Merge branch 'master' into typeParametersAsConstraints

Conflicts:
	tests/baselines/reference/functionConstraintSatisfaction2.errors.txt

src/compiler/checker.ts

@@ -51,6 +51,7 @@ namespace ts {
         const emitResolver = createResolver();
 
         const undefinedSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "undefined");
+        undefinedSymbol.declarations = [];
         const argumentsSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Transient, "arguments");
 
         const checker: TypeChecker = {
@@ -141,9 +142,6 @@ namespace ts {
         let globalRegExpType: ObjectType;
         let globalTemplateStringsArrayType: ObjectType;
         let globalESSymbolType: ObjectType;
-        let jsxElementType: ObjectType;
-        /** Lazily loaded, use getJsxIntrinsicElementType() */
-        let jsxIntrinsicElementsType: ObjectType;
         let globalIterableType: GenericType;
         let globalIteratorType: GenericType;
         let globalIterableIteratorType: GenericType;
@@ -208,12 +206,17 @@ namespace ts {
             }
         };
 
+        let jsxElementType: ObjectType;
+        /** Things we lazy load from the JSX namespace */
+        const jsxTypes: Map<ObjectType> = {};
         const JsxNames = {
             JSX: "JSX",
             IntrinsicElements: "IntrinsicElements",
             ElementClass: "ElementClass",
             ElementAttributesPropertyNameContainer: "ElementAttributesProperty",
-            Element: "Element"
+            Element: "Element",
+            IntrinsicAttributes: "IntrinsicAttributes",
+            IntrinsicClassAttributes: "IntrinsicClassAttributes"
         };
 
         const subtypeRelation: Map<RelationComparisonResult> = {};
@@ -232,6 +235,10 @@ namespace ts {
             ResolvedReturnType
         }
 
+        const builtinGlobals: SymbolTable = {
+            [undefinedSymbol.name]: undefinedSymbol
+        };
+
         initializeTypeChecker();
 
         return checker;
@@ -358,6 +365,24 @@ namespace ts {
             }
         }
 
+        function addToSymbolTable(target: SymbolTable, source: SymbolTable, message: DiagnosticMessage) {
+            for (const id in source) {
+                if (hasProperty(source, id)) {
+                    if (hasProperty(target, id)) {
+                        // Error on redeclarations
+                        forEach(target[id].declarations, addDeclarationDiagnostic(id, message));
+                    }
+                    else {
+                        target[id] = source[id];
+                    }
+                }
+            }
+
+            function addDeclarationDiagnostic(id: string, message: DiagnosticMessage) {
+                return (declaration: Declaration) => diagnostics.add(createDiagnosticForNode(declaration, message, id));
+            }
+        }
+
         function getSymbolLinks(symbol: Symbol): SymbolLinks {
             if (symbol.flags & SymbolFlags.Transient) return <TransientSymbol>symbol;
             const id = getSymbolId(symbol);
@@ -377,6 +402,14 @@ namespace ts {
             return node.kind === SyntaxKind.SourceFile && !isExternalOrCommonJsModule(<SourceFile>node);
         }
 
+        /** Is this type one of the apparent types created from the primitive types. */
+        function isPrimitiveApparentType(type: Type): boolean {
+            return type === globalStringType ||
+                type === globalNumberType ||
+                type === globalBooleanType ||
+                type === globalESSymbolType;
+        }
+
         function getSymbol(symbols: SymbolTable, name: string, meaning: SymbolFlags): Symbol {
             if (meaning && hasProperty(symbols, name)) {
                 const symbol = symbols[name];
@@ -1093,39 +1126,81 @@ namespace ts {
             return links.resolvedExports || (links.resolvedExports = getExportsForModule(moduleSymbol));
         }
 
-        function extendExportSymbols(target: SymbolTable, source: SymbolTable) {
+        interface ExportCollisionTracker {
+            specifierText: string;
+            exportsWithDuplicate: ExportDeclaration[];
+        }
+
+        /**
+         * Extends one symbol table with another while collecting information on name collisions for error message generation into the `lookupTable` argument
+         * Not passing `lookupTable` and `exportNode` disables this collection, and just extends the tables
+         */
+        function extendExportSymbols(target: SymbolTable, source: SymbolTable, lookupTable?: Map<ExportCollisionTracker>, exportNode?: ExportDeclaration) {
             for (const id in source) {
                 if (id !== "default" && !hasProperty(target, id)) {
                     target[id] = source[id];
+                    if (lookupTable && exportNode) {
+                        lookupTable[id] = {
+                            specifierText: getTextOfNode(exportNode.moduleSpecifier)
+                        } as ExportCollisionTracker;
+                    }
+                }
+                else if (lookupTable && exportNode && id !== "default" && hasProperty(target, id) && resolveSymbol(target[id]) !== resolveSymbol(source[id])) {
+                    if (!lookupTable[id].exportsWithDuplicate) {
+                        lookupTable[id].exportsWithDuplicate = [exportNode];
+                    }
+                    else {
+                        lookupTable[id].exportsWithDuplicate.push(exportNode);
+                    }
                 }
             }
         }
 
         function getExportsForModule(moduleSymbol: Symbol): SymbolTable {
-            let result: SymbolTable;
             const visitedSymbols: Symbol[] = [];
-            visit(moduleSymbol);
-            return result || moduleSymbol.exports;
+            return visit(moduleSymbol) || moduleSymbol.exports;
 
             // The ES6 spec permits export * declarations in a module to circularly reference the module itself. For example,
             // module 'a' can 'export * from "b"' and 'b' can 'export * from "a"' without error.
-            function visit(symbol: Symbol) {
-                if (symbol && symbol.flags & SymbolFlags.HasExports && !contains(visitedSymbols, symbol)) {
-                    visitedSymbols.push(symbol);
-                    if (symbol !== moduleSymbol) {
-                        if (!result) {
-                            result = cloneSymbolTable(moduleSymbol.exports);
-                        }
-                        extendExportSymbols(result, symbol.exports);
-                    }
-                    // All export * declarations are collected in an __export symbol by the binder
-                    const exportStars = symbol.exports["__export"];
-                    if (exportStars) {
-                        for (const node of exportStars.declarations) {
-                            visit(resolveExternalModuleName(node, (<ExportDeclaration>node).moduleSpecifier));
-                        }
-                    }
+            function visit(symbol: Symbol): SymbolTable {
+                if (!(symbol && symbol.flags & SymbolFlags.HasExports && !contains(visitedSymbols, symbol))) {
+                    return;
                 }
+                visitedSymbols.push(symbol);
+                const symbols = cloneSymbolTable(symbol.exports);
+                // All export * declarations are collected in an __export symbol by the binder
+                const exportStars = symbol.exports["__export"];
+                if (exportStars) {
+                    const nestedSymbols: SymbolTable = {};
+                    const lookupTable: Map<ExportCollisionTracker> = {};
+                    for (const node of exportStars.declarations) {
+                        const resolvedModule = resolveExternalModuleName(node, (node as ExportDeclaration).moduleSpecifier);
+                        const exportedSymbols = visit(resolvedModule);
+                        extendExportSymbols(
+                            nestedSymbols,
+                            exportedSymbols,
+                            lookupTable,
+                            node as ExportDeclaration
+                        );
+                    }
+                    for (const id in lookupTable) {
+                        const { exportsWithDuplicate } = lookupTable[id];
+                        // It's not an error if the file with multiple `export *`s with duplicate names exports a member with that name itself
+                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || hasProperty(symbols, id)) {
+                            continue;
+                        }
+                        for (const node of exportsWithDuplicate) {
+                            diagnostics.add(createDiagnosticForNode(
+                                node,
+                                Diagnostics.Module_0_has_already_exported_a_member_named_1_Consider_explicitly_re_exporting_to_resolve_the_ambiguity,
+                                lookupTable[id].specifierText,
+                                id
+                            ));
+                        }
+                    }
+                    extendExportSymbols(symbols, nestedSymbols);
+                }
+                return symbols;
             }
         }
 
@@ -1519,9 +1594,9 @@ namespace ts {
             return result;
         }
 
-        function signatureToString(signature: Signature, enclosingDeclaration?: Node, flags?: TypeFormatFlags): string {
+        function signatureToString(signature: Signature, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): string {
             const writer = getSingleLineStringWriter();
-            getSymbolDisplayBuilder().buildSignatureDisplay(signature, writer, enclosingDeclaration, flags);
+            getSymbolDisplayBuilder().buildSignatureDisplay(signature, writer, enclosingDeclaration, flags, kind);
             const result = writer.string();
             releaseStringWriter(writer);
 
@@ -1873,7 +1948,7 @@ namespace ts {
                             if (flags & TypeFormatFlags.InElementType) {
                                 writePunctuation(writer, SyntaxKind.OpenParenToken);
                             }
-                            buildSignatureDisplay(resolved.callSignatures[0], writer, enclosingDeclaration, globalFlagsToPass | TypeFormatFlags.WriteArrowStyleSignature, symbolStack);
+                            buildSignatureDisplay(resolved.callSignatures[0], writer, enclosingDeclaration, globalFlagsToPass | TypeFormatFlags.WriteArrowStyleSignature, /*kind*/ undefined, symbolStack);
                             if (flags & TypeFormatFlags.InElementType) {
                                 writePunctuation(writer, SyntaxKind.CloseParenToken);
                             }
@@ -1885,7 +1960,7 @@ namespace ts {
                             }
                             writeKeyword(writer, SyntaxKind.NewKeyword);
                             writeSpace(writer);
-                            buildSignatureDisplay(resolved.constructSignatures[0], writer, enclosingDeclaration, globalFlagsToPass | TypeFormatFlags.WriteArrowStyleSignature, symbolStack);
+                            buildSignatureDisplay(resolved.constructSignatures[0], writer, enclosingDeclaration, globalFlagsToPass | TypeFormatFlags.WriteArrowStyleSignature, /*kind*/ undefined, symbolStack);
                             if (flags & TypeFormatFlags.InElementType) {
                                 writePunctuation(writer, SyntaxKind.CloseParenToken);
                             }
@@ -1899,15 +1974,12 @@ namespace ts {
                     writer.writeLine();
                     writer.increaseIndent();
                     for (const signature of resolved.callSignatures) {
-                        buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, symbolStack);
+                        buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, /*kind*/ undefined, symbolStack);
                         writePunctuation(writer, SyntaxKind.SemicolonToken);
                         writer.writeLine();
                     }
                     for (const signature of resolved.constructSignatures) {
-                        writeKeyword(writer, SyntaxKind.NewKeyword);
-                        writeSpace(writer);
-
-                        buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, symbolStack);
+                        buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, SignatureKind.Construct, symbolStack);
                         writePunctuation(writer, SyntaxKind.SemicolonToken);
                         writer.writeLine();
                     }
@@ -1948,7 +2020,7 @@ namespace ts {
                                 if (p.flags & SymbolFlags.Optional) {
                                     writePunctuation(writer, SyntaxKind.QuestionToken);
                                 }
-                                buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, symbolStack);
+                                buildSignatureDisplay(signature, writer, enclosingDeclaration, globalFlagsToPass, /*kind*/ undefined, symbolStack);
                                 writePunctuation(writer, SyntaxKind.SemicolonToken);
                                 writer.writeLine();
                             }
@@ -2068,7 +2140,12 @@ namespace ts {
                 buildTypeDisplay(returnType, writer, enclosingDeclaration, flags, symbolStack);
             }
 
-            function buildSignatureDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, symbolStack?: Symbol[]) {
+            function buildSignatureDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind, symbolStack?: Symbol[]) {
+                if (kind === SignatureKind.Construct) {
+                    writeKeyword(writer, SyntaxKind.NewKeyword);
+                    writeSpace(writer);
+                }
+
                 if (signature.target && (flags & TypeFormatFlags.WriteTypeArgumentsOfSignature)) {
                     // Instantiated signature, write type arguments instead
                     // This is achieved by passing in the mapper separately
@@ -2936,10 +3013,6 @@ namespace ts {
             return type.resolvedBaseConstructorType;
         }
 
-        function hasClassBaseType(type: InterfaceType): boolean {
-            return !!forEach(getBaseTypes(type), t => !!(t.symbol.flags & SymbolFlags.Class));
-        }
-
         function getBaseTypes(type: InterfaceType): ObjectType[] {
             const isClass = type.symbol.flags & SymbolFlags.Class;
             const isInterface = type.symbol.flags & SymbolFlags.Interface;
@@ -3373,11 +3446,11 @@ namespace ts {
         }
 
         function getDefaultConstructSignatures(classType: InterfaceType): Signature[] {
-            if (!hasClassBaseType(classType)) {
-                return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
-            }
             const baseConstructorType = getBaseConstructorTypeOfClass(classType);
             const baseSignatures = getSignaturesOfType(baseConstructorType, SignatureKind.Construct);
+            if (baseSignatures.length === 0) {
+                return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
+            }
             const baseTypeNode = getBaseTypeNodeOfClass(classType);
             const typeArguments = map(baseTypeNode.typeArguments, getTypeFromTypeNode);
             const typeArgCount = typeArguments ? typeArguments.length : 0;
@@ -3595,7 +3668,7 @@ namespace ts {
             return <ResolvedType>type;
         }
 
-        // Return properties of an object type or an empty array for other types
+        /** Return properties of an object type or an empty array for other types */
         function getPropertiesOfObjectType(type: Type): Symbol[] {
             if (type.flags & TypeFlags.ObjectType) {
                 return resolveStructuredTypeMembers(<ObjectType>type).properties;
@@ -3603,8 +3676,8 @@ namespace ts {
             return emptyArray;
         }
 
-        // If the given type is an object type and that type has a property by the given name,
-        // return the symbol for that property.Otherwise return undefined.
+        /** If the given type is an object type and that type has a property by the given name,
+         * return the symbol for that property. Otherwise return undefined. */
         function getPropertyOfObjectType(type: Type, name: string): Symbol {
             if (type.flags & TypeFlags.ObjectType) {
                 const resolved = resolveStructuredTypeMembers(<ObjectType>type);
@@ -5395,20 +5468,26 @@ namespace ts {
 
                 outer: for (const t of targetSignatures) {
                     if (!t.hasStringLiterals || target.flags & TypeFlags.FromSignature) {
-                        let localErrors = reportErrors;
-                        const checkedAbstractAssignability = false;
+                        // Only elaborate errors from the first failure
+                        let shouldElaborateErrors = reportErrors;
                         for (const s of sourceSignatures) {
                             if (!s.hasStringLiterals || source.flags & TypeFlags.FromSignature) {
-                                const related = signatureRelatedTo(s, t, localErrors);
+                                const related = signatureRelatedTo(s, t, shouldElaborateErrors);
                                 if (related) {
                                     result &= related;
                                     errorInfo = saveErrorInfo;
                                     continue outer;
                                 }
-                                // Only report errors from the first failure
-                                localErrors = false;
+                                shouldElaborateErrors = false;
                             }
                         }
+                        // don't elaborate the primitive apparent types (like Number) 
+                        // because the actual primitives will have already been reported.
+                        if (shouldElaborateErrors && !isPrimitiveApparentType(source)) {
+                            reportError(Diagnostics.Type_0_provides_no_match_for_the_signature_1,
+                                typeToString(source),
+                                signatureToString(t, /*enclosingDeclaration*/ undefined, /*flags*/ undefined, kind));
+                        }
                         return Ternary.False;
                     }
                 }
@@ -6038,14 +6117,25 @@ namespace ts {
             function inferFromTypes(source: Type, target: Type) {
                 if (source.flags & TypeFlags.Union && target.flags & TypeFlags.Union ||
                     source.flags & TypeFlags.Intersection && target.flags & TypeFlags.Intersection) {
-                    // Source and target are both unions or both intersections. To improve the quality of
-                    // inferences we first reduce the types by removing constituents that are identically
-                    // matched by a constituent in the other type. For example, when inferring from
-                    // 'string | string[]' to 'string | T', we reduce the types to 'string[]' and 'T'.
-                    const reducedSource = reduceUnionOrIntersectionType(<UnionOrIntersectionType>source, <UnionOrIntersectionType>target);
-                    const reducedTarget = reduceUnionOrIntersectionType(<UnionOrIntersectionType>target, <UnionOrIntersectionType>source);
-                    source = reducedSource;
-                    target = reducedTarget;
+                    // Source and target are both unions or both intersections. First, find each
+                    // target constituent type that has an identically matching source constituent
+                    // type, and for each such target constituent type infer from the type to itself.
+                    // When inferring from a type to itself we effectively find all type parameter
+                    // occurrences within that type and infer themselves as their type arguments.
+                    let matchingTypes: Type[];
+                    for (const t of (<UnionOrIntersectionType>target).types) {
+                        if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>source).types)) {
+                            (matchingTypes || (matchingTypes = [])).push(t);
+                            inferFromTypes(t, t);
+                        }
+                    }
+                    // Next, to improve the quality of inferences, reduce the source and target types by
+                    // removing the identically matched constituents. For example, when inferring from
+                    // 'string | string[]' to 'string | T' we reduce the types to 'string[]' and 'T'.
+                    if (matchingTypes) {
+                        source = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>source, matchingTypes);
+                        target = removeTypesFromUnionOrIntersection(<UnionOrIntersectionType>target, matchingTypes);
+                    }
                 }
                 if (target.flags & TypeFlags.TypeParameter) {
                     // If target is a type parameter, make an inference, unless the source type contains
@@ -6129,9 +6219,12 @@ namespace ts {
                 }
                 else {
                     source = getApparentType(source);
-                    if (source.flags & TypeFlags.ObjectType && (target.flags & (TypeFlags.Reference | TypeFlags.Tuple) ||
-                        (target.flags & TypeFlags.Anonymous) && target.symbol && target.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class))) {
-                        // If source is an object type, and target is a type reference, a tuple type, the type of a method, or a type literal, infer from members
+                    if (source.flags & TypeFlags.ObjectType && (
+                        target.flags & TypeFlags.Reference && (<TypeReference>target).typeArguments ||
+                        target.flags & TypeFlags.Tuple ||
+                        target.flags & TypeFlags.Anonymous && target.symbol && target.symbol.flags & (SymbolFlags.Method | SymbolFlags.TypeLiteral | SymbolFlags.Class))) {
+                        // If source is an object type, and target is a type reference with type arguments, a tuple type,
+                        // the type of a method, or a type literal, infer from members
                         if (isInProcess(source, target)) {
                             return;
                         }
@@ -6204,9 +6297,9 @@ namespace ts {
             }
         }
 
-        function typeIdenticalToSomeType(source: Type, target: UnionOrIntersectionType): boolean {
-            for (const t of target.types) {
-                if (isTypeIdenticalTo(source, t)) {
+        function typeIdenticalToSomeType(type: Type, types: Type[]): boolean {
+            for (const t of types) {
+                if (isTypeIdenticalTo(t, type)) {
                     return true;
                 }
             }
@@ -6214,29 +6307,17 @@ namespace ts {
         }
 
         /**
-         * Return the reduced form of the source type. This type is computed by by removing all source
-         * constituents that have an identical match in the target type.
+         * Return a new union or intersection type computed by removing a given set of types
+         * from a given union or intersection type.
          */
-        function reduceUnionOrIntersectionType(source: UnionOrIntersectionType, target: UnionOrIntersectionType) {
-            let sourceTypes = source.types;
-            let sourceIndex = 0;
-            let modified = false;
-            while (sourceIndex < sourceTypes.length) {
-                if (typeIdenticalToSomeType(sourceTypes[sourceIndex], target)) {
-                    if (!modified) {
-                        sourceTypes = sourceTypes.slice(0);
-                        modified = true;
-                    }
-                    sourceTypes.splice(sourceIndex, 1);
-                }
-                else {
-                    sourceIndex++;
+        function removeTypesFromUnionOrIntersection(type: UnionOrIntersectionType, typesToRemove: Type[]) {
+            const reducedTypes: Type[] = [];
+            for (const t of type.types) {
+                if (!typeIdenticalToSomeType(t, typesToRemove)) {
+                    reducedTypes.push(t);
                 }
             }
-            if (modified) {
-                return source.flags & TypeFlags.Union ? getUnionType(sourceTypes, /*noSubtypeReduction*/ true) : getIntersectionType(sourceTypes);
-            }
-            return source;
+            return type.flags & TypeFlags.Union ? getUnionType(reducedTypes, /*noSubtypeReduction*/ true) : getIntersectionType(reducedTypes);
         }
 
         function getInferenceCandidates(context: InferenceContext, index: number): Type[] {
@@ -7820,12 +7901,11 @@ namespace ts {
             return type;
         }
 
-        /// Returns the type JSX.IntrinsicElements. May return `unknownType` if that type is not present.
-        function getJsxIntrinsicElementsType() {
-            if (!jsxIntrinsicElementsType) {
-                jsxIntrinsicElementsType = getExportedTypeFromNamespace(JsxNames.JSX, JsxNames.IntrinsicElements) || unknownType;
+        function getJsxType(name: string) {
+            if (jsxTypes[name] === undefined) {
+                return jsxTypes[name] = getExportedTypeFromNamespace(JsxNames.JSX, name) || unknownType;
             }
-            return jsxIntrinsicElementsType;
+            return jsxTypes[name];
         }
 
         /// Given a JSX opening element or self-closing element, return the symbol of the property that the tag name points to if
@@ -7848,7 +7928,7 @@ namespace ts {
             return links.resolvedSymbol;
 
             function lookupIntrinsicTag(node: JsxOpeningLikeElement | JsxClosingElement): Symbol {
-                const intrinsicElementsType = getJsxIntrinsicElementsType();
+                const intrinsicElementsType = getJsxType(JsxNames.IntrinsicElements);
                 if (intrinsicElementsType !== unknownType) {
                     // Property case
                     const intrinsicProp = getPropertyOfType(intrinsicElementsType, (<Identifier>node.tagName).text);
@@ -7880,7 +7960,7 @@ namespace ts {
 
                 // Look up the value in the current scope
                 if (valueSymbol && valueSymbol !== unknownSymbol) {
-                    links.jsxFlags |= JsxFlags.ClassElement;
+                    links.jsxFlags |= JsxFlags.ValueElement;
                     if (valueSymbol.flags & SymbolFlags.Alias) {
                         markAliasSymbolAsReferenced(valueSymbol);
                     }
@@ -7909,7 +7989,7 @@ namespace ts {
         function getJsxElementInstanceType(node: JsxOpeningLikeElement) {
             // There is no such thing as an instance type for a non-class element. This
             // line shouldn't be hit.
-            Debug.assert(!!(getNodeLinks(node).jsxFlags & JsxFlags.ClassElement), "Should not call getJsxElementInstanceType on non-class Element");
+            Debug.assert(!!(getNodeLinks(node).jsxFlags & JsxFlags.ValueElement), "Should not call getJsxElementInstanceType on non-class Element");
 
             const classSymbol = getJsxElementTagSymbol(node);
             if (classSymbol === unknownSymbol) {
@@ -7936,15 +8016,7 @@ namespace ts {
                 }
             }
 
-            const returnType = getUnionType(signatures.map(getReturnTypeOfSignature));
-
-            // Issue an error if this return type isn't assignable to JSX.ElementClass
-            const elemClassType = getJsxGlobalElementClassType();
-            if (elemClassType) {
-                checkTypeRelatedTo(returnType, elemClassType, assignableRelation, node, Diagnostics.JSX_element_type_0_is_not_a_constructor_function_for_JSX_elements);
-            }
-
-            return returnType;
+            return getUnionType(signatures.map(getReturnTypeOfSignature));
         }
 
         /// e.g. "props" for React.d.ts,
@@ -7993,9 +8065,31 @@ namespace ts {
             if (!links.resolvedJsxType) {
                 const sym = getJsxElementTagSymbol(node);
 
-                if (links.jsxFlags & JsxFlags.ClassElement) {
+                if (links.jsxFlags & JsxFlags.ValueElement) {
+                    // Get the element instance type (the result of newing or invoking this tag)
                     const elemInstanceType = getJsxElementInstanceType(node);
 
+                    // Is this is a stateless function component? See if its single signature is
+                    // assignable to the JSX Element Type
+                    const callSignature = getSingleCallSignature(getTypeOfSymbol(sym));
+                    const callReturnType = callSignature && getReturnTypeOfSignature(callSignature);
+                    let paramType = callReturnType && (callSignature.parameters.length === 0 ? emptyObjectType : getTypeOfSymbol(callSignature.parameters[0]));
+                    if (callReturnType && isTypeAssignableTo(callReturnType, jsxElementType) && (paramType.flags & TypeFlags.ObjectType)) {
+                        // Intersect in JSX.IntrinsicAttributes if it exists
+                        const intrinsicAttributes = getJsxType(JsxNames.IntrinsicAttributes);
+                        if (intrinsicAttributes !== unknownType) {
+                            paramType = intersectTypes(intrinsicAttributes, paramType);
+                        }
+                        return paramType;
+                    }
+
+                    // Issue an error if this return type isn't assignable to JSX.ElementClass
+                    const elemClassType = getJsxGlobalElementClassType();
+                    if (elemClassType) {
+                        checkTypeRelatedTo(elemInstanceType, elemClassType, assignableRelation, node, Diagnostics.JSX_element_type_0_is_not_a_constructor_function_for_JSX_elements);
+                    }
+
+
                     if (isTypeAny(elemInstanceType)) {
                         return links.resolvedJsxType = elemInstanceType;
                     }
@@ -8017,14 +8111,36 @@ namespace ts {
                             return links.resolvedJsxType = emptyObjectType;
                         }
                         else if (isTypeAny(attributesType) || (attributesType === unknownType)) {
+                            // Props is of type 'any' or unknown
                             return links.resolvedJsxType = attributesType;
                         }
                         else if (!(attributesType.flags & TypeFlags.ObjectType)) {
+                            // Props is not an object type
                             error(node.tagName, Diagnostics.JSX_element_attributes_type_0_must_be_an_object_type, typeToString(attributesType));
                             return links.resolvedJsxType = anyType;
                         }
                         else {
-                            return links.resolvedJsxType = attributesType;
+                            // Normal case -- add in IntrinsicClassElements<T> and IntrinsicElements
+                            let apparentAttributesType = attributesType;
+                            const intrinsicClassAttribs = getJsxType(JsxNames.IntrinsicClassAttributes);
+                            if (intrinsicClassAttribs !== unknownType) {
+                                const typeParams = getLocalTypeParametersOfClassOrInterfaceOrTypeAlias(intrinsicClassAttribs.symbol);
+                                if (typeParams) {
+                                    if (typeParams.length === 1) {
+                                        apparentAttributesType = intersectTypes(createTypeReference(<GenericType>intrinsicClassAttribs, [elemInstanceType]), apparentAttributesType);
+                                    }
+                                }
+                                else {
+                                    apparentAttributesType = intersectTypes(attributesType, intrinsicClassAttribs);
+                                }
+                            }
+
+                            const intrinsicAttribs = getJsxType(JsxNames.IntrinsicAttributes);
+                            if (intrinsicAttribs !== unknownType) {
+                                apparentAttributesType = intersectTypes(intrinsicAttribs, apparentAttributesType);
+                            }
+
+                            return links.resolvedJsxType = apparentAttributesType;
                         }
                     }
                 }
@@ -8063,7 +8179,7 @@ namespace ts {
 
         /// Returns all the properties of the Jsx.IntrinsicElements interface
         function getJsxIntrinsicTagNames(): Symbol[] {
-            const intrinsics = getJsxIntrinsicElementsType();
+            const intrinsics = getJsxType(JsxNames.IntrinsicElements);
             return intrinsics ? getPropertiesOfType(intrinsics) : emptyArray;
         }
 
@@ -9810,7 +9926,7 @@ namespace ts {
             return aggregatedTypes;
         }
 
-        /* 
+        /*
          *TypeScript Specification 1.0 (6.3) - July 2014
          * An explicitly typed function whose return type isn't the Void or the Any type
          * must have at least one return statement somewhere in its body.
@@ -9823,31 +9939,39 @@ namespace ts {
             }
 
             // Functions with with an explicitly specified 'void' or 'any' return type don't need any return expressions.
-            if (returnType && (returnType === voidType || isTypeAny(returnType))) {
-                return;
-            }
-
-            // if return type is not specified then we'll do the check only if 'noImplicitReturns' option is set
-            if (!returnType && !compilerOptions.noImplicitReturns) {
+            if (returnType === voidType || isTypeAny(returnType)) {
                 return;
             }
 
             // If all we have is a function signature, or an arrow function with an expression body, then there is nothing to check.
-            // also if HasImplicitReturnValue flags is not set this means that all codepaths in function body end with return of throw
+            // also if HasImplicitReturn flag is not set this means that all codepaths in function body end with return or throw
             if (nodeIsMissing(func.body) || func.body.kind !== SyntaxKind.Block || !(func.flags & NodeFlags.HasImplicitReturn)) {
                 return;
             }
 
-            if (!returnType || func.flags & NodeFlags.HasExplicitReturn) {
-                if (compilerOptions.noImplicitReturns) {
-                    error(func.type || func, Diagnostics.Not_all_code_paths_return_a_value);
-                }
-            }
-            else {
-                // This function does not conform to the specification.
-                // NOTE: having returnType !== undefined is a precondition for entering this branch so func.type will always be present 
+            const hasExplicitReturn = func.flags & NodeFlags.HasExplicitReturn;
+
+            if (returnType && !hasExplicitReturn) {
+                // minimal check: function has syntactic return type annotation and no explicit return statements in the body
+                // this function does not conform to the specification.
+                // NOTE: having returnType !== undefined is a precondition for entering this branch so func.type will always be present
                 error(func.type, Diagnostics.A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value);
             }
+            else if (compilerOptions.noImplicitReturns) {
+                if (!returnType) {
+                    // If return type annotation is omitted check if function has any explicit return statements.
+                    // If it does not have any - its inferred return type is void - don't do any checks.
+                    // Otherwise get inferred return type from function body and report error only if it is not void / anytype
+                    const inferredReturnType = hasExplicitReturn
+                        ? getReturnTypeOfSignature(getSignatureFromDeclaration(func))
+                        : voidType;
+
+                    if (inferredReturnType === voidType || isTypeAny(inferredReturnType)) {
+                        return;
+                    }
+                }
+                error(func.type || func, Diagnostics.Not_all_code_paths_return_a_value);
+            }
         }
 
         function checkFunctionExpressionOrObjectLiteralMethod(node: FunctionExpression | MethodDeclaration, contextualMapper?: TypeMapper): Type {
@@ -11400,7 +11524,9 @@ namespace ts {
                         seen = c === node;
                     }
                 });
-                if (subsequentNode) {
+                // We may be here because of some extra junk between overloads that could not be parsed into a valid node.
+                // In this case the subsequent node is not really consecutive (.pos !== node.end), and we must ignore it here.
+                if (subsequentNode && subsequentNode.pos === node.end) {
                     if (subsequentNode.kind === node.kind) {
                         const errorNode: Node = (<FunctionLikeDeclaration>subsequentNode).name || subsequentNode;
                         // TODO(jfreeman): These are methods, so handle computed name case
@@ -11873,6 +11999,9 @@ namespace ts {
                 return unknownType;
             }
 
+            // If the Promise constructor, resolved locally, is an alias symbol we should mark it as referenced.
+            checkReturnTypeAnnotationAsExpression(node);
+
             // Validate the promise constructor type.
             const promiseConstructorType = getTypeOfSymbol(promiseConstructor);
             if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, node, Diagnostics.Type_0_is_not_a_valid_async_function_return_type)) {
@@ -11881,11 +12010,11 @@ namespace ts {
 
             // Verify there is no local declaration that could collide with the promise constructor.
             const promiseName = getEntityNameFromTypeNode(node.type);
-            const root = getFirstIdentifier(promiseName);
-            const rootSymbol = getSymbol(node.locals, root.text, SymbolFlags.Value);
+            const promiseNameOrNamespaceRoot = getFirstIdentifier(promiseName);
+            const rootSymbol = getSymbol(node.locals, promiseNameOrNamespaceRoot.text, SymbolFlags.Value);
             if (rootSymbol) {
                 error(rootSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
-                    root.text,
+                    promiseNameOrNamespaceRoot.text,
                     getFullyQualifiedName(promiseConstructor));
                 return unknownType;
             }
@@ -11969,24 +12098,12 @@ namespace ts {
           * Checks the type annotation of an accessor declaration or property declaration as
           * an expression if it is a type reference to a type with a value declaration.
           */
-        function checkTypeAnnotationAsExpression(node: AccessorDeclaration | PropertyDeclaration | ParameterDeclaration | MethodDeclaration) {
-            switch (node.kind) {
-                case SyntaxKind.PropertyDeclaration:
-                    checkTypeNodeAsExpression((<PropertyDeclaration>node).type);
-                    break;
-                case SyntaxKind.Parameter:
-                    checkTypeNodeAsExpression((<ParameterDeclaration>node).type);
-                    break;
-                case SyntaxKind.MethodDeclaration:
-                    checkTypeNodeAsExpression((<MethodDeclaration>node).type);
-                    break;
-                case SyntaxKind.GetAccessor:
-                    checkTypeNodeAsExpression((<AccessorDeclaration>node).type);
-                    break;
-                case SyntaxKind.SetAccessor:
-                    checkTypeNodeAsExpression(getSetAccessorTypeAnnotationNode(<AccessorDeclaration>node));
-                    break;
-            }
+        function checkTypeAnnotationAsExpression(node: VariableLikeDeclaration) {
+            checkTypeNodeAsExpression((<PropertyDeclaration>node).type);
+        }
+
+        function checkReturnTypeAnnotationAsExpression(node: FunctionLikeDeclaration) {
+            checkTypeNodeAsExpression(node.type);
         }
 
         /** Checks the type annotation of the parameters of a function/method or the constructor of a class as expressions */
@@ -12024,11 +12141,12 @@ namespace ts {
                         break;
 
                     case SyntaxKind.MethodDeclaration:
-                        checkParameterTypeAnnotationsAsExpressions(<FunctionLikeDeclaration>node);
-                    // fall-through
-
-                    case SyntaxKind.SetAccessor:
                     case SyntaxKind.GetAccessor:
+                    case SyntaxKind.SetAccessor:
+                        checkParameterTypeAnnotationsAsExpressions(<FunctionLikeDeclaration>node);
+                        checkReturnTypeAnnotationAsExpression(<FunctionLikeDeclaration>node);
+                        break;
+
                     case SyntaxKind.PropertyDeclaration:
                     case SyntaxKind.Parameter:
                         checkTypeAnnotationAsExpression(<PropertyDeclaration | ParameterDeclaration>node);
@@ -12078,8 +12196,8 @@ namespace ts {
                 const symbol = getSymbolOfNode(node);
                 const localSymbol = node.localSymbol || symbol;
 
-                // Since the javascript won't do semantic analysis like typescript, 
-                // if the javascript file comes before the typescript file and both contain same name functions, 
+                // Since the javascript won't do semantic analysis like typescript,
+                // if the javascript file comes before the typescript file and both contain same name functions,
                 // checkFunctionOrConstructorSymbol wouldn't be called if we didnt ignore javascript function.
                 const firstDeclaration = forEach(localSymbol.declarations,
                     // Get first non javascript function declaration
@@ -14056,8 +14174,29 @@ namespace ts {
                     const declaration = getDeclarationOfAliasSymbol(exportEqualsSymbol) || exportEqualsSymbol.valueDeclaration;
                     error(declaration, Diagnostics.An_export_assignment_cannot_be_used_in_a_module_with_other_exported_elements);
                 }
+                // Checks for export * conflicts
+                const exports = getExportsOfModule(moduleSymbol);
+                for (const id in exports) {
+                    if (id === "__export") {
+                        continue;
+                    }
+                    const { declarations, flags } = exports[id];
+                    // ECMA262: 15.2.1.1 It is a Syntax Error if the ExportedNames of ModuleItemList contains any duplicate entries. (TS Exceptions: namespaces, function overloads, enums, and interfaces)
+                    if (!(flags & (SymbolFlags.Namespace | SymbolFlags.Interface | SymbolFlags.Enum)) && declarations.length > 1) {
+                        const exportedDeclarations: Declaration[] = filter(declarations, isNotOverload);
+                        if (exportedDeclarations.length > 1) {
+                            for (const declaration of exportedDeclarations) {
+                                diagnostics.add(createDiagnosticForNode(declaration, Diagnostics.Cannot_redeclare_exported_variable_0, id));
+                            }
+                        }
+                    }
+                }
                 links.exportsChecked = true;
             }
+
+            function isNotOverload(declaration: Declaration): boolean {
+                return declaration.kind !== SyntaxKind.FunctionDeclaration || !!(declaration as FunctionDeclaration).body;
+            }
         }
 
         function checkTypePredicate(node: TypePredicateNode) {
@@ -14329,6 +14468,7 @@ namespace ts {
                 emitExtends = false;
                 emitDecorate = false;
                 emitParam = false;
+                emitAwaiter = false;
                 potentialThisCollisions.length = 0;
 
                 forEach(node.statements, checkSourceElement);
@@ -15191,10 +15331,12 @@ namespace ts {
                 }
             });
 
+            // Setup global builtins
+            addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
+
             getSymbolLinks(undefinedSymbol).type = undefinedType;
             getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments");
             getSymbolLinks(unknownSymbol).type = unknownType;
-            globals[undefinedSymbol.name] = undefinedSymbol;
 
             // Initialize special types
             globalArrayType = <GenericType>getGlobalType("Array", /*arity*/ 1);
@@ -15888,13 +16030,27 @@ namespace ts {
             if (forInOrOfStatement.initializer.kind === SyntaxKind.VariableDeclarationList) {
                 const variableList = <VariableDeclarationList>forInOrOfStatement.initializer;
                 if (!checkGrammarVariableDeclarationList(variableList)) {
-                    if (variableList.declarations.length > 1) {
+                    const declarations = variableList.declarations;
+
+                    // declarations.length can be zero if there is an error in variable declaration in for-of or for-in
+                    // See http://www.ecma-international.org/ecma-262/6.0/#sec-for-in-and-for-of-statements for details
+                    // For example:
+                    //      var let = 10;
+                    //      for (let of [1,2,3]) {} // this is invalid ES6 syntax
+                    //      for (let in [1,2,3]) {} // this is invalid ES6 syntax
+                    // We will then want to skip on grammar checking on variableList declaration
+                    if (!declarations.length) {
+                        return false;
+                    }
+
+                    if (declarations.length > 1) {
                         const diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement
                             ? Diagnostics.Only_a_single_variable_declaration_is_allowed_in_a_for_in_statement
                             : Diagnostics.Only_a_single_variable_declaration_is_allowed_in_a_for_of_statement;
                         return grammarErrorOnFirstToken(variableList.declarations[1], diagnostic);
                     }
-                    const firstDeclaration = variableList.declarations[0];
+                    const firstDeclaration = declarations[0];
+
                     if (firstDeclaration.initializer) {
                         const diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement
                             ? Diagnostics.The_variable_declaration_of_a_for_in_statement_cannot_have_an_initializer
@@ -16093,7 +16249,7 @@ namespace ts {
                 }
             }
 
-            const checkLetConstNames = languageVersion >= ScriptTarget.ES6 && (isLet(node) || isConst(node));
+            const checkLetConstNames = (isLet(node) || isConst(node));
 
             // 1. LexicalDeclaration : LetOrConst BindingList ;
             // It is a Syntax Error if the BoundNames of BindingList contains "let".
@@ -16107,7 +16263,7 @@ namespace ts {
 
         function checkGrammarNameInLetOrConstDeclarations(name: Identifier | BindingPattern): boolean {
             if (name.kind === SyntaxKind.Identifier) {
-                if ((<Identifier>name).text === "let") {
+                if ((<Identifier>name).originalKeywordKind === SyntaxKind.LetKeyword) {
                     return grammarErrorOnNode(name, Diagnostics.let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations);
                 }
             }
@@ -16235,11 +16391,17 @@ namespace ts {
                 if (checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_an_interface_must_directly_refer_to_a_built_in_symbol)) {
                     return true;
                 }
+                if (node.initializer) {
+                    return grammarErrorOnNode(node.initializer, Diagnostics.An_interface_property_cannot_have_an_initializer);
+                }
             }
             else if (node.parent.kind === SyntaxKind.TypeLiteral) {
                 if (checkGrammarForNonSymbolComputedProperty(node.name, Diagnostics.A_computed_property_name_in_a_type_literal_must_directly_refer_to_a_built_in_symbol)) {
                     return true;
                 }
+                if (node.initializer) {
+                    return grammarErrorOnNode(node.initializer, Diagnostics.A_type_literal_property_cannot_have_an_initializer);
+                }
             }
 
             if (isInAmbientContext(node) && node.initializer) {

src/compiler/core.ts

@@ -356,6 +356,33 @@ namespace ts {
         return result;
     }
 
+    /**
+     * Reduce the properties of a map.
+     *
+     * @param map The map to reduce
+     * @param callback An aggregation function that is called for each entry in the map
+     * @param initial The initial value for the reduction.
+     */
+    export function reduceProperties<T, U>(map: Map<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
+        let result = initial;
+        if (map) {
+            for (const key in map) {
+                if (hasProperty(map, key)) {
+                    result = callback(result, map[key], String(key));
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Tests whether a value is an array.
+     */
+    export function isArray(value: any): value is any[] {
+        return Array.isArray ? Array.isArray(value) : value instanceof Array;
+    }
+
     export function memoize<T>(callback: () => T): () => T {
         let value: T;
         return () => {

src/compiler/declarationEmitter.ts

@@ -1675,7 +1675,7 @@ namespace ts {
     /* @internal */
     export function writeDeclarationFile(declarationFilePath: string, sourceFiles: SourceFile[], isBundledEmit: boolean, host: EmitHost, resolver: EmitResolver, emitterDiagnostics: DiagnosticCollection) {
         const emitDeclarationResult = emitDeclarations(host, resolver, emitterDiagnostics, declarationFilePath, sourceFiles, isBundledEmit);
-        const emitSkipped = emitDeclarationResult.reportedDeclarationError || host.isEmitBlocked(declarationFilePath);
+        const emitSkipped = emitDeclarationResult.reportedDeclarationError || host.isEmitBlocked(declarationFilePath) || host.getCompilerOptions().noEmit;
         if (!emitSkipped) {
             const declarationOutput = emitDeclarationResult.referencePathsOutput
                 + getDeclarationOutput(emitDeclarationResult.synchronousDeclarationOutput, emitDeclarationResult.moduleElementDeclarationEmitInfo);

src/compiler/diagnosticMessages.json

@@ -783,6 +783,14 @@
         "category": "Error",
         "code": 1245
     },
+    "An interface property cannot have an initializer.": {
+        "category": "Error",
+        "code": 1246
+    },
+    "A type literal property cannot have an initializer.": {
+        "category": "Error",
+        "code": 1247
+    },
 
     "'with' statements are not allowed in an async function block.": {
         "category": "Error",
@@ -836,6 +844,10 @@
         "category": "Error",
         "code": 2307
     },
+    "Module {0} has already exported a member named '{1}'. Consider explicitly re-exporting to resolve the ambiguity.": {
+        "category": "Error",
+        "code": 2308
+    },
     "An export assignment cannot be used in a module with other exported elements.": {
         "category": "Error",
         "code": 2309
@@ -892,6 +904,10 @@
         "category": "Error",
         "code": 2322
     },
+    "Cannot redeclare exported variable '{0}'.": {
+        "category": "Error",
+        "code": 2323
+    },
     "Property '{0}' is missing in type '{1}'.": {
         "category": "Error",
         "code": 2324
@@ -1172,6 +1188,10 @@
         "category": "Error",
         "code": 2396
     },
+    "Declaration name conflicts with built-in global identifier '{0}'.": {
+        "category": "Error",
+        "code": 2397
+    },
     "Duplicate identifier '_this'. Compiler uses variable declaration '_this' to capture 'this' reference.": {
         "category": "Error",
         "code": 2399
@@ -1724,6 +1744,10 @@
         "category": "Error",
         "code": 2657
     },
+    "Type '{0}' provides no match for the signature '{1}'": {
+        "category": "Error",
+        "code": 2658
+    },
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000
@@ -2430,7 +2454,7 @@
     "Not all code paths return a value.": {
         "category": "Error",
         "code": 7030
-    },    
+    },
     "You cannot rename this element.": {
         "category": "Error",
         "code": 8000

src/compiler/parser.ts

@@ -2259,6 +2259,14 @@ namespace ts {
                 property.name = name;
                 property.questionToken = questionToken;
                 property.type = parseTypeAnnotation();
+
+                if (token === SyntaxKind.EqualsToken) {
+                    // Although type literal properties cannot not have initializers, we attempt
+                    // to parse an initializer so we can report in the checker that an interface
+                    // property or type literal property cannot have an initializer.
+                    property.initializer = parseNonParameterInitializer();
+                }
+
                 parseTypeMemberSemicolon();
                 return finishNode(property);
             }
@@ -4902,7 +4910,7 @@ namespace ts {
 
                 if (!decorators) {
                     decorators = <NodeArray<Decorator>>[];
-                    decorators.pos = scanner.getStartPos();
+                    decorators.pos = decoratorStart;
                 }
 
                 const decorator = <Decorator>createNode(SyntaxKind.Decorator, decoratorStart);
@@ -5302,16 +5310,17 @@ namespace ts {
         }
 
         function parseModuleSpecifier(): Expression {
-            // We allow arbitrary expressions here, even though the grammar only allows string
-            // literals.  We check to ensure that it is only a string literal later in the grammar
-            // walker.
-            const result = parseExpression();
-            // Ensure the string being required is in our 'identifier' table.  This will ensure
-            // that features like 'find refs' will look inside this file when search for its name.
-            if (result.kind === SyntaxKind.StringLiteral) {
+            if (token === SyntaxKind.StringLiteral) {
+                const result = parseLiteralNode();
                 internIdentifier((<LiteralExpression>result).text);
+                return result;
+            }
+            else {
+                // We allow arbitrary expressions here, even though the grammar only allows string
+                // literals.  We check to ensure that it is only a string literal later in the grammar
+                // check pass.
+                return parseExpression();
             }
-            return result;
         }
 
         function parseNamespaceImport(): NamespaceImport {
@@ -5428,11 +5437,13 @@ namespace ts {
             // reference comment.
             while (true) {
                 const kind = triviaScanner.scan();
-                if (kind === SyntaxKind.WhitespaceTrivia || kind === SyntaxKind.NewLineTrivia || kind === SyntaxKind.MultiLineCommentTrivia) {
-                    continue;
-                }
                 if (kind !== SyntaxKind.SingleLineCommentTrivia) {
-                    break;
+                    if (isTrivia(kind)) {
+                        continue;
+                    }
+                    else {
+                        break;
+                    }
                 }
 
                 const range = { pos: triviaScanner.getTokenPos(), end: triviaScanner.getTextPos(), kind: triviaScanner.getToken() };

src/compiler/program.ts

@@ -661,19 +661,17 @@ namespace ts {
         }
 
         function getSemanticDiagnosticsForFile(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
-            // For JavaScript files, we don't want to report the normal typescript semantic errors.
-            // Instead, we just report errors for using TypeScript-only constructs from within a
-            // JavaScript file.
-            if (isSourceFileJavaScript(sourceFile)) {
-                return getJavaScriptSemanticDiagnosticsForFile(sourceFile, cancellationToken);
-            }
-
             return runWithCancellationToken(() => {
                 const typeChecker = getDiagnosticsProducingTypeChecker();
 
                 Debug.assert(!!sourceFile.bindDiagnostics);
                 const bindDiagnostics = sourceFile.bindDiagnostics;
-                const checkDiagnostics = typeChecker.getDiagnostics(sourceFile, cancellationToken);
+                // For JavaScript files, we don't want to report the normal typescript semantic errors.
+                // Instead, we just report errors for using TypeScript-only constructs from within a
+                // JavaScript file.
+                const checkDiagnostics = isSourceFileJavaScript(sourceFile) ?
+                    getJavaScriptSemanticDiagnosticsForFile(sourceFile, cancellationToken) :
+                    typeChecker.getDiagnostics(sourceFile, cancellationToken);
                 const fileProcessingDiagnosticsInFile = fileProcessingDiagnostics.getDiagnostics(sourceFile.fileName);
                 const programDiagnosticsInFile = programDiagnostics.getDiagnostics(sourceFile.fileName);
 
@@ -1079,6 +1077,8 @@ namespace ts {
                         const importedFile = findSourceFile(resolution.resolvedFileName, toPath(resolution.resolvedFileName, currentDirectory, getCanonicalFileName), /*isDefaultLib*/ false, file, skipTrivia(file.text, file.imports[i].pos), file.imports[i].end);
 
                         if (importedFile && resolution.isExternalLibraryImport) {
+                            // Since currently irrespective of allowJs, we only look for supportedTypeScript extension external module files,
+                            // this check is ok. Otherwise this would be never true for javascript file
                             if (!isExternalModule(importedFile)) {
                                 const start = getTokenPosOfNode(file.imports[i], file);
                                 fileProcessingDiagnostics.add(createFileDiagnostic(file, start, file.imports[i].end - start, Diagnostics.Exported_external_package_typings_file_0_is_not_a_module_Please_contact_the_package_author_to_update_the_package_definition, importedFile.fileName));

src/compiler/scanner.ts

@@ -425,6 +425,12 @@ namespace ts {
 
       /* @internal */
       export function skipTrivia(text: string, pos: number, stopAfterLineBreak?: boolean): number {
+          // Using ! with a greater than test is a fast way of testing the following conditions:
+          //  pos === undefined || pos === null || isNaN(pos) || pos < 0;
+          if (!(pos >= 0)) {
+              return pos;
+          }
+
           // Keep in sync with couldStartTrivia
           while (true) {
               const ch = text.charCodeAt(pos);
@@ -567,12 +573,12 @@ namespace ts {
     }
 
     /**
-     * Extract comments from text prefixing the token closest following `pos`. 
+     * Extract comments from text prefixing the token closest following `pos`.
      * The return value is an array containing a TextRange for each comment.
      * Single-line comment ranges include the beginning '//' characters but not the ending line break.
      * Multi - line comment ranges include the beginning '/* and ending '<asterisk>/' characters.
      * The return value is undefined if no comments were found.
-     * @param trailing 
+     * @param trailing
      * If false, whitespace is skipped until the first line break and comments between that location
      * and the next token are returned.
      * If true, comments occurring between the given position and the next line break are returned.

src/compiler/sourcemap.ts

@@ -0,0 +1,332 @@
+/// <reference path="checker.ts"/>
+
+/* @internal */
+namespace ts {
+    export interface SourceMapWriter {
+        getSourceMapData(): SourceMapData;
+        setSourceFile(sourceFile: SourceFile): void;
+        emitPos(pos: number): void;
+        emitStart(range: TextRange): void;
+        emitEnd(range: TextRange): void;
+        getText(): string;
+        getSourceMappingURL(): string;
+        initialize(filePath: string, sourceMapFilePath: string, sourceFiles: SourceFile[], isBundledEmit: boolean): void;
+        reset(): void;
+    }
+
+    const nop = <(...args: any[]) => any>Function.prototype;
+    let nullSourceMapWriter: SourceMapWriter;
+
+    export function getNullSourceMapWriter(): SourceMapWriter {
+        if (nullSourceMapWriter === undefined) {
+            nullSourceMapWriter = {
+                getSourceMapData(): SourceMapData { return undefined; },
+                setSourceFile(sourceFile: SourceFile): void { },
+                emitStart(range: TextRange): void { },
+                emitEnd(range: TextRange): void { },
+                emitPos(pos: number): void { },
+                getText(): string { return undefined; },
+                getSourceMappingURL(): string { return undefined; },
+                initialize(filePath: string, sourceMapFilePath: string, sourceFiles: SourceFile[], isBundledEmit: boolean): void { },
+                reset(): void { },
+            };
+        }
+
+        return nullSourceMapWriter;
+    }
+
+    export function createSourceMapWriter(host: EmitHost, writer: EmitTextWriter): SourceMapWriter {
+        const compilerOptions = host.getCompilerOptions();
+        let currentSourceFile: SourceFile;
+        let sourceMapDir: string; // The directory in which sourcemap will be
+
+        // Current source map file and its index in the sources list
+        let sourceMapSourceIndex: number;
+
+        // Last recorded and encoded spans
+        let lastRecordedSourceMapSpan: SourceMapSpan;
+        let lastEncodedSourceMapSpan: SourceMapSpan;
+        let lastEncodedNameIndex: number;
+
+        // Source map data
+        let sourceMapData: SourceMapData;
+
+        return {
+            getSourceMapData: () => sourceMapData,
+            setSourceFile,
+            emitPos,
+            emitStart,
+            emitEnd,
+            getText,
+            getSourceMappingURL,
+            initialize,
+            reset,
+        };
+
+        function initialize(filePath: string, sourceMapFilePath: string, sourceFiles: SourceFile[], isBundledEmit: boolean) {
+            if (sourceMapData) {
+                reset();
+            }
+
+            currentSourceFile = undefined;
+
+            // Current source map file and its index in the sources list
+            sourceMapSourceIndex = -1;
+
+            // Last recorded and encoded spans
+            lastRecordedSourceMapSpan = undefined;
+            lastEncodedSourceMapSpan = {
+                emittedLine: 1,
+                emittedColumn: 1,
+                sourceLine: 1,
+                sourceColumn: 1,
+                sourceIndex: 0
+            };
+            lastEncodedNameIndex = 0;
+
+            // Initialize source map data
+            sourceMapData = {
+                sourceMapFilePath: sourceMapFilePath,
+                jsSourceMappingURL: !compilerOptions.inlineSourceMap ? getBaseFileName(normalizeSlashes(sourceMapFilePath)) : undefined,
+                sourceMapFile: getBaseFileName(normalizeSlashes(filePath)),
+                sourceMapSourceRoot: compilerOptions.sourceRoot || "",
+                sourceMapSources: [],
+                inputSourceFileNames: [],
+                sourceMapNames: [],
+                sourceMapMappings: "",
+                sourceMapSourcesContent: compilerOptions.inlineSources ? [] : undefined,
+                sourceMapDecodedMappings: []
+            };
+
+            // Normalize source root and make sure it has trailing "/" so that it can be used to combine paths with the
+            // relative paths of the sources list in the sourcemap
+            sourceMapData.sourceMapSourceRoot = ts.normalizeSlashes(sourceMapData.sourceMapSourceRoot);
+            if (sourceMapData.sourceMapSourceRoot.length && sourceMapData.sourceMapSourceRoot.charCodeAt(sourceMapData.sourceMapSourceRoot.length - 1) !== CharacterCodes.slash) {
+                sourceMapData.sourceMapSourceRoot += directorySeparator;
+            }
+
+            if (compilerOptions.mapRoot) {
+                sourceMapDir = normalizeSlashes(compilerOptions.mapRoot);
+                if (!isBundledEmit) { // emitting single module file
+                    Debug.assert(sourceFiles.length === 1);
+                    // For modules or multiple emit files the mapRoot will have directory structure like the sources
+                    // So if src\a.ts and src\lib\b.ts are compiled together user would be moving the maps into mapRoot\a.js.map and mapRoot\lib\b.js.map
+                    sourceMapDir = getDirectoryPath(getSourceFilePathInNewDir(sourceFiles[0], host, sourceMapDir));
+                }
+
+                if (!isRootedDiskPath(sourceMapDir) && !isUrl(sourceMapDir)) {
+                    // The relative paths are relative to the common directory
+                    sourceMapDir = combinePaths(host.getCommonSourceDirectory(), sourceMapDir);
+                    sourceMapData.jsSourceMappingURL = getRelativePathToDirectoryOrUrl(
+                        getDirectoryPath(normalizePath(filePath)), // get the relative sourceMapDir path based on jsFilePath
+                        combinePaths(sourceMapDir, sourceMapData.jsSourceMappingURL), // this is where user expects to see sourceMap
+                        host.getCurrentDirectory(),
+                        host.getCanonicalFileName,
+                        /*isAbsolutePathAnUrl*/ true);
+                }
+                else {
+                    sourceMapData.jsSourceMappingURL = combinePaths(sourceMapDir, sourceMapData.jsSourceMappingURL);
+                }
+            }
+            else {
+                sourceMapDir = getDirectoryPath(normalizePath(filePath));
+            }
+        }
+
+        function reset() {
+            currentSourceFile = undefined;
+            sourceMapDir = undefined;
+            sourceMapSourceIndex = undefined;
+            lastRecordedSourceMapSpan = undefined;
+            lastEncodedSourceMapSpan = undefined;
+            lastEncodedNameIndex = undefined;
+            sourceMapData = undefined;
+        }
+
+        // Encoding for sourcemap span
+        function encodeLastRecordedSourceMapSpan() {
+            if (!lastRecordedSourceMapSpan || lastRecordedSourceMapSpan === lastEncodedSourceMapSpan) {
+                return;
+            }
+
+            let prevEncodedEmittedColumn = lastEncodedSourceMapSpan.emittedColumn;
+            // Line/Comma delimiters
+            if (lastEncodedSourceMapSpan.emittedLine === lastRecordedSourceMapSpan.emittedLine) {
+                // Emit comma to separate the entry
+                if (sourceMapData.sourceMapMappings) {
+                    sourceMapData.sourceMapMappings += ",";
+                }
+            }
+            else {
+                // Emit line delimiters
+                for (let encodedLine = lastEncodedSourceMapSpan.emittedLine; encodedLine < lastRecordedSourceMapSpan.emittedLine; encodedLine++) {
+                    sourceMapData.sourceMapMappings += ";";
+                }
+                prevEncodedEmittedColumn = 1;
+            }
+
+            // 1. Relative Column 0 based
+            sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.emittedColumn - prevEncodedEmittedColumn);
+
+            // 2. Relative sourceIndex
+            sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceIndex - lastEncodedSourceMapSpan.sourceIndex);
+
+            // 3. Relative sourceLine 0 based
+            sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceLine - lastEncodedSourceMapSpan.sourceLine);
+
+            // 4. Relative sourceColumn 0 based
+            sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceColumn - lastEncodedSourceMapSpan.sourceColumn);
+
+            // 5. Relative namePosition 0 based
+            if (lastRecordedSourceMapSpan.nameIndex >= 0) {
+                sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.nameIndex - lastEncodedNameIndex);
+                lastEncodedNameIndex = lastRecordedSourceMapSpan.nameIndex;
+            }
+
+            lastEncodedSourceMapSpan = lastRecordedSourceMapSpan;
+            sourceMapData.sourceMapDecodedMappings.push(lastEncodedSourceMapSpan);
+        }
+
+        function emitPos(pos: number) {
+            if (pos === -1) {
+                return;
+            }
+
+            const sourceLinePos = getLineAndCharacterOfPosition(currentSourceFile, pos);
+
+            // Convert the location to be one-based.
+            sourceLinePos.line++;
+            sourceLinePos.character++;
+
+            const emittedLine = writer.getLine();
+            const emittedColumn = writer.getColumn();
+
+            // If this location wasn't recorded or the location in source is going backwards, record the span
+            if (!lastRecordedSourceMapSpan ||
+                lastRecordedSourceMapSpan.emittedLine !== emittedLine ||
+                lastRecordedSourceMapSpan.emittedColumn !== emittedColumn ||
+                (lastRecordedSourceMapSpan.sourceIndex === sourceMapSourceIndex &&
+                    (lastRecordedSourceMapSpan.sourceLine > sourceLinePos.line ||
+                        (lastRecordedSourceMapSpan.sourceLine === sourceLinePos.line && lastRecordedSourceMapSpan.sourceColumn > sourceLinePos.character)))) {
+
+                // Encode the last recordedSpan before assigning new
+                encodeLastRecordedSourceMapSpan();
+
+                // New span
+                lastRecordedSourceMapSpan = {
+                    emittedLine: emittedLine,
+                    emittedColumn: emittedColumn,
+                    sourceLine: sourceLinePos.line,
+                    sourceColumn: sourceLinePos.character,
+                    sourceIndex: sourceMapSourceIndex
+                };
+            }
+            else {
+                // Take the new pos instead since there is no change in emittedLine and column since last location
+                lastRecordedSourceMapSpan.sourceLine = sourceLinePos.line;
+                lastRecordedSourceMapSpan.sourceColumn = sourceLinePos.character;
+                lastRecordedSourceMapSpan.sourceIndex = sourceMapSourceIndex;
+            }
+        }
+
+        function emitStart(range: TextRange) {
+            const rangeHasDecorators = !!(range as Node).decorators;
+            emitPos(range.pos !== -1 ? skipTrivia(currentSourceFile.text, rangeHasDecorators ? (range as Node).decorators.end : range.pos) : -1);
+        }
+
+        function emitEnd(range: TextRange) {
+            emitPos(range.end);
+        }
+
+        function setSourceFile(sourceFile: SourceFile) {
+            currentSourceFile = sourceFile;
+
+            // Add the file to tsFilePaths
+            // If sourceroot option: Use the relative path corresponding to the common directory path
+            // otherwise source locations relative to map file location
+            const sourcesDirectoryPath = compilerOptions.sourceRoot ? host.getCommonSourceDirectory() : sourceMapDir;
+
+            const source = getRelativePathToDirectoryOrUrl(sourcesDirectoryPath,
+                currentSourceFile.fileName,
+                host.getCurrentDirectory(),
+                host.getCanonicalFileName,
+                /*isAbsolutePathAnUrl*/ true);
+
+            sourceMapSourceIndex = indexOf(sourceMapData.sourceMapSources, source);
+            if (sourceMapSourceIndex === -1) {
+                sourceMapSourceIndex = sourceMapData.sourceMapSources.length;
+                sourceMapData.sourceMapSources.push(source);
+
+                // The one that can be used from program to get the actual source file
+                sourceMapData.inputSourceFileNames.push(sourceFile.fileName);
+
+                if (compilerOptions.inlineSources) {
+                    sourceMapData.sourceMapSourcesContent.push(sourceFile.text);
+                }
+            }
+        }
+
+        function getText() {
+            encodeLastRecordedSourceMapSpan();
+
+            return stringify({
+                version: 3,
+                file: sourceMapData.sourceMapFile,
+                sourceRoot: sourceMapData.sourceMapSourceRoot,
+                sources: sourceMapData.sourceMapSources,
+                names: sourceMapData.sourceMapNames,
+                mappings: sourceMapData.sourceMapMappings,
+                sourcesContent: sourceMapData.sourceMapSourcesContent,
+            });
+        }
+
+        function getSourceMappingURL() {
+            if (compilerOptions.inlineSourceMap) {
+                // Encode the sourceMap into the sourceMap url
+                const base64SourceMapText = convertToBase64(getText());
+                return sourceMapData.jsSourceMappingURL = `data:application/json;base64,${base64SourceMapText}`;
+            }
+            else {
+                return sourceMapData.jsSourceMappingURL;
+            }
+        }
+    }
+
+    const base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    function base64FormatEncode(inValue: number) {
+        if (inValue < 64) {
+            return base64Chars.charAt(inValue);
+        }
+
+        throw TypeError(inValue + ": not a 64 based value");
+    }
+
+    function base64VLQFormatEncode(inValue: number) {
+        // Add a new least significant bit that has the sign of the value.
+        // if negative number the least significant bit that gets added to the number has value 1
+        // else least significant bit value that gets added is 0
+        // eg. -1 changes to binary : 01 [1] => 3
+        //     +1 changes to binary : 01 [0] => 2
+        if (inValue < 0) {
+            inValue = ((-inValue) << 1) + 1;
+        }
+        else {
+            inValue = inValue << 1;
+        }
+
+        // Encode 5 bits at a time starting from least significant bits
+        let encodedStr = "";
+        do {
+            let currentDigit = inValue & 31; // 11111
+            inValue = inValue >> 5;
+            if (inValue > 0) {
+                // There are still more digits to decode, set the msb (6th bit)
+                currentDigit = currentDigit | 32;
+            }
+            encodedStr = encodedStr + base64FormatEncode(currentDigit);
+        } while (inValue > 0);
+
+        return encodedStr;
+    }
+}

src/compiler/sys.ts

@@ -47,6 +47,21 @@ namespace ts {
         constructor(o: any);
     }
 
+    declare var ChakraHost: {
+        args: string[];
+        currentDirectory: string;
+        executingFile: string;
+        echo(s: string): void;
+        quit(exitCode?: number): void;
+        fileExists(path: string): boolean;
+        directoryExists(path: string): boolean;
+        createDirectory(path: string): void;
+        resolvePath(path: string): string;
+        readFile(path: string): string;
+        writeFile(path: string, contents: string): void;
+        readDirectory(path: string, extension?: string, exclude?: string[]): string[];
+    };
+
     export var sys: System = (function () {
 
         function getWScriptSystem(): System {
@@ -194,6 +209,7 @@ namespace ts {
                 }
             };
         }
+
         function getNodeSystem(): System {
             const _fs = require("fs");
             const _path = require("path");
@@ -281,7 +297,7 @@ namespace ts {
             // REVIEW: for now this implementation uses polling.
             // The advantage of polling is that it works reliably
             // on all os and with network mounted files.
-            // For 90 referenced files, the average time to detect 
+            // For 90 referenced files, the average time to detect
             // changes is 2*msInterval (by default 5 seconds).
             // The overhead of this is .04 percent (1/2500) with
             // average pause of < 1 millisecond (and max
@@ -406,7 +422,7 @@ namespace ts {
                     };
                 },
                 watchDirectory: (path, callback, recursive) => {
-                    // Node 4.0 `fs.watch` function supports the "recursive" option on both OSX and Windows 
+                    // Node 4.0 `fs.watch` function supports the "recursive" option on both OSX and Windows
                     // (ref: https://github.com/nodejs/node/pull/2649 and https://github.com/Microsoft/TypeScript/issues/4643)
                     return _fs.watch(
                         path,
@@ -454,6 +470,37 @@ namespace ts {
                 }
             };
         }
+
+        function getChakraSystem(): System {
+
+            return {
+                newLine: "\r\n",
+                args: ChakraHost.args,
+                useCaseSensitiveFileNames: false,
+                write: ChakraHost.echo,
+                readFile(path: string, encoding?: string) {
+                    // encoding is automatically handled by the implementation in ChakraHost
+                    return ChakraHost.readFile(path);
+                },
+                writeFile(path: string, data: string, writeByteOrderMark?: boolean) {
+                    // If a BOM is required, emit one
+                    if (writeByteOrderMark) {
+                        data = "\uFEFF" + data;
+                    }
+
+                    ChakraHost.writeFile(path, data);
+                },
+                resolvePath: ChakraHost.resolvePath,
+                fileExists: ChakraHost.fileExists,
+                directoryExists: ChakraHost.directoryExists,
+                createDirectory: ChakraHost.createDirectory,
+                getExecutingFilePath: () => ChakraHost.executingFile,
+                getCurrentDirectory: () => ChakraHost.currentDirectory,
+                readDirectory: ChakraHost.readDirectory,
+                exit: ChakraHost.quit,
+            };
+        }
+
         if (typeof WScript !== "undefined" && typeof ActiveXObject === "function") {
             return getWScriptSystem();
         }
@@ -462,8 +509,13 @@ namespace ts {
             // process.browser check excludes webpack and browserify
             return getNodeSystem();
         }
+        else if (typeof ChakraHost !== "undefined") {
+            return getChakraSystem();
+        }
         else {
             return undefined; // Unsupported host
         }
     })();
 }
+
+

src/compiler/types.ts

@@ -439,12 +439,16 @@ namespace ts {
 
     export const enum JsxFlags {
         None = 0,
+        /** An element from a named property of the JSX.IntrinsicElements interface */
         IntrinsicNamedElement = 1 << 0,
+        /** An element inferred from the string index signature of the JSX.IntrinsicElements interface */
         IntrinsicIndexedElement = 1 << 1,
-        ClassElement = 1 << 2,
-        UnknownElement = 1 << 3,
+        /** An element backed by a class, class-like, or function value */
+        ValueElement = 1 << 2,
+        /** Element resolution failed */
+        UnknownElement = 1 << 4,
 
-        IntrinsicElement = IntrinsicNamedElement | IntrinsicIndexedElement
+        IntrinsicElement = IntrinsicNamedElement | IntrinsicIndexedElement,
     }
 
 
@@ -587,6 +591,7 @@ namespace ts {
         name: PropertyName;                 // Declared property name
         questionToken?: Node;               // Present on optional property
         type?: TypeNode;                    // Optional type annotation
+        initializer?: Expression;           // Optional initializer
     }
 
     // @kind(SyntaxKind.PropertyDeclaration)
@@ -1752,7 +1757,7 @@ namespace ts {
     export interface SymbolDisplayBuilder {
         buildTypeDisplay(type: Type, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildSymbolDisplay(symbol: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, meaning?: SymbolFlags, flags?: SymbolFormatFlags): void;
-        buildSignatureDisplay(signatures: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
+        buildSignatureDisplay(signatures: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, kind?: SignatureKind): void;
         buildParameterDisplay(parameter: Symbol, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildTypeParameterDisplay(tp: TypeParameter, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags): void;
         buildTypeParameterDisplayFromSymbol(symbol: Symbol, writer: SymbolWriter, enclosingDeclaraiton?: Node, flags?: TypeFormatFlags): void;

src/compiler/utilities.ts

@@ -906,23 +906,6 @@ namespace ts {
         return false;
     }
 
-    export function childIsDecorated(node: Node): boolean {
-        switch (node.kind) {
-            case SyntaxKind.ClassDeclaration:
-                return forEach((<ClassDeclaration>node).members, nodeOrChildIsDecorated);
-
-            case SyntaxKind.MethodDeclaration:
-            case SyntaxKind.SetAccessor:
-                return forEach((<FunctionLikeDeclaration>node).parameters, nodeIsDecorated);
-        }
-
-        return false;
-    }
-
-    export function nodeOrChildIsDecorated(node: Node): boolean {
-        return nodeIsDecorated(node) || childIsDecorated(node);
-    }
-
     export function isPropertyAccessExpression(node: Node): node is PropertyAccessExpression {
         return node.kind === SyntaxKind.PropertyAccessExpression;
     }
@@ -1906,8 +1889,10 @@ namespace ts {
      * Resolves a local path to a path which is absolute to the base of the emit
      */
     export function getExternalModuleNameFromPath(host: EmitHost, fileName: string): string {
-        const dir = toPath(host.getCommonSourceDirectory(), host.getCurrentDirectory(), f => host.getCanonicalFileName(f));
-        const relativePath = getRelativePathToDirectoryOrUrl(dir, fileName, dir, f => host.getCanonicalFileName(f), /*isAbsolutePathAnUrl*/ false);
+        const getCanonicalFileName = (f: string) => host.getCanonicalFileName(f);
+        const dir = toPath(host.getCommonSourceDirectory(), host.getCurrentDirectory(), getCanonicalFileName);
+        const filePath = getNormalizedAbsolutePath(fileName, host.getCurrentDirectory());
+        const relativePath = getRelativePathToDirectoryOrUrl(dir, filePath, dir, getCanonicalFileName, /*isAbsolutePathAnUrl*/ false);
         return removeFileExtension(relativePath);
     }
 
@@ -2411,6 +2396,55 @@ namespace ts {
         return output;
     }
 
+    /**
+     * Serialize an object graph into a JSON string. This is intended only for use on an acyclic graph
+     * as the fallback implementation does not check for circular references by default.
+     */
+    export const stringify: (value: any) => string = typeof JSON !== "undefined" && JSON.stringify
+        ? JSON.stringify
+        : stringifyFallback;
+
+    /**
+     * Serialize an object graph into a JSON string.
+     */
+    function stringifyFallback(value: any): string {
+        // JSON.stringify returns `undefined` here, instead of the string "undefined".
+        return value === undefined ? undefined : stringifyValue(value);
+    }
+
+    function stringifyValue(value: any): string {
+        return typeof value === "string" ? `"${escapeString(value)}"`
+             : typeof value === "number" ? isFinite(value) ? String(value) : "null"
+             : typeof value === "boolean" ? value ? "true" : "false"
+             : typeof value === "object" && value ? isArray(value) ? cycleCheck(stringifyArray, value) : cycleCheck(stringifyObject, value)
+             : /*fallback*/ "null";
+    }
+
+    function cycleCheck(cb: (value: any) => string, value: any) {
+        Debug.assert(!value.hasOwnProperty("__cycle"), "Converting circular structure to JSON");
+        value.__cycle = true;
+        const result = cb(value);
+        delete value.__cycle;
+        return result;
+    }
+
+    function stringifyArray(value: any) {
+        return `[${reduceLeft(value, stringifyElement, "")}]`;
+    }
+
+    function stringifyElement(memo: string, value: any) {
+        return (memo ? memo + "," : memo) + stringifyValue(value);
+    }
+
+    function stringifyObject(value: any) {
+        return `{${reduceProperties(value, stringifyProperty, "")}}`;
+    }
+
+    function stringifyProperty(memo: string, value: any, key: string) {
+        return value === undefined || typeof value === "function" || key === "__cycle" ? memo
+             : (memo ? memo + "," : memo) + `"${escapeString(key)}":${stringifyValue(value)}`;
+    }
+
     const base64Digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
 
     /**

src/harness/compilerRunner.ts

@@ -142,7 +142,7 @@ class CompilerBaselineRunner extends RunnerBase {
 
             it("Correct JS output for " + fileName, () => {
                 if (hasNonDtsFiles && this.emit) {
-                    if (result.files.length === 0 && result.errors.length === 0) {
+                    if (!options.noEmit && result.files.length === 0 && result.errors.length === 0) {
                         throw new Error("Expected at least one js file to be emitted or at least one error to be created.");
                     }
 

src/harness/harness.ts

@@ -908,6 +908,7 @@ namespace Harness {
             useCaseSensitiveFileNames?: boolean;
             includeBuiltFile?: string;
             baselineFile?: string;
+            libFiles?: string;
         }
 
         // Additional options not already in ts.optionDeclarations 
@@ -917,6 +918,7 @@ namespace Harness {
             { name: "baselineFile", type: "string" },
             { name: "includeBuiltFile", type: "string" },
             { name: "fileName", type: "string" },
+            { name: "libFiles", type: "string" },
             { name: "noErrorTruncation", type: "boolean" }
         ];
 
@@ -995,14 +997,11 @@ namespace Harness {
             currentDirectory = currentDirectory || Harness.IO.getCurrentDirectory();
 
             // Parse settings
-            let useCaseSensitiveFileNames = Harness.IO.useCaseSensitiveFileNames();
             if (harnessSettings) {
                 setCompilerOptionsFromHarnessSetting(harnessSettings, options);
             }
-            if (options.useCaseSensitiveFileNames !== undefined) {
-                useCaseSensitiveFileNames = options.useCaseSensitiveFileNames;
-            }
 
+            const useCaseSensitiveFileNames = options.useCaseSensitiveFileNames !== undefined ? options.useCaseSensitiveFileNames : Harness.IO.useCaseSensitiveFileNames();
             const programFiles: TestFile[] = inputFiles.slice();
             // Files from built\local that are requested by test "@includeBuiltFiles" to be in the context.
             // Treat them as library files, so include them in build, but not in baselines.
@@ -1017,6 +1016,15 @@ namespace Harness {
 
             const fileOutputs: GeneratedFile[] = [];
 
+            // Files from tests\lib that are requested by "@libFiles"
+            if (options.libFiles) {
+                for (const fileName of options.libFiles.split(",")) {
+                    const libFileName = "tests/lib/" + fileName;
+                    programFiles.push({ unitName: libFileName, content: normalizeLineEndings(IO.readFile(libFileName), Harness.IO.newLine()) });
+                }
+            }
+
+
             const programFileNames = programFiles.map(file => file.unitName);
 
             const compilerHost = createCompilerHost(

src/harness/sourceMapRecorder.ts

@@ -172,7 +172,6 @@ namespace Harness.SourceMapRecoder {
                     return { error: errorDecodeOfEncodedMapping, sourceMapSpan: decodeOfEncodedMapping };
                 }
                 // 5. Check if there is name:
-                decodeOfEncodedMapping.nameIndex = -1;
                 if (!isSourceMappingSegmentEnd()) {
                     prevNameIndex += base64VLQFormatDecode();
                     decodeOfEncodedMapping.nameIndex = prevNameIndex;
@@ -249,7 +248,7 @@ namespace Harness.SourceMapRecoder {
                 mapString += " name (" + sourceMapNames[mapEntry.nameIndex] + ")";
             }
             else {
-                if (mapEntry.nameIndex !== -1 || getAbsentNameIndex) {
+                if ((mapEntry.nameIndex && mapEntry.nameIndex !== -1) || getAbsentNameIndex) {
                     mapString += " nameIndex (" + mapEntry.nameIndex + ")";
                 }
             }

src/lib/dom.generated.d.ts

@@ -2058,6 +2058,7 @@ interface Document extends Node, GlobalEventHandlers, NodeSelector, DocumentEven
       * Gets or sets the version attribute specified in the declaration of an XML document.
       */
     xmlVersion: string;
+    currentScript: HTMLScriptElement;
     adoptNode(source: Node): Node;
     captureEvents(): void;
     clear(): void;
@@ -2977,6 +2978,7 @@ interface Element extends Node, GlobalEventHandlers, ElementTraversal, NodeSelec
     webkitRequestFullScreen(): void;
     webkitRequestFullscreen(): void;
     getElementsByClassName(classNames: string): NodeListOf<Element>;
+    matches(selector: string): boolean;
     addEventListener(type: "MSGestureChange", listener: (ev: MSGestureEvent) => any, useCapture?: boolean): void;
     addEventListener(type: "MSGestureDoubleTap", listener: (ev: MSGestureEvent) => any, useCapture?: boolean): void;
     addEventListener(type: "MSGestureEnd", listener: (ev: MSGestureEvent) => any, useCapture?: boolean): void;
@@ -3961,7 +3963,6 @@ interface HTMLElement extends Element {
     title: string;
     blur(): void;
     click(): void;
-    contains(child: HTMLElement): boolean;
     dragDrop(): boolean;
     focus(): void;
     insertAdjacentElement(position: string, insertedElement: Element): Element;
@@ -6135,7 +6136,7 @@ interface HTMLSelectElement extends HTMLElement {
       * Sets or retrieves the name of the object.
       */
     name: string;
-    options: HTMLSelectElement;
+    options: HTMLCollection;
     /**
       * When present, marks an element that can't be submitted without a value.
       */
@@ -6421,19 +6422,19 @@ interface HTMLTableElement extends HTMLElement {
     /**
       * Creates an empty caption element in the table.
       */
-    createCaption(): HTMLElement;
+    createCaption(): HTMLTableCaptionElement;
     /**
       * Creates an empty tBody element in the table.
       */
-    createTBody(): HTMLElement;
+    createTBody(): HTMLTableSectionElement;
     /**
       * Creates an empty tFoot element in the table.
       */
-    createTFoot(): HTMLElement;
+    createTFoot(): HTMLTableSectionElement;
     /**
       * Returns the tHead element object if successful, or null otherwise.
       */
-    createTHead(): HTMLElement;
+    createTHead(): HTMLTableSectionElement;
     /**
       * Deletes the caption element and its contents from the table.
       */
@@ -6455,7 +6456,7 @@ interface HTMLTableElement extends HTMLElement {
       * Creates a new row (tr) in the table, and adds the row to the rows collection.
       * @param index Number that specifies where to insert the row in the rows collection. The default value is -1, which appends the new row to the end of the rows collection.
       */
-    insertRow(index?: number): HTMLElement;
+    insertRow(index?: number): HTMLTableRowElement;
 }
 
 declare var HTMLTableElement: {
@@ -6506,7 +6507,7 @@ interface HTMLTableRowElement extends HTMLElement, HTMLTableAlignment {
       * Creates a new cell in the table row, and adds the cell to the cells collection.
       * @param index Number that specifies where to insert the cell in the tr. The default value is -1, which appends the new cell to the end of the cells collection.
       */
-    insertCell(index?: number): HTMLElement;
+    insertCell(index?: number): HTMLTableCellElement;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
 }
 
@@ -6533,7 +6534,7 @@ interface HTMLTableSectionElement extends HTMLElement, HTMLTableAlignment {
       * Creates a new row (tr) in the table, and adds the row to the rows collection.
       * @param index Number that specifies where to insert the row in the rows collection. The default value is -1, which appends the new row to the end of the rows collection.
       */
-    insertRow(index?: number): HTMLElement;
+    insertRow(index?: number): HTMLTableRowElement;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
 }
 
@@ -7071,7 +7072,7 @@ declare var IDBVersionChangeEvent: {
 }
 
 interface ImageData {
-    data: number[];
+    data: Uint8ClampedArray;
     height: number;
     width: number;
 }
@@ -7869,6 +7870,7 @@ interface Navigator extends Object, NavigatorID, NavigatorOnLine, NavigatorConte
     getGamepads(): Gamepad[];
     javaEnabled(): boolean;
     msLaunchUri(uri: string, successCallback?: MSLaunchUriCallback, noHandlerCallback?: MSLaunchUriCallback): void;
+    vibrate(pattern: number | number[]): boolean;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, useCapture?: boolean): void;
 }
 
@@ -7909,6 +7911,7 @@ interface Node extends EventTarget {
     normalize(): void;
     removeChild(oldChild: Node): Node;
     replaceChild(newChild: Node, oldChild: Node): Node;
+    contains(node: Node): boolean;
     ATTRIBUTE_NODE: number;
     CDATA_SECTION_NODE: number;
     COMMENT_NODE: number;

src/lib/webworker.generated.d.ts

@@ -460,7 +460,7 @@ declare var IDBVersionChangeEvent: {
 }
 
 interface ImageData {
-    data: number[];
+    data: Uint8ClampedArray;
     height: number;
     width: number;
 }

src/services/breakpoints.ts

@@ -16,7 +16,7 @@ namespace ts.BreakpointResolver {
 
         let tokenAtLocation = getTokenAtPosition(sourceFile, position);
         let lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
-        if (sourceFile.getLineAndCharacterOfPosition(tokenAtLocation.getStart()).line > lineOfPosition) {
+        if (sourceFile.getLineAndCharacterOfPosition(tokenAtLocation.getStart(sourceFile)).line > lineOfPosition) {
             // Get previous token if the token is returned starts on new line
             // eg: let x =10; |--- cursor is here
             //     let y = 10; 
@@ -39,16 +39,23 @@ namespace ts.BreakpointResolver {
         return spanInNode(tokenAtLocation);
 
         function textSpan(startNode: Node, endNode?: Node) {
-            return createTextSpanFromBounds(startNode.getStart(), (endNode || startNode).getEnd());
+            const start = startNode.decorators ?
+                skipTrivia(sourceFile.text, startNode.decorators.end) :
+                startNode.getStart(sourceFile);
+            return createTextSpanFromBounds(start, (endNode || startNode).getEnd());
         }
 
         function spanInNodeIfStartsOnSameLine(node: Node, otherwiseOnNode?: Node): TextSpan {
-            if (node && lineOfPosition === sourceFile.getLineAndCharacterOfPosition(node.getStart()).line) {
+            if (node && lineOfPosition === sourceFile.getLineAndCharacterOfPosition(node.getStart(sourceFile)).line) {
                 return spanInNode(node);
             }
             return spanInNode(otherwiseOnNode);
         }
 
+        function spanInNodeArray<T>(nodeArray: NodeArray<T>) {
+            return createTextSpanFromBounds(skipTrivia(sourceFile.text, nodeArray.pos), nodeArray.end);
+        }
+
         function spanInPreviousNode(node: Node): TextSpan {
             return spanInNode(findPrecedingToken(node.pos, sourceFile));
         }
@@ -65,6 +72,11 @@ namespace ts.BreakpointResolver {
                         return spanInPreviousNode(node);
                     }
 
+                    if (node.parent.kind === SyntaxKind.Decorator) {
+                        // Set breakpoint on the decorator emit
+                        return spanInNode(node.parent);
+                    }
+
                     if (node.parent.kind === SyntaxKind.ForStatement) {
                         // For now lets set the span on this expression, fix it later
                         return textSpan(node);
@@ -207,6 +219,9 @@ namespace ts.BreakpointResolver {
                         // span in statement
                         return spanInNode((<WithStatement>node).statement);
 
+                    case SyntaxKind.Decorator:
+                        return spanInNodeArray(node.parent.decorators);
+
                     // No breakpoint in interface, type alias
                     case SyntaxKind.InterfaceDeclaration:
                     case SyntaxKind.TypeAliasDeclaration:

src/services/services.ts

@@ -1901,7 +1901,7 @@ namespace ts {
                     sourceMapText = text;
                 }
                 else {
-                    Debug.assert(outputText === undefined, "Unexpected multiple outputs for the file: " + name);
+                    Debug.assert(outputText === undefined, `Unexpected multiple outputs for the file: '${name}'`);
                     outputText = text;
                 }
             },
@@ -4248,28 +4248,31 @@ namespace ts {
                 }
                 else {
                     // Method/function type parameter
-                    let container = getContainingFunction(location);
-                    if (container) {
-                        let signatureDeclaration = <SignatureDeclaration>getDeclarationOfKind(symbol, SyntaxKind.TypeParameter).parent;
-                        let signature = typeChecker.getSignatureFromDeclaration(signatureDeclaration);
-                        if (signatureDeclaration.kind === SyntaxKind.ConstructSignature) {
-                            displayParts.push(keywordPart(SyntaxKind.NewKeyword));
+                    let declaration = <Node>getDeclarationOfKind(symbol, SyntaxKind.TypeParameter);
+                    Debug.assert(declaration !== undefined);
+                    declaration = declaration.parent;
+
+                    if (declaration) {
+                        if (isFunctionLikeKind(declaration.kind)) {
+                            const signature = typeChecker.getSignatureFromDeclaration(<SignatureDeclaration>declaration);
+                            if (declaration.kind === SyntaxKind.ConstructSignature) {
+                                displayParts.push(keywordPart(SyntaxKind.NewKeyword));
+                                displayParts.push(spacePart());
+                            }
+                            else if (declaration.kind !== SyntaxKind.CallSignature && (<SignatureDeclaration>declaration).name) {
+                                addFullSymbolName(declaration.symbol);
+                            }
+                            addRange(displayParts, signatureToDisplayParts(typeChecker, signature, sourceFile, TypeFormatFlags.WriteTypeArgumentsOfSignature));
+                        }
+                        else {
+                            // Type alias type parameter
+                            // For example
+                            //      type list<T> = T[];  // Both T will go through same code path
+                            displayParts.push(keywordPart(SyntaxKind.TypeKeyword));
                             displayParts.push(spacePart());
+                            addFullSymbolName(declaration.symbol);
+                            writeTypeParametersOfSymbol(declaration.symbol, sourceFile);
                         }
-                        else if (signatureDeclaration.kind !== SyntaxKind.CallSignature && signatureDeclaration.name) {
-                            addFullSymbolName(signatureDeclaration.symbol);
-                        }
-                        addRange(displayParts, signatureToDisplayParts(typeChecker, signature, sourceFile, TypeFormatFlags.WriteTypeArgumentsOfSignature));
-                    }
-                    else {
-                        // Type  aliash type parameter
-                        // For example
-                        //      type list<T> = T[];  // Both T will go through same code path
-                        let declaration = <TypeAliasDeclaration>getDeclarationOfKind(symbol, SyntaxKind.TypeParameter).parent;
-                        displayParts.push(keywordPart(SyntaxKind.TypeKeyword));
-                        displayParts.push(spacePart());
-                        addFullSymbolName(declaration.symbol);
-                        writeTypeParametersOfSymbol(declaration.symbol, sourceFile);
                     }
                 }
             }