ref: 9a83081ebe28cc5d5e52718f3d0ef2d0a6df21b7 dir: /libstd/swap.myr/
pkg std = generic swap : (a : @a#, b : @a# -> void) ;; generic swap = {a : @a#, b : @a# var t t = a# a# = b# b# = t }