ref: 11ff08b7c5d3d682628b27e0a37b9d7e4deb28b7 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 }