michael@0: var a = [1, 2, 3, 4];
michael@0: var count = 0;
michael@0: 
michael@0: function f(arr, i) {
michael@0:     arr[2] = i;
michael@0: }
michael@0: 
michael@0: for (var i=0; i<80; i++) {
michael@0:     f(a, i);
michael@0:     assertEq(a[2], i);
michael@0: }
michael@0: 
michael@0: delete a[2];
michael@0: f(a, 50);
michael@0: assertEq(a[2], 50);
michael@0: 
michael@0: Object.defineProperty(Object.prototype, "2", {
michael@0:     set: function() { count++; }
michael@0: });
michael@0: delete a[2];
michael@0: 
michael@0: f(a, 100);
michael@0: f(a, 100);
michael@0: 
michael@0: assertEq(a[2], undefined);
michael@0: assertEq(count, 2);