Description:
------------
Basically, when you try to assign anything to ArrayObject[null]['any_key'], it fails as it should, but since that moment anytime you access a non-existing key in any array, you get the last created zval, or so it seems.

Strangely enough, all warnings and notices are shown and isset() returns false.

Test script:
---------------
<?

	$a = new ArrayObject();
	
	$b = [];
	
	$a[null]['hurr'] = 'durr';
	
	var_dump($a['epic_magic']);
	var_dump($b['epic_magic']);
	var_dump($c['epic_magic']); // Undefined var!!
	
	$d = [];
	var_dump($a['epic_magic']); // more magic!
	var_dump($d['epic_magic']);
	
	$e = 'srsly?';
	var_dump($a['epic_magic']); // srsly.


Expected result:
----------------
Warning: Illegal offset type in /home/virtuall/epic.php on line 7
NULL
NULL
NULL
NULL
NULL
NULL
bool(false)


Actual result:
--------------
Warning: Illegal offset type in /home/virtuall/epic.php on line 7
array(1) {
  ["hurr"]=>
  string(4) "durr"
}
array(1) {
  ["hurr"]=>
  string(4) "durr"
}
array(1) {
  ["hurr"]=>
  string(4) "durr"
}
array(0) {
}
array(0) {
}
string(6) "srsly?"
bool(false)