ref: 0f95e4517ef3aa5d719b0ba8a20e8c64e96b0c46 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 }