Static cast template

[Rene Zwanenburg]

A part of the project I'm currently working on relies heavily on 
messages being sent between objects. There's some sort of 
container object which receives the messages, and notifies any 
listeners registered to it. We can't send the messages to the 
final recipients directly because the sender doesn't know about 
the receivers existence and vice versa.

There are many types of messages, but they all implement a 
Message interface. The messageListeners cast the Message to some 
ConcreteMessage, but the casting is starting to take a 
significant percentage of execution time. Due to the way 
MessageListeners are registered, we can be sure a MessageListener 
only receives the type of messages it's interested in, so the 
cast will never fail.

I'm looking for a static_cast construct, which will be checked 
during debug, but in release mode it should minimize overhead by 
simply adding the interface offset to the pointer. I've tried to 
make use off Type.classinfo's interfaces member, but for some 
reason a Type's classinfo isn't available at compile time.

So my question comes down to: does anyone know of a way to get 
static_cast behavior for upcasts?