Description:
------------
The PHP-Parser doesn't recognise if a parameter with the same name is given over two times (no warning / error). In this case it was a copy-paste mistake, but it causes big troubles in our system.

Reproduce code:
---------------
class myCls extends otherCls {

     private function myFunc($var, $var) {
	//do something		
     }
}

Expected result:
----------------
A Warning should occur. Something like "Multible use of variable/parameter name in function myFunc".

Actual result:
--------------
Nothing. The second parameter replaces the value of the first.
If you don't give over an second parameter, the value of the first is nonsence or empty.