Description:
------------
It's possible to change value of static protected member with a tricky code like the one below (pay attention to the "()" around the method call).

Reproduce code:
---------------
class ObjectPath
{
    static protected $type = array(0=>'main');

    static function getType()
    {
        return self::$type;
    }
}
var_dump(ObjectPath::getType());
$object_type = array_pop((ObjectPath::getType()));
var_dump(ObjectPath::getType());


Expected result:
----------------
array(1) {
  [0]=>
  string(4) "main"
}
array(1) {
  [0]=>
  string(4) "main"
}

Actual result:
--------------
array(1) {
  [0]=>
  string(4) "main"
}
array(0) {
}