diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs
index 6bcdfd6394a94..11758599cffa1 100644
--- a/compiler/rustc_middle/src/traits/select.rs
+++ b/compiler/rustc_middle/src/traits/select.rs
@@ -115,7 +115,7 @@ pub enum SelectionCandidate<'tcx> {
 
     ParamCandidate(ty::PolyTraitPredicate<'tcx>),
     ImplCandidate(DefId),
-    AutoImplCandidate(DefId),
+    AutoImplCandidate,
 
     /// This is a trait matching with a projected type as `Self`, and we found
     /// an applicable bound in the trait definition. The `usize` is an index
@@ -143,7 +143,7 @@ pub enum SelectionCandidate<'tcx> {
     /// Builtin implementation of `Pointee`.
     PointeeCandidate,
 
-    TraitAliasCandidate(DefId),
+    TraitAliasCandidate,
 
     /// Matching `dyn Trait` with a supertrait of `Trait`. The index is the
     /// position in the iterator returned by
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 9a8331614b0e8..f6c0930eb5f37 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -625,7 +625,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     }
                 }
 
-                _ => candidates.vec.push(AutoImplCandidate(def_id)),
+                _ => candidates.vec.push(AutoImplCandidate),
             }
         }
     }
@@ -914,7 +914,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let def_id = obligation.predicate.def_id();
 
         if self.tcx().is_trait_alias(def_id) {
-            candidates.vec.push(TraitAliasCandidate(def_id));
+            candidates.vec.push(TraitAliasCandidate);
         }
     }
 
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 5c8a76401d233..98c99e9ad4fb6 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -64,8 +64,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 ImplSource::UserDefined(self.confirm_impl_candidate(obligation, impl_def_id))
             }
 
-            AutoImplCandidate(trait_def_id) => {
-                let data = self.confirm_auto_impl_candidate(obligation, trait_def_id);
+            AutoImplCandidate => {
+                let data = self.confirm_auto_impl_candidate(obligation);
                 ImplSource::AutoImpl(data)
             }
 
@@ -100,8 +100,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
             PointeeCandidate => ImplSource::Pointee(ImplSourcePointeeData),
 
-            TraitAliasCandidate(alias_def_id) => {
-                let data = self.confirm_trait_alias_candidate(obligation, alias_def_id);
+            TraitAliasCandidate => {
+                let data = self.confirm_trait_alias_candidate(obligation);
                 ImplSource::TraitAlias(data)
             }
 
@@ -317,13 +317,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     fn confirm_auto_impl_candidate(
         &mut self,
         obligation: &TraitObligation<'tcx>,
-        trait_def_id: DefId,
     ) -> ImplSourceAutoImplData<PredicateObligation<'tcx>> {
-        debug!(?obligation, ?trait_def_id, "confirm_auto_impl_candidate");
+        debug!(?obligation, "confirm_auto_impl_candidate");
 
         let self_ty = self.infcx.shallow_resolve(obligation.predicate.self_ty());
         let types = self.constituent_types_for_ty(self_ty);
-        self.vtable_auto_impl(obligation, trait_def_id, types)
+        self.vtable_auto_impl(obligation, obligation.predicate.def_id(), types)
     }
 
     /// See `confirm_auto_impl_candidate`.
@@ -658,10 +657,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     fn confirm_trait_alias_candidate(
         &mut self,
         obligation: &TraitObligation<'tcx>,
-        alias_def_id: DefId,
     ) -> ImplSourceTraitAliasData<'tcx, PredicateObligation<'tcx>> {
-        debug!(?obligation, ?alias_def_id, "confirm_trait_alias_candidate");
+        debug!(?obligation, "confirm_trait_alias_candidate");
 
+        let alias_def_id = obligation.predicate.def_id();
         let predicate = self.infcx().replace_bound_vars_with_placeholders(obligation.predicate);
         let trait_ref = predicate.trait_ref;
         let trait_def_id = trait_ref.def_id;
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 8f2a6f337baad..c9c47d6fb5456 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1150,7 +1150,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     // const projection
                     ProjectionCandidate(_, ty::BoundConstness::ConstIfConst) => {}
                     // auto trait impl
-                    AutoImplCandidate(..) => {}
+                    AutoImplCandidate => {}
                     // generator, this will raise error in other places
                     // or ignore error with const_async_blocks feature
                     GeneratorCandidate => {}
@@ -1568,7 +1568,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // This is a fix for #53123 and prevents winnowing from accidentally extending the
         // lifetime of a variable.
         match (&other.candidate, &victim.candidate) {
-            (_, AutoImplCandidate(..)) | (AutoImplCandidate(..), _) => {
+            (_, AutoImplCandidate) | (AutoImplCandidate, _) => {
                 bug!(
                     "default implementations shouldn't be recorded \
                     when there are other valid candidates"
@@ -1638,7 +1638,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { .. }
-                | TraitAliasCandidate(..)
+                | TraitAliasCandidate
                 | ObjectCandidate(_)
                 | ProjectionCandidate(..),
             ) => !is_global(cand),
@@ -1656,7 +1656,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { has_nested: true }
-                | TraitAliasCandidate(..),
+                | TraitAliasCandidate,
                 ParamCandidate(ref cand),
             ) => {
                 // Prefer these to a global where-clause bound
@@ -1686,7 +1686,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { .. }
-                | TraitAliasCandidate(..),
+                | TraitAliasCandidate,
             ) => true,
 
             (
@@ -1698,7 +1698,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { .. }
-                | TraitAliasCandidate(..),
+                | TraitAliasCandidate,
                 ObjectCandidate(_) | ProjectionCandidate(..),
             ) => false,
 
@@ -1779,7 +1779,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { has_nested: true }
-                | TraitAliasCandidate(..),
+                | TraitAliasCandidate,
                 ImplCandidate(_)
                 | ClosureCandidate
                 | GeneratorCandidate
@@ -1788,7 +1788,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 | BuiltinUnsizeCandidate
                 | TraitUpcastingUnsizeCandidate(_)
                 | BuiltinCandidate { has_nested: true }
-                | TraitAliasCandidate(..),
+                | TraitAliasCandidate,
             ) => false,
         }
     }