Remove disambiguators from link text

Related to rust-lang#65354

- Pass through the replacement text to `markdown.rs`
- Add some tests
- Add a state machine that actually replaces the text when parsing Markdown

Author: jyn514

src/librustdoc/clean/types.rs

@@ -436,6 +436,11 @@ pub struct Attributes {
 pub struct ItemLink {
     /// The original link written in the markdown
     pub(crate) link: String,
+    /// The link text displayed in the HTML.
+    ///
+    /// This may not be the same as `link` if there was a disambiguator
+    /// in an intra-doc link (e.g. [`fn@f`])
+    pub(crate) link_text: String,
     pub(crate) did: Option<DefId>,
     /// The url fragment to append to the link
     pub(crate) fragment: Option<String>,
@@ -444,6 +449,8 @@ pub struct ItemLink {
 pub struct RenderedLink {
     /// The text the link was original written as
     pub(crate) original_text: String,
+    /// The text to display in the HTML
+    pub(crate) new_text: String,
     /// The URL to put in the `href`
     pub(crate) href: String,
 }
@@ -630,15 +637,19 @@ impl Attributes {
 
         self.links
             .iter()
-            .filter_map(|ItemLink { link: s, did, fragment }| {
+            .filter_map(|ItemLink { link: s, link_text, did, fragment }| {
                 match *did {
                     Some(did) => {
                         if let Some((mut href, ..)) = href(did) {
                             if let Some(ref fragment) = *fragment {
                                 href.push_str("#");
                                 href.push_str(fragment);
                             }
-                            Some(RenderedLink { original_text: s.clone(), href })
+                            Some(RenderedLink {
+                                original_text: s.clone(),
+                                new_text: link_text.clone(),
+                                href,
+                            })
                         } else {
                             None
                         }
@@ -660,6 +671,7 @@ impl Attributes {
                             let tail = fragment.find('#').unwrap_or_else(|| fragment.len());
                             Some(RenderedLink {
                                 original_text: s.clone(),
+                                new_text: link_text.clone(),
                                 href: format!(
                                     "{}{}std/primitive.{}.html{}",
                                     url,

src/librustdoc/html/markdown.rs

@@ -340,29 +340,86 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
 /// Make headings links with anchor IDs and build up TOC.
 struct LinkReplacer<'a, 'b, I: Iterator<Item = Event<'a>>> {
     inner: I,
-    links: &'b [RenderedLink],
+    links: &'a [RenderedLink],
+    shortcut_link: Option<&'b RenderedLink>,
 }
 
-impl<'a, 'b, I: Iterator<Item = Event<'a>>> LinkReplacer<'a, 'b, I> {
-    fn new(iter: I, links: &'b [RenderedLink]) -> Self {
-        LinkReplacer { inner: iter, links }
+impl<'a, I: Iterator<Item = Event<'a>>> LinkReplacer<'a, '_, I> {
+    fn new(iter: I, links: &'a [RenderedLink]) -> Self {
+        LinkReplacer { inner: iter, links, shortcut_link: None }
     }
 }
 
-impl<'a, 'b, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, 'b, I> {
+impl<'a: 'b, 'b, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, 'b, I> {
     type Item = Event<'a>;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let event = self.inner.next();
-        if let Some(Event::Start(Tag::Link(kind, dest, text))) = event {
-            if let Some(link) = self.links.iter().find(|link| link.original_text == *dest) {
-                Some(Event::Start(Tag::Link(kind, link.href.clone().into(), text)))
-            } else {
-                Some(Event::Start(Tag::Link(kind, dest, text)))
+        let mut event = self.inner.next();
+
+        // Remove disambiguators from shortcut links (`[fn@f]`)
+        match &mut event {
+            Some(Event::Start(Tag::Link(
+                pulldown_cmark::LinkType::ShortcutUnknown,
+                dest,
+                title,
+            ))) => {
+                debug!("saw start of shortcut link to {} with title {}", dest, title);
+                let link = if let Some(link) =
+                    self.links.iter().find(|&link| *link.original_text == **dest)
+                {
+                    // Not sure why this is necessary - maybe the broken_link_callback doesn't always work?
+                    *dest = CowStr::Borrowed(link.href.as_ref());
+                    Some(link)
+                } else {
+                    self.links.iter().find(|&link| *link.href == **dest)
+                };
+                if let Some(link) = link {
+                    trace!("it matched");
+                    assert!(self.shortcut_link.is_none(), "shortcut links cannot be nested");
+                    self.shortcut_link = Some(link);
+                }
             }
-        } else {
-            event
+            Some(Event::End(Tag::Link(pulldown_cmark::LinkType::ShortcutUnknown, dest, _))) => {
+                debug!("saw end of shortcut link to {}", dest);
+                if let Some(_link) = self.links.iter().find(|&link| *link.href == **dest) {
+                    assert!(self.shortcut_link.is_some(), "saw closing link without opening tag");
+                    self.shortcut_link = None;
+                }
+            }
+            // Handle backticks in inline code blocks
+            Some(Event::Code(text)) => {
+                trace!("saw code {}", text);
+                if let Some(link) = self.shortcut_link {
+                    trace!("original text was {}", link.original_text);
+                    if **text == link.original_text[1..link.original_text.len() - 1] {
+                        debug!("replacing {} with {}", text, link.new_text);
+                        *text = link.new_text.clone().into();
+                    }
+                }
+            }
+            // Replace plain text in links
+            Some(Event::Text(text)) => {
+                trace!("saw text {}", text);
+                if let Some(link) = self.shortcut_link {
+                    trace!("original text was {}", link.original_text);
+                    if **text == *link.original_text {
+                        debug!("replacing {} with {}", text, link.new_text);
+                        *text = link.new_text.clone().into();
+                    }
+                }
+            }
+            Some(Event::Start(Tag::Link(_, dest, _))) => {
+                if let Some(link) = self.links.iter().find(|&link| *link.original_text == **dest) {
+                    // Not sure why this is necessary - maybe the broken_link_callback doesn't always work?
+                    *dest = CowStr::Borrowed(link.href.as_ref());
+                }
+            }
+            // Anything else couldn't have been a valid Rust path
+            _ => {}
         }
+
+        // Yield the modified event
+        event
     }
 }
 
@@ -857,7 +914,7 @@ impl Markdown<'_> {
         }
         let replacer = |_: &str, s: &str| {
             if let Some(link) = links.iter().find(|link| &*link.original_text == s) {
-                Some((link.original_text.clone(), link.href.clone()))
+                Some((link.href.clone(), link.new_text.clone()))
             } else {
                 None
             }
@@ -934,8 +991,8 @@ impl MarkdownSummaryLine<'_> {
         }
 
         let replacer = |_: &str, s: &str| {
-            if let Some(rendered_link) = links.iter().find(|link| &*link.original_text == s) {
-                Some((rendered_link.original_text.clone(), rendered_link.href.clone()))
+            if let Some(link) = links.iter().find(|link| &*link.original_text == s) {
+                Some((link.href.clone(), link.new_text.clone()))
             } else {
                 None
             }

src/librustdoc/html/render/mod.rs

@@ -64,8 +64,7 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 
 use crate::clean::{self, AttributesExt, Deprecation, GetDefId, RenderedLink, SelfTy, TypeKind};
-use crate::config::RenderInfo;
-use crate::config::RenderOptions;
+use crate::config::{RenderInfo, RenderOptions};
 use crate::docfs::{DocFS, PathError};
 use crate::doctree;
 use crate::error::Error;

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -685,6 +685,7 @@ impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
                 continue;
             }
 
+            //let had_backticks = ori_link.contains("`");
             let link = ori_link.replace("`", "");
             let parts = link.split('#').collect::<Vec<_>>();
             let (link, extra_fragment) = if parts.len() > 2 {
@@ -700,6 +701,7 @@ impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
                 (parts[0], None)
             };
             let resolved_self;
+            let link_text;
             let mut path_str;
             let disambiguator;
             let (mut res, mut fragment) = {
@@ -716,6 +718,12 @@ impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
                     continue;
                 }
 
+                // We stripped ` characters for `path_str`.
+                // The original link might have had multiple pairs of backticks,
+                // but we don't handle this case.
+                //link_text = if had_backticks { format!("`{}`", path_str) } else { path_str.to_owned() };
+                link_text = path_str.to_owned();
+
                 // In order to correctly resolve intra-doc-links we need to
                 // pick a base AST node to work from.  If the documentation for
                 // this module came from an inner comment (//!) then we anchor
@@ -904,7 +912,12 @@ impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
             if let Res::PrimTy(_) = res {
                 match disambiguator {
                     Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {
-                        item.attrs.links.push(ItemLink { link: ori_link, did: None, fragment });
+                        item.attrs.links.push(ItemLink {
+                            link: ori_link,
+                            link_text: path_str.to_owned(),
+                            did: None,
+                            fragment,
+                        });
                     }
                     Some(other) => {
                         report_mismatch(other, Disambiguator::Primitive);
@@ -955,7 +968,12 @@ impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
                     }
                 }
                 let id = register_res(cx, res);
-                item.attrs.links.push(ItemLink { link: ori_link, did: Some(id), fragment });
+                item.attrs.links.push(ItemLink {
+                    link: ori_link,
+                    link_text,
+                    did: Some(id),
+                    fragment,
+                });
             }
         }
 

src/test/rustdoc/disambiguator_removed.rs

@@ -0,0 +1,33 @@
+#![deny(intra_doc_link_resolution_failure)]
+// first try backticks
+/// Trait: [`trait@Name`], fn: [`fn@Name`], [`Name`][`macro@Name`]
+// @has disambiguator_removed/struct.AtDisambiguator.html
+// @has - '//a[@href="../disambiguator_removed/trait.Name.html"][code]' "Name"
+// @has - '//a[@href="../disambiguator_removed/fn.Name.html"][code]' "Name"
+// @has - '//a[@href="../disambiguator_removed/macro.Name.html"][code]' "Name"
+pub struct AtDisambiguator;
+
+/// fn: [`Name()`], macro: [`Name!`]
+// @has disambiguator_removed/struct.SymbolDisambiguator.html
+// @has - '//a[@href="../disambiguator_removed/fn.Name.html"][code]' "Name()"
+// @has - '//a[@href="../disambiguator_removed/macro.Name.html"][code]' "Name!"
+pub struct SymbolDisambiguator;
+
+// Now make sure that backticks aren't added if they weren't already there
+/// [fn@Name]
+// @has disambiguator_removed/trait.Name.html
+// @has - '//a[@href="../disambiguator_removed/fn.Name.html"]' "Name"
+// @!has - '//a[@href="../disambiguator_removed/fn.Name.html"][code]' "Name"
+
+// FIXME: this will turn !() into ! alone
+/// [Name!()]
+// @has - '//a[@href="../disambiguator_removed/macro.Name.html"]' "Name!"
+pub trait Name {}
+
+#[allow(non_snake_case)]
+pub fn Name() {}
+
+#[macro_export]
+macro_rules! Name {
+    () => ()
+}