Import helpers skips __assign when target >= ES6

sandersn · sandersn · commit cca68adf877f · 2017-01-30T12:42:19.000-08:00
Instead, Object.assign is emitted.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -11721,7 +11721,7 @@ namespace ts {
                     member = prop;
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
-                    if (languageVersion < ScriptTarget.ESNext) {
+                    if (languageVersion < ScriptTarget.ES2015) {
                         checkExternalEmitHelpers(memberDecl, ExternalEmitHelpers.Assign);
                     }
                     if (propertiesArray.length > 0) {
diff --git a/tests/baselines/reference/importHelpersES6.js b/tests/baselines/reference/importHelpersES6.js
@@ -5,10 +5,12 @@ declare var dec: any;
 @dec export class A {
 
 }
+
+const o = { a: 1 };
+const y = { ...o };
 
 //// [tslib.d.ts]
 export declare function __extends(d: Function, b: Function): void;
-export declare function __assign(t: any, ...sources: any[]): any;
 export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;
 export declare function __param(paramIndex: number, decorator: Function): Function;
 export declare function __metadata(metadataKey: any, metadataValue: any): Function;
@@ -23,3 +25,5 @@ A = tslib_1.__decorate([
     dec
 ], A);
 export { A };
+const o = { a: 1 };
+const y = Object.assign({}, o);
diff --git a/tests/baselines/reference/importHelpersES6.symbols b/tests/baselines/reference/importHelpersES6.symbols
@@ -8,6 +8,14 @@ declare var dec: any;
 
 }
 
+const o = { a: 1 };
+>o : Symbol(o, Decl(a.ts, 5, 5))
+>a : Symbol(a, Decl(a.ts, 5, 11))
+
+const y = { ...o };
+>y : Symbol(y, Decl(a.ts, 6, 5))
+>o : Symbol(o, Decl(a.ts, 5, 5))
+
 === tests/cases/compiler/tslib.d.ts ===
 export declare function __extends(d: Function, b: Function): void;
 >__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
@@ -16,11 +24,6 @@ export declare function __extends(d: Function, b: Function): void;
 >b : Symbol(b, Decl(tslib.d.ts, --, --))
 >Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
 
-export declare function __assign(t: any, ...sources: any[]): any;
->__assign : Symbol(__assign, Decl(tslib.d.ts, --, --))
->t : Symbol(t, Decl(tslib.d.ts, --, --))
->sources : Symbol(sources, Decl(tslib.d.ts, --, --))
-
 export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;
 >__decorate : Symbol(__decorate, Decl(tslib.d.ts, --, --))
 >decorators : Symbol(decorators, Decl(tslib.d.ts, --, --))
diff --git a/tests/baselines/reference/importHelpersES6.types b/tests/baselines/reference/importHelpersES6.types
@@ -8,6 +8,17 @@ declare var dec: any;
 
 }
 
+const o = { a: 1 };
+>o : { a: number; }
+>{ a: 1 } : { a: number; }
+>a : number
+>1 : 1
+
+const y = { ...o };
+>y : { a: number; }
+>{ ...o } : { a: number; }
+>o : { a: number; }
+
 === tests/cases/compiler/tslib.d.ts ===
 export declare function __extends(d: Function, b: Function): void;
 >__extends : (d: Function, b: Function) => void
@@ -16,11 +27,6 @@ export declare function __extends(d: Function, b: Function): void;
 >b : Function
 >Function : Function
 
-export declare function __assign(t: any, ...sources: any[]): any;
->__assign : (t: any, ...sources: any[]) => any
->t : any
->sources : any[]
-
 export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;
 >__decorate : (decorators: Function[], target: any, key?: string | symbol, desc?: any) => any
 >decorators : Function[]
diff --git a/tests/cases/compiler/importHelpersES6.ts b/tests/cases/compiler/importHelpersES6.ts
@@ -7,9 +7,11 @@ declare var dec: any;
 
 }
 
+const o = { a: 1 };
+const y = { ...o };
+
 // @filename: tslib.d.ts
 export declare function __extends(d: Function, b: Function): void;
-export declare function __assign(t: any, ...sources: any[]): any;
 export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;
 export declare function __param(paramIndex: number, decorator: Function): Function;
 export declare function __metadata(metadataKey: any, metadataValue: any): Function;

Original file line number	Diff line number	Diff line change
`@@ -11721,7 +11721,7 @@ namespace ts {`
`11721`	`11721`	`member = prop;`
`11722`	`11722`	`}`
`11723`	`11723`	`else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {`
`11724`		`- if (languageVersion < ScriptTarget.ESNext) {`
	`11724`	`+ if (languageVersion < ScriptTarget.ES2015) {`
`11725`	`11725`	`checkExternalEmitHelpers(memberDecl, ExternalEmitHelpers.Assign);`
`11726`	`11726`	`}`
`11727`	`11727`	`if (propertiesArray.length > 0) {`