Online PHP editor | refs for uFnp8

<?php #[Attribute()] final class Sealed { public array $permitted = []; public function __construct(string ...$permitted) { $this->permitted = $permitted; } } function validate(string $classname): void { $class = new ReflectionClass($classname); $validate_against = static function($parent) use($classname) { if ($sealed = $parent->getAttributes(Sealed::class)) { if (!in_array($classname, $sealed[0]->newInstance()->permitted, true)) { throw new Error($classname.' cannot inherit from sealed class '.$parent->getName()); } } }; if ($parent = $class->getParentClass()) { $validate_against($parent); } foreach($class->getInterfaces() as $interface) { $validate_against($interface); } foreach($class->getTraits() as $trait) { $validate_against($trait); } echo 'ok'; } #[Sealed(Bar::class)] interface Foo { } final class Bar implements Foo {} final class Baz implements Foo {} validate(Bar::class); validate(Baz::class);