1--TEST--
2Make sure optimization does not interfere with yield by ref
3--FILE--
4<?php
5
6function &gen() {
7    yield $v = 0;
8    yield $v = 1;
9}
10
11foreach (gen() as $v) {
12    var_dump($v);
13}
14
15?>
16--EXPECTF--
17Notice: Only variable references should be yielded by reference in %s on line %d
18int(0)
19
20Notice: Only variable references should be yielded by reference in %s on line %d
21int(1)
22