ref: 8de1cdde541f65ff1394f12fd57452cda63099ce
dir: /test/fmtalign.myr/
use std pkg = type msg = union `Tversion tversion ;; type tversion = struct tag : uint16 version : byte[:] ;; ;; const main = { var msg=`Tversion [.tag=45, .version="9P2000"] std.put("{}\n", msg) }