Description:
------------
I looks like you have never do in-depth testing with ArrayAccess. I you did you must realize many things are wrong there. It took me less then 5 minutes to kill PHP several times using this naively implemented feature.




Reproduce code:
---------------
class ArrayClass implements ArrayAccess {

public $a = array();

function offsetExists($index) {

    return array_key_exists($index, $this->a);

}

function offsetGet($index) {

    return $this->a[$index];

}

function offsetSet($index, $newval) {

    return $this->a[$index] = $newval;

}

function offsetUnset($index) {

    unset($this->a[$index]);

}

}



Expected result:
----------------
It's unclear for me what should I expect.
Definitly not the crashes.

Can anyone explain, what should I expect from e.g.
$obj[1][2][3] = 1; ?

And what should 
$a =& $obj[1][2][3];
do?


Actual result:
--------------
$obj[array()] = 1; // crash
$obj[][] = 1;      // crash
$x =& $obj[1]      // crash
$obj[$obj[1]] = 1; // if offsetGet() returns null, the offsetSet() is called then
$obj[1]++; // doesn't work at all even if both offsetGet and offsetSet are modified to return by reference