Add bound_predicates_of and bound_explicit_predicates_of

jackh726 · jackh726 · commit e21624dc80a4 · 2022-08-02T22:44:08.000-04:00
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -16,9 +16,7 @@ use rustc_middle::mir::{
     FakeReadCause, LocalDecl, LocalInfo, LocalKind, Location, Operand, Place, PlaceRef,
     ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind, VarBindingForm,
 };
-use rustc_middle::ty::{
-    self, subst::Subst, suggest_constraining_type_params, EarlyBinder, PredicateKind, Ty,
-};
+use rustc_middle::ty::{self, subst::Subst, suggest_constraining_type_params, PredicateKind, Ty};
 use rustc_mir_dataflow::move_paths::{InitKind, MoveOutIndex, MovePathIndex};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
@@ -461,35 +459,37 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let tcx = self.infcx.tcx;
 
         // Find out if the predicates show that the type is a Fn or FnMut
-        let find_fn_kind_from_did = |predicates: &[(ty::Predicate<'tcx>, Span)], substs| {
-            predicates.iter().find_map(|(pred, _)| {
-                let pred = if let Some(substs) = substs {
-                    EarlyBinder(*pred).subst(tcx, substs).kind().skip_binder()
-                } else {
-                    pred.kind().skip_binder()
-                };
-                if let ty::PredicateKind::Trait(pred) = pred && pred.self_ty() == ty {
+        let find_fn_kind_from_did =
+            |predicates: ty::EarlyBinder<&[(ty::Predicate<'tcx>, Span)]>, substs| {
+                predicates.0.iter().find_map(|(pred, _)| {
+                    let pred = if let Some(substs) = substs {
+                        predicates.rebind(*pred).subst(tcx, substs).kind().skip_binder()
+                    } else {
+                        pred.kind().skip_binder()
+                    };
+                    if let ty::PredicateKind::Trait(pred) = pred && pred.self_ty() == ty {
                     if Some(pred.def_id()) == tcx.lang_items().fn_trait() {
                         return Some(hir::Mutability::Not);
                     } else if Some(pred.def_id()) == tcx.lang_items().fn_mut_trait() {
                         return Some(hir::Mutability::Mut);
                     }
                 }
-                None
-            })
-        };
+                    None
+                })
+            };
 
         // If the type is opaque/param/closure, and it is Fn or FnMut, let's suggest (mutably)
         // borrowing the type, since `&mut F: FnMut` iff `F: FnMut` and similarly for `Fn`.
         // These types seem reasonably opaque enough that they could be substituted with their
         // borrowed variants in a function body when we see a move error.
         let borrow_level = match ty.kind() {
             ty::Param(_) => find_fn_kind_from_did(
-                tcx.explicit_predicates_of(self.mir_def_id().to_def_id()).predicates,
+                tcx.bound_explicit_predicates_of(self.mir_def_id().to_def_id())
+                    .map_bound(|p| p.predicates),
                 None,
             ),
             ty::Opaque(did, substs) => {
-                find_fn_kind_from_did(tcx.explicit_item_bounds(*did), Some(*substs))
+                find_fn_kind_from_did(tcx.bound_explicit_item_bounds(*did), Some(*substs))
             }
             ty::Closure(_, substs) => match substs.as_closure().kind() {
                 ty::ClosureKind::Fn => Some(hir::Mutability::Not),
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
@@ -680,6 +680,20 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn bound_const_param_default(self, def_id: DefId) -> ty::EarlyBinder<ty::Const<'tcx>> {
         ty::EarlyBinder(self.const_param_default(def_id))
     }
+
+    pub fn bound_predicates_of(
+        self,
+        def_id: DefId,
+    ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> {
+        ty::EarlyBinder(self.predicates_of(def_id))
+    }
+
+    pub fn bound_explicit_predicates_of(
+        self,
+        def_id: DefId,
+    ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> {
+        ty::EarlyBinder(self.explicit_predicates_of(def_id))
+    }
 }
 
 struct OpaqueTypeExpander<'tcx> {
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -2356,11 +2356,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // obligation will normalize to `<$0 as Iterator>::Item = $1` and
         // `$1: Copy`, so we must ensure the obligations are emitted in
         // that order.
-        let predicates = tcx.predicates_of(def_id);
+        let predicates = tcx.bound_predicates_of(def_id);
         debug!(?predicates);
-        assert_eq!(predicates.parent, None);
-        let mut obligations = Vec::with_capacity(predicates.predicates.len());
-        for (predicate, span) in predicates.predicates {
+        assert_eq!(predicates.0.parent, None);
+        let mut obligations = Vec::with_capacity(predicates.0.predicates.len());
+        for (predicate, span) in predicates.0.predicates {
             let span = *span;
             let cause = cause.clone().derived_cause(parent_trait_pred, |derived| {
                 ImplDerivedObligation(Box::new(ImplDerivedObligationCause {
@@ -2374,7 +2374,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 param_env,
                 cause.clone(),
                 recursion_depth,
-                EarlyBinder(*predicate).subst(tcx, substs),
+                predicates.rebind(*predicate).subst(tcx, substs),
                 &mut obligations,
             );
             obligations.push(Obligation { cause, recursion_depth, param_env, predicate });
diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
@@ -51,11 +51,11 @@ impl<'tcx> RustIrDatabase<'tcx> {
     where
         ty::Predicate<'tcx>: LowerInto<'tcx, std::option::Option<T>>,
     {
-        self.interner
-            .tcx
-            .explicit_item_bounds(def_id)
+        let bounds = self.interner.tcx.bound_explicit_item_bounds(def_id);
+        bounds
+            .0
             .iter()
-            .map(|(bound, _)| EarlyBinder(*bound).subst(self.interner.tcx, &bound_vars))
+            .map(|(bound, _)| bounds.rebind(*bound).subst(self.interner.tcx, &bound_vars))
             .filter_map(|bound| LowerInto::<Option<_>>::lower_into(bound, self.interner))
             .collect()
     }
@@ -268,21 +268,20 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
 
         let where_clauses = self.where_clauses_for(def_id, bound_vars);
 
-        let sig = self.interner.tcx.fn_sig(def_id);
+        let sig = self.interner.tcx.bound_fn_sig(def_id);
         let (inputs_and_output, iobinders, _) = crate::chalk::lowering::collect_bound_vars(
             self.interner,
             self.interner.tcx,
-            EarlyBinder(sig.inputs_and_output()).subst(self.interner.tcx, bound_vars),
+            sig.map_bound(|s| s.inputs_and_output()).subst(self.interner.tcx, bound_vars),
         );
 
         let argument_types = inputs_and_output[..inputs_and_output.len() - 1]
             .iter()
-            .map(|t| {
-                EarlyBinder(*t).subst(self.interner.tcx, &bound_vars).lower_into(self.interner)
-            })
+            .map(|t| sig.rebind(*t).subst(self.interner.tcx, &bound_vars).lower_into(self.interner))
             .collect();
 
-        let return_type = EarlyBinder(inputs_and_output[inputs_and_output.len() - 1])
+        let return_type = sig
+            .rebind(inputs_and_output[inputs_and_output.len() - 1])
             .subst(self.interner.tcx, &bound_vars)
             .lower_into(self.interner);
 
@@ -295,7 +294,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         };
         Arc::new(chalk_solve::rust_ir::FnDefDatum {
             id: fn_def_id,
-            sig: sig.lower_into(self.interner),
+            sig: sig.0.lower_into(self.interner),
             binders: chalk_ir::Binders::new(binders, bound),
         })
     }
@@ -503,12 +502,14 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
 
         let identity_substs = InternalSubsts::identity_for_item(self.interner.tcx, opaque_ty_id.0);
 
+        let explicit_item_bounds = self.interner.tcx.bound_explicit_item_bounds(opaque_ty_id.0);
         let bounds =
-            self.interner
-                .tcx
-                .explicit_item_bounds(opaque_ty_id.0)
+            explicit_item_bounds
+                .0
                 .iter()
-                .map(|(bound, _)| EarlyBinder(*bound).subst(self.interner.tcx, &bound_vars))
+                .map(|(bound, _)| {
+                    explicit_item_bounds.rebind(*bound).subst(self.interner.tcx, &bound_vars)
+                })
                 .map(|bound| {
                     bound.fold_with(&mut ReplaceOpaqueTyFolder {
                         tcx: self.interner.tcx,
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -15,8 +15,8 @@ use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst};
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{
-    self, AdtKind, DefIdTree, EarlyBinder, GenericParamDefKind, ToPredicate, Ty, TyCtxt,
-    TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor,
+    self, AdtKind, DefIdTree, GenericParamDefKind, ToPredicate, Ty, TyCtxt, TypeFoldable,
+    TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::{sym, Ident, Symbol};
@@ -1295,7 +1295,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
     let infcx = wfcx.infcx;
     let tcx = wfcx.tcx();
 
-    let predicates = tcx.predicates_of(def_id);
+    let predicates = tcx.bound_predicates_of(def_id.to_def_id());
     let generics = tcx.generics_of(def_id);
 
     let is_our_default = |def: &ty::GenericParamDef| match def.kind {
@@ -1392,6 +1392,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
 
     // Now we build the substituted predicates.
     let default_obligations = predicates
+        .0
         .predicates
         .iter()
         .flat_map(|&(pred, sp)| {
@@ -1422,15 +1423,15 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             }
             let mut param_count = CountParams::default();
             let has_region = pred.visit_with(&mut param_count).is_break();
-            let substituted_pred = EarlyBinder(pred).subst(tcx, substs);
+            let substituted_pred = predicates.rebind(pred).subst(tcx, substs);
             // Don't check non-defaulted params, dependent defaults (including lifetimes)
             // or preds with multiple params.
             if substituted_pred.has_param_types_or_consts()
                 || param_count.params.len() > 1
                 || has_region
             {
                 None
-            } else if predicates.predicates.iter().any(|&(p, _)| p == substituted_pred) {
+            } else if predicates.0.predicates.iter().any(|&(p, _)| p == substituted_pred) {
                 // Avoid duplication of predicates that contain no parameters, for example.
                 None
             } else {
@@ -1456,7 +1457,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             traits::Obligation::new(cause, wfcx.param_env, pred)
         });
 
-    let predicates = predicates.instantiate_identity(tcx);
+    let predicates = predicates.0.instantiate_identity(tcx);
 
     let predicates = wfcx.normalize(span, None, predicates);
 
