Description:
------------
When setting value to an object returned from an overloaded array produces bogus "Indirect modification of overloaded element of foo has no effect" warning

Reproduce code:
---------------
<?php
class foo implements ArrayAccess {
        private $array;
        public function offsetSet($key, $value) {
                $this->array[$key] = $value;
        }
        public function offsetGet($key) {
                return $this->array[$key];
        }
        public function offsetExists($key) {}
        public function offsetUnset($key) {}
}
$foo = new foo;
$std = new stdclass;

$foo["bar"] = array($std);
$foo["bar"][0]->std = "foo";
var_dump($foo);



Actual result:
--------------
Notice: Indirect modification of overloaded element of foo has no effect in /usr/home/bjori/test/bogus.warning.php on line 17
object(foo)#1 (1) {
  ["array:private"]=>
  array(1) {
    ["bar"]=>
    array(1) {
      [0]=>
      object(stdClass)#2 (1) {
        ["std"]=>
        string(3) "foo"
      }
    }
  }
}