3v4l.org

run code in 300+ PHP versions simultaneously
<?php class B { public readonly int $x; public function getX(): int { return $this->x; } } class C extends B { // Redeclare to make it writable. public readonly int $x; public function __construct() { $this->x = 5; } } $c = new C; print $c->getX();
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
5

preferences:
56.15 ms | 406 KiB | 5 Q