Is it possible to give type constraints involving variant types?
If there is e.g.

module type A = sig
 type t = A of 'a | B of 'b
end

module type B = sig
 module A : A
end

Can I then do something like

module type C = sig
 module B : B
 module A : A
  with type t = B.A.t = A of 'a | B of 'b
end

The above yields a syntax error, but there should be a way of doing
that or not?

cheers

christian