ref: bc9ee15fdd4a4c961bac0de2f4f9c4fceccd4a86
dir: /test/nestucon.myr/
use std
type t = struct
x : union
`Int int
`Str byte[:]
;;
;;
const main = {
var a : t
a = [.x = `Str "asdf"]
match a
| [.x=`Str s]: std.put("{}\n", s)
| _: std.die("Impossible match failure\n")
;;
}