isset, empty, unset, exit, die, clone, eval
-----
<?php

isset($a, $a[$b]);
empty($a);
empty('foo');
unset($a, $a[$b]);
exit;
exit();
exit(1);
die;
die();
die('foo');
clone $foo;
eval('str');
-----
isset($a, $a[$b]);
empty($a);
empty('foo');
unset($a, $a[$b]);
exit;
exit;
exit(1);
die;
die;
die('foo');
clone $foo;
eval('str');