Auto merge of #112974 - matthiaskrgr:rollup-hnk7ans, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #112616 (Improve tests on targets without unwinding)
 - #112643 (Always register sized obligation for argument)
 - #112740 (Add link to rustdoc book search chapter in help popover)
 - #112810 (Don't ICE on unnormalized struct tail in layout computation)
 - #112870 (Migrate `item_bounds` to `ty::Clause`)
 - #112925 (Stop hiding const eval limit in external macros)
 - #112960 ([tests/rustdoc] Add `@files` command)
 - #112962 (Fix rustdoc gui tester)

r? `@ghost`
`@rustbot` modify labels: rollup

40 files changed, 265 insertions, 166 deletions

diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 7119510849a..5c365e98f0b 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -705,7 +705,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => tcx
                 .explicit_item_bounds(def_id)
                 .subst_iter_copied(tcx, substs)
-                .find_map(find_fn_kind_from_did),
+                .find_map(|(clause, span)| find_fn_kind_from_did((clause.as_predicate(), span))),
             ty::Closure(_, substs) => match substs.as_closure().kind() {
                 ty::ClosureKind::Fn => Some(hir::Mutability::Not),
                 ty::ClosureKind::FnMut => Some(hir::Mutability::Mut),
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index 1dfe053b215..596c5518086 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -409,9 +409,7 @@ fn fn_sig_suggestion<'tcx>(
         output = if let ty::Alias(_, alias_ty) = *output.kind() {
             tcx.explicit_item_bounds(alias_ty.def_id)
                 .subst_iter_copied(tcx, alias_ty.substs)
-                .find_map(|(bound, _)| {
-                    bound.to_opt_poly_projection_pred()?.no_bound_vars()?.term.ty()
-                })
+                .find_map(|(bound, _)| bound.as_projection_clause()?.no_bound_vars()?.term.ty())
                 .unwrap_or_else(|| {
                     span_bug!(
                         ident.span,
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 51e9b4c4501..814a290178e 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -1086,7 +1086,7 @@ fn check_associated_type_bounds(wfcx: &WfCheckingCtxt<'_, '_>, item: ty::AssocIt
             wfcx.infcx,
             wfcx.param_env,
             wfcx.body_def_id,
-            normalized_bound,
+            normalized_bound.as_predicate(),
             bound_span,
         )
     });
@@ -1562,7 +1562,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
                     self.wfcx.infcx,
                     self.wfcx.param_env,
                     self.wfcx.body_def_id,
-                    bound,
+                    bound.as_predicate(),
                     bound_span,
                 ));
                 // Set the debruijn index back to innermost here, since we already eagerly
diff --git a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
index 5f35678d95d..958313fee6f 100644
--- a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
+++ b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
@@ -19,7 +19,7 @@ fn associated_type_bounds<'tcx>(
     assoc_item_def_id: LocalDefId,
     ast_bounds: &'tcx [hir::GenericBound<'tcx>],
     span: Span,
-) -> &'tcx [(ty::Predicate<'tcx>, Span)] {
+) -> &'tcx [(ty::Clause<'tcx>, Span)] {
     let item_ty = tcx.mk_projection(
         assoc_item_def_id.to_def_id(),
         InternalSubsts::identity_for_item(tcx, assoc_item_def_id),
@@ -33,8 +33,11 @@ fn associated_type_bounds<'tcx>(
     let trait_def_id = tcx.local_parent(assoc_item_def_id);
     let trait_predicates = tcx.trait_explicit_predicates_and_bounds(trait_def_id);
 
-    let bounds_from_parent = trait_predicates.predicates.iter().copied().filter(|(pred, _)| {
-        match pred.kind().skip_binder() {
+    let bounds_from_parent = trait_predicates
+        .predicates
+        .iter()
+        .copied()
+        .filter(|(pred, _)| match pred.kind().skip_binder() {
             ty::PredicateKind::Clause(ty::ClauseKind::Trait(tr)) => tr.self_ty() == item_ty,
             ty::PredicateKind::Clause(ty::ClauseKind::Projection(proj)) => {
                 proj.projection_ty.self_ty() == item_ty
@@ -43,15 +46,10 @@ fn associated_type_bounds<'tcx>(
                 outlives.0 == item_ty
             }
             _ => false,
-        }
-    });
+        })
+        .map(|(pred, span)| (pred.expect_clause(), span));
 
-    let all_bounds = tcx.arena.alloc_from_iter(
-        bounds
-            .clauses()
-            .map(|(clause, span)| (clause.as_predicate(), span))
-            .chain(bounds_from_parent),
-    );
+    let all_bounds = tcx.arena.alloc_from_iter(bounds.clauses().chain(bounds_from_parent));
     debug!(
         "associated_type_bounds({}) = {:?}",
         tcx.def_path_str(assoc_item_def_id.to_def_id()),
@@ -71,7 +69,7 @@ fn opaque_type_bounds<'tcx>(
     ast_bounds: &'tcx [hir::GenericBound<'tcx>],
     item_ty: Ty<'tcx>,
     span: Span,
-) -> &'tcx [(ty::Predicate<'tcx>, Span)] {
+) -> &'tcx [(ty::Clause<'tcx>, Span)] {
     ty::print::with_no_queries!({
         let icx = ItemCtxt::new(tcx, opaque_def_id);
         let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, OnlySelfBounds(false));
@@ -79,15 +77,14 @@ fn opaque_type_bounds<'tcx>(
         icx.astconv().add_implicitly_sized(&mut bounds, item_ty, ast_bounds, None, span);
         debug!(?bounds);
 
-        tcx.arena
-            .alloc_from_iter(bounds.clauses().map(|(clause, span)| (clause.as_predicate(), span)))
+        tcx.arena.alloc_from_iter(bounds.clauses())
     })
 }
 
 pub(super) fn explicit_item_bounds(
     tcx: TyCtxt<'_>,
     def_id: LocalDefId,
-) -> ty::EarlyBinder<&'_ [(ty::Predicate<'_>, Span)]> {
+) -> ty::EarlyBinder<&'_ [(ty::Clause<'_>, Span)]> {
     match tcx.opt_rpitit_info(def_id.to_def_id()) {
         // RPITIT's bounds are the same as opaque type bounds, but with
         // a projection self type.
@@ -139,11 +136,8 @@ pub(super) fn explicit_item_bounds(
 pub(super) fn item_bounds(
     tcx: TyCtxt<'_>,
     def_id: DefId,
-) -> ty::EarlyBinder<&'_ ty::List<ty::Predicate<'_>>> {
+) -> ty::EarlyBinder<&'_ ty::List<ty::Clause<'_>>> {
     tcx.explicit_item_bounds(def_id).map_bound(|bounds| {
-        tcx.mk_predicates_from_iter(util::elaborate(
-            tcx,
-            bounds.iter().map(|&(bound, _span)| bound),
-        ))
+        tcx.mk_clauses_from_iter(util::elaborate(tcx, bounds.iter().map(|&(bound, _span)| bound)))
     })
 }
diff --git a/compiler/rustc_hir_analysis/src/outlives/mod.rs b/compiler/rustc_hir_analysis/src/outlives/mod.rs
index 98f4a8e00ef..48624cefe4d 100644
--- a/compiler/rustc_hir_analysis/src/outlives/mod.rs
+++ b/compiler/rustc_hir_analysis/src/outlives/mod.rs
@@ -3,7 +3,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::subst::GenericArgKind;
-use rustc_middle::ty::{self, CratePredicatesMap, TyCtxt};
+use rustc_middle::ty::{self, CratePredicatesMap, ToPredicate, TyCtxt};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
@@ -17,7 +17,7 @@ pub fn provide(providers: &mut Providers) {
     *providers = Providers { inferred_outlives_of, inferred_outlives_crate, ..*providers };
 }
 
-fn inferred_outlives_of(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[(ty::ClauseKind<'_>, Span)] {
+fn inferred_outlives_of(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[(ty::Clause<'_>, Span)] {
     let id = tcx.hir().local_def_id_to_hir_id(item_def_id);
 
     if matches!(tcx.def_kind(item_def_id), hir::def::DefKind::AnonConst)
@@ -52,7 +52,7 @@ fn inferred_outlives_of(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[(ty::Clau
                 if tcx.has_attr(item_def_id, sym::rustc_outlives) {
                     let mut pred: Vec<String> = predicates
                         .iter()
-                        .map(|(out_pred, _)| match out_pred {
+                        .map(|(out_pred, _)| match out_pred.kind().skip_binder() {
                             ty::ClauseKind::RegionOutlives(p) => p.to_string(),
                             ty::ClauseKind::TypeOutlives(p) => p.to_string(),
                             err => bug!("unexpected clause {:?}", err),
@@ -104,13 +104,15 @@ fn inferred_outlives_crate(tcx: TyCtxt<'_>, (): ()) -> CratePredicatesMap<'_> {
                     |(ty::OutlivesPredicate(kind1, region2), &span)| {
                         match kind1.unpack() {
                             GenericArgKind::Type(ty1) => Some((
-                                ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty1, *region2)),
+                                ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty1, *region2))
+                                    .to_predicate(tcx),
                                 span,
                             )),
                             GenericArgKind::Lifetime(region1) => Some((
                                 ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(
                                     region1, *region2,
-                                )),
+                                ))
+                                .to_predicate(tcx),
                                 span,
                             )),
                             GenericArgKind::Const(_) => {
diff --git a/compiler/rustc_hir_analysis/src/variance/mod.rs b/compiler/rustc_hir_analysis/src/variance/mod.rs
index 8bb9ca2acf2..23d8da88a45 100644
--- a/compiler/rustc_hir_analysis/src/variance/mod.rs
+++ b/compiler/rustc_hir_analysis/src/variance/mod.rs
@@ -162,28 +162,25 @@ fn variance_of_opaque(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[ty::Varianc
         // which thus mentions `'a` and should thus accept hidden types that borrow 'a
         // instead of requiring an additional `+ 'a`.
         match pred.kind().skip_binder() {
-            ty::PredicateKind::Clause(ty::ClauseKind::Trait(ty::TraitPredicate {
+            ty::ClauseKind::Trait(ty::TraitPredicate {
                 trait_ref: ty::TraitRef { def_id: _, substs, .. },
                 constness: _,
                 polarity: _,
-            })) => {
+            }) => {
                 for subst in &substs[1..] {
                     subst.visit_with(&mut collector);
                 }
             }
-            ty::PredicateKind::Clause(ty::ClauseKind::Projection(ty::ProjectionPredicate {
+            ty::ClauseKind::Projection(ty::ProjectionPredicate {
                 projection_ty: ty::AliasTy { substs, .. },
                 term,
-            })) => {
+            }) => {
                 for subst in &substs[1..] {
                     subst.visit_with(&mut collector);
                 }
                 term.visit_with(&mut collector);
             }
-            ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(
-                _,
-                region,
-            ))) => {
+            ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(_, region)) => {
                 region.visit_with(&mut collector);
             }
             _ => {
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index a07580fe72d..c7fa27da1ac 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -536,33 +536,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
 
                 for ty in [first_ty, second_ty] {
-                    for (pred, _) in self
+                    for (clause, _) in self
                         .tcx
                         .explicit_item_bounds(rpit_def_id)
                         .subst_iter_copied(self.tcx, substs)
                     {
-                        let pred = pred.kind().rebind(match pred.kind().skip_binder() {
-                            ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_pred)) => {
+                        let pred = clause.kind().rebind(match clause.kind().skip_binder() {
+                            ty::ClauseKind::Trait(trait_pred) => {
                                 // FIXME(rpitit): This will need to be fixed when we move to associated types
                                 assert!(matches!(
                                     *trait_pred.trait_ref.self_ty().kind(),
                                     ty::Alias(_, ty::AliasTy { def_id, substs: alias_substs, .. })
                                     if def_id == rpit_def_id && substs == alias_substs
                                 ));
-                                ty::PredicateKind::Clause(ty::ClauseKind::Trait(
-                                    trait_pred.with_self_ty(self.tcx, ty),
-                                ))
+                                ty::ClauseKind::Trait(trait_pred.with_self_ty(self.tcx, ty))
                             }
-                            ty::PredicateKind::Clause(ty::ClauseKind::Projection(
-                                mut proj_pred,
-                            )) => {
+                            ty::ClauseKind::Projection(mut proj_pred) => {
                                 assert!(matches!(
                                     *proj_pred.projection_ty.self_ty().kind(),
                                     ty::Alias(_, ty::AliasTy { def_id, substs: alias_substs, .. })
                                     if def_id == rpit_def_id && substs == alias_substs
                                 ));
                                 proj_pred = proj_pred.with_self_ty(self.tcx, ty);
-                                ty::PredicateKind::Clause(ty::ClauseKind::Projection(proj_pred))
+                                ty::ClauseKind::Projection(proj_pred)
                             }
                             _ => continue,
                         });
diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs
index 69ccbf0b58f..0a1b639af51 100644
--- a/compiler/rustc_hir_typeck/src/check.rs
+++ b/compiler/rustc_hir_typeck/src/check.rs
@@ -92,10 +92,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         fcx.check_pat_top(&param.pat, param_ty, ty_span, None);
 
         // Check that argument is Sized.
-        // The check for a non-trivial pattern is a hack to avoid duplicate warnings
-        // for simple cases like `fn foo(x: Trait)`,
-        // where we would error once on the parameter as a whole, and once on the binding `x`.
-        if param.pat.simple_ident().is_none() && !params_can_be_unsized {
+        if !params_can_be_unsized {
             fcx.require_type_is_sized(
                 param_ty,
                 param.pat.span,
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index 94b37fb3450..c64b64e925a 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -174,7 +174,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => self
                 .deduce_closure_signature_from_predicates(
                     expected_ty,
-                    self.tcx.explicit_item_bounds(def_id).subst_iter_copied(self.tcx, substs),
+                    self.tcx
+                        .explicit_item_bounds(def_id)
+                        .subst_iter_copied(self.tcx, substs)
+                        .map(|(c, s)| (c.as_predicate(), s)),
                 ),
             ty::Dynamic(ref object_type, ..) => {
                 let sig = object_type.projection_bounds().find_map(|pb| {
@@ -717,13 +720,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .tcx
                 .explicit_item_bounds(def_id)
                 .subst_iter_copied(self.tcx, substs)
-                .find_map(|(p, s)| get_future_output(p, s))?,
+                .find_map(|(p, s)| get_future_output(p.as_predicate(), s))?,
             ty::Error(_) => return None,
             ty::Alias(ty::Projection, proj) if self.tcx.is_impl_trait_in_trait(proj.def_id) => self
                 .tcx
                 .explicit_item_bounds(proj.def_id)
                 .subst_iter_copied(self.tcx, proj.substs)
-                .find_map(|(p, s)| get_future_output(p, s))?,
+                .find_map(|(p, s)| get_future_output(p.as_predicate(), s))?,
             _ => span_bug!(
                 self.tcx.def_span(expr_def_id),
                 "async fn generator return type not an inference variable: {ret_ty}"
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
index dabe7749cb6..fdbb153ec7d 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
@@ -577,7 +577,7 @@ fn check_must_not_suspend_ty<'tcx>(
             let mut has_emitted = false;
             for &(predicate, _) in fcx.tcx.explicit_item_bounds(def).skip_binder() {
                 // We only look at the `DefId`, so it is safe to skip the binder here.
-                if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(ref poly_trait_predicate)) =
+                if let ty::ClauseKind::Trait(ref poly_trait_predicate) =
                     predicate.kind().skip_binder()
                 {
                     let def_id = poly_trait_predicate.trait_ref.def_id;
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 63370eec10b..15213c4b023 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -408,9 +408,9 @@ impl<'tcx> InferCtxt<'tcx> {
                 predicate
                     .kind()
                     .map_bound(|kind| match kind {
-                        ty::PredicateKind::Clause(ty::ClauseKind::Projection(
-                            projection_predicate,
-                        )) if projection_predicate.projection_ty.def_id == item_def_id => {
+                        ty::ClauseKind::Projection(projection_predicate)
+                            if projection_predicate.projection_ty.def_id == item_def_id =>
+                        {
                             projection_predicate.term.ty()
                         }
                         _ => None,
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs
index 3cb1788dc19..0390c868c1b 100644
--- a/compiler/rustc_infer/src/infer/opaque_types.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types.rs
@@ -649,9 +649,7 @@ impl<'tcx> InferCtxt<'tcx> {
                 ct_op: |ct| ct,
             });
 
-            if let ty::PredicateKind::Clause(ty::ClauseKind::Projection(projection)) =
-                predicate.kind().skip_binder()
-            {
+            if let ty::ClauseKind::Projection(projection) = predicate.kind().skip_binder() {
                 if projection.term.references_error() {
                     // No point on adding any obligations since there's a type error involved.
                     obligations.clear();
diff --git a/compiler/rustc_infer/src/infer/outlives/verify.rs b/compiler/rustc_infer/src/infer/outlives/verify.rs
index 59ae2ce6c60..871171f9447 100644
--- a/compiler/rustc_infer/src/infer/outlives/verify.rs
+++ b/compiler/rustc_infer/src/infer/outlives/verify.rs
@@ -296,7 +296,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         trace!("{:#?}", bounds.skip_binder());
         bounds
             .subst_iter(tcx, alias_ty.substs)
-            .filter_map(|p| p.to_opt_type_outlives())
+            .filter_map(|p| p.as_type_outlives_clause())
             .filter_map(|p| p.no_bound_vars())
             .map(|OutlivesPredicate(_, r)| r)
     }
diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index 00d4934b749..26919872952 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -167,13 +167,33 @@ impl<'tcx> Elaboratable<'tcx> for (ty::Predicate<'tcx>, Span) {
     }
 }
 
+impl<'tcx> Elaboratable<'tcx> for (ty::Clause<'tcx>, Span) {
+    fn predicate(&self) -> ty::Predicate<'tcx> {
+        self.0.as_predicate()
+    }
+
+    fn child(&self, predicate: ty::Predicate<'tcx>) -> Self {
+        (predicate.expect_clause(), self.1)
+    }
+
+    fn child_with_derived_cause(
+        &self,
+        predicate: ty::Predicate<'tcx>,
+        _span: Span,
+        _parent_trait_pred: ty::PolyTraitPredicate<'tcx>,
+        _index: usize,
+    ) -> Self {
+        (predicate.expect_clause(), self.1)
+    }
+}
+
 impl<'tcx> Elaboratable<'tcx> for ty::Clause<'tcx> {
     fn predicate(&self) -> ty::Predicate<'tcx> {
         self.as_predicate()
     }
 
     fn child(&self, predicate: ty::Predicate<'tcx>) -> Self {
-        predicate.as_clause().unwrap()
+        predicate.expect_clause()
     }
 
     fn child_with_derived_cause(
@@ -183,7 +203,7 @@ impl<'tcx> Elaboratable<'tcx> for ty::Clause<'tcx> {
         _parent_trait_pred: ty::PolyTraitPredicate<'tcx>,
         _index: usize,
     ) -> Self {
-        predicate.as_clause().unwrap()
+        predicate.expect_clause()
     }
 }
 
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 9fb83bec993..5c5ec452850 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -1984,12 +1984,12 @@ declare_lint_pass!(ExplicitOutlivesRequirements => [EXPLICIT_OUTLIVES_REQUIREMEN
 
 impl ExplicitOutlivesRequirements {
     fn lifetimes_outliving_lifetime<'tcx>(
-        inferred_outlives: &'tcx [(ty::ClauseKind<'tcx>, Span)],
+        inferred_outlives: &'tcx [(ty::Clause<'tcx>, Span)],
         def_id: DefId,
     ) -> Vec<ty::Region<'tcx>> {
         inferred_outlives
             .iter()
-            .filter_map(|(clause, _)| match *clause {
+            .filter_map(|(clause, _)| match clause.kind().skip_binder() {
                 ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => match *a {
                     ty::ReEarlyBound(ebr) if ebr.def_id == def_id => Some(b),
                     _ => None,
@@ -2000,12 +2000,12 @@ impl ExplicitOutlivesRequirements {
     }
 
     fn lifetimes_outliving_type<'tcx>(
-        inferred_outlives: &'tcx [(ty::ClauseKind<'tcx>, Span)],
+        inferred_outlives: &'tcx [(ty::Clause<'tcx>, Span)],
         index: u32,
     ) -> Vec<ty::Region<'tcx>> {
         inferred_outlives
             .iter()
-            .filter_map(|(clause, _)| match *clause {
+            .filter_map(|(clause, _)| match clause.kind().skip_binder() {
                 ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(a, b)) => {
                     a.is_param(index).then_some(b)
                 }
diff --git a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
index 61c23b4c255..63a56806a45 100644
--- a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
+++ b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
@@ -78,7 +78,7 @@ impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound {
             // Liberate bound regions in the predicate since we
             // don't actually care about lifetimes in this check.
             let predicate = cx.tcx.liberate_late_bound_regions(def_id, pred.kind());
-            let ty::PredicateKind::Clause(ty::ClauseKind::Projection(proj)) = predicate else {
+            let ty::ClauseKind::Projection(proj) = predicate else {
                 continue;
             };
             // Only check types, since those are the only things that may
@@ -133,7 +133,7 @@ impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound {
                     let add_bound = match (proj_term.kind(), assoc_pred.kind().skip_binder()) {
                         (
                             ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }),
-                            ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_pred)),
+                            ty::ClauseKind::Trait(trait_pred),
                         ) => Some(AddBound {
                             suggest_span: cx.tcx.def_span(*def_id).shrink_to_hi(),
                             trait_ref: trait_pred.print_modifiers_and_trait_path(),
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index e0033c48edb..5015b751eee 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -289,9 +289,8 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                         .filter_only_self()
                         .find_map(|(pred, _span)| {
                             // We only look at the `DefId`, so it is safe to skip the binder here.
-                            if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(
-                                ref poly_trait_predicate,
-                            )) = pred.kind().skip_binder()
+                            if let ty::ClauseKind::Trait(ref poly_trait_predicate) =
+                                pred.kind().skip_binder()
                             {
                                 let def_id = poly_trait_predicate.trait_ref.def_id;
 
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 53ece08ac3d..cbb4458d1d4 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -3464,7 +3464,8 @@ declare_lint! {
     /// out an update in your own time.
     pub LONG_RUNNING_CONST_EVAL,
     Deny,
-    "detects long const eval operations"
+    "detects long const eval operations",
+    report_in_external_macro
 }
 
 declare_lint! {
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 21cbab54293..90014bd9267 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -25,7 +25,7 @@ use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc_middle::ty::codec::TyDecoder;
 use rustc_middle::ty::fast_reject::SimplifiedType;
 use rustc_middle::ty::GeneratorDiagnosticData;
-use rustc_middle::ty::{self, ParameterizedOverTcx, Predicate, Ty, TyCtxt, Visibility};
+use rustc_middle::ty::{self, ParameterizedOverTcx, Ty, TyCtxt, Visibility};
 use rustc_serialize::opaque::MemDecoder;
 use rustc_serialize::{Decodable, Decoder};
 use rustc_session::cstore::{
@@ -642,6 +642,12 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [(ty::Predicate<'tcx
     }
 }
 
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [(ty::Clause<'tcx>, Span)] {
+    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Self {
+        ty::codec::RefDecodable::decode(d)
+    }
+}
+
 impl<'a, 'tcx, T> Decodable<DecodeContext<'a, 'tcx>> for LazyValue<T> {
     fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Self {
         decoder.read_lazy()
@@ -854,7 +860,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self,
         index: DefIndex,
         tcx: TyCtxt<'tcx>,
-    ) -> ty::EarlyBinder<&'tcx [(Predicate<'tcx>, Span)]> {
+    ) -> ty::EarlyBinder<&'tcx [(ty::Clause<'tcx>, Span)]> {
         let lazy = self.root.tables.explicit_item_bounds.get(self, index);
         let output = if lazy.is_default() {
             &mut []
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index d11308196ea..9cffd96f4a3 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -375,8 +375,8 @@ define_tables! {
     is_type_alias_impl_trait: Table<DefIndex, bool>,
     attr_flags: Table<DefIndex, AttrFlags>,
     def_path_hashes: Table<DefIndex, DefPathHash>,
-    explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Predicate<'static>, Span)>>,
-    inferred_outlives_of: Table<DefIndex, LazyArray<(ty::ClauseKind<'static>, Span)>>,
+    explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
+    inferred_outlives_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
     associated_types_for_impl_traits_in_associated_fn: Table<DefIndex, LazyArray<DefId>>,
     opt_rpitit_info: Table<DefIndex, Option<LazyValue<ty::ImplTraitInTraitData>>>,
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 440dede1700..5d6a477b9ad 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -346,7 +346,7 @@ rustc_queries! {
     /// `key` is the `DefId` of the associated type or opaque type.
     ///
     /// Bounds from the parent (e.g. with nested impl trait) are not included.
-    query explicit_item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx [(ty::Predicate<'tcx>, Span)]> {
+    query explicit_item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx [(ty::Clause<'tcx>, Span)]> {
         desc { |tcx| "finding item bounds for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
@@ -373,7 +373,7 @@ rustc_queries! {
     /// ```
     ///
     /// Bounds from the parent (e.g. with nested impl trait) are not included.
-    query item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
+    query item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Clause<'tcx>>> {
         desc { |tcx| "elaborating item bounds for `{}`", tcx.def_path_str(key) }
     }
 
@@ -647,7 +647,7 @@ rustc_queries! {
 
     /// Returns the inferred outlives predicates (e.g., for `struct
     /// Foo<'a, T> { x: &'a T }`, this would return `T: 'a`).
-    query inferred_outlives_of(key: DefId) -> &'tcx [(ty::ClauseKind<'tcx>, Span)] {
+    query inferred_outlives_of(key: DefId) -> &'tcx [(ty::Clause<'tcx>, Span)] {
         desc { |tcx| "computing inferred outlives predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
diff --git a/compiler/rustc_middle/src/query/on_disk_cache.rs b/compiler/rustc_middle/src/query/on_disk_cache.rs
index 105667ba1e6..220118ae5cc 100644
--- a/compiler/rustc_middle/src/query/on_disk_cache.rs
+++ b/compiler/rustc_middle/src/query/on_disk_cache.rs
@@ -798,7 +798,7 @@ impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::Predicate<'tcx>
     }
 }
 
-impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::ClauseKind<'tcx>, Span)] {
+impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::Clause<'tcx>, Span)] {
     #[inline]
     fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Self {
         RefDecodable::decode(d)
diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index ff8cd904ef8..248251e1ef5 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -128,6 +128,12 @@ impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for ty::Predicate<'tcx>
     }
 }
 
+impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for ty::Clause<'tcx> {
+    fn encode(&self, e: &mut E) {
+        self.as_predicate().encode(e);
+    }
+}
+
 impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for ty::Region<'tcx> {
     fn encode(&self, e: &mut E) {
         self.kind().encode(e);
@@ -241,6 +247,13 @@ impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for ty::Predicate<'tcx>
     }
 }
 
+impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for ty::Clause<'tcx> {
+    fn decode(decoder: &mut D) -> ty::Clause<'tcx> {
+        let pred: ty::Predicate<'tcx> = Decodable::decode(decoder);
+        pred.expect_clause()
+    }
+}
+
 impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for SubstsRef<'tcx> {
     fn decode(decoder: &mut D) -> Self {
         let len = decoder.read_usize();
@@ -365,9 +378,7 @@ impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D>
     }
 }
 
-impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D>
-    for [(ty::ClauseKind<'tcx>, Span)]
-{
+impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> RefDecodable<'tcx, D> for [(ty::Clause<'tcx>, Span)] {
     fn decode(decoder: &mut D) -> &'tcx Self {
         decoder.interner().arena.alloc_from_iter(
             (0..decoder.read_usize()).map(|_| Decodable::decode(decoder)).collect::<Vec<_>>(),
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 2b4f69167bf..b2ada4882e1 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -25,10 +25,10 @@ use crate::traits::solve::{
     ExternalConstraints, ExternalConstraintsData, PredefinedOpaques, PredefinedOpaquesData,
 };
 use crate::ty::{
-    self, AdtDef, AdtDefData, AdtKind, Binder, Const, ConstData, FloatTy, FloatVar, FloatVid,
-    GenericParamDefKind, ImplPolarity, InferTy, IntTy, IntVar, IntVid, List, ParamConst, ParamTy,
-    PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, Region, RegionKind, ReprOptions,
-    TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut, UintTy, Visibility,
+    self, AdtDef, AdtDefData, AdtKind, Binder, Clause, Const, ConstData, FloatTy, FloatVar,
+    FloatVid, GenericParamDefKind, ImplPolarity, InferTy, IntTy, IntVar, IntVid, List, ParamConst,
+    ParamTy, PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, Region, RegionKind,
+    ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut, UintTy, Visibility,
 };
 use crate::ty::{GenericArg, InternalSubsts, SubstsRef};
 use rustc_ast::{self as ast, attr};
@@ -141,7 +141,9 @@ pub struct CtxtInterners<'tcx> {
     region: InternedSet<'tcx, RegionKind<'tcx>>,
     poly_existential_predicates: InternedSet<'tcx, List<PolyExistentialPredicate<'tcx>>>,
     predicate: InternedSet<'tcx, WithCachedTypeInfo<ty::Binder<'tcx, PredicateKind<'tcx>>>>,
+    // FIXME(clause): remove this when all usages are moved to predicate
     predicates: InternedSet<'tcx, List<Predicate<'tcx>>>,
+    clauses: InternedSet<'tcx, List<Clause<'tcx>>>,
     projs: InternedSet<'tcx, List<ProjectionKind>>,
     place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
     const_: InternedSet<'tcx, ConstData<'tcx>>,
@@ -167,6 +169,7 @@ impl<'tcx> CtxtInterners<'tcx> {
             canonical_var_infos: Default::default(),
             predicate: Default::default(),
             predicates: Default::default(),
+            clauses: Default::default(),
             projs: Default::default(),
             place_elems: Default::default(),
             const_: Default::default(),
@@ -1533,6 +1536,7 @@ slice_interners!(
     canonical_var_infos: pub mk_canonical_var_infos(CanonicalVarInfo<'tcx>),
     poly_existential_predicates: intern_poly_existential_predicates(PolyExistentialPredicate<'tcx>),
     predicates: intern_predicates(Predicate<'tcx>),
+    clauses: intern_clauses(Clause<'tcx>),
     projs: pub mk_projs(ProjectionKind),
     place_elems: pub mk_place_elems(PlaceElem<'tcx>),
     bound_variable_kinds: pub mk_bound_variable_kinds(ty::BoundVariableKind),
@@ -1564,7 +1568,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let future_trait = self.require_lang_item(LangItem::Future, None);
 
         self.explicit_item_bounds(def_id).skip_binder().iter().any(|&(predicate, _)| {
-            let ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_predicate)) = predicate.kind().skip_binder() else {
+            let ty::ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder() else {
                 return false;
             };
             trait_predicate.trait_ref.def_id == future_trait
@@ -2084,6 +2088,13 @@ impl<'tcx> TyCtxt<'tcx> {
         self.intern_predicates(preds)
     }
 
+    pub fn mk_clauses(self, preds: &[Clause<'tcx>]) -> &'tcx List<Clause<'tcx>> {
+        // FIXME consider asking the input slice to be sorted to avoid
+        // re-interning permutations, in which case that would be asserted
+        // here.
+        self.intern_clauses(preds)
+    }
+
     pub fn mk_const_list_from_iter<I, T>(self, iter: I) -> T::Output
     where
         I: Iterator<Item = T>,
@@ -2135,6 +2146,14 @@ impl<'tcx> TyCtxt<'tcx> {
         T::collect_and_apply(iter, |xs| self.mk_predicates(xs))
     }
 
+    pub fn mk_clauses_from_iter<I, T>(self, iter: I) -> T::Output
+    where
+        I: Iterator<Item = T>,
+        T: CollectAndApply<Clause<'tcx>, &'tcx List<Clause<'tcx>>>,
+    {
+        T::collect_and_apply(iter, |xs| self.mk_clauses(xs))
+    }
+
     pub fn mk_type_list_from_iter<I, T>(self, iter: I) -> T::Output
     where
         I: Iterator<Item = T>,
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index c5a306fdf1f..c1d6856d33c 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -318,7 +318,13 @@ impl<'tcx> SizeSkeleton<'tcx> {
             Ok(layout) => {
                 return Ok(SizeSkeleton::Known(layout.size));
             }
-            Err(err) => err,
+            Err(err @ LayoutError::Unknown(_)) => err,
+            // We can't extract SizeSkeleton info from other layout errors
+            Err(
+                e @ LayoutError::Cycle
+                | e @ LayoutError::SizeOverflow(_)
+                | e @ LayoutError::NormalizationFailure(..),
+            ) => return Err(e),
         };
 
         match *ty.kind() {
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index cd459130827..0e604fdf6f4 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -602,6 +602,24 @@ impl<'tcx> Clause<'tcx> {
             None
         }
     }
+
+    pub fn as_type_outlives_clause(self) -> Option<Binder<'tcx, TypeOutlivesPredicate<'tcx>>> {
+        let clause = self.kind();
+        if let ty::ClauseKind::TypeOutlives(o) = clause.skip_binder() {
+            Some(clause.rebind(o))
+        } else {
+            None
+        }
+    }
+
+    pub fn as_region_outlives_clause(self) -> Option<Binder<'tcx, RegionOutlivesPredicate<'tcx>>> {
+        let clause = self.kind();
+        if let ty::ClauseKind::RegionOutlives(o) = clause.skip_binder() {
+            Some(clause.rebind(o))
+        } else {
+            None
+        }
+    }
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
@@ -713,7 +731,7 @@ pub struct CratePredicatesMap<'tcx> {
     /// predicate of its outlive bounds. If an item has no outlives
     /// bounds, it will have no entry.
     // FIXME(clause): should this be a `Clause`?
-    pub predicates: FxHashMap<DefId, &'tcx [(ClauseKind<'tcx>, Span)]>,
+    pub predicates: FxHashMap<DefId, &'tcx [(Clause<'tcx>, Span)]>,
 }
 
 impl<'tcx> Predicate<'tcx> {
@@ -1243,7 +1261,21 @@ impl<'tcx> ToPredicate<'tcx> for ClauseKind<'tcx> {
 impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, ClauseKind<'tcx>> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
-        tcx.mk_predicate(self.map_bound(|clause| ty::PredicateKind::Clause(clause)))
+        tcx.mk_predicate(self.map_bound(ty::PredicateKind::Clause))
+    }
+}
+
+impl<'tcx> ToPredicate<'tcx> for Clause<'tcx> {
+    #[inline(always)]
+    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+        self.as_predicate()
+    }
+}
+
+impl<'tcx> ToPredicate<'tcx, Clause<'tcx>> for ClauseKind<'tcx> {
+    #[inline(always)]
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Clause<'tcx> {
+        tcx.mk_predicate(Binder::dummy(ty::PredicateKind::Clause(self))).expect_clause()
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index 97d13822adc..cc2b26a5e14 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -128,6 +128,7 @@ parameterized_over_tcx! {
     ty::TraitRef,
     ty::Const,
     ty::Predicate,
+    ty::Clause,
     ty::ClauseKind,
     ty::GeneratorDiagnosticData,
 }
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index fdcc608bf8e..7afda73862d 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -928,7 +928,7 @@ pub trait PrettyPrinter<'tcx>:
             let bound_predicate = predicate.kind();
 
             match bound_predicate.skip_binder() {
-                ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) => {
+                ty::ClauseKind::Trait(pred) => {
                     let trait_ref = bound_predicate.rebind(pred.trait_ref);
 
                     // Don't print + Sized, but rather + ?Sized if absent.
@@ -939,7 +939,7 @@ pub trait PrettyPrinter<'tcx>:
 
                     self.insert_trait_and_projection(trait_ref, None, &mut traits, &mut fn_traits);
                 }
-                ty::PredicateKind::Clause(ty::ClauseKind::Projection(pred)) => {
+                ty::ClauseKind::Projection(pred) => {
                     let proj_ref = bound_predicate.rebind(pred);
                     let trait_ref = proj_ref.required_poly_trait_ref(tcx);
 
@@ -953,7 +953,7 @@ pub trait PrettyPrinter<'tcx>:
                         &mut fn_traits,
                     );
                 }
-                ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(outlives)) => {
+                ty::ClauseKind::TypeOutlives(outlives) => {
                     lifetimes.push(outlives.1);
                 }
                 _ => {}
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index e53e1e0a54c..959bf032a83 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -666,10 +666,7 @@ impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ty::Clause<'tcx> {
         self,
         folder: &mut F,
     ) -> Result<Self, F::Error> {
-        Ok(folder
-            .try_fold_predicate(self.as_predicate())?
-            .as_clause()
-            .expect("no sensible folder would do this"))
+        Ok(folder.try_fold_predicate(self.as_predicate())?.expect_clause())
     }
 }
 
@@ -713,6 +710,15 @@ impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<ty::Predicate<'tcx>> {
     }
 }
 
+impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<ty::Clause<'tcx>> {
+    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
+        self,
+        folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        ty::util::fold_list(self, folder, |tcx, v| tcx.mk_clauses(v))
+    }
+}
+
 impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ty::Const<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
         self,
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index 9f58cce2769..029fb2e9ba0 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -1824,7 +1824,7 @@ fn check_must_not_suspend_ty<'tcx>(
             let mut has_emitted = false;
             for &(predicate, _) in tcx.explicit_item_bounds(def).skip_binder() {
                 // We only look at the `DefId`, so it is safe to skip the binder here.
-                if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(ref poly_trait_predicate)) =
+                if let ty::ClauseKind::Trait(ref poly_trait_predicate) =
                     predicate.kind().skip_binder()
                 {
                     let def_id = poly_trait_predicate.trait_ref.def_id;
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index b897a6198e3..8a848e5db62 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -114,6 +114,12 @@ trait DefIdVisitor<'tcx> {
     ) -> ControlFlow<Self::BreakTy> {
         self.skeleton().visit_predicates(predicates)
     }
+    fn visit_clauses(
+        &mut self,
+        predicates: &[(ty::Clause<'tcx>, Span)],
+    ) -> ControlFlow<Self::BreakTy> {
+        self.skeleton().visit_clauses(predicates)
+    }
 }
 
 struct DefIdVisitorSkeleton<'v, 'tcx, V: ?Sized> {
@@ -159,42 +165,23 @@ where
         }
     }
 
-    fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> ControlFlow<V::BreakTy> {
-        match predicate.kind().skip_binder() {
-            ty::PredicateKind::Clause(ty::ClauseKind::Trait(ty::TraitPredicate {
-                trait_ref,
-                constness: _,
-                polarity: _,
-            })) => self.visit_trait(trait_ref),
-            ty::PredicateKind::Clause(ty::ClauseKind::Projection(ty::ProjectionPredicate {
-                projection_ty,
-                term,
-            })) => {
+    fn visit_clause(&mut self, clause: ty::Clause<'tcx>) -> ControlFlow<V::BreakTy> {
+        match clause.kind().skip_binder() {
+            ty::ClauseKind::Trait(ty::TraitPredicate { trait_ref, constness: _, polarity: _ }) => {
+                self.visit_trait(trait_ref)
+            }
+            ty::ClauseKind::Projection(ty::ProjectionPredicate { projection_ty, term }) => {
                 term.visit_with(self)?;
                 self.visit_projection_ty(projection_ty)
             }
-            ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(
-                ty,
-                _region,
-            ))) => ty.visit_with(self),
-            ty::PredicateKind::Clause(ty::ClauseKind::RegionOutlives(..)) => {
-                ControlFlow::Continue(())
-            }
-            ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
+            ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty, _region)) => ty.visit_with(self),
+            ty::ClauseKind::RegionOutlives(..) => ControlFlow::Continue(()),
+            ty::ClauseKind::ConstArgHasType(ct, ty) => {
                 ct.visit_with(self)?;
                 ty.visit_with(self)
             }
-            ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(ct)) => ct.visit_with(self),
-            ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(arg)) => arg.visit_with(self),
-
-            ty::PredicateKind::ObjectSafe(_)
-            | ty::PredicateKind::ClosureKind(_, _, _)
-            | ty::PredicateKind::Subtype(_)
-            | ty::PredicateKind::Coerce(_)
-            | ty::PredicateKind::ConstEquate(_, _)
-            | ty::PredicateKind::TypeWellFormedFromEnv(_)
-            | ty::PredicateKind::Ambiguous
-            | ty::PredicateKind::AliasRelate(..) => bug!("unexpected predicate: {:?}", predicate),
+            ty::ClauseKind::ConstEvaluatable(ct) => ct.visit_with(self),
+            ty::ClauseKind::WellFormed(arg) => arg.visit_with(self),
         }
     }
 
@@ -203,7 +190,16 @@ where
         predicates: ty::GenericPredicates<'tcx>,
     ) -> ControlFlow<V::BreakTy> {
         let ty::GenericPredicates { parent: _, predicates } = predicates;
-        predicates.iter().try_for_each(|&(predicate, _span)| self.visit_predicate(predicate))
+        predicates.iter().try_for_each(|&(predicate, _span)| {
+            let clause = predicate
+                .as_clause()
+                .unwrap_or_else(|| bug!("unexpected predicate: {:?}", predicate));
+            self.visit_clause(clause)
+        })
+    }
+
+    fn visit_clauses(&mut self, clauses: &[(ty::Clause<'tcx>, Span)]) -> ControlFlow<V::BreakTy> {
+        clauses.iter().try_for_each(|&(clause, _span)| self.visit_clause(clause))
     }
 }
 
@@ -307,10 +303,7 @@ where
                     // through the trait list (default type visitor doesn't visit those traits).
                     // All traits in the list are considered the "primary" part of the type
                     // and are visited by shallow visitors.
-                    self.visit_predicates(ty::GenericPredicates {
-                        parent: None,
-                        predicates: tcx.explicit_item_bounds(def_id).skip_binder(),
-                    })?;
+                    self.visit_clauses(tcx.explicit_item_bounds(def_id).skip_binder())?;
                 }
             }
             // These types don't have their own def-ids (but may have subcomponents
@@ -1814,10 +1807,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
 
     fn bounds(&mut self) -> &mut Self {
         self.in_primary_interface = false;
-        self.visit_predicates(ty::GenericPredicates {
-            parent: None,
-            predicates: self.tcx.explicit_item_bounds(self.item_def_id).skip_binder(),
-        });
+        self.visit_clauses(self.tcx.explicit_item_bounds(self.item_def_id).skip_binder());
         self
     }
 
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index f2a39faf383..cde8a52cdec 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -522,13 +522,11 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
         for assumption in self.tcx().item_bounds(alias_ty.def_id).subst(self.tcx(), alias_ty.substs)
         {
-            if let Some(clause) = assumption.as_clause() {
-                match G::consider_alias_bound_candidate(self, goal, clause) {
-                    Ok(result) => {
-                        candidates.push(Candidate { source: CandidateSource::AliasBound, result })
-                    }
-                    Err(NoSolution) => (),
+            match G::consider_alias_bound_candidate(self, goal, assumption) {
+                Ok(result) => {
+                    candidates.push(Candidate { source: CandidateSource::AliasBound, result })
                 }
+                Err(NoSolution) => (),
             }
         }
     }
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
index 97b86a06c8c..439cf788ab4 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
@@ -353,7 +353,11 @@ pub(in crate::solve) fn predicates_for_object_candidate<'tcx>(
         // FIXME(associated_const_equality): Also add associated consts to
         // the requirements here.
         if item.kind == ty::AssocKind::Type {
-            requirements.extend(tcx.item_bounds(item.def_id).subst(tcx, trait_ref.substs));
+            requirements.extend(
+                tcx.item_bounds(item.def_id)
+                    .subst_iter(tcx, trait_ref.substs)
+                    .map(|clause| clause.as_predicate()),
+            );
         }
     }
 
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 dba6ffc4c96..71d2380f234 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1157,7 +1157,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
                 ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
                     self.tcx.item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
-                        if let ty::PredicateKind::Clause(ty::ClauseKind::Projection(proj)) = pred.kind().skip_binder()
+                        if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
                         && Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
                         // args tuple will always be substs[1]
                         && let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 499745473a2..df93c4d45dc 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -271,7 +271,7 @@ fn bounds_reference_self(tcx: TyCtxt<'_>, trait_def_id: DefId) -> SmallVec<[Span
         .in_definition_order()
         .filter(|item| item.kind == ty::AssocKind::Type)
         .flat_map(|item| tcx.explicit_item_bounds(item.def_id).subst_identity_iter_copied())
-        .filter_map(|pred_span| predicate_references_self(tcx, pred_span))
+        .filter_map(|(clause, span)| predicate_references_self(tcx, (clause.as_predicate(), span)))
         .collect()
 }
 
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 81b1ecc0d88..2a78c5befa4 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -1585,7 +1585,7 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>(
         obligation,
         candidate_set,
         ProjectionCandidate::TraitDef,
-        bounds.iter(),
+        bounds.iter().map(|clause| clause.as_predicate()),
         true,
     );
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 3c356978d5c..a50af417a44 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -170,7 +170,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let candidate_predicate = tcx.item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs);
         let candidate = candidate_predicate
-            .to_opt_poly_trait_pred()
+            .as_trait_clause()
             .expect("projection candidate is not a trait predicate")
             .map_bound(|t| t.trait_ref);
         let mut obligations = Vec::new();
@@ -631,7 +631,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         let assoc_ty_substs = tcx.mk_substs(&substs);
                         let bound =
                             bound.map_bound(|b| b.kind().skip_binder()).subst(tcx, assoc_ty_substs);
-                        tcx.mk_predicate(ty::Binder::bind_with_vars(bound, bound_vars))
+                        ty::Binder::bind_with_vars(bound, bound_vars).to_predicate(tcx)
                     };
                 let normalized_bound = normalize_with_depth_to(
                     self,
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 0f0e3f1f16a..0a8b7b688e7 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1668,9 +1668,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .enumerate()
             .filter_map(|(idx, bound)| {
                 let bound_predicate = bound.kind();
-                if let ty::PredicateKind::Clause(ty::ClauseKind::Trait(pred)) =
-                    bound_predicate.skip_binder()
-                {
+                if let ty::ClauseKind::Trait(pred) = bound_predicate.skip_binder() {
                     let bound = bound_predicate.rebind(pred.trait_ref);
                     if self.infcx.probe(|_| {
                         match self.match_normalize_trait_ref(
diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
index 38f94c38861..7e64cbdf54a 100644
--- a/compiler/rustc_traits/src/chalk/db.rs
+++ b/compiler/rustc_traits/src/chalk/db.rs
@@ -54,7 +54,9 @@ impl<'tcx> RustIrDatabase<'tcx> {
             .tcx
             .explicit_item_bounds(def_id)
             .subst_iter_copied(self.interner.tcx, &bound_vars)
-            .filter_map(|(bound, _)| LowerInto::<Option<_>>::lower_into(bound, self.interner))
+            .filter_map(|(bound, _)| {
+                LowerInto::<Option<_>>::lower_into(bound.as_predicate(), self.interner)
+            })
             .collect()
     }
 }
@@ -520,7 +522,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
                 .filter_map(|bound| {
                     LowerInto::<
                     Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>
-                >::lower_into(bound, self.interner)
+                >::lower_into(bound.as_predicate(), self.interner)
                 })
                 .collect();
 
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index f48bba24132..c8c2c8286b0 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -145,17 +145,35 @@ fn layout_of_uncached<'tcx>(
                 return Ok(tcx.mk_layout(LayoutS::scalar(cx, data_ptr)));
             }
 
-            let unsized_part = tcx.struct_tail_erasing_lifetimes(pointee, param_env);
-
             let metadata = if let Some(metadata_def_id) = tcx.lang_items().metadata_type()
                 // Projection eagerly bails out when the pointee references errors,
                 // fall back to structurally deducing metadata.
                 && !pointee.references_error()
             {
-                let metadata_ty = tcx.normalize_erasing_regions(
+                let pointee_metadata = tcx.mk_projection(metadata_def_id, [pointee]);
+                let metadata_ty = match tcx.try_normalize_erasing_regions(
                     param_env,
-                    tcx.mk_projection(metadata_def_id, [pointee]),
-                );
+                    pointee_metadata,
+                ) {
+                    Ok(metadata_ty) => metadata_ty,
+                    Err(mut err) => {
+                        // Usually `<Ty as Pointee>::Metadata` can't be normalized because
+                        // its struct tail cannot be normalized either, so try to get a
+                        // more descriptive layout error here, which will lead to less confusing
+                        // diagnostics.
+                        match tcx.try_normalize_erasing_regions(
+                            param_env,
+                            tcx.struct_tail_without_normalization(pointee),
+                        ) {
+                            Ok(_) => {},
+                            Err(better_err) => {
+                                err = better_err;
+                            }
+                        }
+                        return Err(LayoutError::NormalizationFailure(pointee, err));
+                    },
+                };
+
                 let metadata_layout = cx.layout_of(metadata_ty)?;
                 // If the metadata is a 1-zst, then the pointer is thin.
                 if metadata_layout.is_zst() && metadata_layout.align.abi.bytes() == 1 {
@@ -163,10 +181,13 @@ fn layout_of_uncached<'tcx>(
                 }
 
                 let Abi::Scalar(metadata) = metadata_layout.abi else {
-                    return Err(LayoutError::Unknown(unsized_part));
+                    return Err(LayoutError::Unknown(pointee));
                 };
+
                 metadata
             } else {
+                let unsized_part = tcx.struct_tail_erasing_lifetimes(pointee, param_env);
+
                 match unsized_part.kind() {
                     ty::Foreign(..) => {
                         return Ok(tcx.mk_layout(LayoutS::scalar(cx, data_ptr)));
@@ -178,7 +199,7 @@ fn layout_of_uncached<'tcx>(
                         vtable
                     }
                     _ => {
-                        return Err(LayoutError::Unknown(unsized_part));
+                        return Err(LayoutError::Unknown(pointee));
                     }
                 }
             };