Rustdoc can generate wrong macro_rules! syntax

[jonas-schievink]

Example: https://docs.rs/pkg-version/0.1.0/pkg_version/macro.pkg_version_minor.html

The source code looks like this:

#[proc_macro_hack]
pub use pkg_version_impl::pkg_version_minor;

The rustdoc output looks like this:

macro_rules! pkg_version_minor {
    #[proc_macro_hack] => { ... };
}

Now I'm not entirely sure how #[proc_macro_hack] works, but I don't think rustdoc should ever produce... this? The matcher is syntactically invalid, so this should never really happen.

Perhaps related to #45939, but I'm not sure.

[dtolnay]

Fixed in nightly-2021-07-06, likely by #86282.

[dtolnay]

The new rustdoc shows:

macro_rules! pkg_version_minor {
    ($($proc_macro : tt) *) => { ... };
}