diff --git a/compiler/rustc_attr_data_structures/src/attributes.rs b/compiler/rustc_attr_data_structures/src/attributes.rs
index b656db3252823..f61efcf238852 100644
--- a/compiler/rustc_attr_data_structures/src/attributes.rs
+++ b/compiler/rustc_attr_data_structures/src/attributes.rs
@@ -198,6 +198,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_allow_const_fn_unstable]`.
     AllowConstFnUnstable(ThinVec<Symbol>, Span),
 
+    /// Represents `#[rustc_allow_incoherent_impl]`.
+    AllowIncoherentImpl(Span),
+
     /// Represents `#[allow_internal_unstable]`.
     AllowInternalUnstable(ThinVec<(Symbol, Span)>, Span),
 
@@ -211,6 +214,12 @@ pub enum AttributeKind {
         span: Span,
     },
 
+    /// Represents `#[rustc_coherence_is_core]`.
+    CoherenceIsCore,
+
+    /// Represents `#[rustc_coinductive]`.
+    Coinductive(Span),
+
     /// Represents `#[cold]`.
     Cold(Span),
 
@@ -234,9 +243,18 @@ pub enum AttributeKind {
     /// Represents `#[rustc_const_stable_indirect]`.
     ConstStabilityIndirect,
 
+    /// Represents `#[const_trait]`.
+    ConstTrait(Span),
+
+    ///Represents `#[rustc_deny_explicit_impl]`.
+    DenyExplicitImpl(Span),
+
     /// Represents [`#[deprecated]`](https://doc.rust-lang.org/stable/reference/attributes/diagnostics.html#the-deprecated-attribute).
     Deprecation { deprecation: Deprecation, span: Span },
 
+    /// Represents `#[rustc_do_not_implement_via_object]`.
+    DoNotImplementViaObject(Span),
+
     /// Represents [`#[doc]`](https://doc.rust-lang.org/stable/rustdoc/write-documentation/the-doc-attribute.html).
     DocComment { style: AttrStyle, kind: CommentKind, span: Span, comment: Symbol },
 
@@ -260,6 +278,9 @@ pub enum AttributeKind {
     /// Represents `#[ffi_pure]`.
     FfiPure(Span),
 
+    /// Represents `#[fundamental]`.
+    Fundamental,
+
     /// Represents `#[ignore]`
     Ignore {
         span: Span,
@@ -282,6 +303,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_macro_transparency]`.
     MacroTransparency(Transparency),
 
+    /// Represents `#[marker]`.
+    Marker(Span),
+
     /// Represents [`#[may_dangle]`](https://std-dev-guide.rust-lang.org/tricky/may-dangle.html).
     MayDangle(Span),
 
@@ -307,6 +331,9 @@ pub enum AttributeKind {
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),
 
+    /// Represents `#[rustc_paren_sugar]`.
+    ParenSugar(Span),
+
     /// Represents `#[rustc_pass_by_value]` (used by the `rustc_pass_by_value` lint).
     PassByValue(Span),
 
@@ -331,6 +358,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_skip_during_method_dispatch]`.
     SkipDuringMethodDispatch { array: bool, boxed_slice: bool, span: Span },
 
+    /// Represents `#[rustc_specialization_trait]`.
+    SpecializationTrait(Span),
+
     /// Represents `#[stable]`, `#[unstable]` and `#[rustc_allowed_through_unstable_modules]`.
     Stability {
         stability: Stability,
@@ -347,6 +377,12 @@ pub enum AttributeKind {
     /// Represents `#[track_caller]`
     TrackCaller(Span),
 
+    /// Represents `#[type_const]`.
+    TypeConst(Span),
+
+    /// Represents `#[rustc_unsafe_specialization_marker]`.
+    UnsafeSpecializationMarker(Span),
+
     /// Represents `#[used]`
     Used { used_by: UsedBy, span: Span },
     // tidy-alphabetical-end
diff --git a/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs b/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs
index 5414c7b103bcb..ad587523e0373 100644
--- a/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs
+++ b/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs
@@ -15,27 +15,35 @@ impl AttributeKind {
             // tidy-alphabetical-start
             Align { .. } => No,
             AllowConstFnUnstable(..) => No,
+            AllowIncoherentImpl(..) => No,
             AllowInternalUnstable(..) => Yes,
             AsPtr(..) => Yes,
             BodyStability { .. } => No,
+            CoherenceIsCore => No,
+            Coinductive(..) => No,
             Cold(..) => No,
             Confusables { .. } => Yes,
             ConstContinue(..) => No,
             ConstStability { .. } => Yes,
             ConstStabilityIndirect => No,
+            ConstTrait(..) => No,
+            DenyExplicitImpl(..) => No,
             Deprecation { .. } => Yes,
+            DoNotImplementViaObject(..) => No,
             DocComment { .. } => Yes,
             Dummy => No,
             ExportName { .. } => Yes,
             ExportStable => No,
             FfiConst(..) => No,
             FfiPure(..) => No,
+            Fundamental { .. } => Yes,
             Ignore { .. } => No,
             Inline(..) => No,
             LinkName { .. } => Yes,
             LinkSection { .. } => No,
             LoopMatch(..) => No,
             MacroTransparency(..) => Yes,
+            Marker(..) => No,
             MayDangle(..) => No,
             MustUse { .. } => Yes,
             Naked(..) => No,
@@ -43,6 +51,7 @@ impl AttributeKind {
             NoMangle(..) => No,
             NonExhaustive(..) => Yes,
             Optimize(..) => No,
+            ParenSugar(..) => No,
             PassByValue(..) => Yes,
             Path(..) => No,
             PubTransparent(..) => Yes,
@@ -51,10 +60,13 @@ impl AttributeKind {
             RustcLayoutScalarValidRangeStart(..) => Yes,
             RustcObjectLifetimeDefault => No,
             SkipDuringMethodDispatch { .. } => No,
+            SpecializationTrait(..) => No,
             Stability { .. } => Yes,
             StdInternalSymbol(..) => No,
             TargetFeature(..) => No,
             TrackCaller(..) => Yes,
+            TypeConst(..) => Yes,
+            UnsafeSpecializationMarker(..) => No,
             Used { .. } => No,
             // tidy-alphabetical-end
         }
diff --git a/compiler/rustc_attr_parsing/src/attributes/traits.rs b/compiler/rustc_attr_parsing/src/attributes/traits.rs
index c29dbf4d1e9e2..ee8a33ae9c43d 100644
--- a/compiler/rustc_attr_parsing/src/attributes/traits.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/traits.rs
@@ -2,14 +2,15 @@ use core::mem;
 
 use rustc_attr_data_structures::AttributeKind;
 use rustc_feature::{AttributeTemplate, template};
-use rustc_span::{Symbol, sym};
+use rustc_span::{Span, Symbol, sym};
 
-use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::attributes::{
+    AttributeOrder, NoArgsAttributeParser, OnDuplicate, SingleAttributeParser,
+};
 use crate::context::{AcceptContext, Stage};
 use crate::parser::ArgParser;
 
 pub(crate) struct SkipDuringMethodDispatchParser;
-
 impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
     const PATH: &[Symbol] = &[sym::rustc_skip_during_method_dispatch];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
@@ -52,3 +53,95 @@ impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
         Some(AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span: cx.attr_span })
     }
 }
+
+pub(crate) struct ParenSugarParser;
+impl<S: Stage> NoArgsAttributeParser<S> for ParenSugarParser {
+    const PATH: &[Symbol] = &[sym::rustc_paren_sugar];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::ParenSugar;
+}
+
+pub(crate) struct TypeConstParser;
+impl<S: Stage> NoArgsAttributeParser<S> for TypeConstParser {
+    const PATH: &[Symbol] = &[sym::type_const];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::TypeConst;
+}
+
+// Markers
+
+pub(crate) struct MarkerParser;
+impl<S: Stage> NoArgsAttributeParser<S> for MarkerParser {
+    const PATH: &[Symbol] = &[sym::marker];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::Marker;
+}
+
+pub(crate) struct DenyExplicitImplParser;
+impl<S: Stage> NoArgsAttributeParser<S> for DenyExplicitImplParser {
+    const PATH: &[Symbol] = &[sym::rustc_deny_explicit_impl];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DenyExplicitImpl;
+}
+
+pub(crate) struct DoNotImplementViaObjectParser;
+impl<S: Stage> NoArgsAttributeParser<S> for DoNotImplementViaObjectParser {
+    const PATH: &[Symbol] = &[sym::rustc_do_not_implement_via_object];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::DoNotImplementViaObject;
+}
+
+// Const traits
+
+pub(crate) struct ConstTraitParser;
+impl<S: Stage> NoArgsAttributeParser<S> for ConstTraitParser {
+    const PATH: &[Symbol] = &[sym::const_trait];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::ConstTrait;
+}
+
+// Specialization
+
+pub(crate) struct SpecializationTraitParser;
+impl<S: Stage> NoArgsAttributeParser<S> for SpecializationTraitParser {
+    const PATH: &[Symbol] = &[sym::rustc_specialization_trait];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::SpecializationTrait;
+}
+
+pub(crate) struct UnsafeSpecializationMarkerParser;
+impl<S: Stage> NoArgsAttributeParser<S> for UnsafeSpecializationMarkerParser {
+    const PATH: &[Symbol] = &[sym::rustc_unsafe_specialization_marker];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::UnsafeSpecializationMarker;
+}
+
+// Coherence
+
+pub(crate) struct CoinductiveParser;
+impl<S: Stage> NoArgsAttributeParser<S> for CoinductiveParser {
+    const PATH: &[Symbol] = &[sym::rustc_coinductive];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::Coinductive;
+}
+
+pub(crate) struct AllowIncoherentImplParser;
+impl<S: Stage> NoArgsAttributeParser<S> for AllowIncoherentImplParser {
+    const PATH: &[Symbol] = &[sym::rustc_allow_incoherent_impl];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::AllowIncoherentImpl;
+}
+
+pub(crate) struct CoherenceIsCoreParser;
+impl<S: Stage> NoArgsAttributeParser<S> for CoherenceIsCoreParser {
+    const PATH: &[Symbol] = &[sym::rustc_coherence_is_core];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::CoherenceIsCore;
+}
+
+pub(crate) struct FundamentalParser;
+impl<S: Stage> NoArgsAttributeParser<S> for FundamentalParser {
+    const PATH: &[Symbol] = &[sym::fundamental];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::Fundamental;
+}
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index dbe1a5b2ad03d..cc10bb3098a61 100644
--- a/compiler/rustc_attr_parsing/src/context.rs
+++ b/compiler/rustc_attr_parsing/src/context.rs
@@ -43,7 +43,12 @@ use crate::attributes::stability::{
     BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
 };
 use crate::attributes::test_attrs::IgnoreParser;
-use crate::attributes::traits::SkipDuringMethodDispatchParser;
+use crate::attributes::traits::{
+    AllowIncoherentImplParser, CoherenceIsCoreParser, CoinductiveParser, ConstTraitParser,
+    DenyExplicitImplParser, DoNotImplementViaObjectParser, FundamentalParser, MarkerParser,
+    ParenSugarParser, SkipDuringMethodDispatchParser, SpecializationTraitParser, TypeConstParser,
+    UnsafeSpecializationMarkerParser,
+};
 use crate::attributes::transparency::TransparencyParser;
 use crate::attributes::{AttributeParser as _, Combine, Single, WithoutArgs};
 use crate::parser::{ArgParser, MetaItemParser, PathParser};
@@ -146,22 +151,34 @@ attribute_parsers!(
         Single<RustcObjectLifetimeDefaultParser>,
         Single<SkipDuringMethodDispatchParser>,
         Single<TransparencyParser>,
+        Single<WithoutArgs<AllowIncoherentImplParser>>,
         Single<WithoutArgs<AsPtrParser>>,
+        Single<WithoutArgs<CoherenceIsCoreParser>>,
+        Single<WithoutArgs<CoinductiveParser>>,
         Single<WithoutArgs<ColdParser>>,
         Single<WithoutArgs<ConstContinueParser>>,
         Single<WithoutArgs<ConstStabilityIndirectParser>>,
+        Single<WithoutArgs<ConstTraitParser>>,
+        Single<WithoutArgs<DenyExplicitImplParser>>,
+        Single<WithoutArgs<DoNotImplementViaObjectParser>>,
         Single<WithoutArgs<ExportStableParser>>,
         Single<WithoutArgs<FfiConstParser>>,
         Single<WithoutArgs<FfiPureParser>>,
+        Single<WithoutArgs<FundamentalParser>>,
         Single<WithoutArgs<LoopMatchParser>>,
+        Single<WithoutArgs<MarkerParser>>,
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,
         Single<WithoutArgs<NoMangleParser>>,
         Single<WithoutArgs<NonExhaustiveParser>>,
+        Single<WithoutArgs<ParenSugarParser>>,
         Single<WithoutArgs<PassByValueParser>>,
         Single<WithoutArgs<PubTransparentParser>>,
+        Single<WithoutArgs<SpecializationTraitParser>>,
         Single<WithoutArgs<StdInternalSymbolParser>>,
         Single<WithoutArgs<TrackCallerParser>>,
+        Single<WithoutArgs<TypeConstParser>>,
+        Single<WithoutArgs<UnsafeSpecializationMarkerParser>>,
         // tidy-alphabetical-end
     ];
 );
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 9c62244f3c9ff..74418adc43c1d 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -680,7 +680,7 @@ pub(crate) fn run_pass_manager(
             if attributes::has_string_attr(function, enzyme_marker) {
                 // Sanity check: Ensure 'noinline' is present before replacing it.
                 assert!(
-                    !attributes::has_attr(function, Function, llvm::AttributeKind::NoInline),
+                    attributes::has_attr(function, Function, llvm::AttributeKind::NoInline),
                     "Expected __enzyme function to have 'noinline' before adding 'alwaysinline'"
                 );
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs
index 1f266514f346f..bb53a8b5d28b4 100644
--- a/compiler/rustc_codegen_ssa/src/traits/builder.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs
@@ -554,12 +554,33 @@ pub trait BuilderMethods<'a, 'tcx>:
     /// Called for `StorageDead`
     fn lifetime_end(&mut self, ptr: Self::Value, size: Size);
 
+    /// "Finally codegen the call"
+    ///
+    /// ## Arguments
+    ///
+    /// The `fn_attrs`, `fn_abi`, and `instance` arguments are Options because they are advisory.
+    /// They relate to optional codegen enhancements like LLVM CFI, and do not affect ABI per se.
+    /// Any ABI-related transformations should be handled by different, earlier stages of codegen.
+    /// For instance, in the caller of `BuilderMethods::call`.
+    ///
+    /// This means that a codegen backend which disregards `fn_attrs`, `fn_abi`, and `instance`
+    /// should still do correct codegen, and code should not be miscompiled if they are omitted.
+    /// It is not a miscompilation in this sense if it fails to run under CFI, other sanitizers, or
+    /// in the context of other compiler-enhanced security features.
+    ///
+    /// The typical case that they are None is during the codegen of intrinsics and lang-items,
+    /// as those are "fake functions" with only a trivial ABI if any, et cetera.
+    ///
+    /// ## Return
+    ///
+    /// Must return the value the function will return so it can be written to the destination,
+    /// assuming the function does not explicitly pass the destination as a pointer in `args`.
     fn call(
         &mut self,
         llty: Self::Type,
         fn_attrs: Option<&CodegenFnAttrs>,
         fn_abi: Option<&FnAbi<'tcx, Ty<'tcx>>>,
-        llfn: Self::Value,
+        fn_val: Self::Value,
         args: &[Self::Value],
         funclet: Option<&Self::Funclet>,
         instance: Option<Instance<'tcx>>,
diff --git a/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs b/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
index 7d0c6be4c650d..c5ecf43046c74 100644
--- a/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/intrinsic.rs
@@ -6,16 +6,22 @@ use crate::mir::operand::OperandRef;
 use crate::mir::place::PlaceRef;
 
 pub trait IntrinsicCallBuilderMethods<'tcx>: BackendTypes {
+    /// Higher-level interface to emitting calls to intrinsics
+    ///
     /// Remember to add all intrinsics here, in `compiler/rustc_hir_analysis/src/check/mod.rs`,
     /// and in `library/core/src/intrinsics.rs`; if you need access to any LLVM intrinsics,
     /// add them to `compiler/rustc_codegen_llvm/src/context.rs`.
     /// Returns `Err` if another instance should be called instead. This is used to invoke
     /// intrinsic default bodies in case an intrinsic is not implemented by the backend.
+    ///
+    /// NOTE: allowed to call [`BuilderMethods::call`]
+    ///
+    /// [`BuilderMethods::call`]: super::builder::BuilderMethods::call
     fn codegen_intrinsic_call(
         &mut self,
         instance: ty::Instance<'tcx>,
         args: &[OperandRef<'tcx, Self::Value>],
-        result: PlaceRef<'tcx, Self::Value>,
+        result_dest: PlaceRef<'tcx, Self::Value>,
         span: Span,
     ) -> Result<(), ty::Instance<'tcx>>;
 
diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
index bd25b4a326086..80bf13dc4b7a3 100644
--- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
@@ -7,6 +7,7 @@
 //! `tcx.inherent_impls(def_id)`). That value, however,
 //! is computed by selecting an idea from this table.
 
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -85,7 +86,10 @@ impl<'tcx> InherentCollect<'tcx> {
             }
 
             for &impl_item in items {
-                if !self.tcx.has_attr(impl_item, sym::rustc_allow_incoherent_impl) {
+                if !find_attr!(
+                    self.tcx.get_all_attrs(impl_item),
+                    AttributeKind::AllowIncoherentImpl(_)
+                ) {
                     let impl_span = self.tcx.def_span(impl_def_id);
                     return Err(self.tcx.dcx().emit_err(errors::InherentTyOutsideRelevant {
                         span: impl_span,
@@ -116,7 +120,10 @@ impl<'tcx> InherentCollect<'tcx> {
         if !self.tcx.hir_rustc_coherence_is_core() {
             if self.tcx.features().rustc_attrs() {
                 for &impl_item in items {
-                    if !self.tcx.has_attr(impl_item, sym::rustc_allow_incoherent_impl) {
+                    if !find_attr!(
+                        self.tcx.get_all_attrs(impl_item),
+                        AttributeKind::AllowIncoherentImpl(_)
+                    ) {
                         let span = self.tcx.def_span(impl_def_id);
                         return Err(self.tcx.dcx().emit_err(errors::InherentTyOutsidePrimitive {
                             span,
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index a185291887dc7..431d99a572d26 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -852,39 +852,41 @@ fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef {
         _ => span_bug!(item.span, "trait_def_of_item invoked on non-trait"),
     };
 
+    let attrs = tcx.get_all_attrs(def_id);
     // Only regular traits can be const.
-    let constness = if !is_alias && tcx.has_attr(def_id, sym::const_trait) {
+    let constness = if !is_alias && find_attr!(attrs, AttributeKind::ConstTrait(_)) {
         hir::Constness::Const
     } else {
         hir::Constness::NotConst
     };
 
-    let paren_sugar = tcx.has_attr(def_id, sym::rustc_paren_sugar);
+    let paren_sugar = find_attr!(attrs, AttributeKind::ParenSugar(_));
     if paren_sugar && !tcx.features().unboxed_closures() {
         tcx.dcx().emit_err(errors::ParenSugarAttribute { span: item.span });
     }
 
     // Only regular traits can be marker.
-    let is_marker = !is_alias && tcx.has_attr(def_id, sym::marker);
+    let is_marker = !is_alias && find_attr!(attrs, AttributeKind::Marker(_));
 
-    let rustc_coinductive = tcx.has_attr(def_id, sym::rustc_coinductive);
-    let is_fundamental = tcx.has_attr(def_id, sym::fundamental);
+    let rustc_coinductive = find_attr!(attrs, AttributeKind::Coinductive(_));
+    let is_fundamental = find_attr!(attrs, AttributeKind::Fundamental);
 
     let [skip_array_during_method_dispatch, skip_boxed_slice_during_method_dispatch] = find_attr!(
-        tcx.get_all_attrs(def_id),
-        AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span:_ } => [*array, *boxed_slice]
+        attrs,
+        AttributeKind::SkipDuringMethodDispatch { array, boxed_slice, span: _ } => [*array, *boxed_slice]
     )
     .unwrap_or([false; 2]);
 
-    let specialization_kind = if tcx.has_attr(def_id, sym::rustc_unsafe_specialization_marker) {
+    let specialization_kind = if find_attr!(attrs, AttributeKind::UnsafeSpecializationMarker(_)) {
         ty::trait_def::TraitSpecializationKind::Marker
-    } else if tcx.has_attr(def_id, sym::rustc_specialization_trait) {
+    } else if find_attr!(attrs, AttributeKind::SpecializationTrait(_)) {
         ty::trait_def::TraitSpecializationKind::AlwaysApplicable
     } else {
         ty::trait_def::TraitSpecializationKind::None
     };
-    let must_implement_one_of = tcx
-        .get_attr(def_id, sym::rustc_must_implement_one_of)
+    let must_implement_one_of = attrs
+        .iter()
+        .find(|attr| attr.has_name(sym::rustc_must_implement_one_of))
         // Check that there are at least 2 arguments of `#[rustc_must_implement_one_of]`
         // and that they are all identifiers
         .and_then(|attr| match attr.meta_item_list() {
@@ -958,8 +960,8 @@ fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef {
             no_dups.then_some(list)
         });
 
-    let deny_explicit_impl = tcx.has_attr(def_id, sym::rustc_deny_explicit_impl);
-    let implement_via_object = !tcx.has_attr(def_id, sym::rustc_do_not_implement_via_object);
+    let deny_explicit_impl = find_attr!(attrs, AttributeKind::DenyExplicitImpl(_));
+    let implement_via_object = !find_attr!(attrs, AttributeKind::DoNotImplementViaObject(_));
 
     ty::TraitDef {
         def_id: def_id.to_def_id(),
diff --git a/compiler/rustc_middle/src/hir/map.rs b/compiler/rustc_middle/src/hir/map.rs
index 291707878a342..84710e5e636e0 100644
--- a/compiler/rustc_middle/src/hir/map.rs
+++ b/compiler/rustc_middle/src/hir/map.rs
@@ -4,6 +4,7 @@
 
 use rustc_abi::ExternAbi;
 use rustc_ast::visit::{VisitorResult, walk_list};
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::svh::Svh;
@@ -15,7 +16,7 @@ use rustc_hir::intravisit::Visitor;
 use rustc_hir::*;
 use rustc_hir_pretty as pprust_hir;
 use rustc_span::def_id::StableCrateId;
-use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol, kw, sym, with_metavar_spans};
+use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol, kw, with_metavar_spans};
 
 use crate::hir::{ModuleItems, nested_filter};
 use crate::middle::debugger_visualizer::DebuggerVisualizerFile;
@@ -369,7 +370,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn hir_rustc_coherence_is_core(self) -> bool {
-        self.hir_krate_attrs().iter().any(|attr| attr.has_name(sym::rustc_coherence_is_core))
+        find_attr!(self.hir_krate_attrs(), AttributeKind::CoherenceIsCore)
     }
 
     pub fn hir_get_module(self, module: LocalModDefId) -> (&'tcx Mod<'tcx>, Span, HirId) {
diff --git a/compiler/rustc_middle/src/mir/basic_blocks.rs b/compiler/rustc_middle/src/mir/basic_blocks.rs
index d0dbf64dc5959..0d2e23609ce35 100644
--- a/compiler/rustc_middle/src/mir/basic_blocks.rs
+++ b/compiler/rustc_middle/src/mir/basic_blocks.rs
@@ -1,6 +1,5 @@
 use std::sync::OnceLock;
 
-use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::graph;
 use rustc_data_structures::graph::dominators::{Dominators, dominators};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -10,7 +9,7 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use smallvec::SmallVec;
 
 use crate::mir::traversal::Postorder;
-use crate::mir::{BasicBlock, BasicBlockData, START_BLOCK, Terminator, TerminatorKind};
+use crate::mir::{BasicBlock, BasicBlockData, START_BLOCK};
 
 #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable, TypeVisitable)]
 pub struct BasicBlocks<'tcx> {
@@ -21,15 +20,6 @@ pub struct BasicBlocks<'tcx> {
 // Typically 95%+ of basic blocks have 4 or fewer predecessors.
 type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
 
-/// Each `(target, switch)` entry in the map contains a list of switch values
-/// that lead to a `target` block from a `switch` block.
-///
-/// Note: this type is currently never instantiated, because it's only used for
-/// `BasicBlocks::switch_sources`, which is only called by backwards analyses
-/// that do `SwitchInt` handling, and we don't have any of those, not even in
-/// tests. See #95120 and #94576.
-type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[SwitchTargetValue; 1]>>;
-
 #[derive(Debug, Clone, Copy)]
 pub enum SwitchTargetValue {
     // A normal switch value.
@@ -41,7 +31,6 @@ pub enum SwitchTargetValue {
 #[derive(Clone, Default, Debug)]
 struct Cache {
     predecessors: OnceLock<Predecessors>,
-    switch_sources: OnceLock<SwitchSources>,
     reverse_postorder: OnceLock<Vec<BasicBlock>>,
     dominators: OnceLock<Dominators<BasicBlock>>,
 }
@@ -86,33 +75,6 @@ impl<'tcx> BasicBlocks<'tcx> {
         })
     }
 
-    /// Returns info about switch values that lead from one block to another
-    /// block. See `SwitchSources`.
-    #[inline]
-    pub fn switch_sources(&self) -> &SwitchSources {
-        self.cache.switch_sources.get_or_init(|| {
-            let mut switch_sources: SwitchSources = FxHashMap::default();
-            for (bb, data) in self.basic_blocks.iter_enumerated() {
-                if let Some(Terminator {
-                    kind: TerminatorKind::SwitchInt { targets, .. }, ..
-                }) = &data.terminator
-                {
-                    for (value, target) in targets.iter() {
-                        switch_sources
-                            .entry((target, bb))
-                            .or_default()
-                            .push(SwitchTargetValue::Normal(value));
-                    }
-                    switch_sources
-                        .entry((targets.otherwise(), bb))
-                        .or_default()
-                        .push(SwitchTargetValue::Otherwise);
-                }
-            }
-            switch_sources
-        })
-    }
-
     /// Returns mutable reference to basic blocks. Invalidates CFG cache.
     #[inline]
     pub fn as_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
diff --git a/compiler/rustc_middle/src/ty/adt.rs b/compiler/rustc_middle/src/ty/adt.rs
index 44165b06f1c33..275458fc85f8d 100644
--- a/compiler/rustc_middle/src/ty/adt.rs
+++ b/compiler/rustc_middle/src/ty/adt.rs
@@ -17,7 +17,6 @@ use rustc_index::{IndexSlice, IndexVec};
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use rustc_query_system::ich::StableHashingContext;
 use rustc_session::DataTypeKind;
-use rustc_span::sym;
 use rustc_type_ir::solve::AdtDestructorKind;
 use tracing::{debug, info, trace};
 
@@ -296,7 +295,7 @@ impl AdtDefData {
             flags |= AdtFlags::HAS_CTOR;
         }
 
-        if tcx.has_attr(did, sym::fundamental) {
+        if find_attr!(tcx.get_all_attrs(did), AttributeKind::Fundamental) {
             flags |= AdtFlags::IS_FUNDAMENTAL;
         }
         if tcx.is_lang_item(did, LangItem::PhantomData) {
diff --git a/compiler/rustc_middle/src/ty/assoc.rs b/compiler/rustc_middle/src/ty/assoc.rs
index 78b2e265b488c..344a81f5e24d1 100644
--- a/compiler/rustc_middle/src/ty/assoc.rs
+++ b/compiler/rustc_middle/src/ty/assoc.rs
@@ -1,9 +1,10 @@
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace};
 use rustc_hir::def_id::DefId;
 use rustc_macros::{Decodable, Encodable, HashStable};
-use rustc_span::{Ident, Symbol, sym};
+use rustc_span::{Ident, Symbol};
 
 use super::{TyCtxt, Visibility};
 use crate::ty;
@@ -160,7 +161,7 @@ impl AssocItem {
             // Inherent impl but this attr is only applied to trait assoc items.
             (AssocItemContainer::Impl, None) => return true,
         };
-        tcx.has_attr(def_id, sym::type_const)
+        find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_))
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/instance.rs b/compiler/rustc_middle/src/ty/instance.rs
index 21b7500e46fe0..d5767ca3786e8 100644
--- a/compiler/rustc_middle/src/ty/instance.rs
+++ b/compiler/rustc_middle/src/ty/instance.rs
@@ -991,18 +991,16 @@ fn needs_fn_once_adapter_shim(
             Ok(false)
         }
         (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => {
-            // The closure fn `llfn` is a `fn(&self, ...)`. We want a
-            // `fn(&mut self, ...)`. In fact, at codegen time, these are
-            // basically the same thing, so we can just return llfn.
+            // The closure fn is a `fn(&self, ...)`, but we want a `fn(&mut self, ...)`.
+            // At codegen time, these are basically the same, so we can just return the closure.
             Ok(false)
         }
         (ty::ClosureKind::Fn | ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => {
-            // The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut
-            // self, ...)`. We want a `fn(self, ...)`. We can produce
-            // this by doing something like:
+            // The closure fn is a `fn(&self, ...)` or `fn(&mut self, ...)`, but
+            // we want a `fn(self, ...)`. We can produce this by doing something like:
             //
-            //     fn call_once(self, ...) { call_mut(&self, ...) }
-            //     fn call_once(mut self, ...) { call_mut(&mut self, ...) }
+            //     fn call_once(self, ...) { Fn::call(&self, ...) }
+            //     fn call_once(mut self, ...) { FnMut::call_mut(&mut self, ...) }
             //
             // These are both the same at codegen time.
             Ok(true)
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index b780b1c5776bc..0177a95498bcd 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -1782,21 +1782,18 @@ impl<'tcx> TyCtxt<'tcx> {
         did: impl Into<DefId>,
         attr: Symbol,
     ) -> impl Iterator<Item = &'tcx hir::Attribute> {
-        self.get_all_attrs(did).filter(move |a: &&hir::Attribute| a.has_name(attr))
+        self.get_all_attrs(did).iter().filter(move |a: &&hir::Attribute| a.has_name(attr))
     }
 
     /// Gets all attributes.
     ///
     /// To see if an item has a specific attribute, you should use [`rustc_attr_data_structures::find_attr!`] so you can use matching.
-    pub fn get_all_attrs(
-        self,
-        did: impl Into<DefId>,
-    ) -> impl Iterator<Item = &'tcx hir::Attribute> {
+    pub fn get_all_attrs(self, did: impl Into<DefId>) -> &'tcx [hir::Attribute] {
         let did: DefId = did.into();
         if let Some(did) = did.as_local() {
-            self.hir_attrs(self.local_def_id_to_hir_id(did)).iter()
+            self.hir_attrs(self.local_def_id_to_hir_id(did))
         } else {
-            self.attrs_for_def(did).iter()
+            self.attrs_for_def(did)
         }
     }
 
diff --git a/compiler/rustc_mir_dataflow/src/framework/direction.rs b/compiler/rustc_mir_dataflow/src/framework/direction.rs
index cb647476db8f3..79c0db7d72831 100644
--- a/compiler/rustc_mir_dataflow/src/framework/direction.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/direction.rs
@@ -1,5 +1,6 @@
 use std::ops::RangeInclusive;
 
+use rustc_middle::bug;
 use rustc_middle::mir::{
     self, BasicBlock, CallReturnPlaces, Location, SwitchTargetValue, TerminatorEdges,
 };
@@ -112,15 +113,11 @@ impl Direction for Backward {
                     propagate(pred, &tmp);
                 }
 
-                mir::TerminatorKind::SwitchInt { ref targets, ref discr } => {
-                    if let Some(mut data) = analysis.get_switch_int_data(block, discr) {
-                        let mut tmp = analysis.bottom_value(body);
-                        for &value in &body.basic_blocks.switch_sources()[&(block, pred)] {
-                            tmp.clone_from(exit_state);
-                            analysis
-                                .apply_switch_int_edge_effect(&mut data, &mut tmp, value, targets);
-                            propagate(pred, &tmp);
-                        }
+                mir::TerminatorKind::SwitchInt { ref discr, .. } => {
+                    if let Some(_data) = analysis.get_switch_int_data(pred, discr) {
+                        bug!(
+                            "SwitchInt edge effects are unsupported in backward dataflow analyses"
+                        );
                     } else {
                         propagate(pred, exit_state)
                     }
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
index 11424ec3724bf..bb5c1e0e653a7 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_parse/src/validate_attr.rs
@@ -283,6 +283,18 @@ pub fn check_builtin_meta_item(
                 | sym::rustc_confusables
                 | sym::rustc_skip_during_method_dispatch
                 | sym::rustc_pass_by_value
+                | sym::rustc_deny_explicit_impl
+                | sym::rustc_do_not_implement_via_object
+                | sym::rustc_coinductive
+                | sym::const_trait
+                | sym::rustc_specialization_trait
+                | sym::rustc_unsafe_specialization_marker
+                | sym::rustc_allow_incoherent_impl
+                | sym::rustc_coherence_is_core
+                | sym::marker
+                | sym::fundamental
+                | sym::rustc_paren_sugar
+                | sym::type_const
                 | sym::repr
                 | sym::align
                 | sym::deprecated
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 0aa6a2b41cfb6..2c95fead9e801 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -120,12 +120,35 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         for attr in attrs {
             let mut style = None;
             match attr {
-                Attribute::Parsed(AttributeKind::SkipDuringMethodDispatch {
-                    span: attr_span,
-                    ..
-                }) => {
+                Attribute::Parsed(
+                    AttributeKind::SkipDuringMethodDispatch { span: attr_span, .. }
+                    | AttributeKind::Coinductive(attr_span)
+                    | AttributeKind::ConstTrait(attr_span)
+                    | AttributeKind::DenyExplicitImpl(attr_span)
+                    | AttributeKind::DoNotImplementViaObject(attr_span),
+                ) => {
                     self.check_must_be_applied_to_trait(*attr_span, span, target);
                 }
+                &Attribute::Parsed(
+                    AttributeKind::SpecializationTrait(attr_span)
+                    | AttributeKind::UnsafeSpecializationMarker(attr_span)
+                    | AttributeKind::ParenSugar(attr_span),
+                ) => {
+                    // FIXME: more validation is needed
+                    self.check_must_be_applied_to_trait(attr_span, span, target);
+                }
+                &Attribute::Parsed(AttributeKind::TypeConst(attr_span)) => {
+                    self.check_type_const(hir_id, attr_span, target)
+                }
+                &Attribute::Parsed(AttributeKind::Marker(attr_span)) => {
+                    self.check_marker(hir_id, attr_span, span, target)
+                }
+                Attribute::Parsed(AttributeKind::Fundamental | AttributeKind::CoherenceIsCore) => {
+                    // FIXME: add validation
+                }
+                &Attribute::Parsed(AttributeKind::AllowIncoherentImpl(attr_span)) => {
+                    self.check_allow_incoherent_impl(attr_span, span, target)
+                }
                 Attribute::Parsed(AttributeKind::Confusables { first_span, .. }) => {
                     self.check_confusables(*first_span, target);
                 }
@@ -259,7 +282,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::no_sanitize, ..] => {
                             self.check_no_sanitize(attr, span, target)
                         }
-                        [sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
                         [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
                         [sym::doc, ..] => self.check_doc_attrs(
                             attr,
@@ -297,16 +319,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         | [sym::rustc_dirty, ..]
                         | [sym::rustc_if_this_changed, ..]
                         | [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
-                        [sym::rustc_coinductive, ..]
-                        | [sym::rustc_must_implement_one_of, ..]
-                        | [sym::rustc_deny_explicit_impl, ..]
-                        | [sym::rustc_do_not_implement_via_object, ..]
-                        | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr.span(), span, target),
+                        [sym::rustc_must_implement_one_of, ..] => self.check_must_be_applied_to_trait(attr.span(), span, target),
                         [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
                         [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
-                        [sym::rustc_allow_incoherent_impl, ..] => {
-                            self.check_allow_incoherent_impl(attr, span, target)
-                        }
                         [sym::rustc_has_incoherent_inherent_impls, ..] => {
                             self.check_has_incoherent_inherent_impls(attr, span, target)
                         }
@@ -339,9 +354,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::coroutine, ..] => {
                             self.check_coroutine(attr, target);
                         }
-                        [sym::type_const, ..] => {
-                            self.check_type_const(hir_id,attr, target);
-                        }
                         [sym::linkage, ..] => self.check_linkage(attr, span, target),
                         [
                             // ok
@@ -366,7 +378,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::prelude_import
                             | sym::panic_handler
                             | sym::allow_internal_unsafe
-                            | sym::fundamental
                             | sym::lang
                             | sym::needs_allocator
                             | sym::default_lib_allocator
@@ -830,7 +841,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     /// Checks if the `#[marker]` attribute on an `item` is valid.
-    fn check_marker(&self, hir_id: HirId, attr: &Attribute, span: Span, target: Target) {
+    fn check_marker(&self, hir_id: HirId, attr_span: Span, span: Span, target: Target) {
         match target {
             Target::Trait => {}
             // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
@@ -838,13 +849,11 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             // erroneously allowed it and some crates used it accidentally, to be compatible
             // with crates depending on them, we can't throw an error here.
             Target::Field | Target::Arm | Target::MacroDef => {
-                self.inline_attr_str_error_with_macro_def(hir_id, attr.span(), "marker");
+                self.inline_attr_str_error_with_macro_def(hir_id, attr_span, "marker");
             }
             _ => {
-                self.dcx().emit_err(errors::AttrShouldBeAppliedToTrait {
-                    attr_span: attr.span(),
-                    defn_span: span,
-                });
+                self.dcx()
+                    .emit_err(errors::AttrShouldBeAppliedToTrait { attr_span, defn_span: span });
             }
         }
     }
@@ -1489,11 +1498,11 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_allow_incoherent_impl(&self, attr: &Attribute, span: Span, target: Target) {
+    fn check_allow_incoherent_impl(&self, attr_span: Span, span: Span, target: Target) {
         match target {
             Target::Method(MethodKind::Inherent) => {}
             _ => {
-                self.dcx().emit_err(errors::AllowIncoherentImpl { attr_span: attr.span(), span });
+                self.dcx().emit_err(errors::AllowIncoherentImpl { attr_span, span });
             }
         }
     }
@@ -2514,7 +2523,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_type_const(&self, hir_id: HirId, attr: &Attribute, target: Target) {
+    fn check_type_const(&self, hir_id: HirId, attr_span: Span, target: Target) {
         let tcx = self.tcx;
         if target == Target::AssocConst
             && let parent = tcx.parent(hir_id.expect_owner().to_def_id())
@@ -2524,7 +2533,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         } else {
             self.dcx()
                 .struct_span_err(
-                    attr.span(),
+                    attr_span,
                     "`#[type_const]` must only be applied to trait associated constants",
                 )
                 .emit();
diff --git a/library/std/src/sys_common/mod.rs b/library/std/src/sys_common/mod.rs
index b7f4656fa3701..cce88d936b71b 100644
--- a/library/std/src/sys_common/mod.rs
+++ b/library/std/src/sys_common/mod.rs
@@ -11,7 +11,7 @@
 //! This is because `sys_common` not only contains platform-independent code,
 //! but also code that is shared between the different platforms in `sys`.
 //! Ideally all that shared code should be moved to `sys::common`,
-//! and the dependencies between `std`, `sys_common` and `sys` all would form a dag.
+//! and the dependencies between `std`, `sys_common` and `sys` all would form a DAG.
 //! Progress on this is tracked in #84187.
 
 #![allow(missing_docs)]
diff --git a/src/build_helper/src/ci.rs b/src/build_helper/src/ci.rs
index 9d114c70a671b..b5e70eb84cc6c 100644
--- a/src/build_helper/src/ci.rs
+++ b/src/build_helper/src/ci.rs
@@ -9,7 +9,7 @@ pub enum CiEnv {
 impl CiEnv {
     /// Obtains the current CI environment.
     pub fn current() -> CiEnv {
-        if std::env::var("GITHUB_ACTIONS").map_or(false, |e| e == "true") {
+        if std::env::var("GITHUB_ACTIONS").is_ok_and(|e| e == "true") {
             CiEnv::GitHubActions
         } else {
             CiEnv::None
diff --git a/src/build_helper/src/git.rs b/src/build_helper/src/git.rs
index 9d1195aadf848..cbefb836c0044 100644
--- a/src/build_helper/src/git.rs
+++ b/src/build_helper/src/git.rs
@@ -13,7 +13,7 @@ pub struct GitConfig<'a> {
 pub fn output_result(cmd: &mut Command) -> Result<String, String> {
     let output = match cmd.stderr(Stdio::inherit()).output() {
         Ok(status) => status,
-        Err(e) => return Err(format!("failed to run command: {:?}: {}", cmd, e)),
+        Err(e) => return Err(format!("failed to run command: {cmd:?}: {e}")),
     };
     if !output.status.success() {
         return Err(format!(
@@ -62,22 +62,22 @@ pub enum PathFreshness {
 /// The function behaves differently in CI and outside CI.
 ///
 /// - Outside CI, we want to find out if `target_paths` were modified in some local commit on
-/// top of the latest upstream commit that is available in local git history.
-/// If not, we try to find the most recent upstream commit (which we assume are commits
-/// made by bors) that modified `target_paths`.
-/// We don't want to simply take the latest master commit to avoid changing the output of
-/// this function frequently after rebasing on the latest master branch even if `target_paths`
-/// were not modified upstream in the meantime. In that case we would be redownloading CI
-/// artifacts unnecessarily.
+///   top of the latest upstream commit that is available in local git history.
+///   If not, we try to find the most recent upstream commit (which we assume are commits
+///   made by bors) that modified `target_paths`.
+///   We don't want to simply take the latest master commit to avoid changing the output of
+///   this function frequently after rebasing on the latest master branch even if `target_paths`
+///   were not modified upstream in the meantime. In that case we would be redownloading CI
+///   artifacts unnecessarily.
 ///
 /// - In CI, we use a shallow clone of depth 2, i.e., we fetch only a single parent commit
-/// (which will be the most recent bors merge commit) and do not have access
-/// to the full git history. Luckily, we only need to distinguish between two situations:
-/// 1) The current PR made modifications to `target_paths`.
-/// In that case, a build is typically necessary.
-/// 2) The current PR did not make modifications to `target_paths`.
-/// In that case we simply take the latest upstream commit, because on CI there is no need to avoid
-/// redownloading.
+///   (which will be the most recent bors merge commit) and do not have access
+///   to the full git history. Luckily, we only need to distinguish between two situations:
+///   1) The current PR made modifications to `target_paths`.
+///      In that case, a build is typically necessary.
+///   2) The current PR did not make modifications to `target_paths`.
+///      In that case we simply take the latest upstream commit, because on CI there is no need to avoid
+///      redownloading.
 pub fn check_path_modifications(
     git_dir: &Path,
     config: &GitConfig<'_>,
@@ -232,7 +232,7 @@ pub fn get_closest_upstream_commit(
         "--author-date-order",
         &format!("--author={}", config.git_merge_commit_email),
         "-n1",
-        &base,
+        base,
     ]);
 
     let output = output_result(&mut git)?.trim().to_owned();
diff --git a/src/build_helper/src/metrics.rs b/src/build_helper/src/metrics.rs
index 8b82e62a32770..07157e364158d 100644
--- a/src/build_helper/src/metrics.rs
+++ b/src/build_helper/src/metrics.rs
@@ -141,7 +141,7 @@ impl BuildStep {
                 } => {
                     let full_name = format!("{parent_name}-{kind}");
                     let children: Vec<_> =
-                        children.into_iter().filter_map(|s| parse(s, &full_name)).collect();
+                        children.iter().filter_map(|s| parse(s, &full_name)).collect();
                     let children_duration = children.iter().map(|c| c.duration).sum::<Duration>();
                     Some(BuildStep {
                         r#type: kind.to_string(),
diff --git a/src/build_helper/src/util.rs b/src/build_helper/src/util.rs
index 80dd6813d136e..a8355f774e9d1 100644
--- a/src/build_helper/src/util.rs
+++ b/src/build_helper/src/util.rs
@@ -18,29 +18,28 @@ macro_rules! exit {
 pub fn detail_exit(code: i32, is_test: bool) -> ! {
     // if in test and code is an error code, panic with status code provided
     if is_test {
-        panic!("status code: {}", code);
+        panic!("status code: {code}");
     } else {
-        // otherwise,exit with provided status code
+        // otherwise, exit with provided status code
         std::process::exit(code);
     }
 }
 
 pub fn fail(s: &str) -> ! {
-    eprintln!("\n\n{}\n\n", s);
+    eprintln!("\n\n{s}\n\n");
     detail_exit(1, cfg!(test));
 }
 
 pub fn try_run(cmd: &mut Command, print_cmd_on_fail: bool) -> Result<(), ()> {
     let status = match cmd.status() {
         Ok(status) => status,
-        Err(e) => fail(&format!("failed to execute command: {:?}\nerror: {}", cmd, e)),
+        Err(e) => fail(&format!("failed to execute command: {cmd:?}\nerror: {e}")),
     };
     if !status.success() {
         if print_cmd_on_fail {
             println!(
-                "\n\ncommand did not execute successfully: {:?}\n\
-                 expected success, got: {}\n\n",
-                cmd, status
+                "\n\ncommand did not execute successfully: {cmd:?}\n\
+                 expected success, got: {status}\n\n"
             );
         }
         Err(())
@@ -60,7 +59,7 @@ pub fn parse_gitmodules(target_dir: &Path) -> Vec<String> {
     for line in BufReader::new(file).lines().map_while(Result::ok) {
         let line = line.trim();
         if line.starts_with("path") {
-            let actual_path = line.split(' ').last().expect("Couldn't get value of path");
+            let actual_path = line.split(' ').next_back().expect("Couldn't get value of path");
             submodules_paths.push(actual_path.to_owned());
         }
     }
diff --git a/src/doc/rustc/src/SUMMARY.md b/src/doc/rustc/src/SUMMARY.md
index e1742631f63cc..7c688e32bc0dd 100644
--- a/src/doc/rustc/src/SUMMARY.md
+++ b/src/doc/rustc/src/SUMMARY.md
@@ -46,6 +46,7 @@
     - [\*-apple-watchos](platform-support/apple-watchos.md)
     - [\*-apple-visionos](platform-support/apple-visionos.md)
     - [aarch64-nintendo-switch-freestanding](platform-support/aarch64-nintendo-switch-freestanding.md)
+    - [aarch64-unknown-linux-musl](platform-support/aarch64-unknown-linux-musl.md)
     - [amdgcn-amd-amdhsa](platform-support/amdgcn-amd-amdhsa.md)
     - [armeb-unknown-linux-gnueabi](platform-support/armeb-unknown-linux-gnueabi.md)
     - [arm-none-eabi](platform-support/arm-none-eabi.md)
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index ed01de4c1c300..65b7063015388 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -90,7 +90,7 @@ target | notes
 -------|-------
 [`aarch64-pc-windows-gnullvm`](platform-support/windows-gnullvm.md) | ARM64 MinGW (Windows 10+), LLVM ABI
 [`aarch64-pc-windows-msvc`](platform-support/windows-msvc.md) | ARM64 Windows MSVC
-`aarch64-unknown-linux-musl` | ARM64 Linux with musl 1.2.3
+[`aarch64-unknown-linux-musl`](platform-support/aarch64-unknown-linux-musl.md) | ARM64 Linux with musl 1.2.3
 [`aarch64-unknown-linux-ohos`](platform-support/openharmony.md) | ARM64 OpenHarmony
 `arm-unknown-linux-gnueabi` | Armv6 Linux (kernel 3.2+, glibc 2.17)
 `arm-unknown-linux-gnueabihf` | Armv6 Linux, hardfloat (kernel 3.2+, glibc 2.17)
diff --git a/src/doc/rustc/src/platform-support/aarch64-unknown-linux-musl.md b/src/doc/rustc/src/platform-support/aarch64-unknown-linux-musl.md
new file mode 100644
index 0000000000000..5d9a552e4603f
--- /dev/null
+++ b/src/doc/rustc/src/platform-support/aarch64-unknown-linux-musl.md
@@ -0,0 +1,49 @@
+# aarch64-unknown-linux-musl
+
+**Tier: 2**
+
+Target for 64-bit little endian ARMv8-A Linux programs using musl libc.
+
+## Target maintainers
+
+[@Gelbpunkt](https://github.com/Gelbpunkt)
+[@famfo](https://github.com/famfo)
+
+## Requirements
+
+Building the target itself requires a 64-bit little endian ARMv8-A compiler
+that is supported by `cc-rs`.
+
+## Building the target
+
+The target can be built by enabling it for a `rustc` build.
+
+```toml
+[build]
+target = ["aarch64-unknown-linux-musl"]
+```
+
+Make sure your C compiler is included in `$PATH`, then add it to the
+`bootstrap.toml`:
+
+```toml
+[target.aarch64-unknown-linux-musl]
+cc = "aarch64-linux-musl-gcc"
+cxx = "aarch64-linux-musl-g++"
+ar = "aarch64-linux-musl-ar"
+linker = "aarch64-linux-musl-gcc"
+```
+
+## Building Rust programs
+
+This target is distributed through `rustup`, and otherwise requires no
+special configuration.
+
+## Cross-compilation
+
+This target can be cross-compiled from any host.
+
+## Testing
+
+This target can be tested as normal with `x.py` on a 64-bit little endian
+ARMv8-A host or via QEMU emulation.
diff --git a/src/tools/x/Cargo.toml b/src/tools/x/Cargo.toml
index 84a42ca36ef1c..c59f5ff52a0f5 100644
--- a/src/tools/x/Cargo.toml
+++ b/src/tools/x/Cargo.toml
@@ -2,5 +2,5 @@
 name = "x"
 version = "0.1.1"
 description = "Run x.py slightly more conveniently"
-edition = "2021"
+edition = "2024"
 publish = false
diff --git a/src/tools/x/src/main.rs b/src/tools/x/src/main.rs
index b288cfcd5be9c..93167141d34dd 100644
--- a/src/tools/x/src/main.rs
+++ b/src/tools/x/src/main.rs
@@ -19,15 +19,14 @@ const PYTHON2: &str = "python2";
 const PYTHON3: &str = "python3";
 
 fn python() -> &'static str {
-    let val = match env::var_os("PATH") {
-        Some(val) => val,
-        None => return PYTHON,
+    let Some(path) = env::var_os("PATH") else {
+        return PYTHON;
     };
 
     let mut python2 = false;
     let mut python3 = false;
 
-    for dir in env::split_paths(&val) {
+    for dir in env::split_paths(&path) {
         // `python` should always take precedence over python2 / python3 if it exists
         if dir.join(PYTHON).with_extension(EXE_EXTENSION).exists() {
             return PYTHON;
@@ -89,7 +88,7 @@ fn exec_or_status(command: &mut Command) -> io::Result<ExitStatus> {
 fn handle_result(result: io::Result<ExitStatus>, cmd: Command) {
     match result {
         Err(error) => {
-            eprintln!("Failed to invoke `{:?}`: {}", cmd, error);
+            eprintln!("Failed to invoke `{cmd:?}`: {error}");
         }
         Ok(status) => {
             process::exit(status.code().unwrap_or(1));
@@ -98,14 +97,12 @@ fn handle_result(result: io::Result<ExitStatus>, cmd: Command) {
 }
 
 fn main() {
-    match env::args().skip(1).next().as_deref() {
-        Some("--wrapper-version") => {
-            let version = env!("CARGO_PKG_VERSION");
-            println!("{}", version);
-            return;
-        }
-        _ => {}
+    if env::args().nth(1).is_some_and(|s| s == "--wrapper-version") {
+        let version = env!("CARGO_PKG_VERSION");
+        println!("{version}");
+        return;
     }
+
     let current = match env::current_dir() {
         Ok(dir) => dir,
         Err(err) => {
@@ -113,7 +110,6 @@ fn main() {
             process::exit(1);
         }
     };
-
     for dir in current.ancestors() {
         let candidate = dir.join("x.py");
         if candidate.exists() {
diff --git a/tests/rustdoc-json/attrs/target_feature.rs b/tests/rustdoc-json/attrs/target_feature.rs
index 80262d8e33257..5c8aeb84ee3cc 100644
--- a/tests/rustdoc-json/attrs/target_feature.rs
+++ b/tests/rustdoc-json/attrs/target_feature.rs
@@ -6,17 +6,17 @@
 pub fn test1() {}
 
 //@ is "$.index[?(@.name=='test2')].attrs" '["#[target_feature(enable=\"avx\", enable=\"avx2\")]"]'
-//@ is "$.index[?(@.name=='test1')].inner.function.header.is_unsafe" false
+//@ is "$.index[?(@.name=='test2')].inner.function.header.is_unsafe" false
 #[target_feature(enable = "avx,avx2")]
 pub fn test2() {}
 
 //@ is "$.index[?(@.name=='test3')].attrs" '["#[target_feature(enable=\"avx\", enable=\"avx2\")]"]'
-//@ is "$.index[?(@.name=='test1')].inner.function.header.is_unsafe" false
+//@ is "$.index[?(@.name=='test3')].inner.function.header.is_unsafe" false
 #[target_feature(enable = "avx", enable = "avx2")]
 pub fn test3() {}
 
 //@ is "$.index[?(@.name=='test4')].attrs" '["#[target_feature(enable=\"avx\", enable=\"avx2\", enable=\"avx512f\")]"]'
-//@ is "$.index[?(@.name=='test1')].inner.function.header.is_unsafe" false
+//@ is "$.index[?(@.name=='test4')].inner.function.header.is_unsafe" false
 #[target_feature(enable = "avx", enable = "avx2,avx512f")]
 pub fn test4() {}
 
diff --git a/tests/ui/attributes/malformed-attrs.stderr b/tests/ui/attributes/malformed-attrs.stderr
index 5bcb0c4dc0a4c..be529df3a4953 100644
--- a/tests/ui/attributes/malformed-attrs.stderr
+++ b/tests/ui/attributes/malformed-attrs.stderr
@@ -116,24 +116,6 @@ error: malformed `cfi_encoding` attribute input
 LL | #[cfi_encoding]
    | ^^^^^^^^^^^^^^^ help: must be of the form: `#[cfi_encoding = "encoding"]`
 
-error: malformed `type_const` attribute input
-  --> $DIR/malformed-attrs.rs:143:5
-   |
-LL |     #[type_const = 1]
-   |     ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[type_const]`
-
-error: malformed `marker` attribute input
-  --> $DIR/malformed-attrs.rs:155:1
-   |
-LL | #[marker = 3]
-   | ^^^^^^^^^^^^^ help: must be of the form: `#[marker]`
-
-error: malformed `fundamental` attribute input
-  --> $DIR/malformed-attrs.rs:157:1
-   |
-LL | #[fundamental()]
-   | ^^^^^^^^^^^^^^^^ help: must be of the form: `#[fundamental]`
-
 error: malformed `link_ordinal` attribute input
   --> $DIR/malformed-attrs.rs:167:5
    |
@@ -528,6 +510,24 @@ LL | #[rustc_layout_scalar_valid_range_end]
    | expected this to be a list
    | help: must be of the form: `#[rustc_layout_scalar_valid_range_end(end)]`
 
+error[E0565]: malformed `marker` attribute input
+  --> $DIR/malformed-attrs.rs:155:1
+   |
+LL | #[marker = 3]
+   | ^^^^^^^^^---^
+   | |        |
+   | |        didn't expect any arguments here
+   | help: must be of the form: `#[marker]`
+
+error[E0565]: malformed `fundamental` attribute input
+  --> $DIR/malformed-attrs.rs:157:1
+   |
+LL | #[fundamental()]
+   | ^^^^^^^^^^^^^--^
+   | |            |
+   | |            didn't expect any arguments here
+   | help: must be of the form: `#[fundamental]`
+
 error[E0565]: malformed `ffi_pure` attribute input
   --> $DIR/malformed-attrs.rs:165:5
    |
@@ -555,6 +555,15 @@ LL | #[non_exhaustive = 1]
    | |                didn't expect any arguments here
    | help: must be of the form: `#[non_exhaustive]`
 
+error[E0565]: malformed `type_const` attribute input
+  --> $DIR/malformed-attrs.rs:143:5
+   |
+LL |     #[type_const = 1]
+   |     ^^^^^^^^^^^^^---^
+   |     |            |
+   |     |            didn't expect any arguments here
+   |     help: must be of the form: `#[type_const]`
+
 error: attribute should be applied to `const fn`
   --> $DIR/malformed-attrs.rs:34:1
    |
diff --git a/tests/ui/const-generics/mgca/bad-type_const-syntax.stderr b/tests/ui/const-generics/mgca/bad-type_const-syntax.stderr
index 579aff849d6e6..125c778ef1cd3 100644
--- a/tests/ui/const-generics/mgca/bad-type_const-syntax.stderr
+++ b/tests/ui/const-generics/mgca/bad-type_const-syntax.stderr
@@ -1,9 +1,3 @@
-error: malformed `type_const` attribute input
-  --> $DIR/bad-type_const-syntax.rs:2:5
-   |
-LL |     #[type_const()]
-   |     ^^^^^^^^^^^^^^^ help: must be of the form: `#[type_const]`
-
 error[E0658]: the `#[type_const]` attribute is an experimental feature
   --> $DIR/bad-type_const-syntax.rs:2:5
    |
@@ -24,6 +18,15 @@ LL |     #[type_const]
    = help: add `#![feature(min_generic_const_args)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
+error[E0565]: malformed `type_const` attribute input
+  --> $DIR/bad-type_const-syntax.rs:2:5
+   |
+LL |     #[type_const()]
+   |     ^^^^^^^^^^^^--^
+   |     |           |
+   |     |           didn't expect any arguments here
+   |     help: must be of the form: `#[type_const]`
+
 error: `#[type_const]` must only be applied to trait associated constants
   --> $DIR/bad-type_const-syntax.rs:11:5
    |
@@ -32,4 +35,5 @@ LL |     #[type_const]
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+Some errors have detailed explanations: E0565, E0658.
+For more information about an error, try `rustc --explain E0565`.
diff --git a/tests/ui/marker_trait_attr/marker-attribute-with-values.stderr b/tests/ui/marker_trait_attr/marker-attribute-with-values.stderr
index 6f9c9508e7e55..9a2e5add37b35 100644
--- a/tests/ui/marker_trait_attr/marker-attribute-with-values.stderr
+++ b/tests/ui/marker_trait_attr/marker-attribute-with-values.stderr
@@ -1,20 +1,30 @@
-error: malformed `marker` attribute input
+error[E0565]: malformed `marker` attribute input
   --> $DIR/marker-attribute-with-values.rs:3:1
    |
 LL | #[marker(always)]
-   | ^^^^^^^^^^^^^^^^^ help: must be of the form: `#[marker]`
+   | ^^^^^^^^--------^
+   | |       |
+   | |       didn't expect any arguments here
+   | help: must be of the form: `#[marker]`
 
-error: malformed `marker` attribute input
+error[E0565]: malformed `marker` attribute input
   --> $DIR/marker-attribute-with-values.rs:6:1
    |
 LL | #[marker("never")]
-   | ^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[marker]`
+   | ^^^^^^^^---------^
+   | |       |
+   | |       didn't expect any arguments here
+   | help: must be of the form: `#[marker]`
 
-error: malformed `marker` attribute input
+error[E0565]: malformed `marker` attribute input
   --> $DIR/marker-attribute-with-values.rs:9:1
    |
 LL | #[marker(key = "value")]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[marker]`
+   | ^^^^^^^^---------------^
+   | |       |
+   | |       didn't expect any arguments here
+   | help: must be of the form: `#[marker]`
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0565`.