Merge from rustc

.mailmap

@@ -429,6 +429,8 @@ Nilstrieb <48135649+Nilstrieb@users.noreply.github.com> nils <48135649+Nilstrieb
 Nif Ward <nif.ward@gmail.com>
 Nika Layzell <nika@thelayzells.com> <michael@thelayzells.com>
 NODA Kai <nodakai@gmail.com>
+Oğuz Ağcayazı <oguz.agcayazi@gmail.com> <oguz.agcayazi@gmail.com>
+Oğuz Ağcayazı <oguz.agcayazi@gmail.com> <ouz.agz@gmail.com>
 oliver <16816606+o752d@users.noreply.github.com>
 Oliver Middleton <olliemail27@gmail.com> <ollie27@users.noreply.github.com>
 Oliver Scherer <oli-obk@users.noreply.github.com> <git-spam-no-reply9815368754983@oli-obk.de>

Cargo.lock

@@ -6030,19 +6030,21 @@ dependencies = [
 
 [[package]]
 name = "windows-bindgen"
-version = "0.49.0"
+version = "0.51.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6935fb09b84ee57929ae92518b475f5dfdfbeb87c5334756acc28ee8e202b60"
+checksum = "bc1f16b778125675feee0d15d6dd9f6af0e3ac52b3233d63a10aa39230c1cd75"
 dependencies = [
+ "proc-macro2",
+ "rayon",
+ "syn 2.0.29",
  "windows-metadata",
- "windows-tokens",
 ]
 
 [[package]]
 name = "windows-metadata"
-version = "0.49.0"
+version = "0.51.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2f5bca94a32bf1e6a376522b6601275a3b611ee885ec0f1b6a05f17e8cfd3385"
+checksum = "753135d996f9da437c0b31dbde3032489a61708361929bcc07d4fba0b161000e"
 
 [[package]]
 name = "windows-sys"
@@ -6092,12 +6094,6 @@ dependencies = [
  "windows_x86_64_msvc 0.48.0",
 ]
 
-[[package]]
-name = "windows-tokens"
-version = "0.48.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b34c9a3b28cb41db7385546f7f9a8179348dffc89923dde66857b1ba5312f6b4"
-
 [[package]]
 name = "windows_aarch64_gnullvm"
 version = "0.42.2"

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -245,7 +245,7 @@ fn suggest_static_lifetime_for_gat_from_hrtb(
             let Trait(PolyTraitRef { trait_ref, span: trait_span, .. }, _) = bound else { return; };
             diag.span_note(
                 *trait_span,
-                format!("due to current limitations in the borrow checker, this implies a `'static` lifetime")
+                "due to current limitations in the borrow checker, this implies a `'static` lifetime"
             );
             let Some(generics_fn) = hir.get_generics(self.body.source.def_id().expect_local()) else { return; };
             let Def(_, trait_res_defid) = trait_ref.path.res else { return; };
@@ -277,7 +277,7 @@ fn suggest_static_lifetime_for_gat_from_hrtb(
         if suggestions.len() > 0 {
             suggestions.dedup();
             diag.multipart_suggestion_verbose(
-                format!("consider restricting the type parameter to the `'static` lifetime"),
+                "consider restricting the type parameter to the `'static` lifetime",
                 suggestions,
                 Applicability::MaybeIncorrect,
             );

compiler/rustc_codegen_cranelift/src/base.rs

@@ -875,7 +875,7 @@ pub(crate) fn codegen_place<'tcx>(
             PlaceElem::Deref => {
                 cplace = cplace.place_deref(fx);
             }
-            PlaceElem::OpaqueCast(ty) => cplace = cplace.place_opaque_cast(fx, ty),
+            PlaceElem::OpaqueCast(ty) => bug!("encountered OpaqueCast({ty}) in codegen"),
             PlaceElem::Field(field, _ty) => {
                 cplace = cplace.place_field(fx, field);
             }

compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs

@@ -21,7 +21,7 @@ fn report_simd_type_validation_error(
 pub(super) fn codegen_simd_intrinsic_call<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
     intrinsic: Symbol,
-    _args: GenericArgsRef<'tcx>,
+    generic_args: GenericArgsRef<'tcx>,
     args: &[mir::Operand<'tcx>],
     ret: CPlace<'tcx>,
     target: BasicBlock,
@@ -117,6 +117,54 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
             });
         }
 
+        // simd_shuffle_generic<T, U, const I: &[u32]>(x: T, y: T) -> U
+        sym::simd_shuffle_generic => {
+            let [x, y] = args else {
+                bug!("wrong number of args for intrinsic {intrinsic}");
+            };
+            let x = codegen_operand(fx, x);
+            let y = codegen_operand(fx, y);
+
+            if !x.layout().ty.is_simd() {
+                report_simd_type_validation_error(fx, intrinsic, span, x.layout().ty);
+                return;
+            }
+
+            let idx = generic_args[2]
+                .expect_const()
+                .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(span))
+                .unwrap()
+                .unwrap_branch();
+
+            assert_eq!(x.layout(), y.layout());
+            let layout = x.layout();
+
+            let (lane_count, lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
+            let (ret_lane_count, ret_lane_ty) = ret.layout().ty.simd_size_and_type(fx.tcx);
+
+            assert_eq!(lane_ty, ret_lane_ty);
+            assert_eq!(idx.len() as u64, ret_lane_count);
+
+            let total_len = lane_count * 2;
+
+            let indexes =
+                idx.iter().map(|idx| idx.unwrap_leaf().try_to_u16().unwrap()).collect::<Vec<u16>>();
+
+            for &idx in &indexes {
+                assert!(u64::from(idx) < total_len, "idx {} out of range 0..{}", idx, total_len);
+            }
+
+            for (out_idx, in_idx) in indexes.into_iter().enumerate() {
+                let in_lane = if u64::from(in_idx) < lane_count {
+                    x.value_lane(fx, in_idx.into())
+                } else {
+                    y.value_lane(fx, u64::from(in_idx) - lane_count)
+                };
+                let out_lane = ret.place_lane(fx, u64::try_from(out_idx).unwrap());
+                out_lane.write_cvalue(fx, in_lane);
+            }
+        }
+
         // simd_shuffle<T, I, U>(x: T, y: T, idx: I) -> U
         sym::simd_shuffle => {
             let (x, y, idx) = match args {

compiler/rustc_codegen_cranelift/src/value_and_place.rs

@@ -674,14 +674,6 @@ fn transmute_scalar<'tcx>(
         }
     }
 
-    pub(crate) fn place_opaque_cast(
-        self,
-        fx: &mut FunctionCx<'_, '_, 'tcx>,
-        ty: Ty<'tcx>,
-    ) -> CPlace<'tcx> {
-        CPlace { inner: self.inner, layout: fx.layout_of(ty) }
-    }
-
     pub(crate) fn place_field(
         self,
         fx: &mut FunctionCx<'_, '_, 'tcx>,

compiler/rustc_codegen_llvm/messages.ftl

@@ -37,6 +37,8 @@ codegen_llvm_lto_disallowed = lto can only be run for executables, cdylibs and s
 
 codegen_llvm_lto_dylib = lto cannot be used for `dylib` crate type without `-Zdylib-lto`
 
+codegen_llvm_lto_proc_macro = lto cannot be used for `proc-macro` crate type without `-Zdylib-lto`
+
 codegen_llvm_missing_features =
     add the missing features in a `target_feature` attribute
 

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -2,7 +2,7 @@
     self, bitcode_section_name, save_temp_bitcode, CodegenDiagnosticsStage, DiagnosticHandlers,
 };
 use crate::errors::{
-    DynamicLinkingWithLTO, LlvmError, LtoBitcodeFromRlib, LtoDisallowed, LtoDylib,
+    DynamicLinkingWithLTO, LlvmError, LtoBitcodeFromRlib, LtoDisallowed, LtoDylib, LtoProcMacro,
 };
 use crate::llvm::{self, build_string};
 use crate::{LlvmCodegenBackend, ModuleLlvm};
@@ -36,8 +36,12 @@
 
 pub fn crate_type_allows_lto(crate_type: CrateType) -> bool {
     match crate_type {
-        CrateType::Executable | CrateType::Dylib | CrateType::Staticlib | CrateType::Cdylib => true,
-        CrateType::Rlib | CrateType::ProcMacro => false,
+        CrateType::Executable
+        | CrateType::Dylib
+        | CrateType::Staticlib
+        | CrateType::Cdylib
+        | CrateType::ProcMacro => true,
+        CrateType::Rlib => false,
     }
 }
 
@@ -87,6 +91,11 @@ fn prepare_lto(
                     diag_handler.emit_err(LtoDylib);
                     return Err(FatalError);
                 }
+            } else if *crate_type == CrateType::ProcMacro {
+                if !cgcx.opts.unstable_opts.dylib_lto {
+                    diag_handler.emit_err(LtoProcMacro);
+                    return Err(FatalError);
+                }
             }
         }
 

compiler/rustc_codegen_llvm/src/errors.rs

@@ -138,6 +138,10 @@ fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaran
 #[diag(codegen_llvm_lto_dylib)]
 pub(crate) struct LtoDylib;
 
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_lto_proc_macro)]
+pub(crate) struct LtoProcMacro;
+
 #[derive(Diagnostic)]
 #[diag(codegen_llvm_lto_bitcode_from_rlib)]
 pub(crate) struct LtoBitcodeFromRlib {

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -15,7 +15,7 @@
 use rustc_codegen_ssa::traits::*;
 use rustc_hir as hir;
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf};
-use rustc_middle::ty::{self, Ty};
+use rustc_middle::ty::{self, GenericArgsRef, Ty};
 use rustc_middle::{bug, span_bug};
 use rustc_span::{sym, symbol::kw, Span, Symbol};
 use rustc_target::abi::{self, Align, HasDataLayout, Primitive};
@@ -376,7 +376,9 @@ fn codegen_intrinsic_call(
             }
 
             _ if name.as_str().starts_with("simd_") => {
-                match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
+                match generic_simd_intrinsic(
+                    self, name, callee_ty, fn_args, args, ret_ty, llret_ty, span,
+                ) {
                     Ok(llval) => llval,
                     Err(()) => return,
                 }
@@ -911,6 +913,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
     bx: &mut Builder<'_, 'll, 'tcx>,
     name: Symbol,
     callee_ty: Ty<'tcx>,
+    fn_args: GenericArgsRef<'tcx>,
     args: &[OperandRef<'tcx, &'ll Value>],
     ret_ty: Ty<'tcx>,
     llret_ty: &'ll Type,
@@ -1030,6 +1033,56 @@ macro_rules! require_simd {
         ));
     }
 
+    if name == sym::simd_shuffle_generic {
+        let idx = fn_args[2]
+            .expect_const()
+            .eval(tcx, ty::ParamEnv::reveal_all(), Some(span))
+            .unwrap()
+            .unwrap_branch();
+        let n = idx.len() as u64;
+
+        require_simd!(ret_ty, InvalidMonomorphization::SimdReturn { span, name, ty: ret_ty });
+        let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            out_len == n,
+            InvalidMonomorphization::ReturnLength { span, name, in_len: n, ret_ty, out_len }
+        );
+        require!(
+            in_elem == out_ty,
+            InvalidMonomorphization::ReturnElement { span, name, in_elem, in_ty, ret_ty, out_ty }
+        );
+
+        let total_len = in_len * 2;
+
+        let indices: Option<Vec<_>> = idx
+            .iter()
+            .enumerate()
+            .map(|(arg_idx, val)| {
+                let idx = val.unwrap_leaf().try_to_i32().unwrap();
+                if idx >= i32::try_from(total_len).unwrap() {
+                    bx.sess().emit_err(InvalidMonomorphization::ShuffleIndexOutOfBounds {
+                        span,
+                        name,
+                        arg_idx: arg_idx as u64,
+                        total_len: total_len.into(),
+                    });
+                    None
+                } else {
+                    Some(bx.const_i32(idx))
+                }
+            })
+            .collect();
+        let Some(indices) = indices else {
+            return Ok(bx.const_null(llret_ty));
+        };
+
+        return Ok(bx.shuffle_vector(
+            args[0].immediate(),
+            args[1].immediate(),
+            bx.const_vector(&indices),
+        ));
+    }
+
     if name == sym::simd_shuffle {
         // Make sure this is actually an array, since typeck only checks the length-suffixed
         // version of this intrinsic.

compiler/rustc_codegen_ssa/messages.ftl

@@ -46,8 +46,6 @@ codegen_ssa_ignoring_output = ignoring -o because multiple .{$extension} files w
 codegen_ssa_illegal_link_ordinal_format = illegal ordinal format in `link_ordinal`
     .note = an unsuffixed integer value, e.g., `1`, is expected
 
-codegen_ssa_incompatible_linking_modifiers = link modifiers combination `+bundle,+whole-archive` is unstable when generating rlibs
-
 codegen_ssa_insufficient_vs_code_product = VS Code is a different product, and is not sufficient.
 
 codegen_ssa_invalid_link_ordinal_nargs = incorrect number of arguments to `#[link_ordinal]`

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -365,15 +365,9 @@ fn link_rlib<'a>(
     // loaded from the libraries found here and then encode that into the
     // metadata of the rlib we're generating somehow.
     for lib in codegen_results.crate_info.used_libraries.iter() {
-        let NativeLibKind::Static { bundle: None | Some(true), whole_archive } = lib.kind else {
+        let NativeLibKind::Static { bundle: None | Some(true), .. } = lib.kind else {
             continue;
         };
-        if whole_archive == Some(true)
-            && flavor == RlibFlavor::Normal
-            && !codegen_results.crate_info.feature_packed_bundled_libs
-        {
-            sess.emit_err(errors::IncompatibleLinkingModifiers);
-        }
         if flavor == RlibFlavor::Normal && let Some(filename) = lib.filename {
             let path = find_native_static_library(filename.as_str(), true, &lib_search_paths, sess);
             let src = read(path).map_err(|e| sess.emit_fatal(errors::ReadFileError {message: e }))?;

compiler/rustc_codegen_ssa/src/base.rs

@@ -181,7 +181,7 @@ pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 old_info
             }
         }
-        (_, &ty::Dynamic(ref data, _, _)) => meth::get_vtable(cx, source, data.principal()),
+        (_, ty::Dynamic(data, _, _)) => meth::get_vtable(cx, source, data.principal()),
         _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
     }
 }
@@ -857,7 +857,6 @@ pub fn new(tcx: TyCtxt<'_>, target_cpu: String) -> CrateInfo {
             dependency_formats: tcx.dependency_formats(()).clone(),
             windows_subsystem,
             natvis_debugger_visualizers: Default::default(),
-            feature_packed_bundled_libs: tcx.features().packed_bundled_libs,
         };
         let crates = tcx.crates(());
 

compiler/rustc_codegen_ssa/src/errors.rs

@@ -107,10 +107,6 @@ pub struct CreateTempDir {
     pub error: Error,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_incompatible_linking_modifiers)]
-pub struct IncompatibleLinkingModifiers;
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_add_native_library)]
 pub struct AddNativeLibrary {

compiler/rustc_codegen_ssa/src/lib.rs

@@ -164,7 +164,6 @@ pub struct CrateInfo {
     pub dependency_formats: Lrc<Dependencies>,
     pub windows_subsystem: Option<String>,
     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
-    pub feature_packed_bundled_libs: bool, // unstable feature flag.
 }
 
 #[derive(Encodable, Decodable)]

compiler/rustc_codegen_ssa/src/mir/place.rs

@@ -463,7 +463,9 @@ pub fn codegen_place(
                 mir::ProjectionElem::Field(ref field, _) => {
                     cg_base.project_field(bx, field.index())
                 }
-                mir::ProjectionElem::OpaqueCast(ty) => cg_base.project_type(bx, ty),
+                mir::ProjectionElem::OpaqueCast(ty) => {
+                    bug!("encountered OpaqueCast({ty}) in codegen")
+                }
                 mir::ProjectionElem::Index(index) => {
                     let index = &mir::Operand::Copy(mir::Place::from(index));
                     let index = self.codegen_operand(bx, index);

compiler/rustc_const_eval/src/interpret/projection.rs

@@ -316,7 +316,9 @@ pub fn project<P>(&self, base: &P, proj_elem: mir::PlaceElem<'tcx>) -> InterpRes
     {
         use rustc_middle::mir::ProjectionElem::*;
         Ok(match proj_elem {
-            OpaqueCast(ty) => base.transmute(self.layout_of(ty)?, self)?,
+            OpaqueCast(ty) => {
+                span_bug!(self.cur_span(), "OpaqueCast({ty}) encountered after borrowck")
+            }
             Field(field, _) => self.project_field(base, field.index())?,
             Downcast(_, variant) => self.project_downcast(base, variant)?,
             Deref => self.deref_pointer(&base.to_op(self)?)?.into(),

compiler/rustc_const_eval/src/transform/validate.rs

@@ -633,6 +633,14 @@ fn visit_projection_elem(
         location: Location,
     ) {
         match elem {
+            ProjectionElem::OpaqueCast(ty)
+                if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) =>
+            {
+                self.fail(
+                    location,
+                    format!("explicit opaque type cast to `{ty}` after `RevealAll`"),
+                )
+            }
             ProjectionElem::Index(index) => {
                 let index_ty = self.body.local_decls[index].ty;
                 if index_ty != self.tcx.types.usize {

compiler/rustc_error_codes/src/error_codes/E0760.md

@@ -5,7 +5,7 @@ or `Self` that references lifetimes from a parent scope.
 
 Erroneous code example:
 
-```compile_fail,edition2018
+```ignore,edition2018
 struct S<'a>(&'a i32);
 
 impl<'a> S<'a> {

compiler/rustc_feature/src/accepted.rs

@@ -197,6 +197,8 @@ macro_rules! declare_features {
     /// + `impl<I:Iterator> Iterator for &mut Iterator`
     /// + `impl Debug for Foo<'_>`
     (accepted, impl_header_lifetime_elision, "1.31.0", Some(15872), None),
+    /// Allows referencing `Self` and projections in impl-trait.
+    (accepted, impl_trait_projections, "CURRENT_RUSTC_VERSION", Some(103532), None),
     /// Allows using `a..=b` and `..=b` as inclusive range syntaxes.
     (accepted, inclusive_range_syntax, "1.26.0", Some(28237), None),
     /// Allows inferring outlives requirements (RFC 2093).
@@ -267,6 +269,8 @@ macro_rules! declare_features {
     (accepted, non_modrs_mods, "1.30.0", Some(44660), None),
     /// Allows the use of or-patterns (e.g., `0 | 1`).
     (accepted, or_patterns, "1.53.0", Some(54883), None),
+    /// Allows using `+bundle,+whole-archive` link modifiers with native libs.
+    (accepted, packed_bundled_libs, "CURRENT_RUSTC_VERSION", Some(108081), None),
     /// Allows annotating functions conforming to `fn(&PanicInfo) -> !` with `#[panic_handler]`.
     /// This defines the behavior of panics.
     (accepted, panic_handler, "1.30.0", Some(44489), None),

compiler/rustc_feature/src/active.rs

@@ -241,8 +241,6 @@ pub fn set(&self, features: &mut Features, span: Span) {
     (active, linkage, "1.0.0", Some(29603), None),
     /// Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed.
     (internal, needs_panic_runtime, "1.10.0", Some(32837), None),
-    /// Allows using `+bundled,+whole-archive` native libs.
-    (active, packed_bundled_libs, "1.69.0", Some(108081), None),
     /// Allows using the `#![panic_runtime]` attribute.
     (internal, panic_runtime, "1.10.0", Some(32837), None),
     /// Allows `extern "platform-intrinsic" { ... }`.
@@ -472,8 +470,6 @@ pub fn set(&self, features: &mut Features, span: Span) {
     (active, impl_trait_in_assoc_type, "1.70.0", Some(63063), None),
     /// Allows `impl Trait` as output type in `Fn` traits in return position of functions.
     (active, impl_trait_in_fn_trait_return, "1.64.0", Some(99697), None),
-    /// Allows referencing `Self` and projections in impl-trait.
-    (active, impl_trait_projections, "1.67.0", Some(103532), None),
     /// Allows using imported `main` function
     (active, imported_main, "1.53.0", Some(28937), None),
     /// Allows associated types in inherent impls.

compiler/rustc_hir_analysis/messages.ftl

@@ -38,6 +38,17 @@ hir_analysis_cast_thin_pointer_to_fat_pointer = cannot cast thin pointer `{$expr
 hir_analysis_closure_implicit_hrtb = implicit types in closure signatures are forbidden when `for<...>` is present
     .label = `for<...>` is here
 
+hir_analysis_coerce_unsized_may = the trait `{$trait_name}` may only be implemented for a coercion between structures
+
+hir_analysis_coerce_unsized_multi = implementing the trait `CoerceUnsized` requires multiple coercions
+    .note = `CoerceUnsized` may only be implemented for a coercion between structures with one field being coerced
+    .coercions_note = currently, {$number} fields need coercions: {$coercions}
+    .label = requires multiple coercions
+
+hir_analysis_coercion_between_struct_same_note = expected coercion between the same definition; expected `{$source_path}`, found `{$target_path}`
+
+hir_analysis_coercion_between_struct_single_note = expected a single field to be coerced, none found
+
 hir_analysis_const_bound_for_non_const_trait =
     ~const can only be applied to `#[const_trait]` traits
 
@@ -61,6 +72,15 @@ hir_analysis_copy_impl_on_type_with_dtor =
     the trait `Copy` cannot be implemented for this type; the type has a destructor
     .label = `Copy` not allowed on types with destructors
 
+hir_analysis_dispatch_from_dyn_multi = implementing the `DispatchFromDyn` trait requires multiple coercions
+    .note = the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced
+    .coercions_note = currently, {$number} fields need coercions: {$coercions}
+
+hir_analysis_dispatch_from_dyn_repr = structs implementing `DispatchFromDyn` may not have `#[repr(packed)]` or `#[repr(C)]`
+
+hir_analysis_dispatch_from_dyn_zst = the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment, and nothing else
+    .note = extra field `{$name}` of type `{$ty}` is not allowed
+
 hir_analysis_drop_impl_negative = negative `Drop` impls are not supported
 
 hir_analysis_drop_impl_on_wrong_item =
@@ -232,6 +252,8 @@ hir_analysis_pass_to_variadic_function = can't pass `{$ty}` to variadic function
 hir_analysis_placeholder_not_allowed_item_signatures = the placeholder `_` is not allowed within types on item signatures for {$kind}
     .label = not allowed in type signatures
 
+hir_analysis_requires_note = the `{$trait_name}` impl for `{$ty}` requires that `{$error_predicate}`
+
 hir_analysis_return_type_notation_conflicting_bound =
     ambiguous associated function `{$assoc_name}` for `{$ty_name}`
     .note = `{$assoc_name}` is declared in two supertraits: `{$first_bound}` and `{$second_bound}`
@@ -299,6 +321,9 @@ hir_analysis_too_large_static = extern static is too large for the current archi
 hir_analysis_track_caller_on_main = `main` function is not allowed to be `#[track_caller]`
     .suggestion = remove this annotation
 
+hir_analysis_trait_cannot_impl_for_ty = the trait `{$trait_name}` cannot be implemented for this type
+    .label = this field does not implement `{$trait_name}`
+
 hir_analysis_trait_object_declared_with_no_traits =
     at least one trait is required for an object type
     .alias_span = this alias does not contain a trait

compiler/rustc_hir_analysis/src/check/check.rs

@@ -5,18 +5,15 @@
 use super::compare_impl_item::{compare_impl_method, compare_impl_ty};
 use super::*;
 use rustc_attr as attr;
-use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
-use rustc_hir::def::{CtorKind, DefKind, Res};
+use rustc_hir::def::{CtorKind, DefKind};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
-use rustc_hir::intravisit::Visitor;
-use rustc_hir::{ItemKind, Node, PathSegment};
-use rustc_infer::infer::opaque_types::ConstrainOpaqueTypeRegionVisitor;
+use rustc_hir::Node;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, TraitEngineExt as _};
 use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
-use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::traits::{DefiningAnchor, ObligationCauseCode};
 use rustc_middle::ty::fold::BottomUpFolder;
@@ -218,9 +215,6 @@ fn check_opaque(tcx: TyCtxt<'_>, id: hir::ItemId) {
     let args = GenericArgs::identity_for_item(tcx, item.owner_id);
     let span = tcx.def_span(item.owner_id.def_id);
 
-    if !tcx.features().impl_trait_projections {
-        check_opaque_for_inheriting_lifetimes(tcx, item.owner_id.def_id, span);
-    }
     if tcx.type_of(item.owner_id.def_id).instantiate_identity().references_error() {
         return;
     }
@@ -231,129 +225,6 @@ fn check_opaque(tcx: TyCtxt<'_>, id: hir::ItemId) {
     let _ = check_opaque_meets_bounds(tcx, item.owner_id.def_id, span, &origin);
 }
 
-/// Checks that an opaque type does not use `Self` or `T::Foo` projections that would result
-/// in "inheriting lifetimes".
-#[instrument(level = "debug", skip(tcx, span))]
-pub(super) fn check_opaque_for_inheriting_lifetimes(
-    tcx: TyCtxt<'_>,
-    def_id: LocalDefId,
-    span: Span,
-) {
-    let item = tcx.hir().expect_item(def_id);
-    debug!(?item, ?span);
-
-    struct ProhibitOpaqueVisitor<'tcx> {
-        tcx: TyCtxt<'tcx>,
-        opaque_identity_ty: Ty<'tcx>,
-        parent_count: u32,
-        references_parent_regions: bool,
-        selftys: Vec<(Span, Option<String>)>,
-    }
-
-    impl<'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for ProhibitOpaqueVisitor<'tcx> {
-        type BreakTy = Ty<'tcx>;
-
-        fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-            debug!(?t, "root_visit_ty");
-            if t == self.opaque_identity_ty {
-                ControlFlow::Continue(())
-            } else {
-                t.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
-                    tcx: self.tcx,
-                    op: |region| {
-                        if let ty::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = *region
-                            && index < self.parent_count
-                        {
-                            self.references_parent_regions= true;
-                        }
-                    },
-                });
-                if self.references_parent_regions {
-                    ControlFlow::Break(t)
-                } else {
-                    ControlFlow::Continue(())
-                }
-            }
-        }
-    }
-
-    impl<'tcx> Visitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
-        type NestedFilter = nested_filter::OnlyBodies;
-
-        fn nested_visit_map(&mut self) -> Self::Map {
-            self.tcx.hir()
-        }
-
-        fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) {
-            match arg.kind {
-                hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments {
-                    [PathSegment { res: Res::SelfTyParam { .. }, .. }] => {
-                        let impl_ty_name = None;
-                        self.selftys.push((path.span, impl_ty_name));
-                    }
-                    [PathSegment { res: Res::SelfTyAlias { alias_to: def_id, .. }, .. }] => {
-                        let impl_ty_name = Some(self.tcx.def_path_str(*def_id));
-                        self.selftys.push((path.span, impl_ty_name));
-                    }
-                    _ => {}
-                },
-                _ => {}
-            }
-            hir::intravisit::walk_ty(self, arg);
-        }
-    }
-
-    if let ItemKind::OpaqueTy(&hir::OpaqueTy {
-        origin: hir::OpaqueTyOrigin::AsyncFn(..) | hir::OpaqueTyOrigin::FnReturn(..),
-        ..
-    }) = item.kind
-    {
-        let args = GenericArgs::identity_for_item(tcx, def_id);
-        let opaque_identity_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
-        let mut visitor = ProhibitOpaqueVisitor {
-            opaque_identity_ty,
-            parent_count: tcx.generics_of(def_id).parent_count as u32,
-            references_parent_regions: false,
-            tcx,
-            selftys: vec![],
-        };
-        let prohibit_opaque = tcx
-            .explicit_item_bounds(def_id)
-            .instantiate_identity_iter_copied()
-            .try_for_each(|(predicate, _)| predicate.visit_with(&mut visitor));
-
-        if let Some(ty) = prohibit_opaque.break_value() {
-            visitor.visit_item(&item);
-            let is_async = match item.kind {
-                ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
-                    matches!(origin, hir::OpaqueTyOrigin::AsyncFn(..))
-                }
-                _ => unreachable!(),
-            };
-
-            let mut err = feature_err(
-                &tcx.sess.parse_sess,
-                sym::impl_trait_projections,
-                span,
-                format!(
-                    "`{}` return type cannot contain a projection or `Self` that references \
-                    lifetimes from a parent scope",
-                    if is_async { "async fn" } else { "impl Trait" },
-                ),
-            );
-            for (span, name) in visitor.selftys {
-                err.span_suggestion(
-                    span,
-                    "consider spelling out the type instead",
-                    name.unwrap_or_else(|| format!("{ty:?}")),
-                    Applicability::MaybeIncorrect,
-                );
-            }
-            err.emit();
-        }
-    }
-}
-
 /// Checks that an opaque type does not contain cycles.
 pub(super) fn check_opaque_for_cycles<'tcx>(
     tcx: TyCtxt<'tcx>,

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -20,6 +20,7 @@ fn equate_intrinsic_type<'tcx>(
     it: &hir::ForeignItem<'_>,
     n_tps: usize,
     n_lts: usize,
+    n_cts: usize,
     sig: ty::PolyFnSig<'tcx>,
 ) {
     let (own_counts, span) = match &it.kind {
@@ -51,7 +52,7 @@ fn equate_intrinsic_type<'tcx>(
 
     if gen_count_ok(own_counts.lifetimes, n_lts, "lifetime")
         && gen_count_ok(own_counts.types, n_tps, "type")
-        && gen_count_ok(own_counts.consts, 0, "const")
+        && gen_count_ok(own_counts.consts, n_cts, "const")
     {
         let it_def_id = it.owner_id.def_id;
         check_function_signature(
@@ -489,7 +490,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
     };
     let sig = tcx.mk_fn_sig(inputs, output, false, unsafety, Abi::RustIntrinsic);
     let sig = ty::Binder::bind_with_vars(sig, bound_vars);
-    equate_intrinsic_type(tcx, it, n_tps, n_lts, sig)
+    equate_intrinsic_type(tcx, it, n_tps, n_lts, 0, sig)
 }
 
 /// Type-check `extern "platform-intrinsic" { ... }` functions.
@@ -501,9 +502,9 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
 
     let name = it.ident.name;
 
-    let (n_tps, inputs, output) = match name {
+    let (n_tps, n_cts, inputs, output) = match name {
         sym::simd_eq | sym::simd_ne | sym::simd_lt | sym::simd_le | sym::simd_gt | sym::simd_ge => {
-            (2, vec![param(0), param(0)], param(1))
+            (2, 0, vec![param(0), param(0)], param(1))
         }
         sym::simd_add
         | sym::simd_sub
@@ -519,8 +520,8 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_fmax
         | sym::simd_fpow
         | sym::simd_saturating_add
-        | sym::simd_saturating_sub => (1, vec![param(0), param(0)], param(0)),
-        sym::simd_arith_offset => (2, vec![param(0), param(1)], param(0)),
+        | sym::simd_saturating_sub => (1, 0, vec![param(0), param(0)], param(0)),
+        sym::simd_arith_offset => (2, 0, vec![param(0), param(1)], param(0)),
         sym::simd_neg
         | sym::simd_bswap
         | sym::simd_bitreverse
@@ -538,25 +539,25 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_ceil
         | sym::simd_floor
         | sym::simd_round
-        | sym::simd_trunc => (1, vec![param(0)], param(0)),
-        sym::simd_fpowi => (1, vec![param(0), tcx.types.i32], param(0)),
-        sym::simd_fma => (1, vec![param(0), param(0), param(0)], param(0)),
-        sym::simd_gather => (3, vec![param(0), param(1), param(2)], param(0)),
-        sym::simd_scatter => (3, vec![param(0), param(1), param(2)], Ty::new_unit(tcx)),
-        sym::simd_insert => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
-        sym::simd_extract => (2, vec![param(0), tcx.types.u32], param(1)),
+        | sym::simd_trunc => (1, 0, vec![param(0)], param(0)),
+        sym::simd_fpowi => (1, 0, vec![param(0), tcx.types.i32], param(0)),
+        sym::simd_fma => (1, 0, vec![param(0), param(0), param(0)], param(0)),
+        sym::simd_gather => (3, 0, vec![param(0), param(1), param(2)], param(0)),
+        sym::simd_scatter => (3, 0, vec![param(0), param(1), param(2)], Ty::new_unit(tcx)),
+        sym::simd_insert => (2, 0, vec![param(0), tcx.types.u32, param(1)], param(0)),
+        sym::simd_extract => (2, 0, vec![param(0), tcx.types.u32], param(1)),
         sym::simd_cast
         | sym::simd_as
         | sym::simd_cast_ptr
         | sym::simd_expose_addr
-        | sym::simd_from_exposed_addr => (2, vec![param(0)], param(1)),
-        sym::simd_bitmask => (2, vec![param(0)], param(1)),
+        | sym::simd_from_exposed_addr => (2, 0, vec![param(0)], param(1)),
+        sym::simd_bitmask => (2, 0, vec![param(0)], param(1)),
         sym::simd_select | sym::simd_select_bitmask => {
-            (2, vec![param(0), param(1), param(1)], param(1))
+            (2, 0, vec![param(0), param(1), param(1)], param(1))
         }
-        sym::simd_reduce_all | sym::simd_reduce_any => (1, vec![param(0)], tcx.types.bool),
+        sym::simd_reduce_all | sym::simd_reduce_any => (1, 0, vec![param(0)], tcx.types.bool),
         sym::simd_reduce_add_ordered | sym::simd_reduce_mul_ordered => {
-            (2, vec![param(0), param(1)], param(1))
+            (2, 0, vec![param(0), param(1)], param(1))
         }
         sym::simd_reduce_add_unordered
         | sym::simd_reduce_mul_unordered
@@ -566,8 +567,9 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_reduce_min
         | sym::simd_reduce_max
         | sym::simd_reduce_min_nanless
-        | sym::simd_reduce_max_nanless => (2, vec![param(0)], param(1)),
-        sym::simd_shuffle => (3, vec![param(0), param(0), param(1)], param(2)),
+        | sym::simd_reduce_max_nanless => (2, 0, vec![param(0)], param(1)),
+        sym::simd_shuffle => (3, 0, vec![param(0), param(0), param(1)], param(2)),
+        sym::simd_shuffle_generic => (2, 1, vec![param(0), param(0)], param(1)),
         _ => {
             let msg = format!("unrecognized platform-specific intrinsic function: `{name}`");
             tcx.sess.struct_span_err(it.span, msg).emit();
@@ -577,5 +579,5 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
 
     let sig = tcx.mk_fn_sig(inputs, output, false, hir::Unsafety::Unsafe, Abi::PlatformIntrinsic);
     let sig = ty::Binder::dummy(sig);
-    equate_intrinsic_type(tcx, it, n_tps, 0, sig)
+    equate_intrinsic_type(tcx, it, n_tps, 0, n_cts, sig)
 }

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -329,41 +329,52 @@ fn bounds_from_generic_predicates<'tcx>(
             _ => {}
         }
     }
-    let generics = if types.is_empty() {
-        "".to_string()
-    } else {
-        format!(
-            "<{}>",
-            types
-                .keys()
-                .filter_map(|t| match t.kind() {
-                    ty::Param(_) => Some(t.to_string()),
-                    // Avoid suggesting the following:
-                    // fn foo<T, <T as Trait>::Bar>(_: T) where T: Trait, <T as Trait>::Bar: Other {}
-                    _ => None,
-                })
-                .collect::<Vec<_>>()
-                .join(", ")
-        )
-    };
+
     let mut where_clauses = vec![];
+    let mut types_str = vec![];
     for (ty, bounds) in types {
-        where_clauses
-            .extend(bounds.into_iter().map(|bound| format!("{}: {}", ty, tcx.def_path_str(bound))));
-    }
-    for projection in &projections {
-        let p = projection.skip_binder();
-        // FIXME: this is not currently supported syntax, we should be looking at the `types` and
-        // insert the associated types where they correspond, but for now let's be "lazy" and
-        // propose this instead of the following valid resugaring:
-        // `T: Trait, Trait::Assoc = K` → `T: Trait<Assoc = K>`
-        where_clauses.push(format!("{} = {}", tcx.def_path_str(p.projection_ty.def_id), p.term));
+        if let ty::Param(_) = ty.kind() {
+            let mut bounds_str = vec![];
+            for bound in bounds {
+                let mut projections_str = vec![];
+                for projection in &projections {
+                    let p = projection.skip_binder();
+                    let alias_ty = p.projection_ty;
+                    if bound == tcx.parent(alias_ty.def_id) && alias_ty.self_ty() == ty {
+                        let name = tcx.item_name(alias_ty.def_id);
+                        projections_str.push(format!("{} = {}", name, p.term));
+                    }
+                }
+                let bound_def_path = tcx.def_path_str(bound);
+                if projections_str.is_empty() {
+                    where_clauses.push(format!("{}: {}", ty, bound_def_path));
+                } else {
+                    bounds_str.push(format!("{}<{}>", bound_def_path, projections_str.join(", ")));
+                }
+            }
+            if bounds_str.is_empty() {
+                types_str.push(ty.to_string());
+            } else {
+                types_str.push(format!("{}: {}", ty, bounds_str.join(" + ")));
+            }
+        } else {
+            // Avoid suggesting the following:
+            // fn foo<T, <T as Trait>::Bar>(_: T) where T: Trait, <T as Trait>::Bar: Other {}
+            where_clauses.extend(
+                bounds.into_iter().map(|bound| format!("{}: {}", ty, tcx.def_path_str(bound))),
+            );
+        }
     }
+
+    let generics =
+        if types_str.is_empty() { "".to_string() } else { format!("<{}>", types_str.join(", ")) };
+
     let where_clauses = if where_clauses.is_empty() {
-        String::new()
+        "".to_string()
     } else {
         format!(" where {}", where_clauses.join(", "))
     };
+
     (generics, where_clauses)
 }
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -24,6 +24,9 @@
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
+use rustc_trait_selection::traits::misc::{
+    type_allowed_to_implement_const_param_ty, ConstParamTyImplementationError,
+};
 use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
@@ -865,43 +868,65 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) {
                     );
                 });
             } else {
-                let err_ty_str;
-                let mut is_ptr = true;
-
-                let err = match ty.kind() {
+                let diag = match ty.kind() {
                     ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Error(_) => None,
-                    ty::FnPtr(_) => Some("function pointers"),
-                    ty::RawPtr(_) => Some("raw pointers"),
-                    _ => {
-                        is_ptr = false;
-                        err_ty_str = format!("`{ty}`");
-                        Some(err_ty_str.as_str())
-                    }
+                    ty::FnPtr(_) => Some(tcx.sess.struct_span_err(
+                        hir_ty.span,
+                        "using function pointers as const generic parameters is forbidden",
+                    )),
+                    ty::RawPtr(_) => Some(tcx.sess.struct_span_err(
+                        hir_ty.span,
+                        "using raw pointers as const generic parameters is forbidden",
+                    )),
+                    _ => Some(tcx.sess.struct_span_err(
+                        hir_ty.span,
+                        format!("`{}` is forbidden as the type of a const generic parameter", ty),
+                    )),
                 };
 
-                if let Some(unsupported_type) = err {
-                    if is_ptr {
-                        tcx.sess.span_err(
-                            hir_ty.span,
-                            format!(
-                                "using {unsupported_type} as const generic parameters is forbidden",
-                            ),
-                        );
-                    } else {
-                        let mut err = tcx.sess.struct_span_err(
-                            hir_ty.span,
-                            format!(
-                                "{unsupported_type} is forbidden as the type of a const generic parameter",
-                            ),
-                        );
-                        err.note("the only supported types are integers, `bool` and `char`");
-                        if tcx.sess.is_nightly_build() {
-                            err.help(
-                            "more complex types are supported with `#![feature(adt_const_params)]`",
-                        );
+                if let Some(mut diag) = diag {
+                    diag.note("the only supported types are integers, `bool` and `char`");
+
+                    let cause = ObligationCause::misc(hir_ty.span, param.def_id);
+                    let may_suggest_feature = match type_allowed_to_implement_const_param_ty(
+                        tcx,
+                        tcx.param_env(param.def_id),
+                        ty,
+                        cause,
+                    ) {
+                        // Can never implement `ConstParamTy`, don't suggest anything.
+                        Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed) => false,
+                        // May be able to implement `ConstParamTy`. Only emit the feature help
+                        // if the type is local, since the user may be able to fix the local type.
+                        Err(ConstParamTyImplementationError::InfrigingFields(..)) => {
+                            fn ty_is_local(ty: Ty<'_>) -> bool {
+                                match ty.kind() {
+                                    ty::Adt(adt_def, ..) => adt_def.did().is_local(),
+                                    // Arrays and slices use the inner type's `ConstParamTy`.
+                                    ty::Array(ty, ..) => ty_is_local(*ty),
+                                    ty::Slice(ty) => ty_is_local(*ty),
+                                    // `&` references use the inner type's `ConstParamTy`.
+                                    // `&mut` are not supported.
+                                    ty::Ref(_, ty, ast::Mutability::Not) => ty_is_local(*ty),
+                                    // Say that a tuple is local if any of its components are local.
+                                    // This is not strictly correct, but it's likely that the user can fix the local component.
+                                    ty::Tuple(tys) => tys.iter().any(|ty| ty_is_local(ty)),
+                                    _ => false,
+                                }
+                            }
+
+                            ty_is_local(ty)
                         }
-                        err.emit();
+                        // Implments `ConstParamTy`, suggest adding the feature to enable.
+                        Ok(..) => true,
+                    };
+                    if may_suggest_feature && tcx.sess.is_nightly_build() {
+                        diag.help(
+                            "add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types",
+                        );
                     }
+
+                    diag.emit();
                 }
             }
         }

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -1,11 +1,10 @@
 //! Check properties that are required by built-in traits and set
 //! up data structures required by type-checking/codegen.
 
-use crate::errors::{
-    ConstParamTyImplOnNonAdt, CopyImplOnNonAdt, CopyImplOnTypeWithDtor, DropImplOnWrongItem,
-};
+use crate::errors;
+
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::{struct_span_err, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
@@ -65,7 +64,7 @@ fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
 
     let impl_ = tcx.hir().expect_item(impl_did).expect_impl();
 
-    tcx.sess.emit_err(DropImplOnWrongItem { span: impl_.self_ty.span });
+    tcx.sess.emit_err(errors::DropImplOnWrongItem { span: impl_.self_ty.span });
 }
 
 fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
@@ -91,10 +90,10 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
             infringing_fields_error(tcx, fields, LangItem::Copy, impl_did, span);
         }
         Err(CopyImplementationError::NotAnAdt) => {
-            tcx.sess.emit_err(CopyImplOnNonAdt { span });
+            tcx.sess.emit_err(errors::CopyImplOnNonAdt { span });
         }
         Err(CopyImplementationError::HasDestructor) => {
-            tcx.sess.emit_err(CopyImplOnTypeWithDtor { span });
+            tcx.sess.emit_err(errors::CopyImplOnTypeWithDtor { span });
         }
     }
 }
@@ -117,7 +116,7 @@ fn visit_implementation_of_const_param_ty(tcx: TyCtxt<'_>, impl_did: LocalDefId)
             infringing_fields_error(tcx, fields, LangItem::ConstParamTy, impl_did, span);
         }
         Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed) => {
-            tcx.sess.emit_err(ConstParamTyImplOnNonAdt { span });
+            tcx.sess.emit_err(errors::ConstParamTyImplOnNonAdt { span });
         }
     }
 }
@@ -152,8 +151,6 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
 
     let param_env = tcx.param_env(impl_did);
 
-    let create_err = |msg: &str| struct_span_err!(tcx.sess, span, E0378, "{}", msg);
-
     let infcx = tcx.infer_ctxt().build();
     let cause = ObligationCause::misc(span, impl_did);
 
@@ -176,22 +173,19 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
                 let source_path = tcx.def_path_str(def_a.did());
                 let target_path = tcx.def_path_str(def_b.did());
 
-                create_err(&format!(
-                    "the trait `DispatchFromDyn` may only be implemented \
-                            for a coercion between structures with the same \
-                            definition; expected `{source_path}`, found `{target_path}`",
-                ))
-                .emit();
+                tcx.sess.emit_err(errors::DispatchFromDynCoercion {
+                    span,
+                    trait_name: "DispatchFromDyn",
+                    note: true,
+                    source_path,
+                    target_path,
+                });
 
                 return;
             }
 
             if def_a.repr().c() || def_a.repr().packed() {
-                create_err(
-                    "structs implementing `DispatchFromDyn` may not have \
-                         `#[repr(packed)]` or `#[repr(C)]`",
-                )
-                .emit();
+                tcx.sess.emit_err(errors::DispatchFromDynRepr { span });
             }
 
             let fields = &def_a.non_enum_variant().fields;
@@ -213,16 +207,11 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
                         infcx.at(&cause, param_env).eq(DefineOpaqueTypes::No, ty_a, ty_b)
                     {
                         if ok.obligations.is_empty() {
-                            create_err(
-                                "the trait `DispatchFromDyn` may only be implemented \
-                                 for structs containing the field being coerced, \
-                                 ZST fields with 1 byte alignment, and nothing else",
-                            )
-                            .note(format!(
-                                "extra field `{}` of type `{}` is not allowed",
-                                field.name, ty_a,
-                            ))
-                            .emit();
+                            tcx.sess.emit_err(errors::DispatchFromDynZST {
+                                span,
+                                name: field.name,
+                                ty: ty_a,
+                            });
 
                             return false;
                         }
@@ -233,36 +222,29 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
                 .collect::<Vec<_>>();
 
             if coerced_fields.is_empty() {
-                create_err(
-                    "the trait `DispatchFromDyn` may only be implemented \
-                        for a coercion between structures with a single field \
-                        being coerced, none found",
-                )
-                .emit();
+                tcx.sess.emit_err(errors::DispatchFromDynSingle {
+                    span,
+                    trait_name: "DispatchFromDyn",
+                    note: true,
+                });
             } else if coerced_fields.len() > 1 {
-                create_err("implementing the `DispatchFromDyn` trait requires multiple coercions")
-                    .note(
-                        "the trait `DispatchFromDyn` may only be implemented \
-                            for a coercion between structures with a single field \
-                            being coerced",
-                    )
-                    .note(format!(
-                        "currently, {} fields need coercions: {}",
-                        coerced_fields.len(),
-                        coerced_fields
-                            .iter()
-                            .map(|field| {
-                                format!(
-                                    "`{}` (`{}` to `{}`)",
-                                    field.name,
-                                    field.ty(tcx, args_a),
-                                    field.ty(tcx, args_b),
-                                )
-                            })
-                            .collect::<Vec<_>>()
-                            .join(", ")
-                    ))
-                    .emit();
+                tcx.sess.emit_err(errors::DispatchFromDynMulti {
+                    span,
+                    coercions_note: true,
+                    number: coerced_fields.len(),
+                    coercions: coerced_fields
+                        .iter()
+                        .map(|field| {
+                            format!(
+                                "`{}` (`{}` to `{}`)",
+                                field.name,
+                                field.ty(tcx, args_a),
+                                field.ty(tcx, args_b),
+                            )
+                        })
+                        .collect::<Vec<_>>()
+                        .join(", "),
+                });
             } else {
                 let ocx = ObligationCtxt::new(&infcx);
                 for field in coerced_fields {
@@ -288,11 +270,7 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
             }
         }
         _ => {
-            create_err(
-                "the trait `DispatchFromDyn` may only be implemented \
-                    for a coercion between structures",
-            )
-            .emit();
+            tcx.sess.emit_err(errors::CoerceUnsizedMay { span, trait_name: "DispatchFromDyn" });
         }
     }
 }
@@ -359,17 +337,13 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
             if def_a != def_b {
                 let source_path = tcx.def_path_str(def_a.did());
                 let target_path = tcx.def_path_str(def_b.did());
-                struct_span_err!(
-                    tcx.sess,
+                tcx.sess.emit_err(errors::DispatchFromDynSame {
                     span,
-                    E0377,
-                    "the trait `CoerceUnsized` may only be implemented \
-                           for a coercion between structures with the same \
-                           definition; expected `{}`, found `{}`",
+                    trait_name: "CoerceUnsized",
+                    note: true,
                     source_path,
-                    target_path
-                )
-                .emit();
+                    target_path,
+                });
                 return err_info;
             }
 
@@ -445,15 +419,11 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
                 .collect::<Vec<_>>();
 
             if diff_fields.is_empty() {
-                struct_span_err!(
-                    tcx.sess,
+                tcx.sess.emit_err(errors::CoerceUnsizedOneField {
                     span,
-                    E0374,
-                    "the trait `CoerceUnsized` may only be implemented \
-                           for a coercion between structures with one field \
-                           being coerced, none found"
-                )
-                .emit();
+                    trait_name: "CoerceUnsized",
+                    note: true,
+                });
                 return err_info;
             } else if diff_fields.len() > 1 {
                 let item = tcx.hir().expect_item(impl_did);
@@ -463,29 +433,17 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
                     tcx.def_span(impl_did)
                 };
 
-                struct_span_err!(
-                    tcx.sess,
+                tcx.sess.emit_err(errors::CoerceUnsizedMulti {
                     span,
-                    E0375,
-                    "implementing the trait \
-                                                `CoerceUnsized` requires multiple \
-                                                coercions"
-                )
-                .note(
-                    "`CoerceUnsized` may only be implemented for \
-                          a coercion between structures with one field being coerced",
-                )
-                .note(format!(
-                    "currently, {} fields need coercions: {}",
-                    diff_fields.len(),
-                    diff_fields
+                    coercions_note: true,
+                    number: diff_fields.len(),
+                    coercions: diff_fields
                         .iter()
-                        .map(|&(i, a, b)| { format!("`{}` (`{}` to `{}`)", fields[i].name, a, b) })
+                        .map(|&(i, a, b)| format!("`{}` (`{}` to `{}`)", fields[i].name, a, b))
                         .collect::<Vec<_>>()
-                        .join(", ")
-                ))
-                .span_label(span, "requires multiple coercions")
-                .emit();
+                        .join(", "),
+                });
+
                 return err_info;
             }
 
@@ -495,14 +453,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
         }
 
         _ => {
-            struct_span_err!(
-                tcx.sess,
-                span,
-                E0376,
-                "the trait `CoerceUnsized` may only be implemented \
-                       for a coercion between structures"
-            )
-            .emit();
+            tcx.sess.emit_err(errors::DispatchFromDynStruct { span, trait_name: "CoerceUnsized" });
             return err_info;
         }
     };
@@ -540,13 +491,6 @@ fn infringing_fields_error(
 
     let trait_name = tcx.def_path_str(trait_did);
 
-    let mut err = struct_span_err!(
-        tcx.sess,
-        impl_span,
-        E0204,
-        "the trait `{trait_name}` cannot be implemented for this type"
-    );
-
     // We'll try to suggest constraining type parameters to fulfill the requirements of
     // their `Copy` implementation.
     let mut errors: BTreeMap<_, Vec<_>> = Default::default();
@@ -554,14 +498,15 @@ fn infringing_fields_error(
 
     let mut seen_tys = FxHashSet::default();
 
+    let mut label_spans = Vec::new();
+
     for (field, ty, reason) in fields {
         // Only report an error once per type.
         if !seen_tys.insert(ty) {
             continue;
         }
 
-        let field_span = tcx.def_span(field.did);
-        err.span_label(field_span, format!("this field does not implement `{trait_name}`"));
+        label_spans.push(tcx.def_span(field.did));
 
         match reason {
             InfringingFieldsReason::Fulfill(fulfillment_errors) => {
@@ -625,13 +570,24 @@ fn infringing_fields_error(
             }
         }
     }
+    let mut notes = Vec::new();
     for ((ty, error_predicate), spans) in errors {
         let span: MultiSpan = spans.into();
-        err.span_note(
+        notes.push(errors::ImplForTyRequires {
             span,
-            format!("the `{trait_name}` impl for `{ty}` requires that `{error_predicate}`"),
-        );
+            error_predicate,
+            trait_name: trait_name.clone(),
+            ty,
+        });
     }
+
+    let mut err = tcx.sess.create_err(errors::TraitCannotImplForTy {
+        span: impl_span,
+        trait_name,
+        label_spans,
+        notes,
+    });
+
     suggest_constraining_type_params(
         tcx,
         tcx.hir().get_generics(impl_did).expect("impls always have generics"),

compiler/rustc_hir_analysis/src/collect.rs

@@ -1374,7 +1374,7 @@ fn impl_trait_ref(
                 // make astconv happy.
                 let mut path_segments = ast_trait_ref.path.segments.to_vec();
                 let last_segment = path_segments.len() - 1;
-                let mut args = path_segments[last_segment].args().clone();
+                let mut args = *path_segments[last_segment].args();
                 let last_arg = args.args.len() - 1;
                 assert!(matches!(args.args[last_arg], hir::GenericArg::Const(anon_const) if tcx.has_attr(anon_const.value.def_id, sym::rustc_host)));
                 args.args = &args.args[..args.args.len() - 1];

compiler/rustc_hir_analysis/src/errors.rs

@@ -963,6 +963,25 @@ pub struct InherentTyOutside {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0378")]
+pub struct DispatchFromDynCoercion<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+    #[note(hir_analysis_coercion_between_struct_same_note)]
+    pub note: bool,
+    pub source_path: String,
+    pub target_path: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_dispatch_from_dyn_repr, code = "E0378")]
+pub struct DispatchFromDynRepr {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(hir_analysis_inherent_ty_outside_relevant, code = "E0390")]
 #[help]
@@ -1025,3 +1044,108 @@ pub struct InherentNominal {
     #[label]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_dispatch_from_dyn_zst, code = "E0378")]
+#[note]
+pub struct DispatchFromDynZST<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+    pub ty: Ty<'a>,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0378")]
+pub struct DispatchFromDynSingle<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+    #[note(hir_analysis_coercion_between_struct_single_note)]
+    pub note: bool,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_dispatch_from_dyn_multi, code = "E0378")]
+#[note]
+pub struct DispatchFromDynMulti {
+    #[primary_span]
+    pub span: Span,
+    #[note(hir_analysis_coercions_note)]
+    pub coercions_note: bool,
+    pub number: usize,
+    pub coercions: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0376")]
+pub struct DispatchFromDynStruct<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0377")]
+pub struct DispatchFromDynSame<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+    #[note(hir_analysis_coercion_between_struct_same_note)]
+    pub note: bool,
+    pub source_path: String,
+    pub target_path: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0374")]
+pub struct CoerceUnsizedOneField<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+    #[note(hir_analysis_coercion_between_struct_single_note)]
+    pub note: bool,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_multi, code = "E0375")]
+#[note]
+pub struct CoerceUnsizedMulti {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[note(hir_analysis_coercions_note)]
+    pub coercions_note: bool,
+    pub number: usize,
+    pub coercions: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_coerce_unsized_may, code = "E0378")]
+pub struct CoerceUnsizedMay<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_trait_cannot_impl_for_ty, code = "E0204")]
+pub struct TraitCannotImplForTy {
+    #[primary_span]
+    pub span: Span,
+    pub trait_name: String,
+    #[label]
+    pub label_spans: Vec<Span>,
+    #[subdiagnostic]
+    pub notes: Vec<ImplForTyRequires>,
+}
+
+#[derive(Subdiagnostic)]
+#[note(hir_analysis_requires_note)]
+pub struct ImplForTyRequires {
+    #[primary_span]
+    pub span: MultiSpan,
+    pub error_predicate: String,
+    pub trait_name: String,
+    pub ty: String,
+}

compiler/rustc_hir_typeck/src/demand.rs

@@ -644,7 +644,7 @@ fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
                             if self.can_eq(self.param_env, ty, expected) {
                                 err.span_label(
                                     ex.span,
-                                    format!("expected because of this `break`"),
+                                    "expected because of this `break`",
                                 );
                                 exit = true;
                             }

compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs

@@ -621,7 +621,7 @@ trait defining them",
                         {
                             diag.span_label(
                                 item.span,
-                                format!("associated type is `default` and may be overridden"),
+                                "associated type is `default` and may be overridden",
                             );
                             return true;
                         }

compiler/rustc_lint/src/context.rs

@@ -1316,6 +1316,40 @@ pub fn get_associated_type(
             })
     }
 
+    /// If the given expression is a local binding, find the initializer expression.
+    /// If that initializer expression is another local binding, find its initializer again.
+    ///
+    /// This process repeats as long as possible (but usually no more than once).
+    /// Type-check adjustments are not taken in account in this function.
+    ///
+    /// Examples:
+    /// ```
+    /// let abc = 1;
+    /// let def = abc + 2;
+    /// //        ^^^^^^^ output
+    /// let def = def;
+    /// dbg!(def);
+    /// //   ^^^ input
+    /// ```
+    pub fn expr_or_init<'a>(&self, mut expr: &'a hir::Expr<'tcx>) -> &'a hir::Expr<'tcx> {
+        expr = expr.peel_blocks();
+
+        while let hir::ExprKind::Path(ref qpath) = expr.kind
+            && let Some(parent_node) = match self.qpath_res(qpath, expr.hir_id) {
+                Res::Local(hir_id) => self.tcx.hir().find_parent(hir_id),
+                _ => None,
+            }
+            && let Some(init) = match parent_node {
+                hir::Node::Expr(expr) => Some(expr),
+                hir::Node::Local(hir::Local { init, .. }) => *init,
+                _ => None
+            }
+        {
+            expr = init.peel_blocks();
+        }
+        expr
+    }
+
     /// If the given expression is a local binding, find the initializer expression.
     /// If that initializer expression is another local or **outside** (`const`/`static`)
     /// binding, find its initializer again.
@@ -1338,7 +1372,10 @@ pub fn get_associated_type(
     /// dbg!(def);
     /// //   ^^^ input
     /// ```
-    pub fn expr_or_init<'a>(&self, mut expr: &'a hir::Expr<'tcx>) -> &'a hir::Expr<'tcx> {
+    pub fn expr_or_init_with_outside_body<'a>(
+        &self,
+        mut expr: &'a hir::Expr<'tcx>,
+    ) -> &'a hir::Expr<'tcx> {
         expr = expr.peel_blocks();
 
         while let hir::ExprKind::Path(ref qpath) = expr.kind

compiler/rustc_lint/src/foreign_modules.rs

@@ -5,19 +5,18 @@
 use rustc_middle::query::Providers;
 use rustc_middle::ty::layout::LayoutError;
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
-use rustc_session::lint::{lint_array, LintArray};
 use rustc_span::{sym, Span, Symbol};
 use rustc_target::abi::FIRST_VARIANT;
 
 use crate::lints::{BuiltinClashingExtern, BuiltinClashingExternSub};
-use crate::types;
+use crate::{types, LintVec};
 
 pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers { clashing_extern_declarations, ..*providers };
 }
 
-pub(crate) fn get_lints() -> LintArray {
-    lint_array!(CLASHING_EXTERN_DECLARATIONS)
+pub(crate) fn get_lints() -> LintVec {
+    vec![CLASHING_EXTERN_DECLARATIONS]
 }
 
 fn clashing_extern_declarations(tcx: TyCtxt<'_>, (): ()) {

compiler/rustc_lint/src/invalid_from_utf8.rs

@@ -84,9 +84,9 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
                 )
             };
 
-            let mut init = cx.expr_or_init(arg);
+            let mut init = cx.expr_or_init_with_outside_body(arg);
             while let ExprKind::AddrOf(.., inner) = init.kind {
-                init = cx.expr_or_init(inner);
+                init = cx.expr_or_init_with_outside_body(inner);
             }
             match init.kind {
                 ExprKind::Lit(Spanned { node: lit, .. }) => {

compiler/rustc_lint/src/lib.rs

@@ -130,7 +130,7 @@
 pub use passes::{EarlyLintPass, LateLintPass};
 pub use rustc_session::lint::Level::{self, *};
 pub use rustc_session::lint::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId};
-pub use rustc_session::lint::{LintArray, LintPass};
+pub use rustc_session::lint::{LintPass, LintVec};
 
 fluent_messages! { "../messages.ftl" }
 
@@ -196,7 +196,7 @@ fn lint_mod(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
             BoxPointers: BoxPointers,
             PathStatements: PathStatements,
             LetUnderscore: LetUnderscore,
-            InvalidReferenceCasting: InvalidReferenceCasting::default(),
+            InvalidReferenceCasting: InvalidReferenceCasting,
             // Depends on referenced function signatures in expressions
             UnusedResults: UnusedResults,
             NonUpperCaseGlobals: NonUpperCaseGlobals,

compiler/rustc_lint/src/noop_method_call.rs

@@ -98,6 +98,12 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         let Ok(Some(i)) = ty::Instance::resolve(cx.tcx, cx.param_env, did, args) else { return };
         // (Re)check that it implements the noop diagnostic.
         let Some(name) = cx.tcx.get_diagnostic_name(i.def_id()) else { return };
+        if !matches!(
+            name,
+            sym::noop_method_borrow | sym::noop_method_clone | sym::noop_method_deref
+        ) {
+            return;
+        }
 
         let receiver_ty = cx.typeck_results().expr_ty(receiver);
         let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);

compiler/rustc_lint/src/passes.rs

@@ -111,7 +111,7 @@ impl $name {
                 }
             }
 
-            $v fn get_lints() -> $crate::LintArray {
+            $v fn get_lints() -> $crate::LintVec {
                 let mut lints = Vec::new();
                 $(lints.extend_from_slice(&$pass::get_lints());)*
                 lints
@@ -226,7 +226,7 @@ impl $name {
                 }
             }
 
-            $v fn get_lints() -> $crate::LintArray {
+            $v fn get_lints() -> $crate::LintVec {
                 let mut lints = Vec::new();
                 $(lints.extend_from_slice(&$pass::get_lints());)*
                 lints

compiler/rustc_lint/src/reference_casting.rs

@@ -1,8 +1,7 @@
 use rustc_ast::Mutability;
-use rustc_data_structures::fx::FxHashMap;
-use rustc_hir::{def::Res, Expr, ExprKind, HirId, Local, QPath, StmtKind, UnOp};
+use rustc_hir::{Expr, ExprKind, UnOp};
 use rustc_middle::ty::{self, TypeAndMut};
-use rustc_span::{sym, Span};
+use rustc_span::sym;
 
 use crate::{lints::InvalidReferenceCastingDiag, LateContext, LateLintPass, LintContext};
 
@@ -34,38 +33,18 @@
     "casts of `&T` to `&mut T` without interior mutability"
 }
 
-#[derive(Default)]
-pub struct InvalidReferenceCasting {
-    casted: FxHashMap<HirId, Span>,
-}
-
-impl_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
+declare_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
 
 impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
-    fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx rustc_hir::Stmt<'tcx>) {
-        let StmtKind::Local(local) = stmt.kind else {
-            return;
-        };
-        let Local { init: Some(init), els: None, .. } = local else {
-            return;
-        };
-
-        if is_cast_from_const_to_mut(cx, init) {
-            self.casted.insert(local.pat.hir_id, init.span);
-        }
-    }
-
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         let Some((is_assignment, e)) = is_operation_we_care_about(cx, expr) else {
             return;
         };
 
-        let orig_cast = if is_cast_from_const_to_mut(cx, e) {
-            None
-        } else if let ExprKind::Path(QPath::Resolved(_, path)) = e.kind
-            && let Res::Local(hir_id) = &path.res
-            && let Some(orig_cast) = self.casted.get(hir_id) {
-            Some(*orig_cast)
+        let init = cx.expr_or_init(e);
+
+        let orig_cast = if is_cast_from_const_to_mut(cx, init) {
+            if init.span != e.span { Some(init.span) } else { None }
         } else {
             return;
         };
@@ -125,99 +104,51 @@ fn ptr_write<'tcx>(
     deref_assign_or_addr_of(e).or_else(|| ptr_write(cx, e))
 }
 
-fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> bool {
-    let e = e.peel_blocks();
+fn is_cast_from_const_to_mut<'tcx>(cx: &LateContext<'tcx>, orig_expr: &'tcx Expr<'tcx>) -> bool {
+    let mut need_check_freeze = false;
+    let mut e = orig_expr;
 
-    fn from_casts<'tcx>(
-        cx: &LateContext<'tcx>,
-        e: &'tcx Expr<'tcx>,
-        need_check_freeze: &mut bool,
-    ) -> Option<&'tcx Expr<'tcx>> {
-        // <expr> as *mut ...
-        let mut e = if let ExprKind::Cast(e, t) = e.kind
-            && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(t.hir_id).kind() {
-            e
-        // <expr>.cast_mut()
+    let end_ty = cx.typeck_results().node_type(orig_expr.hir_id);
+
+    // Bail out early if the end type is **not** a mutable pointer.
+    if !matches!(end_ty.kind(), ty::RawPtr(TypeAndMut { ty: _, mutbl: Mutability::Mut })) {
+        return false;
+    }
+
+    loop {
+        e = e.peel_blocks();
+        // <expr> as ...
+        e = if let ExprKind::Cast(expr, _) = e.kind {
+            expr
+        // <expr>.cast(), <expr>.cast_mut() or <expr>.cast_const()
         } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
             && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
-            && cx.tcx.is_diagnostic_item(sym::ptr_cast_mut, def_id) {
+            && matches!(
+                cx.tcx.get_diagnostic_name(def_id),
+                Some(sym::ptr_cast | sym::const_ptr_cast | sym::ptr_cast_mut | sym::ptr_cast_const)
+            )
+        {
             expr
-        // UnsafeCell::raw_get(<expr>)
+        // ptr::from_ref(<expr>), UnsafeCell::raw_get(<expr>) or mem::transmute<_, _>(<expr>)
         } else if let ExprKind::Call(path, [arg]) = e.kind
             && let ExprKind::Path(ref qpath) = path.kind
             && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
-            && cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id)
+            && matches!(
+                cx.tcx.get_diagnostic_name(def_id),
+                Some(sym::ptr_from_ref | sym::unsafe_cell_raw_get | sym::transmute)
+            )
         {
-            *need_check_freeze = true;
+            if cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) {
+                need_check_freeze = true;
+            }
             arg
         } else {
-            return None;
+            break;
         };
-
-        let mut had_at_least_one_cast = false;
-        loop {
-            e = e.peel_blocks();
-            // <expr> as *mut/const ... or <expr> as <uint>
-            e = if let ExprKind::Cast(expr, t) = e.kind
-                && matches!(cx.typeck_results().node_type(t.hir_id).kind(), ty::RawPtr(_) | ty::Uint(_))  {
-                had_at_least_one_cast = true;
-                expr
-            // <expr>.cast(), <expr>.cast_mut() or <expr>.cast_const()
-            } else if let ExprKind::MethodCall(_, expr, [], _) = e.kind
-                && let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id)
-                && matches!(
-                    cx.tcx.get_diagnostic_name(def_id),
-                    Some(sym::ptr_cast | sym::const_ptr_cast | sym::ptr_cast_mut | sym::ptr_cast_const)
-                )
-            {
-                had_at_least_one_cast = true;
-                expr
-            // ptr::from_ref(<expr>) or UnsafeCell::raw_get(<expr>)
-            } else if let ExprKind::Call(path, [arg]) = e.kind
-                && let ExprKind::Path(ref qpath) = path.kind
-                && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
-                && matches!(
-                    cx.tcx.get_diagnostic_name(def_id),
-                    Some(sym::ptr_from_ref | sym::unsafe_cell_raw_get)
-                )
-            {
-                if cx.tcx.is_diagnostic_item(sym::unsafe_cell_raw_get, def_id) {
-                    *need_check_freeze = true;
-                }
-                return Some(arg);
-            } else if had_at_least_one_cast {
-                return Some(e);
-            } else {
-                return None;
-            };
-        }
     }
 
-    fn from_transmute<'tcx>(
-        cx: &LateContext<'tcx>,
-        e: &'tcx Expr<'tcx>,
-    ) -> Option<&'tcx Expr<'tcx>> {
-        // mem::transmute::<_, *mut _>(<expr>)
-        if let ExprKind::Call(path, [arg]) = e.kind
-            && let ExprKind::Path(ref qpath) = path.kind
-            && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id()
-            && cx.tcx.is_diagnostic_item(sym::transmute, def_id)
-            && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Mut, .. }) = cx.typeck_results().node_type(e.hir_id).kind() {
-            Some(arg)
-        } else {
-            None
-        }
-    }
-
-    let mut need_check_freeze = false;
-    let Some(e) = from_casts(cx, e, &mut need_check_freeze).or_else(|| from_transmute(cx, e))
-    else {
-        return false;
-    };
-
-    let e = e.peel_blocks();
-    let node_type = cx.typeck_results().node_type(e.hir_id);
-    if let ty::Ref(_, inner_ty, Mutability::Not) = node_type.kind() {
+    let start_ty = cx.typeck_results().node_type(e.hir_id);
+    if let ty::Ref(_, inner_ty, Mutability::Not) = start_ty.kind() {
         // If an UnsafeCell method is involved we need to additionaly check the
         // inner type for the presence of the Freeze trait (ie does NOT contain
         // an UnsafeCell), since in that case we would incorrectly lint on valid casts.

compiler/rustc_lint_defs/src/lib.rs

@@ -785,16 +785,7 @@ macro_rules! declare_tool_lint {
     );
 }
 
-/// Declares a static `LintArray` and return it as an expression.
-#[macro_export]
-macro_rules! lint_array {
-    ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) };
-    ($( $lint:expr ),*) => {{
-        vec![$($lint),*]
-    }}
-}
-
-pub type LintArray = Vec<&'static Lint>;
+pub type LintVec = Vec<&'static Lint>;
 
 pub trait LintPass {
     fn name(&self) -> &'static str;
@@ -808,7 +799,7 @@ impl $crate::LintPass for $ty {
             fn name(&self) -> &'static str { stringify!($ty) }
         }
         impl $ty {
-            pub fn get_lints() -> $crate::LintArray { $crate::lint_array!($($lint),*) }
+            pub fn get_lints() -> $crate::LintVec { vec![$($lint),*] }
         }
     };
 }

compiler/rustc_middle/src/mir/basic_blocks.rs

@@ -63,11 +63,14 @@ pub fn predecessors(&self) -> &Predecessors {
     }
 
     /// Returns basic blocks in a reverse postorder.
+    ///
+    /// See [`traversal::reverse_postorder`]'s docs to learn what is preorder traversal.
+    ///
+    /// [`traversal::reverse_postorder`]: crate::mir::traversal::reverse_postorder
     #[inline]
     pub fn reverse_postorder(&self) -> &[BasicBlock] {
         self.cache.reverse_postorder.get_or_init(|| {
-            let mut rpo: Vec<_> =
-                Postorder::new(&self.basic_blocks, START_BLOCK).map(|(bb, _)| bb).collect();
+            let mut rpo: Vec<_> = Postorder::new(&self.basic_blocks, START_BLOCK).collect();
             rpo.reverse();
             rpo
         })

compiler/rustc_middle/src/mir/pretty.rs

@@ -1146,10 +1146,10 @@ fn post_fmt_projection(projection: &[PlaceElem<'_>], fmt: &mut Formatter<'_>) ->
             ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
                 write!(fmt, "[-{offset:?} of {min_length:?}]")?;
             }
-            ProjectionElem::Subslice { from, to, from_end: true } if to == 0 => {
+            ProjectionElem::Subslice { from, to: 0, from_end: true } => {
                 write!(fmt, "[{from:?}:]")?;
             }
-            ProjectionElem::Subslice { from, to, from_end: true } if from == 0 => {
+            ProjectionElem::Subslice { from: 0, to, from_end: true } => {
                 write!(fmt, "[:-{to:?}]")?;
             }
             ProjectionElem::Subslice { from, to, from_end: true } => {

compiler/rustc_middle/src/mir/syntax.rs

@@ -139,6 +139,7 @@ pub enum RuntimePhase {
     /// * [`TerminatorKind::Yield`]
     /// * [`TerminatorKind::GeneratorDrop`]
     /// * [`Rvalue::Aggregate`] for any `AggregateKind` except `Array`
+    /// * [`PlaceElem::OpaqueCast`]
     ///
     /// And the following variants are allowed:
     /// * [`StatementKind::Retag`]

compiler/rustc_middle/src/mir/traversal.rs

@@ -41,6 +41,12 @@ pub fn new(body: &'a Body<'tcx>, root: BasicBlock) -> Preorder<'a, 'tcx> {
     }
 }
 
+/// Preorder traversal of a graph.
+///
+/// This function creates an iterator over the `Body`'s basic blocks, that
+/// returns basic blocks in a preorder.
+///
+/// See [`Preorder`]'s docs to learn what is preorder traversal.
 pub fn preorder<'a, 'tcx>(body: &'a Body<'tcx>) -> Preorder<'a, 'tcx> {
     Preorder::new(body, START_BLOCK)
 }
@@ -178,7 +184,7 @@ fn traverse_successor(&mut self) {
         // When we yield `C` and call `traverse_successor`, we push `B` to the stack, but
         // since we've already visited `E`, that child isn't added to the stack. The last
         // two iterations yield `B` and finally `A` for a final traversal of [E, D, C, B, A]
-        while let Some(&mut (_, ref mut iter)) = self.visit_stack.last_mut() && let Some(bb) = iter.next_back() {
+        while let Some(bb) = self.visit_stack.last_mut().and_then(|(_, iter)| iter.next_back()) {
             if self.visited.insert(bb) {
                 if let Some(term) = &self.basic_blocks[bb].terminator {
                     self.visit_stack.push((bb, term.successors()));
@@ -188,16 +194,14 @@ fn traverse_successor(&mut self) {
     }
 }
 
-impl<'a, 'tcx> Iterator for Postorder<'a, 'tcx> {
-    type Item = (BasicBlock, &'a BasicBlockData<'tcx>);
+impl<'tcx> Iterator for Postorder<'_, 'tcx> {
+    type Item = BasicBlock;
 
-    fn next(&mut self) -> Option<(BasicBlock, &'a BasicBlockData<'tcx>)> {
-        let next = self.visit_stack.pop();
-        if next.is_some() {
-            self.traverse_successor();
-        }
+    fn next(&mut self) -> Option<BasicBlock> {
+        let (bb, _) = self.visit_stack.pop()?;
+        self.traverse_successor();
 
-        next.map(|(bb, _)| (bb, &self.basic_blocks[bb]))
+        Some(bb)
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
@@ -215,10 +219,14 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-/// Creates an iterator over the `Body`'s basic blocks, that:
+/// Postorder traversal of a graph.
+///
+/// This function creates an iterator over the `Body`'s basic blocks, that:
 /// - returns basic blocks in a postorder,
 /// - traverses the `BasicBlocks` CFG cache's reverse postorder backwards, and does not cache the
 ///   postorder itself.
+///
+/// See [`Postorder`]'s docs to learn what is postorder traversal.
 pub fn postorder<'a, 'tcx>(
     body: &'a Body<'tcx>,
 ) -> impl Iterator<Item = (BasicBlock, &'a BasicBlockData<'tcx>)> + ExactSizeIterator + DoubleEndedIterator
@@ -226,7 +234,28 @@ pub fn postorder<'a, 'tcx>(
     reverse_postorder(body).rev()
 }
 
-/// Reverse postorder traversal of a graph
+/// Returns an iterator over all basic blocks reachable from the `START_BLOCK` in no particular
+/// order.
+///
+/// This is clearer than writing `preorder` in cases where the order doesn't matter.
+pub fn reachable<'a, 'tcx>(
+    body: &'a Body<'tcx>,
+) -> impl 'a + Iterator<Item = (BasicBlock, &'a BasicBlockData<'tcx>)> {
+    preorder(body)
+}
+
+/// Returns a `BitSet` containing all basic blocks reachable from the `START_BLOCK`.
+pub fn reachable_as_bitset(body: &Body<'_>) -> BitSet<BasicBlock> {
+    let mut iter = preorder(body);
+    iter.by_ref().for_each(drop);
+    iter.visited
+}
+
+/// Reverse postorder traversal of a graph.
+///
+/// This function creates an iterator over the `Body`'s basic blocks, that:
+/// - returns basic blocks in a reverse postorder,
+/// - makes use of the `BasicBlocks` CFG cache's reverse postorder.
 ///
 /// Reverse postorder is the reverse order of a postorder traversal.
 /// This is different to a preorder traversal and represents a natural
@@ -246,65 +275,6 @@ pub fn postorder<'a, 'tcx>(
 /// A reverse postorder traversal of this graph is either `A B C D` or `A C B D`
 /// Note that for a graph containing no loops (i.e., A DAG), this is equivalent to
 /// a topological sort.
-///
-/// Construction of a `ReversePostorder` traversal requires doing a full
-/// postorder traversal of the graph, therefore this traversal should be
-/// constructed as few times as possible. Use the `reset` method to be able
-/// to re-use the traversal
-#[derive(Clone)]
-pub struct ReversePostorder<'a, 'tcx> {
-    body: &'a Body<'tcx>,
-    blocks: Vec<BasicBlock>,
-    idx: usize,
-}
-
-impl<'a, 'tcx> ReversePostorder<'a, 'tcx> {
-    pub fn new(body: &'a Body<'tcx>, root: BasicBlock) -> ReversePostorder<'a, 'tcx> {
-        let blocks: Vec<_> = Postorder::new(&body.basic_blocks, root).map(|(bb, _)| bb).collect();
-        let len = blocks.len();
-        ReversePostorder { body, blocks, idx: len }
-    }
-}
-
-impl<'a, 'tcx> Iterator for ReversePostorder<'a, 'tcx> {
-    type Item = (BasicBlock, &'a BasicBlockData<'tcx>);
-
-    fn next(&mut self) -> Option<(BasicBlock, &'a BasicBlockData<'tcx>)> {
-        if self.idx == 0 {
-            return None;
-        }
-        self.idx -= 1;
-
-        self.blocks.get(self.idx).map(|&bb| (bb, &self.body[bb]))
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        (self.idx, Some(self.idx))
-    }
-}
-
-impl<'a, 'tcx> ExactSizeIterator for ReversePostorder<'a, 'tcx> {}
-
-/// Returns an iterator over all basic blocks reachable from the `START_BLOCK` in no particular
-/// order.
-///
-/// This is clearer than writing `preorder` in cases where the order doesn't matter.
-pub fn reachable<'a, 'tcx>(
-    body: &'a Body<'tcx>,
-) -> impl 'a + Iterator<Item = (BasicBlock, &'a BasicBlockData<'tcx>)> {
-    preorder(body)
-}
-
-/// Returns a `BitSet` containing all basic blocks reachable from the `START_BLOCK`.
-pub fn reachable_as_bitset(body: &Body<'_>) -> BitSet<BasicBlock> {
-    let mut iter = preorder(body);
-    (&mut iter).for_each(drop);
-    iter.visited
-}
-
-/// Creates an iterator over the `Body`'s basic blocks, that:
-/// - returns basic blocks in a reverse postorder,
-/// - makes use of the `BasicBlocks` CFG cache's reverse postorder.
 pub fn reverse_postorder<'a, 'tcx>(
     body: &'a Body<'tcx>,
 ) -> impl Iterator<Item = (BasicBlock, &'a BasicBlockData<'tcx>)> + ExactSizeIterator + DoubleEndedIterator

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -740,9 +740,7 @@ fn non_exhaustive_match<'p, 'tcx>(
                         ));
                 }
             } else if ty == cx.tcx.types.str_ {
-                err.note(format!(
-                    "`&str` cannot be matched exhaustively, so a wildcard `_` is necessary",
-                ));
+                err.note("`&str` cannot be matched exhaustively, so a wildcard `_` is necessary");
             } else if cx.is_foreign_non_exhaustive_enum(ty) {
                 err.note(format!("`{ty}` is marked as non-exhaustive, so a wildcard `_` is necessary to match exhaustively"));
             }

compiler/rustc_mir_dataflow/src/elaborate_drops.rs

@@ -194,6 +194,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
     D: DropElaborator<'b, 'tcx>,
     'tcx: 'b,
 {
+    #[instrument(level = "trace", skip(self), ret)]
     fn place_ty(&self, place: Place<'tcx>) -> Ty<'tcx> {
         place.ty(self.elaborator.body(), self.tcx()).ty
     }
@@ -220,11 +221,9 @@ fn tcx(&self) -> TyCtxt<'tcx> {
     //
     // FIXME: I think we should just control the flags externally,
     // and then we do not need this machinery.
+    #[instrument(level = "debug")]
     pub fn elaborate_drop(&mut self, bb: BasicBlock) {
-        debug!("elaborate_drop({:?}, {:?})", bb, self);
-        let style = self.elaborator.drop_style(self.path, DropFlagMode::Deep);
-        debug!("elaborate_drop({:?}, {:?}): live - {:?}", bb, self, style);
-        match style {
+        match self.elaborator.drop_style(self.path, DropFlagMode::Deep) {
             DropStyle::Dead => {
                 self.elaborator
                     .patch()

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -763,7 +763,7 @@ pub(super) fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span>
         // and `_1` is the `Place` for `somenum`.
         //
         // If and when the Issue is resolved, remove this special case match pattern:
-        StatementKind::FakeRead(box (cause, _)) if cause == FakeReadCause::ForGuardBinding => None,
+        StatementKind::FakeRead(box (FakeReadCause::ForGuardBinding, _)) => None,
 
         // Retain spans from all other statements
         StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding`

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -170,6 +170,7 @@ fn param_env(&self) -> ty::ParamEnv<'tcx> {
         self.ctxt.param_env()
     }
 
+    #[instrument(level = "debug", skip(self), ret)]
     fn drop_style(&self, path: Self::Path, mode: DropFlagMode) -> DropStyle {
         let ((maybe_live, maybe_dead), multipart) = match mode {
             DropFlagMode::Shallow => (self.ctxt.init_data.maybe_live_dead(path), false),

compiler/rustc_mir_transform/src/large_enums.rs

@@ -54,11 +54,8 @@ fn candidate<'tcx>(
         let layout = tcx.layout_of(param_env.and(ty)).ok()?;
         let variants = match &layout.variants {
             Variants::Single { .. } => return None,
-            Variants::Multiple { tag_encoding, .. }
-                if matches!(tag_encoding, TagEncoding::Niche { .. }) =>
-            {
-                return None;
-            }
+            Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, .. } => return None,
+
             Variants::Multiple { variants, .. } if variants.len() <= 1 => return None,
             Variants::Multiple { variants, .. } => variants,
         };

compiler/rustc_mir_transform/src/lib.rs

@@ -480,6 +480,7 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
         // These next passes must be executed together
         &add_call_guards::CriticalCallEdges,
+        &reveal_all::RevealAll, // has to be done before drop elaboration, since we need to drop opaque types, too.
         &elaborate_drops::ElaborateDrops,
         // This will remove extraneous landing pads which are no longer
         // necessary as well as well as forcing any call in a non-unwinding
@@ -526,7 +527,6 @@ fn o1<T>(x: T) -> WithMinOptLevel<T> {
         body,
         &[
             &check_alignment::CheckAlignment,
-            &reveal_all::RevealAll, // has to be done before inlining, since inlined code is in RevealAll mode.
             &lower_slice_len::LowerSliceLenCalls, // has to be done before inlining, otherwise actual call will be almost always inlined. Also simple, so can just do first
             &unreachable_prop::UnreachablePropagation,
             &uninhabited_enum_branching::UninhabitedEnumBranching,

compiler/rustc_mir_transform/src/reveal_all.rs

@@ -8,16 +8,7 @@
 pub struct RevealAll;
 
 impl<'tcx> MirPass<'tcx> for RevealAll {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 3 || super::inline::Inline.is_enabled(sess)
-    }
-
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        // Do not apply this transformation to generators.
-        if body.generator.is_some() {
-            return;
-        }
-
         let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());
         RevealAllVisitor { tcx, param_env }.visit_body_preserves_cfg(body);
     }
@@ -34,6 +25,29 @@ fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
+    #[inline]
+    fn visit_place(
+        &mut self,
+        place: &mut Place<'tcx>,
+        _context: PlaceContext,
+        _location: Location,
+    ) {
+        // Performance optimization: don't reintern if there is no `OpaqueCast` to remove.
+        if place.projection.iter().all(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_))) {
+            return;
+        }
+        // `OpaqueCast` projections are only needed if there are opaque types on which projections are performed.
+        // After the `RevealAll` pass, all opaque types are replaced with their hidden types, so we don't need these
+        // projections anymore.
+        place.projection = self.tcx.mk_place_elems(
+            &place
+                .projection
+                .into_iter()
+                .filter(|elem| !matches!(elem, ProjectionElem::OpaqueCast(_)))
+                .collect::<Vec<_>>(),
+        );
+    }
+
     #[inline]
     fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, _: Location) {
         // We have to use `try_normalize_erasing_regions` here, since it's

compiler/rustc_mir_transform/src/ssa.rs

@@ -78,14 +78,10 @@ pub fn new<'tcx>(body: &Body<'tcx>) -> SsaLocals {
             visitor.assignments[local] = Set1::One(LocationExtended::Arg);
         }
 
-        if body.basic_blocks.len() > 2 {
-            for (bb, data) in traversal::reverse_postorder(body) {
-                visitor.visit_basic_block_data(bb, data);
-            }
-        } else {
-            for (bb, data) in body.basic_blocks.iter_enumerated() {
-                visitor.visit_basic_block_data(bb, data);
-            }
+        // For SSA assignments, a RPO visit will see the assignment before it sees any use.
+        // We only visit reachable nodes: computing `dominates` on an unreachable node ICEs.
+        for (bb, data) in traversal::reverse_postorder(body) {
+            visitor.visit_basic_block_data(bb, data);
         }
 
         for var_debug_info in &body.var_debug_info {

compiler/rustc_parse/messages.ftl

@@ -509,7 +509,7 @@ parse_maybe_fn_typo_with_impl = you might have meant to write `impl` instead of
 
 parse_maybe_recover_from_bad_qpath_stage_2 =
     missing angle brackets in associated item path
-    .suggestion = try: `{$ty}`
+    .suggestion = types that don't start with an identifier need to be surrounded with angle brackets in qualified paths
 
 parse_maybe_recover_from_bad_type_plus =
     expected a path on the left-hand side of `+`, not `{$ty}`

compiler/rustc_parse/src/errors.rs

@@ -59,9 +59,18 @@ pub(crate) enum BadTypePlusSub {
 #[diag(parse_maybe_recover_from_bad_qpath_stage_2)]
 pub(crate) struct BadQPathStage2 {
     #[primary_span]
-    #[suggestion(code = "", applicability = "maybe-incorrect")]
     pub span: Span,
-    pub ty: String,
+    #[subdiagnostic]
+    pub wrap: WrapType,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parse_suggestion, applicability = "machine-applicable")]
+pub(crate) struct WrapType {
+    #[suggestion_part(code = "<")]
+    pub lo: Span,
+    #[suggestion_part(code = ">")]
+    pub hi: Span,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -16,7 +16,7 @@
     StructLiteralBodyWithoutPath, StructLiteralBodyWithoutPathSugg, StructLiteralNeedingParens,
     StructLiteralNeedingParensSugg, SuggAddMissingLetStmt, SuggEscapeIdentifier, SuggRemoveComma,
     TernaryOperator, UnexpectedConstInGenericParam, UnexpectedConstParamDeclaration,
-    UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead,
+    UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType,
 };
 
 use crate::fluent_generated as fluent;
@@ -1589,10 +1589,9 @@ pub(super) fn maybe_recover_from_bad_qpath_stage_2<T: RecoverQPath>(
         self.parse_path_segments(&mut path.segments, T::PATH_STYLE, None)?;
         path.span = ty_span.to(self.prev_token.span);
 
-        let ty_str = self.span_to_snippet(ty_span).unwrap_or_else(|_| pprust::ty_to_string(&ty));
         self.sess.emit_err(BadQPathStage2 {
-            span: path.span,
-            ty: format!("<{}>::{}", ty_str, pprust::path_to_string(&path)),
+            span: ty_span,
+            wrap: WrapType { lo: ty_span.shrink_to_lo(), hi: ty_span.shrink_to_hi() },
         });
 
         let path_span = ty_span.shrink_to_hi(); // Use an empty path since `position == 0`.

compiler/rustc_resolve/src/late.rs

@@ -4140,6 +4140,12 @@ fn resolve_anon_const_manual(
         });
     }
 
+    fn resolve_expr_field(&mut self, f: &'ast ExprField, e: &'ast Expr) {
+        self.resolve_expr(&f.expr, Some(e));
+        self.visit_ident(f.ident);
+        walk_list!(self, visit_attribute, f.attrs.iter());
+    }
+
     fn resolve_expr(&mut self, expr: &'ast Expr, parent: Option<&'ast Expr>) {
         // First, record candidate traits for this expression if it could
         // result in the invocation of a method call.
@@ -4155,7 +4161,19 @@ fn resolve_expr(&mut self, expr: &'ast Expr, parent: Option<&'ast Expr>) {
 
             ExprKind::Struct(ref se) => {
                 self.smart_resolve_path(expr.id, &se.qself, &se.path, PathSource::Struct);
-                visit::walk_expr(self, expr);
+                // This is the same as `visit::walk_expr(self, expr);`, but we want to pass the
+                // parent in for accurate suggestions when encountering `Foo { bar }` that should
+                // have been `Foo { bar: self.bar }`.
+                if let Some(qself) = &se.qself {
+                    self.visit_ty(&qself.ty);
+                }
+                self.visit_path(&se.path, expr.id);
+                walk_list!(self, resolve_expr_field, &se.fields, expr);
+                match &se.rest {
+                    StructRest::Base(expr) => self.visit_expr(expr),
+                    StructRest::Rest(_span) => {}
+                    StructRest::None => {}
+                }
             }
 
             ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -41,7 +41,7 @@
 
 /// A field or associated item from self type suggested in case of resolution failure.
 enum AssocSuggestion {
-    Field,
+    Field(Span),
     MethodWithSelf { called: bool },
     AssocFn { called: bool },
     AssocType,
@@ -51,7 +51,7 @@ enum AssocSuggestion {
 impl AssocSuggestion {
     fn action(&self) -> &'static str {
         match self {
-            AssocSuggestion::Field => "use the available field",
+            AssocSuggestion::Field(_) => "use the available field",
             AssocSuggestion::MethodWithSelf { called: true } => {
                 "call the method with the fully-qualified path"
             }
@@ -186,7 +186,7 @@ fn make_base_error(
                 fallback_label: format!("not a {expected}"),
                 span,
                 span_label: match res {
-                    Res::Def(kind, def_id) if kind == DefKind::TyParam => {
+                    Res::Def(DefKind::TyParam, def_id) => {
                         Some((self.r.def_span(def_id), "found this type parameter"))
                     }
                     _ => None,
@@ -215,7 +215,8 @@ fn make_base_error(
             }
         } else {
             let mut span_label = None;
-            let item_span = path.last().unwrap().ident.span;
+            let item_ident = path.last().unwrap().ident;
+            let item_span = item_ident.span;
             let (mod_prefix, mod_str, module, suggestion) = if path.len() == 1 {
                 debug!(?self.diagnostic_metadata.current_impl_items);
                 debug!(?self.diagnostic_metadata.current_function);
@@ -231,9 +232,35 @@ fn make_base_error(
                     })
                 {
                     let sp = item_span.shrink_to_lo();
+
+                    // Account for `Foo { field }` when suggesting `self.field` so we result on
+                    // `Foo { field: self.field }`.
+                    let field = match source {
+                        PathSource::Expr(Some(Expr { kind: ExprKind::Struct(expr), .. })) => {
+                            expr.fields.iter().find(|f| f.ident == item_ident)
+                        }
+                        _ => None,
+                    };
+                    let pre = if let Some(field) = field && field.is_shorthand {
+                        format!("{item_ident}: ")
+                    } else {
+                        String::new()
+                    };
+                    // Ensure we provide a structured suggestion for an assoc fn only for
+                    // expressions that are actually a fn call.
+                    let is_call = match field {
+                        Some(ast::ExprField { expr, .. }) => {
+                            matches!(expr.kind, ExprKind::Call(..))
+                        }
+                        _ => matches!(
+                            source,
+                            PathSource::Expr(Some(Expr { kind: ExprKind::Call(..), ..})),
+                        ),
+                    };
+
                     match &item.kind {
                         AssocItemKind::Fn(fn_)
-                        if !sig.decl.has_self() && fn_.sig.decl.has_self() => {
+                        if (!sig.decl.has_self() || !is_call) && fn_.sig.decl.has_self() => {
                             // Ensure that we only suggest `self.` if `self` is available,
                             // you can't call `fn foo(&self)` from `fn bar()` (#115992).
                             // We also want to mention that the method exists.
@@ -243,20 +270,28 @@ fn make_base_error(
                             ));
                             None
                         }
+                        AssocItemKind::Fn(fn_)
+                        if !fn_.sig.decl.has_self() && !is_call => {
+                            span_label = Some((
+                                item.ident.span,
+                                "an associated function by that name is available on `Self` here",
+                            ));
+                            None
+                        }
                         AssocItemKind::Fn(fn_) if fn_.sig.decl.has_self() => Some((
                             sp,
                             "consider using the method on `Self`",
-                            "self.".to_string(),
+                            format!("{pre}self."),
                         )),
                         AssocItemKind::Fn(_) => Some((
                             sp,
                             "consider using the associated function on `Self`",
-                            "Self::".to_string(),
+                            format!("{pre}Self::"),
                         )),
                         AssocItemKind::Const(..) => Some((
                             sp,
                             "consider using the associated constant on `Self`",
-                            "Self::".to_string(),
+                            format!("{pre}Self::"),
                         )),
                         _ => None
                     }
@@ -621,17 +656,30 @@ fn try_lookup_name_relaxed(
                 self.lookup_assoc_candidate(ident, ns, is_expected, source.is_call())
             {
                 let self_is_available = self.self_value_is_available(path[0].ident.span);
+                // Account for `Foo { field }` when suggesting `self.field` so we result on
+                // `Foo { field: self.field }`.
+                let pre = match source {
+                    PathSource::Expr(Some(Expr { kind: ExprKind::Struct(expr), .. }))
+                        if expr
+                            .fields
+                            .iter()
+                            .any(|f| f.ident == path[0].ident && f.is_shorthand) =>
+                    {
+                        format!("{path_str}: ")
+                    }
+                    _ => String::new(),
+                };
                 match candidate {
-                    AssocSuggestion::Field => {
+                    AssocSuggestion::Field(field_span) => {
                         if self_is_available {
-                            err.span_suggestion(
-                                span,
+                            err.span_suggestion_verbose(
+                                span.shrink_to_lo(),
                                 "you might have meant to use the available field",
-                                format!("self.{path_str}"),
+                                format!("{pre}self."),
                                 Applicability::MachineApplicable,
                             );
                         } else {
-                            err.span_label(span, "a field by this name exists in `Self`");
+                            err.span_label(field_span, "a field by that name exists in `Self`");
                         }
                     }
                     AssocSuggestion::MethodWithSelf { called } if self_is_available => {
@@ -640,10 +688,10 @@ fn try_lookup_name_relaxed(
                         } else {
                             "you might have meant to refer to the method"
                         };
-                        err.span_suggestion(
-                            span,
+                        err.span_suggestion_verbose(
+                            span.shrink_to_lo(),
                             msg,
-                            format!("self.{path_str}"),
+                            "self.".to_string(),
                             Applicability::MachineApplicable,
                         );
                     }
@@ -651,10 +699,10 @@ fn try_lookup_name_relaxed(
                     | AssocSuggestion::AssocFn { .. }
                     | AssocSuggestion::AssocConst
                     | AssocSuggestion::AssocType => {
-                        err.span_suggestion(
-                            span,
+                        err.span_suggestion_verbose(
+                            span.shrink_to_lo(),
                             format!("you might have meant to {}", candidate.action()),
-                            format!("Self::{path_str}"),
+                            "Self::".to_string(),
                             Applicability::MachineApplicable,
                         );
                     }
@@ -1667,11 +1715,11 @@ fn extract_node_id(t: &Ty) -> Option<NodeId> {
                         resolution.full_res()
                     {
                         if let Some(field_ids) = self.r.field_def_ids(did) {
-                            if field_ids
+                            if let Some(field_id) = field_ids
                                 .iter()
-                                .any(|&field_id| ident.name == self.r.tcx.item_name(field_id))
+                                .find(|&&field_id| ident.name == self.r.tcx.item_name(field_id))
                             {
-                                return Some(AssocSuggestion::Field);
+                                return Some(AssocSuggestion::Field(self.r.def_span(*field_id)));
                             }
                         }
                     }

compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -86,6 +86,10 @@ pub fn impl_def(&mut self, did: DefId) -> stable_mir::ty::ImplDef {
         stable_mir::ty::ImplDef(self.create_def_id(did))
     }
 
+    pub fn region_def(&mut self, did: DefId) -> stable_mir::ty::RegionDef {
+        stable_mir::ty::RegionDef(self.create_def_id(did))
+    }
+
     pub fn prov(&mut self, aid: AllocId) -> stable_mir::ty::Prov {
         stable_mir::ty::Prov(self.create_alloc_id(aid))
     }

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -7,7 +7,8 @@
 //!
 //! For now, we are developing everything inside `rustc`, thus, we keep this module private.
 
-use hir::def::DefKind;
+use crate::rustc_smir::hir::def::DefKind;
+use crate::rustc_smir::stable_mir::ty::{BoundRegion, EarlyBoundRegion, Region};
 use rustc_hir as hir;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{alloc_range, AllocId};
@@ -1500,9 +1501,39 @@ fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
 impl<'tcx> Stable<'tcx> for ty::Region<'tcx> {
     type T = stable_mir::ty::Region;
 
-    fn stable(&self, _: &mut Tables<'tcx>) -> Self::T {
-        // FIXME: add a real implementation of stable regions
-        opaque(self)
+    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        Region { kind: self.kind().stable(tables) }
+    }
+}
+
+impl<'tcx> Stable<'tcx> for ty::RegionKind<'tcx> {
+    type T = stable_mir::ty::RegionKind;
+
+    fn stable(&self, tables: &mut Tables<'tcx>) -> Self::T {
+        use stable_mir::ty::RegionKind;
+        match self {
+            ty::ReEarlyBound(early_reg) => RegionKind::ReEarlyBound(EarlyBoundRegion {
+                def_id: tables.region_def(early_reg.def_id),
+                index: early_reg.index,
+                name: early_reg.name.to_string(),
+            }),
+            ty::ReLateBound(db_index, bound_reg) => RegionKind::ReLateBound(
+                db_index.as_u32(),
+                BoundRegion { var: bound_reg.var.as_u32(), kind: bound_reg.kind.stable(tables) },
+            ),
+            ty::ReStatic => RegionKind::ReStatic,
+            ty::RePlaceholder(place_holder) => {
+                RegionKind::RePlaceholder(stable_mir::ty::Placeholder {
+                    universe: place_holder.universe.as_u32(),
+                    bound: BoundRegion {
+                        var: place_holder.bound.var.as_u32(),
+                        kind: place_holder.bound.kind.stable(tables),
+                    },
+                })
+            }
+            ty::ReErased => RegionKind::ReErased,
+            _ => unreachable!("{self:?}"),
+        }
     }
 }
 

compiler/rustc_span/src/lib.rs

@@ -1753,7 +1753,7 @@ pub fn original_relative_byte_pos(&self, pos: BytePos) -> RelativeBytePos {
         // is recorded.
         let diff = match self.normalized_pos.binary_search_by(|np| np.pos.cmp(&pos)) {
             Ok(i) => self.normalized_pos[i].diff,
-            Err(i) if i == 0 => 0,
+            Err(0) => 0,
             Err(i) => self.normalized_pos[i - 1].diff,
         };
 
@@ -1775,7 +1775,7 @@ pub fn normalized_byte_pos(&self, offset: u32) -> BytePos {
             .binary_search_by(|np| (np.pos.0 + np.diff).cmp(&(self.start_pos.0 + offset)))
         {
             Ok(i) => self.normalized_pos[i].diff,
-            Err(i) if i == 0 => 0,
+            Err(0) => 0,
             Err(i) => self.normalized_pos[i - 1].diff,
         };
 

compiler/rustc_span/src/symbol.rs

@@ -1465,6 +1465,7 @@
         simd_shl,
         simd_shr,
         simd_shuffle,
+        simd_shuffle_generic,
         simd_sub,
         simd_trunc,
         simd_xor,

compiler/rustc_trait_selection/src/solve/search_graph/cache.rs

@@ -1,102 +0,0 @@
-//! This module both handles the global cache which stores "finished" goals,
-//! and the provisional cache which contains partially computed goals.
-//!
-//! The provisional cache is necessary when dealing with coinductive cycles.
-//!
-//! For more information about the provisional cache and coinduction in general,
-//! check out the relevant section of the rustc-dev-guide.
-//!
-//! FIXME(@lcnr): Write that section, feel free to ping me if you need help here
-//! before then or if I still haven't done that before January 2023.
-use super::StackDepth;
-use rustc_data_structures::fx::FxHashMap;
-use rustc_index::IndexVec;
-use rustc_middle::traits::solve::{CanonicalInput, QueryResult};
-
-rustc_index::newtype_index! {
-    pub struct EntryIndex {}
-}
-
-#[derive(Debug, Clone)]
-pub(super) struct ProvisionalEntry<'tcx> {
-    /// In case we have a coinductive cycle, this is the
-    /// the current provisional result of this goal.
-    ///
-    /// This starts out as `None` for all goals and gets to some
-    /// when the goal gets popped from the stack or we rerun evaluation
-    /// for this goal to reach a fixpoint.
-    pub(super) response: Option<QueryResult<'tcx>>,
-    /// In case of a cycle, the position of deepest stack entry involved
-    /// in that cycle. This is monotonically decreasing in the stack as all
-    /// elements between the current stack element in the deepest stack entry
-    /// involved have to also be involved in that cycle.
-    ///
-    /// We can only move entries to the global cache once we're complete done
-    /// with the cycle. If this entry has not been involved in a cycle,
-    /// this is just its own depth.
-    pub(super) depth: StackDepth,
-
-    /// The goal for this entry. Should always be equal to the corresponding goal
-    /// in the lookup table.
-    pub(super) input: CanonicalInput<'tcx>,
-}
-
-pub(super) struct ProvisionalCache<'tcx> {
-    pub(super) entries: IndexVec<EntryIndex, ProvisionalEntry<'tcx>>,
-    // FIXME: This is only used to quickly check whether a given goal
-    // is in the cache. We should experiment with using something like
-    // `SsoHashSet` here because in most cases there are only a few entries.
-    pub(super) lookup_table: FxHashMap<CanonicalInput<'tcx>, EntryIndex>,
-}
-
-impl<'tcx> ProvisionalCache<'tcx> {
-    pub(super) fn empty() -> ProvisionalCache<'tcx> {
-        ProvisionalCache { entries: Default::default(), lookup_table: Default::default() }
-    }
-
-    pub(super) fn is_empty(&self) -> bool {
-        self.entries.is_empty() && self.lookup_table.is_empty()
-    }
-
-    /// Adds a dependency from the current leaf to `target` in the cache
-    /// to prevent us from moving any goals which depend on the current leaf
-    /// to the global cache while we're still computing `target`.
-    ///
-    /// Its important to note that `target` may already be part of a different cycle.
-    /// In this case we have to ensure that we also depend on all other goals
-    /// in the existing cycle in addition to the potentially direct cycle with `target`.
-    pub(super) fn add_dependency_of_leaf_on(&mut self, target: EntryIndex) {
-        let depth = self.entries[target].depth;
-        for provisional_entry in &mut self.entries.raw[target.index()..] {
-            // The depth of `target` is the position of the deepest goal in the stack
-            // on which `target` depends. That goal is the `root` of this cycle.
-            //
-            // Any entry which was added after `target` is either on the stack itself
-            // at which point its depth is definitely at least as high as the depth of
-            // `root`. If it's not on the stack itself it has to depend on a goal
-            // between `root` and `leaf`. If it were to depend on a goal deeper in the
-            // stack than `root`, then `root` would also depend on that goal, at which
-            // point `root` wouldn't be the root anymore.
-            debug_assert!(provisional_entry.depth >= depth);
-            provisional_entry.depth = depth;
-        }
-
-        // We only update entries which were added after `target` as no other
-        // entry should have a higher depth.
-        //
-        // Any entry which previously had a higher depth than target has to
-        // be between `target` and `root`. Because of this we would have updated
-        // its depth when calling `add_dependency_of_leaf_on(root)` for `target`.
-        if cfg!(debug_assertions) {
-            self.entries.iter().all(|e| e.depth <= depth);
-        }
-    }
-
-    pub(super) fn depth(&self, entry_index: EntryIndex) -> StackDepth {
-        self.entries[entry_index].depth
-    }
-
-    pub(super) fn provisional_result(&self, entry_index: EntryIndex) -> Option<QueryResult<'tcx>> {
-        self.entries[entry_index].response
-    }
-}

compiler/rustc_trait_selection/src/solve/search_graph/mod.rs

@@ -1,10 +1,7 @@
-mod cache;
-
-use self::cache::ProvisionalEntry;
 use super::inspect;
 use super::inspect::ProofTreeBuilder;
 use super::SolverMode;
-use cache::ProvisionalCache;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_index::Idx;
 use rustc_index::IndexVec;
@@ -27,8 +24,14 @@ struct StackEntry<'tcx> {
     // The maximum depth reached by this stack entry, only up-to date
     // for the top of the stack and lazily updated for the rest.
     reached_depth: StackDepth,
+    // In case of a cycle, the depth of the root.
+    cycle_root_depth: StackDepth,
+
     encountered_overflow: bool,
     has_been_used: bool,
+    /// Starts out as `None` and gets set when rerunning this
+    /// goal in case we encounter a cycle.
+    provisional_result: Option<QueryResult<'tcx>>,
 
     /// We put only the root goal of a coinductive cycle into the global cache.
     ///
@@ -47,7 +50,7 @@ pub(super) struct SearchGraph<'tcx> {
     ///
     /// An element is *deeper* in the stack if its index is *lower*.
     stack: IndexVec<StackDepth, StackEntry<'tcx>>,
-    provisional_cache: ProvisionalCache<'tcx>,
+    stack_entries: FxHashMap<CanonicalInput<'tcx>, StackDepth>,
 }
 
 impl<'tcx> SearchGraph<'tcx> {
@@ -56,7 +59,7 @@ pub(super) fn new(tcx: TyCtxt<'tcx>, mode: SolverMode) -> SearchGraph<'tcx> {
             mode,
             local_overflow_limit: tcx.recursion_limit().0.checked_ilog2().unwrap_or(0) as usize,
             stack: Default::default(),
-            provisional_cache: ProvisionalCache::empty(),
+            stack_entries: Default::default(),
         }
     }
 
@@ -85,6 +88,7 @@ fn on_cache_hit(&mut self, additional_depth: usize, encountered_overflow: bool)
     /// would cause us to not track overflow and recursion depth correctly.
     fn pop_stack(&mut self) -> StackEntry<'tcx> {
         let elem = self.stack.pop().unwrap();
+        assert!(self.stack_entries.remove(&elem.input).is_some());
         if let Some(last) = self.stack.raw.last_mut() {
             last.reached_depth = last.reached_depth.max(elem.reached_depth);
             last.encountered_overflow |= elem.encountered_overflow;
@@ -104,22 +108,17 @@ pub(super) fn global_cache(&self, tcx: TyCtxt<'tcx>) -> &'tcx EvaluationCache<'t
     }
 
     pub(super) fn is_empty(&self) -> bool {
-        self.stack.is_empty() && self.provisional_cache.is_empty()
+        self.stack.is_empty()
     }
 
     /// Whether we're currently in a cycle. This should only be used
     /// for debug assertions.
     pub(super) fn in_cycle(&self) -> bool {
         if let Some(stack_depth) = self.stack.last_index() {
-            // Either the current goal on the stack is the root of a cycle...
-            if self.stack[stack_depth].has_been_used {
-                return true;
-            }
-
-            // ...or it depends on a goal with a lower depth.
-            let current_goal = self.stack[stack_depth].input;
-            let entry_index = self.provisional_cache.lookup_table[&current_goal];
-            self.provisional_cache.entries[entry_index].depth != stack_depth
+            // Either the current goal on the stack is the root of a cycle
+            // or it depends on a goal with a lower depth.
+            self.stack[stack_depth].has_been_used
+                || self.stack[stack_depth].cycle_root_depth != stack_depth
         } else {
             false
         }
@@ -211,9 +210,8 @@ pub(super) fn with_new_goal(
             }
         }
 
-        // Look at the provisional cache to detect cycles.
-        let cache = &mut self.provisional_cache;
-        match cache.lookup_table.entry(input) {
+        // Check whether we're in a cycle.
+        match self.stack_entries.entry(input) {
             // No entry, we push this goal on the stack and try to prove it.
             Entry::Vacant(v) => {
                 let depth = self.stack.next_index();
@@ -221,14 +219,14 @@ pub(super) fn with_new_goal(
                     input,
                     available_depth,
                     reached_depth: depth,
+                    cycle_root_depth: depth,
                     encountered_overflow: false,
                     has_been_used: false,
+                    provisional_result: None,
                     cycle_participants: Default::default(),
                 };
                 assert_eq!(self.stack.push(entry), depth);
-                let entry_index =
-                    cache.entries.push(ProvisionalEntry { response: None, depth, input });
-                v.insert(entry_index);
+                v.insert(depth);
             }
             // We have a nested goal which relies on a goal `root` deeper in the stack.
             //
@@ -239,41 +237,50 @@ pub(super) fn with_new_goal(
             //
             // Finally we can return either the provisional response for that goal if we have a
             // coinductive cycle or an ambiguous result if the cycle is inductive.
-            Entry::Occupied(entry_index) => {
+            Entry::Occupied(entry) => {
                 inspect.goal_evaluation_kind(inspect::WipCanonicalGoalEvaluationKind::CacheHit(
                     CacheHit::Provisional,
                 ));
 
-                let entry_index = *entry_index.get();
-                let stack_depth = cache.depth(entry_index);
+                let stack_depth = *entry.get();
                 debug!("encountered cycle with depth {stack_depth:?}");
-
-                cache.add_dependency_of_leaf_on(entry_index);
-                let mut iter = self.stack.iter_mut();
-                let root = iter.nth(stack_depth.as_usize()).unwrap();
-                for e in iter {
-                    root.cycle_participants.insert(e.input);
+                // We start by updating the root depth of all cycle participants, and
+                // add all cycle participants to the root.
+                let root_depth = self.stack[stack_depth].cycle_root_depth;
+                let (prev, participants) = self.stack.raw.split_at_mut(stack_depth.as_usize() + 1);
+                let root = &mut prev[root_depth.as_usize()];
+                for entry in participants {
+                    debug_assert!(entry.cycle_root_depth >= root_depth);
+                    entry.cycle_root_depth = root_depth;
+                    root.cycle_participants.insert(entry.input);
+                    // FIXME(@lcnr): I believe that this line is needed as we could
+                    // otherwise access a cache entry for the root of a cycle while
+                    // computing the result for a cycle participant. This can result
+                    // in unstable results due to incompleteness.
+                    //
+                    // However, a test for this would be an even more complex version of
+                    // tests/ui/traits/new-solver/coinduction/incompleteness-unstable-result.rs.
+                    // I did not bother to write such a test and we have no regression test
+                    // for this. It would be good to have such a test :)
+                    #[allow(rustc::potential_query_instability)]
+                    root.cycle_participants.extend(entry.cycle_participants.drain());
                 }
 
-                // If we're in a cycle, we have to retry proving the current goal
-                // until we reach a fixpoint.
+                // If we're in a cycle, we have to retry proving the cycle head
+                // until we reach a fixpoint. It is not enough to simply retry the
+                // `root` goal of this cycle.
+                //
+                // See tests/ui/traits/new-solver/cycles/fixpoint-rerun-all-cycle-heads.rs
+                // for an example.
                 self.stack[stack_depth].has_been_used = true;
-                return if let Some(result) = cache.provisional_result(entry_index) {
+                return if let Some(result) = self.stack[stack_depth].provisional_result {
                     result
                 } else {
-                    // If we don't have a provisional result yet, the goal has to
-                    // still be on the stack.
-                    let mut goal_on_stack = false;
-                    let mut is_coinductive = true;
-                    for entry in self.stack.raw[stack_depth.index()..]
+                    // If we don't have a provisional result yet we're in the first iteration,
+                    // so we start with no constraints.
+                    let is_coinductive = self.stack.raw[stack_depth.index()..]
                         .iter()
-                        .skip_while(|entry| entry.input != input)
-                    {
-                        goal_on_stack = true;
-                        is_coinductive &= entry.input.value.goal.predicate.is_coinductive(tcx);
-                    }
-                    debug_assert!(goal_on_stack);
-
+                        .all(|entry| entry.input.value.goal.predicate.is_coinductive(tcx));
                     if is_coinductive {
                         Self::response_no_constraints(tcx, input, Certainty::Yes)
                     } else {
@@ -294,40 +301,25 @@ pub(super) fn with_new_goal(
                 // of the previous iteration is equal to the final result, at which
                 // point we are done.
                 for _ in 0..self.local_overflow_limit() {
-                    let response = prove_goal(self, inspect);
+                    let result = prove_goal(self, inspect);
 
                     // Check whether the current goal is the root of a cycle and whether
                     // we have to rerun because its provisional result differed from the
                     // final result.
-                    //
-                    // Also update the response for this goal stored in the provisional
-                    // cache.
                     let stack_entry = self.pop_stack();
                     debug_assert_eq!(stack_entry.input, input);
-                    let cache = &mut self.provisional_cache;
-                    let provisional_entry_index =
-                        *cache.lookup_table.get(&stack_entry.input).unwrap();
-                    let provisional_entry = &mut cache.entries[provisional_entry_index];
                     if stack_entry.has_been_used
-                        && provisional_entry.response.map_or(true, |r| r != response)
+                        && stack_entry.provisional_result.map_or(true, |r| r != result)
                     {
-                        // If so, update the provisional result for this goal and remove
-                        // all entries whose result depends on this goal from the provisional
-                        // cache...
-                        //
-                        // That's not completely correct, as a nested goal can also only
-                        // depend on a goal which is lower in the stack so it doesn't
-                        // actually depend on the current goal. This should be fairly
-                        // rare and is hopefully not relevant for performance.
-                        provisional_entry.response = Some(response);
-                        #[allow(rustc::potential_query_instability)]
-                        cache.lookup_table.retain(|_key, index| *index <= provisional_entry_index);
-                        cache.entries.truncate(provisional_entry_index.index() + 1);
-
-                        // ...and finally push our goal back on the stack and reevaluate it.
-                        self.stack.push(StackEntry { has_been_used: false, ..stack_entry });
+                        // If so, update its provisional result and reevaluate it.
+                        let depth = self.stack.push(StackEntry {
+                            has_been_used: false,
+                            provisional_result: Some(result),
+                            ..stack_entry
+                        });
+                        assert_eq!(self.stack_entries.insert(input, depth), None);
                     } else {
-                        return (stack_entry, response);
+                        return (stack_entry, result);
                     }
                 }
 
@@ -343,17 +335,7 @@ pub(super) fn with_new_goal(
         //
         // It is not possible for any nested goal to depend on something deeper on the
         // stack, as this would have also updated the depth of the current goal.
-        let cache = &mut self.provisional_cache;
-        let provisional_entry_index = *cache.lookup_table.get(&input).unwrap();
-        let provisional_entry = &mut cache.entries[provisional_entry_index];
-        let depth = provisional_entry.depth;
-        if depth == self.stack.next_index() {
-            for (i, entry) in cache.entries.drain_enumerated(provisional_entry_index.index()..) {
-                let actual_index = cache.lookup_table.remove(&entry.input);
-                debug_assert_eq!(Some(i), actual_index);
-                debug_assert!(entry.depth == depth);
-            }
-
+        if final_entry.cycle_root_depth == self.stack.next_index() {
             // When encountering a cycle, both inductive and coinductive, we only
             // move the root into the global cache. We also store all other cycle
             // participants involved.
@@ -371,8 +353,6 @@ pub(super) fn with_new_goal(
                 dep_node,
                 result,
             )
-        } else {
-            provisional_entry.response = Some(result);
         }
 
         result

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

@@ -3211,7 +3211,7 @@ fn report_opaque_type_auto_trait_leakage(
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         let name = match self.tcx.opaque_type_origin(def_id.expect_local()) {
             hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) => {
-                format!("opaque type")
+                "opaque type".to_string()
             }
             hir::OpaqueTyOrigin::TyAlias { .. } => {
                 format!("`{}`", self.tcx.def_path_debug_str(def_id))

compiler/stable_mir/src/fold.rs

@@ -4,17 +4,20 @@
 
 use super::ty::{
     Allocation, Binder, Const, ConstDef, ConstantKind, ExistentialPredicate, FnSig, GenericArgKind,
-    GenericArgs, Promoted, RigidTy, TermKind, Ty, TyKind, UnevaluatedConst,
+    GenericArgs, Promoted, Region, RigidTy, TermKind, Ty, TyKind, UnevaluatedConst,
 };
 
 pub trait Folder: Sized {
     type Break;
-    fn visit_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
+    fn fold_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
         ty.super_fold(self)
     }
     fn fold_const(&mut self, c: &Const) -> ControlFlow<Self::Break, Const> {
         c.super_fold(self)
     }
+    fn fold_reg(&mut self, reg: &Region) -> ControlFlow<Self::Break, Region> {
+        reg.super_fold(self)
+    }
 }
 
 pub trait Foldable: Sized + Clone {
@@ -26,7 +29,7 @@ fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
 
 impl Foldable for Ty {
     fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
-        folder.visit_ty(self)
+        folder.fold_ty(self)
     }
     fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
         let mut kind = self.kind();
@@ -81,7 +84,7 @@ fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
 
 impl Foldable for ConstDef {
     fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
-        ControlFlow::Continue(self.clone())
+        ControlFlow::Continue(*self)
     }
 }
 
@@ -96,7 +99,7 @@ fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
 
 impl Foldable for Promoted {
     fn super_fold<V: Folder>(&self, _folder: &mut V) -> ControlFlow<V::Break, Self> {
-        ControlFlow::Continue(self.clone())
+        ControlFlow::Continue(*self)
     }
 }
 
@@ -106,6 +109,15 @@ fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
     }
 }
 
+impl Foldable for Region {
+    fn fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
+        folder.fold_reg(self)
+    }
+    fn super_fold<V: Folder>(&self, _: &mut V) -> ControlFlow<V::Break, Self> {
+        ControlFlow::Continue(self.clone())
+    }
+}
+
 impl Foldable for GenericArgKind {
     fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
         let mut this = self.clone();
@@ -136,7 +148,10 @@ fn super_fold<V: Folder>(&self, folder: &mut V) -> ControlFlow<V::Break, Self> {
             }
             RigidTy::Slice(inner) => *inner = inner.fold(folder)?,
             RigidTy::RawPtr(ty, _) => *ty = ty.fold(folder)?,
-            RigidTy::Ref(_, ty, _) => *ty = ty.fold(folder)?,
+            RigidTy::Ref(reg, ty, _) => {
+                *reg = reg.fold(folder)?;
+                *ty = ty.fold(folder)?
+            }
             RigidTy::FnDef(_, args) => *args = args.fold(folder)?,
             RigidTy::FnPtr(sig) => *sig = sig.fold(folder)?,
             RigidTy::Closure(_, args) => *args = args.fold(folder)?,
@@ -214,7 +229,7 @@ pub enum Never {}
 impl Folder for GenericArgs {
     type Break = Never;
 
-    fn visit_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
+    fn fold_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break, Ty> {
         ControlFlow::Continue(match ty.kind() {
             TyKind::Param(p) => self[p],
             _ => *ty,

compiler/stable_mir/src/ty.rs

@@ -1,7 +1,7 @@
 use super::{
     mir::Safety,
     mir::{Body, Mutability},
-    with, AllocId, DefId,
+    with, AllocId, DefId, Symbol,
 };
 use crate::Opaque;
 use std::fmt::{self, Debug, Formatter};
@@ -34,7 +34,46 @@ pub struct Const {
 }
 
 type Ident = Opaque;
-pub type Region = Opaque;
+
+#[derive(Debug, Clone)]
+pub struct Region {
+    pub kind: RegionKind,
+}
+
+#[derive(Debug, Clone)]
+pub enum RegionKind {
+    ReEarlyBound(EarlyBoundRegion),
+    ReLateBound(DebruijnIndex, BoundRegion),
+    ReStatic,
+    RePlaceholder(Placeholder<BoundRegion>),
+    ReErased,
+}
+
+pub(crate) type DebruijnIndex = u32;
+
+#[derive(Debug, Clone)]
+pub struct EarlyBoundRegion {
+    pub def_id: RegionDef,
+    pub index: u32,
+    pub name: Symbol,
+}
+
+pub(crate) type BoundVar = u32;
+
+#[derive(Debug, Clone)]
+pub struct BoundRegion {
+    pub var: BoundVar,
+    pub kind: BoundRegionKind,
+}
+
+pub(crate) type UniverseIndex = u32;
+
+#[derive(Debug, Clone)]
+pub struct Placeholder<T> {
+    pub universe: UniverseIndex,
+    pub bound: T,
+}
+
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub struct Span(pub usize);
 
@@ -152,6 +191,9 @@ pub fn body(&self) -> Body {
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct ImplDef(pub DefId);
 
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct RegionDef(pub DefId);
+
 #[derive(Clone, Debug)]
 pub struct GenericArgs(pub Vec<GenericArgKind>);
 

compiler/stable_mir/src/visitor.rs

@@ -4,7 +4,7 @@
 
 use super::ty::{
     Allocation, Binder, Const, ConstDef, ExistentialPredicate, FnSig, GenericArgKind, GenericArgs,
-    Promoted, RigidTy, TermKind, Ty, UnevaluatedConst,
+    Promoted, Region, RigidTy, TermKind, Ty, UnevaluatedConst,
 };
 
 pub trait Visitor: Sized {
@@ -15,6 +15,9 @@ fn visit_ty(&mut self, ty: &Ty) -> ControlFlow<Self::Break> {
     fn visit_const(&mut self, c: &Const) -> ControlFlow<Self::Break> {
         c.super_visit(self)
     }
+    fn visit_reg(&mut self, reg: &Region) -> ControlFlow<Self::Break> {
+        reg.super_visit(self)
+    }
 }
 
 pub trait Visitable {
@@ -101,6 +104,16 @@ fn super_visit<V: Visitor>(&self, visitor: &mut V) -> ControlFlow<V::Break> {
     }
 }
 
+impl Visitable for Region {
+    fn visit<V: Visitor>(&self, visitor: &mut V) -> ControlFlow<V::Break> {
+        visitor.visit_reg(self)
+    }
+
+    fn super_visit<V: Visitor>(&self, _: &mut V) -> ControlFlow<V::Break> {
+        ControlFlow::Continue(())
+    }
+}
+
 impl Visitable for GenericArgKind {
     fn super_visit<V: Visitor>(&self, visitor: &mut V) -> ControlFlow<V::Break> {
         match self {
@@ -128,7 +141,10 @@ fn super_visit<V: Visitor>(&self, visitor: &mut V) -> ControlFlow<V::Break> {
             }
             RigidTy::Slice(inner) => inner.visit(visitor),
             RigidTy::RawPtr(ty, _) => ty.visit(visitor),
-            RigidTy::Ref(_, ty, _) => ty.visit(visitor),
+            RigidTy::Ref(reg, ty, _) => {
+                reg.visit(visitor);
+                ty.visit(visitor)
+            }
             RigidTy::FnDef(_, args) => args.visit(visitor),
             RigidTy::FnPtr(sig) => sig.visit(visitor),
             RigidTy::Closure(_, args) => args.visit(visitor),

library/alloc/src/rc.rs

@@ -2408,6 +2408,27 @@ fn from(t: T) -> Self {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "shared_from_array", since = "CURRENT_RUSTC_VERSION")]
+impl<T, const N: usize> From<[T; N]> for Rc<[T]> {
+    /// Converts a [`[T; N]`](prim@array) into an `Rc<[T]>`.
+    ///
+    /// The conversion moves the array into a newly allocated `Rc`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::rc::Rc;
+    /// let original: [i32; 3] = [1, 2, 3];
+    /// let shared: Rc<[i32]> = Rc::from(original);
+    /// assert_eq!(&[1, 2, 3], &shared[..]);
+    /// ```
+    #[inline]
+    fn from(v: [T; N]) -> Rc<[T]> {
+        Rc::<[T; N]>::from(v)
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "shared_from_slice", since = "1.21.0")]
 impl<T: Clone> From<&[T]> for Rc<[T]> {

library/alloc/src/sync.rs

@@ -1618,7 +1618,7 @@ pub fn downgrade(this: &Self) -> Weak<T, A>
     #[must_use]
     #[stable(feature = "arc_counts", since = "1.15.0")]
     pub fn weak_count(this: &Self) -> usize {
-        let cnt = this.inner().weak.load(Acquire);
+        let cnt = this.inner().weak.load(Relaxed);
         // If the weak count is currently locked, the value of the
         // count was 0 just before taking the lock.
         if cnt == usize::MAX { 0 } else { cnt - 1 }
@@ -1648,7 +1648,7 @@ pub fn weak_count(this: &Self) -> usize {
     #[must_use]
     #[stable(feature = "arc_counts", since = "1.15.0")]
     pub fn strong_count(this: &Self) -> usize {
-        this.inner().strong.load(Acquire)
+        this.inner().strong.load(Relaxed)
     }
 
     /// Increments the strong reference count on the `Arc<T>` associated with the
@@ -2803,7 +2803,7 @@ fn checked_increment(n: usize) -> Option<usize> {
     #[must_use]
     #[stable(feature = "weak_counts", since = "1.41.0")]
     pub fn strong_count(&self) -> usize {
-        if let Some(inner) = self.inner() { inner.strong.load(Acquire) } else { 0 }
+        if let Some(inner) = self.inner() { inner.strong.load(Relaxed) } else { 0 }
     }
 
     /// Gets an approximation of the number of `Weak` pointers pointing to this
@@ -2822,7 +2822,7 @@ pub fn strong_count(&self) -> usize {
     pub fn weak_count(&self) -> usize {
         if let Some(inner) = self.inner() {
             let weak = inner.weak.load(Acquire);
-            let strong = inner.strong.load(Acquire);
+            let strong = inner.strong.load(Relaxed);
             if strong == 0 {
                 0
             } else {
@@ -3269,6 +3269,27 @@ fn from(t: T) -> Self {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "shared_from_array", since = "CURRENT_RUSTC_VERSION")]
+impl<T, const N: usize> From<[T; N]> for Arc<[T]> {
+    /// Converts a [`[T; N]`](prim@array) into an `Arc<[T]>`.
+    ///
+    /// The conversion moves the array into a newly allocated `Arc`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::sync::Arc;
+    /// let original: [i32; 3] = [1, 2, 3];
+    /// let shared: Arc<[i32]> = Arc::from(original);
+    /// assert_eq!(&[1, 2, 3], &shared[..]);
+    /// ```
+    #[inline]
+    fn from(v: [T; N]) -> Arc<[T]> {
+        Arc::<[T; N]>::from(v)
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "shared_from_slice", since = "1.21.0")]
 impl<T: Clone> From<&[T]> for Arc<[T]> {

library/alloc/src/vec/mod.rs

@@ -3154,6 +3154,36 @@ fn from(s: &mut [T]) -> Vec<T> {
     }
 }
 
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array_ref", since = "CURRENT_RUSTC_VERSION")]
+impl<T: Clone, const N: usize> From<&[T; N]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&[1, 2, 3]), vec![1, 2, 3]);
+    /// ```
+    fn from(s: &[T; N]) -> Vec<T> {
+        Self::from(s.as_slice())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array_ref", since = "CURRENT_RUSTC_VERSION")]
+impl<T: Clone, const N: usize> From<&mut [T; N]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
+    /// ```
+    fn from(s: &mut [T; N]) -> Vec<T> {
+        Self::from(s.as_mut_slice())
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "vec_from_array", since = "1.44.0")]
 impl<T, const N: usize> From<[T; N]> for Vec<T> {

library/alloc/tests/vec.rs

@@ -2562,3 +2562,13 @@ unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
     // Ensure all ZSTs have been freed.
     assert!(alloc.state.borrow().0.is_empty());
 }
+
+#[test]
+fn test_vec_from_array_ref() {
+    assert_eq!(Vec::from(&[1, 2, 3]), vec![1, 2, 3]);
+}
+
+#[test]
+fn test_vec_from_array_mut_ref() {
+    assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
+}

library/core/src/cmp.rs

@@ -291,9 +291,9 @@ fn ne(&self, other: &Rhs) -> bool {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Eq"]
 pub trait Eq: PartialEq<Self> {
-    // this method is used solely by #[deriving] to assert
-    // that every component of a type implements #[deriving]
-    // itself, the current deriving infrastructure means doing this
+    // this method is used solely by #[derive(Eq)] to assert
+    // that every component of a type implements `Eq`
+    // itself. The current deriving infrastructure means doing this
     // assertion without using a method on this trait is nearly
     // impossible.
     //

library/core/src/fmt/mod.rs

@@ -112,9 +112,9 @@ pub trait Write {
     ///
     /// # Errors
     ///
-    /// This function will return an instance of [`Error`] on error.
+    /// This function will return an instance of [`std::fmt::Error`][Error] on error.
     ///
-    /// The purpose of std::fmt::Error is to abort the formatting operation when the underlying
+    /// The purpose of that error is to abort the formatting operation when the underlying
     /// destination encounters some error preventing it from accepting more text; it should
     /// generally be propagated rather than handled, at least when implementing formatting traits.
     ///

library/core/src/lib.rs

@@ -178,6 +178,7 @@
 #![feature(ip)]
 #![feature(ip_bits)]
 #![feature(is_ascii_octdigit)]
+#![feature(isqrt)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(ptr_alignment_type)]
 #![feature(ptr_metadata)]

library/core/src/num/int_macros.rs

@@ -898,6 +898,30 @@ pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
             acc.checked_mul(base)
         }
 
+        /// Returns the square root of the number, rounded down.
+        ///
+        /// Returns `None` if `self` is negative.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        /// ```
+        /// #![feature(isqrt)]
+        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_isqrt(), Some(3));")]
+        /// ```
+        #[unstable(feature = "isqrt", issue = "116226")]
+        #[rustc_const_unstable(feature = "isqrt", issue = "116226")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn checked_isqrt(self) -> Option<Self> {
+            if self < 0 {
+                None
+            } else {
+                Some((self as $UnsignedT).isqrt() as Self)
+            }
+        }
+
         /// Saturating integer addition. Computes `self + rhs`, saturating at the numeric
         /// bounds instead of overflowing.
         ///
@@ -2061,6 +2085,36 @@ pub const fn pow(self, mut exp: u32) -> Self {
             acc * base
         }
 
+        /// Returns the square root of the number, rounded down.
+        ///
+        /// # Panics
+        ///
+        /// This function will panic if `self` is negative.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        /// ```
+        /// #![feature(isqrt)]
+        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
+        /// ```
+        #[unstable(feature = "isqrt", issue = "116226")]
+        #[rustc_const_unstable(feature = "isqrt", issue = "116226")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn isqrt(self) -> Self {
+            // I would like to implement it as
+            // ```
+            // self.checked_isqrt().expect("argument of integer square root must be non-negative")
+            // ```
+            // but `expect` is not yet stable as a `const fn`.
+            match self.checked_isqrt() {
+                Some(sqrt) => sqrt,
+                None => panic!("argument of integer square root must be non-negative"),
+            }
+        }
+
         /// Calculates the quotient of Euclidean division of `self` by `rhs`.
         ///
         /// This computes the integer `q` such that `self = q * rhs + r`, with

library/core/src/num/uint_macros.rs

@@ -1995,6 +1995,54 @@ pub const fn pow(self, mut exp: u32) -> Self {
             acc * base
         }
 
+        /// Returns the square root of the number, rounded down.
+        ///
+        /// # Examples
+        ///
+        /// Basic usage:
+        /// ```
+        /// #![feature(isqrt)]
+        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
+        /// ```
+        #[unstable(feature = "isqrt", issue = "116226")]
+        #[rustc_const_unstable(feature = "isqrt", issue = "116226")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline]
+        pub const fn isqrt(self) -> Self {
+            if self < 2 {
+                return self;
+            }
+
+            // The algorithm is based on the one presented in
+            // <https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Binary_numeral_system_(base_2)>
+            // which cites as source the following C code:
+            // <https://web.archive.org/web/20120306040058/http://medialab.freaknet.org/martin/src/sqrt/sqrt.c>.
+
+            let mut op = self;
+            let mut res = 0;
+            let mut one = 1 << (self.ilog2() & !1);
+
+            while one != 0 {
+                if op >= res + one {
+                    op -= res + one;
+                    res = (res >> 1) + one;
+                } else {
+                    res >>= 1;
+                }
+                one >>= 2;
+            }
+
+            // SAFETY: the result is positive and fits in an integer with half as many bits.
+            // Inform the optimizer about it.
+            unsafe {
+                intrinsics::assume(0 < res);
+                intrinsics::assume(res < 1 << (Self::BITS / 2));
+            }
+
+            res
+        }
+
         /// Performs Euclidean division.
         ///
         /// Since, for the positive integers, all common

library/core/src/ptr/const_ptr.rs

@@ -607,7 +607,16 @@ pub fn mask(self, mask: usize) -> *const T {
     /// Calculates the distance between two pointers. The returned value is in
     /// units of T: the distance in bytes divided by `mem::size_of::<T>()`.
     ///
-    /// This function is the inverse of [`offset`].
+    /// This is equivalent to `(self as isize - origin as isize) / (mem::size_of::<T>() as isize)`,
+    /// except that it has a lot more opportunities for UB, in exchange for the compiler
+    /// better understanding what you are doing.
+    ///
+    /// The primary motivation of this method is for computing the `len` of an array/slice
+    /// of `T` that you are currently representing as a "start" and "end" pointer
+    /// (and "end" is "one past the end" of the array).
+    /// In that case, `end.offset_from(start)` gets you the length of the array.
+    ///
+    /// All of the following safety requirements are trivially satisfied for this usecase.
     ///
     /// [`offset`]: #method.offset
     ///
@@ -616,7 +625,7 @@ pub fn mask(self, mask: usize) -> *const T {
     /// If any of the following conditions are violated, the result is Undefined
     /// Behavior:
     ///
-    /// * Both the starting and other pointer must be either in bounds or one
+    /// * Both `self` and `origin` must be either in bounds or one
     ///   byte past the end of the same [allocated object].
     ///
     /// * Both pointers must be *derived from* a pointer to the same object.
@@ -646,6 +655,14 @@ pub fn mask(self, mask: usize) -> *const T {
     /// (Note that [`offset`] and [`add`] also have a similar limitation and hence cannot be used on
     /// such large allocations either.)
     ///
+    /// The requirement for pointers to be derived from the same allocated object is primarily
+    /// needed for `const`-compatibility: the distance between pointers into *different* allocated
+    /// objects is not known at compile-time. However, the requirement also exists at
+    /// runtime and may be exploited by optimizations. If you wish to compute the difference between
+    /// pointers that are not guaranteed to be from the same allocation, use `(self as isize -
+    /// origin as isize) / mem::size_of::<T>()`.
+    // FIXME: recommend `addr()` instead of `as usize` once that is stable.
+    ///
     /// [`add`]: #method.add
     /// [allocated object]: crate::ptr#allocated-object
     ///
@@ -703,7 +720,7 @@ pub fn mask(self, mask: usize) -> *const T {
     /// units of **bytes**.
     ///
     /// This is purely a convenience for casting to a `u8` pointer and
-    /// using [offset_from][pointer::offset_from] on it. See that method for
+    /// using [`offset_from`][pointer::offset_from] on it. See that method for
     /// documentation and safety requirements.
     ///
     /// For non-`Sized` pointees this operation considers only the data pointers,

library/core/src/ptr/mut_ptr.rs

@@ -781,7 +781,16 @@ pub const fn guaranteed_ne(self, other: *mut T) -> Option<bool>
     /// Calculates the distance between two pointers. The returned value is in
     /// units of T: the distance in bytes divided by `mem::size_of::<T>()`.
     ///
-    /// This function is the inverse of [`offset`].
+    /// This is equivalent to `(self as isize - origin as isize) / (mem::size_of::<T>() as isize)`,
+    /// except that it has a lot more opportunities for UB, in exchange for the compiler
+    /// better understanding what you are doing.
+    ///
+    /// The primary motivation of this method is for computing the `len` of an array/slice
+    /// of `T` that you are currently representing as a "start" and "end" pointer
+    /// (and "end" is "one past the end" of the array).
+    /// In that case, `end.offset_from(start)` gets you the length of the array.
+    ///
+    /// All of the following safety requirements are trivially satisfied for this usecase.
     ///
     /// [`offset`]: pointer#method.offset-1
     ///
@@ -790,7 +799,7 @@ pub const fn guaranteed_ne(self, other: *mut T) -> Option<bool>
     /// If any of the following conditions are violated, the result is Undefined
     /// Behavior:
     ///
-    /// * Both the starting and other pointer must be either in bounds or one
+    /// * Both `self` and `origin` must be either in bounds or one
     ///   byte past the end of the same [allocated object].
     ///
     /// * Both pointers must be *derived from* a pointer to the same object.
@@ -820,6 +829,14 @@ pub const fn guaranteed_ne(self, other: *mut T) -> Option<bool>
     /// (Note that [`offset`] and [`add`] also have a similar limitation and hence cannot be used on
     /// such large allocations either.)
     ///
+    /// The requirement for pointers to be derived from the same allocated object is primarily
+    /// needed for `const`-compatibility: the distance between pointers into *different* allocated
+    /// objects is not known at compile-time. However, the requirement also exists at
+    /// runtime and may be exploited by optimizations. If you wish to compute the difference between
+    /// pointers that are not guaranteed to be from the same allocation, use `(self as isize -
+    /// origin as isize) / mem::size_of::<T>()`.
+    // FIXME: recommend `addr()` instead of `as usize` once that is stable.
+    ///
     /// [`add`]: #method.add
     /// [allocated object]: crate::ptr#allocated-object
     ///
@@ -875,7 +892,7 @@ pub const fn guaranteed_ne(self, other: *mut T) -> Option<bool>
     /// units of **bytes**.
     ///
     /// This is purely a convenience for casting to a `u8` pointer and
-    /// using [offset_from][pointer::offset_from] on it. See that method for
+    /// using [`offset_from`][pointer::offset_from] on it. See that method for
     /// documentation and safety requirements.
     ///
     /// For non-`Sized` pointees this operation considers only the data pointers,

library/core/src/slice/mod.rs

@@ -3410,7 +3410,7 @@ pub fn rotate_left(&mut self, mid: usize) {
     /// assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);
     /// ```
     ///
-    /// Rotate a subslice:
+    /// Rotating a subslice:
     ///
     /// ```
     /// let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];

library/core/src/sync/exclusive.rs

@@ -2,6 +2,8 @@
 
 use core::fmt;
 use core::future::Future;
+use core::marker::Tuple;
+use core::ops::{Generator, GeneratorState};
 use core::pin::Pin;
 use core::task::{Context, Poll};
 
@@ -168,10 +170,52 @@ fn from(t: T) -> Self {
 }
 
 #[unstable(feature = "exclusive_wrapper", issue = "98407")]
-impl<T: Future + ?Sized> Future for Exclusive<T> {
+impl<F, Args> FnOnce<Args> for Exclusive<F>
+where
+    F: FnOnce<Args>,
+    Args: Tuple,
+{
+    type Output = F::Output;
+
+    extern "rust-call" fn call_once(self, args: Args) -> Self::Output {
+        self.into_inner().call_once(args)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<F, Args> FnMut<Args> for Exclusive<F>
+where
+    F: FnMut<Args>,
+    Args: Tuple,
+{
+    extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output {
+        self.get_mut().call_mut(args)
+    }
+}
+
+#[unstable(feature = "exclusive_wrapper", issue = "98407")]
+impl<T> Future for Exclusive<T>
+where
+    T: Future + ?Sized,
+{
     type Output = T::Output;
+
     #[inline]
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         self.get_pin_mut().poll(cx)
     }
 }
+
+#[unstable(feature = "generator_trait", issue = "43122")] // also #98407
+impl<R, G> Generator<R> for Exclusive<G>
+where
+    G: Generator<R> + ?Sized,
+{
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    #[inline]
+    fn resume(self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume(self.get_pin_mut(), arg)
+    }
+}

library/core/tests/lib.rs

@@ -56,6 +56,7 @@
 #![feature(min_specialization)]
 #![feature(numfmt)]
 #![feature(num_midpoint)]
+#![feature(isqrt)]
 #![feature(step_trait)]
 #![feature(str_internals)]
 #![feature(std_internals)]

library/core/tests/num/int_macros.rs

@@ -290,6 +290,38 @@ fn test_pow() {
                 assert_eq!(r.saturating_pow(0), 1 as $T);
             }
 
+            #[test]
+            fn test_isqrt() {
+                assert_eq!($T::MIN.checked_isqrt(), None);
+                assert_eq!((-1 as $T).checked_isqrt(), None);
+                assert_eq!((0 as $T).isqrt(), 0 as $T);
+                assert_eq!((1 as $T).isqrt(), 1 as $T);
+                assert_eq!((2 as $T).isqrt(), 1 as $T);
+                assert_eq!((99 as $T).isqrt(), 9 as $T);
+                assert_eq!((100 as $T).isqrt(), 10 as $T);
+            }
+
+            #[cfg(not(miri))] // Miri is too slow
+            #[test]
+            fn test_lots_of_isqrt() {
+                let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
+                for n in 0..=n_max {
+                    let isqrt: $T = n.isqrt();
+
+                    assert!(isqrt.pow(2) <= n);
+                    let (square, overflow) = (isqrt + 1).overflowing_pow(2);
+                    assert!(overflow || square > n);
+                }
+
+                for n in ($T::MAX - 127)..=$T::MAX {
+                    let isqrt: $T = n.isqrt();
+
+                    assert!(isqrt.pow(2) <= n);
+                    let (square, overflow) = (isqrt + 1).overflowing_pow(2);
+                    assert!(overflow || square > n);
+                }
+            }
+
             #[test]
             fn test_div_floor() {
                 let a: $T = 8;

library/core/tests/num/uint_macros.rs

@@ -206,6 +206,35 @@ fn test_pow() {
                 assert_eq!(r.saturating_pow(2), MAX);
             }
 
+            #[test]
+            fn test_isqrt() {
+                assert_eq!((0 as $T).isqrt(), 0 as $T);
+                assert_eq!((1 as $T).isqrt(), 1 as $T);
+                assert_eq!((2 as $T).isqrt(), 1 as $T);
+                assert_eq!((99 as $T).isqrt(), 9 as $T);
+                assert_eq!((100 as $T).isqrt(), 10 as $T);
+                assert_eq!($T::MAX.isqrt(), (1 << ($T::BITS / 2)) - 1);
+            }
+
+            #[cfg(not(miri))] // Miri is too slow
+            #[test]
+            fn test_lots_of_isqrt() {
+                let n_max: $T = (1024 * 1024).min($T::MAX as u128) as $T;
+                for n in 0..=n_max {
+                    let isqrt: $T = n.isqrt();
+
+                    assert!(isqrt.pow(2) <= n);
+                    assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
+                }
+
+                for n in ($T::MAX - 255)..=$T::MAX {
+                    let isqrt: $T = n.isqrt();
+
+                    assert!(isqrt.pow(2) <= n);
+                    assert!(isqrt + 1 == (1 as $T) << ($T::BITS / 2) || (isqrt + 1).pow(2) > n);
+                }
+            }
+
             #[test]
             fn test_div_floor() {
                 assert_eq!((8 as $T).div_floor(3), 2);

library/std/src/os/unix/process.rs

@@ -434,6 +434,20 @@ fn from(child_stdin: crate::process::ChildStdin) -> OwnedFd {
     }
 }
 
+/// Create a `ChildStdin` from the provided `OwnedFd`.
+///
+/// The provided file descriptor must point to a pipe
+/// with the `CLOEXEC` flag set.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedFd> for process::ChildStdin {
+    #[inline]
+    fn from(fd: OwnedFd) -> process::ChildStdin {
+        let fd = sys::fd::FileDesc::from_inner(fd);
+        let pipe = sys::pipe::AnonPipe::from_inner(fd);
+        process::ChildStdin::from_inner(pipe)
+    }
+}
+
 #[stable(feature = "io_safety", since = "1.63.0")]
 impl AsFd for crate::process::ChildStdout {
     #[inline]
@@ -450,6 +464,20 @@ fn from(child_stdout: crate::process::ChildStdout) -> OwnedFd {
     }
 }
 
+/// Create a `ChildStdout` from the provided `OwnedFd`.
+///
+/// The provided file descriptor must point to a pipe
+/// with the `CLOEXEC` flag set.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedFd> for process::ChildStdout {
+    #[inline]
+    fn from(fd: OwnedFd) -> process::ChildStdout {
+        let fd = sys::fd::FileDesc::from_inner(fd);
+        let pipe = sys::pipe::AnonPipe::from_inner(fd);
+        process::ChildStdout::from_inner(pipe)
+    }
+}
+
 #[stable(feature = "io_safety", since = "1.63.0")]
 impl AsFd for crate::process::ChildStderr {
     #[inline]
@@ -466,6 +494,20 @@ fn from(child_stderr: crate::process::ChildStderr) -> OwnedFd {
     }
 }
 
+/// Create a `ChildStderr` from the provided `OwnedFd`.
+///
+/// The provided file descriptor must point to a pipe
+/// with the `CLOEXEC` flag set.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedFd> for process::ChildStderr {
+    #[inline]
+    fn from(fd: OwnedFd) -> process::ChildStderr {
+        let fd = sys::fd::FileDesc::from_inner(fd);
+        let pipe = sys::pipe::AnonPipe::from_inner(fd);
+        process::ChildStderr::from_inner(pipe)
+    }
+}
+
 /// Returns the OS-assigned process identifier associated with this process's parent.
 #[must_use]
 #[stable(feature = "unix_ppid", since = "1.27.0")]

library/std/src/os/windows/io/socket.rs

@@ -116,7 +116,7 @@ pub fn try_clone_to_owned(&self) -> io::Result<OwnedSocket> {
         let mut info = unsafe { mem::zeroed::<sys::c::WSAPROTOCOL_INFOW>() };
         let result = unsafe {
             sys::c::WSADuplicateSocketW(
-                self.as_raw_socket(),
+                self.as_raw_socket() as sys::c::SOCKET,
                 sys::c::GetCurrentProcessId(),
                 &mut info,
             )
@@ -134,7 +134,7 @@ pub fn try_clone_to_owned(&self) -> io::Result<OwnedSocket> {
         };
 
         if socket != sys::c::INVALID_SOCKET {
-            unsafe { Ok(OwnedSocket::from_raw_socket(socket)) }
+            unsafe { Ok(OwnedSocket::from_raw_socket(socket as RawSocket)) }
         } else {
             let error = unsafe { sys::c::WSAGetLastError() };
 
@@ -158,7 +158,7 @@ pub fn try_clone_to_owned(&self) -> io::Result<OwnedSocket> {
             }
 
             unsafe {
-                let socket = OwnedSocket::from_raw_socket(socket);
+                let socket = OwnedSocket::from_raw_socket(socket as RawSocket);
                 socket.set_no_inherit()?;
                 Ok(socket)
             }
@@ -211,7 +211,7 @@ impl Drop for OwnedSocket {
     #[inline]
     fn drop(&mut self) {
         unsafe {
-            let _ = sys::c::closesocket(self.socket);
+            let _ = sys::c::closesocket(self.socket as sys::c::SOCKET);
         }
     }
 }

library/std/src/os/windows/process.rs

@@ -106,6 +106,45 @@ fn into_raw_handle(self) -> RawHandle {
     }
 }
 
+/// Create a `ChildStdin` from the provided `OwnedHandle`.
+///
+/// The provided handle must be asynchronous, as reading and
+/// writing from and to it is implemented using asynchronous APIs.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedHandle> for process::ChildStdin {
+    fn from(handle: OwnedHandle) -> process::ChildStdin {
+        let handle = sys::handle::Handle::from_inner(handle);
+        let pipe = sys::pipe::AnonPipe::from_inner(handle);
+        process::ChildStdin::from_inner(pipe)
+    }
+}
+
+/// Create a `ChildStdout` from the provided `OwnedHandle`.
+///
+/// The provided handle must be asynchronous, as reading and
+/// writing from and to it is implemented using asynchronous APIs.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedHandle> for process::ChildStdout {
+    fn from(handle: OwnedHandle) -> process::ChildStdout {
+        let handle = sys::handle::Handle::from_inner(handle);
+        let pipe = sys::pipe::AnonPipe::from_inner(handle);
+        process::ChildStdout::from_inner(pipe)
+    }
+}
+
+/// Create a `ChildStderr` from the provided `OwnedHandle`.
+///
+/// The provided handle must be asynchronous, as reading and
+/// writing from and to it is implemented using asynchronous APIs.
+#[stable(feature = "child_stream_from_fd", since = "CURRENT_RUSTC_VERSION")]
+impl From<OwnedHandle> for process::ChildStderr {
+    fn from(handle: OwnedHandle) -> process::ChildStderr {
+        let handle = sys::handle::Handle::from_inner(handle);
+        let pipe = sys::pipe::AnonPipe::from_inner(handle);
+        process::ChildStderr::from_inner(pipe)
+    }
+}
+
 /// Windows-specific extensions to [`process::ExitStatus`].
 ///
 /// This trait is sealed: it cannot be implemented outside the standard library.

library/std/src/process.rs

@@ -12,9 +12,9 @@
 //! use std::process::Command;
 //!
 //! let output = Command::new("echo")
-//!                      .arg("Hello world")
-//!                      .output()
-//!                      .expect("Failed to execute command");
+//!     .arg("Hello world")
+//!     .output()
+//!     .expect("Failed to execute command");
 //!
 //! assert_eq!(b"Hello world\n", output.stdout.as_slice());
 //! ```
@@ -154,12 +154,11 @@
 /// use std::process::Command;
 ///
 /// let mut child = Command::new("/bin/cat")
-///                         .arg("file.txt")
-///                         .spawn()
-///                         .expect("failed to execute child");
+///     .arg("file.txt")
+///     .spawn()
+///     .expect("failed to execute child");
 ///
-/// let ecode = child.wait()
-///                  .expect("failed to wait on child");
+/// let ecode = child.wait().expect("failed to wait on child");
 ///
 /// assert!(ecode.success());
 /// ```
@@ -481,15 +480,15 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 ///
 /// let output = if cfg!(target_os = "windows") {
 ///     Command::new("cmd")
-///             .args(["/C", "echo hello"])
-///             .output()
-///             .expect("failed to execute process")
+///         .args(["/C", "echo hello"])
+///         .output()
+///         .expect("failed to execute process")
 /// } else {
 ///     Command::new("sh")
-///             .arg("-c")
-///             .arg("echo hello")
-///             .output()
-///             .expect("failed to execute process")
+///         .arg("-c")
+///         .arg("echo hello")
+///         .output()
+///         .expect("failed to execute process")
 /// };
 ///
 /// let hello = output.stdout;
@@ -502,8 +501,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 /// use std::process::Command;
 ///
 /// let mut echo_hello = Command::new("sh");
-/// echo_hello.arg("-c")
-///           .arg("echo hello");
+/// echo_hello.arg("-c").arg("echo hello");
 /// let hello_1 = echo_hello.output().expect("failed to execute process");
 /// let hello_2 = echo_hello.output().expect("failed to execute process");
 /// ```
@@ -576,8 +574,8 @@ impl Command {
     /// use std::process::Command;
     ///
     /// Command::new("sh")
-    ///         .spawn()
-    ///         .expect("sh command failed to start");
+    ///     .spawn()
+    ///     .expect("sh command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
@@ -620,10 +618,10 @@ pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .arg("-l")
-    ///         .arg("-a")
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .arg("-l")
+    ///     .arg("-a")
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
@@ -650,9 +648,9 @@ pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .args(["-l", "-a"])
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .args(["-l", "-a"])
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn args<I, S>(&mut self, args: I) -> &mut Command
@@ -688,9 +686,9 @@ pub fn args<I, S>(&mut self, args: I) -> &mut Command
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .env("PATH", "/bin")
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .env("PATH", "/bin")
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
@@ -731,12 +729,12 @@ pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
     ///     ).collect();
     ///
     /// Command::new("printenv")
-    ///         .stdin(Stdio::null())
-    ///         .stdout(Stdio::inherit())
-    ///         .env_clear()
-    ///         .envs(&filtered_env)
-    ///         .spawn()
-    ///         .expect("printenv failed to start");
+    ///     .stdin(Stdio::null())
+    ///     .stdout(Stdio::inherit())
+    ///     .env_clear()
+    ///     .envs(&filtered_env)
+    ///     .spawn()
+    ///     .expect("printenv failed to start");
     /// ```
     #[stable(feature = "command_envs", since = "1.19.0")]
     pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command
@@ -772,9 +770,9 @@ pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .env_remove("PATH")
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .env_remove("PATH")
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
@@ -802,9 +800,9 @@ pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .env_clear()
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .env_clear()
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn env_clear(&mut self) -> &mut Command {
@@ -830,9 +828,9 @@ pub fn env_clear(&mut self) -> &mut Command {
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .current_dir("/bin")
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .current_dir("/bin")
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     ///
     /// [`canonicalize`]: crate::fs::canonicalize
@@ -861,9 +859,9 @@ pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command {
     /// use std::process::{Command, Stdio};
     ///
     /// Command::new("ls")
-    ///         .stdin(Stdio::null())
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .stdin(Stdio::null())
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
@@ -890,9 +888,9 @@ pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
     /// use std::process::{Command, Stdio};
     ///
     /// Command::new("ls")
-    ///         .stdout(Stdio::null())
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .stdout(Stdio::null())
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
@@ -919,9 +917,9 @@ pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
     /// use std::process::{Command, Stdio};
     ///
     /// Command::new("ls")
-    ///         .stderr(Stdio::null())
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .stderr(Stdio::null())
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
@@ -941,8 +939,8 @@ pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
     /// use std::process::Command;
     ///
     /// Command::new("ls")
-    ///         .spawn()
-    ///         .expect("ls command failed to start");
+    ///     .spawn()
+    ///     .expect("ls command failed to start");
     /// ```
     #[stable(feature = "process", since = "1.0.0")]
     pub fn spawn(&mut self) -> io::Result<Child> {
@@ -963,9 +961,9 @@ pub fn spawn(&mut self) -> io::Result<Child> {
     /// use std::process::Command;
     /// use std::io::{self, Write};
     /// let output = Command::new("/bin/cat")
-    ///                      .arg("file.txt")
-    ///                      .output()
-    ///                      .expect("failed to execute process");
+    ///     .arg("file.txt")
+    ///     .output()
+    ///     .expect("failed to execute process");
     ///
     /// println!("status: {}", output.status);
     /// io::stdout().write_all(&output.stdout).unwrap();
@@ -990,9 +988,9 @@ pub fn output(&mut self) -> io::Result<Output> {
     /// use std::process::Command;
     ///
     /// let status = Command::new("/bin/cat")
-    ///                      .arg("file.txt")
-    ///                      .status()
-    ///                      .expect("failed to execute process");
+    ///     .arg("file.txt")
+    ///     .status()
+    ///     .expect("failed to execute process");
     ///
     /// println!("process finished with: {status}");
     ///
@@ -1618,9 +1616,9 @@ impl ExitStatus {
     /// use std::process::Command;
     ///
     /// let status = Command::new("ls")
-    ///                      .arg("/dev/nonexistent")
-    ///                      .status()
-    ///                      .expect("ls could not be executed");
+    ///     .arg("/dev/nonexistent")
+    ///     .status()
+    ///     .expect("ls could not be executed");
     ///
     /// println!("ls: {status}");
     /// status.exit_ok().expect_err("/dev/nonexistent could be listed!");
@@ -1640,9 +1638,9 @@ pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
     /// use std::process::Command;
     ///
     /// let status = Command::new("mkdir")
-    ///                      .arg("projects")
-    ///                      .status()
-    ///                      .expect("failed to execute mkdir");
+    ///     .arg("projects")
+    ///     .status()
+    ///     .expect("failed to execute mkdir");
     ///
     /// if status.success() {
     ///     println!("'projects/' directory created");
@@ -1673,13 +1671,13 @@ pub fn success(&self) -> bool {
     /// use std::process::Command;
     ///
     /// let status = Command::new("mkdir")
-    ///                      .arg("projects")
-    ///                      .status()
-    ///                      .expect("failed to execute mkdir");
+    ///     .arg("projects")
+    ///     .status()
+    ///     .expect("failed to execute mkdir");
     ///
     /// match status.code() {
     ///     Some(code) => println!("Exited with status code: {code}"),
-    ///     None       => println!("Process terminated by signal")
+    ///     None => println!("Process terminated by signal")
     /// }
     /// ```
     #[must_use]
@@ -1809,9 +1807,9 @@ pub fn into_status(&self) -> ExitStatus {
 }
 
 #[unstable(feature = "exit_status_error", issue = "84908")]
-impl Into<ExitStatus> for ExitStatusError {
-    fn into(self) -> ExitStatus {
-        ExitStatus(self.0.into())
+impl From<ExitStatusError> for ExitStatus {
+    fn from(error: ExitStatusError) -> Self {
+        Self(error.0.into())
     }
 }
 

library/std/src/sys/unix/pipe.rs

@@ -3,7 +3,7 @@
 use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
 use crate::sys::fd::FileDesc;
 use crate::sys::{cvt, cvt_r};
-use crate::sys_common::IntoInner;
+use crate::sys_common::{FromInner, IntoInner};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Anonymous pipes
@@ -159,3 +159,9 @@ unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
         Self(FromRawFd::from_raw_fd(raw_fd))
     }
 }
+
+impl FromInner<FileDesc> for AnonPipe {
+    fn from_inner(fd: FileDesc) -> Self {
+        Self(fd)
+    }
+}

library/std/src/sys/windows/c.rs

@@ -46,10 +46,6 @@
 pub use LINGER as linger;
 pub use TIMEVAL as timeval;
 
-pub type CONDITION_VARIABLE = RTL_CONDITION_VARIABLE;
-pub type SRWLOCK = RTL_SRWLOCK;
-pub type INIT_ONCE = RTL_RUN_ONCE;
-
 pub const CONDITION_VARIABLE_INIT: CONDITION_VARIABLE = CONDITION_VARIABLE { Ptr: ptr::null_mut() };
 pub const SRWLOCK_INIT: SRWLOCK = SRWLOCK { Ptr: ptr::null_mut() };
 pub const INIT_ONCE_STATIC_INIT: INIT_ONCE = INIT_ONCE { Ptr: ptr::null_mut() };
@@ -224,7 +220,7 @@ pub struct in6_addr {
 ) -> BOOL {
     windows_sys::ReadFileEx(
         hFile.as_raw_handle(),
-        lpBuffer,
+        lpBuffer.cast::<u8>(),
         nNumberOfBytesToRead,
         lpOverlapped,
         lpCompletionRoutine,

library/std/src/sys/windows/c/windows_sys.lst

@@ -1,3 +1,6 @@
+--out windows_sys.rs
+--config flatten std
+--filter
 // tidy-alphabetical-start
 Windows.Wdk.Storage.FileSystem.FILE_COMPLETE_IF_OPLOCKED
 Windows.Wdk.Storage.FileSystem.FILE_CONTAINS_EXTENDED_CREATE_INFORMATION
@@ -2108,7 +2111,6 @@ Windows.Win32.Networking.WinSock.WSABASEERR
 Windows.Win32.Networking.WinSock.WSABUF
 Windows.Win32.Networking.WinSock.WSACleanup
 Windows.Win32.Networking.WinSock.WSADATA
-Windows.Win32.Networking.WinSock.WSADATA
 Windows.Win32.Networking.WinSock.WSADuplicateSocketW
 Windows.Win32.Networking.WinSock.WSAEACCES
 Windows.Win32.Networking.WinSock.WSAEADDRINUSE
@@ -2328,7 +2330,6 @@ Windows.Win32.Storage.FileSystem.FileStandardInfo
 Windows.Win32.Storage.FileSystem.FileStorageInfo
 Windows.Win32.Storage.FileSystem.FileStreamInfo
 Windows.Win32.Storage.FileSystem.FindClose
-Windows.Win32.Storage.FileSystem.FindFileHandle
 Windows.Win32.Storage.FileSystem.FindFirstFileW
 Windows.Win32.Storage.FileSystem.FindNextFileW
 Windows.Win32.Storage.FileSystem.FlushFileBuffers
@@ -2420,8 +2421,6 @@ Windows.Win32.System.Console.STD_OUTPUT_HANDLE
 Windows.Win32.System.Console.WriteConsoleW
 Windows.Win32.System.Diagnostics.Debug.ARM64_NT_NEON128
 Windows.Win32.System.Diagnostics.Debug.CONTEXT
-Windows.Win32.System.Diagnostics.Debug.CONTEXT
-Windows.Win32.System.Diagnostics.Debug.CONTEXT
 Windows.Win32.System.Diagnostics.Debug.EXCEPTION_RECORD
 Windows.Win32.System.Diagnostics.Debug.FACILITY_CODE
 Windows.Win32.System.Diagnostics.Debug.FACILITY_NT_BIT
@@ -2435,7 +2434,6 @@ Windows.Win32.System.Diagnostics.Debug.FORMAT_MESSAGE_OPTIONS
 Windows.Win32.System.Diagnostics.Debug.FormatMessageW
 Windows.Win32.System.Diagnostics.Debug.M128A
 Windows.Win32.System.Diagnostics.Debug.XSAVE_FORMAT
-Windows.Win32.System.Diagnostics.Debug.XSAVE_FORMAT
 Windows.Win32.System.Environment.FreeEnvironmentStringsW
 Windows.Win32.System.Environment.GetCommandLineW
 Windows.Win32.System.Environment.GetCurrentDirectoryW
@@ -2456,7 +2454,6 @@ Windows.Win32.System.Kernel.ExceptionContinueExecution
 Windows.Win32.System.Kernel.ExceptionContinueSearch
 Windows.Win32.System.Kernel.ExceptionNestedException
 Windows.Win32.System.Kernel.FLOATING_SAVE_AREA
-Windows.Win32.System.Kernel.FLOATING_SAVE_AREA
 Windows.Win32.System.Kernel.OBJ_DONT_REPARSE
 Windows.Win32.System.LibraryLoader.GetModuleFileNameW
 Windows.Win32.System.LibraryLoader.GetModuleHandleA
@@ -2482,6 +2479,7 @@ Windows.Win32.System.SystemInformation.GetSystemTimeAsFileTime
 Windows.Win32.System.SystemInformation.GetWindowsDirectoryW
 Windows.Win32.System.SystemInformation.PROCESSOR_ARCHITECTURE
 Windows.Win32.System.SystemInformation.SYSTEM_INFO
+Windows.Win32.System.SystemServices.ALL_PROCESSOR_GROUPS
 Windows.Win32.System.SystemServices.DLL_PROCESS_DETACH
 Windows.Win32.System.SystemServices.DLL_THREAD_DETACH
 Windows.Win32.System.SystemServices.EXCEPTION_MAXIMUM_PARAMETERS
@@ -2514,6 +2512,7 @@ Windows.Win32.System.Threading.DeleteProcThreadAttributeList
 Windows.Win32.System.Threading.DETACHED_PROCESS
 Windows.Win32.System.Threading.ExitProcess
 Windows.Win32.System.Threading.EXTENDED_STARTUPINFO_PRESENT
+Windows.Win32.System.Threading.GetActiveProcessorCount
 Windows.Win32.System.Threading.GetCurrentProcess
 Windows.Win32.System.Threading.GetCurrentProcessId
 Windows.Win32.System.Threading.GetCurrentThread
@@ -2542,9 +2541,6 @@ Windows.Win32.System.Threading.PROFILE_USER
 Windows.Win32.System.Threading.REALTIME_PRIORITY_CLASS
 Windows.Win32.System.Threading.ReleaseSRWLockExclusive
 Windows.Win32.System.Threading.ReleaseSRWLockShared
-Windows.Win32.System.Threading.RTL_CONDITION_VARIABLE
-Windows.Win32.System.Threading.RTL_RUN_ONCE
-Windows.Win32.System.Threading.RTL_SRWLOCK
 Windows.Win32.System.Threading.SetThreadStackGuarantee
 Windows.Win32.System.Threading.Sleep
 Windows.Win32.System.Threading.SleepConditionVariableSRW
@@ -2584,8 +2580,6 @@ Windows.Win32.System.Threading.WaitForMultipleObjects
 Windows.Win32.System.Threading.WaitForSingleObject
 Windows.Win32.System.Threading.WakeAllConditionVariable
 Windows.Win32.System.Threading.WakeConditionVariable
-Windows.Win32.System.WindowsProgramming.IO_STATUS_BLOCK
-Windows.Win32.System.WindowsProgramming.OBJECT_ATTRIBUTES
 Windows.Win32.System.WindowsProgramming.PROGRESS_CONTINUE
 Windows.Win32.UI.Shell.GetUserProfileDirectoryW
 // tidy-alphabetical-end

library/std/src/sys/windows/c/windows_sys.rs

@@ -4,7 +4,7 @@
 // regenerate the bindings.
 //
 // ignore-tidy-filelength
-// Bindings generated by `windows-bindgen` 0.49.0
+// Bindings generated by `windows-bindgen` 0.51.1
 
 #![allow(non_snake_case, non_upper_case_globals, non_camel_case_types, dead_code, clippy::all)]
 #[link(name = "advapi32")]
@@ -32,11 +32,11 @@ pub fn BCryptGenRandom(
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn AcquireSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> ();
+    pub fn AcquireSRWLockExclusive(srwlock: *mut SRWLOCK) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn AcquireSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> ();
+    pub fn AcquireSRWLockShared(srwlock: *mut SRWLOCK) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
@@ -189,18 +189,15 @@ pub fn DuplicateHandle(
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn FindClose(hfindfile: FindFileHandle) -> BOOL;
+    pub fn FindClose(hfindfile: HANDLE) -> BOOL;
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn FindFirstFileW(
-        lpfilename: PCWSTR,
-        lpfindfiledata: *mut WIN32_FIND_DATAW,
-    ) -> FindFileHandle;
+    pub fn FindFirstFileW(lpfilename: PCWSTR, lpfindfiledata: *mut WIN32_FIND_DATAW) -> HANDLE;
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn FindNextFileW(hfindfile: FindFileHandle, lpfindfiledata: *mut WIN32_FIND_DATAW) -> BOOL;
+    pub fn FindNextFileW(hfindfile: HANDLE, lpfindfiledata: *mut WIN32_FIND_DATAW) -> BOOL;
 }
 #[link(name = "kernel32")]
 extern "system" {
@@ -223,6 +220,10 @@ pub fn FormatMessageW(
     pub fn FreeEnvironmentStringsW(penv: PCWSTR) -> BOOL;
 }
 #[link(name = "kernel32")]
+extern "system" {
+    pub fn GetActiveProcessorCount(groupnumber: u16) -> u32;
+}
+#[link(name = "kernel32")]
 extern "system" {
     pub fn GetCommandLineW() -> PCWSTR;
 }
@@ -360,7 +361,7 @@ pub fn GetOverlappedResult(
 #[link(name = "kernel32")]
 extern "system" {
     pub fn InitOnceBeginInitialize(
-        lpinitonce: *mut RTL_RUN_ONCE,
+        lpinitonce: *mut INIT_ONCE,
         dwflags: u32,
         fpending: *mut BOOL,
         lpcontext: *mut *mut ::core::ffi::c_void,
@@ -369,7 +370,7 @@ pub fn InitOnceBeginInitialize(
 #[link(name = "kernel32")]
 extern "system" {
     pub fn InitOnceComplete(
-        lpinitonce: *mut RTL_RUN_ONCE,
+        lpinitonce: *mut INIT_ONCE,
         dwflags: u32,
         lpcontext: *const ::core::ffi::c_void,
     ) -> BOOL;
@@ -424,7 +425,7 @@ pub fn ReadConsoleW(
 extern "system" {
     pub fn ReadFile(
         hfile: HANDLE,
-        lpbuffer: *mut ::core::ffi::c_void,
+        lpbuffer: *mut u8,
         nnumberofbytestoread: u32,
         lpnumberofbytesread: *mut u32,
         lpoverlapped: *mut OVERLAPPED,
@@ -434,7 +435,7 @@ pub fn ReadFile(
 extern "system" {
     pub fn ReadFileEx(
         hfile: HANDLE,
-        lpbuffer: *mut ::core::ffi::c_void,
+        lpbuffer: *mut u8,
         nnumberofbytestoread: u32,
         lpoverlapped: *mut OVERLAPPED,
         lpcompletionroutine: LPOVERLAPPED_COMPLETION_ROUTINE,
@@ -442,11 +443,11 @@ pub fn ReadFileEx(
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn ReleaseSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> ();
+    pub fn ReleaseSRWLockExclusive(srwlock: *mut SRWLOCK) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn ReleaseSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> ();
+    pub fn ReleaseSRWLockShared(srwlock: *mut SRWLOCK) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
@@ -513,8 +514,8 @@ pub fn SetFileTime(
 #[link(name = "kernel32")]
 extern "system" {
     pub fn SleepConditionVariableSRW(
-        conditionvariable: *mut RTL_CONDITION_VARIABLE,
-        srwlock: *mut RTL_SRWLOCK,
+        conditionvariable: *mut CONDITION_VARIABLE,
+        srwlock: *mut SRWLOCK,
         dwmilliseconds: u32,
         flags: u32,
     ) -> BOOL;
@@ -549,11 +550,11 @@ pub fn SleepConditionVariableSRW(
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn TryAcquireSRWLockExclusive(srwlock: *mut RTL_SRWLOCK) -> BOOLEAN;
+    pub fn TryAcquireSRWLockExclusive(srwlock: *mut SRWLOCK) -> BOOLEAN;
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn TryAcquireSRWLockShared(srwlock: *mut RTL_SRWLOCK) -> BOOLEAN;
+    pub fn TryAcquireSRWLockShared(srwlock: *mut SRWLOCK) -> BOOLEAN;
 }
 #[link(name = "kernel32")]
 extern "system" {
@@ -574,19 +575,19 @@ pub fn WaitForMultipleObjects(
         lphandles: *const HANDLE,
         bwaitall: BOOL,
         dwmilliseconds: u32,
-    ) -> WIN32_ERROR;
+    ) -> WAIT_EVENT;
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn WaitForSingleObject(hhandle: HANDLE, dwmilliseconds: u32) -> WIN32_ERROR;
+    pub fn WaitForSingleObject(hhandle: HANDLE, dwmilliseconds: u32) -> WAIT_EVENT;
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn WakeAllConditionVariable(conditionvariable: *mut RTL_CONDITION_VARIABLE) -> ();
+    pub fn WakeAllConditionVariable(conditionvariable: *mut CONDITION_VARIABLE) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
-    pub fn WakeConditionVariable(conditionvariable: *mut RTL_CONDITION_VARIABLE) -> ();
+    pub fn WakeConditionVariable(conditionvariable: *mut CONDITION_VARIABLE) -> ();
 }
 #[link(name = "kernel32")]
 extern "system" {
@@ -847,6 +848,7 @@ fn clone(&self) -> Self {
 pub const AF_INET: ADDRESS_FAMILY = 2u16;
 pub const AF_INET6: ADDRESS_FAMILY = 23u16;
 pub const AF_UNSPEC: ADDRESS_FAMILY = 0u16;
+pub const ALL_PROCESSOR_GROUPS: u32 = 65535u32;
 #[repr(C)]
 pub union ARM64_NT_NEON128 {
     pub Anonymous: ARM64_NT_NEON128_0,
@@ -899,7 +901,17 @@ fn clone(&self) -> Self {
 }
 pub const CALLBACK_CHUNK_FINISHED: LPPROGRESS_ROUTINE_CALLBACK_REASON = 0u32;
 pub const CALLBACK_STREAM_SWITCH: LPPROGRESS_ROUTINE_CALLBACK_REASON = 1u32;
-pub type COMPARESTRING_RESULT = u32;
+pub type COMPARESTRING_RESULT = i32;
+#[repr(C)]
+pub struct CONDITION_VARIABLE {
+    pub Ptr: *mut ::core::ffi::c_void,
+}
+impl ::core::marker::Copy for CONDITION_VARIABLE {}
+impl ::core::clone::Clone for CONDITION_VARIABLE {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
 pub type CONSOLE_MODE = u32;
 #[repr(C)]
 pub struct CONSOLE_READCONSOLE_CONTROL {
@@ -917,7 +929,7 @@ fn clone(&self) -> Self {
 #[repr(C)]
 #[cfg(target_arch = "aarch64")]
 pub struct CONTEXT {
-    pub ContextFlags: u32,
+    pub ContextFlags: CONTEXT_FLAGS,
     pub Cpsr: u32,
     pub Anonymous: CONTEXT_0,
     pub Sp: u64,
@@ -1004,7 +1016,7 @@ pub struct CONTEXT {
     pub P4Home: u64,
     pub P5Home: u64,
     pub P6Home: u64,
-    pub ContextFlags: u32,
+    pub ContextFlags: CONTEXT_FLAGS,
     pub MxCsr: u32,
     pub SegCs: u16,
     pub SegDs: u16,
@@ -1100,7 +1112,7 @@ fn clone(&self) -> Self {
 #[repr(C)]
 #[cfg(target_arch = "x86")]
 pub struct CONTEXT {
-    pub ContextFlags: u32,
+    pub ContextFlags: CONTEXT_FLAGS,
     pub Dr0: u32,
     pub Dr1: u32,
     pub Dr2: u32,
@@ -1134,6 +1146,7 @@ fn clone(&self) -> Self {
         *self
     }
 }
+pub type CONTEXT_FLAGS = u32;
 pub const CP_UTF8: u32 = 65001u32;
 pub const CREATE_ALWAYS: FILE_CREATION_DISPOSITION = 2u32;
 pub const CREATE_BREAKAWAY_FROM_JOB: PROCESS_CREATION_FLAGS = 16777216u32;
@@ -1151,9 +1164,9 @@ fn clone(&self) -> Self {
 pub const CREATE_SHARED_WOW_VDM: PROCESS_CREATION_FLAGS = 4096u32;
 pub const CREATE_SUSPENDED: PROCESS_CREATION_FLAGS = 4u32;
 pub const CREATE_UNICODE_ENVIRONMENT: PROCESS_CREATION_FLAGS = 1024u32;
-pub const CSTR_EQUAL: COMPARESTRING_RESULT = 2u32;
-pub const CSTR_GREATER_THAN: COMPARESTRING_RESULT = 3u32;
-pub const CSTR_LESS_THAN: COMPARESTRING_RESULT = 1u32;
+pub const CSTR_EQUAL: COMPARESTRING_RESULT = 2i32;
+pub const CSTR_GREATER_THAN: COMPARESTRING_RESULT = 3i32;
+pub const CSTR_LESS_THAN: COMPARESTRING_RESULT = 1i32;
 pub const DEBUG_ONLY_THIS_PROCESS: PROCESS_CREATION_FLAGS = 2u32;
 pub const DEBUG_PROCESS: PROCESS_CREATION_FLAGS = 1u32;
 pub const DELETE: FILE_ACCESS_RIGHTS = 65536u32;
@@ -3369,7 +3382,6 @@ fn clone(&self) -> Self {
 pub const FileStandardInfo: FILE_INFO_BY_HANDLE_CLASS = 1i32;
 pub const FileStorageInfo: FILE_INFO_BY_HANDLE_CLASS = 16i32;
 pub const FileStreamInfo: FILE_INFO_BY_HANDLE_CLASS = 7i32;
-pub type FindFileHandle = *mut ::core::ffi::c_void;
 pub type GENERIC_ACCESS_RIGHTS = u32;
 pub const GENERIC_ALL: GENERIC_ACCESS_RIGHTS = 268435456u32;
 pub const GENERIC_EXECUTE: GENERIC_ACCESS_RIGHTS = 536870912u32;
@@ -3383,6 +3395,12 @@ pub struct GUID {
     pub data3: u16,
     pub data4: [u8; 8],
 }
+impl ::core::marker::Copy for GUID {}
+impl ::core::clone::Clone for GUID {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
 impl GUID {
     pub const fn from_u128(uuid: u128) -> Self {
         Self {
@@ -3393,12 +3411,6 @@ pub const fn from_u128(uuid: u128) -> Self {
         }
     }
 }
-impl ::core::marker::Copy for GUID {}
-impl ::core::clone::Clone for GUID {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
 pub type HANDLE = *mut ::core::ffi::c_void;
 pub type HANDLE_FLAGS = u32;
 pub const HANDLE_FLAG_INHERIT: HANDLE_FLAGS = 1u32;
@@ -3431,6 +3443,16 @@ fn clone(&self) -> Self {
 pub const INFINITE: u32 = 4294967295u32;
 pub const INHERIT_CALLER_PRIORITY: PROCESS_CREATION_FLAGS = 131072u32;
 pub const INHERIT_PARENT_AFFINITY: PROCESS_CREATION_FLAGS = 65536u32;
+#[repr(C)]
+pub union INIT_ONCE {
+    pub Ptr: *mut ::core::ffi::c_void,
+}
+impl ::core::marker::Copy for INIT_ONCE {}
+impl ::core::clone::Clone for INIT_ONCE {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
 pub const INIT_ONCE_INIT_FAILED: u32 = 4u32;
 pub const INVALID_FILE_ATTRIBUTES: u32 = 4294967295u32;
 pub const INVALID_HANDLE_VALUE: HANDLE = ::core::ptr::invalid_mut(-1i32 as _);
@@ -3659,10 +3681,10 @@ fn clone(&self) -> Self {
 pub struct OBJECT_ATTRIBUTES {
     pub Length: u32,
     pub RootDirectory: HANDLE,
-    pub ObjectName: *mut UNICODE_STRING,
+    pub ObjectName: *const UNICODE_STRING,
     pub Attributes: u32,
-    pub SecurityDescriptor: *mut ::core::ffi::c_void,
-    pub SecurityQualityOfService: *mut ::core::ffi::c_void,
+    pub SecurityDescriptor: *const ::core::ffi::c_void,
+    pub SecurityQualityOfService: *const ::core::ffi::c_void,
 }
 impl ::core::marker::Copy for OBJECT_ATTRIBUTES {}
 impl ::core::clone::Clone for OBJECT_ATTRIBUTES {
@@ -3712,8 +3734,8 @@ fn clone(&self) -> Self {
 pub type PCWSTR = *const u16;
 pub type PIO_APC_ROUTINE = ::core::option::Option<
     unsafe extern "system" fn(
-        apccontext: *const ::core::ffi::c_void,
-        iostatusblock: *const IO_STATUS_BLOCK,
+        apccontext: *mut ::core::ffi::c_void,
+        iostatusblock: *mut IO_STATUS_BLOCK,
         reserved: u32,
     ) -> (),
 >;
@@ -3755,36 +3777,6 @@ fn clone(&self) -> Self {
 pub type PWSTR = *mut u16;
 pub const READ_CONTROL: FILE_ACCESS_RIGHTS = 131072u32;
 pub const REALTIME_PRIORITY_CLASS: PROCESS_CREATION_FLAGS = 256u32;
-#[repr(C)]
-pub struct RTL_CONDITION_VARIABLE {
-    pub Ptr: *mut ::core::ffi::c_void,
-}
-impl ::core::marker::Copy for RTL_CONDITION_VARIABLE {}
-impl ::core::clone::Clone for RTL_CONDITION_VARIABLE {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-#[repr(C)]
-pub union RTL_RUN_ONCE {
-    pub Ptr: *mut ::core::ffi::c_void,
-}
-impl ::core::marker::Copy for RTL_RUN_ONCE {}
-impl ::core::clone::Clone for RTL_RUN_ONCE {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
-#[repr(C)]
-pub struct RTL_SRWLOCK {
-    pub Ptr: *mut ::core::ffi::c_void,
-}
-impl ::core::marker::Copy for RTL_SRWLOCK {}
-impl ::core::clone::Clone for RTL_SRWLOCK {
-    fn clone(&self) -> Self {
-        *self
-    }
-}
 pub const SD_BOTH: WINSOCK_SHUTDOWN_HOW = 2i32;
 pub const SD_RECEIVE: WINSOCK_SHUTDOWN_HOW = 0i32;
 pub const SD_SEND: WINSOCK_SHUTDOWN_HOW = 1i32;
@@ -3821,10 +3813,7 @@ fn clone(&self) -> Self {
         *self
     }
 }
-#[cfg(target_pointer_width = "32")]
-pub type SOCKET = u32;
-#[cfg(target_pointer_width = "64")]
-pub type SOCKET = u64;
+pub type SOCKET = usize;
 pub const SOCKET_ERROR: i32 = -1i32;
 pub const SOCK_DGRAM: WINSOCK_SOCKET_TYPE = 2i32;
 pub const SOCK_RAW: WINSOCK_SOCKET_TYPE = 3i32;
@@ -3838,6 +3827,16 @@ fn clone(&self) -> Self {
 pub const SO_RCVTIMEO: i32 = 4102i32;
 pub const SO_SNDTIMEO: i32 = 4101i32;
 pub const SPECIFIC_RIGHTS_ALL: FILE_ACCESS_RIGHTS = 65535u32;
+#[repr(C)]
+pub struct SRWLOCK {
+    pub Ptr: *mut ::core::ffi::c_void,
+}
+impl ::core::marker::Copy for SRWLOCK {}
+impl ::core::clone::Clone for SRWLOCK {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
 pub const STACK_SIZE_PARAM_IS_A_RESERVATION: THREAD_CREATION_FLAGS = 65536u32;
 pub const STANDARD_RIGHTS_ALL: FILE_ACCESS_RIGHTS = 2031616u32;
 pub const STANDARD_RIGHTS_EXECUTE: FILE_ACCESS_RIGHTS = 131072u32;
@@ -4008,12 +4007,13 @@ fn clone(&self) -> Self {
 pub const VOLUME_NAME_DOS: GETFINALPATHNAMEBYHANDLE_FLAGS = 0u32;
 pub const VOLUME_NAME_GUID: GETFINALPATHNAMEBYHANDLE_FLAGS = 1u32;
 pub const VOLUME_NAME_NONE: GETFINALPATHNAMEBYHANDLE_FLAGS = 4u32;
-pub const WAIT_ABANDONED: WIN32_ERROR = 128u32;
-pub const WAIT_ABANDONED_0: WIN32_ERROR = 128u32;
-pub const WAIT_FAILED: WIN32_ERROR = 4294967295u32;
-pub const WAIT_IO_COMPLETION: WIN32_ERROR = 192u32;
-pub const WAIT_OBJECT_0: WIN32_ERROR = 0u32;
-pub const WAIT_TIMEOUT: WIN32_ERROR = 258u32;
+pub const WAIT_ABANDONED: WAIT_EVENT = 128u32;
+pub const WAIT_ABANDONED_0: WAIT_EVENT = 128u32;
+pub type WAIT_EVENT = u32;
+pub const WAIT_FAILED: WAIT_EVENT = 4294967295u32;
+pub const WAIT_IO_COMPLETION: WAIT_EVENT = 192u32;
+pub const WAIT_OBJECT_0: WAIT_EVENT = 0u32;
+pub const WAIT_TIMEOUT: WAIT_EVENT = 258u32;
 pub const WC_ERR_INVALID_CHARS: u32 = 128u32;
 pub type WIN32_ERROR = u32;
 #[repr(C)]

library/std/src/sys/windows/handle.rs

@@ -143,13 +143,8 @@ pub unsafe fn read_overlapped(
     ) -> io::Result<Option<usize>> {
         let len = cmp::min(buf.len(), <c::DWORD>::MAX as usize) as c::DWORD;
         let mut amt = 0;
-        let res = cvt(c::ReadFile(
-            self.as_raw_handle(),
-            buf.as_ptr() as c::LPVOID,
-            len,
-            &mut amt,
-            overlapped,
-        ));
+        let res =
+            cvt(c::ReadFile(self.as_raw_handle(), buf.as_mut_ptr(), len, &mut amt, overlapped));
         match res {
             Ok(_) => Ok(Some(amt as usize)),
             Err(e) => {

library/std/src/sys/windows/net.rs

@@ -117,7 +117,7 @@ pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> {
         };
 
         if socket != c::INVALID_SOCKET {
-            unsafe { Ok(Self::from_raw_socket(socket)) }
+            unsafe { Ok(Self::from_raw(socket)) }
         } else {
             let error = unsafe { c::WSAGetLastError() };
 
@@ -133,7 +133,7 @@ pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> {
             }
 
             unsafe {
-                let socket = Self::from_raw_socket(socket);
+                let socket = Self::from_raw(socket);
                 socket.0.set_no_inherit()?;
                 Ok(socket)
             }
@@ -144,7 +144,7 @@ pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Resul
         self.set_nonblocking(true)?;
         let result = {
             let (addr, len) = addr.into_inner();
-            let result = unsafe { c::connect(self.as_raw_socket(), addr.as_ptr(), len) };
+            let result = unsafe { c::connect(self.as_raw(), addr.as_ptr(), len) };
             cvt(result).map(drop)
         };
         self.set_nonblocking(false)?;
@@ -170,7 +170,7 @@ pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Resul
                 let fds = {
                     let mut fds = unsafe { mem::zeroed::<c::fd_set>() };
                     fds.fd_count = 1;
-                    fds.fd_array[0] = self.as_raw_socket();
+                    fds.fd_array[0] = self.as_raw();
                     fds
                 };
 
@@ -202,11 +202,11 @@ pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Resul
     }
 
     pub fn accept(&self, storage: *mut c::SOCKADDR, len: *mut c_int) -> io::Result<Socket> {
-        let socket = unsafe { c::accept(self.as_raw_socket(), storage, len) };
+        let socket = unsafe { c::accept(self.as_raw(), storage, len) };
 
         match socket {
             c::INVALID_SOCKET => Err(last_error()),
-            _ => unsafe { Ok(Self::from_raw_socket(socket)) },
+            _ => unsafe { Ok(Self::from_raw(socket)) },
         }
     }
 
@@ -218,9 +218,8 @@ fn recv_with_flags(&self, mut buf: BorrowedCursor<'_>, flags: c_int) -> io::Resu
         // On unix when a socket is shut down all further reads return 0, so we
         // do the same on windows to map a shut down socket to returning EOF.
         let length = cmp::min(buf.capacity(), i32::MAX as usize) as i32;
-        let result = unsafe {
-            c::recv(self.as_raw_socket(), buf.as_mut().as_mut_ptr() as *mut _, length, flags)
-        };
+        let result =
+            unsafe { c::recv(self.as_raw(), buf.as_mut().as_mut_ptr() as *mut _, length, flags) };
 
         match result {
             c::SOCKET_ERROR => {
@@ -257,7 +256,7 @@ pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
         let mut flags = 0;
         let result = unsafe {
             c::WSARecv(
-                self.as_raw_socket(),
+                self.as_raw(),
                 bufs.as_mut_ptr() as *mut c::WSABUF,
                 length,
                 &mut nread,
@@ -305,7 +304,7 @@ fn recv_from_with_flags(
         // do the same on windows to map a shut down socket to returning EOF.
         let result = unsafe {
             c::recvfrom(
-                self.as_raw_socket(),
+                self.as_raw(),
                 buf.as_mut_ptr() as *mut _,
                 length,
                 flags,
@@ -341,7 +340,7 @@ pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
         let mut nwritten = 0;
         let result = unsafe {
             c::WSASend(
-                self.as_raw_socket(),
+                self.as_raw(),
                 bufs.as_ptr() as *const c::WSABUF as *mut _,
                 length,
                 &mut nwritten,
@@ -392,14 +391,14 @@ pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
             Shutdown::Read => c::SD_RECEIVE,
             Shutdown::Both => c::SD_BOTH,
         };
-        let result = unsafe { c::shutdown(self.as_raw_socket(), how) };
+        let result = unsafe { c::shutdown(self.as_raw(), how) };
         cvt(result).map(drop)
     }
 
     pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
         let mut nonblocking = nonblocking as c_ulong;
         let result =
-            unsafe { c::ioctlsocket(self.as_raw_socket(), c::FIONBIO as c_int, &mut nonblocking) };
+            unsafe { c::ioctlsocket(self.as_raw(), c::FIONBIO as c_int, &mut nonblocking) };
         cvt(result).map(drop)
     }
 
@@ -433,8 +432,15 @@ pub fn take_error(&self) -> io::Result<Option<io::Error>> {
     }
 
     // This is used by sys_common code to abstract over Windows and Unix.
-    pub fn as_raw(&self) -> RawSocket {
-        self.as_inner().as_raw_socket()
+    pub fn as_raw(&self) -> c::SOCKET {
+        debug_assert_eq!(mem::size_of::<c::SOCKET>(), mem::size_of::<RawSocket>());
+        debug_assert_eq!(mem::align_of::<c::SOCKET>(), mem::align_of::<RawSocket>());
+        self.as_inner().as_raw_socket() as c::SOCKET
+    }
+    pub unsafe fn from_raw(raw: c::SOCKET) -> Self {
+        debug_assert_eq!(mem::size_of::<c::SOCKET>(), mem::size_of::<RawSocket>());
+        debug_assert_eq!(mem::align_of::<c::SOCKET>(), mem::align_of::<RawSocket>());
+        Self::from_raw_socket(raw as RawSocket)
     }
 }
 

library/std/src/sys/windows/pipe.rs

@@ -12,7 +12,7 @@
 use crate::sys::fs::{File, OpenOptions};
 use crate::sys::handle::Handle;
 use crate::sys::hashmap_random_keys;
-use crate::sys_common::IntoInner;
+use crate::sys_common::{FromInner, IntoInner};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Anonymous pipes
@@ -28,6 +28,12 @@ fn into_inner(self) -> Handle {
     }
 }
 
+impl FromInner<Handle> for AnonPipe {
+    fn from_inner(inner: Handle) -> AnonPipe {
+        Self { inner }
+    }
+}
+
 pub struct Pipes {
     pub ours: AnonPipe,
     pub theirs: AnonPipe,

src/bootstrap/bootstrap.py

@@ -41,6 +41,10 @@ def get_cpus():
         return 1
 
 
+def eprint(*args, **kwargs):
+    kwargs["file"] = sys.stderr
+    print(*args, **kwargs)
+
 
 def get(base, url, path, checksums, verbose=False):
     with tempfile.NamedTemporaryFile(delete=False) as temp_file:
@@ -57,23 +61,23 @@ def get(base, url, path, checksums, verbose=False):
         if os.path.exists(path):
             if verify(path, sha256, False):
                 if verbose:
-                    print("using already-download file", path, file=sys.stderr)
+                    eprint("using already-download file", path)
                 return
             else:
                 if verbose:
-                    print("ignoring already-download file",
-                        path, "due to failed verification", file=sys.stderr)
+                    eprint("ignoring already-download file",
+                        path, "due to failed verification")
                 os.unlink(path)
         download(temp_path, "{}/{}".format(base, url), True, verbose)
         if not verify(temp_path, sha256, verbose):
             raise RuntimeError("failed verification")
         if verbose:
-            print("moving {} to {}".format(temp_path, path), file=sys.stderr)
+            eprint("moving {} to {}".format(temp_path, path))
         shutil.move(temp_path, path)
     finally:
         if os.path.isfile(temp_path):
             if verbose:
-                print("removing", temp_path, file=sys.stderr)
+                eprint("removing", temp_path)
             os.unlink(temp_path)
 
 
@@ -83,7 +87,7 @@ def download(path, url, probably_big, verbose):
             _download(path, url, probably_big, verbose, True)
             return
         except RuntimeError:
-            print("\nspurious failure, trying again", file=sys.stderr)
+            eprint("\nspurious failure, trying again")
     _download(path, url, probably_big, verbose, False)
 
 
@@ -94,7 +98,7 @@ def _download(path, url, probably_big, verbose, exception):
     #  - If we are on win32 fallback to powershell
     #  - Otherwise raise the error if appropriate
     if probably_big or verbose:
-        print("downloading {}".format(url), file=sys.stderr)
+        eprint("downloading {}".format(url))
 
     try:
         if (probably_big or verbose) and "GITHUB_ACTIONS" not in os.environ:
@@ -129,20 +133,20 @@ def _download(path, url, probably_big, verbose, exception):
 def verify(path, expected, verbose):
     """Check if the sha256 sum of the given path is valid"""
     if verbose:
-        print("verifying", path, file=sys.stderr)
+        eprint("verifying", path)
     with open(path, "rb") as source:
         found = hashlib.sha256(source.read()).hexdigest()
     verified = found == expected
     if not verified:
-        print("invalid checksum:\n"
+        eprint("invalid checksum:\n"
               "    found:    {}\n"
-              "    expected: {}".format(found, expected), file=sys.stderr)
+              "    expected: {}".format(found, expected))
     return verified
 
 
 def unpack(tarball, tarball_suffix, dst, verbose=False, match=None):
     """Unpack the given tarball file"""
-    print("extracting", tarball, file=sys.stderr)
+    eprint("extracting", tarball)
     fname = os.path.basename(tarball).replace(tarball_suffix, "")
     with contextlib.closing(tarfile.open(tarball)) as tar:
         for member in tar.getnames():
@@ -155,7 +159,7 @@ def unpack(tarball, tarball_suffix, dst, verbose=False, match=None):
 
             dst_path = os.path.join(dst, name)
             if verbose:
-                print("  extracting", member, file=sys.stderr)
+                eprint("  extracting", member)
             tar.extract(member, dst)
             src_path = os.path.join(dst, member)
             if os.path.isdir(src_path) and os.path.exists(dst_path):
@@ -167,7 +171,7 @@ def unpack(tarball, tarball_suffix, dst, verbose=False, match=None):
 def run(args, verbose=False, exception=False, is_bootstrap=False, **kwargs):
     """Run a child program in a new process"""
     if verbose:
-        print("running: " + ' '.join(args), file=sys.stderr)
+        eprint("running: " + ' '.join(args))
     sys.stdout.flush()
     # Ensure that the .exe is used on Windows just in case a Linux ELF has been
     # compiled in the same directory.
@@ -207,8 +211,8 @@ def require(cmd, exit=True, exception=False):
         if exception:
             raise
         elif exit:
-            print("error: unable to run `{}`: {}".format(' '.join(cmd), exc), file=sys.stderr)
-            print("Please make sure it's installed and in the path.", file=sys.stderr)
+            eprint("error: unable to run `{}`: {}".format(' '.join(cmd), exc))
+            eprint("Please make sure it's installed and in the path.")
             sys.exit(1)
         return None
 
@@ -239,14 +243,12 @@ def default_build_triple(verbose):
             host = next(x for x in version.split('\n') if x.startswith("host: "))
             triple = host.split("host: ")[1]
             if verbose:
-                print("detected default triple {} from pre-installed rustc".format(triple),
-                    file=sys.stderr)
+                eprint("detected default triple {} from pre-installed rustc".format(triple))
             return triple
         except Exception as e:
             if verbose:
-                print("pre-installed rustc not detected: {}".format(e),
-                    file=sys.stderr)
-                print("falling back to auto-detect", file=sys.stderr)
+                eprint("pre-installed rustc not detected: {}".format(e))
+                eprint("falling back to auto-detect")
 
     required = not platform_is_win32()
     uname = require(["uname", "-smp"], exit=required)
@@ -672,15 +674,14 @@ class RustBuild(object):
             if not is_nixos:
                 in_nix_shell = os.getenv('IN_NIX_SHELL')
                 if in_nix_shell:
-                    print("The IN_NIX_SHELL environment variable is `{}`;".format(in_nix_shell),
-                          "you may need to set `patch-binaries-for-nix=true` in config.toml",
-                          file=sys.stderr)
+                    eprint("The IN_NIX_SHELL environment variable is `{}`;".format(in_nix_shell),
+                          "you may need to set `patch-binaries-for-nix=true` in config.toml")
 
             return is_nixos
 
         answer = self._should_fix_bins_and_dylibs = get_answer()
         if answer:
-            print("info: You seem to be using Nix.", file=sys.stderr)
+            eprint("info: You seem to be using Nix.")
         return answer
 
     def fix_bin_or_dylib(self, fname):
@@ -693,7 +694,7 @@ class RustBuild(object):
         Please see https://nixos.org/patchelf.html for more information
         """
         assert self._should_fix_bins_and_dylibs is True
-        print("attempting to patch", fname, file=sys.stderr)
+        eprint("attempting to patch", fname)
 
         # Only build `.nix-deps` once.
         nix_deps_dir = self.nix_deps_dir
@@ -726,7 +727,7 @@ class RustBuild(object):
                     "nix-build", "-E", nix_expr, "-o", nix_deps_dir,
                 ])
             except subprocess.CalledProcessError as reason:
-                print("warning: failed to call nix-build:", reason, file=sys.stderr)
+                eprint("warning: failed to call nix-build:", reason)
                 return
             self.nix_deps_dir = nix_deps_dir
 
@@ -746,7 +747,7 @@ class RustBuild(object):
         try:
             subprocess.check_output([patchelf] + patchelf_args + [fname])
         except subprocess.CalledProcessError as reason:
-            print("warning: failed to call patchelf:", reason, file=sys.stderr)
+            eprint("warning: failed to call patchelf:", reason)
             return
 
     def rustc_stamp(self):
@@ -888,7 +889,7 @@ class RustBuild(object):
         if "GITHUB_ACTIONS" in env:
             print("::group::Building bootstrap")
         else:
-            print("Building bootstrap", file=sys.stderr)
+            eprint("Building bootstrap")
 
         args = self.build_bootstrap_cmd(env)
         # Run this from the source directory so cargo finds .cargo/config
@@ -997,12 +998,9 @@ class RustBuild(object):
         if 'SUDO_USER' in os.environ and not self.use_vendored_sources:
             if os.getuid() == 0:
                 self.use_vendored_sources = True
-                print('info: looks like you\'re trying to run this command as root',
-                    file=sys.stderr)
-                print('      and so in order to preserve your $HOME this will now',
-                    file=sys.stderr)
-                print('      use vendored sources by default.',
-                    file=sys.stderr)
+                eprint('info: looks like you\'re trying to run this command as root')
+                eprint('      and so in order to preserve your $HOME this will now')
+                eprint('      use vendored sources by default.')
 
         cargo_dir = os.path.join(self.rust_root, '.cargo')
         if self.use_vendored_sources:
@@ -1012,18 +1010,14 @@ class RustBuild(object):
                             "--sync ./src/tools/rust-analyzer/Cargo.toml " \
                             "--sync ./compiler/rustc_codegen_cranelift/Cargo.toml " \
                             "--sync ./src/bootstrap/Cargo.toml "
-                print('error: vendoring required, but vendor directory does not exist.',
-                    file=sys.stderr)
-                print('       Run `cargo vendor {}` to initialize the '
-                      'vendor directory.'.format(sync_dirs),
-                      file=sys.stderr)
-                print('Alternatively, use the pre-vendored `rustc-src` dist component.',
-                    file=sys.stderr)
+                eprint('error: vendoring required, but vendor directory does not exist.')
+                eprint('       Run `cargo vendor {}` to initialize the '
+                      'vendor directory.'.format(sync_dirs))
+                eprint('Alternatively, use the pre-vendored `rustc-src` dist component.')
                 raise Exception("{} not found".format(vendor_dir))
 
             if not os.path.exists(cargo_dir):
-                print('error: vendoring required, but .cargo/config does not exist.',
-                    file=sys.stderr)
+                eprint('error: vendoring required, but .cargo/config does not exist.')
                 raise Exception("{} not found".format(cargo_dir))
         else:
             if os.path.exists(cargo_dir):
@@ -1117,10 +1111,9 @@ def main():
     # If the user is asking for help, let them know that the whole download-and-build
     # process has to happen before anything is printed out.
     if help_triggered:
-        print(
+        eprint(
             "info: Downloading and building bootstrap before processing --help command.\n"
-            "      See src/bootstrap/README.md for help with common commands."
-        , file=sys.stderr)
+            "      See src/bootstrap/README.md for help with common commands.")
 
     exit_code = 0
     success_word = "successfully"
@@ -1131,12 +1124,11 @@ def main():
             exit_code = error.code
         else:
             exit_code = 1
-            print(error, file=sys.stderr)
+            eprint(error)
         success_word = "unsuccessfully"
 
     if not help_triggered:
-        print("Build completed", success_word, "in", format_build_time(time() - start_time),
-            file=sys.stderr)
+        eprint("Build completed", success_word, "in", format_build_time(time() - start_time))
     sys.exit(exit_code)
 
 

src/bootstrap/install.rs

@@ -45,6 +45,23 @@ fn change_drive(s: &str) -> Option<String> {
     }
 }
 
+fn is_dir_writable_for_user(dir: &PathBuf) -> bool {
+    let tmp_file = dir.join(".tmp");
+    match fs::File::create(&tmp_file) {
+        Ok(_) => {
+            fs::remove_file(tmp_file).unwrap();
+            true
+        }
+        Err(e) => {
+            if e.kind() == std::io::ErrorKind::PermissionDenied {
+                false
+            } else {
+                panic!("Failed the write access check for the current user. {}", e);
+            }
+        }
+    }
+}
+
 fn install_sh(
     builder: &Builder<'_>,
     package: &str,
@@ -56,6 +73,17 @@ fn install_sh(
 
     let prefix = default_path(&builder.config.prefix, "/usr/local");
     let sysconfdir = prefix.join(default_path(&builder.config.sysconfdir, "/etc"));
+
+    // Sanity check for the user write access on prefix and sysconfdir
+    assert!(
+        is_dir_writable_for_user(&prefix),
+        "User doesn't have write access on `install.prefix` path in the `config.toml`.",
+    );
+    assert!(
+        is_dir_writable_for_user(&sysconfdir),
+        "User doesn't have write access on `install.sysconfdir` path in `config.toml`."
+    );
+
     let datadir = prefix.join(default_path(&builder.config.datadir, "share"));
     let docdir = prefix.join(default_path(&builder.config.docdir, "share/doc/rust"));
     let mandir = prefix.join(default_path(&builder.config.mandir, "share/man"));
@@ -92,6 +120,9 @@ fn prepare_dir(mut path: PathBuf) -> String {
     // More information on the environment variable is available here:
     // https://www.gnu.org/prep/standards/html_node/DESTDIR.html
     if let Some(destdir) = env::var_os("DESTDIR").map(PathBuf::from) {
+        // Sanity check for the user write access on DESTDIR
+        assert!(is_dir_writable_for_user(&destdir), "User doesn't have write access on DESTDIR.");
+
         let without_destdir = path.clone();
         path = destdir;
         // Custom .join() which ignores disk roots.

src/ci/docker/README.md

@@ -271,7 +271,7 @@ For targets: `loongarch64-unknown-linux-gnu`
 - Operating System > Linux kernel version = 5.19.16
 - Binary utilities > Version of binutils = 2.40
 - C-library > glibc version = 2.36
-- C compiler > gcc version = 13.1.0
+- C compiler > gcc version = 13.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 ### `mips-linux-gnu.defconfig`
@@ -407,7 +407,7 @@ For targets: `riscv64-unknown-linux-gnu`
 - Target options > Bitness = 64-bit
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 4.20.17
-- Binary utilities > Version of binutils = 2.32
+- Binary utilities > Version of binutils = 2.36.1
 - C-library > glibc version = 2.29
 - C compiler > gcc version = 8.5.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM

src/ci/docker/host-x86_64/dist-loongarch64-linux/Dockerfile

@@ -3,9 +3,8 @@ FROM ubuntu:22.04
 COPY scripts/cross-apt-packages.sh /scripts/
 RUN sh /scripts/cross-apt-packages.sh
 
-# The latest released version does not support LoongArch.
-COPY scripts/crosstool-ng-git.sh /scripts/
-RUN sh /scripts/crosstool-ng-git.sh
+COPY scripts/crosstool-ng.sh /scripts/
+RUN sh /scripts/crosstool-ng.sh
 
 COPY scripts/rustbuild-setup.sh /scripts/
 RUN sh /scripts/rustbuild-setup.sh

src/ci/docker/host-x86_64/dist-various-2/Dockerfile

@@ -128,6 +128,8 @@ ENV TARGETS=$TARGETS,armv7-unknown-linux-gnueabi
 ENV TARGETS=$TARGETS,armv7-unknown-linux-musleabi
 ENV TARGETS=$TARGETS,i686-unknown-freebsd
 ENV TARGETS=$TARGETS,x86_64-unknown-none
+ENV TARGETS=$TARGETS,loongarch64-unknown-none
+ENV TARGETS=$TARGETS,loongarch64-unknown-none-softfloat
 ENV TARGETS=$TARGETS,aarch64-unknown-uefi
 ENV TARGETS=$TARGETS,i686-unknown-uefi
 ENV TARGETS=$TARGETS,x86_64-unknown-uefi

src/ci/docker/scripts/crosstool-ng-git.sh

@@ -1,17 +0,0 @@
-#!/bin/sh
-set -ex
-
-URL=https://github.com/crosstool-ng/crosstool-ng
-REV=227d99d7f3115f3a078595a580d2b307dcd23e93
-
-mkdir crosstool-ng
-cd crosstool-ng
-git init
-git fetch --depth=1 ${URL} ${REV}
-git reset --hard FETCH_HEAD
-./bootstrap
-./configure --prefix=/usr/local
-make -j$(nproc)
-make install
-cd ..
-rm -rf crosstool-ng

src/ci/docker/scripts/crosstool-ng.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 set -ex
 
-CT_NG=1.25.0
+CT_NG=1.26.0
 
 url="https://github.com/crosstool-ng/crosstool-ng/archive/crosstool-ng-$CT_NG.tar.gz"
 curl -Lf $url | tar xzf -