Or I guess what you're saying is that uutils is a cross platform project? Which is true enough, but it's still responsible for faithfully representing the behavior of the underlying system. And when running uutils on linux, stating "." (in this case to detect that src and dst are the same file) is legal and valid.
It's true there are other ways to solve the same problem than emulating a linux syscall layer, but you have to pick one. You don't get to use "the standard library can't stat ." or "we have to run on windows" as an excuse.
[1] And I'll admit that I don't have any understanding of the actual low level issue here or why native pathnames are being interpreted by the runtime and not passed through to the OS layer.
[1] Maybe this is all just a semantic argument about this use of the word "broken"? This is a long-standing usage. It doesn't mean that Rust's standard library isn't useful for anything, it means that it isn't useful here because of design choices that don't match the problem at hand. If it were something that can be fixed, it would just be "buggy". But it can't (for the reasons you mention!). Therefore it's "broken", not "buggy".
This isn't a Linux project, it is a cross-platform project.