Optimize Object.seal and Object.preventExtensions

test/mjsunit/object-freeze.js

 // Copyright 2010 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 321 matching lines @@
 assertThrows(function() { obj.splice(0,1,1); }, TypeError);
 assertTrue(Object.isFrozen(obj));
 
 // Verify that unshift() with no arguments will fail if it reifies from
 // the prototype into the object.
 obj = [1,,3];
 obj.__proto__[1] = 1;
 assertEquals(1, obj[1]);
 Object.freeze(obj);
 assertThrows(function() { obj.unshift(); }, TypeError);
+
+// Sealing and then Freezing should do the right thing.
+var obj = { foo: 'bar', 0: 'element' };
+Object.seal(obj);
+assertTrue(Object.isSealed(obj));
+assertFalse(Object.isFrozen(obj));
+Object.freeze(obj);
+assertTrue(Object.isSealed(obj));
+assertTrue(Object.isFrozen(obj));