3v4l.org

run code in 300+ PHP versions simultaneously
<?php const FOO = []; var_dump(isset(FOO['bar']));;
Output for 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 - 8.2.18, 8.3.0 - 8.3.6
bool(false)
Output for 5.6.0 - 5.6.40
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in /in/avG7B on line 1
Process exited with code 255.

preferences:
231.81 ms | 401 KiB | 291 Q