add size_list_to_map
There's probably a way to do this without assuming that the map has some associated domain... but this was the easiest proof, and in practice the map types we work with do have a domain, so it should be fine.
There's probably a way to do this without assuming that the map has some associated domain... but this was the easiest proof, and in practice the map types we work with do have a domain, so it should be fine.