Description:
------------
well,

when i try to use unserialize in a class on the object itself,
that's return me an empty object, all property are set to NULL.

the code below work well with php4, but doesn't with php5.

Reproduce code:
---------------
<?php
class a {
    var $x;  
    function unS($serial) {
        $this = unserialize($serial);
    }
}

$test1 = new a;
$test1 -> x = 'blabla';
var_dump($test1);

$serial = serialize ($test1);
var_dump($serial);

$test2 = new a;
$test2->unS($serial);
//$test2 = unserialize($serial);
var_dump($test2);
?>

Expected result:
----------------
i expected the same behaviour as in php4. php5 return me the right result when i use unserialize out of the class but return me an empty object when i use it in the class.

actual result
-------------------------
object(a)#2 (1) {
  ["x"]=>
  NULL
}


expected result
-------------------------
object(a)#2 (1) {
  ["x"]=>
  string(7) "blabla"
}