Simplify an ObjectData field

compiler/rustc_middle/src/traits/mod.rs

@@ -653,7 +653,7 @@ pub enum ImplSource<'tcx, N> {
     Param(Vec<N>, ty::BoundConstness),
 
     /// Virtual calls through an object.
-    Object(ImplSourceObjectData<'tcx, N>),
+    Object(ImplSourceObjectData<N>),
 
     /// Successful resolution for a builtin trait.
     Builtin(Vec<N>),
@@ -735,7 +735,7 @@ pub fn map<M, F>(self, f: F) -> ImplSource<'tcx, M>
             ImplSource::Param(n, ct) => ImplSource::Param(n.into_iter().map(f).collect(), ct),
             ImplSource::Builtin(n) => ImplSource::Builtin(n.into_iter().map(f).collect()),
             ImplSource::Object(o) => ImplSource::Object(ImplSourceObjectData {
-                upcast_trait_ref: o.upcast_trait_ref,
+                upcast_trait_def_id: o.upcast_trait_def_id,
                 vtable_base: o.vtable_base,
                 nested: o.nested.into_iter().map(f).collect(),
             }),
@@ -835,9 +835,9 @@ pub struct ImplSourceTraitUpcastingData<N> {
 
 #[derive(PartialEq, Eq, Clone, TyEncodable, TyDecodable, HashStable, Lift)]
 #[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceObjectData<'tcx, N> {
+pub struct ImplSourceObjectData<N> {
     /// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`.
-    pub upcast_trait_ref: ty::PolyTraitRef<'tcx>,
+    pub upcast_trait_def_id: DefId,
 
     /// The vtable is formed by concatenating together the method lists of
     /// the base object trait and all supertraits, pointers to supertrait vtable will

compiler/rustc_middle/src/traits/structural_impls.rs

@@ -82,12 +82,12 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     }
 }
 
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceObjectData<'tcx, N> {
+impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceObjectData<N> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
             "ImplSourceObjectData(upcast={:?}, vtable_base={}, nested={:?})",
-            self.upcast_trait_ref, self.vtable_base, self.nested
+            self.upcast_trait_def_id, self.vtable_base, self.nested
         )
     }
 }

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -486,7 +486,7 @@ fn confirm_object_candidate(
         &mut self,
         obligation: &TraitObligation<'tcx>,
         index: usize,
-    ) -> Result<ImplSourceObjectData<'tcx, PredicateObligation<'tcx>>, SelectionError<'tcx>> {
+    ) -> Result<ImplSourceObjectData<PredicateObligation<'tcx>>, SelectionError<'tcx>> {
         let tcx = self.tcx();
         debug!(?obligation, ?index, "confirm_object_candidate");
 
@@ -653,7 +653,11 @@ fn confirm_object_candidate(
             (unnormalized_upcast_trait_ref, ty::Binder::dummy(object_trait_ref)),
         );
 
-        Ok(ImplSourceObjectData { upcast_trait_ref, vtable_base, nested })
+        Ok(ImplSourceObjectData {
+            upcast_trait_def_id: upcast_trait_ref.def_id(),
+            vtable_base,
+            nested,
+        })
     }
 
     fn confirm_fn_pointer_candidate(

compiler/rustc_trait_selection/src/traits/util.rs

@@ -243,12 +243,12 @@ pub fn upcast_choices<'tcx>(
 /// `object.upcast_trait_ref`) within the vtable for `object`.
 pub fn get_vtable_index_of_object_method<'tcx, N>(
     tcx: TyCtxt<'tcx>,
-    object: &super::ImplSourceObjectData<'tcx, N>,
+    object: &super::ImplSourceObjectData<N>,
     method_def_id: DefId,
 ) -> Option<usize> {
     // Count number of methods preceding the one we are selecting and
     // add them to the total offset.
-    tcx.own_existential_vtable_entries(object.upcast_trait_ref.def_id())
+    tcx.own_existential_vtable_entries(object.upcast_trait_def_id)
         .iter()
         .copied()
         .position(|def_id| def_id == method_def_id)