Move trait_item_def_id from ImplItemRef to ImplItem.

cjgillot · cjgillot · commit 3ecd03bdfd8d · 2025-07-13T13:50:00.000Z
diff --git a/compiler/rustc_ast_lowering/src/index.rs b/compiler/rustc_ast_lowering/src/index.rs
@@ -392,7 +392,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
     fn visit_impl_item_ref(&mut self, ii: &'hir ImplItemRef) {
         // Do not visit the duplicate information in ImplItemRef. We want to
         // map the actual nodes, not the duplicate ones in the *Ref.
-        let ImplItemRef { id, ident: _, kind: _, span: _, trait_item_def_id: _ } = *ii;
+        let ImplItemRef { id, ident: _, kind: _, span: _ } = *ii;
 
         self.visit_nested_impl_item(id);
     }
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
@@ -1128,6 +1128,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
             span: self.lower_span(i.span),
             defaultness,
             has_delayed_lints: !self.delayed_lints.is_empty(),
+            trait_item_def_id: self
+                .resolver
+                .get_partial_res(i.id)
+                .map(|r| r.expect_full_res().opt_def_id())
+                .unwrap_or(None),
         };
         self.arena.alloc(item)
     }
@@ -1157,11 +1162,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     panic!("macros should have been expanded by now")
                 }
             },
-            trait_item_def_id: self
-                .resolver
-                .get_partial_res(i.id)
-                .map(|r| r.expect_full_res().opt_def_id())
-                .unwrap_or(None),
         }
     }
 
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
@@ -3172,6 +3172,8 @@ pub struct ImplItem<'hir> {
     pub span: Span,
     pub vis_span: Span,
     pub has_delayed_lints: bool,
+    /// When we are in a trait impl, link to the trait-item's id.
+    pub trait_item_def_id: Option<DefId>,
 }
 
 impl<'hir> ImplItem<'hir> {
@@ -4429,8 +4431,6 @@ pub struct ImplItemRef {
     pub ident: Ident,
     pub kind: AssocItemKind,
     pub span: Span,
-    /// When we are in a trait impl, link to the trait-item's id.
-    pub trait_item_def_id: Option<DefId>,
 }
 
 #[derive(Copy, Clone, PartialEq, Debug, HashStable_Generic)]
@@ -4969,7 +4969,7 @@ mod size_asserts {
     static_assert_size!(GenericBound<'_>, 64);
     static_assert_size!(Generics<'_>, 56);
     static_assert_size!(Impl<'_>, 80);
-    static_assert_size!(ImplItem<'_>, 88);
+    static_assert_size!(ImplItem<'_>, 96);
     static_assert_size!(ImplItemKind<'_>, 40);
     static_assert_size!(Item<'_>, 88);
     static_assert_size!(ItemKind<'_>, 64);
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
@@ -1271,6 +1271,7 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(
         span: _,
         vis_span: _,
         has_delayed_lints: _,
+        trait_item_def_id: _,
     } = *impl_item;
 
     try_visit!(visitor.visit_ident(ident));
@@ -1306,7 +1307,7 @@ pub fn walk_impl_item_ref<'v, V: Visitor<'v>>(
     visitor: &mut V,
     impl_item_ref: &'v ImplItemRef,
 ) -> V::Result {
-    let ImplItemRef { id, ident, ref kind, span: _, trait_item_def_id: _ } = *impl_item_ref;
+    let ImplItemRef { id, ident, ref kind, span: _ } = *impl_item_ref;
     try_visit!(visitor.visit_nested_impl_item(id));
     try_visit!(visitor.visit_ident(ident));
     visitor.visit_associated_item_kind(kind)
diff --git a/compiler/rustc_ty_utils/src/assoc.rs b/compiler/rustc_ty_utils/src/assoc.rs
@@ -6,6 +6,8 @@ use rustc_hir::{self as hir, ItemKind};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, ImplTraitInTraitData, TyCtxt};
 use rustc_middle::{bug, span_bug};
+use rustc_span::Ident;
+use rustc_span::symbol::kw;
 
 pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers {
@@ -66,46 +68,33 @@ fn impl_item_implementor_ids(tcx: TyCtxt<'_>, impl_id: DefId) -> DefIdMap<DefId>
 }
 
 fn associated_item(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::AssocItem {
-    let id = tcx.local_def_id_to_hir_id(def_id);
-    let parent_def_id = tcx.hir_get_parent_item(id);
-    let parent_item = tcx.hir_expect_item(parent_def_id.def_id);
-    match parent_item.kind {
-        hir::ItemKind::Impl(impl_) => {
-            if let Some(impl_item_ref) = impl_.items.iter().find(|i| i.id.owner_id.def_id == def_id)
-            {
-                let assoc_item = associated_item_from_impl_item_ref(impl_item_ref);
-                debug_assert_eq!(assoc_item.def_id.expect_local(), def_id);
-                return assoc_item;
-            }
-        }
-
-        hir::ItemKind::Trait(.., trait_item_refs) => {
-            if let Some(trait_item_ref) =
-                trait_item_refs.iter().find(|i| i.id.owner_id.def_id == def_id)
-            {
-                let assoc_item = associated_item_from_trait_item_ref(trait_item_ref);
-                debug_assert_eq!(assoc_item.def_id.expect_local(), def_id);
-                return assoc_item;
-            }
-        }
-
-        _ => {}
-    }
+    let assoc_item = match tcx.hir_node_by_def_id(def_id) {
+        hir::Node::TraitItem(ti) => associated_item_from_trait_item(tcx, ti),
+        hir::Node::ImplItem(ii) => associated_item_from_impl_item(tcx, ii),
+        node => span_bug!(tcx.def_span(def_id), "impl item or item not found: {:?}", node,),
+    };
+    debug_assert_eq!(assoc_item.def_id.expect_local(), def_id);
+    assoc_item
+}
 
-    span_bug!(
-        parent_item.span,
-        "unexpected parent of trait or impl item or item not found: {:?}",
-        parent_item.kind
-    )
+fn fn_has_self_parameter(tcx: TyCtxt<'_>, owner_id: hir::OwnerId) -> bool {
+    matches!(tcx.fn_arg_idents(owner_id.def_id), [Some(Ident { name: kw::SelfLower, .. }), ..])
 }
 
-fn associated_item_from_trait_item_ref(trait_item_ref: &hir::TraitItemRef) -> ty::AssocItem {
-    let owner_id = trait_item_ref.id.owner_id;
-    let name = trait_item_ref.ident.name;
-    let kind = match trait_item_ref.kind {
-        hir::AssocItemKind::Const => ty::AssocKind::Const { name },
-        hir::AssocItemKind::Fn { has_self } => ty::AssocKind::Fn { name, has_self },
-        hir::AssocItemKind::Type => ty::AssocKind::Type { data: ty::AssocTypeData::Normal(name) },
+fn associated_item_from_trait_item(
+    tcx: TyCtxt<'_>,
+    trait_item: &hir::TraitItem<'_>,
+) -> ty::AssocItem {
+    let owner_id = trait_item.owner_id;
+    let name = trait_item.ident.name;
+    let kind = match trait_item.kind {
+        hir::TraitItemKind::Const { .. } => ty::AssocKind::Const { name },
+        hir::TraitItemKind::Fn { .. } => {
+            ty::AssocKind::Fn { name, has_self: fn_has_self_parameter(tcx, owner_id) }
+        }
+        hir::TraitItemKind::Type { .. } => {
+            ty::AssocKind::Type { data: ty::AssocTypeData::Normal(name) }
+        }
     };
 
     ty::AssocItem {
@@ -116,19 +105,23 @@ fn associated_item_from_trait_item_ref(trait_item_ref: &hir::TraitItemRef) -> ty
     }
 }
 
-fn associated_item_from_impl_item_ref(impl_item_ref: &hir::ImplItemRef) -> ty::AssocItem {
-    let def_id = impl_item_ref.id.owner_id;
-    let name = impl_item_ref.ident.name;
-    let kind = match impl_item_ref.kind {
-        hir::AssocItemKind::Const => ty::AssocKind::Const { name },
-        hir::AssocItemKind::Fn { has_self } => ty::AssocKind::Fn { name, has_self },
-        hir::AssocItemKind::Type => ty::AssocKind::Type { data: ty::AssocTypeData::Normal(name) },
+fn associated_item_from_impl_item(tcx: TyCtxt<'_>, impl_item: &hir::ImplItem<'_>) -> ty::AssocItem {
+    let owner_id = impl_item.owner_id;
+    let name = impl_item.ident.name;
+    let kind = match impl_item.kind {
+        hir::ImplItemKind::Const { .. } => ty::AssocKind::Const { name },
+        hir::ImplItemKind::Fn { .. } => {
+            ty::AssocKind::Fn { name, has_self: fn_has_self_parameter(tcx, owner_id) }
+        }
+        hir::ImplItemKind::Type { .. } => {
+            ty::AssocKind::Type { data: ty::AssocTypeData::Normal(name) }
+        }
     };
 
     ty::AssocItem {
         kind,
-        def_id: def_id.to_def_id(),
-        trait_item_def_id: impl_item_ref.trait_item_def_id,
+        def_id: owner_id.to_def_id(),
+        trait_item_def_id: impl_item.trait_item_def_id,
         container: ty::AssocItemContainer::Impl,
     }
 }
@@ -196,17 +189,13 @@ fn associated_types_for_impl_traits_in_trait_or_impl<'tcx>(
                         return None;
                     }
                     let did = item.id.owner_id.def_id.to_def_id();
+                    let item = tcx.hir_impl_item(item.id);
                     let Some(trait_item_def_id) = item.trait_item_def_id else {
                         return Some((did, vec![]));
                     };
                     let iter = in_trait_def[&trait_item_def_id].iter().map(|&id| {
-                        associated_type_for_impl_trait_in_impl(
-                            tcx,
-                            id,
-                            item.id.owner_id.def_id,
-                            disambiguator,
-                        )
-                        .to_def_id()
+                        associated_type_for_impl_trait_in_impl(tcx, id, item, disambiguator)
+                            .to_def_id()
                     });
                     Some((did, iter.collect()))
                 })
@@ -285,20 +274,20 @@ fn associated_type_for_impl_trait_in_trait(
 
 /// Given an `trait_assoc_def_id` corresponding to an associated item synthesized
 /// from an `impl Trait` in an associated function from a trait, and an
-/// `impl_fn_def_id` that represents an implementation of the associated function
+/// `impl_fn` that represents an implementation of the associated function
 /// that the `impl Trait` comes from, synthesize an associated type for that `impl Trait`
 /// that inherits properties that we infer from the method and the associated type.
 fn associated_type_for_impl_trait_in_impl(
     tcx: TyCtxt<'_>,
     trait_assoc_def_id: DefId,
-    impl_fn_def_id: LocalDefId,
+    impl_fn: &hir::ImplItem<'_>,
     disambiguator: &mut DisambiguatorState,
 ) -> LocalDefId {
-    let impl_local_def_id = tcx.local_parent(impl_fn_def_id);
+    let impl_local_def_id = tcx.local_parent(impl_fn.owner_id.def_id);
 
-    let decl = tcx.hir_node_by_def_id(impl_fn_def_id).fn_decl().expect("expected decl");
-    let span = match decl.output {
-        hir::FnRetTy::DefaultReturn(_) => tcx.def_span(impl_fn_def_id),
+    let hir::ImplItemKind::Fn(fn_sig, _) = impl_fn.kind else { bug!("expected decl") };
+    let span = match fn_sig.decl.output {
+        hir::FnRetTy::DefaultReturn(_) => tcx.def_span(impl_fn.owner_id),
         hir::FnRetTy::Return(ty) => ty.span,
     };
 
@@ -329,7 +318,7 @@ fn associated_type_for_impl_trait_in_impl(
     impl_assoc_ty.associated_item(ty::AssocItem {
         kind: ty::AssocKind::Type {
             data: ty::AssocTypeData::Rpitit(ImplTraitInTraitData::Impl {
-                fn_def_id: impl_fn_def_id.to_def_id(),
+                fn_def_id: impl_fn.owner_id.to_def_id(),
             }),
         },
         def_id,
@@ -338,10 +327,10 @@ fn associated_type_for_impl_trait_in_impl(
     });
 
     // Copy visility of the containing function.
-    impl_assoc_ty.visibility(tcx.visibility(impl_fn_def_id));
+    impl_assoc_ty.visibility(tcx.visibility(impl_fn.owner_id));
 
     // Copy defaultness of the containing function.
-    impl_assoc_ty.defaultness(tcx.defaultness(impl_fn_def_id));
+    impl_assoc_ty.defaultness(tcx.defaultness(impl_fn.owner_id));
 
     // Copy generics_of the trait's associated item but the impl as the parent.
     // FIXME: This may be detrimental to diagnostics, as we resolve the early-bound vars
diff --git a/tests/ui/stats/input-stats.stderr b/tests/ui/stats/input-stats.stderr
@@ -107,17 +107,17 @@ hir-stats WherePredicate            72 (NN.N%)             3            24
 hir-stats - BoundPredicate            72 (NN.N%)             3
 hir-stats Local                     72 (NN.N%)             1            72
 hir-stats InlineAsm                 72 (NN.N%)             1            72
-hir-stats ImplItemRef               72 (NN.N%)             2            36
 hir-stats Body                      72 (NN.N%)             3            24
 hir-stats Param                     64 (NN.N%)             2            32
 hir-stats GenericArg                64 (NN.N%)             4            16
 hir-stats - Type                      16 (NN.N%)             1
 hir-stats - Lifetime                  48 (NN.N%)             3
 hir-stats TraitItemRef              56 (NN.N%)             2            28
+hir-stats ImplItemRef               56 (NN.N%)             2            28
 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 ----------------------------------------------------------------
-hir-stats Total                  8_716                   173
+hir-stats Total                  8_700                   173
 hir-stats ================================================================

Original file line number	Diff line number	Diff line change
`@@ -392,7 +392,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {`
`392`	`392`	`fn visit_impl_item_ref(&mut self, ii: &'hir ImplItemRef) {`
`393`	`393`	`// Do not visit the duplicate information in ImplItemRef. We want to`
`394`	`394`	`// map the actual nodes, not the duplicate ones in the *Ref.`
`395`		`- let ImplItemRef { id, ident: _, kind: _, span: _, trait_item_def_id: _ } = *ii;`
	`395`	`+ let ImplItemRef { id, ident: _, kind: _, span: _ } = *ii;`
`396`	`396`
`397`	`397`	`self.visit_nested_impl_item(id);`
`398`	`398`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1128,6 +1128,11 @@ impl<'hir> LoweringContext<'_, 'hir> {`
`1128`	`1128`	`span: self.lower_span(i.span),`
`1129`	`1129`	`defaultness,`
`1130`	`1130`	`has_delayed_lints: !self.delayed_lints.is_empty(),`
	`1131`	`+ trait_item_def_id: self`
	`1132`	`+ .resolver`
	`1133`	`+ .get_partial_res(i.id)`
	`1134`	`+ .map(\|r\| r.expect_full_res().opt_def_id())`
	`1135`	`+ .unwrap_or(None),`
`1131`	`1136`	`};`
`1132`	`1137`	`self.arena.alloc(item)`
`1133`	`1138`	`}`
`@@ -1157,11 +1162,6 @@ impl<'hir> LoweringContext<'_, 'hir> {`
`1157`	`1162`	`panic!("macros should have been expanded by now")`
`1158`	`1163`	`}`
`1159`	`1164`	`},`
`1160`		`- trait_item_def_id: self`
`1161`		`- .resolver`
`1162`		`- .get_partial_res(i.id)`
`1163`		`- .map(\|r\| r.expect_full_res().opt_def_id())`
`1164`		`- .unwrap_or(None),`
`1165`	`1165`	`}`
`1166`	`1166`	`}`
`1167`	`1167`