Auto merge of #113167 - ChAoSUnItY:redundant_explicit_link, r=GuillaumeGomez

rustdoc: Add lint `redundant_explicit_links`

Closes #87799.
- Lint warns by default
- Reworks link parser to cache original link's display text

r? `@jyn514`

compiler/rustc_borrowck/src/consumers.rs

@@ -30,7 +30,7 @@ pub use super::{
 /// will be retrieved.
 #[derive(Debug, Copy, Clone)]
 pub enum ConsumerOptions {
-    /// Retrieve the [`Body`] along with the [`BorrowSet`](super::borrow_set::BorrowSet)
+    /// Retrieve the [`Body`] along with the [`BorrowSet`]
     /// and [`RegionInferenceContext`]. If you would like the body only, use
     /// [`TyCtxt::mir_promoted`].
     ///

compiler/rustc_errors/src/lib.rs

@@ -452,11 +452,11 @@ struct HandlerInner {
     /// have been converted.
     check_unstable_expect_diagnostics: bool,
 
-    /// Expected [`Diagnostic`][diagnostic::Diagnostic]s store a [`LintExpectationId`] as part of
+    /// Expected [`Diagnostic`][struct@diagnostic::Diagnostic]s store a [`LintExpectationId`] as part of
     /// the lint level. [`LintExpectationId`]s created early during the compilation
     /// (before `HirId`s have been defined) are not stable and can therefore not be
     /// stored on disk. This buffer stores these diagnostics until the ID has been
-    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`][diagnostic::Diagnostic]s are the
+    /// replaced by a stable [`LintExpectationId`]. The [`Diagnostic`][struct@diagnostic::Diagnostic]s are the
     /// submitted for storage and added to the list of fulfilled expectations.
     unstable_expect_diagnostics: Vec<Diagnostic>,
 

compiler/rustc_resolve/src/rustdoc.rs

@@ -1,4 +1,4 @@
-use pulldown_cmark::{BrokenLink, Event, LinkType, Options, Parser, Tag};
+use pulldown_cmark::{BrokenLink, CowStr, Event, LinkType, Options, Parser, Tag};
 use rustc_ast as ast;
 use rustc_ast::util::comments::beautify_doc_string;
 use rustc_data_structures::fx::FxHashMap;
@@ -392,16 +392,73 @@ pub(crate) fn attrs_to_preprocessed_links(attrs: &[ast::Attribute]) -> Vec<Box<s
     let (doc_fragments, _) = attrs_to_doc_fragments(attrs.iter().map(|attr| (attr, None)), true);
     let doc = prepare_to_doc_link_resolution(&doc_fragments).into_values().next().unwrap();
 
-    Parser::new_with_broken_link_callback(
+    parse_links(&doc)
+}
+
+/// Similiar version of `markdown_links` from rustdoc.
+/// This will collect destination links and display text if exists.
+fn parse_links<'md>(doc: &'md str) -> Vec<Box<str>> {
+    let mut broken_link_callback = |link: BrokenLink<'md>| Some((link.reference, "".into()));
+    let mut event_iter = Parser::new_with_broken_link_callback(
         &doc,
         main_body_opts(),
-        Some(&mut |link: BrokenLink<'_>| Some((link.reference, "".into()))),
+        Some(&mut broken_link_callback),
     )
-    .filter_map(|event| match event {
-        Event::Start(Tag::Link(link_type, dest, _)) if may_be_doc_link(link_type) => {
-            Some(preprocess_link(&dest))
+    .into_iter();
+    let mut links = Vec::new();
+
+    while let Some(event) = event_iter.next() {
+        match event {
+            Event::Start(Tag::Link(link_type, dest, _)) if may_be_doc_link(link_type) => {
+                if matches!(
+                    link_type,
+                    LinkType::Inline
+                        | LinkType::ReferenceUnknown
+                        | LinkType::Reference
+                        | LinkType::Shortcut
+                        | LinkType::ShortcutUnknown
+                ) {
+                    if let Some(display_text) = collect_link_data(&mut event_iter) {
+                        links.push(display_text);
+                    }
+                }
+
+                links.push(preprocess_link(&dest));
+            }
+            _ => {}
         }
-        _ => None,
-    })
-    .collect()
+    }
+
+    links
+}
+
+/// Collects additional data of link.
+fn collect_link_data<'input, 'callback>(
+    event_iter: &mut Parser<'input, 'callback>,
+) -> Option<Box<str>> {
+    let mut display_text: Option<String> = None;
+    let mut append_text = |text: CowStr<'_>| {
+        if let Some(display_text) = &mut display_text {
+            display_text.push_str(&text);
+        } else {
+            display_text = Some(text.to_string());
+        }
+    };
+
+    while let Some(event) = event_iter.next() {
+        match event {
+            Event::Text(text) => {
+                append_text(text);
+            }
+            Event::Code(code) => {
+                append_text(code);
+            }
+            Event::End(_) => {
+                break;
+            }
+            _ => {}
+        }
+    }
+
+    display_text.map(String::into_boxed_str)
 }