diff --git a/modules/angular2/globals.d.ts b/modules/angular2/globals.d.ts
index 7a881d0fa1..d6b18a7845 100644
--- a/modules/angular2/globals.d.ts
+++ b/modules/angular2/globals.d.ts
@@ -9,7 +9,9 @@ declare type int = number;
 
 interface List<T> extends Array<T> {}
 
-interface StringMap<K, V> extends Object {}
+// FIXME: K must be string!
+// FIXME: should have an index signature, `[k: string]: V;`
+interface StringMap<K, V> {}
 
 interface BrowserNodeGlobal {
   Object: typeof Object;