Author there. Let me explain - core.logic is a Prolog-like logic engine written in Clojure. It is in fact so similar to Prolog that it's actually quite trivial to port Prolog code as I've done here. The other nice bit is that core.logic is quite fast - it is not the toy implementation of Prolog that you see so often.
UPDATE: edited the examples to show concrete types so it's easier to understand.
With these two tools one can have a stronger type system than Haskell. PropEr is amazing work. Not to mention CED https://github.com/mariachris/CED which checks all possible state transitions for race conditions.
Yes, Dialyzer is quite cool. However it is run as a separate tool on your Erlang source right? What I'm aiming for is something that can be used interactively while at the REPL - Qi/Shen is the inspiration here.
UPDATE: edited the examples to show concrete types so it's easier to understand.