diff --git a/tests/baselines/reference/importHelpers.js b/tests/baselines/reference/importHelpers.js
index 52e07fb98bb..f850b5cf177 100644
--- a/tests/baselines/reference/importHelpers.js
+++ b/tests/baselines/reference/importHelpers.js
@@ -22,7 +22,16 @@ declare var dec: any;
 class C {
     method(@dec x: number) {
     }
-}
+}
+
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [external.js]
 "use strict";
diff --git a/tests/baselines/reference/importHelpers.symbols b/tests/baselines/reference/importHelpers.symbols
index cb852ab286c..55ca5153e32 100644
--- a/tests/baselines/reference/importHelpers.symbols
+++ b/tests/baselines/reference/importHelpers.symbols
@@ -45,3 +45,47 @@ class C {
 >x : Symbol(x, Decl(script.ts, 7, 11))
     }
 }
+
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.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, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>generator : Symbol(generator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/importHelpers.types b/tests/baselines/reference/importHelpers.types
index 0d1cda653e8..0ab8d40ee85 100644
--- a/tests/baselines/reference/importHelpers.types
+++ b/tests/baselines/reference/importHelpers.types
@@ -45,3 +45,47 @@ class C {
 >x : number
     }
 }
+
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/baselines/reference/importHelpersAmd.js b/tests/baselines/reference/importHelpersAmd.js
index e5f6bdce278..bb02cbf0417 100644
--- a/tests/baselines/reference/importHelpersAmd.js
+++ b/tests/baselines/reference/importHelpersAmd.js
@@ -1,11 +1,20 @@
 //// [tests/cases/compiler/importHelpersAmd.ts] ////
 
 //// [a.ts]
-export class A { }
+export class A { }
+
 //// [b.ts]
 import { A } from "./a";
 export class B extends A { }
 
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [a.js]
 define(["require", "exports"], function (require, exports) {
diff --git a/tests/baselines/reference/importHelpersAmd.symbols b/tests/baselines/reference/importHelpersAmd.symbols
index d4155c4bf52..47528a8bba6 100644
--- a/tests/baselines/reference/importHelpersAmd.symbols
+++ b/tests/baselines/reference/importHelpersAmd.symbols
@@ -10,3 +10,46 @@ export class B extends A { }
 >B : Symbol(B, Decl(b.ts, 0, 24))
 >A : Symbol(A, Decl(b.ts, 0, 8))
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.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, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>generator : Symbol(generator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/importHelpersAmd.types b/tests/baselines/reference/importHelpersAmd.types
index 7f313d87cd6..9ff756ffaab 100644
--- a/tests/baselines/reference/importHelpersAmd.types
+++ b/tests/baselines/reference/importHelpersAmd.types
@@ -10,3 +10,46 @@ export class B extends A { }
 >B : B
 >A : A
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/baselines/reference/importHelpersES6.js b/tests/baselines/reference/importHelpersES6.js
index c9709986853..209f3c34588 100644
--- a/tests/baselines/reference/importHelpersES6.js
+++ b/tests/baselines/reference/importHelpersES6.js
@@ -1,8 +1,19 @@
+//// [tests/cases/compiler/importHelpersES6.ts] ////
+
 //// [a.ts]
 declare var dec: any;
 @dec export class A {
 
-}
+}
+
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [a.js]
 import * as tslib_1 from "tslib";
diff --git a/tests/baselines/reference/importHelpersES6.symbols b/tests/baselines/reference/importHelpersES6.symbols
index 66d3cd62c41..284a2251a6b 100644
--- a/tests/baselines/reference/importHelpersES6.symbols
+++ b/tests/baselines/reference/importHelpersES6.symbols
@@ -7,3 +7,47 @@ declare var dec: any;
 >A : Symbol(A, Decl(a.ts, 0, 21))
 
 }
+
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, 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, --, --))
+>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, --, --))
+>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, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, 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, --, --))
+>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 __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, 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 __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, 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, --, --))
+>generator : Symbol(generator, 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, --, --))
+
diff --git a/tests/baselines/reference/importHelpersES6.types b/tests/baselines/reference/importHelpersES6.types
index d54a768ea7f..ebfd5a5a2a5 100644
--- a/tests/baselines/reference/importHelpersES6.types
+++ b/tests/baselines/reference/importHelpersES6.types
@@ -7,3 +7,47 @@ declare var dec: any;
 >A : A
 
 }
+
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/baselines/reference/importHelpersInIsolatedModules.errors.txt b/tests/baselines/reference/importHelpersInIsolatedModules.errors.txt
index 9005078fada..7a53c1c8c99 100644
--- a/tests/baselines/reference/importHelpersInIsolatedModules.errors.txt
+++ b/tests/baselines/reference/importHelpersInIsolatedModules.errors.txt
@@ -25,4 +25,13 @@ tests/cases/compiler/script.ts(1,1): error TS1208: Cannot compile namespaces whe
     class C {
         method(@dec x: number) {
         }
-    }
\ No newline at end of file
+    }
+    
+==== tests/cases/compiler/tslib.d.ts (0 errors) ====
+    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;
+    export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/importHelpersInIsolatedModules.js b/tests/baselines/reference/importHelpersInIsolatedModules.js
index f9aa4cfa1b9..a5929bc152c 100644
--- a/tests/baselines/reference/importHelpersInIsolatedModules.js
+++ b/tests/baselines/reference/importHelpersInIsolatedModules.js
@@ -22,7 +22,16 @@ declare var dec: any;
 class C {
     method(@dec x: number) {
     }
-}
+}
+
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [external.js]
 "use strict";
diff --git a/tests/baselines/reference/importHelpersInTsx.js b/tests/baselines/reference/importHelpersInTsx.js
index 2d0ae56793f..29e43e191e8 100644
--- a/tests/baselines/reference/importHelpersInTsx.js
+++ b/tests/baselines/reference/importHelpersInTsx.js
@@ -5,16 +5,25 @@ declare var React: any;
 declare var o: any;
 export const x = <span {...o} />
 
-//// [internal.tsx]
+//// [script.tsx]
 declare var React: any;
 declare var o: any;
-const x = <span {...o} />
+const x = <span {...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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [external.js]
 "use strict";
 var tslib_1 = require("tslib");
 exports.x = React.createElement("span", tslib_1.__assign({}, o));
-//// [internal.js]
+//// [script.js]
 var __assign = (this && this.__assign) || Object.assign || function(t) {
     for (var s, i = 1, n = arguments.length; i < n; i++) {
         s = arguments[i];
diff --git a/tests/baselines/reference/importHelpersInTsx.symbols b/tests/baselines/reference/importHelpersInTsx.symbols
index 16ca20e0fe4..465ce502385 100644
--- a/tests/baselines/reference/importHelpersInTsx.symbols
+++ b/tests/baselines/reference/importHelpersInTsx.symbols
@@ -10,15 +10,58 @@ export const x = <span {...o} />
 >span : Symbol(unknown)
 >o : Symbol(o, Decl(external.tsx, 1, 11))
 
-=== tests/cases/compiler/internal.tsx ===
+=== tests/cases/compiler/script.tsx ===
 declare var React: any;
->React : Symbol(React, Decl(internal.tsx, 0, 11))
+>React : Symbol(React, Decl(script.tsx, 0, 11))
 
 declare var o: any;
->o : Symbol(o, Decl(internal.tsx, 1, 11))
+>o : Symbol(o, Decl(script.tsx, 1, 11))
 
 const x = <span {...o} />
->x : Symbol(x, Decl(internal.tsx, 2, 5))
+>x : Symbol(x, Decl(script.tsx, 2, 5))
 >span : Symbol(unknown)
->o : Symbol(o, Decl(internal.tsx, 1, 11))
+>o : Symbol(o, Decl(script.tsx, 1, 11))
+
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.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, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>generator : Symbol(generator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
 
diff --git a/tests/baselines/reference/importHelpersInTsx.types b/tests/baselines/reference/importHelpersInTsx.types
index 2e833e78c19..a6ae6e95f86 100644
--- a/tests/baselines/reference/importHelpersInTsx.types
+++ b/tests/baselines/reference/importHelpersInTsx.types
@@ -11,7 +11,7 @@ export const x = <span {...o} />
 >span : any
 >o : any
 
-=== tests/cases/compiler/internal.tsx ===
+=== tests/cases/compiler/script.tsx ===
 declare var React: any;
 >React : any
 
@@ -24,3 +24,46 @@ const x = <span {...o} />
 >span : any
 >o : any
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/baselines/reference/importHelpersNoHelpers.errors.txt b/tests/baselines/reference/importHelpersNoHelpers.errors.txt
new file mode 100644
index 00000000000..ebb25dbd7c9
--- /dev/null
+++ b/tests/baselines/reference/importHelpersNoHelpers.errors.txt
@@ -0,0 +1,36 @@
+error TS2305: Module 'tslib' has no exported member '__decorate'.
+error TS2305: Module 'tslib' has no exported member '__extends'.
+error TS2305: Module 'tslib' has no exported member '__metadata'.
+error TS2305: Module 'tslib' has no exported member '__param'.
+
+
+!!! error TS2305: Module 'tslib' has no exported member '__decorate'.
+!!! error TS2305: Module 'tslib' has no exported member '__extends'.
+!!! error TS2305: Module 'tslib' has no exported member '__metadata'.
+!!! error TS2305: Module 'tslib' has no exported member '__param'.
+==== tests/cases/compiler/external.ts (0 errors) ====
+    export class A { }
+    export class B extends A { }
+    
+    declare var dec: any;
+    
+    @dec
+    class C {
+        method(@dec x: number) {
+        }
+    }
+    
+==== tests/cases/compiler/script.ts (0 errors) ====
+    class A { }
+    class B extends A { }
+    
+    declare var dec: any;
+    
+    @dec
+    class C {
+        method(@dec x: number) {
+        }
+    }
+    
+==== tests/cases/compiler/tslib.d.ts (0 errors) ====
+    export {}
\ No newline at end of file
diff --git a/tests/baselines/reference/importHelpersNoHelpers.js b/tests/baselines/reference/importHelpersNoHelpers.js
new file mode 100644
index 00000000000..8c5afc99ece
--- /dev/null
+++ b/tests/baselines/reference/importHelpersNoHelpers.js
@@ -0,0 +1,110 @@
+//// [tests/cases/compiler/importHelpersNoHelpers.ts] ////
+
+//// [external.ts]
+export class A { }
+export class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+//// [script.ts]
+class A { }
+class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+//// [tslib.d.ts]
+export {}
+
+//// [external.js]
+"use strict";
+var tslib_1 = require("tslib");
+var A = (function () {
+    function A() {
+    }
+    return A;
+}());
+exports.A = A;
+var B = (function (_super) {
+    tslib_1.__extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    return B;
+}(A));
+exports.B = B;
+var C = (function () {
+    function C() {
+    }
+    C.prototype.method = function (x) {
+    };
+    return C;
+}());
+tslib_1.__decorate([
+    tslib_1.__param(0, dec),
+    tslib_1.__metadata("design:type", Function),
+    tslib_1.__metadata("design:paramtypes", [Number]),
+    tslib_1.__metadata("design:returntype", void 0)
+], C.prototype, "method", null);
+C = tslib_1.__decorate([
+    dec,
+    tslib_1.__metadata("design:paramtypes", [])
+], C);
+//// [script.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+var __param = (this && this.__param) || function (paramIndex, decorator) {
+    return function (target, key) { decorator(target, key, paramIndex); }
+};
+var A = (function () {
+    function A() {
+    }
+    return A;
+}());
+var B = (function (_super) {
+    __extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    return B;
+}(A));
+var C = (function () {
+    function C() {
+    }
+    C.prototype.method = function (x) {
+    };
+    return C;
+}());
+__decorate([
+    __param(0, dec),
+    __metadata("design:type", Function),
+    __metadata("design:paramtypes", [Number]),
+    __metadata("design:returntype", void 0)
+], C.prototype, "method", null);
+C = __decorate([
+    dec,
+    __metadata("design:paramtypes", [])
+], C);
diff --git a/tests/baselines/reference/importHelpersNoModule.errors.txt b/tests/baselines/reference/importHelpersNoModule.errors.txt
new file mode 100644
index 00000000000..d59fd0537ca
--- /dev/null
+++ b/tests/baselines/reference/importHelpersNoModule.errors.txt
@@ -0,0 +1,28 @@
+error TS2307: Cannot find module 'tslib'.
+
+
+!!! error TS2307: Cannot find module 'tslib'.
+==== tests/cases/compiler/external.ts (0 errors) ====
+    export class A { }
+    export class B extends A { }
+    
+    declare var dec: any;
+    
+    @dec
+    class C {
+        method(@dec x: number) {
+        }
+    }
+    
+==== tests/cases/compiler/script.ts (0 errors) ====
+    class A { }
+    class B extends A { }
+    
+    declare var dec: any;
+    
+    @dec
+    class C {
+        method(@dec x: number) {
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/importHelpersNoModule.js b/tests/baselines/reference/importHelpersNoModule.js
new file mode 100644
index 00000000000..36bc0c5f76b
--- /dev/null
+++ b/tests/baselines/reference/importHelpersNoModule.js
@@ -0,0 +1,108 @@
+//// [tests/cases/compiler/importHelpersNoModule.ts] ////
+
+//// [external.ts]
+export class A { }
+export class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+//// [script.ts]
+class A { }
+class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+
+//// [external.js]
+"use strict";
+var tslib_1 = require("tslib");
+var A = (function () {
+    function A() {
+    }
+    return A;
+}());
+exports.A = A;
+var B = (function (_super) {
+    tslib_1.__extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    return B;
+}(A));
+exports.B = B;
+var C = (function () {
+    function C() {
+    }
+    C.prototype.method = function (x) {
+    };
+    return C;
+}());
+tslib_1.__decorate([
+    tslib_1.__param(0, dec),
+    tslib_1.__metadata("design:type", Function),
+    tslib_1.__metadata("design:paramtypes", [Number]),
+    tslib_1.__metadata("design:returntype", void 0)
+], C.prototype, "method", null);
+C = tslib_1.__decorate([
+    dec,
+    tslib_1.__metadata("design:paramtypes", [])
+], C);
+//// [script.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+var __metadata = (this && this.__metadata) || function (k, v) {
+    if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
+};
+var __param = (this && this.__param) || function (paramIndex, decorator) {
+    return function (target, key) { decorator(target, key, paramIndex); }
+};
+var A = (function () {
+    function A() {
+    }
+    return A;
+}());
+var B = (function (_super) {
+    __extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    return B;
+}(A));
+var C = (function () {
+    function C() {
+    }
+    C.prototype.method = function (x) {
+    };
+    return C;
+}());
+__decorate([
+    __param(0, dec),
+    __metadata("design:type", Function),
+    __metadata("design:paramtypes", [Number]),
+    __metadata("design:returntype", void 0)
+], C.prototype, "method", null);
+C = __decorate([
+    dec,
+    __metadata("design:paramtypes", [])
+], C);
diff --git a/tests/baselines/reference/importHelpersOutFile.js b/tests/baselines/reference/importHelpersOutFile.js
index 6071c78416e..cb50330c20c 100644
--- a/tests/baselines/reference/importHelpersOutFile.js
+++ b/tests/baselines/reference/importHelpersOutFile.js
@@ -1,14 +1,24 @@
 //// [tests/cases/compiler/importHelpersOutFile.ts] ////
 
 //// [a.ts]
-export class A { }
+export class A { }
+
 //// [b.ts]
 import { A } from "./a";
-export class B extends A { }
+export class B extends A { }
+
 //// [c.ts]
 import { A } from "./a";
 export class C extends A { }
 
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [out.js]
 define("a", ["require", "exports"], function (require, exports) {
diff --git a/tests/baselines/reference/importHelpersOutFile.symbols b/tests/baselines/reference/importHelpersOutFile.symbols
index cd65e3dcd69..086f3f9995e 100644
--- a/tests/baselines/reference/importHelpersOutFile.symbols
+++ b/tests/baselines/reference/importHelpersOutFile.symbols
@@ -18,3 +18,46 @@ export class C extends A { }
 >C : Symbol(C, Decl(c.ts, 0, 24))
 >A : Symbol(A, Decl(c.ts, 0, 8))
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.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, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>generator : Symbol(generator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/importHelpersOutFile.types b/tests/baselines/reference/importHelpersOutFile.types
index 94726de43e5..96adc466d65 100644
--- a/tests/baselines/reference/importHelpersOutFile.types
+++ b/tests/baselines/reference/importHelpersOutFile.types
@@ -18,3 +18,46 @@ export class C extends A { }
 >C : C
 >A : A
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/baselines/reference/importHelpersSystem.js b/tests/baselines/reference/importHelpersSystem.js
index 664edef5248..3c1ee19ec48 100644
--- a/tests/baselines/reference/importHelpersSystem.js
+++ b/tests/baselines/reference/importHelpersSystem.js
@@ -1,11 +1,20 @@
 //// [tests/cases/compiler/importHelpersSystem.ts] ////
 
 //// [a.ts]
-export class A { }
+export class A { }
+
 //// [b.ts]
 import { A } from "./a";
 export class B extends A { }
 
+//// [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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+
 
 //// [a.js]
 System.register([], function (exports_1, context_1) {
diff --git a/tests/baselines/reference/importHelpersSystem.symbols b/tests/baselines/reference/importHelpersSystem.symbols
index d4155c4bf52..47528a8bba6 100644
--- a/tests/baselines/reference/importHelpersSystem.symbols
+++ b/tests/baselines/reference/importHelpersSystem.symbols
@@ -10,3 +10,46 @@ export class B extends A { }
 >B : Symbol(B, Decl(b.ts, 0, 24))
 >A : Symbol(A, Decl(b.ts, 0, 8))
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : Symbol(__extends, Decl(tslib.d.ts, --, --))
+>d : Symbol(d, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>b : Symbol(b, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.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, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>target : Symbol(target, Decl(tslib.d.ts, --, --))
+>key : Symbol(key, Decl(tslib.d.ts, --, --))
+>desc : Symbol(desc, Decl(tslib.d.ts, --, --))
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : Symbol(__param, Decl(tslib.d.ts, --, --))
+>paramIndex : Symbol(paramIndex, Decl(tslib.d.ts, --, --))
+>decorator : Symbol(decorator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : Symbol(__metadata, Decl(tslib.d.ts, --, --))
+>metadataKey : Symbol(metadataKey, Decl(tslib.d.ts, --, --))
+>metadataValue : Symbol(metadataValue, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : Symbol(__awaiter, Decl(tslib.d.ts, --, --))
+>thisArg : Symbol(thisArg, Decl(tslib.d.ts, --, --))
+>_arguments : Symbol(_arguments, Decl(tslib.d.ts, --, --))
+>P : Symbol(P, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>generator : Symbol(generator, Decl(tslib.d.ts, --, --))
+>Function : Symbol(Function, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/importHelpersSystem.types b/tests/baselines/reference/importHelpersSystem.types
index 7f313d87cd6..9ff756ffaab 100644
--- a/tests/baselines/reference/importHelpersSystem.types
+++ b/tests/baselines/reference/importHelpersSystem.types
@@ -10,3 +10,46 @@ export class B extends A { }
 >B : B
 >A : A
 
+=== tests/cases/compiler/tslib.d.ts ===
+export declare function __extends(d: Function, b: Function): void;
+>__extends : (d: Function, b: Function) => void
+>d : Function
+>Function : Function
+>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[]
+>Function : Function
+>target : any
+>key : string | symbol
+>desc : any
+
+export declare function __param(paramIndex: number, decorator: Function): Function;
+>__param : (paramIndex: number, decorator: Function) => Function
+>paramIndex : number
+>decorator : Function
+>Function : Function
+>Function : Function
+
+export declare function __metadata(metadataKey: any, metadataValue: any): Function;
+>__metadata : (metadataKey: any, metadataValue: any) => Function
+>metadataKey : any
+>metadataValue : any
+>Function : Function
+
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
+>__awaiter : (thisArg: any, _arguments: any, P: Function, generator: Function) => any
+>thisArg : any
+>_arguments : any
+>P : Function
+>Function : Function
+>generator : Function
+>Function : Function
+
diff --git a/tests/cases/compiler/importHelpers.ts b/tests/cases/compiler/importHelpers.ts
index 7a578fa70f3..2e15eb6352b 100644
--- a/tests/cases/compiler/importHelpers.ts
+++ b/tests/cases/compiler/importHelpers.ts
@@ -1,6 +1,7 @@
 // @importHelpers: true
 // @target: es5
 // @module: commonjs
+// @moduleResolution: classic
 // @experimentalDecorators: true
 // @emitDecoratorMetadata: true
 // @filename: external.ts
@@ -25,4 +26,12 @@ declare var dec: any;
 class C {
     method(@dec x: number) {
     }
-}
\ No newline at end of file
+}
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersAmd.ts b/tests/cases/compiler/importHelpersAmd.ts
index 6d21a380178..bef63328d52 100644
--- a/tests/cases/compiler/importHelpersAmd.ts
+++ b/tests/cases/compiler/importHelpersAmd.ts
@@ -3,6 +3,15 @@
 // @module: amd
 // @filename: a.ts
 export class A { }
+
 // @filename: b.ts
 import { A } from "./a";
 export class B extends A { }
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersES6.ts b/tests/cases/compiler/importHelpersES6.ts
index 7dfa70e2325..9be680a88d6 100644
--- a/tests/cases/compiler/importHelpersES6.ts
+++ b/tests/cases/compiler/importHelpersES6.ts
@@ -5,4 +5,12 @@
 declare var dec: any;
 @dec export class A {
 
-}
\ No newline at end of file
+}
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersInIsolatedModules.ts b/tests/cases/compiler/importHelpersInIsolatedModules.ts
index c55ba6e52e4..4c1dfd06ec0 100644
--- a/tests/cases/compiler/importHelpersInIsolatedModules.ts
+++ b/tests/cases/compiler/importHelpersInIsolatedModules.ts
@@ -2,6 +2,7 @@
 // @isolatedModules: true
 // @target: es5
 // @module: commonjs
+// @moduleResolution: classic
 // @experimentalDecorators: true
 // @emitDecoratorMetadata: true
 // @filename: external.ts
@@ -26,4 +27,12 @@ declare var dec: any;
 class C {
     method(@dec x: number) {
     }
-}
\ No newline at end of file
+}
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersInTsx.tsx b/tests/cases/compiler/importHelpersInTsx.tsx
index b1ab98ec5db..32e0e5bf3a0 100644
--- a/tests/cases/compiler/importHelpersInTsx.tsx
+++ b/tests/cases/compiler/importHelpersInTsx.tsx
@@ -1,6 +1,7 @@
 // @importHelpers: true
 // @target: es5
 // @module: commonjs
+// @moduleResolution: classic
 // @jsx: react
 // @experimentalDecorators: true
 // @emitDecoratorMetadata: true
@@ -9,7 +10,15 @@ declare var React: any;
 declare var o: any;
 export const x = <span {...o} />
 
-// @filename: internal.tsx
+// @filename: script.tsx
 declare var React: any;
 declare var o: any;
-const x = <span {...o} />
\ No newline at end of file
+const x = <span {...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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersNoHelpers.ts b/tests/cases/compiler/importHelpersNoHelpers.ts
new file mode 100644
index 00000000000..82428552548
--- /dev/null
+++ b/tests/cases/compiler/importHelpersNoHelpers.ts
@@ -0,0 +1,32 @@
+// @importHelpers: true
+// @target: es5
+// @module: commonjs
+// @moduleResolution: classic
+// @experimentalDecorators: true
+// @emitDecoratorMetadata: true
+// @filename: external.ts
+export class A { }
+export class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+// @filename: script.ts
+class A { }
+class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+// @filename: tslib.d.ts
+export {}
\ No newline at end of file
diff --git a/tests/cases/compiler/importHelpersNoModule.ts b/tests/cases/compiler/importHelpersNoModule.ts
new file mode 100644
index 00000000000..e824f2afb48
--- /dev/null
+++ b/tests/cases/compiler/importHelpersNoModule.ts
@@ -0,0 +1,29 @@
+// @importHelpers: true
+// @target: es5
+// @module: commonjs
+// @moduleResolution: classic
+// @experimentalDecorators: true
+// @emitDecoratorMetadata: true
+// @filename: external.ts
+export class A { }
+export class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
+
+// @filename: script.ts
+class A { }
+class B extends A { }
+
+declare var dec: any;
+
+@dec
+class C {
+    method(@dec x: number) {
+    }
+}
diff --git a/tests/cases/compiler/importHelpersOutFile.ts b/tests/cases/compiler/importHelpersOutFile.ts
index 471f363c65d..69e1e692617 100644
--- a/tests/cases/compiler/importHelpersOutFile.ts
+++ b/tests/cases/compiler/importHelpersOutFile.ts
@@ -4,9 +4,19 @@
 // @outfile: out.js
 // @filename: a.ts
 export class A { }
+
 // @filename: b.ts
 import { A } from "./a";
 export class B extends A { }
+
 // @filename: c.ts
 import { A } from "./a";
 export class C extends A { }
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;
diff --git a/tests/cases/compiler/importHelpersSystem.ts b/tests/cases/compiler/importHelpersSystem.ts
index 1b81e748ff0..5b6081f17f3 100644
--- a/tests/cases/compiler/importHelpersSystem.ts
+++ b/tests/cases/compiler/importHelpersSystem.ts
@@ -3,6 +3,15 @@
 // @module: system
 // @filename: a.ts
 export class A { }
+
 // @filename: b.ts
 import { A } from "./a";
 export class B extends A { }
+
+// @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;
+export declare function __awaiter(thisArg: any, _arguments: any, P: Function, generator: Function): any;