ref: f6f5d7086bc67d1c68d83d6f9bad1ea037e5e6c0 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 }