Hi,

> I'm using the structural subtyping aspects of Ocaml's object system to emulate width
> subtyping.  I've come across a problem which does not type-check, though intuitively
> it seems correct.  I reckon that the compiler may need some help in the form of type
> annotations and/or coercions, though their exact shape elludes me.

Thank you all for your assistance.  In the real-world code, the solution
based on coercion is the most straightforward to implement.  And it looks
obvious now...

Cheers,
Dario Teixeira