Ensure a type-error is thrown when trying to assign to a readonly property on the global scope.

src/ic.cc

 // Copyright 2012 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 1445 matching lines @@
       TRACE_IC("StoreIC", name, state, *stub);
     }
     return receiver->SetProperty(*name, *value, NONE, strict_mode, store_mode);
   }
 
   LookupResult lookup(isolate());
   if (LookupForWrite(receiver, name, &lookup)) {
     if (FLAG_use_ic) {
       UpdateStoreCaches(&lookup, state, strict_mode, receiver, name, value);
     }
-  } else if (strict_mode == kStrictMode && IsUndeclaredGlobal(object)) {
+  } else if (strict_mode == kStrictMode &&
+             !(lookup.IsProperty() && lookup.IsReadOnly()) &&
+             IsUndeclaredGlobal(object)) {
     // Strict mode doesn't allow setting non-existent global property.
     return ReferenceError("not_defined", name);
   }
 
   // Set the property.
   return receiver->SetProperty(*name, *value, NONE, strict_mode, store_mode);
 }
 
 
 void StoreIC::UpdateStoreCaches(LookupResult* lookup,
@@ skipping 1193 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal