REASONML Two modules

rec.ml

module Sig =
  struct
    module type NoteSig  = sig type t end
    module type TodoSig  = sig type t end
  end
module Same =
  struct
    module rec Note:Sig.NoteSig = struct type t = {
                                           todo: Todo.t;} end
    and Todo:Sig.TodoSig = struct type t = {
                                    notes: Note.t array;} end
  end
module A =
  struct module Note(T:Sig.TodoSig) = struct type t = {
                                               todo: T.t;} end end
module B =
  struct
    module Todo(N:Sig.NoteSig) = struct type t = {
                                          notes: N.t array;} end
  end
module C =
  struct
    module rec NoteImpl:Sig.NoteSig = A.Note(TodoImpl)
    and TodoImpl:Sig.TodoSig = B.Todo(NoteImpl)
  end
let todo1: Same.Todo.t = { notes = [||] }
let todo2: C.TodoImpl.t = { notes = [||] }

Here is the error

  33 │
  34 │ /* impl */
  35 │ let todo1: Same.Todo.t = {notes: [||]};
  36 │ let todo2: C.TodoImpl.t = {notes: [||]};
  37 │ Js.log2(todo1, todo2);

  The record field notes can't be found.

  If it's defined in another module or file, bring it into scope by:
  - Annotating it with said module name: let baby = {MyModule.age: 3}
  - Or specifying its type: let baby: MyModule.person = {age: 3}