3v4l.org

run code in 300+ PHP versions simultaneously
<?php $o=(object)array();$o->o = $o;print_r($o);
Output for 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 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
stdClass Object ( [o] => stdClass Object *RECURSION* )
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9
stdClass Object ( [o] => stdClass Object ( ) )

preferences:
157.56 ms | 402 KiB | 342 Q