Apply EarlyBinder only to TraitRef in ImplTraitHeader

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -1888,13 +1888,13 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             .tcx
             .all_impls(trait_pred.def_id())
             .filter_map(|def_id| {
-                let imp = self.tcx.impl_trait_header(def_id).unwrap().skip_binder();
+                let imp = self.tcx.impl_trait_header(def_id).unwrap();
                 if imp.polarity == ty::ImplPolarity::Negative
                     || !self.tcx.is_user_visible_dep(def_id.krate)
                 {
                     return None;
                 }
-                let imp = imp.trait_ref;
+                let imp = imp.trait_ref.skip_binder();
 
                 self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false).map(
                     |similarity| ImplCandidate { trait_ref: imp, similarity, impl_def_id: def_id },
@@ -2078,12 +2078,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 .all_impls(def_id)
                 // Ignore automatically derived impls and `!Trait` impls.
                 .filter_map(|def_id| self.tcx.impl_trait_header(def_id))
-                .map(ty::EarlyBinder::instantiate_identity)
-                .filter(|header| {
-                    header.polarity != ty::ImplPolarity::Negative
-                        || self.tcx.is_automatically_derived(def_id)
+                .filter_map(|header| {
+                    (header.polarity != ty::ImplPolarity::Negative
+                        || self.tcx.is_automatically_derived(def_id))
+                    .then(|| header.trait_ref.instantiate_identity())
                 })
-                .map(|header| header.trait_ref)
                 .filter(|trait_ref| {
                     let self_ty = trait_ref.self_ty();
                     // Avoid mentioning type parameters.

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

@@ -562,7 +562,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // and so forth that we need to.
                 let impl_trait_header = self.tcx().impl_trait_header(impl_def_id).unwrap();
                 if !drcx
-                    .args_may_unify(obligation_args, impl_trait_header.skip_binder().trait_ref.args)
+                    .args_may_unify(obligation_args, impl_trait_header.trait_ref.skip_binder().args)
                 {
                     return;
                 }
@@ -577,7 +577,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 if self.reject_fn_ptr_impls(
                     impl_def_id,
                     obligation,
-                    impl_trait_header.skip_binder().trait_ref.self_ty(),
+                    impl_trait_header.trait_ref.skip_binder().self_ty(),
                 ) {
                     return;
                 }

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

@@ -42,7 +42,7 @@ use rustc_middle::ty::_match::MatchAgainstFreshVars;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::relate::TypeRelation;
 use rustc_middle::ty::GenericArgsRef;
-use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
+use rustc_middle::ty::{self, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
 use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_span::symbol::sym;
 use rustc_span::Symbol;
@@ -2441,7 +2441,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
     fn match_impl(
         &mut self,
         impl_def_id: DefId,
-        impl_trait_header: EarlyBinder<ty::ImplTraitHeader<'tcx>>,
+        impl_trait_header: ty::ImplTraitHeader<'tcx>,
         obligation: &PolyTraitObligation<'tcx>,
     ) -> Result<Normalized<'tcx, GenericArgsRef<'tcx>>, ()> {
         let placeholder_obligation =
@@ -2450,8 +2450,8 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
 
         let impl_args = self.infcx.fresh_args_for_item(obligation.cause.span, impl_def_id);
 
-        let impl_trait_header = impl_trait_header.instantiate(self.tcx(), impl_args);
-        if impl_trait_header.references_error() {
+        let trait_ref = impl_trait_header.trait_ref.instantiate(self.tcx(), impl_args);
+        if trait_ref.references_error() {
             return Err(());
         }
 
@@ -2464,7 +2464,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                     obligation.param_env,
                     obligation.cause.clone(),
                     obligation.recursion_depth + 1,
-                    impl_trait_header.trait_ref,
+                    trait_ref,
                 )
             });
 

compiler/rustc_trait_selection/src/traits/specialize/mod.rs

@@ -169,7 +169,7 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId,
         }
     }
 
-    let impl1_trait_header = tcx.impl_trait_header(impl1_def_id).unwrap().instantiate_identity();
+    let impl1_trait_header = tcx.impl_trait_header(impl1_def_id).unwrap();
 
     // We determine whether there's a subset relationship by:
     //
@@ -198,7 +198,7 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId,
     fulfill_implication(
         &infcx,
         penv,
-        impl1_trait_header.trait_ref,
+        impl1_trait_header.trait_ref.instantiate_identity(),
         impl1_def_id,
         impl2_def_id,
         |_, _| ObligationCause::dummy(),