Merge pull request #37283 from JoshuaKGoldberg/extends-constructor-typeerror

Added runtime TypeError for non-function, non-null __extends

src/compiler/factory/emitHelpers.ts

@@ -585,6 +585,8 @@ namespace ts {
                 };
 
                 return function (d, b) {
+                    if (typeof b !== "function" && b !== null)
+                        throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
                     extendStatics(d, b);
                     function __() { this.constructor = d; }
                     d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js

@@ -29,6 +29,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js

@@ -33,6 +33,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/abstractClassInLocalScope.js

@@ -16,6 +16,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/abstractClassInLocalScopeIsAbstract.js

@@ -16,6 +16,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/abstractProperty.js

@@ -30,6 +30,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/abstractPropertyInConstructor.js

@@ -80,6 +80,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/abstractPropertyNegative.js

@@ -52,6 +52,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/accessOverriddenBaseClassMember1.js

@@ -24,6 +24,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/accessorsOverrideProperty7.js

@@ -16,6 +16,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/accessors_spec_section-4.5_inference.js

@@ -33,6 +33,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInAccessorsOfClass.js

@@ -47,6 +47,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInArray.js

@@ -41,6 +41,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInFunctionExpression.js

@@ -40,6 +40,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInGenericFunction.js

@@ -44,6 +44,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInIndexerOfClass.js

@@ -46,6 +46,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInObjectLiteral.js

@@ -41,6 +41,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInOrExpression.js

@@ -44,6 +44,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInTypeArgumentOfExtendsClause.js

@@ -44,6 +44,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
@@ -70,6 +72,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/aliasUsageInVarAssignment.js

@@ -40,6 +40,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/ambiguousOverloadResolution.js

@@ -17,6 +17,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/amdDeclarationEmitNoExtraDeclare.js

@@ -30,6 +30,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/anonClassDeclarationEmitIsAnon.js

@@ -44,6 +44,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
@@ -84,6 +86,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/anonymousClassDeclarationDoesntPrintWithReadonly.js

@@ -17,6 +17,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/apparentTypeSubtyping.js

@@ -32,6 +32,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/apparentTypeSupertype.js

@@ -22,6 +22,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayAssignmentTest1.js

@@ -94,6 +94,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayAssignmentTest2.js

@@ -68,6 +68,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayBestCommonTypes.js

@@ -116,6 +116,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayLiteralTypeInference.js

@@ -60,6 +60,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayLiterals.js

@@ -46,6 +46,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayLiteralsWithRecursiveGenerics.js

@@ -34,6 +34,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.js

@@ -28,6 +28,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/arrowFunctionContexts.js

@@ -104,6 +104,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assertionTypePredicates1.js

@@ -206,6 +206,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithCallSignatures3.js

@@ -109,6 +109,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithCallSignatures4.js

@@ -108,6 +108,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithCallSignatures5.js

@@ -75,6 +75,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithCallSignatures6.js

@@ -52,6 +52,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithConstructSignatures3.js

@@ -109,6 +109,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithConstructSignatures4.js

@@ -108,6 +108,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithConstructSignatures5.js

@@ -75,6 +75,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithConstructSignatures6.js

@@ -52,6 +52,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithNumericIndexer.js

@@ -53,6 +53,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithNumericIndexer3.js

@@ -50,6 +50,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithObjectMembers4.js

@@ -101,6 +101,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithObjectMembersOptionality.js

@@ -98,6 +98,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithObjectMembersOptionality2.js

@@ -101,6 +101,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatWithStringIndexer.js

@@ -63,6 +63,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentCompatability45.js

@@ -17,6 +17,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/assignmentLHSIsValue.js

@@ -79,6 +79,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/asyncImportedPromise_es5.js

@@ -19,6 +19,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/autolift4.js

@@ -32,6 +32,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseCheck.js

@@ -38,6 +38,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseClassImprovedMismatchErrors.js

@@ -27,6 +27,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseConstraintOfDecorator.js

@@ -29,6 +29,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseExpressionTypeParameters.js

@@ -23,6 +23,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseIndexSignatureResolution.js

@@ -33,6 +33,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseTypeOrderChecking.js

@@ -45,6 +45,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/baseTypeWrappingInstantiationChain.js

@@ -36,6 +36,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/bases.js

@@ -29,6 +29,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/bestCommonTypeOfConditionalExpressions.js

@@ -37,6 +37,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/bestCommonTypeOfConditionalExpressions2.js

@@ -35,6 +35,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/bestCommonTypeOfTuple2.js

@@ -31,6 +31,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callChainWithSuper(target=es5).js

@@ -16,6 +16,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callSignatureAssignabilityInInheritance2.js

@@ -79,6 +79,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callSignatureAssignabilityInInheritance3.js

@@ -124,6 +124,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callSignatureAssignabilityInInheritance4.js

@@ -59,6 +59,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callSignatureAssignabilityInInheritance5.js

@@ -59,6 +59,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callSignatureAssignabilityInInheritance6.js

@@ -62,6 +62,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/callWithSpread.js

@@ -67,6 +67,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/captureSuperPropertyAccessInSuperCall01.js

@@ -20,6 +20,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/captureThisInSuperCall.js

@@ -17,6 +17,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/castingTuple.js

@@ -43,6 +43,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/chainedAssignment3.js

@@ -31,6 +31,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/chainedCallsWithTypeParameterConstrainedToOtherTypeParameter.js

@@ -28,6 +28,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkForObjectTooStrict.js

@@ -40,6 +40,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenCanBeTupleType.js

@@ -32,6 +32,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty12.js

@@ -42,6 +42,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty13.js

@@ -37,6 +37,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty14.js

@@ -52,6 +52,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty3.js

@@ -49,6 +49,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty4.js

@@ -54,6 +54,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty5.js

@@ -40,6 +40,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty6.js

@@ -53,6 +53,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty7.js

@@ -38,6 +38,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxChildrenProperty8.js

@@ -39,6 +39,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxIntersectionElementPropsType.js

@@ -22,6 +22,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkJsxSubtleSkipContextSensitiveBug.js

@@ -34,6 +34,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing1.js

@@ -19,6 +19,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing2.js

@@ -19,6 +19,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing3.js

@@ -24,6 +24,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing4.js

@@ -28,6 +28,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing5.js

@@ -16,6 +16,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing6.js

@@ -19,6 +19,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing7.js

@@ -18,6 +18,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/checkSuperCallBeforeThisAccessing8.js

@@ -19,6 +19,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/circularConstraintYieldsAppropriateError.js

@@ -26,6 +26,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/circularImportAlias.js

@@ -29,6 +29,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());

tests/baselines/reference/circularTypeofWithFunctionModule.js

@@ -22,6 +22,8 @@ var __extends = (this && this.__extends) || (function () {
         return extendStatics(d, b);
     };
     return function (d, b) {
+        if (typeof b !== "function" && b !== null)
+            throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
         extendStatics(d, b);
         function __() { this.constructor = d; }
         d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());