Merge branch 'master' into release-2.7

src/compiler/binder.ts

@@ -2289,30 +2289,13 @@ namespace ts {
             declareSymbol(file.symbol.exports, file.symbol, <PropertyAccessExpression>node.left, SymbolFlags.Property | SymbolFlags.ExportValue, SymbolFlags.None);
         }
 
-        function isExportsOrModuleExportsOrAlias(node: Node): boolean {
-            return isExportsIdentifier(node) ||
-                isModuleExportsPropertyAccessExpression(node) ||
-                isIdentifier(node) && isNameOfExportsOrModuleExportsAliasDeclaration(node);
-        }
-
-        function isNameOfExportsOrModuleExportsAliasDeclaration(node: Identifier): boolean {
-            const symbol = lookupSymbolForName(node.escapedText);
-            return symbol && symbol.valueDeclaration && isVariableDeclaration(symbol.valueDeclaration) &&
-                symbol.valueDeclaration.initializer && isExportsOrModuleExportsOrAliasOrAssignment(symbol.valueDeclaration.initializer);
-        }
-
-        function isExportsOrModuleExportsOrAliasOrAssignment(node: Node): boolean {
-            return isExportsOrModuleExportsOrAlias(node) ||
-                (isAssignmentExpression(node, /*excludeCompoundAssignements*/ true) && (isExportsOrModuleExportsOrAliasOrAssignment(node.left) || isExportsOrModuleExportsOrAliasOrAssignment(node.right)));
-        }
-
         function bindModuleExportsAssignment(node: BinaryExpression) {
             // A common practice in node modules is to set 'export = module.exports = {}', this ensures that 'exports'
             // is still pointing to 'module.exports'.
             // We do not want to consider this as 'export=' since a module can have only one of these.
             // Similarly we do not want to treat 'module.exports = exports' as an 'export='.
             const assignedExpression = getRightMostAssignedExpression(node.right);
-            if (isEmptyObjectLiteral(assignedExpression) || isExportsOrModuleExportsOrAlias(assignedExpression)) {
+            if (isEmptyObjectLiteral(assignedExpression) || container === file && isExportsOrModuleExportsOrAlias(file, assignedExpression)) {
                 // Mark it as a module in case there are no other exports in the file
                 setCommonJsModuleIndicator(node);
                 return;
@@ -2393,7 +2376,7 @@ namespace ts {
                 if (node.kind === SyntaxKind.BinaryExpression) {
                     leftSideOfAssignment.parent = node;
                 }
-                if (isNameOfExportsOrModuleExportsAliasDeclaration(target)) {
+                if (container === file && isNameOfExportsOrModuleExportsAliasDeclaration(file, target)) {
                     // This can be an alias for the 'exports' or 'module.exports' names, e.g.
                     //    var util = module.exports;
                     //    util.property = function ...
@@ -2406,11 +2389,7 @@ namespace ts {
         }
 
         function lookupSymbolForName(name: __String) {
-            const local = container.locals && container.locals.get(name);
-            if (local) {
-                return local.exportSymbol || local;
-            }
-            return container.symbol && container.symbol.exports && container.symbol.exports.get(name);
+            return lookupSymbolForNameWorker(container, name);
         }
 
         function bindPropertyAssignment(functionName: __String, propertyAccess: PropertyAccessExpression, isPrototypeProperty: boolean) {
@@ -2649,6 +2628,33 @@ namespace ts {
         }
     }
 
+    /* @internal */
+    export function isExportsOrModuleExportsOrAlias(sourceFile: SourceFile, node: Expression): boolean {
+        return isExportsIdentifier(node) ||
+            isModuleExportsPropertyAccessExpression(node) ||
+            isIdentifier(node) && isNameOfExportsOrModuleExportsAliasDeclaration(sourceFile, node);
+    }
+
+    function isNameOfExportsOrModuleExportsAliasDeclaration(sourceFile: SourceFile, node: Identifier): boolean {
+        const symbol = lookupSymbolForNameWorker(sourceFile, node.escapedText);
+        return symbol && symbol.valueDeclaration && isVariableDeclaration(symbol.valueDeclaration) &&
+            symbol.valueDeclaration.initializer && isExportsOrModuleExportsOrAliasOrAssignment(sourceFile, symbol.valueDeclaration.initializer);
+    }
+
+    function isExportsOrModuleExportsOrAliasOrAssignment(sourceFile: SourceFile, node: Expression): boolean {
+        return isExportsOrModuleExportsOrAlias(sourceFile, node) ||
+            (isAssignmentExpression(node, /*excludeCompoundAssignements*/ true) && (
+                isExportsOrModuleExportsOrAliasOrAssignment(sourceFile, node.left) || isExportsOrModuleExportsOrAliasOrAssignment(sourceFile, node.right)));
+    }
+
+    function lookupSymbolForNameWorker(container: Node, name: __String): Symbol | undefined {
+        const local = container.locals && container.locals.get(name);
+        if (local) {
+            return local.exportSymbol || local;
+        }
+        return container.symbol && container.symbol.exports && container.symbol.exports.get(name);
+    }
+
     /**
      * Computes the transform flags for a node, given the transform flags of its subtree
      *

src/compiler/checker.ts

@@ -268,8 +268,8 @@ namespace ts {
             getSuggestionForNonexistentSymbol: (location, name, meaning) => getSuggestionForNonexistentSymbol(location, escapeLeadingUnderscores(name), meaning),
             getBaseConstraintOfType,
             getDefaultFromTypeParameter: type => type && type.flags & TypeFlags.TypeParameter ? getDefaultFromTypeParameter(type as TypeParameter) : undefined,
-            resolveName(name, location, meaning) {
-                return resolveName(location, escapeLeadingUnderscores(name), meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false);
+            resolveName(name, location, meaning, excludeGlobals) {
+                return resolveName(location, escapeLeadingUnderscores(name), meaning, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false, excludeGlobals);
             },
             getJsxNamespace: () => unescapeLeadingUnderscores(getJsxNamespace()),
             getAccessibleSymbolChain,
@@ -952,8 +952,9 @@ namespace ts {
             nameNotFoundMessage: DiagnosticMessage | undefined,
             nameArg: __String | Identifier,
             isUse: boolean,
+            excludeGlobals = false,
             suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol {
-            return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, getSymbol, suggestedNameNotFoundMessage);
+            return resolveNameHelper(location, name, meaning, nameNotFoundMessage, nameArg, isUse, excludeGlobals, getSymbol, suggestedNameNotFoundMessage);
         }
 
         function resolveNameHelper(
@@ -963,6 +964,7 @@ namespace ts {
             nameNotFoundMessage: DiagnosticMessage,
             nameArg: __String | Identifier,
             isUse: boolean,
+            excludeGlobals: boolean,
             lookup: typeof getSymbol,
             suggestedNameNotFoundMessage?: DiagnosticMessage): Symbol {
             const originalLocation = location; // needed for did-you-mean error reporting, which gathers candidates starting from the original location
@@ -1209,7 +1211,9 @@ namespace ts {
                     }
                 }
 
-                result = lookup(globals, name, meaning);
+                if (!excludeGlobals) {
+                    result = lookup(globals, name, meaning);
+                }
             }
 
             if (!result) {
@@ -11277,6 +11281,9 @@ namespace ts {
                     }
                     diagnostic = Diagnostics._0_which_lacks_return_type_annotation_implicitly_has_an_1_return_type;
                     break;
+                case SyntaxKind.MappedType:
+                    error(declaration, Diagnostics.Mapped_object_type_implicitly_has_an_any_template_type);
+                    return;
                 default:
                     diagnostic = Diagnostics.Variable_0_implicitly_has_an_1_type;
             }
@@ -11889,6 +11896,7 @@ namespace ts {
                         Diagnostics.Cannot_find_name_0,
                         node,
                         !isWriteOnlyAccess(node),
+                        /*excludeGlobals*/ false,
                         Diagnostics.Cannot_find_name_0_Did_you_mean_1) || unknownSymbol;
             }
             return links.resolvedSymbol;
@@ -15154,7 +15162,7 @@ namespace ts {
          * element is not a class element, or the class element type cannot be determined, returns 'undefined'.
          * For example, in the element <MyClass>, the element instance type is `MyClass` (not `typeof MyClass`).
          */
-        function getJsxElementInstanceType(node: JsxOpeningLikeElement, valueType: Type, sourceAttributesType: Type) {
+        function getJsxElementInstanceType(node: JsxOpeningLikeElement, valueType: Type, sourceAttributesType: Type | undefined) {
             Debug.assert(!(valueType.flags & TypeFlags.Union));
             if (isTypeAny(valueType)) {
                 // Short-circuit if the class tag is using an element type 'any'
@@ -15173,20 +15181,27 @@ namespace ts {
                 }
             }
 
-            const instantiatedSignatures = [];
-            for (const signature of signatures) {
-                if (signature.typeParameters) {
-                    const isJavascript = isInJavaScriptFile(node);
-                    const inferenceContext = createInferenceContext(signature, /*flags*/ isJavascript ? InferenceFlags.AnyDefault : 0);
-                    const typeArguments = inferJsxTypeArguments(signature, sourceAttributesType, inferenceContext);
-                    instantiatedSignatures.push(getSignatureInstantiation(signature, typeArguments, isJavascript));
+            if (sourceAttributesType) {
+                // Instantiate in context of source type
+                const instantiatedSignatures = [];
+                for (const signature of signatures) {
+                    if (signature.typeParameters) {
+                        const isJavascript = isInJavaScriptFile(node);
+                        const inferenceContext = createInferenceContext(signature, /*flags*/ isJavascript ? InferenceFlags.AnyDefault : 0);
+                        const typeArguments = inferJsxTypeArguments(signature, sourceAttributesType, inferenceContext);
+                        instantiatedSignatures.push(getSignatureInstantiation(signature, typeArguments, isJavascript));
+                    }
+                    else {
+                        instantiatedSignatures.push(signature);
+                    }
                 }
-                else {
-                    instantiatedSignatures.push(signature);
-                }
-            }
 
-            return getUnionType(map(instantiatedSignatures, getReturnTypeOfSignature), UnionReduction.Subtype);
+                return getUnionType(map(instantiatedSignatures, getReturnTypeOfSignature), UnionReduction.Subtype);
+            }
+            else {
+                // Do not instantiate if no source type is provided - type parameters and their constraints will be used by contextual typing
+                return getUnionType(map(signatures, getReturnTypeOfSignature), UnionReduction.Subtype);
+            }
         }
 
         /**
@@ -15410,7 +15425,7 @@ namespace ts {
             }
 
             // Get the element instance type (the result of newing or invoking this tag)
-            const elemInstanceType = getJsxElementInstanceType(openingLikeElement, elementType, sourceAttributesType || emptyObjectType);
+            const elemInstanceType = getJsxElementInstanceType(openingLikeElement, elementType, sourceAttributesType);
 
             // If we should include all stateless attributes type, then get all attributes type from all stateless function signature.
             // Otherwise get only attributes type from the signature picked by choose-overload logic.
@@ -16068,7 +16083,7 @@ namespace ts {
 
         function getSuggestionForNonexistentSymbol(location: Node, outerName: __String, meaning: SymbolFlags): string {
             Debug.assert(outerName !== undefined, "outername should always be defined");
-            const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, (symbols, name, meaning) => {
+            const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, /*excludeGlobals*/ false, (symbols, name, meaning) => {
                 Debug.assertEqual(outerName, name, "name should equal outerName");
                 const symbol = getSymbol(symbols, name, meaning);
                 // Sometimes the symbol is found when location is a return type of a function: `typeof x` and `x` is declared in the body of the function
@@ -20307,6 +20322,11 @@ namespace ts {
         function checkMappedType(node: MappedTypeNode) {
             checkSourceElement(node.typeParameter);
             checkSourceElement(node.type);
+
+            if (noImplicitAny && !node.type) {
+                reportImplicitAnyError(node, anyType);
+            }
+
             const type = <MappedType>getTypeFromMappedTypeNode(node);
             const constraintType = getConstraintTypeFromMappedType(type);
             checkTypeAssignableTo(constraintType, stringType, node.typeParameter.constraint);
@@ -22985,7 +23005,7 @@ namespace ts {
                             Diagnostics.Property_0_in_type_1_is_not_assignable_to_the_same_property_in_base_type_2,
                             unescapeLeadingUnderscores(declaredProp.escapedName),
                             typeToString(typeWithThis),
-                            typeToString(getTypeOfSymbol(baseProp))
+                            typeToString(baseWithThis)
                         );
                         if (!checkTypeAssignableTo(getTypeOfSymbol(prop), getTypeOfSymbol(baseProp), member.name || member, /*message*/ undefined, rootChain)) {
                             issuedMemberError = true;

src/compiler/core.ts

@@ -412,12 +412,14 @@ namespace ts {
         return result;
     }
 
+
     export function mapIterator<T, U>(iter: Iterator<T>, mapFn: (x: T) => U): Iterator<U> {
-        return { next };
-        function next(): { value: U, done: false } | { value: never, done: true } {
-            const iterRes = iter.next();
-            return iterRes.done ? iterRes : { value: mapFn(iterRes.value), done: false };
-        }
+        return {
+            next() {
+                const iterRes = iter.next();
+                return iterRes.done ? iterRes : { value: mapFn(iterRes.value), done: false };
+            }
+        };
     }
 
     // Maps from T to T and avoids allocation if all elements map to themselves
@@ -551,12 +553,23 @@ namespace ts {
         return result || array;
     }
 
+    export function mapAllOrFail<T, U>(array: ReadonlyArray<T>, mapFn: (x: T, i: number) => U | undefined): U[] | undefined {
+        const result: U[] = [];
+        for (let i = 0; i < array.length; i++) {
+            const mapped = mapFn(array[i], i);
+            if (mapped === undefined) {
+                return undefined;
+            }
+            result.push(mapped);
+        }
+        return result;
+    }
+
     export function mapDefined<T, U>(array: ReadonlyArray<T> | undefined, mapFn: (x: T, i: number) => U | undefined): U[] {
         const result: U[] = [];
         if (array) {
             for (let i = 0; i < array.length; i++) {
-                const item = array[i];
-                const mapped = mapFn(item, i);
+                const mapped = mapFn(array[i], i);
                 if (mapped !== undefined) {
                     result.push(mapped);
                 }

src/compiler/diagnosticMessages.json

@@ -3571,7 +3571,10 @@
         "category": "Error",
         "code": 7038
     },
-
+    "Mapped object type implicitly has an 'any' template type.": {
+        "category": "Error",
+        "code": 7039
+    },
     "You cannot rename this element.": {
         "category": "Error",
         "code": 8000
@@ -3874,6 +3877,10 @@
         "category": "Message",
         "code": 90028
     },
+    "Add async modifier to containing function": {
+        "category": "Message",
+        "code": 90029
+    },
     "Convert function to an ES2015 class": {
         "category": "Message",
         "code": 95001
@@ -3937,5 +3944,9 @@
     "Use synthetic 'default' member.": {
         "category": "Message",
         "code": 95016
+    },
+    "Convert to ES6 module": {
+        "category": "Message",
+        "code": 95017
     }
 }

src/compiler/emitter.ts

@@ -1194,27 +1194,15 @@ namespace ts {
         //
 
         function emitObjectBindingPattern(node: ObjectBindingPattern) {
-            const elements = node.elements;
-            if (elements.length === 0) {
-                write("{}");
-            }
-            else {
-                write("{");
-                emitList(node, elements, ListFormat.ObjectBindingPatternElements);
-                write("}");
-            }
+            write("{");
+            emitList(node, node.elements, ListFormat.ObjectBindingPatternElements);
+            write("}");
         }
 
         function emitArrayBindingPattern(node: ArrayBindingPattern) {
-            const elements = node.elements;
-            if (elements.length === 0) {
-                write("[]");
-            }
-            else {
-                write("[");
-                emitList(node, node.elements, ListFormat.ArrayBindingPatternElements);
-                write("]");
-            }
+            write("[");
+            emitList(node, node.elements, ListFormat.ArrayBindingPatternElements);
+            write("]");
         }
 
         function emitBindingElement(node: BindingElement) {
@@ -3167,8 +3155,8 @@ namespace ts {
         TupleTypeElements = CommaDelimited | SpaceBetweenSiblings | SingleLine | Indented,
         UnionTypeConstituents = BarDelimited | SpaceBetweenSiblings | SingleLine,
         IntersectionTypeConstituents = AmpersandDelimited | SpaceBetweenSiblings | SingleLine,
-        ObjectBindingPatternElements = SingleLine | AllowTrailingComma | SpaceBetweenBraces | CommaDelimited | SpaceBetweenSiblings,
-        ArrayBindingPatternElements = SingleLine | AllowTrailingComma | CommaDelimited | SpaceBetweenSiblings,
+        ObjectBindingPatternElements = SingleLine | AllowTrailingComma | SpaceBetweenBraces | CommaDelimited | SpaceBetweenSiblings | NoSpaceIfEmpty,
+        ArrayBindingPatternElements = SingleLine | AllowTrailingComma | CommaDelimited | SpaceBetweenSiblings | NoSpaceIfEmpty,
         ObjectLiteralExpressionProperties = PreserveLines | CommaDelimited | SpaceBetweenSiblings | SpaceBetweenBraces | Indented | Braces | NoSpaceIfEmpty,
         ArrayLiteralExpressionElements = PreserveLines | CommaDelimited | SpaceBetweenSiblings | AllowTrailingComma | Indented | SquareBrackets,
         CommaListElements = CommaDelimited | SpaceBetweenSiblings | SingleLine,

src/compiler/factory.ts

@@ -71,11 +71,11 @@ namespace ts {
     // Literals
 
     /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
-    export function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
+    export function createLiteral(value: string | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier): StringLiteral;
     export function createLiteral(value: number): NumericLiteral;
     export function createLiteral(value: boolean): BooleanLiteral;
     export function createLiteral(value: string | number | boolean): PrimaryExpression;
-    export function createLiteral(value: string | number | boolean | StringLiteral | NumericLiteral | Identifier): PrimaryExpression {
+    export function createLiteral(value: string | number | boolean | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier): PrimaryExpression {
         if (typeof value === "number") {
             return createNumericLiteral(value + "");
         }
@@ -101,7 +101,7 @@ namespace ts {
         return node;
     }
 
-    function createLiteralFromNode(sourceNode: StringLiteral | NumericLiteral | Identifier): StringLiteral {
+    function createLiteralFromNode(sourceNode: StringLiteralLike | NumericLiteral | Identifier): StringLiteral {
         const node = createStringLiteral(getTextOfIdentifierOrLiteral(sourceNode));
         node.textSourceNode = sourceNode;
         return node;
@@ -3626,7 +3626,7 @@ namespace ts {
         return qualifiedName;
     }
 
-    export function convertToFunctionBody(node: ConciseBody, multiLine?: boolean) {
+    export function convertToFunctionBody(node: ConciseBody, multiLine?: boolean): Block {
         return isBlock(node) ? node : setTextRange(createBlock([setTextRange(createReturn(node), node)], multiLine), node);
     }
 

src/compiler/parser.ts

@@ -786,15 +786,7 @@ namespace ts {
             const comments = getJSDocCommentRanges(node, sourceFile.text);
             if (comments) {
                 for (const comment of comments) {
-                    const jsDoc = JSDocParser.parseJSDocComment(node, comment.pos, comment.end - comment.pos);
-                    if (jsDoc) {
-                        if (!node.jsDoc) {
-                            node.jsDoc = [jsDoc];
-                        }
-                        else {
-                            node.jsDoc.push(jsDoc);
-                        }
-                    }
+                    node.jsDoc = append(node.jsDoc, JSDocParser.parseJSDocComment(node, comment.pos, comment.end - comment.pos));
                 }
             }
 
@@ -6499,7 +6491,7 @@ namespace ts {
                                 if (state === JSDocState.BeginningOfLine) {
                                     // leading asterisks start recording on the *next* (non-whitespace) token
                                     state = JSDocState.SawAsterisk;
-                                    indent += scanner.getTokenText().length;
+                                    indent += 1;
                                     break;
                                 }
                                 // record the * as a comment
@@ -6611,10 +6603,7 @@ namespace ts {
                         const start = scanner.getStartPos();
                         let children: JSDocParameterTag[];
                         while (child = tryParse(() => parseChildParameterOrPropertyTag(PropertyLikeParse.Parameter, name))) {
-                            if (!children) {
-                                children = [];
-                            }
-                            children.push(child);
+                            children = append(children, child);
                         }
                         if (children) {
                             jsdocTypeLiteral = <JSDocTypeLiteral>createNode(SyntaxKind.JSDocTypeLiteral, start);
@@ -6731,10 +6720,7 @@ namespace ts {
                                 }
                             }
                             else {
-                                if (!jsdocTypeLiteral.jsDocPropertyTags) {
-                                    jsdocTypeLiteral.jsDocPropertyTags = [] as MutableNodeArray<JSDocPropertyTag>;
-                                }
-                                (jsdocTypeLiteral.jsDocPropertyTags as MutableNodeArray<JSDocPropertyTag>).push(child);
+                                jsdocTypeLiteral.jsDocPropertyTags = append(jsdocTypeLiteral.jsDocPropertyTags as MutableNodeArray<JSDocPropertyTag>, child);
                             }
                         }
                         if (jsdocTypeLiteral) {

src/compiler/types.ts

@@ -1149,11 +1149,13 @@ namespace ts {
 
     export interface StringLiteral extends LiteralExpression {
         kind: SyntaxKind.StringLiteral;
-        /* @internal */ textSourceNode?: Identifier | StringLiteral | NumericLiteral; // Allows a StringLiteral to get its text from another node (used by transforms).
+        /* @internal */ textSourceNode?: Identifier | StringLiteralLike | NumericLiteral; // Allows a StringLiteral to get its text from another node (used by transforms).
         /** Note: this is only set when synthesizing a node, not during parsing. */
         /* @internal */ singleQuote?: boolean;
     }
 
+    /* @internal */ export type StringLiteralLike = StringLiteral | NoSubstitutionTemplateLiteral;
+
     // Note: 'brands' in our syntax nodes serve to give us a small amount of nominal typing.
     // Consider 'Expression'.  Without the brand, 'Expression' is actually no different
     // (structurally) than 'Node'.  Because of this you can pass any Node to a function that
@@ -1499,6 +1501,7 @@ namespace ts {
         kind: SyntaxKind.ArrowFunction;
         equalsGreaterThanToken: EqualsGreaterThanToken;
         body: ConciseBody;
+        name: never;
     }
 
     // The text property of a LiteralExpression stores the interpreted value of the literal in text form. For a StringLiteral,
@@ -2156,6 +2159,7 @@ namespace ts {
     export interface ExportDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ExportDeclaration;
         parent?: SourceFile | ModuleBlock;
+        /** Will not be assigned in the case of `export * from "foo";` */
         exportClause?: NamedExports;
         /** If this is not a StringLiteral it will be a grammar error. */
         moduleSpecifier?: Expression;
@@ -2878,7 +2882,7 @@ namespace ts {
          */
         /* @internal */ isArrayLikeType(type: Type): boolean;
         /* @internal */ getAllPossiblePropertiesOfTypes(type: ReadonlyArray<Type>): Symbol[];
-        /* @internal */ resolveName(name: string, location: Node, meaning: SymbolFlags): Symbol | undefined;
+        /* @internal */ resolveName(name: string, location: Node, meaning: SymbolFlags, excludeGlobals: boolean): Symbol | undefined;
         /* @internal */ getJsxNamespace(): string;
 
         /**

src/compiler/utilities.ts

@@ -5,6 +5,7 @@ namespace ts {
     export const emptyArray: never[] = [] as never[];
     export const resolvingEmptyArray: never[] = [] as never[];
     export const emptyMap: ReadonlyMap<never> = createMap<never>();
+    export const emptyUnderscoreEscapedMap: ReadonlyUnderscoreEscapedMap<never> = emptyMap as ReadonlyUnderscoreEscapedMap<never>;
 
     export const externalHelpersModuleNameText = "tslib";
 
@@ -1419,6 +1420,8 @@ namespace ts {
      * exactly one argument (of the form 'require("name")').
      * This function does not test if the node is in a JavaScript file or not.
      */
+    export function isRequireCall(callExpression: Node, checkArgumentIsStringLiteral: true): callExpression is CallExpression & { expression: Identifier, arguments: [StringLiteralLike] };
+    export function isRequireCall(callExpression: Node, checkArgumentIsStringLiteral: boolean): callExpression is CallExpression;
     export function isRequireCall(callExpression: Node, checkArgumentIsStringLiteral: boolean): callExpression is CallExpression {
         if (callExpression.kind !== SyntaxKind.CallExpression) {
             return false;
@@ -1456,7 +1459,7 @@ namespace ts {
         return false;
     }
 
-    export function getRightMostAssignedExpression(node: Node) {
+    export function getRightMostAssignedExpression(node: Expression): Expression {
         while (isAssignmentExpression(node, /*excludeCompoundAssignements*/ true)) {
             node = node.right;
         }

src/harness/fourslash.ts

@@ -454,7 +454,7 @@ namespace FourSlash {
             const ranges = this.getRanges();
             assert(ranges.length);
             for (const range of ranges) {
-                this.goToRangeStart(range);
+                this.selectRange(range);
                 action();
             }
         }
@@ -482,6 +482,11 @@ namespace FourSlash {
             this.selectionEnd = end.position;
         }
 
+        public selectRange(range: Range): void {
+            this.goToRangeStart(range);
+            this.selectionEnd = range.end;
+        }
+
         public moveCaretRight(count = 1) {
             this.currentCaretPosition += count;
             this.currentCaretPosition = Math.min(this.currentCaretPosition, this.getFileContent(this.activeFile.fileName).length);
@@ -3835,6 +3840,10 @@ namespace FourSlashInterface {
         public select(startMarker: string, endMarker: string) {
             this.state.select(startMarker, endMarker);
         }
+
+        public selectRange(range: FourSlash.Range): void {
+            this.state.selectRange(range);
+        }
     }
 
     export class VerifyNegatable {

src/harness/unittests/tsserverProjectSystem.ts

@@ -6488,4 +6488,76 @@ namespace ts.projectSystem {
             verifyWatchedDirectories(/*useProjectAtRoot*/ false);
         });
     });
+
+    describe("tsserverProjectSystem typingsInstaller on inferred Project", () => {
+        it("when projectRootPath is provided", () => {
+            const projects = "/users/username/projects";
+            const projectRootPath = `${projects}/san2`;
+            const file: FileOrFolder = {
+                path: `${projectRootPath}/x.js`,
+                content: "const aaaaaaav = 1;"
+            };
+
+            const currentDirectory = `${projects}/anotherProject`;
+            const packageJsonInCurrentDirectory: FileOrFolder = {
+                path: `${currentDirectory}/package.json`,
+                content: JSON.stringify({
+                    devDependencies: {
+                        pkgcurrentdirectory: ""
+                    },
+                })
+            };
+            const packageJsonOfPkgcurrentdirectory: FileOrFolder = {
+                path: `${currentDirectory}/node_modules/pkgcurrentdirectory/package.json`,
+                content: JSON.stringify({
+                    name: "pkgcurrentdirectory",
+                    main: "index.js",
+                    typings: "index.d.ts"
+                })
+            };
+            const indexOfPkgcurrentdirectory: FileOrFolder = {
+                path: `${currentDirectory}/node_modules/pkgcurrentdirectory/index.d.ts`,
+                content: "export function foo() { }"
+            };
+
+            const typingsCache = `/users/username/Library/Caches/typescript/2.7`;
+            const typingsCachePackageJson: FileOrFolder = {
+                path: `${typingsCache}/package.json`,
+                content: JSON.stringify({
+                    devDependencies: {
+                    },
+                })
+            };
+
+            const files = [file, packageJsonInCurrentDirectory, packageJsonOfPkgcurrentdirectory, indexOfPkgcurrentdirectory, typingsCachePackageJson];
+            const host = createServerHost(files, { currentDirectory });
+
+            const typesRegistry = createMap<void>();
+            typesRegistry.set("pkgcurrentdirectory", void 0);
+            const typingsInstaller = new TestTypingsInstaller(typingsCache, /*throttleLimit*/ 5, host, typesRegistry);
+
+            const projectService = createProjectService(host, { typingsInstaller });
+
+            projectService.setCompilerOptionsForInferredProjects({
+                module: ModuleKind.CommonJS,
+                target: ScriptTarget.ES2016,
+                jsx: JsxEmit.Preserve,
+                experimentalDecorators: true,
+                allowJs: true,
+                allowSyntheticDefaultImports: true,
+                allowNonTsExtensions: true
+            });
+
+            projectService.openClientFile(file.path, file.content, ScriptKind.JS, projectRootPath);
+
+            const project = projectService.inferredProjects[0];
+            assert.isDefined(project);
+
+            // Ensure that we use result from types cache when getting ls
+            assert.isDefined(project.getLanguageService());
+
+            // Verify that the pkgcurrentdirectory from the current directory isnt picked up
+            checkProjectActualFiles(project, [file.path]);
+        });
+    });
 }

src/harness/virtualFileSystemWithWatch.ts

@@ -547,7 +547,7 @@ interface Array<T> {}`
         }
 
         readDirectory(path: string, extensions?: ReadonlyArray<string>, exclude?: ReadonlyArray<string>, include?: ReadonlyArray<string>, depth?: number): string[] {
-            return ts.matchFiles(this.toNormalizedAbsolutePath(path), extensions, exclude, include, this.useCaseSensitiveFileNames, this.getCurrentDirectory(), depth, (dir) => {
+            return ts.matchFiles(path, extensions, exclude, include, this.useCaseSensitiveFileNames, this.getCurrentDirectory(), depth, (dir) => {
                 const directories: string[] = [];
                 const files: string[] = [];
                 const dirEntry = this.fs.get(this.toPath(dir));

src/lib/es2015.collection.d.ts

@@ -58,7 +58,7 @@ interface ReadonlySet<T> {
     readonly size: number;
 }
 
-interface WeakSet<T> {
+interface WeakSet<T extends object> {
     add(value: T): this;
     delete(value: T): boolean;
     has(value: T): boolean;

src/lib/es2015.iterable.d.ts

@@ -180,7 +180,7 @@ interface SetConstructor {
     new <T>(iterable: Iterable<T>): Set<T>;
 }
 
-interface WeakSet<T> { }
+interface WeakSet<T extends object> { }
 
 interface WeakSetConstructor {
     new <T extends object>(iterable: Iterable<T>): WeakSet<T>;

src/lib/es2015.symbol.wellknown.d.ts

@@ -118,7 +118,7 @@ interface Set<T> {
     readonly [Symbol.toStringTag]: "Set";
 }
 
-interface WeakSet<T> {
+interface WeakSet<T extends object> {
     readonly [Symbol.toStringTag]: "WeakSet";
 }
 

src/server/utilities.ts

@@ -34,19 +34,6 @@ namespace ts.server {
         export type Types = Msg;
     }
 
-    function getProjectRootPath(project: Project): Path {
-        switch (project.projectKind) {
-            case ProjectKind.Configured:
-                return <Path>getDirectoryPath(project.getProjectName());
-            case ProjectKind.Inferred:
-                // TODO: fixme
-                return <Path>"";
-            case ProjectKind.External:
-                const projectName = normalizeSlashes(project.getProjectName());
-                return <Path>getDirectoryPath(projectName);
-        }
-    }
-
     export function createInstallTypingsRequest(project: Project, typeAcquisition: TypeAcquisition, unresolvedImports: SortedReadonlyArray<string>, cachePath?: string): DiscoverTypings {
         return {
             projectName: project.getProjectName(),
@@ -54,7 +41,7 @@ namespace ts.server {
             compilerOptions: project.getCompilationSettings(),
             typeAcquisition,
             unresolvedImports,
-            projectRootPath: getProjectRootPath(project),
+            projectRootPath: project.getCurrentDirectory() as Path,
             cachePath,
             kind: "discover"
         };

src/services/codefixes/fixAwaitInSyncFunction.ts

@@ -0,0 +1,74 @@
+/* @internal */
+namespace ts.codefix {
+    const fixId = "fixAwaitInSyncFunction";
+    const errorCodes = [
+        Diagnostics.await_expression_is_only_allowed_within_an_async_function.code,
+        Diagnostics.A_for_await_of_statement_is_only_allowed_within_an_async_function_or_async_generator.code,
+    ];
+    registerCodeFix({
+        errorCodes,
+        getCodeActions(context) {
+            const { sourceFile, span } = context;
+            const nodes = getNodes(sourceFile, span.start);
+            if (!nodes) return undefined;
+            const changes = textChanges.ChangeTracker.with(context, t => doChange(t, sourceFile, nodes));
+            return [{ description: getLocaleSpecificMessage(Diagnostics.Add_async_modifier_to_containing_function), changes, fixId }];
+        },
+        fixIds: [fixId],
+        getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => {
+            const nodes = getNodes(diag.file, diag.start);
+            if (!nodes) return;
+            doChange(changes, context.sourceFile, nodes);
+        }),
+    });
+
+    function getReturnType(expr: FunctionDeclaration | MethodDeclaration | FunctionExpression | ArrowFunction) {
+        if (expr.type) {
+            return expr.type;
+        }
+        if (isVariableDeclaration(expr.parent) &&
+            expr.parent.type &&
+            isFunctionTypeNode(expr.parent.type)) {
+            return expr.parent.type.type;
+        }
+    }
+
+    function getNodes(sourceFile: SourceFile, start: number): { insertBefore: Node, returnType: TypeNode | undefined } | undefined {
+        const token = getTokenAtPosition(sourceFile, start, /*includeJsDocComment*/ false);
+        const containingFunction = getContainingFunction(token);
+        let insertBefore: Node | undefined;
+        switch (containingFunction.kind) {
+            case SyntaxKind.MethodDeclaration:
+                insertBefore = containingFunction.name;
+                break;
+            case SyntaxKind.FunctionDeclaration:
+            case SyntaxKind.FunctionExpression:
+                insertBefore = findChildOfKind(containingFunction, SyntaxKind.FunctionKeyword, sourceFile);
+                break;
+            case SyntaxKind.ArrowFunction:
+                insertBefore = findChildOfKind(containingFunction, SyntaxKind.OpenParenToken, sourceFile) || first(containingFunction.parameters);
+                break;
+            default:
+                return;
+        }
+
+        return {
+            insertBefore,
+            returnType: getReturnType(containingFunction)
+        };
+    }
+
+    function doChange(
+        changes: textChanges.ChangeTracker,
+        sourceFile: SourceFile,
+        { insertBefore, returnType }: { insertBefore: Node | undefined, returnType: TypeNode | undefined }): void {
+
+        if (returnType) {
+            const entityName = getEntityNameFromTypeNode(returnType);
+            if (!entityName || entityName.kind !== SyntaxKind.Identifier || entityName.text !== "Promise") {
+                changes.replaceNode(sourceFile, returnType, createTypeReferenceNode("Promise", createNodeArray([returnType])));
+            }
+        }
+        changes.insertModifierBefore(sourceFile, SyntaxKind.AsyncKeyword, insertBefore);
+    }
+}

src/services/codefixes/fixes.ts

@@ -11,6 +11,7 @@
 /// <reference path="fixForgottenThisPropertyAccess.ts" />
 /// <reference path='fixUnusedIdentifier.ts' />
 /// <reference path='fixJSDocTypes.ts' />
+/// <reference path='fixAwaitInSyncFunction.ts' />
 /// <reference path='importFixes.ts' />
 /// <reference path='disableJsDiagnostics.ts' />
 /// <reference path='helpers.ts' />

src/services/codefixes/importFixes.ts

@@ -746,7 +746,7 @@ namespace ts.codefix {
         }
         else if (isJsxOpeningLikeElement(symbolToken.parent) && symbolToken.parent.tagName === symbolToken) {
             // The error wasn't for the symbolAtLocation, it was for the JSX tag itself, which needs access to e.g. `React`.
-            symbol = checker.getAliasedSymbol(checker.resolveName(checker.getJsxNamespace(), symbolToken.parent.tagName, SymbolFlags.Value));
+            symbol = checker.getAliasedSymbol(checker.resolveName(checker.getJsxNamespace(), symbolToken.parent.tagName, SymbolFlags.Value, /*excludeGlobals*/ false));
             symbolName = symbol.name;
         }
         else {
@@ -867,7 +867,7 @@ namespace ts.codefix {
         return moduleSpecifierToValidIdentifier(removeFileExtension(getBaseFileName(moduleSymbol.name)), target);
     }
 
-    function moduleSpecifierToValidIdentifier(moduleSpecifier: string, target: ScriptTarget): string {
+    export function moduleSpecifierToValidIdentifier(moduleSpecifier: string, target: ScriptTarget): string {
         let res = "";
         let lastCharWasValid = true;
         const firstCharCode = moduleSpecifier.charCodeAt(0);

src/services/formatting/rules.ts

@@ -11,8 +11,8 @@ namespace ts.formatting {
         for (let token = SyntaxKind.FirstToken; token <= SyntaxKind.LastToken; token++) {
             allTokens.push(token);
         }
-        function anyTokenExcept(token: SyntaxKind): TokenRange {
-            return { tokens: allTokens.filter(t => t !== token), isSpecific: false };
+        function anyTokenExcept(...tokens: SyntaxKind[]): TokenRange {
+            return { tokens: allTokens.filter(t => !tokens.some(t2 => t2 === t)), isSpecific: false };
         }
 
         const anyToken: TokenRange = { tokens: allTokens, isSpecific: false };
@@ -316,6 +316,11 @@ namespace ts.formatting {
 
             rule("NoSpaceBeforeComma", anyToken, SyntaxKind.CommaToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
 
+            // No space before and after indexer `x[]`
+            rule("NoSpaceBeforeOpenBracket", anyTokenExcept(SyntaxKind.AsyncKeyword, SyntaxKind.CaseKeyword), SyntaxKind.OpenBracketToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
+            rule("NoSpaceAfterCloseBracket", SyntaxKind.CloseBracketToken, anyToken, [isNonJsxSameLineTokenContext, isNotBeforeBlockInFunctionDeclarationContext], RuleAction.Delete),
+            rule("SpaceAfterSemicolon", SyntaxKind.SemicolonToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
+
             // Add a space between statements. All keywords except (do,else,case) has open/close parens after them.
             // So, we have a rule to add a space for [),Any], [do,Any], [else,Any], and [case,Any]
             rule(
@@ -326,11 +331,6 @@ namespace ts.formatting {
                 RuleAction.Space),
             // This low-pri rule takes care of "try {" and "finally {" in case the rule SpaceBeforeOpenBraceInControl didn't execute on FormatOnEnter.
             rule("SpaceAfterTryFinally", [SyntaxKind.TryKeyword, SyntaxKind.FinallyKeyword], SyntaxKind.OpenBraceToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
-
-            // No space before and after indexer `x[]`
-            rule("NoSpaceBeforeOpenBracket", anyTokenExcept(SyntaxKind.AsyncKeyword), SyntaxKind.OpenBracketToken, [isNonJsxSameLineTokenContext], RuleAction.Delete),
-            rule("NoSpaceAfterCloseBracket", SyntaxKind.CloseBracketToken, anyToken, [isNonJsxSameLineTokenContext, isNotBeforeBlockInFunctionDeclarationContext], RuleAction.Delete),
-            rule("SpaceAfterSemicolon", SyntaxKind.SemicolonToken, anyToken, [isNonJsxSameLineTokenContext], RuleAction.Space),
         ];
 
         return [

src/services/pathCompletions.ts

@@ -94,7 +94,7 @@ namespace ts.Completions.PathCompletions {
                  *
                  * both foo.ts and foo.tsx become foo
                  */
-                const foundFiles = createMap<boolean>();
+                const foundFiles = createMap<true>();
                 for (let filePath of files) {
                     filePath = normalizePath(filePath);
                     if (exclude && comparePaths(filePath, exclude, scriptPath, ignoreCase) === Comparison.EqualTo) {
@@ -103,7 +103,7 @@ namespace ts.Completions.PathCompletions {
 
                     const foundFileName = includeExtensions ? getBaseFileName(filePath) : removeFileExtension(getBaseFileName(filePath));
 
-                    if (!foundFiles.get(foundFileName)) {
+                    if (!foundFiles.has(foundFileName)) {
                         foundFiles.set(foundFileName, true);
                     }
                 }
@@ -226,8 +226,9 @@ namespace ts.Completions.PathCompletions {
         const includeGlob = normalizedSuffix ? "**/*" : "./*";
 
         const matches = tryReadDirectory(host, baseDirectory, fileExtensions, /*exclude*/ undefined, [includeGlob]);
+        const directories = tryGetDirectories(host, baseDirectory);
         // Trim away prefix and suffix
-        return mapDefined(matches, match => {
+        return mapDefined(concatenate(matches, directories), match => {
             const normalizedMatch = normalizePath(match);
             if (!endsWith(normalizedMatch, normalizedSuffix) || !startsWith(normalizedMatch, completePrefix)) {
                 return;
@@ -468,7 +469,7 @@ namespace ts.Completions.PathCompletions {
         return tryIOAndConsumeErrors(host, host.getDirectories, directoryName);
     }
 
-    function tryReadDirectory(host: LanguageServiceHost, path: string, extensions?: ReadonlyArray<string>, exclude?: ReadonlyArray<string>, include?: ReadonlyArray<string>): string[] {
+    function tryReadDirectory(host: LanguageServiceHost, path: string, extensions?: ReadonlyArray<string>, exclude?: ReadonlyArray<string>, include?: ReadonlyArray<string>): string[] | undefined {
         return tryIOAndConsumeErrors(host, host.readDirectory, path, extensions, exclude, include);
     }
 

src/services/refactors/convertToEs6Module.ts

@@ -0,0 +1,582 @@
+/* @internal */
+namespace ts.refactor {
+    const actionName = "Convert to ES6 module";
+
+    const convertToEs6Module: Refactor = {
+        name: actionName,
+        description: getLocaleSpecificMessage(Diagnostics.Convert_to_ES6_module),
+        getEditsForAction,
+        getAvailableActions,
+    };
+
+    registerRefactor(convertToEs6Module);
+
+    function getAvailableActions(context: RefactorContext): ApplicableRefactorInfo[] | undefined {
+        const { file, startPosition } = context;
+        if (!isSourceFileJavaScript(file) || !file.commonJsModuleIndicator) {
+            return undefined;
+        }
+
+        const node = getTokenAtPosition(file, startPosition, /*includeJsDocComment*/ false);
+        return !isAtTriggerLocation(file, node) ? undefined : [
+            {
+                name: convertToEs6Module.name,
+                description: convertToEs6Module.description,
+                actions: [
+                    {
+                        description: convertToEs6Module.description,
+                        name: actionName,
+                    },
+                ],
+            },
+        ];
+    }
+
+    function isAtTriggerLocation(sourceFile: SourceFile, node: Node, onSecondTry = false): boolean {
+        switch (node.kind) {
+            case SyntaxKind.CallExpression:
+                return isAtTopLevelRequire(node as CallExpression);
+            case SyntaxKind.PropertyAccessExpression:
+                return isExportsOrModuleExportsOrAlias(sourceFile, node as PropertyAccessExpression)
+                    || isExportsOrModuleExportsOrAlias(sourceFile, (node as PropertyAccessExpression).expression);
+            case SyntaxKind.VariableDeclarationList:
+                const decl = (node as VariableDeclarationList).declarations[0];
+                return isExportsOrModuleExportsOrAlias(sourceFile, decl.initializer);
+            case SyntaxKind.VariableDeclaration:
+                return isExportsOrModuleExportsOrAlias(sourceFile, (node as VariableDeclaration).initializer);
+            default:
+                return isExpression(node) && isExportsOrModuleExportsOrAlias(sourceFile, node)
+                    || !onSecondTry && isAtTriggerLocation(sourceFile, node.parent, /*onSecondTry*/ true);
+        }
+    }
+
+    function isAtTopLevelRequire(call: CallExpression): boolean {
+        if (!isRequireCall(call, /*checkArgumentIsStringLiteral*/ true)) {
+            return false;
+        }
+        const { parent: propAccess } = call;
+        const varDecl = isPropertyAccessExpression(propAccess) ? propAccess.parent : propAccess;
+        if (isExpressionStatement(varDecl) && isSourceFile(varDecl.parent)) { // `require("x");` as a statement
+            return true;
+        }
+        if (!isVariableDeclaration(varDecl)) {
+            return false;
+        }
+        const { parent: varDeclList } = varDecl;
+        if (varDeclList.kind !== SyntaxKind.VariableDeclarationList) {
+            return false;
+        }
+        const { parent: varStatement } = varDeclList;
+        return varStatement.kind === SyntaxKind.VariableStatement && varStatement.parent.kind === SyntaxKind.SourceFile;
+    }
+
+    function getEditsForAction(context: RefactorContext, _actionName: string): RefactorEditInfo | undefined {
+        Debug.assertEqual(actionName, _actionName);
+        const { file, program } = context;
+        Debug.assert(isSourceFileJavaScript(file));
+        const edits = textChanges.ChangeTracker.with(context, changes => {
+            const moduleExportsChangedToDefault = convertFileToEs6Module(file, program.getTypeChecker(), changes, program.getCompilerOptions().target);
+            if (moduleExportsChangedToDefault) {
+                for (const importingFile of program.getSourceFiles()) {
+                    fixImportOfModuleExports(importingFile, file, changes);
+                }
+            }
+        });
+        return { edits, renameFilename: undefined, renameLocation: undefined };
+    }
+
+    function fixImportOfModuleExports(importingFile: ts.SourceFile, exportingFile: ts.SourceFile, changes: textChanges.ChangeTracker) {
+        for (const moduleSpecifier of importingFile.imports) {
+            const imported = getResolvedModule(importingFile, moduleSpecifier.text);
+            if (!imported || imported.resolvedFileName !== exportingFile.fileName) {
+                continue;
+            }
+
+            const { parent } = moduleSpecifier;
+            switch (parent.kind) {
+                case SyntaxKind.ExternalModuleReference: {
+                    const importEq = (parent as ExternalModuleReference).parent;
+                    changes.replaceNode(importingFile, importEq, makeImport(importEq.name, /*namedImports*/ undefined, moduleSpecifier.text));
+                    break;
+                }
+                case SyntaxKind.CallExpression: {
+                    const call = parent as CallExpression;
+                    if (isRequireCall(call, /*checkArgumentIsStringLiteral*/ false)) {
+                        changes.replaceNode(importingFile, parent, createPropertyAccess(getSynthesizedDeepClone(call), "default"));
+                    }
+                    break;
+                }
+            }
+        }
+    }
+
+    /** @returns Whether we converted a `module.exports =` to a default export. */
+    function convertFileToEs6Module(sourceFile: SourceFile, checker: TypeChecker, changes: textChanges.ChangeTracker, target: ScriptTarget): ModuleExportsChanged {
+        const identifiers: Identifiers = { original: collectFreeIdentifiers(sourceFile), additional: createMap<true>() };
+        const exports = collectExportRenames(sourceFile, checker, identifiers);
+        convertExportsAccesses(sourceFile, exports, changes);
+        let moduleExportsChangedToDefault = false;
+        for (const statement of sourceFile.statements) {
+            const moduleExportsChanged = convertStatement(sourceFile, statement, checker, changes, identifiers, target, exports);
+            moduleExportsChangedToDefault = moduleExportsChangedToDefault || moduleExportsChanged;
+        }
+        return moduleExportsChangedToDefault;
+    }
+
+    /**
+     * Contains an entry for each renamed export.
+     * This is necessary because `exports.x = 0;` does not declare a local variable.
+     * Converting this to `export const x = 0;` would declare a local, so we must be careful to avoid shadowing.
+     * If there would be shadowing at either the declaration or at any reference to `exports.x` (now just `x`), we must convert to:
+     *     const _x = 0;
+     *     export { _x as x };
+     * This conversion also must place if the exported name is not a valid identifier, e.g. `exports.class = 0;`.
+     */
+    type ExportRenames = ReadonlyMap<string>;
+
+    function collectExportRenames(sourceFile: SourceFile, checker: TypeChecker, identifiers: Identifiers): ExportRenames {
+        const res = createMap<string>();
+        forEachExportReference(sourceFile, node => {
+            const { text, originalKeywordKind } = node.name;
+            if (!res.has(text) && (originalKeywordKind !== undefined && isNonContextualKeyword(originalKeywordKind)
+                || checker.resolveName(node.name.text, node, SymbolFlags.Value, /*excludeGlobals*/ true))) {
+                // Unconditionally add an underscore in case `text` is a keyword.
+                res.set(text, makeUniqueName(`_${text}`, identifiers));
+            }
+        });
+        return res;
+    }
+
+    function convertExportsAccesses(sourceFile: SourceFile, exports: ExportRenames, changes: textChanges.ChangeTracker): void {
+        forEachExportReference(sourceFile, (node, isAssignmentLhs) => {
+            if (isAssignmentLhs) {
+                return;
+            }
+            const { text } = node.name;
+            changes.replaceNode(sourceFile, node, createIdentifier(exports.get(text) || text));
+        });
+    }
+
+    function forEachExportReference(sourceFile: SourceFile, cb: (node: PropertyAccessExpression, isAssignmentLhs: boolean) => void): void {
+        sourceFile.forEachChild(function recur(node) {
+            if (isPropertyAccessExpression(node) && isExportsOrModuleExportsOrAlias(sourceFile, node.expression)) {
+                const { parent } = node;
+                cb(node, isBinaryExpression(parent) && parent.left === node && parent.operatorToken.kind === SyntaxKind.EqualsToken);
+            }
+            node.forEachChild(recur);
+        });
+    }
+
+    /** Whether `module.exports =` was changed to `export default` */
+    type ModuleExportsChanged = boolean;
+
+    function convertStatement(sourceFile: SourceFile, statement: Statement, checker: TypeChecker, changes: textChanges.ChangeTracker, identifiers: Identifiers, target: ScriptTarget, exports: ExportRenames): ModuleExportsChanged {
+        switch (statement.kind) {
+            case SyntaxKind.VariableStatement:
+                convertVariableStatement(sourceFile, statement as VariableStatement, changes, checker, identifiers, target);
+                return false;
+            case SyntaxKind.ExpressionStatement: {
+                const { expression } = statement as ExpressionStatement;
+                switch (expression.kind) {
+                    case SyntaxKind.CallExpression: {
+                        if (isRequireCall(expression, /*checkArgumentIsStringLiteral*/ true)) {
+                            // For side-effecting require() call, just make a side-effecting import.
+                            changes.replaceNode(sourceFile, statement, makeImport(/*name*/ undefined, /*namedImports*/ undefined, expression.arguments[0].text));
+                        }
+                        return false;
+                    }
+                    case SyntaxKind.BinaryExpression: {
+                        const { left, operatorToken, right } = expression as BinaryExpression;
+                        return operatorToken.kind === SyntaxKind.EqualsToken && convertAssignment(sourceFile, checker, statement as ExpressionStatement, left, right, changes, exports);
+                    }
+                }
+            }
+            // falls through
+            default:
+                return false;
+        }
+    }
+
+    function convertVariableStatement(sourceFile: SourceFile, statement: VariableStatement, changes: textChanges.ChangeTracker, checker: TypeChecker, identifiers: Identifiers, target: ScriptTarget): void {
+        const { declarationList } = statement as VariableStatement;
+        let foundImport = false;
+        const newNodes = flatMap(declarationList.declarations, decl => {
+            const { name, initializer } = decl;
+            if (isExportsOrModuleExportsOrAlias(sourceFile, initializer)) {
+                // `const alias = module.exports;` can be removed.
+                foundImport = true;
+                return [];
+            }
+            if (isRequireCall(initializer, /*checkArgumentIsStringLiteral*/ true)) {
+                foundImport = true;
+                return convertSingleImport(sourceFile, name, initializer.arguments[0].text, changes, checker, identifiers, target);
+            }
+            else if (isPropertyAccessExpression(initializer) && isRequireCall(initializer.expression, /*checkArgumentIsStringLiteral*/ true)) {
+                foundImport = true;
+                return convertPropertyAccessImport(name, initializer.name.text, initializer.expression.arguments[0].text, identifiers);
+            }
+            else {
+                // Move it out to its own variable statement.
+                return createVariableStatement(/*modifiers*/ undefined, createVariableDeclarationList([decl], declarationList.flags));
+            }
+        });
+        if (foundImport) {
+            // useNonAdjustedEndPosition to ensure we don't eat the newline after the statement.
+            changes.replaceNodeWithNodes(sourceFile, statement, newNodes);
+        }
+    }
+
+    /** Converts `const name = require("moduleSpecifier").propertyName` */
+    function convertPropertyAccessImport(name: BindingName, propertyName: string, moduleSpecifier: string, identifiers: Identifiers): ReadonlyArray<Node> {
+        switch (name.kind) {
+            case SyntaxKind.ObjectBindingPattern:
+            case SyntaxKind.ArrayBindingPattern: {
+                // `const [a, b] = require("c").d` --> `import { d } from "c"; const [a, b] = d;`
+                const tmp  = makeUniqueName(propertyName, identifiers);
+                return [
+                    makeSingleImport(tmp, propertyName, moduleSpecifier),
+                    makeConst(/*modifiers*/ undefined, name, createIdentifier(tmp)),
+                ];
+            }
+            case SyntaxKind.Identifier:
+                // `const a = require("b").c` --> `import { c as a } from "./b";
+                return [makeSingleImport(name.text, propertyName, moduleSpecifier)];
+            default:
+                Debug.assertNever(name);
+        }
+    }
+
+    function convertAssignment(
+        sourceFile: SourceFile,
+        checker: TypeChecker,
+        statement: ExpressionStatement,
+        left: Expression,
+        right: Expression,
+        changes: textChanges.ChangeTracker,
+        exports: ExportRenames,
+    ): ModuleExportsChanged {
+        if (!isPropertyAccessExpression(left)) {
+            return false;
+        }
+
+        if (isExportsOrModuleExportsOrAlias(sourceFile, left)) {
+            if (isExportsOrModuleExportsOrAlias(sourceFile, right)) {
+                // `const alias = module.exports;` or `module.exports = alias;` can be removed.
+                changes.deleteNode(sourceFile, statement);
+            }
+            else {
+                let newNodes = isObjectLiteralExpression(right) ? tryChangeModuleExportsObject(right) : undefined;
+                let changedToDefaultExport = false;
+                if (!newNodes) {
+                    ([newNodes, changedToDefaultExport] = convertModuleExportsToExportDefault(right, checker));
+                }
+                changes.replaceNodeWithNodes(sourceFile, statement, newNodes);
+                return changedToDefaultExport;
+            }
+        }
+        else if (isExportsOrModuleExportsOrAlias(sourceFile, left.expression)) {
+            convertNamedExport(sourceFile, statement, left.name, right, changes, exports);
+        }
+
+        return false;
+    }
+
+    /**
+     * Convert `module.exports = { ... }` to individual exports..
+     * We can't always do this if the module has interesting members -- then it will be a default export instead.
+     */
+    function tryChangeModuleExportsObject(object: ObjectLiteralExpression): ReadonlyArray<Statement> | undefined {
+        return mapAllOrFail(object.properties, prop => {
+            switch (prop.kind) {
+                case SyntaxKind.GetAccessor:
+                case SyntaxKind.SetAccessor:
+                // TODO: Maybe we should handle this? See fourslash test `refactorConvertToEs6Module_export_object_shorthand.ts`.
+                case SyntaxKind.ShorthandPropertyAssignment:
+                case SyntaxKind.SpreadAssignment:
+                    return undefined;
+                case SyntaxKind.PropertyAssignment: {
+                    const { name, initializer } = prop as PropertyAssignment;
+                    return !isIdentifier(name) ? undefined : convertExportsDotXEquals(name.text, initializer);
+                }
+                case SyntaxKind.MethodDeclaration: {
+                    const m = prop as MethodDeclaration;
+                    return !isIdentifier(m.name) ? undefined : functionExpressionToDeclaration(m.name.text, [createToken(SyntaxKind.ExportKeyword)], m);
+                }
+                default:
+                    Debug.assertNever(prop);
+            }
+        });
+    }
+
+    function convertNamedExport(
+        sourceFile: SourceFile,
+        statement: Statement,
+        propertyName: Identifier,
+        right: Expression,
+        changes: textChanges.ChangeTracker,
+        exports: ExportRenames,
+    ): void {
+        // If "originalKeywordKind" was set, this is e.g. `exports.
+        const { text } = propertyName;
+        const rename = exports.get(text);
+        if (rename !== undefined) {
+            /*
+            const _class = 0;
+            export { _class as class };
+            */
+            const newNodes = [
+                makeConst(/*modifiers*/ undefined, rename, right),
+                makeExportDeclaration([createExportSpecifier(rename, text)]),
+            ];
+            changes.replaceNodeWithNodes(sourceFile, statement, newNodes);
+        }
+        else {
+            changes.replaceNode(sourceFile, statement, convertExportsDotXEquals(text, right), { useNonAdjustedEndPosition: true });
+        }
+    }
+
+    function convertModuleExportsToExportDefault(exported: Expression, checker: TypeChecker): [ReadonlyArray<Statement>, ModuleExportsChanged] {
+        const modifiers = [createToken(SyntaxKind.ExportKeyword), createToken(SyntaxKind.DefaultKeyword)];
+        switch (exported.kind) {
+            case SyntaxKind.FunctionExpression:
+            case SyntaxKind.ArrowFunction: {
+                // `module.exports = function f() {}` --> `export default function f() {}`
+                const fn = exported as FunctionExpression | ArrowFunction;
+                return [[functionExpressionToDeclaration(fn.name && fn.name.text, modifiers, fn)], true];
+            }
+            case SyntaxKind.ClassExpression: {
+                // `module.exports = class C {}` --> `export default class C {}`
+                const cls = exported as ClassExpression;
+                return [[classExpressionToDeclaration(cls.name && cls.name.text, modifiers, cls)], true];
+            }
+            case SyntaxKind.CallExpression:
+                if (isRequireCall(exported, /*checkArgumentIsStringLiteral*/ true)) {
+                    return convertReExportAll(exported.arguments[0], checker);
+                }
+                // falls through
+            default:
+                // `module.exports = 0;` --> `export default 0;`
+                return [[createExportAssignment(/*decorators*/ undefined, /*modifiers*/ undefined, /*isExportEquals*/ false, exported)], true];
+        }
+    }
+
+    function convertReExportAll(reExported: StringLiteralLike, checker: TypeChecker): [ReadonlyArray<Statement>, ModuleExportsChanged] {
+        // `module.exports = require("x");` ==> `export * from "x"; export { default } from "x";`
+        const moduleSpecifier = reExported.text;
+        const moduleSymbol = checker.getSymbolAtLocation(reExported);
+        const exports = moduleSymbol ? moduleSymbol.exports : emptyUnderscoreEscapedMap;
+        return exports.has("export=" as __String)
+            ? [[reExportDefault(moduleSpecifier)], true]
+            : !exports.has("default" as __String)
+            ? [[reExportStar(moduleSpecifier)], false]
+            // If there's some non-default export, must include both `export *` and `export default`.
+            : exports.size > 1 ? [[reExportStar(moduleSpecifier), reExportDefault(moduleSpecifier)], true] : [[reExportDefault(moduleSpecifier)], true];
+    }
+    function reExportStar(moduleSpecifier: string): ExportDeclaration {
+        return makeExportDeclaration(/*exportClause*/ undefined, moduleSpecifier);
+    }
+    function reExportDefault(moduleSpecifier: string): ExportDeclaration {
+        return makeExportDeclaration([createExportSpecifier(/*propertyName*/ undefined, "default")], moduleSpecifier);
+    }
+
+    function convertExportsDotXEquals(name: string | undefined, exported: Expression): Statement {
+        const modifiers = [createToken(SyntaxKind.ExportKeyword)];
+        switch (exported.kind) {
+            case SyntaxKind.FunctionExpression:
+            case SyntaxKind.ArrowFunction:
+                // `exports.f = function() {}` --> `export function f() {}`
+                return functionExpressionToDeclaration(name, modifiers, exported as FunctionExpression | ArrowFunction);
+            case SyntaxKind.ClassExpression:
+                // `exports.C = class {}` --> `export class C {}`
+                return classExpressionToDeclaration(name, modifiers, exported as ClassExpression);
+            default:
+                // `exports.x = 0;` --> `export const x = 0;`
+                return makeConst(modifiers, createIdentifier(name), exported);
+        }
+    }
+
+    /**
+     * Converts `const <<name>> = require("x");`.
+     * Returns nodes that will replace the variable declaration for the commonjs import.
+     * May also make use `changes` to remove qualifiers at the use sites of imports, to change `mod.x` to `x`.
+     */
+    function convertSingleImport(
+        file: SourceFile,
+        name: BindingName,
+        moduleSpecifier: string,
+        changes: textChanges.ChangeTracker,
+        checker: TypeChecker,
+        identifiers: Identifiers,
+        target: ScriptTarget,
+    ): ReadonlyArray<Node> {
+        switch (name.kind) {
+            case SyntaxKind.ObjectBindingPattern: {
+                const importSpecifiers = mapAllOrFail(name.elements, e =>
+                    e.dotDotDotToken || e.initializer || e.propertyName && !isIdentifier(e.propertyName) || !isIdentifier(e.name)
+                        ? undefined
+                        : makeImportSpecifier(e.propertyName && (e.propertyName as Identifier).text, e.name.text));
+                if (importSpecifiers) {
+                    return [makeImport(/*name*/ undefined, importSpecifiers, moduleSpecifier)];
+                }
+            }
+            // falls through -- object destructuring has an interesting pattern and must be a variable declaration
+            case SyntaxKind.ArrayBindingPattern: {
+                /*
+                import x from "x";
+                const [a, b, c] = x;
+                */
+                const tmp = makeUniqueName(codefix.moduleSpecifierToValidIdentifier(moduleSpecifier, target), identifiers);
+                return [
+                    makeImport(createIdentifier(tmp), /*namedImports*/ undefined, moduleSpecifier),
+                    makeConst(/*modifiers*/ undefined, getSynthesizedDeepClone(name), createIdentifier(tmp)),
+                ];
+            }
+            case SyntaxKind.Identifier:
+                return convertSingleIdentifierImport(file, name, moduleSpecifier, changes, checker, identifiers);
+            default:
+                Debug.assertNever(name);
+        }
+    }
+
+    /**
+     * Convert `import x = require("x").`
+     * Also converts uses like `x.y()` to `y()` and uses a named import.
+     */
+    function convertSingleIdentifierImport(file: SourceFile, name: Identifier, moduleSpecifier: string, changes: textChanges.ChangeTracker, checker: TypeChecker, identifiers: Identifiers): ReadonlyArray<Node> {
+        const nameSymbol = checker.getSymbolAtLocation(name);
+        // Maps from module property name to name actually used. (The same if there isn't shadowing.)
+        const namedBindingsNames = createMap<string>();
+        // True if there is some non-property use like `x()` or `f(x)`.
+        let needDefaultImport = false;
+
+        for (const use of identifiers.original.get(name.text)) {
+            if (checker.getSymbolAtLocation(use) !== nameSymbol || use === name) {
+                // This was a use of a different symbol with the same name, due to shadowing. Ignore.
+                continue;
+            }
+
+            const { parent } = use;
+            if (isPropertyAccessExpression(parent)) {
+                const { expression, name: { text: propertyName } } = parent;
+                Debug.assert(expression === use); // Else shouldn't have been in `collectIdentifiers`
+                let idName = namedBindingsNames.get(propertyName);
+                if (idName === undefined) {
+                    idName = makeUniqueName(propertyName, identifiers);
+                    namedBindingsNames.set(propertyName, idName);
+                }
+                changes.replaceNode(file, parent, createIdentifier(idName));
+            }
+            else {
+                needDefaultImport = true;
+            }
+        }
+
+        const namedBindings = namedBindingsNames.size === 0 ? undefined : arrayFrom(mapIterator(namedBindingsNames.entries(), ([propertyName, idName]) =>
+            createImportSpecifier(propertyName === idName ? undefined : createIdentifier(propertyName), createIdentifier(idName))));
+        if (!namedBindings) {
+            // If it was unused, ensure that we at least import *something*.
+            needDefaultImport = true;
+        }
+        return [makeImport(needDefaultImport ? getSynthesizedDeepClone(name) : undefined, namedBindings, moduleSpecifier)];
+    }
+
+    // Identifiers helpers
+
+    function makeUniqueName(name: string, identifiers: Identifiers): string {
+        while (identifiers.original.has(name) || identifiers.additional.has(name)) {
+            name = `_${name}`;
+        }
+        identifiers.additional.set(name, true);
+        return name;
+    }
+
+    /**
+     * Helps us create unique identifiers.
+     * `original` refers to the local variable names in the original source file.
+     * `additional` is any new unique identifiers we've generated. (e.g., we'll generate `_x`, then `__x`.)
+     */
+    interface Identifiers {
+        readonly original: FreeIdentifiers;
+        // Additional identifiers we've added. Mutable!
+        readonly additional: Map<true>;
+    }
+
+    type FreeIdentifiers = ReadonlyMap<ReadonlyArray<Identifier>>;
+    function collectFreeIdentifiers(file: SourceFile): FreeIdentifiers {
+        const map = createMultiMap<Identifier>();
+        file.forEachChild(function recur(node) {
+            if (isIdentifier(node) && isFreeIdentifier(node)) {
+                map.add(node.text, node);
+            }
+            node.forEachChild(recur);
+        });
+        return map;
+    }
+
+    function isFreeIdentifier(node: Identifier): boolean {
+        const { parent } = node;
+        switch (parent.kind) {
+            case SyntaxKind.PropertyAccessExpression:
+                return (parent as PropertyAccessExpression).name !== node;
+            case SyntaxKind.BindingElement:
+                return (parent as BindingElement).propertyName !== node;
+            default:
+                return true;
+        }
+    }
+
+    // Node helpers
+
+    function functionExpressionToDeclaration(name: string | undefined, additionalModifiers: ReadonlyArray<Modifier>, fn: FunctionExpression | ArrowFunction | MethodDeclaration): FunctionDeclaration {
+        return createFunctionDeclaration(
+            getSynthesizedDeepClones(fn.decorators), // TODO: GH#19915 Don't think this is even legal.
+            concatenate(additionalModifiers, getSynthesizedDeepClones(fn.modifiers)),
+            getSynthesizedDeepClone(fn.asteriskToken),
+            name,
+            getSynthesizedDeepClones(fn.typeParameters),
+            getSynthesizedDeepClones(fn.parameters),
+            getSynthesizedDeepClone(fn.type),
+            convertToFunctionBody(getSynthesizedDeepClone(fn.body)));
+    }
+
+    function classExpressionToDeclaration(name: string | undefined, additionalModifiers: ReadonlyArray<Modifier>, cls: ClassExpression): ClassDeclaration {
+        return createClassDeclaration(
+            getSynthesizedDeepClones(cls.decorators), // TODO: GH#19915 Don't think this is even legal.
+            concatenate(additionalModifiers, getSynthesizedDeepClones(cls.modifiers)),
+            name,
+            getSynthesizedDeepClones(cls.typeParameters),
+            getSynthesizedDeepClones(cls.heritageClauses),
+            getSynthesizedDeepClones(cls.members));
+    }
+
+    function makeSingleImport(localName: string, propertyName: string, moduleSpecifier: string): ImportDeclaration {
+        return propertyName === "default"
+            ? makeImport(createIdentifier(localName), /*namedImports*/ undefined, moduleSpecifier)
+            : makeImport(/*name*/ undefined, [makeImportSpecifier(propertyName, localName)], moduleSpecifier);
+    }
+
+    function makeImport(name: Identifier | undefined, namedImports: ReadonlyArray<ImportSpecifier>, moduleSpecifier: string): ImportDeclaration {
+        const importClause = (name || namedImports) && createImportClause(name, namedImports && createNamedImports(namedImports));
+        return createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, importClause, createLiteral(moduleSpecifier));
+    }
+
+    function makeImportSpecifier(propertyName: string | undefined, name: string): ImportSpecifier {
+        return createImportSpecifier(propertyName !== undefined && propertyName !== name ? createIdentifier(propertyName) : undefined, createIdentifier(name));
+    }
+
+    function makeConst(modifiers: ReadonlyArray<Modifier> | undefined, name: string | BindingName, init: Expression): VariableStatement {
+        return createVariableStatement(
+            modifiers,
+            createVariableDeclarationList(
+                [createVariableDeclaration(name, /*type*/ undefined, init)],
+                NodeFlags.Const));
+    }
+
+    function makeExportDeclaration(exportSpecifiers: ExportSpecifier[] | undefined, moduleSpecifier?: string): ExportDeclaration {
+        return createExportDeclaration(
+            /*decorators*/ undefined,
+            /*modifiers*/ undefined,
+            exportSpecifiers && createNamedExports(exportSpecifiers),
+            moduleSpecifier === undefined ? undefined : createLiteral(moduleSpecifier));
+    }
+}

src/services/refactors/extractSymbol.ts

@@ -1692,7 +1692,7 @@ namespace ts.refactor.extractSymbol {
             }
             for (let i = 0; i < scopes.length; i++) {
                 const scope = scopes[i];
-                const resolvedSymbol = checker.resolveName(symbol.name, scope, symbol.flags);
+                const resolvedSymbol = checker.resolveName(symbol.name, scope, symbol.flags, /*excludeGlobals*/ false);
                 if (resolvedSymbol === symbol) {
                     continue;
                 }

src/services/refactors/refactors.ts

@@ -1,5 +1,6 @@
 /// <reference path="annotateWithTypeFromJSDoc.ts" />
 /// <reference path="convertFunctionToEs6Class.ts" />
+/// <reference path="convertToEs6Module.ts" />
 /// <reference path="extractSymbol.ts" />
 /// <reference path="installTypesForPackage.ts" />
 /// <reference path="useDefaultImport.ts" />

src/services/refactors/useDefaultImport.ts

@@ -23,7 +23,7 @@ namespace ts.refactor.installTypesForPackage {
             return undefined;
         }
 
-        const module = ts.getResolvedModule(file, importInfo.moduleSpecifier.text);
+        const module = getResolvedModule(file, importInfo.moduleSpecifier.text);
         const resolvedFile = program.getSourceFile(module.resolvedFileName);
         if (!(resolvedFile.externalModuleIndicator && isExportAssignment(resolvedFile.externalModuleIndicator) && resolvedFile.externalModuleIndicator.isExportEquals)) {
             return undefined;
@@ -52,7 +52,7 @@ namespace ts.refactor.installTypesForPackage {
         }
         const { importStatement, name, moduleSpecifier } = importInfo;
         const newImportClause = createImportClause(name, /*namedBindings*/ undefined);
-        const newImportStatement = ts.createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, newImportClause, moduleSpecifier);
+        const newImportStatement = createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, newImportClause, moduleSpecifier);
         return {
             edits: textChanges.ChangeTracker.with(context, t => t.replaceNode(file, importStatement, newImportStatement)),
             renameFilename: undefined,

src/services/textChanges.ts

@@ -345,6 +345,11 @@ namespace ts.textChanges {
             return this.replaceWithSingle(sourceFile, startPosition, startPosition, newNode, this.getOptionsForInsertNodeBefore(before, blankLineBetween));
         }
 
+        public insertModifierBefore(sourceFile: SourceFile, modifier: SyntaxKind, before: Node): void {
+            const pos = before.getStart(sourceFile);
+            this.replaceWithSingle(sourceFile, pos, pos, createToken(modifier), { suffix: " " });
+        }
+
         public changeIdentifierToPropertyAccess(sourceFile: SourceFile, prefix: string, node: Identifier): void {
             const startPosition = getAdjustedStartPosition(sourceFile, node, {}, Position.Start);
             this.replaceWithSingle(sourceFile, startPosition, startPosition, createPropertyAccess(createIdentifier(prefix), ""), {});

src/services/utilities.ts

@@ -1354,6 +1354,10 @@ namespace ts {
         return visited;
     }
 
+    export function getSynthesizedDeepClones<T extends Node>(nodes: NodeArray<T> | undefined): NodeArray<T> | undefined {
+        return nodes && createNodeArray(nodes.map(getSynthesizedDeepClone), nodes.hasTrailingComma);
+    }
+
     /**
      * Sets EmitFlags to suppress leading and trailing trivia on the node.
      */

tests/baselines/reference/abstractPropertyNegative.errors.txt

@@ -7,11 +7,11 @@ tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstra
 tests/cases/compiler/abstractPropertyNegative.ts(15,5): error TS1244: Abstract methods can only appear within an abstract class.
 tests/cases/compiler/abstractPropertyNegative.ts(16,37): error TS1005: '{' expected.
 tests/cases/compiler/abstractPropertyNegative.ts(19,3): error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
-tests/cases/compiler/abstractPropertyNegative.ts(25,5): error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(25,5): error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'WrongTypeProperty'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/abstractPropertyNegative.ts(31,9): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(31,9): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'WrongTypeAccessor'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/abstractPropertyNegative.ts(34,5): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(34,5): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'WrongTypeAccessor'.
   Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/abstractPropertyNegative.ts(38,18): error TS2676: Accessors must both be abstract or non-abstract.
 tests/cases/compiler/abstractPropertyNegative.ts(39,9): error TS2676: Accessors must both be abstract or non-abstract.
@@ -64,7 +64,7 @@ tests/cases/compiler/abstractPropertyNegative.ts(41,18): error TS2676: Accessors
     class WrongTypePropertyImpl extends WrongTypeProperty {
         num = "nope, wrong";
         ~~~
-!!! error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'WrongTypeProperty'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     abstract class WrongTypeAccessor {
@@ -73,13 +73,13 @@ tests/cases/compiler/abstractPropertyNegative.ts(41,18): error TS2676: Accessors
     class WrongTypeAccessorImpl extends WrongTypeAccessor {
         get num() { return "nope, wrong"; }
             ~~~
-!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'WrongTypeAccessor'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     class WrongTypeAccessorImpl2 extends WrongTypeAccessor {
         num = "nope, wrong";
         ~~~
-!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'WrongTypeAccessor'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     

tests/baselines/reference/anyMappedTypesError.errors.txt

@@ -0,0 +1,7 @@
+tests/cases/compiler/anyMappedTypesError.ts(1,12): error TS7039: Mapped object type implicitly has an 'any' template type.
+
+
+==== tests/cases/compiler/anyMappedTypesError.ts (1 errors) ====
+    type Foo = {[P in "bar"]};
+               ~~~~~~~~~~~~~~
+!!! error TS7039: Mapped object type implicitly has an 'any' template type.

tests/baselines/reference/anyMappedTypesError.js

@@ -0,0 +1,4 @@
+//// [anyMappedTypesError.ts]
+type Foo = {[P in "bar"]};
+
+//// [anyMappedTypesError.js]

tests/baselines/reference/anyMappedTypesError.symbols

@@ -0,0 +1,5 @@
+=== tests/cases/compiler/anyMappedTypesError.ts ===
+type Foo = {[P in "bar"]};
+>Foo : Symbol(Foo, Decl(anyMappedTypesError.ts, 0, 0))
+>P : Symbol(P, Decl(anyMappedTypesError.ts, 0, 13))
+

tests/baselines/reference/anyMappedTypesError.types

@@ -0,0 +1,5 @@
+=== tests/cases/compiler/anyMappedTypesError.ts ===
+type Foo = {[P in "bar"]};
+>Foo : Foo
+>P : P
+

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -901,6 +901,7 @@ declare namespace ts {
         kind: SyntaxKind.ArrowFunction;
         equalsGreaterThanToken: EqualsGreaterThanToken;
         body: ConciseBody;
+        name: never;
     }
     interface LiteralLikeNode extends Node {
         text: string;
@@ -1362,6 +1363,7 @@ declare namespace ts {
     interface ExportDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ExportDeclaration;
         parent?: SourceFile | ModuleBlock;
+        /** Will not be assigned in the case of `export * from "foo";` */
         exportClause?: NamedExports;
         /** If this is not a StringLiteral it will be a grammar error. */
         moduleSpecifier?: Expression;
@@ -3288,7 +3290,7 @@ declare namespace ts {
 declare namespace ts {
     function createNodeArray<T extends Node>(elements?: ReadonlyArray<T>, hasTrailingComma?: boolean): NodeArray<T>;
     /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
-    function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
+    function createLiteral(value: string | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: number): NumericLiteral;
     function createLiteral(value: boolean): BooleanLiteral;
     function createLiteral(value: string | number | boolean): PrimaryExpression;

tests/baselines/reference/api/typescript.d.ts

@@ -901,6 +901,7 @@ declare namespace ts {
         kind: SyntaxKind.ArrowFunction;
         equalsGreaterThanToken: EqualsGreaterThanToken;
         body: ConciseBody;
+        name: never;
     }
     interface LiteralLikeNode extends Node {
         text: string;
@@ -1362,6 +1363,7 @@ declare namespace ts {
     interface ExportDeclaration extends DeclarationStatement {
         kind: SyntaxKind.ExportDeclaration;
         parent?: SourceFile | ModuleBlock;
+        /** Will not be assigned in the case of `export * from "foo";` */
         exportClause?: NamedExports;
         /** If this is not a StringLiteral it will be a grammar error. */
         moduleSpecifier?: Expression;
@@ -3235,7 +3237,7 @@ declare namespace ts {
 declare namespace ts {
     function createNodeArray<T extends Node>(elements?: ReadonlyArray<T>, hasTrailingComma?: boolean): NodeArray<T>;
     /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
-    function createLiteral(value: string | StringLiteral | NumericLiteral | Identifier): StringLiteral;
+    function createLiteral(value: string | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier): StringLiteral;
     function createLiteral(value: number): NumericLiteral;
     function createLiteral(value: boolean): BooleanLiteral;
     function createLiteral(value: string | number | boolean): PrimaryExpression;

tests/baselines/reference/apparentTypeSubtyping.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'Base<string>'.
   Type 'String' is not assignable to type 'string'.
     'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
 
@@ -15,7 +15,7 @@ tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtypi
     class Derived<U> extends Base<string> { // error
         x: String;
         ~
-!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'Base<string>'.
 !!! error TS2416:   Type 'String' is not assignable to type 'string'.
 !!! error TS2416:     'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
     }

tests/baselines/reference/apparentTypeSupertype.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSupertype.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSupertype.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'Base'.
   Type 'U' is not assignable to type 'string'.
     Type 'String' is not assignable to type 'string'.
       'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
@@ -16,7 +16,7 @@ tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSuperty
     class Derived<U extends String> extends Base { // error
         x: U;
         ~
-!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type 'U' is not assignable to type 'string'.
 !!! error TS2416:     Type 'String' is not assignable to type 'string'.
 !!! error TS2416:       'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.

tests/baselines/reference/baseClassImprovedMismatchErrors.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/baseClassImprovedMismatchErrors.ts(8,5): error TS2416: Property 'n' in type 'Derived' is not assignable to the same property in base type 'string | Base'.
+tests/cases/compiler/baseClassImprovedMismatchErrors.ts(8,5): error TS2416: Property 'n' in type 'Derived' is not assignable to the same property in base type 'Base'.
   Type 'string | Derived' is not assignable to type 'string | Base'.
     Type 'Derived' is not assignable to type 'string | Base'.
       Type 'Derived' is not assignable to type 'Base'.
@@ -6,11 +6,11 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(8,5): error TS2416: Prop
           Type 'string | Derived' is not assignable to type 'string | Base'.
             Type 'Derived' is not assignable to type 'string | Base'.
               Type 'Derived' is not assignable to type 'Base'.
-tests/cases/compiler/baseClassImprovedMismatchErrors.ts(9,5): error TS2416: Property 'fn' in type 'Derived' is not assignable to the same property in base type '() => number'.
+tests/cases/compiler/baseClassImprovedMismatchErrors.ts(9,5): error TS2416: Property 'fn' in type 'Derived' is not assignable to the same property in base type 'Base'.
   Type '() => string | number' is not assignable to type '() => number'.
     Type 'string | number' is not assignable to type 'number'.
       Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/baseClassImprovedMismatchErrors.ts(14,5): error TS2416: Property 'n' in type 'DerivedInterface' is not assignable to the same property in base type 'string | Base'.
+tests/cases/compiler/baseClassImprovedMismatchErrors.ts(14,5): error TS2416: Property 'n' in type 'DerivedInterface' is not assignable to the same property in base type 'Base'.
   Type 'string | DerivedInterface' is not assignable to type 'string | Base'.
     Type 'DerivedInterface' is not assignable to type 'string | Base'.
       Type 'DerivedInterface' is not assignable to type 'Base'.
@@ -18,7 +18,7 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(14,5): error TS2416: Pro
           Type 'string | DerivedInterface' is not assignable to type 'string | Base'.
             Type 'DerivedInterface' is not assignable to type 'string | Base'.
               Type 'DerivedInterface' is not assignable to type 'Base'.
-tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Property 'fn' in type 'DerivedInterface' is not assignable to the same property in base type '() => number'.
+tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Property 'fn' in type 'DerivedInterface' is not assignable to the same property in base type 'Base'.
   Type '() => string | number' is not assignable to type '() => number'.
     Type 'string | number' is not assignable to type 'number'.
       Type 'string' is not assignable to type 'number'.
@@ -34,7 +34,7 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Pro
     class Derived extends Base {
         n: Derived | string;
         ~
-!!! error TS2416: Property 'n' in type 'Derived' is not assignable to the same property in base type 'string | Base'.
+!!! error TS2416: Property 'n' in type 'Derived' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type 'string | Derived' is not assignable to type 'string | Base'.
 !!! error TS2416:     Type 'Derived' is not assignable to type 'string | Base'.
 !!! error TS2416:       Type 'Derived' is not assignable to type 'Base'.
@@ -44,7 +44,7 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Pro
 !!! error TS2416:               Type 'Derived' is not assignable to type 'Base'.
         fn() {
         ~~
-!!! error TS2416: Property 'fn' in type 'Derived' is not assignable to the same property in base type '() => number'.
+!!! error TS2416: Property 'fn' in type 'Derived' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type '() => string | number' is not assignable to type '() => number'.
 !!! error TS2416:     Type 'string | number' is not assignable to type 'number'.
 !!! error TS2416:       Type 'string' is not assignable to type 'number'.
@@ -54,7 +54,7 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Pro
     class DerivedInterface implements Base {
         n: DerivedInterface | string;
         ~
-!!! error TS2416: Property 'n' in type 'DerivedInterface' is not assignable to the same property in base type 'string | Base'.
+!!! error TS2416: Property 'n' in type 'DerivedInterface' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type 'string | DerivedInterface' is not assignable to type 'string | Base'.
 !!! error TS2416:     Type 'DerivedInterface' is not assignable to type 'string | Base'.
 !!! error TS2416:       Type 'DerivedInterface' is not assignable to type 'Base'.
@@ -64,7 +64,7 @@ tests/cases/compiler/baseClassImprovedMismatchErrors.ts(15,5): error TS2416: Pro
 !!! error TS2416:               Type 'DerivedInterface' is not assignable to type 'Base'.
         fn() {
         ~~
-!!! error TS2416: Property 'fn' in type 'DerivedInterface' is not assignable to the same property in base type '() => number'.
+!!! error TS2416: Property 'fn' in type 'DerivedInterface' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type '() => string | number' is not assignable to type '() => number'.
 !!! error TS2416:     Type 'string | number' is not assignable to type 'number'.
 !!! error TS2416:       Type 'string' is not assignable to type 'number'.

tests/baselines/reference/classIsSubtypeOfBaseType.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classIsSubtypeOfBaseType.ts(12,5): error TS2416: Property 'foo' in type 'Derived2' is not assignable to the same property in base type '{ bar: string; }'.
+tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/classIsSubtypeOfBaseType.ts(12,5): error TS2416: Property 'foo' in type 'Derived2' is not assignable to the same property in base type 'Base<{ bar: string; }>'.
   Type '{ bar?: string; }' is not assignable to type '{ bar: string; }'.
     Property 'bar' is optional in type '{ bar?: string; }' but required in type '{ bar: string; }'.
 
@@ -17,7 +17,7 @@ tests/cases/conformance/classes/classDeclarations/classHeritageSpecification/cla
     class Derived2 extends Base<{ bar: string; }> {
         foo: {
         ~~~
-!!! error TS2416: Property 'foo' in type 'Derived2' is not assignable to the same property in base type '{ bar: string; }'.
+!!! error TS2416: Property 'foo' in type 'Derived2' is not assignable to the same property in base type 'Base<{ bar: string; }>'.
 !!! error TS2416:   Type '{ bar?: string; }' is not assignable to type '{ bar: string; }'.
 !!! error TS2416:     Property 'bar' is optional in type '{ bar?: string; }' but required in type '{ bar: string; }'.
             bar?: string; // error

tests/baselines/reference/derivedClassFunctionOverridesBaseClassAccessor.errors.txt

@@ -1,6 +1,6 @@
 tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFunctionOverridesBaseClassAccessor.ts(2,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFunctionOverridesBaseClassAccessor.ts(5,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
-tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFunctionOverridesBaseClassAccessor.ts(11,5): error TS2416: Property 'x' in type 'Derived' is not assignable to the same property in base type 'number'.
+tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFunctionOverridesBaseClassAccessor.ts(11,5): error TS2416: Property 'x' in type 'Derived' is not assignable to the same property in base type 'Base'.
   Type '() => number' is not assignable to type 'number'.
 tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFunctionOverridesBaseClassAccessor.ts(11,5): error TS2426: Class 'Base' defines instance member accessor 'x', but extended class 'Derived' defines it as instance member function.
 
@@ -22,7 +22,7 @@ tests/cases/conformance/classes/members/inheritanceAndOverriding/derivedClassFun
     class Derived extends Base {
         x() {
         ~
-!!! error TS2416: Property 'x' in type 'Derived' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'x' in type 'Derived' is not assignable to the same property in base type 'Base'.
 !!! error TS2416:   Type '() => number' is not assignable to type 'number'.
         ~
 !!! error TS2426: Class 'Base' defines instance member accessor 'x', but extended class 'Derived' defines it as instance member function.

tests/baselines/reference/destructuringParameterDeclaration2.errors.txt

@@ -35,7 +35,7 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(46,13): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(47,13): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(56,8): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
-tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(57,5): error TS2416: Property 'd4' in type 'C4' is not assignable to the same property in base type '({ x, y, z }?: { x: any; y: any; z: any; }) => any'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(57,5): error TS2416: Property 'd4' in type 'C4' is not assignable to the same property in base type 'F2'.
   Type '({ x, y, c }: { x: any; y: any; c: any; }) => void' is not assignable to type '({ x, y, z }?: { x: any; y: any; z: any; }) => any'.
     Types of parameters '__0' and '__0' are incompatible.
       Type '{ x: any; y: any; z: any; }' is not assignable to type '{ x: any; y: any; c: any; }'.
@@ -159,7 +159,7 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
 !!! error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
         d4({x, y, c}) { }
         ~~
-!!! error TS2416: Property 'd4' in type 'C4' is not assignable to the same property in base type '({ x, y, z }?: { x: any; y: any; z: any; }) => any'.
+!!! error TS2416: Property 'd4' in type 'C4' is not assignable to the same property in base type 'F2'.
 !!! error TS2416:   Type '({ x, y, c }: { x: any; y: any; c: any; }) => void' is not assignable to type '({ x, y, z }?: { x: any; y: any; z: any; }) => any'.
 !!! error TS2416:     Types of parameters '__0' and '__0' are incompatible.
 !!! error TS2416:       Type '{ x: any; y: any; z: any; }' is not assignable to type '{ x: any; y: any; c: any; }'.

tests/baselines/reference/elaboratedErrors.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/elaboratedErrors.ts(11,3): error TS2416: Property 'read' in type 'WorkerFS' is not assignable to the same property in base type 'number'.
+tests/cases/compiler/elaboratedErrors.ts(11,3): error TS2416: Property 'read' in type 'WorkerFS' is not assignable to the same property in base type 'FileSystem'.
   Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/elaboratedErrors.ts(20,1): error TS2322: Type 'Beta' is not assignable to type 'Alpha'.
   Property 'x' is missing in type 'Beta'.
@@ -21,7 +21,7 @@ tests/cases/compiler/elaboratedErrors.ts(25,1): error TS2322: Type 'Alpha' is no
     class WorkerFS implements FileSystem {
       read: string;
       ~~~~
-!!! error TS2416: Property 'read' in type 'WorkerFS' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'read' in type 'WorkerFS' is not assignable to the same property in base type 'FileSystem'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     

tests/baselines/reference/genericImplements.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/genericImplements.ts(9,5): error TS2416: Property 'f' in type 'X' is not assignable to the same property in base type '<T extends A>() => T'.
+tests/cases/compiler/genericImplements.ts(9,5): error TS2416: Property 'f' in type 'X' is not assignable to the same property in base type 'I'.
   Type '<T extends B>() => T' is not assignable to type '<T extends A>() => T'.
     Type 'B' is not assignable to type 'T'.
 
@@ -14,7 +14,7 @@ tests/cases/compiler/genericImplements.ts(9,5): error TS2416: Property 'f' in ty
     class X implements I {  
         f<T extends B>(): T { return undefined; }
         ~
-!!! error TS2416: Property 'f' in type 'X' is not assignable to the same property in base type '<T extends A>() => T'.
+!!! error TS2416: Property 'f' in type 'X' is not assignable to the same property in base type 'I'.
 !!! error TS2416:   Type '<T extends B>() => T' is not assignable to type '<T extends A>() => T'.
 !!! error TS2416:     Type 'B' is not assignable to type 'T'.
     } // { f: () => { b; } }

tests/baselines/reference/genericSpecializations1.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/compiler/genericSpecializations1.ts(6,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/genericSpecializations1.ts(6,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
   Type '(x: string) => string' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
-tests/cases/compiler/genericSpecializations1.ts(10,5): error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/genericSpecializations1.ts(10,5): error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
   Type '(x: string) => string' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
@@ -16,7 +16,7 @@ tests/cases/compiler/genericSpecializations1.ts(10,5): error TS2416: Property 'f
     class IntFooBad implements IFoo<number> {
         foo(x: string): string { return null; }
         ~~~
-!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
 !!! error TS2416:   Type '(x: string) => string' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.
@@ -25,7 +25,7 @@ tests/cases/compiler/genericSpecializations1.ts(10,5): error TS2416: Property 'f
     class StringFoo2 implements IFoo<string> {
         foo(x: string): string { return null; }
         ~~~
-!!! error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
 !!! error TS2416:   Type '(x: string) => string' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.

tests/baselines/reference/genericSpecializations2.errors.txt

@@ -1,9 +1,9 @@
-tests/cases/compiler/genericSpecializations2.ts(8,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/genericSpecializations2.ts(8,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
   Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
 tests/cases/compiler/genericSpecializations2.ts(8,9): error TS2368: Type parameter name cannot be 'string'.
-tests/cases/compiler/genericSpecializations2.ts(12,5): error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/genericSpecializations2.ts(12,5): error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
   Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
@@ -20,7 +20,7 @@ tests/cases/compiler/genericSpecializations2.ts(12,9): error TS2368: Type parame
     class IntFooBad implements IFoo<number> {
         foo<string>(x: string): string { return null; }
         ~~~
-!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
 !!! error TS2416:   Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.
@@ -31,7 +31,7 @@ tests/cases/compiler/genericSpecializations2.ts(12,9): error TS2368: Type parame
     class StringFoo2 implements IFoo<string> {
         foo<string>(x: string): string { return null; }
         ~~~
-!!! error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
 !!! error TS2416:   Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.

tests/baselines/reference/genericSpecializations3.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/genericSpecializations3.ts(9,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '(x: number) => number'.
+tests/cases/compiler/genericSpecializations3.ts(9,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
   Type '(x: string) => string' is not assignable to type '(x: number) => number'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'number' is not assignable to type 'string'.
@@ -25,7 +25,7 @@ tests/cases/compiler/genericSpecializations3.ts(29,1): error TS2322: Type 'IntFo
     class IntFooBad implements IFoo<number> { // error
         foo(x: string): string { return null; }
         ~~~
-!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type '(x: number) => number'.
+!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
 !!! error TS2416:   Type '(x: string) => string' is not assignable to type '(x: number) => number'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'number' is not assignable to type 'string'.

tests/baselines/reference/genericTypeWithNonGenericBaseMisMatch.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/genericTypeWithNonGenericBaseMisMatch.ts(5,2): error TS2416: Property 'f' in type 'X<T>' is not assignable to the same property in base type '(a: { a: number; }) => void'.
+tests/cases/compiler/genericTypeWithNonGenericBaseMisMatch.ts(5,2): error TS2416: Property 'f' in type 'X<T>' is not assignable to the same property in base type 'I'.
   Type '(a: T) => void' is not assignable to type '(a: { a: number; }) => void'.
     Types of parameters 'a' and 'a' are incompatible.
       Type '{ a: number; }' is not assignable to type 'T'.
@@ -18,7 +18,7 @@ tests/cases/compiler/genericTypeWithNonGenericBaseMisMatch.ts(8,5): error TS2322
     class X<T extends { a: string }> implements I {
     	f(a: T): void { }
     	~
-!!! error TS2416: Property 'f' in type 'X<T>' is not assignable to the same property in base type '(a: { a: number; }) => void'.
+!!! error TS2416: Property 'f' in type 'X<T>' is not assignable to the same property in base type 'I'.
 !!! error TS2416:   Type '(a: T) => void' is not assignable to type '(a: { a: number; }) => void'.
 !!! error TS2416:     Types of parameters 'a' and 'a' are incompatible.
 !!! error TS2416:       Type '{ a: number; }' is not assignable to type 'T'.

tests/baselines/reference/implementGenericWithMismatchedTypes.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/compiler/implementGenericWithMismatchedTypes.ts(8,5): error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type '(x: T) => T'.
+tests/cases/compiler/implementGenericWithMismatchedTypes.ts(8,5): error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type 'IFoo<T>'.
   Type '(x: string) => number' is not assignable to type '(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
-tests/cases/compiler/implementGenericWithMismatchedTypes.ts(17,5): error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type '(x: T) => T'.
+tests/cases/compiler/implementGenericWithMismatchedTypes.ts(17,5): error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type 'IFoo2<T>'.
   Type '<Tstring>(x: Tstring) => number' is not assignable to type '(x: T) => T'.
     Type 'number' is not assignable to type 'T'.
 
@@ -17,7 +17,7 @@ tests/cases/compiler/implementGenericWithMismatchedTypes.ts(17,5): error TS2416:
     class C<T> implements IFoo<T> { // error
         foo(x: string): number {
         ~~~
-!!! error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type '(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type 'IFoo<T>'.
 !!! error TS2416:   Type '(x: string) => number' is not assignable to type '(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.
@@ -31,7 +31,7 @@ tests/cases/compiler/implementGenericWithMismatchedTypes.ts(17,5): error TS2416:
     class C2<T> implements IFoo2<T> { // error
         foo<Tstring>(x: Tstring): number {
         ~~~
-!!! error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type '(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type 'IFoo2<T>'.
 !!! error TS2416:   Type '<Tstring>(x: Tstring) => number' is not assignable to type '(x: T) => T'.
 !!! error TS2416:     Type 'number' is not assignable to type 'T'.
             return null;

tests/baselines/reference/implementsIncorrectlyNoAssertion.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/implementsIncorrectlyNoAssertion.ts(9,5): error TS2416: Property 'x' in type 'Baz' is not assignable to the same property in base type 'string'.
+tests/cases/compiler/implementsIncorrectlyNoAssertion.ts(9,5): error TS2416: Property 'x' in type 'Baz' is not assignable to the same property in base type 'Foo & Bar'.
   Type 'number' is not assignable to type 'string'.
 
 
@@ -13,7 +13,7 @@ tests/cases/compiler/implementsIncorrectlyNoAssertion.ts(9,5): error TS2416: Pro
     class Baz implements Wrapper {
         x: number;
         ~
-!!! error TS2416: Property 'x' in type 'Baz' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'x' in type 'Baz' is not assignable to the same property in base type 'Foo & Bar'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
         y: string;
     }

tests/baselines/reference/incompatibleTypes.errors.txt

@@ -1,13 +1,13 @@
-tests/cases/compiler/incompatibleTypes.ts(6,12): error TS2416: Property 'p1' in type 'C1' is not assignable to the same property in base type '() => number'.
+tests/cases/compiler/incompatibleTypes.ts(6,12): error TS2416: Property 'p1' in type 'C1' is not assignable to the same property in base type 'IFoo1'.
   Type '() => string' is not assignable to type '() => number'.
     Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/incompatibleTypes.ts(16,12): error TS2416: Property 'p1' in type 'C2' is not assignable to the same property in base type '(s: string) => number'.
+tests/cases/compiler/incompatibleTypes.ts(16,12): error TS2416: Property 'p1' in type 'C2' is not assignable to the same property in base type 'IFoo2'.
   Type '(n: number) => number' is not assignable to type '(s: string) => number'.
     Types of parameters 'n' and 's' are incompatible.
       Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/incompatibleTypes.ts(26,12): error TS2416: Property 'p1' in type 'C3' is not assignable to the same property in base type 'string'.
+tests/cases/compiler/incompatibleTypes.ts(26,12): error TS2416: Property 'p1' in type 'C3' is not assignable to the same property in base type 'IFoo3'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/compiler/incompatibleTypes.ts(34,12): error TS2416: Property 'p1' in type 'C4' is not assignable to the same property in base type '{ a: { a: string; }; b: string; }'.
+tests/cases/compiler/incompatibleTypes.ts(34,12): error TS2416: Property 'p1' in type 'C4' is not assignable to the same property in base type 'IFoo4'.
   Type '{ c: { b: string; }; d: string; }' is not assignable to type '{ a: { a: string; }; b: string; }'.
     Property 'a' is missing in type '{ c: { b: string; }; d: string; }'.
 tests/cases/compiler/incompatibleTypes.ts(42,5): error TS2345: Argument of type 'C1' is not assignable to parameter of type 'IFoo2'.
@@ -30,7 +30,7 @@ tests/cases/compiler/incompatibleTypes.ts(74,5): error TS2322: Type '(a: any) =>
     class C1 implements IFoo1 { // incompatible on the return type
         public p1() {
                ~~
-!!! error TS2416: Property 'p1' in type 'C1' is not assignable to the same property in base type '() => number'.
+!!! error TS2416: Property 'p1' in type 'C1' is not assignable to the same property in base type 'IFoo1'.
 !!! error TS2416:   Type '() => string' is not assignable to type '() => number'.
 !!! error TS2416:     Type 'string' is not assignable to type 'number'.
             return "s";
@@ -44,7 +44,7 @@ tests/cases/compiler/incompatibleTypes.ts(74,5): error TS2322: Type '(a: any) =>
     class C2 implements IFoo2 { // incompatible on the param type
         public p1(n:number) {
                ~~
-!!! error TS2416: Property 'p1' in type 'C2' is not assignable to the same property in base type '(s: string) => number'.
+!!! error TS2416: Property 'p1' in type 'C2' is not assignable to the same property in base type 'IFoo2'.
 !!! error TS2416:   Type '(n: number) => number' is not assignable to type '(s: string) => number'.
 !!! error TS2416:     Types of parameters 'n' and 's' are incompatible.
 !!! error TS2416:       Type 'string' is not assignable to type 'number'.
@@ -59,7 +59,7 @@ tests/cases/compiler/incompatibleTypes.ts(74,5): error TS2322: Type '(a: any) =>
     class C3 implements IFoo3 { // incompatible on the property type
         public p1: number;
                ~~
-!!! error TS2416: Property 'p1' in type 'C3' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'p1' in type 'C3' is not assignable to the same property in base type 'IFoo3'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
     }
     
@@ -70,7 +70,7 @@ tests/cases/compiler/incompatibleTypes.ts(74,5): error TS2322: Type '(a: any) =>
     class C4 implements IFoo4 { // incompatible on the property type
         public p1: { c: { b: string; }; d: string; };
                ~~
-!!! error TS2416: Property 'p1' in type 'C4' is not assignable to the same property in base type '{ a: { a: string; }; b: string; }'.
+!!! error TS2416: Property 'p1' in type 'C4' is not assignable to the same property in base type 'IFoo4'.
 !!! error TS2416:   Type '{ c: { b: string; }; d: string; }' is not assignable to type '{ a: { a: string; }; b: string; }'.
 !!! error TS2416:     Property 'a' is missing in type '{ c: { b: string; }; d: string; }'.
     }

tests/baselines/reference/inheritance.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/compiler/inheritance.ts(31,12): error TS2425: Class 'Good' defines instance member property 'f', but extended class 'Baad' defines it as instance member function.
-tests/cases/compiler/inheritance.ts(32,12): error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type '() => number'.
+tests/cases/compiler/inheritance.ts(32,12): error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type 'Good'.
   Type '(n: number) => number' is not assignable to type '() => number'.
 
 
@@ -39,7 +39,7 @@ tests/cases/compiler/inheritance.ts(32,12): error TS2416: Property 'g' in type '
 !!! error TS2425: Class 'Good' defines instance member property 'f', but extended class 'Baad' defines it as instance member function.
         public g(n: number) { return 0; }
                ~
-!!! error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type '() => number'.
+!!! error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type 'Good'.
 !!! error TS2416:   Type '(n: number) => number' is not assignable to type '() => number'.
     }
     

tests/baselines/reference/inheritanceMemberAccessorOverridingMethod.errors.txt

@@ -1,9 +1,9 @@
 tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(8,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
-tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(8,9): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type '() => string'.
+tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(8,9): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
   Type 'string' is not assignable to type '() => string'.
 tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(8,9): error TS2423: Class 'a' defines instance member function 'x', but extended class 'b' defines it as instance member accessor.
 tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(11,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
-tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(11,9): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type '() => string'.
+tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(11,9): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
   Type 'string' is not assignable to type '() => string'.
 
 
@@ -19,7 +19,7 @@ tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(11,9): error T
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
             ~
-!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type '() => string'.
+!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
 !!! error TS2416:   Type 'string' is not assignable to type '() => string'.
             ~
 !!! error TS2423: Class 'a' defines instance member function 'x', but extended class 'b' defines it as instance member accessor.
@@ -29,7 +29,7 @@ tests/cases/compiler/inheritanceMemberAccessorOverridingMethod.ts(11,9): error T
             ~
 !!! error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
             ~
-!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type '() => string'.
+!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
 !!! error TS2416:   Type 'string' is not assignable to type '() => string'.
     
         }

tests/baselines/reference/inheritanceMemberFuncOverridingAccessor.errors.txt

@@ -1,6 +1,6 @@
 tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(2,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
 tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(5,9): error TS1056: Accessors are only available when targeting ECMAScript 5 and higher.
-tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(11,5): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'string'.
+tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(11,5): error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
   Type '() => string' is not assignable to type 'string'.
 tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(11,5): error TS2426: Class 'a' defines instance member accessor 'x', but extended class 'b' defines it as instance member function.
 
@@ -22,7 +22,7 @@ tests/cases/compiler/inheritanceMemberFuncOverridingAccessor.ts(11,5): error TS2
     class b extends a {
         x() {
         ~
-!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'x' in type 'b' is not assignable to the same property in base type 'a'.
 !!! error TS2416:   Type '() => string' is not assignable to type 'string'.
         ~
 !!! error TS2426: Class 'a' defines instance member accessor 'x', but extended class 'b' defines it as instance member function.

tests/baselines/reference/instanceSubtypeCheck2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/instanceSubtypeCheck2.ts(6,5): error TS2416: Property 'x' in type 'C2<T>' is not assignable to the same property in base type 'C2<T>'.
+tests/cases/compiler/instanceSubtypeCheck2.ts(6,5): error TS2416: Property 'x' in type 'C2<T>' is not assignable to the same property in base type 'C1<T>'.
   Type 'string' is not assignable to type 'C2<T>'.
 
 
@@ -10,6 +10,6 @@ tests/cases/compiler/instanceSubtypeCheck2.ts(6,5): error TS2416: Property 'x' i
     class C2<T> extends C1<T> {
         x: string
         ~
-!!! error TS2416: Property 'x' in type 'C2<T>' is not assignable to the same property in base type 'C2<T>'.
+!!! error TS2416: Property 'x' in type 'C2<T>' is not assignable to the same property in base type 'C1<T>'.
 !!! error TS2416:   Type 'string' is not assignable to type 'C2<T>'.
     }

tests/baselines/reference/interfaceDeclaration3.errors.txt

@@ -1,6 +1,6 @@
-tests/cases/compiler/interfaceDeclaration3.ts(7,16): error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'string'.
+tests/cases/compiler/interfaceDeclaration3.ts(7,16): error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'I1'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/compiler/interfaceDeclaration3.ts(32,16): error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'string'.
+tests/cases/compiler/interfaceDeclaration3.ts(32,16): error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'I1'.
   Type 'number' is not assignable to type 'string'.
 tests/cases/compiler/interfaceDeclaration3.ts(54,11): error TS2430: Interface 'I2' incorrectly extends interface 'I1'.
   Types of property 'item' are incompatible.
@@ -16,7 +16,7 @@ tests/cases/compiler/interfaceDeclaration3.ts(54,11): error TS2430: Interface 'I
         class C1 implements I1 {
             public item:number;
                    ~~~~
-!!! error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'I1'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
         }
         class C2 implements I1 {
@@ -44,7 +44,7 @@ tests/cases/compiler/interfaceDeclaration3.ts(54,11): error TS2430: Interface 'I
         class C1 implements I1 {
             public item:number;    
                    ~~~~
-!!! error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'item' in type 'C1' is not assignable to the same property in base type 'I1'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
         }
         class C2 implements I1 {

tests/baselines/reference/interfaceExtendsClassWithPrivate2.errors.txt

@@ -2,11 +2,13 @@ tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(10,7): error TS2415: C
   Types have separate declarations of a private property 'x'.
 tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(10,7): error TS2420: Class 'D' incorrectly implements interface 'I'.
   Types have separate declarations of a private property 'x'.
-tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(20,13): error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'number'.
+tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(20,13): error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'C'.
+  Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(20,13): error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'I'.
   Type 'string' is not assignable to type 'number'.
 
 
-==== tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts (3 errors) ====
+==== tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts (4 errors) ====
     class C {
         public foo(x: any) { return x; }
         private x = 1;
@@ -34,7 +36,10 @@ tests/cases/compiler/interfaceExtendsClassWithPrivate2.ts(20,13): error TS2416:
         public foo(x: any) { return x; }
         private x = "";
                 ~
-!!! error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'C'.
+!!! error TS2416:   Type 'string' is not assignable to type 'number'.
+                ~
+!!! error TS2416: Property 'x' in type 'D2' is not assignable to the same property in base type 'I'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
         other(x: any) { return x; }
         bar() { }

tests/baselines/reference/interfaceExtendsObjectIntersectionErrors.errors.txt

@@ -14,15 +14,15 @@ tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectI
 tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(11,11): error TS2430: Interface 'I5' incorrectly extends interface 'T5'.
   Types of property 'c' are incompatible.
     Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(16,38): error TS2416: Property 'a' in type 'C1' is not assignable to the same property in base type 'number'.
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(16,38): error TS2416: Property 'a' in type 'C1' is not assignable to the same property in base type 'T1'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(17,38): error TS2416: Property 'b' in type 'C2' is not assignable to the same property in base type 'number'.
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(17,38): error TS2416: Property 'b' in type 'C2' is not assignable to the same property in base type 'T2'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(18,38): error TS2416: Property 'length' in type 'C3' is not assignable to the same property in base type 'number'.
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(18,38): error TS2416: Property 'length' in type 'C3' is not assignable to the same property in base type 'number[]'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(19,38): error TS2416: Property '0' in type 'C4' is not assignable to the same property in base type 'string'.
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(19,38): error TS2416: Property '0' in type 'C4' is not assignable to the same property in base type '[string, number]'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(20,38): error TS2416: Property 'c' in type 'C5' is not assignable to the same property in base type 'string'.
+tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(20,38): error TS2416: Property 'c' in type 'C5' is not assignable to the same property in base type 'T5'.
   Type 'number' is not assignable to type 'string'.
 tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectIntersectionErrors.ts(30,11): error TS2430: Interface 'I10' incorrectly extends interface 'typeof CX'.
   Types of property 'a' are incompatible.
@@ -94,23 +94,23 @@ tests/cases/conformance/interfaces/interfaceDeclarations/interfaceExtendsObjectI
     
     class C1 extends Constructor<T1>() { a: string }
                                          ~
-!!! error TS2416: Property 'a' in type 'C1' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'a' in type 'C1' is not assignable to the same property in base type 'T1'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     class C2 extends Constructor<T2>() { b: string }
                                          ~
-!!! error TS2416: Property 'b' in type 'C2' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'b' in type 'C2' is not assignable to the same property in base type 'T2'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     class C3 extends Constructor<T3>() { length: string }
                                          ~~~~~~
-!!! error TS2416: Property 'length' in type 'C3' is not assignable to the same property in base type 'number'.
+!!! error TS2416: Property 'length' in type 'C3' is not assignable to the same property in base type 'number[]'.
 !!! error TS2416:   Type 'string' is not assignable to type 'number'.
     class C4 extends Constructor<T4>() { 0: number }
                                          ~
-!!! error TS2416: Property '0' in type 'C4' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property '0' in type 'C4' is not assignable to the same property in base type '[string, number]'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
     class C5 extends Constructor<T5>() { c: number }
                                          ~
-!!! error TS2416: Property 'c' in type 'C5' is not assignable to the same property in base type 'string'.
+!!! error TS2416: Property 'c' in type 'C5' is not assignable to the same property in base type 'T5'.
 !!! error TS2416:   Type 'number' is not assignable to type 'string'.
     
     declare class CX { static a: string }

tests/baselines/reference/interfaceImplementation7.errors.txt

@@ -1,6 +1,6 @@
 tests/cases/compiler/interfaceImplementation7.ts(4,11): error TS2320: Interface 'i3' cannot simultaneously extend types 'i1' and 'i2'.
   Named property 'name' of types 'i1' and 'i2' are not identical.
-tests/cases/compiler/interfaceImplementation7.ts(8,12): error TS2416: Property 'name' in type 'C1' is not assignable to the same property in base type '() => { s: string; n: number; }'.
+tests/cases/compiler/interfaceImplementation7.ts(8,12): error TS2416: Property 'name' in type 'C1' is not assignable to the same property in base type 'i4'.
   Type '() => string' is not assignable to type '() => { s: string; n: number; }'.
     Type 'string' is not assignable to type '{ s: string; n: number; }'.
 
@@ -18,7 +18,7 @@ tests/cases/compiler/interfaceImplementation7.ts(8,12): error TS2416: Property '
     class C1 implements i4 {
         public name(): string { return ""; }
                ~~~~
-!!! error TS2416: Property 'name' in type 'C1' is not assignable to the same property in base type '() => { s: string; n: number; }'.
+!!! error TS2416: Property 'name' in type 'C1' is not assignable to the same property in base type 'i4'.
 !!! error TS2416:   Type '() => string' is not assignable to type '() => { s: string; n: number; }'.
 !!! error TS2416:     Type 'string' is not assignable to type '{ s: string; n: number; }'.
     }

tests/baselines/reference/jsxHasLiteralType.js

@@ -0,0 +1,32 @@
+//// [jsxHasLiteralType.tsx]
+import * as React from "react";
+
+interface Props {
+    x?: "a" | "b";
+}
+class MyComponent<P extends Props = Props> extends React.Component<P, {}> {}
+const m = <MyComponent x="a"/>
+
+
+//// [jsxHasLiteralType.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+var React = require("react");
+var MyComponent = /** @class */ (function (_super) {
+    __extends(MyComponent, _super);
+    function MyComponent() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return MyComponent;
+}(React.Component));
+var m = React.createElement(MyComponent, { x: "a" });

tests/baselines/reference/jsxHasLiteralType.symbols

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/jsxHasLiteralType.tsx ===
+import * as React from "react";
+>React : Symbol(React, Decl(jsxHasLiteralType.tsx, 0, 6))
+
+interface Props {
+>Props : Symbol(Props, Decl(jsxHasLiteralType.tsx, 0, 31))
+
+    x?: "a" | "b";
+>x : Symbol(Props.x, Decl(jsxHasLiteralType.tsx, 2, 17))
+}
+class MyComponent<P extends Props = Props> extends React.Component<P, {}> {}
+>MyComponent : Symbol(MyComponent, Decl(jsxHasLiteralType.tsx, 4, 1))
+>P : Symbol(P, Decl(jsxHasLiteralType.tsx, 5, 18))
+>Props : Symbol(Props, Decl(jsxHasLiteralType.tsx, 0, 31))
+>Props : Symbol(Props, Decl(jsxHasLiteralType.tsx, 0, 31))
+>React.Component : Symbol(React.Component, Decl(react.d.ts, 158, 55), Decl(react.d.ts, 161, 66))
+>React : Symbol(React, Decl(jsxHasLiteralType.tsx, 0, 6))
+>Component : Symbol(React.Component, Decl(react.d.ts, 158, 55), Decl(react.d.ts, 161, 66))
+>P : Symbol(P, Decl(jsxHasLiteralType.tsx, 5, 18))
+
+const m = <MyComponent x="a"/>
+>m : Symbol(m, Decl(jsxHasLiteralType.tsx, 6, 5))
+>MyComponent : Symbol(MyComponent, Decl(jsxHasLiteralType.tsx, 4, 1))
+>x : Symbol(x, Decl(jsxHasLiteralType.tsx, 6, 22))
+

tests/baselines/reference/jsxHasLiteralType.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/jsxHasLiteralType.tsx ===
+import * as React from "react";
+>React : typeof React
+
+interface Props {
+>Props : Props
+
+    x?: "a" | "b";
+>x : "a" | "b" | undefined
+}
+class MyComponent<P extends Props = Props> extends React.Component<P, {}> {}
+>MyComponent : MyComponent<P>
+>P : P
+>Props : Props
+>Props : Props
+>React.Component : React.Component<P, {}>
+>React : typeof React
+>Component : typeof React.Component
+>P : P
+
+const m = <MyComponent x="a"/>
+>m : JSX.Element
+><MyComponent x="a"/> : JSX.Element
+>MyComponent : typeof MyComponent
+>x : "a"
+

tests/baselines/reference/mismatchedGenericArguments1.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/compiler/mismatchedGenericArguments1.ts(5,4): error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/mismatchedGenericArguments1.ts(5,4): error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type 'IFoo<T>'.
   Type '(x: string) => number' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
-tests/cases/compiler/mismatchedGenericArguments1.ts(11,4): error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type '<T>(x: T) => T'.
+tests/cases/compiler/mismatchedGenericArguments1.ts(11,4): error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type 'IFoo<T>'.
   Type '<U>(x: string) => number' is not assignable to type '<T>(x: T) => T'.
     Types of parameters 'x' and 'x' are incompatible.
       Type 'T' is not assignable to type 'string'.
@@ -15,7 +15,7 @@ tests/cases/compiler/mismatchedGenericArguments1.ts(11,4): error TS2416: Propert
     class C<T> implements IFoo<T> {
        foo(x: string): number {
        ~~~
-!!! error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'C<T>' is not assignable to the same property in base type 'IFoo<T>'.
 !!! error TS2416:   Type '(x: string) => number' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.
@@ -26,7 +26,7 @@ tests/cases/compiler/mismatchedGenericArguments1.ts(11,4): error TS2416: Propert
     class C2<T> implements IFoo<T> {
        foo<U>(x: string): number {
        ~~~
-!!! error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type '<T>(x: T) => T'.
+!!! error TS2416: Property 'foo' in type 'C2<T>' is not assignable to the same property in base type 'IFoo<T>'.
 !!! error TS2416:   Type '<U>(x: string) => number' is not assignable to type '<T>(x: T) => T'.
 !!! error TS2416:     Types of parameters 'x' and 'x' are incompatible.
 !!! error TS2416:       Type 'T' is not assignable to type 'string'.

tests/baselines/reference/multipleInheritance.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/multipleInheritance.ts(9,21): error TS1174: Classes can only extend a single class.
 tests/cases/compiler/multipleInheritance.ts(18,21): error TS1174: Classes can only extend a single class.
 tests/cases/compiler/multipleInheritance.ts(35,12): error TS2425: Class 'Good' defines instance member property 'f', but extended class 'Baad' defines it as instance member function.
-tests/cases/compiler/multipleInheritance.ts(36,12): error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type '() => number'.
+tests/cases/compiler/multipleInheritance.ts(36,12): error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type 'Good'.
   Type '(n: number) => number' is not assignable to type '() => number'.
 
 
@@ -49,7 +49,7 @@ tests/cases/compiler/multipleInheritance.ts(36,12): error TS2416: Property 'g' i
 !!! error TS2425: Class 'Good' defines instance member property 'f', but extended class 'Baad' defines it as instance member function.
         public g(n:number) { return 0; }
                ~
-!!! error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type '() => number'.
+!!! error TS2416: Property 'g' in type 'Baad' is not assignable to the same property in base type 'Good'.
 !!! error TS2416:   Type '(n: number) => number' is not assignable to type '() => number'.
     }
     

tests/baselines/reference/requiredInitializedParameter2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/requiredInitializedParameter2.ts(6,5): error TS2416: Property 'method' in type 'C1' is not assignable to the same property in base type '() => any'.
+tests/cases/compiler/requiredInitializedParameter2.ts(6,5): error TS2416: Property 'method' in type 'C1' is not assignable to the same property in base type 'I1'.
   Type '(a: number, b: any) => void' is not assignable to type '() => any'.
 
 
@@ -10,6 +10,6 @@ tests/cases/compiler/requiredInitializedParameter2.ts(6,5): error TS2416: Proper
     class C1 implements I1 {
         method(a = 0, b) { }
         ~~~~~~
-!!! error TS2416: Property 'method' in type 'C1' is not assignable to the same property in base type '() => any'.
+!!! error TS2416: Property 'method' in type 'C1' is not assignable to the same property in base type 'I1'.
 !!! error TS2416:   Type '(a: number, b: any) => void' is not assignable to type '() => any'.
     }

tests/baselines/reference/subtypesOfTypeParameter.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameter.ts(8,5): error TS2416: Property 'foo' in type 'D1<T, U>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameter.ts(8,5): error TS2416: Property 'foo' in type 'D1<T, U>' is not assignable to the same property in base type 'C3<T>'.
   Type 'U' is not assignable to type 'T'.
 
 
@@ -12,7 +12,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
     class D1<T, U> extends C3<T> {
         foo: U; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D1<T, U>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D1<T, U>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
     }
     

tests/baselines/reference/subtypesOfTypeParameterWithConstraints.errors.txt

@@ -1,36 +1,36 @@
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(19,5): error TS2416: Property 'foo' in type 'D3<T, U>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(19,5): error TS2416: Property 'foo' in type 'D3<T, U>' is not assignable to the same property in base type 'C3<T>'.
   Type 'U' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(19,5): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(50,5): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(50,5): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
   Type 'U' is not assignable to type 'T'.
     Type 'V' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(50,5): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(67,5): error TS2416: Property 'foo' in type 'D11<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(67,5): error TS2416: Property 'foo' in type 'D11<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
   Type 'V' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(67,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(72,5): error TS2416: Property 'foo' in type 'D12<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(72,5): error TS2416: Property 'foo' in type 'D12<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
   Type 'V' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(72,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(112,5): error TS2416: Property 'foo' in type 'D19<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(112,5): error TS2416: Property 'foo' in type 'D19<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
   Type 'U' is not assignable to type 'T'.
     Type 'V' is not assignable to type 'T'.
       Type 'Date' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(112,5): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(134,5): error TS2416: Property 'foo' in type 'D23<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(134,5): error TS2416: Property 'foo' in type 'D23<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
   Type 'V' is not assignable to type 'T'.
     Type 'Date' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(134,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(139,5): error TS2416: Property 'foo' in type 'D24<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(139,5): error TS2416: Property 'foo' in type 'D24<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
   Type 'V' is not assignable to type 'U'.
     Type 'Date' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(139,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(156,5): error TS2416: Property 'foo' in type 'D27<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(156,5): error TS2416: Property 'foo' in type 'D27<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
   Type 'Date' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(156,5): error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(161,5): error TS2416: Property 'foo' in type 'D28<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(161,5): error TS2416: Property 'foo' in type 'D28<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
   Type 'Date' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(161,5): error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(166,5): error TS2416: Property 'foo' in type 'D29<T, U, V>' is not assignable to the same property in base type 'V'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(166,5): error TS2416: Property 'foo' in type 'D29<T, U, V>' is not assignable to the same property in base type 'C3<V>'.
   Type 'Date' is not assignable to type 'V'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints.ts(166,5): error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'V'.
 
@@ -56,7 +56,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: U; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D3<T, U>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D3<T, U>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
@@ -92,7 +92,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: U; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
 !!! error TS2416:     Type 'V' is not assignable to type 'T'.
         ~~~~~~~
@@ -115,7 +115,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D11<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D11<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'T'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
@@ -125,7 +125,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: U;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D12<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D12<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'U'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
@@ -170,7 +170,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: U; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D19<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D19<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
 !!! error TS2416:     Type 'V' is not assignable to type 'T'.
 !!! error TS2416:       Type 'Date' is not assignable to type 'T'.
@@ -199,7 +199,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D23<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D23<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'T'.
 !!! error TS2416:     Type 'Date' is not assignable to type 'T'.
         ~~~~~~~
@@ -210,7 +210,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: U;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D24<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D24<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'U'.
 !!! error TS2416:     Type 'Date' is not assignable to type 'U'.
         ~~~~~~~
@@ -233,7 +233,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: Date; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D27<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D27<T, U, V>' is not assignable to the same property in base type 'C3<T>'.
 !!! error TS2416:   Type 'Date' is not assignable to type 'T'.
         ~~~~~~~~~~
 !!! error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'T'.
@@ -243,7 +243,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: U;
         foo: Date; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D28<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D28<T, U, V>' is not assignable to the same property in base type 'C3<U>'.
 !!! error TS2416:   Type 'Date' is not assignable to type 'U'.
         ~~~~~~~~~~
 !!! error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'U'.
@@ -253,7 +253,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: V;
         foo: Date; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D29<T, U, V>' is not assignable to the same property in base type 'V'.
+!!! error TS2416: Property 'foo' in type 'D29<T, U, V>' is not assignable to the same property in base type 'C3<V>'.
 !!! error TS2416:   Type 'Date' is not assignable to type 'V'.
         ~~~~~~~~~~
 !!! error TS2411: Property 'foo' of type 'Date' is not assignable to string index type 'V'.

tests/baselines/reference/subtypesOfTypeParameterWithConstraints4.errors.txt

@@ -1,18 +1,18 @@
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(47,5): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Foo'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(47,5): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'B1<Foo>'.
   Type 'V' is not assignable to type 'Foo'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(47,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'Foo'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(57,5): error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(57,5): error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'B1<T>'.
   Type 'U' is not assignable to type 'T'.
     Type 'Foo' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(57,5): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(62,5): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(62,5): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'B1<T>'.
   Type 'V' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(62,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(67,5): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(67,5): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'B1<U>'.
   Type 'T' is not assignable to type 'U'.
     Type 'Foo' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(67,5): error TS2411: Property 'foo' of type 'T' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(77,5): error TS2416: Property 'foo' in type 'D9<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(77,5): error TS2416: Property 'foo' in type 'D9<T, U, V>' is not assignable to the same property in base type 'B1<U>'.
   Type 'V' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithConstraints4.ts(77,5): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
 
@@ -66,7 +66,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: Foo;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Foo'.
+!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'B1<Foo>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'Foo'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'Foo'.
@@ -81,7 +81,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: U; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'B1<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
 !!! error TS2416:     Type 'Foo' is not assignable to type 'T'.
         ~~~~~~~
@@ -92,7 +92,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: T;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'B1<T>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'T'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
@@ -102,7 +102,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: U;
         foo: T; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'B1<U>'.
 !!! error TS2416:   Type 'T' is not assignable to type 'U'.
 !!! error TS2416:     Type 'Foo' is not assignable to type 'U'.
         ~~~~~~~
@@ -118,7 +118,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
         [x: string]: U;
         foo: V; // error
         ~~~
-!!! error TS2416: Property 'foo' in type 'D9<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D9<T, U, V>' is not assignable to the same property in base type 'B1<U>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'U'.
         ~~~~~~~
 !!! error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.

tests/baselines/reference/subtypesOfTypeParameterWithRecursiveConstraints.errors.txt

@@ -1,58 +1,58 @@
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(68,9): error TS2416: Property 'foo' in type 'D2<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(68,9): error TS2416: Property 'foo' in type 'D2<T, U, V>' is not assignable to the same property in base type 'Base<T>'.
   Type 'U' is not assignable to type 'T'.
     Type 'Foo<T>' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(68,9): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(73,9): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'T'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(73,9): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Base<T>'.
   Type 'V' is not assignable to type 'T'.
     Type 'Foo<V>' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(73,9): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(78,9): error TS2416: Property 'foo' in type 'D4<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(78,9): error TS2416: Property 'foo' in type 'D4<T, U, V>' is not assignable to the same property in base type 'Base<U>'.
   Type 'T' is not assignable to type 'U'.
     Type 'Foo<U>' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(78,9): error TS2411: Property 'foo' of type 'T' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(88,9): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'U'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(88,9): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Base<U>'.
   Type 'V' is not assignable to type 'U'.
     Type 'Foo<V>' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(88,9): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(93,9): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'V'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(93,9): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Base<V>'.
   Type 'T' is not assignable to type 'V'.
     Type 'Foo<U>' is not assignable to type 'V'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(93,9): error TS2411: Property 'foo' of type 'T' is not assignable to string index type 'V'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(98,9): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'V'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(98,9): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Base<V>'.
   Type 'U' is not assignable to type 'V'.
     Type 'Foo<T>' is not assignable to type 'V'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(98,9): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'V'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(115,9): error TS2416: Property 'foo' in type 'D1<T, U, V>' is not assignable to the same property in base type 'Foo<T>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(115,9): error TS2416: Property 'foo' in type 'D1<T, U, V>' is not assignable to the same property in base type 'Base2<T>'.
   Type 'T' is not assignable to type 'Foo<T>'.
     Type 'Foo<U>' is not assignable to type 'Foo<T>'.
       Type 'U' is not assignable to type 'T'.
         Type 'Foo<T>' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(120,9): error TS2411: Property 'foo' of type 'U' is not assignable to string index type 'T'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(125,9): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Foo<T>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(125,9): error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Base2<T>'.
   Type 'V' is not assignable to type 'Foo<T>'.
     Type 'Foo<V>' is not assignable to type 'Foo<T>'.
       Type 'V' is not assignable to type 'T'.
         Type 'Foo<V>' is not assignable to type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(125,9): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'T'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(130,9): error TS2411: Property 'foo' of type 'T' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(135,9): error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'Foo<U>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(135,9): error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'Base2<U>'.
   Type 'U' is not assignable to type 'Foo<U>'.
     Type 'Foo<T>' is not assignable to type 'Foo<U>'.
       Type 'T' is not assignable to type 'U'.
         Type 'Foo<U>' is not assignable to type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(140,9): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Foo<U>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(140,9): error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Base2<U>'.
   Type 'V' is not assignable to type 'Foo<U>'.
     Type 'Foo<V>' is not assignable to type 'Foo<U>'.
       Type 'V' is not assignable to type 'U'.
         Type 'Foo<V>' is not assignable to type 'U'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(140,9): error TS2411: Property 'foo' of type 'V' is not assignable to string index type 'U'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(145,9): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Foo<V>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(145,9): error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Base2<V>'.
   Type 'T' is not assignable to type 'Foo<V>'.
     Type 'Foo<U>' is not assignable to type 'Foo<V>'.
       Type 'U' is not assignable to type 'V'.
         Type 'Foo<T>' is not assignable to type 'V'.
 tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(145,9): error TS2411: Property 'foo' of type 'T' is not assignable to string index type 'V'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(150,9): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Foo<V>'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOfTypeParameterWithRecursiveConstraints.ts(150,9): error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Base2<V>'.
   Type 'U' is not assignable to type 'Foo<V>'.
     Type 'Foo<T>' is not assignable to type 'Foo<V>'.
       Type 'T' is not assignable to type 'V'.
@@ -130,7 +130,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: T;
             foo: U
             ~~~
-!!! error TS2416: Property 'foo' in type 'D2<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D2<T, U, V>' is not assignable to the same property in base type 'Base<T>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'T'.
 !!! error TS2416:     Type 'Foo<T>' is not assignable to type 'T'.
             ~~~~~~
@@ -141,7 +141,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: T;
             foo: V
             ~~~
-!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'T'.
+!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Base<T>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'T'.
 !!! error TS2416:     Type 'Foo<V>' is not assignable to type 'T'.
             ~~~~~~
@@ -152,7 +152,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: U;
             foo: T
             ~~~
-!!! error TS2416: Property 'foo' in type 'D4<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D4<T, U, V>' is not assignable to the same property in base type 'Base<U>'.
 !!! error TS2416:   Type 'T' is not assignable to type 'U'.
 !!! error TS2416:     Type 'Foo<U>' is not assignable to type 'U'.
             ~~~~~~
@@ -168,7 +168,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: U;
             foo: V
             ~~~
-!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'U'.
+!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Base<U>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'U'.
 !!! error TS2416:     Type 'Foo<V>' is not assignable to type 'U'.
             ~~~~~~
@@ -179,7 +179,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: V;
             foo: T
             ~~~
-!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'V'.
+!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Base<V>'.
 !!! error TS2416:   Type 'T' is not assignable to type 'V'.
 !!! error TS2416:     Type 'Foo<U>' is not assignable to type 'V'.
             ~~~~~~
@@ -190,7 +190,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: V;
             foo: U
             ~~~
-!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'V'.
+!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Base<V>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'V'.
 !!! error TS2416:     Type 'Foo<T>' is not assignable to type 'V'.
             ~~~~~~
@@ -213,7 +213,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: T;
             foo: T
             ~~~
-!!! error TS2416: Property 'foo' in type 'D1<T, U, V>' is not assignable to the same property in base type 'Foo<T>'.
+!!! error TS2416: Property 'foo' in type 'D1<T, U, V>' is not assignable to the same property in base type 'Base2<T>'.
 !!! error TS2416:   Type 'T' is not assignable to type 'Foo<T>'.
 !!! error TS2416:     Type 'Foo<U>' is not assignable to type 'Foo<T>'.
 !!! error TS2416:       Type 'U' is not assignable to type 'T'.
@@ -231,7 +231,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: T;
             foo: V
             ~~~
-!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Foo<T>'.
+!!! error TS2416: Property 'foo' in type 'D3<T, U, V>' is not assignable to the same property in base type 'Base2<T>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'Foo<T>'.
 !!! error TS2416:     Type 'Foo<V>' is not assignable to type 'Foo<T>'.
 !!! error TS2416:       Type 'V' is not assignable to type 'T'.
@@ -251,7 +251,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: U;
             foo: U
             ~~~
-!!! error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'Foo<U>'.
+!!! error TS2416: Property 'foo' in type 'D5<T, U, V>' is not assignable to the same property in base type 'Base2<U>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'Foo<U>'.
 !!! error TS2416:     Type 'Foo<T>' is not assignable to type 'Foo<U>'.
 !!! error TS2416:       Type 'T' is not assignable to type 'U'.
@@ -262,7 +262,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: U;
             foo: V
             ~~~
-!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Foo<U>'.
+!!! error TS2416: Property 'foo' in type 'D6<T, U, V>' is not assignable to the same property in base type 'Base2<U>'.
 !!! error TS2416:   Type 'V' is not assignable to type 'Foo<U>'.
 !!! error TS2416:     Type 'Foo<V>' is not assignable to type 'Foo<U>'.
 !!! error TS2416:       Type 'V' is not assignable to type 'U'.
@@ -275,7 +275,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: V;
             foo: T
             ~~~
-!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Foo<V>'.
+!!! error TS2416: Property 'foo' in type 'D7<T, U, V>' is not assignable to the same property in base type 'Base2<V>'.
 !!! error TS2416:   Type 'T' is not assignable to type 'Foo<V>'.
 !!! error TS2416:     Type 'Foo<U>' is not assignable to type 'Foo<V>'.
 !!! error TS2416:       Type 'U' is not assignable to type 'V'.
@@ -288,7 +288,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypesOf
             [x: string]: V;
             foo: U
             ~~~
-!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Foo<V>'.
+!!! error TS2416: Property 'foo' in type 'D8<T, U, V>' is not assignable to the same property in base type 'Base2<V>'.
 !!! error TS2416:   Type 'U' is not assignable to type 'Foo<V>'.
 !!! error TS2416:     Type 'Foo<T>' is not assignable to type 'Foo<V>'.
 !!! error TS2416:       Type 'T' is not assignable to type 'V'.

tests/baselines/reference/subtypingWithObjectMembers.errors.txt

@@ -1,14 +1,14 @@
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(14,5): error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(14,5): error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'A'.
   Type 'string' is not assignable to type 'Base'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(24,5): error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(24,5): error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'A2'.
   Type 'string' is not assignable to type 'Base'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(34,5): error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(34,5): error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'A3'.
   Type 'string' is not assignable to type 'Base'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(45,9): error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(45,9): error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'A'.
   Type 'string' is not assignable to type 'Base'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(55,9): error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(55,9): error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'A2'.
   Type 'string' is not assignable to type 'Base'.
-tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(65,9): error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'Base'.
+tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithObjectMembers.ts(65,9): error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'A3'.
   Type 'string' is not assignable to type 'Base'.
 
 
@@ -28,7 +28,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
         foo: Derived; // ok
         bar: string; // error
         ~~~
-!!! error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'A'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
     }
     
@@ -41,7 +41,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
         1: Derived; // ok
         2: string; // error
         ~
-!!! error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'A2'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
     }
     
@@ -54,7 +54,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
         '1': Derived; // ok
         '2.0': string; // error
         ~~~~~
-!!! error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'A3'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
     }
     
@@ -68,7 +68,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
             foo: Derived2; // ok
             bar: string; // error
             ~~~
-!!! error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property 'bar' in type 'B' is not assignable to the same property in base type 'A'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
         }
     
@@ -81,7 +81,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
             1: Derived2; // ok
             2: string; // error
             ~
-!!! error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property '2' in type 'B2' is not assignable to the same property in base type 'A2'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
         }
     
@@ -94,7 +94,7 @@ tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingW
             '1': Derived2; // ok
             '2.0': string; // error
             ~~~~~
-!!! error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'Base'.
+!!! error TS2416: Property '2.0' in type 'B3' is not assignable to the same property in base type 'A3'.
 !!! error TS2416:   Type 'string' is not assignable to type 'Base'.
         }
     }

tests/cases/compiler/anyMappedTypesError.ts

@@ -0,0 +1,3 @@
+// @noImplicitAny: true
+
+type Foo = {[P in "bar"]};

tests/cases/compiler/jsxHasLiteralType.tsx

@@ -0,0 +1,11 @@
+// @strictNullChecks: true
+// @jsx: react
+// @skipLibCheck: true
+// @libFiles: lib.d.ts,react.d.ts
+import * as React from "react";
+
+interface Props {
+    x?: "a" | "b";
+}
+class MyComponent<P extends Props = Props> extends React.Component<P, {}> {}
+const m = <MyComponent x="a"/>

tests/cases/fourslash/codeFixAwaitInSyncFunction1.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////function f() {
+////    await Promise.resolve();
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`async function f() {
+    await Promise.resolve();
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction10.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f: () => number | string = () => {
+////    await Promise.resolve('foo');
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f: () => Promise<number | string> = async () => {
+    await Promise.resolve('foo');
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction11.ts

@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts' />
+
+////const f: string = () => {
+////    await Promise.resolve('foo');
+////}
+
+// should not change type if it's incorrectly set
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f: string = async () => {
+    await Promise.resolve('foo');
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction12.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f: () => Array<number | string> = function() {
+////    await Promise.resolve([]);
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f: () => Promise<Array<number | string>> = async function() {
+    await Promise.resolve([]);
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction13.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f: () => Promise<number | string> = () => {
+////    await Promise.resolve('foo');
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f: () => Promise<number | string> = async () => {
+    await Promise.resolve('foo');
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction14.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f = function(): number {
+////    await Promise.resolve(1);
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f = async function(): Promise<number> {
+    await Promise.resolve(1);
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction15.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f = (): number[] => {
+////    await Promise.resolve([1]);
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f = async (): Promise<number[]> => {
+    await Promise.resolve([1]);
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction2.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f = function() {
+////    await Promise.resolve();
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f = async function() {
+    await Promise.resolve();
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction3.ts

@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts' />
+
+////const f = {
+////    get a() {
+////        return await Promise.resolve();
+////    },
+////    get a() {
+////        await Promise.resolve();
+////    },
+////}
+
+verify.not.codeFixAvailable();

tests/cases/fourslash/codeFixAwaitInSyncFunction4.ts

@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+
+////class Foo {
+////    constructor {
+////        await Promise.resolve();
+////    }
+////}
+
+verify.not.codeFixAvailable();

tests/cases/fourslash/codeFixAwaitInSyncFunction5.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+////class Foo {
+////    bar() {
+////        await Promise.resolve();
+////    }
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`class Foo {
+    async bar() {
+        await Promise.resolve();
+    }
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction6.5.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f = promise => {
+////    await promise;
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f = async promise => {
+    await promise;
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction6.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////const f = (promise) => {
+////    await promise;
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`const f = async (promise) => {
+    await promise;
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction7.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+////function f() {
+////    for await (const x of g()) {
+////        console.log(x);
+////    }
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`async function f() {
+    for await (const x of g()) {
+        console.log(x);
+    }
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction8.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+////function f(): number | string {
+////    await Promise.resolve(8);
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`async function f(): Promise<number | string> {
+    await Promise.resolve(8);
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction9.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+////class Foo {
+////    bar(): string {
+////        await Promise.resolve('baz');
+////    }
+////}
+
+verify.codeFix({
+    description: "Add async modifier to containing function",
+    newFileContent:
+`class Foo {
+    async bar(): Promise<string> {
+        await Promise.resolve('baz');
+    }
+}`,
+});

tests/cases/fourslash/codeFixAwaitInSyncFunction_all.ts

@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts' />
+
+////function f() {
+////    await Promise.resolve();
+////}
+////
+////const g = () => {
+////    await f();
+////}
+
+verify.codeFixAll({
+    fixId: "fixAwaitInSyncFunction",
+    newFileContent:
+`async function f() {
+    await Promise.resolve();
+}
+
+const g = async () => {
+    await f();
+}`,
+});

tests/cases/fourslash/completionsPaths_pathMapping.ts

@@ -3,6 +3,9 @@
 // @Filename: /src/b.ts
 ////export const x = 0;
 
+// @Filename: /src/dir/x.ts
+/////export const x = 0;
+
 // @Filename: /src/a.ts
 ////import {} from "foo/[|/**/|]";
 
@@ -17,4 +20,8 @@
 ////}
 
 const [replacementSpan] = test.ranges();
-verify.completionsAt("", [{ name: "a", replacementSpan }, { name: "b", replacementSpan }]);
+verify.completionsAt("", [
+    { name: "a", replacementSpan },
+    { name: "b", replacementSpan },
+    { name: "dir", replacementSpan },
+]);

tests/cases/fourslash/fourslash.ts

@@ -135,6 +135,7 @@ declare namespace FourSlashInterface {
         file(index: number, content?: string, scriptKindName?: string): any;
         file(name: string, content?: string, scriptKindName?: string): any;
         select(startMarker: string, endMarker: string): void;
+        selectRange(range: Range): void;
     }
     class verifyNegatable {
         private negative;

tests/cases/fourslash/refactorConvertToEs6Module_export_alias.ts

@@ -0,0 +1,18 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+////const exportsAlias = exports;
+////exportsAlias.f = function() {};
+/////*a*/module/*b*/.exports = exportsAlias;
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `
+export function f() { }
+`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_dotDefault.ts

@@ -0,0 +1,19 @@
+/// <reference path='fourslash.ts' />
+
+// Test that we leave it alone if the name is a keyword.
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/exports/*b*/.default = 0;
+////exports.default;
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `const _default = 0;
+export { _default as default };
+_default;`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_invalidName.ts

@@ -0,0 +1,19 @@
+/// <reference path='fourslash.ts' />
+
+// Test that we leave it alone if the name is a keyword.
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/exports/*b*/.class = 0;
+////exports.async = 1;
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `const _class = 0;
+export { _class as class };
+export const async = 1;`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_moduleDotExports.ts

@@ -0,0 +1,26 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/module/*b*/.exports = function() {}
+////module.exports = function f() {}
+////module.exports = class {}
+////module.exports = class C {}
+////module.exports = 0;
+
+// See also `refactorConvertToEs6Module_export_moduleDotExportsEqualsRequire.ts`
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export default function() { }
+export default function f() { }
+export default class {
+}
+export default class C {
+}
+export default 0;`
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_moduleDotExportsEqualsRequire.ts

@@ -0,0 +1,43 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.d.ts
+////export const x: number;
+
+// @Filename: /b.d.ts
+////export default function f() {}
+
+// @Filename: /c.d.ts
+////export default function f(): void;
+////export function g(): void;
+
+// @Filename: /d.ts
+////declare const x: number;
+////export = x;
+
+// @Filename: /z.js
+// Normally -- just `export *`
+/////*a*/module/*b*/.exports = require("./a");
+// If just a default is exported, just `export { default }`
+////module.exports = require("./b");
+// May need both
+////module.exports = require("./c");
+// For `export =` re-export the "default" since that's what it will be converted to.
+////module.exports = require("./d");
+// In untyped case just go with `export *`
+////module.exports = require("./unknown");
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent:
+`export * from "./a";
+export { default } from "./b";
+export * from "./c";
+export { default } from "./c";
+export { default } from "./d";
+export * from "./unknown";`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_moduleDotExports_changesImports.ts

@@ -0,0 +1,26 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/module/*b*/.exports = 0;
+
+// @Filename: /b.ts
+////import a = require("./a");
+
+// @Filename: /c.js
+////const a = require("./a");
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export default 0;`,
+});
+
+goTo.file("/b.ts");
+verify.currentFileContentIs('import a from "./a";');
+
+goTo.file("/c.js");
+verify.currentFileContentIs('const a = require("./a").default;');

tests/cases/fourslash/refactorConvertToEs6Module_export_named.ts

@@ -0,0 +1,19 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/exports/*b*/.f = function() {}
+////exports.C = class {}
+////exports.x = 0;
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export function f() { }
+export class C {
+}
+export const x = 0;`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_object.ts

@@ -0,0 +1,25 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/module/*b*/.exports = {
+////    x: 0,
+////    f: function() {},
+////    g: () => {},
+////    h() {},
+////    C: class {},
+////};
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export const x = 0;
+export function f() { }
+export function g() { }
+export function h() { }
+export class C {
+}`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_object_shorthand.ts

@@ -0,0 +1,18 @@
+/// <reference path='fourslash.ts' />
+
+// TODO: Maybe we could transform this to `export function f() {}`.
+
+// @allowJs: true
+
+// @Filename: /a.js
+////function f() {}
+/////*a*/module/*b*/.exports = { f };
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `function f() {}
+export default { f };`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_export_referenced.ts

@@ -0,0 +1,36 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+////exports.x = 0;
+////exports.x;
+////
+////const y = 1;
+/////*a*/exports/*b*/.y = y;
+////exports.y;
+////
+////exports.z = 2;
+////function f(z) {
+////    exports.z;
+////}
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export const x = 0;
+x;
+
+const y = 1;
+const _y = y;
+export { _y as y };
+_y;
+
+const _z = 2;
+export { _z as z };
+function f(z) {
+    _z;
+}`,
+});

tests/cases/fourslash/refactorConvertToEs6Module_expressionToDeclaration.ts

@@ -0,0 +1,18 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*a*/exports/*b*/.f = async function* f(p) {}
+////exports.C = class C extends D { m() {} }
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Convert to ES6 module",
+    actionName: "Convert to ES6 module",
+    actionDescription: "Convert to ES6 module",
+    newContent: `export async function* f(p) { }
+export class C extends D {
+    m() { }
+}`,
+});