doc(hidden) stopped working in binary crates

[dtolnay]

rust-lang/cargo#7593 seems relevant. cc @LukasKalbertodt @Eh2406

If I have the following binary crate, cargo doc on stable 1.40.0 will correctly show g and not f, while beta will show both despite f being doc(hidden).

#[doc(hidden)]
pub fn f() {}
pub fn g() {}
fn main() {}

I understand that we want private things documented for bin crates, but I am labeling this a regression because this makes it impossible for macro-generated code to hide distracting implementation details that might overwhelm the actual useful API of the generated code.

I would like to suggest continuing to leave doc(hidden) items out of bin crate documentation as the default behavior of cargo doc.

[Eh2406]

Your suggestion seems entirely reasonable to me. I don't know what PR wuld need to go where to impl it.

[dtolnay]

@rust-lang/cargo @rust-lang/rustdoc, any tips for what PRs would need to go where?

[LukasKalbertodt]

Just for reference, the PR you linked (rust-lang/cargo#7593) is not directly responsible for the buggy behavior. You can see the problem with 1.40 by cargo doc --document-private-items (which also documents f).

Could it be that we simply have to add a STRIP_HIDDEN pass here (and potentially some other arrays in that file)?

rust/src/librustdoc/passes/mod.rs

Lines 89 to 98 in e845e69

	pub const DEFAULT_PRIVATE_PASSES: &[Pass] = &[
	COLLECT_TRAIT_IMPLS,
	COLLAPSE_DOCS,
	UNINDENT_COMMENTS,
	CHECK_PRIVATE_ITEMS_DOC_TESTS,
	STRIP_PRIV_IMPORTS,
	COLLECT_INTRA_DOC_LINKS,
	CHECK_CODE_BLOCK_SYNTAX,
	PROPAGATE_DOC_CFG,
	];

[jtmoon79]

Relates to #66528