Merge master to release-2.0 on 08/19

src/compiler/checker.ts

@@ -1024,7 +1024,7 @@ namespace ts {
         }
 
         function getDeclarationOfAliasSymbol(symbol: Symbol): Declaration {
-            return find(symbol.declarations, d => isAliasSymbolDeclaration(d) ? d : undefined);
+            return findMap(symbol.declarations, d => isAliasSymbolDeclaration(d) ? d : undefined);
         }
 
         function getTargetOfImportEqualsDeclaration(node: ImportEqualsDeclaration): Symbol {
@@ -1361,7 +1361,14 @@ namespace ts {
 
             if (moduleNotFoundError) {
                 // report errors only if it was requested
-                error(moduleReferenceLiteral, moduleNotFoundError, moduleName);
+                const tsExtension = tryExtractTypeScriptExtension(moduleName);
+                if (tsExtension) {
+                    const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
+                    error(moduleReferenceLiteral, diag, tsExtension, removeExtension(moduleName, tsExtension));
+                }
+                else {
+                    error(moduleReferenceLiteral, moduleNotFoundError, moduleName);
+                }
             }
             return undefined;
         }
@@ -3083,7 +3090,7 @@ namespace ts {
 
             // If the declaration specifies a binding pattern, use the type implied by the binding pattern
             if (isBindingPattern(declaration.name)) {
-                return getTypeFromBindingPattern(<BindingPattern>declaration.name, /*includePatternInType*/ false);
+                return getTypeFromBindingPattern(<BindingPattern>declaration.name, /*includePatternInType*/ false, /*reportErrors*/ true);
             }
 
             // No type specified and nothing can be inferred
@@ -3093,23 +3100,21 @@ namespace ts {
         // Return the type implied by a binding pattern element. This is the type of the initializer of the element if
         // one is present. Otherwise, if the element is itself a binding pattern, it is the type implied by the binding
         // pattern. Otherwise, it is the type any.
-        function getTypeFromBindingElement(element: BindingElement, includePatternInType?: boolean): Type {
+        function getTypeFromBindingElement(element: BindingElement, includePatternInType?: boolean, reportErrors?: boolean): Type {
             if (element.initializer) {
-                const type = checkExpressionCached(element.initializer);
-                reportErrorsFromWidening(element, type);
-                return getWidenedType(type);
+                return checkExpressionCached(element.initializer);
             }
             if (isBindingPattern(element.name)) {
-                return getTypeFromBindingPattern(<BindingPattern>element.name, includePatternInType);
+                return getTypeFromBindingPattern(<BindingPattern>element.name, includePatternInType, reportErrors);
             }
-            if (compilerOptions.noImplicitAny && !declarationBelongsToPrivateAmbientMember(element)) {
+            if (reportErrors && compilerOptions.noImplicitAny && !declarationBelongsToPrivateAmbientMember(element)) {
                 reportImplicitAnyError(element, anyType);
             }
             return anyType;
         }
 
         // Return the type implied by an object binding pattern
-        function getTypeFromObjectBindingPattern(pattern: BindingPattern, includePatternInType: boolean): Type {
+        function getTypeFromObjectBindingPattern(pattern: BindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
             const members = createMap<Symbol>();
             let hasComputedProperties = false;
             forEach(pattern.elements, e => {
@@ -3123,7 +3128,7 @@ namespace ts {
                 const text = getTextOfPropertyName(name);
                 const flags = SymbolFlags.Property | SymbolFlags.Transient | (e.initializer ? SymbolFlags.Optional : 0);
                 const symbol = <TransientSymbol>createSymbol(flags, text);
-                symbol.type = getTypeFromBindingElement(e, includePatternInType);
+                symbol.type = getTypeFromBindingElement(e, includePatternInType, reportErrors);
                 symbol.bindingElement = e;
                 members[symbol.name] = symbol;
             });
@@ -3138,13 +3143,13 @@ namespace ts {
         }
 
         // Return the type implied by an array binding pattern
-        function getTypeFromArrayBindingPattern(pattern: BindingPattern, includePatternInType: boolean): Type {
+        function getTypeFromArrayBindingPattern(pattern: BindingPattern, includePatternInType: boolean, reportErrors: boolean): Type {
             const elements = pattern.elements;
             if (elements.length === 0 || elements[elements.length - 1].dotDotDotToken) {
                 return languageVersion >= ScriptTarget.ES6 ? createIterableType(anyType) : anyArrayType;
             }
             // If the pattern has at least one element, and no rest element, then it should imply a tuple type.
-            const elementTypes = map(elements, e => e.kind === SyntaxKind.OmittedExpression ? anyType : getTypeFromBindingElement(e, includePatternInType));
+            const elementTypes = map(elements, e => e.kind === SyntaxKind.OmittedExpression ? anyType : getTypeFromBindingElement(e, includePatternInType, reportErrors));
             if (includePatternInType) {
                 const result = createNewTupleType(elementTypes);
                 result.pattern = pattern;
@@ -3160,10 +3165,10 @@ namespace ts {
         // used as the contextual type of an initializer associated with the binding pattern. Also, for a destructuring
         // parameter with no type annotation or initializer, the type implied by the binding pattern becomes the type of
         // the parameter.
-        function getTypeFromBindingPattern(pattern: BindingPattern, includePatternInType?: boolean): Type {
+        function getTypeFromBindingPattern(pattern: BindingPattern, includePatternInType?: boolean, reportErrors?: boolean): Type {
             return pattern.kind === SyntaxKind.ObjectBindingPattern
-                ? getTypeFromObjectBindingPattern(pattern, includePatternInType)
-                : getTypeFromArrayBindingPattern(pattern, includePatternInType);
+                ? getTypeFromObjectBindingPattern(pattern, includePatternInType, reportErrors)
+                : getTypeFromArrayBindingPattern(pattern, includePatternInType, reportErrors);
         }
 
         // Return the type associated with a variable, parameter, or property declaration. In the simple case this is the type
@@ -9414,7 +9419,7 @@ namespace ts {
                     }
                 }
                 if (isBindingPattern(declaration.name)) {
-                    return getTypeFromBindingPattern(<BindingPattern>declaration.name, /*includePatternInType*/ true);
+                    return getTypeFromBindingPattern(<BindingPattern>declaration.name, /*includePatternInType*/ true, /*reportErrors*/ false);
                 }
                 if (isBindingPattern(declaration.parent)) {
                     const parentDeclaration = declaration.parent.parent;
@@ -14121,12 +14126,7 @@ namespace ts {
                 checkSignatureDeclaration(node);
                 if (node.kind === SyntaxKind.GetAccessor) {
                     if (!isInAmbientContext(node) && nodeIsPresent(node.body) && (node.flags & NodeFlags.HasImplicitReturn)) {
-                        if (node.flags & NodeFlags.HasExplicitReturn) {
-                            if (compilerOptions.noImplicitReturns) {
-                                error(node.name, Diagnostics.Not_all_code_paths_return_a_value);
-                            }
-                        }
-                        else {
+                        if (!(node.flags & NodeFlags.HasExplicitReturn)) {
                             error(node.name, Diagnostics.A_get_accessor_must_return_a_value);
                         }
                     }
@@ -14156,7 +14156,10 @@ namespace ts {
                         checkAccessorDeclarationTypesIdentical(node, otherAccessor, getThisTypeOfDeclaration, Diagnostics.get_and_set_accessor_must_have_the_same_this_type);
                     }
                 }
-                getTypeOfAccessors(getSymbolOfNode(node));
+                const returnType = getTypeOfAccessors(getSymbolOfNode(node));
+                if (node.kind === SyntaxKind.GetAccessor) {
+                    checkAllCodePathsInNonVoidFunctionReturnOrThrow(node, returnType);
+                }
             }
             if (node.parent.kind !== SyntaxKind.ObjectLiteralExpression) {
                 checkSourceElement(node.body);

src/compiler/core.ts

@@ -113,8 +113,22 @@ namespace ts {
         return undefined;
     }
 
-    /** Like `forEach`, but assumes existence of array and fails if no truthy value is found. */
-    export function find<T, U>(array: T[], callback: (element: T, index: number) => U | undefined): U {
+    /** Works like Array.prototype.find, returning `undefined` if no element satisfying the predicate is found. */
+    export function find<T>(array: T[], predicate: (element: T, index: number) => boolean): T | undefined {
+        for (let i = 0, len = array.length; i < len; i++) {
+            const value = array[i];
+            if (predicate(value, i)) {
+                return value;
+            }
+        }
+        return undefined;
+    }
+
+    /**
+     * Returns the first truthy result of `callback`, or else fails.
+     * This is like `forEach`, but never returns undefined.
+     */
+    export function findMap<T, U>(array: T[], callback: (element: T, index: number) => U | undefined): U {
         for (let i = 0, len = array.length; i < len; i++) {
             const result = callback(array[i], i);
             if (result) {
@@ -1315,6 +1329,8 @@ namespace ts {
      *  List of supported extensions in order of file resolution precedence.
      */
     export const supportedTypeScriptExtensions = [".ts", ".tsx", ".d.ts"];
+    /** Must have ".d.ts" first because if ".ts" goes first, that will be detected as the extension instead of ".d.ts". */
+    export const supportedTypescriptExtensionsForExtractExtension = [".d.ts", ".ts", ".tsx"];
     export const supportedJavascriptExtensions = [".js", ".jsx"];
     const allSupportedExtensions  = supportedTypeScriptExtensions.concat(supportedJavascriptExtensions);
 
@@ -1397,8 +1413,12 @@ namespace ts {
         return path;
     }
 
-    export function tryRemoveExtension(path: string, extension: string): string {
-        return fileExtensionIs(path, extension) ? path.substring(0, path.length - extension.length) : undefined;
+    export function tryRemoveExtension(path: string, extension: string): string | undefined {
+        return fileExtensionIs(path, extension) ? removeExtension(path, extension) : undefined;
+    }
+
+    export function removeExtension(path: string, extension: string): string {
+        return path.substring(0, path.length - extension.length);
     }
 
     export function isJsxOrTsxExtension(ext: string): boolean {

src/compiler/diagnosticMessages.json

@@ -1951,6 +1951,10 @@
         "category": "Error",
         "code": 2690
     },
+    "An import path cannot end with a '{0}' extension. Consider importing '{1}' instead.": {
+        "category": "Error",
+        "code": 2691
+    },
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000

src/compiler/parser.ts

@@ -3417,6 +3417,7 @@ namespace ts {
          *      6) - UnaryExpression[?yield]
          *      7) ~ UnaryExpression[?yield]
          *      8) ! UnaryExpression[?yield]
+         *      9) [+Await] await UnaryExpression[?yield]
          */
         function parseSimpleUnaryExpression(): UnaryExpression {
             switch (token()) {
@@ -3431,6 +3432,8 @@ namespace ts {
                     return parseTypeOfExpression();
                 case SyntaxKind.VoidKeyword:
                     return parseVoidExpression();
+                case SyntaxKind.AwaitKeyword:
+                    return parseAwaitExpression();
                 case SyntaxKind.LessThanToken:
                     // This is modified UnaryExpression grammar in TypeScript
                     //  UnaryExpression (modified):

src/compiler/program.ts

@@ -662,51 +662,52 @@ namespace ts {
      * @param {boolean} onlyRecordFailures - if true then function won't try to actually load files but instead record all attempts as failures. This flag is necessary
      * in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
      */
-    function loadModuleFromFile(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string {
-        // First try to keep/add an extension: importing "./foo.ts" can be matched by a file "./foo.ts", and "./foo" by "./foo.d.ts"
-        const resolvedByAddingOrKeepingExtension = loadModuleFromFileWorker(candidate, extensions, failedLookupLocation, onlyRecordFailures, state);
-        if (resolvedByAddingOrKeepingExtension) {
-            return resolvedByAddingOrKeepingExtension;
+    function loadModuleFromFile(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
+        // First, try adding an extension. An import of "foo" could be matched by a file "foo.ts", or "foo.js" by "foo.js.ts"
+        const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocation, onlyRecordFailures, state);
+        if (resolvedByAddingExtension) {
+            return resolvedByAddingExtension;
         }
-        // Then try stripping a ".js" or ".jsx" extension and replacing it with a TypeScript one, e.g. "./foo.js" can be matched by "./foo.ts" or "./foo.d.ts"
+
+        // If that didn't work, try stripping a ".js" or ".jsx" extension and replacing it with a TypeScript one;
+        // e.g. "./foo.js" can be matched by "./foo.ts" or "./foo.d.ts"
         if (hasJavaScriptFileExtension(candidate)) {
             const extensionless = removeFileExtension(candidate);
             if (state.traceEnabled) {
                 const extension = candidate.substring(extensionless.length);
                 trace(state.host, Diagnostics.File_name_0_has_a_1_extension_stripping_it, candidate, extension);
             }
-            return loadModuleFromFileWorker(extensionless, extensions, failedLookupLocation, onlyRecordFailures, state);
+            return tryAddingExtensions(extensionless, extensions, failedLookupLocation, onlyRecordFailures, state);
         }
     }
 
-    function loadModuleFromFileWorker(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string {
+    /** Try to return an existing file that adds one of the `extensions` to `candidate`. */
+    function tryAddingExtensions(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
         if (!onlyRecordFailures) {
             // check if containing folder exists - if it doesn't then just record failures for all supported extensions without disk probing
             const directory = getDirectoryPath(candidate);
             if (directory) {
                 onlyRecordFailures = !directoryProbablyExists(directory, state.host);
             }
         }
-        return forEach(extensions, tryLoad);
+        return forEach(extensions, ext =>
+            !(state.skipTsx && isJsxOrTsxExtension(ext)) && tryFile(candidate + ext, failedLookupLocation, onlyRecordFailures, state));
+    }
 
-        function tryLoad(ext: string): string {
-            if (state.skipTsx && isJsxOrTsxExtension(ext)) {
-                return undefined;
-            }
-            const fileName = fileExtensionIs(candidate, ext) ? candidate : candidate + ext;
-            if (!onlyRecordFailures && state.host.fileExists(fileName)) {
-                if (state.traceEnabled) {
-                    trace(state.host, Diagnostics.File_0_exist_use_it_as_a_name_resolution_result, fileName);
-                }
-                return fileName;
+    /** Return the file if it exists. */
+    function tryFile(fileName: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
+        if (!onlyRecordFailures && state.host.fileExists(fileName)) {
+            if (state.traceEnabled) {
+                trace(state.host, Diagnostics.File_0_exist_use_it_as_a_name_resolution_result, fileName);
             }
-            else {
-                if (state.traceEnabled) {
-                    trace(state.host, Diagnostics.File_0_does_not_exist, fileName);
-                }
-                failedLookupLocation.push(fileName);
-                return undefined;
+            return fileName;
+        }
+        else {
+            if (state.traceEnabled) {
+                trace(state.host, Diagnostics.File_0_does_not_exist, fileName);
             }
+            failedLookupLocation.push(fileName);
+            return undefined;
         }
     }
 
@@ -719,7 +720,9 @@ namespace ts {
             }
             const typesFile = tryReadTypesSection(packageJsonPath, candidate, state);
             if (typesFile) {
-                const result = loadModuleFromFile(typesFile, extensions, failedLookupLocation, !directoryProbablyExists(getDirectoryPath(typesFile), state.host), state);
+                const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
+                // The package.json "typings" property must specify the file with extension, so just try that exact filename.
+                const result = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state);
                 if (result) {
                     return result;
                 }

src/compiler/utilities.ts

@@ -2694,6 +2694,11 @@ namespace ts {
         return forEach(supportedTypeScriptExtensions, extension => fileExtensionIs(fileName, extension));
     }
 
+    /** Return ".ts", ".d.ts", or ".tsx", if that is the extension. */
+    export function tryExtractTypeScriptExtension(fileName: string): string | undefined {
+        return find(supportedTypescriptExtensionsForExtractExtension, extension => fileExtensionIs(fileName, extension));
+    }
+
     /**
      * Replace each instance of non-ascii characters by one, two, three, or four escape sequences
      * representing the UTF-8 encoding of the character, and return the expanded char code list.