File "t08bad.ml", lines 10-11, characters 0-71:
10 | module rec A : sig type 'a t = <m: 'a list B.t; n: 'a array B.t> end
11 |              = struct type 'a t = <m: 'a list B.t; n: 'a array B.t> end
Error: This recursive type is not regular.
       The type constructor "A.t" is defined as
         type "'a A.t"
       but it is used as
         "'a array A.t"
       after the following expansion(s):
         "< m : 'a list B.t; n : 'a array B.t >" contains "'a array B.t",
         "'a array B.t" = "'a array A.t"
       All uses need to match the definition for the recursive type to be regular.