I wonder if Rust would support something like the following. Say, I have a mmapped file, and in this file I'd like to store data-structures such as maps, sets, lists, etc. Basically, they are the same data-structures as one would use on the heap. Because the mmapped file is offsetted at a different point in memory every time it is opened, the actual pointers used to access these data-structures will be different every time. But the pointers <i>inside</i> the data-structures will be the same every time the file is mmapped. So, this requires some special pointer arithmetic (and perhaps a special type system). It would definitely be a very interesting and useful feature!