globally introduce #![deny(unreachable_pub)]

[Rustin170506]

close #2730

I know we don't want to use pub(crate) in pub(crate) struct, but it looks like this lint suggests we do. Do you have any comments on how to handle it?

[kinnison]

I'm not sure what the right answer is here - the extra (crate) is entirely redundant as far as I understand it. Perhaps we need to check in with that lint author to find out?

[Rustin170506]

@Nemo157 I remember you helped to modify this lint last year, do you have any suggestions for using create field in the crate structure? Thanks!

[Nemo157]

🤔 I did? I don't remember that. It does make sense to me that fields could be excluded from this lint, they are not items which are what it's meant to lint against, but it also makes some sense to lint against them too and have a fully consistent "pub means external users can access it" so that locally you can tell whether things are part of the public API (though this matters less for this usecase where it looks like the unreachable_pub lint is being used as a manual implementation of rust-lang/rust#74970).

[Rustin170506]

Maybe this doesn't make much sense for field checking. So I close it.