3v4l.org

run code in 300+ PHP versions simultaneously
<?php function &test() { $var = array(); $var[] =& $var; return $var; }; $a = test(); $b = $a; $b[0] = 123; print_r($a); print_r($b);
Output for 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
Array ( [0] => 123 ) Array ( [0] => 123 )
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38
Array ( [0] => Array *RECURSION* ) Array ( [0] => 123 )
preferences:
152.6 ms | 408 KiB | 5 Q