3v4l.org

run code in 300+ PHP versions simultaneously
<?php class a { protected $a = 10; protected $c;} class b { protected $b; public function setA($a){$this->b = $a;return $this;}} echo serialize((new b)->setA(new a));
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
O:1:"b":1:{s:4:"*b";O:1:"a":2:{s:4:"*a";i:10;s:4:"*c";N;}}

preferences:
218.35 ms | 404 KiB | 330 Q