Merge pull request #9692 from Microsoft/fix-emit-with-this-and-rest-parameters

Fix emit with this and rest parameters

Author: sandersn

src/compiler/emitter.ts

@@ -4571,14 +4571,15 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 
             function emitRestParameter(node: FunctionLikeDeclaration) {
                 if (languageVersion < ScriptTarget.ES6 && hasDeclaredRestParameter(node)) {
-                    const restIndex = node.parameters.length - 1;
-                    const restParam = node.parameters[restIndex];
+                    const restParam = node.parameters[node.parameters.length - 1];
 
                     // A rest parameter cannot have a binding pattern, so let's just ignore it if it does.
                     if (isBindingPattern(restParam.name)) {
                         return;
                     }
 
+                    const skipThisCount = node.parameters.length && (<Identifier>node.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword ? 1 : 0;
+                    const restIndex = node.parameters.length - 1 - skipThisCount;
                     const tempName = createTempVariable(TempFlags._i).text;
                     writeLine();
                     emitLeadingComments(restParam);
@@ -4726,7 +4727,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                 write("(");
                 if (node) {
                     const parameters = node.parameters;
-                    const skipCount = node.parameters.length && (<Identifier>node.parameters[0].name).text === "this" ? 1 : 0;
+                    const skipCount = node.parameters.length && (<Identifier>node.parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword ? 1 : 0;
                     const omitCount = languageVersion < ScriptTarget.ES6 && hasDeclaredRestParameter(node) ? 1 : 0;
                     emitList(parameters, skipCount, parameters.length - omitCount - skipCount, /*multiLine*/ false, /*trailingComma*/ false);
                 }
@@ -6156,10 +6157,11 @@ const _super = (function (geti, seti) {
 
                     if (valueDeclaration) {
                         const parameters = valueDeclaration.parameters;
+                        const skipThisCount = parameters.length && (<Identifier>parameters[0].name).originalKeywordKind === SyntaxKind.ThisKeyword ? 1 : 0;
                         const parameterCount = parameters.length;
-                        if (parameterCount > 0) {
-                            for (let i = 0; i < parameterCount; i++) {
-                                if (i > 0) {
+                        if (parameterCount > skipThisCount) {
+                            for (let i = skipThisCount; i < parameterCount; i++) {
+                                if (i > skipThisCount) {
                                     write(", ");
                                 }
 

tests/baselines/reference/emitDecoratorMetadata_restArgs.js

@@ -14,7 +14,7 @@ class A {
 class B {
     constructor(...args: number[]) {}
     @MyMethodDecorator
-    method(...args: string[]) {}
+    method(this: this, ...args: string[]) {}
 }
 
 

tests/baselines/reference/emitDecoratorMetadata_restArgs.symbols

@@ -37,8 +37,9 @@ class B {
     @MyMethodDecorator
 >MyMethodDecorator : Symbol(MyMethodDecorator, Decl(emitDecoratorMetadata_restArgs.ts, 2, 13))
 
-    method(...args: string[]) {}
+    method(this: this, ...args: string[]) {}
 >method : Symbol(B.method, Decl(emitDecoratorMetadata_restArgs.ts, 13, 37))
->args : Symbol(args, Decl(emitDecoratorMetadata_restArgs.ts, 15, 11))
+>this : Symbol(this, Decl(emitDecoratorMetadata_restArgs.ts, 15, 11))
+>args : Symbol(args, Decl(emitDecoratorMetadata_restArgs.ts, 15, 22))
 }
 

tests/baselines/reference/emitDecoratorMetadata_restArgs.types

@@ -37,8 +37,9 @@ class B {
     @MyMethodDecorator
 >MyMethodDecorator : <T>(target: Object, propertyKey: string | symbol, descriptor: TypedPropertyDescriptor<T>) => TypedPropertyDescriptor<T> | void
 
-    method(...args: string[]) {}
->method : (...args: string[]) => void
+    method(this: this, ...args: string[]) {}
+>method : (this: this, ...args: string[]) => void
+>this : this
 >args : string[]
 }
 

tests/baselines/reference/emitSkipsThisWithRestParameter.js

@@ -0,0 +1,18 @@
+//// [emitSkipsThisWithRestParameter.ts]
+function rebase(fn: (base: any, ...args: any[]) => any): (...args: any[]) => any {
+    return function(this: any, ...args: any[]) {
+        return fn.apply(this, [ this ].concat(args));
+    };
+}
+
+
+//// [emitSkipsThisWithRestParameter.js]
+function rebase(fn) {
+    return function () {
+        var args = [];
+        for (var _i = 0; _i < arguments.length; _i++) {
+            args[_i - 0] = arguments[_i];
+        }
+        return fn.apply(this, [this].concat(args));
+    };
+}

tests/baselines/reference/emitSkipsThisWithRestParameter.symbols

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/emitSkipsThisWithRestParameter.ts ===
+function rebase(fn: (base: any, ...args: any[]) => any): (...args: any[]) => any {
+>rebase : Symbol(rebase, Decl(emitSkipsThisWithRestParameter.ts, 0, 0))
+>fn : Symbol(fn, Decl(emitSkipsThisWithRestParameter.ts, 0, 16))
+>base : Symbol(base, Decl(emitSkipsThisWithRestParameter.ts, 0, 21))
+>args : Symbol(args, Decl(emitSkipsThisWithRestParameter.ts, 0, 31))
+>args : Symbol(args, Decl(emitSkipsThisWithRestParameter.ts, 0, 58))
+
+    return function(this: any, ...args: any[]) {
+>this : Symbol(this, Decl(emitSkipsThisWithRestParameter.ts, 1, 20))
+>args : Symbol(args, Decl(emitSkipsThisWithRestParameter.ts, 1, 30))
+
+        return fn.apply(this, [ this ].concat(args));
+>fn.apply : Symbol(Function.apply, Decl(lib.d.ts, --, --))
+>fn : Symbol(fn, Decl(emitSkipsThisWithRestParameter.ts, 0, 16))
+>apply : Symbol(Function.apply, Decl(lib.d.ts, --, --))
+>this : Symbol(this, Decl(emitSkipsThisWithRestParameter.ts, 1, 20))
+>[ this ].concat : Symbol(Array.concat, Decl(lib.d.ts, --, --))
+>this : Symbol(this, Decl(emitSkipsThisWithRestParameter.ts, 1, 20))
+>concat : Symbol(Array.concat, Decl(lib.d.ts, --, --))
+>args : Symbol(args, Decl(emitSkipsThisWithRestParameter.ts, 1, 30))
+
+    };
+}
+

tests/baselines/reference/emitSkipsThisWithRestParameter.types

@@ -0,0 +1,29 @@
+=== tests/cases/compiler/emitSkipsThisWithRestParameter.ts ===
+function rebase(fn: (base: any, ...args: any[]) => any): (...args: any[]) => any {
+>rebase : (fn: (base: any, ...args: any[]) => any) => (...args: any[]) => any
+>fn : (base: any, ...args: any[]) => any
+>base : any
+>args : any[]
+>args : any[]
+
+    return function(this: any, ...args: any[]) {
+>function(this: any, ...args: any[]) {        return fn.apply(this, [ this ].concat(args));    } : (this: any, ...args: any[]) => any
+>this : any
+>args : any[]
+
+        return fn.apply(this, [ this ].concat(args));
+>fn.apply(this, [ this ].concat(args)) : any
+>fn.apply : (this: Function, thisArg: any, argArray?: any) => any
+>fn : (base: any, ...args: any[]) => any
+>apply : (this: Function, thisArg: any, argArray?: any) => any
+>this : any
+>[ this ].concat(args) : any[]
+>[ this ].concat : (...items: any[]) => any[]
+>[ this ] : any[]
+>this : any
+>concat : (...items: any[]) => any[]
+>args : any[]
+
+    };
+}
+

tests/cases/compiler/emitDecoratorMetadata_restArgs.ts

@@ -16,5 +16,5 @@ class A {
 class B {
     constructor(...args: number[]) {}
     @MyMethodDecorator
-    method(...args: string[]) {}
+    method(this: this, ...args: string[]) {}
 }

tests/cases/compiler/emitSkipsThisWithRestParameter.ts

@@ -0,0 +1,5 @@
+function rebase(fn: (base: any, ...args: any[]) => any): (...args: any[]) => any {
+    return function(this: any, ...args: any[]) {
+        return fn.apply(this, [ this ].concat(args));
+    };
+}