Seems like, one can't reexport a pub(super) items, this a annoying.

mod go {
    pub(super) use fpu_precision::set_precision;

    mod fpu_precision {
        pub(super) fn set_precision<T>() {} // should be `pub(crate)`
    }
}

I've completely reworked the logic to better use the effective visibility.

I've also locally tested the new logic on the core, alloc, panic_unwind and std crates with ./x.py fix and the new suggestions all successfully passed.

@rustbot ready

FWIW, I personally find the difference between pub(crate) and pub(super) to be of very little importance in practice, and I almost always use pub(crate). (In contrast, I find the difference between pub(crate|super) and pub is much more important, as is the difference between pub(crate|super) and no visibility.)

Is this change worth the extra complexity?

It's written in a very wordy way, but it's really just one condition when we reset the default pub(crate) recommendation to pub(super), I think it's worth it (after refactoring).

r? @petrochenkov

I've reduced it all to a single (somewhat small) if, not sure if it's better, but it's much less verbose as asked.

Have you done a stage 2 build so that the new behaviour is applied to the compiler's own code? Presumably it would require making a lot of additional changes, because warn(unreachable_pub) is used in most of the compiler's own crates.

I haven't tested it on the compiler but as said in #132426 (comment) I have tested it for core, alloc, panic_unwind and std; and since then I have also successfully tested it on hyper, html5ever and itertools, no issues automatically applying the suggestions.

How many changes were necessary?

I don't really understand the question, but what I did is just a cargo fix (or equivalent) for each of them with RUSTFLAGS="-Wunreachable_pub".

I didn't have to fix anything after the cargo fix¹. The pub(super) were all as far as I can tell functional.

The question is how big is the diff obtained when running cargo fix? I.e. how many pub(crate) occurrences were changed to pub(super)? My guess is there would be a lot.

After discussing on Zulip: I was mistakenly thinking that this would suggest pub(super) for pub(crate) occurrences, but it only suggests pub(super) for pub occurrences. So I have no objections to that.

@bors r+

📌 Commit 0bc622d has been approved by petrochenkov

It is now in the queue for this repository.