Rollup of 7 pull requests

compiler/rustc_data_structures/src/profiling.rs

@@ -142,7 +142,7 @@ const EVENT_FILTERS_BY_NAME: &[(&str, EventFilter)] = &[
     ("generic-activity", EventFilter::GENERIC_ACTIVITIES),
     ("query-provider", EventFilter::QUERY_PROVIDERS),
     ("query-cache-hit", EventFilter::QUERY_CACHE_HITS),
-    ("query-cache-hit-count", EventFilter::QUERY_CACHE_HITS),
+    ("query-cache-hit-count", EventFilter::QUERY_CACHE_HIT_COUNTS),
     ("query-blocked", EventFilter::QUERY_BLOCKED),
     ("incr-cache-load", EventFilter::INCR_CACHE_LOADS),
     ("query-keys", EventFilter::QUERY_KEYS),

compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs

@@ -184,9 +184,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     return true;
                 }
 
-                for param in [param_to_point_at, fallback_param_to_point_at, self_param_to_point_at]
-                    .into_iter()
-                    .flatten()
+                for param in [
+                    predicate_self_type_to_point_at,
+                    param_to_point_at,
+                    fallback_param_to_point_at,
+                    self_param_to_point_at,
+                ]
+                .into_iter()
+                .flatten()
                 {
                     if self.blame_specific_arg_if_possible(
                         error,

compiler/rustc_middle/src/traits/select.rs

@@ -97,20 +97,15 @@ pub type EvaluationCache<'tcx, ENV> = Cache<(ENV, ty::PolyTraitPredicate<'tcx>),
 pub enum SelectionCandidate<'tcx> {
     /// A built-in implementation for the `Sized` trait. This is preferred
     /// over all other candidates.
-    SizedCandidate {
-        has_nested: bool,
-    },
+    SizedCandidate,
 
     /// A builtin implementation for some specific traits, used in cases
     /// where we cannot rely an ordinary library implementations.
     ///
     /// The most notable examples are `Copy` and `Clone`. This is also
     /// used for the `DiscriminantKind` and `Pointee` trait, both of which have
     /// an associated type.
-    BuiltinCandidate {
-        /// `false` if there are no *further* obligations.
-        has_nested: bool,
-    },
+    BuiltinCandidate,
 
     /// Implementation of transmutability trait.
     TransmutabilityCandidate,

compiler/rustc_parse/src/parser/mod.rs

@@ -1293,8 +1293,10 @@ impl<'a> Parser<'a> {
         let kind = if pat {
             let guar = self
                 .dcx()
-                .struct_span_err(blk_span, "`inline_const_pat` has been removed")
-                .with_help("use a named `const`-item or an `if`-guard instead")
+                .struct_span_err(blk_span, "const blocks cannot be used as patterns")
+                .with_help(
+                    "use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead",
+                )
                 .emit();
             ExprKind::Err(guar)
         } else {

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

@@ -80,11 +80,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 }
                 Some(LangItem::DiscriminantKind) => {
                     // `DiscriminantKind` is automatically implemented for every type.
-                    candidates.vec.push(BuiltinCandidate { has_nested: false });
+                    candidates.vec.push(BuiltinCandidate);
                 }
                 Some(LangItem::PointeeTrait) => {
                     // `Pointee` is automatically implemented for every type.
-                    candidates.vec.push(BuiltinCandidate { has_nested: false });
+                    candidates.vec.push(BuiltinCandidate);
                 }
                 Some(LangItem::Sized) => {
                     self.assemble_builtin_sized_candidate(
@@ -365,7 +365,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         {
             debug!(?self_ty, ?obligation, "assemble_fused_iterator_candidates",);
 
-            candidates.vec.push(BuiltinCandidate { has_nested: false });
+            candidates.vec.push(BuiltinCandidate);
         }
     }
 
@@ -810,7 +810,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         hir::Movability::Movable => {
                             // Movable coroutines are always `Unpin`, so add an
                             // unconditional builtin candidate.
-                            candidates.vec.push(BuiltinCandidate { has_nested: false });
+                            candidates.vec.push(BuiltinCandidate);
                         }
                     }
                 }
@@ -1122,10 +1122,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         sizedness: SizedTraitKind,
     ) {
         match self.sizedness_conditions(obligation, sizedness) {
-            BuiltinImplConditions::Where(nested) => {
-                candidates
-                    .vec
-                    .push(SizedCandidate { has_nested: !nested.skip_binder().is_empty() });
+            BuiltinImplConditions::Where(_nested) => {
+                candidates.vec.push(SizedCandidate);
             }
             BuiltinImplConditions::None => {}
             BuiltinImplConditions::Ambiguous => {
@@ -1143,10 +1141,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
         match conditions {
-            BuiltinImplConditions::Where(nested) => {
-                candidates
-                    .vec
-                    .push(BuiltinCandidate { has_nested: !nested.skip_binder().is_empty() });
+            BuiltinImplConditions::Where(_) => {
+                candidates.vec.push(BuiltinCandidate);
             }
             BuiltinImplConditions::None => {}
             BuiltinImplConditions::Ambiguous => {
@@ -1160,7 +1156,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         _obligation: &PolyTraitObligation<'tcx>,
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
-        candidates.vec.push(BuiltinCandidate { has_nested: false });
+        candidates.vec.push(BuiltinCandidate);
     }
 
     fn assemble_candidate_for_tuple(
@@ -1171,7 +1167,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
         match self_ty.kind() {
             ty::Tuple(_) => {
-                candidates.vec.push(BuiltinCandidate { has_nested: false });
+                candidates.vec.push(BuiltinCandidate);
             }
             ty::Infer(ty::TyVar(_)) => {
                 candidates.ambiguous = true;
@@ -1215,7 +1211,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let self_ty = self.infcx.resolve_vars_if_possible(obligation.self_ty());
 
         match self_ty.skip_binder().kind() {
-            ty::FnPtr(..) => candidates.vec.push(BuiltinCandidate { has_nested: false }),
+            ty::FnPtr(..) => candidates.vec.push(BuiltinCandidate),
             ty::Bool
             | ty::Char
             | ty::Int(_)

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

@@ -37,13 +37,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         candidate: SelectionCandidate<'tcx>,
     ) -> Result<Selection<'tcx>, SelectionError<'tcx>> {
         Ok(match candidate {
-            SizedCandidate { has_nested } => {
-                let data = self.confirm_builtin_candidate(obligation, has_nested);
+            SizedCandidate => {
+                let data = self.confirm_builtin_candidate(obligation);
                 ImplSource::Builtin(BuiltinImplSource::Misc, data)
             }
 
-            BuiltinCandidate { has_nested } => {
-                let data = self.confirm_builtin_candidate(obligation, has_nested);
+            BuiltinCandidate => {
+                let data = self.confirm_builtin_candidate(obligation);
                 ImplSource::Builtin(BuiltinImplSource::Misc, data)
             }
 
@@ -249,50 +249,47 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn confirm_builtin_candidate(
         &mut self,
         obligation: &PolyTraitObligation<'tcx>,
-        has_nested: bool,
     ) -> PredicateObligations<'tcx> {
-        debug!(?obligation, ?has_nested, "confirm_builtin_candidate");
-
+        debug!(?obligation, "confirm_builtin_candidate");
         let tcx = self.tcx();
-        let obligations = if has_nested {
-            let trait_def = obligation.predicate.def_id();
-            let conditions = match tcx.as_lang_item(trait_def) {
-                Some(LangItem::Sized) => {
-                    self.sizedness_conditions(obligation, SizedTraitKind::Sized)
-                }
-                Some(LangItem::MetaSized) => {
-                    self.sizedness_conditions(obligation, SizedTraitKind::MetaSized)
-                }
-                Some(LangItem::PointeeSized) => {
-                    bug!("`PointeeSized` is removing during lowering");
-                }
-                Some(LangItem::Copy | LangItem::Clone) => self.copy_clone_conditions(obligation),
-                Some(LangItem::FusedIterator) => self.fused_iterator_conditions(obligation),
-                other => bug!("unexpected builtin trait {trait_def:?} ({other:?})"),
-            };
-            let BuiltinImplConditions::Where(types) = conditions else {
-                bug!("obligation {:?} had matched a builtin impl but now doesn't", obligation);
-            };
-            let types = self.infcx.enter_forall_and_leak_universe(types);
-
-            let cause = obligation.derived_cause(ObligationCauseCode::BuiltinDerived);
-            self.collect_predicates_for_types(
-                obligation.param_env,
-                cause,
-                obligation.recursion_depth + 1,
-                trait_def,
-                types,
-            )
-        } else {
-            PredicateObligations::new()
+        let trait_def = obligation.predicate.def_id();
+        let conditions = match tcx.as_lang_item(trait_def) {
+            Some(LangItem::Sized) => self.sizedness_conditions(obligation, SizedTraitKind::Sized),
+            Some(LangItem::MetaSized) => {
+                self.sizedness_conditions(obligation, SizedTraitKind::MetaSized)
+            }
+            Some(LangItem::PointeeSized) => {
+                bug!("`PointeeSized` is removing during lowering");
+            }
+            Some(LangItem::Copy | LangItem::Clone) => self.copy_clone_conditions(obligation),
+            Some(LangItem::FusedIterator) => self.fused_iterator_conditions(obligation),
+            Some(
+                LangItem::Destruct
+                | LangItem::DiscriminantKind
+                | LangItem::FnPtrTrait
+                | LangItem::PointeeTrait
+                | LangItem::Tuple
+                | LangItem::Unpin,
+            ) => BuiltinImplConditions::Where(ty::Binder::dummy(vec![])),
+            other => bug!("unexpected builtin trait {trait_def:?} ({other:?})"),
         };
+        let BuiltinImplConditions::Where(types) = conditions else {
+            bug!("obligation {:?} had matched a builtin impl but now doesn't", obligation);
+        };
+        let types = self.infcx.enter_forall_and_leak_universe(types);
 
-        debug!(?obligations);
-
-        obligations
+        let cause = obligation.derived_cause(ObligationCauseCode::BuiltinDerived);
+        self.collect_predicates_for_types(
+            obligation.param_env,
+            cause,
+            obligation.recursion_depth + 1,
+            trait_def,
+            types,
+        )
     }
 
     #[instrument(level = "debug", skip(self))]

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

@@ -1834,7 +1834,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
 
         // We prefer `Sized` candidates over everything.
         let mut sized_candidates =
-            candidates.iter().filter(|c| matches!(c.candidate, SizedCandidate { has_nested: _ }));
+            candidates.iter().filter(|c| matches!(c.candidate, SizedCandidate));
         if let Some(sized_candidate) = sized_candidates.next() {
             // There should only ever be a single sized candidate
             // as they would otherwise overlap.
@@ -1986,8 +1986,8 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
             // Don't use impl candidates which overlap with other candidates.
             // This should pretty much only ever happen with malformed impls.
             if candidates.iter().all(|c| match c.candidate {
-                SizedCandidate { has_nested: _ }
-                | BuiltinCandidate { has_nested: _ }
+                SizedCandidate
+                | BuiltinCandidate
                 | TransmutabilityCandidate
                 | AutoImplCandidate
                 | ClosureCandidate { .. }

compiler/rustc_ty_utils/src/assoc.rs

@@ -177,6 +177,17 @@ impl<'tcx> Visitor<'tcx> for RPITVisitor<'tcx> {
     }
 }
 
+struct DisambiguatorIdxVisitor {
+    depth: u32,
+}
+
+impl<'tcx> Visitor<'tcx> for DisambiguatorIdxVisitor {
+    fn visit_opaque_ty(&mut self, opaque: &'tcx hir::OpaqueTy<'tcx>) -> Self::Result {
+        self.depth += 1;
+        intravisit::walk_opaque_ty(self, opaque)
+    }
+}
+
 /// Given an `fn_def_id` of a trait or a trait implementation:
 ///
 /// if `fn_def_id` is a function defined inside a trait, then it synthesizes
@@ -211,16 +222,19 @@ fn associated_types_for_impl_traits_in_associated_fn(
                 let disambiguator_idx = trait_item_refs
                     .iter()
                     .take_while(|item| item.id.owner_id.def_id != fn_def_id)
-                    .fold(0, |acc, item| {
-                        if !matches!(item.kind, hir::AssocItemKind::Fn { .. }) {
-                            acc
-                        } else if def_path_id(item.id.owner_id.def_id) == def_path_data {
-                            tcx.def_key(item.id.owner_id.def_id).disambiguated_data.disambiguator
-                                + 1
-                        } else {
-                            acc
-                        }
-                    });
+                    .filter(|item| {
+                        matches!(item.kind, hir::AssocItemKind::Fn { .. })
+                            && def_path_id(item.id.owner_id.def_id) == def_path_data
+                    })
+                    .last()
+                    .map(|item| {
+                        let output = tcx.hir_get_fn_output(item.id.owner_id.def_id).unwrap();
+                        let mut visitor = DisambiguatorIdxVisitor { depth: 0 };
+                        visitor.visit_fn_ret_ty(output);
+                        tcx.def_key(item.id.owner_id.def_id).disambiguated_data.disambiguator
+                            + visitor.depth
+                    })
+                    .unwrap_or_default();
 
                 let data = DefPathData::AnonAssocTy(def_path_data);
                 let mut visitor = RPITVisitor {

library/alloc/src/string.rs

@@ -156,7 +156,7 @@ use crate::vec::{self, Vec};
 /// ```
 ///
 /// Next, what should `s[i]` return? Because indexing returns a reference
-/// to underlying data it could be `&u8`, `&[u8]`, or something else similar.
+/// to underlying data it could be `&u8`, `&[u8]`, or something similar.
 /// Since we're only providing one index, `&u8` makes the most sense but that
 /// might not be what the user expects and can be explicitly achieved with
 /// [`as_bytes()`]:
@@ -2875,7 +2875,8 @@ macro_rules! impl_to_string {
                     out = String::with_capacity(SIZE);
                 }
 
-                out.push_str(self.unsigned_abs()._fmt(&mut buf));
+                // SAFETY: `buf` is always big enough to contain all the digits.
+                unsafe { out.push_str(self.unsigned_abs()._fmt(&mut buf)); }
                 out
             }
         }
@@ -2887,7 +2888,8 @@ macro_rules! impl_to_string {
                 const SIZE: usize = $unsigned::MAX.ilog10() as usize + 1;
                 let mut buf = [core::mem::MaybeUninit::<u8>::uninit(); SIZE];
 
-                self._fmt(&mut buf).to_string()
+                // SAFETY: `buf` is always big enough to contain all the digits.
+                unsafe { self._fmt(&mut buf).to_string() }
             }
         }
         )*

library/alloctests/tests/lib.rs

@@ -9,6 +9,7 @@
 #![feature(downcast_unchecked)]
 #![feature(exact_size_is_empty)]
 #![feature(hashmap_internals)]
+#![feature(int_format_into)]
 #![feature(linked_list_cursors)]
 #![feature(map_try_insert)]
 #![feature(pattern)]