diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs
index 6bcdfd6394a94..0953f262ebff4 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
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..08187c37a1a22 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),
             }
         }
     }
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 5c8a76401d233..45c8f44569c18 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)
             }
 
@@ -317,8 +317,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     fn confirm_auto_impl_candidate(
         &mut self,
         obligation: &TraitObligation<'tcx>,
-        trait_def_id: DefId,
     ) -> ImplSourceAutoImplData<PredicateObligation<'tcx>> {
+        let trait_def_id = obligation.predicate.def_id();
         debug!(?obligation, ?trait_def_id, "confirm_auto_impl_candidate");
 
         let self_ty = self.infcx.shallow_resolve(obligation.predicate.self_ty());
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 8f2a6f337baad..ac3c9ebbdb455 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"