The Tor Browser / file revision

 x = [1,2,3];

 setObjectMetadata(x, {y:0});

 assertEq(getObjectMetadata(x).y, 0);

 setObjectMetadataCallback(true);

 function Foo() {

   this.x = 0;

   this.y = 1;

 }

 function hello() {

   function there() {

     w = new Foo();

     x = [1,2,3];

     y = [2,3,5];

     z = {a:0,b:1};

   }

   callee = there;

   callee();

 }

 hello();

 var wc = getObjectMetadata(w).index;

 var xc = getObjectMetadata(x).index;

 var yc = getObjectMetadata(y).index;

 var zc = getObjectMetadata(z).index;

 assertEq(xc > wc, true);

 assertEq(yc > xc, true);

 assertEq(zc > yc, true);

 assertEq(getObjectMetadata(x).stack[0], callee);

 assertEq(getObjectMetadata(x).stack[1], hello);