Mypal/js/src/jit-test/tests/basic/testBug566556.js

var msg = "";
try {
    this.__defineSetter__('x', Object.create);
    this.watch('x', function() {});
    x = 3;
} catch (e) {
    msg = e.toString();
}
assertEq(msg, "TypeError: undefined is not an object or null");