3v4l.org

run code in 500+ PHP versions simultaneously
<?php $a=[1]; $a[]=&$a; print_r($a);
Output for 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 - 8.1.34, 8.2.0 - 8.2.31, 8.3.0 - 8.3.31, 8.4.1 - 8.4.22, 8.5.0 - 8.5.7
Array ( [0] => 1 [1] => Array *RECURSION* )
preferences:
81.07 ms | 1512 KiB | 4 Q