Fix generalization with callbacks.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2602 matching lines @@
     PropertyDetails details = descriptors->GetDetails(i);
     PropertyDetails target_details =
         current->instance_descriptors()->GetDetails(i);
     if (details.attributes() != target_details.attributes()) return NULL;
     if (details.type() == CALLBACKS) {
       if (target_details.type() != CALLBACKS) return NULL;
       if (descriptors->GetValue(i) !=
               current->instance_descriptors()->GetValue(i)) {
         return NULL;
       }
+    } else if (target_details.type() == CALLBACKS) {
+      return NULL;
     }
   }
 
   return current;
 }
 
 
 Map* Map::FindLastMatchMap(int verbatim,
                            int length,
                            DescriptorArray* descriptors) {
@@ skipping 13845 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal