src/third_party/mozjs-45/js/src/jit-test/tests/for-of/arrays-shrinking-2.js

// Using shift to cut values out of an array does not change the next index of an existing iterator.

var a = [1, 2, 3, 4, 5, 6, 7, 8];
var s = '';
for (var v of a) {
    s += v;
    a.shift();
}
assertEq(s, '1357');