bindChildren(node, 0, /*isBlockScopeContainer*/ !isFunctionLike(node.parent));
                     break;
                 case SyntaxKind.CatchClause:
                 case SyntaxKind.ForStatement:
                 case SyntaxKind.ForInStatement:
                 case SyntaxKind.ForOfStatement:
-                case SyntaxKind.SwitchStatement:
+                case SyntaxKind.CaseBlock:
                     bindChildren(node, 0, /*isBlockScopeContainer*/ true);
                     break;
                 default:
-                    var saveParent = parent;
+                    let saveParent = parent;
                     parent = node;
                     forEachChild(node, bind);
                     parent = saveParent;
@@ -559,7 +560,7 @@ module ts {
                 node.parent.kind === SyntaxKind.Constructor &&
                 node.parent.parent.kind === SyntaxKind.ClassDeclaration) {
 
-                var classDeclaration = <ClassDeclaration>node.parent.parent;
+                let classDeclaration = <ClassDeclaration>node.parent.parent;
                 declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
             }
         }

src/compiler/core.ts

@@ -25,8 +25,8 @@ module ts {
 
     export function forEach<T, U>(array: T[], callback: (element: T, index: number) => U): U {
         if (array) {
-            for (var i = 0, len = array.length; i < len; i++) {
-                var result = callback(array[i], i);
+            for (let i = 0, len = array.length; i < len; i++) {
+                let result = callback(array[i], i);
                 if (result) {
                     return result;
                 }
@@ -37,8 +37,8 @@ module ts {
 
     export function contains<T>(array: T[], value: T): boolean {
         if (array) {
-            for (var i = 0, len = array.length; i < len; i++) {
-                if (array[i] === value) {
+            for (let v of array) {
+                if (v === value) {
                     return true;
                 }
             }
@@ -48,7 +48,7 @@ module ts {
 
     export function indexOf<T>(array: T[], value: T): number {
         if (array) {
-            for (var i = 0, len = array.length; i < len; i++) {
+            for (let i = 0, len = array.length; i < len; i++) {
                 if (array[i] === value) {
                     return i;
                 }
@@ -58,10 +58,10 @@ module ts {
     }
 
     export function countWhere<T>(array: T[], predicate: (x: T) => boolean): number {
-        var count = 0;
+        let count = 0;
         if (array) {
-            for (var i = 0, len = array.length; i < len; i++) {
-                if (predicate(array[i])) {
+            for (let v of array) {
+                if (predicate(v)) {
                     count++;
                 }
             }
@@ -69,11 +69,11 @@ module ts {
         return count;
     }
 
-    export function filter<T>(array: T[], f: (x: T) => boolean): T[] {
+    export function filter<T>(array: T[], f: (x: T) => boolean): T[]{
+        let result: T[];
         if (array) {
-            var result: T[] = [];
-            for (var i = 0, len = array.length; i < len; i++) {
-                var item = array[i];
+            result = [];
+            for (let item of array) {
                 if (f(item)) {
                     result.push(item);
                 }
@@ -82,11 +82,12 @@ module ts {
         return result;
     }
 
-    export function map<T, U>(array: T[], f: (x: T) => U): U[] {
+    export function map<T, U>(array: T[], f: (x: T) => U): U[]{
+        let result: U[];
         if (array) {
-            var result: U[] = [];
-            for (var i = 0, len = array.length; i < len; i++) {
-                result.push(f(array[i]));
+            result = [];
+            for (let v of array) {
+                result.push(f(v));
             }
         }
         return result;
@@ -99,28 +100,30 @@ module ts {
         return array1.concat(array2);
     }
 
-    export function deduplicate<T>(array: T[]): T[] {
+    export function deduplicate<T>(array: T[]): T[]{
+        let result: T[];
         if (array) {
-            var result: T[] = [];
-            for (var i = 0, len = array.length; i < len; i++) {
-                var item = array[i];
-                if (!contains(result, item)) result.push(item);
+            result = [];
+            for (let item of array) {
+                if (!contains(result, item)) {
+                    result.push(item);
+                }
             }
         }
         return result;
     }
 
     export function sum(array: any[], prop: string): number {
-        var result = 0;
-        for (var i = 0; i < array.length; i++) {
-            result += array[i][prop];
+        let result = 0;
+        for (let v of array) {
+            result += v[prop];
         }
         return result;
     }
 
     export function addRange<T>(to: T[], from: T[]): void {
-        for (var i = 0, n = from.length; i < n; i++) {
-            to.push(from[i]);
+        for (let v of from) {
+            to.push(v);
         }
     } 
 
@@ -136,12 +139,12 @@ module ts {
     }
 
     export function binarySearch(array: number[], value: number): number {
-        var low = 0;
-        var high = array.length - 1;
+        let low = 0;
+        let high = array.length - 1;
 
         while (low <= high) {
-            var middle = low + ((high - low) >> 1);
-            var midValue = array[middle];
+            let middle = low + ((high - low) >> 1);
+            let midValue = array[middle];
 
             if (midValue === value) {
                 return middle;
@@ -157,7 +160,7 @@ module ts {
         return ~low;
     }
 
-    var hasOwnProperty = Object.prototype.hasOwnProperty;
+    let hasOwnProperty = Object.prototype.hasOwnProperty;
 
     export function hasProperty<T>(map: Map<T>, key: string): boolean {
         return hasOwnProperty.call(map, key);
@@ -168,7 +171,7 @@ module ts {
     }
 
     export function isEmpty<T>(map: Map<T>) {
-        for (var id in map) {
+        for (let id in map) {
             if (hasProperty(map, id)) {
                 return false;
             }
@@ -177,19 +180,19 @@ module ts {
     }
 
     export function clone<T>(object: T): T {
-        var result: any = {};
-        for (var id in object) {
+        let result: any = {};
+        for (let id in object) {
             result[id] = (<any>object)[id];
         }
         return <T>result;
     }
 
     export function extend<T>(first: Map<T>, second: Map<T>): Map<T> {
-        var result: Map<T> = {};
-        for (var id in first) {
+        let result: Map<T> = {};
+        for (let id in first) {
             result[id] = first[id];
         }
-        for (var id in second) {
+        for (let id in second) {
             if (!hasProperty(result, id)) {
                 result[id] = second[id];
             }
@@ -198,16 +201,16 @@ module ts {
     }
 
     export function forEachValue<T, U>(map: Map<T>, callback: (value: T) => U): U {
-        var result: U;
-        for (var id in map) {
+        let result: U;
+        for (let id in map) {
             if (result = callback(map[id])) break;
         }
         return result;
     }
 
     export function forEachKey<T, U>(map: Map<T>, callback: (key: string) => U): U {
-        var result: U;
-        for (var id in map) {
+        let result: U;
+        for (let id in map) {
             if (result = callback(id)) break;
         }
         return result;
@@ -218,9 +221,9 @@ module ts {
     }
 
     export function mapToArray<T>(map: Map<T>): T[] {
-        var result: T[] = [];
+        let result: T[] = [];
 
-        for (var id in map) {
+        for (let id in map) {
             result.push(map[id]);
         }
 
@@ -228,7 +231,7 @@ module ts {
     }
 
     export function copyMap<T>(source: Map<T>, target: Map<T>): void {
-        for (var p in source) {
+        for (let p in source) {
             target[p] = source[p];
         }
     }
@@ -244,7 +247,7 @@ module ts {
      * index in the array will be the one associated with the produced key.
      */
     export function arrayToMap<T>(array: T[], makeKey: (value: T) => string): Map<T> {
-        var result: Map<T> = {};
+        let result: Map<T> = {};
 
         forEach(array, value => {
             result[makeKey(value)] = value;
@@ -259,7 +262,7 @@ module ts {
         return text.replace(/{(\d+)}/g, (match, index?) => args[+index + baseIndex]);
     }
 
-    export var localizedDiagnosticMessages: Map<string> = undefined;
+    export let localizedDiagnosticMessages: Map<string> = undefined;
 
     export function getLocaleSpecificMessage(message: string) {
         return localizedDiagnosticMessages && localizedDiagnosticMessages[message]
@@ -269,10 +272,14 @@ module ts {
 
     export function createFileDiagnostic(file: SourceFile, start: number, length: number, message: DiagnosticMessage, ...args: any[]): Diagnostic;
     export function createFileDiagnostic(file: SourceFile, start: number, length: number, message: DiagnosticMessage): Diagnostic {
+        let end = start + length;
+
         Debug.assert(start >= 0, "start must be non-negative, is " + start);
         Debug.assert(length >= 0, "length must be non-negative, is " + length);
+        Debug.assert(start <= file.text.length, `start must be within the bounds of the file. ${ start } > ${ file.text.length }`);
+        Debug.assert(end <= file.text.length, `end must be the bounds of the file. ${ end } > ${ file.text.length }`);
 
-        var text = getLocaleSpecificMessage(message.key);
+        let text = getLocaleSpecificMessage(message.key);
         
         if (arguments.length > 4) {
             text = formatStringFromArgs(text, arguments, 4);
@@ -291,7 +298,7 @@ module ts {
 
     export function createCompilerDiagnostic(message: DiagnosticMessage, ...args: any[]): Diagnostic;
     export function createCompilerDiagnostic(message: DiagnosticMessage): Diagnostic {
-        var text = getLocaleSpecificMessage(message.key);
+        let text = getLocaleSpecificMessage(message.key);
 
         if (arguments.length > 1) {
             text = formatStringFromArgs(text, arguments, 1);
@@ -310,7 +317,7 @@ module ts {
 
     export function chainDiagnosticMessages(details: DiagnosticMessageChain, message: DiagnosticMessage, ...args: any[]): DiagnosticMessageChain;
     export function chainDiagnosticMessages(details: DiagnosticMessageChain, message: DiagnosticMessage): DiagnosticMessageChain {
-        var text = getLocaleSpecificMessage(message.key);
+        let text = getLocaleSpecificMessage(message.key);
 
         if (arguments.length > 2) {
             text = formatStringFromArgs(text, arguments, 2);
@@ -354,10 +361,10 @@ module ts {
     function compareMessageText(text1: string | DiagnosticMessageChain, text2: string | DiagnosticMessageChain): Comparison {
         while (text1 && text2) {
             // We still have both chains.
-            var string1 = typeof text1 === "string" ? text1 : text1.messageText;
-            var string2 = typeof text2 === "string" ? text2 : text2.messageText;
+            let string1 = typeof text1 === "string" ? text1 : text1.messageText;
+            let string2 = typeof text2 === "string" ? text2 : text2.messageText;
 
-            var res = compareValues(string1, string2);
+            let res = compareValues(string1, string2);
             if (res) {
                 return res;
             }
@@ -384,11 +391,11 @@ module ts {
             return diagnostics;
         }
 
-        var newDiagnostics = [diagnostics[0]];
-        var previousDiagnostic = diagnostics[0];
-        for (var i = 1; i < diagnostics.length; i++) {
-            var currentDiagnostic = diagnostics[i];
-            var isDupe = compareDiagnostics(currentDiagnostic, previousDiagnostic) === Comparison.EqualTo;
+        let newDiagnostics = [diagnostics[0]];
+        let previousDiagnostic = diagnostics[0];
+        for (let i = 1; i < diagnostics.length; i++) {
+            let currentDiagnostic = diagnostics[i];
+            let isDupe = compareDiagnostics(currentDiagnostic, previousDiagnostic) === Comparison.EqualTo;
             if (!isDupe) {
                 newDiagnostics.push(currentDiagnostic);
                 previousDiagnostic = currentDiagnostic;
@@ -406,9 +413,9 @@ module ts {
     export function getRootLength(path: string): number {
         if (path.charCodeAt(0) === CharacterCodes.slash) {
             if (path.charCodeAt(1) !== CharacterCodes.slash) return 1;
-            var p1 = path.indexOf("/", 2);
+            let p1 = path.indexOf("/", 2);
             if (p1 < 0) return 2;
-            var p2 = path.indexOf("/", p1 + 1);
+            let p2 = path.indexOf("/", p1 + 1);
             if (p2 < 0) return p1 + 1;
             return p2 + 1;
         }
@@ -419,12 +426,11 @@ module ts {
         return 0;
     }
 
-    export var directorySeparator = "/";
+    export let directorySeparator = "/";
     function getNormalizedParts(normalizedSlashedPath: string, rootLength: number) {
-        var parts = normalizedSlashedPath.substr(rootLength).split(directorySeparator);
-        var normalized: string[] = [];
-        for (var i = 0; i < parts.length; i++) {
-            var part = parts[i];
+        let parts = normalizedSlashedPath.substr(rootLength).split(directorySeparator);
+        let normalized: string[] = [];
+        for (let part of parts) {
             if (part !== ".") {
                 if (part === ".." && normalized.length > 0 && normalized[normalized.length - 1] !== "..") {
                     normalized.pop();
@@ -443,9 +449,9 @@ module ts {
     }
 
     export function normalizePath(path: string): string {
-        var path = normalizeSlashes(path);
-        var rootLength = getRootLength(path);
-        var normalized = getNormalizedParts(path, rootLength);
+        path = normalizeSlashes(path);
+        let rootLength = getRootLength(path);
+        let normalized = getNormalizedParts(path, rootLength);
         return path.substr(0, rootLength) + normalized.join(directorySeparator);
     }
 
@@ -462,13 +468,13 @@ module ts {
     }
 
     function normalizedPathComponents(path: string, rootLength: number) {
-        var normalizedParts = getNormalizedParts(path, rootLength);
+        let normalizedParts = getNormalizedParts(path, rootLength);
         return [path.substr(0, rootLength)].concat(normalizedParts);
     }
 
     export function getNormalizedPathComponents(path: string, currentDirectory: string) {
-        var path = normalizeSlashes(path);
-        var rootLength = getRootLength(path);
+        path = normalizeSlashes(path);
+        let rootLength = getRootLength(path);
         if (rootLength == 0) {
             // If the path is not rooted it is relative to current directory
             path = combinePaths(normalizeSlashes(currentDirectory), path);
@@ -493,9 +499,9 @@ module ts {
         // In this example the root is:  http://www.website.com/ 
         // normalized path components should be ["http://www.website.com/", "folder1", "folder2"]
 
-        var urlLength = url.length;
+        let urlLength = url.length;
         // Initial root length is http:// part
-        var rootLength = url.indexOf("://") + "://".length;
+        let rootLength = url.indexOf("://") + "://".length;
         while (rootLength < urlLength) {
             // Consume all immediate slashes in the protocol 
             // eg.initial rootlength is just file:// but it needs to consume another "/" in file:///
@@ -514,7 +520,7 @@ module ts {
         }
 
         // Find the index of "/" after website.com so the root can be http://www.website.com/ (from existing http://)
-        var indexOfNextSlash = url.indexOf(directorySeparator, rootLength);
+        let indexOfNextSlash = url.indexOf(directorySeparator, rootLength);
         if (indexOfNextSlash !== -1) {
             // Found the "/" after the website.com so the root is length of http://www.website.com/ 
             // and get components afetr the root normally like any other folder components
@@ -540,8 +546,8 @@ module ts {
     }
 
     export function getRelativePathToDirectoryOrUrl(directoryPathOrUrl: string, relativeOrAbsolutePath: string, currentDirectory: string, getCanonicalFileName: (fileName: string) => string, isAbsolutePathAnUrl: boolean) {
-        var pathComponents = getNormalizedPathOrUrlComponents(relativeOrAbsolutePath, currentDirectory);
-        var directoryComponents = getNormalizedPathOrUrlComponents(directoryPathOrUrl, currentDirectory);
+        let pathComponents = getNormalizedPathOrUrlComponents(relativeOrAbsolutePath, currentDirectory);
+        let directoryComponents = getNormalizedPathOrUrlComponents(directoryPathOrUrl, currentDirectory);
         if (directoryComponents.length > 1 && directoryComponents[directoryComponents.length - 1] === "") {
             // If the directory path given was of type test/cases/ then we really need components of directory to be only till its name
             // that is  ["test", "cases", ""] needs to be actually ["test", "cases"]
@@ -557,8 +563,8 @@ module ts {
 
         // Get the relative path
         if (joinStartIndex) {
-            var relativePath = "";
-            var relativePathComponents = pathComponents.slice(joinStartIndex, pathComponents.length);
+            let relativePath = "";
+            let relativePathComponents = pathComponents.slice(joinStartIndex, pathComponents.length);
             for (; joinStartIndex < directoryComponents.length; joinStartIndex++) {
                 if (directoryComponents[joinStartIndex] !== "") {
                     relativePath = relativePath + ".." + directorySeparator;
@@ -569,7 +575,7 @@ module ts {
         }
 
         // Cant find the relative path, get the absolute path
-        var absolutePath = getNormalizedPathFromPathComponents(pathComponents);
+        let absolutePath = getNormalizedPathFromPathComponents(pathComponents);
         if (isAbsolutePathAnUrl && isRootedDiskPath(absolutePath)) {
             absolutePath = "file:///" + absolutePath;
         }
@@ -578,7 +584,7 @@ module ts {
     }
 
     export function getBaseFileName(path: string) {
-        var i = path.lastIndexOf(directorySeparator);
+        let i = path.lastIndexOf(directorySeparator);
         return i < 0 ? path : path.substring(i + 1);
     }
 
@@ -591,16 +597,15 @@ module ts {
     }
 
     export function fileExtensionIs(path: string, extension: string): boolean {
-        var pathLen = path.length;
-        var extLen = extension.length;
+        let pathLen = path.length;
+        let extLen = extension.length;
         return pathLen > extLen && path.substr(pathLen - extLen, extLen) === extension;
     }
 
-    var supportedExtensions = [".d.ts", ".ts", ".js"];
+    let supportedExtensions = [".d.ts", ".ts", ".js"];
 
     export function removeFileExtension(path: string): string {
-        for (var i = 0; i < supportedExtensions.length; i++) {
-            var ext = supportedExtensions[i];
+        for (let ext of supportedExtensions) {
 
             if (fileExtensionIs(path, ext)) {
                 return path.substr(0, path.length - ext.length);
@@ -610,9 +615,9 @@ module ts {
         return path;
     }
 
-    var backslashOrDoubleQuote = /[\"\\]/g;
-    var escapedCharsRegExp = /[\u0000-\u001f\t\v\f\b\r\n\u2028\u2029\u0085]/g;
-    var escapedCharsMap: Map<string> = {
+    let backslashOrDoubleQuote = /[\"\\]/g;
+    let escapedCharsRegExp = /[\u0000-\u001f\t\v\f\b\r\n\u2028\u2029\u0085]/g;
+    let escapedCharsMap: Map<string> = {
         "\0": "\\0",
         "\t": "\\t",
         "\v": "\\v",
@@ -651,7 +656,7 @@ module ts {
     function Signature(checker: TypeChecker) {
     }
 
-    export var objectAllocator: ObjectAllocator = {
+    export let objectAllocator: ObjectAllocator = {
         getNodeConstructor: kind => {
             function Node() {
             }
@@ -677,7 +682,7 @@ module ts {
     }
 
     export module Debug {
-        var currentAssertionLevel = AssertionLevel.None;
+        let currentAssertionLevel = AssertionLevel.None;
 
         export function shouldAssert(level: AssertionLevel): boolean {
             return currentAssertionLevel >= level;
@@ -685,7 +690,7 @@ module ts {
 
         export function assert(expression: boolean, message?: string, verboseDebugInfo?: () => string): void {
             if (!expression) {
-                var verboseDebugString = "";
+                let verboseDebugString = "";
                 if (verboseDebugInfo) {
                     verboseDebugString = "\r\nVerbose Debug Information: " + verboseDebugInfo();
                 }

src/compiler/diagnosticInformationMap.generated.ts

@@ -327,7 +327,6 @@ module ts {
         Property_0_does_not_exist_on_const_enum_1: { code: 2479, category: DiagnosticCategory.Error, key: "Property '{0}' does not exist on 'const' enum '{1}'." },
         let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations: { code: 2480, category: DiagnosticCategory.Error, key: "'let' is not allowed to be used as a name in 'let' or 'const' declarations." },
         Cannot_initialize_outer_scoped_variable_0_in_the_same_scope_as_block_scoped_declaration_1: { code: 2481, category: DiagnosticCategory.Error, key: "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'." },
-        for_of_statements_are_only_available_when_targeting_ECMAScript_6_or_higher: { code: 2482, category: DiagnosticCategory.Error, key: "'for...of' statements are only available when targeting ECMAScript 6 or higher." },
         The_left_hand_side_of_a_for_of_statement_cannot_use_a_type_annotation: { code: 2483, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...of' statement cannot use a type annotation." },
         Export_declaration_conflicts_with_exported_declaration_of_0: { code: 2484, category: DiagnosticCategory.Error, key: "Export declaration conflicts with exported declaration of '{0}'" },
         The_left_hand_side_of_a_for_of_statement_cannot_be_a_previously_defined_constant: { code: 2485, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...of' statement cannot be a previously defined constant." },
@@ -338,6 +337,9 @@ module ts {
         The_type_returned_by_the_next_method_of_an_iterator_must_have_a_value_property: { code: 2490, category: DiagnosticCategory.Error, key: "The type returned by the 'next()' method of an iterator must have a 'value' property." },
         The_left_hand_side_of_a_for_in_statement_cannot_be_a_destructuring_pattern: { code: 2491, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...in' statement cannot be a destructuring pattern." },
         Cannot_redeclare_identifier_0_in_catch_clause: { code: 2492, category: DiagnosticCategory.Error, key: "Cannot redeclare identifier '{0}' in catch clause" },
+        Tuple_type_0_with_length_1_cannot_be_assigned_to_tuple_with_length_2: { code: 2493, category: DiagnosticCategory.Error, key: "Tuple type '{0}' with length '{1}' cannot be assigned to tuple with length '{2}'." },
+        Using_a_string_in_a_for_of_statement_is_only_supported_in_ECMAScript_5_and_higher: { code: 2494, category: DiagnosticCategory.Error, key: "Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher." },
+        Type_0_is_not_an_array_type_or_a_string_type: { code: 2461, category: DiagnosticCategory.Error, key: "Type '{0}' is not an array type or a string type." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },

src/compiler/diagnosticMessages.json

@@ -1299,10 +1299,6 @@
         "category": "Error",
         "code": 2481
     },
-    "'for...of' statements are only available when targeting ECMAScript 6 or higher.": {
-        "category": "Error",
-        "code": 2482
-    },
     "The left-hand side of a 'for...of' statement cannot use a type annotation.": {
         "category": "Error",
         "code": 2483
@@ -1343,6 +1339,18 @@
         "category": "Error",
         "code": 2492
     },
+    "Tuple type '{0}' with length '{1}' cannot be assigned to tuple with length '{2}'.": {
+        "category": "Error",
+        "code": 2493
+    },
+    "Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher.": {
+        "category": "Error",
+        "code": 2494
+    },
+    "Type '{0}' is not an array type or a string type.": {
+        "category": "Error",
+        "code": 2461
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/compiler/sys.ts

@@ -124,15 +124,14 @@ module ts {
                 function visitDirectory(path: string) {
                     var folder = fso.GetFolder(path || ".");
                     var files = getNames(folder.files);
-                    for (var i = 0; i < files.length; i++) {
-                        var name = files[i];
+                    for (let name of files) {
                         if (!extension || fileExtensionIs(name, extension)) {
                             result.push(combinePaths(path, name));
                         }
                     }
                     var subfolders = getNames(folder.subfolders);
-                    for (var i = 0; i < subfolders.length; i++) {
-                        visitDirectory(combinePaths(path, subfolders[i]));
+                    for (let current of subfolders) {
+                        visitDirectory(combinePaths(path, current));
                     }
                 }
             }
@@ -230,8 +229,8 @@ module ts {
                 function visitDirectory(path: string) {
                     var files = _fs.readdirSync(path || ".").sort();
                     var directories: string[] = [];
-                    for (var i = 0; i < files.length; i++) {
-                        var name = combinePaths(path, files[i]);
+                    for (let current of files) {
+                        var name = combinePaths(path, current);
                         var stat = _fs.lstatSync(name);
                         if (stat.isFile()) {
                             if (!extension || fileExtensionIs(name, extension)) {
@@ -242,8 +241,8 @@ module ts {
                             directories.push(name);
                         }
                     }
-                    for (var i = 0; i < directories.length; i++) {
-                        visitDirectory(directories[i]);
+                    for (let current of directories) {
+                        visitDirectory(current);
                     }
                 }
             }

src/compiler/types.ts

@@ -233,6 +233,7 @@ module ts {
         EnumDeclaration,
         ModuleDeclaration,
         ModuleBlock,
+        CaseBlock,
         ImportEqualsDeclaration,
         ImportDeclaration,
         ImportClause,
@@ -790,6 +791,10 @@ module ts {
 
     export interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+
+    export interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
 

src/compiler/utilities.ts

@@ -15,8 +15,7 @@ module ts {
 
     export function getDeclarationOfKind(symbol: Symbol, kind: SyntaxKind): Declaration {
         var declarations = symbol.declarations;
-        for (var i = 0; i < declarations.length; i++) {
-            var declaration = declarations[i];
+        for (let declaration of declarations) {
             if (declaration.kind === kind) {
                 return declaration;
             }
@@ -203,6 +202,33 @@ module ts {
             isCatchClauseVariableDeclaration(declaration);
     }
 
+    export function getEnclosingBlockScopeContainer(node: Node): Node {
+        var current = node;
+        while (current) {
+            if (isFunctionLike(current)) {
+                return current;
+            }
+            switch (current.kind) {
+                case SyntaxKind.SourceFile:
+                case SyntaxKind.CaseBlock:
+                case SyntaxKind.CatchClause:
+                case SyntaxKind.ModuleDeclaration:
+                case SyntaxKind.ForStatement:
+                case SyntaxKind.ForInStatement:
+                case SyntaxKind.ForOfStatement:
+                    return current;
+                case SyntaxKind.Block:
+                    // function block is not considered block-scope container
+                    // see comment in binder.ts: bind(...), case for SyntaxKind.Block
+                    if (!isFunctionLike(current.parent)) {
+                        return current;
+                    }
+            }
+
+            current = current.parent;
+        }
+    }
+
     export function isCatchClauseVariableDeclaration(declaration: Declaration) {
         return declaration &&
             declaration.kind === SyntaxKind.VariableDeclaration &&
@@ -376,6 +402,7 @@ module ts {
             switch (node.kind) {
                 case SyntaxKind.ReturnStatement:
                     return visitor(<ReturnStatement>node);
+                case SyntaxKind.CaseBlock:
                 case SyntaxKind.Block:
                 case SyntaxKind.IfStatement:
                 case SyntaxKind.DoStatement:
@@ -824,9 +851,9 @@ module ts {
 
     export function getHeritageClause(clauses: NodeArray<HeritageClause>, kind: SyntaxKind) {
         if (clauses) {
-            for (var i = 0, n = clauses.length; i < n; i++) {
-                if (clauses[i].token === kind) {
-                    return clauses[i];
+            for (let clause of clauses) {
+                if (clause.token === kind) {
+                    return clause;
                 }
             }
         }
@@ -1207,6 +1234,7 @@ module ts {
         }
     }
 
+    // @internal
     export function createDiagnosticCollection(): DiagnosticCollection {
         var nonFileDiagnostics: Diagnostic[] = [];
         var fileDiagnostics: Map<Diagnostic[]> = {};
@@ -1336,4 +1364,4 @@ module ts {
             s.replace(nonAsciiCharacters, c => get16BitUnicodeEscapeSequence(c.charCodeAt(0))) :
             s;
     }
-}
+}

src/lib/core.d.ts

@@ -164,19 +164,19 @@ interface ObjectConstructor {
       * Prevents the modification of attributes of existing properties, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes. 
       */
-    seal(o: any): any;
+    seal<T>(o: T): T;
 
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.
       */
-    freeze(o: any): any;
+    freeze<T>(o: T): T;
 
     /**
       * Prevents the addition of new properties to an object.
       * @param o Object to make non-extensible. 
       */
-    preventExtensions(o: any): any;
+    preventExtensions<T>(o: T): T;
 
     /**
       * Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.

src/services/breakpoints.ts

@@ -13,13 +13,13 @@ module ts.BreakpointResolver {
             return undefined;
         }
 
-        var tokenAtLocation = getTokenAtPosition(sourceFile, position);
-        var lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
+        let tokenAtLocation = getTokenAtPosition(sourceFile, position);
+        let lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
         if (sourceFile.getLineAndCharacterOfPosition(tokenAtLocation.getStart()).line > lineOfPosition) {
             // Get previous token if the token is returned starts on new line
-            // eg: var x =10; |--- cursor is here
-            //     var y = 10; 
-            // token at position will return var keyword on second line as the token but we would like to use 
+            // eg: let x =10; |--- cursor is here
+            //     let y = 10; 
+            // token at position will return let keyword on second line as the token but we would like to use 
             // token on same line if trailing trivia (comments or white spaces on same line) part of the last token on that line
             tokenAtLocation = findPrecedingToken(tokenAtLocation.pos, sourceFile);
 
@@ -275,9 +275,9 @@ module ts.BreakpointResolver {
                     return spanInNode(variableDeclaration.parent.parent);
                 }
 
-                var isParentVariableStatement = variableDeclaration.parent.parent.kind === SyntaxKind.VariableStatement;
-                var isDeclarationOfForStatement = variableDeclaration.parent.parent.kind === SyntaxKind.ForStatement && contains((<VariableDeclarationList>(<ForStatement>variableDeclaration.parent.parent).initializer).declarations, variableDeclaration);
-                var declarations = isParentVariableStatement
+                let isParentVariableStatement = variableDeclaration.parent.parent.kind === SyntaxKind.VariableStatement;
+                let isDeclarationOfForStatement = variableDeclaration.parent.parent.kind === SyntaxKind.ForStatement && contains((<VariableDeclarationList>(<ForStatement>variableDeclaration.parent.parent).initializer).declarations, variableDeclaration);
+                let declarations = isParentVariableStatement
                     ? (<VariableStatement>variableDeclaration.parent.parent).declarationList.declarations
                     : isDeclarationOfForStatement
                         ? (<VariableDeclarationList>(<ForStatement>variableDeclaration.parent.parent).initializer).declarations
@@ -287,12 +287,12 @@ module ts.BreakpointResolver {
                 if (variableDeclaration.initializer || (variableDeclaration.flags & NodeFlags.Export)) {
                     if (declarations && declarations[0] === variableDeclaration) {
                         if (isParentVariableStatement) {
-                            // First declaration - include var keyword
+                            // First declaration - include let keyword
                             return textSpan(variableDeclaration.parent, variableDeclaration);
                         }
                         else {
                             Debug.assert(isDeclarationOfForStatement);
-                            // Include var keyword from for statement declarations in the span
+                            // Include let keyword from for statement declarations in the span
                             return textSpan(findPrecedingToken(variableDeclaration.pos, sourceFile, variableDeclaration.parent), variableDeclaration);
                         }
                     }
@@ -303,7 +303,7 @@ module ts.BreakpointResolver {
                 }
                 else if (declarations && declarations[0] !== variableDeclaration) {
                     // If we cant set breakpoint on this declaration, set it on previous one
-                    var indexOfCurrentDeclaration = indexOf(declarations, variableDeclaration);
+                    let indexOfCurrentDeclaration = indexOf(declarations, variableDeclaration);
                     return spanInVariableDeclaration(declarations[indexOfCurrentDeclaration - 1]);
                 }
             }
@@ -319,8 +319,8 @@ module ts.BreakpointResolver {
                     return textSpan(parameter);
                 }
                 else {
-                    var functionDeclaration = <FunctionLikeDeclaration>parameter.parent;
-                    var indexOfParameter = indexOf(functionDeclaration.parameters, parameter);
+                    let functionDeclaration = <FunctionLikeDeclaration>parameter.parent;
+                    let indexOfParameter = indexOf(functionDeclaration.parameters, parameter);
                     if (indexOfParameter) {
                         // Not a first parameter, go to previous parameter
                         return spanInParameterDeclaration(functionDeclaration.parameters[indexOfParameter - 1]);
@@ -353,7 +353,7 @@ module ts.BreakpointResolver {
             }
 
             function spanInFunctionBlock(block: Block): TextSpan {
-                var nodeForSpanInBlock = block.statements.length ? block.statements[0] : block.getLastToken();
+                let nodeForSpanInBlock = block.statements.length ? block.statements[0] : block.getLastToken();
                 if (canFunctionHaveSpanInWholeDeclaration(<FunctionLikeDeclaration>block.parent)) {
                     return spanInNodeIfStartsOnSameLine(block.parent, nodeForSpanInBlock);
                 }
@@ -387,7 +387,7 @@ module ts.BreakpointResolver {
             function spanInForStatement(forStatement: ForStatement): TextSpan {
                 if (forStatement.initializer) {
                     if (forStatement.initializer.kind === SyntaxKind.VariableDeclarationList) {
-                        var variableDeclarationList = <VariableDeclarationList>forStatement.initializer;
+                        let variableDeclarationList = <VariableDeclarationList>forStatement.initializer;
                         if (variableDeclarationList.declarations.length > 0) {
                             return spanInNode(variableDeclarationList.declarations[0]);
                         }
@@ -409,15 +409,15 @@ module ts.BreakpointResolver {
             function spanInOpenBraceToken(node: Node): TextSpan {
                 switch (node.parent.kind) {
                     case SyntaxKind.EnumDeclaration:
-                        var enumDeclaration = <EnumDeclaration>node.parent;
+                        let enumDeclaration = <EnumDeclaration>node.parent;
                         return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile, node.parent), enumDeclaration.members.length ? enumDeclaration.members[0] : enumDeclaration.getLastToken(sourceFile));
 
                     case SyntaxKind.ClassDeclaration:
-                        var classDeclaration = <ClassDeclaration>node.parent;
+                        let classDeclaration = <ClassDeclaration>node.parent;
                         return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile, node.parent), classDeclaration.members.length ? classDeclaration.members[0] : classDeclaration.getLastToken(sourceFile));
 
-                    case SyntaxKind.SwitchStatement:
-                        return spanInNodeIfStartsOnSameLine(node.parent, (<SwitchStatement>node.parent).clauses[0]);
+                    case SyntaxKind.CaseBlock:
+                        return spanInNodeIfStartsOnSameLine(node.parent.parent, (<CaseBlock>node.parent).clauses[0]);
                 }
 
                 // Default to parent node
@@ -447,10 +447,10 @@ module ts.BreakpointResolver {
                     case SyntaxKind.CatchClause:
                         return spanInNode((<Block>node.parent).statements[(<Block>node.parent).statements.length - 1]);;
 
-                    case SyntaxKind.SwitchStatement:
+                    case SyntaxKind.CaseBlock:
                         // breakpoint in last statement of the last clause
-                        var switchStatement = <SwitchStatement>node.parent;
-                        var lastClause = switchStatement.clauses[switchStatement.clauses.length - 1];
+                        let caseBlock = <CaseBlock>node.parent;
+                        let lastClause = caseBlock.clauses[caseBlock.clauses.length - 1];
                         if (lastClause) {
                             return spanInNode(lastClause.statements[lastClause.statements.length - 1]);
                         }

src/services/formatting/formatting.ts

@@ -609,8 +609,8 @@ module ts.formatting {
                 }
 
                 var inheritedIndentation = Constants.Unknown;
-                for (var i = 0, len = nodes.length; i < len; ++i) {
-                    inheritedIndentation = processChildNode(nodes[i], inheritedIndentation, node, listDynamicIndentation, startLine, /*isListElement*/ true)
+                for (let child of nodes) {
+                    inheritedIndentation = processChildNode(child, inheritedIndentation, node, listDynamicIndentation, startLine, /*isListElement*/ true)
                 }
 
                 if (listEndToken !== SyntaxKind.Unknown) {
@@ -668,8 +668,7 @@ module ts.formatting {
                 if (indentToken) {
                     var indentNextTokenOrTrivia = true;
                     if (currentTokenInfo.leadingTrivia) {
-                        for (var i = 0, len = currentTokenInfo.leadingTrivia.length; i < len; ++i) {
-                            var triviaItem = currentTokenInfo.leadingTrivia[i];
+                        for (let triviaItem of currentTokenInfo.leadingTrivia) {
                             if (!rangeContainsRange(originalRange, triviaItem)) {
                                 continue;
                             }
@@ -709,8 +708,7 @@ module ts.formatting {
         }
 
         function processTrivia(trivia: TextRangeWithKind[], parent: Node, contextNode: Node, dynamicIndentation: DynamicIndentation): void {
-            for (var i = 0, len = trivia.length; i < len; ++i) {
-                var triviaItem = trivia[i];
+            for (let triviaItem of trivia) {
                 if (isComment(triviaItem.kind) && rangeContainsRange(originalRange, triviaItem)) {
                     var triviaItemStart = sourceFile.getLineAndCharacterOfPosition(triviaItem.pos);
                     processRange(triviaItem, triviaItemStart, parent, contextNode, dynamicIndentation);

src/services/formatting/ruleOperationContext.ts

@@ -36,8 +36,8 @@ module ts.formatting {
                 return true;
             }
 
-            for (var i = 0, len = this.customContextChecks.length; i < len; i++) {
-                if (!this.customContextChecks[i](context)) {
+            for (let check of this.customContextChecks) {
+                if (!check(context)) {
                     return false;
                 }
             }

src/services/formatting/rules.ts

@@ -541,7 +541,7 @@ module ts.formatting {
 
             switch (node.kind) {
                 case SyntaxKind.Block:
-                case SyntaxKind.SwitchStatement:
+                case SyntaxKind.CaseBlock:
                 case SyntaxKind.ObjectLiteralExpression:
                 case SyntaxKind.ModuleBlock:
                     return true;

src/services/formatting/rulesMap.ts

@@ -76,10 +76,10 @@ module ts.formatting {
             var bucketIndex = this.GetRuleBucketIndex(context.currentTokenSpan.kind, context.nextTokenSpan.kind);
             var bucket = this.map[bucketIndex];
             if (bucket != null) {
-                for (var i = 0, len = bucket.Rules().length; i < len; i++) {
-                    var rule = bucket.Rules()[i];
-                    if (rule.Operation.Context.InContext(context))
+                for (let rule of bucket.Rules()) {
+                    if (rule.Operation.Context.InContext(context)) {
                         return rule;
+                    }
                 }
             }
             return null;

src/services/formatting/smartIndenter.ts

@@ -357,7 +357,7 @@ module ts.formatting {
                 case SyntaxKind.ModuleBlock:
                 case SyntaxKind.ObjectLiteralExpression:
                 case SyntaxKind.TypeLiteral:
-                case SyntaxKind.SwitchStatement:
+                case SyntaxKind.CaseBlock:
                 case SyntaxKind.DefaultClause:
                 case SyntaxKind.CaseClause:
                 case SyntaxKind.ParenthesizedExpression:
@@ -431,7 +431,7 @@ module ts.formatting {
                 case SyntaxKind.ObjectLiteralExpression:
                 case SyntaxKind.Block:
                 case SyntaxKind.ModuleBlock:
-                case SyntaxKind.SwitchStatement:
+                case SyntaxKind.CaseBlock:
                     return nodeEndsWith(n, SyntaxKind.CloseBraceToken, sourceFile);
                 case SyntaxKind.CatchClause:
                     return isCompletedNode((<CatchClause>n).block, sourceFile);
@@ -461,6 +461,12 @@ module ts.formatting {
                 case SyntaxKind.DefaultClause:
                     // there is no such thing as terminator token for CaseClause\DefaultClause so for simplicitly always consider them non-completed
                     return false;
+                case SyntaxKind.ForStatement:
+                    return isCompletedNode((<ForStatement>n).statement, sourceFile);
+                case SyntaxKind.ForInStatement:
+                    return isCompletedNode((<ForInStatement>n).statement, sourceFile);
+                case SyntaxKind.ForOfStatement:
+                    return isCompletedNode((<ForOfStatement>n).statement, sourceFile);
                 case SyntaxKind.WhileStatement:
                     return isCompletedNode((<WhileStatement>n).statement, sourceFile);
                 case SyntaxKind.DoStatement:

src/services/navigateTo.ts

@@ -2,22 +2,21 @@ module ts.NavigateTo {
     type RawNavigateToItem = { name: string; fileName: string; matchKind: PatternMatchKind; isCaseSensitive: boolean; declaration: Declaration };
 
     export function getNavigateToItems(program: Program, cancellationToken: CancellationTokenObject, searchValue: string, maxResultCount: number): NavigateToItem[] {
-        var patternMatcher = createPatternMatcher(searchValue);
-        var rawItems: RawNavigateToItem[] = [];
+        let patternMatcher = createPatternMatcher(searchValue);
+        let rawItems: RawNavigateToItem[] = [];
 
         // Search the declarations in all files and output matched NavigateToItem into array of NavigateToItem[] 
         forEach(program.getSourceFiles(), sourceFile => {
             cancellationToken.throwIfCancellationRequested();
 
-            var declarations = sourceFile.getNamedDeclarations();
-            for (var i = 0, n = declarations.length; i < n; i++) {
-                var declaration = declarations[i];
+            let declarations = sourceFile.getNamedDeclarations();
+            for (let declaration of declarations) {
                 var name = getDeclarationName(declaration);
                 if (name !== undefined) {
 
                     // First do a quick check to see if the name of the declaration matches the 
                     // last portion of the (possibly) dotted name they're searching for.
-                    var matches = patternMatcher.getMatchesForLastSegmentOfPattern(name);
+                    let matches = patternMatcher.getMatchesForLastSegmentOfPattern(name);
 
                     if (!matches) {
                         continue;
@@ -26,7 +25,7 @@ module ts.NavigateTo {
                     // It was a match!  If the pattern has dots in it, then also see if hte 
                     // declaration container matches as well.
                     if (patternMatcher.patternContainsDots) {
-                        var containers = getContainers(declaration);
+                        let containers = getContainers(declaration);
                         if (!containers) {
                             return undefined;
                         }
@@ -38,8 +37,8 @@ module ts.NavigateTo {
                         }
                     }
 
-                    var fileName = sourceFile.fileName;
-                    var matchKind = bestMatchKind(matches);
+                    let fileName = sourceFile.fileName;
+                    let matchKind = bestMatchKind(matches);
                     rawItems.push({ name, fileName, matchKind, isCaseSensitive: allMatchesAreCaseSensitive(matches), declaration });
                 }
             }
@@ -50,7 +49,7 @@ module ts.NavigateTo {
             rawItems = rawItems.slice(0, maxResultCount);
         }
 
-        var items = map(rawItems, createNavigateToItem);
+        let items = map(rawItems, createNavigateToItem);
 
         return items;
 
@@ -58,8 +57,8 @@ module ts.NavigateTo {
             Debug.assert(matches.length > 0);
 
             // This is a case sensitive match, only if all the submatches were case sensitive.
-            for (var i = 0, n = matches.length; i < n; i++) {
-                if (!matches[i].isCaseSensitive) {
+            for (let match of matches) {
+                if (!match.isCaseSensitive) {
                     return false;
                 }
             }
@@ -68,13 +67,13 @@ module ts.NavigateTo {
         }
 
         function getDeclarationName(declaration: Declaration): string {
-            var result = getTextOfIdentifierOrLiteral(declaration.name);
+            let result = getTextOfIdentifierOrLiteral(declaration.name);
             if (result !== undefined) {
                 return result;
             }
 
             if (declaration.name.kind === SyntaxKind.ComputedPropertyName) {
-                var expr = (<ComputedPropertyName>declaration.name).expression;
+                let expr = (<ComputedPropertyName>declaration.name).expression;
                 if (expr.kind === SyntaxKind.PropertyAccessExpression) {
                     return (<PropertyAccessExpression>expr).name.text;
                 }
@@ -98,7 +97,7 @@ module ts.NavigateTo {
 
         function tryAddSingleDeclarationName(declaration: Declaration, containers: string[]) {
             if (declaration && declaration.name) {
-                var text = getTextOfIdentifierOrLiteral(declaration.name);
+                let text = getTextOfIdentifierOrLiteral(declaration.name);
                 if (text !== undefined) {
                     containers.unshift(text);
                 }
@@ -118,7 +117,7 @@ module ts.NavigateTo {
         //
         //      [X.Y.Z]() { }
         function tryAddComputedPropertyName(expression: Expression, containers: string[], includeLastPortion: boolean): boolean {
-            var text = getTextOfIdentifierOrLiteral(expression);
+            let text = getTextOfIdentifierOrLiteral(expression);
             if (text !== undefined) {
                 if (includeLastPortion) {
                     containers.unshift(text);
@@ -127,7 +126,7 @@ module ts.NavigateTo {
             }
 
             if (expression.kind === SyntaxKind.PropertyAccessExpression) {
-                var propertyAccess = <PropertyAccessExpression>expression;
+                let propertyAccess = <PropertyAccessExpression>expression;
                 if (includeLastPortion) {
                     containers.unshift(propertyAccess.name.text);
                 }
@@ -139,7 +138,7 @@ module ts.NavigateTo {
         }
 
         function getContainers(declaration: Declaration) {
-            var containers: string[] = [];
+            let containers: string[] = [];
 
             // First, if we started with a computed property name, then add all but the last
             // portion into the container array.
@@ -165,10 +164,10 @@ module ts.NavigateTo {
 
         function bestMatchKind(matches: PatternMatch[]) {
             Debug.assert(matches.length > 0);
-            var bestMatchKind = PatternMatchKind.camelCase;
+            let bestMatchKind = PatternMatchKind.camelCase;
 
-            for (var i = 0, n = matches.length; i < n; i++) {
-                var kind = matches[i].kind;
+            for (let match of matches) {
+                let kind = match.kind;
                 if (kind < bestMatchKind) {
                     bestMatchKind = kind;
                 }
@@ -178,7 +177,7 @@ module ts.NavigateTo {
         }
 
         // This means "compare in a case insensitive manner."
-        var baseSensitivity: Intl.CollatorOptions = { sensitivity: "base" };
+        let baseSensitivity: Intl.CollatorOptions = { sensitivity: "base" };
         function compareNavigateToItems(i1: RawNavigateToItem, i2: RawNavigateToItem) {
             // TODO(cyrusn): get the gamut of comparisons that VS already uses here.
             // Right now we just sort by kind first, and then by name of the item.
@@ -190,8 +189,8 @@ module ts.NavigateTo {
         }
 
         function createNavigateToItem(rawItem: RawNavigateToItem): NavigateToItem {
-            var declaration = rawItem.declaration;
-            var container = <Declaration>getContainerNode(declaration);
+            let declaration = rawItem.declaration;
+            let container = <Declaration>getContainerNode(declaration);
             return {
                 name: rawItem.name,
                 kind: getNodeKind(declaration),

src/services/navigationBar.ts

@@ -4,16 +4,16 @@ module ts.NavigationBar {
     export function getNavigationBarItems(sourceFile: SourceFile): ts.NavigationBarItem[]  {
         // If the source file has any child items, then it included in the tree
         // and takes lexical ownership of all other top-level items.
-        var hasGlobalNode = false;
+        let hasGlobalNode = false;
 
         return getItemsWorker(getTopLevelNodes(sourceFile), createTopLevelItem);
 
         function getIndent(node: Node): number {
             // If we have a global node in the tree,
             // then it adds an extra layer of depth to all subnodes.
-            var indent = hasGlobalNode ? 1 : 0;
+            let indent = hasGlobalNode ? 1 : 0;
 
-            var current = node.parent;
+            let current = node.parent;
             while (current) {
                 switch (current.kind) {
                     case SyntaxKind.ModuleDeclaration:
@@ -39,7 +39,7 @@ module ts.NavigationBar {
         }
 
         function getChildNodes(nodes: Node[]): Node[] {
-            var childNodes: Node[] = [];
+            let childNodes: Node[] = [];
 
             function visit(node: Node) {
                 switch (node.kind) {
@@ -60,7 +60,7 @@ module ts.NavigationBar {
                         break;
 
                     case SyntaxKind.ImportDeclaration:
-                        var importClause = (<ImportDeclaration>node).importClause;
+                        let importClause = (<ImportDeclaration>node).importClause;
                         if (importClause) {
                             // Handle default import case e.g.:
                             //    import d from "mod";
@@ -102,8 +102,8 @@ module ts.NavigationBar {
                 }
             }
 
-            //for (var i = 0, n = nodes.length; i < n; i++) {
-            //    var node = nodes[i];
+            //for (let i = 0, n = nodes.length; i < n; i++) {
+            //    let node = nodes[i];
 
             //    if (node.kind === SyntaxKind.ClassDeclaration ||
             //        node.kind === SyntaxKind.EnumDeclaration ||
@@ -122,7 +122,7 @@ module ts.NavigationBar {
         }
 
         function getTopLevelNodes(node: SourceFile): Node[] {
-            var topLevelNodes: Node[] = [];
+            let topLevelNodes: Node[] = [];
             topLevelNodes.push(node);
 
             addTopLevelNodes(node.statements, topLevelNodes);
@@ -150,8 +150,7 @@ module ts.NavigationBar {
         function addTopLevelNodes(nodes: Node[], topLevelNodes: Node[]): void {
             nodes = sortNodes(nodes);
 
-            for (var i = 0, n = nodes.length; i < n; i++) {
-                var node = nodes[i];
+            for (let node of nodes) {
                 switch (node.kind) {
                     case SyntaxKind.ClassDeclaration:
                     case SyntaxKind.EnumDeclaration:
@@ -160,13 +159,13 @@ module ts.NavigationBar {
                         break;
 
                     case SyntaxKind.ModuleDeclaration:
-                        var moduleDeclaration = <ModuleDeclaration>node;
+                        let moduleDeclaration = <ModuleDeclaration>node;
                         topLevelNodes.push(node);
                         addTopLevelNodes((<Block>getInnermostModule(moduleDeclaration).body).statements, topLevelNodes);
                         break;
 
                     case SyntaxKind.FunctionDeclaration:
-                        var functionDeclaration = <FunctionLikeDeclaration>node;
+                        let functionDeclaration = <FunctionLikeDeclaration>node;
                         if (isTopLevelFunctionDeclaration(functionDeclaration)) {
                             topLevelNodes.push(node);
                             addTopLevelNodes((<Block>functionDeclaration.body).statements, topLevelNodes);
@@ -200,18 +199,17 @@ module ts.NavigationBar {
         }
         
         function getItemsWorker(nodes: Node[], createItem: (n: Node) => ts.NavigationBarItem): ts.NavigationBarItem[] {
-            var items: ts.NavigationBarItem[] = [];
+            let items: ts.NavigationBarItem[] = [];
 
-            var keyToItem: Map<NavigationBarItem> = {};
+            let keyToItem: Map<NavigationBarItem> = {};
 
-            for (var i = 0, n = nodes.length; i < n; i++) {
-                var child = nodes[i];
-                var item = createItem(child);
+            for (let child of nodes) {
+                let item = createItem(child);
                 if (item !== undefined) {
                     if (item.text.length > 0) {
-                        var key = item.text + "-" + item.kind + "-" + item.indent;
+                        let key = item.text + "-" + item.kind + "-" + item.indent;
 
-                        var itemWithSameName = keyToItem[key];
+                        let itemWithSameName = keyToItem[key];
                         if (itemWithSameName) {
                             // We had an item with the same name.  Merge these items together.
                             merge(itemWithSameName, item);
@@ -238,12 +236,8 @@ module ts.NavigationBar {
 
                 // Next, recursively merge or add any children in the source as appropriate.
                 outer:
-                for (var i = 0, n = source.childItems.length; i < n; i++) {
-                    var sourceChild = source.childItems[i];
-
-                    for (var j = 0, m = target.childItems.length; j < m; j++) {
-                        var targetChild = target.childItems[j];
-
+                for (let sourceChild of source.childItems) {
+                    for (let targetChild of target.childItems) {
                         if (targetChild.text === sourceChild.text && targetChild.kind === sourceChild.kind) {
                             // Found a match.  merge them.
                             merge(targetChild, sourceChild);
@@ -299,8 +293,8 @@ module ts.NavigationBar {
 
                 case SyntaxKind.VariableDeclaration:
                 case SyntaxKind.BindingElement:
-                    var variableDeclarationNode: Node;
-                    var name: Node;
+                    let variableDeclarationNode: Node;
+                    let name: Node;
 
                     if (node.kind === SyntaxKind.BindingElement) {
                         name = (<BindingElement>node).name;
@@ -397,7 +391,7 @@ module ts.NavigationBar {
                 }
 
                 // Otherwise, we need to aggregate each identifier to build up the qualified name.
-                var result: string[] = [];
+                let result: string[] = [];
 
                 result.push(moduleDeclaration.name.text);
                 
@@ -411,9 +405,9 @@ module ts.NavigationBar {
             }
 
             function createModuleItem(node: ModuleDeclaration): NavigationBarItem {
-                var moduleName = getModuleName(node);
+                let moduleName = getModuleName(node);
                 
-                var childItems = getItemsWorker(getChildNodes((<Block>getInnermostModule(node).body).statements), createChildItem);
+                let childItems = getItemsWorker(getChildNodes((<Block>getInnermostModule(node).body).statements), createChildItem);
 
                 return getNavigationBarItem(moduleName,
                     ts.ScriptElementKind.moduleElement,
@@ -425,7 +419,7 @@ module ts.NavigationBar {
 
             function createFunctionItem(node: FunctionDeclaration) {
                 if (node.name && node.body && node.body.kind === SyntaxKind.Block) {
-                    var childItems = getItemsWorker(sortNodes((<Block>node.body).statements), createChildItem);
+                    let childItems = getItemsWorker(sortNodes((<Block>node.body).statements), createChildItem);
 
                     return getNavigationBarItem(node.name.text,
                         ts.ScriptElementKind.functionElement,
@@ -439,14 +433,14 @@ module ts.NavigationBar {
             }
 
             function createSourceFileItem(node: SourceFile): ts.NavigationBarItem {
-                var childItems = getItemsWorker(getChildNodes(node.statements), createChildItem);
+                let childItems = getItemsWorker(getChildNodes(node.statements), createChildItem);
 
                 if (childItems === undefined || childItems.length === 0) {
                     return undefined;
                 }
 
                 hasGlobalNode = true;
-                var rootName = isExternalModule(node)
+                let rootName = isExternalModule(node)
                     ? "\"" + escapeString(getBaseFileName(removeFileExtension(normalizePath(node.fileName)))) + "\""
                     : "<global>"
 
@@ -463,22 +457,22 @@ module ts.NavigationBar {
                     return undefined;
                 }
 
-                var childItems: NavigationBarItem[];
+                let childItems: NavigationBarItem[];
 
                 if (node.members) {
-                    var constructor = <ConstructorDeclaration>forEach(node.members, member => {
+                    let constructor = <ConstructorDeclaration>forEach(node.members, member => {
                         return member.kind === SyntaxKind.Constructor && member;
                     });
 
                     // Add the constructor parameters in as children of the class (for property parameters).
                     // Note that *all non-binding pattern named* parameters will be added to the nodes array, but parameters that
                     // are not properties will be filtered out later by createChildItem.
-                    var nodes: Node[] = removeDynamicallyNamedProperties(node);
+                    let nodes: Node[] = removeDynamicallyNamedProperties(node);
                     if (constructor) {
                         nodes.push.apply(nodes, filter(constructor.parameters, p => !isBindingPattern(p.name)));
                     }
 
-                    var childItems = getItemsWorker(sortNodes(nodes), createChildItem);
+                    childItems = getItemsWorker(sortNodes(nodes), createChildItem);
                 }
 
                 return getNavigationBarItem(
@@ -491,7 +485,7 @@ module ts.NavigationBar {
             }
 
             function createEnumItem(node: EnumDeclaration): ts.NavigationBarItem {
-                var childItems = getItemsWorker(sortNodes(removeComputedProperties(node)), createChildItem);
+                let childItems = getItemsWorker(sortNodes(removeComputedProperties(node)), createChildItem);
                 return getNavigationBarItem(
                     node.name.text,
                     ts.ScriptElementKind.enumElement,
@@ -502,7 +496,7 @@ module ts.NavigationBar {
             }
 
             function createIterfaceItem(node: InterfaceDeclaration): ts.NavigationBarItem {
-                var childItems = getItemsWorker(sortNodes(removeDynamicallyNamedProperties(node)), createChildItem);
+                let childItems = getItemsWorker(sortNodes(removeDynamicallyNamedProperties(node)), createChildItem);
                 return getNavigationBarItem(
                     node.name.text,
                     ts.ScriptElementKind.interfaceElement,

src/services/outliningElementsCollector.ts

@@ -16,12 +16,12 @@
 module ts {
     export module OutliningElementsCollector {
         export function collectElements(sourceFile: SourceFile): OutliningSpan[] {
-            var elements: OutliningSpan[] = [];
-            var collapseText = "...";
+            let elements: OutliningSpan[] = [];
+            let collapseText = "...";
 
             function addOutliningSpan(hintSpanNode: Node, startElement: Node, endElement: Node, autoCollapse: boolean) {
                 if (hintSpanNode && startElement && endElement) {
-                    var span: OutliningSpan = {
+                    let span: OutliningSpan = {
                         textSpan: createTextSpanFromBounds(startElement.pos, endElement.end),
                         hintSpan: createTextSpanFromBounds(hintSpanNode.getStart(), hintSpanNode.end),
                         bannerText: collapseText,
@@ -35,8 +35,8 @@ module ts {
                 return isFunctionBlock(node) && node.parent.kind !== SyntaxKind.ArrowFunction;
             }
 
-            var depth = 0;
-            var maxDepth = 20;
+            let depth = 0;
+            let maxDepth = 20;
             function walk(n: Node): void {
                 if (depth > maxDepth) {
                     return;
@@ -44,9 +44,9 @@ module ts {
                 switch (n.kind) {
                     case SyntaxKind.Block:
                         if (!isFunctionBlock(n)) {
-                            var parent = n.parent;
-                            var openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
-                            var closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
+                            let parent = n.parent;
+                            let openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
+                            let closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
 
                             // Check if the block is standalone, or 'attached' to some parent statement.
                             // If the latter, we want to collaps the block, but consider its hint span
@@ -66,13 +66,13 @@ module ts {
 
                             if (parent.kind === SyntaxKind.TryStatement) {
                                 // Could be the try-block, or the finally-block.
-                                var tryStatement = <TryStatement>parent;
+                                let tryStatement = <TryStatement>parent;
                                 if (tryStatement.tryBlock === n) {
                                     addOutliningSpan(parent, openBrace, closeBrace, autoCollapse(n));
                                     break;
                                 }
                                 else if (tryStatement.finallyBlock === n) {
-                                    var finallyKeyword = findChildOfKind(tryStatement, SyntaxKind.FinallyKeyword, sourceFile);
+                                    let finallyKeyword = findChildOfKind(tryStatement, SyntaxKind.FinallyKeyword, sourceFile);
                                     if (finallyKeyword) {
                                         addOutliningSpan(finallyKeyword, openBrace, closeBrace, autoCollapse(n));
                                         break;
@@ -84,7 +84,7 @@ module ts {
 
                             // Block was a standalone block.  In this case we want to only collapse
                             // the span of the block, independent of any parent span.
-                            var span = createTextSpanFromBounds(n.getStart(), n.end);
+                            let span = createTextSpanFromBounds(n.getStart(), n.end);
                             elements.push({
                                 textSpan: span,
                                 hintSpan: span,
@@ -95,23 +95,25 @@ module ts {
                         }
                         // Fallthrough.
 
-                    case SyntaxKind.ModuleBlock:
-                        var openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
-                        var closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
+                    case SyntaxKind.ModuleBlock: {
+                        let openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
+                        let closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
                         addOutliningSpan(n.parent, openBrace, closeBrace, autoCollapse(n));
                         break;
+                    }
                     case SyntaxKind.ClassDeclaration:
                     case SyntaxKind.InterfaceDeclaration:
                     case SyntaxKind.EnumDeclaration:
                     case SyntaxKind.ObjectLiteralExpression:
-                    case SyntaxKind.SwitchStatement:
-                        var openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
-                        var closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
+                    case SyntaxKind.CaseBlock: {
+                        let openBrace = findChildOfKind(n, SyntaxKind.OpenBraceToken, sourceFile);
+                        let closeBrace = findChildOfKind(n, SyntaxKind.CloseBraceToken, sourceFile);
                         addOutliningSpan(n, openBrace, closeBrace, autoCollapse(n));
                         break;
+                    }
                     case SyntaxKind.ArrayLiteralExpression:
-                        var openBracket = findChildOfKind(n, SyntaxKind.OpenBracketToken, sourceFile);
-                        var closeBracket = findChildOfKind(n, SyntaxKind.CloseBracketToken, sourceFile);
+                        let openBracket = findChildOfKind(n, SyntaxKind.OpenBracketToken, sourceFile);
+                        let closeBracket = findChildOfKind(n, SyntaxKind.CloseBracketToken, sourceFile);
                         addOutliningSpan(n, openBracket, closeBracket, autoCollapse(n));
                         break;
                 }

src/services/patternMatcher.ts

@@ -112,13 +112,13 @@ module ts {
         // we see the name of a module that is used everywhere, or the name of an overload).  As 
         // such, we cache the information we compute about the candidate for the life of this 
         // pattern matcher so we don't have to compute it multiple times.
-        var stringToWordSpans: Map<TextSpan[]> = {};
+        let stringToWordSpans: Map<TextSpan[]> = {};
 
         pattern = pattern.trim();
 
-        var fullPatternSegment = createSegment(pattern);
-        var dotSeparatedSegments = pattern.split(".").map(p => createSegment(p.trim()));
-        var invalidPattern = dotSeparatedSegments.length === 0 || forEach(dotSeparatedSegments, segmentIsInvalid);
+        let fullPatternSegment = createSegment(pattern);
+        let dotSeparatedSegments = pattern.split(".").map(p => createSegment(p.trim()));
+        let invalidPattern = dotSeparatedSegments.length === 0 || forEach(dotSeparatedSegments, segmentIsInvalid);
 
         return {
             getMatches,
@@ -147,7 +147,7 @@ module ts {
             // First, check that the last part of the dot separated pattern matches the name of the
             // candidate.  If not, then there's no point in proceeding and doing the more
             // expensive work.
-            var candidateMatch = matchSegment(candidate, lastOrUndefined(dotSeparatedSegments));
+            let candidateMatch = matchSegment(candidate, lastOrUndefined(dotSeparatedSegments));
             if (!candidateMatch) {
                 return undefined;
             }
@@ -164,16 +164,16 @@ module ts {
 
             // So far so good.  Now break up the container for the candidate and check if all
             // the dotted parts match up correctly.
-            var totalMatch = candidateMatch;
+            let totalMatch = candidateMatch;
 
-            for (var i = dotSeparatedSegments.length - 2, j = candidateContainers.length - 1;
+            for (let i = dotSeparatedSegments.length - 2, j = candidateContainers.length - 1;
                  i >= 0;
                  i--, j--) {
 
-                var segment = dotSeparatedSegments[i];
-                var containerName = candidateContainers[j];
+                let segment = dotSeparatedSegments[i];
+                let containerName = candidateContainers[j];
 
-                var containerMatch = matchSegment(containerName, segment);
+                let containerMatch = matchSegment(containerName, segment);
                 if (!containerMatch) {
                     // This container didn't match the pattern piece.  So there's no match at all.
                     return undefined;
@@ -196,7 +196,7 @@ module ts {
         }
 
         function matchTextChunk(candidate: string, chunk: TextChunk, punctuationStripped: boolean): PatternMatch {
-            var index = indexOfIgnoringCase(candidate, chunk.textLowerCase);
+            let index = indexOfIgnoringCase(candidate, chunk.textLowerCase);
             if (index === 0) {
                 if (chunk.text.length === candidate.length) {
                     // a) Check if the part matches the candidate entirely, in an case insensitive or
@@ -210,7 +210,7 @@ module ts {
                 }
             }
 
-            var isLowercase = chunk.isLowerCase;
+            let isLowercase = chunk.isLowerCase;
             if (isLowercase) {
                 if (index > 0) {
                     // c) If the part is entirely lowercase, then check if it is contained anywhere in the
@@ -220,9 +220,8 @@ module ts {
                     //    Note: We only have a substring match if the lowercase part is prefix match of some
                     //    word part. That way we don't match something like 'Class' when the user types 'a'.
                     //    But we would match 'FooAttribute' (since 'Attribute' starts with 'a').
-                    var wordSpans = getWordSpans(candidate);
-                    for (var i = 0, n = wordSpans.length; i < n; i++) {
-                        var span = wordSpans[i]
+                    let wordSpans = getWordSpans(candidate);
+                    for (let span of wordSpans) {
                         if (partStartsWith(candidate, span, chunk.text, /*ignoreCase:*/ true)) {
                             return createPatternMatch(PatternMatchKind.substring, punctuationStripped,
                                 /*isCaseSensitive:*/ partStartsWith(candidate, span, chunk.text, /*ignoreCase:*/ false));
@@ -242,8 +241,8 @@ module ts {
             if (!isLowercase) {
                 // e) If the part was not entirely lowercase, then attempt a camel cased match as well.
                 if (chunk.characterSpans.length > 0) {
-                    var candidateParts = getWordSpans(candidate);
-                    var camelCaseWeight = tryCamelCaseMatch(candidate, candidateParts, chunk, /*ignoreCase:*/ false);
+                    let candidateParts = getWordSpans(candidate);
+                    let camelCaseWeight = tryCamelCaseMatch(candidate, candidateParts, chunk, /*ignoreCase:*/ false);
                     if (camelCaseWeight !== undefined) {
                         return createPatternMatch(PatternMatchKind.camelCase, punctuationStripped, /*isCaseSensitive:*/ true, /*camelCaseWeight:*/ camelCaseWeight);
                     }
@@ -274,8 +273,8 @@ module ts {
         }
 
         function containsSpaceOrAsterisk(text: string): boolean {
-            for (var i = 0; i < text.length; i++) {
-                var ch = text.charCodeAt(i);
+            for (let i = 0; i < text.length; i++) {
+                let ch = text.charCodeAt(i);
                 if (ch === CharacterCodes.space || ch === CharacterCodes.asterisk) {
                     return true;
                 }
@@ -293,7 +292,7 @@ module ts {
             // Note: if the segment contains a space or an asterisk then we must assume that it's a
             // multi-word segment.
             if (!containsSpaceOrAsterisk(segment.totalTextChunk.text)) {
-                var match = matchTextChunk(candidate, segment.totalTextChunk, /*punctuationStripped:*/ false);
+                let match = matchTextChunk(candidate, segment.totalTextChunk, /*punctuationStripped:*/ false);
                 if (match) {
                     return [match];
                 }
@@ -336,14 +335,12 @@ module ts {
             //
             // Only if all words have some sort of match is the pattern considered matched.
 
-            var subWordTextChunks = segment.subWordTextChunks;
-            var matches: PatternMatch[] = undefined;
-
-            for (var i = 0, n = subWordTextChunks.length; i < n; i++) {
-                var subWordTextChunk = subWordTextChunks[i];
+            let subWordTextChunks = segment.subWordTextChunks;
+            let matches: PatternMatch[] = undefined;
 
+            for (let subWordTextChunk of subWordTextChunks) {
                 // Try to match the candidate with this word
-                var result = matchTextChunk(candidate, subWordTextChunk, /*punctuationStripped:*/ true);
+                let result = matchTextChunk(candidate, subWordTextChunk, /*punctuationStripped:*/ true);
                 if (!result) {
                     return undefined;
                 }
@@ -356,8 +353,8 @@ module ts {
         }
 
         function partStartsWith(candidate: string, candidateSpan: TextSpan, pattern: string, ignoreCase: boolean, patternSpan?: TextSpan): boolean {
-            var patternPartStart = patternSpan ? patternSpan.start : 0;
-            var patternPartLength = patternSpan ? patternSpan.length : pattern.length;
+            let patternPartStart = patternSpan ? patternSpan.start : 0;
+            let patternPartLength = patternSpan ? patternSpan.length : pattern.length;
 
             if (patternPartLength > candidateSpan.length) {
                 // Pattern part is longer than the candidate part. There can never be a match.
@@ -365,18 +362,18 @@ module ts {
             }
             
             if (ignoreCase) {
-                for (var i = 0; i < patternPartLength; i++) {
-                    var ch1 = pattern.charCodeAt(patternPartStart + i);
-                    var ch2 = candidate.charCodeAt(candidateSpan.start + i);
+                for (let i = 0; i < patternPartLength; i++) {
+                    let ch1 = pattern.charCodeAt(patternPartStart + i);
+                    let ch2 = candidate.charCodeAt(candidateSpan.start + i);
                     if (toLowerCase(ch1) !== toLowerCase(ch2)) {
                         return false;
                     }
                 }
             }
             else {
-                for (var i = 0; i < patternPartLength; i++) {
-                    var ch1 = pattern.charCodeAt(patternPartStart + i);
-                    var ch2 = candidate.charCodeAt(candidateSpan.start + i);
+                for (let i = 0; i < patternPartLength; i++) {
+                    let ch1 = pattern.charCodeAt(patternPartStart + i);
+                    let ch2 = candidate.charCodeAt(candidateSpan.start + i);
                     if (ch1 !== ch2) {
                         return false;
                     }
@@ -387,23 +384,23 @@ module ts {
         }
 
         function tryCamelCaseMatch(candidate: string, candidateParts: TextSpan[], chunk: TextChunk, ignoreCase: boolean): number {
-            var chunkCharacterSpans = chunk.characterSpans;
+            let chunkCharacterSpans = chunk.characterSpans;
 
             // Note: we may have more pattern parts than candidate parts.  This is because multiple
             // pattern parts may match a candidate part.  For example "SiUI" against "SimpleUI".
             // We'll have 3 pattern parts Si/U/I against two candidate parts Simple/UI.  However, U
             // and I will both match in UI. 
 
-            var currentCandidate = 0;
-            var currentChunkSpan = 0;
-            var firstMatch: number = undefined;
-            var contiguous: boolean = undefined;
+            let currentCandidate = 0;
+            let currentChunkSpan = 0;
+            let firstMatch: number = undefined;
+            let contiguous: boolean = undefined;
 
             while (true) {
                 // Let's consider our termination cases
                 if (currentChunkSpan === chunkCharacterSpans.length) {
                     // We did match! We shall assign a weight to this
-                    var weight = 0;
+                    let weight = 0;
 
                     // Was this contiguous?
                     if (contiguous) {
@@ -422,15 +419,15 @@ module ts {
                     return undefined;
                 }
 
-                var candidatePart = candidateParts[currentCandidate];
-                var gotOneMatchThisCandidate = false;
+                let candidatePart = candidateParts[currentCandidate];
+                let gotOneMatchThisCandidate = false;
 
                 // Consider the case of matching SiUI against SimpleUIElement. The candidate parts
                 // will be Simple/UI/Element, and the pattern parts will be Si/U/I.  We'll match 'Si'
                 // against 'Simple' first.  Then we'll match 'U' against 'UI'. However, we want to
                 // still keep matching pattern parts against that candidate part. 
                 for (; currentChunkSpan < chunkCharacterSpans.length; currentChunkSpan++) {
-                    var chunkCharacterSpan = chunkCharacterSpans[currentChunkSpan];
+                    let chunkCharacterSpan = chunkCharacterSpans[currentChunkSpan];
 
                     if (gotOneMatchThisCandidate) {
                         // We've already gotten one pattern part match in this candidate.  We will
@@ -540,7 +537,7 @@ module ts {
 
         // TODO: find a way to determine this for any unicode characters in a 
         // non-allocating manner.
-        var str = String.fromCharCode(ch);
+        let str = String.fromCharCode(ch);
         return str === str.toUpperCase();
     }
 
@@ -557,12 +554,12 @@ module ts {
 
         // TODO: find a way to determine this for any unicode characters in a 
         // non-allocating manner.
-        var str = String.fromCharCode(ch);
+        let str = String.fromCharCode(ch);
         return str === str.toLowerCase();
     }
 
     function containsUpperCaseLetter(string: string): boolean {
-        for (var i = 0, n = string.length; i < n; i++) {
+        for (let i = 0, n = string.length; i < n; i++) {
             if (isUpperCaseLetter(string.charCodeAt(i))) {
                 return true;
             }
@@ -572,7 +569,7 @@ module ts {
     }
 
     function startsWith(string: string, search: string) {
-        for (var i = 0, n = search.length; i < n; i++) {
+        for (let i = 0, n = search.length; i < n; i++) {
             if (string.charCodeAt(i) !== search.charCodeAt(i)) {
                 return false;
             }
@@ -583,7 +580,7 @@ module ts {
 
     // Assumes 'value' is already lowercase.
     function indexOfIgnoringCase(string: string, value: string): number {
-        for (var i = 0, n = string.length - value.length; i <= n; i++) {
+        for (let i = 0, n = string.length - value.length; i <= n; i++) {
             if (startsWithIgnoringCase(string, value, i)) {
                 return i;
             }
@@ -594,9 +591,9 @@ module ts {
 
     // Assumes 'value' is already lowercase.
     function startsWithIgnoringCase(string: string, value: string, start: number): boolean {
-        for (var i = 0, n = value.length; i < n; i++) {
-            var ch1 = toLowerCase(string.charCodeAt(i + start));
-            var ch2 = value.charCodeAt(i);
+        for (let i = 0, n = value.length; i < n; i++) {
+            let ch1 = toLowerCase(string.charCodeAt(i + start));
+            let ch2 = value.charCodeAt(i);
 
             if (ch1 !== ch2) {
                 return false;
@@ -631,12 +628,12 @@ module ts {
     }
 
     function breakPatternIntoTextChunks(pattern: string): TextChunk[] {
-        var result: TextChunk[] = [];
-        var wordStart = 0;
-        var wordLength = 0;
+        let result: TextChunk[] = [];
+        let wordStart = 0;
+        let wordLength = 0;
 
-        for (var i = 0; i < pattern.length; i++) {
-            var ch = pattern.charCodeAt(i);
+        for (let i = 0; i < pattern.length; i++) {
+            let ch = pattern.charCodeAt(i);
             if (isWordChar(ch)) {
                 if (wordLength++ === 0) {
                     wordStart = i;
@@ -658,7 +655,7 @@ module ts {
     }
 
     function createTextChunk(text: string): TextChunk {
-        var textLowerCase = text.toLowerCase();
+        let textLowerCase = text.toLowerCase();
         return {
             text,
             textLowerCase,
@@ -676,15 +673,15 @@ module ts {
     }
 
     function breakIntoSpans(identifier: string, word: boolean): TextSpan[] {
-        var result: TextSpan[] = [];
+        let result: TextSpan[] = [];
 
-        var wordStart = 0;
-        for (var i = 1, n = identifier.length; i < n; i++) {
-            var lastIsDigit = isDigit(identifier.charCodeAt(i - 1));
-            var currentIsDigit = isDigit(identifier.charCodeAt(i));
+        let wordStart = 0;
+        for (let i = 1, n = identifier.length; i < n; i++) {
+            let lastIsDigit = isDigit(identifier.charCodeAt(i - 1));
+            let currentIsDigit = isDigit(identifier.charCodeAt(i));
 
-            var hasTransitionFromLowerToUpper = transitionFromLowerToUpper(identifier, word, i);
-            var hasTransitionFromUpperToLower = transitionFromUpperToLower(identifier, word, i, wordStart);
+            let hasTransitionFromLowerToUpper = transitionFromLowerToUpper(identifier, word, i);
+            let hasTransitionFromUpperToLower = transitionFromUpperToLower(identifier, word, i, wordStart);
 
             if (charIsPunctuation(identifier.charCodeAt(i - 1)) ||
                 charIsPunctuation(identifier.charCodeAt(i)) ||
@@ -739,8 +736,8 @@ module ts {
     }
 
     function isAllPunctuation(identifier: string, start: number, end: number): boolean {
-        for (var i = start; i < end; i++) {
-            var ch = identifier.charCodeAt(i);
+        for (let i = start; i < end; i++) {
+            let ch = identifier.charCodeAt(i);
 
             // We don't consider _ or $ as punctuation as there may be things with that name.
             if (!charIsPunctuation(ch) || ch === CharacterCodes._ || ch === CharacterCodes.$) {
@@ -761,8 +758,8 @@ module ts {
             // etc.
             if (index != wordStart &&
                 index + 1 < identifier.length) {
-                var currentIsUpper = isUpperCaseLetter(identifier.charCodeAt(index));
-                var nextIsLower = isLowerCaseLetter(identifier.charCodeAt(index + 1));
+                let currentIsUpper = isUpperCaseLetter(identifier.charCodeAt(index));
+                let nextIsLower = isLowerCaseLetter(identifier.charCodeAt(index + 1));
 
                 if (currentIsUpper && nextIsLower) {
                     // We have a transition from an upper to a lower letter here.  But we only
@@ -773,7 +770,7 @@ module ts {
                     // that follows.  Note: this will make the following not split properly:
                     // "HELLOthere".  However, these sorts of names do not show up in .Net
                     // programs.
-                    for (var i = wordStart; i < index; i++) {
+                    for (let i = wordStart; i < index; i++) {
                         if (!isUpperCaseLetter(identifier.charCodeAt(i))) {
                             return false;
                         }
@@ -788,8 +785,8 @@ module ts {
     }
 
     function transitionFromLowerToUpper(identifier: string, word: boolean, index: number): boolean {
-        var lastIsUpper = isUpperCaseLetter(identifier.charCodeAt(index - 1));
-        var currentIsUpper = isUpperCaseLetter(identifier.charCodeAt(index));
+        let lastIsUpper = isUpperCaseLetter(identifier.charCodeAt(index - 1));
+        let currentIsUpper = isUpperCaseLetter(identifier.charCodeAt(index));
 
         // See if the casing indicates we're starting a new word. Note: if we're breaking on
         // words, then just seeing an upper case character isn't enough.  Instead, it has to
@@ -804,7 +801,7 @@ module ts {
         // on characters would be: A M
         //
         // We break the search string on characters.  But we break the symbol name on words.
-        var transition = word
+        let transition = word
             ? (currentIsUpper && !lastIsUpper)
             : currentIsUpper;
         return transition;

src/services/signatureHelp.ts

@@ -8,15 +8,15 @@ module ts.SignatureHelp {
     // will return the generic identifier that started the expression (e.g. "foo" in "foo<any, |"). It is then up to the caller to ensure that this is a valid generic expression through 
     // looking up the type. The method will also keep track of the parameter index inside the expression.
     //public static isInPartiallyWrittenTypeArgumentList(syntaxTree: TypeScript.SyntaxTree, position: number): any {
-    //    var token = Syntax.findTokenOnLeft(syntaxTree.sourceUnit(), position, /*includeSkippedTokens*/ true);
+    //    let token = Syntax.findTokenOnLeft(syntaxTree.sourceUnit(), position, /*includeSkippedTokens*/ true);
 
     //    if (token && TypeScript.Syntax.hasAncestorOfKind(token, TypeScript.SyntaxKind.TypeParameterList)) {
     //        // We are in the wrong generic list. bail out
     //        return null;
     //    }
 
-    //    var stack = 0;
-    //    var argumentIndex = 0;
+    //    let stack = 0;
+    //    let argumentIndex = 0;
 
     //    whileLoop:
     //    while (token) {
@@ -24,7 +24,7 @@ module ts.SignatureHelp {
     //            case TypeScript.SyntaxKind.LessThanToken:
     //                if (stack === 0) {
     //                    // Found the beginning of the generic argument expression
-    //                    var lessThanToken = token;
+    //                    let lessThanToken = token;
     //                    token = previousToken(token, /*includeSkippedTokens*/ true);
     //                    if (!token || token.kind() !== TypeScript.SyntaxKind.IdentifierName) {
     //                        break whileLoop;
@@ -64,7 +64,7 @@ module ts.SignatureHelp {
 
     //            case TypeScript.SyntaxKind.CloseBraceToken:
     //                // This can be object type, skip untill we find the matching open brace token
-    //                var unmatchedOpenBraceTokens = 0;
+    //                let unmatchedOpenBraceTokens = 0;
 
     //                // Skip untill the matching open brace token
     //                token = SignatureInfoHelpers.moveBackUpTillMatchingTokenKind(token, TypeScript.SyntaxKind.CloseBraceToken, TypeScript.SyntaxKind.OpenBraceToken);
@@ -135,7 +135,7 @@ module ts.SignatureHelp {
     //    // Skip the current token
     //    token = previousToken(token, /*includeSkippedTokens*/ true);
 
-    //    var stack = 0;
+    //    let stack = 0;
 
     //    while (token) {
     //        if (token.kind() === matchingTokenKind) {
@@ -162,7 +162,7 @@ module ts.SignatureHelp {
     //    // Did not find matching token
     //    return null;
     //}
-    var emptyArray: any[] = [];
+    let emptyArray: any[] = [];
 
     const enum ArgumentListKind {
         TypeArguments,
@@ -180,13 +180,13 @@ module ts.SignatureHelp {
 
     export function getSignatureHelpItems(sourceFile: SourceFile, position: number, typeInfoResolver: TypeChecker, cancellationToken: CancellationTokenObject): SignatureHelpItems {
         // Decide whether to show signature help
-        var startingToken = findTokenOnLeftOfPosition(sourceFile, position);
+        let startingToken = findTokenOnLeftOfPosition(sourceFile, position);
         if (!startingToken) {
             // We are at the beginning of the file
             return undefined;
         }
 
-        var argumentInfo = getContainingArgumentInfo(startingToken);
+        let argumentInfo = getContainingArgumentInfo(startingToken);
         cancellationToken.throwIfCancellationRequested();
 
         // Semantic filtering of signature help
@@ -194,9 +194,9 @@ module ts.SignatureHelp {
             return undefined;
         }
 
-        var call = argumentInfo.invocation;
-        var candidates = <Signature[]>[];
-        var resolvedSignature = typeInfoResolver.getResolvedSignature(call, candidates);
+        let call = argumentInfo.invocation;
+        let candidates = <Signature[]>[];
+        let resolvedSignature = typeInfoResolver.getResolvedSignature(call, candidates);
         cancellationToken.throwIfCancellationRequested();
 
         if (!candidates.length) {
@@ -211,7 +211,7 @@ module ts.SignatureHelp {
          */
         function getImmediatelyContainingArgumentInfo(node: Node): ArgumentListInfo {
             if (node.parent.kind === SyntaxKind.CallExpression || node.parent.kind === SyntaxKind.NewExpression) {
-                var callExpression = <CallExpression>node.parent;
+                let callExpression = <CallExpression>node.parent;
                 // There are 3 cases to handle:
                 //   1. The token introduces a list, and should begin a sig help session
                 //   2. The token is either not associated with a list, or ends a list, so the session should end
@@ -230,15 +230,15 @@ module ts.SignatureHelp {
                     node.kind === SyntaxKind.OpenParenToken) {
                     // Find the list that starts right *after* the < or ( token.
                     // If the user has just opened a list, consider this item 0.
-                    var list = getChildListThatStartsWithOpenerToken(callExpression, node, sourceFile);
-                    var isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
+                    let list = getChildListThatStartsWithOpenerToken(callExpression, node, sourceFile);
+                    let isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
                     Debug.assert(list !== undefined);
                     return {
                         kind: isTypeArgList ? ArgumentListKind.TypeArguments : ArgumentListKind.CallArguments,
                         invocation: callExpression,
                         argumentsSpan: getApplicableSpanForArguments(list),
                         argumentIndex: 0,
-                        argumentCount: getCommaBasedArgCount(list)
+                        argumentCount: getArgumentCount(list)
                     };
                 }
 
@@ -248,25 +248,16 @@ module ts.SignatureHelp {
                 //   - Between the type arguments and the arguments (greater than token)
                 //   - On the target of the call (parent.func)
                 //   - On the 'new' keyword in a 'new' expression
-                var listItemInfo = findListItemInfo(node);
+                let listItemInfo = findListItemInfo(node);
                 if (listItemInfo) {
-                    var list = listItemInfo.list;
-                    var isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
+                    let list = listItemInfo.list;
+                    let isTypeArgList = callExpression.typeArguments && callExpression.typeArguments.pos === list.pos;
 
-                    // The listItemIndex we got back includes commas. Our goal is to return the index of the proper
-                    // item (not including commas). Here are some examples:
-                    //    1. foo(a, b, c #) -> the listItemIndex is 4, we want to return 2
-                    //    2. foo(a, b, # c) -> listItemIndex is 3, we want to return 2
-                    //    3. foo(#a) -> listItemIndex is 0, we want to return 0
-                    //
-                    // In general, we want to subtract the number of commas before the current index.
-                    // But if we are on a comma, we also want to pretend we are on the argument *following*
-                    // the comma. That amounts to taking the ceiling of half the index.
-                    var argumentIndex = (listItemInfo.listItemIndex + 1) >> 1;
+                    let argumentIndex = getArgumentIndex(list, node);
+                    let argumentCount = getArgumentCount(list);
 
-                    var argumentCount = getCommaBasedArgCount(list);
-
-                    Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount, `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`); 
+                    Debug.assert(argumentIndex === 0 || argumentIndex < argumentCount,
+                        `argumentCount < argumentIndex, ${argumentCount} < ${argumentIndex}`); 
 
                     return {
                         kind: isTypeArgList ? ArgumentListKind.TypeArguments : ArgumentListKind.CallArguments,
@@ -285,18 +276,18 @@ module ts.SignatureHelp {
                 }
             }
             else if (node.kind === SyntaxKind.TemplateHead && node.parent.parent.kind === SyntaxKind.TaggedTemplateExpression) {
-                var templateExpression = <TemplateExpression>node.parent;
-                var tagExpression = <TaggedTemplateExpression>templateExpression.parent;
+                let templateExpression = <TemplateExpression>node.parent;
+                let tagExpression = <TaggedTemplateExpression>templateExpression.parent;
                 Debug.assert(templateExpression.kind === SyntaxKind.TemplateExpression);
 
-                var argumentIndex = isInsideTemplateLiteral(<LiteralExpression>node, position) ? 0 : 1;
+                let argumentIndex = isInsideTemplateLiteral(<LiteralExpression>node, position) ? 0 : 1;
 
                 return getArgumentListInfoForTemplate(tagExpression, argumentIndex);
             }
             else if (node.parent.kind === SyntaxKind.TemplateSpan && node.parent.parent.parent.kind === SyntaxKind.TaggedTemplateExpression) {
-                var templateSpan = <TemplateSpan>node.parent;
-                var templateExpression = <TemplateExpression>templateSpan.parent;
-                var tagExpression = <TaggedTemplateExpression>templateExpression.parent;
+                let templateSpan = <TemplateSpan>node.parent;
+                let templateExpression = <TemplateExpression>templateSpan.parent;
+                let tagExpression = <TaggedTemplateExpression>templateExpression.parent;
                 Debug.assert(templateExpression.kind === SyntaxKind.TemplateExpression);
 
                 // If we're just after a template tail, don't show signature help.
@@ -304,8 +295,8 @@ module ts.SignatureHelp {
                     return undefined;
                 }
 
-                var spanIndex = templateExpression.templateSpans.indexOf(templateSpan);
-                var argumentIndex = getArgumentIndexForTemplatePiece(spanIndex, node);
+                let spanIndex = templateExpression.templateSpans.indexOf(templateSpan);
+                let argumentIndex = getArgumentIndexForTemplatePiece(spanIndex, node);
 
                 return getArgumentListInfoForTemplate(tagExpression, argumentIndex);
             }
@@ -313,12 +304,52 @@ module ts.SignatureHelp {
             return undefined;
         }
 
-        function getCommaBasedArgCount(argumentsList: Node) {
-            // The number of arguments is the number of commas plus one, unless the list
-            // is completely empty, in which case there are 0 arguments.
-            return argumentsList.getChildCount() === 0
-                ? 0
-                : 1 + countWhere(argumentsList.getChildren(), arg => arg.kind === SyntaxKind.CommaToken);
+        function getArgumentIndex(argumentsList: Node, node: Node) {
+            // The list we got back can include commas.  In the presence of errors it may 
+            // also just have nodes without commas.  For example "Foo(a b c)" will have 3 
+            // args without commas.   We want to find what index we're at.  So we count
+            // forward until we hit ourselves, only incrementing the index if it isn't a
+            // comma.
+            //
+            // Note: the subtlety around trailing commas (in getArgumentCount) does not apply
+            // here.  That's because we're only walking forward until we hit the node we're
+            // on.  In that case, even if we're after the trailing comma, we'll still see
+            // that trailing comma in the list, and we'll have generated the appropriate
+            // arg index.
+            let argumentIndex = 0;
+            let listChildren = argumentsList.getChildren();
+            for (let child of listChildren) {
+                if (child === node) {
+                    break;
+                }
+                if (child.kind !== SyntaxKind.CommaToken) {
+                    argumentIndex++;
+                }
+            }
+
+            return argumentIndex;
+        }
+
+        function getArgumentCount(argumentsList: Node) {
+            // The argument count for a list is normally the number of non-comma children it has.
+            // For example, if you have "Foo(a,b)" then there will be three children of the arg
+            // list 'a' '<comma>' 'b'.  So, in this case the arg count will be 2.  However, there
+            // is a small subtlety.  If you have  "Foo(a,)", then the child list will just have
+            // 'a' '<comma>'.  So, in the case where the last child is a comma, we increase the
+            // arg count by one to compensate.
+            //
+            // Note: this subtlety only applies to the last comma.  If you had "Foo(a,,"  then 
+            // we'll have:  'a' '<comma>' '<missing>' 
+            // That will give us 2 non-commas.  We then add one for the last comma, givin us an
+            // arg count of 3.
+            let listChildren = argumentsList.getChildren();
+
+            let argumentCount = countWhere(listChildren, arg => arg.kind !== SyntaxKind.CommaToken);
+            if (listChildren.length > 0 && lastOrUndefined(listChildren).kind === SyntaxKind.CommaToken) {
+                argumentCount++;
+            }
+
+            return argumentCount;
         }
 
         // spanIndex is either the index for a given template span.
@@ -347,7 +378,7 @@ module ts.SignatureHelp {
 
         function getArgumentListInfoForTemplate(tagExpression: TaggedTemplateExpression, argumentIndex: number): ArgumentListInfo {
             // argumentCount is either 1 or (numSpans + 1) to account for the template strings array argument.
-            var argumentCount = tagExpression.template.kind === SyntaxKind.NoSubstitutionTemplateLiteral
+            let argumentCount = tagExpression.template.kind === SyntaxKind.NoSubstitutionTemplateLiteral
                 ? 1
                 : (<TemplateExpression>tagExpression.template).templateSpans.length + 1;
 
@@ -371,15 +402,15 @@ module ts.SignatureHelp {
             //
             // The applicable span is from the first bar to the second bar (inclusive,
             // but not including parentheses)
-            var applicableSpanStart = argumentsList.getFullStart();
-            var applicableSpanEnd = skipTrivia(sourceFile.text, argumentsList.getEnd(), /*stopAfterLineBreak*/ false);
+            let applicableSpanStart = argumentsList.getFullStart();
+            let applicableSpanEnd = skipTrivia(sourceFile.text, argumentsList.getEnd(), /*stopAfterLineBreak*/ false);
             return createTextSpan(applicableSpanStart, applicableSpanEnd - applicableSpanStart);
         }
 
         function getApplicableSpanForTaggedTemplate(taggedTemplate: TaggedTemplateExpression): TextSpan {
-            var template = taggedTemplate.template;
-            var applicableSpanStart = template.getStart();
-            var applicableSpanEnd = template.getEnd();
+            let template = taggedTemplate.template;
+            let applicableSpanStart = template.getStart();
+            let applicableSpanEnd = template.getEnd();
 
             // We need to adjust the end position for the case where the template does not have a tail.
             // Otherwise, we will not show signature help past the expression.
@@ -391,7 +422,7 @@ module ts.SignatureHelp {
             // This is because a Missing node has no width. However, what we actually want is to include trivia
             // leading up to the next token in case the user is about to type in a TemplateMiddle or TemplateTail.
             if (template.kind === SyntaxKind.TemplateExpression) {
-                var lastSpan = lastOrUndefined((<TemplateExpression>template).templateSpans);
+                let lastSpan = lastOrUndefined((<TemplateExpression>template).templateSpans);
                 if (lastSpan.literal.getFullWidth() === 0) {
                     applicableSpanEnd = skipTrivia(sourceFile.text, applicableSpanEnd, /*stopAfterLineBreak*/ false);
                 }
@@ -401,7 +432,7 @@ module ts.SignatureHelp {
         }
 
         function getContainingArgumentInfo(node: Node): ArgumentListInfo {
-            for (var n = node; n.kind !== SyntaxKind.SourceFile; n = n.parent) {
+            for (let n = node; n.kind !== SyntaxKind.SourceFile; n = n.parent) {
                 if (isFunctionBlock(n)) {
                     return undefined;
                 }
@@ -412,7 +443,7 @@ module ts.SignatureHelp {
                     Debug.fail("Node of kind " + n.kind + " is not a subspan of its parent of kind " + n.parent.kind);
                 }
 
-                var argumentInfo = getImmediatelyContainingArgumentInfo(n);
+                let argumentInfo = getImmediatelyContainingArgumentInfo(n);
                 if (argumentInfo) {
                     return argumentInfo;
                 }
@@ -424,8 +455,8 @@ module ts.SignatureHelp {
         }
 
         function getChildListThatStartsWithOpenerToken(parent: Node, openerToken: Node, sourceFile: SourceFile): Node {
-            var children = parent.getChildren(sourceFile);
-            var indexOfOpenerToken = children.indexOf(openerToken);
+            let children = parent.getChildren(sourceFile);
+            let indexOfOpenerToken = children.indexOf(openerToken);
             Debug.assert(indexOfOpenerToken >= 0 && children.length > indexOfOpenerToken + 1);
             return children[indexOfOpenerToken + 1];
         }
@@ -439,10 +470,10 @@ module ts.SignatureHelp {
          * or the one with the most parameters.
          */
         function selectBestInvalidOverloadIndex(candidates: Signature[], argumentCount: number): number {
-            var maxParamsSignatureIndex = -1;
-            var maxParams = -1;
-            for (var i = 0; i < candidates.length; i++) {
-                var candidate = candidates[i];
+            let maxParamsSignatureIndex = -1;
+            let maxParams = -1;
+            for (let i = 0; i < candidates.length; i++) {
+                let candidate = candidates[i];
 
                 if (candidate.hasRestParameter || candidate.parameters.length >= argumentCount) {
                     return i;
@@ -458,17 +489,17 @@ module ts.SignatureHelp {
         }
 
         function createSignatureHelpItems(candidates: Signature[], bestSignature: Signature, argumentListInfo: ArgumentListInfo): SignatureHelpItems {
-            var applicableSpan = argumentListInfo.argumentsSpan;
-            var isTypeParameterList = argumentListInfo.kind === ArgumentListKind.TypeArguments;
+            let applicableSpan = argumentListInfo.argumentsSpan;
+            let isTypeParameterList = argumentListInfo.kind === ArgumentListKind.TypeArguments;
 
-            var invocation = argumentListInfo.invocation;
-            var callTarget = getInvokedExpression(invocation)
-            var callTargetSymbol = typeInfoResolver.getSymbolAtLocation(callTarget);
-            var callTargetDisplayParts = callTargetSymbol && symbolToDisplayParts(typeInfoResolver, callTargetSymbol, /*enclosingDeclaration*/ undefined, /*meaning*/ undefined);
-            var items: SignatureHelpItem[] = map(candidates, candidateSignature => {
-                var signatureHelpParameters: SignatureHelpParameter[];
-                var prefixDisplayParts: SymbolDisplayPart[] = [];
-                var suffixDisplayParts: SymbolDisplayPart[] = [];
+            let invocation = argumentListInfo.invocation;
+            let callTarget = getInvokedExpression(invocation)
+            let callTargetSymbol = typeInfoResolver.getSymbolAtLocation(callTarget);
+            let callTargetDisplayParts = callTargetSymbol && symbolToDisplayParts(typeInfoResolver, callTargetSymbol, /*enclosingDeclaration*/ undefined, /*meaning*/ undefined);
+            let items: SignatureHelpItem[] = map(candidates, candidateSignature => {
+                let signatureHelpParameters: SignatureHelpParameter[];
+                let prefixDisplayParts: SymbolDisplayPart[] = [];
+                let suffixDisplayParts: SymbolDisplayPart[] = [];
 
                 if (callTargetDisplayParts) {
                     prefixDisplayParts.push.apply(prefixDisplayParts, callTargetDisplayParts);
@@ -476,25 +507,25 @@ module ts.SignatureHelp {
 
                 if (isTypeParameterList) {
                     prefixDisplayParts.push(punctuationPart(SyntaxKind.LessThanToken));
-                    var typeParameters = candidateSignature.typeParameters;
+                    let typeParameters = candidateSignature.typeParameters;
                     signatureHelpParameters = typeParameters && typeParameters.length > 0 ? map(typeParameters, createSignatureHelpParameterForTypeParameter) : emptyArray;
                     suffixDisplayParts.push(punctuationPart(SyntaxKind.GreaterThanToken));
-                    var parameterParts = mapToDisplayParts(writer =>
+                    let parameterParts = mapToDisplayParts(writer =>
                         typeInfoResolver.getSymbolDisplayBuilder().buildDisplayForParametersAndDelimiters(candidateSignature.parameters, writer, invocation));
                     suffixDisplayParts.push.apply(suffixDisplayParts, parameterParts);
                 }
                 else {
-                    var typeParameterParts = mapToDisplayParts(writer =>
+                    let typeParameterParts = mapToDisplayParts(writer =>
                         typeInfoResolver.getSymbolDisplayBuilder().buildDisplayForTypeParametersAndDelimiters(candidateSignature.typeParameters, writer, invocation));
                     prefixDisplayParts.push.apply(prefixDisplayParts, typeParameterParts);
                     prefixDisplayParts.push(punctuationPart(SyntaxKind.OpenParenToken));
 
-                    var parameters = candidateSignature.parameters;
+                    let parameters = candidateSignature.parameters;
                     signatureHelpParameters = parameters.length > 0 ? map(parameters, createSignatureHelpParameterForParameter) : emptyArray;
                     suffixDisplayParts.push(punctuationPart(SyntaxKind.CloseParenToken));
                 }
 
-                var returnTypeParts = mapToDisplayParts(writer =>
+                let returnTypeParts = mapToDisplayParts(writer =>
                     typeInfoResolver.getSymbolDisplayBuilder().buildReturnTypeDisplay(candidateSignature, writer, invocation));
                 suffixDisplayParts.push.apply(suffixDisplayParts, returnTypeParts);
                 
@@ -508,12 +539,12 @@ module ts.SignatureHelp {
                 };
             });
 
-            var argumentIndex = argumentListInfo.argumentIndex;
+            let argumentIndex = argumentListInfo.argumentIndex;
 
             // argumentCount is the *apparent* number of arguments.
-            var argumentCount = argumentListInfo.argumentCount;
+            let argumentCount = argumentListInfo.argumentCount;
 
-            var selectedItemIndex = candidates.indexOf(bestSignature);
+            let selectedItemIndex = candidates.indexOf(bestSignature);
             if (selectedItemIndex < 0) {
                 selectedItemIndex = selectBestInvalidOverloadIndex(candidates, argumentCount);
             }
@@ -529,10 +560,10 @@ module ts.SignatureHelp {
             };
 
             function createSignatureHelpParameterForParameter(parameter: Symbol): SignatureHelpParameter {
-                var displayParts = mapToDisplayParts(writer =>
+                let displayParts = mapToDisplayParts(writer =>
                     typeInfoResolver.getSymbolDisplayBuilder().buildParameterDisplay(parameter, writer, invocation));
 
-                var isOptional = hasQuestionToken(parameter.valueDeclaration);
+                let isOptional = hasQuestionToken(parameter.valueDeclaration);
 
                 return {
                     name: parameter.name,
@@ -543,7 +574,7 @@ module ts.SignatureHelp {
             }
 
             function createSignatureHelpParameterForTypeParameter(typeParameter: TypeParameter): SignatureHelpParameter {
-                var displayParts = mapToDisplayParts(writer =>
+                let displayParts = mapToDisplayParts(writer =>
                     typeInfoResolver.getSymbolDisplayBuilder().buildTypeParameterDisplay(typeParameter, writer, invocation));
 
                 return {

src/services/utilities.ts

@@ -7,18 +7,18 @@ module ts {
 
     export function getEndLinePosition(line: number, sourceFile: SourceFile): number {
         Debug.assert(line >= 0);
-        var lineStarts = sourceFile.getLineStarts();
+        let lineStarts = sourceFile.getLineStarts();
         
-        var lineIndex = line;
+        let lineIndex = line;
         if (lineIndex + 1 === lineStarts.length) {
             // last line - return EOF
             return sourceFile.text.length - 1;
         }
         else {
             // current line start
-            var start = lineStarts[lineIndex];
+            let start = lineStarts[lineIndex];
             // take the start position of the next line -1 = it should be some line break
-            var pos = lineStarts[lineIndex + 1] - 1;
+            let pos = lineStarts[lineIndex + 1] - 1;
             Debug.assert(isLineBreak(sourceFile.text.charCodeAt(pos)));
             // walk backwards skipping line breaks, stop the the beginning of current line.
             // i.e:
@@ -32,8 +32,8 @@ module ts {
     }
 
     export function getLineStartPositionForPosition(position: number, sourceFile: SourceFile): number {
-        var lineStarts = sourceFile.getLineStarts();
-        var line = sourceFile.getLineAndCharacterOfPosition(position).line;
+        let lineStarts = sourceFile.getLineStarts();
+        let line = sourceFile.getLineAndCharacterOfPosition(position).line;
         return lineStarts[line];
     }
 
@@ -54,13 +54,13 @@ module ts {
     }
 
     export function startEndOverlapsWithStartEnd(start1: number, end1: number, start2: number, end2: number) {
-        var start = Math.max(start1, start2);
-        var end = Math.min(end1, end2);
+        let start = Math.max(start1, start2);
+        let end = Math.min(end1, end2);
         return start < end;
     }
 
     export function findListItemInfo(node: Node): ListItemInfo {
-        var list = findContainingList(node);
+        let list = findContainingList(node);
 
         // It is possible at this point for syntaxList to be undefined, either if
         // node.parent had no list child, or if none of its list children contained
@@ -70,8 +70,8 @@ module ts {
             return undefined;
         }
 
-        var children = list.getChildren();
-        var listItemIndex = indexOf(children, node);
+        let children = list.getChildren();
+        let listItemIndex = indexOf(children, node);
 
         return {
             listItemIndex,
@@ -88,13 +88,15 @@ module ts {
         // be parented by the container of the SyntaxList, not the SyntaxList itself.
         // In order to find the list item index, we first need to locate SyntaxList itself and then search
         // for the position of the relevant node (or comma).
-        var syntaxList = forEach(node.parent.getChildren(), c => {
+        let syntaxList = forEach(node.parent.getChildren(), c => {
             // find syntax list that covers the span of the node
             if (c.kind === SyntaxKind.SyntaxList && c.pos <= node.pos && c.end >= node.end) {
                 return c;
             }
         });
 
+        // Either we didn't find an appropriate list, or the list must contain us.
+        Debug.assert(!syntaxList || contains(syntaxList.getChildren(), node)); 
         return syntaxList;
     }
 
@@ -124,7 +126,7 @@ module ts {
 
     /** Get the token whose text contains the position */
     function getTokenAtPositionWorker(sourceFile: SourceFile, position: number, allowPositionInLeadingTrivia: boolean, includeItemAtEndPosition: (n: Node) => boolean): Node {
-        var current: Node = sourceFile;
+        let current: Node = sourceFile;
         outer: while (true) {
             if (isToken(current)) {
                 // exit early
@@ -132,17 +134,17 @@ module ts {
             }
 
             // find the child that contains 'position'
-            for (var i = 0, n = current.getChildCount(sourceFile); i < n; i++) {
-                var child = current.getChildAt(i);
-                var start = allowPositionInLeadingTrivia ? child.getFullStart() : child.getStart(sourceFile);
+            for (let i = 0, n = current.getChildCount(sourceFile); i < n; i++) {
+                let child = current.getChildAt(i);
+                let start = allowPositionInLeadingTrivia ? child.getFullStart() : child.getStart(sourceFile);
                 if (start <= position) {
-                    var end = child.getEnd();
+                    let end = child.getEnd();
                     if (position < end || (position === end && child.kind === SyntaxKind.EndOfFileToken)) {
                         current = child;
                         continue outer;
                     }
                     else if (includeItemAtEndPosition && end === position) {
-                        var previousToken = findPrecedingToken(position, sourceFile, child);
+                        let previousToken = findPrecedingToken(position, sourceFile, child);
                         if (previousToken && includeItemAtEndPosition(previousToken)) {
                             return previousToken;
                         }
@@ -164,7 +166,7 @@ module ts {
     export function findTokenOnLeftOfPosition(file: SourceFile, position: number): Node {
         // Ideally, getTokenAtPosition should return a token. However, it is currently
         // broken, so we do a check to make sure the result was indeed a token.
-        var tokenAtPosition = getTokenAtPosition(file, position);
+        let tokenAtPosition = getTokenAtPosition(file, position);
         if (isToken(tokenAtPosition) && position > tokenAtPosition.getStart(file) && position < tokenAtPosition.getEnd()) {
             return tokenAtPosition;
         }
@@ -181,10 +183,9 @@ module ts {
                 return n;
             }
 
-            var children = n.getChildren();
-            for (var i = 0, len = children.length; i < len; ++i) {
-                var child = children[i];
-                var shouldDiveInChildNode =
+            let children = n.getChildren();
+            for (let child of children) {
+                let shouldDiveInChildNode =
                     // previous token is enclosed somewhere in the child
                     (child.pos <= previousToken.pos && child.end > previousToken.end) ||
                     // previous token ends exactly at the beginning of child
@@ -207,8 +208,8 @@ module ts {
                 return n;
             }
 
-            var children = n.getChildren();
-            var candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
+            let children = n.getChildren();
+            let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
             return candidate && findRightmostToken(candidate);
 
         }
@@ -218,14 +219,14 @@ module ts {
                 return n;
             }
 
-            var children = n.getChildren();
-            for (var i = 0, len = children.length; i < len; ++i) {
-                var child = children[i];
+            let children = n.getChildren();
+            for (let i = 0, len = children.length; i < len; i++) {
+                let child = children[i];
                 if (nodeHasTokens(child)) {
                     if (position <= child.end) {
                         if (child.getStart(sourceFile) >= position) {
                             // actual start of the node is past the position - previous token should be at the end of previous child
-                            var candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ i);
+                            let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ i);
                             return candidate && findRightmostToken(candidate)
                         }
                         else {
@@ -243,14 +244,14 @@ module ts {
             // Try to find the rightmost token in the file without filtering.
             // Namely we are skipping the check: 'position < node.end'
             if (children.length) {
-                var candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
+                let candidate = findRightmostChildNodeWithTokens(children, /*exclusiveStartPosition*/ children.length);
                 return candidate && findRightmostToken(candidate);
             }
         }
 
         /// finds last node that is considered as candidate for search (isCandidate(node) === true) starting from 'exclusiveStartPosition'
         function findRightmostChildNodeWithTokens(children: Node[], exclusiveStartPosition: number): Node {
-            for (var i = exclusiveStartPosition - 1; i >= 0; --i) {
+            for (let i = exclusiveStartPosition - 1; i >= 0; --i) {
                 if (nodeHasTokens(children[i])) {
                     return children[i];
                 }
@@ -265,8 +266,8 @@ module ts {
     }
 
     export function getNodeModifiers(node: Node): string {
-        var flags = getCombinedNodeFlags(node);
-        var result: string[] = [];
+        let flags = getCombinedNodeFlags(node);
+        let result: string[] = [];
 
         if (flags & NodeFlags.Private) result.push(ScriptElementKindModifier.privateMemberModifier);
         if (flags & NodeFlags.Protected) result.push(ScriptElementKindModifier.protectedMemberModifier);
@@ -316,7 +317,7 @@ module ts {
     }
 
     export function compareDataObjects(dst: any, src: any): boolean {
-        for (var e in dst) {
+        for (let e in dst) {
             if (typeof dst[e] === "object") {
                 if (!compareDataObjects(dst[e], src[e])) {
                     return false;
@@ -338,11 +339,11 @@ module ts {
         return symbol.declarations && symbol.declarations.length > 0 && symbol.declarations[0].kind === SyntaxKind.Parameter;
     }
 
-    var displayPartWriter = getDisplayPartWriter();
+    let displayPartWriter = getDisplayPartWriter();
     function getDisplayPartWriter(): DisplayPartsSymbolWriter {
-        var displayParts: SymbolDisplayPart[];
-        var lineStart: boolean;
-        var indent: number;
+        let displayParts: SymbolDisplayPart[];
+        let lineStart: boolean;
+        let indent: number;
 
         resetWriter();
         return {
@@ -363,7 +364,7 @@ module ts {
 
         function writeIndent() {
             if (lineStart) {
-                var indentString = getIndentString(indent);
+                let indentString = getIndentString(indent);
                 if (indentString) {
                     displayParts.push(displayPart(indentString, SymbolDisplayPartKind.space));
                 }
@@ -397,7 +398,7 @@ module ts {
         return displayPart(text, displayPartKind(symbol), symbol);
 
         function displayPartKind(symbol: Symbol): SymbolDisplayPartKind {
-            var flags = symbol.flags;
+            let flags = symbol.flags;
 
             if (flags & SymbolFlags.Variable) {
                 return isFirstDeclarationOfSymbolParameter(symbol) ? SymbolDisplayPartKind.parameterName : SymbolDisplayPartKind.localName;
@@ -454,7 +455,7 @@ module ts {
 
     export function mapToDisplayParts(writeDisplayParts: (writer: DisplayPartsSymbolWriter) => void): SymbolDisplayPart[] {
         writeDisplayParts(displayPartWriter);
-        var result = displayPartWriter.displayParts();
+        let result = displayPartWriter.displayParts();
         displayPartWriter.clear();
         return result;
     }

tests/baselines/reference/APISample_compile.js

@@ -261,27 +261,28 @@ declare module "typescript" {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -656,6 +657,9 @@ declare module "typescript" {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1484,7 +1488,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;
         getChildCount(sourceFile?: SourceFile): number;
@@ -1971,7 +1975,7 @@ declare module "typescript" {
         throwIfCancellationRequested(): void;
     }
     function createLanguageServiceSourceFile(fileName: string, scriptSnapshot: IScriptSnapshot, scriptTarget: ScriptTarget, version: string, setNodeParents: boolean): SourceFile;
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
     function createDocumentRegistry(): DocumentRegistry;
     function preProcessFile(sourceText: string, readImportFiles?: boolean): PreProcessedFileInfo;

tests/baselines/reference/APISample_compile.types

@@ -801,67 +801,70 @@ declare module "typescript" {
         ModuleBlock = 201,
 >ModuleBlock : SyntaxKind
 
-        ImportEqualsDeclaration = 202,
+        CaseBlock = 202,
+>CaseBlock : SyntaxKind
+
+        ImportEqualsDeclaration = 203,
 >ImportEqualsDeclaration : SyntaxKind
 
-        ImportDeclaration = 203,
+        ImportDeclaration = 204,
 >ImportDeclaration : SyntaxKind
 
-        ImportClause = 204,
+        ImportClause = 205,
 >ImportClause : SyntaxKind
 
-        NamespaceImport = 205,
+        NamespaceImport = 206,
 >NamespaceImport : SyntaxKind
 
-        NamedImports = 206,
+        NamedImports = 207,
 >NamedImports : SyntaxKind
 
-        ImportSpecifier = 207,
+        ImportSpecifier = 208,
 >ImportSpecifier : SyntaxKind
 
-        ExportAssignment = 208,
+        ExportAssignment = 209,
 >ExportAssignment : SyntaxKind
 
-        ExportDeclaration = 209,
+        ExportDeclaration = 210,
 >ExportDeclaration : SyntaxKind
 
-        NamedExports = 210,
+        NamedExports = 211,
 >NamedExports : SyntaxKind
 
-        ExportSpecifier = 211,
+        ExportSpecifier = 212,
 >ExportSpecifier : SyntaxKind
 
-        ExternalModuleReference = 212,
+        ExternalModuleReference = 213,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 213,
+        CaseClause = 214,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 214,
+        DefaultClause = 215,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 215,
+        HeritageClause = 216,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 216,
+        CatchClause = 217,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 217,
+        PropertyAssignment = 218,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 219,
+        EnumMember = 220,
 >EnumMember : SyntaxKind
 
-        SourceFile = 220,
+        SourceFile = 221,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 221,
+        SyntaxList = 222,
 >SyntaxList : SyntaxKind
 
-        Count = 222,
+        Count = 223,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -1980,6 +1983,14 @@ declare module "typescript" {
 >expression : Expression
 >Expression : Expression
 
+        caseBlock: CaseBlock;
+>caseBlock : CaseBlock
+>CaseBlock : CaseBlock
+    }
+    interface CaseBlock extends Node {
+>CaseBlock : CaseBlock
+>Node : Node
+
         clauses: NodeArray<CaseOrDefaultClause>;
 >clauses : NodeArray<CaseClause | DefaultClause>
 >NodeArray : NodeArray<T>
@@ -4757,7 +4768,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
 >servicesVersion : string
 
     interface Node {
@@ -6107,7 +6118,7 @@ declare module "typescript" {
 >setNodeParents : boolean
 >SourceFile : SourceFile
 
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
 >disableIncrementalParsing : boolean
 
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;

tests/baselines/reference/APISample_linter.js

@@ -292,27 +292,28 @@ declare module "typescript" {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -687,6 +688,9 @@ declare module "typescript" {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1515,7 +1519,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;
         getChildCount(sourceFile?: SourceFile): number;
@@ -2002,7 +2006,7 @@ declare module "typescript" {
         throwIfCancellationRequested(): void;
     }
     function createLanguageServiceSourceFile(fileName: string, scriptSnapshot: IScriptSnapshot, scriptTarget: ScriptTarget, version: string, setNodeParents: boolean): SourceFile;
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
     function createDocumentRegistry(): DocumentRegistry;
     function preProcessFile(sourceText: string, readImportFiles?: boolean): PreProcessedFileInfo;

tests/baselines/reference/APISample_linter.types

@@ -947,67 +947,70 @@ declare module "typescript" {
         ModuleBlock = 201,
 >ModuleBlock : SyntaxKind
 
-        ImportEqualsDeclaration = 202,
+        CaseBlock = 202,
+>CaseBlock : SyntaxKind
+
+        ImportEqualsDeclaration = 203,
 >ImportEqualsDeclaration : SyntaxKind
 
-        ImportDeclaration = 203,
+        ImportDeclaration = 204,
 >ImportDeclaration : SyntaxKind
 
-        ImportClause = 204,
+        ImportClause = 205,
 >ImportClause : SyntaxKind
 
-        NamespaceImport = 205,
+        NamespaceImport = 206,
 >NamespaceImport : SyntaxKind
 
-        NamedImports = 206,
+        NamedImports = 207,
 >NamedImports : SyntaxKind
 
-        ImportSpecifier = 207,
+        ImportSpecifier = 208,
 >ImportSpecifier : SyntaxKind
 
-        ExportAssignment = 208,
+        ExportAssignment = 209,
 >ExportAssignment : SyntaxKind
 
-        ExportDeclaration = 209,
+        ExportDeclaration = 210,
 >ExportDeclaration : SyntaxKind
 
-        NamedExports = 210,
+        NamedExports = 211,
 >NamedExports : SyntaxKind
 
-        ExportSpecifier = 211,
+        ExportSpecifier = 212,
 >ExportSpecifier : SyntaxKind
 
-        ExternalModuleReference = 212,
+        ExternalModuleReference = 213,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 213,
+        CaseClause = 214,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 214,
+        DefaultClause = 215,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 215,
+        HeritageClause = 216,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 216,
+        CatchClause = 217,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 217,
+        PropertyAssignment = 218,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 219,
+        EnumMember = 220,
 >EnumMember : SyntaxKind
 
-        SourceFile = 220,
+        SourceFile = 221,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 221,
+        SyntaxList = 222,
 >SyntaxList : SyntaxKind
 
-        Count = 222,
+        Count = 223,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -2126,6 +2129,14 @@ declare module "typescript" {
 >expression : Expression
 >Expression : Expression
 
+        caseBlock: CaseBlock;
+>caseBlock : CaseBlock
+>CaseBlock : CaseBlock
+    }
+    interface CaseBlock extends Node {
+>CaseBlock : CaseBlock
+>Node : Node
+
         clauses: NodeArray<CaseOrDefaultClause>;
 >clauses : NodeArray<CaseClause | DefaultClause>
 >NodeArray : NodeArray<T>
@@ -4903,7 +4914,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
 >servicesVersion : string
 
     interface Node {
@@ -6253,7 +6264,7 @@ declare module "typescript" {
 >setNodeParents : boolean
 >SourceFile : SourceFile
 
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
 >disableIncrementalParsing : boolean
 
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;

tests/baselines/reference/APISample_transform.js

@@ -293,27 +293,28 @@ declare module "typescript" {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -688,6 +689,9 @@ declare module "typescript" {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1516,7 +1520,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;
         getChildCount(sourceFile?: SourceFile): number;
@@ -2003,7 +2007,7 @@ declare module "typescript" {
         throwIfCancellationRequested(): void;
     }
     function createLanguageServiceSourceFile(fileName: string, scriptSnapshot: IScriptSnapshot, scriptTarget: ScriptTarget, version: string, setNodeParents: boolean): SourceFile;
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
     function createDocumentRegistry(): DocumentRegistry;
     function preProcessFile(sourceText: string, readImportFiles?: boolean): PreProcessedFileInfo;

tests/baselines/reference/APISample_transform.types

@@ -897,67 +897,70 @@ declare module "typescript" {
         ModuleBlock = 201,
 >ModuleBlock : SyntaxKind
 
-        ImportEqualsDeclaration = 202,
+        CaseBlock = 202,
+>CaseBlock : SyntaxKind
+
+        ImportEqualsDeclaration = 203,
 >ImportEqualsDeclaration : SyntaxKind
 
-        ImportDeclaration = 203,
+        ImportDeclaration = 204,
 >ImportDeclaration : SyntaxKind
 
-        ImportClause = 204,
+        ImportClause = 205,
 >ImportClause : SyntaxKind
 
-        NamespaceImport = 205,
+        NamespaceImport = 206,
 >NamespaceImport : SyntaxKind
 
-        NamedImports = 206,
+        NamedImports = 207,
 >NamedImports : SyntaxKind
 
-        ImportSpecifier = 207,
+        ImportSpecifier = 208,
 >ImportSpecifier : SyntaxKind
 
-        ExportAssignment = 208,
+        ExportAssignment = 209,
 >ExportAssignment : SyntaxKind
 
-        ExportDeclaration = 209,
+        ExportDeclaration = 210,
 >ExportDeclaration : SyntaxKind
 
-        NamedExports = 210,
+        NamedExports = 211,
 >NamedExports : SyntaxKind
 
-        ExportSpecifier = 211,
+        ExportSpecifier = 212,
 >ExportSpecifier : SyntaxKind
 
-        ExternalModuleReference = 212,
+        ExternalModuleReference = 213,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 213,
+        CaseClause = 214,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 214,
+        DefaultClause = 215,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 215,
+        HeritageClause = 216,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 216,
+        CatchClause = 217,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 217,
+        PropertyAssignment = 218,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 219,
+        EnumMember = 220,
 >EnumMember : SyntaxKind
 
-        SourceFile = 220,
+        SourceFile = 221,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 221,
+        SyntaxList = 222,
 >SyntaxList : SyntaxKind
 
-        Count = 222,
+        Count = 223,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -2076,6 +2079,14 @@ declare module "typescript" {
 >expression : Expression
 >Expression : Expression
 
+        caseBlock: CaseBlock;
+>caseBlock : CaseBlock
+>CaseBlock : CaseBlock
+    }
+    interface CaseBlock extends Node {
+>CaseBlock : CaseBlock
+>Node : Node
+
         clauses: NodeArray<CaseOrDefaultClause>;
 >clauses : NodeArray<CaseClause | DefaultClause>
 >NodeArray : NodeArray<T>
@@ -4853,7 +4864,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
 >servicesVersion : string
 
     interface Node {
@@ -6203,7 +6214,7 @@ declare module "typescript" {
 >setNodeParents : boolean
 >SourceFile : SourceFile
 
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
 >disableIncrementalParsing : boolean
 
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;

tests/baselines/reference/APISample_watcher.js

@@ -330,27 +330,28 @@ declare module "typescript" {
         EnumDeclaration = 199,
         ModuleDeclaration = 200,
         ModuleBlock = 201,
-        ImportEqualsDeclaration = 202,
-        ImportDeclaration = 203,
-        ImportClause = 204,
-        NamespaceImport = 205,
-        NamedImports = 206,
-        ImportSpecifier = 207,
-        ExportAssignment = 208,
-        ExportDeclaration = 209,
-        NamedExports = 210,
-        ExportSpecifier = 211,
-        ExternalModuleReference = 212,
-        CaseClause = 213,
-        DefaultClause = 214,
-        HeritageClause = 215,
-        CatchClause = 216,
-        PropertyAssignment = 217,
-        ShorthandPropertyAssignment = 218,
-        EnumMember = 219,
-        SourceFile = 220,
-        SyntaxList = 221,
-        Count = 222,
+        CaseBlock = 202,
+        ImportEqualsDeclaration = 203,
+        ImportDeclaration = 204,
+        ImportClause = 205,
+        NamespaceImport = 206,
+        NamedImports = 207,
+        ImportSpecifier = 208,
+        ExportAssignment = 209,
+        ExportDeclaration = 210,
+        NamedExports = 211,
+        ExportSpecifier = 212,
+        ExternalModuleReference = 213,
+        CaseClause = 214,
+        DefaultClause = 215,
+        HeritageClause = 216,
+        CatchClause = 217,
+        PropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
+        EnumMember = 220,
+        SourceFile = 221,
+        SyntaxList = 222,
+        Count = 223,
         FirstAssignment = 52,
         LastAssignment = 63,
         FirstReservedWord = 65,
@@ -725,6 +726,9 @@ declare module "typescript" {
     }
     interface SwitchStatement extends Statement {
         expression: Expression;
+        caseBlock: CaseBlock;
+    }
+    interface CaseBlock extends Node {
         clauses: NodeArray<CaseOrDefaultClause>;
     }
     interface CaseClause extends Node {
@@ -1553,7 +1557,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
     interface Node {
         getSourceFile(): SourceFile;
         getChildCount(sourceFile?: SourceFile): number;
@@ -2040,7 +2044,7 @@ declare module "typescript" {
         throwIfCancellationRequested(): void;
     }
     function createLanguageServiceSourceFile(fileName: string, scriptSnapshot: IScriptSnapshot, scriptTarget: ScriptTarget, version: string, setNodeParents: boolean): SourceFile;
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;
     function createDocumentRegistry(): DocumentRegistry;
     function preProcessFile(sourceText: string, readImportFiles?: boolean): PreProcessedFileInfo;

tests/baselines/reference/APISample_watcher.types

@@ -1070,67 +1070,70 @@ declare module "typescript" {
         ModuleBlock = 201,
 >ModuleBlock : SyntaxKind
 
-        ImportEqualsDeclaration = 202,
+        CaseBlock = 202,
+>CaseBlock : SyntaxKind
+
+        ImportEqualsDeclaration = 203,
 >ImportEqualsDeclaration : SyntaxKind
 
-        ImportDeclaration = 203,
+        ImportDeclaration = 204,
 >ImportDeclaration : SyntaxKind
 
-        ImportClause = 204,
+        ImportClause = 205,
 >ImportClause : SyntaxKind
 
-        NamespaceImport = 205,
+        NamespaceImport = 206,
 >NamespaceImport : SyntaxKind
 
-        NamedImports = 206,
+        NamedImports = 207,
 >NamedImports : SyntaxKind
 
-        ImportSpecifier = 207,
+        ImportSpecifier = 208,
 >ImportSpecifier : SyntaxKind
 
-        ExportAssignment = 208,
+        ExportAssignment = 209,
 >ExportAssignment : SyntaxKind
 
-        ExportDeclaration = 209,
+        ExportDeclaration = 210,
 >ExportDeclaration : SyntaxKind
 
-        NamedExports = 210,
+        NamedExports = 211,
 >NamedExports : SyntaxKind
 
-        ExportSpecifier = 211,
+        ExportSpecifier = 212,
 >ExportSpecifier : SyntaxKind
 
-        ExternalModuleReference = 212,
+        ExternalModuleReference = 213,
 >ExternalModuleReference : SyntaxKind
 
-        CaseClause = 213,
+        CaseClause = 214,
 >CaseClause : SyntaxKind
 
-        DefaultClause = 214,
+        DefaultClause = 215,
 >DefaultClause : SyntaxKind
 
-        HeritageClause = 215,
+        HeritageClause = 216,
 >HeritageClause : SyntaxKind
 
-        CatchClause = 216,
+        CatchClause = 217,
 >CatchClause : SyntaxKind
 
-        PropertyAssignment = 217,
+        PropertyAssignment = 218,
 >PropertyAssignment : SyntaxKind
 
-        ShorthandPropertyAssignment = 218,
+        ShorthandPropertyAssignment = 219,
 >ShorthandPropertyAssignment : SyntaxKind
 
-        EnumMember = 219,
+        EnumMember = 220,
 >EnumMember : SyntaxKind
 
-        SourceFile = 220,
+        SourceFile = 221,
 >SourceFile : SyntaxKind
 
-        SyntaxList = 221,
+        SyntaxList = 222,
 >SyntaxList : SyntaxKind
 
-        Count = 222,
+        Count = 223,
 >Count : SyntaxKind
 
         FirstAssignment = 52,
@@ -2249,6 +2252,14 @@ declare module "typescript" {
 >expression : Expression
 >Expression : Expression
 
+        caseBlock: CaseBlock;
+>caseBlock : CaseBlock
+>CaseBlock : CaseBlock
+    }
+    interface CaseBlock extends Node {
+>CaseBlock : CaseBlock
+>Node : Node
+
         clauses: NodeArray<CaseOrDefaultClause>;
 >clauses : NodeArray<CaseClause | DefaultClause>
 >NodeArray : NodeArray<T>
@@ -5026,7 +5037,7 @@ declare module "typescript" {
 }
 declare module "typescript" {
     /** The version of the language service API */
-    var servicesVersion: string;
+    let servicesVersion: string;
 >servicesVersion : string
 
     interface Node {
@@ -6376,7 +6387,7 @@ declare module "typescript" {
 >setNodeParents : boolean
 >SourceFile : SourceFile
 
-    var disableIncrementalParsing: boolean;
+    let disableIncrementalParsing: boolean;
 >disableIncrementalParsing : boolean
 
     function updateLanguageServiceSourceFile(sourceFile: SourceFile, scriptSnapshot: IScriptSnapshot, version: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile;

tests/baselines/reference/ES3For-ofTypeCheck1.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck1.ts(1,15): error TS2494: Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck1.ts (1 errors) ====
+    for (var v of "") { }
+                  ~~
+!!! error TS2494: Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher.

tests/baselines/reference/ES3For-ofTypeCheck1.js

@@ -0,0 +1,7 @@
+//// [ES3For-ofTypeCheck1.ts]
+for (var v of "") { }
+
+//// [ES3For-ofTypeCheck1.js]
+for (var _i = 0, _a = ""; _i < _a.length; _i++) {
+    var v = _a[_i];
+}

tests/baselines/reference/ES3For-ofTypeCheck2.js

@@ -0,0 +1,9 @@
+//// [ES3For-ofTypeCheck2.ts]
+for (var v of [true]) { }
+
+//// [ES3For-ofTypeCheck2.js]
+for (var _i = 0, _a = [
+    true
+]; _i < _a.length; _i++) {
+    var v = _a[_i];
+}

tests/baselines/reference/ES3For-ofTypeCheck2.types

@@ -0,0 +1,5 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck2.ts ===
+for (var v of [true]) { }
+>v : boolean
+>[true] : boolean[]
+

tests/baselines/reference/ES3For-ofTypeCheck4.errors.txt

@@ -0,0 +1,8 @@
+tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck4.ts(2,17): error TS2494: Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck4.ts (1 errors) ====
+    var union: string | string[];
+    for (const v of union) { }
+                    ~~~~~
+!!! error TS2494: Using a string in a 'for...of' statement is only supported in ECMAScript 5 and higher.

tests/baselines/reference/ES3For-ofTypeCheck4.js

@@ -0,0 +1,9 @@
+//// [ES3For-ofTypeCheck4.ts]
+var union: string | string[];
+for (const v of union) { }
+
+//// [ES3For-ofTypeCheck4.js]
+var union;
+for (var _i = 0; _i < union.length; _i++) {
+    var v = union[_i];
+}

tests/baselines/reference/ES3For-ofTypeCheck6.js

@@ -0,0 +1,9 @@
+//// [ES3For-ofTypeCheck6.ts]
+var union: string[] | number[];
+for (var v of union) { }
+
+//// [ES3For-ofTypeCheck6.js]
+var union;
+for (var _i = 0; _i < union.length; _i++) {
+    var v = union[_i];
+}

tests/baselines/reference/ES3For-ofTypeCheck6.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES3For-ofTypeCheck6.ts ===
+var union: string[] | number[];
+>union : string[] | number[]
+
+for (var v of union) { }
+>v : string | number
+>union : string[] | number[]
+

tests/baselines/reference/ES5For-of1.errors.txt

@@ -0,0 +1,9 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of1.ts(2,5): error TS2304: Cannot find name 'console'.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of1.ts (1 errors) ====
+    for (var v of ['a', 'b', 'c']) {
+        console.log(v);
+        ~~~~~~~
+!!! error TS2304: Cannot find name 'console'.
+    }

tests/baselines/reference/ES5For-of1.js

@@ -0,0 +1,15 @@
+//// [ES5For-of1.ts]
+for (var v of ['a', 'b', 'c']) {
+    console.log(v);
+}
+
+//// [ES5For-of1.js]
+for (var _i = 0, _a = [
+    'a',
+    'b',
+    'c'
+]; _i < _a.length; _i++) {
+    var v = _a[_i];
+    console.log(v);
+}
+//# sourceMappingURL=ES5For-of1.js.map

tests/baselines/reference/ES5For-of1.js.map

@@ -0,0 +1,2 @@
+//// [ES5For-of1.js.map]
+{"version":3,"file":"ES5For-of1.js","sourceRoot":"","sources":["ES5For-of1.ts"],"names":[],"mappings":"AAAA,GAAG,CAAC,CAAU,UAAe,EAAf;IAAC,GAAG;IAAE,GAAG;IAAE,GAAG;CAAC,EAAxB,cAAK,EAAL,IAAwB,CAAC;IAAzB,IAAI,CAAC,SAAA;IACN,OAAO,CAAC,GAAG,CAAC,CAAC,CAAC,CAAC;CAClB"}

tests/baselines/reference/ES5For-of1.sourcemap.txt

@@ -0,0 +1,127 @@
+===================================================================
+JsFile: ES5For-of1.js
+mapUrl: ES5For-of1.js.map
+sourceRoot: 
+sources: ES5For-of1.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/conformance/statements/for-ofStatements/ES5For-of1.js
+sourceFile:ES5For-of1.ts
+-------------------------------------------------------------------
+>>>for (var _i = 0, _a = [
+1 >
+2 >^^^
+3 >   ^
+4 >    ^
+5 >     ^^^^^^^^^^
+6 >               ^^
+1 >
+2 >for
+3 >    
+4 >    (var v of 
+5 >     ['a', 'b', 'c']
+6 >               
+1 >Emitted(1, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(1, 4) Source(1, 4) + SourceIndex(0)
+3 >Emitted(1, 5) Source(1, 5) + SourceIndex(0)
+4 >Emitted(1, 6) Source(1, 15) + SourceIndex(0)
+5 >Emitted(1, 16) Source(1, 30) + SourceIndex(0)
+6 >Emitted(1, 18) Source(1, 15) + SourceIndex(0)
+---
+>>>    'a',
+1 >^^^^
+2 >    ^^^
+3 >       ^^->
+1 >[
+2 >    'a'
+1 >Emitted(2, 5) Source(1, 16) + SourceIndex(0)
+2 >Emitted(2, 8) Source(1, 19) + SourceIndex(0)
+---
+>>>    'b',
+1->^^^^
+2 >    ^^^
+3 >       ^->
+1->, 
+2 >    'b'
+1->Emitted(3, 5) Source(1, 21) + SourceIndex(0)
+2 >Emitted(3, 8) Source(1, 24) + SourceIndex(0)
+---
+>>>    'c'
+1->^^^^
+2 >    ^^^
+3 >       ^^^^^^^^^^^^^^^^^^^^->
+1->, 
+2 >    'c'
+1->Emitted(4, 5) Source(1, 26) + SourceIndex(0)
+2 >Emitted(4, 8) Source(1, 29) + SourceIndex(0)
+---
+>>>]; _i < _a.length; _i++) {
+1->^
+2 > ^^
+3 >   ^^^^^^^^^^^^^^
+4 >                 ^^
+5 >                   ^^^^
+6 >                       ^
+1->]
+2 > 
+3 >   var v
+4 >                 
+5 >                   var v of ['a', 'b', 'c']
+6 >                       )
+1->Emitted(5, 2) Source(1, 30) + SourceIndex(0)
+2 >Emitted(5, 4) Source(1, 6) + SourceIndex(0)
+3 >Emitted(5, 18) Source(1, 11) + SourceIndex(0)
+4 >Emitted(5, 20) Source(1, 6) + SourceIndex(0)
+5 >Emitted(5, 24) Source(1, 30) + SourceIndex(0)
+6 >Emitted(5, 25) Source(1, 31) + SourceIndex(0)
+---
+>>>    var v = _a[_i];
+1 >^^^^
+2 >    ^^^^
+3 >        ^
+4 >         ^^^^^^^^^
+5 >                  ^^->
+1 >
+2 >    var 
+3 >        v
+4 >         
+1 >Emitted(6, 5) Source(1, 6) + SourceIndex(0)
+2 >Emitted(6, 9) Source(1, 10) + SourceIndex(0)
+3 >Emitted(6, 10) Source(1, 11) + SourceIndex(0)
+4 >Emitted(6, 19) Source(1, 11) + SourceIndex(0)
+---
+>>>    console.log(v);
+1->^^^^
+2 >    ^^^^^^^
+3 >           ^
+4 >            ^^^
+5 >               ^
+6 >                ^
+7 >                 ^
+8 >                  ^
+1-> of ['a', 'b', 'c']) {
+  >    
+2 >    console
+3 >           .
+4 >            log
+5 >               (
+6 >                v
+7 >                 )
+8 >                  ;
+1->Emitted(7, 5) Source(2, 5) + SourceIndex(0)
+2 >Emitted(7, 12) Source(2, 12) + SourceIndex(0)
+3 >Emitted(7, 13) Source(2, 13) + SourceIndex(0)
+4 >Emitted(7, 16) Source(2, 16) + SourceIndex(0)
+5 >Emitted(7, 17) Source(2, 17) + SourceIndex(0)
+6 >Emitted(7, 18) Source(2, 18) + SourceIndex(0)
+7 >Emitted(7, 19) Source(2, 19) + SourceIndex(0)
+8 >Emitted(7, 20) Source(2, 20) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(8, 2) Source(3, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=ES5For-of1.js.map

tests/baselines/reference/ES5For-of10.js

@@ -0,0 +1,22 @@
+//// [ES5For-of10.ts]
+function foo() {
+    return { x: 0 };
+}
+for (foo().x of []) {
+    for (foo().x of [])
+        var p = foo().x;
+}
+
+//// [ES5For-of10.js]
+function foo() {
+    return {
+        x: 0
+    };
+}
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    foo().x = _a[_i];
+    for (var _b = 0, _c = []; _b < _c.length; _b++) {
+        foo().x = _c[_b];
+        var p = foo().x;
+    }
+}

tests/baselines/reference/ES5For-of10.types

@@ -0,0 +1,29 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of10.ts ===
+function foo() {
+>foo : () => { x: number; }
+
+    return { x: 0 };
+>{ x: 0 } : { x: number; }
+>x : number
+}
+for (foo().x of []) {
+>foo().x : number
+>foo() : { x: number; }
+>foo : () => { x: number; }
+>x : number
+>[] : undefined[]
+
+    for (foo().x of [])
+>foo().x : number
+>foo() : { x: number; }
+>foo : () => { x: number; }
+>x : number
+>[] : undefined[]
+
+        var p = foo().x;
+>p : number
+>foo().x : number
+>foo() : { x: number; }
+>foo : () => { x: number; }
+>x : number
+}

tests/baselines/reference/ES5For-of11.js

@@ -0,0 +1,9 @@
+//// [ES5For-of11.ts]
+var v;
+for (v of []) { }
+
+//// [ES5For-of11.js]
+var v;
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    v = _a[_i];
+}

tests/baselines/reference/ES5For-of11.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of11.ts ===
+var v;
+>v : any
+
+for (v of []) { }
+>v : any
+>[] : undefined[]
+

tests/baselines/reference/ES5For-of12.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts(1,7): error TS2364: Invalid left-hand side of assignment expression.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of12.ts (1 errors) ====
+    for ([""] of [[""]]) { }
+          ~~
+!!! error TS2364: Invalid left-hand side of assignment expression.

tests/baselines/reference/ES5For-of12.js

@@ -0,0 +1,11 @@
+//// [ES5For-of12.ts]
+for ([""] of [[""]]) { }
+
+//// [ES5For-of12.js]
+for (var _i = 0, _a = [
+    [
+        ""
+    ]
+]; _i < _a.length; _i++) {
+    "" = _a[_i][0];
+}

tests/baselines/reference/ES5For-of13.js

@@ -0,0 +1,15 @@
+//// [ES5For-of13.ts]
+for (let v of ['a', 'b', 'c']) {
+    var x = v;
+}
+
+//// [ES5For-of13.js]
+for (var _i = 0, _a = [
+    'a',
+    'b',
+    'c'
+]; _i < _a.length; _i++) {
+    var v = _a[_i];
+    var x = v;
+}
+//# sourceMappingURL=ES5For-of13.js.map

tests/baselines/reference/ES5For-of13.js.map

@@ -0,0 +1,2 @@
+//// [ES5For-of13.js.map]
+{"version":3,"file":"ES5For-of13.js","sourceRoot":"","sources":["ES5For-of13.ts"],"names":[],"mappings":"AAAA,GAAG,CAAC,CAAU,UAAe,EAAf;IAAC,GAAG;IAAE,GAAG;IAAE,GAAG;CAAC,EAAxB,cAAK,EAAL,IAAwB,CAAC;IAAzB,IAAI,CAAC,SAAA;IACN,IAAI,CAAC,GAAG,CAAC,CAAC;CACb"}

tests/baselines/reference/ES5For-of13.sourcemap.txt

@@ -0,0 +1,120 @@
+===================================================================
+JsFile: ES5For-of13.js
+mapUrl: ES5For-of13.js.map
+sourceRoot: 
+sources: ES5For-of13.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/conformance/statements/for-ofStatements/ES5For-of13.js
+sourceFile:ES5For-of13.ts
+-------------------------------------------------------------------
+>>>for (var _i = 0, _a = [
+1 >
+2 >^^^
+3 >   ^
+4 >    ^
+5 >     ^^^^^^^^^^
+6 >               ^^
+1 >
+2 >for
+3 >    
+4 >    (let v of 
+5 >     ['a', 'b', 'c']
+6 >               
+1 >Emitted(1, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(1, 4) Source(1, 4) + SourceIndex(0)
+3 >Emitted(1, 5) Source(1, 5) + SourceIndex(0)
+4 >Emitted(1, 6) Source(1, 15) + SourceIndex(0)
+5 >Emitted(1, 16) Source(1, 30) + SourceIndex(0)
+6 >Emitted(1, 18) Source(1, 15) + SourceIndex(0)
+---
+>>>    'a',
+1 >^^^^
+2 >    ^^^
+3 >       ^^->
+1 >[
+2 >    'a'
+1 >Emitted(2, 5) Source(1, 16) + SourceIndex(0)
+2 >Emitted(2, 8) Source(1, 19) + SourceIndex(0)
+---
+>>>    'b',
+1->^^^^
+2 >    ^^^
+3 >       ^->
+1->, 
+2 >    'b'
+1->Emitted(3, 5) Source(1, 21) + SourceIndex(0)
+2 >Emitted(3, 8) Source(1, 24) + SourceIndex(0)
+---
+>>>    'c'
+1->^^^^
+2 >    ^^^
+3 >       ^^^^^^^^^^^^^^^^^^^^->
+1->, 
+2 >    'c'
+1->Emitted(4, 5) Source(1, 26) + SourceIndex(0)
+2 >Emitted(4, 8) Source(1, 29) + SourceIndex(0)
+---
+>>>]; _i < _a.length; _i++) {
+1->^
+2 > ^^
+3 >   ^^^^^^^^^^^^^^
+4 >                 ^^
+5 >                   ^^^^
+6 >                       ^
+1->]
+2 > 
+3 >   let v
+4 >                 
+5 >                   let v of ['a', 'b', 'c']
+6 >                       )
+1->Emitted(5, 2) Source(1, 30) + SourceIndex(0)
+2 >Emitted(5, 4) Source(1, 6) + SourceIndex(0)
+3 >Emitted(5, 18) Source(1, 11) + SourceIndex(0)
+4 >Emitted(5, 20) Source(1, 6) + SourceIndex(0)
+5 >Emitted(5, 24) Source(1, 30) + SourceIndex(0)
+6 >Emitted(5, 25) Source(1, 31) + SourceIndex(0)
+---
+>>>    var v = _a[_i];
+1 >^^^^
+2 >    ^^^^
+3 >        ^
+4 >         ^^^^^^^^^
+1 >
+2 >    let 
+3 >        v
+4 >         
+1 >Emitted(6, 5) Source(1, 6) + SourceIndex(0)
+2 >Emitted(6, 9) Source(1, 10) + SourceIndex(0)
+3 >Emitted(6, 10) Source(1, 11) + SourceIndex(0)
+4 >Emitted(6, 19) Source(1, 11) + SourceIndex(0)
+---
+>>>    var x = v;
+1 >^^^^
+2 >    ^^^^
+3 >        ^
+4 >         ^^^
+5 >            ^
+6 >             ^
+1 > of ['a', 'b', 'c']) {
+  >    
+2 >    var 
+3 >        x
+4 >          = 
+5 >            v
+6 >             ;
+1 >Emitted(7, 5) Source(2, 5) + SourceIndex(0)
+2 >Emitted(7, 9) Source(2, 9) + SourceIndex(0)
+3 >Emitted(7, 10) Source(2, 10) + SourceIndex(0)
+4 >Emitted(7, 13) Source(2, 13) + SourceIndex(0)
+5 >Emitted(7, 14) Source(2, 14) + SourceIndex(0)
+6 >Emitted(7, 15) Source(2, 15) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(8, 2) Source(3, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=ES5For-of13.js.map

tests/baselines/reference/ES5For-of13.types

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of13.ts ===
+for (let v of ['a', 'b', 'c']) {
+>v : string
+>['a', 'b', 'c'] : string[]
+
+    var x = v;
+>x : string
+>v : string
+}

tests/baselines/reference/ES5For-of14.js

@@ -0,0 +1,10 @@
+//// [ES5For-of14.ts]
+for (const v of []) {
+    var x = v;
+}
+
+//// [ES5For-of14.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    var x = v;
+}

tests/baselines/reference/ES5For-of14.types

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of14.ts ===
+for (const v of []) {
+>v : any
+>[] : undefined[]
+
+    var x = v;
+>x : any
+>v : any
+}

tests/baselines/reference/ES5For-of15.js

@@ -0,0 +1,17 @@
+//// [ES5For-of15.ts]
+for (let v of []) {
+    v;
+    for (const v of []) {
+        var x = v;
+    }
+}
+
+//// [ES5For-of15.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    v;
+    for (var _b = 0, _c = []; _b < _c.length; _b++) {
+        var _v = _c[_b];
+        var x = _v;
+    }
+}

tests/baselines/reference/ES5For-of15.types

@@ -0,0 +1,17 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of15.ts ===
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    v;
+>v : any
+
+    for (const v of []) {
+>v : any
+>[] : undefined[]
+
+        var x = v;
+>x : any
+>v : any
+    }
+}

tests/baselines/reference/ES5For-of16.js

@@ -0,0 +1,19 @@
+//// [ES5For-of16.ts]
+for (let v of []) {
+    v;
+    for (let v of []) {
+        var x = v;
+        v++;
+    }
+}
+
+//// [ES5For-of16.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    v;
+    for (var _b = 0, _c = []; _b < _c.length; _b++) {
+        var _v = _c[_b];
+        var x = _v;
+        _v++;
+    }
+}

tests/baselines/reference/ES5For-of16.types

@@ -0,0 +1,21 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of16.ts ===
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    v;
+>v : any
+
+    for (let v of []) {
+>v : any
+>[] : undefined[]
+
+        var x = v;
+>x : any
+>v : any
+
+        v++;
+>v++ : number
+>v : any
+    }
+}

tests/baselines/reference/ES5For-of17.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of17.ts(3,20): error TS2448: Block-scoped variable 'v' used before its declaration.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of17.ts (1 errors) ====
+    for (let v of []) {
+        v;
+        for (let v of [v]) {
+                       ~
+!!! error TS2448: Block-scoped variable 'v' used before its declaration.
+            var x = v;
+            v++;
+        }
+    }

tests/baselines/reference/ES5For-of17.js

@@ -0,0 +1,21 @@
+//// [ES5For-of17.ts]
+for (let v of []) {
+    v;
+    for (let v of [v]) {
+        var x = v;
+        v++;
+    }
+}
+
+//// [ES5For-of17.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    v;
+    for (var _b = 0, _c = [
+        v
+    ]; _b < _c.length; _b++) {
+        var _v = _c[_b];
+        var x = _v;
+        _v++;
+    }
+}

tests/baselines/reference/ES5For-of18.js

@@ -0,0 +1,18 @@
+//// [ES5For-of18.ts]
+for (let v of []) {
+    v;
+}
+for (let v of []) {
+    v;
+}
+
+
+//// [ES5For-of18.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    v;
+}
+for (var _b = 0, _c = []; _b < _c.length; _b++) {
+    var _v = _c[_b];
+    _v;
+}

tests/baselines/reference/ES5For-of18.types

@@ -0,0 +1,16 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of18.ts ===
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    v;
+>v : any
+}
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    v;
+>v : any
+}
+

tests/baselines/reference/ES5For-of19.js

@@ -0,0 +1,22 @@
+//// [ES5For-of19.ts]
+for (let v of []) {
+    v;
+    function foo() {
+        for (const v of []) {
+            v;
+        }
+    }
+}
+
+
+//// [ES5For-of19.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    v;
+    function foo() {
+        for (var _b = 0, _c = []; _b < _c.length; _b++) {
+            var _v = _c[_b];
+            _v;
+        }
+    }
+}

tests/baselines/reference/ES5For-of19.types

@@ -0,0 +1,21 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of19.ts ===
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    v;
+>v : any
+
+    function foo() {
+>foo : () => void
+
+        for (const v of []) {
+>v : any
+>[] : undefined[]
+
+            v;
+>v : any
+        }
+    }
+}
+

tests/baselines/reference/ES5For-of2.js

@@ -0,0 +1,10 @@
+//// [ES5For-of2.ts]
+for (var v of []) {
+    var x = v;
+}
+
+//// [ES5For-of2.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    var x = v;
+}

tests/baselines/reference/ES5For-of2.types

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of2.ts ===
+for (var v of []) {
+>v : any
+>[] : undefined[]
+
+    var x = v;
+>x : any
+>v : any
+}

tests/baselines/reference/ES5For-of20.errors.txt

@@ -0,0 +1,15 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts(3,20): error TS2448: Block-scoped variable 'v' used before its declaration.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts(4,15): error TS1155: 'const' declarations must be initialized
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts (2 errors) ====
+    for (let v of []) {
+        let v;
+        for (let v of [v]) {
+                       ~
+!!! error TS2448: Block-scoped variable 'v' used before its declaration.
+            const v;
+                  ~
+!!! error TS1155: 'const' declarations must be initialized
+        }
+    }

tests/baselines/reference/ES5For-of20.js

@@ -0,0 +1,19 @@
+//// [ES5For-of20.ts]
+for (let v of []) {
+    let v;
+    for (let v of [v]) {
+        const v;
+    }
+}
+
+//// [ES5For-of20.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    var _v;
+    for (var _b = 0, _c = [
+        v
+    ]; _b < _c.length; _b++) {
+        var _v_1 = _c[_b];
+        var _v_2;
+    }
+}

tests/baselines/reference/ES5For-of21.js

@@ -0,0 +1,12 @@
+//// [ES5For-of21.ts]
+for (let v of []) {
+    for (let _i of []) { }
+}
+
+//// [ES5For-of21.js]
+for (var _i = 0, _a = []; _i < _a.length; _i++) {
+    var v = _a[_i];
+    for (var _b = 0, _c = []; _b < _c.length; _b++) {
+        var _i_1 = _c[_b];
+    }
+}

tests/baselines/reference/ES5For-of21.types

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of21.ts ===
+for (let v of []) {
+>v : any
+>[] : undefined[]
+
+    for (let _i of []) { }
+>_i : any
+>[] : undefined[]
+}

tests/baselines/reference/ES5For-of22.errors.txt

@@ -0,0 +1,10 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of22.ts(3,5): error TS2304: Cannot find name 'console'.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of22.ts (1 errors) ====
+    for (var x of [1, 2, 3]) {
+        let _a = 0;
+        console.log(x);
+        ~~~~~~~
+!!! error TS2304: Cannot find name 'console'.
+    }

tests/baselines/reference/ES5For-of22.js

@@ -0,0 +1,16 @@
+//// [ES5For-of22.ts]
+for (var x of [1, 2, 3]) {
+    let _a = 0;
+    console.log(x);
+}
+
+//// [ES5For-of22.js]
+for (var _i = 0, _a = [
+    1,
+    2,
+    3
+]; _i < _a.length; _i++) {
+    var x = _a[_i];
+    var _a_1 = 0;
+    console.log(x);
+}

tests/baselines/reference/ES5For-of23.errors.txt

@@ -0,0 +1,10 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of23.ts(3,5): error TS2304: Cannot find name 'console'.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of23.ts (1 errors) ====
+    for (var x of [1, 2, 3]) {
+        var _a = 0;
+        console.log(x);
+        ~~~~~~~
+!!! error TS2304: Cannot find name 'console'.
+    }

tests/baselines/reference/ES5For-of23.js

@@ -0,0 +1,16 @@
+//// [ES5For-of23.ts]
+for (var x of [1, 2, 3]) {
+    var _a = 0;
+    console.log(x);
+}
+
+//// [ES5For-of23.js]
+for (var _i = 0, _b = [
+    1,
+    2,
+    3
+]; _i < _b.length; _i++) {
+    var x = _b[_i];
+    var _a = 0;
+    console.log(x);
+}

tests/baselines/reference/ES5For-of24.js

@@ -0,0 +1,16 @@
+//// [ES5For-of24.ts]
+var a = [1, 2, 3];
+for (var v of a) {
+    let a = 0;
+}
+
+//// [ES5For-of24.js]
+var a = [
+    1,
+    2,
+    3
+];
+for (var _i = 0; _i < a.length; _i++) {
+    var v = a[_i];
+    var _a = 0;
+}

tests/baselines/reference/ES5For-of24.types

@@ -0,0 +1,12 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of24.ts ===
+var a = [1, 2, 3];
+>a : number[]
+>[1, 2, 3] : number[]
+
+for (var v of a) {
+>v : number
+>a : number[]
+
+    let a = 0;
+>a : number
+}

tests/baselines/reference/ES5For-of25.js

@@ -0,0 +1,19 @@
+//// [ES5For-of25.ts]
+var a = [1, 2, 3];
+for (var v of a) {
+    v;
+    a;
+}
+
+//// [ES5For-of25.js]
+var a = [
+    1,
+    2,
+    3
+];
+for (var _i = 0; _i < a.length; _i++) {
+    var v = a[_i];
+    v;
+    a;
+}
+//# sourceMappingURL=ES5For-of25.js.map

tests/baselines/reference/ES5For-of25.js.map

@@ -0,0 +1,2 @@
+//// [ES5For-of25.js.map]
+{"version":3,"file":"ES5For-of25.js","sourceRoot":"","sources":["ES5For-of25.ts"],"names":[],"mappings":"AAAA,IAAI,CAAC,GAAG;IAAC,CAAC;IAAE,CAAC;IAAE,CAAC;CAAC,CAAC;AAClB,GAAG,CAAC,CAAU,UAAC,EAAV,aAAK,EAAL,IAAU,CAAC;IAAX,IAAI,CAAC,GAAI,CAAC,IAAL;IACN,CAAC,CAAC;IACF,CAAC,CAAC;CACL"}

tests/baselines/reference/ES5For-of25.sourcemap.txt

@@ -0,0 +1,145 @@
+===================================================================
+JsFile: ES5For-of25.js
+mapUrl: ES5For-of25.js.map
+sourceRoot: 
+sources: ES5For-of25.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/conformance/statements/for-ofStatements/ES5For-of25.js
+sourceFile:ES5For-of25.ts
+-------------------------------------------------------------------
+>>>var a = [
+1 >
+2 >^^^^
+3 >    ^
+4 >     ^^^
+1 >
+2 >var 
+3 >    a
+4 >      = 
+1 >Emitted(1, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(1, 5) Source(1, 5) + SourceIndex(0)
+3 >Emitted(1, 6) Source(1, 6) + SourceIndex(0)
+4 >Emitted(1, 9) Source(1, 9) + SourceIndex(0)
+---
+>>>    1,
+1 >^^^^
+2 >    ^
+3 >     ^^->
+1 >[
+2 >    1
+1 >Emitted(2, 5) Source(1, 10) + SourceIndex(0)
+2 >Emitted(2, 6) Source(1, 11) + SourceIndex(0)
+---
+>>>    2,
+1->^^^^
+2 >    ^
+3 >     ^->
+1->, 
+2 >    2
+1->Emitted(3, 5) Source(1, 13) + SourceIndex(0)
+2 >Emitted(3, 6) Source(1, 14) + SourceIndex(0)
+---
+>>>    3
+1->^^^^
+2 >    ^
+1->, 
+2 >    3
+1->Emitted(4, 5) Source(1, 16) + SourceIndex(0)
+2 >Emitted(4, 6) Source(1, 17) + SourceIndex(0)
+---
+>>>];
+1 >^
+2 > ^
+3 >  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >]
+2 > ;
+1 >Emitted(5, 2) Source(1, 18) + SourceIndex(0)
+2 >Emitted(5, 3) Source(1, 19) + SourceIndex(0)
+---
+>>>for (var _i = 0; _i < a.length; _i++) {
+1->
+2 >^^^
+3 >   ^
+4 >    ^
+5 >     ^^^^^^^^^^
+6 >               ^^
+7 >                 ^^^^^^^^^^^^^
+8 >                              ^^
+9 >                                ^^^^
+10>                                    ^
+1->
+  >
+2 >for
+3 >    
+4 >    (var v of 
+5 >     a
+6 >               
+7 >                 var v
+8 >                              
+9 >                                var v of a
+10>                                    )
+1->Emitted(6, 1) Source(2, 1) + SourceIndex(0)
+2 >Emitted(6, 4) Source(2, 4) + SourceIndex(0)
+3 >Emitted(6, 5) Source(2, 5) + SourceIndex(0)
+4 >Emitted(6, 6) Source(2, 15) + SourceIndex(0)
+5 >Emitted(6, 16) Source(2, 16) + SourceIndex(0)
+6 >Emitted(6, 18) Source(2, 6) + SourceIndex(0)
+7 >Emitted(6, 31) Source(2, 11) + SourceIndex(0)
+8 >Emitted(6, 33) Source(2, 6) + SourceIndex(0)
+9 >Emitted(6, 37) Source(2, 16) + SourceIndex(0)
+10>Emitted(6, 38) Source(2, 17) + SourceIndex(0)
+---
+>>>    var v = a[_i];
+1 >^^^^
+2 >    ^^^^
+3 >        ^
+4 >         ^^^
+5 >            ^
+6 >             ^^^^
+1 >
+2 >    var 
+3 >        v
+4 >          of 
+5 >            a
+6 >             
+1 >Emitted(7, 5) Source(2, 6) + SourceIndex(0)
+2 >Emitted(7, 9) Source(2, 10) + SourceIndex(0)
+3 >Emitted(7, 10) Source(2, 11) + SourceIndex(0)
+4 >Emitted(7, 13) Source(2, 15) + SourceIndex(0)
+5 >Emitted(7, 14) Source(2, 16) + SourceIndex(0)
+6 >Emitted(7, 18) Source(2, 11) + SourceIndex(0)
+---
+>>>    v;
+1 >^^^^
+2 >    ^
+3 >     ^
+4 >      ^->
+1 > of a) {
+  >    
+2 >    v
+3 >     ;
+1 >Emitted(8, 5) Source(3, 5) + SourceIndex(0)
+2 >Emitted(8, 6) Source(3, 6) + SourceIndex(0)
+3 >Emitted(8, 7) Source(3, 7) + SourceIndex(0)
+---
+>>>    a;
+1->^^^^
+2 >    ^
+3 >     ^
+1->
+  >    
+2 >    a
+3 >     ;
+1->Emitted(9, 5) Source(4, 5) + SourceIndex(0)
+2 >Emitted(9, 6) Source(4, 6) + SourceIndex(0)
+3 >Emitted(9, 7) Source(4, 7) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(10, 2) Source(5, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=ES5For-of25.js.map

tests/baselines/reference/ES5For-of25.types

@@ -0,0 +1,15 @@
+=== tests/cases/conformance/statements/for-ofStatements/ES5For-of25.ts ===
+var a = [1, 2, 3];
+>a : number[]
+>[1, 2, 3] : number[]
+
+for (var v of a) {
+>v : number
+>a : number[]
+
+    v;
+>v : number
+
+    a;
+>a : number[]
+}

tests/baselines/reference/ES5For-of26.errors.txt

@@ -0,0 +1,10 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of26.ts(1,10): error TS2461: Type 'number' is not an array type.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of26.ts (1 errors) ====
+    for (var [a = 0, b = 1] of [2, 3]) {
+             ~~~~~~~~~~~~~~
+!!! error TS2461: Type 'number' is not an array type.
+        a;
+        b;
+    }

tests/baselines/reference/ES5For-of26.js

@@ -0,0 +1,16 @@
+//// [ES5For-of26.ts]
+for (var [a = 0, b = 1] of [2, 3]) {
+    a;
+    b;
+}
+
+//// [ES5For-of26.js]
+for (var _i = 0, _a = [
+    2,
+    3
+]; _i < _a.length; _i++) {
+    var _b = _a[_i], _c = _b[0], a = _c === void 0 ? 0 : _c, _d = _b[1], b = _d === void 0 ? 1 : _d;
+    a;
+    b;
+}
+//# sourceMappingURL=ES5For-of26.js.map

tests/baselines/reference/ES5For-of26.js.map

@@ -0,0 +1,2 @@
+//// [ES5For-of26.js.map]
+{"version":3,"file":"ES5For-of26.js","sourceRoot":"","sources":["ES5For-of26.ts"],"names":[],"mappings":"AAAA,GAAG,CAAC,CAAuB,UAAM,EAAN;IAAC,CAAC;IAAE,CAAC;CAAC,EAA5B,cAAkB,EAAlB,IAA4B,CAAC;IAA7B,6BAAK,CAAC,mBAAG,CAAC,mBAAE,CAAC,mBAAG,CAAC,KAAC;IACnB,CAAC,CAAC;IACF,CAAC,CAAC;CACL"}

tests/baselines/reference/ES5For-of26.sourcemap.txt

@@ -0,0 +1,134 @@
+===================================================================
+JsFile: ES5For-of26.js
+mapUrl: ES5For-of26.js.map
+sourceRoot: 
+sources: ES5For-of26.ts
+===================================================================
+-------------------------------------------------------------------
+emittedFile:tests/cases/conformance/statements/for-ofStatements/ES5For-of26.js
+sourceFile:ES5For-of26.ts
+-------------------------------------------------------------------
+>>>for (var _i = 0, _a = [
+1 >
+2 >^^^
+3 >   ^
+4 >    ^
+5 >     ^^^^^^^^^^
+6 >               ^^
+1 >
+2 >for
+3 >    
+4 >    (var [a = 0, b = 1] of 
+5 >     [2, 3]
+6 >               
+1 >Emitted(1, 1) Source(1, 1) + SourceIndex(0)
+2 >Emitted(1, 4) Source(1, 4) + SourceIndex(0)
+3 >Emitted(1, 5) Source(1, 5) + SourceIndex(0)
+4 >Emitted(1, 6) Source(1, 28) + SourceIndex(0)
+5 >Emitted(1, 16) Source(1, 34) + SourceIndex(0)
+6 >Emitted(1, 18) Source(1, 28) + SourceIndex(0)
+---
+>>>    2,
+1 >^^^^
+2 >    ^
+3 >     ^->
+1 >[
+2 >    2
+1 >Emitted(2, 5) Source(1, 29) + SourceIndex(0)
+2 >Emitted(2, 6) Source(1, 30) + SourceIndex(0)
+---
+>>>    3
+1->^^^^
+2 >    ^
+3 >     ^^^^^^^^^^^^^^^^^^^^^^->
+1->, 
+2 >    3
+1->Emitted(3, 5) Source(1, 32) + SourceIndex(0)
+2 >Emitted(3, 6) Source(1, 33) + SourceIndex(0)
+---
+>>>]; _i < _a.length; _i++) {
+1->^
+2 > ^^
+3 >   ^^^^^^^^^^^^^^
+4 >                 ^^
+5 >                   ^^^^
+6 >                       ^
+7 >                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1->]
+2 > 
+3 >   var [a = 0, b = 1]
+4 >                 
+5 >                   var [a = 0, b = 1] of [2, 3]
+6 >                       )
+1->Emitted(4, 2) Source(1, 34) + SourceIndex(0)
+2 >Emitted(4, 4) Source(1, 6) + SourceIndex(0)
+3 >Emitted(4, 18) Source(1, 24) + SourceIndex(0)
+4 >Emitted(4, 20) Source(1, 6) + SourceIndex(0)
+5 >Emitted(4, 24) Source(1, 34) + SourceIndex(0)
+6 >Emitted(4, 25) Source(1, 35) + SourceIndex(0)
+---
+>>>    var _b = _a[_i], _c = _b[0], a = _c === void 0 ? 0 : _c, _d = _b[1], b = _d === void 0 ? 1 : _d;
+1->^^^^
+2 >    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 >                                 ^
+4 >                                  ^^^^^^^^^^^^^^^^^^^
+5 >                                                     ^
+6 >                                                      ^^^^^^^^^^^^^^^^^^^
+7 >                                                                         ^
+8 >                                                                          ^^^^^^^^^^^^^^^^^^^
+9 >                                                                                             ^
+10>                                                                                              ^^^^^
+1->
+2 >    var [
+3 >                                 a
+4 >                                   = 
+5 >                                                     0
+6 >                                                      , 
+7 >                                                                         b
+8 >                                                                           = 
+9 >                                                                                             1
+10>                                                                                              ]
+1->Emitted(5, 5) Source(1, 6) + SourceIndex(0)
+2 >Emitted(5, 34) Source(1, 11) + SourceIndex(0)
+3 >Emitted(5, 35) Source(1, 12) + SourceIndex(0)
+4 >Emitted(5, 54) Source(1, 15) + SourceIndex(0)
+5 >Emitted(5, 55) Source(1, 16) + SourceIndex(0)
+6 >Emitted(5, 74) Source(1, 18) + SourceIndex(0)
+7 >Emitted(5, 75) Source(1, 19) + SourceIndex(0)
+8 >Emitted(5, 94) Source(1, 22) + SourceIndex(0)
+9 >Emitted(5, 95) Source(1, 23) + SourceIndex(0)
+10>Emitted(5, 100) Source(1, 24) + SourceIndex(0)
+---
+>>>    a;
+1 >^^^^
+2 >    ^
+3 >     ^
+4 >      ^->
+1 > of [2, 3]) {
+  >    
+2 >    a
+3 >     ;
+1 >Emitted(6, 5) Source(2, 5) + SourceIndex(0)
+2 >Emitted(6, 6) Source(2, 6) + SourceIndex(0)
+3 >Emitted(6, 7) Source(2, 7) + SourceIndex(0)
+---
+>>>    b;
+1->^^^^
+2 >    ^
+3 >     ^
+1->
+  >    
+2 >    b
+3 >     ;
+1->Emitted(7, 5) Source(3, 5) + SourceIndex(0)
+2 >Emitted(7, 6) Source(3, 6) + SourceIndex(0)
+3 >Emitted(7, 7) Source(3, 7) + SourceIndex(0)
+---
+>>>}
+1 >^
+2 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^->
+1 >
+  >}
+1 >Emitted(8, 2) Source(4, 2) + SourceIndex(0)
+---
+>>>//# sourceMappingURL=ES5For-of26.js.map

tests/baselines/reference/ES5For-of27.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,11): error TS2459: Type 'number' has no property 'x' and no string index signature.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts(1,21): error TS2459: Type 'number' has no property 'y' and no string index signature.
+
+
+==== tests/cases/conformance/statements/for-ofStatements/ES5For-of27.ts (2 errors) ====
+    for (var {x: a = 0, y: b = 1} of [2, 3]) {
+              ~
+!!! error TS2459: Type 'number' has no property 'x' and no string index signature.
+                        ~
+!!! error TS2459: Type 'number' has no property 'y' and no string index signature.
+        a;
+        b;
+    }