michael@0: function f(arr, v)
michael@0: {
michael@0:   arr.push(v);
michael@0: }
michael@0: 
michael@0: function basic(out)
michael@0: {
michael@0:   // Use a much-greater capacity than the eventual non-writable length.
michael@0:   var a = out.a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];
michael@0:   Object.defineProperty(a, "length", { writable: false, value: 6 });
michael@0: 
michael@0:   f(a, 99);
michael@0: }
michael@0: 
michael@0: var obj = {};
michael@0: var a;
michael@0: 
michael@0: try
michael@0: {
michael@0:   basic(obj);
michael@0:   throw new Error("didn't throw!");
michael@0: }
michael@0: catch (e)
michael@0: {
michael@0:   assertEq(e instanceof TypeError, true, "expected TypeError, got " + e);
michael@0: 
michael@0:   a = obj.a;
michael@0:   assertEq(a.hasOwnProperty(6), false);
michael@0:   assertEq(a[6], undefined);
michael@0:   assertEq(a.length, 6);
michael@0: }