Rollup merge of #80660 - max-heller:issue-80559-fix, r=jyn514

Properly handle primitive disambiguators in rustdoc

Fixes #80559

r? ``@jyn514``

Is there a way to test that the generated intra-doc link is what I expect?

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -394,10 +394,14 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
                         ns,
                         impl_,
                     )
-                    .map(|item| match item.kind {
+                    .map(|item| {
+                        let kind = item.kind;
+                        self.kind_side_channel.set(Some((kind.as_def_kind(), item.def_id)));
+                        match kind {
                             ty::AssocKind::Fn => "method",
                             ty::AssocKind::Const => "associatedconstant",
                             ty::AssocKind::Type => "associatedtype",
+                        }
                     })
                     .map(|out| {
                         (
@@ -1142,17 +1146,8 @@ impl LinkCollector<'_, '_> {
                 callback,
             );
         };
-        match res {
-            Res::Primitive(_) => match disambiguator {
-                Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {
-                    Some(ItemLink { link: ori_link.link, link_text, did: None, fragment })
-                }
-                Some(other) => {
-                    report_mismatch(other, Disambiguator::Primitive);
-                    None
-                }
-            },
-            Res::Def(kind, id) => {
+
+        let verify = |kind: DefKind, id: DefId| {
             debug!("intra-doc link to {} resolved to {:?}", path_str, res);
 
             // Disallow e.g. linking to enums with `struct@`
@@ -1191,6 +1186,35 @@ impl LinkCollector<'_, '_> {
                     privacy_error(cx, &item, &path_str, dox, &ori_link);
                 }
             }
+
+            Some((kind, id))
+        };
+
+        match res {
+            Res::Primitive(_) => {
+                if let Some((kind, id)) = self.kind_side_channel.take() {
+                    // We're actually resolving an associated item of a primitive, so we need to
+                    // verify the disambiguator (if any) matches the type of the associated item.
+                    // This case should really follow the same flow as the `Res::Def` branch below,
+                    // but attempting to add a call to `clean::register_res` causes an ICE. @jyn514
+                    // thinks `register_res` is only needed for cross-crate re-exports, but Rust
+                    // doesn't allow statements like `use str::trim;`, making this a (hopefully)
+                    // valid omission. See https://github.com/rust-lang/rust/pull/80660#discussion_r551585677
+                    // for discussion on the matter.
+                    verify(kind, id)?;
+                } else {
+                    match disambiguator {
+                        Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {}
+                        Some(other) => {
+                            report_mismatch(other, Disambiguator::Primitive);
+                            return None;
+                        }
+                    }
+                }
+                Some(ItemLink { link: ori_link.link, link_text, did: None, fragment })
+            }
+            Res::Def(kind, id) => {
+                let (kind, id) = verify(kind, id)?;
                 let id = clean::register_res(cx, rustc_hir::def::Res::Def(kind, id));
                 Some(ItemLink { link: ori_link.link, link_text, did: Some(id), fragment })
             }

src/test/rustdoc-ui/intra-doc/incompatible-primitive-disambiguator.rs

@@ -0,0 +1,3 @@
+#![deny(broken_intra_doc_links)]
+//! [static@u8::MIN]
+//~^ ERROR incompatible link kind

src/test/rustdoc-ui/intra-doc/incompatible-primitive-disambiguator.stderr

@@ -0,0 +1,15 @@
+error: incompatible link kind for `u8::MIN`
+  --> $DIR/incompatible-primitive-disambiguator.rs:2:6
+   |
+LL | //! [static@u8::MIN]
+   |      ^^^^^^^^^^^^^^ help: to link to the associated constant, prefix with `const@`: `const@u8::MIN`
+   |
+note: the lint level is defined here
+  --> $DIR/incompatible-primitive-disambiguator.rs:1:9
+   |
+LL | #![deny(broken_intra_doc_links)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+   = note: this link resolved to an associated constant, which is not a static
+
+error: aborting due to previous error
+

src/test/rustdoc/intra-doc/primitive-disambiguators.rs

@@ -0,0 +1,4 @@
+#![deny(broken_intra_doc_links)]
+// @has primitive_disambiguators/index.html
+// @has - '//a/@href' 'https://doc.rust-lang.org/nightly/std/primitive.str.html#method.trim'
+//! [str::trim()]