Intern OpaqueTy on ItemKind::OpaqueTy

compiler/rustc_ast_lowering/src/lib.rs

@@ -1658,7 +1658,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         span: Span,
         opaque_ty_span: Span,
     ) -> hir::OwnerNode<'hir> {
-        let opaque_ty_item_kind = hir::ItemKind::OpaqueTy(opaque_ty_item);
+        let opaque_ty_item_kind = hir::ItemKind::OpaqueTy(self.arena.alloc(opaque_ty_item));
         // Generate an `type Foo = impl Trait;` declaration.
         trace!("registering opaque type with id {:#?}", opaque_ty_id);
         let opaque_ty_item = hir::Item {

compiler/rustc_hir/src/hir.rs

@@ -3315,7 +3315,7 @@ pub enum ItemKind<'hir> {
     /// A type alias, e.g., `type Foo = Bar<u8>`.
     TyAlias(&'hir Ty<'hir>, &'hir Generics<'hir>),
     /// An opaque `impl Trait` type alias, e.g., `type Foo = impl Bar;`.
-    OpaqueTy(OpaqueTy<'hir>),
+    OpaqueTy(&'hir OpaqueTy<'hir>),
     /// An enum definition, e.g., `enum Foo<A, B> {C<A>, D<B>}`.
     Enum(EnumDef<'hir>, &'hir Generics<'hir>),
     /// A struct definition, e.g., `struct Foo<A> {x: A}`.

compiler/rustc_hir/src/intravisit.rs

@@ -502,7 +502,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) {
             visitor.visit_ty(ty);
             visitor.visit_generics(generics)
         }
-        ItemKind::OpaqueTy(OpaqueTy { ref generics, bounds, .. }) => {
+        ItemKind::OpaqueTy(&OpaqueTy { generics, bounds, .. }) => {
             visitor.visit_id(item.hir_id());
             walk_generics(visitor, generics);
             walk_list!(visitor, visit_param_bound, bounds);

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2809,7 +2809,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 let opaque_ty = tcx.hir().item(item_id);
 
                 match opaque_ty.kind {
-                    hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
+                    hir::ItemKind::OpaqueTy(&hir::OpaqueTy { origin, .. }) => {
                         let local_def_id = item_id.owner_id.def_id;
                         // If this is an RPITIT and we are using the new RPITIT lowering scheme, we
                         // generate the def_id of an associated type for the trait and return as

compiler/rustc_hir_analysis/src/check/check.rs

@@ -299,7 +299,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes(
         }
     }
 
-    if let ItemKind::OpaqueTy(hir::OpaqueTy {
+    if let ItemKind::OpaqueTy(&hir::OpaqueTy {
         origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
         in_trait,
         ..

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -144,7 +144,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
             Some(tcx.typeck_root_def_id(def_id.to_def_id()))
         }
         Node::Item(item) => match item.kind {
-            ItemKind::OpaqueTy(hir::OpaqueTy {
+            ItemKind::OpaqueTy(&hir::OpaqueTy {
                 origin:
                     hir::OpaqueTyOrigin::FnReturn(fn_def_id) | hir::OpaqueTyOrigin::AsyncFn(fn_def_id),
                 in_trait,

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -686,7 +686,7 @@ pub(super) fn type_param_predicates(
                 ItemKind::Fn(.., generics, _)
                 | ItemKind::Impl(&hir::Impl { generics, .. })
                 | ItemKind::TyAlias(_, generics)
-                | ItemKind::OpaqueTy(OpaqueTy {
+                | ItemKind::OpaqueTy(&OpaqueTy {
                     generics,
                     origin: hir::OpaqueTyOrigin::TyAlias { .. },
                     ..

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -556,7 +556,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                     });
                 }
             }
-            hir::ItemKind::OpaqueTy(hir::OpaqueTy {
+            hir::ItemKind::OpaqueTy(&hir::OpaqueTy {
                 origin: hir::OpaqueTyOrigin::FnReturn(parent) | hir::OpaqueTyOrigin::AsyncFn(parent),
                 generics,
                 ..

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -435,7 +435,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty
                     ..
                 }) => opaque::find_opaque_ty_constraints_for_tait(tcx, def_id),
                 // Opaque types desugared from `impl Trait`.
-                ItemKind::OpaqueTy(OpaqueTy {
+                ItemKind::OpaqueTy(&OpaqueTy {
                     origin:
                         hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner),
                     in_trait,