Introduce hir::ImplItemImplKind

Author: camsteffen

compiler/rustc_ast_lowering/src/item.rs

@@ -6,7 +6,7 @@ use rustc_errors::{E0570, ErrorGuaranteed, struct_span_code_err};
 use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, PerNS, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LocalDefId};
-use rustc_hir::{self as hir, HirId, LifetimeSource, PredicateOrigin, find_attr};
+use rustc_hir::{self as hir, HirId, ImplItemImplKind, LifetimeSource, PredicateOrigin, find_attr};
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::span_bug;
 use rustc_middle::ty::{ResolverAstLowering, TyCtxt};
@@ -1101,16 +1101,21 @@ impl<'hir> LoweringContext<'_, 'hir> {
             owner_id: hir_id.expect_owner(),
             ident: self.lower_ident(ident),
             generics,
+            impl_kind: if is_in_trait_impl {
+                ImplItemImplKind::Trait {
+                    defaultness,
+                    trait_item_def_id: self
+                        .resolver
+                        .get_partial_res(i.id)
+                        .map(|r| r.expect_full_res().opt_def_id())
+                        .unwrap_or(None),
+                }
+            } else {
+                ImplItemImplKind::Inherent { vis_span: self.lower_span(i.vis.span) }
+            },
             kind,
-            vis_span: self.lower_span(i.vis.span),
             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)
     }

compiler/rustc_hir/src/hir.rs

@@ -3190,12 +3190,22 @@ pub struct ImplItem<'hir> {
     pub owner_id: OwnerId,
     pub generics: &'hir Generics<'hir>,
     pub kind: ImplItemKind<'hir>,
-    pub defaultness: Defaultness,
+    pub impl_kind: ImplItemImplKind,
     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>,
+}
+
+#[derive(Debug, Clone, Copy, HashStable_Generic)]
+pub enum ImplItemImplKind {
+    Inherent {
+        vis_span: Span,
+    },
+    Trait {
+        defaultness: Defaultness,
+        /// Item in the trait that this item implements.
+        /// May be `None` if there is an error.
+        trait_item_def_id: Option<DefId>,
+    },
 }
 
 impl<'hir> ImplItem<'hir> {
@@ -3209,6 +3219,13 @@ impl<'hir> ImplItem<'hir> {
         ImplItemId { owner_id: self.owner_id }
     }
 
+    pub fn vis_span(&self) -> Option<Span> {
+        match self.impl_kind {
+            ImplItemImplKind::Trait { .. } => None,
+            ImplItemImplKind::Inherent { vis_span, .. } => Some(vis_span),
+        }
+    }
+
     expect_methods_self_kind! {
         expect_const, (&'hir Ty<'hir>, BodyId), ImplItemKind::Const(ty, body), (ty, *body);
         expect_fn,    (&FnSig<'hir>, BodyId),   ImplItemKind::Fn(ty, body),    (ty, *body);
@@ -4953,7 +4970,7 @@ mod size_asserts {
     static_assert_size!(GenericBound<'_>, 64);
     static_assert_size!(Generics<'_>, 56);
     static_assert_size!(Impl<'_>, 80);
-    static_assert_size!(ImplItem<'_>, 96);
+    static_assert_size!(ImplItem<'_>, 88);
     static_assert_size!(ImplItemKind<'_>, 40);
     static_assert_size!(Item<'_>, 88);
     static_assert_size!(ItemKind<'_>, 64);

compiler/rustc_hir/src/intravisit.rs

@@ -1257,18 +1257,21 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(
         owner_id: _,
         ident,
         ref generics,
+        ref impl_kind,
         ref kind,
-        ref defaultness,
         span: _,
-        vis_span: _,
         has_delayed_lints: _,
-        trait_item_def_id: _,
     } = *impl_item;
 
     try_visit!(visitor.visit_ident(ident));
     try_visit!(visitor.visit_generics(generics));
-    try_visit!(visitor.visit_defaultness(defaultness));
     try_visit!(visitor.visit_id(impl_item.hir_id()));
+    match impl_kind {
+        ImplItemImplKind::Inherent { vis_span: _ } => {}
+        ImplItemImplKind::Trait { defaultness, trait_item_def_id: _ } => {
+            try_visit!(visitor.visit_defaultness(defaultness));
+        }
+    }
     match *kind {
         ImplItemKind::Const(ref ty, body) => {
             try_visit!(visitor.visit_ty_unambig(ty));

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -198,7 +198,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
                 }
             }
             ImplItemKind::Type(ty) => {
-                if tcx.impl_trait_ref(tcx.hir_get_parent_item(hir_id)).is_none() {
+                if let ImplItemImplKind::Inherent { .. } = item.impl_kind {
                     check_feature_inherent_assoc_ty(tcx, item.span);
                 }
 

compiler/rustc_lint/src/builtin.rs

@@ -28,7 +28,7 @@ use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId, LocalDefId};
 use rustc_hir::intravisit::FnKind as HirFnKind;
-use rustc_hir::{Body, FnDecl, PatKind, PredicateOrigin, find_attr};
+use rustc_hir::{Body, FnDecl, ImplItemImplKind, PatKind, PredicateOrigin, find_attr};
 use rustc_middle::bug;
 use rustc_middle::lint::LevelAndSource;
 use rustc_middle::ty::layout::LayoutOf;
@@ -1310,9 +1310,8 @@ impl<'tcx> LateLintPass<'tcx> for UnreachablePub {
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) {
-        // Only lint inherent impl items.
-        if cx.tcx.associated_item(impl_item.owner_id).trait_item_def_id.is_none() {
-            self.perform_lint(cx, "item", impl_item.owner_id.def_id, impl_item.vis_span, false);
+        if let ImplItemImplKind::Inherent { vis_span } = impl_item.impl_kind {
+            self.perform_lint(cx, "item", impl_item.owner_id.def_id, vis_span, false);
         }
     }
 }

compiler/rustc_middle/src/ty/context.rs

@@ -2206,7 +2206,16 @@ impl<'tcx> TyCtxt<'tcx> {
 
         let is_impl_item = match self.hir_node_by_def_id(suitable_region_binding_scope) {
             Node::Item(..) | Node::TraitItem(..) => false,
-            Node::ImplItem(..) => self.is_bound_region_in_impl_item(suitable_region_binding_scope),
+            Node::ImplItem(impl_item) => match impl_item.impl_kind {
+                // For now, we do not try to target impls of traits. This is
+                // because this message is going to suggest that the user
+                // change the fn signature, but they may not be free to do so,
+                // since the signature must match the trait.
+                //
+                // FIXME(#42706) -- in some cases, we could do better here.
+                hir::ImplItemImplKind::Trait { .. } => true,
+                _ => false,
+            },
             _ => false,
         };
 
@@ -2260,21 +2269,6 @@ impl<'tcx> TyCtxt<'tcx> {
         None
     }
 
-    /// Checks if the bound region is in Impl Item.
-    pub fn is_bound_region_in_impl_item(self, suitable_region_binding_scope: LocalDefId) -> bool {
-        let container_id = self.parent(suitable_region_binding_scope.to_def_id());
-        if self.impl_trait_ref(container_id).is_some() {
-            // For now, we do not try to target impls of traits. This is
-            // because this message is going to suggest that the user
-            // change the fn signature, but they may not be free to do so,
-            // since the signature must match the trait.
-            //
-            // FIXME(#42706) -- in some cases, we could do better here.
-            return true;
-        }
-        false
-    }
-
     /// Determines whether identifiers in the assembly have strict naming rules.
     /// Currently, only NVPTX* targets need it.
     pub fn has_strict_asm_symbol_naming(self) -> bool {

compiler/rustc_passes/src/dead.rs

@@ -372,31 +372,27 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
     /// Automatically generated items marked with `rustc_trivial_field_reads`
     /// will be ignored for the purposes of dead code analysis (see PR #85200
     /// for discussion).
-    fn should_ignore_item(&mut self, def_id: DefId) -> bool {
-        if let Some(impl_of) = self.tcx.impl_of_assoc(def_id) {
-            if !self.tcx.is_automatically_derived(impl_of) {
-                return false;
-            }
-
-            if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of)
-                && self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads)
+    fn should_ignore_impl_item(&mut self, impl_item: &hir::ImplItem<'_>) -> bool {
+        if let hir::ImplItemImplKind::Trait { .. } = impl_item.impl_kind
+            && let impl_of = self.tcx.parent(impl_item.owner_id.to_def_id())
+            && self.tcx.is_automatically_derived(impl_of)
+            && let trait_ref = self.tcx.impl_trait_ref(impl_of).unwrap().instantiate_identity()
+            && self.tcx.has_attr(trait_ref.def_id, sym::rustc_trivial_field_reads)
+        {
+            if let ty::Adt(adt_def, _) = trait_ref.self_ty().kind()
+                && let Some(adt_def_id) = adt_def.did().as_local()
             {
-                let trait_ref = self.tcx.impl_trait_ref(impl_of).unwrap().instantiate_identity();
-                if let ty::Adt(adt_def, _) = trait_ref.self_ty().kind()
-                    && let Some(adt_def_id) = adt_def.did().as_local()
-                {
-                    self.ignored_derived_traits.entry(adt_def_id).or_default().insert(trait_of);
-                }
-                return true;
+                self.ignored_derived_traits.entry(adt_def_id).or_default().insert(trait_ref.def_id);
             }
+            return true;
         }
 
         false
     }
 
     fn visit_node(&mut self, node: Node<'tcx>) {
-        if let Node::ImplItem(hir::ImplItem { owner_id, .. }) = node
-            && self.should_ignore_item(owner_id.to_def_id())
+        if let Node::ImplItem(impl_item) = node
+            && self.should_ignore_impl_item(impl_item)
         {
             return;
         }
@@ -438,7 +434,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
             }
             Node::ImplItem(impl_item) => {
                 let item = self.tcx.local_parent(impl_item.owner_id.def_id);
-                if self.tcx.impl_trait_ref(item).is_none() {
+                if let hir::ImplItemImplKind::Inherent { .. } = impl_item.impl_kind {
                     //// If it's a type whose items are live, then it's live, too.
                     //// This is done to handle the case where, for example, the static
                     //// method of a private type is used, but the type itself is never

compiler/rustc_passes/src/stability.rs

@@ -528,8 +528,7 @@ impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> {
 
     fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) {
         self.check_compatible_stability(ii.owner_id.def_id);
-        let impl_def_id = self.tcx.hir_get_parent_item(ii.hir_id());
-        if self.tcx.impl_trait_ref(impl_def_id).is_none() {
+        if let hir::ImplItemImplKind::Inherent { .. } = ii.impl_kind {
             self.check_missing_stability(ii.owner_id.def_id);
             self.check_missing_const_stability(ii.owner_id.def_id);
         }

compiler/rustc_ty_utils/src/assoc.rs

@@ -2,7 +2,7 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatorState};
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{self as hir, ItemKind};
+use rustc_hir::{self as hir, ImplItemImplKind, ItemKind};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, ImplTraitInTraitData, TyCtxt};
 use rustc_middle::{bug, span_bug};
@@ -121,8 +121,11 @@ fn associated_item_from_impl_item(tcx: TyCtxt<'_>, impl_item: &hir::ImplItem<'_>
     ty::AssocItem {
         kind,
         def_id: owner_id.to_def_id(),
-        trait_item_def_id: impl_item.trait_item_def_id,
         container: ty::AssocItemContainer::Impl,
+        trait_item_def_id: match impl_item.impl_kind {
+            ImplItemImplKind::Inherent { .. } => None,
+            ImplItemImplKind::Trait { trait_item_def_id, .. } => trait_item_def_id,
+        },
     }
 }
 struct RPITVisitor<'a, 'tcx> {
@@ -190,7 +193,10 @@ fn associated_types_for_impl_traits_in_trait_or_impl<'tcx>(
                     }
                     let did = item.owner_id.def_id.to_def_id();
                     let item = tcx.hir_impl_item(*item);
-                    let Some(trait_item_def_id) = item.trait_item_def_id else {
+                    let ImplItemImplKind::Trait {
+                        trait_item_def_id: Some(trait_item_def_id), ..
+                    } = item.impl_kind
+                    else {
                         return Some((did, vec![]));
                     };
                     let iter = in_trait_def[&trait_item_def_id].iter().map(|&id| {

compiler/rustc_ty_utils/src/ty.rs

@@ -84,8 +84,15 @@ fn defaultness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Defaultness {
             kind: hir::ItemKind::Impl(hir::Impl { defaultness, of_trait: Some(_), .. }),
             ..
         })
-        | hir::Node::ImplItem(hir::ImplItem { defaultness, .. })
+        | hir::Node::ImplItem(hir::ImplItem {
+            impl_kind: hir::ImplItemImplKind::Trait { defaultness, .. },
+            ..
+        })
         | hir::Node::TraitItem(hir::TraitItem { defaultness, .. }) => *defaultness,
+        hir::Node::ImplItem(hir::ImplItem {
+            impl_kind: hir::ImplItemImplKind::Inherent { .. },
+            ..
+        }) => hir::Defaultness::Final,
         node => {
             bug!("`defaultness` called on {:?}", node);
         }