I believe that implicit in this scheme is that you cannot remove dependencies. It seems possible to add new dependencies, however. Changing dependencies can be

I believe that implicit in this scheme is that you cannot remove dependencies. It seems possible to add new dependencies, however. Changing dependencies can be seen as removing one and adding the other, but you can only do one, not the other. This limitation could probably be patched up by resolving a set of versions and then noticing that X1.1 is unreachable and discarding it. The trouble with that fix would be if X1.1 forces some other package to an unnecessarily high version even though it ends up being discarded.