Rollup of 5 pull requests

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -6,6 +6,7 @@ use rustc_errors::{
     struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
 };
 use rustc_hir as hir;
+use rustc_hir::def::Res;
 use rustc_hir::intravisit::{walk_block, walk_expr, Visitor};
 use rustc_hir::{AsyncGeneratorKind, GeneratorKind, LangItem};
 use rustc_infer::infer::TyCtxtInferExt;
@@ -20,7 +21,7 @@ use rustc_middle::ty::{self, 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;
-use rustc_span::symbol::sym;
+use rustc_span::symbol::{kw, sym};
 use rustc_span::{BytePos, Span, Symbol};
 use rustc_trait_selection::infer::InferCtxtExt;
 
@@ -29,6 +30,7 @@ use crate::borrowck_errors;
 
 use crate::diagnostics::conflict_errors::StorageDeadOrDrop::LocalStorageDead;
 use crate::diagnostics::find_all_local_uses;
+use crate::diagnostics::mutability_errors::mut_borrow_of_mutable_ref;
 use crate::{
     borrow_set::BorrowData, diagnostics::Instance, prefixes::IsPrefixOf,
     InitializationRequiringAction, MirBorrowckCtxt, PrefixSet, WriteKind,
@@ -356,7 +358,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         if let Some(hir::Node::Item(hir::Item {
             kind: hir::ItemKind::Fn(_, _, body_id),
             ..
-        })) = hir.find(hir.local_def_id_to_hir_id(self.mir_def_id()))
+        })) = hir.find(self.mir_hir_id())
             && let Some(hir::Node::Expr(expr)) = hir.find(body_id.hir_id)
         {
             let place = &self.move_data.move_paths[mpi].place;
@@ -948,7 +950,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             }
             (BorrowKind::Mut { .. }, BorrowKind::Shared) => {
                 first_borrow_desc = "immutable ";
-                self.cannot_reborrow_already_borrowed(
+                let mut err = self.cannot_reborrow_already_borrowed(
                     span,
                     &desc_place,
                     &msg_place,
@@ -958,7 +960,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     "immutable",
                     &msg_borrow,
                     None,
-                )
+                );
+                self.suggest_binding_for_closure_capture_self(
+                    &mut err,
+                    issued_borrow.borrowed_place,
+                    &issued_spans,
+                );
+                err
             }
 
             (BorrowKind::Mut { .. }, BorrowKind::Mut { .. }) => {
@@ -1240,6 +1248,138 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         }
     }
 
+    fn suggest_binding_for_closure_capture_self(
+        &self,
+        err: &mut Diagnostic,
+        borrowed_place: Place<'tcx>,
+        issued_spans: &UseSpans<'tcx>,
+    ) {
+        let UseSpans::ClosureUse { capture_kind_span, .. } = issued_spans else { return };
+        let hir = self.infcx.tcx.hir();
+
+        // check whether the borrowed place is capturing `self` by mut reference
+        let local = borrowed_place.local;
+        let Some(_) = self
+            .body
+            .local_decls
+            .get(local)
+            .map(|l| mut_borrow_of_mutable_ref(l, self.local_names[local])) else { return };
+
+        struct ExpressionFinder<'hir> {
+            capture_span: Span,
+            closure_change_spans: Vec<Span>,
+            closure_arg_span: Option<Span>,
+            in_closure: bool,
+            suggest_arg: String,
+            hir: rustc_middle::hir::map::Map<'hir>,
+            closure_local_id: Option<hir::HirId>,
+            closure_call_changes: Vec<(Span, String)>,
+        }
+        impl<'hir> Visitor<'hir> for ExpressionFinder<'hir> {
+            fn visit_expr(&mut self, e: &'hir hir::Expr<'hir>) {
+                if e.span.contains(self.capture_span) {
+                    if let hir::ExprKind::Closure(&hir::Closure {
+                            movability: None,
+                            body,
+                            fn_arg_span,
+                            fn_decl: hir::FnDecl{ inputs, .. },
+                            ..
+                        }) = e.kind &&
+                        let Some(hir::Node::Expr(body )) = self.hir.find(body.hir_id) {
+                            self.suggest_arg = "this: &Self".to_string();
+                            if inputs.len() > 0 {
+                                self.suggest_arg.push_str(", ");
+                            }
+                            self.in_closure = true;
+                            self.closure_arg_span = fn_arg_span;
+                            self.visit_expr(body);
+                            self.in_closure = false;
+                    }
+                }
+                if let hir::Expr { kind: hir::ExprKind::Path(path), .. } = e {
+                    if let hir::QPath::Resolved(_, hir::Path { segments: [seg], ..}) = path &&
+                        seg.ident.name == kw::SelfLower && self.in_closure {
+                            self.closure_change_spans.push(e.span);
+                    }
+                }
+                hir::intravisit::walk_expr(self, e);
+            }
+
+            fn visit_local(&mut self, local: &'hir hir::Local<'hir>) {
+                if let hir::Pat { kind: hir::PatKind::Binding(_, hir_id, _ident, _), .. } = local.pat &&
+                    let Some(init) = local.init
+                {
+                    if let hir::Expr { kind: hir::ExprKind::Closure(&hir::Closure {
+                            movability: None,
+                            ..
+                        }), .. } = init &&
+                        init.span.contains(self.capture_span) {
+                            self.closure_local_id = Some(*hir_id);
+                    }
+                }
+                hir::intravisit::walk_local(self, local);
+            }
+
+            fn visit_stmt(&mut self, s: &'hir hir::Stmt<'hir>) {
+                if let hir::StmtKind::Semi(e) = s.kind &&
+                    let hir::ExprKind::Call(hir::Expr { kind: hir::ExprKind::Path(path), ..}, args) = e.kind &&
+                    let hir::QPath::Resolved(_, hir::Path { segments: [seg], ..}) = path &&
+                    let Res::Local(hir_id) = seg.res &&
+                        Some(hir_id) == self.closure_local_id {
+                        let (span, arg_str) = if args.len() > 0 {
+                            (args[0].span.shrink_to_lo(), "self, ".to_string())
+                        } else {
+                            let span = e.span.trim_start(seg.ident.span).unwrap_or(e.span);
+                            (span, "(self)".to_string())
+                        };
+                        self.closure_call_changes.push((span, arg_str));
+                }
+                hir::intravisit::walk_stmt(self, s);
+            }
+        }
+
+        if let Some(hir::Node::ImplItem(
+                    hir::ImplItem { kind: hir::ImplItemKind::Fn(_fn_sig, body_id), .. }
+                )) = hir.find(self.mir_hir_id()) &&
+            let Some(hir::Node::Expr(expr)) = hir.find(body_id.hir_id) {
+            let mut finder = ExpressionFinder {
+                capture_span: *capture_kind_span,
+                closure_change_spans: vec![],
+                closure_arg_span: None,
+                in_closure: false,
+                suggest_arg: String::new(),
+                closure_local_id: None,
+                closure_call_changes: vec![],
+                hir,
+            };
+            finder.visit_expr(expr);
+
+            if finder.closure_change_spans.is_empty() || finder.closure_call_changes.is_empty() {
+                return;
+            }
+
+            let mut sugg = vec![];
+            let sm = self.infcx.tcx.sess.source_map();
+
+            if let Some(span) = finder.closure_arg_span {
+                sugg.push((sm.next_point(span.shrink_to_lo()).shrink_to_hi(), finder.suggest_arg));
+            }
+            for span in finder.closure_change_spans {
+                sugg.push((span, "this".to_string()));
+            }
+
+            for (span, suggest) in finder.closure_call_changes {
+                sugg.push((span, suggest));
+            }
+
+            err.multipart_suggestion_verbose(
+                "try explicitly pass `&Self` into the Closure as an argument",
+                sugg,
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+
     /// Returns the description of the root place for a conflicting borrow and the full
     /// descriptions of the places that caused the conflict.
     ///

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -1094,7 +1094,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     }
 }
 
-fn mut_borrow_of_mutable_ref(local_decl: &LocalDecl<'_>, local_name: Option<Symbol>) -> bool {
+pub fn mut_borrow_of_mutable_ref(local_decl: &LocalDecl<'_>, local_name: Option<Symbol>) -> bool {
     debug!("local_info: {:?}, ty.kind(): {:?}", local_decl.local_info, local_decl.ty.kind());
 
     match local_decl.local_info.as_deref() {

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -165,11 +165,23 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
                 };
             e_flags
         }
-        Architecture::Riscv64 if sess.target.options.features.contains("+d") => {
-            // copied from `riscv64-linux-gnu-gcc foo.c -c`, note though
-            // that the `+d` target feature represents whether the double
-            // float abi is enabled.
-            let e_flags = elf::EF_RISCV_RVC | elf::EF_RISCV_FLOAT_ABI_DOUBLE;
+        Architecture::Riscv32 | Architecture::Riscv64 => {
+            // Source: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/079772828bd10933d34121117a222b4cc0ee2200/riscv-elf.adoc
+            let mut e_flags: u32 = 0x0;
+            let features = &sess.target.options.features;
+            // Check if compressed is enabled
+            if features.contains("+c") {
+                e_flags |= elf::EF_RISCV_RVC;
+            }
+
+            // Select the appropriate floating-point ABI
+            if features.contains("+d") {
+                e_flags |= elf::EF_RISCV_FLOAT_ABI_DOUBLE;
+            } else if features.contains("+f") {
+                e_flags |= elf::EF_RISCV_FLOAT_ABI_SINGLE;
+            } else {
+                e_flags |= elf::EF_RISCV_FLOAT_ABI_SOFT;
+            }
             e_flags
         }
         _ => 0,

compiler/rustc_error_messages/locales/en-US/interface.ftl

@@ -41,3 +41,6 @@ interface_rustc_error_unexpected_annotation =
 
 interface_failed_writing_file =
     failed to write file {$path}: {$error}"
+
+interface_proc_macro_crate_panic_abort =
+    building proc macro crate with `panic=abort` may crash the compiler should the proc-macro panic

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -2,7 +2,9 @@ use super::potentially_plural_count;
 use crate::errors::LifetimesOrBoundsMismatchOnTrait;
 use hir::def_id::{DefId, LocalDefId};
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
-use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed};
+use rustc_errors::{
+    pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed, MultiSpan,
+};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit;
@@ -320,15 +322,6 @@ fn compare_method_predicate_entailment<'tcx>(
             ty::Binder::dummy(ty::PredicateKind::WellFormed(unnormalized_impl_fty.into())),
         ));
     }
-    let emit_implied_wf_lint = || {
-        infcx.tcx.struct_span_lint_hir(
-            rustc_session::lint::builtin::IMPLIED_BOUNDS_ENTAILMENT,
-            impl_m_hir_id,
-            infcx.tcx.def_span(impl_m.def_id),
-            "impl method assumes more implied bounds than the corresponding trait method",
-            |lint| lint,
-        );
-    };
 
     // Check that all obligations are satisfied by the implementation's
     // version.
@@ -346,7 +339,7 @@ fn compare_method_predicate_entailment<'tcx>(
                 )
                 .map(|()| {
                     // If the skip-mode was successful, emit a lint.
-                    emit_implied_wf_lint();
+                    emit_implied_wf_lint(infcx.tcx, impl_m, impl_m_hir_id, vec![]);
                 });
             }
             CheckImpliedWfMode::Skip => {
@@ -382,8 +375,16 @@ fn compare_method_predicate_entailment<'tcx>(
                     CheckImpliedWfMode::Skip,
                 )
                 .map(|()| {
+                    let bad_args = extract_bad_args_for_implies_lint(
+                        tcx,
+                        &errors,
+                        (trait_m, trait_sig),
+                        // Unnormalized impl sig corresponds to the HIR types written
+                        (impl_m, unnormalized_impl_sig),
+                        impl_m_hir_id,
+                    );
                     // If the skip-mode was successful, emit a lint.
-                    emit_implied_wf_lint();
+                    emit_implied_wf_lint(tcx, impl_m, impl_m_hir_id, bad_args);
                 });
             }
             CheckImpliedWfMode::Skip => {
@@ -400,6 +401,141 @@ fn compare_method_predicate_entailment<'tcx>(
     Ok(())
 }
 
+fn extract_bad_args_for_implies_lint<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    errors: &[infer::RegionResolutionError<'tcx>],
+    (trait_m, trait_sig): (&ty::AssocItem, ty::FnSig<'tcx>),
+    (impl_m, impl_sig): (&ty::AssocItem, ty::FnSig<'tcx>),
+    hir_id: hir::HirId,
+) -> Vec<(Span, Option<String>)> {
+    let mut blame_generics = vec![];
+    for error in errors {
+        // Look for the subregion origin that contains an input/output type
+        let origin = match error {
+            infer::RegionResolutionError::ConcreteFailure(o, ..) => o,
+            infer::RegionResolutionError::GenericBoundFailure(o, ..) => o,
+            infer::RegionResolutionError::SubSupConflict(_, _, o, ..) => o,
+            infer::RegionResolutionError::UpperBoundUniverseConflict(.., o, _) => o,
+        };
+        // Extract (possible) input/output types from origin
+        match origin {
+            infer::SubregionOrigin::Subtype(trace) => {
+                if let Some((a, b)) = trace.values.ty() {
+                    blame_generics.extend([a, b]);
+                }
+            }
+            infer::SubregionOrigin::RelateParamBound(_, ty, _) => blame_generics.push(*ty),
+            infer::SubregionOrigin::ReferenceOutlivesReferent(ty, _) => blame_generics.push(*ty),
+            _ => {}
+        }
+    }
+
+    let fn_decl = tcx.hir().fn_decl_by_hir_id(hir_id).unwrap();
+    let opt_ret_ty = match fn_decl.output {
+        hir::FnRetTy::DefaultReturn(_) => None,
+        hir::FnRetTy::Return(ty) => Some(ty),
+    };
+
+    // Map late-bound regions from trait to impl, so the names are right.
+    let mapping = std::iter::zip(
+        tcx.fn_sig(trait_m.def_id).bound_vars(),
+        tcx.fn_sig(impl_m.def_id).bound_vars(),
+    )
+    .filter_map(|(impl_bv, trait_bv)| {
+        if let ty::BoundVariableKind::Region(impl_bv) = impl_bv
+            && let ty::BoundVariableKind::Region(trait_bv) = trait_bv
+        {
+            Some((impl_bv, trait_bv))
+        } else {
+            None
+        }
+    })
+    .collect();
+
+    // For each arg, see if it was in the "blame" of any of the region errors.
+    // If so, then try to produce a suggestion to replace the argument type with
+    // one from the trait.
+    let mut bad_args = vec![];
+    for (idx, (ty, hir_ty)) in
+        std::iter::zip(impl_sig.inputs_and_output, fn_decl.inputs.iter().chain(opt_ret_ty))
+            .enumerate()
+    {
+        let expected_ty = trait_sig.inputs_and_output[idx]
+            .fold_with(&mut RemapLateBound { tcx, mapping: &mapping });
+        if blame_generics.iter().any(|blame| ty.contains(*blame)) {
+            let expected_ty_sugg = expected_ty.to_string();
+            bad_args.push((
+                hir_ty.span,
+                // Only suggest something if it actually changed.
+                (expected_ty_sugg != ty.to_string()).then_some(expected_ty_sugg),
+            ));
+        }
+    }
+
+    bad_args
+}
+
+struct RemapLateBound<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
+    mapping: &'a FxHashMap<ty::BoundRegionKind, ty::BoundRegionKind>,
+}
+
+impl<'tcx> TypeFolder<'tcx> for RemapLateBound<'_, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
+    fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
+        if let ty::ReFree(fr) = *r {
+            self.tcx.mk_region(ty::ReFree(ty::FreeRegion {
+                bound_region: self
+                    .mapping
+                    .get(&fr.bound_region)
+                    .copied()
+                    .unwrap_or(fr.bound_region),
+                ..fr
+            }))
+        } else {
+            r
+        }
+    }
+}
+
+fn emit_implied_wf_lint<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    impl_m: &ty::AssocItem,
+    hir_id: hir::HirId,
+    bad_args: Vec<(Span, Option<String>)>,
+) {
+    let span: MultiSpan = if bad_args.is_empty() {
+        tcx.def_span(impl_m.def_id).into()
+    } else {
+        bad_args.iter().map(|(span, _)| *span).collect::<Vec<_>>().into()
+    };
+    tcx.struct_span_lint_hir(
+        rustc_session::lint::builtin::IMPLIED_BOUNDS_ENTAILMENT,
+        hir_id,
+        span,
+        "impl method assumes more implied bounds than the corresponding trait method",
+        |lint| {
+            let bad_args: Vec<_> =
+                bad_args.into_iter().filter_map(|(span, sugg)| Some((span, sugg?))).collect();
+            if !bad_args.is_empty() {
+                lint.multipart_suggestion(
+                    format!(
+                        "replace {} type{} to make the impl signature compatible",
+                        pluralize!("this", bad_args.len()),
+                        pluralize!(bad_args.len())
+                    ),
+                    bad_args,
+                    Applicability::MaybeIncorrect,
+                );
+            }
+            lint
+        },
+    );
+}
+
 #[derive(Debug, PartialEq, Eq)]
 enum CheckImpliedWfMode {
     /// Checks implied well-formedness of the impl method. If it fails, we will

compiler/rustc_interface/Cargo.toml

@@ -45,6 +45,7 @@ rustc_plugin_impl = { path = "../rustc_plugin_impl" }
 rustc_privacy = { path = "../rustc_privacy" }
 rustc_query_impl = { path = "../rustc_query_impl" }
 rustc_resolve = { path = "../rustc_resolve" }
+rustc_target = { path = "../rustc_target" }
 rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_ty_utils = { path = "../rustc_ty_utils" }
 

compiler/rustc_interface/src/errors.rs

@@ -87,3 +87,7 @@ pub struct FailedWritingFile<'a> {
     pub path: &'a Path,
     pub error: io::Error,
 }
+
+#[derive(Diagnostic)]
+#[diag(interface_proc_macro_crate_panic_abort)]
+pub struct ProcMacroCratePanicAbort;

compiler/rustc_interface/src/passes.rs

@@ -1,7 +1,8 @@
 use crate::errors::{
     CantEmitMIR, EmojiIdentifier, ErrorWritingDependencies, FerrisIdentifier,
     GeneratedFileConflictsWithDirectory, InputFileWouldBeOverWritten, MixedBinCrate,
-    MixedProcMacroCrate, OutDirError, ProcMacroDocWithoutArg, TempsDirError,
+    MixedProcMacroCrate, OutDirError, ProcMacroCratePanicAbort, ProcMacroDocWithoutArg,
+    TempsDirError,
 };
 use crate::interface::{Compiler, Result};
 use crate::proc_macro_decls;
@@ -36,6 +37,7 @@ use rustc_session::search_paths::PathKind;
 use rustc_session::{Limit, Session};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::FileName;
+use rustc_target::spec::PanicStrategy;
 use rustc_trait_selection::traits;
 
 use std::any::Any;
@@ -380,6 +382,10 @@ pub fn configure_and_expand(
         }
     }
 
+    if is_proc_macro_crate && sess.panic_strategy() == PanicStrategy::Abort {
+        sess.emit_warning(ProcMacroCratePanicAbort);
+    }
+
     // For backwards compatibility, we don't try to run proc macro injection
     // if rustdoc is run on a proc macro crate without '--crate-type proc-macro' being
     // specified. This should only affect users who manually invoke 'rustdoc', as

compiler/rustc_lint_defs/src/builtin.rs

@@ -4033,10 +4033,10 @@ declare_lint! {
     ///
     /// This can be used to implement an unsound API if used incorrectly.
     pub IMPLIED_BOUNDS_ENTAILMENT,
-    Warn,
+    Deny,
     "impl method assumes more implied bounds than its corresponding trait method",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #105572 <https://github.com/rust-lang/rust/issues/105572>",
-        reason: FutureIncompatibilityReason::FutureReleaseError,
+        reason: FutureIncompatibilityReason::FutureReleaseErrorReportNow,
     };
 }

library/std/src/sync/mpmc/array.rs

@@ -168,7 +168,7 @@ impl<T> Channel<T> {
                         return true;
                     }
                     Err(_) => {
-                        backoff.spin();
+                        backoff.spin_light();
                         tail = self.tail.load(Ordering::Relaxed);
                     }
                 }
@@ -182,11 +182,11 @@ impl<T> Channel<T> {
                     return false;
                 }
 
-                backoff.spin();
+                backoff.spin_light();
                 tail = self.tail.load(Ordering::Relaxed);
             } else {
                 // Snooze because we need to wait for the stamp to get updated.
-                backoff.snooze();
+                backoff.spin_heavy();
                 tail = self.tail.load(Ordering::Relaxed);
             }
         }
@@ -251,7 +251,7 @@ impl<T> Channel<T> {
                         return true;
                     }
                     Err(_) => {
-                        backoff.spin();
+                        backoff.spin_light();
                         head = self.head.load(Ordering::Relaxed);
                     }
                 }
@@ -273,11 +273,11 @@ impl<T> Channel<T> {
                     }
                 }
 
-                backoff.spin();
+                backoff.spin_light();
                 head = self.head.load(Ordering::Relaxed);
             } else {
                 // Snooze because we need to wait for the stamp to get updated.
-                backoff.snooze();
+                backoff.spin_heavy();
                 head = self.head.load(Ordering::Relaxed);
             }
         }
@@ -330,7 +330,7 @@ impl<T> Channel<T> {
                 if backoff.is_completed() {
                     break;
                 } else {
-                    backoff.spin();
+                    backoff.spin_light();
                 }
             }
 

library/std/src/sync/mpmc/list.rs

@@ -46,7 +46,7 @@ impl<T> Slot<T> {
     fn wait_write(&self) {
         let backoff = Backoff::new();
         while self.state.load(Ordering::Acquire) & WRITE == 0 {
-            backoff.snooze();
+            backoff.spin_heavy();
         }
     }
 }
@@ -82,7 +82,7 @@ impl<T> Block<T> {
             if !next.is_null() {
                 return next;
             }
-            backoff.snooze();
+            backoff.spin_heavy();
         }
     }
 
@@ -191,7 +191,7 @@ impl<T> Channel<T> {
 
             // If we reached the end of the block, wait until the next one is installed.
             if offset == BLOCK_CAP {
-                backoff.snooze();
+                backoff.spin_heavy();
                 tail = self.tail.index.load(Ordering::Acquire);
                 block = self.tail.block.load(Ordering::Acquire);
                 continue;
@@ -247,7 +247,7 @@ impl<T> Channel<T> {
                     return true;
                 },
                 Err(_) => {
-                    backoff.spin();
+                    backoff.spin_light();
                     tail = self.tail.index.load(Ordering::Acquire);
                     block = self.tail.block.load(Ordering::Acquire);
                 }
@@ -286,7 +286,7 @@ impl<T> Channel<T> {
 
             // If we reached the end of the block, wait until the next one is installed.
             if offset == BLOCK_CAP {
-                backoff.snooze();
+                backoff.spin_heavy();
                 head = self.head.index.load(Ordering::Acquire);
                 block = self.head.block.load(Ordering::Acquire);
                 continue;
@@ -320,7 +320,7 @@ impl<T> Channel<T> {
             // The block can be null here only if the first message is being sent into the channel.
             // In that case, just wait until it gets initialized.
             if block.is_null() {
-                backoff.snooze();
+                backoff.spin_heavy();
                 head = self.head.index.load(Ordering::Acquire);
                 block = self.head.block.load(Ordering::Acquire);
                 continue;
@@ -351,7 +351,7 @@ impl<T> Channel<T> {
                     return true;
                 },
                 Err(_) => {
-                    backoff.spin();
+                    backoff.spin_light();
                     head = self.head.index.load(Ordering::Acquire);
                     block = self.head.block.load(Ordering::Acquire);
                 }
@@ -542,7 +542,7 @@ impl<T> Channel<T> {
             // New updates to tail will be rejected by MARK_BIT and aborted unless it's
             // at boundary. We need to wait for the updates take affect otherwise there
             // can be memory leaks.
-            backoff.snooze();
+            backoff.spin_heavy();
             tail = self.tail.index.load(Ordering::Acquire);
         }
 

library/std/src/sync/mpmc/mod.rs

@@ -43,7 +43,7 @@ mod zero;
 use crate::fmt;
 use crate::panic::{RefUnwindSafe, UnwindSafe};
 use crate::time::{Duration, Instant};
-use error::*;
+pub use error::*;
 
 /// Creates a channel of unbounded capacity.
 ///

library/std/src/sync/mpmc/utils.rs

@@ -91,9 +91,8 @@ impl<T> DerefMut for CachePadded<T> {
 }
 
 const SPIN_LIMIT: u32 = 6;
-const YIELD_LIMIT: u32 = 10;
 
-/// Performs exponential backoff in spin loops.
+/// Performs quadratic backoff in spin loops.
 pub struct Backoff {
     step: Cell<u32>,
 }
@@ -104,25 +103,27 @@ impl Backoff {
         Backoff { step: Cell::new(0) }
     }
 
-    /// Backs off in a lock-free loop.
+    /// Backs off using lightweight spinning.
     ///
-    /// This method should be used when we need to retry an operation because another thread made
-    /// progress.
+    /// This method should be used for:
+    ///     - Retrying an operation because another thread made progress. i.e. on CAS failure.
+    ///     - Waiting for an operation to complete by spinning optimistically for a few iterations
+    ///     before falling back to parking the thread (see `Backoff::is_completed`).
     #[inline]
-    pub fn spin(&self) {
+    pub fn spin_light(&self) {
         let step = self.step.get().min(SPIN_LIMIT);
         for _ in 0..step.pow(2) {
             crate::hint::spin_loop();
         }
 
-        if self.step.get() <= SPIN_LIMIT {
-            self.step.set(self.step.get() + 1);
-        }
+        self.step.set(self.step.get() + 1);
     }
 
-    /// Backs off in a blocking loop.
+    /// Backs off using heavyweight spinning.
+    ///
+    /// This method should be used in blocking loops where parking the thread is not an option.
     #[inline]
-    pub fn snooze(&self) {
+    pub fn spin_heavy(&self) {
         if self.step.get() <= SPIN_LIMIT {
             for _ in 0..self.step.get().pow(2) {
                 crate::hint::spin_loop()
@@ -131,14 +132,12 @@ impl Backoff {
             crate::thread::yield_now();
         }
 
-        if self.step.get() <= YIELD_LIMIT {
-            self.step.set(self.step.get() + 1);
-        }
+        self.step.set(self.step.get() + 1);
     }
 
-    /// Returns `true` if quadratic backoff has completed and blocking the thread is advised.
+    /// Returns `true` if quadratic backoff has completed and parking the thread is advised.
     #[inline]
     pub fn is_completed(&self) -> bool {
-        self.step.get() > YIELD_LIMIT
+        self.step.get() > SPIN_LIMIT
     }
 }

library/std/src/sync/mpmc/zero.rs

@@ -57,7 +57,7 @@ impl<T> Packet<T> {
     fn wait_ready(&self) {
         let backoff = Backoff::new();
         while !self.ready.load(Ordering::Acquire) {
-            backoff.snooze();
+            backoff.spin_heavy();
         }
     }
 }

library/std/src/sync/mpsc/mod.rs

@@ -738,6 +738,15 @@ impl<T> SyncSender<T> {
     pub fn try_send(&self, t: T) -> Result<(), TrySendError<T>> {
         self.inner.try_send(t)
     }
+
+    // Attempts to send for a value on this receiver, returning an error if the
+    // corresponding channel has hung up, or if it waits more than `timeout`.
+    //
+    // This method is currently private and only used for tests.
+    #[allow(unused)]
+    fn send_timeout(&self, t: T, timeout: Duration) -> Result<(), mpmc::SendTimeoutError<T>> {
+        self.inner.send_timeout(t, timeout)
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

library/std/src/sync/mpsc/sync_tests.rs

@@ -1,5 +1,6 @@
 use super::*;
 use crate::env;
+use crate::sync::mpmc::SendTimeoutError;
 use crate::thread;
 use crate::time::Duration;
 
@@ -41,6 +42,13 @@ fn recv_timeout() {
     assert_eq!(rx.recv_timeout(Duration::from_millis(1)), Ok(1));
 }
 
+#[test]
+fn send_timeout() {
+    let (tx, _rx) = sync_channel::<i32>(1);
+    assert_eq!(tx.send_timeout(1, Duration::from_millis(1)), Ok(()));
+    assert_eq!(tx.send_timeout(1, Duration::from_millis(1)), Err(SendTimeoutError::Timeout(1)));
+}
+
 #[test]
 fn smoke_threads() {
     let (tx, rx) = sync_channel::<i32>(0);

tests/ui/implied-bounds/impl-implied-bounds-compatibility-unnormalized.stderr

@@ -1,8 +1,8 @@
 error: impl method assumes more implied bounds than the corresponding trait method
-  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:13:5
+  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:13:31
    |
 LL |     fn get<'s>(s: &'s str, _: <&'static &'s () as Project>::Ty) -> &'static str {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this type to make the impl signature compatible: `()`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #105572 <https://github.com/rust-lang/rust/issues/105572>
@@ -14,3 +14,18 @@ LL | #![deny(implied_bounds_entailment)]
 
 error: aborting due to previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:13:31
+   |
+LL |     fn get<'s>(s: &'s str, _: <&'static &'s () as Project>::Ty) -> &'static str {
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this type to make the impl signature compatible: `()`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #105572 <https://github.com/rust-lang/rust/issues/105572>
+note: the lint level is defined here
+  --> $DIR/impl-implied-bounds-compatibility-unnormalized.rs:1:9
+   |
+LL | #![deny(implied_bounds_entailment)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+

tests/ui/implied-bounds/impl-implied-bounds-compatibility.stderr

@@ -1,8 +1,8 @@
 error: impl method assumes more implied bounds than the corresponding trait method
-  --> $DIR/impl-implied-bounds-compatibility.rs:14:5
+  --> $DIR/impl-implied-bounds-compatibility.rs:14:35
    |
 LL |     fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this type to make the impl signature compatible: `&'b MessageListeners<'b>`
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #105572 <https://github.com/rust-lang/rust/issues/105572>
@@ -14,3 +14,18 @@ LL | #![deny(implied_bounds_entailment)]
 
 error: aborting due to previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: impl method assumes more implied bounds than the corresponding trait method
+  --> $DIR/impl-implied-bounds-compatibility.rs:14:35
+   |
+LL |     fn listeners<'b>(&'b self) -> &'a MessageListeners<'b> {
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this type to make the impl signature compatible: `&'b MessageListeners<'b>`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #105572 <https://github.com/rust-lang/rust/issues/105572>
+note: the lint level is defined here
+  --> $DIR/impl-implied-bounds-compatibility.rs:1:9
+   |
+LL | #![deny(implied_bounds_entailment)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+

tests/ui/proc-macro/panic-abort.rs

@@ -0,0 +1,4 @@
+// error-pattern: building proc macro crate with `panic=abort` may crash the compiler should the proc-macro panic
+// compile-flags: --crate-type proc-macro -Cpanic=abort
+// force-host
+// check-pass

tests/ui/proc-macro/panic-abort.stderr

@@ -0,0 +1,4 @@
+warning: building proc macro crate with `panic=abort` may crash the compiler should the proc-macro panic
+
+warning: 1 warning emitted
+

tests/ui/suggestions/issue-105761-suggest-self-for-closure.fixed

@@ -0,0 +1,28 @@
+//run-rustfix
+#![allow(unused)]
+
+struct S;
+impl S {
+    fn foo(&mut self) {
+        let x = |this: &Self, v: i32| {
+            this.bar();
+            this.hel();
+        };
+        self.qux(); //~ ERROR cannot borrow `*self` as mutable because it is also borrowed as immutable
+        x(self, 1);
+        x(self, 3);
+    }
+    fn bar(&self) {}
+    fn hel(&self) {}
+    fn qux(&mut self) {}
+
+    fn hello(&mut self) {
+        let y = |this: &Self| {
+            this.bar();
+        };
+        self.qux(); //~ ERROR cannot borrow `*self` as mutable because it is also borrowed as immutable
+        y(self);
+    }
+}
+
+fn main() {}

tests/ui/suggestions/issue-105761-suggest-self-for-closure.rs

@@ -0,0 +1,28 @@
+//run-rustfix
+#![allow(unused)]
+
+struct S;
+impl S {
+    fn foo(&mut self) {
+        let x = |v: i32| {
+            self.bar();
+            self.hel();
+        };
+        self.qux(); //~ ERROR cannot borrow `*self` as mutable because it is also borrowed as immutable
+        x(1);
+        x(3);
+    }
+    fn bar(&self) {}
+    fn hel(&self) {}
+    fn qux(&mut self) {}
+
+    fn hello(&mut self) {
+        let y = || {
+            self.bar();
+        };
+        self.qux(); //~ ERROR cannot borrow `*self` as mutable because it is also borrowed as immutable
+        y();
+    }
+}
+
+fn main() {}

tests/ui/suggestions/issue-105761-suggest-self-for-closure.stderr

@@ -0,0 +1,49 @@
+error[E0502]: cannot borrow `*self` as mutable because it is also borrowed as immutable
+  --> $DIR/issue-105761-suggest-self-for-closure.rs:11:9
+   |
+LL |         let x = |v: i32| {
+   |                 -------- immutable borrow occurs here
+LL |             self.bar();
+   |             ---- first borrow occurs due to use of `self` in closure
+...
+LL |         self.qux();
+   |         ^^^^^^^^^^ mutable borrow occurs here
+LL |         x(1);
+   |         - immutable borrow later used here
+   |
+help: try explicitly pass `&Self` into the Closure as an argument
+   |
+LL ~         let x = |this: &Self, v: i32| {
+LL ~             this.bar();
+LL ~             this.hel();
+LL |         };
+LL |         self.qux();
+LL ~         x(self, 1);
+LL ~         x(self, 3);
+   |
+
+error[E0502]: cannot borrow `*self` as mutable because it is also borrowed as immutable
+  --> $DIR/issue-105761-suggest-self-for-closure.rs:23:9
+   |
+LL |         let y = || {
+   |                 -- immutable borrow occurs here
+LL |             self.bar();
+   |             ---- first borrow occurs due to use of `self` in closure
+LL |         };
+LL |         self.qux();
+   |         ^^^^^^^^^^ mutable borrow occurs here
+LL |         y();
+   |         - immutable borrow later used here
+   |
+help: try explicitly pass `&Self` into the Closure as an argument
+   |
+LL ~         let y = |this: &Self| {
+LL ~             this.bar();
+LL |         };
+LL |         self.qux();
+LL ~         y(self);
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0502`.