rustdoc: correctly resolve link disambiguators through ctors

Author: notriddle

src/librustdoc/clean/utils.rs

@@ -503,6 +503,7 @@ pub(crate) fn synthesize_auto_trait_and_blanket_impls(
 /// [`href()`]: crate::html::format::href
 pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
     use DefKind::*;
+    use rustc_hir::def::CtorOf;
     debug!("register_res({res:?})");
 
     let (kind, did) = match res {
@@ -526,6 +527,22 @@ pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
             did,
         ) => (kind.into(), did),
 
+        // Tuple and unit-like structs and enums exist in both type and
+        // value ns. The item that exists in value ns is the "constructor,"
+        // a special function or const that returns the constructed value.
+        //
+        // It's possible to make an intra-doc link that points at the
+        // constructor, but it's not actually documented separately from
+        // the type itself.
+        Res::Def(Ctor(ctor_of, _), did) => (
+            match ctor_of {
+                CtorOf::Struct => Struct,
+                CtorOf::Variant => Variant,
+            }
+            .into(),
+            cx.tcx.parent(did),
+        ),
+
         _ => panic!("register_res: unexpected {res:?}"),
     };
     if did.is_local() {

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -13,7 +13,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::intern::Interned;
 use rustc_errors::{Applicability, Diag, DiagMessage};
 use rustc_hir::def::Namespace::*;
-use rustc_hir::def::{DefKind, Namespace, PerNS};
+use rustc_hir::def::{CtorOf, DefKind, Namespace, PerNS};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
 use rustc_hir::{Mutability, Safety};
 use rustc_middle::ty::{Ty, TyCtxt};
@@ -212,7 +212,7 @@ impl UrlFragment {
                     }
                     DefKind::AssocConst => "associatedconstant.",
                     DefKind::AssocTy => "associatedtype.",
-                    DefKind::Variant => "variant.",
+                    DefKind::Variant | DefKind::Ctor(CtorOf::Variant, _) => "variant.",
                     DefKind::Field => {
                         let parent_id = tcx.parent(def_id);
                         if tcx.def_kind(parent_id) == DefKind::Variant {
@@ -423,7 +423,11 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
         if let Some(res) = self.resolve_path(path_str, ns, item_id, module_id) {
             return Ok(match res {
                 Res::Def(
-                    DefKind::AssocFn | DefKind::AssocConst | DefKind::AssocTy | DefKind::Variant,
+                    DefKind::AssocFn
+                    | DefKind::AssocConst
+                    | DefKind::AssocTy
+                    | DefKind::Variant
+                    | DefKind::Ctor(CtorOf::Variant, _),
                     def_id,
                 ) => {
                     vec![(Res::from_def_id(self.cx.tcx, self.cx.tcx.parent(def_id)), Some(def_id))]

tests/rustdoc/intra-doc/value-ctor.rs

@@ -0,0 +1,37 @@
+// https://github.com/rust-lang/rust/issues/130591
+#![deny(rustdoc::broken_intra_doc_links)]
+#![crate_name = "foo"]
+
+/// [value@Foo::X]
+//@ has foo/enum.Foo.html '//a[@href="enum.Foo.html#variant.X"]' 'Foo::X'
+pub enum Foo {
+    X,
+}
+
+/// [tst][value@MyStruct]
+//@ has foo/struct.MyStruct.html '//a[@href="struct.MyStruct.html"]' 'tst'
+pub struct MyStruct;
+
+pub enum MyEnum {
+    Internals,
+}
+
+pub use MyEnum::*;
+
+/// In this context, [a][type@Internals] is a struct, while [b][value@Internals] is an enum variant.
+//@ has foo/struct.Internals.html '//a[@href="struct.Internals.html"]' 'a'
+//@ has foo/struct.Internals.html '//a[@href="enum.MyEnum.html#variant.Internals"]' 'b'
+pub struct Internals {
+    foo: (),
+}
+
+pub mod inside {
+    pub struct Internals2;
+}
+
+use inside::*;
+
+/// In this context, [a][type@Internals2] is an enum, while [b][value@Internals2] is a struct.
+//@ has foo/enum.Internals2.html '//a[@href="enum.Internals2.html"]' 'a'
+//@ has foo/enum.Internals2.html '//a[@href="inside/struct.Internals2.html"]' 'b'
+pub enum Internals2 {}