You can pass a string literal to `#[doc(hidden = "foo")]`. Is this intended?

[nik-rev]

The docs don't mention this. Is it supposed to represent the reason why the item is hidden, or was it an oversight?

12 instances of this on GitHub: https://github.com/search?q=%2F%23%5C%5Bdoc%5C(hidden%20%3D%20%22%2F&type=code

[zachs18]

Note that this string does not show up in the rendered documentation when using the (unstable) --document-hidden-items:

cargo new --lib doc-priv && cd doc-priv

// lib.rs
#[doc(hidden = "for some reason")]
pub fn __foo() {}

RUSTDOCFLAGS="-Zunstable-options --document-hidden-items" cargo +nightly doc --open