Jeremy Yallop wrote:

>
> Unless I'm mistaken you can write this as
>
>     match x with
>     | Y (y as z)
>     | X (y,z)    -> f y z
>
> Is there some more general case for which this won't work out?
>

I often times want to be able to write code like:
    match foo with
    | Y (y) with x = 3
    | X(x, y) ->
       f x y

Brian