3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = array('a1' => x);
based on LH6YX
Output for 7.2.0
Warning: Use of undefined constant x - assumed 'x' (this will throw an Error in a future version of PHP) in /in/6YsLb on line 3
Output for 5.3.21 - 7.1.10
Notice: Use of undefined constant x - assumed 'x' in /in/6YsLb on line 3