michael@0: function f() {
michael@0:     var a = [];
michael@0:     for (var i = 0; i < 1000; i++) {
michael@0:       a.x = {}
michael@0:     }
michael@0:     a[i][0] = 0;
michael@0: }
michael@0: 
michael@0: var e;
michael@0: try {
michael@0:     f();
michael@0: } catch (error) {e = error;}
michael@0: assertEq(e.toString(), 'TypeError: a[i] is undefined');