Currently ControllerResolver is responsible for determining the parameters to pass to controller actions. It does so via Reflection matching request attribute names to action parameter names. For parameters using the Request type hint it however knows to inject the Request instance.

Now in FOSRestBundle we have a need to inject parameters by type hint. Which leads to having to do the same work again. See for example:
FriendsOfSymfony/FOSRestBundle#745

So it might make sense to provide some way to tell the ControllerResolver for whatever other type hints to look for and what attributes to map them to.