The Tor Browser / file revision

 var o2 = Proxy.create({});

 function f1() {}

 function f2() {}

 function f4(o) {

     var key = Object.getOwnPropertyNames(o)[18];

     o4 = o[key];

     o.prototype = {};

 }

 f4(f1);

 f4(f1);

 f4(f2);

 new f2(o2);

 // these will hold only if type inference is enabled.

 //assertEq(shapeOf(f1) == shapeOf(f2), false);

 //assertEq(shapeOf(f1) == shapeOf(f4), false);

 function factory() {

   function foo() {}

   foo.x = 0;

   return foo;

 }

 var fobjs = [];

 for (var i = 0; i < 10; i++) {

   var of = fobjs[i] = factory();

   if (i > 0) {

     assertEq(fobjs[i - 1] === of, false);

     assertEq(shapeOf(fobjs[i - 1]), shapeOf(of));

   }

 }

 assertEq(shapeOf(fobjs[0]) == shapeOf(f1), false);