Stop calling impl_polarity when impl_trait_ref was also called

Author: oli-obk

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1671,9 +1671,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         .is_accessible_from(self.item_def_id(), tcx)
                     && tcx.all_impls(*trait_def_id)
                         .any(|impl_def_id| {
-                            let trait_ref = tcx.impl_trait_ref(impl_def_id);
-                            trait_ref.is_some_and(|trait_ref| {
-                                let impl_ = trait_ref.instantiate(
+                            let impl_header = tcx.impl_trait_header(impl_def_id);
+                            impl_header.is_some_and(|header| {
+                                let header = header.instantiate(
                                     tcx,
                                     infcx.fresh_args_for_item(DUMMY_SP, impl_def_id),
                                 );
@@ -1685,11 +1685,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 infcx
                                     .can_eq(
                                         ty::ParamEnv::empty(),
-                                        impl_.self_ty(),
+                                        header.trait_ref.self_ty(),
                                         value,
-                                    )
+                                    ) && header.polarity != ty::ImplPolarity::Negative
                             })
-                            && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
                         })
             })
             .map(|trait_def_id| tcx.def_path_str(trait_def_id))
@@ -1735,13 +1734,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             } else {
                 // Find all the types that have an `impl` for the trait.
                 tcx.all_impls(trait_def_id)
-                    .filter(|impl_def_id| {
+                    .filter_map(|impl_def_id| tcx.impl_trait_header(impl_def_id))
+                    .filter(|header| {
                         // Consider only accessible traits
                         tcx.visibility(trait_def_id).is_accessible_from(self.item_def_id(), tcx)
-                            && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
+                            && header.skip_binder().polarity != ty::ImplPolarity::Negative
                     })
-                    .filter_map(|impl_def_id| tcx.impl_trait_ref(impl_def_id))
-                    .map(|impl_| impl_.instantiate_identity().self_ty())
+                    .map(|header| header.instantiate_identity().trait_ref.self_ty())
                     // We don't care about blanket impls.
                     .filter(|self_ty| !self_ty.has_non_region_param())
                     .map(|self_ty| tcx.erase_regions(self_ty).to_string())

compiler/rustc_hir_analysis/src/check/check.rs

@@ -474,8 +474,12 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) {
         }
         DefKind::Fn => {} // entirely within check_item_body
         DefKind::Impl { of_trait } => {
-            if of_trait && let Some(impl_trait_ref) = tcx.impl_trait_ref(def_id) {
-                check_impl_items_against_trait(tcx, def_id, impl_trait_ref.instantiate_identity());
+            if of_trait && let Some(impl_trait_header) = tcx.impl_trait_header(def_id) {
+                check_impl_items_against_trait(
+                    tcx,
+                    def_id,
+                    impl_trait_header.instantiate_identity(),
+                );
                 check_on_unimplemented(tcx, def_id);
             }
         }
@@ -666,19 +670,19 @@ pub(super) fn check_specialization_validity<'tcx>(
 fn check_impl_items_against_trait<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_id: LocalDefId,
-    impl_trait_ref: ty::TraitRef<'tcx>,
+    impl_trait_header: ty::ImplTraitHeader<'tcx>,
 ) {
     // If the trait reference itself is erroneous (so the compilation is going
     // to fail), skip checking the items here -- the `impl_item` table in `tcx`
     // isn't populated for such impls.
-    if impl_trait_ref.references_error() {
+    if impl_trait_header.references_error() {
         return;
     }
 
     let impl_item_refs = tcx.associated_item_def_ids(impl_id);
 
     // Negative impls are not expected to have any items
-    match tcx.impl_polarity(impl_id) {
+    match impl_trait_header.polarity {
         ty::ImplPolarity::Reservation | ty::ImplPolarity::Positive => {}
         ty::ImplPolarity::Negative => {
             if let [first_item_ref, ..] = impl_item_refs {
@@ -695,7 +699,7 @@ fn check_impl_items_against_trait<'tcx>(
         }
     }
 
-    let trait_def = tcx.trait_def(impl_trait_ref.def_id);
+    let trait_def = tcx.trait_def(impl_trait_header.trait_ref.def_id);
 
     for &impl_item in impl_item_refs {
         let ty_impl_item = tcx.associated_item(impl_item);
@@ -714,10 +718,10 @@ fn check_impl_items_against_trait<'tcx>(
                 ));
             }
             ty::AssocKind::Fn => {
-                compare_impl_method(tcx, ty_impl_item, ty_trait_item, impl_trait_ref);
+                compare_impl_method(tcx, ty_impl_item, ty_trait_item, impl_trait_header.trait_ref);
             }
             ty::AssocKind::Type => {
-                compare_impl_ty(tcx, ty_impl_item, ty_trait_item, impl_trait_ref);
+                compare_impl_ty(tcx, ty_impl_item, ty_trait_item, impl_trait_header.trait_ref);
             }
         }
 
@@ -737,7 +741,7 @@ fn check_impl_items_against_trait<'tcx>(
         let mut must_implement_one_of: Option<&[Ident]> =
             trait_def.must_implement_one_of.as_deref();
 
-        for &trait_item_id in tcx.associated_item_def_ids(impl_trait_ref.def_id) {
+        for &trait_item_id in tcx.associated_item_def_ids(impl_trait_header.trait_ref.def_id) {
             let leaf_def = ancestors.leaf_def(tcx, trait_item_id);
 
             let is_implemented = leaf_def
@@ -815,7 +819,7 @@ fn check_impl_items_against_trait<'tcx>(
 
         if let Some(missing_items) = must_implement_one_of {
             let attr_span = tcx
-                .get_attr(impl_trait_ref.def_id, sym::rustc_must_implement_one_of)
+                .get_attr(impl_trait_header.trait_ref.def_id, sym::rustc_must_implement_one_of)
                 .map(|attr| attr.span);
 
             missing_items_must_implement_one_of_err(

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -245,9 +245,9 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
         // won't be allowed unless there's an *explicit* implementation of `Send`
         // for `T`
         hir::ItemKind::Impl(impl_) => {
-            let is_auto = tcx
-                .impl_trait_ref(def_id)
-                .is_some_and(|trait_ref| tcx.trait_is_auto(trait_ref.skip_binder().def_id));
+            let header = tcx.impl_trait_header(def_id);
+            let is_auto = header
+                .is_some_and(|header| tcx.trait_is_auto(header.skip_binder().trait_ref.def_id));
             let mut res = Ok(());
             if let (hir::Defaultness::Default { .. }, true) = (impl_.defaultness, is_auto) {
                 let sp = impl_.of_trait.as_ref().map_or(item.span, |t| t.path.span);
@@ -259,11 +259,12 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
                     .emit());
             }
             // We match on both `ty::ImplPolarity` and `ast::ImplPolarity` just to get the `!` span.
-            match tcx.impl_polarity(def_id) {
-                ty::ImplPolarity::Positive => {
+            match header.map(|h| h.skip_binder().polarity) {
+                // `None` means this is an inherent impl
+                Some(ty::ImplPolarity::Positive) | None => {
                     res = res.and(check_impl(tcx, item, impl_.self_ty, &impl_.of_trait));
                 }
-                ty::ImplPolarity::Negative => {
+                Some(ty::ImplPolarity::Negative) => {
                     let ast::ImplPolarity::Negative(span) = impl_.polarity else {
                         bug!("impl_polarity query disagrees with impl's polarity in AST");
                     };
@@ -280,7 +281,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
                         .emit());
                     }
                 }
-                ty::ImplPolarity::Reservation => {
+                Some(ty::ImplPolarity::Reservation) => {
                     // FIXME: what amount of WF checking do we need for reservation impls?
                 }
             }

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -3134,12 +3134,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     if self
                         .tcx
                         .all_impls(candidate.def_id)
-                        .filter(|imp_did| {
-                            self.tcx.impl_polarity(*imp_did) == ty::ImplPolarity::Negative
+                        .map(|imp_did| {
+                            self.tcx.impl_trait_header(imp_did).expect(
+                                "inherent impls can't be candidates, only trait impls can be",
+                            )
+                        })
+                        .filter(|header| {
+                            header.skip_binder().polarity == ty::ImplPolarity::Negative
                         })
-                        .any(|imp_did| {
-                            let imp =
-                                self.tcx.impl_trait_ref(imp_did).unwrap().instantiate_identity();
+                        .any(|header| {
+                            let imp = header.instantiate_identity().trait_ref;
                             let imp_simp =
                                 simplify_type(self.tcx, imp.self_ty(), TreatParams::ForLookup);
                             imp_simp.is_some_and(|s| s == simp_rcvr_ty)

compiler/rustc_middle/src/ty/mod.rs

@@ -1590,15 +1590,16 @@ impl<'tcx> TyCtxt<'tcx> {
         def_id1: DefId,
         def_id2: DefId,
     ) -> Option<ImplOverlapKind> {
-        let impl_trait_ref1 = self.impl_trait_ref(def_id1).unwrap().instantiate_identity();
-        let impl_trait_ref2 = self.impl_trait_ref(def_id2).unwrap().instantiate_identity();
+        let impl1 = self.impl_trait_header(def_id1).unwrap().instantiate_identity();
+        let impl2 = self.impl_trait_header(def_id2).unwrap().instantiate_identity();
+
         // If either trait impl references an error, they're allowed to overlap,
         // as one of them essentially doesn't exist.
-        if impl_trait_ref1.references_error() || impl_trait_ref2.references_error() {
+        if impl1.references_error() || impl2.references_error() {
             return Some(ImplOverlapKind::Permitted { marker: false });
         }
 
-        match (self.impl_polarity(def_id1), self.impl_polarity(def_id2)) {
+        match (impl1.polarity, impl2.polarity) {
             (ImplPolarity::Reservation, _) | (_, ImplPolarity::Reservation) => {
                 // `#[rustc_reservation_impl]` impls don't overlap with anything
                 return Some(ImplOverlapKind::Permitted { marker: false });
@@ -1615,7 +1616,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let is_marker_overlap = {
             let is_marker_impl =
                 |trait_ref: TraitRef<'_>| -> bool { self.trait_def(trait_ref.def_id).is_marker };
-            is_marker_impl(impl_trait_ref1) && is_marker_impl(impl_trait_ref2)
+            is_marker_impl(impl1.trait_ref) && is_marker_impl(impl2.trait_ref)
         };
 
         if is_marker_overlap {

compiler/rustc_monomorphize/src/collector.rs

@@ -1347,18 +1347,17 @@ fn create_mono_items_for_default_impls<'tcx>(
     item: hir::ItemId,
     output: &mut MonoItems<'tcx>,
 ) {
-    let polarity = tcx.impl_polarity(item.owner_id);
-    if matches!(polarity, ty::ImplPolarity::Negative) {
+    let Some(impl_) = tcx.impl_trait_header(item.owner_id) else {
         return;
-    }
+    };
 
-    if tcx.generics_of(item.owner_id).own_requires_monomorphization() {
+    if matches!(impl_.skip_binder().polarity, ty::ImplPolarity::Negative) {
         return;
     }
 
-    let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) else {
+    if tcx.generics_of(item.owner_id).own_requires_monomorphization() {
         return;
-    };
+    }
 
     // Lifetimes never affect trait selection, so we are allowed to eagerly
     // instantiate an instance of an impl method if the impl (and method,
@@ -1376,7 +1375,7 @@ fn create_mono_items_for_default_impls<'tcx>(
         }
     };
     let impl_args = GenericArgs::for_item(tcx, item.owner_id.to_def_id(), only_region_params);
-    let trait_ref = trait_ref.instantiate(tcx, impl_args);
+    let trait_ref = impl_.instantiate(tcx, impl_args).trait_ref;
 
     // Unlike 'lazy' monomorphization that begins by collecting items transitively
     // called by `main` or other global items, when eagerly monomorphizing impl

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -39,15 +39,18 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
     ) -> Result<Candidate<'tcx>, NoSolution> {
         let tcx = ecx.tcx();
 
-        let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
+        let impl_trait_header = tcx.impl_trait_header(impl_def_id).unwrap();
         let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::ForLookup };
-        if !drcx.args_may_unify(goal.predicate.trait_ref.args, impl_trait_ref.skip_binder().args) {
+        if !drcx.args_may_unify(
+            goal.predicate.trait_ref.args,
+            impl_trait_header.skip_binder().trait_ref.args,
+        ) {
             return Err(NoSolution);
         }
 
-        let impl_polarity = tcx.impl_polarity(impl_def_id);
         // An upper bound of the certainty of this goal, used to lower the certainty
         // of reservation impl to ambiguous during coherence.
+        let impl_polarity = impl_trait_header.skip_binder().polarity;
         let maximal_certainty = match impl_polarity {
             ty::ImplPolarity::Positive | ty::ImplPolarity::Negative => {
                 match impl_polarity == goal.predicate.polarity {
@@ -63,7 +66,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
 
         ecx.probe_trait_candidate(CandidateSource::Impl(impl_def_id)).enter(|ecx| {
             let impl_args = ecx.fresh_args_for_item(impl_def_id);
-            let impl_trait_ref = impl_trait_ref.instantiate(tcx, impl_args);
+            let impl_trait_ref = impl_trait_header.instantiate(tcx, impl_args).trait_ref;
 
             ecx.eq(goal.param_env, goal.predicate.trait_ref, impl_trait_ref)?;
             let where_clause_bounds = tcx

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -1980,13 +1980,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             .tcx
             .all_impls(trait_pred.def_id())
             .filter_map(|def_id| {
-                if self.tcx.impl_polarity(def_id) == ty::ImplPolarity::Negative
+                let imp = self.tcx.impl_trait_header(def_id).unwrap().skip_binder();
+                if imp.polarity == ty::ImplPolarity::Negative
                     || !self.tcx.is_user_visible_dep(def_id.krate)
                 {
                     return None;
                 }
-
-                let imp = self.tcx.impl_trait_ref(def_id).unwrap().skip_binder();
+                let imp = imp.trait_ref;
 
                 self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false).map(
                     |similarity| ImplCandidate { trait_ref: imp, similarity, impl_def_id: def_id },
@@ -2165,12 +2165,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 .tcx
                 .all_impls(def_id)
                 // Ignore automatically derived impls and `!Trait` impls.
-                .filter(|&def_id| {
-                    self.tcx.impl_polarity(def_id) != ty::ImplPolarity::Negative
+                .filter_map(|def_id| self.tcx.impl_trait_header(def_id))
+                .map(ty::EarlyBinder::instantiate_identity)
+                .filter(|header| {
+                    header.polarity != ty::ImplPolarity::Negative
                         || self.tcx.is_automatically_derived(def_id)
                 })
-                .filter_map(|def_id| self.tcx.impl_trait_ref(def_id))
-                .map(ty::EarlyBinder::instantiate_identity)
+                .map(|header| header.trait_ref)
                 .filter(|trait_ref| {
                     let self_ty = trait_ref.self_ty();
                     // Avoid mentioning type parameters.

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

@@ -560,20 +560,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // Before we create the substitutions and everything, first
                 // consider a "quick reject". This avoids creating more types
                 // and so forth that we need to.
-                let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
-                if !drcx.args_may_unify(obligation_args, impl_trait_ref.skip_binder().args) {
+                let impl_trait_header = self.tcx().impl_trait_header(impl_def_id).unwrap();
+                if !drcx
+                    .args_may_unify(obligation_args, impl_trait_header.skip_binder().trait_ref.args)
+                {
                     return;
                 }
                 if self.reject_fn_ptr_impls(
                     impl_def_id,
                     obligation,
-                    impl_trait_ref.skip_binder().self_ty(),
+                    impl_trait_header.skip_binder().trait_ref.self_ty(),
                 ) {
                     return;
                 }
 
                 self.infcx.probe(|_| {
-                    if let Ok(_args) = self.match_impl(impl_def_id, impl_trait_ref, obligation) {
+                    if let Ok(_args) = self.match_impl(impl_def_id, impl_trait_header, obligation) {
                         candidates.vec.push(ImplCandidate(impl_def_id));
                     }
                 });

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

@@ -2404,8 +2404,8 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
         impl_def_id: DefId,
         obligation: &PolyTraitObligation<'tcx>,
     ) -> Normalized<'tcx, GenericArgsRef<'tcx>> {
-        let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
-        match self.match_impl(impl_def_id, impl_trait_ref, obligation) {
+        let impl_trait_header = self.tcx().impl_trait_header(impl_def_id).unwrap();
+        match self.match_impl(impl_def_id, impl_trait_header, obligation) {
             Ok(args) => args,
             Err(()) => {
                 // FIXME: A rematch may fail when a candidate cache hit occurs
@@ -2438,7 +2438,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
     fn match_impl(
         &mut self,
         impl_def_id: DefId,
-        impl_trait_ref: EarlyBinder<ty::TraitRef<'tcx>>,
+        impl_trait_header: EarlyBinder<ty::ImplTraitHeader<'tcx>>,
         obligation: &PolyTraitObligation<'tcx>,
     ) -> Result<Normalized<'tcx, GenericArgsRef<'tcx>>, ()> {
         let placeholder_obligation =
@@ -2447,12 +2447,12 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
 
         let impl_args = self.infcx.fresh_args_for_item(obligation.cause.span, impl_def_id);
 
-        let impl_trait_ref = impl_trait_ref.instantiate(self.tcx(), impl_args);
-        if impl_trait_ref.references_error() {
+        let impl_trait_header = impl_trait_header.instantiate(self.tcx(), impl_args);
+        if impl_trait_header.references_error() {
             return Err(());
         }
 
-        debug!(?impl_trait_ref);
+        debug!(?impl_trait_header);
 
         let Normalized { value: impl_trait_ref, obligations: mut nested_obligations } =
             ensure_sufficient_stack(|| {
@@ -2461,7 +2461,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                     obligation.param_env,
                     obligation.cause.clone(),
                     obligation.recursion_depth + 1,
-                    impl_trait_ref,
+                    impl_trait_header.trait_ref,
                 )
             });
 
@@ -2482,9 +2482,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
             })?;
         nested_obligations.extend(obligations);
 
-        if !self.is_intercrate()
-            && self.tcx().impl_polarity(impl_def_id) == ty::ImplPolarity::Reservation
-        {
+        if !self.is_intercrate() && impl_trait_header.polarity == ty::ImplPolarity::Reservation {
             debug!("reservation impls only apply in intercrate mode");
             return Err(());
         }