diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 2eb472ebdf0..95878917b3d 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -1440,7 +1440,7 @@ namespace ts {
             : node;
     }
 
-    export function createInterfaceDeclaration(decorators: Decorator[] | undefined, modifiers: Modifier[] | undefined, name: string | Identifier | undefined, typeParameters: TypeParameterDeclaration[] | undefined, heritageClauses: HeritageClause[], members: TypeElement[]) {
+    export function createInterfaceDeclaration(decorators: Decorator[] | undefined, modifiers: Modifier[] | undefined, name: string | Identifier, typeParameters: TypeParameterDeclaration[] | undefined, heritageClauses: HeritageClause[] | undefined, members: TypeElement[]) {
         const node = <InterfaceDeclaration>createSynthesizedNode(SyntaxKind.InterfaceDeclaration);
         node.decorators = asNodeArray(decorators);
         node.modifiers = asNodeArray(modifiers);
@@ -1451,7 +1451,7 @@ namespace ts {
         return node;
     }
 
-    export function updateInterfaceDeclaration(node: InterfaceDeclaration, decorators: Decorator[] | undefined, modifiers: Modifier[] | undefined, name: Identifier | undefined, typeParameters: TypeParameterDeclaration[] | undefined, heritageClauses: HeritageClause[], members: TypeElement[]) {
+    export function updateInterfaceDeclaration(node: InterfaceDeclaration, decorators: Decorator[] | undefined, modifiers: Modifier[] | undefined, name: Identifier, typeParameters: TypeParameterDeclaration[] | undefined, heritageClauses: HeritageClause[] | undefined, members: TypeElement[]) {
         return node.decorators !== decorators
             || node.modifiers !== modifiers
             || node.name !== name