Add a helper for building an owner id in ast lowering

Author: oli-obk

Diff for: compiler/rustc_ast_lowering/src/item.rs

@@ -132,8 +132,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     pub(super) fn lower_item_ref(&mut self, i: &Item) -> SmallVec<[hir::ItemId; 1]> {
-        let mut node_ids =
-            smallvec![hir::ItemId { owner_id: hir::OwnerId { def_id: self.local_def_id(i.id) } }];
+        let mut node_ids = smallvec![hir::ItemId { owner_id: self.owner_id(i.id) }];
         if let ItemKind::Use(use_tree) = &i.kind {
             self.lower_item_id_use_tree(use_tree, &mut node_ids);
         }
@@ -144,9 +143,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         match &tree.kind {
             UseTreeKind::Nested { items, .. } => {
                 for &(ref nested, id) in items {
-                    vec.push(hir::ItemId {
-                        owner_id: hir::OwnerId { def_id: self.local_def_id(id) },
-                    });
+                    vec.push(hir::ItemId { owner_id: self.owner_id(id) });
                     self.lower_item_id_use_tree(nested, vec);
                 }
             }
@@ -585,7 +582,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
                 // Add all the nested `PathListItem`s to the HIR.
                 for &(ref use_tree, id) in trees {
-                    let new_hir_id = self.local_def_id(id);
+                    let owner_id = self.owner_id(id);
 
                     // Each `use` import is an item and thus are owners of the
                     // names in the path. Up to this point the nested import is
@@ -602,7 +599,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         }
 
                         let item = hir::Item {
-                            owner_id: hir::OwnerId { def_id: new_hir_id },
+                            owner_id,
                             kind,
                             vis_span,
                             span: this.lower_span(use_tree.span),
@@ -710,7 +707,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_foreign_item_ref(&mut self, i: &ForeignItem) -> hir::ForeignItemRef {
         hir::ForeignItemRef {
-            id: hir::ForeignItemId { owner_id: hir::OwnerId { def_id: self.local_def_id(i.id) } },
+            id: hir::ForeignItemId { owner_id: self.owner_id(i.id) },
             ident: self.lower_ident(i.ident),
             span: self.lower_span(i.span),
         }
@@ -931,7 +928,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 panic!("macros should have been expanded by now")
             }
         };
-        let id = hir::TraitItemId { owner_id: hir::OwnerId { def_id: self.local_def_id(i.id) } };
+        let id = hir::TraitItemId { owner_id: self.owner_id(i.id) };
         hir::TraitItemRef {
             id,
             ident: self.lower_ident(i.ident),
@@ -1046,7 +1043,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
     fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemRef {
         hir::ImplItemRef {
-            id: hir::ImplItemId { owner_id: hir::OwnerId { def_id: self.local_def_id(i.id) } },
+            id: hir::ImplItemId { owner_id: self.owner_id(i.id) },
             ident: self.lower_ident(i.ident),
             span: self.lower_span(i.span),
             kind: match &i.kind {

Diff for: compiler/rustc_ast_lowering/src/lib.rs

@@ -536,6 +536,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{node:?}`"))
     }
 
+    /// Given the id of an owner node in the AST, returns the corresponding `OwnerId`.
+    fn owner_id(&self, node: NodeId) -> hir::OwnerId {
+        hir::OwnerId { def_id: self.local_def_id(node) }
+    }
+
     /// Freshen the `LoweringContext` and ready it to lower a nested item.
     /// The lowered item is registered into `self.children`.
     ///
@@ -547,7 +552,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         owner: NodeId,
         f: impl FnOnce(&mut Self) -> hir::OwnerNode<'hir>,
     ) {
-        let def_id = self.local_def_id(owner);
+        let owner_id = self.owner_id(owner);
 
         let current_attrs = std::mem::take(&mut self.attrs);
         let current_bodies = std::mem::take(&mut self.bodies);
@@ -558,8 +563,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         #[cfg(debug_assertions)]
         let current_node_id_to_local_id = std::mem::take(&mut self.node_id_to_local_id);
         let current_trait_map = std::mem::take(&mut self.trait_map);
-        let current_owner =
-            std::mem::replace(&mut self.current_hir_id_owner, hir::OwnerId { def_id });
+        let current_owner = std::mem::replace(&mut self.current_hir_id_owner, owner_id);
         let current_local_counter =
             std::mem::replace(&mut self.item_local_id_counter, hir::ItemLocalId::new(1));
         let current_impl_trait_defs = std::mem::take(&mut self.impl_trait_defs);
@@ -577,7 +581,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
 
         let item = f(self);
-        debug_assert_eq!(def_id, item.def_id().def_id);
+        debug_assert_eq!(owner_id, item.def_id());
         // `f` should have consumed all the elements in these vectors when constructing `item`.
         debug_assert!(self.impl_trait_defs.is_empty());
         debug_assert!(self.impl_trait_bounds.is_empty());
@@ -598,8 +602,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.impl_trait_defs = current_impl_trait_defs;
         self.impl_trait_bounds = current_impl_trait_bounds;
 
-        debug_assert!(!self.children.iter().any(|(id, _)| id == &def_id));
-        self.children.push((def_id, hir::MaybeOwner::Owner(info)));
+        debug_assert!(!self.children.iter().any(|(id, _)| id == &owner_id.def_id));
+        self.children.push((owner_id.def_id, hir::MaybeOwner::Owner(info)));
     }
 
     fn make_owner_info(&mut self, node: hir::OwnerNode<'hir>) -> &'hir hir::OwnerInfo<'hir> {