regression in example on homepage

[Andrew Chambers <andrewchamberss@xxxxxxxxx>]

Running the examples on the homepage, one has stopped working. Here is the
minimized failure. It prints  'pattern matched by earlier case' referring
to the .a patterns.


use std

type s = struct
        a : int
        b : (int, int)
;;

const main = {
        var v : s
        v = [.a = 123, .b=(5, 10)]
        match v
        | [.a = 234]:              std.put("Should not be here\n")
        | [.a = 123, .b=(x, y)]:   std.put("tuple is ({}, {})\n", x, y)
        | _:                       std.put("No matches: Generic case\n")
        ;;
}