3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = []; $array["a"] =& $array["b"]; $array["b"] = 1; var_dump($array);
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.32, 8.2.0 - 8.2.28, 8.3.0 - 8.3.20, 8.4.1 - 8.4.6
array(2) { ["b"]=> &int(1) ["a"]=> &int(1) }
Output for 7.0.0 - 7.0.33
array(2) { ["a"]=> &int(1) ["b"]=> &int(1) }
preferences:
167.56 ms | 407 KiB | 5 Q