rustdoc: nested items should not be documented with `--document-private-items`

[GuillaumeGomez]

If we run rustdoc with the --document-private-items option on this code:

pub fn foo() {
    fn bar() {}
}

Both foo and bar are documented, but bar not being accessible outside of foo, it shouldn't be documented.

[compiler-errors]

@GuillaumeGomez probably knows this, but for others seeing this issue, I think it's probably due to #104889 (which was reverted in #107083, and later re-applied in #107000 (comment)).

It has to do with the fact that we're using a HIR visitor now, so we're visiting nested items unconditionally.

[GuillaumeGomez]

Yes I know where it's coming from. 😄

I was just thinking today that since we were going through the whole HIR without checking whether or not we were in a block, all elements inside the block could be visible. Tested and... 😨

Should be pretty easy to fix.

[compiler-errors]

For reference, I put up serde-rs/serde#2426 because this was causing documentation to become really verbose with serde + --document-private-items. If you fix this such that we no longer document those items, we could probably revert that PR.

[GuillaumeGomez]

Indeed. Don't hesitate to come to me if you have such issues with rustdoc. Such problems should definitely not go unnoticed.

[compiler-errors]

Don't hesitate to come to me if you have such issues with rustdoc.

The thing is, it was not particularly clear from the PRs whether this was intentional or not.

[GuillaumeGomez]

Unfortunately it wasn't. The goal was to retrieve the missing impl blocks. But if anything isn't clear, don't hesitate to ask too. 😉