3v4l.org

run code in 300+ PHP versions simultaneously
<?php final class DemoFile { private ?callable $prop = null; public function set(callable $prop): void { $this->prop = $prop; } private function reset(): void { $this->prop = null; } }
Output for 8.1.0 - 8.1.29, 8.2.0 - 8.2.23, 8.3.0 - 8.3.11
Fatal error: Property DemoFile::$prop cannot have type ?callable in /in/bGlmf on line 5
Process exited with code 255.

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