Retire hir::ForeignItemRef.

cjgillot · cjgillot · commit 884232a32b4a · 2025-07-05T14:26:55.000Z
diff --git a/compiler/rustc_ast_lowering/src/index.rs b/compiler/rustc_ast_lowering/src/index.rs
@@ -397,12 +397,8 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         self.visit_nested_impl_item(id);
     }
 
-    fn visit_foreign_item_ref(&mut self, fi: &'hir ForeignItemRef) {
-        // Do not visit the duplicate information in ForeignItemRef. We want to
-        // map the actual nodes, not the duplicate ones in the *Ref.
-        let ForeignItemRef { id, ident: _, span: _ } = *fi;
-
-        self.visit_nested_foreign_item(id);
+    fn visit_foreign_item_ref(&mut self, id: &'hir ForeignItemId) {
+        self.visit_nested_foreign_item(*id);
     }
 
     fn visit_where_predicate(&mut self, predicate: &'hir WherePredicate<'hir>) {
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
@@ -704,14 +704,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
         self.arena.alloc(item)
     }
 
-    fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemRef {
-        hir::ForeignItemRef {
-            id: hir::ForeignItemId { owner_id: self.owner_id(i.id) },
-            // `unwrap` is safe because `ForeignItemKind::MacCall` is the only foreign item kind
-            // without an identifier and it cannot reach here.
-            ident: self.lower_ident(i.kind.ident().unwrap()),
-            span: self.lower_span(i.span),
-        }
+    fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemId {
+        hir::ForeignItemId { owner_id: self.owner_id(i.id) }
     }
 
     fn lower_variant(&mut self, item_kind: &ItemKind, v: &Variant) -> hir::Variant<'hir> {
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
@@ -4137,7 +4137,7 @@ impl<'hir> Item<'hir> {
 
         expect_mod, (Ident, &'hir Mod<'hir>), ItemKind::Mod(ident, m), (*ident, m);
 
-        expect_foreign_mod, (ExternAbi, &'hir [ForeignItemRef]),
+        expect_foreign_mod, (ExternAbi, &'hir [ForeignItemId]),
             ItemKind::ForeignMod { abi, items }, (*abi, items);
 
         expect_global_asm, &'hir InlineAsm<'hir>, ItemKind::GlobalAsm { asm, .. }, asm;
@@ -4314,7 +4314,7 @@ pub enum ItemKind<'hir> {
     /// A module.
     Mod(Ident, &'hir Mod<'hir>),
     /// An external module, e.g. `extern { .. }`.
-    ForeignMod { abi: ExternAbi, items: &'hir [ForeignItemRef] },
+    ForeignMod { abi: ExternAbi, items: &'hir [ForeignItemId] },
     /// Module-level inline assembly (from `global_asm!`).
     GlobalAsm {
         asm: &'hir InlineAsm<'hir>,
@@ -4446,19 +4446,6 @@ impl ForeignItemId {
     }
 }
 
-/// A reference from a foreign block to one of its items. This
-/// contains the item's ID, naturally, but also the item's name and
-/// some other high-level details (like whether it is an associated
-/// type or method, and whether it is public). This allows other
-/// passes to find the impl they want without loading the ID (which
-/// means fewer edges in the incremental compilation graph).
-#[derive(Debug, Clone, Copy, HashStable_Generic)]
-pub struct ForeignItemRef {
-    pub id: ForeignItemId,
-    pub ident: Ident,
-    pub span: Span,
-}
-
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct ForeignItem<'hir> {
     pub ident: Ident,
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
@@ -441,8 +441,8 @@ pub trait Visitor<'v>: Sized {
     fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) -> Self::Result {
         walk_impl_item(self, ii)
     }
-    fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemRef) -> Self::Result {
-        walk_foreign_item_ref(self, ii)
+    fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemId) -> Self::Result {
+        walk_foreign_item_ref(self, *ii)
     }
     fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) -> Self::Result {
         walk_impl_item_ref(self, ii)
@@ -1290,13 +1290,8 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(
     }
 }
 
-pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    foreign_item_ref: &'v ForeignItemRef,
-) -> V::Result {
-    let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;
-    try_visit!(visitor.visit_nested_foreign_item(id));
-    visitor.visit_ident(ident)
+pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, id: ForeignItemId) -> V::Result {
+    visitor.visit_nested_foreign_item(id)
 }
 
 pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -931,8 +931,8 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
 
             check_abi(tcx, it.hir_id(), it.span, abi);
 
-            for item in items {
-                let def_id = item.id.owner_id.def_id;
+            for &item in items {
+                let def_id = item.owner_id.def_id;
 
                 let generics = tcx.generics_of(def_id);
                 let own_counts = generics.own_counts();
@@ -944,13 +944,14 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                         (0, _) => ("const", "consts", None),
                         _ => ("type or const", "types or consts", None),
                     };
+                    let span = tcx.def_span(def_id);
                     struct_span_code_err!(
                         tcx.dcx(),
-                        item.span,
+                        span,
                         E0044,
                         "foreign items may not have {kinds} parameters",
                     )
-                    .with_span_label(item.span, format!("can't have {kinds} parameters"))
+                    .with_span_label(span, format!("can't have {kinds} parameters"))
                     .with_help(
                         // FIXME: once we start storing spans for type arguments, turn this
                         // into a suggestion.
@@ -964,22 +965,23 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                     .emit();
                 }
 
-                let item = tcx.hir_foreign_item(item.id);
-                tcx.ensure_ok().generics_of(item.owner_id);
-                tcx.ensure_ok().type_of(item.owner_id);
-                tcx.ensure_ok().predicates_of(item.owner_id);
+                tcx.ensure_ok().generics_of(def_id);
+                tcx.ensure_ok().type_of(def_id);
+                tcx.ensure_ok().predicates_of(def_id);
                 if tcx.is_conditionally_const(def_id) {
                     tcx.ensure_ok().explicit_implied_const_bounds(def_id);
                     tcx.ensure_ok().const_conditions(def_id);
                 }
-                match item.kind {
-                    hir::ForeignItemKind::Fn(sig, ..) => {
-                        tcx.ensure_ok().codegen_fn_attrs(item.owner_id);
-                        tcx.ensure_ok().fn_sig(item.owner_id);
+                match tcx.def_kind(def_id) {
+                    DefKind::Fn => {
+                        tcx.ensure_ok().codegen_fn_attrs(def_id);
+                        tcx.ensure_ok().fn_sig(def_id);
+                        let item = tcx.hir_foreign_item(item);
+                        let hir::ForeignItemKind::Fn(sig, ..) = item.kind else { bug!() };
                         require_c_abi_if_c_variadic(tcx, sig.decl, abi, item.span);
                     }
-                    hir::ForeignItemKind::Static(..) => {
-                        tcx.ensure_ok().codegen_fn_attrs(item.owner_id);
+                    DefKind::Static { .. } => {
+                        tcx.ensure_ok().codegen_fn_attrs(def_id);
                     }
                     _ => (),
                 }
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
@@ -654,8 +654,8 @@ impl<'a> State<'a> {
                 let (cb, ib) = self.head("extern");
                 self.word_nbsp(abi.to_string());
                 self.bopen(ib);
-                for item in items {
-                    self.ann.nested(self, Nested::ForeignItem(item.id));
+                for &foreign_item in items {
+                    self.ann.nested(self, Nested::ForeignItem(foreign_item));
                 }
                 self.bclose(item.span, cb);
             }
diff --git a/compiler/rustc_metadata/src/foreign_modules.rs b/compiler/rustc_metadata/src/foreign_modules.rs
@@ -19,7 +19,7 @@ pub(crate) fn collect(tcx: TyCtxt<'_>, LocalCrate: LocalCrate) -> FxIndexMap<Def
         let item = tcx.hir_item(id);
 
         if let hir::ItemKind::ForeignMod { abi, items } = item.kind {
-            let foreign_items = items.iter().map(|it| it.id.owner_id.to_def_id()).collect();
+            let foreign_items = items.iter().map(|it| it.owner_id.to_def_id()).collect();
             modules.insert(def_id, ForeignModule { def_id, abi, foreign_items });
         }
     }
diff --git a/compiler/rustc_passes/src/input_stats.rs b/compiler/rustc_passes/src/input_stats.rs
@@ -480,9 +480,9 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
         hir_visit::walk_impl_item(self, ii)
     }
 
-    fn visit_foreign_item_ref(&mut self, fi: &'v hir::ForeignItemRef) {
-        self.record("ForeignItemRef", Some(fi.id.hir_id()), fi);
-        hir_visit::walk_foreign_item_ref(self, fi)
+    fn visit_foreign_item_ref(&mut self, fi: &'v hir::ForeignItemId) {
+        self.record("ForeignItemId", Some(fi.hir_id()), fi);
+        hir_visit::walk_foreign_item_ref(self, *fi)
     }
 
     fn visit_impl_item_ref(&mut self, ii: &'v hir::ImplItemRef) {
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
@@ -755,8 +755,8 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             }
             hir::ItemKind::ForeignMod { items, .. } => {
                 for foreign_item in items {
-                    if let Some(foreign_item_ev) = self.get(foreign_item.id.owner_id.def_id) {
-                        self.reach(foreign_item.id.owner_id.def_id, foreign_item_ev)
+                    if let Some(foreign_item_ev) = self.get(foreign_item.owner_id.def_id) {
+                        self.reach(foreign_item.owner_id.def_id, foreign_item_ev)
                             .generics()
                             .predicates()
                             .ty();
@@ -1658,8 +1658,8 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'_, 'tcx> {
             DefKind::ForeignMod => {
                 let item = tcx.hir_item(id);
                 if let hir::ItemKind::ForeignMod { items, .. } = item.kind {
-                    for foreign_item in items {
-                        let foreign_item = tcx.hir_foreign_item(foreign_item.id);
+                    for &foreign_item in items {
+                        let foreign_item = tcx.hir_foreign_item(foreign_item);
 
                         let ev = self.get(foreign_item.owner_id.def_id);
                         let vis = tcx.local_visibility(foreign_item.owner_id.def_id);
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
@@ -439,8 +439,8 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
 
         match item.kind {
             hir::ItemKind::ForeignMod { items, .. } => {
-                for item in items {
-                    let item = tcx.hir_foreign_item(item.id);
+                for &item in items {
+                    let item = tcx.hir_foreign_item(item);
                     self.visit_foreign_item_inner(item, None, None);
                 }
             }
diff --git a/tests/ui/stats/input-stats.stderr b/tests/ui/stats/input-stats.stderr
@@ -117,7 +117,7 @@ hir-stats ImplItemRef               48 (NN.N%)             2            24
 hir-stats ExprField                 40 (NN.N%)             1            40
 hir-stats Mod                       32 (NN.N%)             1            32
 hir-stats Lifetime                  28 (NN.N%)             1            28
-hir-stats ForeignItemRef            24 (NN.N%)             1            24
+hir-stats ForeignItemId              4 (NN.N%)             1             4
 hir-stats ----------------------------------------------------------------
-hir-stats Total                  8_684                   173
+hir-stats Total                  8_664                   173
 hir-stats ================================================================

Original file line number	Diff line number	Diff line change
`@@ -397,12 +397,8 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {`
`397`	`397`	`self.visit_nested_impl_item(id);`
`398`	`398`	`}`
`399`	`399`
`400`		`- fn visit_foreign_item_ref(&mut self, fi: &'hir ForeignItemRef) {`
`401`		`- // Do not visit the duplicate information in ForeignItemRef. We want to`
`402`		`- // map the actual nodes, not the duplicate ones in the *Ref.`
`403`		`- let ForeignItemRef { id, ident: _, span: _ } = *fi;`
`404`		`-`
`405`		`- self.visit_nested_foreign_item(id);`
	`400`	`+ fn visit_foreign_item_ref(&mut self, id: &'hir ForeignItemId) {`
	`401`	`+ self.visit_nested_foreign_item(*id);`
`406`	`402`	`}`
`407`	`403`
`408`	`404`	`fn visit_where_predicate(&mut self, predicate: &'hir WherePredicate<'hir>) {`
Original file line number	Diff line number	Diff line change
`@@ -441,8 +441,8 @@ pub trait Visitor<'v>: Sized {`
`441`	`441`	`fn visit_impl_item(&mut self, ii: &'v ImplItem<'v>) -> Self::Result {`
`442`	`442`	`walk_impl_item(self, ii)`
`443`	`443`	`}`
`444`		`- fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemRef) -> Self::Result {`
`445`		`- walk_foreign_item_ref(self, ii)`
	`444`	`+ fn visit_foreign_item_ref(&mut self, ii: &'v ForeignItemId) -> Self::Result {`
	`445`	`+ walk_foreign_item_ref(self, *ii)`
`446`	`446`	`}`
`447`	`447`	`fn visit_impl_item_ref(&mut self, ii: &'v ImplItemRef) -> Self::Result {`
`448`	`448`	`walk_impl_item_ref(self, ii)`
`@@ -1290,13 +1290,8 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(`
`1290`	`1290`	`}`
`1291`	`1291`	`}`
`1292`	`1292`
`1293`		`-pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(`
`1294`		`- visitor: &mut V,`
`1295`		`- foreign_item_ref: &'v ForeignItemRef,`
`1296`		`-) -> V::Result {`
`1297`		`- let ForeignItemRef { id, ident, span: _ } = *foreign_item_ref;`
`1298`		`- try_visit!(visitor.visit_nested_foreign_item(id));`
`1299`		`- visitor.visit_ident(ident)`
	`1293`	`+pub fn walk_foreign_item_ref<'v, V: Visitor<'v>>(visitor: &mut V, id: ForeignItemId) -> V::Result {`
	`1294`	`+ visitor.visit_nested_foreign_item(id)`
`1300`	`1295`	`}`
`1301`	`1296`
`1302`	`1297`	`pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(`
Original file line number	Diff line number	Diff line change
`@@ -654,8 +654,8 @@ impl<'a> State<'a> {`
`654`	`654`	`let (cb, ib) = self.head("extern");`
`655`	`655`	`self.word_nbsp(abi.to_string());`
`656`	`656`	`self.bopen(ib);`
`657`		`- for item in items {`
`658`		`- self.ann.nested(self, Nested::ForeignItem(item.id));`
	`657`	`+ for &foreign_item in items {`
	`658`	`+ self.ann.nested(self, Nested::ForeignItem(foreign_item));`
`659`	`659`	`}`
`660`	`660`	`self.bclose(item.span, cb);`
`661`	`661`	`}`
Original file line number	Diff line number	Diff line change
`@@ -19,7 +19,7 @@ pub(crate) fn collect(tcx: TyCtxt<'_>, LocalCrate: LocalCrate) -> FxIndexMap<Def`
`19`	`19`	`let item = tcx.hir_item(id);`
`20`	`20`
`21`	`21`	`if let hir::ItemKind::ForeignMod { abi, items } = item.kind {`
`22`		`- let foreign_items = items.iter().map(\|it\| it.id.owner_id.to_def_id()).collect();`
	`22`	`+ let foreign_items = items.iter().map(\|it\| it.owner_id.to_def_id()).collect();`
`23`	`23`	`modules.insert(def_id, ForeignModule { def_id, abi, foreign_items });`
`24`	`24`	`}`
`25`	`25`	`}`
Original file line number	Diff line number	Diff line change
`@@ -480,9 +480,9 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {`
`480`	`480`	`hir_visit::walk_impl_item(self, ii)`
`481`	`481`	`}`
`482`	`482`
`483`		`- fn visit_foreign_item_ref(&mut self, fi: &'v hir::ForeignItemRef) {`
`484`		`- self.record("ForeignItemRef", Some(fi.id.hir_id()), fi);`
`485`		`- hir_visit::walk_foreign_item_ref(self, fi)`
	`483`	`+ fn visit_foreign_item_ref(&mut self, fi: &'v hir::ForeignItemId) {`
	`484`	`+ self.record("ForeignItemId", Some(fi.hir_id()), fi);`
	`485`	`+ hir_visit::walk_foreign_item_ref(self, *fi)`
`486`	`486`	`}`
`487`	`487`
`488`	`488`	`fn visit_impl_item_ref(&mut self, ii: &'v hir::ImplItemRef) {`
Original file line number	Diff line number	Diff line change
`@@ -439,8 +439,8 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {`
`439`	`439`
`440`	`440`	`match item.kind {`
`441`	`441`	`hir::ItemKind::ForeignMod { items, .. } => {`
`442`		`- for item in items {`
`443`		`- let item = tcx.hir_foreign_item(item.id);`
	`442`	`+ for &item in items {`
	`443`	`+ let item = tcx.hir_foreign_item(item);`
`444`	`444`	`self.visit_foreign_item_inner(item, None, None);`
`445`	`445`	`}`
`446`	`446`	`}`