I’m kinda confused by this discussion. In the Forms sample code mentioned by the OP, why can we not simply use Msg? We’re in a very simple “app” at this point and there is only one message type so far. We haven’t introduced type variables, and these functions are locally scoped, so what is the purpose of having a type variable there when the reader is unlikely to understand it?
Once type variables are introduced, we can introduce msg as a common type variable for messages, and then things make sense going forward.