michael@0: function f(x) {
michael@0:     var s = "a";
michael@0:     var last = "";
michael@0:     for (var i = 0; i < 10; i++) {
michael@0:         last = s[x];
michael@0:     }
michael@0:     return last;
michael@0: }
michael@0: 
michael@0: f(0);
michael@0: 
michael@0: assertEq(f(1), undefined);