I've never implemented a lint before, but would like to try implementing this one if it's deemed useful:)

The same goes for wrapping in &PathBuf::from, which is even since it makes a completely needless allocation

Reading through the guide, it looks like this lint will need to be late-pass, and so somewhat more complicated. The guide mentions LatePassLint, but it's hard to understand what its methods are supposed to do since there doesn't seem to be any documentation whatsoever. I would appreciate pointers to similar lints so that I could hopefully imitate them...

A lint pass visits the whole crate, whenever the visitor sees an expression for example it calls check_expr, when it sees an item it will call check_item etc.

The individual docs for Item, Expr and so on have more details