rustdoc: linking to a local proc macro no longer warns

fixes #91274 tried to keep the fix general in case we ever have any other kind of item that occupies multiple namespaces simultaniously.

Author: lolbinarycat

src/librustdoc/lib.rs

@@ -17,6 +17,7 @@
 #![feature(test)]
 #![feature(type_alias_impl_trait)]
 #![feature(type_ascription)]
+#![feature(iterator_try_reduce)]
 #![recursion_limit = "256"]
 #![warn(rustc::internal)]
 #![allow(clippy::collapsible_if, clippy::collapsible_else_if)]

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -2219,6 +2219,17 @@ fn report_malformed_generics(
  );
 }
 
+fn refer_to_single_item(v: &[Res]) -> bool {
+ // proc macros can exist in multiple namespaces at once,
+ // so we need to compare DefIds
+ v.iter()
+ .try_reduce(|l, r| match (l, r) {
+ (Res::Def(_, lid), Res::Def(_, rid)) if lid == rid => Some(l),
+ _ => None,
+ })
+ .is_some()
+}
+
 /// Report an ambiguity error, where there were multiple possible resolutions.
 ///
 /// If all `candidates` have the same kind, it's not possible to disambiguate so in this case,
@@ -2241,7 +2252,7 @@ fn ambiguity_error(
  )
  .filter(|res| descrs.insert(res.descr()))
  .collect::<Vec<_>>();
- if descrs.len() == 1 {
+ if descrs.len() == 1 || refer_to_single_item(&kinds) {
  // There is no way for users to disambiguate at this point, so better return the first
  // candidate and not show a warning.
  return false;

tests/rustdoc/intra-doc/link-to-proc-macro.rs

@@ -0,0 +1,13 @@
+//@ compile-flags: --crate-type=proc-macro
+//@ has 'foo/index.html' '//a[@href="macro.my_macro.html"]' 'my_macro'
+//! Link to [`my_macro`].
+#![crate_name = "foo"]
+
+// regression test for https://github.com/rust-lang/rust/issues/91274
+
+extern crate proc_macro;
+
+#[proc_macro]
+pub fn my_macro(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+ input
+}