Version 3.1.3....

test/mjsunit/json.js

 // Copyright 2009 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 397 matching lines @@
                        valueOf: function() { return true; } };
 oddball2.__proto__ = { __proto__: null,
                        toJSON: function () { return oddball3; } }
 assertEquals('"true"', JSON.stringify(oddball2));
 
 
 var falseNum = Object("37");
 falseNum.__proto__ = Number.prototype;
 falseNum.toString = function() { return 42; };
 assertEquals('"42"', JSON.stringify(falseNum));
+
+// We don't currently allow plain properties called __proto__ in JSON
+// objects in JSON.parse. Instead we read them as we would JS object
+// literals. If we change that, this test should change with it.
+// 
+// Parse a non-object value as __proto__. This must not create a 
+// __proto__ property different from the original, and should not 
+// change the original.
+var o = JSON.parse('{"__proto__":5}');
+assertEquals(Object.prototype, o.__proto__);  // __proto__ isn't changed.
+assertEquals(0, Object.keys(o).length);  // __proto__ isn't added as enumerable.
+
+
+