Description:
------------
When using protected __set() it still gets called from outside the class (parent or children) 

Reproduce code:
---------------
abstract class Example {
    private $data = array();
    protected function __set($key, $value) {
        $this->data[$key] = $value;
    }
    protected function __get($key) {
        return $this->data[$key];
    }
}

class MyExample extends Example {
    public function __construct($name, $value) {
        $this->$name = $value; // sets parent::$data[$name] = $key
    }
}
$c = new MyExample('name', 'foo');
echo $c->name; // echoes foo (Should not do so because Example::__get() is protected)
$c->name = 'bar'; // Should not be able to assign 'bar' Example::__set() protected, but does!
echo $c->name; // echoes bar (Should not do so because Example::__get() are protected)
var_dump($c);

Expected result:
----------------
I expected an error to be thrown saying that i am trying to access protected data and am not allowed to do so.

When setting a variable, from outside the class, i should be unable to do so error thrown! 

Actual result:
--------------
foo
bar
object(MyExample)#1 (1) 
{ 
    ["data:private"]=> array(1) 
    { 
        ["name"]=> string(3) "bar" 
    }
}