I hope I'll not spam the list, but I wanted to show off a simple example of the type checking done for guile. It follows typed racked features. What's missing is the possibility to typecheck e.g. map with arbitrary many arguments. But recursive types are in and seems to work.
What needs to go in is a better handling of lambdas, and the possibility to declare functions with arbitrary many arguments like in typed racket. Keyword arguments needs to work as well.