Description:
------------
When i extend SimpleXMLElement there is some weird issue on accessing variable of the class. (perhaps related to bug #28817, i'm not completely sure)

Reproduce code:
---------------
<?php
class Reader extends SimpleXMLElement {
	public $test;
	public function extract()
	{
		$this->test=array();
		var_dump(is_array($this->test));
	}
}
$uploadfile="file.xml";
$rs=simplexml_load_file($uploadfile,"Reader");
$rs->extract();

?>

Expected result:
----------------
bool(true)

Actual result:
--------------
bool(false)