rustdoc is parsing email link literals in docs as intradoc links in the latest nightly

[lopopolo]

I tried this code:

/// Information about an Artichoke build.
///
/// Implementations of this trait are used to set global Ruby constants that
/// describe the current build.
pub trait ReleaseMetadata {
    /// Copyright information.
    ///
    /// This value will populate the `RUBY_COPYRIGHT` constant.
    ///
    /// # Examples
    ///
    /// > artichoke - Copyright (c) 2019-2020 Ryan Lopopolo <rjl@hyperbo.la>
    fn ruby_copyright(&self) -> &str;
}

I expected to see this happen: rustdoc parses the link as an email address and renders it as a mailto: link.

Instead, this happened:

• https://twitter.com/artichokeruby/status/1378788852261736450
• Escape email from example docs for ReleaseMetadata::ruby_copyright artichoke/artichoke#1152

error: unknown disambiguator `rjl`
  --> artichoke-core/src/release_metadata.rs:18:62
   |
18 |     /// > artichoke - Copyright (c) 2019-2020 Ryan Lopopolo <rjl@hyperbo.la>
   |                                                              ^^^
   |
   = note: requested on the command line with `-D rustdoc::broken-intra-doc-links`

Meta

/usr/share/rust/.cargo/bin/rustup show
Default host: x86_64-unknown-linux-gnu
rustup home:  /home/runner/.rustup

info: syncing channel updates for '1.51.0-x86_64-unknown-linux-gnu'
info: latest update on 2021-03-25, rust version 1.51.0 (2fd73fabe 2021-03-23)
info: downloading component 'cargo'
info: downloading component 'rust-std'
info: downloading component 'rustc'
info: installing component 'cargo'
info: using up to 500.0 MiB of RAM to unpack components
info: installing component 'rust-std'
info: installing component 'rustc'
1.51.0-x86_64-unknown-linux-gnu (overridden by '/home/runner/work/artichoke/artichoke/rust-toolchain')
rustc 1.51.0 (2fd73fabe 2021-03-23)
/usr/share/rust/.cargo/bin/rustup -V
rustup 1.23.1 (3df2264a9 2020-11-30)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `rustc 1.51.0 (2fd73fabe 2021-03-23)`
Installed rustup 1.23.1 support profiles
/usr/share/rust/.cargo/bin/rustup set profile minimal
info: profile set to 'minimal'
/usr/share/rust/.cargo/bin/rustup toolchain install nightly
info: syncing channel updates for 'nightly-x86_64-unknown-linux-gnu'
info: latest update on 2021-04-04, rust version 1.53.0-nightly (0b417ab5c 2021-04-03)
info: downloading component 'cargo'
info: downloading component 'rust-std'
info: downloading component 'rustc'
info: installing component 'cargo'
info: using up to 500.0 MiB of RAM to unpack components
info: installing component 'rust-std'
info: installing component 'rustc'

  nightly-x86_64-unknown-linux-gnu installed - rustc 1.53.0-nightly (0b417ab5c 2021-04-03)

info: checking for self-updates
/usr/share/rust/.cargo/bin/rustup override set nightly
info: using existing install for 'nightly-x86_64-unknown-linux-gnu'
info: override toolchain for '/home/runner/work/artichoke/artichoke' set to 'nightly-x86_64-unknown-linux-gnu'

  nightly-x86_64-unknown-linux-gnu unchanged - rustc 1.53.0-nightly (0b417ab5c 2021-04-03)

(from a GitHub Actions run, the latest nightly won't install on my Arch box due to broken components)

[lopopolo]

This turned out to be a bug in my docs; I didn't intend for this to be rendered as a mailto: link, but I was hoping for a better error message.

[lopopolo]

I think this PR introduced this new behavior: #83543.

[jyn514]

This is weird - rustdoc should be ignoring any link that has . in it:

rust/src/librustdoc/passes/collect_intra_doc_links.rs

Line 988 in 8ad6a44

if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;".contains(ch))) {

[jyn514]

Ah I see the issue - disambiguator_error should only be reported if the link isn't ignored. @camelid do you have time to fix it? It should be as simple as adding the same check here:

rust/src/librustdoc/passes/collect_intra_doc_links.rs

Line 983 in 8ad6a44

disambiguator_error(self.cx, &item, dox, disambiguator_range, &err_msg);

[camelid]

Assigning P-medium and removing I-prioritize as discussed in the prioritization working group.

@rustbot label: +P-medium -I-prioritize