ref: e65d5c4019e76430398e4ebc1cb734f1efea3b14
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")
;;
}