Is the following an expected change from OCaml 4.00.1 to 4.01.0?

Module Foo defines a private type and this module is included in Common. The signature within Common is defined using `module type of` with a constraint. The different behavior shown below occurs when the private type is a record, but not if it is a base type like string or int. In that case, the code compiles with both 4.00.1 and 4.01.0.

$ cat a.ml 

module Foo : sig

  type t = private {a:int}

end = struct

  type t = {a:int}

end

module Common : sig

  module F : module type of Foo with type t = Foo.t

end = struct

  module F = Foo

end

$ ocaml -version

The OCaml toplevel, version 4.01.0

$ ocaml a.ml

(* no errors *)

Now, change version of OCaml being used.

$ ocaml -version

The OCaml toplevel, version 4.00.1

$ ocaml a.ml

File "a.ml", line 9, characters 6-33:

Error: Signature mismatch:

       Modules do not match:

         sig module F : sig type t = Foo.t = private { a : int; } end end

       is not included in

         sig module F : sig type t = Foo.t = { a : int; } end end

       In module F:

       Modules do not match:

         sig type t = Foo.t = private { a : int; } end

       is not included in

         sig type t = Foo.t = { a : int; } end

       In module F:

       Type declarations do not match:

         type t = Foo.t = private { a : int; }

       is not included in

         type t = Foo.t = { a : int; }

       File "a.ml", line 8, characters 37-51: Expected declaration

       File "a.ml", line 2, characters 7-26: Actual declaration

       A private type would be revealed.