Online PHP editor | output for OUAgd

<?php declare(strict_types = 1); abstract class SomeAbstractClass { private bool $someValue = true; /** * @phpstan-assert-if-true static $other */ public function equals(?self $other): bool { return $other instanceof static && $this->someValue === $other->someValue; } } class SomeConcreteClass extends SomeAbstractClass { public function __construct( private bool $someOtherValue, ) {} public function equals(?SomeAbstractClass $other): bool { return parent::equals($other) && $this->someOtherValue === $other->someOtherValue; } } $a = new SomeConcreteClass(true); $b = new SomeConcreteClass(false); var_dump($a->equals($b), $b->equals($b));