Rollup merge of #112734 - dswij:bounds-predicates-clause, r=compiler-errors

Make `Bound::predicates`  use `Clause`

Part of #107250

`Bound::predicates` returns an iterator over `Binder<_, Clause>` instead of `Predicate`.

I tried updating `explicit_predicates_of` as well, but it seems that it needs a lot more change than I thought. Will do it in a separate PR instead.

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -31,9 +31,10 @@ use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::middle::stability::AllowUnstable;
 use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
+use rustc_middle::ty::DynKind;
 use rustc_middle::ty::GenericParamDefKind;
+use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::{self, Const, IsSuggestable, Ty, TyCtxt, TypeVisitableExt};
-use rustc_middle::ty::{DynKind, ToPredicate};
 use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
 use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::symbol::{kw, Ident, Symbol};
@@ -944,7 +945,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         let mut trait_bounds = vec![];
         let mut projection_bounds = vec![];
-        for (pred, span) in bounds.predicates() {
+        for (clause, span) in bounds.predicates() {
+            let pred: ty::Predicate<'tcx> = clause.to_predicate(tcx);
             let bound_pred = pred.kind();
             match bound_pred.skip_binder() {
                 ty::PredicateKind::Clause(clause) => match clause {

compiler/rustc_hir_analysis/src/bounds.rs

@@ -2,6 +2,7 @@
 //! `ty` form from the HIR.
 
 use rustc_hir::LangItem;
+use rustc_middle::ty::Binder;
 use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
 use rustc_span::Span;
 
@@ -23,52 +24,58 @@ use rustc_span::Span;
 /// include the self type (e.g., `trait_bounds`) but in others we do not
 #[derive(Default, PartialEq, Eq, Clone, Debug)]
 pub struct Bounds<'tcx> {
-    pub predicates: Vec<(ty::Predicate<'tcx>, Span)>,
+    pub predicates: Vec<(Binder<'tcx, ty::Clause<'tcx>>, Span)>,
 }
 
 impl<'tcx> Bounds<'tcx> {
     pub fn push_region_bound(
         &mut self,
-        tcx: TyCtxt<'tcx>,
+        _tcx: TyCtxt<'tcx>,
         region: ty::PolyTypeOutlivesPredicate<'tcx>,
         span: Span,
     ) {
-        self.predicates.push((region.to_predicate(tcx), span));
+        self.predicates.push((region.map_bound(|p| ty::Clause::TypeOutlives(p)), span));
     }
 
     pub fn push_trait_bound(
         &mut self,
-        tcx: TyCtxt<'tcx>,
+        _tcx: TyCtxt<'tcx>,
         trait_ref: ty::PolyTraitRef<'tcx>,
         span: Span,
         constness: ty::BoundConstness,
         polarity: ty::ImplPolarity,
     ) {
         self.predicates.push((
-            trait_ref
+            trait_ref.map_bound(|trait_ref| {
-                .map_bound(|trait_ref| ty::TraitPredicate { trait_ref, constness, polarity })
+                ty::Clause::Trait(ty::TraitPredicate { trait_ref, constness, polarity })
-                .to_predicate(tcx),
+            }),
             span,
         ));
     }
 
     pub fn push_projection_bound(
         &mut self,
-        tcx: TyCtxt<'tcx>,
+        _tcx: TyCtxt<'tcx>,
         projection: ty::PolyProjectionPredicate<'tcx>,
         span: Span,
     ) {
-        self.predicates.push((projection.to_predicate(tcx), span));
+        self.predicates.push((projection.map_bound(|proj| ty::Clause::Projection(proj)), span));
     }
 
     pub fn push_sized(&mut self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span) {
         let sized_def_id = tcx.require_lang_item(LangItem::Sized, Some(span));
         let trait_ref = ty::TraitRef::new(tcx, sized_def_id, [ty]);
         // Preferable to put this obligation first, since we report better errors for sized ambiguity.
-        self.predicates.insert(0, (trait_ref.without_const().to_predicate(tcx), span));
+        self.predicates.insert(
+            0,
+            (
+                ty::Binder::dummy(ty::Clause::Trait(trait_ref.without_const().to_predicate(tcx))),
+                span,
+            ),
+        );
     }
 
-    pub fn predicates(&self) -> impl Iterator<Item = (ty::Predicate<'tcx>, Span)> + '_ {
+    pub fn predicates(&self) -> impl Iterator<Item = (Binder<'tcx, ty::Clause<'tcx>>, Span)> + '_ {
         self.predicates.iter().cloned()
     }
 }

compiler/rustc_hir_analysis/src/collect/item_bounds.rs

@@ -3,6 +3,7 @@ use crate::astconv::{AstConv, OnlySelfBounds};
 use rustc_hir as hir;
 use rustc_infer::traits::util;
 use rustc_middle::ty::subst::InternalSubsts;
+use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::Span;
@@ -44,7 +45,12 @@ fn associated_type_bounds<'tcx>(
         }
     });
 
-    let all_bounds = tcx.arena.alloc_from_iter(bounds.predicates().chain(bounds_from_parent));
+    let all_bounds = tcx.arena.alloc_from_iter(
+        bounds
+            .predicates()
+            .map(|(clause, span)| (clause.to_predicate(tcx), span))
+            .chain(bounds_from_parent),
+    );
     debug!(
         "associated_type_bounds({}) = {:?}",
         tcx.def_path_str(assoc_item_def_id.to_def_id()),
@@ -72,7 +78,9 @@ 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.predicates())
+        tcx.arena.alloc_from_iter(
+            bounds.predicates().map(|(clause, span)| (clause.to_predicate(tcx), span)),
+        )
     })
 }
 

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -126,7 +126,8 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
         predicates.extend(
             icx.astconv()
                 .compute_bounds(tcx.types.self_param, self_bounds, OnlySelfBounds(false))
-                .predicates(),
+                .predicates()
+                .map(|(clause, span)| (clause.to_predicate(tcx), span)),
         );
     }
 
@@ -175,7 +176,9 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
                     param.span,
                 );
                 trace!(?bounds);
-                predicates.extend(bounds.predicates());
+                predicates.extend(
+                    bounds.predicates().map(|(clause, span)| (clause.to_predicate(tcx), span)),
+                );
                 trace!(?predicates);
             }
             GenericParamKind::Const { .. } => {
@@ -234,7 +237,9 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
                     bound_vars,
                     OnlySelfBounds(false),
                 );
-                predicates.extend(bounds.predicates());
+                predicates.extend(
+                    bounds.predicates().map(|(clause, span)| (clause.to_predicate(tcx), span)),
+                );
             }
 
             hir::WherePredicate::RegionPredicate(region_pred) => {
@@ -658,8 +663,12 @@ pub(super) fn implied_predicates_with_filter(
     };
 
     // Combine the two lists to form the complete set of superbounds:
-    let implied_bounds =
+    let implied_bounds = &*tcx.arena.alloc_from_iter(
-        &*tcx.arena.alloc_from_iter(superbounds.predicates().chain(where_bounds_that_match));
+        superbounds
+            .predicates()
+            .map(|(clause, span)| (clause.to_predicate(tcx), span))
+            .chain(where_bounds_that_match),
+    );
     debug!(?implied_bounds);
 
     // Now require that immediate supertraits are converted, which will, in
@@ -816,7 +825,7 @@ impl<'tcx> ItemCtxt<'tcx> {
             );
         }
 
-        bounds.predicates().collect()
+        bounds.predicates().map(|(clause, span)| (clause.to_predicate(self.tcx), span)).collect()
     }
 
     #[instrument(level = "trace", skip(self))]

compiler/rustc_middle/src/ty/mod.rs

@@ -1214,6 +1214,13 @@ impl<'tcx> ToPredicate<'tcx> for Clause<'tcx> {
     }
 }
 
+impl<'tcx> ToPredicate<'tcx> for Binder<'tcx, Clause<'tcx>> {
+    #[inline(always)]
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+        tcx.mk_predicate(self.map_bound(|clause| ty::PredicateKind::Clause(clause)))
+    }
+}
+
 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
     #[inline(always)]
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {

compiler/rustc_privacy/src/lib.rs

@@ -1270,13 +1270,13 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
             );
 
             for (pred, _) in bounds.predicates() {
-                match pred.kind().skip_binder() {
+                match pred.skip_binder() {
-                    ty::PredicateKind::Clause(ty::Clause::Trait(trait_predicate)) => {
+                    ty::Clause::Trait(trait_predicate) => {
                         if self.visit_trait(trait_predicate.trait_ref).is_break() {
                             return;
                         }
                     }
-                    ty::PredicateKind::Clause(ty::Clause::Projection(proj_predicate)) => {
+                    ty::Clause::Projection(proj_predicate) => {
                         let term = self.visit(proj_predicate.term);
                         if term.is_break()
                             || self.visit_projection_ty(proj_predicate.projection_ty).is_break()