diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index dd222485daf2c..b2db77944fd1e 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -7,9 +7,7 @@ use rustc_infer::infer::{DefiningAnchor, InferCtxt};
 use rustc_infer::traits::{Obligation, ObligationCause};
 use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts};
 use rustc_middle::ty::visit::TypeVisitable;
-use rustc_middle::ty::{
-    self, OpaqueHiddenType, OpaqueTypeKey, ToPredicate, Ty, TyCtxt, TypeFoldable,
-};
+use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable};
 use rustc_span::Span;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::ObligationCtxt;
@@ -256,8 +254,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         // Require the hidden type to be well-formed with only the generics of the opaque type.
         // Defining use functions may have more bounds than the opaque type, which is ok, as long as the
         // hidden type is well formed even without those bounds.
-        let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(definition_ty.into()))
-            .to_predicate(infcx.tcx);
+        let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(definition_ty.into()));
 
         let id_substs = InternalSubsts::identity_for_item(self.tcx, def_id.to_def_id());
 
@@ -282,6 +279,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         }
 
         ocx.register_obligation(Obligation::misc(
+            infcx.tcx,
             instantiated_ty.span,
             body_id,
             param_env,
diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
index a581726a15c9c..d0cf8622a4470 100644
--- a/compiler/rustc_borrowck/src/type_check/canonical.rs
+++ b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -92,8 +92,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 trait_ref,
                 constness: ty::BoundConstness::NotConst,
                 polarity: ty::ImplPolarity::Positive,
-            }))
-            .to_predicate(self.tcx()),
+            })),
             locations,
             category,
         );
@@ -122,14 +121,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
     pub(super) fn prove_predicates(
         &mut self,
-        predicates: impl IntoIterator<Item = impl ToPredicate<'tcx>>,
+        predicates: impl IntoIterator<
+            Item = impl ToPredicate<'tcx, ty::Predicate<'tcx>> + std::fmt::Debug,
+        >,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
     ) {
         for predicate in predicates {
-            let predicate = predicate.to_predicate(self.tcx());
-            debug!("prove_predicates(predicate={:?}, locations={:?})", predicate, locations,);
-
             self.prove_predicate(predicate, locations, category);
         }
     }
@@ -137,11 +135,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     #[instrument(skip(self), level = "debug")]
     pub(super) fn prove_predicate(
         &mut self,
-        predicate: ty::Predicate<'tcx>,
+        predicate: impl ToPredicate<'tcx, ty::Predicate<'tcx>> + std::fmt::Debug,
         locations: Locations,
         category: ConstraintCategory<'tcx>,
     ) {
         let param_env = self.param_env;
+        let predicate = predicate.to_predicate(self.tcx());
         self.fully_perform_op(
             locations,
             category,
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 6ccc29b09c0a5..7d36a63943c56 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -33,8 +33,7 @@ use rustc_middle::ty::subst::{SubstsRef, UserSubsts};
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
     self, Binder, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, Dynamic,
-    OpaqueHiddenType, OpaqueTypeKey, RegionVid, ToPredicate, Ty, TyCtxt, UserType,
-    UserTypeAnnotationIndex,
+    OpaqueHiddenType, OpaqueTypeKey, RegionVid, Ty, TyCtxt, UserType, UserTypeAnnotationIndex,
 };
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::{Span, DUMMY_SP};
@@ -1069,8 +1068,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     }
 
                     self.prove_predicate(
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(inferred_ty.into()))
-                            .to_predicate(self.tcx()),
+                        ty::Binder::dummy(ty::PredicateKind::WellFormed(inferred_ty.into())),
                         Locations::All(span),
                         ConstraintCategory::TypeAnnotation,
                     );
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index 5a8b3e30b9fc0..36956f5dd6d96 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -732,7 +732,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                         polarity: ty::ImplPolarity::Positive,
                     });
                     let obligation =
-                        Obligation::new(ObligationCause::dummy(), param_env, poly_trait_pred);
+                        Obligation::new(tcx, ObligationCause::dummy(), param_env, poly_trait_pred);
 
                     let implsrc = {
                         let infcx = tcx.infer_ctxt().build();
@@ -816,6 +816,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
                             if !nonconst_call_permission {
                                 let obligation = Obligation::new(
+                                    tcx,
                                     ObligationCause::dummy_with_span(*fn_span),
                                     param_env,
                                     tcx.mk_predicate(
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
index b28d70194917b..2d4afd0dc356b 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/ops.rs
@@ -147,6 +147,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
                 }
                 Adt(..) => {
                     let obligation = Obligation::new(
+                        tcx,
                         ObligationCause::dummy(),
                         param_env,
                         Binder::dummy(TraitPredicate {
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index d995d533ca3e4..6fd12985170e6 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -156,6 +156,7 @@ impl Qualif for NeedsNonConstDrop {
         let destruct = cx.tcx.require_lang_item(LangItem::Destruct, None);
 
         let obligation = Obligation::new(
+            cx.tcx,
             ObligationCause::dummy(),
             cx.param_env,
             ty::Binder::dummy(ty::TraitPredicate {
@@ -351,7 +352,11 @@ where
     // FIXME(valtrees): check whether const qualifs should behave the same
     // way for type and mir constants.
     let uneval = match constant.literal {
-        ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Param(_)) => None,
+        ConstantKind::Ty(ct)
+            if matches!(ct.kind(), ty::ConstKind::Param(_) | ty::ConstKind::Error(_)) =>
+        {
+            None
+        }
         ConstantKind::Ty(c) => bug!("expected ConstKind::Param here, found {:?}", c),
         ConstantKind::Unevaluated(uv, _) => Some(uv),
         ConstantKind::Val(..) => None,
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 0ba5e61510125..f76b282fa76d5 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -19,9 +19,7 @@ use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::util::{Discr, IntTypeExt};
-use rustc_middle::ty::{
-    self, ParamEnv, ToPredicate, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
-};
+use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable};
 use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS};
 use rustc_span::symbol::sym;
 use rustc_span::{self, Span};
@@ -464,9 +462,8 @@ fn check_opaque_meets_bounds<'tcx>(
     // Additionally require the hidden type to be well-formed with only the generics of the opaque type.
     // Defining use functions may have more bounds than the opaque type, which is ok, as long as the
     // hidden type is well formed even without those bounds.
-    let predicate =
-        ty::Binder::dummy(ty::PredicateKind::WellFormed(hidden_ty.into())).to_predicate(tcx);
-    ocx.register_obligation(Obligation::new(misc_cause, param_env, predicate));
+    let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(hidden_ty.into()));
+    ocx.register_obligation(Obligation::new(tcx, misc_cause, param_env, predicate));
 
     // Check that all obligations are satisfied by the implementation's
     // version.
diff --git a/compiler/rustc_hir_analysis/src/check/compare_method.rs b/compiler/rustc_hir_analysis/src/check/compare_method.rs
index 7c99896b45714..5a222031c5610 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_method.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_method.rs
@@ -238,7 +238,7 @@ fn compare_predicate_entailment<'tcx>(
                 kind: impl_m.kind,
             },
         );
-        ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate));
+        ocx.register_obligation(traits::Obligation::new(tcx, cause, param_env, predicate));
     }
 
     // We now need to check that the signature of the impl method is
@@ -521,7 +521,13 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
                 let num_trait_substs = trait_to_impl_substs.len();
                 let num_impl_substs = tcx.generics_of(impl_m.container_id(tcx)).params.len();
                 let ty = tcx.fold_regions(ty, |region, _| {
-                    let (ty::ReFree(_) | ty::ReEarlyBound(_)) = region.kind() else { return region; };
+                    match region.kind() {
+                        // Remap all free regions, which correspond to late-bound regions in the function.
+                        ty::ReFree(_) => {}
+                        // Remap early-bound regions as long as they don't come from the `impl` itself.
+                        ty::ReEarlyBound(ebr) if tcx.parent(ebr.def_id) != impl_m.container_id(tcx) => {}
+                        _ => return region,
+                    }
                     let Some(ty::ReEarlyBound(e)) = map.get(&region.into()).map(|r| r.expect_region().kind())
                     else {
                         tcx
@@ -605,6 +611,7 @@ impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> {
                 );
 
                 self.ocx.register_obligation(traits::Obligation::new(
+                    self.tcx(),
                     ObligationCause::new(
                         self.span,
                         self.body_id,
@@ -1579,7 +1586,7 @@ fn compare_type_predicate_entailment<'tcx>(
             },
         );
         ocx.register_obligations(obligations);
-        ocx.register_obligation(traits::Obligation::new(cause, param_env, predicate));
+        ocx.register_obligation(traits::Obligation::new(tcx, cause, param_env, predicate));
     }
 
     // Check that all obligations are satisfied by the implementation's
@@ -1784,7 +1791,7 @@ pub fn check_type_bounds<'tcx>(
         .subst_iter_copied(tcx, rebased_substs)
         .map(|(concrete_ty_bound, span)| {
             debug!("check_type_bounds: concrete_ty_bound = {:?}", concrete_ty_bound);
-            traits::Obligation::new(mk_cause(span), param_env, concrete_ty_bound)
+            traits::Obligation::new(tcx, mk_cause(span), param_env, concrete_ty_bound)
         })
         .collect();
     debug!("check_type_bounds: item_bounds={:?}", obligations);
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index efb34e4ff6592..1d7ceda725a39 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -14,8 +14,8 @@ use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{
-    self, AdtKind, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TyCtxt, TypeFoldable,
-    TypeSuperVisitable, TypeVisitable, TypeVisitor,
+    self, AdtKind, DefIdTree, GenericParamDefKind, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
+    TypeVisitable, TypeVisitor,
 };
 use rustc_middle::ty::{GenericArgKind, InternalSubsts};
 use rustc_session::parse::feature_err;
@@ -75,9 +75,10 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
         // for a type to be WF, we do not need to check if const trait predicates satisfy.
         let param_env = self.param_env.without_const();
         self.ocx.register_obligation(traits::Obligation::new(
+            self.tcx(),
             cause,
             param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(self.tcx()),
+            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
         ));
     }
 }
@@ -1111,12 +1112,12 @@ fn check_type_defn<'tcx>(tcx: TyCtxt<'tcx>, item: &hir::Item<'tcx>, all_sized: b
                     traits::MiscObligation,
                 );
                 wfcx.register_obligation(traits::Obligation::new(
+                    tcx,
                     cause,
                     wfcx.param_env,
                     ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(
                         ty::Const::from_anon_const(tcx, discr_def_id.expect_local()),
-                    ))
-                    .to_predicate(tcx),
+                    )),
                 ));
             }
         }
@@ -1453,7 +1454,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
                 wfcx.body_id,
                 traits::ItemObligation(def_id.to_def_id()),
             );
-            traits::Obligation::new(cause, wfcx.param_env, pred)
+            traits::Obligation::new(tcx, cause, wfcx.param_env, pred)
         });
 
     let predicates = predicates.0.instantiate_identity(tcx);
@@ -1783,8 +1784,7 @@ fn receiver_is_implemented<'tcx>(
         substs: tcx.mk_substs_trait(receiver_ty, &[]),
     });
 
-    let obligation =
-        traits::Obligation::new(cause, wfcx.param_env, trait_ref.without_const().to_predicate(tcx));
+    let obligation = traits::Obligation::new(tcx, cause, wfcx.param_env, trait_ref.without_const());
 
     if wfcx.infcx.predicate_must_hold_modulo_regions(&obligation) {
         true
@@ -1931,6 +1931,7 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
                 }
 
                 let obligation = traits::Obligation::new(
+                    tcx,
                     traits::ObligationCause::new(span, self.body_id, traits::TrivialBound),
                     empty_env,
                     pred,
diff --git a/compiler/rustc_hir_analysis/src/hir_wf_check.rs b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
index b0fdfcf38a608..4f9d5826583c3 100644
--- a/compiler/rustc_hir_analysis/src/hir_wf_check.rs
+++ b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
@@ -5,7 +5,7 @@ use rustc_hir::{ForeignItem, ForeignItemKind, HirId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::{ObligationCause, WellFormedLoc};
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::{self, Region, ToPredicate, TyCtxt, TypeFoldable, TypeFolder};
+use rustc_middle::ty::{self, Region, TyCtxt, TypeFoldable, TypeFolder};
 use rustc_trait_selection::traits;
 
 pub fn provide(providers: &mut Providers) {
@@ -74,10 +74,10 @@ fn diagnostic_hir_wf_check<'tcx>(
             let errors = traits::fully_solve_obligation(
                 &infcx,
                 traits::Obligation::new(
+                    self.tcx,
                     cause,
                     self.param_env,
-                    ty::Binder::dummy(ty::PredicateKind::WellFormed(tcx_ty.into()))
-                        .to_predicate(self.tcx),
+                    ty::Binder::dummy(ty::PredicateKind::WellFormed(tcx_ty.into())),
                 ),
             );
             if !errors.is_empty() {
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index 6a4a6a5b0a546..139f2e8413662 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -4,7 +4,7 @@ use rustc_errors::{Applicability, Diagnostic, MultiSpan};
 use rustc_hir::{self as hir, ExprKind};
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::traits::Obligation;
-use rustc_middle::ty::{self, ToPredicate, Ty};
+use rustc_middle::ty::{self, Ty};
 use rustc_span::Span;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::{
@@ -538,23 +538,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .bound_explicit_item_bounds(rpit_def_id)
                         .subst_iter_copied(self.tcx, substs)
                     {
-                        let pred = match pred.kind().skip_binder() {
+                        let pred = pred.kind().rebind(match pred.kind().skip_binder() {
                             ty::PredicateKind::Trait(mut trait_pred) => {
                                 assert_eq!(trait_pred.trait_ref.self_ty(), opaque_ty);
                                 trait_pred.trait_ref.substs =
                                     self.tcx.mk_substs_trait(ty, &trait_pred.trait_ref.substs[1..]);
-                                pred.kind().rebind(trait_pred).to_predicate(self.tcx)
+                                ty::PredicateKind::Trait(trait_pred)
                             }
                             ty::PredicateKind::Projection(mut proj_pred) => {
                                 assert_eq!(proj_pred.projection_ty.self_ty(), opaque_ty);
                                 proj_pred.projection_ty.substs = self
                                     .tcx
                                     .mk_substs_trait(ty, &proj_pred.projection_ty.substs[1..]);
-                                pred.kind().rebind(proj_pred).to_predicate(self.tcx)
+                                ty::PredicateKind::Projection(proj_pred)
                             }
                             _ => continue,
-                        };
+                        });
                         if !self.predicate_must_hold_modulo_regions(&Obligation::new(
+                            self.tcx,
                             ObligationCause::misc(span, self.body_id),
                             self.param_env,
                             pred,
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index ed2218b8746ee..302d512c71d13 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -380,6 +380,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         predicates.predicates.iter().zip(&predicates.spans)
                     {
                         let obligation = Obligation::new(
+                            self.tcx,
                             ObligationCause::dummy_with_span(callee_expr.span),
                             self.param_env,
                             *predicate,
diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs
index 1578cddd490e7..b9e90e47e508b 100644
--- a/compiler/rustc_hir_typeck/src/check.rs
+++ b/compiler/rustc_hir_typeck/src/check.rs
@@ -102,7 +102,7 @@ pub(super) fn check_fn<'a, 'tcx>(
 
     inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
 
-    if let ty::Dynamic(..) = declared_ret_ty.kind() {
+    if let ty::Dynamic(_, _, ty::Dyn) = declared_ret_ty.kind() {
         // FIXME: We need to verify that the return type is `Sized` after the return expression has
         // been evaluated so that we have types available for all the nodes being returned, but that
         // requires the coerced evaluated type to be stored. Moving `check_return_expr` before this
diff --git a/compiler/rustc_hir_typeck/src/coercion.rs b/compiler/rustc_hir_typeck/src/coercion.rs
index 71949b4211819..174b43313825e 100644
--- a/compiler/rustc_hir_typeck/src/coercion.rs
+++ b/compiler/rustc_hir_typeck/src/coercion.rs
@@ -55,7 +55,7 @@ use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::relate::RelateResult;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::visit::TypeVisitable;
-use rustc_middle::ty::{self, ToPredicate, Ty, TypeAndMut};
+use rustc_middle::ty::{self, Ty, TypeAndMut};
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::sym;
 use rustc_span::{self, BytePos, DesugaringKind, Span};
@@ -278,13 +278,13 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             for &source_ty in &[a, b] {
                 if source_ty != target_ty {
                     obligations.push(Obligation::new(
+                        self.tcx(),
                         self.cause.clone(),
                         self.param_env,
                         ty::Binder::dummy(ty::PredicateKind::Coerce(ty::CoercePredicate {
                             a: source_ty,
                             b: target_ty,
-                        }))
-                        .to_predicate(self.tcx()),
+                        })),
                     ));
                 }
             }
@@ -669,7 +669,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                     continue;
                 }
             };
-            match selcx.select(&obligation.with(trait_pred)) {
+            match selcx.select(&obligation.with(selcx.tcx(), trait_pred)) {
                 // Uncertain or unimplemented.
                 Ok(None) => {
                     if trait_pred.def_id() == unsize_did {
@@ -783,10 +783,11 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 // and then require that the resulting predicate (e.g., `usize: Clone`)
                 // holds (it does).
                 let predicate = predicate.with_self_ty(self.tcx, a);
-                Obligation::new(self.cause.clone(), self.param_env, predicate)
+                Obligation::new(self.tcx, self.cause.clone(), self.param_env, predicate)
             })
             // Enforce the region bound (e.g., `usize: 'static`, in our example).
             .chain([Obligation::new(
+                self.tcx,
                 self.cause.clone(),
                 self.param_env,
                 self.tcx.mk_predicate(ty::Binder::dummy(ty::PredicateKind::TypeOutlives(
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index 97d05b4f95c4c..c826a886ca641 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -22,8 +22,7 @@ use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
-    self, AdtKind, CanonicalUserType, DefIdTree, EarlyBinder, GenericParamDefKind, ToPredicate, Ty,
-    UserType,
+    self, AdtKind, CanonicalUserType, DefIdTree, EarlyBinder, GenericParamDefKind, Ty, UserType,
 };
 use rustc_middle::ty::{GenericArgKind, InternalSubsts, SubstsRef, UserSelfTy, UserSubsts};
 use rustc_session::lint;
@@ -559,9 +558,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // WF obligations never themselves fail, so no real need to give a detailed cause:
         let cause = traits::ObligationCause::new(span, self.body_id, code);
         self.register_predicate(traits::Obligation::new(
+            self.tcx,
             cause,
             self.param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(self.tcx),
+            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
         ));
     }
 
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 8cf70eb5431a8..c3833b4872d99 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -73,7 +73,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let ty = self.typeck_results.borrow().expr_ty_adjusted(expr);
                 let ty = self.resolve_vars_if_possible(ty);
                 if ty.has_non_region_infer() {
-                    assert!(self.is_tainted_by_errors());
                     self.tcx.ty_error()
                 } else {
                     self.tcx.erase_regions(ty)
@@ -2150,6 +2149,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             ),
                         );
                         let obligation = traits::Obligation::new(
+                            self.tcx,
                             traits::ObligationCause::dummy(),
                             self.param_env,
                             ty::Binder::dummy(ty::TraitPredicate {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 06e6e4350fcbc..316ecb0ed52e4 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -1090,14 +1090,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         if let Some(into_def_id) = self.tcx.get_diagnostic_item(sym::Into)
             && self.predicate_must_hold_modulo_regions(&traits::Obligation::new(
+                self.tcx,
                 self.misc(expr.span),
                 self.param_env,
                 ty::Binder::dummy(ty::TraitRef {
                     def_id: into_def_id,
                     substs: self.tcx.mk_substs_trait(expr_ty, &[expected_ty.into()]),
                 })
-                .to_poly_trait_predicate()
-                .to_predicate(self.tcx),
+                .to_poly_trait_predicate(),
             ))
         {
             let sugg = if expr.precedence().order() >= PREC_POSTFIX {
diff --git a/compiler/rustc_hir_typeck/src/method/mod.rs b/compiler/rustc_hir_typeck/src/method/mod.rs
index 3f390cba3e7c2..37336edd1fda5 100644
--- a/compiler/rustc_hir_typeck/src/method/mod.rs
+++ b/compiler/rustc_hir_typeck/src/method/mod.rs
@@ -20,7 +20,7 @@ use rustc_hir::def_id::DefId;
 use rustc_infer::infer::{self, InferOk};
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
-use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TypeVisitable};
+use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, Ty, TypeVisitable};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
@@ -293,10 +293,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let poly_trait_ref = ty::Binder::dummy(trait_ref);
         (
             traits::Obligation::misc(
+                self.tcx,
                 span,
                 self.body_id,
                 self.param_env,
-                poly_trait_ref.without_const().to_predicate(self.tcx),
+                poly_trait_ref.without_const(),
             ),
             substs,
         )
@@ -335,6 +336,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         (
             traits::Obligation::new(
+                self.tcx,
                 traits::ObligationCause::new(
                     span,
                     self.body_id,
@@ -346,7 +348,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     },
                 ),
                 self.param_env,
-                poly_trait_ref.without_const().to_predicate(self.tcx),
+                poly_trait_ref.without_const(),
             ),
             substs,
         )
@@ -523,9 +525,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             method_ty, obligation
         );
         obligations.push(traits::Obligation::new(
+            tcx,
             cause,
             self.param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(method_ty.into())).to_predicate(tcx),
+            ty::Binder::dummy(ty::PredicateKind::WellFormed(method_ty.into())),
         ));
 
         let callee = MethodCallee { def_id, substs, sig: fn_sig };
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 46a760851893d..9d75ccad133dd 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -19,7 +19,8 @@ use rustc_middle::middle::stability;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::AssocItem;
 use rustc_middle::ty::GenericParamDefKind;
-use rustc_middle::ty::{self, ParamEnvAnd, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeVisitable};
+use rustc_middle::ty::ToPredicate;
+use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeFoldable, TypeVisitable};
 use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_session::lint;
 use rustc_span::def_id::DefId;
@@ -1429,7 +1430,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     ) -> traits::SelectionResult<'tcx, traits::Selection<'tcx>> {
         let cause = traits::ObligationCause::misc(self.span, self.body_id);
         let predicate = ty::Binder::dummy(trait_ref).to_poly_trait_predicate();
-        let obligation = traits::Obligation::new(cause, self.param_env, predicate);
+        let obligation = traits::Obligation::new(self.tcx, cause, self.param_env, predicate);
         traits::SelectionContext::new(self).select(&obligation)
     }
 
@@ -1560,7 +1561,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let predicate =
                         ty::Binder::dummy(trait_ref).without_const().to_predicate(self.tcx);
                     parent_pred = Some(predicate);
-                    let obligation = traits::Obligation::new(cause, self.param_env, predicate);
+                    let obligation =
+                        traits::Obligation::new(self.tcx, cause, self.param_env, predicate);
                     if !self.predicate_may_hold(&obligation) {
                         result = ProbeResult::NoMatch;
                         if self.probe(|_| {
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index 19f56c738239b..e2c5edd0e8833 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -23,7 +23,7 @@ use rustc_middle::traits::util::supertraits;
 use rustc_middle::ty::fast_reject::DeepRejectCtxt;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::print::with_crate_prefix;
-use rustc_middle::ty::{self, DefIdTree, GenericArgKind, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, DefIdTree, GenericArgKind, Ty, TyCtxt, TypeVisitable};
 use rustc_middle::ty::{IsSuggestable, ToPolyTraitRef};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Symbol;
@@ -80,10 +80,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         let trait_ref = ty::TraitRef::new(fn_once, fn_once_substs);
                         let poly_trait_ref = ty::Binder::dummy(trait_ref);
                         let obligation = Obligation::misc(
+                            tcx,
                             span,
                             self.body_id,
                             self.param_env,
-                            poly_trait_ref.without_const().to_predicate(tcx),
+                            poly_trait_ref.without_const(),
                         );
                         self.predicate_may_hold(&obligation)
                     })
diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs
index a299a3e578d22..34f54328230f4 100644
--- a/compiler/rustc_infer/src/infer/canonical/query_response.rs
+++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs
@@ -581,9 +581,9 @@ impl<'tcx> InferCtxt<'tcx> {
                 span_bug!(cause.span, "unexpected const outlives {:?}", predicate);
             }
         };
-        let predicate = predicate.0.rebind(atom).to_predicate(self.tcx);
+        let predicate = predicate.0.rebind(atom);
 
-        Obligation::new(cause, param_env, predicate)
+        Obligation::new(self.tcx, cause, param_env, predicate)
     }
 
     /// Given two sets of values for the same set of canonical variables, unify them.
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/combine.rs
index a973bf54b055e..37f071a19acd6 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/combine.rs
@@ -37,7 +37,7 @@ use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::relate::{self, Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, InferConst, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, InferConst, Ty, TyCtxt, TypeVisitable};
 use rustc_middle::ty::{IntType, UintType};
 use rustc_span::{Span, DUMMY_SP};
 
@@ -347,10 +347,10 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
 
         if needs_wf {
             self.obligations.push(Obligation::new(
+                self.tcx(),
                 self.trace.cause.clone(),
                 self.param_env,
-                ty::Binder::dummy(ty::PredicateKind::WellFormed(b_ty.into()))
-                    .to_predicate(self.infcx.tcx),
+                ty::Binder::dummy(ty::PredicateKind::WellFormed(b_ty.into())),
             ));
         }
 
@@ -444,9 +444,10 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
             ty::PredicateKind::ConstEquate(b, a)
         };
         self.obligations.push(Obligation::new(
+            self.tcx(),
             self.trace.cause.clone(),
             self.param_env,
-            ty::Binder::dummy(predicate).to_predicate(self.tcx()),
+            ty::Binder::dummy(predicate),
         ));
     }
 }
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs
index a982f11f7187f..1fa95f8d62ab9 100644
--- a/compiler/rustc_infer/src/infer/opaque_types.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types.rs
@@ -595,7 +595,12 @@ impl<'tcx> InferCtxt<'tcx> {
             }
             // Require that the predicate holds for the concrete type.
             debug!(?predicate);
-            obligations.push(traits::Obligation::new(cause.clone(), param_env, predicate));
+            obligations.push(traits::Obligation::new(
+                self.tcx,
+                cause.clone(),
+                param_env,
+                predicate,
+            ));
         }
         Ok(InferOk { value: (), obligations })
     }
diff --git a/compiler/rustc_infer/src/infer/projection.rs b/compiler/rustc_infer/src/infer/projection.rs
index 9f12bc972a816..eb6deee291cf7 100644
--- a/compiler/rustc_infer/src/infer/projection.rs
+++ b/compiler/rustc_infer/src/infer/projection.rs
@@ -1,5 +1,5 @@
 use rustc_middle::traits::ObligationCause;
-use rustc_middle::ty::{self, ToPredicate, Ty};
+use rustc_middle::ty::{self, Ty};
 
 use crate::traits::{Obligation, PredicateObligation};
 
@@ -28,12 +28,8 @@ impl<'tcx> InferCtxt<'tcx> {
         });
         let projection =
             ty::Binder::dummy(ty::ProjectionPredicate { projection_ty, term: ty_var.into() });
-        let obligation = Obligation::with_depth(
-            cause,
-            recursion_depth,
-            param_env,
-            projection.to_predicate(self.tcx),
-        );
+        let obligation =
+            Obligation::with_depth(self.tcx, cause, recursion_depth, param_env, projection);
         obligations.push(obligation);
         ty_var
     }
diff --git a/compiler/rustc_infer/src/infer/sub.rs b/compiler/rustc_infer/src/infer/sub.rs
index 97354ba5d1bd1..8c8445a4d9eb8 100644
--- a/compiler/rustc_infer/src/infer/sub.rs
+++ b/compiler/rustc_infer/src/infer/sub.rs
@@ -6,7 +6,7 @@ use crate::traits::Obligation;
 use rustc_middle::ty::relate::{Cause, Relate, RelateResult, TypeRelation};
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::TyVar;
-use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use std::mem;
 
 /// Ensures `a` is made a subtype of `b`. Returns `a` on success.
@@ -95,14 +95,14 @@ impl<'tcx> TypeRelation<'tcx> for Sub<'_, '_, 'tcx> {
                 // can't make progress on `A <: B` if both A and B are
                 // type variables, so record an obligation.
                 self.fields.obligations.push(Obligation::new(
+                    self.tcx(),
                     self.fields.trace.cause.clone(),
                     self.fields.param_env,
                     ty::Binder::dummy(ty::PredicateKind::Subtype(ty::SubtypePredicate {
                         a_is_expected: self.a_is_expected,
                         a,
                         b,
-                    }))
-                    .to_predicate(self.tcx()),
+                    })),
                 ));
 
                 Ok(a)
diff --git a/compiler/rustc_infer/src/traits/mod.rs b/compiler/rustc_infer/src/traits/mod.rs
index c8600ded987e5..a9e6241bf6b51 100644
--- a/compiler/rustc_infer/src/traits/mod.rs
+++ b/compiler/rustc_infer/src/traits/mod.rs
@@ -10,7 +10,7 @@ pub mod util;
 
 use rustc_hir as hir;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
-use rustc_middle::ty::{self, Const, Ty, TyCtxt};
+use rustc_middle::ty::{self, Const, ToPredicate, Ty, TyCtxt};
 use rustc_span::Span;
 
 pub use self::FulfillmentErrorCode::*;
@@ -124,38 +124,41 @@ pub enum FulfillmentErrorCode<'tcx> {
 
 impl<'tcx, O> Obligation<'tcx, O> {
     pub fn new(
+        tcx: TyCtxt<'tcx>,
         cause: ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
-        predicate: O,
+        predicate: impl ToPredicate<'tcx, O>,
     ) -> Obligation<'tcx, O> {
-        Obligation { cause, param_env, recursion_depth: 0, predicate }
+        Self::with_depth(tcx, cause, 0, param_env, predicate)
     }
 
     pub fn with_depth(
+        tcx: TyCtxt<'tcx>,
         cause: ObligationCause<'tcx>,
         recursion_depth: usize,
         param_env: ty::ParamEnv<'tcx>,
-        predicate: O,
+        predicate: impl ToPredicate<'tcx, O>,
     ) -> Obligation<'tcx, O> {
+        let predicate = predicate.to_predicate(tcx);
         Obligation { cause, param_env, recursion_depth, predicate }
     }
 
     pub fn misc(
+        tcx: TyCtxt<'tcx>,
         span: Span,
         body_id: hir::HirId,
         param_env: ty::ParamEnv<'tcx>,
-        trait_ref: O,
+        trait_ref: impl ToPredicate<'tcx, O>,
     ) -> Obligation<'tcx, O> {
-        Obligation::new(ObligationCause::misc(span, body_id), param_env, trait_ref)
+        Obligation::new(tcx, ObligationCause::misc(span, body_id), param_env, trait_ref)
     }
 
-    pub fn with<P>(&self, value: P) -> Obligation<'tcx, P> {
-        Obligation {
-            cause: self.cause.clone(),
-            param_env: self.param_env,
-            recursion_depth: self.recursion_depth,
-            predicate: value,
-        }
+    pub fn with<P>(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        value: impl ToPredicate<'tcx, P>,
+    ) -> Obligation<'tcx, P> {
+        Obligation::with_depth(tcx, self.cause.clone(), self.recursion_depth, self.param_env, value)
     }
 }
 
diff --git a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
index 619582c0539b8..7e0a8a0df16c0 100644
--- a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
+++ b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
@@ -108,6 +108,7 @@ impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound {
                 // then we must've taken advantage of the hack in `project_and_unify_types` where
                 // we replace opaques with inference vars. Emit a warning!
                 if !infcx.predicate_must_hold_modulo_regions(&traits::Obligation::new(
+                    cx.tcx,
                     traits::ObligationCause::dummy(),
                     cx.param_env,
                     assoc_pred,
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index ff0fb9bae9232..9ae34013ecb8a 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -533,16 +533,14 @@ trait UnusedDelimLint {
         right_pos: Option<BytePos>,
     ) {
         let spans = match value.kind {
-            ast::ExprKind::Block(ref block, None) if block.stmts.len() > 0 => {
-                let start = block.stmts[0].span;
-                let end = block.stmts[block.stmts.len() - 1].span;
-                if let Some(start) = start.find_ancestor_inside(value.span)
-                    && let Some(end) = end.find_ancestor_inside(value.span)
+            ast::ExprKind::Block(ref block, None) if block.stmts.len() == 1 => {
+                if let StmtKind::Expr(expr) = &block.stmts[0].kind
+                    && let ExprKind::Err = expr.kind
                 {
-                    Some((
-                        value.span.with_hi(start.lo()),
-                        value.span.with_lo(end.hi()),
-                    ))
+                    return
+                }
+                if let Some(span) = block.stmts[0].span.find_ancestor_inside(value.span) {
+                    Some((value.span.with_hi(span.lo()), value.span.with_lo(span.hi())))
                 } else {
                     None
                 }
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 18eb06b83c9df..f9a762261e2ce 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1125,42 +1125,42 @@ impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
     }
 }
 
-pub trait ToPredicate<'tcx> {
-    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx>;
+pub trait ToPredicate<'tcx, Predicate> {
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate;
 }
 
-impl<'tcx> ToPredicate<'tcx> for Predicate<'tcx> {
-    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+impl<'tcx, T> ToPredicate<'tcx, T> for T {
+    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T {
         self
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
+impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for Binder<'tcx, PredicateKind<'tcx>> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         tcx.mk_predicate(self)
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
+impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTraitPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(PredicateKind::Trait).to_predicate(tcx)
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
+impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyRegionOutlivesPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(PredicateKind::RegionOutlives).to_predicate(tcx)
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
+impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyTypeOutlivesPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(PredicateKind::TypeOutlives).to_predicate(tcx)
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
+impl<'tcx> ToPredicate<'tcx, Predicate<'tcx>> for PolyProjectionPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(PredicateKind::Projection).to_predicate(tcx)
     }
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index a56450a3573d1..02848bcffb298 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -893,6 +893,7 @@ symbols! {
         masked,
         match_beginning_vert,
         match_default_bindings,
+        matches_macro,
         maxnumf32,
         maxnumf64,
         may_dangle,
diff --git a/compiler/rustc_trait_selection/src/autoderef.rs b/compiler/rustc_trait_selection/src/autoderef.rs
index 54c738d838975..b7240a8289730 100644
--- a/compiler/rustc_trait_selection/src/autoderef.rs
+++ b/compiler/rustc_trait_selection/src/autoderef.rs
@@ -3,8 +3,8 @@ use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{self, TraitEngine, TraitEngineExt};
 use rustc_hir as hir;
 use rustc_infer::infer::InferCtxt;
+use rustc_middle::ty::TypeVisitable;
 use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt};
-use rustc_middle::ty::{ToPredicate, TypeVisitable};
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
 use rustc_span::Span;
@@ -130,9 +130,10 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
         let cause = traits::ObligationCause::misc(self.span, self.body_id);
 
         let obligation = traits::Obligation::new(
+            tcx,
             cause.clone(),
             self.param_env,
-            ty::Binder::dummy(trait_ref).without_const().to_predicate(tcx),
+            ty::Binder::dummy(trait_ref).without_const(),
         );
         if !self.infcx.predicate_may_hold(&obligation) {
             debug!("overloaded_deref_ty: cannot match obligation");
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 188f8bb7e2a58..5869bc76b596c 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -96,8 +96,12 @@ impl<'tcx> AutoTraitFinder<'tcx> {
             PolyTraitRef::to_poly_trait_predicate,
             PolyTraitRef::to_poly_trait_predicate_negative_polarity,
         ] {
-            let result =
-                selcx.select(&Obligation::new(ObligationCause::dummy(), orig_env, f(&trait_pred)));
+            let result = selcx.select(&Obligation::new(
+                tcx,
+                ObligationCause::dummy(),
+                orig_env,
+                f(&trait_pred),
+            ));
             if let Ok(Some(ImplSource::UserDefined(_))) = result {
                 debug!(
                     "find_auto_trait_generics({:?}): \
@@ -280,8 +284,12 @@ impl<'tcx> AutoTraitFinder<'tcx> {
 
             // Call `infcx.resolve_vars_if_possible` to see if we can
             // get rid of any inference variables.
-            let obligation =
-                infcx.resolve_vars_if_possible(Obligation::new(dummy_cause.clone(), new_env, pred));
+            let obligation = infcx.resolve_vars_if_possible(Obligation::new(
+                tcx,
+                dummy_cause.clone(),
+                new_env,
+                pred,
+            ));
             let result = select.select(&obligation);
 
             match result {
@@ -706,7 +714,10 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                     // and turn them into an explicit negative impl for our type.
                     debug!("Projecting and unifying projection predicate {:?}", predicate);
 
-                    match project::poly_project_and_unify_type(select, &obligation.with(p)) {
+                    match project::poly_project_and_unify_type(
+                        select,
+                        &obligation.with(self.tcx, p),
+                    ) {
                         ProjectAndUnifyResult::MismatchedProjectionTypes(e) => {
                             debug!(
                                 "evaluate_nested_obligations: Unable to unify predicate \
diff --git a/compiler/rustc_trait_selection/src/traits/codegen.rs b/compiler/rustc_trait_selection/src/traits/codegen.rs
index 8a62bf015674a..ca4299f7db394 100644
--- a/compiler/rustc_trait_selection/src/traits/codegen.rs
+++ b/compiler/rustc_trait_selection/src/traits/codegen.rs
@@ -40,7 +40,7 @@ pub fn codegen_select_candidate<'tcx>(
 
     let obligation_cause = ObligationCause::dummy();
     let obligation =
-        Obligation::new(obligation_cause, param_env, trait_ref.to_poly_trait_predicate());
+        Obligation::new(tcx, obligation_cause, param_env, trait_ref.to_poly_trait_predicate());
 
     let selection = match selcx.select(&obligation) {
         Ok(Some(selection)) => selection,
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
index 58da54afb75b9..6a5744f5f762b 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
@@ -32,7 +32,7 @@ pub fn recompute_applicable_impls<'tcx>(
             impl_predicates
                 .predicates
                 .iter()
-                .map(|&predicate| Obligation::new(dummy_cause.clone(), param_env, predicate)),
+                .map(|&predicate| Obligation::new(tcx, dummy_cause.clone(), param_env, predicate)),
         );
 
         ocx.select_where_possible().is_empty()
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 786cadaa6cefc..f087afa20baca 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -344,14 +344,14 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
                 });
                 let substs = self.tcx.mk_substs_trait(ty.skip_binder(), &[var.into()]);
                 let obligation = Obligation::new(
+                    self.tcx,
                     ObligationCause::dummy(),
                     param_env,
                     ty.rebind(ty::TraitPredicate {
                         trait_ref: ty::TraitRef::new(trait_def_id, substs),
                         constness,
                         polarity,
-                    })
-                    .to_predicate(self.tcx),
+                    }),
                 );
                 let mut fulfill_cx = <dyn TraitEngine<'tcx>>::new_in_snapshot(self.tcx);
                 fulfill_cx.register_predicate_obligation(self, obligation);
@@ -984,7 +984,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 );
                                 trait_pred
                             });
-                            let unit_obligation = obligation.with(predicate.to_predicate(tcx));
+                            let unit_obligation = obligation.with(tcx, predicate);
                             if self.predicate_may_hold(&unit_obligation) {
                                 err.note(
                                     "this error might have been caused by changes to \
@@ -2012,7 +2012,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             ..*tr
         });
 
-        Obligation::new(ObligationCause::dummy(), param_env, trait_pred.to_predicate(self.tcx))
+        Obligation::new(self.tcx, ObligationCause::dummy(), param_env, trait_pred)
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -2100,11 +2100,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     )
                 };
 
-                let obligation = Obligation::new(
-                    obligation.cause.clone(),
-                    obligation.param_env,
-                    trait_ref.to_poly_trait_predicate(),
-                );
+                let obligation = obligation.with(self.tcx, trait_ref.to_poly_trait_predicate());
                 let mut selcx = SelectionContext::with_query_mode(
                     &self,
                     crate::traits::TraitQueryMode::Standard,
@@ -2534,11 +2530,8 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             )
             .value;
 
-            let obligation = Obligation::new(
-                ObligationCause::dummy(),
-                param_env,
-                cleaned_pred.to_predicate(selcx.tcx()),
-            );
+            let obligation =
+                Obligation::new(self.tcx, ObligationCause::dummy(), param_env, cleaned_pred);
 
             self.predicate_may_hold(&obligation)
         })
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 84daaf97ecfa8..b8609077036f4 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -301,7 +301,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         obligated_types: &mut Vec<Ty<'tcx>>,
         seen_requirements: &mut FxHashSet<DefId>,
     ) where
-        T: fmt::Display;
+        T: fmt::Display + ToPredicate<'tcx, T>;
 
     /// Suggest to await before try: future? => future.await?
     fn suggest_await_before_try(
@@ -334,7 +334,7 @@ pub trait TypeErrCtxtExt<'tcx> {
     );
 }
 
-fn predicate_constraint(generics: &hir::Generics<'_>, pred: String) -> (Span, String) {
+fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) -> (Span, String) {
     (
         generics.tail_span_for_predicate_suggestion(),
         format!("{} {}", generics.add_where_or_trailing_comma(), pred),
@@ -416,7 +416,7 @@ fn suggest_restriction<'tcx>(
             },
             // `fn foo(t: impl Trait)`
             //                       ^ suggest `where <T as Trait>::A: Bound`
-            predicate_constraint(hir_generics, trait_pred.to_predicate(tcx).to_string()),
+            predicate_constraint(hir_generics, trait_pred.to_predicate(tcx)),
         ];
         sugg.extend(ty_spans.into_iter().map(|s| (s, type_param_name.to_string())));
 
@@ -440,9 +440,7 @@ fn suggest_restriction<'tcx>(
                 .find(|p| !matches!(p.kind, hir::GenericParamKind::Type { synthetic: true, .. })),
             super_traits,
         ) {
-            (_, None) => {
-                predicate_constraint(hir_generics, trait_pred.to_predicate(tcx).to_string())
-            }
+            (_, None) => predicate_constraint(hir_generics, trait_pred.to_predicate(tcx)),
             (None, Some((ident, []))) => (
                 ident.span.shrink_to_hi(),
                 format!(": {}", trait_pred.print_modifiers_and_trait_path()),
@@ -1162,7 +1160,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         for predicate in predicates.iter() {
             if !self.predicate_must_hold_modulo_regions(
-                &obligation.with(predicate.with_self_ty(self.tcx, self_ref_ty)),
+                &obligation.with(self.tcx, predicate.with_self_ty(self.tcx, self_ref_ty)),
             ) {
                 return;
             }
@@ -1523,7 +1521,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         let self_ty_satisfies_dyn_predicates = |self_ty| {
                             predicates.iter().all(|predicate| {
                                 let pred = predicate.with_self_ty(self.tcx, self_ty);
-                                let obl = Obligation::new(cause.clone(), param_env, pred);
+                                let obl = Obligation::new(self.tcx, cause.clone(), param_env, pred);
                                 self.predicate_may_hold(&obl)
                             })
                         };
@@ -2704,7 +2702,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
                 obligated_types.push(ty);
 
-                let parent_predicate = parent_trait_ref.to_predicate(tcx);
+                let parent_predicate = parent_trait_ref;
                 if !self.is_recursive_obligation(obligated_types, &data.parent_code) {
                     // #74711: avoid a stack overflow
                     ensure_sufficient_stack(|| {
@@ -2766,7 +2764,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     _ => err.note(&msg),
                 };
 
-                let mut parent_predicate = parent_trait_pred.to_predicate(tcx);
+                let mut parent_predicate = parent_trait_pred;
                 let mut data = &data.derived;
                 let mut count = 0;
                 seen_requirements.insert(parent_def_id);
@@ -2826,7 +2824,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             ObligationCauseCode::DerivedObligation(ref data) => {
                 let parent_trait_ref = self.resolve_vars_if_possible(data.parent_trait_pred);
-                let parent_predicate = parent_trait_ref.to_predicate(tcx);
+                let parent_predicate = parent_trait_ref;
                 // #74711: avoid a stack overflow
                 ensure_sufficient_stack(|| {
                     self.note_obligation_cause_code(
@@ -3070,9 +3068,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         ..*tr
                     });
                     let field_obl = Obligation::new(
+                        self.tcx,
                         obligation.cause.clone(),
                         obligation.param_env,
-                        trait_pred.to_predicate(self.tcx),
+                        trait_pred,
                     );
                     self.predicate_must_hold_modulo_regions(&field_obl)
                 })
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index 4905bb69cc5ca..d84f768cce4d7 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -9,7 +9,6 @@ use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::{self, Binder, Const, Ty, TypeVisitable};
 use std::marker::PhantomData;
 
@@ -296,7 +295,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 &mut obligations,
             );
             if predicate != obligation.predicate {
-                obligations.push(obligation.with(predicate));
+                obligations.push(obligation.with(infcx.tcx, predicate));
                 return ProcessResult::Changed(mk_pending(obligations));
             }
         }
@@ -307,7 +306,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 // This means we need to pass it the bound version of our
                 // predicate.
                 ty::PredicateKind::Trait(trait_ref) => {
-                    let trait_obligation = obligation.with(binder.rebind(trait_ref));
+                    let trait_obligation = obligation.with(infcx.tcx, binder.rebind(trait_ref));
 
                     self.process_trait_obligation(
                         obligation,
@@ -316,7 +315,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     )
                 }
                 ty::PredicateKind::Projection(data) => {
-                    let project_obligation = obligation.with(binder.rebind(data));
+                    let project_obligation = obligation.with(infcx.tcx, binder.rebind(data));
 
                     self.process_projection_obligation(
                         obligation,
@@ -335,9 +334,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 | ty::PredicateKind::ConstEquate(..) => {
                     let pred =
                         ty::Binder::dummy(infcx.replace_bound_vars_with_placeholders(binder));
-                    ProcessResult::Changed(mk_pending(vec![
-                        obligation.with(pred.to_predicate(self.selcx.tcx())),
-                    ]))
+                    ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)]))
                 }
                 ty::PredicateKind::TypeWellFormedFromEnv(..) => {
                     bug!("TypeWellFormedFromEnv is only used for Chalk")
@@ -345,7 +342,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
             },
             Some(pred) => match pred {
                 ty::PredicateKind::Trait(data) => {
-                    let trait_obligation = obligation.with(Binder::dummy(data));
+                    let trait_obligation = obligation.with(infcx.tcx, Binder::dummy(data));
 
                     self.process_trait_obligation(
                         obligation,
@@ -370,7 +367,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 }
 
                 ty::PredicateKind::Projection(ref data) => {
-                    let project_obligation = obligation.with(Binder::dummy(*data));
+                    let project_obligation = obligation.with(infcx.tcx, Binder::dummy(*data));
 
                     self.process_projection_obligation(
                         obligation,
@@ -697,7 +694,7 @@ impl<'a, 'tcx> FulfillProcessor<'a, 'tcx> {
             }
             // Let the caller handle the recursion
             ProjectAndUnifyResult::Recursive => ProcessResult::Changed(mk_pending(vec![
-                project_obligation.with(project_obligation.predicate.to_predicate(tcx)),
+                project_obligation.with(tcx, project_obligation.predicate),
             ])),
             ProjectAndUnifyResult::MismatchedProjectionTypes(e) => {
                 ProcessResult::Error(CodeProjectionError(e))
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 10e48610e3abb..ddc9b768f07e0 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -440,7 +440,7 @@ pub fn impossible_predicates<'tcx>(
     let ocx = ObligationCtxt::new(&infcx);
     let predicates = ocx.normalize(ObligationCause::dummy(), param_env, predicates);
     for predicate in predicates {
-        let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate);
+        let obligation = Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate);
         ocx.register_obligation(obligation);
     }
     let errors = ocx.select_all_or_error();
@@ -530,6 +530,7 @@ fn is_impossible_method<'tcx>(
     let predicates_for_trait = predicates.predicates.iter().filter_map(|(pred, span)| {
         if pred.visit_with(&mut visitor).is_continue() {
             Some(Obligation::new(
+                tcx,
                 ObligationCause::dummy_with_span(*span),
                 param_env,
                 ty::EarlyBinder(*pred).subst(tcx, impl_trait_ref.substs),
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 0bb25a74dc8b0..eaca3eaef0c1f 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -723,10 +723,9 @@ fn receiver_is_dispatchable<'tcx>(
             def_id: dispatch_from_dyn_did,
             substs: tcx.mk_substs_trait(receiver_ty, &[unsized_receiver_ty.into()]),
         })
-        .without_const()
-        .to_predicate(tcx);
+        .without_const();
 
-        Obligation::new(ObligationCause::dummy(), param_env, predicate)
+        Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate)
     };
 
     let infcx = tcx.infer_ctxt().build();
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 572f82117cc0e..ede6cd607b7fe 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -200,7 +200,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>(
             infcx.replace_bound_vars_with_placeholders(obligation.predicate);
         let new_universe = infcx.universe();
 
-        let placeholder_obligation = obligation.with(placeholder_predicate);
+        let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate);
         match project_and_unify_type(selcx, &placeholder_obligation) {
             ProjectAndUnifyResult::MismatchedProjectionTypes(e) => Err(e),
             ProjectAndUnifyResult::Holds(obligations)
@@ -517,6 +517,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
                         let recursion_limit = self.tcx().recursion_limit();
                         if !recursion_limit.value_within_limit(self.depth) {
                             let obligation = Obligation::with_depth(
+                                self.tcx(),
                                 self.cause.clone(),
                                 recursion_limit.0,
                                 self.param_env,
@@ -573,6 +574,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
                     && !self.tcx().sess.opts.actually_rustdoc
                 {
                     let obligation = Obligation::with_depth(
+                        self.selcx.tcx(),
                         self.cause.clone(),
                         recursion_limit.0,
                         self.param_env,
@@ -1110,7 +1112,8 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>(
         }
     }
 
-    let obligation = Obligation::with_depth(cause.clone(), depth, param_env, projection_ty);
+    let obligation =
+        Obligation::with_depth(selcx.tcx(), cause.clone(), depth, param_env, projection_ty);
 
     match project(selcx, &obligation) {
         Ok(Projected::Progress(Progress {
@@ -1343,8 +1346,8 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
             ty::Binder::dummy(ty::TraitRef { def_id: trait_def_id, substs: trait_substs })
                 .to_poly_trait_predicate();
 
-        let _ =
-            selcx.infcx().commit_if_ok(|_| match selcx.select(&obligation.with(trait_predicate)) {
+        let _ = selcx.infcx().commit_if_ok(|_| {
+            match selcx.select(&obligation.with(tcx, trait_predicate)) {
                 Ok(Some(super::ImplSource::UserDefined(data))) => {
                     candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(
                         ImplTraitInTraitCandidate::Impl(data),
@@ -1364,7 +1367,8 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
                     candidate_set.mark_error(e);
                     return Err(());
                 }
-            });
+            }
+        });
     }
 }
 
@@ -1538,7 +1542,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
     // If we are resolving `<T as TraitRef<...>>::Item == Type`,
     // start out by selecting the predicate `T as TraitRef<...>`:
     let poly_trait_ref = ty::Binder::dummy(obligation.predicate.trait_ref(selcx.tcx()));
-    let trait_obligation = obligation.with(poly_trait_ref.to_poly_trait_predicate());
+    let trait_obligation = obligation.with(selcx.tcx(), poly_trait_ref.to_poly_trait_predicate());
     let _ = selcx.infcx().commit_if_ok(|_| {
         let impl_source = match selcx.select(&trait_obligation) {
             Ok(Some(impl_source)) => impl_source,
@@ -1705,12 +1709,12 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
                     ty::Param(_) | ty::Projection(..) | ty::Opaque(..)
                         if selcx.infcx().predicate_must_hold_modulo_regions(
                             &obligation.with(
+                                selcx.tcx(),
                                 ty::Binder::dummy(ty::TraitRef::new(
                                     selcx.tcx().require_lang_item(LangItem::Sized, None),
                                     selcx.tcx().mk_substs_trait(self_ty, &[]),
                                 ))
-                                .without_const()
-                                .to_predicate(selcx.tcx()),
+                                .without_const(),
                             ),
                         ) =>
                     {
@@ -1966,13 +1970,8 @@ fn confirm_pointee_candidate<'cx, 'tcx>(
             tcx.require_lang_item(LangItem::Sized, None),
             tcx.mk_substs_trait(self_ty, &[]),
         ))
-        .without_const()
-        .to_predicate(tcx);
-        obligations.push(Obligation::new(
-            obligation.cause.clone(),
-            obligation.param_env,
-            sized_predicate,
-        ));
+        .without_const();
+        obligations.push(obligation.with(tcx, sized_predicate));
     }
 
     let substs = tcx.mk_substs([self_ty.into()].iter());
@@ -2289,6 +2288,7 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>(
     obligations.extend(std::iter::zip(predicates.predicates, predicates.spans).map(
         |(pred, span)| {
             Obligation::with_depth(
+                tcx,
                 ObligationCause::new(
                     obligation.cause.span,
                     obligation.cause.body_id,
@@ -2342,6 +2342,7 @@ fn assoc_ty_own_obligations<'cx, 'tcx>(
             nested,
         );
         nested.push(Obligation::with_depth(
+            tcx,
             obligation.cause.clone(),
             obligation.recursion_depth + 1,
             obligation.param_env,
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index a7932b332c94b..f5c98558a2525 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -208,6 +208,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                         let recursion_limit = self.tcx().recursion_limit();
                         if !recursion_limit.value_within_limit(self.anon_depth) {
                             let obligation = Obligation::with_depth(
+                                self.tcx(),
                                 self.cause.clone(),
                                 recursion_limit.0,
                                 self.param_env,
diff --git a/compiler/rustc_trait_selection/src/traits/relationships.rs b/compiler/rustc_trait_selection/src/traits/relationships.rs
index 8cf500a466bf2..dfe19a5a86d3b 100644
--- a/compiler/rustc_trait_selection/src/traits/relationships.rs
+++ b/compiler/rustc_trait_selection/src/traits/relationships.rs
@@ -1,8 +1,8 @@
 use crate::infer::InferCtxt;
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
-use crate::traits::{ObligationCause, PredicateObligation};
+use crate::traits::PredicateObligation;
 use rustc_infer::traits::TraitEngine;
-use rustc_middle::ty::{self, ToPredicate};
+use rustc_middle::ty;
 
 pub(crate) fn update<'tcx, T>(
     engine: &mut T,
@@ -25,9 +25,7 @@ pub(crate) fn update<'tcx, T>(
 
         // Then construct a new obligation with Self = () added
         // to the ParamEnv, and see if it holds.
-        let o = rustc_infer::traits::Obligation::new(
-            ObligationCause::dummy(),
-            obligation.param_env,
+        let o = obligation.with(infcx.tcx,
             obligation
                 .predicate
                 .kind()
@@ -38,8 +36,7 @@ pub(crate) fn update<'tcx, T>(
                         constness: tpred.constness,
                         polarity: tpred.polarity,
                     })
-                )
-                .to_predicate(infcx.tcx),
+                ),
         );
         // Don't report overflow errors. Otherwise equivalent to may_hold.
         if let Ok(result) = infcx.probe(|_| infcx.evaluate_obligation(&o)) && result.may_apply() {
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 3671a0d87df57..3995ea58db16c 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -13,7 +13,7 @@ use rustc_infer::traits::ObligationCause;
 use rustc_infer::traits::{Obligation, SelectionError, TraitObligation};
 use rustc_lint_defs::builtin::DEREF_INTO_DYN_SUPERTRAIT;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, ToPredicate, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitable};
 use rustc_target::spec::abi::Abi;
 
 use crate::traits;
@@ -718,9 +718,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         };
 
         let obligation = traits::Obligation::new(
+            tcx,
             cause.clone(),
             param_env,
-            ty::Binder::dummy(trait_ref).without_const().to_predicate(tcx),
+            ty::Binder::dummy(trait_ref).without_const(),
         );
         if !self.infcx.predicate_may_hold(&obligation) {
             return None;
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 28b4bae7cbecf..9d43f72b85f15 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -194,6 +194,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     &mut obligations,
                 );
                 obligations.push(Obligation::with_depth(
+                    self.tcx(),
                     obligation.cause.clone(),
                     obligation.recursion_depth + 1,
                     obligation.param_env,
@@ -482,11 +483,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 super_trait,
                 &mut nested,
             );
-            nested.push(Obligation::new(
-                obligation.cause.clone(),
-                obligation.param_env,
-                normalized_super_trait,
-            ));
+            nested.push(obligation.with(tcx, normalized_super_trait));
         }
 
         let assoc_types: Vec<_> = tcx
@@ -581,11 +578,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     subst_bound,
                     &mut nested,
                 );
-                nested.push(Obligation::new(
-                    obligation.cause.clone(),
-                    obligation.param_env,
-                    normalized_bound,
-                ));
+                nested.push(obligation.with(tcx, normalized_bound));
             }
         }
 
@@ -644,9 +637,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             self.tcx().mk_substs_trait(output_ty, &[]),
         ));
         nested.push(Obligation::new(
+            self.infcx.tcx,
             cause,
             obligation.param_env,
-            tr.to_poly_trait_predicate().to_predicate(self.tcx()),
+            tr.to_poly_trait_predicate(),
         ));
 
         Ok(ImplSourceFnPointerData { fn_ty: self_ty, nested })
@@ -727,11 +721,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // FIXME: Chalk
 
         if !self.tcx().sess.opts.unstable_opts.chalk {
-            nested.push(Obligation::new(
-                obligation.cause.clone(),
-                obligation.param_env,
-                ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind))
-                    .to_predicate(self.tcx()),
+            nested.push(obligation.with(
+                self.tcx(),
+                ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, substs, kind)),
             ));
         }
 
@@ -860,10 +852,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
                 let outlives = ty::OutlivesPredicate(r_a, r_b);
                 nested.push(Obligation::with_depth(
+                    tcx,
                     cause,
                     obligation.recursion_depth + 1,
                     obligation.param_env,
-                    obligation.predicate.rebind(outlives).to_predicate(tcx),
+                    obligation.predicate.rebind(outlives),
                 ));
             }
             _ => bug!(),
@@ -957,10 +950,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
                 let outlives = ty::OutlivesPredicate(r_a, r_b);
                 nested.push(Obligation::with_depth(
+                    tcx,
                     cause,
                     obligation.recursion_depth + 1,
                     obligation.param_env,
-                    obligation.predicate.rebind(outlives).to_predicate(tcx),
+                    obligation.predicate.rebind(outlives),
                 ));
             }
 
@@ -979,6 +973,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                 let predicate_to_obligation = |predicate| {
                     Obligation::with_depth(
+                        tcx,
                         cause.clone(),
                         obligation.recursion_depth + 1,
                         obligation.param_env,
@@ -1255,20 +1250,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         obligation.param_env,
                         cause.clone(),
                         obligation.recursion_depth + 1,
-                        self_ty
-                            .rebind(ty::TraitPredicate {
-                                trait_ref: ty::TraitRef {
-                                    def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
-                                    substs: self.tcx().mk_substs_trait(nested_ty, &[]),
-                                },
-                                constness: ty::BoundConstness::ConstIfConst,
-                                polarity: ty::ImplPolarity::Positive,
-                            })
-                            .to_predicate(tcx),
+                        self_ty.rebind(ty::TraitPredicate {
+                            trait_ref: ty::TraitRef {
+                                def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
+                                substs: self.tcx().mk_substs_trait(nested_ty, &[]),
+                            },
+                            constness: ty::BoundConstness::ConstIfConst,
+                            polarity: ty::ImplPolarity::Positive,
+                        }),
                         &mut nested,
                     );
 
                     nested.push(Obligation::with_depth(
+                        tcx,
                         cause.clone(),
                         obligation.recursion_depth + 1,
                         obligation.param_env,
@@ -1280,18 +1274,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // since it's either not `const Drop` (and we raise an error during selection),
                 // or it's an ADT (and we need to check for a custom impl during selection)
                 _ => {
-                    let predicate = self_ty
-                        .rebind(ty::TraitPredicate {
-                            trait_ref: ty::TraitRef {
-                                def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
-                                substs: self.tcx().mk_substs_trait(nested_ty, &[]),
-                            },
-                            constness: ty::BoundConstness::ConstIfConst,
-                            polarity: ty::ImplPolarity::Positive,
-                        })
-                        .to_predicate(tcx);
+                    let predicate = self_ty.rebind(ty::TraitPredicate {
+                        trait_ref: ty::TraitRef {
+                            def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
+                            substs: self.tcx().mk_substs_trait(nested_ty, &[]),
+                        },
+                        constness: ty::BoundConstness::ConstIfConst,
+                        polarity: ty::ImplPolarity::Positive,
+                    });
 
                     nested.push(Obligation::with_depth(
+                        tcx,
                         cause.clone(),
                         obligation.recursion_depth + 1,
                         obligation.param_env,
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 3a899c03b4c94..c369c5de52bb1 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -445,7 +445,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 ty::PredicateKind::Trait(t) => {
                     let t = bound_predicate.rebind(t);
                     debug_assert!(!t.has_escaping_bound_vars());
-                    let obligation = obligation.with(t);
+                    let obligation = obligation.with(self.tcx(), t);
                     self.evaluate_trait_predicate_recursively(previous_stack, obligation)
                 }
 
@@ -596,7 +596,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                 ty::PredicateKind::Projection(data) => {
                     let data = bound_predicate.rebind(data);
-                    let project_obligation = obligation.with(data);
+                    let project_obligation = obligation.with(self.tcx(), data);
                     match project::poly_project_and_unify_type(self, &project_obligation) {
                         ProjectAndUnifyResult::Holds(mut subobligations) => {
                             'compute_res: {
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index fc0a9f6900336..d05e893de433a 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -4,7 +4,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
 use rustc_span::Span;
 
 use std::iter;
@@ -324,7 +324,7 @@ impl<'tcx> WfPredicates<'tcx> {
             extend_cause_with_original_assoc_item_obligation(
                 tcx, trait_ref, item, &mut cause, predicate,
             );
-            traits::Obligation::with_depth(cause, depth, param_env, predicate)
+            traits::Obligation::with_depth(tcx, cause, depth, param_env, predicate)
         };
 
         if let Elaborate::All = elaborate {
@@ -356,10 +356,11 @@ impl<'tcx> WfPredicates<'tcx> {
                         }
                     }
                     traits::Obligation::with_depth(
+                        tcx,
                         cause,
                         depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(tcx),
+                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
                     )
                 }),
         );
@@ -407,10 +408,11 @@ impl<'tcx> WfPredicates<'tcx> {
                 .filter(|arg| !arg.has_escaping_bound_vars())
                 .map(|arg| {
                     traits::Obligation::with_depth(
+                        tcx,
                         cause.clone(),
                         depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)).to_predicate(tcx),
+                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
                     )
                 }),
         );
@@ -424,10 +426,11 @@ impl<'tcx> WfPredicates<'tcx> {
                 substs: self.tcx.mk_substs_trait(subty, &[]),
             };
             self.out.push(traits::Obligation::with_depth(
+                self.tcx,
                 cause,
                 self.recursion_depth,
                 self.param_env,
-                ty::Binder::dummy(trait_ref).without_const().to_predicate(self.tcx),
+                ty::Binder::dummy(trait_ref).without_const(),
             ));
         }
     }
@@ -454,10 +457,10 @@ impl<'tcx> WfPredicates<'tcx> {
                             self.out.extend(obligations);
 
                             let predicate =
-                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct))
-                                    .to_predicate(self.tcx());
+                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
                             let cause = self.cause(traits::WellFormed(None));
                             self.out.push(traits::Obligation::with_depth(
+                                self.tcx(),
                                 cause,
                                 self.recursion_depth,
                                 self.param_env,
@@ -468,11 +471,11 @@ impl<'tcx> WfPredicates<'tcx> {
                             let cause = self.cause(traits::WellFormed(None));
 
                             self.out.push(traits::Obligation::with_depth(
+                                self.tcx(),
                                 cause,
                                 self.recursion_depth,
                                 self.param_env,
-                                ty::Binder::dummy(ty::PredicateKind::WellFormed(ct.into()))
-                                    .to_predicate(self.tcx()),
+                                ty::Binder::dummy(ty::PredicateKind::WellFormed(ct.into())),
                             ));
                         }
                         ty::ConstKind::Error(_)
@@ -556,13 +559,13 @@ impl<'tcx> WfPredicates<'tcx> {
                     if !r.has_escaping_bound_vars() && !rty.has_escaping_bound_vars() {
                         let cause = self.cause(traits::ReferenceOutlivesReferent(ty));
                         self.out.push(traits::Obligation::with_depth(
+                            self.tcx(),
                             cause,
                             depth,
                             param_env,
                             ty::Binder::dummy(ty::PredicateKind::TypeOutlives(
                                 ty::OutlivesPredicate(rty, r),
-                            ))
-                            .to_predicate(self.tcx()),
+                            )),
                         ));
                     }
                 }
@@ -656,11 +659,11 @@ impl<'tcx> WfPredicates<'tcx> {
                         let tcx = self.tcx();
                         self.out.extend(component_traits.map(|did| {
                             traits::Obligation::with_depth(
+                                tcx,
                                 cause.clone(),
                                 depth,
                                 param_env,
-                                ty::Binder::dummy(ty::PredicateKind::ObjectSafe(did))
-                                    .to_predicate(tcx),
+                                ty::Binder::dummy(ty::PredicateKind::ObjectSafe(did)),
                             )
                         }));
                     }
@@ -681,11 +684,11 @@ impl<'tcx> WfPredicates<'tcx> {
                 ty::Infer(_) => {
                     let cause = self.cause(traits::WellFormed(None));
                     self.out.push(traits::Obligation::with_depth(
+                        self.tcx(),
                         cause,
                         self.recursion_depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into()))
-                            .to_predicate(self.tcx()),
+                        ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())),
                     ));
                 }
             }
@@ -724,7 +727,13 @@ impl<'tcx> WfPredicates<'tcx> {
                 if remap_constness {
                     pred = pred.without_const(self.tcx);
                 }
-                traits::Obligation::with_depth(cause, self.recursion_depth, self.param_env, pred)
+                traits::Obligation::with_depth(
+                    self.tcx,
+                    cause,
+                    self.recursion_depth,
+                    self.param_env,
+                    pred,
+                )
             })
             .filter(|pred| !pred.has_escaping_bound_vars())
             .collect()
@@ -794,10 +803,11 @@ impl<'tcx> WfPredicates<'tcx> {
                 let outlives =
                     ty::Binder::dummy(ty::OutlivesPredicate(explicit_bound, implicit_bound));
                 self.out.push(traits::Obligation::with_depth(
+                    self.tcx,
                     cause,
                     self.recursion_depth,
                     self.param_env,
-                    outlives.to_predicate(self.tcx),
+                    outlives,
                 ));
             }
         }
diff --git a/compiler/rustc_traits/src/evaluate_obligation.rs b/compiler/rustc_traits/src/evaluate_obligation.rs
index 493d5de0807a2..e94c8efe69a92 100644
--- a/compiler/rustc_traits/src/evaluate_obligation.rs
+++ b/compiler/rustc_traits/src/evaluate_obligation.rs
@@ -26,7 +26,7 @@ fn evaluate_obligation<'tcx>(
     let ParamEnvAnd { param_env, value: predicate } = goal;
 
     let mut selcx = SelectionContext::with_query_mode(&infcx, TraitQueryMode::Canonical);
-    let obligation = Obligation::new(ObligationCause::dummy(), param_env, predicate);
+    let obligation = Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate);
 
     selcx.evaluate_root_obligation(&obligation)
 }
diff --git a/compiler/rustc_traits/src/type_op.rs b/compiler/rustc_traits/src/type_op.rs
index 98cb3f21555ac..9eceae8b44f8e 100644
--- a/compiler/rustc_traits/src/type_op.rs
+++ b/compiler/rustc_traits/src/type_op.rs
@@ -91,7 +91,12 @@ impl<'me, 'tcx> AscribeUserTypeCx<'me, 'tcx> {
     }
 
     fn prove_predicate(&self, predicate: Predicate<'tcx>, cause: ObligationCause<'tcx>) {
-        self.ocx.register_obligation(Obligation::new(cause, self.param_env, predicate));
+        self.ocx.register_obligation(Obligation::new(
+            self.ocx.infcx.tcx,
+            cause,
+            self.param_env,
+            predicate,
+        ));
     }
 
     fn tcx(&self) -> TyCtxt<'tcx> {
@@ -256,5 +261,5 @@ pub fn type_op_prove_predicate_with_cause<'tcx>(
     cause: ObligationCause<'tcx>,
 ) {
     let (param_env, ProvePredicate { predicate }) = key.into_parts();
-    ocx.register_obligation(Obligation::new(cause, param_env, predicate));
+    ocx.register_obligation(Obligation::new(ocx.infcx.tcx, cause, param_env, predicate));
 }
diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index 34247c0584508..c20ca69a1c6f1 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -338,6 +338,7 @@ pub macro debug_assert_matches($($arg:tt)*) {
 /// ```
 #[macro_export]
 #[stable(feature = "matches_macro", since = "1.42.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "matches_macro")]
 macro_rules! matches {
     ($expression:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )? $(,)?) => {
         match $expression {
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs
index d80637055829d..cb0b8d4a9bc19 100644
--- a/src/librustdoc/clean/blanket_impl.rs
+++ b/src/librustdoc/clean/blanket_impl.rs
@@ -76,6 +76,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                 for predicate in predicates {
                     debug!("testing predicate {:?}", predicate);
                     let obligation = traits::Obligation::new(
+                        infcx.tcx,
                         traits::ObligationCause::dummy(),
                         param_env,
                         predicate,
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 9b1cac85cfd58..5ec2fe47e0156 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -217,10 +217,7 @@ h1 a,
 .search-results a,
 .module-item .stab,
 .import-item .stab,
-.result-name .primitive > i, .result-name .keyword > i,
-.method .where,
-.fn .where,
-.where.fmt-newline {
+.result-name .primitive > i, .result-name .keyword > i {
 	color: var(--main-color);
 }
 
@@ -1162,6 +1159,8 @@ pre.rust .doccomment {
 	width: max-content;
 	top: -2px;
 	z-index: 1;
+	background-color: var(--tooltip-background-color);
+	color: var(--tooltip-color);
 }
 
 .example-wrap .tooltip::before {
@@ -1170,10 +1169,10 @@ pre.rust .doccomment {
 	top: 50%;
 	left: 16px;
 	margin-top: -5px;
-	border-width: 5px;
-	border-style: solid;
 	display: none;
 	z-index: 1;
+	border: 5px solid transparent;
+	border-right-color: var(--tooltip-background-color);
 }
 
 .example-wrap.ignore .tooltip::after {
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index db311bccd6dc4..0e4dacb28f7cd 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -65,6 +65,8 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--test-arrow-hover-background-color: rgba(57, 175, 215, 0.368);
 	--target-background-color: rgba(255, 236, 164, 0.06);
 	--target-border-color: rgba(255, 180, 76, 0.85);
+	--tooltip-background-color: #314559;
+	--tooltip-color: #c5c5c5;
 	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
 		drop-shadow(0 1px 0 #fff)
 		drop-shadow(-1px 0 0 #fff)
@@ -160,15 +162,6 @@ details.rustdoc-toggle > summary::before {
 	color: #788797;
 }
 
-.tooltip::after {
-	background-color: #314559;
-	color: #c5c5c5;
-}
-
-.tooltip::before {
-	border-color: transparent #314559 transparent transparent;
-}
-
 #titles > button.selected {
 	background-color: #141920 !important;
 	border-bottom: 1px solid #ffb44c !important;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index b2f2c77f5475a..8e00591179f1f 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -60,6 +60,8 @@
 	--test-arrow-hover-background-color: #4e8bca;
 	--target-background-color: #494a3d;
 	--target-border-color: #bb7410;
+	--tooltip-background-color: #000;
+	--tooltip-color: #fff;
 	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
 		drop-shadow(0 1px 0 #fff)
 		drop-shadow(-1px 0 0 #fff)
@@ -82,16 +84,6 @@ details.rustdoc-toggle > summary::before {
 	filter: invert(100%);
 }
 
-.tooltip::after {
-	background-color: #000;
-	color: #fff;
-	border-color: #000;
-}
-
-.tooltip::before {
-	border-color: transparent black transparent transparent;
-}
-
 #titles > button:not(.selected) {
 	background-color: #252525;
 	border-top-color: #252525;
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index e81327956888b..e23e3682b166e 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -58,8 +58,10 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #f5f5f5;
 	--test-arrow-hover-background-color: #4e8bca;
-	--target-background-color: #fdFfd3;
+	--target-background-color: #fdffd3;
 	--target-border-color: #ad7c37;
+	--tooltip-background-color: #fdffd3;
+	--tooltip-color: #fff;
 	--rust-logo-filter: initial;
 	/* match border-color; uses https://codepen.io/sosuke/pen/Pjoqqp */
 	--crate-search-div-filter: invert(100%) sepia(0%) saturate(4223%) hue-rotate(289deg)
@@ -75,15 +77,6 @@ body.source .example-wrap pre.rust a {
 	background: #eee;
 }
 
-.tooltip::after {
-	background-color: #000;
-	color: #fff;
-}
-
-.tooltip::before {
-	border-color: transparent black transparent transparent;
-}
-
 #titles > button:not(.selected) {
 	background-color: #e6e6e6;
 	border-top-color: #e6e6e6;
diff --git a/src/librustdoc/html/static/js/settings.js b/src/librustdoc/html/static/js/settings.js
index 95cc265f1bdf6..5256ae916a771 100644
--- a/src/librustdoc/html/static/js/settings.js
+++ b/src/librustdoc/html/static/js/settings.js
@@ -9,13 +9,16 @@
     const isSettingsPage = window.location.pathname.endsWith("/settings.html");
 
     function changeSetting(settingName, value) {
+        if (settingName === "theme") {
+            const useSystem = value === "system preference" ? "true" : "false";
+            updateLocalStorage("use-system-theme", useSystem);
+        }
         updateLocalStorage(settingName, value);
 
         switch (settingName) {
             case "theme":
             case "preferred-dark-theme":
             case "preferred-light-theme":
-            case "use-system-theme":
                 updateSystemTheme();
                 updateLightAndDark();
                 break;
@@ -45,7 +48,6 @@
     }
 
     function showLightAndDark() {
-        addClass(document.getElementById("theme").parentElement, "hidden");
         removeClass(document.getElementById("preferred-light-theme").parentElement, "hidden");
         removeClass(document.getElementById("preferred-dark-theme").parentElement, "hidden");
     }
@@ -53,11 +55,11 @@
     function hideLightAndDark() {
         addClass(document.getElementById("preferred-light-theme").parentElement, "hidden");
         addClass(document.getElementById("preferred-dark-theme").parentElement, "hidden");
-        removeClass(document.getElementById("theme").parentElement, "hidden");
     }
 
     function updateLightAndDark() {
-        if (getSettingValue("use-system-theme") !== "false") {
+        const useSystem = getSettingValue("use-system-theme");
+        if (useSystem === "true" || (useSystem === null && getSettingValue("theme") === null)) {
             showLightAndDark();
         } else {
             hideLightAndDark();
@@ -91,7 +93,18 @@
         });
         onEachLazy(settingsElement.querySelectorAll("input[type=\"radio\"]"), elem => {
             const settingId = elem.name;
-            const settingValue = getSettingValue(settingId);
+            let settingValue = getSettingValue(settingId);
+            if (settingId === "theme") {
+                const useSystem = getSettingValue("use-system-theme");
+                if (useSystem === "true" || settingValue === null) {
+                    if (useSystem !== "false") {
+                        settingValue = "system preference";
+                    } else {
+                        // This is the default theme.
+                        settingValue = "light";
+                    }
+                }
+            }
             if (settingValue !== null && settingValue !== "null") {
                 elem.checked = settingValue === elem.value;
             }
@@ -120,26 +133,30 @@
 
             if (setting["options"] !== undefined) {
                 // This is a select setting.
-                output += `<div class="radio-line" id="${js_data_name}">\
-                        <span class="setting-name">${setting_name}</span>\
-                        <div class="choices">`;
+                output += `\
+<div class="radio-line" id="${js_data_name}">
+    <span class="setting-name">${setting_name}</span>
+<div class="choices">`;
                 onEach(setting["options"], option => {
                     const checked = option === setting["default"] ? " checked" : "";
+                    const full = `${js_data_name}-${option.replace(/ /g,"-")}`;
 
-                    output += `<label for="${js_data_name}-${option}" class="choice">\
-                           <input type="radio" name="${js_data_name}" \
-                                id="${js_data_name}-${option}" value="${option}"${checked}>\
-                           <span>${option}</span>\
-                         </label>`;
+                    output += `\
+<label for="${full}" class="choice">
+    <input type="radio" name="${js_data_name}"
+        id="${full}" value="${option}"${checked}>
+    <span>${option}</span>
+</label>`;
                 });
                 output += "</div></div>";
             } else {
                 // This is a toggle.
                 const checked = setting["default"] === true ? " checked" : "";
-                output += `<label class="toggle">\
-                        <input type="checkbox" id="${js_data_name}"${checked}>\
-                        <span class="label">${setting_name}</span>\
-                    </label>`;
+                output += `\
+<label class="toggle">\
+    <input type="checkbox" id="${js_data_name}"${checked}>\
+    <span class="label">${setting_name}</span>\
+</label>`;
             }
             output += "</div>";
         }
@@ -156,16 +173,11 @@
         theme_names.push("light", "dark", "ayu");
 
         const settings = [
-            {
-                "name": "Use system theme",
-                "js_name": "use-system-theme",
-                "default": true,
-            },
             {
                 "name": "Theme",
                 "js_name": "theme",
-                "default": "light",
-                "options": theme_names,
+                "default": "system preference",
+                "options": theme_names.concat("system preference"),
             },
             {
                 "name": "Preferred light theme",
diff --git a/src/test/rustdoc-gui/codeblock-tooltip.goml b/src/test/rustdoc-gui/codeblock-tooltip.goml
index 8e681a2a0c3a3..caa1ab8f31eb4 100644
--- a/src/test/rustdoc-gui/codeblock-tooltip.goml
+++ b/src/test/rustdoc-gui/codeblock-tooltip.goml
@@ -4,7 +4,7 @@ show-text: true
 
 define-function: (
     "check-colors",
-    (theme),
+    (theme, background, color, border),
     [
         // Setting the theme.
         ("local-storage", {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}),
@@ -30,6 +30,25 @@ define-function: (
             ".docblock .example-wrap.compile_fail",
             {"border-left": "2px solid rgb(255, 0, 0)"},
         )),
+        ("assert-css", (
+            ".docblock .example-wrap.compile_fail .tooltip::after",
+            {
+                "content": '"This example deliberately fails to compile"',
+                "text-align": "center",
+                "padding": "5px 3px 3px",
+                "background-color": |background|,
+                "color": |color|,
+                "border": "1px solid " + |border|,
+            },
+        )),
+        ("assert-css", (
+            ".docblock .example-wrap.compile_fail .tooltip::before",
+            {
+                "border-width": "5px",
+                "border-style": "solid",
+                "border-color": "rgba(0, 0, 0, 0) " + |background| + " rgba(0, 0, 0, 0) rgba(0, 0, 0, 0)",
+            },
+        )),
 
         // should_panic block
         ("assert-css", (
@@ -51,6 +70,25 @@ define-function: (
             ".docblock .example-wrap.should_panic",
             {"border-left": "2px solid rgb(255, 0, 0)"},
         )),
+        ("assert-css", (
+            ".docblock .example-wrap.should_panic .tooltip::after",
+            {
+                "content": '"This example panics"',
+                "text-align": "center",
+                "padding": "5px 3px 3px",
+                "background-color": |background|,
+                "color": |color|,
+                "border": "1px solid " + |border|,
+            },
+        )),
+        ("assert-css", (
+            ".docblock .example-wrap.should_panic .tooltip::before",
+            {
+                "border-width": "5px",
+                "border-style": "solid",
+                "border-color": "rgba(0, 0, 0, 0) " + |background| + " rgba(0, 0, 0, 0) rgba(0, 0, 0, 0)",
+            },
+        )),
 
         // ignore block
         ("assert-css", (
@@ -72,9 +110,43 @@ define-function: (
             ".docblock .example-wrap.ignore",
             {"border-left": "2px solid rgb(255, 142, 0)"},
         )),
+        ("assert-css", (
+            ".docblock .example-wrap.ignore .tooltip::after",
+            {
+                "content": '"This example is not tested"',
+                "text-align": "center",
+                "padding": "5px 3px 3px",
+                "background-color": |background|,
+                "color": |color|,
+                "border": "1px solid " + |border|,
+            },
+        )),
+        ("assert-css", (
+            ".docblock .example-wrap.ignore .tooltip::before",
+            {
+                "border-width": "5px",
+                "border-style": "solid",
+                "border-color": "rgba(0, 0, 0, 0) " + |background| + " rgba(0, 0, 0, 0) rgba(0, 0, 0, 0)",
+            },
+        )),
     ],
 )
 
-call-function: ("check-colors", ("ayu"))
-call-function: ("check-colors", ("dark"))
-call-function: ("check-colors", ("light"))
+call-function: ("check-colors", {
+    "theme": "ayu",
+    "background": "rgb(49, 69, 89)",
+    "color": "rgb(197, 197, 197)",
+    "border": "rgb(92, 103, 115)",
+})
+call-function: ("check-colors", {
+    "theme": "dark",
+    "background": "rgb(0, 0, 0)",
+    "color": "rgb(255, 255, 255)",
+    "border": "rgb(224, 224, 224)",
+})
+call-function: ("check-colors", {
+    "theme": "light",
+    "background": "rgb(253, 255, 211)",
+    "color": "rgb(255, 255, 255)",
+    "border": "rgb(224, 224, 224)",
+})
diff --git a/src/test/rustdoc-gui/settings.goml b/src/test/rustdoc-gui/settings.goml
index 7e7971d47fbca..fc3beaa53fafc 100644
--- a/src/test/rustdoc-gui/settings.goml
+++ b/src/test/rustdoc-gui/settings.goml
@@ -37,8 +37,7 @@ click: "#settings-menu"
 wait-for: "#settings"
 
 // We check that the "Use system theme" is disabled.
-assert-property: ("#use-system-theme", {"checked": "false"})
-assert: "//*[@class='setting-line']//span[text()='Use system theme']"
+assert-property: ("#theme-system-preference", {"checked": "false"})
 // Meaning that only the "theme" menu is showing up.
 assert: ".setting-line:not(.hidden) #theme"
 assert: ".setting-line.hidden #preferred-dark-theme"
@@ -115,13 +114,6 @@ assert-css: (
         "border-color": "rgb(221, 221, 221)",
     },
 )
-assert-css: (
-    "#use-system-theme",
-    {
-        "background-color": "rgba(0, 0, 0, 0)",
-        "border-color": "rgb(221, 221, 221)",
-    }
-)
 // Let's start with the hover for toggles.
 move-cursor-to: "#auto-hide-large-items"
 assert-css: (
@@ -131,14 +123,6 @@ assert-css: (
         "border-color": "rgb(33, 150, 243)",
     },
 )
-move-cursor-to: "#use-system-theme"
-assert-css: (
-    "#use-system-theme",
-    {
-        "background-color": "rgba(0, 0, 0, 0)",
-        "border-color": "rgb(33, 150, 243)",
-    }
-)
 move-cursor-to: "#settings-menu > a"
 // Let's now check with the focus for toggles.
 focus: "#auto-hide-large-items"
@@ -150,15 +134,6 @@ assert-css: (
         "box-shadow": "rgb(33, 150, 243) 0px 0px 1px 1px",
     },
 )
-focus: "#use-system-theme"
-assert-css: (
-    "#use-system-theme",
-    {
-        "background-color": "rgba(0, 0, 0, 0)",
-        "border-color": "rgb(221, 221, 221)",
-        "box-shadow": "rgb(33, 150, 243) 0px 0px 1px 1px",
-    },
-)
 // Now we check we both focus and hover for toggles.
 move-cursor-to: "#auto-hide-large-items"
 focus: "#auto-hide-large-items"
@@ -170,24 +145,12 @@ assert-css: (
         "box-shadow": "rgb(33, 150, 243) 0px 0px 1px 1px",
     },
 )
-move-cursor-to: "#use-system-theme"
-focus: "#use-system-theme"
-assert-css: (
-    "#use-system-theme",
-    {
-        "background-color": "rgba(0, 0, 0, 0)",
-        "border-color": "rgb(33, 150, 243)",
-        "box-shadow": "rgb(33, 150, 243) 0px 0px 1px 1px",
-    },
-)
 
 // We now switch the display.
-click: "#use-system-theme"
+click: "#theme-system-preference"
 // Wait for the hidden element to show up.
 wait-for: ".setting-line:not(.hidden) #preferred-dark-theme"
 assert: ".setting-line:not(.hidden) #preferred-light-theme"
-// Check that the theme picking is hidden.
-assert: ".setting-line.hidden #theme"
 
 // We check their text as well.
 assert-text: ("#preferred-dark-theme .setting-name", "Preferred dark theme")
diff --git a/src/test/rustdoc-gui/theme-change.goml b/src/test/rustdoc-gui/theme-change.goml
index b1de3c366149a..cc47f1f450c5a 100644
--- a/src/test/rustdoc-gui/theme-change.goml
+++ b/src/test/rustdoc-gui/theme-change.goml
@@ -2,31 +2,66 @@
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
 local-storage: {"rustdoc-use-system-theme": "false", "rustdoc-theme": "dark"}
 reload:
+
+store-value: (background_light, "rgb(255, 255, 255)")
+store-value: (background_dark, "rgb(53, 53, 53)")
+store-value: (background_ayu, "rgb(15, 20, 25)")
+
 click: "#settings-menu"
 wait-for: "#theme-ayu"
 click: "#theme-ayu"
 // should be the ayu theme so let's check the color.
-wait-for-css: ("body", { "background-color": "rgb(15, 20, 25)" })
+wait-for-css: ("body", { "background-color": |background_ayu| })
 assert-local-storage: { "rustdoc-theme": "ayu" }
 click: "#theme-light"
 // should be the light theme so let's check the color.
-wait-for-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+wait-for-css: ("body", { "background-color": |background_light| })
 assert-local-storage: { "rustdoc-theme": "light" }
 click: "#theme-dark"
 // Should be the dark theme so let's check the color.
-wait-for-css: ("body", { "background-color": "rgb(53, 53, 53)" })
+wait-for-css: ("body", { "background-color": |background_dark| })
 assert-local-storage: { "rustdoc-theme": "dark" }
 
+local-storage: {
+    "rustdoc-preferred-light-theme": "light",
+    "rustdoc-preferred-dark-theme": "light",
+}
 goto: "file://" + |DOC_PATH| + "/settings.html"
+
 wait-for: "#settings"
 click: "#theme-light"
-wait-for-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+wait-for-css: ("body", { "background-color": |background_light| })
 assert-local-storage: { "rustdoc-theme": "light" }
 
 click: "#theme-dark"
-wait-for-css: ("body", { "background-color": "rgb(53, 53, 53)" })
+wait-for-css: ("body", { "background-color": |background_dark| })
 assert-local-storage: { "rustdoc-theme": "dark" }
 
 click: "#theme-ayu"
-wait-for-css: ("body", { "background-color": "rgb(15, 20, 25)" })
+wait-for-css: ("body", { "background-color": |background_ayu| })
 assert-local-storage: { "rustdoc-theme": "ayu" }
+
+assert-local-storage-false: { "rustdoc-use-system-theme": "true" }
+click: "#theme-system-preference"
+wait-for: ".setting-line:not(.hidden) #preferred-light-theme"
+assert-local-storage: { "rustdoc-use-system-theme": "true" }
+// We click on both preferred light and dark themes to be sure that there is a change.
+click: "#preferred-light-theme-dark"
+click: "#preferred-dark-theme-dark"
+wait-for-css: ("body", { "background-color": |background_dark| })
+
+reload:
+// Ensure that the "preferred themes" are still displayed.
+wait-for: ".setting-line:not(.hidden) #preferred-light-theme"
+click: "#theme-light"
+wait-for-css: ("body", { "background-color": |background_light| })
+assert-local-storage: { "rustdoc-theme": "light" }
+// Ensure it's now hidden again
+wait-for: ".setting-line.hidden #preferred-light-theme"
+// And ensure the theme was rightly set.
+wait-for-css: ("body", { "background-color": |background_light| })
+assert-local-storage: { "rustdoc-theme": "light" }
+
+reload:
+wait-for: "#settings"
+assert: ".setting-line.hidden #preferred-light-theme"
diff --git a/src/test/ui/async-await/in-trait/early-bound-1.rs b/src/test/ui/async-await/in-trait/early-bound-1.rs
new file mode 100644
index 0000000000000..6b3b142014bd3
--- /dev/null
+++ b/src/test/ui/async-await/in-trait/early-bound-1.rs
@@ -0,0 +1,17 @@
+// check-pass
+// edition:2021
+
+#![feature(async_fn_in_trait)]
+#![allow(incomplete_features)]
+
+pub trait Foo {
+    async fn foo(&mut self);
+}
+
+struct MyFoo<'a>(&'a mut ());
+
+impl<'a> Foo for MyFoo<'a> {
+    async fn foo(&mut self) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/in-trait/early-bound-2.rs b/src/test/ui/async-await/in-trait/early-bound-2.rs
new file mode 100644
index 0000000000000..270443229b054
--- /dev/null
+++ b/src/test/ui/async-await/in-trait/early-bound-2.rs
@@ -0,0 +1,15 @@
+// check-pass
+// edition:2021
+
+#![feature(async_fn_in_trait)]
+#![allow(incomplete_features)]
+
+pub trait Foo {
+    async fn foo(&mut self);
+}
+
+impl<T: Foo> Foo for &mut T {
+    async fn foo(&mut self) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/consts/const-eval/issue-104390.rs b/src/test/ui/consts/const-eval/issue-104390.rs
new file mode 100644
index 0000000000000..602d818245a0d
--- /dev/null
+++ b/src/test/ui/consts/const-eval/issue-104390.rs
@@ -0,0 +1,10 @@
+fn f1() -> impl Sized { & 2E } //~ ERROR expected at least one digit in exponent
+fn f2() -> impl Sized { && 2E } //~ ERROR expected at least one digit in exponent
+fn f3() -> impl Sized { &'a 2E } //~ ERROR expected at least one digit in exponent
+//~^ ERROR borrow expressions cannot be annotated with lifetimes
+fn f4() -> impl Sized { &'static 2E } //~ ERROR expected at least one digit in exponent
+//~^ ERROR borrow expressions cannot be annotated with lifetimes
+fn f5() -> impl Sized { *& 2E } //~ ERROR expected at least one digit in exponent
+fn f6() -> impl Sized { &'_ 2E } //~ ERROR expected at least one digit in exponent
+//~^ ERROR borrow expressions cannot be annotated with lifetimes
+fn main() {}
diff --git a/src/test/ui/consts/const-eval/issue-104390.stderr b/src/test/ui/consts/const-eval/issue-104390.stderr
new file mode 100644
index 0000000000000..865b9996ea395
--- /dev/null
+++ b/src/test/ui/consts/const-eval/issue-104390.stderr
@@ -0,0 +1,65 @@
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:1:27
+   |
+LL | fn f1() -> impl Sized { & 2E }
+   |                           ^^
+
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:2:28
+   |
+LL | fn f2() -> impl Sized { && 2E }
+   |                            ^^
+
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:3:29
+   |
+LL | fn f3() -> impl Sized { &'a 2E }
+   |                             ^^
+
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:5:34
+   |
+LL | fn f4() -> impl Sized { &'static 2E }
+   |                                  ^^
+
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:7:28
+   |
+LL | fn f5() -> impl Sized { *& 2E }
+   |                            ^^
+
+error: expected at least one digit in exponent
+  --> $DIR/issue-104390.rs:8:29
+   |
+LL | fn f6() -> impl Sized { &'_ 2E }
+   |                             ^^
+
+error: borrow expressions cannot be annotated with lifetimes
+  --> $DIR/issue-104390.rs:3:25
+   |
+LL | fn f3() -> impl Sized { &'a 2E }
+   |                         ^--^^^
+   |                          |
+   |                          annotated with lifetime here
+   |                          help: remove the lifetime annotation
+
+error: borrow expressions cannot be annotated with lifetimes
+  --> $DIR/issue-104390.rs:5:25
+   |
+LL | fn f4() -> impl Sized { &'static 2E }
+   |                         ^-------^^^
+   |                          |
+   |                          annotated with lifetime here
+   |                          help: remove the lifetime annotation
+
+error: borrow expressions cannot be annotated with lifetimes
+  --> $DIR/issue-104390.rs:8:25
+   |
+LL | fn f6() -> impl Sized { &'_ 2E }
+   |                         ^--^^^
+   |                          |
+   |                          annotated with lifetime here
+   |                          help: remove the lifetime annotation
+
+error: aborting due to 9 previous errors
+
diff --git a/src/test/ui/dyn-star/return.rs b/src/test/ui/dyn-star/return.rs
new file mode 100644
index 0000000000000..fa3d8d7d5064c
--- /dev/null
+++ b/src/test/ui/dyn-star/return.rs
@@ -0,0 +1,10 @@
+// check-pass
+
+#![feature(dyn_star)]
+//~^ WARN the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+
+fn _foo() -> dyn* Unpin {
+    4usize
+}
+
+fn main() {}
diff --git a/src/test/ui/dyn-star/return.stderr b/src/test/ui/dyn-star/return.stderr
new file mode 100644
index 0000000000000..e000351a68f54
--- /dev/null
+++ b/src/test/ui/dyn-star/return.stderr
@@ -0,0 +1,11 @@
+warning: the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/return.rs:3:12
+   |
+LL | #![feature(dyn_star)]
+   |            ^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/lint/issue-104392.rs b/src/test/ui/lint/issue-104392.rs
new file mode 100644
index 0000000000000..d5608edb46f04
--- /dev/null
+++ b/src/test/ui/lint/issue-104392.rs
@@ -0,0 +1,11 @@
+fn main() {
+    { unsafe 92 } //~ ERROR expected `{`, found `92`
+}
+
+fn foo() {
+    { mod 92 } //~ ERROR expected identifier, found `92`
+}
+
+fn bar() {
+    { trait 92 } //~ ERROR expected identifier, found `92`
+}
diff --git a/src/test/ui/lint/issue-104392.stderr b/src/test/ui/lint/issue-104392.stderr
new file mode 100644
index 0000000000000..8e466439ae643
--- /dev/null
+++ b/src/test/ui/lint/issue-104392.stderr
@@ -0,0 +1,27 @@
+error: expected `{`, found `92`
+  --> $DIR/issue-104392.rs:2:14
+   |
+LL |     { unsafe 92 }
+   |       ------ ^^ expected `{`
+   |       |
+   |       while parsing this `unsafe` expression
+   |
+help: try placing this code inside a block
+   |
+LL |     { unsafe { 92 } }
+   |              +    +
+
+error: expected identifier, found `92`
+  --> $DIR/issue-104392.rs:6:11
+   |
+LL |     { mod 92 }
+   |           ^^ expected identifier
+
+error: expected identifier, found `92`
+  --> $DIR/issue-104392.rs:10:13
+   |
+LL |     { trait 92 }
+   |             ^^ expected identifier
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/typeck/issue-103899.rs b/src/test/ui/typeck/issue-103899.rs
index 9d5341dab42f3..ac9e4c716962f 100644
--- a/src/test/ui/typeck/issue-103899.rs
+++ b/src/test/ui/typeck/issue-103899.rs
@@ -1,9 +1,6 @@
 // check-fail
 // failure-status: 101
-// normalize-stderr-test "note: .*" -> ""
-// normalize-stderr-test "thread 'rustc' .*" -> ""
-// normalize-stderr-test " .*\n" -> ""
-// normalize-stderr-test "  .*\n" -> ""
+// dont-check-compiler-stderr
 // known-bug: #103899
 
 trait BaseWithAssoc {
diff --git a/src/test/ui/typeck/issue-103899.stderr b/src/test/ui/typeck/issue-103899.stderr
deleted file mode 100644
index 836c6ee486f51..0000000000000
--- a/src/test/ui/typeck/issue-103899.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-
-stack
-error:
-
-
-
-
-
-
-
-
-query#0#1end
\ No newline at end of file
diff --git a/src/test/ui/typeck/issue-104510-ice.rs b/src/test/ui/typeck/issue-104510-ice.rs
new file mode 100644
index 0000000000000..157bdf07e3826
--- /dev/null
+++ b/src/test/ui/typeck/issue-104510-ice.rs
@@ -0,0 +1,16 @@
+// needs-asm-support
+// only-x86_64
+
+struct W<T: ?Sized>(Oops);
+//~^ ERROR cannot find type `Oops` in this scope
+
+unsafe fn test() {
+    let j = W(());
+    let pointer = &j as *const _;
+    core::arch::asm!(
+        "nop",
+        in("eax") pointer,
+    );
+}
+
+fn main() {}
diff --git a/src/test/ui/typeck/issue-104510-ice.stderr b/src/test/ui/typeck/issue-104510-ice.stderr
new file mode 100644
index 0000000000000..ddb510ef04772
--- /dev/null
+++ b/src/test/ui/typeck/issue-104510-ice.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Oops` in this scope
+  --> $DIR/issue-104510-ice.rs:4:21
+   |
+LL | struct W<T: ?Sized>(Oops);
+   |                     ^^^^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.
diff --git a/src/tools/clippy/clippy_lints/src/dereference.rs b/src/tools/clippy/clippy_lints/src/dereference.rs
index a37ee82d4c8ac..218dbeaddcade 100644
--- a/src/tools/clippy/clippy_lints/src/dereference.rs
+++ b/src/tools/clippy/clippy_lints/src/dereference.rs
@@ -1156,7 +1156,7 @@ fn needless_borrow_impl_arg_position<'tcx>(
             }
 
             let predicate = EarlyBinder(predicate).subst(cx.tcx, &substs_with_referent_ty);
-            let obligation = Obligation::new(ObligationCause::dummy(), cx.param_env, predicate);
+            let obligation = Obligation::new(cx.tcx, ObligationCause::dummy(), cx.param_env, predicate);
             let infcx = cx.tcx.infer_ctxt().build();
             infcx.predicate_must_hold_modulo_regions(&obligation)
         })
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
index 642a64ae77b6d..c7775313ecd02 100644
--- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_to_owned.rs
@@ -419,7 +419,7 @@ fn can_change_type<'a>(cx: &LateContext<'a>, mut expr: &'a Expr<'a>, mut ty: Ty<
 
                         if trait_predicates.any(|predicate| {
                             let predicate = EarlyBinder(predicate).subst(cx.tcx, new_subst);
-                            let obligation = Obligation::new(ObligationCause::dummy(), cx.param_env, predicate);
+                            let obligation = Obligation::new(cx.tcx, ObligationCause::dummy(), cx.param_env, predicate);
                             !cx.tcx.infer_ctxt().build().predicate_must_hold_modulo_regions(&obligation)
                         }) {
                             return false;
diff --git a/src/tools/clippy/clippy_lints/src/ptr.rs b/src/tools/clippy/clippy_lints/src/ptr.rs
index 0d74c90a834f7..c8c6f32c6c989 100644
--- a/src/tools/clippy/clippy_lints/src/ptr.rs
+++ b/src/tools/clippy/clippy_lints/src/ptr.rs
@@ -695,6 +695,7 @@ fn matches_preds<'tcx>(
             .type_implements_trait(p.def_id, ty, p.substs, cx.param_env)
             .must_apply_modulo_regions(),
         ExistentialPredicate::Projection(p) => infcx.predicate_must_hold_modulo_regions(&Obligation::new(
+            cx.tcx,
             ObligationCause::dummy(),
             cx.param_env,
             cx.tcx.mk_predicate(Binder::bind_with_vars(