David Allsopp wrote:
> ** Furthermore, I can't even hide these redundant types in the
> implementation:
>
> Foo.mli
>
> type t = [ `A | `B ]
>
> Foo.ml
>
> type t' = [ `A ]
> type t = [ `A | t' ]
>
> Is not valid even though t is /effectively/ the same p-variant in both the
> .mli and .ml
>   
That's maybe just because of a typo (you wrote `A for `B below) ?

This seems to works with 3.09:

# module M : sig type t = [ `A | `B ] end = struct type t' = [`A] type t 
= [`B | t' ] end;;
module M : sig type t = [ `A | `B ] end

Frédéric