Fix compile issues with -std=c++11

This compiles with -std=c++11:
message Foo {
  map<string, Foo> value = 1;
}

This does not compile:
message Foo {
  map<int32, Foo> value = 1;
}

Needs to dig more into the underlying issue.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/google/protobuf/map_test.cc b/src/google/protobuf/map_test.cc
index a74801d9..16a24c25 100644
--- a/src/google/protobuf/map_test.cc
+++ b/src/google/protobuf/map_test.cc
@@ -2188,7 +2188,7 @@ TEST_F(MapFieldInDynamicMessageTest, MapSpaceUsed) {
 
 TEST_F(MapFieldInDynamicMessageTest, RecursiveMap) {
   TestRecursiveMapMessage from;
-  (*from.mutable_a())[0];
+  (*from.mutable_a())[""];
   string data = from.SerializeAsString();
   google::protobuf::scoped_ptr<Message> to(
       factory_.GetPrototype(recursive_map_descriptor_)->New());