3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array(1,2,3); foreach ($a as &$b) { } foreach ($a as $b) { var_dump($b); }
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
int(1) int(2) int(2)

preferences:
172.28 ms | 404 KiB | 235 Q