File "w32b.ml", line 13, characters 18-24:
13 | module Q (M : sig type t end) = struct end
                       ^^^^^^
Warning 34 [unused-type-declaration]: unused type t.

File "w32b.ml", line 13, characters 10-11:
13 | module Q (M : sig type t end) = struct end
               ^
Warning 60 [unused-module]: unused module M.