Description:
------------
take a look at the following script

<?php
class B {
    public $b = 50;

    public function whoami () {
        var_dump (__CLASS__);
    }
}

class A {
    public $a = 6;

    function thisref () {
        var_dump ($this); // A
        $this->ref ($this); // exchange $this by a B object
        var_dump ($this); // B
        var_dump ($this->a); // 6
        var_dump ($this->b); // Notice: Undefined property: A::$b
        var_dump (isset ($this->a)); // true
        var_dump (property_exists ($this, "a")); // false
        var_dump (__CLASS__); // A
        $this->whoami (); // A
        var_dump ($this instanceof self ? "A" : "B"); // B
    }

    function ref (A &$ref) {
        $ref = new B();
    }

    public function whoami () {
        var_dump (__CLASS__);
    }
}

$a = new A();
$a->thisref ();
?>

it supplies $this variable as a property to a byref function, then changing it to a diffrent type.

if gives some strange results

Expected result:
----------------
it should not be possible to supply $this as a byref param

Actual result:
--------------
$this seems to be changed, however any call upon $this seems not, so properties and methods remain unchanged.