3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array(a => 'a', b => 'b' ); $b = array(a => 'a_p', b => 'b_p' ); $c = array_merge($a, $b); var_dump($c);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Uncaught Error: Undefined constant "a" in /in/I06J2:3 Stack trace: #0 {main} thrown in /in/I06J2 on line 3
Process exited with code 255.
Output for 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33
Warning: Use of undefined constant a - assumed 'a' (this will throw an Error in a future version of PHP) in /in/I06J2 on line 3 Warning: Use of undefined constant b - assumed 'b' (this will throw an Error in a future version of PHP) in /in/I06J2 on line 3 Warning: Use of undefined constant a - assumed 'a' (this will throw an Error in a future version of PHP) in /in/I06J2 on line 4 Warning: Use of undefined constant b - assumed 'b' (this will throw an Error in a future version of PHP) in /in/I06J2 on line 4 array(2) { ["a"]=> string(3) "a_p" ["b"]=> string(3) "b_p" }
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 - 5.5.37, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20
Notice: Use of undefined constant a - assumed 'a' in /in/I06J2 on line 3 Notice: Use of undefined constant b - assumed 'b' in /in/I06J2 on line 3 Notice: Use of undefined constant a - assumed 'a' in /in/I06J2 on line 4 Notice: Use of undefined constant b - assumed 'b' in /in/I06J2 on line 4 array(2) { ["a"]=> string(3) "a_p" ["b"]=> string(3) "b_p" }
preferences:
256.23 ms | 404 KiB | 351 Q