Description:
------------
Using array access on $this in ArrayObject::offsetSet() causes a segmentation fault.

(Calling parent::offsetSet() instead, works fine)

Reproduce code:
---------------
class AOTest extends ArrayObject
{
	public function offsetSet($index, $newval)
	{
		$this[$index] = (int)$newval;
	}	
}

$a = new AOTest();
$a['test'] = "10 doves";
var_dump((array)$a);

Expected result:
----------------
array(1) {
  ["test"]=>
  int(10)
}


Actual result:
--------------
Segmentation fault