3v4l.org

run code in 300+ PHP versions simultaneously
<?php trait Eq { abstract public function equiv(Eq $lhs, Eq $rhs): bool; } class Number { use Eq; public function __construct(public int $value) {} public function equiv(int $lhs, int $rhs): bool { return $lhs === $rhs; } }
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Declaration of Number::equiv(int $lhs, int $rhs): bool must be compatible with Eq::equiv(Eq $lhs, Eq $rhs): bool in /in/2T5dP on line 11
Process exited with code 255.

preferences:
125.94 ms | 402 KiB | 89 Q