Migrate item_bounds to ty::Clause

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),

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,

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

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()),
@@ -71,23 +69,22 @@ 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));
         // Opaque types are implicitly sized unless a `?Sized` bound is found
         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)))
     })
 }

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(_) => {

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);
             }
             _ => {

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,
                         });

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}"

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;

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,

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();

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)
     }

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()
     }
 }
 

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)
                 }