3v4l.org

run code in 300+ PHP versions simultaneously
<?php class x { public function m() {} } class y extends x { public function m():?string {} }
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4

preferences:
103.53 ms | 402 KiB | 85 Q