/js/src/jit-test/tests/basic/testDecElem2.js

 1var obj = {s: ""};
 2var name = "s";
 3var a = [];
 4for (var i = 0; i <= 13; i++) {
 5    a[i] = 'x';
 6    if (i > 8)
 7        a[i] = --obj[name];  // first recording changes obj.s from string to number
 8}
 9assertEq(a.join(','), Array(10).join('x,') + '-1,-2,-3,-4,-5');
10assertEq(obj.s, -5);
11