3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = []; $b = [['a'=>'foo'],['a'=>'bar']]; array_push(null, $b); var_dump($a);
Output for 5.4.0 - 5.4.39, 5.6.7
Fatal error: Only variables can be passed by reference in /in/n6kdd on line 5
Process exited with code 255.
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29
Parse error: syntax error, unexpected '[' in /in/n6kdd on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected '[' in /in/n6kdd on line 3
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/n6kdd on line 3
Process exited with code 255.

preferences:
120.63 ms | 401 KiB | 128 Q