3v4l.org

run code in 300+ PHP versions simultaneously
<?php ini_set('display_errors', 1); ini_set('display_startup_errors', 1); error_reporting(-1); $x = 12; $y = &$x; $ar = ['a' => 1, 'b' => 2]; $z = &$ar['b']; var_dump($ar);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 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 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
array(2) { ["a"]=> int(1) ["b"]=> &int(2) }
preferences:
208.93 ms | 404 KiB | 293 Q