Online PHP editor | output for 5nStL

<?php class Test extends stdClass implements ArrayAccess { private $container = []; public function offsetExists($key): bool { return isset($this->container[$key]); } public function offsetGet(mixed $key): mixed { return $this->container[$key]; } public function offsetSet($key, $value): void { $this->container[$key] = $value; } public function offsetUnset($key): void { unset($this->container[$key]); } } $test = new Test(); function foo(stdClass $c) { var_dump(isset($c[0])); } foo($test);