> But if it is yet to be defined (which is the case with mutually
> recursive definitions), you must keep everything monomorphic so that
> constraints can be enforced later.

OK, so I understand the following error message:

  # type 'a t = 'a and u = int t and v = bool t;;
  This type bool should be an instance of type int

But then, why is the following declaration accepted?

  # type 'a t = 'a and u = A of int t and v = B of bool t;;
  type 'a t = 'a
  type u = | A of int t
  type v = | B of bool t

I am still confused...

-- 
François Pottier
Francois.Pottier@inria.fr
http://pauillac.inria.fr/~fpottier/