Correctly load message from an Error object.

src/messages.js

 // 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 1229 matching lines @@
 $Error.captureStackTrace = captureStackTrace;
 
 %SetProperty($Error.prototype, 'message', '', DONT_ENUM);
 
 // Global list of error objects visited during ErrorToString. This is
 // used to detect cycles in error toString formatting.
 var visited_errors = new InternalArray();
 var cyclic_error_marker = new $Object();
 
 function GetPropertyWithoutInvokingMonkeyGetters(error, name) {
+  var current = error;
   // Climb the prototype chain until we find the holder.
-  while (error && !%HasLocalProperty(error, name)) {
-    error = %GetPrototype(error);
+  while (current && !%HasLocalProperty(current, name)) {
+    current = %GetPrototype(current);
   }
-  if (IS_NULL(error)) return UNDEFINED;
-  if (!IS_OBJECT(error)) return error[name];
+  if (IS_NULL(current)) return UNDEFINED;
+  if (!IS_OBJECT(current)) return error[name];
   // If the property is an accessor on one of the predefined errors that can be
   // generated statically by the compiler, don't touch it. This is to address
   // http://code.google.com/p/chromium/issues/detail?id=69187
-  var desc = %GetOwnProperty(error, name);
+  var desc = %GetOwnProperty(current, name);
   if (desc && desc[IS_ACCESSOR_INDEX]) {
     var isName = name === "name";
-    if (error === $ReferenceError.prototype)
+    if (current === $ReferenceError.prototype)
       return isName ? "ReferenceError" : UNDEFINED;
-    if (error === $SyntaxError.prototype)
+    if (current === $SyntaxError.prototype)
       return isName ? "SyntaxError" : UNDEFINED;
-    if (error === $TypeError.prototype)
+    if (current === $TypeError.prototype)
       return isName ? "TypeError" : UNDEFINED;
   }
   // Otherwise, read normally.
   return error[name];
 }
 
 function ErrorToStringDetectCycle(error) {
   if (!%PushIfAbsent(visited_errors, error)) throw cyclic_error_marker;
   try {
     var name = GetPropertyWithoutInvokingMonkeyGetters(error, "name");
@@ skipping 64 matching lines @@
     %GetAndClearOverflowedStackTrace(this);
   };
 
   %DefineOrRedefineAccessorProperty(
       boilerplate, 'stack', getter, setter, DONT_ENUM);
 
   return boilerplate;
 }
 
 var kStackOverflowBoilerplate = SetUpStackOverflowBoilerplate();