3v4l.org

run code in 500+ PHP versions simultaneously
<?php interface A { public function __invoke(string $a); } interface B { public function __invoke(string $a); } class C implements A , B { public function __invoke(string|int $a) { } }
Output for 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3

preferences:
51.86 ms | 696 KiB | 4 Q