Zero-cost abstraction for NewTypes in Elixir

[03juan]

There was a discussion recently about changing the way dialyser matches on specs. Perhaps it might help you here?

Dialyzer cannot recognize error in function using polymorphic types

Background I am trying out polymorphic typing with dialyzer. As an example I am using the famous Option type (aka, Maybe Monad) that is now prevalent in many other languages these days. defmodule Test do @type option(t) :: some(t) | nothing @type some(t) :: [{:some, t}] @type nothing :: [] @spec validate_name(String.t()) :: option(String.t()) def validate_name(name) do if String.length(name) > 0 do [{:some, name}] else nil end end end As you can see, the f…