Oooh, here we go! As a professional Elixir developer for... 10-ish years now, I've been super excited about types coming. I'm very excited that the beginnings have started to land here.

That said, I would love to know how the state of what's in v1.20 compares to un-spec'ed dialyzer. I was under the impression that dyalizer's "success typing" approach (not flagging a function if there are some combination of parameters such that it works, rather than flagging it if some combination of parameters can make it fail) was like what Elixir is doing here, and I haven't found dialyzer terribly useful.