3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = null; var_dump(isset($a)); $a = ''; var_dump(isset($a)); $a = array(); var_dump(isset($a));
based on qOrUC
Output for 4.3.0 - 7.2.0
bool(false) bool(true) bool(true)