Description:
------------
when extending class there is no access to parent::error, parent::errno

access to functions (query, set_charset, ...)works

Reproduce code:
---------------
class dbMYSQL extends mysqli {
...
function __construct(
parent::__construct($args....);
echo parent::errno;
echo parent::error;
}
...
}

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

or some error and error message when error occurs

Actual result:
--------------
Fatal error: Undefined class constant 'errno'
Fatal error: Undefined class constant 'error'