fcm_are_cool.ml

module type S1 = sig
  val row_a : int
  val row_b : float
end
module type S2 = sig
  val row_b : float
  val row_a : int
end
module type V = sig
  val row_a : int
end
let f_poly ((module V: V)) =
  Printf.printf "row_a: %d\n%!" V.row_a
let s1 = (module struct
  let row_a = 1
  let row_b = 1.0
end: S1)
let s2 = (module (val s1) : S2)
let () = f_poly (module (val s1))
let () = f_poly (module (val s2))