Linting public reexport of private dependencies

[mladedav]

Part of public/private dependencies #44663
Partially addresses #71043

I'm adding a warning for reexports of private dependencies into rustc_resolve. I get that this should not be a warning, but should instead be a lint to be controlled by the feature gate, but I did not figure out how exactly to do that at that point. I tried doing the same thing as is done in rustc_privacy, but the linting system is not ready yet as far as I understand the error I got, so I made a warning for now instead. Some guidance on how to emit lints with dcx would be appreciated.

This also sets the std_detect crate as a public dependency of std because some macros are reexported from there. I did not check closer, but the other option may be to allow the specific reexports instead.

[rustbot]

r? @compiler-errors

rustbot has assigned @compiler-errors.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[compiler-errors]

r? petrochenkov perhaps

[bors]

☔ The latest upstream changes (presumably #143888) made this pull request unmergeable. Please resolve the merge conflicts.

[petrochenkov]

I'm adding a warning for reexports of private dependencies into rustc_resolve. I get that this should not be a warning, but should instead be a lint to be controlled by the feature gate, but I did not figure out how exactly to do that at that point. I tried doing the same thing as is done in rustc_privacy, but the linting system is not ready yet as far as I understand the error I got, so I made a warning for now instead. Some guidance on how to emit lints with dcx would be appreciated.

See calls to buffer_lint in rustc_resolve, they can be used as examples.

[petrochenkov]

It's better to move the lint logic to check_hidden_glob_reexports.

That function already has a very similar logic for iterating over bindings.
And also the effective visibility table is already populated there so you can do checks like self.effective_visibilities.is_exported(def_id) instead of just relying on pub and getting false positives.

[mladedav]

I moved it there.

Should I rename the function to something like check_reexports? I can't think of anything more specific but it already wasn't checking just for hidden globs and now I feel I'm making the naming situation worse.

[mladedav]

@rustbot label -S-waiting-on-author +S-waiting-on-review