diff --git a/src/compiler/transformers/esnext.ts b/src/compiler/transformers/esnext.ts
index 482f37d45f9..971dddd20ea 100644
--- a/src/compiler/transformers/esnext.ts
+++ b/src/compiler/transformers/esnext.ts
@@ -357,10 +357,12 @@ namespace ts {
             const values = createAsyncValuesHelper(context, expression, /*location*/ node.expression);
             const next = createYield(
                 /*asteriskToken*/ undefined,
-                createArrayLiteral([
-                    createLiteral("await"),
-                    createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, [])
-                ])
+                enclosingFunctionFlags & FunctionFlags.Generator
+                    ? createArrayLiteral([
+                        createLiteral("await"),
+                        createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, [])
+                    ])
+                    : createCall(createPropertyAccess(iterator, "next" ), /*typeArguments*/ undefined, [])
             );
 
             hoistVariableDeclaration(errorRecord);
@@ -431,10 +433,12 @@ namespace ts {
                                     createStatement(
                                         createYield(
                                             /*asteriskToken*/ undefined,
-                                            createArrayLiteral([
-                                                createLiteral("await"),
-                                                createFunctionCall(returnMethod, iterator, [])
-                                            ])
+                                            enclosingFunctionFlags & FunctionFlags.Generator
+                                                ? createArrayLiteral([
+                                                    createLiteral("await"),
+                                                    createFunctionCall(returnMethod, iterator, [])
+                                                ])
+                                                : createFunctionCall(returnMethod, iterator, [])
                                         )
                                     )
                                 ),
@@ -872,6 +876,7 @@ namespace ts {
         scoped: false,
         text: `
             var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+                if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
                 var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
                 return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
                 function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -932,6 +937,7 @@ namespace ts {
         scoped: false,
         text: `
             var __asyncValues = (this && this.__asyncIterator) || function (o) {
+                if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
                 var m = o[Symbol.asyncIterator];
                 return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
             };
diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 92ec0b4ee0e..7446cc84deb 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -3035,6 +3035,33 @@ namespace ts.projectSystem {
             const inferredProject = projectService.inferredProjects[0];
             assert.isTrue(inferredProject.containsFile(<server.NormalizedPath>file1.path));
         });
+
+        it("should be able to handle @types if input file list is empty", () => {
+            const f = {
+                path: "/a/app.ts",
+                content: "let x = 1"
+            };
+            const config = {
+                path: "/a/tsconfig.json",
+                content: JSON.stringify({
+                    compiler: {},
+                    files: []
+                })
+            };
+            const t1 = {
+                path: "/a/node_modules/@types/typings/index.d.ts",
+                content: `export * from "./lib"`
+            };
+            const t2 = {
+                path: "/a/node_modules/@types/typings/lib.d.ts",
+                content: `export const x: number`
+            };
+            const host = createServerHost([f, config, t1, t2], { currentDirectory: getDirectoryPath(f.path) });
+            const projectService = createProjectService(host);
+
+            projectService.openClientFile(f.path);
+            projectService.checkNumberOfProjects({ configuredProjects: 1, inferredProjects: 1 });
+        });
     });
 
     describe("reload", () => {
diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 8f29deb67db..262c2ba21fe 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -140,7 +140,7 @@ interface ObjectConstructor {
       * Creates an object that has the specified prototype or that has null prototype.
       * @param o Object to use as a prototype. May be null.
       */
-    create<T extends object>(o: T | null): T | object;
+    create(o: object | null): any;
 
     /**
       * Creates an object that has the specified prototype, and that optionally contains specified properties.
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 36aa3939c83..d0535e2f528 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -948,9 +948,9 @@ namespace ts.server {
 
         private openConfigFile(configFileName: NormalizedPath, clientFileName?: string): OpenConfigFileResult {
             const conversionResult = this.convertConfigFileContentToProjectOptions(configFileName);
-            const projectOptions = conversionResult.success
+            const projectOptions: ProjectOptions = conversionResult.success
                 ? conversionResult.projectOptions
-                : { files: [], compilerOptions: {} };
+                : { files: [], compilerOptions: {}, typeAcquisition: { enable: false } };
             const project = this.createAndAddConfiguredProject(configFileName, projectOptions, conversionResult.configFileErrors, clientFileName);
             return {
                 success: conversionResult.success,
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index d8faad28b10..c7d27d80d25 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -820,7 +820,7 @@ namespace ts.server.protocol {
      * Represents a file in external project.
      * External project is project whose set of files, compilation options and open\close state
      * is maintained by the client (i.e. if all this data come from .csproj file in Visual Studio).
-     * External project will exist even if all files in it are closed and should be closed explicity.
+     * External project will exist even if all files in it are closed and should be closed explicitly.
      * If external project includes one or more tsconfig.json/jsconfig.json files then tsserver will
      * create configured project for every config file but will maintain a link that these projects were created
      * as a result of opening external project so they should be removed once external project is closed.
diff --git a/src/server/session.ts b/src/server/session.ts
index 262ba8da1da..f1b373c4a90 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1412,6 +1412,9 @@ namespace ts.server {
         }
 
         private getCodeFixes(args: protocol.CodeFixRequestArgs, simplifiedResult: boolean): protocol.CodeAction[] | CodeAction[] {
+            if (args.errorCodes.length === 0) {
+                return undefined;
+            }
             const { file, project } = this.getFileAndProjectWithoutRefreshingInferredProjects(args);
 
             const scriptInfo = project.getScriptInfoForNormalizedPath(file);
diff --git a/tests/baselines/reference/assigningFromObjectToAnythingElse.errors.txt b/tests/baselines/reference/assigningFromObjectToAnythingElse.errors.txt
index 070339e4726..d3395c7ebc9 100644
--- a/tests/baselines/reference/assigningFromObjectToAnythingElse.errors.txt
+++ b/tests/baselines/reference/assigningFromObjectToAnythingElse.errors.txt
@@ -1,11 +1,8 @@
 tests/cases/compiler/assigningFromObjectToAnythingElse.ts(3,1): error TS2322: Type 'Object' is not assignable to type 'RegExp'.
   The 'Object' type is assignable to very few other types. Did you mean to use the 'any' type instead?
     Property 'exec' is missing in type 'Object'.
-tests/cases/compiler/assigningFromObjectToAnythingElse.ts(5,5): error TS2322: Type 'object | Object' is not assignable to type 'String'.
-  Type 'object' is not assignable to type 'String'.
-    Property 'charAt' is missing in type '{}'.
-tests/cases/compiler/assigningFromObjectToAnythingElse.ts(6,5): error TS2322: Type 'object | Number' is not assignable to type 'String'.
-  Type 'object' is not assignable to type 'String'.
+tests/cases/compiler/assigningFromObjectToAnythingElse.ts(5,17): error TS2346: Supplied parameters do not match any signature of call target.
+tests/cases/compiler/assigningFromObjectToAnythingElse.ts(6,17): error TS2346: Supplied parameters do not match any signature of call target.
 tests/cases/compiler/assigningFromObjectToAnythingElse.ts(8,5): error TS2322: Type 'Object' is not assignable to type 'Error'.
   The 'Object' type is assignable to very few other types. Did you mean to use the 'any' type instead?
     Property 'name' is missing in type 'Object'.
@@ -21,14 +18,11 @@ tests/cases/compiler/assigningFromObjectToAnythingElse.ts(8,5): error TS2322: Ty
 !!! error TS2322:     Property 'exec' is missing in type 'Object'.
     
     var a: String = Object.create<Object>("");
-        ~
-!!! error TS2322: Type 'object | Object' is not assignable to type 'String'.
-!!! error TS2322:   Type 'object' is not assignable to type 'String'.
-!!! error TS2322:     Property 'charAt' is missing in type '{}'.
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2346: Supplied parameters do not match any signature of call target.
     var c: String = Object.create<Number>(1);
-        ~
-!!! error TS2322: Type 'object | Number' is not assignable to type 'String'.
-!!! error TS2322:   Type 'object' is not assignable to type 'String'.
+                    ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2346: Supplied parameters do not match any signature of call target.
     
     var w: Error = new Object();
         ~
diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
index 2edcfd99e4b..ba4902102b1 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
@@ -62,6 +62,7 @@ class C9 extends B9 {
 
 //// [C1.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -81,6 +82,7 @@ class C1 {
 }
 //// [C2.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -101,6 +103,7 @@ class C2 {
 }
 //// [C3.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -126,6 +129,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -146,6 +150,7 @@ class C4 {
 }
 //// [C5.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -171,6 +176,7 @@ class C5 {
 }
 //// [C6.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -191,6 +197,7 @@ class C6 {
 }
 //// [C7.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -211,6 +218,7 @@ class C7 {
 }
 //// [C8.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -233,6 +241,7 @@ class C8 {
 }
 //// [C9.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
index 2b296936368..74a65673e5a 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
@@ -89,6 +89,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -141,6 +142,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -199,6 +201,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -262,6 +265,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -330,6 +334,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -410,6 +415,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -468,6 +474,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -520,6 +527,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -585,6 +593,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
index 97df064bbe8..2b0d6db5353 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
@@ -31,6 +31,7 @@ async function * f7() {
 
 //// [F1.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -48,6 +49,7 @@ function f1() {
 }
 //// [F2.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -66,6 +68,7 @@ function f2() {
 }
 //// [F3.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -89,6 +92,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -107,6 +111,7 @@ function f4() {
 }
 //// [F5.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -130,6 +135,7 @@ function f5() {
 }
 //// [F6.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -148,6 +154,7 @@ function f6() {
 }
 //// [F7.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
index 2a1b4393a9b..42098455ed1 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
@@ -58,6 +58,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -105,6 +106,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -158,6 +160,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -216,6 +219,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -279,6 +283,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -354,6 +359,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -407,6 +413,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
index bc64f029289..90f4b70e9bd 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
@@ -31,6 +31,7 @@ const f7 = async function * () {
 
 //// [F1.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -48,6 +49,7 @@ const f1 = function () {
 };
 //// [F2.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -66,6 +68,7 @@ const f2 = function () {
 };
 //// [F3.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -89,6 +92,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -107,6 +111,7 @@ const f4 = function () {
 };
 //// [F5.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -130,6 +135,7 @@ const f5 = function () {
 };
 //// [F6.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -148,6 +154,7 @@ const f6 = function () {
 };
 //// [F7.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
index 9593562987b..a6265063fde 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
@@ -58,6 +58,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -105,6 +106,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -158,6 +160,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -216,6 +219,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -279,6 +283,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -354,6 +359,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -407,6 +413,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
index 3d3af24d030..817b3904f02 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
@@ -45,6 +45,7 @@ const o7 = {
 
 //// [O1.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -64,6 +65,7 @@ const o1 = {
 };
 //// [O2.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -84,6 +86,7 @@ const o2 = {
 };
 //// [O3.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -109,6 +112,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -129,6 +133,7 @@ const o4 = {
 };
 //// [O5.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -154,6 +159,7 @@ const o5 = {
 };
 //// [O6.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -174,6 +180,7 @@ const o6 = {
 };
 //// [O7.js]
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
index f819945f288..a0839d8258d 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
@@ -72,6 +72,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -121,6 +122,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -176,6 +178,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -236,6 +239,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
     function verb(n, f) { return function (v) { return { value: ["delegate", (o[n] || f).call(o, v)], done: false }; }; }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -301,6 +305,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -378,6 +383,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -433,6 +439,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.forAwait.es2015.js b/tests/baselines/reference/emitter.forAwait.es2015.js
index bfd44581b82..a76c3e0b545 100644
--- a/tests/baselines/reference/emitter.forAwait.es2015.js
+++ b/tests/baselines/reference/emitter.forAwait.es2015.js
@@ -35,6 +35,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
@@ -42,14 +43,14 @@ function f1() {
     return __awaiter(this, void 0, void 0, function* () {
         let y;
         try {
-            for (var y_1 = __asyncValues(y), y_1_1 = yield ["await", y_1.next()]; !y_1_1.done; y_1_1 = yield ["await", y_1.next()]) {
+            for (var y_1 = __asyncValues(y), y_1_1 = yield y_1.next(); !y_1_1.done; y_1_1 = yield y_1.next()) {
                 const x = y_1_1.value;
             }
         }
         catch (e_1_1) { e_1 = { error: e_1_1 }; }
         finally {
             try {
-                if (y_1_1 && !y_1_1.done && (_a = y_1.return)) yield ["await", _a.call(y_1)];
+                if (y_1_1 && !y_1_1.done && (_a = y_1.return)) yield _a.call(y_1);
             }
             finally { if (e_1) throw e_1.error; }
         }
@@ -66,6 +67,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
@@ -73,14 +75,14 @@ function f2() {
     return __awaiter(this, void 0, void 0, function* () {
         let x, y;
         try {
-            for (var y_1 = __asyncValues(y), y_1_1 = yield ["await", y_1.next()]; !y_1_1.done; y_1_1 = yield ["await", y_1.next()]) {
+            for (var y_1 = __asyncValues(y), y_1_1 = yield y_1.next(); !y_1_1.done; y_1_1 = yield y_1.next()) {
                 x = y_1_1.value;
             }
         }
         catch (e_1_1) { e_1 = { error: e_1_1 }; }
         finally {
             try {
-                if (y_1_1 && !y_1_1.done && (_a = y_1.return)) yield ["await", _a.call(y_1)];
+                if (y_1_1 && !y_1_1.done && (_a = y_1.return)) yield _a.call(y_1);
             }
             finally { if (e_1) throw e_1.error; }
         }
@@ -89,10 +91,12 @@ function f2() {
 }
 //// [file3.js]
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -124,10 +128,12 @@ function f3() {
 }
 //// [file4.js]
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/emitter.forAwait.es5.js b/tests/baselines/reference/emitter.forAwait.es5.js
index 5b904cf10a7..efbbe872b3f 100644
--- a/tests/baselines/reference/emitter.forAwait.es5.js
+++ b/tests/baselines/reference/emitter.forAwait.es5.js
@@ -62,6 +62,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
@@ -73,7 +74,7 @@ function f1() {
                 case 0:
                     _c.trys.push([0, 6, 7, 12]);
                     y_1 = __asyncValues(y);
-                    return [4 /*yield*/, ["await", y_1.next()]];
+                    return [4 /*yield*/, y_1.next()];
                 case 1:
                     y_1_1 = _c.sent();
                     _c.label = 2;
@@ -81,7 +82,7 @@ function f1() {
                     if (!!y_1_1.done) return [3 /*break*/, 5];
                     x = y_1_1.value;
                     _c.label = 3;
-                case 3: return [4 /*yield*/, ["await", y_1.next()]];
+                case 3: return [4 /*yield*/, y_1.next()];
                 case 4:
                     y_1_1 = _c.sent();
                     return [3 /*break*/, 2];
@@ -93,7 +94,7 @@ function f1() {
                 case 7:
                     _c.trys.push([7, , 10, 11]);
                     if (!(y_1_1 && !y_1_1.done && (_b = y_1.return))) return [3 /*break*/, 9];
-                    return [4 /*yield*/, ["await", _b.call(y_1)]];
+                    return [4 /*yield*/, _b.call(y_1)];
                 case 8:
                     _c.sent();
                     _c.label = 9;
@@ -144,6 +145,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
@@ -155,7 +157,7 @@ function f2() {
                 case 0:
                     _c.trys.push([0, 6, 7, 12]);
                     y_1 = __asyncValues(y);
-                    return [4 /*yield*/, ["await", y_1.next()]];
+                    return [4 /*yield*/, y_1.next()];
                 case 1:
                     y_1_1 = _c.sent();
                     _c.label = 2;
@@ -163,7 +165,7 @@ function f2() {
                     if (!!y_1_1.done) return [3 /*break*/, 5];
                     x = y_1_1.value;
                     _c.label = 3;
-                case 3: return [4 /*yield*/, ["await", y_1.next()]];
+                case 3: return [4 /*yield*/, y_1.next()];
                 case 4:
                     y_1_1 = _c.sent();
                     return [3 /*break*/, 2];
@@ -175,7 +177,7 @@ function f2() {
                 case 7:
                     _c.trys.push([7, , 10, 11]);
                     if (!(y_1_1 && !y_1_1.done && (_b = y_1.return))) return [3 /*break*/, 9];
-                    return [4 /*yield*/, ["await", _b.call(y_1)]];
+                    return [4 /*yield*/, _b.call(y_1)];
                 case 8:
                     _c.sent();
                     _c.label = 9;
@@ -218,10 +220,12 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
@@ -304,10 +308,12 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var __asyncValues = (this && this.__asyncIterator) || function (o) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var m = o[Symbol.asyncIterator];
     return m ? m.call(o) : typeof __values === "function" ? __values(o) : o[Symbol.iterator]();
 };
 var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
+    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
     var g = generator.apply(thisArg, _arguments || []), q = [], c, i;
     return i = { next: verb("next"), "throw": verb("throw"), "return": verb("return") }, i[Symbol.asyncIterator] = function () { return this; }, i;
     function verb(n) { return function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]), next(); }); }; }
diff --git a/tests/baselines/reference/objectCreate.types b/tests/baselines/reference/objectCreate.types
index 028c98af817..b4e0e72061e 100644
--- a/tests/baselines/reference/objectCreate.types
+++ b/tests/baselines/reference/objectCreate.types
@@ -7,19 +7,19 @@ declare var union: null | { a: number, b: string };
 >b : string
 
 var n = Object.create(null);             // object
->n : object
->Object.create(null) : object
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>n : any
+>Object.create(null) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >null : null
 
 var t = Object.create({ a: 1, b: "" });  // {a: number, b: string }
->t : object | { a: number; b: string; }
->Object.create({ a: 1, b: "" }) : object | { a: number; b: string; }
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>t : any
+>Object.create({ a: 1, b: "" }) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >{ a: 1, b: "" } : { a: number; b: string; }
 >a : number
 >1 : 1
@@ -27,45 +27,45 @@ var t = Object.create({ a: 1, b: "" });  // {a: number, b: string }
 >"" : ""
 
 var u = Object.create(union);            // object | {a: number, b: string }
->u : object | { a: number; b: string; }
->Object.create(union) : object | { a: number; b: string; }
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>u : any
+>Object.create(union) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >union : { a: number; b: string; } | null
 
 var e = Object.create({});               // {}
->e : object | {}
->Object.create({}) : object | {}
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>e : any
+>Object.create({}) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >{} : {}
 
 var o = Object.create(<object>{});       // object
->o : object
->Object.create(<object>{}) : object
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>o : any
+>Object.create(<object>{}) : any
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 ><object>{} : object
 >{} : {}
 
 var a = Object.create(null, {});           // any
 >a : any
 >Object.create(null, {}) : any
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >null : null
 >{} : {}
 
 var a = Object.create({ a: 1, b: "" }, {});
 >a : any
 >Object.create({ a: 1, b: "" }, {}) : any
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >{ a: 1, b: "" } : { a: number; b: string; }
 >a : number
 >1 : 1
@@ -76,27 +76,27 @@ var a = Object.create({ a: 1, b: "" }, {});
 var a = Object.create(union, {});
 >a : any
 >Object.create(union, {}) : any
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >union : { a: number; b: string; } | null
 >{} : {}
 
 var a = Object.create({}, {});
 >a : any
 >Object.create({}, {}) : any
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >{} : {}
 >{} : {}
 
 var a = Object.create(<object>{}, {});
 >a : any
 >Object.create(<object>{}, {}) : any
->Object.create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T | null): object | T; (o: object | null, properties: PropertyDescriptorMap): any; }
+>create : { (o: object | null): any; (o: object | null, properties: PropertyDescriptorMap): any; }
 ><object>{} : object
 >{} : {}
 >{} : {}
diff --git a/tests/baselines/reference/objectCreate2.types b/tests/baselines/reference/objectCreate2.types
index 1b33723b0c9..3e19c08bfc0 100644
--- a/tests/baselines/reference/objectCreate2.types
+++ b/tests/baselines/reference/objectCreate2.types
@@ -9,17 +9,17 @@ declare var union: null | { a: number, b: string };
 var n = Object.create(null);             // any
 >n : any
 >Object.create(null) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >null : null
 
 var t = Object.create({ a: 1, b: "" });  // {a: number, b: string }
->t : object | { a: number; b: string; }
->Object.create({ a: 1, b: "" }) : object | { a: number; b: string; }
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>t : any
+>Object.create({ a: 1, b: "" }) : any
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >{ a: 1, b: "" } : { a: number; b: string; }
 >a : number
 >1 : 1
@@ -27,45 +27,45 @@ var t = Object.create({ a: 1, b: "" });  // {a: number, b: string }
 >"" : ""
 
 var u = Object.create(union);            // {a: number, b: string }
->u : object | { a: number; b: string; }
->Object.create(union) : object | { a: number; b: string; }
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>u : any
+>Object.create(union) : any
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >union : { a: number; b: string; }
 
 var e = Object.create({});               // {}
->e : object | {}
->Object.create({}) : object | {}
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>e : any
+>Object.create({}) : any
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >{} : {}
 
 var o = Object.create(<object>{});       // object
->o : object
->Object.create(<object>{}) : object
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>o : any
+>Object.create(<object>{}) : any
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 ><object>{} : object
 >{} : {}
 
 var a = Object.create(null, {});           // any
 >a : any
 >Object.create(null, {}) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >null : null
 >{} : {}
 
 var a = Object.create({ a: 1, b: "" }, {});
 >a : any
 >Object.create({ a: 1, b: "" }, {}) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >{ a: 1, b: "" } : { a: number; b: string; }
 >a : number
 >1 : 1
@@ -76,27 +76,27 @@ var a = Object.create({ a: 1, b: "" }, {});
 var a = Object.create(union, {});
 >a : any
 >Object.create(union, {}) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >union : { a: number; b: string; }
 >{} : {}
 
 var a = Object.create({}, {});
 >a : any
 >Object.create({}, {}) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >{} : {}
 >{} : {}
 
 var a = Object.create(<object>{}, {});
 >a : any
 >Object.create(<object>{}, {}) : any
->Object.create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>Object.create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 >Object : ObjectConstructor
->create : { <T extends object>(o: T): object | T; (o: object, properties: PropertyDescriptorMap): any; }
+>create : { (o: object): any; (o: object, properties: PropertyDescriptorMap): any; }
 ><object>{} : object
 >{} : {}
 >{} : {}