diff --git a/src/google/protobuf/map.h b/src/google/protobuf/map.h
index f99c5a7318..a9937b9b96 100644
--- a/src/google/protobuf/map.h
+++ b/src/google/protobuf/map.h
@@ -119,7 +119,7 @@ class MapIterator {
  private:
   typename hash_map<Key, value_type*>::iterator it_;
 
-  friend Map<Key, T>;
+  friend class Map<Key, T>;
 };
 
 // google::protobuf::Map is an associative container type used to store protobuf map