Merge branch 'master' into builderApi

Author: sheetalkamat

.npmignore

@@ -18,4 +18,5 @@ Jakefile.js
 .settings/
 .travis.yml
 .vscode/
-test.config
+test.config
+package-lock.json

issue_template.md

@@ -1,10 +1,34 @@
-<!-- BUGS: Please use this template. -->
-<!-- QUESTIONS: This is not a general support forum! Ask Qs at http://stackoverflow.com/questions/tagged/typescript -->
-<!-- SUGGESTIONS: See https://github.com/Microsoft/TypeScript-wiki/blob/master/Writing-Good-Design-Proposals.md -->
+<!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨 -->
+<!--
+Half of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker.
+
+Please help us by doing the following steps before logging an issue:
+  * Search: https://github.com/Microsoft/TypeScript/search?type=Issues
+  * Read the CONTRIBUTING guidelines: https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md
+  * Read the FAQ: https://github.com/Microsoft/TypeScript/wiki/FAQ
+-->
+
+<!-- If you have a QUESTION:
+   THIS IS NOT A FORUM FOR QUESTIONS.
+   Ask questions at http://stackoverflow.com/questions/tagged/typescript
+    or https://gitter.im/Microsoft/TypeScript
+-->
+
+<!-- If you have a SUGGESTION:
+  Most suggestion reports are duplicates, please search extra hard before logging a new suggestion.
+  See https://github.com/Microsoft/TypeScript-wiki/blob/master/Writing-Good-Design-Proposals.md
+-->
+
+<!-- If you have a BUG:
+  Please fill in the *entire* template below.
+-->
 
 <!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. -->
 **TypeScript Version:**  2.7.0-dev.201xxxxx
 
+<!-- Search terms you tried before logging this (so others can find this issue more easily) -->
+**Search Terms:** 
+
 **Code**
 
 ```ts
@@ -16,4 +40,6 @@
 
 **Actual behavior:**
 
-**Related:**
+**Playground Link:** <!-- A link to a TypeScript Playground "Share" link which demonstrates this behavior --> 
+
+**Related Issues:**

src/compiler/checker.ts

@@ -6564,7 +6564,7 @@ namespace ts {
             // b) It references `arguments` somewhere
             const lastParam = lastOrUndefined(declaration.parameters);
             const lastParamTags = lastParam && getJSDocParameterTags(lastParam);
-            const lastParamVariadicType = lastParamTags && firstDefined(lastParamTags, p =>
+            const lastParamVariadicType = firstDefined(lastParamTags, p =>
                 p.typeExpression && isJSDocVariadicType(p.typeExpression.type) ? p.typeExpression.type : undefined);
             if (!lastParamVariadicType && !containsArgumentsReference(declaration)) {
                 return false;
@@ -9639,7 +9639,7 @@ namespace ts {
                 }
                 else if (target.flags & TypeFlags.IndexedAccess) {
                     // A type S is related to a type T[K] if S is related to A[K], where K is string-like and
-                    // A is the apparent type of T.
+                    // A is the constraint of T.
                     const constraint = getConstraintOfIndexedAccess(<IndexedAccessType>target);
                     if (constraint) {
                         if (result = isRelatedTo(source, constraint, reportErrors)) {
@@ -9675,18 +9675,19 @@ namespace ts {
                 }
                 else if (source.flags & TypeFlags.IndexedAccess) {
                     // A type S[K] is related to a type T if A[K] is related to T, where K is string-like and
-                    // A is the apparent type of S.
+                    // A is the constraint of S.
                     const constraint = getConstraintOfIndexedAccess(<IndexedAccessType>source);
                     if (constraint) {
                         if (result = isRelatedTo(constraint, target, reportErrors)) {
                             errorInfo = saveErrorInfo;
                             return result;
                         }
                     }
-                    else if (target.flags & TypeFlags.IndexedAccess && (<IndexedAccessType>source).indexType === (<IndexedAccessType>target).indexType) {
-                        // if we have indexed access types with identical index types, see if relationship holds for
-                        // the two object types.
+                    else if (target.flags & TypeFlags.IndexedAccess) {
                         if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
+                            result &= isRelatedTo((<IndexedAccessType>source).indexType, (<IndexedAccessType>target).indexType, reportErrors);
+                        }
+                        if (result) {
                             errorInfo = saveErrorInfo;
                             return result;
                         }
@@ -10967,7 +10968,7 @@ namespace ts {
             return type === typeParameter || type.flags & TypeFlags.UnionOrIntersection && forEach((<UnionOrIntersectionType>type).types, t => isTypeParameterAtTopLevel(t, typeParameter));
         }
 
-        /** Create an object with properties named in the string literal type. Every property has type `{}` */
+        /** Create an object with properties named in the string literal type. Every property has type `any` */
         function createEmptyObjectTypeFromStringLiteral(type: Type) {
             const members = createSymbolTable();
             forEachType(type, t => {
@@ -10976,7 +10977,7 @@ namespace ts {
                 }
                 const name = escapeLeadingUnderscores((t as StringLiteralType).value);
                 const literalProp = createSymbol(SymbolFlags.Property, name);
-                literalProp.type = emptyObjectType;
+                literalProp.type = anyType;
                 if (t.symbol) {
                     literalProp.declarations = t.symbol.declarations;
                     literalProp.valueDeclaration = t.symbol.valueDeclaration;
@@ -11031,7 +11032,9 @@ namespace ts {
             const templateType = getTemplateTypeFromMappedType(target);
             const inference = createInferenceInfo(typeParameter);
             inferTypes([inference], sourceType, templateType);
-            return inference.candidates ? getUnionType(inference.candidates, UnionReduction.Subtype) : emptyObjectType;
+            return inference.candidates ? getUnionType(inference.candidates, UnionReduction.Subtype) :
+                inference.contraCandidates ? getCommonSubtype(inference.contraCandidates) :
+                emptyObjectType;
         }
 
         function getUnmatchedProperty(source: Type, target: Type, requireOptionalProperties: boolean) {
@@ -18377,6 +18380,9 @@ namespace ts {
 
         function checkObjectLiteralAssignment(node: ObjectLiteralExpression, sourceType: Type): Type {
             const properties = node.properties;
+            if (strictNullChecks && properties.length === 0) {
+                return checkNonNullType(sourceType, node);
+            }
             for (const p of properties) {
                 checkObjectLiteralDestructuringPropertyAssignment(sourceType, p, properties);
             }
@@ -21446,7 +21452,13 @@ namespace ts {
             if (isBindingPattern(node.name)) {
                 // Don't validate for-in initializer as it is already an error
                 if (node.initializer && node.parent.parent.kind !== SyntaxKind.ForInStatement) {
-                    checkTypeAssignableTo(checkExpressionCached(node.initializer), getWidenedTypeForVariableLikeDeclaration(node), node, /*headMessage*/ undefined);
+                    const initializerType = checkExpressionCached(node.initializer);
+                    if (strictNullChecks && node.name.elements.length === 0) {
+                        checkNonNullType(initializerType, node);
+                    }
+                    else {
+                        checkTypeAssignableTo(initializerType, getWidenedTypeForVariableLikeDeclaration(node), node, /*headMessage*/ undefined);
+                    }
                     checkParameterInitializer(node);
                 }
                 return;
@@ -26196,14 +26208,18 @@ namespace ts {
         function checkGrammarBindingElement(node: BindingElement) {
             if (node.dotDotDotToken) {
                 const elements = (<BindingPattern>node.parent).elements;
-                if (node !== lastOrUndefined(elements)) {
+                if (node !== last(elements)) {
                     return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                 }
 
                 if (node.name.kind === SyntaxKind.ArrayBindingPattern || node.name.kind === SyntaxKind.ObjectBindingPattern) {
                     return grammarErrorOnNode(node.name, Diagnostics.A_rest_element_cannot_contain_a_binding_pattern);
                 }
 
+                if (node.propertyName) {
+                    return grammarErrorOnNode(node.name, Diagnostics.A_rest_element_cannot_have_a_property_name);
+                }
+
                 if (node.initializer) {
                     // Error on equals token which immediately precedes the initializer
                     return grammarErrorAtPos(node, node.initializer.pos - 1, 1, Diagnostics.A_rest_element_cannot_have_an_initializer);

src/compiler/core.ts

@@ -183,6 +183,10 @@ namespace ts {
 
     /** Like `forEach`, but suitable for use with numbers and strings (which may be falsy). */
     export function firstDefined<T, U>(array: ReadonlyArray<T> | undefined, callback: (element: T, index: number) => U | undefined): U | undefined {
+        if (array === undefined) {
+            return undefined;
+        }
+
         for (let i = 0; i < array.length; i++) {
             const result = callback(array[i], i);
             if (result !== undefined) {

src/compiler/diagnosticMessages.json

@@ -1976,6 +1976,10 @@
         "category": "Error",
         "code": 2565
     },
+    "A rest element cannot have a property name.": {
+        "category": "Error",
+        "code": 2566
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600
@@ -3893,10 +3897,6 @@
         "category": "Message",
         "code": 95002
     },
-    "Extract symbol": {
-        "category": "Message",
-        "code": 95003
-    },
     "Extract to {0} in {1}": {
         "category": "Message",
         "code": 95004

src/compiler/emitter.ts

@@ -1268,12 +1268,12 @@ namespace ts {
         }
 
         function emitBindingElement(node: BindingElement) {
+            emitIfPresent(node.dotDotDotToken);
             if (node.propertyName) {
                 emit(node.propertyName);
                 writePunctuation(":");
                 writeSpace();
             }
-            emitIfPresent(node.dotDotDotToken);
             emit(node.name);
             emitInitializer(node.initializer);
         }

src/compiler/parser.ts

@@ -126,8 +126,8 @@ namespace ts {
             case SyntaxKind.BindingElement:
                 return visitNodes(cbNode, cbNodes, node.decorators) ||
                     visitNodes(cbNode, cbNodes, node.modifiers) ||
-                    visitNode(cbNode, (<BindingElement>node).propertyName) ||
                     visitNode(cbNode, (<BindingElement>node).dotDotDotToken) ||
+                    visitNode(cbNode, (<BindingElement>node).propertyName) ||
                     visitNode(cbNode, (<BindingElement>node).name) ||
                     visitNode(cbNode, (<BindingElement>node).initializer);
             case SyntaxKind.FunctionType:
@@ -6830,7 +6830,7 @@ namespace ts {
                 }
 
                 function parseTemplateTag(atToken: AtToken, tagName: Identifier): JSDocTemplateTag | undefined {
-                    if (forEach(tags, t => t.kind === SyntaxKind.JSDocTemplateTag)) {
+                    if (some(tags, isJSDocTemplateTag)) {
                         parseErrorAtPosition(tagName.pos, scanner.getTokenPos() - tagName.pos, Diagnostics._0_tag_already_specified, tagName.escapedText);
                     }
 
@@ -6839,14 +6839,14 @@ namespace ts {
                     const typeParametersPos = getNodePos();
 
                     while (true) {
-                        const name = parseJSDocIdentifierName();
+                        const typeParameter = <TypeParameterDeclaration>createNode(SyntaxKind.TypeParameter);
+                        const name = parseJSDocIdentifierNameWithOptionalBraces();
                         skipWhitespace();
                         if (!name) {
                             parseErrorAtPosition(scanner.getStartPos(), 0, Diagnostics.Identifier_expected);
                             return undefined;
                         }
 
-                        const typeParameter = <TypeParameterDeclaration>createNode(SyntaxKind.TypeParameter, name.pos);
                         typeParameter.name = name;
                         finishNode(typeParameter);
 
@@ -6869,6 +6869,15 @@ namespace ts {
                     return result;
                 }
 
+                function parseJSDocIdentifierNameWithOptionalBraces(): Identifier | undefined {
+                    const parsedBrace = parseOptional(SyntaxKind.OpenBraceToken);
+                    const res = parseJSDocIdentifierName();
+                    if (parsedBrace) {
+                        parseExpected(SyntaxKind.CloseBraceToken);
+                    }
+                    return res;
+                }
+
                 function nextJSDocToken(): JsDocSyntaxKind {
                     return currentToken = scanner.scanJSDocToken();
                 }

src/compiler/resolutionCache.ts

@@ -474,11 +474,6 @@ namespace ts {
                     cachedDirectoryStructureHost.addOrDeleteFileOrDirectory(fileOrDirectory, fileOrDirectoryPath);
                 }
 
-                // Ignore emits from the program
-                if (isEmittedFileOfProgram(resolutionHost.getCurrentProgram(), fileOrDirectory)) {
-                    return;
-                }
-
                 // If the files are added to project root or node_modules directory, always run through the invalidation process
                 // Otherwise run through invalidation only if adding to the immediate directory
                 if (!allFilesHaveInvalidatedResolution &&
@@ -582,6 +577,10 @@ namespace ts {
                     if (!isPathWithDefaultFailedLookupExtension(fileOrDirectoryPath) && !customFailedLookupPaths.has(fileOrDirectoryPath)) {
                         return false;
                     }
+                    // Ignore emits from the program
+                    if (isEmittedFileOfProgram(resolutionHost.getCurrentProgram(), fileOrDirectoryPath)) {
+                        return false;
+                    }
                     // Resolution need to be invalidated if failed lookup location is same as the file or directory getting created
                     isChangedFailedLookupLocation = location => resolutionHost.toPath(location) === fileOrDirectoryPath;
                 }

src/compiler/utilities.ts

@@ -2029,7 +2029,13 @@ namespace ts {
         return token !== undefined && isNonContextualKeyword(token);
     }
 
-    export function isTrivia(token: SyntaxKind) {
+    export type TriviaKind = SyntaxKind.SingleLineCommentTrivia
+        | SyntaxKind.MultiLineCommentTrivia
+        | SyntaxKind.NewLineTrivia
+        | SyntaxKind.WhitespaceTrivia
+        | SyntaxKind.ShebangTrivia
+        | SyntaxKind.ConflictMarkerTrivia;
+    export function isTrivia(token: SyntaxKind): token is TriviaKind {
         return SyntaxKind.FirstTriviaToken <= token && token <= SyntaxKind.LastTriviaToken;
     }
 

src/harness/externalCompileRunner.ts

@@ -33,12 +33,15 @@ abstract class ExternalCompileRunnerBase extends RunnerBase {
         });
     }
     private runTest(directoryName: string) {
-        describe(directoryName, () => {
+        // tslint:disable-next-line:no-this-assignment
+        const cls = this;
+        const timeout = 600_000; // 10 minutes
+        describe(directoryName, function(this: Mocha.ISuiteCallbackContext) {
+            this.timeout(timeout);
             const cp = require("child_process");
 
             it("should build successfully", () => {
-                let cwd = path.join(__dirname, "../../", this.testDir, directoryName);
-                const timeout = 600000; // 600s = 10 minutes
+                let cwd = path.join(__dirname, "../../", cls.testDir, directoryName);
                 const stdio = isWorker ? "pipe" : "inherit";
                 let types: string[];
                 if (fs.existsSync(path.join(cwd, "test.json"))) {
@@ -61,18 +64,18 @@ abstract class ExternalCompileRunnerBase extends RunnerBase {
                         fs.unlinkSync(path.join(cwd, "package-lock.json"));
                     }
                     if (fs.existsSync(path.join(cwd, "node_modules"))) {
-                        require("del").sync(path.join(cwd, "node_modules"));
+                        require("del").sync(path.join(cwd, "node_modules"), { force: true });
                     }
-                    const install = cp.spawnSync(`npm`, ["i"], { cwd, timeout, shell: true, stdio });
+                    const install = cp.spawnSync(`npm`, ["i"], { cwd, timeout: timeout / 2, shell: true, stdio }); // NPM shouldn't take the entire timeout - if it takes a long time, it should be terminated and we should log the failure
                     if (install.status !== 0) throw new Error(`NPM Install for ${directoryName} failed: ${install.stderr.toString()}`);
                 }
                 const args = [path.join(__dirname, "tsc.js")];
                 if (types) {
                     args.push("--types", types.join(","));
                 }
                 args.push("--noEmit");
-                Harness.Baseline.runBaseline(`${this.kind()}/${directoryName}.log`, () => {
-                    return this.report(cp.spawnSync(`node`, args, { cwd, timeout, shell: true }), cwd);
+                Harness.Baseline.runBaseline(`${cls.kind()}/${directoryName}.log`, () => {
+                    return cls.report(cp.spawnSync(`node`, args, { cwd, timeout, shell: true }), cwd);
                 });
             });
         });