Description:
------------
$this can be changed when you use an automagic function.

Reproduce code:
---------------
<?php
function change(&$var, $value) {
	$var = $value;
	return true;
}
class foo {
	function __construct() {
		change($this, false);
		var_dump($this);
	}
}
$foo = new foo;
?>


Expected result:
----------------
HTTP/1.1 500 Internal Server Error

Fatal error: Cannot re-assign $this in %s on line %d


Actual result:
--------------
HTTP/1.1 200 OK

bool(false)