Add new ToPredicate impls and TraitRef methods to remove some ty::Binber::dummy calls

Author: WaffleLapkin

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -157,13 +157,8 @@ impl Qualif for NeedsNonConstDrop {
             cx.tcx,
             ObligationCause::dummy_with_span(cx.body.span),
             cx.param_env,
-            ty::Binder::dummy(ty::TraitRef::from_lang_item(
-                cx.tcx,
-                LangItem::Destruct,
-                cx.body.span,
-                [ty],
-            ))
-            .with_constness(ty::BoundConstness::ConstIfConst),
+            ty::TraitRef::from_lang_item(cx.tcx, LangItem::Destruct, cx.body.span, [ty])
+                .with_constness(ty::BoundConstness::ConstIfConst),
         );
 
         let infcx = cx.tcx.infer_ctxt().build();

compiler/rustc_hir_analysis/src/bounds.rs

@@ -57,7 +57,7 @@ impl<'tcx> Bounds<'tcx> {
 
     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::Binder::dummy(ty::TraitRef::new(tcx, sized_def_id, [ty]));
+        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));
     }

compiler/rustc_middle/src/ty/mod.rs

@@ -1207,6 +1207,18 @@ impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for Binder<'tcx, TraitRef
     }
 }
 
+impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for TraitRef<'tcx> {
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
+        ty::Binder::dummy(self).to_predicate(tcx)
+    }
+}
+
+impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for TraitPredicate<'tcx> {
+    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
+        ty::Binder::dummy(self)
+    }
+}
+
 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(|p| PredicateKind::Clause(Clause::Trait(p))).to_predicate(tcx)
@@ -1231,6 +1243,12 @@ impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
     }
 }
 
+impl<'tcx> ToPredicate<'tcx> for TraitPredicate<'tcx> {
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+        PredicateKind::Clause(Clause::Trait(self)).to_predicate(tcx)
+    }
+}
+
 impl<'tcx> Predicate<'tcx> {
     pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
         let predicate = self.kind();

compiler/rustc_middle/src/ty/sty.rs

@@ -871,6 +871,18 @@ impl<'tcx> TraitRef<'tcx> {
         )
     }
 
+    /// Converts this trait ref to a trait predicate with a given `constness` and a positive polarity.
+    #[inline]
+    pub fn with_constness(self, constness: ty::BoundConstness) -> ty::TraitPredicate<'tcx> {
+        ty::TraitPredicate { trait_ref: self, constness, polarity: ty::ImplPolarity::Positive }
+    }
+
+    /// Converts this trait ref to a trait predicate without `const` and a positive polarity.
+    #[inline]
+    pub fn without_const(self) -> ty::TraitPredicate<'tcx> {
+        self.with_constness(ty::BoundConstness::NotConst)
+    }
+
     #[inline]
     pub fn self_ty(&self) -> Ty<'tcx> {
         self.substs.type_at(0)

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -127,7 +127,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
     ty: Ty<'tcx>,
     def_id: DefId,
 ) -> bool {
-    let trait_ref = ty::Binder::dummy(ty::TraitRef::new(infcx.tcx, def_id, [ty]));
+    let trait_ref = ty::TraitRef::new(infcx.tcx, def_id, [ty]);
     pred_known_to_hold_modulo_regions(infcx, param_env, trait_ref.without_const())
 }
 

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -769,13 +769,10 @@ fn receiver_is_dispatchable<'tcx>(
         let param_env = tcx.param_env(method.def_id);
 
         // Self: Unsize<U>
-        let unsize_predicate = ty::Binder::dummy(ty::TraitRef::new(
-            tcx,
-            unsize_did,
-            [tcx.types.self_param, unsized_self_ty],
-        ))
-        .without_const()
-        .to_predicate(tcx);
+        let unsize_predicate =
+            ty::TraitRef::new(tcx, unsize_did, [tcx.types.self_param, unsized_self_ty])
+                .without_const()
+                .to_predicate(tcx);
 
         // U: Trait<Arg1, ..., ArgN>
         let trait_predicate = {

compiler/rustc_trait_selection/src/traits/project.rs

@@ -1319,7 +1319,7 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
         let trait_substs =
             obligation.predicate.substs.truncate_to(tcx, tcx.generics_of(trait_def_id));
         // FIXME(named-returns): Binders
-        let trait_predicate = ty::Binder::dummy(ty::TraitRef::new(tcx, trait_def_id, trait_substs));
+        let trait_predicate = ty::TraitRef::new(tcx, trait_def_id, trait_substs);
 
         let _ = selcx.infcx.commit_if_ok(|_| {
             match selcx.select(&obligation.with(tcx, trait_predicate)) {
@@ -1682,10 +1682,8 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
                             if selcx.infcx.predicate_must_hold_modulo_regions(
                                 &obligation.with(
                                     selcx.tcx(),
-                                    ty::Binder::dummy(
-                                        ty::TraitRef::from_lang_item(selcx.tcx(), LangItem::Sized, obligation.cause.span(),[self_ty]),
-                                    )
-                                    .without_const(),
+                                    ty::TraitRef::from_lang_item(selcx.tcx(), LangItem::Sized, obligation.cause.span(),[self_ty])
+                                        .without_const(),
                                 ),
                             ) =>
                         {
@@ -1948,12 +1946,12 @@ fn confirm_builtin_candidate<'cx, 'tcx>(
             )
         });
         if check_is_sized {
-            let sized_predicate = ty::Binder::dummy(ty::TraitRef::from_lang_item(
+            let sized_predicate = ty::TraitRef::from_lang_item(
                 tcx,
                 LangItem::Sized,
                 obligation.cause.span(),
                 [self_ty],
-            ))
+            )
             .without_const();
             obligations.push(obligation.with(tcx, sized_predicate));
         }

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -1049,12 +1049,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
 
                 // We can only make objects from sized types.
-                let tr = ty::Binder::dummy(ty::TraitRef::from_lang_item(
-                    tcx,
-                    LangItem::Sized,
-                    cause.span,
-                    [source],
-                ));
+                let tr = ty::TraitRef::from_lang_item(tcx, LangItem::Sized, cause.span, [source]);
                 nested.push(predicate_to_obligation(tr.without_const().to_predicate(tcx)));
 
                 // If the type is `Foo + 'a`, ensure that the type

compiler/rustc_ty_utils/src/ty.rs

@@ -62,9 +62,8 @@ fn sized_constraint_for_ty<'tcx>(
             // it on the impl.
 
             let Some(sized_trait) = tcx.lang_items().sized_trait() else { return vec![ty] };
-            let sized_predicate = ty::Binder::dummy(ty::TraitRef::new(tcx, sized_trait, [ty]))
-                .without_const()
-                .to_predicate(tcx);
+            let sized_predicate =
+                ty::TraitRef::new(tcx, sized_trait, [ty]).without_const().to_predicate(tcx);
             let predicates = tcx.predicates_of(adtdef.did()).predicates;
             if predicates.iter().any(|(p, _)| *p == sized_predicate) { vec![] } else { vec![ty] }
         }