3v4l.org

run code in 500+ PHP versions simultaneously
<?php $a = [1, 2]; $a[] = &$b; $b = 4; print_r($a);
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.31, 8.3.0 - 8.3.31, 8.4.1 - 8.4.22, 8.5.0 - 8.5.8
Array ( [0] => 1 [1] => 2 [2] => 4 )
preferences:
74.35 ms | 1134 KiB | 4 Q