> the uutils authors are well experienced in Rust

I'm not sure that they were all that experienced in Rust when most of this code was written. uutils has been a bit of a "good first rust issue" playground for a lot of its existence

Which makes it pretty unsurprising that the authors also weren't all that well versed in the details of low-level POSIX API

It's not designed to completely eliminate other bug classes but it is designed to reduce the chance that they happen.

In this case the filesystem API was perhaps not as well designed as it could have been. That can potentially be fixed though.

Some of the other bugs would be hard to statically prevent though. But nobody ever claimed otherwise.