Merge branch 'master' into fixInstanceOfFunction

Author: ahejlsberg

.github/ISSUE_TEMPLATE/Bug_report.md

@@ -16,7 +16,7 @@ Please fill in the *entire* template below.
 -->
 
 <!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. -->
-**TypeScript Version:**  3.1.0-dev.201xxxxx
+**TypeScript Version:**  3.2.0-dev.201xxxxx
 
 <!-- Search terms you tried before logging this (so others can find this issue more easily) -->
 **Search Terms:**

package.json

@@ -2,7 +2,7 @@
     "name": "typescript",
     "author": "Microsoft Corp.",
     "homepage": "http://typescriptlang.org/",
-    "version": "3.1.0",
+    "version": "3.2.0",
     "license": "Apache-2.0",
     "description": "TypeScript is a language for application scale JavaScript development",
     "keywords": [

src/compiler/checker.ts

@@ -77,6 +77,7 @@ namespace ts {
         const allowSyntheticDefaultImports = getAllowSyntheticDefaultImports(compilerOptions);
         const strictNullChecks = getStrictOptionValue(compilerOptions, "strictNullChecks");
         const strictFunctionTypes = getStrictOptionValue(compilerOptions, "strictFunctionTypes");
+        const strictBindCallApply = getStrictOptionValue(compilerOptions, "strictBindCallApply");
         const strictPropertyInitialization = getStrictOptionValue(compilerOptions, "strictPropertyInitialization");
         const noImplicitAny = getStrictOptionValue(compilerOptions, "noImplicitAny");
         const noImplicitThis = getStrictOptionValue(compilerOptions, "noImplicitThis");
@@ -476,6 +477,8 @@ namespace ts {
 
         let globalObjectType: ObjectType;
         let globalFunctionType: ObjectType;
+        let globalCallableFunctionType: ObjectType;
+        let globalNewableFunctionType: ObjectType;
         let globalArrayType: GenericType;
         let globalReadonlyArrayType: GenericType;
         let globalStringType: ObjectType;
@@ -1708,7 +1711,9 @@ namespace ts {
         function checkResolvedBlockScopedVariable(result: Symbol, errorLocation: Node): void {
             Debug.assert(!!(result.flags & SymbolFlags.BlockScopedVariable || result.flags & SymbolFlags.Class || result.flags & SymbolFlags.Enum));
             // Block-scoped variables cannot be used before their definition
-            const declaration = forEach(result.declarations, d => isBlockOrCatchScoped(d) || isClassLike(d) || (d.kind === SyntaxKind.EnumDeclaration) ? d : undefined);
+            const declaration = find(
+                result.declarations,
+                d => isBlockOrCatchScoped(d) || isClassLike(d) || (d.kind === SyntaxKind.EnumDeclaration) || isInJSFile(d) && !!getJSDocEnumTag(d));
 
             if (declaration === undefined) return Debug.fail("Declaration to checkResolvedBlockScopedVariable is undefined");
 
@@ -7391,8 +7396,12 @@ namespace ts {
                 if (symbol && symbolIsValue(symbol)) {
                     return symbol;
                 }
-                if (resolved === anyFunctionType || resolved.callSignatures.length || resolved.constructSignatures.length) {
-                    const symbol = getPropertyOfObjectType(globalFunctionType, name);
+                const functionType = resolved === anyFunctionType ? globalFunctionType :
+                    resolved.callSignatures.length ? globalCallableFunctionType :
+                    resolved.constructSignatures.length ? globalNewableFunctionType :
+                    undefined;
+                if (functionType) {
+                    const symbol = getPropertyOfObjectType(functionType, name);
                     if (symbol) {
                         return symbol;
                     }
@@ -13250,10 +13259,8 @@ namespace ts {
             const targetCount = getParameterCount(target);
             const sourceRestType = getEffectiveRestType(source);
             const targetRestType = getEffectiveRestType(target);
-            const paramCount = targetRestType ? Math.min(targetCount - 1, sourceCount) :
-                sourceRestType ? targetCount :
-                Math.min(sourceCount, targetCount);
-
+            const targetNonRestCount = targetRestType ? targetCount - 1 : targetCount;
+            const paramCount = sourceRestType ? targetNonRestCount : Math.min(sourceCount, targetNonRestCount);
             const sourceThisType = getThisTypeOfSignature(source);
             if (sourceThisType) {
                 const targetThisType = getThisTypeOfSignature(target);
@@ -13900,15 +13907,17 @@ namespace ts {
             if (!inferredType) {
                 const signature = context.signature;
                 if (signature) {
-                    if (inference.contraCandidates && (!inference.candidates || inference.candidates.length === 1 && inference.candidates[0].flags & TypeFlags.Never)) {
-                        // If we have contravariant inferences, but no covariant inferences or a single
-                        // covariant inference of 'never', we find the best common subtype and treat that
-                        // as a single covariant candidate.
-                        inference.candidates = [getContravariantInference(inference)];
-                        inference.contraCandidates = undefined;
-                    }
-                    if (inference.candidates) {
-                        inferredType = getCovariantInference(inference, signature);
+                    const inferredCovariantType = inference.candidates ? getCovariantInference(inference, signature) : undefined;
+                    if (inference.contraCandidates) {
+                        const inferredContravariantType = getContravariantInference(inference);
+                        // If we have both co- and contra-variant inferences, we prefer the contra-variant inference
+                        // unless the co-variant inference is a subtype and not 'never'.
+                        inferredType = inferredCovariantType && !(inferredCovariantType.flags & TypeFlags.Never) &&
+                            isTypeSubtypeOf(inferredCovariantType, inferredContravariantType) ?
+                            inferredCovariantType : inferredContravariantType;
+                    }
+                    else if (inferredCovariantType) {
+                        inferredType = inferredCovariantType;
                     }
                     else if (context.flags & InferenceFlags.NoDefault) {
                         // We use silentNeverType as the wildcard that signals no inferences.
@@ -19684,7 +19693,10 @@ namespace ts {
                         checkCandidate = candidate;
                     }
                     if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /*reportErrors*/ false)) {
-                        candidateForArgumentError = checkCandidate;
+                        // Give preference to error candidates that have no rest parameters (as they are more specific)
+                        if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
+                            candidateForArgumentError = checkCandidate;
+                        }
                         continue;
                     }
                     if (excludeArgument) {
@@ -19697,7 +19709,10 @@ namespace ts {
                             checkCandidate = getSignatureInstantiation(candidate, typeArgumentTypes, isInJSFile(candidate.declaration));
                         }
                         if (!checkApplicableSignature(node, args, checkCandidate, relation, excludeArgument, /*reportErrors*/ false)) {
-                            candidateForArgumentError = checkCandidate;
+                            // Give preference to error candidates that have no rest parameters (as they are more specific)
+                            if (!candidateForArgumentError || getEffectiveRestType(candidateForArgumentError) || !getEffectiveRestType(checkCandidate)) {
+                                candidateForArgumentError = checkCandidate;
+                            }
                             continue;
                         }
                     }
@@ -28029,8 +28044,11 @@ namespace ts {
         function getAugmentedPropertiesOfType(type: Type): Symbol[] {
             type = getApparentType(type);
             const propsByName = createSymbolTable(getPropertiesOfType(type));
-            if (typeHasCallOrConstructSignatures(type)) {
-                forEach(getPropertiesOfType(globalFunctionType), p => {
+            const functionType = getSignaturesOfType(type, SignatureKind.Call).length ? globalCallableFunctionType :
+                getSignaturesOfType(type, SignatureKind.Construct).length ? globalNewableFunctionType :
+                undefined;
+            if (functionType) {
+                forEach(getPropertiesOfType(functionType), p => {
                     if (!propsByName.has(p.escapedName)) {
                         propsByName.set(p.escapedName, p);
                     }
@@ -28810,6 +28828,8 @@ namespace ts {
             globalArrayType = getGlobalType("Array" as __String, /*arity*/ 1, /*reportErrors*/ true);
             globalObjectType = getGlobalType("Object" as __String, /*arity*/ 0, /*reportErrors*/ true);
             globalFunctionType = getGlobalType("Function" as __String, /*arity*/ 0, /*reportErrors*/ true);
+            globalCallableFunctionType = strictBindCallApply && getGlobalType("CallableFunction" as __String, /*arity*/ 0, /*reportErrors*/ true) || globalFunctionType;
+            globalNewableFunctionType = strictBindCallApply && getGlobalType("NewableFunction" as __String, /*arity*/ 0, /*reportErrors*/ true) || globalFunctionType;
             globalStringType = getGlobalType("String" as __String, /*arity*/ 0, /*reportErrors*/ true);
             globalNumberType = getGlobalType("Number" as __String, /*arity*/ 0, /*reportErrors*/ true);
             globalBooleanType = getGlobalType("Boolean" as __String, /*arity*/ 0, /*reportErrors*/ true);

src/compiler/commandLineParser.ts

@@ -373,6 +373,14 @@ namespace ts {
             category: Diagnostics.Strict_Type_Checking_Options,
             description: Diagnostics.Enable_strict_checking_of_function_types
         },
+        {
+            name: "strictBindCallApply",
+            type: "boolean",
+            strictFlag: true,
+            showInSimplifiedHelpView: true,
+            category: Diagnostics.Strict_Type_Checking_Options,
+            description: Diagnostics.Enable_strict_bind_call_and_apply_methods_on_functions
+        },
         {
             name: "strictPropertyInitialization",
             type: "boolean",

src/compiler/core.ts

@@ -1,7 +1,7 @@
 namespace ts {
     // WARNING: The script `configureNightly.ts` uses a regexp to parse out these values.
     // If changing the text in this section, be sure to test `configureNightly` too.
-    export const versionMajorMinor = "3.1";
+    export const versionMajorMinor = "3.2";
     /** The version of the TypeScript compiler release */
     export const version = `${versionMajorMinor}.0-dev`;
 }

src/compiler/diagnosticMessages.json

@@ -3759,6 +3759,10 @@
         "category": "Message",
         "code": 6213
     },
+    "Enable strict 'bind', 'call', and 'apply' methods on functions.": {
+        "category": "Message",
+        "code": 6214
+    },
 
     "Projects to reference": {
         "category": "Message",

src/compiler/types.ts

@@ -4427,6 +4427,7 @@ namespace ts {
         sourceRoot?: string;
         strict?: boolean;
         strictFunctionTypes?: boolean;  // Always combine with strict property
+        strictBindCallApply?: boolean;  // Always combine with strict property
         strictNullChecks?: boolean;  // Always combine with strict property
         strictPropertyInitialization?: boolean;  // Always combine with strict property
         stripInternal?: boolean;

src/compiler/utilities.ts

@@ -7085,7 +7085,7 @@ namespace ts {
         return !!(compilerOptions.declaration || compilerOptions.composite);
     }
 
-    export type StrictOptionName = "noImplicitAny" | "noImplicitThis" | "strictNullChecks" | "strictFunctionTypes" | "strictPropertyInitialization" | "alwaysStrict";
+    export type StrictOptionName = "noImplicitAny" | "noImplicitThis" | "strictNullChecks" | "strictFunctionTypes" | "strictBindCallApply" | "strictPropertyInitialization" | "alwaysStrict";
 
     export function getStrictOptionValue(compilerOptions: CompilerOptions, flag: StrictOptionName): boolean {
         return compilerOptions[flag] === undefined ? !!compilerOptions.strict : !!compilerOptions[flag];

src/harness/virtualFileSystemWithWatch.ts

@@ -4,6 +4,8 @@ namespace ts.TestFSWithWatch {
         content: `/// <reference no-default-lib="true"/>
 interface Boolean {}
 interface Function {}
+interface CallableFunction {}
+interface NewableFunction {}
 interface IArguments {}
 interface Number { toExponential: any; }
 interface Object {}

src/lib/es5.d.ts

@@ -295,6 +295,66 @@ interface FunctionConstructor {
 
 declare const Function: FunctionConstructor;
 
+interface CallableFunction extends Function {
+    /**
+      * Calls the function with the specified object as the this value and the elements of specified array as the arguments.
+      * @param thisArg The object to be used as the this object.
+      * @param args An array of argument values to be passed to the function.
+      */
+    apply<T, R>(this: (this: T) => R, thisArg: T): R;
+    apply<T, A extends any[], R>(this: (this: T, ...args: A) => R, thisArg: T, args: A): R;
+
+    /**
+      * Calls the function with the specified object as the this value and the specified rest arguments as the arguments.
+      * @param thisArg The object to be used as the this object.
+      * @param args Argument values to be passed to the function.
+      */
+    call<T, A extends any[], R>(this: (this: T, ...args: A) => R, thisArg: T, ...args: A): R;
+
+    /**
+      * For a given function, creates a bound function that has the same body as the original function.
+      * The this object of the bound function is associated with the specified object, and has the specified initial parameters.
+      * @param thisArg The object to be used as the this object.
+      * @param args Arguments to bind to the parameters of the function.
+      */
+    bind<T, A extends any[], R>(this: (this: T, ...args: A) => R, thisArg: T): (...args: A) => R;
+    bind<T, A0, A extends any[], R>(this: (this: T, arg0: A0, ...args: A) => R, thisArg: T, arg0: A0): (...args: A) => R;
+    bind<T, A0, A1, A extends any[], R>(this: (this: T, arg0: A0, arg1: A1, ...args: A) => R, thisArg: T, arg0: A0, arg1: A1): (...args: A) => R;
+    bind<T, A0, A1, A2, A extends any[], R>(this: (this: T, arg0: A0, arg1: A1, arg2: A2, ...args: A) => R, thisArg: T, arg0: A0, arg1: A1, arg2: A2): (...args: A) => R;
+    bind<T, A0, A1, A2, A3, A extends any[], R>(this: (this: T, arg0: A0, arg1: A1, arg2: A2, arg3: A3, ...args: A) => R, thisArg: T, arg0: A0, arg1: A1, arg2: A2, arg3: A3): (...args: A) => R;
+    bind<T, AX, R>(this: (this: T, ...args: AX[]) => R, thisArg: T, ...args: AX[]): (...args: AX[]) => R;
+}
+
+interface NewableFunction extends Function {
+    /**
+      * Calls the function with the specified object as the this value and the elements of specified array as the arguments.
+      * @param thisArg The object to be used as the this object.
+      * @param args An array of argument values to be passed to the function.
+      */
+    apply<T>(this: new () => T, thisArg: T): void;
+    apply<T, A extends any[]>(this: new (...args: A) => T, thisArg: T, args: A): void;
+
+    /**
+      * Calls the function with the specified object as the this value and the specified rest arguments as the arguments.
+      * @param thisArg The object to be used as the this object.
+      * @param args Argument values to be passed to the function.
+      */
+    call<T, A extends any[]>(this: new (...args: A) => T, thisArg: T, ...args: A): void;
+
+    /**
+      * For a given function, creates a bound function that has the same body as the original function.
+      * The this object of the bound function is associated with the specified object, and has the specified initial parameters.
+      * @param thisArg The object to be used as the this object.
+      * @param args Arguments to bind to the parameters of the function.
+      */
+    bind<A extends any[], R>(this: new (...args: A) => R, thisArg: any): new (...args: A) => R;
+    bind<A0, A extends any[], R>(this: new (arg0: A0, ...args: A) => R, thisArg: any, arg0: A0): new (...args: A) => R;
+    bind<A0, A1, A extends any[], R>(this: new (arg0: A0, arg1: A1, ...args: A) => R, thisArg: any, arg0: A0, arg1: A1): new (...args: A) => R;
+    bind<A0, A1, A2, A extends any[], R>(this: new (arg0: A0, arg1: A1, arg2: A2, ...args: A) => R, thisArg: any, arg0: A0, arg1: A1, arg2: A2): new (...args: A) => R;
+    bind<A0, A1, A2, A3, A extends any[], R>(this: new (arg0: A0, arg1: A1, arg2: A2, arg3: A3, ...args: A) => R, thisArg: any, arg0: A0, arg1: A1, arg2: A2, arg3: A3): new (...args: A) => R;
+    bind<AX, R>(this: new (...args: AX[]) => R, thisArg: any, ...args: AX[]): new (...args: AX[]) => R;
+}
+
 interface IArguments {
     [index: number]: any;
     length: number;