diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 0c1c0acd474..7c842de277f 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -67,7 +67,7 @@ namespace ts {
         let errorNameNode: DeclarationName;
         const emitJsDocComments = compilerOptions.removeComments ? noop : writeJsDocComments;
         const emit = compilerOptions.stripInternal ? stripInternal : emitNode;
-        let noDeclare: boolean;
+        let needsDeclare = true;
 
         let moduleElementDeclarationEmitInfo: ModuleElementDeclarationEmitInfo[] = [];
         let asynchronousSubModuleDeclarationEmitInfo: ModuleElementDeclarationEmitInfo[];
@@ -110,11 +110,11 @@ namespace ts {
 
             resultHasExternalModuleIndicator = false;
             if (!isBundledEmit || !isExternalModule(sourceFile)) {
-                noDeclare = false;
+                needsDeclare = true;
                 emitSourceFile(sourceFile);
             }
             else if (isExternalModule(sourceFile)) {
-                noDeclare = true;
+                needsDeclare = false;
                 write(`declare module "${getResolvedExternalModuleName(host, sourceFile)}" {`);
                 writeLine();
                 increaseIndent();
@@ -612,9 +612,9 @@ namespace ts {
             }
         }
 
-        function emitTempVariableDeclaration(expr: Expression, baseName: string, diagnostic: SymbolAccessibilityDiagnostic): string {
+        function emitTempVariableDeclaration(expr: Expression, baseName: string, diagnostic: SymbolAccessibilityDiagnostic, needsDeclare: boolean): string {
             const tempVarName = getExportTempVariableName(baseName);
-            if (!noDeclare) {
+            if (needsDeclare) {
                 write("declare ");
             }
             write("const ");
@@ -636,7 +636,7 @@ namespace ts {
                 const tempVarName = emitTempVariableDeclaration(node.expression, "_default", {
                     diagnosticMessage: Diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
                     errorNode: node
-                });
+                }, needsDeclare);
                 write(node.isExportEquals ? "export = " : "export default ");
                 write(tempVarName);
             }
@@ -728,7 +728,7 @@ namespace ts {
                 if (modifiers & ModifierFlags.Default) {
                     write("default ");
                 }
-                else if (node.kind !== SyntaxKind.InterfaceDeclaration && !noDeclare) {
+                else if (node.kind !== SyntaxKind.InterfaceDeclaration && needsDeclare) {
                     write("declare ");
                 }
             }
@@ -1155,7 +1155,7 @@ namespace ts {
                         diagnosticMessage: Diagnostics.extends_clause_of_exported_class_0_has_or_is_using_private_name_1,
                         errorNode: baseTypeNode,
                         typeName: node.name
-                    });
+                    }, !findAncestor(node, n => n.kind === SyntaxKind.ModuleDeclaration));
             }
 
             emitJsDocComments(node);
diff --git a/tests/baselines/reference/declarationEmitExpressionInExtends5.js b/tests/baselines/reference/declarationEmitExpressionInExtends5.js
new file mode 100644
index 00000000000..77f8fc0e12c
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitExpressionInExtends5.js
@@ -0,0 +1,67 @@
+//// [declarationEmitExpressionInExtends5.ts]
+namespace Test
+{
+	export interface IFace
+	{
+	}
+
+	export class SomeClass implements IFace
+	{
+	}
+
+	export class Derived extends getClass<IFace>()
+	{
+	}
+
+	export function getClass<T>() : new() => T
+	{
+		return SomeClass as (new() => T);
+	}
+}
+
+
+//// [declarationEmitExpressionInExtends5.js]
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var Test;
+(function (Test) {
+    var SomeClass = (function () {
+        function SomeClass() {
+        }
+        return SomeClass;
+    }());
+    Test.SomeClass = SomeClass;
+    var Derived = (function (_super) {
+        __extends(Derived, _super);
+        function Derived() {
+            return _super !== null && _super.apply(this, arguments) || this;
+        }
+        return Derived;
+    }(getClass()));
+    Test.Derived = Derived;
+    function getClass() {
+        return SomeClass;
+    }
+    Test.getClass = getClass;
+})(Test || (Test = {}));
+
+
+//// [declarationEmitExpressionInExtends5.d.ts]
+declare namespace Test {
+    interface IFace {
+    }
+    class SomeClass implements IFace {
+    }
+    const Derived_base: new () => IFace;
+    class Derived extends Derived_base {
+    }
+    function getClass<T>(): new () => T;
+}
diff --git a/tests/baselines/reference/declarationEmitExpressionInExtends5.symbols b/tests/baselines/reference/declarationEmitExpressionInExtends5.symbols
new file mode 100644
index 00000000000..42bf5892211
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitExpressionInExtends5.symbols
@@ -0,0 +1,33 @@
+=== tests/cases/compiler/declarationEmitExpressionInExtends5.ts ===
+namespace Test
+>Test : Symbol(Test, Decl(declarationEmitExpressionInExtends5.ts, 0, 0))
+{
+	export interface IFace
+>IFace : Symbol(IFace, Decl(declarationEmitExpressionInExtends5.ts, 1, 1))
+	{
+	}
+
+	export class SomeClass implements IFace
+>SomeClass : Symbol(SomeClass, Decl(declarationEmitExpressionInExtends5.ts, 4, 2))
+>IFace : Symbol(IFace, Decl(declarationEmitExpressionInExtends5.ts, 1, 1))
+	{
+	}
+
+	export class Derived extends getClass<IFace>()
+>Derived : Symbol(Derived, Decl(declarationEmitExpressionInExtends5.ts, 8, 2))
+>getClass : Symbol(getClass, Decl(declarationEmitExpressionInExtends5.ts, 12, 2))
+>IFace : Symbol(IFace, Decl(declarationEmitExpressionInExtends5.ts, 1, 1))
+	{
+	}
+
+	export function getClass<T>() : new() => T
+>getClass : Symbol(getClass, Decl(declarationEmitExpressionInExtends5.ts, 12, 2))
+>T : Symbol(T, Decl(declarationEmitExpressionInExtends5.ts, 14, 26))
+>T : Symbol(T, Decl(declarationEmitExpressionInExtends5.ts, 14, 26))
+	{
+		return SomeClass as (new() => T);
+>SomeClass : Symbol(SomeClass, Decl(declarationEmitExpressionInExtends5.ts, 4, 2))
+>T : Symbol(T, Decl(declarationEmitExpressionInExtends5.ts, 14, 26))
+	}
+}
+
diff --git a/tests/baselines/reference/declarationEmitExpressionInExtends5.types b/tests/baselines/reference/declarationEmitExpressionInExtends5.types
new file mode 100644
index 00000000000..22aafb85e58
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitExpressionInExtends5.types
@@ -0,0 +1,35 @@
+=== tests/cases/compiler/declarationEmitExpressionInExtends5.ts ===
+namespace Test
+>Test : typeof Test
+{
+	export interface IFace
+>IFace : IFace
+	{
+	}
+
+	export class SomeClass implements IFace
+>SomeClass : SomeClass
+>IFace : IFace
+	{
+	}
+
+	export class Derived extends getClass<IFace>()
+>Derived : Derived
+>getClass<IFace>() : IFace
+>getClass : <T>() => new () => T
+>IFace : IFace
+	{
+	}
+
+	export function getClass<T>() : new() => T
+>getClass : <T>() => new () => T
+>T : T
+>T : T
+	{
+		return SomeClass as (new() => T);
+>SomeClass as (new() => T) : new () => T
+>SomeClass : typeof SomeClass
+>T : T
+	}
+}
+
diff --git a/tests/cases/compiler/declarationEmitExpressionInExtends5.ts b/tests/cases/compiler/declarationEmitExpressionInExtends5.ts
new file mode 100644
index 00000000000..5057ade7570
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitExpressionInExtends5.ts
@@ -0,0 +1,20 @@
+// @declaration: true
+namespace Test
+{
+	export interface IFace
+	{
+	}
+
+	export class SomeClass implements IFace
+	{
+	}
+
+	export class Derived extends getClass<IFace>()
+	{
+	}
+
+	export function getClass<T>() : new() => T
+	{
+		return SomeClass as (new() => T);
+	}
+}