Description:
------------
Using $this as parameter is possible, but when using it (except from printing it out) $this referes to itself

It is also possible to change $this via reference.
The object name seems to get changed - but when using it it works fine.

Reproduce code:
---------------
<?php
class foo {
        function __construct($this) {
                printf("ctor \$this parameter is: %s\n", var_export($this, 1));
                self::overwrite($this);

                printf("Returning from self::overwrite \$this is: %s", get_class($this));
                $this->hello();
        }
        function overwrite(&$obj) {
                $obj = new stdclass;
                printf("self::overwrite \$this is: %s\n", get_class($this));
        }
        function hello() {
                printf(" ...lier! \$this is still %s\n", get_class($this));
        }
}
$obj = new foo("Hello world");
var_dump($obj);



Actual result:
--------------
ctor $this parameter is: 'Hello world'
self::overwrite $this is: foo
Returning from self::overwrite $this is: stdClass ...lier! $this is still foo
object(foo)#1 (0) {
}