Auto merge of #106696 - kylematsuda:early-binder, r=lcnr

Switch to `EarlyBinder` for `const_param_default` and `impl_trait_ref` queries

Part of the work to close #105779 and implement https://github.com/rust-lang/types-team/issues/78.

Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This PR adds `EarlyBinder` to the return type of  `const_param_default` and `impl_trait_ref`, and removes their `bound_X` variants.

r? `@lcnr`

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -511,9 +511,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             return tcx.const_error(ty).into();
                         }
                         if !infer_args && has_default {
-                            tcx.bound_const_param_default(param.def_id)
+                            tcx.const_param_default(param.def_id).subst(tcx, substs.unwrap()).into()
-                                .subst(tcx, substs.unwrap())
-                                .into()
                         } else {
                             if infer_args {
                                 self.astconv.ct_infer(ty, Some(param), self.span).into()
@@ -2068,7 +2066,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 };
 
                 self.one_bound_for_assoc_type(
-                    || traits::supertraits(tcx, ty::Binder::dummy(trait_ref)),
+                    || traits::supertraits(tcx, ty::Binder::dummy(trait_ref.subst_identity())),
                     || "Self".to_string(),
                     assoc_ident,
                     span,
@@ -2157,7 +2155,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 .is_accessible_from(self.item_def_id(), tcx)
                             && tcx.all_impls(*trait_def_id)
                                 .any(|impl_def_id| {
-                                    let trait_ref = tcx.bound_impl_trait_ref(impl_def_id);
+                                    let trait_ref = tcx.impl_trait_ref(impl_def_id);
                                     trait_ref.map_or(false, |trait_ref| {
                                         let impl_ = trait_ref.subst(
                                             tcx,
@@ -2310,7 +2308,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
                     })
                     .filter_map(|impl_def_id| tcx.impl_trait_ref(impl_def_id))
-                    .map(|impl_| impl_.self_ty())
+                    .map(|impl_| impl_.subst_identity().self_ty())
                     // We don't care about blanket impls.
                     .filter(|self_ty| !self_ty.has_non_region_param())
                     .map(|self_ty| tcx.erase_regions(self_ty).to_string())

compiler/rustc_hir_analysis/src/check/check.rs

@@ -540,7 +540,7 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
                     tcx,
                     it.span,
                     it.owner_id.def_id,
-                    impl_trait_ref,
+                    impl_trait_ref.subst_identity(),
                     &impl_.items,
                 );
                 check_on_unimplemented(tcx, it);

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -616,7 +616,8 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
 ) -> Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed> {
     let impl_m = tcx.opt_associated_item(def_id).unwrap();
     let trait_m = tcx.opt_associated_item(impl_m.trait_item_def_id.unwrap()).unwrap();
-    let impl_trait_ref = tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap();
+    let impl_trait_ref =
+        tcx.impl_trait_ref(impl_m.impl_container(tcx).unwrap()).unwrap().subst_identity();
     let param_env = tcx.param_env(def_id);
 
     // First, check a few of the same things as `compare_impl_method`,
@@ -1684,7 +1685,8 @@ pub(super) fn compare_impl_const_raw(
 ) -> Result<(), ErrorGuaranteed> {
     let impl_const_item = tcx.associated_item(impl_const_item_def);
     let trait_const_item = tcx.associated_item(trait_const_item_def);
-    let impl_trait_ref = tcx.impl_trait_ref(impl_const_item.container_id(tcx)).unwrap();
+    let impl_trait_ref =
+        tcx.impl_trait_ref(impl_const_item.container_id(tcx)).unwrap().subst_identity();
     debug!("compare_const_impl(impl_trait_ref={:?})", impl_trait_ref);
 
     let impl_c_span = tcx.def_span(impl_const_item_def.to_def_id());

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -182,7 +182,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
         hir::ItemKind::Impl(ref impl_) => {
             let is_auto = tcx
                 .impl_trait_ref(def_id)
-                .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id));
+                .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.skip_binder().def_id));
             if let (hir::Defaultness::Default { .. }, true) = (impl_.defaultness, is_auto) {
                 let sp = impl_.of_trait.as_ref().map_or(item.span, |t| t.path.span);
                 let mut err =
@@ -1253,7 +1253,7 @@ fn check_impl<'tcx>(
                 // `#[rustc_reservation_impl]` impls are not real impls and
                 // therefore don't need to be WF (the trait's `Self: Trait` predicate
                 // won't hold).
-                let trait_ref = tcx.impl_trait_ref(item.owner_id).unwrap();
+                let trait_ref = tcx.impl_trait_ref(item.owner_id).unwrap().subst_identity();
                 let trait_ref = wfcx.normalize(
                     ast_trait_ref.path.span,
                     Some(WellFormedLoc::Ty(item.hir_id().expect_owner().def_id)),
@@ -1350,7 +1350,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
                     // is incorrect when dealing with unused substs, for example
                     // for `struct Foo<const N: usize, const M: usize = { 1 - 2 }>`
                     // we should eagerly error.
-                    let default_ct = tcx.const_param_default(param.def_id);
+                    let default_ct = tcx.const_param_default(param.def_id).subst_identity();
                     if !default_ct.needs_subst() {
                         wfcx.register_wf_obligation(
                             tcx.def_span(param.def_id),
@@ -1396,7 +1396,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             GenericParamDefKind::Const { .. } => {
                 // If the param has a default, ...
                 if is_our_default(param) {
-                    let default_ct = tcx.const_param_default(param.def_id);
+                    let default_ct = tcx.const_param_default(param.def_id).subst_identity();
                     // ... and it's not a dependent default, ...
                     if !default_ct.needs_subst() {
                         // ... then substitute it with the default.

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -192,7 +192,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
     let source = tcx.type_of(impl_did);
     assert!(!source.has_escaping_bound_vars());
     let target = {
-        let trait_ref = tcx.impl_trait_ref(impl_did).unwrap();
+        let trait_ref = tcx.impl_trait_ref(impl_did).unwrap().subst_identity();
         assert_eq!(trait_ref.def_id, dispatch_from_dyn_trait);
 
         trait_ref.substs.type_at(1)
@@ -354,7 +354,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn
     });
 
     let source = tcx.type_of(impl_did);
-    let trait_ref = tcx.impl_trait_ref(impl_did).unwrap();
+    let trait_ref = tcx.impl_trait_ref(impl_did).unwrap().subst_identity();
     assert_eq!(trait_ref.def_id, coerce_unsized_trait);
     let target = trait_ref.substs.type_at(1);
     debug!("visit_implementation_of_coerce_unsized: {:?} -> {:?} (bound)", source, target);

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -128,7 +128,7 @@ fn coherent_trait(tcx: TyCtxt<'_>, def_id: DefId) {
 
     let impls = tcx.hir().trait_impls(def_id);
     for &impl_def_id in impls {
-        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
 
         check_impl(tcx, impl_def_id, trait_ref);
         check_object_overlap(tcx, impl_def_id, trait_ref);

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -21,7 +21,7 @@ pub(crate) fn orphan_check_impl(
     tcx: TyCtxt<'_>,
     impl_def_id: LocalDefId,
 ) -> Result<(), ErrorGuaranteed> {
-    let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+    let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
     trait_ref.error_reported()?;
 
     let ret = do_orphan_check_impl(tcx, trait_ref, impl_def_id);

compiler/rustc_hir_analysis/src/coherence/unsafety.rs

@@ -14,6 +14,7 @@ pub(super) fn check_item(tcx: TyCtxt<'_>, def_id: LocalDefId) {
     let hir::ItemKind::Impl(ref impl_) = item.kind else { bug!() };
 
     if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) {
+        let trait_ref = trait_ref.subst_identity();
         let trait_def = tcx.trait_def(trait_ref.def_id);
         let unsafe_attr =
             impl_.generics.params.iter().find(|p| p.pure_wrt_drop).map(|_| "may_dangle");

compiler/rustc_hir_analysis/src/collect.rs

@@ -1339,18 +1339,22 @@ fn suggest_impl_trait<'tcx>(
     None
 }
 
-fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::TraitRef<'_>> {
+fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::EarlyBinder<ty::TraitRef<'_>>> {
     let icx = ItemCtxt::new(tcx, def_id);
     let item = tcx.hir().expect_item(def_id.expect_local());
     match item.kind {
-        hir::ItemKind::Impl(ref impl_) => impl_.of_trait.as_ref().map(|ast_trait_ref| {
+        hir::ItemKind::Impl(ref impl_) => impl_
-            let selfty = tcx.type_of(def_id);
+            .of_trait
-            icx.astconv().instantiate_mono_trait_ref(
+            .as_ref()
-                ast_trait_ref,
+            .map(|ast_trait_ref| {
-                selfty,
+                let selfty = tcx.type_of(def_id);
-                check_impl_constness(tcx, impl_.constness, ast_trait_ref),
+                icx.astconv().instantiate_mono_trait_ref(
-            )
+                    ast_trait_ref,
-        }),
+                    selfty,
+                    check_impl_constness(tcx, impl_.constness, ast_trait_ref),
+                )
+            })
+            .map(ty::EarlyBinder),
         _ => bug!(),
     }
 }

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -87,7 +87,8 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
         Node::Item(item) => match item.kind {
             ItemKind::Impl(ref impl_) => {
                 if impl_.defaultness.is_default() {
-                    is_default_impl_trait = tcx.impl_trait_ref(def_id).map(ty::Binder::dummy);
+                    is_default_impl_trait =
+                        tcx.impl_trait_ref(def_id).map(|t| ty::Binder::dummy(t.subst_identity()));
                 }
                 &impl_.generics
             }
@@ -251,7 +252,7 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
     // for details.
     if let Node::Item(&Item { kind: ItemKind::Impl { .. }, .. }) = node {
         let self_ty = tcx.type_of(def_id);
-        let trait_ref = tcx.impl_trait_ref(def_id);
+        let trait_ref = tcx.impl_trait_ref(def_id).map(ty::EarlyBinder::subst_identity);
         cgp::setup_constraining_predicates(
             tcx,
             &mut predicates,

compiler/rustc_hir_analysis/src/impl_wf_check.rs

@@ -85,7 +85,7 @@ fn enforce_impl_params_are_constrained(tcx: TyCtxt<'_>, impl_def_id: LocalDefId)
     }
     let impl_generics = tcx.generics_of(impl_def_id);
     let impl_predicates = tcx.predicates_of(impl_def_id);
-    let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
+    let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).map(ty::EarlyBinder::subst_identity);
 
     let mut input_parameters = cgp::parameters_for_impl(impl_self_ty, impl_trait_ref);
     cgp::identify_constrained_generic_params(

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -90,7 +90,7 @@ pub(super) fn check_min_specialization(tcx: TyCtxt<'_>, impl_def_id: LocalDefId)
 
 fn parent_specialization_node(tcx: TyCtxt<'_>, impl1_def_id: LocalDefId) -> Option<Node> {
     let trait_ref = tcx.impl_trait_ref(impl1_def_id)?;
-    let trait_def = tcx.trait_def(trait_ref.def_id);
+    let trait_def = tcx.trait_def(trait_ref.skip_binder().def_id);
 
     let impl2_node = trait_def.ancestors(tcx, impl1_def_id.to_def_id()).ok()?.nth(1)?;
 
@@ -207,7 +207,7 @@ fn unconstrained_parent_impl_substs<'tcx>(
     let impl_generic_predicates = tcx.predicates_of(impl_def_id);
     let mut unconstrained_parameters = FxHashSet::default();
     let mut constrained_params = FxHashSet::default();
-    let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
+    let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).map(ty::EarlyBinder::subst_identity);
 
     // Unfortunately the functions in `constrained_generic_parameters` don't do
     // what we want here. We want only a list of constrained parameters while
@@ -370,7 +370,7 @@ fn check_predicates<'tcx>(
     });
 
     // Include the well-formed predicates of the type parameters of the impl.
-    for arg in tcx.impl_trait_ref(impl1_def_id).unwrap().substs {
+    for arg in tcx.impl_trait_ref(impl1_def_id).unwrap().subst_identity().substs {
         let infcx = &tcx.infer_ctxt().build();
         let obligations = wf::obligations(
             infcx,

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -1224,9 +1224,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     GenericParamDefKind::Const { has_default } => {
                         if !infer_args && has_default {
-                            tcx.bound_const_param_default(param.def_id)
+                            tcx.const_param_default(param.def_id).subst(tcx, substs.unwrap()).into()
-                                .subst(tcx, substs.unwrap())
-                                .into()
                         } else {
                             self.fcx.var_for_def(self.span, param)
                         }

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -1072,7 +1072,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // the impl, if local to crate (item may be defaulted), else nothing.
                     let Some(item) = self.associated_value(impl_did, item_name).or_else(|| {
                         let impl_trait_ref = self.tcx.impl_trait_ref(impl_did)?;
-                        self.associated_value(impl_trait_ref.def_id, item_name)
+                        self.associated_value(impl_trait_ref.skip_binder().def_id, item_name)
                     }) else {
                         continue;
                     };
@@ -1090,7 +1090,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let insertion = match self.tcx.impl_trait_ref(impl_did) {
                         None => String::new(),
                         Some(trait_ref) => {
-                            format!(" of the trait `{}`", self.tcx.def_path_str(trait_ref.def_id))
+                            format!(
+                                " of the trait `{}`",
+                                self.tcx.def_path_str(trait_ref.skip_binder().def_id)
+                            )
                         }
                     };
 
@@ -1121,7 +1124,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     if let Some(sugg_span) = sugg_span
                         && let Some(trait_ref) = self.tcx.impl_trait_ref(impl_did) {
-                        let path = self.tcx.def_path_str(trait_ref.def_id);
+                        let path = self.tcx.def_path_str(trait_ref.skip_binder().def_id);
 
                         let ty = match item.kind {
                             ty::AssocKind::Const | ty::AssocKind::Type => rcvr_ty,
@@ -2616,7 +2619,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             self.tcx.impl_polarity(*imp_did) == ty::ImplPolarity::Negative
                         })
                         .any(|imp_did| {
-                            let imp = self.tcx.impl_trait_ref(imp_did).unwrap();
+                            let imp = self.tcx.impl_trait_ref(imp_did).unwrap().subst_identity();
                             let imp_simp =
                                 simplify_type(self.tcx, imp.self_ty(), TreatParams::AsPlaceholder);
                             imp_simp.map_or(false, |s| s == simp_rcvr_ty)

compiler/rustc_infer/src/infer/error_reporting/note.rs

@@ -320,6 +320,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             .impl_trait_ref(impl_def_id)
             else { return; };
         let trait_substs = trait_ref
+            .subst_identity()
             // Replace the explicit self type with `Self` for better suggestion rendering
             .with_self_ty(self.tcx, self.tcx.mk_ty_param(0, kw::SelfUpper))
             .substs;

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1555,7 +1555,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 self.tables.impl_defaultness.set(def_id.index, *defaultness);
                 self.tables.constness.set(def_id.index, *constness);
 
-                let trait_ref = self.tcx.impl_trait_ref(def_id);
+                let trait_ref = self.tcx.impl_trait_ref(def_id).map(ty::EarlyBinder::skip_binder);
                 if let Some(trait_ref) = trait_ref {
                     let trait_def = self.tcx.trait_def(trait_ref.def_id);
                     if let Ok(mut an) = trait_def.ancestors(self.tcx, def_id) {
@@ -1899,6 +1899,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         for id in tcx.hir().items() {
             if matches!(tcx.def_kind(id.owner_id), DefKind::Impl) {
                 if let Some(trait_ref) = tcx.impl_trait_ref(id.owner_id) {
+                    let trait_ref = trait_ref.subst_identity();
+
                     let simplified_self_ty = fast_reject::simplify_type(
                         self.tcx,
                         trait_ref.self_ty(),

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -359,8 +359,8 @@ define_tables! {
     variances_of: Table<DefIndex, LazyArray<ty::Variance>>,
     fn_sig: Table<DefIndex, LazyValue<ty::PolyFnSig<'static>>>,
     codegen_fn_attrs: Table<DefIndex, LazyValue<CodegenFnAttrs>>,
-    impl_trait_ref: Table<DefIndex, LazyValue<ty::TraitRef<'static>>>,
+    impl_trait_ref: Table<DefIndex, LazyValue<ty::EarlyBinder<ty::TraitRef<'static>>>>,
-    const_param_default: Table<DefIndex, LazyValue<rustc_middle::ty::Const<'static>>>,
+    const_param_default: Table<DefIndex, LazyValue<ty::EarlyBinder<rustc_middle::ty::Const<'static>>>>,
     object_lifetime_default: Table<DefIndex, LazyValue<ObjectLifetimeDefault>>,
     optimized_mir: Table<DefIndex, LazyValue<mir::Body<'static>>>,
     mir_for_ctfe: Table<DefIndex, LazyValue<mir::Body<'static>>>,

compiler/rustc_middle/src/hir/mod.rs

@@ -102,6 +102,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
     pub fn impl_subject(self, def_id: DefId) -> ImplSubject<'tcx> {
         self.impl_trait_ref(def_id)
+            .map(|t| t.subst_identity())
             .map(ImplSubject::Trait)
             .unwrap_or_else(|| ImplSubject::Inherent(self.type_of(def_id)))
     }

compiler/rustc_middle/src/query/mod.rs

@@ -142,7 +142,7 @@ rustc_queries! {
 
     /// Given the def_id of a const-generic parameter, computes the associated default const
     /// parameter. e.g. `fn example<const N: usize=3>` called on `N` would return `3`.
-    query const_param_default(param: DefId) -> ty::Const<'tcx> {
+    query const_param_default(param: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> {
         desc { |tcx| "computing const default for a given parameter `{}`", tcx.def_path_str(param)  }
         cache_on_disk_if { param.is_local() }
         separate_provide_extern
@@ -737,7 +737,7 @@ rustc_queries! {
 
     /// Given an `impl_id`, return the trait it implements.
     /// Return `None` if this is an inherent impl.
-    query impl_trait_ref(impl_id: DefId) -> Option<ty::TraitRef<'tcx>> {
+    query impl_trait_ref(impl_id: DefId) -> Option<ty::EarlyBinder<ty::TraitRef<'tcx>>> {
         desc { |tcx| "computing trait implemented by `{}`", tcx.def_path_str(impl_id) }
         cache_on_disk_if { impl_id.is_local() }
         separate_provide_extern

compiler/rustc_middle/src/ty/consts.rs

@@ -239,7 +239,7 @@ impl<'tcx> Const<'tcx> {
     }
 }
 
-pub fn const_param_default(tcx: TyCtxt<'_>, def_id: DefId) -> Const<'_> {
+pub fn const_param_default(tcx: TyCtxt<'_>, def_id: DefId) -> ty::EarlyBinder<Const<'_>> {
     let default_def_id = match tcx.hir().get_by_def_id(def_id.expect_local()) {
         hir::Node::GenericParam(hir::GenericParam {
             kind: hir::GenericParamKind::Const { default: Some(ac), .. },
@@ -250,5 +250,5 @@ pub fn const_param_default(tcx: TyCtxt<'_>, def_id: DefId) -> Const<'_> {
             "`const_param_default` expected a generic parameter with a constant"
         ),
     };
-    Const::from_anon_const(tcx, default_def_id)
+    ty::EarlyBinder(Const::from_anon_const(tcx, default_def_id))
 }

compiler/rustc_middle/src/ty/generics.rs

@@ -88,7 +88,7 @@ impl GenericParamDef {
                 Some(tcx.bound_type_of(self.def_id).map_bound(|t| t.into()))
             }
             GenericParamDefKind::Const { has_default } if has_default => {
-                Some(tcx.bound_const_param_default(self.def_id).map_bound(|c| c.into()))
+                Some(tcx.const_param_default(self.def_id).map_bound(|c| c.into()))
             }
             _ => None,
         }

compiler/rustc_middle/src/ty/mod.rs

@@ -2187,8 +2187,10 @@ impl<'tcx> TyCtxt<'tcx> {
     ) -> Option<ImplOverlapKind> {
         // If either trait impl references an error, they're allowed to overlap,
         // as one of them essentially doesn't exist.
-        if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.references_error())
+        if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.subst_identity().references_error())
-            || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.references_error())
+            || self
+                .impl_trait_ref(def_id2)
+                .map_or(false, |tr| tr.subst_identity().references_error())
         {
             return Some(ImplOverlapKind::Permitted { marker: false });
         }
@@ -2218,7 +2220,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let is_marker_overlap = {
             let is_marker_impl = |def_id: DefId| -> bool {
                 let trait_ref = self.impl_trait_ref(def_id);
-                trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
+                trait_ref.map_or(false, |tr| self.trait_def(tr.skip_binder().def_id).is_marker)
             };
             is_marker_impl(def_id1) && is_marker_impl(def_id2)
         };
@@ -2364,7 +2366,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
     /// If it implements no trait, returns `None`.
     pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
-        self.impl_trait_ref(def_id).map(|tr| tr.def_id)
+        self.impl_trait_ref(def_id).map(|tr| tr.skip_binder().def_id)
     }
 
     /// If the given `DefId` describes an item belonging to a trait,

compiler/rustc_middle/src/ty/parameterized.rs

@@ -32,6 +32,10 @@ impl<T: ParameterizedOverTcx> ParameterizedOverTcx for ty::Binder<'static, T> {
     type Value<'tcx> = ty::Binder<'tcx, T::Value<'tcx>>;
 }
 
+impl<T: ParameterizedOverTcx> ParameterizedOverTcx for ty::EarlyBinder<T> {
+    type Value<'tcx> = ty::EarlyBinder<T::Value<'tcx>>;
+}
+
 #[macro_export]
 macro_rules! trivially_parameterized_over_tcx {
     ($($ty:ty),+ $(,)?) => {

compiler/rustc_middle/src/ty/print/mod.rs

@@ -116,7 +116,7 @@ pub trait Printer<'tcx>: Sized {
             DefPathData::Impl => {
                 let generics = self.tcx().generics_of(def_id);
                 let self_ty = self.tcx().bound_type_of(def_id);
-                let impl_trait_ref = self.tcx().bound_impl_trait_ref(def_id);
+                let impl_trait_ref = self.tcx().impl_trait_ref(def_id);
                 let (self_ty, impl_trait_ref) = if substs.len() >= generics.count() {
                     (
                         self_ty.subst(self.tcx(), substs),

compiler/rustc_middle/src/ty/subst.rs

@@ -713,6 +713,10 @@ impl<'tcx, T: TypeFoldable<'tcx>> ty::EarlyBinder<T> {
         let mut folder = SubstFolder { tcx, substs, binders_passed: 0 };
         self.0.fold_with(&mut folder)
     }
+
+    pub fn subst_identity(self) -> T {
+        self.0
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////

compiler/rustc_middle/src/ty/util.rs

@@ -652,13 +652,6 @@ impl<'tcx> TyCtxt<'tcx> {
         ty::EarlyBinder(self.fn_sig(def_id))
     }
 
-    pub fn bound_impl_trait_ref(
-        self,
-        def_id: DefId,
-    ) -> Option<ty::EarlyBinder<ty::TraitRef<'tcx>>> {
-        self.impl_trait_ref(def_id).map(|i| ty::EarlyBinder(i))
-    }
-
     pub fn bound_explicit_item_bounds(
         self,
         def_id: DefId,
@@ -673,10 +666,6 @@ impl<'tcx> TyCtxt<'tcx> {
         ty::EarlyBinder(self.item_bounds(def_id))
     }
 
-    pub fn bound_const_param_default(self, def_id: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> {
-        ty::EarlyBinder(self.const_param_default(def_id))
-    }
-
     pub fn bound_predicates_of(
         self,
         def_id: DefId,

compiler/rustc_middle/src/values.rs

@@ -94,6 +94,18 @@ impl<'tcx> Value<TyCtxt<'tcx>, DepKind> for Representability {
     }
 }
 
+impl<'tcx> Value<TyCtxt<'tcx>, DepKind> for ty::EarlyBinder<Ty<'_>> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>, cycle: &[QueryInfo<DepKind>]) -> Self {
+        ty::EarlyBinder(Ty::from_cycle_error(tcx, cycle))
+    }
+}
+
+impl<'tcx> Value<TyCtxt<'tcx>, DepKind> for ty::EarlyBinder<ty::Binder<'_, ty::FnSig<'_>>> {
+    fn from_cycle_error(tcx: TyCtxt<'tcx>, cycle: &[QueryInfo<DepKind>]) -> Self {
+        ty::EarlyBinder(ty::Binder::from_cycle_error(tcx, cycle))
+    }
+}
+
 // item_and_field_ids should form a cycle where each field contains the
 // type in the next element in the list
 pub fn recursive_type_error(

compiler/rustc_monomorphize/src/collector.rs

@@ -1352,6 +1352,8 @@ fn create_mono_items_for_default_impls<'tcx>(
             );
 
             if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) {
+                let trait_ref = trait_ref.subst_identity();
+
                 let param_env = ty::ParamEnv::reveal_all();
                 let trait_ref = tcx.normalize_erasing_regions(param_env, trait_ref);
                 let overridden_methods = tcx.impl_item_implementor_ids(item.owner_id);

compiler/rustc_passes/src/dead.rs

@@ -266,7 +266,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
             if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of)
                 && self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads)
             {
-                let trait_ref = self.tcx.impl_trait_ref(impl_of).unwrap();
+                let trait_ref = self.tcx.impl_trait_ref(impl_of).unwrap().subst_identity();
                 if let ty::Adt(adt_def, _) = trait_ref.self_ty().kind()
                     && let Some(adt_def_id) = adt_def.did().as_local()
                 {

compiler/rustc_privacy/src/lib.rs

@@ -338,7 +338,7 @@ trait VisibilityLike: Sized {
         let mut find = FindMin { tcx, effective_visibilities, min: Self::MAX };
         find.visit(tcx.type_of(def_id));
         if let Some(trait_ref) = tcx.impl_trait_ref(def_id) {
-            find.visit_trait(trait_ref);
+            find.visit_trait(trait_ref.subst_identity());
         }
         find.min
     }
@@ -838,7 +838,7 @@ impl ReachEverythingInTheInterfaceVisitor<'_, '_> {
                 GenericParamDefKind::Const { has_default } => {
                     self.visit(self.ev.tcx.type_of(param.def_id));
                     if has_default {
-                        self.visit(self.ev.tcx.const_param_default(param.def_id));
+                        self.visit(self.ev.tcx.const_param_default(param.def_id).subst_identity());
                     }
                 }
             }
@@ -858,7 +858,7 @@ impl ReachEverythingInTheInterfaceVisitor<'_, '_> {
 
     fn trait_ref(&mut self) -> &mut Self {
         if let Some(trait_ref) = self.ev.tcx.impl_trait_ref(self.item_def_id) {
-            self.visit_trait(trait_ref);
+            self.visit_trait(trait_ref.subst_identity());
         }
         self
     }

compiler/rustc_trait_selection/src/solve/project_goals.rs

@@ -110,7 +110,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
     ) {
         let tcx = acx.cx.tcx;
         let goal_trait_ref = goal.predicate.projection_ty.trait_ref(tcx);
-        let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap();
+        let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
         let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsPlaceholder };
         if iter::zip(goal_trait_ref.substs, impl_trait_ref.skip_binder().substs)
             .any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -73,7 +73,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
     ) {
         let tcx = acx.cx.tcx;
 
-        let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap();
+        let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
         let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsPlaceholder };
         if iter::zip(goal.predicate.trait_ref.substs, impl_trait_ref.skip_binder().substs)
             .any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -80,7 +80,7 @@ pub fn overlapping_impls(
     let impl1_ref = tcx.impl_trait_ref(impl1_def_id);
     let impl2_ref = tcx.impl_trait_ref(impl2_def_id);
     let may_overlap = match (impl1_ref, impl2_ref) {
-        (Some(a), Some(b)) => iter::zip(a.substs, b.substs)
+        (Some(a), Some(b)) => iter::zip(a.skip_binder().substs, b.skip_binder().substs)
             .all(|(arg1, arg2)| drcx.generic_args_may_unify(arg1, arg2)),
         (None, None) => {
             let self_ty1 = tcx.type_of(impl1_def_id);
@@ -126,7 +126,7 @@ fn with_fresh_ty_vars<'cx, 'tcx>(
     let header = ty::ImplHeader {
         impl_def_id,
         self_ty: tcx.bound_type_of(impl_def_id).subst(tcx, impl_substs),
-        trait_ref: tcx.bound_impl_trait_ref(impl_def_id).map(|i| i.subst(tcx, impl_substs)),
+        trait_ref: tcx.impl_trait_ref(impl_def_id).map(|i| i.subst(tcx, impl_substs)),
         predicates: tcx.predicates_of(impl_def_id).instantiate(tcx, impl_substs).predicates,
     };
 
@@ -461,7 +461,7 @@ pub fn orphan_check(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Result<(), OrphanChe
 
     // We only except this routine to be invoked on implementations
     // of a trait, not inherent implementations.
-    let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+    let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
     debug!("orphan_check: trait_ref={:?}", trait_ref);
 
     // If the *trait* is local to the crate, ok.

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

@@ -27,7 +27,7 @@ pub fn recompute_applicable_impls<'tcx>(
             ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref);
 
         let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
-        let impl_trait_ref = tcx.bound_impl_trait_ref(impl_def_id).unwrap().subst(tcx, impl_substs);
+        let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst(tcx, impl_substs);
         let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref);
 
         if let Err(_) =

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

@@ -1964,7 +1964,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     return None;
                 }
 
-                let imp = self.tcx.impl_trait_ref(def_id).unwrap();
+                let imp = self.tcx.impl_trait_ref(def_id).unwrap().skip_binder();
 
                 self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false)
                     .map(|similarity| ImplCandidate { trait_ref: imp, similarity })
@@ -2062,6 +2062,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         || self.tcx.is_builtin_derive(def_id)
                 })
                 .filter_map(|def_id| self.tcx.impl_trait_ref(def_id))
+                .map(ty::EarlyBinder::subst_identity)
                 .filter(|trait_ref| {
                     let self_ty = trait_ref.self_ty();
                     // Avoid mentioning type parameters.

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

@@ -68,7 +68,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| {
             let impl_substs = self.fresh_substs_for_item(obligation.cause.span, def_id);
-            let impl_trait_ref = tcx.bound_impl_trait_ref(def_id).unwrap().subst(tcx, impl_substs);
+            let impl_trait_ref = tcx.impl_trait_ref(def_id).unwrap().subst(tcx, impl_substs);
 
             let impl_self_ty = impl_trait_ref.self_ty();
 

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -521,8 +521,10 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
 
     let generics = tcx.generics_of(trait_item_def_id);
     let predicates = tcx.predicates_of(trait_item_def_id);
-    let impl_trait_ref =
+    let impl_trait_ref = tcx
-        tcx.impl_trait_ref(impl_def_id).expect("expected impl to correspond to trait");
+        .impl_trait_ref(impl_def_id)
+        .expect("expected impl to correspond to trait")
+        .subst_identity();
     let param_env = tcx.param_env(impl_def_id);
 
     let mut visitor = ReferencesOnlyParentGenerics { tcx, generics, trait_item_def_id };

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

@@ -357,7 +357,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // Before we create the substitutions and everything, first
                 // consider a "quick reject". This avoids creating more types
                 // and so forth that we need to.
-                let impl_trait_ref = self.tcx().bound_impl_trait_ref(impl_def_id).unwrap();
+                let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
                 if self.fast_reject_trait_refs(obligation, &impl_trait_ref.0) {
                     return;
                 }

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

@@ -2335,7 +2335,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         impl_def_id: DefId,
         obligation: &TraitObligation<'tcx>,
     ) -> Normalized<'tcx, SubstsRef<'tcx>> {
-        let impl_trait_ref = self.tcx().bound_impl_trait_ref(impl_def_id).unwrap();
+        let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
         match self.match_impl(impl_def_id, impl_trait_ref, obligation) {
             Ok(substs) => substs,
             Err(()) => {

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

@@ -87,7 +87,7 @@ pub fn translate_substs<'tcx>(
         param_env, source_impl, source_substs, target_node
     );
     let source_trait_ref =
-        infcx.tcx.bound_impl_trait_ref(source_impl).unwrap().subst(infcx.tcx, &source_substs);
+        infcx.tcx.impl_trait_ref(source_impl).unwrap().subst(infcx.tcx, &source_substs);
 
     // translate the Self and Param parts of the substitution, since those
     // vary across impls
@@ -148,7 +148,7 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId,
 
     // create a parameter environment corresponding to a (placeholder) instantiation of impl1
     let penv = tcx.param_env(impl1_def_id);
-    let impl1_trait_ref = tcx.impl_trait_ref(impl1_def_id).unwrap();
+    let impl1_trait_ref = tcx.impl_trait_ref(impl1_def_id).unwrap().subst_identity();
 
     // Create an infcx, taking the predicates of impl1 as assumptions:
     let infcx = tcx.infer_ctxt().build();
@@ -431,7 +431,7 @@ fn report_conflicting_impls<'tcx>(
 pub(crate) fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Option<String> {
     use std::fmt::Write;
 
-    let trait_ref = tcx.impl_trait_ref(impl_def_id)?;
+    let trait_ref = tcx.impl_trait_ref(impl_def_id)?.subst_identity();
     let mut w = "impl".to_owned();
 
     let substs = InternalSubsts::identity_for_item(tcx, impl_def_id);

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

@@ -48,7 +48,7 @@ trait ChildrenExt<'tcx> {
 impl<'tcx> ChildrenExt<'tcx> for Children {
     /// Insert an impl into this set of children without comparing to any existing impls.
     fn insert_blindly(&mut self, tcx: TyCtxt<'tcx>, impl_def_id: DefId) {
-        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
         if let Some(st) = fast_reject::simplify_type(tcx, trait_ref.self_ty(), TreatParams::AsInfer)
         {
             debug!("insert_blindly: impl_def_id={:?} st={:?}", impl_def_id, st);
@@ -63,7 +63,7 @@ impl<'tcx> ChildrenExt<'tcx> for Children {
     /// an impl with a parent. The impl must be present in the list of
     /// children already.
     fn remove_existing(&mut self, tcx: TyCtxt<'tcx>, impl_def_id: DefId) {
-        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
         let vec: &mut Vec<DefId>;
         if let Some(st) = fast_reject::simplify_type(tcx, trait_ref.self_ty(), TreatParams::AsInfer)
         {
@@ -181,7 +181,7 @@ impl<'tcx> ChildrenExt<'tcx> for Children {
             if le && !ge {
                 debug!(
                     "descending as child of TraitRef {:?}",
-                    tcx.impl_trait_ref(possible_sibling).unwrap()
+                    tcx.impl_trait_ref(possible_sibling).unwrap().subst_identity()
                 );
 
                 // The impl specializes `possible_sibling`.
@@ -189,7 +189,7 @@ impl<'tcx> ChildrenExt<'tcx> for Children {
             } else if ge && !le {
                 debug!(
                     "placing as parent of TraitRef {:?}",
-                    tcx.impl_trait_ref(possible_sibling).unwrap()
+                    tcx.impl_trait_ref(possible_sibling).unwrap().subst_identity()
                 );
 
                 replace_children.push(possible_sibling);
@@ -275,7 +275,8 @@ impl<'tcx> GraphExt<'tcx> for Graph {
     ) -> Result<Option<FutureCompatOverlapError<'tcx>>, OverlapError<'tcx>> {
         assert!(impl_def_id.is_local());
 
-        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+        // FIXME: use `EarlyBinder` in `self.children`
+        let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
         let trait_def_id = trait_ref.def_id;
 
         debug!(
@@ -388,7 +389,7 @@ pub(crate) fn assoc_def(
     impl_def_id: DefId,
     assoc_def_id: DefId,
 ) -> Result<LeafDef, ErrorGuaranteed> {
-    let trait_def_id = tcx.impl_trait_ref(impl_def_id).unwrap().def_id;
+    let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
     let trait_def = tcx.trait_def(trait_def_id);
 
     // This function may be called while we are still building the

compiler/rustc_traits/src/chalk/db.rs

@@ -309,7 +309,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
         let binders = binders_for(self.interner, bound_vars);
 
-        let trait_ref = self.interner.tcx.bound_impl_trait_ref(def_id).expect("not an impl");
+        let trait_ref = self.interner.tcx.impl_trait_ref(def_id).expect("not an impl");
         let trait_ref = trait_ref.subst(self.interner.tcx, bound_vars);
 
         let where_clauses = self.where_clauses_for(def_id, bound_vars);
@@ -351,7 +351,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         let all_impls = self.interner.tcx.all_impls(def_id);
         let matched_impls = all_impls.filter(|impl_def_id| {
             use chalk_ir::could_match::CouldMatch;
-            let trait_ref = self.interner.tcx.bound_impl_trait_ref(*impl_def_id).unwrap();
+            let trait_ref = self.interner.tcx.impl_trait_ref(*impl_def_id).unwrap();
             let bound_vars = bound_vars_for_item(self.interner.tcx, *impl_def_id);
 
             let self_ty = trait_ref.map_bound(|t| t.self_ty());
@@ -380,7 +380,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         let trait_def_id = auto_trait_id.0;
         let all_impls = self.interner.tcx.all_impls(trait_def_id);
         for impl_def_id in all_impls {
-            let trait_ref = self.interner.tcx.impl_trait_ref(impl_def_id).unwrap();
+            let trait_ref = self.interner.tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
             let self_ty = trait_ref.self_ty();
             let provides = match (self_ty.kind(), chalk_ty) {
                 (&ty::Adt(impl_adt_def, ..), Adt(id, ..)) => impl_adt_def.did() == id.0.did(),

compiler/rustc_ty_utils/src/implied_bounds.rs

@@ -21,14 +21,16 @@ fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Ty<'_>> {
             assumed_wf_types.extend(liberated_sig.inputs_and_output);
             tcx.intern_type_list(&assumed_wf_types)
         }
-        DefKind::Impl => match tcx.impl_trait_ref(def_id) {
+        DefKind::Impl => {
-            Some(trait_ref) => {
+            match tcx.impl_trait_ref(def_id) {
-                let types: Vec<_> = trait_ref.substs.types().collect();
+                Some(trait_ref) => {
-                tcx.intern_type_list(&types)
+                    let types: Vec<_> = trait_ref.skip_binder().substs.types().collect();
+                    tcx.intern_type_list(&types)
+                }
+                // Only the impl self type
+                None => tcx.intern_type_list(&[tcx.type_of(def_id)]),
             }
-            // Only the impl self type
+        }
-            None => tcx.intern_type_list(&[tcx.type_of(def_id)]),
-        },
         DefKind::AssocConst | DefKind::AssocTy => tcx.assumed_wf_types(tcx.parent(def_id)),
         DefKind::Mod
         | DefKind::Struct

compiler/rustc_ty_utils/src/ty.rs

@@ -289,7 +289,7 @@ fn well_formed_types_in_env(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Predica
         // In a trait impl, we assume that the header trait ref and all its
         // constituents are well-formed.
         NodeKind::TraitImpl => {
-            let trait_ref = tcx.impl_trait_ref(def_id).expect("not an impl");
+            let trait_ref = tcx.impl_trait_ref(def_id).expect("not an impl").subst_identity();
 
             // FIXME(chalk): this has problems because of late-bound regions
             //inputs.extend(trait_ref.substs.iter().flat_map(|arg| arg.walk()));
@@ -360,7 +360,8 @@ fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
 
     let trait_ref = tcx
         .impl_trait_ref(def_id)
-        .unwrap_or_else(|| bug!("issue33140_self_ty called on inherent impl {:?}", def_id));
+        .unwrap_or_else(|| bug!("issue33140_self_ty called on inherent impl {:?}", def_id))
+        .skip_binder();
 
     debug!("issue33140_self_ty({:?}), trait-ref={:?}", def_id, trait_ref);
 

src/librustdoc/clean/blanket_impl.rs

@@ -33,7 +33,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     trait_def_id,
                     impl_def_id
                 );
-                let trait_ref = cx.tcx.bound_impl_trait_ref(impl_def_id).unwrap();
+                let trait_ref = cx.tcx.impl_trait_ref(impl_def_id).unwrap();
                 if !matches!(trait_ref.0.self_ty().kind(), ty::Param(_)) {
                     continue;
                 }

src/librustdoc/clean/inline.rs

@@ -376,7 +376,7 @@ pub(crate) fn build_impl(
     let _prof_timer = cx.tcx.sess.prof.generic_activity("build_impl");
 
     let tcx = cx.tcx;
-    let associated_trait = tcx.impl_trait_ref(did);
+    let associated_trait = tcx.impl_trait_ref(did).map(ty::EarlyBinder::skip_binder);
 
     // Only inline impl if the implemented trait is
     // reachable in rustdoc generated documentation

src/librustdoc/clean/mod.rs

@@ -506,7 +506,9 @@ fn clean_generic_param_def<'tcx>(
                     Some(def.def_id),
                 )),
                 default: match has_default {
-                    true => Some(Box::new(cx.tcx.const_param_default(def.def_id).to_string())),
+                    true => Some(Box::new(
+                        cx.tcx.const_param_default(def.def_id).subst_identity().to_string(),
+                    )),
                     false => None,
                 },
             },

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -786,7 +786,7 @@ fn trait_impls_for<'a>(
         tcx.find_map_relevant_impl(trait_, ty, |impl_| {
             let trait_ref = tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
             // Check if these are the same type.
-            let impl_type = trait_ref.self_ty();
+            let impl_type = trait_ref.skip_binder().self_ty();
             trace!(
                 "comparing type {} with kind {:?} against type {:?}",
                 impl_type,

src/tools/clippy/clippy_lints/src/derive.rs

@@ -251,7 +251,7 @@ fn check_hash_peq<'tcx>(
 
                 // Only care about `impl PartialEq<Foo> for Foo`
                 // For `impl PartialEq<B> for A, input_types is [A, B]
-                if trait_ref.substs.type_at(1) == ty {
+                if trait_ref.subst_identity().substs.type_at(1) == ty {
                     span_lint_and_then(
                         cx,
                         DERIVED_HASH_WITH_MANUAL_EQ,
@@ -299,7 +299,7 @@ fn check_ord_partial_ord<'tcx>(
 
                 // Only care about `impl PartialOrd<Foo> for Foo`
                 // For `impl PartialOrd<B> for A, input_types is [A, B]
-                if trait_ref.substs.type_at(1) == ty {
+                if trait_ref.subst_identity().substs.type_at(1) == ty {
                     let mess = if partial_ord_is_automatically_derived {
                         "you are implementing `Ord` explicitly but have derived `PartialOrd`"
                     } else {

src/tools/clippy/clippy_lints/src/fallible_impl_from.rs

@@ -56,7 +56,7 @@ impl<'tcx> LateLintPass<'tcx> for FallibleImplFrom {
         if_chain! {
             if let hir::ItemKind::Impl(impl_) = &item.kind;
             if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id);
-            if cx.tcx.is_diagnostic_item(sym::From, impl_trait_ref.def_id);
+            if cx.tcx.is_diagnostic_item(sym::From, impl_trait_ref.skip_binder().def_id);
             then {
                 lint_impl_body(cx, item.span, impl_.items);
             }

src/tools/clippy/clippy_lints/src/from_over_into.rs

@@ -76,7 +76,7 @@ impl<'tcx> LateLintPass<'tcx> for FromOverInto {
             && let Some(into_trait_seg) = hir_trait_ref.path.segments.last()
             // `impl Into<target_ty> for self_ty`
             && let Some(GenericArgs { args: [GenericArg::Type(target_ty)], .. }) = into_trait_seg.args
-            && let Some(middle_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)
+            && let Some(middle_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id).map(ty::EarlyBinder::subst_identity)
             && cx.tcx.is_diagnostic_item(sym::Into, middle_trait_ref.def_id)
             && !matches!(middle_trait_ref.substs.type_at(1).kind(), ty::Alias(ty::Opaque, _))
         {

src/tools/clippy/clippy_lints/src/missing_inline.rs

@@ -155,7 +155,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
         let container_id = assoc_item.container_id(cx.tcx);
         let trait_def_id = match assoc_item.container {
             TraitContainer => Some(container_id),
-            ImplContainer => cx.tcx.impl_trait_ref(container_id).map(|t| t.def_id),
+            ImplContainer => cx.tcx.impl_trait_ref(container_id).map(|t| t.skip_binder().def_id),
         };
 
         if let Some(trait_def_id) = trait_def_id {

src/tools/clippy/clippy_lints/src/non_send_fields_in_send_ty.rs

@@ -90,7 +90,7 @@ impl<'tcx> LateLintPass<'tcx> for NonSendFieldInSendTy {
             if send_trait == trait_id;
             if hir_impl.polarity == ImplPolarity::Positive;
             if let Some(ty_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id);
-            if let self_ty = ty_trait_ref.self_ty();
+            if let self_ty = ty_trait_ref.subst_identity().self_ty();
             if let ty::Adt(adt_def, impl_trait_substs) = self_ty.kind();
             then {
                 let mut non_send_fields = Vec::new();

src/tools/clippy/clippy_lints/src/only_used_in_recursion.rs

@@ -244,7 +244,7 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
             })) => {
                 #[allow(trivial_casts)]
                 if let Some(Node::Item(item)) = get_parent_node(cx.tcx, owner_id.into())
-                    && let Some(trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)
+                    && let Some(trait_ref) = cx.tcx.impl_trait_ref(item.owner_id).map(|t| t.subst_identity())
                     && let Some(trait_item_id) = cx.tcx.associated_item(owner_id).trait_item_def_id
                 {
                     (

src/tools/clippy/clippy_lints/src/use_self.rs

@@ -137,7 +137,7 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
             then {
                 // `self_ty` is the semantic self type of `impl <trait> for <type>`. This cannot be
                 // `Self`.
-                let self_ty = impl_trait_ref.self_ty();
+                let self_ty = impl_trait_ref.subst_identity().self_ty();
 
                 // `trait_method_sig` is the signature of the function, how it is declared in the
                 // trait, not in the impl of the trait.