michael@0: 
michael@0: function foo(x, y) {
michael@0:   var res = 0;
michael@0:   for (var i = 0; i < 10; i++) {
michael@0:     res += x.f + y[i];
michael@0:   }
michael@0:   return res;
michael@0: }
michael@0: 
michael@0: var x = {f:0};
michael@0: var y = Array(10);
michael@0: for (var i = 0; i < 10; i++) {
michael@0:   if (i == 5)
michael@0:     Object.defineProperty(Object.prototype, 5, {get: function() { x.f = 10; return 5}});
michael@0:   else
michael@0:     y[i] = i;
michael@0: }
michael@0: 
michael@0: assertEq(foo(x, y), 85);