Description:
------------
After using foreach($arr as $k => &$v) to modify the $arr, 
iterating again using the same variable $v causes the array to 
be altered unexpectedly.

Adding an unset($v) between the two foreach loops, or using a 
different variable on the second foreach loop works around the 
problem.

Reproduce code:
---------------
<?

$arr = array(
	'one' => 1,
	'two' => 2,
	'three' => 3,
);

foreach($arr as $k => &$v)
	if($v == 1)
		$v = 'meh';

print_r($arr);

foreach($arr as $k => $v)
	;

print_r($arr);


Expected result:
----------------
The code above should not cause the $arr to be modified by 
running the second foreach loop.

Actual result:
--------------
The code above outputs the following:

Array ( [one] => meh [two] => 2 [three] => 3 )
Array ( [one] => meh [two] => 2 [three] => 2 )