Description:
------------
There is some incostistency with foreach and a class which has __get and __set methods. I don't know what is the intended behaviour but there is a problem there when assigning a foreach key or value to an overloaded member of such class.

See comments in the expected result region.

Reproduce code:
---------------
<? class abc {
	function __set ($key, $value) { echo "__set ($key,$value)<br/>"; $this->arr[$key] = $value; }
	function /*&*/ __get ($key) { echo "__get ($key)<br/>"; return $this->arr[$key]; } 
	function __isset ($key) { echo "__isset ($key)<br/>"; return isset ($this->arr[$key]); }
	function __unset ($key) { echo "__unset ($key)<br/>"; unset ($this->arr[$key]); }
	private $arr;
}
$abc = new abc();
foreach (array (1,2,3) as $abc->k => $v) {
	print_r($abc);echo ';'; var_dump($abc->k);echo ';';
}
$abc->k = 4;
echo '-----<br/>';
foreach (array (1,2,3) as $abc->k => $v) {
	print_r($abc);echo ';'; var_dump($abc->k);echo ';';
}
echo '<br/>-----<br/>';
$abc_value = new abc();
foreach (array (1,2,3) as $v => $abc_value->k) {
	print_r($abc_value);echo ';'; var_dump($abc_value->k);echo ';';
}


Expected result:
----------------
Depends of specification.

Case 1 : First foreach fills $arr with keys. Others are ok.
Case 2 : Second foreach does not fill $arr with keys.

Note 1! 
When __get is changed to return by reference, first foreach behaves exactly like the second one.

Note 2!
Third foreach calls __set while first and second do not.

Actual result:
--------------
__get (k)
abc Object ( [arr:private] => Array ( ) ) ;__get (k)
NULL ;__get (k)
abc Object ( [arr:private] => Array ( ) ) ;__get (k)
NULL ;__set (k,4)
-----
__get (k)
abc Object ( [arr:private] => Array ( [k] => 0 ) ) ;__get (k)
int(0) ;__get (k)
abc Object ( [arr:private] => Array ( [k] => 1 ) ) ;__get (k)
int(1) ;
-----
__set (k,1)
abc Object ( [arr:private] => Array ( [k] => 1 ) ) ;__get (k)
int(1) ;__set (k,2)
abc Object ( [arr:private] => Array ( [k] => 2 ) ) ;__get (k)
int(2) ;