From eddc4411e9bfbfd5d88d34e401611c57b35b5f67 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Fri, 2 Aug 2024 10:55:16 -0400
Subject: [PATCH 1/2] Use global 'Iterator.prototype' for downlevel generators

---
 src/compiler/factory/emitHelpers.ts           |  6 +--
 .../unittests/evaluation/asyncGenerator.ts    | 22 ++++++++
 .../unittests/evaluation/generator.ts         | 22 ++++++++
 .../reference/asyncArrowFunction11_es5.js     |  4 +-
 .../asyncAwaitIsolatedModules_es5.js          |  4 +-
 tests/baselines/reference/asyncAwait_es5.js   |  4 +-
 .../reference/asyncFunctionNoReturnType.js    |  4 +-
 ...asyncFunctionReturnExpressionErrorSpans.js |  4 +-
 .../asyncFunctionTempVariableScoping.js       |  4 +-
 ...ncFunctionWithForStatementNoInitializer.js |  4 +-
 .../reference/asyncImportNestedYield.js       |  6 +--
 .../reference/asyncImportedPromise_es5.js     |  4 +-
 .../baselines/reference/asyncMultiFile_es5.js |  4 +-
 ...awaitUsingDeclarations.1(target=es2015).js |  2 +-
 ...awaitUsingDeclarations.1(target=es2017).js |  2 +-
 .../awaitUsingDeclarations.1(target=es5).js   |  6 +--
 .../awaitUsingDeclarations.2(target=es5).js   |  4 +-
 .../awaitUsingDeclarations.3(target=es5).js   |  4 +-
 ...awaitUsingDeclarationsInFor(target=es5).js |  4 +-
 ...ingDeclarationsInForAwaitOf(target=es5).js |  4 +-
 ...gDeclarationsInForAwaitOf.3(target=es5).js |  4 +-
 ...tUsingDeclarationsInForOf.1(target=es5).js |  4 +-
 ...tUsingDeclarationsInForOf.5(target=es5).js |  4 +-
 ...blockScopedBindingsInDownlevelGenerator.js |  4 +-
 .../blockScopedVariablesUseBeforeDef.js       |  6 +--
 tests/baselines/reference/castOfYield.js      |  4 +-
 .../checkJsxSubtleSkipContextSensitiveBug.js  |  4 +-
 .../baselines/reference/classStaticBlock6.js  |  4 +-
 .../baselines/reference/classStaticBlock7.js  |  4 +-
 .../reference/contextualReturnTypeOfIIFE.js   |  4 +-
 .../controlFlowForCatchAndFinally.js          |  4 +-
 .../reference/correctOrderOfPromiseMethod.js  |  4 +-
 .../reference/declarationEmitPrivateAsync.js  |  4 +-
 .../dependentDestructuredVariables.js         |  2 +-
 .../destructureOfVariableSameAsShorthand.js   |  4 +-
 .../destructuringControlFlowNoCrash.js        |  4 +-
 ...tElaborateAssignabilityToTypeParameters.js |  4 +-
 ...ter.asyncGenerators.classMethods.es2015.js | 18 +++----
 ...mitter.asyncGenerators.classMethods.es5.js | 54 +++++++++----------
 ...cGenerators.functionDeclarations.es2015.js | 14 ++---
 ...syncGenerators.functionDeclarations.es5.js | 42 +++++++--------
 ...ncGenerators.functionExpressions.es2015.js | 14 ++---
 ...asyncGenerators.functionExpressions.es5.js | 42 +++++++--------
 ...cGenerators.objectLiteralMethods.es2015.js | 14 ++---
 ...syncGenerators.objectLiteralMethods.es5.js | 42 +++++++--------
 .../emitter.forAwait(target=es2015).js        |  8 +--
 .../emitter.forAwait(target=es2017).js        |  8 +--
 .../reference/emitter.forAwait(target=es5).js | 36 ++++++-------
 .../baselines/reference/es5-asyncFunction.js  |  4 +-
 .../es5-asyncFunctionLongObjectLiteral.js     |  4 +-
 .../es5-importHelpersAsyncFunctions.js        |  4 +-
 .../exportDefaultFunctionInNamespace.js       |  4 +-
 ...essionsForbiddenInParameterInitializers.js |  4 +-
 .../forAwaitPerIterationBindingDownlevel.js   |  6 +--
 .../baselines/reference/importAttributes7.js  |  4 +-
 .../importCallExpressionAsyncES5AMD.js        |  4 +-
 .../importCallExpressionAsyncES5CJS.js        |  4 +-
 .../importCallExpressionAsyncES5System.js     |  4 +-
 .../importCallExpressionAsyncES5UMD.js        |  4 +-
 .../importCallExpressionNestedAMD2.js         |  4 +-
 .../importCallExpressionNestedCJS2.js         |  4 +-
 .../importCallExpressionNestedES20152.js      |  4 +-
 .../importCallExpressionNestedES20202.js      |  4 +-
 .../importCallExpressionNestedSystem2.js      |  4 +-
 .../importCallExpressionNestedUMD2.js         |  4 +-
 ...portCallExpressionNoModuleKindSpecified.js |  4 +-
 .../importMeta(module=commonjs,target=es5).js |  4 +-
 .../importMeta(module=es2020,target=es5).js   |  4 +-
 .../importMeta(module=esnext,target=es5).js   |  4 +-
 .../importMeta(module=system,target=es5).js   |  4 +-
 .../invalidContinueInDownlevelAsync.js        |  4 +-
 .../jsFileCompilationAwaitModifier.js         |  4 +-
 tests/baselines/reference/jsxElementType.js   |  4 +-
 .../reference/labeledStatementWithLabel.js    |  4 +-
 ...lesExportsSpecifierGenerationConditions.js |  4 +-
 .../neverAsDiscriminantType(strict=false).js  |  4 +-
 .../neverAsDiscriminantType(strict=true).js   |  4 +-
 tests/baselines/reference/objectRestSpread.js |  2 +-
 .../operationsAvailableOnPromisedType.js      |  4 +-
 .../parenthesizedAsyncArrowFunction.js        |  4 +-
 .../privateNamesIncompatibleModifiers.js      |  2 +-
 .../reference/promiseDefinitionTest.js        |  4 +-
 ...uxLikeDeferredInferenceAllowsAssignment.js |  4 +-
 ...fParamsFromGeneratorMakesRequiredParams.js |  4 +-
 .../templateStringWithEmbeddedYieldKeyword.js |  4 +-
 .../transformNestedGeneratorsWithTry.js       |  4 +-
 .../usingDeclarations.1(target=es2015).js     |  2 +-
 .../usingDeclarations.1(target=es2017).js     |  2 +-
 .../usingDeclarations.1(target=es5).js        |  6 +--
 ...ingDeclarationsInForAwaitOf(target=es5).js |  4 +-
 .../yieldInForInInDownlevelGenerator.js       |  4 +-
 91 files changed, 345 insertions(+), 301 deletions(-)

diff --git a/src/compiler/factory/emitHelpers.ts b/src/compiler/factory/emitHelpers.ts
index 3b3dc97ddb43f..8cc453299e3f8 100644
--- a/src/compiler/factory/emitHelpers.ts
+++ b/src/compiler/factory/emitHelpers.ts
@@ -836,7 +836,7 @@ const asyncGeneratorHelper: UnscopedEmitHelper = {
         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 || []), i, q = [];
-            return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+            return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
             function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
             function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
             function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -1102,8 +1102,8 @@ const generatorHelper: UnscopedEmitHelper = {
     priority: 6,
     text: `
             var __generator = (this && this.__generator) || function (thisArg, body) {
-                var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-                return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+                var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+                return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
                 function verb(n) { return function (v) { return step([n, v]); }; }
                 function step(op) {
                     if (f) throw new TypeError("Generator is already executing.");
diff --git a/src/testRunner/unittests/evaluation/asyncGenerator.ts b/src/testRunner/unittests/evaluation/asyncGenerator.ts
index 78c54bde9238e..e7fb37f26e496 100644
--- a/src/testRunner/unittests/evaluation/asyncGenerator.ts
+++ b/src/testRunner/unittests/evaluation/asyncGenerator.ts
@@ -83,4 +83,26 @@ describe("unittests:: evaluation:: asyncGeneratorEvaluation", () => {
             { done: true, value: 2 },
         ]);
     });
+    it("Supports global `AsyncIterator.prototype` if present", () => {
+        class AsyncIterator { }
+        const { gen } = evaluator.evaluateTypeScript(
+            `
+            export async function * gen() {}
+            `,
+            { target: ts.ScriptTarget.ES5 },
+            { AsyncIterator },
+        );
+        const g = gen();
+        assert.instanceOf(g, AsyncIterator);
+    });
+    it("Ignores global `AsyncIterator.prototype` if missing", () => {
+        const { gen } = evaluator.evaluateTypeScript(
+            `
+            export async function * gen() {}
+            `,
+            { target: ts.ScriptTarget.ES5 },
+            { AsyncIterator: undefined },
+        );
+        gen();
+    });
 });
diff --git a/src/testRunner/unittests/evaluation/generator.ts b/src/testRunner/unittests/evaluation/generator.ts
index 06f22c3680fa5..7d569772e0d23 100644
--- a/src/testRunner/unittests/evaluation/generator.ts
+++ b/src/testRunner/unittests/evaluation/generator.ts
@@ -39,4 +39,26 @@ describe("unittests:: evaluation:: generatorEvaluation", () => {
         assert.deepEqual(g.next(), { value: undefined, done: true });
         assert.deepEqual(output, []);
     });
+    it("Supports global `Iterator.prototype` if present", () => {
+        class Iterator { }
+        const { gen } = evaluator.evaluateTypeScript(
+            `
+            export function * gen() {}
+            `,
+            { target: ts.ScriptTarget.ES5 },
+            { Iterator },
+        );
+        const g = gen();
+        assert.instanceOf(g, Iterator);
+    });
+    it("Ignores global `Iterator.prototype` if missing", () => {
+        const { gen } = evaluator.evaluateTypeScript(
+            `
+            export function * gen() {}
+            `,
+            { target: ts.ScriptTarget.ES5 },
+            { Iterator: undefined },
+        );
+        gen();
+    });
 });
diff --git a/tests/baselines/reference/asyncArrowFunction11_es5.js b/tests/baselines/reference/asyncArrowFunction11_es5.js
index 3f1f3491d7aca..932079f3c83f9 100644
--- a/tests/baselines/reference/asyncArrowFunction11_es5.js
+++ b/tests/baselines/reference/asyncArrowFunction11_es5.js
@@ -20,8 +20,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
index 7c763f9ecf8ab..c5e0e7aaa34f5 100644
--- a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
+++ b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.js
@@ -53,8 +53,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncAwait_es5.js b/tests/baselines/reference/asyncAwait_es5.js
index 2fd12346bb883..8bc581f48de17 100644
--- a/tests/baselines/reference/asyncAwait_es5.js
+++ b/tests/baselines/reference/asyncAwait_es5.js
@@ -59,8 +59,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncFunctionNoReturnType.js b/tests/baselines/reference/asyncFunctionNoReturnType.js
index fb4f9585cc2ae..ef0a529fcc5ad 100644
--- a/tests/baselines/reference/asyncFunctionNoReturnType.js
+++ b/tests/baselines/reference/asyncFunctionNoReturnType.js
@@ -18,8 +18,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncFunctionReturnExpressionErrorSpans.js b/tests/baselines/reference/asyncFunctionReturnExpressionErrorSpans.js
index 523416cff6a76..2863404726a47 100644
--- a/tests/baselines/reference/asyncFunctionReturnExpressionErrorSpans.js
+++ b/tests/baselines/reference/asyncFunctionReturnExpressionErrorSpans.js
@@ -34,8 +34,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncFunctionTempVariableScoping.js b/tests/baselines/reference/asyncFunctionTempVariableScoping.js
index 16b6afaf7a54d..a5a52a5c518b7 100644
--- a/tests/baselines/reference/asyncFunctionTempVariableScoping.js
+++ b/tests/baselines/reference/asyncFunctionTempVariableScoping.js
@@ -17,8 +17,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncFunctionWithForStatementNoInitializer.js b/tests/baselines/reference/asyncFunctionWithForStatementNoInitializer.js
index ddc852cb93a92..8ea440e35cad1 100644
--- a/tests/baselines/reference/asyncFunctionWithForStatementNoInitializer.js
+++ b/tests/baselines/reference/asyncFunctionWithForStatementNoInitializer.js
@@ -37,8 +37,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncImportNestedYield.js b/tests/baselines/reference/asyncImportNestedYield.js
index f7e42c3e3df25..a6251abe5203d 100644
--- a/tests/baselines/reference/asyncImportNestedYield.js
+++ b/tests/baselines/reference/asyncImportNestedYield.js
@@ -7,8 +7,8 @@ async function* foo() {
 
 //// [asyncImportNestedYield.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -37,7 +37,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/asyncImportedPromise_es5.js b/tests/baselines/reference/asyncImportedPromise_es5.js
index aaaf4a95491f8..c6841ddd8a6f1 100644
--- a/tests/baselines/reference/asyncImportedPromise_es5.js
+++ b/tests/baselines/reference/asyncImportedPromise_es5.js
@@ -48,8 +48,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/asyncMultiFile_es5.js b/tests/baselines/reference/asyncMultiFile_es5.js
index 2dd73b8b6c76e..e022b1e864a6b 100644
--- a/tests/baselines/reference/asyncMultiFile_es5.js
+++ b/tests/baselines/reference/asyncMultiFile_es5.js
@@ -16,8 +16,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarations.1(target=es2015).js b/tests/baselines/reference/awaitUsingDeclarations.1(target=es2015).js
index 60d690d76bda0..6468ced72c728 100644
--- a/tests/baselines/reference/awaitUsingDeclarations.1(target=es2015).js
+++ b/tests/baselines/reference/awaitUsingDeclarations.1(target=es2015).js
@@ -165,7 +165,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/awaitUsingDeclarations.1(target=es2017).js b/tests/baselines/reference/awaitUsingDeclarations.1(target=es2017).js
index 31b8b0bdf0b82..1277db5bcdd32 100644
--- a/tests/baselines/reference/awaitUsingDeclarations.1(target=es2017).js
+++ b/tests/baselines/reference/awaitUsingDeclarations.1(target=es2017).js
@@ -156,7 +156,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/awaitUsingDeclarations.1(target=es5).js b/tests/baselines/reference/awaitUsingDeclarations.1(target=es5).js
index a34ff4098232c..eb4005130a99b 100644
--- a/tests/baselines/reference/awaitUsingDeclarations.1(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarations.1(target=es5).js
@@ -110,8 +110,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -192,7 +192,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/awaitUsingDeclarations.2(target=es5).js b/tests/baselines/reference/awaitUsingDeclarations.2(target=es5).js
index 80fa7d99ba97b..7241ac59bb64e 100644
--- a/tests/baselines/reference/awaitUsingDeclarations.2(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarations.2(target=es5).js
@@ -19,8 +19,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarations.3(target=es5).js b/tests/baselines/reference/awaitUsingDeclarations.3(target=es5).js
index 57e87730665f5..c774b207cdb52 100644
--- a/tests/baselines/reference/awaitUsingDeclarations.3(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarations.3(target=es5).js
@@ -21,8 +21,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarationsInFor(target=es5).js b/tests/baselines/reference/awaitUsingDeclarationsInFor(target=es5).js
index f01f673a98836..d8226409a5dac 100644
--- a/tests/baselines/reference/awaitUsingDeclarationsInFor(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarationsInFor(target=es5).js
@@ -20,8 +20,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf(target=es5).js b/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf(target=es5).js
index 2e401a484063b..4deda344151fc 100644
--- a/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf(target=es5).js
@@ -17,8 +17,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf.3(target=es5).js b/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf.3(target=es5).js
index abe97e09c15d0..f929d3d0c6ced 100644
--- a/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf.3(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarationsInForAwaitOf.3(target=es5).js
@@ -24,8 +24,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarationsInForOf.1(target=es5).js b/tests/baselines/reference/awaitUsingDeclarationsInForOf.1(target=es5).js
index 3dab903ba3c89..b48951bbe6d5e 100644
--- a/tests/baselines/reference/awaitUsingDeclarationsInForOf.1(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarationsInForOf.1(target=es5).js
@@ -18,8 +18,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/awaitUsingDeclarationsInForOf.5(target=es5).js b/tests/baselines/reference/awaitUsingDeclarationsInForOf.5(target=es5).js
index 1b0ea1fd6307e..6b9e8308d45a9 100644
--- a/tests/baselines/reference/awaitUsingDeclarationsInForOf.5(target=es5).js
+++ b/tests/baselines/reference/awaitUsingDeclarationsInForOf.5(target=es5).js
@@ -24,8 +24,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/blockScopedBindingsInDownlevelGenerator.js b/tests/baselines/reference/blockScopedBindingsInDownlevelGenerator.js
index fa6167ff384bf..ca74ec4d9ddb1 100644
--- a/tests/baselines/reference/blockScopedBindingsInDownlevelGenerator.js
+++ b/tests/baselines/reference/blockScopedBindingsInDownlevelGenerator.js
@@ -10,8 +10,8 @@ function* a() {
 
 //// [blockScopedBindingsInDownlevelGenerator.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/blockScopedVariablesUseBeforeDef.js b/tests/baselines/reference/blockScopedVariablesUseBeforeDef.js
index fa9bd38069f63..92f6719edaf89 100644
--- a/tests/baselines/reference/blockScopedVariablesUseBeforeDef.js
+++ b/tests/baselines/reference/blockScopedVariablesUseBeforeDef.js
@@ -164,8 +164,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -198,7 +198,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/castOfYield.js b/tests/baselines/reference/castOfYield.js
index 0392eb7e354fa..94de9e5dddfdd 100644
--- a/tests/baselines/reference/castOfYield.js
+++ b/tests/baselines/reference/castOfYield.js
@@ -10,8 +10,8 @@ function* f() {
 
 //// [castOfYield.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/checkJsxSubtleSkipContextSensitiveBug.js b/tests/baselines/reference/checkJsxSubtleSkipContextSensitiveBug.js
index 0393f492811df..2eca8424cd89c 100644
--- a/tests/baselines/reference/checkJsxSubtleSkipContextSensitiveBug.js
+++ b/tests/baselines/reference/checkJsxSubtleSkipContextSensitiveBug.js
@@ -53,8 +53,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/classStaticBlock6.js b/tests/baselines/reference/classStaticBlock6.js
index ff75c42c44a50..be445fb7d4969 100644
--- a/tests/baselines/reference/classStaticBlock6.js
+++ b/tests/baselines/reference/classStaticBlock6.js
@@ -91,8 +91,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/classStaticBlock7.js b/tests/baselines/reference/classStaticBlock7.js
index 238a20e14297d..29d74bf42609d 100644
--- a/tests/baselines/reference/classStaticBlock7.js
+++ b/tests/baselines/reference/classStaticBlock7.js
@@ -57,8 +57,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/contextualReturnTypeOfIIFE.js b/tests/baselines/reference/contextualReturnTypeOfIIFE.js
index 74b82182ceb1b..7baee9f0d4c96 100644
--- a/tests/baselines/reference/contextualReturnTypeOfIIFE.js
+++ b/tests/baselines/reference/contextualReturnTypeOfIIFE.js
@@ -25,8 +25,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/controlFlowForCatchAndFinally.js b/tests/baselines/reference/controlFlowForCatchAndFinally.js
index 949a178f7e413..65f0fe897cc92 100644
--- a/tests/baselines/reference/controlFlowForCatchAndFinally.js
+++ b/tests/baselines/reference/controlFlowForCatchAndFinally.js
@@ -54,8 +54,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/correctOrderOfPromiseMethod.js b/tests/baselines/reference/correctOrderOfPromiseMethod.js
index 900ffee4fb9cc..4ae573b834198 100644
--- a/tests/baselines/reference/correctOrderOfPromiseMethod.js
+++ b/tests/baselines/reference/correctOrderOfPromiseMethod.js
@@ -43,8 +43,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/declarationEmitPrivateAsync.js b/tests/baselines/reference/declarationEmitPrivateAsync.js
index 336c908724ff4..b3da5fed3f089 100644
--- a/tests/baselines/reference/declarationEmitPrivateAsync.js
+++ b/tests/baselines/reference/declarationEmitPrivateAsync.js
@@ -19,8 +19,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/dependentDestructuredVariables.js b/tests/baselines/reference/dependentDestructuredVariables.js
index 7d32808909bf7..a91ecf55ada98 100644
--- a/tests/baselines/reference/dependentDestructuredVariables.js
+++ b/tests/baselines/reference/dependentDestructuredVariables.js
@@ -482,7 +482,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/destructureOfVariableSameAsShorthand.js b/tests/baselines/reference/destructureOfVariableSameAsShorthand.js
index 26cf986a844e3..c8e0620ea8ae9 100644
--- a/tests/baselines/reference/destructureOfVariableSameAsShorthand.js
+++ b/tests/baselines/reference/destructureOfVariableSameAsShorthand.js
@@ -39,8 +39,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/destructuringControlFlowNoCrash.js b/tests/baselines/reference/destructuringControlFlowNoCrash.js
index 8335829ac4335..1cadd21894ac1 100644
--- a/tests/baselines/reference/destructuringControlFlowNoCrash.js
+++ b/tests/baselines/reference/destructuringControlFlowNoCrash.js
@@ -30,8 +30,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/doNotElaborateAssignabilityToTypeParameters.js b/tests/baselines/reference/doNotElaborateAssignabilityToTypeParameters.js
index 5d8d8ca8f4bb5..e0cc967c19563 100644
--- a/tests/baselines/reference/doNotElaborateAssignabilityToTypeParameters.js
+++ b/tests/baselines/reference/doNotElaborateAssignabilityToTypeParameters.js
@@ -25,8 +25,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
index 5be6ad0fe3911..34333f4d0bc8e 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
@@ -65,7 +65,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -85,7 +85,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -106,7 +106,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -139,7 +139,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -160,7 +160,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -193,7 +193,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -214,7 +214,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -235,7 +235,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -258,7 +258,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
index 9bbe5eb71297e..d39903e283504 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
@@ -62,8 +62,8 @@ class C9 extends B9 {
 
 //// [C1.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -92,7 +92,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -115,8 +115,8 @@ var C1 = /** @class */ (function () {
 }());
 //// [C2.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -145,7 +145,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -175,8 +175,8 @@ var C2 = /** @class */ (function () {
 }());
 //// [C3.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -205,7 +205,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -235,8 +235,8 @@ var C3 = /** @class */ (function () {
 }());
 //// [C4.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -277,7 +277,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -318,8 +318,8 @@ var C4 = /** @class */ (function () {
 }());
 //// [C5.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -348,7 +348,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -409,8 +409,8 @@ var C5 = /** @class */ (function () {
 }());
 //// [C6.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -439,7 +439,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -468,8 +468,8 @@ var C6 = /** @class */ (function () {
 }());
 //// [C7.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -498,7 +498,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -524,8 +524,8 @@ var C7 = /** @class */ (function () {
 }());
 //// [C8.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -554,7 +554,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -595,8 +595,8 @@ var __extends = (this && this.__extends) || (function () {
     };
 })();
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -625,7 +625,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
index bebb30336dbb2..2271510771807 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
@@ -34,7 +34,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -52,7 +52,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -71,7 +71,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -102,7 +102,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -121,7 +121,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -152,7 +152,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -171,7 +171,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
index 04b4bc949ac78..a129d13003af0 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
@@ -31,8 +31,8 @@ async function * f7() {
 
 //// [F1.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -61,7 +61,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -79,8 +79,8 @@ function f1() {
 }
 //// [F2.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -109,7 +109,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -134,8 +134,8 @@ function f2() {
 }
 //// [F3.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -164,7 +164,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -189,8 +189,8 @@ function f3() {
 }
 //// [F4.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -231,7 +231,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -267,8 +267,8 @@ function f4() {
 }
 //// [F5.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -297,7 +297,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -353,8 +353,8 @@ function f5() {
 }
 //// [F6.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -383,7 +383,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -407,8 +407,8 @@ function f6() {
 }
 //// [F7.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -437,7 +437,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
index e89e9b9d6a89f..88ae6f0e40597 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
@@ -34,7 +34,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -52,7 +52,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -71,7 +71,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -102,7 +102,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -121,7 +121,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -152,7 +152,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -171,7 +171,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
index 699df6cff0b1b..e4076be6c7a0b 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
@@ -31,8 +31,8 @@ const f7 = async function * () {
 
 //// [F1.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -61,7 +61,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -79,8 +79,8 @@ var f1 = function () {
 };
 //// [F2.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -109,7 +109,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -134,8 +134,8 @@ var f2 = function () {
 };
 //// [F3.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -164,7 +164,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -189,8 +189,8 @@ var f3 = function () {
 };
 //// [F4.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -231,7 +231,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -267,8 +267,8 @@ var f4 = function () {
 };
 //// [F5.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -297,7 +297,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -353,8 +353,8 @@ var f5 = function () {
 };
 //// [F6.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -383,7 +383,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -407,8 +407,8 @@ var f6 = function () {
 };
 //// [F7.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -437,7 +437,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
index 97ea27906a2c4..e24410353e555 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
@@ -48,7 +48,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -68,7 +68,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -89,7 +89,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -122,7 +122,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -143,7 +143,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -176,7 +176,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -197,7 +197,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
index f65bf2d3caea3..194c26f59da1f 100644
--- a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
+++ b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es5.js
@@ -45,8 +45,8 @@ const o7 = {
 
 //// [O1.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -75,7 +75,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -95,8 +95,8 @@ var o1 = {
 };
 //// [O2.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -125,7 +125,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -152,8 +152,8 @@ var o2 = {
 };
 //// [O3.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -182,7 +182,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -209,8 +209,8 @@ var o3 = {
 };
 //// [O4.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -251,7 +251,7 @@ var __asyncDelegator = (this && this.__asyncDelegator) || function (o) {
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -289,8 +289,8 @@ var o4 = {
 };
 //// [O5.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -319,7 +319,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -377,8 +377,8 @@ var o5 = {
 };
 //// [O6.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -407,7 +407,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -433,8 +433,8 @@ var o6 = {
 };
 //// [O7.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -463,7 +463,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.forAwait(target=es2015).js b/tests/baselines/reference/emitter.forAwait(target=es2015).js
index 5e77358f5efab..1fe4ae6da47bd 100644
--- a/tests/baselines/reference/emitter.forAwait(target=es2015).js
+++ b/tests/baselines/reference/emitter.forAwait(target=es2015).js
@@ -136,7 +136,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -177,7 +177,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -257,7 +257,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -300,7 +300,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.forAwait(target=es2017).js b/tests/baselines/reference/emitter.forAwait(target=es2017).js
index 9477434034b60..76499a01b26fe 100644
--- a/tests/baselines/reference/emitter.forAwait(target=es2017).js
+++ b/tests/baselines/reference/emitter.forAwait(target=es2017).js
@@ -114,7 +114,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -155,7 +155,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -224,7 +224,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -267,7 +267,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/emitter.forAwait(target=es5).js b/tests/baselines/reference/emitter.forAwait(target=es5).js
index da767cdc76492..212f6b4eeb990 100644
--- a/tests/baselines/reference/emitter.forAwait(target=es5).js
+++ b/tests/baselines/reference/emitter.forAwait(target=es5).js
@@ -61,8 +61,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -147,8 +147,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -224,8 +224,8 @@ function f2() {
 }
 //// [file3.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -261,7 +261,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -314,8 +314,8 @@ function f3() {
 }
 //// [file4.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -351,7 +351,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -413,8 +413,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -491,8 +491,8 @@ function f5() {
 }
 //// [file6.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -528,7 +528,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
@@ -582,8 +582,8 @@ function f6() {
 }
 //// [file7.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -619,7 +619,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/es5-asyncFunction.js b/tests/baselines/reference/es5-asyncFunction.js
index df6b0627cd566..9b262e16c8844 100644
--- a/tests/baselines/reference/es5-asyncFunction.js
+++ b/tests/baselines/reference/es5-asyncFunction.js
@@ -21,8 +21,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/es5-asyncFunctionLongObjectLiteral.js b/tests/baselines/reference/es5-asyncFunctionLongObjectLiteral.js
index 76cbea45560a7..48fdc5eb3600e 100644
--- a/tests/baselines/reference/es5-asyncFunctionLongObjectLiteral.js
+++ b/tests/baselines/reference/es5-asyncFunctionLongObjectLiteral.js
@@ -41,8 +41,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/es5-importHelpersAsyncFunctions.js b/tests/baselines/reference/es5-importHelpersAsyncFunctions.js
index 472c206c08ef1..03a239f92195d 100644
--- a/tests/baselines/reference/es5-importHelpersAsyncFunctions.js
+++ b/tests/baselines/reference/es5-importHelpersAsyncFunctions.js
@@ -40,8 +40,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/exportDefaultFunctionInNamespace.js b/tests/baselines/reference/exportDefaultFunctionInNamespace.js
index 0ef66b3be8402..a0746a0e49282 100644
--- a/tests/baselines/reference/exportDefaultFunctionInNamespace.js
+++ b/tests/baselines/reference/exportDefaultFunctionInNamespace.js
@@ -21,8 +21,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/expressionsForbiddenInParameterInitializers.js b/tests/baselines/reference/expressionsForbiddenInParameterInitializers.js
index 851d68ec37295..986f220e6572f 100644
--- a/tests/baselines/reference/expressionsForbiddenInParameterInitializers.js
+++ b/tests/baselines/reference/expressionsForbiddenInParameterInitializers.js
@@ -20,8 +20,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/forAwaitPerIterationBindingDownlevel.js b/tests/baselines/reference/forAwaitPerIterationBindingDownlevel.js
index 0f14a1b85df58..b9d78e748190a 100644
--- a/tests/baselines/reference/forAwaitPerIterationBindingDownlevel.js
+++ b/tests/baselines/reference/forAwaitPerIterationBindingDownlevel.js
@@ -37,8 +37,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -67,7 +67,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/importAttributes7.js b/tests/baselines/reference/importAttributes7.js
index 66ff33e5bc507..30f45f2386d47 100644
--- a/tests/baselines/reference/importAttributes7.js
+++ b/tests/baselines/reference/importAttributes7.js
@@ -35,8 +35,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionAsyncES5AMD.js b/tests/baselines/reference/importCallExpressionAsyncES5AMD.js
index 44a3dcc0619ff..4a458837a45ac 100644
--- a/tests/baselines/reference/importCallExpressionAsyncES5AMD.js
+++ b/tests/baselines/reference/importCallExpressionAsyncES5AMD.js
@@ -41,8 +41,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionAsyncES5CJS.js b/tests/baselines/reference/importCallExpressionAsyncES5CJS.js
index a816ecf6e46d0..4f2657547fe75 100644
--- a/tests/baselines/reference/importCallExpressionAsyncES5CJS.js
+++ b/tests/baselines/reference/importCallExpressionAsyncES5CJS.js
@@ -42,8 +42,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionAsyncES5System.js b/tests/baselines/reference/importCallExpressionAsyncES5System.js
index f701d06d2d4b8..352be31696e94 100644
--- a/tests/baselines/reference/importCallExpressionAsyncES5System.js
+++ b/tests/baselines/reference/importCallExpressionAsyncES5System.js
@@ -43,8 +43,8 @@ System.register([], function (exports_1, context_1) {
         });
     };
     var __generator = (this && this.__generator) || function (thisArg, body) {
-        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-        return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+        return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
         function verb(n) { return function (v) { return step([n, v]); }; }
         function step(op) {
             if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionAsyncES5UMD.js b/tests/baselines/reference/importCallExpressionAsyncES5UMD.js
index 707b41f01ee3b..799fb08ad48dc 100644
--- a/tests/baselines/reference/importCallExpressionAsyncES5UMD.js
+++ b/tests/baselines/reference/importCallExpressionAsyncES5UMD.js
@@ -41,8 +41,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedAMD2.js b/tests/baselines/reference/importCallExpressionNestedAMD2.js
index 3200a5831d936..4f90f4e7732a2 100644
--- a/tests/baselines/reference/importCallExpressionNestedAMD2.js
+++ b/tests/baselines/reference/importCallExpressionNestedAMD2.js
@@ -25,8 +25,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedCJS2.js b/tests/baselines/reference/importCallExpressionNestedCJS2.js
index a40cf58f67480..5d2371ea723d5 100644
--- a/tests/baselines/reference/importCallExpressionNestedCJS2.js
+++ b/tests/baselines/reference/importCallExpressionNestedCJS2.js
@@ -23,8 +23,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedES20152.js b/tests/baselines/reference/importCallExpressionNestedES20152.js
index 7d52515fd233b..07e9f0ced120e 100644
--- a/tests/baselines/reference/importCallExpressionNestedES20152.js
+++ b/tests/baselines/reference/importCallExpressionNestedES20152.js
@@ -21,8 +21,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedES20202.js b/tests/baselines/reference/importCallExpressionNestedES20202.js
index 619b9b105a5c0..999f8ce28e6be 100644
--- a/tests/baselines/reference/importCallExpressionNestedES20202.js
+++ b/tests/baselines/reference/importCallExpressionNestedES20202.js
@@ -22,8 +22,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedSystem2.js b/tests/baselines/reference/importCallExpressionNestedSystem2.js
index 62dc40ce6ac20..1490a4690022d 100644
--- a/tests/baselines/reference/importCallExpressionNestedSystem2.js
+++ b/tests/baselines/reference/importCallExpressionNestedSystem2.js
@@ -31,8 +31,8 @@ System.register([], function (exports_1, context_1) {
         });
     };
     var __generator = (this && this.__generator) || function (thisArg, body) {
-        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-        return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+        return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
         function verb(n) { return function (v) { return step([n, v]); }; }
         function step(op) {
             if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNestedUMD2.js b/tests/baselines/reference/importCallExpressionNestedUMD2.js
index 812cf0aa1c62f..c74e8d9eda23e 100644
--- a/tests/baselines/reference/importCallExpressionNestedUMD2.js
+++ b/tests/baselines/reference/importCallExpressionNestedUMD2.js
@@ -33,8 +33,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importCallExpressionNoModuleKindSpecified.js b/tests/baselines/reference/importCallExpressionNoModuleKindSpecified.js
index 08338407d4134..e7bf6909ce642 100644
--- a/tests/baselines/reference/importCallExpressionNoModuleKindSpecified.js
+++ b/tests/baselines/reference/importCallExpressionNoModuleKindSpecified.js
@@ -55,8 +55,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importMeta(module=commonjs,target=es5).js b/tests/baselines/reference/importMeta(module=commonjs,target=es5).js
index f2728bb75ae20..6d5e4033ca07c 100644
--- a/tests/baselines/reference/importMeta(module=commonjs,target=es5).js
+++ b/tests/baselines/reference/importMeta(module=commonjs,target=es5).js
@@ -50,8 +50,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importMeta(module=es2020,target=es5).js b/tests/baselines/reference/importMeta(module=es2020,target=es5).js
index 7cdf12ba8fe0a..03e7011012f38 100644
--- a/tests/baselines/reference/importMeta(module=es2020,target=es5).js
+++ b/tests/baselines/reference/importMeta(module=es2020,target=es5).js
@@ -49,8 +49,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importMeta(module=esnext,target=es5).js b/tests/baselines/reference/importMeta(module=esnext,target=es5).js
index 7cdf12ba8fe0a..03e7011012f38 100644
--- a/tests/baselines/reference/importMeta(module=esnext,target=es5).js
+++ b/tests/baselines/reference/importMeta(module=esnext,target=es5).js
@@ -49,8 +49,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/importMeta(module=system,target=es5).js b/tests/baselines/reference/importMeta(module=system,target=es5).js
index 2be9428dee726..b854483f66f5c 100644
--- a/tests/baselines/reference/importMeta(module=system,target=es5).js
+++ b/tests/baselines/reference/importMeta(module=system,target=es5).js
@@ -51,8 +51,8 @@ System.register([], function (exports_1, context_1) {
         });
     };
     var __generator = (this && this.__generator) || function (thisArg, body) {
-        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-        return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+        var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+        return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
         function verb(n) { return function (v) { return step([n, v]); }; }
         function step(op) {
             if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/invalidContinueInDownlevelAsync.js b/tests/baselines/reference/invalidContinueInDownlevelAsync.js
index 1bf7a7a88e549..7aa96b7fc6c1c 100644
--- a/tests/baselines/reference/invalidContinueInDownlevelAsync.js
+++ b/tests/baselines/reference/invalidContinueInDownlevelAsync.js
@@ -21,8 +21,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/jsFileCompilationAwaitModifier.js b/tests/baselines/reference/jsFileCompilationAwaitModifier.js
index 148037d7006df..92361660afc56 100644
--- a/tests/baselines/reference/jsFileCompilationAwaitModifier.js
+++ b/tests/baselines/reference/jsFileCompilationAwaitModifier.js
@@ -23,8 +23,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/jsxElementType.js b/tests/baselines/reference/jsxElementType.js
index b2864d2740ce0..6d8349d54728a 100644
--- a/tests/baselines/reference/jsxElementType.js
+++ b/tests/baselines/reference/jsxElementType.js
@@ -141,8 +141,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/labeledStatementWithLabel.js b/tests/baselines/reference/labeledStatementWithLabel.js
index ba62abb97dbf1..f384e217dbb20 100644
--- a/tests/baselines/reference/labeledStatementWithLabel.js
+++ b/tests/baselines/reference/labeledStatementWithLabel.js
@@ -27,8 +27,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/legacyNodeModulesExportsSpecifierGenerationConditions.js b/tests/baselines/reference/legacyNodeModulesExportsSpecifierGenerationConditions.js
index b78501533ba4c..b942776c84403 100644
--- a/tests/baselines/reference/legacyNodeModulesExportsSpecifierGenerationConditions.js
+++ b/tests/baselines/reference/legacyNodeModulesExportsSpecifierGenerationConditions.js
@@ -43,8 +43,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/neverAsDiscriminantType(strict=false).js b/tests/baselines/reference/neverAsDiscriminantType(strict=false).js
index df00f302ae753..61e0670ff721d 100644
--- a/tests/baselines/reference/neverAsDiscriminantType(strict=false).js
+++ b/tests/baselines/reference/neverAsDiscriminantType(strict=false).js
@@ -79,8 +79,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/neverAsDiscriminantType(strict=true).js b/tests/baselines/reference/neverAsDiscriminantType(strict=true).js
index df00f302ae753..61e0670ff721d 100644
--- a/tests/baselines/reference/neverAsDiscriminantType(strict=true).js
+++ b/tests/baselines/reference/neverAsDiscriminantType(strict=true).js
@@ -79,8 +79,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/objectRestSpread.js b/tests/baselines/reference/objectRestSpread.js
index 5908b8d2d419e..a689b3f57614a 100644
--- a/tests/baselines/reference/objectRestSpread.js
+++ b/tests/baselines/reference/objectRestSpread.js
@@ -40,7 +40,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/operationsAvailableOnPromisedType.js b/tests/baselines/reference/operationsAvailableOnPromisedType.js
index 8ba23a7a47c6e..c84b83aed12d3 100644
--- a/tests/baselines/reference/operationsAvailableOnPromisedType.js
+++ b/tests/baselines/reference/operationsAvailableOnPromisedType.js
@@ -42,8 +42,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/parenthesizedAsyncArrowFunction.js b/tests/baselines/reference/parenthesizedAsyncArrowFunction.js
index 522b34f977925..e4fd9b3826362 100644
--- a/tests/baselines/reference/parenthesizedAsyncArrowFunction.js
+++ b/tests/baselines/reference/parenthesizedAsyncArrowFunction.js
@@ -18,8 +18,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/privateNamesIncompatibleModifiers.js b/tests/baselines/reference/privateNamesIncompatibleModifiers.js
index 6b6c916a43b37..7db58dd9ddb69 100644
--- a/tests/baselines/reference/privateNamesIncompatibleModifiers.js
+++ b/tests/baselines/reference/privateNamesIncompatibleModifiers.js
@@ -51,7 +51,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/promiseDefinitionTest.js b/tests/baselines/reference/promiseDefinitionTest.js
index f2d4d10dfe92e..ef7cd20fd9ef2 100644
--- a/tests/baselines/reference/promiseDefinitionTest.js
+++ b/tests/baselines/reference/promiseDefinitionTest.js
@@ -17,8 +17,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
index 6283c4097c898..b000368f44808 100644
--- a/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
+++ b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
@@ -176,8 +176,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/spreadOfParamsFromGeneratorMakesRequiredParams.js b/tests/baselines/reference/spreadOfParamsFromGeneratorMakesRequiredParams.js
index 429f2bf360800..18694bfa14cb4 100644
--- a/tests/baselines/reference/spreadOfParamsFromGeneratorMakesRequiredParams.js
+++ b/tests/baselines/reference/spreadOfParamsFromGeneratorMakesRequiredParams.js
@@ -10,8 +10,8 @@ call(function* (a: 'a') { }); // error, 2nd argument required
 
 //// [spreadOfParamsFromGeneratorMakesRequiredParams.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/templateStringWithEmbeddedYieldKeyword.js b/tests/baselines/reference/templateStringWithEmbeddedYieldKeyword.js
index 9165eaf7d05d0..3c767adb91b29 100644
--- a/tests/baselines/reference/templateStringWithEmbeddedYieldKeyword.js
+++ b/tests/baselines/reference/templateStringWithEmbeddedYieldKeyword.js
@@ -9,8 +9,8 @@ function* gen {
 
 //// [templateStringWithEmbeddedYieldKeyword.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/transformNestedGeneratorsWithTry.js b/tests/baselines/reference/transformNestedGeneratorsWithTry.js
index fafab23513f62..03e601481e87c 100644
--- a/tests/baselines/reference/transformNestedGeneratorsWithTry.js
+++ b/tests/baselines/reference/transformNestedGeneratorsWithTry.js
@@ -34,8 +34,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/usingDeclarations.1(target=es2015).js b/tests/baselines/reference/usingDeclarations.1(target=es2015).js
index a32dd5c254fb5..e007092478438 100644
--- a/tests/baselines/reference/usingDeclarations.1(target=es2015).js
+++ b/tests/baselines/reference/usingDeclarations.1(target=es2015).js
@@ -219,7 +219,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/usingDeclarations.1(target=es2017).js b/tests/baselines/reference/usingDeclarations.1(target=es2017).js
index afc9c8a3d9d92..6759e29ae4561 100644
--- a/tests/baselines/reference/usingDeclarations.1(target=es2017).js
+++ b/tests/baselines/reference/usingDeclarations.1(target=es2017).js
@@ -210,7 +210,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/usingDeclarations.1(target=es5).js b/tests/baselines/reference/usingDeclarations.1(target=es5).js
index 96d3e7e0311e7..d9a8c2e561e93 100644
--- a/tests/baselines/reference/usingDeclarations.1(target=es5).js
+++ b/tests/baselines/reference/usingDeclarations.1(target=es5).js
@@ -179,8 +179,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
@@ -261,7 +261,7 @@ var __await = (this && this.__await) || function (v) { return this instanceof __
 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 || []), i, q = [];
-    return i = {}, verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
+    return i = Object.create((typeof AsyncIterator === "function" ? AsyncIterator : Object).prototype), verb("next"), verb("throw"), verb("return", awaitReturn), i[Symbol.asyncIterator] = function () { return this; }, i;
     function awaitReturn(f) { return function (v) { return Promise.resolve(v).then(f, reject); }; }
     function verb(n, f) { if (g[n]) { i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; if (f) i[n] = f(i[n]); } }
     function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
diff --git a/tests/baselines/reference/usingDeclarationsInForAwaitOf(target=es5).js b/tests/baselines/reference/usingDeclarationsInForAwaitOf(target=es5).js
index 73e60e2988694..31d3c5ab036bb 100644
--- a/tests/baselines/reference/usingDeclarationsInForAwaitOf(target=es5).js
+++ b/tests/baselines/reference/usingDeclarationsInForAwaitOf(target=es5).js
@@ -18,8 +18,8 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");
diff --git a/tests/baselines/reference/yieldInForInInDownlevelGenerator.js b/tests/baselines/reference/yieldInForInInDownlevelGenerator.js
index 205d535ba8569..db5011137f0fc 100644
--- a/tests/baselines/reference/yieldInForInInDownlevelGenerator.js
+++ b/tests/baselines/reference/yieldInForInInDownlevelGenerator.js
@@ -12,8 +12,8 @@ function* gen() {
 
 //// [yieldInForInInDownlevelGenerator.js]
 var __generator = (this && this.__generator) || function (thisArg, body) {
-    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
-    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g = Object.create((typeof Iterator === "function" ? Iterator : Object).prototype);
+    return g.next = verb(0), g["throw"] = verb(1), g["return"] = verb(2), typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
     function verb(n) { return function (v) { return step([n, v]); }; }
     function step(op) {
         if (f) throw new TypeError("Generator is already executing.");

From 9c3f1c6c84185a1b69435ee3a7730aaa79cfcf32 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Fri, 2 Aug 2024 11:51:53 -0400
Subject: [PATCH 2/2] Fix format

---
 src/testRunner/unittests/evaluation/asyncGenerator.ts | 2 +-
 src/testRunner/unittests/evaluation/generator.ts      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/testRunner/unittests/evaluation/asyncGenerator.ts b/src/testRunner/unittests/evaluation/asyncGenerator.ts
index e7fb37f26e496..bcfff9215b0db 100644
--- a/src/testRunner/unittests/evaluation/asyncGenerator.ts
+++ b/src/testRunner/unittests/evaluation/asyncGenerator.ts
@@ -84,7 +84,7 @@ describe("unittests:: evaluation:: asyncGeneratorEvaluation", () => {
         ]);
     });
     it("Supports global `AsyncIterator.prototype` if present", () => {
-        class AsyncIterator { }
+        class AsyncIterator {}
         const { gen } = evaluator.evaluateTypeScript(
             `
             export async function * gen() {}
diff --git a/src/testRunner/unittests/evaluation/generator.ts b/src/testRunner/unittests/evaluation/generator.ts
index 7d569772e0d23..4b1e3a1ffd319 100644
--- a/src/testRunner/unittests/evaluation/generator.ts
+++ b/src/testRunner/unittests/evaluation/generator.ts
@@ -40,7 +40,7 @@ describe("unittests:: evaluation:: generatorEvaluation", () => {
         assert.deepEqual(output, []);
     });
     it("Supports global `Iterator.prototype` if present", () => {
-        class Iterator { }
+        class Iterator {}
         const { gen } = evaluator.evaluateTypeScript(
             `
             export function * gen() {}