Description:
------------
indirect vars returned in properties for __sleep not handled correctly

Test script:
---------------
<?php
class foo
{
    private $private = 'private';
}

class bar extends foo
{
    public function __sleep()
    {
        return (new bar());
    }
}

var_dump(serialize(new bar()));
?>

Expected result:
----------------
Warning: serialize(): "private" returned as member variable from __sleep() but does not exist in /opt/src/php-src/sec.php on line 15
string(14) "O:3:"bar":0:{}"


Actual result:
--------------
assert fail