diff --git a/src/services/services.ts b/src/services/services.ts
index 14f7afd52ca..c8b947161b2 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1927,16 +1927,14 @@ module ts {
         });
     }
 
-    export function createLanguageService(host: LanguageServiceHost, documentRegistry: DocumentRegistry): LanguageService {
+    export function createLanguageService(host: LanguageServiceHost, documentRegistry: DocumentRegistry = createDocumentRegistry()): LanguageService {
         var syntaxTreeCache: SyntaxTreeCache = new SyntaxTreeCache(host);
         var ruleProvider: formatting.RulesProvider;
         var program: Program;
 
         // this checker is used to answer all LS questions except errors 
         var typeInfoResolver: TypeChecker;
-
         var useCaseSensitivefilenames = false;
-        var documentRegistry = documentRegistry;
         var cancellationToken = new CancellationTokenObject(host.getCancellationToken && host.getCancellationToken());
         var activeCompletionSession: CompletionSession;         // The current active completion session, used to get the completion entry details