Merge branch 'master' into fix32349

Author: ahejlsberg

src/compiler/checker.ts

@@ -4635,6 +4635,11 @@
         "category": "Suggestion",
         "code": 80006
     },
+    "'await' has no effect on the type of this expression.": {
+        "category": "Suggestion",
+        "code": 80007
+    },
+
     "Add missing 'super()' call": {
         "category": "Message",
         "code": 90001
@@ -5095,15 +5100,19 @@
         "category": "Message",
         "code": 95085
     },
+    "Remove unnecessary 'await'": {
+        "category": "Message",
+        "code": 95086
+    },
+    "Remove all unnecessary uses of 'await'": {
+        "category": "Message",
+        "code": 95087
+    },
 
     "No value exists in scope for the shorthand property '{0}'. Either declare one or provide an initializer.": {
         "category": "Error",
         "code": 18004
     },
-    "Quoted constructors have previously been interpreted as methods, which is incorrect. In TypeScript 3.6, they will be correctly parsed as constructors. In the meantime, consider using 'constructor()' to write a constructor, or '[\"constructor\"]()' to write a method.": {
-        "category": "Error",
-        "code": 18005
-    },
     "Classes may not have a field named 'constructor'.": {
         "category": "Error",
         "code": 18006

src/compiler/diagnosticMessages.json

@@ -411,7 +411,11 @@ namespace ts {
                     }
                 );
                 if (emitOnlyDtsFiles && declarationTransform.transformed[0].kind === SyntaxKind.SourceFile) {
-                    const sourceFile = declarationTransform.transformed[0] as SourceFile;
+                    // Improved narrowing in master/3.6 makes this cast unnecessary, triggering a lint rule.
+                    // But at the same time, the LKG (3.5) necessitates it because it doesn’t narrow.
+                    // Once the LKG is updated to 3.6, this comment, the cast to `SourceFile`, and the
+                    // tslint directive can be all be removed.
+                    const sourceFile = declarationTransform.transformed[0] as SourceFile; // tslint:disable-line
                     exportedModulesFromDeclarationEmit = sourceFile.exportedModulesFromDeclarationEmit;
                 }
             }

src/compiler/emitter.ts

@@ -4701,7 +4701,7 @@ namespace ts {
         }
     }
 
-    function getLeftmostExpression(node: Expression, stopAtCallExpressions: boolean) {
+    export function getLeftmostExpression(node: Expression, stopAtCallExpressions: boolean) {
         while (true) {
             switch (node.kind) {
                 case SyntaxKind.PostfixUnaryExpression:

src/compiler/factory.ts

@@ -5656,12 +5656,27 @@ namespace ts {
             return finishNode(node);
         }
 
-        function parseConstructorDeclaration(node: ConstructorDeclaration): ConstructorDeclaration {
-            node.kind = SyntaxKind.Constructor;
-            parseExpected(SyntaxKind.ConstructorKeyword);
-            fillSignature(SyntaxKind.ColonToken, SignatureFlags.None, node);
-            node.body = parseFunctionBlockOrSemicolon(SignatureFlags.None, Diagnostics.or_expected);
-            return finishNode(node);
+        function parseConstructorName() {
+            if (token() === SyntaxKind.ConstructorKeyword) {
+                return parseExpected(SyntaxKind.ConstructorKeyword);
+            }
+            if (token() === SyntaxKind.StringLiteral && lookAhead(nextToken) === SyntaxKind.OpenParenToken) {
+                return tryParse(() => {
+                    const literalNode = parseLiteralNode();
+                    return literalNode.text === "constructor" ? literalNode : undefined;
+                });
+            }
+        }
+
+        function tryParseConstructorDeclaration(node: ConstructorDeclaration): ConstructorDeclaration | undefined {
+            return tryParse(() => {
+                if (parseConstructorName()) {
+                    node.kind = SyntaxKind.Constructor;
+                    fillSignature(SyntaxKind.ColonToken, SignatureFlags.None, node);
+                    node.body = parseFunctionBlockOrSemicolon(SignatureFlags.None, Diagnostics.or_expected);
+                    return finishNode(node);
+                }
+            });
         }
 
         function parseMethodDeclaration(node: MethodDeclaration, asteriskToken: AsteriskToken, diagnosticMessage?: DiagnosticMessage): MethodDeclaration {
@@ -5867,8 +5882,11 @@ namespace ts {
                 return parseAccessorDeclaration(<AccessorDeclaration>node, SyntaxKind.SetAccessor);
             }
 
-            if (token() === SyntaxKind.ConstructorKeyword) {
-                return parseConstructorDeclaration(<ConstructorDeclaration>node);
+            if (token() === SyntaxKind.ConstructorKeyword || token() === SyntaxKind.StringLiteral) {
+                const constructorDeclaration = tryParseConstructorDeclaration(<ConstructorDeclaration>node);
+                if (constructorDeclaration) {
+                    return constructorDeclaration;
+                }
             }
 
             if (isIndexSignature()) {

src/compiler/parser.ts

@@ -197,6 +197,7 @@ namespace ts {
         "|=": SyntaxKind.BarEqualsToken,
         "^=": SyntaxKind.CaretEqualsToken,
         "@": SyntaxKind.AtToken,
+        "`": SyntaxKind.BacktickToken
     });
 
     /*
@@ -298,7 +299,6 @@ namespace ts {
     }
 
     const tokenStrings = makeReverseMap(textToToken);
-
     export function tokenToString(t: SyntaxKind): string | undefined {
         return tokenStrings[t];
     }

src/compiler/scanner.ts

@@ -775,10 +775,11 @@ namespace ts {
         priority: 5,
         text: `
             var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+                function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
                 return new (P || (P = Promise))(function (resolve, reject) {
                     function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
                     function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
-                    function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+                    function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
                     step((generator = generator.apply(thisArg, _arguments || [])).next());
                 });
             };`

src/compiler/transformers/es2017.ts

@@ -229,14 +229,39 @@ namespace ts {
             if (node.transformFlags & TransformFlags.ContainsObjectRestOrSpread) {
                 // spread elements emit like so:
                 // non-spread elements are chunked together into object literals, and then all are passed to __assign:
-                //     { a, ...o, b } => __assign({a}, o, {b});
+                //     { a, ...o, b } => __assign(__assign({a}, o), {b});
                 // If the first element is a spread element, then the first argument to __assign is {}:
-                //     { ...o, a, b, ...o2 } => __assign({}, o, {a, b}, o2)
+                //     { ...o, a, b, ...o2 } => __assign(__assign(__assign({}, o), {a, b}), o2)
+                //
+                // We cannot call __assign with more than two elements, since any element could cause side effects. For
+                // example:
+                //      var k = { a: 1, b: 2 };
+                //      var o = { a: 3, ...k, b: k.a++ };
+                //      // expected: { a: 1, b: 1 }
+                // If we translate the above to `__assign({ a: 3 }, k, { b: k.a++ })`, the `k.a++` will evaluate before
+                // `k` is spread and we end up with `{ a: 2, b: 1 }`.
+                //
+                // This also occurs for spread elements, not just property assignments:
+                //      var k = { a: 1, get b() { l = { z: 9 }; return 2; } };
+                //      var l = { c: 3 };
+                //      var o = { ...k, ...l };
+                //      // expected: { a: 1, b: 2, z: 9 }
+                // If we translate the above to `__assign({}, k, l)`, the `l` will evaluate before `k` is spread and we
+                // end up with `{ a: 1, b: 2, c: 3 }`
                 const objects = chunkObjectLiteralElements(node.properties);
                 if (objects.length && objects[0].kind !== SyntaxKind.ObjectLiteralExpression) {
                     objects.unshift(createObjectLiteral());
                 }
-                return createAssignHelper(context, objects);
+                let expression: Expression = objects[0];
+                if (objects.length > 1) {
+                    for (let i = 1; i < objects.length; i++) {
+                        expression = createAssignHelper(context, [expression, objects[i]]);
+                    }
+                    return expression;
+                }
+                else {
+                    return createAssignHelper(context, objects);
+                }
             }
             return visitEachChild(node, visitor, context);
         }

src/compiler/transformers/es2018.ts

@@ -1882,6 +1882,7 @@ namespace ts {
     }
 
     export interface JsxAttributes extends ObjectLiteralExpressionBase<JsxAttributeLike> {
+        kind: SyntaxKind.JsxAttributes;
         parent: JsxOpeningLikeElement;
     }
 
@@ -4759,7 +4760,7 @@ namespace ts {
         UMD = 3,
         System = 4,
         ES2015 = 5,
-        ESNext = 6
+        ESNext = 99
     }
 
     export const enum JsxEmit {
@@ -4807,7 +4808,7 @@ namespace ts {
         ES2018 = 5,
         ES2019 = 6,
         ES2020 = 7,
-        ESNext = 8,
+        ESNext = 99,
         JSON = 100,
         Latest = ESNext,
     }

src/compiler/types.ts

@@ -3150,6 +3150,23 @@ namespace ts {
         return s.replace(escapedCharsRegExp, getReplacement);
     }
 
+    /**
+     * Strip off existed single quotes or double quotes from a given string
+     *
+     * @return non-quoted string
+     */
+    export function stripQuotes(name: string) {
+        const length = name.length;
+        if (length >= 2 && name.charCodeAt(0) === name.charCodeAt(length - 1) && startsWithQuote(name)) {
+            return name.substring(1, length - 1);
+        }
+        return name;
+    }
+
+    export function startsWithQuote(name: string): boolean {
+        return isSingleOrDoubleQuote(name.charCodeAt(0));
+    }
+
     function getReplacement(c: string, offset: number, input: string) {
         if (c.charCodeAt(0) === CharacterCodes.nullCharacter) {
             const lookAhead = input.charCodeAt(offset + c.length);
@@ -7468,7 +7485,7 @@ namespace ts {
     export function getDirectoryPath(path: Path): Path;
     /**
      * Returns the path except for its basename. Semantics align with NodeJS's `path.dirname`
-     * except that we support URLs as well.
+     * except that we support URL's as well.
      *
      * ```ts
      * getDirectoryPath("/path/to/file.ext") === "/path/to"