Description:
------------
after a referance assignment, the result of the expression will be an un expected value.

Reproduce code:
---------------
<?php
$a = 1;
$c = ++$a+$a++;
echo $c; 
echo "\n";
$a = 1;
$b = &$a;
$c = ++$a+$a++;
echo $c; 
?>

Expected result:
----------------
4
4

Actual result:
--------------
4
5