Online PHP editor | refs for DXVnX

<?php class Foo { public $x; } function id_from_prop(object $obj, string $prop) { $id = (ReflectionReference::fromArrayElement((array) $obj, $prop))?->getId(); return $id ? bin2hex($id) : null; } $foo = new Foo(); $x = 42; $foo->x = &$x; var_dump(id_from_prop($foo, 'x')); var_dump(id_from_prop($foo, 'x')); $y = &$z; var_dump(id_from_prop($foo, 'x'));