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};
@@ -428,6 +428,14 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
                 ) => {
                     vec![(Res::from_def_id(self.cx.tcx, self.cx.tcx.parent(def_id)), Some(def_id))]
                 }
+                Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => {
+                    let def_id = self.cx.tcx.parent(def_id);
+                    vec![(Res::from_def_id(self.cx.tcx, self.cx.tcx.parent(def_id)), Some(def_id))]
+                }
+                Res::Def(DefKind::Ctor(CtorOf::Struct, _), def_id) => {
+                    let def_id = self.cx.tcx.parent(def_id);
+                    vec![(Res::from_def_id(self.cx.tcx, def_id), None)]
+                }
                 _ => vec![(res, None)],
             });
         } else if ns == MacroNS {

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

@@ -0,0 +1,23 @@
+// https://github.com/rust-lang/rust/issues/130591
+#![deny(rustdoc::broken_intra_doc_links)]
+#![crate_name = "foo"]
+
+pub enum MyEnum {
+    Internals,
+}
+
+pub use MyEnum::*;
+
+/// [Internals] //~ERROR `Internals` is both
+pub struct Internals {
+    foo: (),
+}
+
+pub mod inside {
+    pub struct Internals2;
+}
+
+use inside::*;
+
+/// [Internals2] //~ERROR `Internals2` is both
+pub enum Internals2 {}

tests/rustdoc-ui/intra-doc/value-ctor-disambig.stderr

@@ -0,0 +1,37 @@
+error: `Internals` is both a variant and a struct
+  --> $DIR/value-ctor-disambig.rs:11:6
+   |
+LL | /// [Internals]
+   |      ^^^^^^^^^ ambiguous link
+   |
+note: the lint level is defined here
+  --> $DIR/value-ctor-disambig.rs:2:9
+   |
+LL | #![deny(rustdoc::broken_intra_doc_links)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: to link to the variant, prefix with `variant@`
+   |
+LL | /// [variant@Internals]
+   |      ++++++++
+help: to link to the struct, prefix with `struct@`
+   |
+LL | /// [struct@Internals]
+   |      +++++++
+
+error: `Internals2` is both a struct and an enum
+  --> $DIR/value-ctor-disambig.rs:22:6
+   |
+LL | /// [Internals2]
+   |      ^^^^^^^^^^ ambiguous link
+   |
+help: to link to the struct, prefix with `struct@`
+   |
+LL | /// [struct@Internals2]
+   |      +++++++
+help: to link to the enum, prefix with `enum@`
+   |
+LL | /// [enum@Internals2]
+   |      +++++
+
+error: aborting due to 2 previous errors
+

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 {}