Fetch less HIR in signature check.

compiler/rustc_hir_analysis/src/check/check.rs

@@ -530,46 +530,33 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
         }
         DefKind::Fn => {} // entirely within check_item_body
         DefKind::Impl { of_trait } => {
-            if of_trait {
+            if of_trait && let Some(impl_trait_ref) = tcx.impl_trait_ref(id.owner_id) {
-                let it = tcx.hir().item(id);
+                check_impl_items_against_trait(
-                let hir::ItemKind::Impl(impl_) = it.kind else { return };
+                    tcx,
-                debug!("ItemKind::Impl {} with id {:?}", it.ident, it.owner_id);
+                    id.owner_id.def_id,
-                if let Some(impl_trait_ref) = tcx.impl_trait_ref(it.owner_id) {
+                    impl_trait_ref.subst_identity(),
-                    check_impl_items_against_trait(
+                );
-                        tcx,
+                check_on_unimplemented(tcx, id);
-                        it.span,
-                        it.owner_id.def_id,
-                        impl_trait_ref.subst_identity(),
-                        &impl_.items,
-                    );
-                    check_on_unimplemented(tcx, it);
-                }
             }
         }
         DefKind::Trait => {
-            let it = tcx.hir().item(id);
+            let assoc_items = tcx.associated_items(id.owner_id);
-            let hir::ItemKind::Trait(_, _, _, _, items) = it.kind else {
+            check_on_unimplemented(tcx, id);
-                return;
-            };
-            check_on_unimplemented(tcx, it);
 
-            for item in items.iter() {
+            for assoc_item in assoc_items.in_definition_order() {
-                let item = tcx.hir().trait_item(item.id);
+                match assoc_item.kind {
-                match &item.kind {
+                    ty::AssocKind::Fn => {
-                    hir::TraitItemKind::Fn(sig, _) => {
+                        let abi = tcx.fn_sig(assoc_item.def_id).skip_binder().abi();
-                        let abi = sig.header.abi;
+                        fn_maybe_err(tcx, assoc_item.ident(tcx).span, abi);
-                        fn_maybe_err(tcx, item.ident.span, abi);
                     }
-                    hir::TraitItemKind::Type(.., Some(default)) => {
+                    ty::AssocKind::Type if assoc_item.defaultness(tcx).has_value() => {
-                        let assoc_item = tcx.associated_item(item.owner_id);
                         let trait_substs =
-                            InternalSubsts::identity_for_item(tcx, it.owner_id.to_def_id());
+                            InternalSubsts::identity_for_item(tcx, id.owner_id.to_def_id());
                         let _: Result<_, rustc_errors::ErrorGuaranteed> = check_type_bounds(
                             tcx,
                             assoc_item,
                             assoc_item,
-                            default.span,
+                            tcx.mk_trait_ref(id.owner_id.to_def_id(), trait_substs),
-                            tcx.mk_trait_ref(it.owner_id.to_def_id(), trait_substs),
                         );
                     }
                     _ => {}
@@ -681,7 +668,7 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
     }
 }
 
-pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, item: &hir::Item<'_>) {
+pub(super) fn check_on_unimplemented(tcx: TyCtxt<'_>, item: hir::ItemId) {
     // an error would be reported if this fails.
     let _ = OnUnimplementedDirective::of_item(tcx, item.owner_id.to_def_id());
 }
@@ -691,7 +678,7 @@ pub(super) fn check_specialization_validity<'tcx>(
     trait_def: &ty::TraitDef,
     trait_item: &ty::AssocItem,
     impl_id: DefId,
-    impl_item: &hir::ImplItemRef,
+    impl_item: DefId,
 ) {
     let Ok(ancestors) = trait_def.ancestors(tcx, impl_id) else { return };
     let mut ancestor_impls = ancestors.skip(1).filter_map(|parent| {
@@ -737,10 +724,8 @@ pub(super) fn check_specialization_validity<'tcx>(
 
 fn check_impl_items_against_trait<'tcx>(
     tcx: TyCtxt<'tcx>,
-    full_impl_span: Span,
     impl_id: LocalDefId,
     impl_trait_ref: ty::TraitRef<'tcx>,
-    impl_item_refs: &[hir::ImplItemRef],
 ) {
     // 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`
@@ -749,12 +734,14 @@ fn check_impl_items_against_trait<'tcx>(
         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) {
         ty::ImplPolarity::Reservation | ty::ImplPolarity::Positive => {}
         ty::ImplPolarity::Negative => {
             if let [first_item_ref, ..] = impl_item_refs {
-                let first_item_span = tcx.hir().impl_item(first_item_ref.id).span;
+                let first_item_span = tcx.def_span(first_item_ref);
                 struct_span_err!(
                     tcx.sess,
                     first_item_span,
@@ -769,43 +756,27 @@ fn check_impl_items_against_trait<'tcx>(
 
     let trait_def = tcx.trait_def(impl_trait_ref.def_id);
 
-    for impl_item in impl_item_refs {
+    for &impl_item in impl_item_refs {
-        let ty_impl_item = tcx.associated_item(impl_item.id.owner_id);
+        let ty_impl_item = tcx.associated_item(impl_item);
         let ty_trait_item = if let Some(trait_item_id) = ty_impl_item.trait_item_def_id {
             tcx.associated_item(trait_item_id)
         } else {
             // Checked in `associated_item`.
-            tcx.sess.delay_span_bug(impl_item.span, "missing associated item in trait");
+            tcx.sess.delay_span_bug(tcx.def_span(impl_item), "missing associated item in trait");
             continue;
         };
-        let impl_item_full = tcx.hir().impl_item(impl_item.id);
+        match ty_impl_item.kind {
-        match impl_item_full.kind {
+            ty::AssocKind::Const => {
-            hir::ImplItemKind::Const(..) => {
                 let _ = tcx.compare_impl_const((
-                    impl_item.id.owner_id.def_id,
+                    impl_item.expect_local(),
                     ty_impl_item.trait_item_def_id.unwrap(),
                 ));
             }
-            hir::ImplItemKind::Fn(..) => {
+            ty::AssocKind::Fn => {
-                let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id);
+                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_ref,
-                    opt_trait_span,
-                );
             }
-            hir::ImplItemKind::Type(impl_ty) => {
+            ty::AssocKind::Type => {
-                let opt_trait_span = tcx.hir().span_if_local(ty_trait_item.def_id);
+                compare_impl_ty(tcx, &ty_impl_item, &ty_trait_item, impl_trait_ref);
-                compare_impl_ty(
-                    tcx,
-                    &ty_impl_item,
-                    impl_ty.span,
-                    &ty_trait_item,
-                    impl_trait_ref,
-                    opt_trait_span,
-                );
             }
         }
 
@@ -840,6 +811,8 @@ fn check_impl_items_against_trait<'tcx>(
                 .map_or(false, |node_item| !node_item.defining_node.is_from_trait());
 
             if !is_implemented_here {
+                let full_impl_span =
+                    tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(impl_id));
                 match tcx.eval_default_body_stability(trait_item_id, full_impl_span) {
                     EvalResult::Deny { feature, reason, issue, .. } => default_body_is_unstable(
                         tcx,
@@ -866,6 +839,8 @@ fn check_impl_items_against_trait<'tcx>(
         }
 
         if !missing_items.is_empty() {
+            let full_impl_span =
+                tcx.hir().span_with_body(tcx.hir().local_def_id_to_hir_id(impl_id));
             missing_items_err(tcx, tcx.def_span(impl_id), &missing_items, full_impl_span);
         }
 

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -33,7 +33,6 @@ use std::iter;
 /// # Parameters
 ///
 /// - `impl_m`: type of the method we are checking
-/// - `impl_m_span`: span to use for reporting errors
 /// - `trait_m`: the method in the trait
 /// - `impl_trait_ref`: the TraitRef corresponding to the trait implementation
 pub(super) fn compare_impl_method<'tcx>(
@@ -41,23 +40,19 @@ pub(super) fn compare_impl_method<'tcx>(
     impl_m: &ty::AssocItem,
     trait_m: &ty::AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
-    trait_item_span: Option<Span>,
 ) {
     debug!("compare_impl_method(impl_trait_ref={:?})", impl_trait_ref);
 
-    let impl_m_span = tcx.def_span(impl_m.def_id);
-
     let _: Result<_, ErrorGuaranteed> = try {
-        compare_self_type(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref)?;
+        compare_self_type(tcx, impl_m, trait_m, impl_trait_ref)?;
-        compare_number_of_generics(tcx, impl_m, trait_m, trait_item_span, false)?;
+        compare_number_of_generics(tcx, impl_m, trait_m, false)?;
         compare_generic_param_kinds(tcx, impl_m, trait_m, false)?;
-        compare_number_of_method_arguments(tcx, impl_m, impl_m_span, trait_m, trait_item_span)?;
+        compare_number_of_method_arguments(tcx, impl_m, trait_m)?;
         compare_synthetic_generics(tcx, impl_m, trait_m)?;
-        compare_asyncness(tcx, impl_m, impl_m_span, trait_m, trait_item_span)?;
+        compare_asyncness(tcx, impl_m, trait_m)?;
         compare_method_predicate_entailment(
             tcx,
             impl_m,
-            impl_m_span,
             trait_m,
             impl_trait_ref,
             CheckImpliedWfMode::Check,
@@ -131,11 +126,10 @@ pub(super) fn compare_impl_method<'tcx>(
 ///
 /// Finally we register each of these predicates as an obligation and check that
 /// they hold.
-#[instrument(level = "debug", skip(tcx, impl_m_span, impl_trait_ref))]
+#[instrument(level = "debug", skip(tcx, impl_trait_ref))]
 fn compare_method_predicate_entailment<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_m: &ty::AssocItem,
-    impl_m_span: Span,
     trait_m: &ty::AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
     check_implied_wf: CheckImpliedWfMode,
@@ -148,6 +142,7 @@ fn compare_method_predicate_entailment<'tcx>(
     // FIXME(@lcnr): remove that after removing `cause.body_id` from
     // obligations.
     let impl_m_def_id = impl_m.def_id.expect_local();
+    let impl_m_span = tcx.def_span(impl_m_def_id);
     let cause = ObligationCause::new(
         impl_m_span,
         impl_m_def_id,
@@ -315,7 +310,6 @@ fn compare_method_predicate_entailment<'tcx>(
                 return compare_method_predicate_entailment(
                     tcx,
                     impl_m,
-                    impl_m_span,
                     trait_m,
                     impl_trait_ref,
                     CheckImpliedWfMode::Skip,
@@ -353,7 +347,6 @@ fn compare_method_predicate_entailment<'tcx>(
                 return compare_method_predicate_entailment(
                     tcx,
                     impl_m,
-                    impl_m_span,
                     trait_m,
                     impl_trait_ref,
                     CheckImpliedWfMode::Skip,
@@ -535,9 +528,7 @@ enum CheckImpliedWfMode {
 fn compare_asyncness<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_m: &ty::AssocItem,
-    impl_m_span: Span,
     trait_m: &ty::AssocItem,
-    trait_item_span: Option<Span>,
 ) -> Result<(), ErrorGuaranteed> {
     if tcx.asyncness(trait_m.def_id) == hir::IsAsync::Async {
         match tcx.fn_sig(impl_m.def_id).skip_binder().skip_binder().output().kind() {
@@ -549,9 +540,9 @@ fn compare_asyncness<'tcx>(
             }
             _ => {
                 return Err(tcx.sess.emit_err(crate::errors::AsyncTraitImplShouldBeAsync {
-                    span: impl_m_span,
+                    span: tcx.def_span(impl_m.def_id),
                     method_name: trait_m.name,
-                    trait_item_span,
+                    trait_item_span: tcx.hir().span_if_local(trait_m.def_id),
                 }));
             }
         };
@@ -606,7 +597,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
 
     // First, check a few of the same things as `compare_impl_method`,
     // just so we don't ICE during substitution later.
-    compare_number_of_generics(tcx, impl_m, trait_m, tcx.hir().span_if_local(impl_m.def_id), true)?;
+    compare_number_of_generics(tcx, impl_m, trait_m, true)?;
     compare_generic_param_kinds(tcx, impl_m, trait_m, true)?;
     check_region_bounds_on_impl_item(tcx, impl_m, trait_m, true)?;
 
@@ -1094,7 +1085,6 @@ fn extract_spans_for_error_reporting<'tcx>(
 fn compare_self_type<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_m: &ty::AssocItem,
-    impl_m_span: Span,
     trait_m: &ty::AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
 ) -> Result<(), ErrorGuaranteed> {
@@ -1130,6 +1120,7 @@ fn compare_self_type<'tcx>(
 
         (false, true) => {
             let self_descr = self_string(impl_m);
+            let impl_m_span = tcx.def_span(impl_m.def_id);
             let mut err = struct_span_err!(
                 tcx.sess,
                 impl_m_span,
@@ -1149,6 +1140,7 @@ fn compare_self_type<'tcx>(
 
         (true, false) => {
             let self_descr = self_string(trait_m);
+            let impl_m_span = tcx.def_span(impl_m.def_id);
             let mut err = struct_span_err!(
                 tcx.sess,
                 impl_m_span,
@@ -1196,7 +1188,6 @@ fn compare_number_of_generics<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_: &ty::AssocItem,
     trait_: &ty::AssocItem,
-    trait_span: Option<Span>,
     delay: bool,
 ) -> Result<(), ErrorGuaranteed> {
     let trait_own_counts = tcx.generics_of(trait_.def_id).own_counts();
@@ -1256,6 +1247,7 @@ fn compare_number_of_generics<'tcx>(
                     .collect();
                 (Some(arg_spans), impl_trait_spans)
             } else {
+                let trait_span = tcx.hir().span_if_local(trait_.def_id);
                 (trait_span.map(|s| vec![s]), vec![])
             };
 
@@ -1338,9 +1330,7 @@ fn compare_number_of_generics<'tcx>(
 fn compare_number_of_method_arguments<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_m: &ty::AssocItem,
-    impl_m_span: Span,
     trait_m: &ty::AssocItem,
-    trait_item_span: Option<Span>,
 ) -> Result<(), ErrorGuaranteed> {
     let impl_m_fty = tcx.fn_sig(impl_m.def_id);
     let trait_m_fty = tcx.fn_sig(trait_m.def_id);
@@ -1362,7 +1352,7 @@ fn compare_number_of_method_arguments<'tcx>(
                     }
                 })
             })
-            .or(trait_item_span);
+            .or_else(|| tcx.hir().span_if_local(trait_m.def_id));
 
         let (impl_m_sig, _) = &tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).expect_fn();
         let pos = impl_number_args.saturating_sub(1);
@@ -1377,7 +1367,7 @@ fn compare_number_of_method_arguments<'tcx>(
                     arg.span.with_lo(impl_m_sig.decl.inputs[0].span.lo())
                 }
             })
-            .unwrap_or(impl_m_span);
+            .unwrap_or_else(|| tcx.def_span(impl_m.def_id));
 
         let mut err = struct_span_err!(
             tcx.sess,
@@ -1747,22 +1737,16 @@ pub(super) fn compare_impl_const_raw(
 pub(super) fn compare_impl_ty<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_ty: &ty::AssocItem,
-    impl_ty_span: Span,
     trait_ty: &ty::AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
-    trait_item_span: Option<Span>,
 ) {
     debug!("compare_impl_type(impl_trait_ref={:?})", impl_trait_ref);
 
     let _: Result<(), ErrorGuaranteed> = try {
-        compare_number_of_generics(tcx, impl_ty, trait_ty, trait_item_span, false)?;
+        compare_number_of_generics(tcx, impl_ty, trait_ty, false)?;
-
         compare_generic_param_kinds(tcx, impl_ty, trait_ty, false)?;
-
+        compare_type_predicate_entailment(tcx, impl_ty, trait_ty, impl_trait_ref)?;
-        let sp = tcx.def_span(impl_ty.def_id);
+        check_type_bounds(tcx, trait_ty, impl_ty, impl_trait_ref)?;
-        compare_type_predicate_entailment(tcx, impl_ty, sp, trait_ty, impl_trait_ref)?;
-
-        check_type_bounds(tcx, trait_ty, impl_ty, impl_ty_span, impl_trait_ref)?;
     };
 }
 
@@ -1771,7 +1755,6 @@ pub(super) fn compare_impl_ty<'tcx>(
 fn compare_type_predicate_entailment<'tcx>(
     tcx: TyCtxt<'tcx>,
     impl_ty: &ty::AssocItem,
-    impl_ty_span: Span,
     trait_ty: &ty::AssocItem,
     impl_trait_ref: ty::TraitRef<'tcx>,
 ) -> Result<(), ErrorGuaranteed> {
@@ -1808,6 +1791,7 @@ fn compare_type_predicate_entailment<'tcx>(
 
     debug!("compare_type_predicate_entailment: bounds={:?}", hybrid_preds);
 
+    let impl_ty_span = tcx.def_span(impl_ty_def_id);
     let normalize_cause = traits::ObligationCause::misc(impl_ty_span, impl_ty_def_id);
     let param_env = ty::ParamEnv::new(
         tcx.intern_predicates(&hybrid_preds.predicates),
@@ -1873,7 +1857,6 @@ pub(super) fn check_type_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     trait_ty: &ty::AssocItem,
     impl_ty: &ty::AssocItem,
-    impl_ty_span: Span,
     impl_trait_ref: ty::TraitRef<'tcx>,
 ) -> Result<(), ErrorGuaranteed> {
     // Given
@@ -2009,8 +1992,15 @@ pub(super) fn check_type_bounds<'tcx>(
     let infcx = tcx.infer_ctxt().build();
     let ocx = ObligationCtxt::new(&infcx);
 
-    let assumed_wf_types =
+    let impl_ty_span = match tcx.hir().get_by_def_id(impl_ty_def_id) {
-        ocx.assumed_wf_types(param_env, impl_ty_span, impl_ty.def_id.expect_local());
+        hir::Node::TraitItem(hir::TraitItem {
+            kind: hir::TraitItemKind::Type(_, Some(ty)),
+            ..
+        }) => ty.span,
+        hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Type(ty), .. }) => ty.span,
+        _ => bug!(),
+    };
+    let assumed_wf_types = ocx.assumed_wf_types(param_env, impl_ty_span, impl_ty_def_id);
 
     let normalize_cause = ObligationCause::new(
         impl_ty_span,

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -75,7 +75,6 @@ pub use check::check_abi;
 use check::check_mod_item_types;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder};
-use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_index::bit_set::BitSet;
@@ -169,27 +168,24 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt<'_>, id: LocalDefId) {
     }
 }
 
-fn report_forbidden_specialization(
+fn report_forbidden_specialization(tcx: TyCtxt<'_>, impl_item: DefId, parent_impl: DefId) {
-    tcx: TyCtxt<'_>,
+    let span = tcx.def_span(impl_item);
-    impl_item: &hir::ImplItemRef,
+    let ident = tcx.item_name(impl_item);
-    parent_impl: DefId,
-) {
     let mut err = struct_span_err!(
         tcx.sess,
-        impl_item.span,
+        span,
         E0520,
-        "`{}` specializes an item from a parent `impl`, but \
+        "`{}` specializes an item from a parent `impl`, but that item is not marked `default`",
-         that item is not marked `default`",
+        ident,
-        impl_item.ident
     );
-    err.span_label(impl_item.span, format!("cannot specialize default item `{}`", impl_item.ident));
+    err.span_label(span, format!("cannot specialize default item `{}`", ident));
 
     match tcx.span_of_impl(parent_impl) {
         Ok(span) => {
             err.span_label(span, "parent `impl` is here");
             err.note(&format!(
                 "to specialize, `{}` in the parent `impl` must be marked `default`",
-                impl_item.ident
+                ident
             ));
         }
         Err(cname) => {

tests/rustdoc-ui/issue-105742.rs

@@ -3,38 +3,17 @@
 use std::ops::Index;
 
 pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
-//~^ ERROR
-//~^^ ERROR
-//~^^^ ERROR
     let _ = s;
 }
 
 pub trait SVec: Index<
     <Self as SVec>::Item,
-//~^ ERROR
-//~^^ ERROR
-//~^^^ ERROR
-//~^^^^ ERROR
     Output = <Index<<Self as SVec>::Item,
-//~^ ERROR
-//~^^ ERROR
-//~^^^ ERROR
-//~^^^^ ERROR
     Output = <Self as SVec>::Item> as SVec>::Item,
-//~^ ERROR
-//~^^ ERROR
-//~^^^ ERROR
-//~^^^^ ERROR
-//~^^^^^ ERROR
-//~^^^^^^ ERROR
-//~^^^^^^^ ERROR
-//~^^^^^^^^ ERROR
 > {
     type Item<'a, T>;
 
     fn len(&self) -> <Self as SVec>::Item;
     //~^ ERROR
     //~^^ ERROR
-    //~^^^ ERROR
-    //~^^^^ ERROR
 }

tests/rustdoc-ui/issue-105742.stderr

@@ -1,328 +1,11 @@
 error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:13:21
+  --> $DIR/issue-105742.rs:16:38
-   |
-LL |     <Self as SVec>::Item,
-   |                     ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     <Self as SVec>::Item<'a>,
-   |                         ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:13:21
-   |
-LL |     <Self as SVec>::Item,
-   |                     ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     <Self as SVec>::Item<T>,
-   |                         +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:18:37
-   |
-LL |     Output = <Index<<Self as SVec>::Item,
-   |                                     ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Index<<Self as SVec>::Item<'a>,
-   |                                         ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:18:37
-   |
-LL |     Output = <Index<<Self as SVec>::Item,
-   |                                     ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Index<<Self as SVec>::Item<T>,
-   |                                         +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:30
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                              ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
-   |                                  ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:30
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                              ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
-   |                                  +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:46
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                                              ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
-   |                                                  ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:46
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                                              ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
-   |                                                  +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:5:40
-   |
-LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
-   |                                        ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item<'_> = T, Output = T>) {
-   |                                            ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:5:40
-   |
-LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
-   |                                        ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item<T> = T, Output = T>) {
-   |                                            +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:13:21
-   |
-LL |     <Self as SVec>::Item,
-   |                     ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     <Self as SVec>::Item<'a>,
-   |                         ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:13:21
-   |
-LL |     <Self as SVec>::Item,
-   |                     ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     <Self as SVec>::Item<T>,
-   |                         +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:18:37
-   |
-LL |     Output = <Index<<Self as SVec>::Item,
-   |                                     ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Index<<Self as SVec>::Item<'a>,
-   |                                         ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:18:37
-   |
-LL |     Output = <Index<<Self as SVec>::Item,
-   |                                     ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Index<<Self as SVec>::Item<T>,
-   |                                         +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:30
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                              ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Self as SVec>::Item<'a>> as SVec>::Item,
-   |                                  ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:30
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                              ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Self as SVec>::Item<T>> as SVec>::Item,
-   |                                  +++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:46
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                                              ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item<'a>,
-   |                                                  ++++
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:23:46
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item,
-   |                                              ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     Output = <Self as SVec>::Item> as SVec>::Item<T>,
-   |                                                  +++
-
-error[E0038]: the trait `SVec` cannot be made into an object
-  --> $DIR/issue-105742.rs:5:31
-   |
-LL | pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {
-   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `SVec` cannot be made into an object
-   |
-note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/issue-105742.rs:12:17
-   |
-LL |    pub trait SVec: Index<
-   |  ____________----__^
-   | |            |
-   | |            this trait cannot be made into an object...
-LL | |      <Self as SVec>::Item,
-LL | |
-LL | |
-...  |
-LL | |/     Output = <Index<<Self as SVec>::Item,
-LL | ||
-LL | ||
-LL | ||
-LL | ||
-LL | ||     Output = <Self as SVec>::Item> as SVec>::Item,
-   | ||_________________________________________________^ ...because it uses `Self` as a type parameter
-...  |
-LL | |
-LL | |  > {
-   | |__^ ...because it uses `Self` as a type parameter
-
-error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:35:38
    |
 LL |     fn len(&self) -> <Self as SVec>::Item;
    |                                      ^^^^ expected 1 lifetime argument
    |
 note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
+  --> $DIR/issue-105742.rs:14:10
    |
 LL |     type Item<'a, T>;
    |          ^^^^ --
@@ -332,13 +15,13 @@ LL |     fn len(&self) -> <Self as SVec>::Item<'_>;
    |                                          ++++
 
 error[E0107]: missing generics for associated type `SVec::Item`
-  --> $DIR/issue-105742.rs:35:38
+  --> $DIR/issue-105742.rs:16:38
    |
 LL |     fn len(&self) -> <Self as SVec>::Item;
    |                                      ^^^^ expected 1 generic argument
    |
 note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
+  --> $DIR/issue-105742.rs:14:10
    |
 LL |     type Item<'a, T>;
    |          ^^^^     -
@@ -347,39 +30,6 @@ help: add missing generic argument
 LL |     fn len(&self) -> <Self as SVec>::Item<T>;
    |                                          +++
 
-error[E0107]: missing generics for associated type `SVec::Item`
+error: aborting due to 2 previous errors
-  --> $DIR/issue-105742.rs:35:38
-   |
-LL |     fn len(&self) -> <Self as SVec>::Item;
-   |                                      ^^^^ expected 1 lifetime argument
-   |
-note: associated type defined here, with 1 lifetime parameter: `'a`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^ --
-help: add missing lifetime argument
-   |
-LL |     fn len(&self) -> <Self as SVec>::Item<'_>;
-   |                                          ++++
 
-error[E0107]: missing generics for associated type `SVec::Item`
+For more information about this error, try `rustc --explain E0107`.
-  --> $DIR/issue-105742.rs:35:38
-   |
-LL |     fn len(&self) -> <Self as SVec>::Item;
-   |                                      ^^^^ expected 1 generic argument
-   |
-note: associated type defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-105742.rs:33:10
-   |
-LL |     type Item<'a, T>;
-   |          ^^^^     -
-help: add missing generic argument
-   |
-LL |     fn len(&self) -> <Self as SVec>::Item<T>;
-   |                                          +++
-
-error: aborting due to 23 previous errors
-
-Some errors have detailed explanations: E0038, E0107.
-For more information about an error, try `rustc --explain E0038`.

tests/ui/error-codes/E0520.stderr

@@ -15,7 +15,7 @@ LL | impl<T: Clone> SpaceLlama for T {
    | ------------------------------- parent `impl` is here
 ...
 LL |     default fn fly(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `fly`
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `fly`
    |
    = note: to specialize, `fly` in the parent `impl` must be marked `default`
 

tests/ui/specialization/defaultimpl/specialization-no-default.stderr

@@ -15,7 +15,7 @@ LL | impl<T> Foo for T {
    | ----------------- parent `impl` is here
 ...
 LL |     fn foo(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `foo`
    |
    = note: to specialize, `foo` in the parent `impl` must be marked `default`
 
@@ -26,7 +26,7 @@ LL | impl<T> Foo for T {
    | ----------------- parent `impl` is here
 ...
 LL |     fn bar(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `bar`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `bar`
    |
    = note: to specialize, `bar` in the parent `impl` must be marked `default`
 
@@ -37,7 +37,7 @@ LL | impl<T> Bar for T {
    | ----------------- parent `impl` is here
 ...
 LL |     type T = ();
-   |     ^^^^^^^^^^^^ cannot specialize default item `T`
+   |     ^^^^^^ cannot specialize default item `T`
    |
    = note: to specialize, `T` in the parent `impl` must be marked `default`
 
@@ -48,7 +48,7 @@ LL | impl<T: Clone> Baz for T {
    | ------------------------ parent `impl` is here
 ...
 LL |     fn baz(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `baz`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `baz`
    |
    = note: to specialize, `baz` in the parent `impl` must be marked `default`
 
@@ -59,7 +59,7 @@ LL | impl<T: Clone> Redundant for T {
    | ------------------------------ parent `impl` is here
 ...
 LL |     fn redundant(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `redundant`
+   |     ^^^^^^^^^^^^^^^^^^^ cannot specialize default item `redundant`
    |
    = note: to specialize, `redundant` in the parent `impl` must be marked `default`
 

tests/ui/specialization/issue-50452-fail.stderr

@@ -12,7 +12,7 @@ error[E0520]: `foo` specializes an item from a parent `impl`, but that item is n
   --> $DIR/issue-50452-fail.rs:10:5
    |
 LL |     fn foo() {}
-   |     ^^^^^^^^^^^ cannot specialize default item `foo`
+   |     ^^^^^^^^ cannot specialize default item `foo`
 ...
 LL | impl<T> Foo for T {
    | ----------------- parent `impl` is here

tests/ui/specialization/non-defaulted-item-fail.stderr

@@ -15,7 +15,7 @@ LL | impl<T> Foo for Box<T> {
    | ---------------------- parent `impl` is here
 ...
 LL |     type Ty = Vec<()>;
-   |     ^^^^^^^^^^^^^^^^^^ cannot specialize default item `Ty`
+   |     ^^^^^^^ cannot specialize default item `Ty`
    |
    = note: to specialize, `Ty` in the parent `impl` must be marked `default`
 
@@ -26,7 +26,7 @@ LL | impl<T> Foo for Box<T> {
    | ---------------------- parent `impl` is here
 ...
 LL |     const CONST: u8 = 42;
-   |     ^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `CONST`
+   |     ^^^^^^^^^^^^^^^ cannot specialize default item `CONST`
    |
    = note: to specialize, `CONST` in the parent `impl` must be marked `default`
 
@@ -37,7 +37,7 @@ LL | impl<T> Foo for Box<T> {
    | ---------------------- parent `impl` is here
 ...
 LL |     fn foo(&self) -> bool { true }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
    |
    = note: to specialize, `foo` in the parent `impl` must be marked `default`
 
@@ -48,7 +48,7 @@ LL | impl<T> Foo for Vec<T> {}
    | ---------------------- parent `impl` is here
 ...
 LL |     type Ty = Vec<()>;
-   |     ^^^^^^^^^^^^^^^^^^ cannot specialize default item `Ty`
+   |     ^^^^^^^ cannot specialize default item `Ty`
    |
    = note: to specialize, `Ty` in the parent `impl` must be marked `default`
 
@@ -59,7 +59,7 @@ LL | impl<T> Foo for Vec<T> {}
    | ---------------------- parent `impl` is here
 ...
 LL |     const CONST: u8 = 42;
-   |     ^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `CONST`
+   |     ^^^^^^^^^^^^^^^ cannot specialize default item `CONST`
    |
    = note: to specialize, `CONST` in the parent `impl` must be marked `default`
 
@@ -70,7 +70,7 @@ LL | impl<T> Foo for Vec<T> {}
    | ---------------------- parent `impl` is here
 ...
 LL |     fn foo(&self) -> bool { true }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
+   |     ^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
    |
    = note: to specialize, `foo` in the parent `impl` must be marked `default`
 

tests/ui/specialization/specialization-no-default.stderr

@@ -15,7 +15,7 @@ LL | impl<T> Foo for T {
    | ----------------- parent `impl` is here
 ...
 LL |     fn foo(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `foo`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `foo`
    |
    = note: to specialize, `foo` in the parent `impl` must be marked `default`
 
@@ -26,7 +26,7 @@ LL | impl<T> Foo for T {
    | ----------------- parent `impl` is here
 ...
 LL |     fn bar(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `bar`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `bar`
    |
    = note: to specialize, `bar` in the parent `impl` must be marked `default`
 
@@ -37,7 +37,7 @@ LL | impl<T> Bar for T {
    | ----------------- parent `impl` is here
 ...
 LL |     type T = ();
-   |     ^^^^^^^^^^^^ cannot specialize default item `T`
+   |     ^^^^^^ cannot specialize default item `T`
    |
    = note: to specialize, `T` in the parent `impl` must be marked `default`
 
@@ -48,7 +48,7 @@ LL | impl<T: Clone> Baz for T {
    | ------------------------ parent `impl` is here
 ...
 LL |     fn baz(&self) {}
-   |     ^^^^^^^^^^^^^^^^ cannot specialize default item `baz`
+   |     ^^^^^^^^^^^^^ cannot specialize default item `baz`
    |
    = note: to specialize, `baz` in the parent `impl` must be marked `default`
 
@@ -59,7 +59,7 @@ LL | impl<T: Clone> Redundant for T {
    | ------------------------------ parent `impl` is here
 ...
 LL |     default fn redundant(&self) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `redundant`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `redundant`
    |
    = note: to specialize, `redundant` in the parent `impl` must be marked `default`
 

tests/ui/traits/negative-impls/no-items.stderr

@@ -2,7 +2,7 @@ error[E0749]: negative impls cannot have any items
   --> $DIR/no-items.rs:8:5
    |
 LL |     type Foo = i32;
-   |     ^^^^^^^^^^^^^^^
+   |     ^^^^^^^^
 
 error: aborting due to previous error