src/third_party/mozjs-45/js/src/jit-test/tests/basic/testStringResolve.js

function testStringResolve() {
    var x = 0;
    for each (let d in [new String('q'), new String('q'), new String('q')]) {
        if (("" + (0 in d)) === "true")
            x++;
    }
    return x;
}
assertEq(testStringResolve(), 3);