3v4l.org

run code in 300+ PHP versions simultaneously
<?php trait Foo { public abstract function foo(mixed $value): void; } class A { use Foo; public function foo($value): void { echo $value; } } (new A)->foo('ok');
Output for 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
ok

preferences:
58.64 ms | 406 KiB | 5 Q