File "t05bad.ml", line 10, characters 0-75:
10 | module rec A : sig type t = B.t -> int end = struct type t = B.t -> int end
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error: The definition of A.t contains a cycle:
         B.t -> int contains B.t,
         B.t = A.t,
         A.t = B.t -> int,
         B.t -> int contains B.t,
         B.t = A.t