It would be to supplement Elixir. Any module you made in OCaml would output an Elixir module of the same name. You could call into it from normal Elixir code, and you could call normal Elixir code from the OCaml-output-version by the ‘external’ declaration, that is the easy stuff. Everything within a module you’d know would be typed-safe, so as long as the external Elixir modules call it right (and I could always add when checks and assertions and such at public points to verify) then no worry about something stupid within (like me passing a user object in the room field in one of my projects here…). Could slowly convert your code to OCaml or just add it as you go. The more you’d have, the safer the overall project would be.
OCaml itself does not have dependent types (few ML languages do, Haskell does not either), but you can emulate them via typed modules and probably GADT’s… Just playing with the idea of them in my playground here. 
