>
> Well, to ensure the coherence of the with constraints, we require that
> the new signature be a subtype of the original one (as a module, not as an
> object).
> This is where your code gets rejected.
>
> Now why is it deemed unsafe to allow a constrained type definition to be a
> subtype of
> an unconstrained one?
> Actually, I don't know.
> The unconstrained type does not enforce the invariants of the constrained
> one,
> but they will be checked as soon as you try to unify the two.
> So it may be possible to lift this restriction.
>

It sounds pretty unlikely. If I have a functor taking a T in argument and I
pass it a T with constraints, it's likely to be inconsistent.

May I wonder, though, about the reason why T with blah should be a subtype
of T? I must confess I fail to see the point.


Arnaud