[Caml-list] Implicit question about searching for implicit module definition in the functor argument.

[Kakadu <kakadu.hafanana@gmail.com>]

Hey, hackers.

I'm missing something obvious. Any fresh eyes around?

module type SHOW = sig
    type t
    val show : t -> string
end

let show {S : SHOW} x = S.show x;;

implicit module Show_int : (SHOW with type t = int) = struct
    type t = int
    let show = string_of_int
end

module type CORE = sig
  type 'a logic

  implicit module Show_logic(X: SHOW) : (SHOW with type t = X.t logic)
end

module Make(MK: CORE) = struct
  open MK
  open implicit MK (* doesn't help *)

  let foo (x: int logic) =
    let s = show x in (* Error: No instance found for implicit S. *)
    s
end


Kind regards,
Kakadu