Description:
------------
Whenever I create a class which inherits DOMElement, and I create an instance of this class, the type of the class is "forgotten" when the variable holding the instance goes out of scope, even though the actual instance should still exist as it is part of the DOM tree. So, what you get is that the inherited DOMElement still exists in the DOM tree, but the subclass instance is gone.



Reproduce code:
---------------
<?php

class Widget extends DOMElement {
	public function __construct() {
		parent::__construct('p');
	}

	public function say() {
		echo "I am a widget!\n";
	}
}

$doc = new DOMDocument();
$doc->appendChild($html = new DOMElement('html'));
$html->appendChild($body = new DOMElement('body'));
$body->appendChild(new Widget());
$body->firstChild->say();

?>

Expected result:
----------------
It should say: "I am a widget!".

You can get this expected result by changing the line:
  $body->appendChild(new Widget());
to:
  $body->appendChild($widget = new Widget());

this way, the widget will not get out of scope and the actual class is remembered.

Actual result:
--------------
You will get an error saying: "Fatal error: Call to undefined method DOMElement::say() in testcase.php on line 17"