File "pr10693_bad.ml", line 27, characters 26-27:
27 | module Bad (A : S') : S = A
                               ^
Error: Signature mismatch:
       Modules do not match:
         sig val x : 'a option module M : Dep -> S end
       is not included in
         S
       In module M:
       Modules do not match:
         Dep -> S
       is not included in
         (X : Dep) ->
           sig
             val x : X.t option
             module M : (Y : Dep) -> sig val x : X.t option end
           end
       In module M:
       Modules do not match:
         S
       is not included in
         sig
           val x : X.t option
           module M : (Y : Dep) -> sig val x : X.t option end
         end
       In module M.M:
       Modules do not match:
         (X : Dep) ->
           sig
             val x : X.t option
             module M : (Y : Dep) -> sig val x : X.t option end
           end
       is not included in
         (Y : Dep) -> sig val x : X.t option end
       In module M.M:
       Modules do not match:
         sig
           val x : X.t option
           module M : (Y : Dep) -> sig val x : X.t option end
         end
       is not included in
         sig val x : X.t option end
       In module M.M:
       Values do not match:
         val x : X.t option
       is not included in
         val x : X/2.t option
       The type X.t option is not compatible with the type X/2.t option
       Type X.t is not compatible with type X/2.t
       File "_none_", line 1:
         Definition of module X
       File "_none_", line 1:
         Definition of module X/2
       File "pr10693_bad.ml", line 17, characters 6-24: Expected declaration
       File "pr10693_bad.ml", line 15, characters 4-22: Actual declaration