I don't see it as a problem yet, `mod` still means submodule, and `crate` still means top level. The fact one is defining a new grouping structure and the other

I don't see it as a problem yet, `mod` still means submodule, and `crate` still means top level. The fact one is defining a new grouping structure and the other is defining visibility is slightly unfortunate, but probably not a huge deal.