@loostro ,

Yes, have a look at ``isGranted`` declaration function http://api.symfony.com/2.0/Symfony/Component/Security/Core/SecurityContext.html#method_isGranted

default value for second parameter is ``null``
so calling ``isGranted(new Expression('{{ credentials }}'), null)`` is equivalent to ``isGranted(new Expression('{{ credentials }}'))``
Take care that ``null`` is not in the ``Expression`` but in the ``isGranted`` call