Description:
------------
I'm running into a problem when trying to extend a class that extends mysqli.  I cannot access any of the properties.  This is related to bug 28430 except here I am extending the class one level further.

Reproduce code:
---------------
<?php
error_reporting(E_ALL);

class a extends mysqli { }

class b extends a { }

$mysqli = new mysqli('localhost', 'username', 'password', 'db');
echo $mysqli->warning_count."\n";

$a = new a('localhost', 'username', 'password', 'db');
echo $a->warning_count."\n";

$b = new b('localhost', 'username', 'password', 'db');
echo $b->warning_count."\n";
?>


Expected result:
----------------
0
0
0


Actual result:
--------------
0
0

Notice: Undefined property:  b::$warning_count in /var/www/html/test.php on line 15