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run code in 150+ php & hhvm versions
Bugs & Features
<?php $vars = get_defined_vars(); $mystring = null; $vars = @array_diff(get_defined_vars(),$vars); var_dump($vars);
Output for 4.3.0 - 5.6.21, 7.0.0 - 7.1.0
array(1) { ["mystring"]=> NULL }
Output for hhvm-3.10.0 - 3.12.0
array(0) { }