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

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