Auto merge of #142550 - fmease:rollup-fteyzcv, r=fmease

Rollup of 10 pull requests

Successful merges:

 - rust-lang/rust#133952 (Remove wasm legacy abi)
 - rust-lang/rust#134661 (Reduce precedence of expressions that have an outer attr)
 - rust-lang/rust#141769 (Move metadata object generation for dylibs to the linker code )
 - rust-lang/rust#141937 (Report never type lints in dependencies)
 - rust-lang/rust#142347 (Async drop - fix for StorageLive/StorageDead codegen for pinned future)
 - rust-lang/rust#142389 (Apply ABI attributes on return types in `rustc_codegen_cranelift`)
 - rust-lang/rust#142470 (Add some missing mailmap entries)
 - rust-lang/rust#142481 (Add `f16` inline asm support for LoongArch)
 - rust-lang/rust#142499 (Remove check run bootstrap)
 - rust-lang/rust#142543 (Suggest adding semicolon in user code rather than macro impl details)

r? `@ghost`
`@rustbot` modify labels: rollup

98 files changed, 2791 insertions, 1030 deletions

diff --git a/.mailmap b/.mailmap
index 3b57f88ecab..b9fb7be0403 100644
--- a/.mailmap
+++ b/.mailmap
@@ -34,10 +34,13 @@ Alona Enraght-Moony <code@alona.page> <nixon@caminus.local>
 Alona Enraght-Moony <code@alona.page> <contact@alona.page>
 Amanda Stjerna <mail@amandastjerna.se> <albin.stjerna@gmail.com>
 Amanda Stjerna <mail@amandastjerna.se> <amanda.stjerna@it.uu.se>
+Amanieu d'Antras <amanieu@gmail.com> <amanieu.dantras@huawei.com>
 Amos Onn <amosonn@gmail.com>
 Ana-Maria Mihalache <mihalacheana.maria@yahoo.com>
 Anatoly Ikorsky <aikorsky@gmail.com>
 Andre Bogus <bogusandre@gmail.com>
+Andre Bogus <bogusandre@gmail.com> <andre.bogus@aleph-alpha.de>
+Andre Bogus <bogusandre@gmail.com> <andre.bogus@ankordata.de>
 Andrea Ciliberti <meziu210@icloud.com>
 Andreas Gal <gal@mozilla.com> <andreas.gal@gmail.com>
 Andreas Jonson <andjo403@users.noreply.github.com>
@@ -116,6 +119,7 @@ Carol Willing <carolcode@willingconsulting.com>
 Chandler Deng <chandde@microsoft.com>
 Charles Lew <crlf0710@gmail.com> CrLF0710 <crlf0710@gmail.com>
 Chris C Cerami <chrisccerami@users.noreply.github.com> Chris C Cerami <chrisccerami@gmail.com>
+Chris Denton <chris@chrisdenton.dev> <christophersdenton@gmail.com>
 Chris Denton <chris@chrisdenton.dev> Chris Denton <ChrisDenton@users.noreply.github.com>
 Chris Gregory <czipperz@gmail.com>
 Chris Pardy <chrispardy36@gmail.com>
@@ -403,6 +407,8 @@ Urgau <urgau@numericable.fr> <3616612+Urgau@users.noreply.github.com>
 Lucy <luxx4x@protonmail.com>
 Lukas H. <lukaramu@users.noreply.github.com>
 Lukas Lueg <lukas.lueg@gmail.com>
+Lukas Wirth <lukastw97@gmail.com> <lukas.wirth@ferrous-systems.com>
+Lukas Wirth <lukastw97@gmail.com> <me@lukaswirth.dev>
 Luke Metz <luke.metz@students.olin.edu>
 Luqman Aden <me@luqman.ca> <laden@csclub.uwaterloo.ca>
 Luqman Aden <me@luqman.ca> <laden@mozilla.com>
@@ -493,6 +499,7 @@ Nicolas Abram <abramlujan@gmail.com>
 Nicole Mazzuca <npmazzuca@gmail.com>
 Niko Matsakis <rust@nikomatsakis.com>
 Niko Matsakis <rust@nikomatsakis.com> <niko@alum.mit.edu>
+Niko Matsakis <rust@nikomatsakis.com> <nikomat@amazon.com>
 Noratrieb <48135649+Noratrieb@users.noreply.github.com>
 Noratrieb <48135649+Noratrieb@users.noreply.github.com> <48135649+Nilstrieb@users.noreply.github.com>
 Noratrieb <48135649+Noratrieb@users.noreply.github.com> <nilstrieb@gmail.com>
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 6b51cbd7fbe..4489a424c0d 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1450,11 +1450,20 @@ impl Expr {
     }
 
     pub fn precedence(&self) -> ExprPrecedence {
+        fn prefix_attrs_precedence(attrs: &AttrVec) -> ExprPrecedence {
+            for attr in attrs {
+                if let AttrStyle::Outer = attr.style {
+                    return ExprPrecedence::Prefix;
+                }
+            }
+            ExprPrecedence::Unambiguous
+        }
+
         match &self.kind {
             ExprKind::Closure(closure) => {
                 match closure.fn_decl.output {
                     FnRetTy::Default(_) => ExprPrecedence::Jump,
-                    FnRetTy::Ty(_) => ExprPrecedence::Unambiguous,
+                    FnRetTy::Ty(_) => prefix_attrs_precedence(&self.attrs),
                 }
             }
 
@@ -1463,7 +1472,7 @@ impl Expr {
             | ExprKind::Yield(YieldKind::Prefix(value))
             | ExprKind::Yeet(value) => match value {
                 Some(_) => ExprPrecedence::Jump,
-                None => ExprPrecedence::Unambiguous,
+                None => prefix_attrs_precedence(&self.attrs),
             },
 
             ExprKind::Become(_) => ExprPrecedence::Jump,
@@ -1490,7 +1499,7 @@ impl Expr {
             | ExprKind::Let(..)
             | ExprKind::Unary(..) => ExprPrecedence::Prefix,
 
-            // Never need parens
+            // Need parens if and only if there are prefix attributes.
             ExprKind::Array(_)
             | ExprKind::Await(..)
             | ExprKind::Use(..)
@@ -1525,7 +1534,7 @@ impl Expr {
             | ExprKind::While(..)
             | ExprKind::Yield(YieldKind::Postfix(..))
             | ExprKind::Err(_)
-            | ExprKind::Dummy => ExprPrecedence::Unambiguous,
+            | ExprKind::Dummy => prefix_attrs_precedence(&self.attrs),
         }
     }
 
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index a845431faca..c4b0f503664 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -342,6 +342,10 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                 }
                             }
                         } else if let LocalInfo::BlockTailTemp(info) = local_decl.local_info() {
+                            let sp = info
+                                .span
+                                .find_ancestor_in_same_ctxt(local_decl.source_info.span)
+                                .unwrap_or(info.span);
                             if info.tail_result_is_ignored {
                                 // #85581: If the first mutable borrow's scope contains
                                 // the second borrow, this suggestion isn't helpful.
@@ -349,7 +353,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                     old.to(info.span.shrink_to_hi()).contains(new)
                                 }) {
                                     err.span_suggestion_verbose(
-                                        info.span.shrink_to_hi(),
+                                        sp.shrink_to_hi(),
                                         "consider adding semicolon after the expression so its \
                                         temporaries are dropped sooner, before the local variables \
                                         declared by the block are dropped",
@@ -368,8 +372,8 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                      local variable `x` and then make `x` be the expression at the \
                                      end of the block",
                                     vec![
-                                        (info.span.shrink_to_lo(), "let x = ".to_string()),
-                                        (info.span.shrink_to_hi(), "; x".to_string()),
+                                        (sp.shrink_to_lo(), "let x = ".to_string()),
+                                        (sp.shrink_to_hi(), "; x".to_string()),
                                     ],
                                     Applicability::MaybeIncorrect,
                                 );
diff --git a/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs b/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
index 6d8614aca69..9a0a5b51039 100644
--- a/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
+++ b/compiler/rustc_codegen_cranelift/src/abi/pass_mode.rs
@@ -1,6 +1,6 @@
 //! Argument passing
 
-use cranelift_codegen::ir::{ArgumentExtension, ArgumentPurpose};
+use cranelift_codegen::ir::ArgumentPurpose;
 use rustc_abi::{Reg, RegKind};
 use rustc_target::callconv::{
     ArgAbi, ArgAttributes, ArgExtension as RustcArgExtension, CastTarget, PassMode,
@@ -32,13 +32,12 @@ fn reg_to_abi_param(reg: Reg) -> AbiParam {
     AbiParam::new(clif_ty)
 }
 
-fn apply_arg_attrs_to_abi_param(mut param: AbiParam, arg_attrs: ArgAttributes) -> AbiParam {
+fn apply_attrs_to_abi_param(param: AbiParam, arg_attrs: ArgAttributes) -> AbiParam {
     match arg_attrs.arg_ext {
-        RustcArgExtension::None => {}
-        RustcArgExtension::Zext => param.extension = ArgumentExtension::Uext,
-        RustcArgExtension::Sext => param.extension = ArgumentExtension::Sext,
+        RustcArgExtension::None => param,
+        RustcArgExtension::Zext => param.uext(),
+        RustcArgExtension::Sext => param.sext(),
     }
-    param
 }
 
 fn cast_target_to_abi_params(cast: &CastTarget) -> SmallVec<[AbiParam; 2]> {
@@ -82,7 +81,7 @@ impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
         match self.mode {
             PassMode::Ignore => smallvec![],
             PassMode::Direct(attrs) => match self.layout.backend_repr {
-                BackendRepr::Scalar(scalar) => smallvec![apply_arg_attrs_to_abi_param(
+                BackendRepr::Scalar(scalar) => smallvec![apply_attrs_to_abi_param(
                     AbiParam::new(scalar_to_clif_type(tcx, scalar)),
                     attrs
                 )],
@@ -97,8 +96,8 @@ impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
                     let a = scalar_to_clif_type(tcx, a);
                     let b = scalar_to_clif_type(tcx, b);
                     smallvec![
-                        apply_arg_attrs_to_abi_param(AbiParam::new(a), attrs_a),
-                        apply_arg_attrs_to_abi_param(AbiParam::new(b), attrs_b),
+                        apply_attrs_to_abi_param(AbiParam::new(a), attrs_a),
+                        apply_attrs_to_abi_param(AbiParam::new(b), attrs_b),
                     ]
                 }
                 _ => unreachable!("{:?}", self.layout.backend_repr),
@@ -112,19 +111,19 @@ impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
                     // Abi requires aligning struct size to pointer size
                     let size = self.layout.size.align_to(tcx.data_layout.pointer_align.abi);
                     let size = u32::try_from(size.bytes()).unwrap();
-                    smallvec![apply_arg_attrs_to_abi_param(
+                    smallvec![apply_attrs_to_abi_param(
                         AbiParam::special(pointer_ty(tcx), ArgumentPurpose::StructArgument(size),),
                         attrs
                     )]
                 } else {
-                    smallvec![apply_arg_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), attrs)]
+                    smallvec![apply_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), attrs)]
                 }
             }
             PassMode::Indirect { attrs, meta_attrs: Some(meta_attrs), on_stack } => {
                 assert!(!on_stack);
                 smallvec![
-                    apply_arg_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), attrs),
-                    apply_arg_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), meta_attrs),
+                    apply_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), attrs),
+                    apply_attrs_to_abi_param(AbiParam::new(pointer_ty(tcx)), meta_attrs),
                 ]
             }
         }
@@ -133,30 +132,46 @@ impl<'tcx> ArgAbiExt<'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
     fn get_abi_return(&self, tcx: TyCtxt<'tcx>) -> (Option<AbiParam>, Vec<AbiParam>) {
         match self.mode {
             PassMode::Ignore => (None, vec![]),
-            PassMode::Direct(_) => match self.layout.backend_repr {
-                BackendRepr::Scalar(scalar) => {
-                    (None, vec![AbiParam::new(scalar_to_clif_type(tcx, scalar))])
-                }
+            PassMode::Direct(attrs) => match self.layout.backend_repr {
+                BackendRepr::Scalar(scalar) => (
+                    None,
+                    vec![apply_attrs_to_abi_param(
+                        AbiParam::new(scalar_to_clif_type(tcx, scalar)),
+                        attrs,
+                    )],
+                ),
                 BackendRepr::SimdVector { .. } => {
                     let vector_ty = crate::intrinsics::clif_vector_type(tcx, self.layout);
-                    (None, vec![AbiParam::new(vector_ty)])
+                    (None, vec![apply_attrs_to_abi_param(AbiParam::new(vector_ty), attrs)])
                 }
                 _ => unreachable!("{:?}", self.layout.backend_repr),
             },
-            PassMode::Pair(_, _) => match self.layout.backend_repr {
+            PassMode::Pair(attrs_a, attrs_b) => match self.layout.backend_repr {
                 BackendRepr::ScalarPair(a, b) => {
                     let a = scalar_to_clif_type(tcx, a);
                     let b = scalar_to_clif_type(tcx, b);
-                    (None, vec![AbiParam::new(a), AbiParam::new(b)])
+                    (
+                        None,
+                        vec![
+                            apply_attrs_to_abi_param(AbiParam::new(a), attrs_a),
+                            apply_attrs_to_abi_param(AbiParam::new(b), attrs_b),
+                        ],
+                    )
                 }
                 _ => unreachable!("{:?}", self.layout.backend_repr),
             },
             PassMode::Cast { ref cast, .. } => {
                 (None, cast_target_to_abi_params(cast).into_iter().collect())
             }
-            PassMode::Indirect { attrs: _, meta_attrs: None, on_stack } => {
+            PassMode::Indirect { attrs, meta_attrs: None, on_stack } => {
                 assert!(!on_stack);
-                (Some(AbiParam::special(pointer_ty(tcx), ArgumentPurpose::StructReturn)), vec![])
+                (
+                    Some(apply_attrs_to_abi_param(
+                        AbiParam::special(pointer_ty(tcx), ArgumentPurpose::StructReturn),
+                        attrs,
+                    )),
+                    vec![],
+                )
             }
             PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
                 unreachable!("unsized return value")
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index 5d07c94859f..442151fe32d 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -11,7 +11,6 @@ use std::thread::JoinHandle;
 use cranelift_object::{ObjectBuilder, ObjectModule};
 use rustc_codegen_ssa::assert_module_sources::CguReuse;
 use rustc_codegen_ssa::back::link::ensure_removed;
-use rustc_codegen_ssa::back::metadata::create_compressed_metadata_file;
 use rustc_codegen_ssa::base::determine_cgu_reuse;
 use rustc_codegen_ssa::{
     CodegenResults, CompiledModule, CrateInfo, ModuleKind, errors as ssa_errors,
@@ -19,7 +18,6 @@ use rustc_codegen_ssa::{
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::{IntoDynSyncSend, par_map};
-use rustc_metadata::EncodedMetadata;
 use rustc_metadata::fs::copy_to_stdout;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
@@ -61,8 +59,6 @@ impl<HCX> HashStable<HCX> for OngoingModuleCodegen {
 pub(crate) struct OngoingCodegen {
     modules: Vec<OngoingModuleCodegen>,
     allocator_module: Option<CompiledModule>,
-    metadata_module: Option<CompiledModule>,
-    metadata: EncodedMetadata,
     crate_info: CrateInfo,
     concurrency_limiter: ConcurrencyLimiter,
 }
@@ -134,8 +130,6 @@ impl OngoingCodegen {
         let codegen_results = CodegenResults {
             modules,
             allocator_module: self.allocator_module,
-            metadata_module: self.metadata_module,
-            metadata: self.metadata,
             crate_info: self.crate_info,
         };
 
@@ -646,42 +640,6 @@ fn module_codegen(
     }))
 }
 
-fn emit_metadata_module(tcx: TyCtxt<'_>, metadata: &EncodedMetadata) -> CompiledModule {
-    use rustc_middle::mir::mono::CodegenUnitNameBuilder;
-
-    let _timer = tcx.sess.timer("write compressed metadata");
-
-    let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
-    let metadata_cgu_name = cgu_name_builder
-        .build_cgu_name(LOCAL_CRATE, ["crate"], Some("metadata"))
-        .as_str()
-        .to_string();
-
-    let tmp_file = tcx.output_filenames(()).temp_path_for_cgu(
-        OutputType::Metadata,
-        &metadata_cgu_name,
-        tcx.sess.invocation_temp.as_deref(),
-    );
-
-    let symbol_name = rustc_middle::middle::exported_symbols::metadata_symbol_name(tcx);
-    let obj = create_compressed_metadata_file(tcx.sess, metadata, &symbol_name);
-
-    if let Err(err) = std::fs::write(&tmp_file, obj) {
-        tcx.dcx().fatal(format!("error writing metadata object file: {}", err));
-    }
-
-    CompiledModule {
-        name: metadata_cgu_name,
-        kind: ModuleKind::Metadata,
-        object: Some(tmp_file),
-        dwarf_object: None,
-        bytecode: None,
-        assembly: None,
-        llvm_ir: None,
-        links_from_incr_cache: Vec::new(),
-    }
-}
-
 fn emit_allocator_module(tcx: TyCtxt<'_>) -> Option<CompiledModule> {
     let mut allocator_module = make_module(tcx.sess, "allocator_shim".to_string());
     let created_alloc_shim = crate::allocator::codegen(tcx, &mut allocator_module);
@@ -706,11 +664,7 @@ fn emit_allocator_module(tcx: TyCtxt<'_>) -> Option<CompiledModule> {
     }
 }
 
-pub(crate) fn run_aot(
-    tcx: TyCtxt<'_>,
-    metadata: EncodedMetadata,
-    need_metadata_module: bool,
-) -> Box<OngoingCodegen> {
+pub(crate) fn run_aot(tcx: TyCtxt<'_>) -> Box<OngoingCodegen> {
     // FIXME handle `-Ctarget-cpu=native`
     let target_cpu = match tcx.sess.opts.cg.target_cpu {
         Some(ref name) => name,
@@ -726,8 +680,6 @@ pub(crate) fn run_aot(
         return Box::new(OngoingCodegen {
             modules: vec![],
             allocator_module: None,
-            metadata_module: None,
-            metadata,
             crate_info: CrateInfo::new(tcx, target_cpu),
             concurrency_limiter: ConcurrencyLimiter::new(0),
         });
@@ -787,14 +739,9 @@ pub(crate) fn run_aot(
 
     let allocator_module = emit_allocator_module(tcx);
 
-    let metadata_module =
-        if need_metadata_module { Some(emit_metadata_module(tcx, &metadata)) } else { None };
-
     Box::new(OngoingCodegen {
         modules,
         allocator_module,
-        metadata_module,
-        metadata,
         crate_info: CrateInfo::new(tcx, target_cpu),
         concurrency_limiter: concurrency_limiter.0,
     })
diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs
index 8ef623cde00..07ea29f3024 100644
--- a/compiler/rustc_codegen_cranelift/src/lib.rs
+++ b/compiler/rustc_codegen_cranelift/src/lib.rs
@@ -46,7 +46,6 @@ use cranelift_codegen::isa::TargetIsa;
 use cranelift_codegen::settings::{self, Configurable};
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::{CodegenResults, TargetConfig};
-use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_session::Session;
 use rustc_session::config::OutputFilenames;
@@ -238,12 +237,7 @@ impl CodegenBackend for CraneliftCodegenBackend {
         println!("Cranelift version: {}", cranelift_codegen::VERSION);
     }
 
-    fn codegen_crate(
-        &self,
-        tcx: TyCtxt<'_>,
-        metadata: EncodedMetadata,
-        need_metadata_module: bool,
-    ) -> Box<dyn Any> {
+    fn codegen_crate(&self, tcx: TyCtxt<'_>) -> Box<dyn Any> {
         info!("codegen crate {}", tcx.crate_name(LOCAL_CRATE));
         let config = self.config.clone().unwrap_or_else(|| {
             BackendConfig::from_opts(&tcx.sess.opts.cg.llvm_args)
@@ -256,7 +250,7 @@ impl CodegenBackend for CraneliftCodegenBackend {
             #[cfg(not(feature = "jit"))]
             tcx.dcx().fatal("jit support was disabled when compiling rustc_codegen_cranelift");
         } else {
-            driver::aot::run_aot(tcx, metadata, need_metadata_module)
+            driver::aot::run_aot(tcx)
         }
     }
 
diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs
index 1bd89212100..68c6156fa4b 100644
--- a/compiler/rustc_codegen_gcc/src/builder.rs
+++ b/compiler/rustc_codegen_gcc/src/builder.rs
@@ -30,7 +30,7 @@ use rustc_middle::ty::{self, AtomicOrdering, Instance, Ty, TyCtxt};
 use rustc_span::Span;
 use rustc_span::def_id::DefId;
 use rustc_target::callconv::FnAbi;
-use rustc_target::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, Target, WasmCAbi, X86Abi};
+use rustc_target::spec::{HasTargetSpec, HasX86AbiOpt, Target, X86Abi};
 
 use crate::common::{SignType, TypeReflection, type_is_pointer};
 use crate::context::CodegenCx;
@@ -2394,12 +2394,6 @@ impl<'tcx> HasTargetSpec for Builder<'_, '_, 'tcx> {
     }
 }
 
-impl<'tcx> HasWasmCAbiOpt for Builder<'_, '_, 'tcx> {
-    fn wasm_c_abi_opt(&self) -> WasmCAbi {
-        self.cx.wasm_c_abi_opt()
-    }
-}
-
 impl<'tcx> HasX86AbiOpt for Builder<'_, '_, 'tcx> {
     fn x86_abi_opt(&self) -> X86Abi {
         self.cx.x86_abi_opt()
diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs
index c6c43201f21..4955e039e7b 100644
--- a/compiler/rustc_codegen_gcc/src/context.rs
+++ b/compiler/rustc_codegen_gcc/src/context.rs
@@ -19,9 +19,7 @@ use rustc_middle::ty::{self, ExistentialTraitRef, Instance, Ty, TyCtxt};
 use rustc_session::Session;
 use rustc_span::source_map::respan;
 use rustc_span::{DUMMY_SP, Span};
-use rustc_target::spec::{
-    HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, Target, TlsModel, WasmCAbi, X86Abi,
-};
+use rustc_target::spec::{HasTargetSpec, HasX86AbiOpt, Target, TlsModel, X86Abi};
 
 #[cfg(feature = "master")]
 use crate::abi::conv_to_fn_attribute;
@@ -512,12 +510,6 @@ impl<'gcc, 'tcx> HasTargetSpec for CodegenCx<'gcc, 'tcx> {
     }
 }
 
-impl<'gcc, 'tcx> HasWasmCAbiOpt for CodegenCx<'gcc, 'tcx> {
-    fn wasm_c_abi_opt(&self) -> WasmCAbi {
-        self.tcx.sess.opts.unstable_opts.wasm_c_abi
-    }
-}
-
 impl<'gcc, 'tcx> HasX86AbiOpt for CodegenCx<'gcc, 'tcx> {
     fn x86_abi_opt(&self) -> X86Abi {
         X86Abi {
diff --git a/compiler/rustc_codegen_gcc/src/lib.rs b/compiler/rustc_codegen_gcc/src/lib.rs
index 0591ffa42e4..dbecbc42618 100644
--- a/compiler/rustc_codegen_gcc/src/lib.rs
+++ b/compiler/rustc_codegen_gcc/src/lib.rs
@@ -48,7 +48,6 @@ extern crate rustc_index;
 #[cfg(feature = "master")]
 extern crate rustc_interface;
 extern crate rustc_macros;
-extern crate rustc_metadata;
 extern crate rustc_middle;
 extern crate rustc_session;
 extern crate rustc_span;
@@ -106,7 +105,6 @@ use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen, TargetCon
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::IntoDynSyncSend;
 use rustc_errors::DiagCtxtHandle;
-use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
@@ -230,20 +228,9 @@ impl CodegenBackend for GccCodegenBackend {
         providers.global_backend_features = |tcx, ()| gcc_util::global_gcc_features(tcx.sess, true)
     }
 
-    fn codegen_crate(
-        &self,
-        tcx: TyCtxt<'_>,
-        metadata: EncodedMetadata,
-        need_metadata_module: bool,
-    ) -> Box<dyn Any> {
+    fn codegen_crate(&self, tcx: TyCtxt<'_>) -> Box<dyn Any> {
         let target_cpu = target_cpu(tcx.sess);
-        let res = codegen_crate(
-            self.clone(),
-            tcx,
-            target_cpu.to_string(),
-            metadata,
-            need_metadata_module,
-        );
+        let res = codegen_crate(self.clone(), tcx, target_cpu.to_string());
 
         Box::new(res)
     }
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index 4185aef8b31..9ddadcf16aa 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -1021,6 +1021,15 @@ fn llvm_fixup_input<'ll, 'tcx>(
         ) if element.primitive() == Primitive::Float(Float::F16) => {
             bx.bitcast(value, bx.type_vector(bx.type_i16(), count))
         }
+        (LoongArch(LoongArchInlineAsmRegClass::freg), BackendRepr::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16) =>
+        {
+            // Smaller floats are always "NaN-boxed" inside larger floats on LoongArch.
+            let value = bx.bitcast(value, bx.type_i16());
+            let value = bx.zext(value, bx.type_i32());
+            let value = bx.or(value, bx.const_u32(0xFFFF_0000));
+            bx.bitcast(value, bx.type_f32())
+        }
         (Mips(MipsInlineAsmRegClass::reg), BackendRepr::Scalar(s)) => {
             match s.primitive() {
                 // MIPS only supports register-length arithmetics.
@@ -1178,6 +1187,13 @@ fn llvm_fixup_output<'ll, 'tcx>(
         ) if element.primitive() == Primitive::Float(Float::F16) => {
             bx.bitcast(value, bx.type_vector(bx.type_f16(), count))
         }
+        (LoongArch(LoongArchInlineAsmRegClass::freg), BackendRepr::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16) =>
+        {
+            let value = bx.bitcast(value, bx.type_i32());
+            let value = bx.trunc(value, bx.type_i16());
+            bx.bitcast(value, bx.type_f16())
+        }
         (Mips(MipsInlineAsmRegClass::reg), BackendRepr::Scalar(s)) => {
             match s.primitive() {
                 // MIPS only supports register-length arithmetics.
@@ -1318,6 +1334,11 @@ fn llvm_fixup_output_type<'ll, 'tcx>(
         ) if element.primitive() == Primitive::Float(Float::F16) => {
             cx.type_vector(cx.type_i16(), count)
         }
+        (LoongArch(LoongArchInlineAsmRegClass::freg), BackendRepr::Scalar(s))
+            if s.primitive() == Primitive::Float(Float::F16) =>
+        {
+            cx.type_f32()
+        }
         (Mips(MipsInlineAsmRegClass::reg), BackendRepr::Scalar(s)) => {
             match s.primitive() {
                 // MIPS only supports register-length arithmetics.
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index 6890923a594..cdfffbe47bf 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -340,18 +340,11 @@ impl CodegenBackend for LlvmCodegenBackend {
         target_config(sess)
     }
 
-    fn codegen_crate<'tcx>(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        metadata: EncodedMetadata,
-        need_metadata_module: bool,
-    ) -> Box<dyn Any> {
+    fn codegen_crate<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Box<dyn Any> {
         Box::new(rustc_codegen_ssa::base::codegen_crate(
             LlvmCodegenBackend(()),
             tcx,
             crate::llvm_util::target_cpu(tcx.sess).to_string(),
-            metadata,
-            need_metadata_module,
         ))
     }
 
@@ -376,14 +369,20 @@ impl CodegenBackend for LlvmCodegenBackend {
         (codegen_results, work_products)
     }
 
-    fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) {
+    fn link(
+        &self,
+        sess: &Session,
+        codegen_results: CodegenResults,
+        metadata: EncodedMetadata,
+        outputs: &OutputFilenames,
+    ) {
         use rustc_codegen_ssa::back::link::link_binary;
 
         use crate::back::archive::LlvmArchiveBuilderBuilder;
 
         // Run the linker on any artifacts that resulted from the LLVM run.
         // This should produce either a finished executable or library.
-        link_binary(sess, &LlvmArchiveBuilderBuilder, codegen_results, outputs);
+        link_binary(sess, &LlvmArchiveBuilderBuilder, codegen_results, metadata, outputs);
     }
 }
 
diff --git a/compiler/rustc_codegen_ssa/messages.ftl b/compiler/rustc_codegen_ssa/messages.ftl
index 91f6af7fb93..5322fe58cf3 100644
--- a/compiler/rustc_codegen_ssa/messages.ftl
+++ b/compiler/rustc_codegen_ssa/messages.ftl
@@ -198,8 +198,6 @@ codegen_ssa_linking_failed = linking with `{$linker_path}` failed: {$exit_status
 codegen_ssa_malformed_cgu_name =
     found malformed codegen unit name `{$user_path}`. codegen units names must always start with the name of the crate (`{$crate_name}` in this case).
 
-codegen_ssa_metadata_object_file_write = error writing metadata object file: {$error}
-
 codegen_ssa_missing_cpp_build_tool_component = or a necessary component may be missing from the "C++ build tools" workload
 
 codegen_ssa_missing_features = add the missing features in a `target_feature` attribute
diff --git a/compiler/rustc_codegen_ssa/src/back/archive.rs b/compiler/rustc_codegen_ssa/src/back/archive.rs
index 1e1bdfb5977..84a56f6b0b5 100644
--- a/compiler/rustc_codegen_ssa/src/back/archive.rs
+++ b/compiler/rustc_codegen_ssa/src/back/archive.rs
@@ -14,11 +14,12 @@ use object::read::macho::FatArch;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::memmap::Mmap;
 use rustc_fs_util::TempDirBuilder;
+use rustc_metadata::EncodedMetadata;
 use rustc_session::Session;
 use rustc_span::Symbol;
 use tracing::trace;
 
-use super::metadata::search_for_section;
+use super::metadata::{create_compressed_metadata_file, search_for_section};
 use crate::common;
 // Re-exporting for rustc_codegen_llvm::back::archive
 pub use crate::errors::{ArchiveBuildFailure, ExtractBundledLibsError, UnknownArchiveKind};
@@ -58,6 +59,15 @@ impl From<ImportLibraryItem> for COFFShortExport {
 pub trait ArchiveBuilderBuilder {
     fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder + 'a>;
 
+    fn create_dylib_metadata_wrapper(
+        &self,
+        sess: &Session,
+        metadata: &EncodedMetadata,
+        symbol_name: &str,
+    ) -> Vec<u8> {
+        create_compressed_metadata_file(sess, metadata, symbol_name)
+    }
+
     /// Creates a DLL Import Library <https://docs.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-creation#creating-an-import-library>.
     /// and returns the path on disk to that import library.
     /// This functions doesn't take `self` so that it can be called from
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 18b76b33757..8c52ed6ed12 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -23,7 +23,8 @@ use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_macros::LintDiagnostic;
 use rustc_metadata::fs::{METADATA_FILENAME, copy_to_stdout, emit_wrapper_file};
 use rustc_metadata::{
-    NativeLibSearchFallback, find_native_static_library, walk_native_lib_search_dirs,
+    EncodedMetadata, NativeLibSearchFallback, find_native_static_library,
+    walk_native_lib_search_dirs,
 };
 use rustc_middle::bug;
 use rustc_middle::lint::lint_level;
@@ -91,6 +92,7 @@ pub fn link_binary(
     sess: &Session,
     archive_builder_builder: &dyn ArchiveBuilderBuilder,
     codegen_results: CodegenResults,
+    metadata: EncodedMetadata,
     outputs: &OutputFilenames,
 ) {
     let _timer = sess.timer("link_binary");
@@ -142,6 +144,7 @@ pub fn link_binary(
                         sess,
                         archive_builder_builder,
                         &codegen_results,
+                        &metadata,
                         RlibFlavor::Normal,
                         &path,
                     )
@@ -152,6 +155,7 @@ pub fn link_binary(
                         sess,
                         archive_builder_builder,
                         &codegen_results,
+                        &metadata,
                         &out_filename,
                         &path,
                     );
@@ -163,6 +167,7 @@ pub fn link_binary(
                         crate_type,
                         &out_filename,
                         &codegen_results,
+                        &metadata,
                         path.as_ref(),
                     );
                 }
@@ -226,11 +231,7 @@ pub fn link_binary(
         let remove_temps_from_module =
             |module: &CompiledModule| maybe_remove_temps_from_module(false, false, module);
 
-        // Otherwise, always remove the metadata and allocator module temporaries.
-        if let Some(ref metadata_module) = codegen_results.metadata_module {
-            remove_temps_from_module(metadata_module);
-        }
-
+        // Otherwise, always remove the allocator module temporaries.
         if let Some(ref allocator_module) = codegen_results.allocator_module {
             remove_temps_from_module(allocator_module);
         }
@@ -312,6 +313,7 @@ fn link_rlib<'a>(
     sess: &'a Session,
     archive_builder_builder: &dyn ArchiveBuilderBuilder,
     codegen_results: &CodegenResults,
+    metadata: &EncodedMetadata,
     flavor: RlibFlavor,
     tmpdir: &MaybeTempDir,
 ) -> Box<dyn ArchiveBuilder + 'a> {
@@ -319,12 +321,9 @@ fn link_rlib<'a>(
 
     let trailing_metadata = match flavor {
         RlibFlavor::Normal => {
-            let (metadata, metadata_position) = create_wrapper_file(
-                sess,
-                ".rmeta".to_string(),
-                codegen_results.metadata.stub_or_full(),
-            );
-            let metadata = emit_wrapper_file(sess, &metadata, tmpdir, METADATA_FILENAME);
+            let (metadata, metadata_position) =
+                create_wrapper_file(sess, ".rmeta".to_string(), metadata.stub_or_full());
+            let metadata = emit_wrapper_file(sess, &metadata, tmpdir.as_ref(), METADATA_FILENAME);
             match metadata_position {
                 MetadataPosition::First => {
                     // Most of the time metadata in rlib files is wrapped in a "dummy" object
@@ -392,7 +391,7 @@ fn link_rlib<'a>(
             let src = read(path)
                 .unwrap_or_else(|e| sess.dcx().emit_fatal(errors::ReadFileError { message: e }));
             let (data, _) = create_wrapper_file(sess, ".bundled_lib".to_string(), &src);
-            let wrapper_file = emit_wrapper_file(sess, &data, tmpdir, filename.as_str());
+            let wrapper_file = emit_wrapper_file(sess, &data, tmpdir.as_ref(), filename.as_str());
             packed_bundled_libs.push(wrapper_file);
         } else {
             let path = find_native_static_library(lib.name.as_str(), lib.verbatim, sess);
@@ -473,6 +472,7 @@ fn link_staticlib(
     sess: &Session,
     archive_builder_builder: &dyn ArchiveBuilderBuilder,
     codegen_results: &CodegenResults,
+    metadata: &EncodedMetadata,
     out_filename: &Path,
     tempdir: &MaybeTempDir,
 ) {
@@ -481,6 +481,7 @@ fn link_staticlib(
         sess,
         archive_builder_builder,
         codegen_results,
+        metadata,
         RlibFlavor::StaticlibBase,
         tempdir,
     );
@@ -694,6 +695,7 @@ fn link_natively(
     crate_type: CrateType,
     out_filename: &Path,
     codegen_results: &CodegenResults,
+    metadata: &EncodedMetadata,
     tmpdir: &Path,
 ) {
     info!("preparing {:?} to {:?}", crate_type, out_filename);
@@ -718,6 +720,7 @@ fn link_natively(
         tmpdir,
         temp_filename,
         codegen_results,
+        metadata,
         self_contained_components,
     );
 
@@ -2095,17 +2098,25 @@ fn add_local_crate_allocator_objects(cmd: &mut dyn Linker, codegen_results: &Cod
 /// Add object files containing metadata for the current crate.
 fn add_local_crate_metadata_objects(
     cmd: &mut dyn Linker,
+    sess: &Session,
+    archive_builder_builder: &dyn ArchiveBuilderBuilder,
     crate_type: CrateType,
+    tmpdir: &Path,
     codegen_results: &CodegenResults,
+    metadata: &EncodedMetadata,
 ) {
     // When linking a dynamic library, we put the metadata into a section of the
     // executable. This metadata is in a separate object file from the main
-    // object file, so we link that in here.
-    if matches!(crate_type, CrateType::Dylib | CrateType::ProcMacro)
-        && let Some(m) = &codegen_results.metadata_module
-        && let Some(obj) = &m.object
-    {
-        cmd.add_object(obj);
+    // object file, so we create and link it in here.
+    if matches!(crate_type, CrateType::Dylib | CrateType::ProcMacro) {
+        let data = archive_builder_builder.create_dylib_metadata_wrapper(
+            sess,
+            &metadata,
+            &codegen_results.crate_info.metadata_symbol,
+        );
+        let obj = emit_wrapper_file(sess, &data, tmpdir, "rmeta.o");
+
+        cmd.add_object(&obj);
     }
 }
 
@@ -2195,6 +2206,7 @@ fn linker_with_args(
     tmpdir: &Path,
     out_filename: &Path,
     codegen_results: &CodegenResults,
+    metadata: &EncodedMetadata,
     self_contained_components: LinkSelfContainedComponents,
 ) -> Command {
     let self_contained_crt_objects = self_contained_components.is_crt_objects_enabled();
@@ -2269,7 +2281,15 @@ fn linker_with_args(
     // in this DAG so far because they can only depend on other native libraries
     // and such dependencies are also required to be specified.
     add_local_crate_regular_objects(cmd, codegen_results);
-    add_local_crate_metadata_objects(cmd, crate_type, codegen_results);
+    add_local_crate_metadata_objects(
+        cmd,
+        sess,
+        archive_builder_builder,
+        crate_type,
+        tmpdir,
+        codegen_results,
+        metadata,
+    );
     add_local_crate_allocator_objects(cmd, codegen_results);
 
     // Avoid linking to dynamic libraries unless they satisfy some undefined symbols
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index a41ca8ce28b..bbf9cceef2a 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -24,7 +24,6 @@ use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_incremental::{
     copy_cgu_workproduct_to_incr_comp_cache_dir, in_incr_comp_dir, in_incr_comp_dir_sess,
 };
-use rustc_metadata::EncodedMetadata;
 use rustc_metadata::fs::copy_to_stdout;
 use rustc_middle::bug;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
@@ -142,7 +141,6 @@ impl ModuleConfig {
             || match kind {
                 ModuleKind::Regular => sess.opts.output_types.contains_key(&OutputType::Object),
                 ModuleKind::Allocator => false,
-                ModuleKind::Metadata => sess.opts.output_types.contains_key(&OutputType::Metadata),
             };
 
         let emit_obj = if !should_emit_obj {
@@ -350,7 +348,6 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     pub output_filenames: Arc<OutputFilenames>,
     pub invocation_temp: Option<String>,
     pub regular_module_config: Arc<ModuleConfig>,
-    pub metadata_module_config: Arc<ModuleConfig>,
     pub allocator_module_config: Arc<ModuleConfig>,
     pub tm_factory: TargetMachineFactoryFn<B>,
     pub msvc_imps_needed: bool,
@@ -395,7 +392,6 @@ impl<B: WriteBackendMethods> CodegenContext<B> {
     pub fn config(&self, kind: ModuleKind) -> &ModuleConfig {
         match kind {
             ModuleKind::Regular => &self.regular_module_config,
-            ModuleKind::Metadata => &self.metadata_module_config,
             ModuleKind::Allocator => &self.allocator_module_config,
         }
     }
@@ -474,8 +470,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
     backend: B,
     tcx: TyCtxt<'_>,
     target_cpu: String,
-    metadata: EncodedMetadata,
-    metadata_module: Option<CompiledModule>,
 ) -> OngoingCodegen<B> {
     let (coordinator_send, coordinator_receive) = channel();
 
@@ -485,7 +479,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
     let crate_info = CrateInfo::new(tcx, target_cpu);
 
     let regular_config = ModuleConfig::new(ModuleKind::Regular, tcx, no_builtins);
-    let metadata_config = ModuleConfig::new(ModuleKind::Metadata, tcx, no_builtins);
     let allocator_config = ModuleConfig::new(ModuleKind::Allocator, tcx, no_builtins);
 
     let (shared_emitter, shared_emitter_main) = SharedEmitter::new();
@@ -499,15 +492,12 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
         codegen_worker_send,
         coordinator_receive,
         Arc::new(regular_config),
-        Arc::new(metadata_config),
         Arc::new(allocator_config),
         coordinator_send.clone(),
     );
 
     OngoingCodegen {
         backend,
-        metadata,
-        metadata_module,
         crate_info,
 
         codegen_worker_receive,
@@ -843,12 +833,6 @@ pub(crate) fn compute_per_cgu_lto_type(
     sess_crate_types: &[CrateType],
     module_kind: ModuleKind,
 ) -> ComputedLtoType {
-    // Metadata modules never participate in LTO regardless of the lto
-    // settings.
-    if module_kind == ModuleKind::Metadata {
-        return ComputedLtoType::No;
-    }
-
     // If the linker does LTO, we don't have to do it. Note that we
     // keep doing full LTO, if it is requested, as not to break the
     // assumption that the output will be a single module.
@@ -1029,10 +1013,7 @@ fn finish_intra_module_work<B: ExtraBackendMethods>(
     let dcx = cgcx.create_dcx();
     let dcx = dcx.handle();
 
-    if !cgcx.opts.unstable_opts.combine_cgu
-        || module.kind == ModuleKind::Metadata
-        || module.kind == ModuleKind::Allocator
-    {
+    if !cgcx.opts.unstable_opts.combine_cgu || module.kind == ModuleKind::Allocator {
         let module = B::codegen(cgcx, dcx, module, module_config)?;
         Ok(WorkItemResult::Finished(module))
     } else {
@@ -1123,7 +1104,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
     codegen_worker_send: Sender<CguMessage>,
     coordinator_receive: Receiver<Box<dyn Any + Send>>,
     regular_config: Arc<ModuleConfig>,
-    metadata_config: Arc<ModuleConfig>,
     allocator_config: Arc<ModuleConfig>,
     tx_to_llvm_workers: Sender<Box<dyn Any + Send>>,
 ) -> thread::JoinHandle<Result<CompiledModules, ()>> {
@@ -1216,7 +1196,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
         diag_emitter: shared_emitter.clone(),
         output_filenames: Arc::clone(tcx.output_filenames(())),
         regular_module_config: regular_config,
-        metadata_module_config: metadata_config,
         allocator_module_config: allocator_config,
         tm_factory: backend.target_machine_factory(tcx.sess, ol, backend_features),
         msvc_imps_needed: msvc_imps_needed(tcx),
@@ -1673,7 +1652,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
                                     assert!(compiled_allocator_module.is_none());
                                     compiled_allocator_module = Some(compiled_module);
                                 }
-                                ModuleKind::Metadata => bug!("Should be handled separately"),
                             }
                         }
                         Ok(WorkItemResult::NeedsLink(module)) => {
@@ -2055,8 +2033,6 @@ impl<B: ExtraBackendMethods> Drop for Coordinator<B> {
 
 pub struct OngoingCodegen<B: ExtraBackendMethods> {
     pub backend: B,
-    pub metadata: EncodedMetadata,
-    pub metadata_module: Option<CompiledModule>,
     pub crate_info: CrateInfo,
     pub codegen_worker_receive: Receiver<CguMessage>,
     pub shared_emitter_main: SharedEmitterMain,
@@ -2096,12 +2072,10 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
 
         (
             CodegenResults {
-                metadata: self.metadata,
                 crate_info: self.crate_info,
 
                 modules: compiled_modules.modules,
                 allocator_module: compiled_modules.allocator_module,
-                metadata_module: self.metadata_module,
             },
             work_products,
         )
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index c2d6a26de0f..a3d6c73ba85 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -15,11 +15,10 @@ use rustc_data_structures::unord::UnordMap;
 use rustc_hir::ItemId;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
-use rustc_metadata::EncodedMetadata;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::middle::debugger_visualizer::{DebuggerVisualizerFile, DebuggerVisualizerType};
-use rustc_middle::middle::exported_symbols::SymbolExportKind;
-use rustc_middle::middle::{exported_symbols, lang_items};
+use rustc_middle::middle::exported_symbols::{self, SymbolExportKind};
+use rustc_middle::middle::lang_items;
 use rustc_middle::mir::BinOp;
 use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem, MonoItemPartitions};
@@ -28,7 +27,7 @@ use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::Session;
-use rustc_session::config::{self, CrateType, EntryFnType, OutputType};
+use rustc_session::config::{self, CrateType, EntryFnType};
 use rustc_span::{DUMMY_SP, Symbol, sym};
 use rustc_symbol_mangling::mangle_internal_symbol;
 use rustc_trait_selection::infer::{BoundRegionConversionTime, TyCtxtInferExt};
@@ -37,7 +36,6 @@ use tracing::{debug, info};
 
 use crate::assert_module_sources::CguReuse;
 use crate::back::link::are_upstream_rust_objects_already_included;
-use crate::back::metadata::create_compressed_metadata_file;
 use crate::back::write::{
     ComputedLtoType, OngoingCodegen, compute_per_cgu_lto_type, start_async_codegen,
     submit_codegened_module_to_llvm, submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm,
@@ -48,8 +46,7 @@ use crate::mir::operand::OperandValue;
 use crate::mir::place::PlaceRef;
 use crate::traits::*;
 use crate::{
-    CachedModuleCodegen, CodegenLintLevels, CompiledModule, CrateInfo, ModuleCodegen, ModuleKind,
-    errors, meth, mir,
+    CachedModuleCodegen, CodegenLintLevels, CrateInfo, ModuleCodegen, ModuleKind, errors, meth, mir,
 };
 
 pub(crate) fn bin_op_to_icmp_predicate(op: BinOp, signed: bool) -> IntPredicate {
@@ -669,12 +666,10 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
     backend: B,
     tcx: TyCtxt<'_>,
     target_cpu: String,
-    metadata: EncodedMetadata,
-    need_metadata_module: bool,
 ) -> OngoingCodegen<B> {
     // Skip crate items and just output metadata in -Z no-codegen mode.
     if tcx.sess.opts.unstable_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() {
-        let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu, metadata, None);
+        let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu);
 
         ongoing_codegen.codegen_finished(tcx);
 
@@ -707,39 +702,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         }
     }
 
-    let metadata_module = need_metadata_module.then(|| {
-        // Emit compressed metadata object.
-        let metadata_cgu_name =
-            cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).to_string();
-        tcx.sess.time("write_compressed_metadata", || {
-            let file_name = tcx.output_filenames(()).temp_path_for_cgu(
-                OutputType::Metadata,
-                &metadata_cgu_name,
-                tcx.sess.invocation_temp.as_deref(),
-            );
-            let data = create_compressed_metadata_file(
-                tcx.sess,
-                &metadata,
-                &exported_symbols::metadata_symbol_name(tcx),
-            );
-            if let Err(error) = std::fs::write(&file_name, data) {
-                tcx.dcx().emit_fatal(errors::MetadataObjectFileWrite { error });
-            }
-            CompiledModule {
-                name: metadata_cgu_name,
-                kind: ModuleKind::Metadata,
-                object: Some(file_name),
-                dwarf_object: None,
-                bytecode: None,
-                assembly: None,
-                llvm_ir: None,
-                links_from_incr_cache: Vec::new(),
-            }
-        })
-    });
-
-    let ongoing_codegen =
-        start_async_codegen(backend.clone(), tcx, target_cpu, metadata, metadata_module);
+    let ongoing_codegen = start_async_codegen(backend.clone(), tcx, target_cpu);
 
     // Codegen an allocator shim, if necessary.
     if let Some(kind) = allocator_kind_for_codegen(tcx) {
@@ -1010,6 +973,7 @@ impl CrateInfo {
             windows_subsystem,
             natvis_debugger_visualizers: Default::default(),
             lint_levels: CodegenLintLevels::from_tcx(tcx),
+            metadata_symbol: exported_symbols::metadata_symbol_name(tcx),
         };
 
         info.native_libraries.reserve(n_crates);
diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index f843347db92..bac02bdf983 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -778,12 +778,6 @@ pub(crate) struct MultipleMainFunctions {
 }
 
 #[derive(Diagnostic)]
-#[diag(codegen_ssa_metadata_object_file_write)]
-pub(crate) struct MetadataObjectFileWrite {
-    pub error: Error,
-}
-
-#[derive(Diagnostic)]
 #[diag(codegen_ssa_invalid_windows_subsystem)]
 pub(crate) struct InvalidWindowsSubsystem {
     pub subsystem: Symbol,
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 84919645cf0..523c9f2ad1c 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -31,6 +31,7 @@ use rustc_data_structures::unord::UnordMap;
 use rustc_hir::CRATE_HIR_ID;
 use rustc_hir::def_id::CrateNum;
 use rustc_macros::{Decodable, Encodable, HashStable};
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::lint::LevelAndSource;
 use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
@@ -169,7 +170,6 @@ pub(crate) struct CachedModuleCodegen {
 #[derive(Copy, Clone, Debug, PartialEq, Encodable, Decodable)]
 pub enum ModuleKind {
     Regular,
-    Metadata,
     Allocator,
 }
 
@@ -233,6 +233,7 @@ pub struct CrateInfo {
     pub windows_subsystem: Option<String>,
     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
     pub lint_levels: CodegenLintLevels,
+    pub metadata_symbol: String,
 }
 
 /// Target-specific options that get set in `cfg(...)`.
@@ -257,8 +258,6 @@ pub struct TargetConfig {
 pub struct CodegenResults {
     pub modules: Vec<CompiledModule>,
     pub allocator_module: Option<CompiledModule>,
-    pub metadata_module: Option<CompiledModule>,
-    pub metadata: rustc_metadata::EncodedMetadata,
     pub crate_info: CrateInfo,
 }
 
@@ -303,6 +302,7 @@ impl CodegenResults {
         sess: &Session,
         rlink_file: &Path,
         codegen_results: &CodegenResults,
+        metadata: &EncodedMetadata,
         outputs: &OutputFilenames,
     ) -> Result<usize, io::Error> {
         let mut encoder = FileEncoder::new(rlink_file)?;
@@ -312,6 +312,7 @@ impl CodegenResults {
         encoder.emit_raw_bytes(&RLINK_VERSION.to_be_bytes());
         encoder.emit_str(sess.cfg_version);
         Encodable::encode(codegen_results, &mut encoder);
+        Encodable::encode(metadata, &mut encoder);
         Encodable::encode(outputs, &mut encoder);
         encoder.finish().map_err(|(_path, err)| err)
     }
@@ -319,7 +320,7 @@ impl CodegenResults {
     pub fn deserialize_rlink(
         sess: &Session,
         data: Vec<u8>,
-    ) -> Result<(Self, OutputFilenames), CodegenErrors> {
+    ) -> Result<(Self, EncodedMetadata, OutputFilenames), CodegenErrors> {
         // The Decodable machinery is not used here because it panics if the input data is invalid
         // and because its internal representation may change.
         if !data.starts_with(RLINK_MAGIC) {
@@ -350,8 +351,9 @@ impl CodegenResults {
         }
 
         let codegen_results = CodegenResults::decode(&mut decoder);
+        let metadata = EncodedMetadata::decode(&mut decoder);
         let outputs = OutputFilenames::decode(&mut decoder);
-        Ok((codegen_results, outputs))
+        Ok((codegen_results, metadata, outputs))
     }
 }
 
diff --git a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
index 46fb9a89513..b805dc094e9 100644
--- a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs
@@ -1,14 +1,13 @@
 use rustc_abi::{BackendRepr, Float, Integer, Primitive, RegKind};
 use rustc_attr_data_structures::InstructionSetAttr;
-use rustc_hir::def_id::DefId;
 use rustc_middle::mir::mono::{Linkage, MonoItemData, Visibility};
 use rustc_middle::mir::{InlineAsmOperand, START_BLOCK};
 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
 use rustc_middle::ty::{Instance, Ty, TyCtxt, TypeVisitableExt};
-use rustc_middle::{bug, span_bug, ty};
+use rustc_middle::{bug, ty};
 use rustc_span::sym;
 use rustc_target::callconv::{ArgAbi, FnAbi, PassMode};
-use rustc_target::spec::{BinaryFormat, WasmCAbi};
+use rustc_target::spec::BinaryFormat;
 
 use crate::common;
 use crate::mir::AsmCodegenMethods;
@@ -287,12 +286,7 @@ fn prefix_and_suffix<'tcx>(
                 writeln!(begin, "{}", arch_prefix).unwrap();
             }
             writeln!(begin, "{asm_name}:").unwrap();
-            writeln!(
-                begin,
-                ".functype {asm_name} {}",
-                wasm_functype(tcx, fn_abi, instance.def_id())
-            )
-            .unwrap();
+            writeln!(begin, ".functype {asm_name} {}", wasm_functype(tcx, fn_abi)).unwrap();
 
             writeln!(end).unwrap();
             // .size is ignored for function symbols, so we can skip it
@@ -333,7 +327,7 @@ fn prefix_and_suffix<'tcx>(
 /// The webassembly type signature for the given function.
 ///
 /// Used by the `.functype` directive on wasm targets.
-fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, def_id: DefId) -> String {
+fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> String {
     let mut signature = String::with_capacity(64);
 
     let ptr_type = match tcx.data_layout.pointer_size.bits() {
@@ -342,17 +336,6 @@ fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, def_id
         other => bug!("wasm pointer size cannot be {other} bits"),
     };
 
-    // FIXME: remove this once the wasm32-unknown-unknown ABI is fixed
-    // please also add `wasm32-unknown-unknown` back in `tests/assembly/wasm32-naked-fn.rs`
-    // basically the commit introducing this comment should be reverted
-    if let PassMode::Pair { .. } = fn_abi.ret.mode {
-        let _ = WasmCAbi::Legacy { with_lint: true };
-        span_bug!(
-            tcx.def_span(def_id),
-            "cannot return a pair (the wasm32-unknown-unknown ABI is broken, see https://github.com/rust-lang/rust/issues/115666"
-        );
-    }
-
     let hidden_return = matches!(fn_abi.ret.mode, PassMode::Indirect { .. });
 
     signature.push('(');
@@ -366,7 +349,7 @@ fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, def_id
 
     let mut it = fn_abi.args.iter().peekable();
     while let Some(arg_abi) = it.next() {
-        wasm_type(tcx, &mut signature, arg_abi, ptr_type, def_id);
+        wasm_type(&mut signature, arg_abi, ptr_type);
         if it.peek().is_some() {
             signature.push_str(", ");
         }
@@ -375,7 +358,7 @@ fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, def_id
     signature.push_str(") -> (");
 
     if !hidden_return {
-        wasm_type(tcx, &mut signature, &fn_abi.ret, ptr_type, def_id);
+        wasm_type(&mut signature, &fn_abi.ret, ptr_type);
     }
 
     signature.push(')');
@@ -383,27 +366,13 @@ fn wasm_functype<'tcx>(tcx: TyCtxt<'tcx>, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, def_id
     signature
 }
 
-fn wasm_type<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    signature: &mut String,
-    arg_abi: &ArgAbi<'_, Ty<'tcx>>,
-    ptr_type: &'static str,
-    def_id: DefId,
-) {
+fn wasm_type<'tcx>(signature: &mut String, arg_abi: &ArgAbi<'_, Ty<'tcx>>, ptr_type: &'static str) {
     match arg_abi.mode {
         PassMode::Ignore => { /* do nothing */ }
         PassMode::Direct(_) => {
             let direct_type = match arg_abi.layout.backend_repr {
                 BackendRepr::Scalar(scalar) => wasm_primitive(scalar.primitive(), ptr_type),
                 BackendRepr::SimdVector { .. } => "v128",
-                BackendRepr::Memory { .. } => {
-                    // FIXME: remove this branch once the wasm32-unknown-unknown ABI is fixed
-                    let _ = WasmCAbi::Legacy { with_lint: true };
-                    span_bug!(
-                        tcx.def_span(def_id),
-                        "cannot use memory args (the wasm32-unknown-unknown ABI is broken, see https://github.com/rust-lang/rust/issues/115666"
-                    );
-                }
                 other => unreachable!("unexpected BackendRepr: {:?}", other),
             };
 
diff --git a/compiler/rustc_codegen_ssa/src/traits/backend.rs b/compiler/rustc_codegen_ssa/src/traits/backend.rs
index 95bf3b16685..29ec7eb1da3 100644
--- a/compiler/rustc_codegen_ssa/src/traits/backend.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/backend.rs
@@ -74,12 +74,7 @@ pub trait CodegenBackend {
 
     fn provide(&self, _providers: &mut Providers) {}
 
-    fn codegen_crate<'tcx>(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        metadata: EncodedMetadata,
-        need_metadata_module: bool,
-    ) -> Box<dyn Any>;
+    fn codegen_crate<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Box<dyn Any>;
 
     /// This is called on the returned `Box<dyn Any>` from [`codegen_crate`](Self::codegen_crate)
     ///
@@ -94,8 +89,14 @@ pub trait CodegenBackend {
     ) -> (CodegenResults, FxIndexMap<WorkProductId, WorkProduct>);
 
     /// This is called on the returned [`CodegenResults`] from [`join_codegen`](Self::join_codegen).
-    fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) {
-        link_binary(sess, &ArArchiveBuilderBuilder, codegen_results, outputs);
+    fn link(
+        &self,
+        sess: &Session,
+        codegen_results: CodegenResults,
+        metadata: EncodedMetadata,
+        outputs: &OutputFilenames,
+    ) {
+        link_binary(sess, &ArArchiveBuilderBuilder, codegen_results, metadata, outputs);
     }
 }
 
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 0cd9e36a927..d53126d0414 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -557,27 +557,34 @@ fn process_rlink(sess: &Session, compiler: &interface::Compiler) {
         let rlink_data = fs::read(file).unwrap_or_else(|err| {
             dcx.emit_fatal(RlinkUnableToRead { err });
         });
-        let (codegen_results, outputs) = match CodegenResults::deserialize_rlink(sess, rlink_data) {
-            Ok((codegen, outputs)) => (codegen, outputs),
-            Err(err) => {
-                match err {
-                    CodegenErrors::WrongFileType => dcx.emit_fatal(RLinkWrongFileType),
-                    CodegenErrors::EmptyVersionNumber => dcx.emit_fatal(RLinkEmptyVersionNumber),
-                    CodegenErrors::EncodingVersionMismatch { version_array, rlink_version } => dcx
-                        .emit_fatal(RLinkEncodingVersionMismatch { version_array, rlink_version }),
-                    CodegenErrors::RustcVersionMismatch { rustc_version } => {
-                        dcx.emit_fatal(RLinkRustcVersionMismatch {
-                            rustc_version,
-                            current_version: sess.cfg_version,
-                        })
-                    }
-                    CodegenErrors::CorruptFile => {
-                        dcx.emit_fatal(RlinkCorruptFile { file });
-                    }
-                };
-            }
-        };
-        compiler.codegen_backend.link(sess, codegen_results, &outputs);
+        let (codegen_results, metadata, outputs) =
+            match CodegenResults::deserialize_rlink(sess, rlink_data) {
+                Ok((codegen, metadata, outputs)) => (codegen, metadata, outputs),
+                Err(err) => {
+                    match err {
+                        CodegenErrors::WrongFileType => dcx.emit_fatal(RLinkWrongFileType),
+                        CodegenErrors::EmptyVersionNumber => {
+                            dcx.emit_fatal(RLinkEmptyVersionNumber)
+                        }
+                        CodegenErrors::EncodingVersionMismatch { version_array, rlink_version } => {
+                            dcx.emit_fatal(RLinkEncodingVersionMismatch {
+                                version_array,
+                                rlink_version,
+                            })
+                        }
+                        CodegenErrors::RustcVersionMismatch { rustc_version } => {
+                            dcx.emit_fatal(RLinkRustcVersionMismatch {
+                                rustc_version,
+                                current_version: sess.cfg_version,
+                            })
+                        }
+                        CodegenErrors::CorruptFile => {
+                            dcx.emit_fatal(RlinkCorruptFile { file });
+                        }
+                    };
+                }
+            };
+        compiler.codegen_backend.link(sess, codegen_results, metadata, &outputs);
     } else {
         dcx.emit_fatal(RlinkNotAFile {});
     }
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 3cc6bde8c32..556f50a85af 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -2285,12 +2285,23 @@ pub struct Expr<'hir> {
 }
 
 impl Expr<'_> {
-    pub fn precedence(&self) -> ExprPrecedence {
+    pub fn precedence(
+        &self,
+        for_each_attr: &dyn Fn(HirId, &mut dyn FnMut(&Attribute)),
+    ) -> ExprPrecedence {
+        let prefix_attrs_precedence = || -> ExprPrecedence {
+            let mut has_outer_attr = false;
+            for_each_attr(self.hir_id, &mut |attr: &Attribute| {
+                has_outer_attr |= matches!(attr.style(), AttrStyle::Outer)
+            });
+            if has_outer_attr { ExprPrecedence::Prefix } else { ExprPrecedence::Unambiguous }
+        };
+
         match &self.kind {
             ExprKind::Closure(closure) => {
                 match closure.fn_decl.output {
                     FnRetTy::DefaultReturn(_) => ExprPrecedence::Jump,
-                    FnRetTy::Return(_) => ExprPrecedence::Unambiguous,
+                    FnRetTy::Return(_) => prefix_attrs_precedence(),
                 }
             }
 
@@ -2315,7 +2326,7 @@ impl Expr<'_> {
             | ExprKind::Let(..)
             | ExprKind::Unary(..) => ExprPrecedence::Prefix,
 
-            // Never need parens
+            // Need parens if and only if there are prefix attributes.
             ExprKind::Array(_)
             | ExprKind::Block(..)
             | ExprKind::Call(..)
@@ -2337,9 +2348,9 @@ impl Expr<'_> {
             | ExprKind::Type(..)
             | ExprKind::UnsafeBinderCast(..)
             | ExprKind::Use(..)
-            | ExprKind::Err(_) => ExprPrecedence::Unambiguous,
+            | ExprKind::Err(_) => prefix_attrs_precedence(),
 
-            ExprKind::DropTemps(expr, ..) => expr.precedence(),
+            ExprKind::DropTemps(expr, ..) => expr.precedence(for_each_attr),
         }
     }
 
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index b23b3125c59..fc507285860 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -80,6 +80,13 @@ impl<'a> State<'a> {
         (self.attrs)(id)
     }
 
+    fn precedence(&self, expr: &hir::Expr<'_>) -> ExprPrecedence {
+        let for_each_attr = |id: HirId, callback: &mut dyn FnMut(&hir::Attribute)| {
+            self.attrs(id).iter().for_each(callback);
+        };
+        expr.precedence(&for_each_attr)
+    }
+
     fn print_attrs_as_inner(&mut self, attrs: &[hir::Attribute]) {
         self.print_either_attributes(attrs, ast::AttrStyle::Inner)
     }
@@ -1164,7 +1171,7 @@ impl<'a> State<'a> {
         }
         self.space();
         self.word_space("=");
-        let npals = || parser::needs_par_as_let_scrutinee(init.precedence());
+        let npals = || parser::needs_par_as_let_scrutinee(self.precedence(init));
         self.print_expr_cond_paren(init, Self::cond_needs_par(init) || npals())
     }
 
@@ -1265,7 +1272,7 @@ impl<'a> State<'a> {
     fn print_expr_call(&mut self, func: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
         let needs_paren = match func.kind {
             hir::ExprKind::Field(..) => true,
-            _ => func.precedence() < ExprPrecedence::Unambiguous,
+            _ => self.precedence(func) < ExprPrecedence::Unambiguous,
         };
 
         self.print_expr_cond_paren(func, needs_paren);
@@ -1279,7 +1286,10 @@ impl<'a> State<'a> {
         args: &[hir::Expr<'_>],
     ) {
         let base_args = args;
-        self.print_expr_cond_paren(receiver, receiver.precedence() < ExprPrecedence::Unambiguous);
+        self.print_expr_cond_paren(
+            receiver,
+            self.precedence(receiver) < ExprPrecedence::Unambiguous,
+        );
         self.word(".");
         self.print_ident(segment.ident);
 
@@ -1293,8 +1303,8 @@ impl<'a> State<'a> {
 
     fn print_expr_binary(&mut self, op: hir::BinOpKind, lhs: &hir::Expr<'_>, rhs: &hir::Expr<'_>) {
         let binop_prec = op.precedence();
-        let left_prec = lhs.precedence();
-        let right_prec = rhs.precedence();
+        let left_prec = self.precedence(lhs);
+        let right_prec = self.precedence(rhs);
 
         let (mut left_needs_paren, right_needs_paren) = match op.fixity() {
             Fixity::Left => (left_prec < binop_prec, right_prec <= binop_prec),
@@ -1323,7 +1333,7 @@ impl<'a> State<'a> {
 
     fn print_expr_unary(&mut self, op: hir::UnOp, expr: &hir::Expr<'_>) {
         self.word(op.as_str());
-        self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Prefix);
+        self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Prefix);
     }
 
     fn print_expr_addr_of(
@@ -1340,7 +1350,7 @@ impl<'a> State<'a> {
                 self.print_mutability(mutability, true);
             }
         }
-        self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Prefix);
+        self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Prefix);
     }
 
     fn print_literal(&mut self, lit: &hir::Lit) {
@@ -1483,7 +1493,7 @@ impl<'a> State<'a> {
                 self.print_literal(lit);
             }
             hir::ExprKind::Cast(expr, ty) => {
-                self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Cast);
+                self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Cast);
                 self.space();
                 self.word_space("as");
                 self.print_type(ty);
@@ -1580,24 +1590,30 @@ impl<'a> State<'a> {
                 self.print_block(blk, cb, ib);
             }
             hir::ExprKind::Assign(lhs, rhs, _) => {
-                self.print_expr_cond_paren(lhs, lhs.precedence() <= ExprPrecedence::Assign);
+                self.print_expr_cond_paren(lhs, self.precedence(lhs) <= ExprPrecedence::Assign);
                 self.space();
                 self.word_space("=");
-                self.print_expr_cond_paren(rhs, rhs.precedence() < ExprPrecedence::Assign);
+                self.print_expr_cond_paren(rhs, self.precedence(rhs) < ExprPrecedence::Assign);
             }
             hir::ExprKind::AssignOp(op, lhs, rhs) => {
-                self.print_expr_cond_paren(lhs, lhs.precedence() <= ExprPrecedence::Assign);
+                self.print_expr_cond_paren(lhs, self.precedence(lhs) <= ExprPrecedence::Assign);
                 self.space();
                 self.word_space(op.node.as_str());
-                self.print_expr_cond_paren(rhs, rhs.precedence() < ExprPrecedence::Assign);
+                self.print_expr_cond_paren(rhs, self.precedence(rhs) < ExprPrecedence::Assign);
             }
             hir::ExprKind::Field(expr, ident) => {
-                self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Unambiguous);
+                self.print_expr_cond_paren(
+                    expr,
+                    self.precedence(expr) < ExprPrecedence::Unambiguous,
+                );
                 self.word(".");
                 self.print_ident(ident);
             }
             hir::ExprKind::Index(expr, index, _) => {
-                self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Unambiguous);
+                self.print_expr_cond_paren(
+                    expr,
+                    self.precedence(expr) < ExprPrecedence::Unambiguous,
+                );
                 self.word("[");
                 self.print_expr(index);
                 self.word("]");
@@ -1611,7 +1627,7 @@ impl<'a> State<'a> {
                 }
                 if let Some(expr) = opt_expr {
                     self.space();
-                    self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Jump);
+                    self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump);
                 }
             }
             hir::ExprKind::Continue(destination) => {
@@ -1625,13 +1641,13 @@ impl<'a> State<'a> {
                 self.word("return");
                 if let Some(expr) = result {
                     self.word(" ");
-                    self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Jump);
+                    self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump);
                 }
             }
             hir::ExprKind::Become(result) => {
                 self.word("become");
                 self.word(" ");
-                self.print_expr_cond_paren(result, result.precedence() < ExprPrecedence::Jump);
+                self.print_expr_cond_paren(result, self.precedence(result) < ExprPrecedence::Jump);
             }
             hir::ExprKind::InlineAsm(asm) => {
                 self.word("asm!");
@@ -1669,7 +1685,7 @@ impl<'a> State<'a> {
             }
             hir::ExprKind::Yield(expr, _) => {
                 self.word_space("yield");
-                self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Jump);
+                self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump);
             }
             hir::ExprKind::Err(_) => {
                 self.popen();
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index e915b4fc626..80bff09d0a4 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -620,7 +620,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             };
 
             if let Ok(rest_snippet) = rest_snippet {
-                let sugg = if callee_expr.precedence() >= ExprPrecedence::Unambiguous {
+                let sugg = if self.precedence(callee_expr) >= ExprPrecedence::Unambiguous {
                     vec![
                         (up_to_rcvr_span, "".to_string()),
                         (rest_span, format!(".{}({rest_snippet}", segment.ident)),
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs
index e17cfc15a43..6f8abc1e67d 100644
--- a/compiler/rustc_hir_typeck/src/cast.rs
+++ b/compiler/rustc_hir_typeck/src/cast.rs
@@ -1100,7 +1100,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
     }
 
     fn lossy_provenance_ptr2int_lint(&self, fcx: &FnCtxt<'a, 'tcx>, t_c: ty::cast::IntTy) {
-        let expr_prec = self.expr.precedence();
+        let expr_prec = fcx.precedence(self.expr);
         let needs_parens = expr_prec < ExprPrecedence::Unambiguous;
 
         let needs_cast = !matches!(t_c, ty::cast::IntTy::U(ty::UintTy::Usize));
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 30bf557dc93..55c39d960e7 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -6,6 +6,7 @@
 //! See [`rustc_hir_analysis::check`] for more context on type checking in general.
 
 use rustc_abi::{ExternAbi, FIRST_VARIANT, FieldIdx};
+use rustc_ast::util::parser::ExprPrecedence;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::unord::UnordMap;
@@ -17,7 +18,7 @@ use rustc_errors::{
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
-use rustc_hir::{ExprKind, HirId, QPath};
+use rustc_hir::{Attribute, ExprKind, HirId, QPath};
 use rustc_hir_analysis::NoVariantNamed;
 use rustc_hir_analysis::hir_ty_lowering::{FeedConstTy, HirTyLowerer as _};
 use rustc_infer::infer;
@@ -54,6 +55,30 @@ use crate::{
 };
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
+    pub(crate) fn precedence(&self, expr: &hir::Expr<'_>) -> ExprPrecedence {
+        let for_each_attr = |id: HirId, callback: &mut dyn FnMut(&Attribute)| {
+            for attr in self.tcx.hir_attrs(id) {
+                // For the purpose of rendering suggestions, disregard attributes
+                // that originate from desugaring of any kind. For example, `x?`
+                // desugars to `#[allow(unreachable_code)] match ...`. Failing to
+                // ignore the prefix attribute in the desugaring would cause this
+                // suggestion:
+                //
+                //     let y: u32 = x?.try_into().unwrap();
+                //                    ++++++++++++++++++++
+                //
+                // to be rendered as:
+                //
+                //     let y: u32 = (x?).try_into().unwrap();
+                //                  +  +++++++++++++++++++++
+                if attr.span().desugaring_kind().is_none() {
+                    callback(attr);
+                }
+            }
+        };
+        expr.precedence(&for_each_attr)
+    }
+
     /// Check an expr with an expectation type, and also demand that the expr's
     /// evaluated type is a subtype of the expectation at the end. This is a
     /// *hard* requirement.
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 66af085cfd4..7e5f1d97a8b 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -399,7 +399,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // so we remove the user's `clone` call.
                     {
                         vec![(receiver_method.ident.span, conversion_method_name.to_string())]
-                    } else if expr.precedence() < ExprPrecedence::Unambiguous {
+                    } else if self.precedence(expr) < ExprPrecedence::Unambiguous {
                         vec![
                             (expr.span.shrink_to_lo(), "(".to_string()),
                             (expr.span.shrink_to_hi(), format!(").{}()", conversion_method_name)),
@@ -1395,7 +1395,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         {
             let span = expr.span.find_oldest_ancestor_in_same_ctxt();
 
-            let mut sugg = if expr.precedence() >= ExprPrecedence::Unambiguous {
+            let mut sugg = if self.precedence(expr) >= ExprPrecedence::Unambiguous {
                 vec![(span.shrink_to_hi(), ".into()".to_owned())]
             } else {
                 vec![
@@ -3106,7 +3106,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             "change the type of the numeric literal from `{checked_ty}` to `{expected_ty}`",
         );
 
-        let close_paren = if expr.precedence() < ExprPrecedence::Unambiguous {
+        let close_paren = if self.precedence(expr) < ExprPrecedence::Unambiguous {
             sugg.push((expr.span.shrink_to_lo(), "(".to_string()));
             ")"
         } else {
@@ -3131,7 +3131,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let len = src.trim_end_matches(&checked_ty.to_string()).len();
                 span.with_lo(span.lo() + BytePos(len as u32))
             },
-            if expr.precedence() < ExprPrecedence::Unambiguous {
+            if self.precedence(expr) < ExprPrecedence::Unambiguous {
                 // Readd `)`
                 format!("{expected_ty})")
             } else {
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 0238d6a3947..02d1ebdb31a 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -18,6 +18,7 @@ use rustc_hir::def_id::{LOCAL_CRATE, StableCrateId, StableCrateIdMap};
 use rustc_hir::definitions::Definitions;
 use rustc_incremental::setup_dep_graph;
 use rustc_lint::{BufferedEarlyLint, EarlyCheckNode, LintStore, unerased_lint_store};
+use rustc_metadata::EncodedMetadata;
 use rustc_metadata::creader::CStore;
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepsType;
@@ -1174,7 +1175,7 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) {
 pub(crate) fn start_codegen<'tcx>(
     codegen_backend: &dyn CodegenBackend,
     tcx: TyCtxt<'tcx>,
-) -> Box<dyn Any> {
+) -> (Box<dyn Any>, EncodedMetadata) {
     // Hook for tests.
     if let Some((def_id, _)) = tcx.entry_fn(())
         && tcx.has_attr(def_id, sym::rustc_delayed_bug_from_inside_query)
@@ -1197,11 +1198,9 @@ pub(crate) fn start_codegen<'tcx>(
 
     info!("Pre-codegen\n{:?}", tcx.debug_stats());
 
-    let (metadata, need_metadata_module) = rustc_metadata::fs::encode_and_write_metadata(tcx);
+    let metadata = rustc_metadata::fs::encode_and_write_metadata(tcx);
 
-    let codegen = tcx.sess.time("codegen_crate", move || {
-        codegen_backend.codegen_crate(tcx, metadata, need_metadata_module)
-    });
+    let codegen = tcx.sess.time("codegen_crate", move || codegen_backend.codegen_crate(tcx));
 
     info!("Post-codegen\n{:?}", tcx.debug_stats());
 
@@ -1211,7 +1210,7 @@ pub(crate) fn start_codegen<'tcx>(
         tcx.sess.code_stats.print_type_sizes();
     }
 
-    codegen
+    (codegen, metadata)
 }
 
 /// Compute and validate the crate name.
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index c8914c9be9c..9a474b910f6 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -5,6 +5,7 @@ use rustc_codegen_ssa::CodegenResults;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::svh::Svh;
 use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::DepGraph;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
@@ -18,6 +19,7 @@ pub struct Linker {
     output_filenames: Arc<OutputFilenames>,
     // Only present when incr. comp. is enabled.
     crate_hash: Option<Svh>,
+    metadata: EncodedMetadata,
     ongoing_codegen: Box<dyn Any>,
 }
 
@@ -26,7 +28,7 @@ impl Linker {
         tcx: TyCtxt<'_>,
         codegen_backend: &dyn CodegenBackend,
     ) -> Linker {
-        let ongoing_codegen = passes::start_codegen(codegen_backend, tcx);
+        let (ongoing_codegen, metadata) = passes::start_codegen(codegen_backend, tcx);
 
         Linker {
             dep_graph: tcx.dep_graph.clone(),
@@ -36,6 +38,7 @@ impl Linker {
             } else {
                 None
             },
+            metadata,
             ongoing_codegen,
         }
     }
@@ -75,6 +78,7 @@ impl Linker {
                 sess,
                 &rlink_file,
                 &codegen_results,
+                &self.metadata,
                 &*self.output_filenames,
             )
             .unwrap_or_else(|error| {
@@ -84,6 +88,6 @@ impl Linker {
         }
 
         let _timer = sess.prof.verbose_generic_activity("link_crate");
-        codegen_backend.link(sess, codegen_results, &self.output_filenames)
+        codegen_backend.link(sess, codegen_results, self.metadata, &self.output_filenames)
     }
 }
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 5419d688caa..82823581c12 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -27,7 +27,7 @@ use rustc_span::source_map::{RealFileLoader, SourceMapInputs};
 use rustc_span::{FileName, SourceFileHashAlgorithm, sym};
 use rustc_target::spec::{
     CodeModel, FramePointer, LinkerFlavorCli, MergeFunctions, OnBrokenPipe, PanicStrategy,
-    RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel, WasmCAbi,
+    RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel,
 };
 
 use crate::interface::{initialize_checked_jobserver, parse_cfg};
@@ -882,7 +882,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(verify_llvm_ir, true);
     tracked!(virtual_function_elimination, true);
     tracked!(wasi_exec_model, Some(WasiExecModel::Reactor));
-    tracked!(wasm_c_abi, WasmCAbi::Spec);
     // tidy-alphabetical-end
 
     macro_rules! tracked_no_crate_hash {
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index 5679d4566dc..b6bf45dfbcf 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -7,6 +7,7 @@ use std::cell::Cell;
 use std::slice;
 
 use rustc_ast::BindingMode;
+use rustc_ast::util::parser::ExprPrecedence;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync;
 use rustc_data_structures::unord::UnordMap;
@@ -850,6 +851,20 @@ impl<'tcx> LateContext<'tcx> {
             })
     }
 
+    /// Returns the effective precedence of an expression for the purpose of
+    /// rendering diagnostic. This is not the same as the precedence that would
+    /// be used for pretty-printing HIR by rustc_hir_pretty.
+    pub fn precedence(&self, expr: &hir::Expr<'_>) -> ExprPrecedence {
+        let for_each_attr = |id: hir::HirId, callback: &mut dyn FnMut(&hir::Attribute)| {
+            for attr in self.tcx.hir_attrs(id) {
+                if attr.span().desugaring_kind().is_none() {
+                    callback(attr);
+                }
+            }
+        };
+        expr.precedence(&for_each_attr)
+    }
+
     /// If the given expression is a local binding, find the initializer expression.
     /// If that initializer expression is another local binding, find its initializer again.
     ///
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index e84cdb581b5..9a1490d3eea 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -623,6 +623,7 @@ fn register_builtins(store: &mut LintStore) {
         "converted into hard error, \
          see <https://github.com/rust-lang/rust/issues/40107> for more information",
     );
+    store.register_removed("wasm_c_abi", "the wasm C ABI has been fixed");
 }
 
 fn register_internals(store: &mut LintStore) {
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 295dd82fead..b0ea9689e50 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -140,7 +140,6 @@ declare_lint_pass! {
         UNUSED_VARIABLES,
         USELESS_DEPRECATED,
         WARNINGS,
-        WASM_C_ABI,
         // tidy-alphabetical-end
     ]
 }
@@ -4100,6 +4099,7 @@ declare_lint! {
     @future_incompatible = FutureIncompatibleInfo {
         reason: FutureIncompatibilityReason::EditionAndFutureReleaseSemanticsChange(Edition::Edition2024),
         reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>",
+        report_in_deps: true,
     };
     @edition Edition2024 => Deny;
     report_in_external_macro
@@ -4154,6 +4154,7 @@ declare_lint! {
     @future_incompatible = FutureIncompatibleInfo {
         reason: FutureIncompatibilityReason::EditionAndFutureReleaseError(Edition::Edition2024),
         reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>",
+        report_in_deps: true,
     };
     report_in_external_macro
 }
@@ -4981,50 +4982,6 @@ declare_lint! {
 }
 
 declare_lint! {
-    /// The `wasm_c_abi` lint detects usage of the `extern "C"` ABI of wasm that is affected
-    /// by a planned ABI change that has the goal of aligning Rust with the standard C ABI
-    /// of this target.
-    ///
-    /// ### Example
-    ///
-    /// ```rust,ignore (needs wasm32-unknown-unknown)
-    /// #[repr(C)]
-    /// struct MyType(i32, i32);
-    ///
-    /// extern "C" my_fun(x: MyType) {}
-    /// ```
-    ///
-    /// This will produce:
-    ///
-    /// ```text
-    /// error: this function function definition is affected by the wasm ABI transition: it passes an argument of non-scalar type `MyType`
-    ///   --> $DIR/wasm_c_abi_transition.rs:17:1
-    ///    |
-    ///    | pub extern "C" fn my_fun(_x: MyType) {}
-    ///    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-    ///    |
-    ///    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-    ///    = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-    ///    = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-    /// ```
-    ///
-    /// ### Explanation
-    ///
-    /// Rust has historically implemented a non-spec-compliant C ABI on wasm32-unknown-unknown. This
-    /// has caused incompatibilities with other compilers and Wasm targets. In a future version
-    /// of Rust, this will be fixed, and therefore code relying on the non-spec-compliant C ABI will
-    /// stop functioning.
-    pub WASM_C_ABI,
-    Warn,
-    "detects code relying on rustc's non-spec-compliant wasm C ABI",
-    @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseError,
-        reference: "issue #138762 <https://github.com/rust-lang/rust/issues/138762>",
-        report_in_deps: true,
-    };
-}
-
-declare_lint! {
     /// The `aarch64_softfloat_neon` lint detects usage of `#[target_feature(enable = "neon")]` on
     /// softfloat aarch64 targets. Enabling this target feature causes LLVM to alter the ABI of
     /// function calls, making this attribute unsound to use.
diff --git a/compiler/rustc_metadata/src/fs.rs b/compiler/rustc_metadata/src/fs.rs
index e57534b847e..1eaad26ff8e 100644
--- a/compiler/rustc_metadata/src/fs.rs
+++ b/compiler/rustc_metadata/src/fs.rs
@@ -4,9 +4,9 @@ use std::{fs, io};
 use rustc_data_structures::temp_dir::MaybeTempDir;
 use rustc_fs_util::TempDirBuilder;
 use rustc_middle::ty::TyCtxt;
+use rustc_session::Session;
 use rustc_session::config::{CrateType, OutFileName, OutputType};
 use rustc_session::output::filename_for_metadata;
-use rustc_session::{MetadataKind, Session};
 
 use crate::errors::{
     BinaryOutputToTty, FailedCopyToStdout, FailedCreateEncodedMetadata, FailedCreateFile,
@@ -22,13 +22,8 @@ pub const METADATA_FILENAME: &str = "lib.rmeta";
 /// building an `.rlib` (stomping over one another), or writing an `.rmeta` into a
 /// directory being searched for `extern crate` (observing an incomplete file).
 /// The returned path is the temporary file containing the complete metadata.
-pub fn emit_wrapper_file(
-    sess: &Session,
-    data: &[u8],
-    tmpdir: &MaybeTempDir,
-    name: &str,
-) -> PathBuf {
-    let out_filename = tmpdir.as_ref().join(name);
+pub fn emit_wrapper_file(sess: &Session, data: &[u8], tmpdir: &Path, name: &str) -> PathBuf {
+    let out_filename = tmpdir.join(name);
     let result = fs::write(&out_filename, data);
 
     if let Err(err) = result {
@@ -38,7 +33,7 @@ pub fn emit_wrapper_file(
     out_filename
 }
 
-pub fn encode_and_write_metadata(tcx: TyCtxt<'_>) -> (EncodedMetadata, bool) {
+pub fn encode_and_write_metadata(tcx: TyCtxt<'_>) -> EncodedMetadata {
     let out_filename = filename_for_metadata(tcx.sess, tcx.output_filenames(()));
     // To avoid races with another rustc process scanning the output directory,
     // we need to write the file somewhere else and atomically move it to its
@@ -59,25 +54,20 @@ pub fn encode_and_write_metadata(tcx: TyCtxt<'_>) -> (EncodedMetadata, bool) {
         None
     };
 
-    // Always create a file at `metadata_filename`, even if we have nothing to write to it.
-    // This simplifies the creation of the output `out_filename` when requested.
-    let metadata_kind = tcx.metadata_kind();
-    match metadata_kind {
-        MetadataKind::None => {
-            std::fs::File::create(&metadata_filename).unwrap_or_else(|err| {
-                tcx.dcx().emit_fatal(FailedCreateFile { filename: &metadata_filename, err });
+    if tcx.needs_metadata() {
+        encode_metadata(tcx, &metadata_filename, metadata_stub_filename.as_deref());
+    } else {
+        // Always create a file at `metadata_filename`, even if we have nothing to write to it.
+        // This simplifies the creation of the output `out_filename` when requested.
+        std::fs::File::create(&metadata_filename).unwrap_or_else(|err| {
+            tcx.dcx().emit_fatal(FailedCreateFile { filename: &metadata_filename, err });
+        });
+        if let Some(metadata_stub_filename) = &metadata_stub_filename {
+            std::fs::File::create(metadata_stub_filename).unwrap_or_else(|err| {
+                tcx.dcx().emit_fatal(FailedCreateFile { filename: &metadata_stub_filename, err });
             });
-            if let Some(metadata_stub_filename) = &metadata_stub_filename {
-                std::fs::File::create(metadata_stub_filename).unwrap_or_else(|err| {
-                    tcx.dcx()
-                        .emit_fatal(FailedCreateFile { filename: &metadata_stub_filename, err });
-                });
-            }
-        }
-        MetadataKind::Uncompressed | MetadataKind::Compressed => {
-            encode_metadata(tcx, &metadata_filename, metadata_stub_filename.as_deref())
         }
-    };
+    }
 
     let _prof_timer = tcx.sess.prof.generic_activity("write_crate_metadata");
 
@@ -118,9 +108,7 @@ pub fn encode_and_write_metadata(tcx: TyCtxt<'_>) -> (EncodedMetadata, bool) {
                 tcx.dcx().emit_fatal(FailedCreateEncodedMetadata { err });
             });
 
-    let need_metadata_module = metadata_kind == MetadataKind::Compressed;
-
-    (metadata, need_metadata_module)
+    metadata
 }
 
 #[cfg(not(target_os = "linux"))]
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index b4d8b2e7176..fe4dd8d080b 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -47,7 +47,7 @@ use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
 use rustc_session::config::CrateType;
 use rustc_session::cstore::{CrateStoreDyn, Untracked};
 use rustc_session::lint::Lint;
-use rustc_session::{Limit, MetadataKind, Session};
+use rustc_session::{Limit, Session};
 use rustc_span::def_id::{CRATE_DEF_ID, DefPathHash, StableCrateId};
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use rustc_type_ir::TyKind::*;
@@ -1858,23 +1858,14 @@ impl<'tcx> TyCtxt<'tcx> {
         &self.crate_types
     }
 
-    pub fn metadata_kind(self) -> MetadataKind {
-        self.crate_types()
-            .iter()
-            .map(|ty| match *ty {
-                CrateType::Executable
-                | CrateType::Staticlib
-                | CrateType::Cdylib
-                | CrateType::Sdylib => MetadataKind::None,
-                CrateType::Rlib => MetadataKind::Uncompressed,
-                CrateType::Dylib | CrateType::ProcMacro => MetadataKind::Compressed,
-            })
-            .max()
-            .unwrap_or(MetadataKind::None)
-    }
-
     pub fn needs_metadata(self) -> bool {
-        self.metadata_kind() != MetadataKind::None
+        self.crate_types().iter().any(|ty| match *ty {
+            CrateType::Executable
+            | CrateType::Staticlib
+            | CrateType::Cdylib
+            | CrateType::Sdylib => false,
+            CrateType::Rlib | CrateType::Dylib | CrateType::ProcMacro => true,
+        })
     }
 
     pub fn needs_crate_hash(self) -> bool {
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 9bce2845680..13c281a6182 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -16,9 +16,7 @@ use rustc_macros::{HashStable, TyDecodable, TyEncodable, extension};
 use rustc_session::config::OptLevel;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 use rustc_target::callconv::FnAbi;
-use rustc_target::spec::{
-    HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, PanicStrategy, Target, WasmCAbi, X86Abi,
-};
+use rustc_target::spec::{HasTargetSpec, HasX86AbiOpt, PanicStrategy, Target, X86Abi};
 use tracing::debug;
 use {rustc_abi as abi, rustc_hir as hir};
 
@@ -565,12 +563,6 @@ impl<'tcx> HasTargetSpec for TyCtxt<'tcx> {
     }
 }
 
-impl<'tcx> HasWasmCAbiOpt for TyCtxt<'tcx> {
-    fn wasm_c_abi_opt(&self) -> WasmCAbi {
-        self.sess.opts.unstable_opts.wasm_c_abi
-    }
-}
-
 impl<'tcx> HasX86AbiOpt for TyCtxt<'tcx> {
     fn x86_abi_opt(&self) -> X86Abi {
         X86Abi {
@@ -625,12 +617,6 @@ impl<'tcx> HasTargetSpec for LayoutCx<'tcx> {
     }
 }
 
-impl<'tcx> HasWasmCAbiOpt for LayoutCx<'tcx> {
-    fn wasm_c_abi_opt(&self) -> WasmCAbi {
-        self.calc.cx.wasm_c_abi_opt()
-    }
-}
-
 impl<'tcx> HasX86AbiOpt for LayoutCx<'tcx> {
     fn x86_abi_opt(&self) -> X86Abi {
         self.calc.cx.x86_abi_opt()
diff --git a/compiler/rustc_mir_transform/src/coroutine/drop.rs b/compiler/rustc_mir_transform/src/coroutine/drop.rs
index 6021e795d21..dc68629ec0d 100644
--- a/compiler/rustc_mir_transform/src/coroutine/drop.rs
+++ b/compiler/rustc_mir_transform/src/coroutine/drop.rs
@@ -132,6 +132,7 @@ fn build_poll_switch<'tcx>(
     body: &mut Body<'tcx>,
     poll_enum: Ty<'tcx>,
     poll_unit_place: &Place<'tcx>,
+    fut_pin_place: &Place<'tcx>,
     ready_block: BasicBlock,
     yield_block: BasicBlock,
 ) -> BasicBlock {
@@ -162,9 +163,11 @@ fn build_poll_switch<'tcx>(
             Rvalue::Discriminant(*poll_unit_place),
         ))),
     };
+    let storage_dead =
+        Statement { source_info, kind: StatementKind::StorageDead(fut_pin_place.local) };
     let unreachable_block = insert_term_block(body, TerminatorKind::Unreachable);
     body.basic_blocks_mut().push(BasicBlockData {
-        statements: [discr_assign].to_vec(),
+        statements: [storage_dead, discr_assign].to_vec(),
         terminator: Some(Terminator {
             source_info,
             kind: TerminatorKind::SwitchInt {
@@ -332,10 +335,17 @@ pub(super) fn expand_async_drops<'tcx>(
             kind: StatementKind::Assign(Box::new((context_ref_place, arg))),
         });
         let yield_block = insert_term_block(body, TerminatorKind::Unreachable); // `kind` replaced later to yield
-        let switch_block =
-            build_poll_switch(tcx, body, poll_enum, &poll_unit_place, target, yield_block);
         let (pin_bb, fut_pin_place) =
             build_pin_fut(tcx, body, fut_place.clone(), UnwindAction::Continue);
+        let switch_block = build_poll_switch(
+            tcx,
+            body,
+            poll_enum,
+            &poll_unit_place,
+            &fut_pin_place,
+            target,
+            yield_block,
+        );
         let call_bb = build_poll_call(
             tcx,
             body,
@@ -357,16 +367,17 @@ pub(super) fn expand_async_drops<'tcx>(
                 body.local_decls.push(LocalDecl::new(context_mut_ref, source_info.span)),
             );
             let drop_yield_block = insert_term_block(body, TerminatorKind::Unreachable); // `kind` replaced later to yield
+            let (pin_bb2, fut_pin_place2) =
+                build_pin_fut(tcx, body, fut_place, UnwindAction::Continue);
             let drop_switch_block = build_poll_switch(
                 tcx,
                 body,
                 poll_enum,
                 &poll_unit_place,
+                &fut_pin_place2,
                 drop.unwrap(),
                 drop_yield_block,
             );
-            let (pin_bb2, fut_pin_place2) =
-                build_pin_fut(tcx, body, fut_place, UnwindAction::Continue);
             let drop_call_bb = build_poll_call(
                 tcx,
                 body,
diff --git a/compiler/rustc_mir_transform/src/elaborate_drop.rs b/compiler/rustc_mir_transform/src/elaborate_drop.rs
index 3a5e2620b14..c9bc52c6c7e 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drop.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drop.rs
@@ -390,6 +390,20 @@ where
             Location { block: self.succ, statement_index: 0 },
             StatementKind::StorageDead(fut.local),
         );
+        // StorageDead(fut) in unwind block (at the begin)
+        if let Unwind::To(block) = unwind {
+            self.elaborator.patch().add_statement(
+                Location { block, statement_index: 0 },
+                StatementKind::StorageDead(fut.local),
+            );
+        }
+        // StorageDead(fut) in dropline block (at the begin)
+        if let Some(block) = dropline {
+            self.elaborator.patch().add_statement(
+                Location { block, statement_index: 0 },
+                StatementKind::StorageDead(fut.local),
+            );
+        }
 
         // #1:pin_obj_bb >>> call Pin<ObjTy>::new_unchecked(&mut obj)
         self.elaborator.patch().patch_terminator(
diff --git a/compiler/rustc_monomorphize/messages.ftl b/compiler/rustc_monomorphize/messages.ftl
index 35bedf4318f..2bd19e81b01 100644
--- a/compiler/rustc_monomorphize/messages.ftl
+++ b/compiler/rustc_monomorphize/messages.ftl
@@ -60,11 +60,4 @@ monomorphize_start_not_found = using `fn main` requires the standard library
 
 monomorphize_symbol_already_defined = symbol `{$symbol}` is already defined
 
-monomorphize_wasm_c_abi_transition =
-    this function {$is_call ->
-      [true] call
-      *[false] definition
-    } involves an argument of type `{$ty}` which is affected by the wasm ABI transition
-    .help = the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-
 monomorphize_written_to_path = the full type name has been written to '{$path}'
diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index acf77b5916e..938c427b56c 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -100,12 +100,3 @@ pub(crate) struct AbiRequiredTargetFeature<'a> {
     /// Whether this is a problem at a call site or at a declaration.
     pub is_call: bool,
 }
-
-#[derive(LintDiagnostic)]
-#[diag(monomorphize_wasm_c_abi_transition)]
-#[help]
-pub(crate) struct WasmCAbiTransition<'a> {
-    pub ty: Ty<'a>,
-    /// Whether this is a problem at a call site or at a declaration.
-    pub is_call: bool,
-}
diff --git a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs b/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
index 8dbbb4d1713..b8c001d357e 100644
--- a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
+++ b/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
@@ -3,13 +3,10 @@
 use rustc_abi::{BackendRepr, CanonAbi, RegKind, X86Call};
 use rustc_hir::{CRATE_HIR_ID, HirId};
 use rustc_middle::mir::{self, Location, traversal};
-use rustc_middle::ty::layout::LayoutCx;
-use rustc_middle::ty::{self, Instance, InstanceKind, Ty, TyCtxt, TypingEnv};
-use rustc_session::lint::builtin::WASM_C_ABI;
+use rustc_middle::ty::{self, Instance, InstanceKind, Ty, TyCtxt};
 use rustc_span::def_id::DefId;
 use rustc_span::{DUMMY_SP, Span, Symbol, sym};
-use rustc_target::callconv::{ArgAbi, FnAbi, PassMode};
-use rustc_target::spec::{HasWasmCAbiOpt, WasmCAbi};
+use rustc_target::callconv::{FnAbi, PassMode};
 
 use crate::errors;
 
@@ -81,73 +78,6 @@ fn do_check_simd_vector_abi<'tcx>(
     }
 }
 
-/// Determines whether the given argument is passed the same way on the old and new wasm ABIs.
-fn wasm_abi_safe<'tcx>(tcx: TyCtxt<'tcx>, arg: &ArgAbi<'tcx, Ty<'tcx>>) -> bool {
-    if matches!(arg.layout.backend_repr, BackendRepr::Scalar(_)) {
-        return true;
-    }
-
-    // Both the old and the new ABIs treat vector types like `v128` the same
-    // way.
-    if uses_vector_registers(&arg.mode, &arg.layout.backend_repr) {
-        return true;
-    }
-
-    // This matches `unwrap_trivial_aggregate` in the wasm ABI logic.
-    if arg.layout.is_aggregate() {
-        let cx = LayoutCx::new(tcx, TypingEnv::fully_monomorphized());
-        if let Some(unit) = arg.layout.homogeneous_aggregate(&cx).ok().and_then(|ha| ha.unit()) {
-            let size = arg.layout.size;
-            // Ensure there's just a single `unit` element in `arg`.
-            if unit.size == size {
-                return true;
-            }
-        }
-    }
-
-    // Zero-sized types are dropped in both ABIs, so they're safe
-    if arg.layout.is_zst() {
-        return true;
-    }
-
-    false
-}
-
-/// Warns against usage of `extern "C"` on wasm32-unknown-unknown that is affected by the
-/// ABI transition.
-fn do_check_wasm_abi<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    abi: &FnAbi<'tcx, Ty<'tcx>>,
-    is_call: bool,
-    loc: impl Fn() -> (Span, HirId),
-) {
-    // Only proceed for `extern "C" fn` on wasm32-unknown-unknown (same check as what
-    // `adjust_for_foreign_abi` uses to call `compute_wasm_abi_info`), and only proceed if
-    // `wasm_c_abi_opt` indicates we should emit the lint.
-    if !(tcx.sess.target.arch == "wasm32"
-        && tcx.sess.target.os == "unknown"
-        && tcx.wasm_c_abi_opt() == WasmCAbi::Legacy { with_lint: true }
-        && abi.conv == CanonAbi::C)
-    {
-        return;
-    }
-    // Warn against all types whose ABI will change. Return values are not affected by this change.
-    for arg_abi in abi.args.iter() {
-        if wasm_abi_safe(tcx, arg_abi) {
-            continue;
-        }
-        let (span, hir_id) = loc();
-        tcx.emit_node_span_lint(
-            WASM_C_ABI,
-            hir_id,
-            span,
-            errors::WasmCAbiTransition { ty: arg_abi.layout.ty, is_call },
-        );
-        // Let's only warn once per function.
-        break;
-    }
-}
-
 /// Checks that the ABI of a given instance of a function does not contain vector-passed arguments
 /// or return values for which the corresponding target feature is not enabled.
 fn check_instance_abi<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) {
@@ -173,7 +103,6 @@ fn check_instance_abi<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) {
         )
     };
     do_check_simd_vector_abi(tcx, abi, instance.def_id(), /*is_call*/ false, loc);
-    do_check_wasm_abi(tcx, abi, /*is_call*/ false, loc);
 }
 
 /// Checks that a call expression does not try to pass a vector-passed argument which requires a
@@ -212,7 +141,6 @@ fn check_call_site_abi<'tcx>(
         return;
     };
     do_check_simd_vector_abi(tcx, callee_abi, caller.def_id(), /*is_call*/ true, loc);
-    do_check_wasm_abi(tcx, callee_abi, /*is_call*/ true, loc);
 }
 
 fn check_callees_abi<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>, body: &mir::Body<'tcx>) {
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 8984634e5ec..406a6bd335a 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -3066,7 +3066,7 @@ pub(crate) mod dep_tracking {
     use rustc_target::spec::{
         CodeModel, FramePointer, MergeFunctions, OnBrokenPipe, PanicStrategy, RelocModel,
         RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, SymbolVisibility, TargetTuple,
-        TlsModel, WasmCAbi,
+        TlsModel,
     };
 
     use super::{
@@ -3177,7 +3177,6 @@ pub(crate) mod dep_tracking {
         Polonius,
         InliningThreshold,
         FunctionReturn,
-        WasmCAbi,
         Align,
     );
 
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 6218521d4f0..f76f258d00d 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -16,7 +16,7 @@ use rustc_span::{RealFileName, SourceFileHashAlgorithm};
 use rustc_target::spec::{
     CodeModel, FramePointer, LinkerFlavorCli, MergeFunctions, OnBrokenPipe, PanicStrategy,
     RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, SymbolVisibility,
-    TargetTuple, TlsModel, WasmCAbi,
+    TargetTuple, TlsModel,
 };
 
 use crate::config::*;
@@ -802,7 +802,6 @@ mod desc {
         "either a boolean (`yes`, `no`, `on`, `off`, etc), or a non-negative number";
     pub(crate) const parse_llvm_module_flag: &str = "<key>:<type>:<value>:<behavior>. Type must currently be `u32`. Behavior should be one of (`error`, `warning`, `require`, `override`, `append`, `appendunique`, `max`, `min`)";
     pub(crate) const parse_function_return: &str = "`keep` or `thunk-extern`";
-    pub(crate) const parse_wasm_c_abi: &str = "`legacy` or `spec`";
     pub(crate) const parse_mir_include_spans: &str =
         "either a boolean (`yes`, `no`, `on`, `off`, etc), or `nll` (default: `nll`)";
     pub(crate) const parse_align: &str = "a number that is a power of 2 between 1 and 2^29";
@@ -1898,16 +1897,6 @@ pub mod parse {
         true
     }
 
-    pub(crate) fn parse_wasm_c_abi(slot: &mut WasmCAbi, v: Option<&str>) -> bool {
-        match v {
-            Some("spec") => *slot = WasmCAbi::Spec,
-            // Explicitly setting the `-Z` flag suppresses the lint.
-            Some("legacy") => *slot = WasmCAbi::Legacy { with_lint: false },
-            _ => return false,
-        }
-        true
-    }
-
     pub(crate) fn parse_mir_include_spans(slot: &mut MirIncludeSpans, v: Option<&str>) -> bool {
         *slot = match v {
             Some("on" | "yes" | "y" | "true") | None => MirIncludeSpans::On,
@@ -2642,8 +2631,6 @@ written to standard error output)"),
         Requires `-Clto[=[fat,yes]]`"),
     wasi_exec_model: Option<WasiExecModel> = (None, parse_wasi_exec_model, [TRACKED],
         "whether to build a wasi command or reactor"),
-    wasm_c_abi: WasmCAbi = (WasmCAbi::Legacy { with_lint: true }, parse_wasm_c_abi, [TRACKED],
-        "use spec-compliant C ABI for `wasm32-unknown-unknown` (default: legacy)"),
     write_long_types_to_disk: bool = (true, parse_bool, [UNTRACKED],
         "whether long type names should be written to files instead of being printed in errors"),
     // tidy-alphabetical-end
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 6b85e0abc86..b8b4518b14e 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -215,13 +215,6 @@ pub struct Session {
     pub invocation_temp: Option<String>,
 }
 
-#[derive(PartialEq, Eq, PartialOrd, Ord)]
-pub enum MetadataKind {
-    None,
-    Uncompressed,
-    Compressed,
-}
-
 #[derive(Clone, Copy)]
 pub enum CodegenUnits {
     /// Specified by the user. In this case we try fairly hard to produce the
diff --git a/compiler/rustc_target/src/asm/loongarch.rs b/compiler/rustc_target/src/asm/loongarch.rs
index 8783d3953b1..51e7ee8daa4 100644
--- a/compiler/rustc_target/src/asm/loongarch.rs
+++ b/compiler/rustc_target/src/asm/loongarch.rs
@@ -37,9 +37,11 @@ impl LoongArchInlineAsmRegClass {
         arch: InlineAsmArch,
     ) -> &'static [(InlineAsmType, Option<Symbol>)] {
         match (self, arch) {
-            (Self::reg, InlineAsmArch::LoongArch64) => types! { _: I8, I16, I32, I64, F32, F64; },
-            (Self::reg, InlineAsmArch::LoongArch32) => types! { _: I8, I16, I32, F32; },
-            (Self::freg, _) => types! { f: F32; d: F64; },
+            (Self::reg, InlineAsmArch::LoongArch64) => {
+                types! { _: I8, I16, I32, I64, F16, F32, F64; }
+            }
+            (Self::reg, InlineAsmArch::LoongArch32) => types! { _: I8, I16, I32, F16, F32; },
+            (Self::freg, _) => types! { f: F16, F32; d: F64; },
             _ => unreachable!("unsupported register class"),
         }
     }
diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs
index f9ecf02f857..2ff7a71ca82 100644
--- a/compiler/rustc_target/src/callconv/mod.rs
+++ b/compiler/rustc_target/src/callconv/mod.rs
@@ -7,7 +7,7 @@ use rustc_abi::{
 use rustc_macros::HashStable_Generic;
 
 pub use crate::spec::AbiMap;
-use crate::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, WasmCAbi};
+use crate::spec::{HasTargetSpec, HasX86AbiOpt};
 
 mod aarch64;
 mod amdgpu;
@@ -593,7 +593,7 @@ impl<'a, Ty> FnAbi<'a, Ty> {
     pub fn adjust_for_foreign_abi<C>(&mut self, cx: &C, abi: ExternAbi)
     where
         Ty: TyAbiInterface<'a, C> + Copy,
-        C: HasDataLayout + HasTargetSpec + HasWasmCAbiOpt + HasX86AbiOpt,
+        C: HasDataLayout + HasTargetSpec + HasX86AbiOpt,
     {
         if abi == ExternAbi::X86Interrupt {
             if let Some(arg) = self.args.first_mut() {
@@ -669,14 +669,7 @@ impl<'a, Ty> FnAbi<'a, Ty> {
             "hexagon" => hexagon::compute_abi_info(self),
             "xtensa" => xtensa::compute_abi_info(cx, self),
             "riscv32" | "riscv64" => riscv::compute_abi_info(cx, self),
-            "wasm32" => {
-                if spec.os == "unknown" && matches!(cx.wasm_c_abi_opt(), WasmCAbi::Legacy { .. }) {
-                    wasm::compute_wasm_abi_info(self)
-                } else {
-                    wasm::compute_c_abi_info(cx, self)
-                }
-            }
-            "wasm64" => wasm::compute_c_abi_info(cx, self),
+            "wasm32" | "wasm64" => wasm::compute_abi_info(cx, self),
             "bpf" => bpf::compute_abi_info(self),
             arch => panic!("no lowering implemented for {arch}"),
         }
diff --git a/compiler/rustc_target/src/callconv/wasm.rs b/compiler/rustc_target/src/callconv/wasm.rs
index 881168c98c3..a308f378ee8 100644
--- a/compiler/rustc_target/src/callconv/wasm.rs
+++ b/compiler/rustc_target/src/callconv/wasm.rs
@@ -59,7 +59,7 @@ where
 }
 
 /// The purpose of this ABI is to match the C ABI (aka clang) exactly.
-pub(crate) fn compute_c_abi_info<'a, Ty, C>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>)
+pub(crate) fn compute_abi_info<'a, Ty, C>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>)
 where
     Ty: TyAbiInterface<'a, C> + Copy,
     C: HasDataLayout,
@@ -75,43 +75,3 @@ where
         classify_arg(cx, arg);
     }
 }
-
-/// The purpose of this ABI is for matching the WebAssembly standard. This
-/// intentionally diverges from the C ABI and is specifically crafted to take
-/// advantage of LLVM's support of multiple returns in WebAssembly.
-///
-/// This ABI is *bad*! It uses `PassMode::Direct` for `abi::Aggregate` types, which leaks LLVM
-/// implementation details into the ABI. It's just hard to fix because ABIs are hard to change.
-/// Also see <https://github.com/rust-lang/rust/issues/115666>.
-pub(crate) fn compute_wasm_abi_info<Ty>(fn_abi: &mut FnAbi<'_, Ty>) {
-    if !fn_abi.ret.is_ignore() {
-        classify_ret_wasm_abi(&mut fn_abi.ret);
-    }
-
-    for arg in fn_abi.args.iter_mut() {
-        if arg.is_ignore() {
-            continue;
-        }
-        classify_arg_wasm_abi(arg);
-    }
-
-    fn classify_ret_wasm_abi<Ty>(ret: &mut ArgAbi<'_, Ty>) {
-        if !ret.layout.is_sized() {
-            // Not touching this...
-            return;
-        }
-        // FIXME: this is bad! https://github.com/rust-lang/rust/issues/115666
-        ret.make_direct_deprecated();
-        ret.extend_integer_width_to(32);
-    }
-
-    fn classify_arg_wasm_abi<Ty>(arg: &mut ArgAbi<'_, Ty>) {
-        if !arg.layout.is_sized() {
-            // Not touching this...
-            return;
-        }
-        // FIXME: this is bad! https://github.com/rust-lang/rust/issues/115666
-        arg.make_direct_deprecated();
-        arg.extend_integer_width_to(32);
-    }
-}
diff --git a/compiler/rustc_target/src/callconv/x86_64.rs b/compiler/rustc_target/src/callconv/x86_64.rs
index 300b19f62e7..700ee73c8fd 100644
--- a/compiler/rustc_target/src/callconv/x86_64.rs
+++ b/compiler/rustc_target/src/callconv/x86_64.rs
@@ -7,6 +7,7 @@ use rustc_abi::{
 };
 
 use crate::callconv::{ArgAbi, CastTarget, FnAbi};
+use crate::spec::HasTargetSpec;
 
 /// Classification of "eightbyte" components.
 // N.B., the order of the variants is from general to specific,
@@ -175,7 +176,7 @@ const MAX_SSE_REGS: usize = 8; // XMM0-7
 pub(crate) fn compute_abi_info<'a, Ty, C>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>)
 where
     Ty: TyAbiInterface<'a, C> + Copy,
-    C: HasDataLayout,
+    C: HasDataLayout + HasTargetSpec,
 {
     let mut int_regs = MAX_INT_REGS;
     let mut sse_regs = MAX_SSE_REGS;
@@ -236,7 +237,7 @@ where
                 if arg.layout.is_aggregate() {
                     let size = arg.layout.size;
                     arg.cast_to(cast_target(cls, size));
-                } else {
+                } else if is_arg || cx.target_spec().is_like_darwin {
                     arg.extend_integer_width_to(32);
                 }
             }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index c360fe63a00..010355abd78 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -2233,22 +2233,6 @@ impl HasTargetSpec for Target {
     }
 }
 
-/// Which C ABI to use for `wasm32-unknown-unknown`.
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
-pub enum WasmCAbi {
-    /// Spec-compliant C ABI.
-    Spec,
-    /// Legacy ABI. Which is non-spec-compliant.
-    Legacy {
-        /// Indicates whether the `wasm_c_abi` lint should be emitted.
-        with_lint: bool,
-    },
-}
-
-pub trait HasWasmCAbiOpt {
-    fn wasm_c_abi_opt(&self) -> WasmCAbi;
-}
-
 /// x86 (32-bit) abi options.
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct X86Abi {
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index bb5187e4f5c..f0ff50318ab 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -403,28 +403,18 @@ fn fn_abi_sanity_check<'tcx>(
                         // For an unsized type we'd only pass the sized prefix, so there is no universe
                         // in which we ever want to allow this.
                         assert!(sized, "`PassMode::Direct` for unsized type in ABI: {:#?}", fn_abi);
+
                         // This really shouldn't happen even for sized aggregates, since
                         // `immediate_llvm_type` will use `layout.fields` to turn this Rust type into an
                         // LLVM type. This means all sorts of Rust type details leak into the ABI.
-                        // However wasm sadly *does* currently use this mode for it's "C" ABI so we
-                        // have to allow it -- but we absolutely shouldn't let any more targets do
-                        // that. (Also see <https://github.com/rust-lang/rust/issues/115666>.)
-                        //
-                        // The unadjusted ABI also uses Direct for all args and is ill-specified,
+                        // The unadjusted ABI however uses Direct for all args. It is ill-specified,
                         // but unfortunately we need it for calling certain LLVM intrinsics.
-
-                        match spec_abi {
-                            ExternAbi::Unadjusted => {}
-                            ExternAbi::C { unwind: _ }
-                                if matches!(&*tcx.sess.target.arch, "wasm32" | "wasm64") => {}
-                            _ => {
-                                panic!(
-                                    "`PassMode::Direct` for aggregates only allowed for \"unadjusted\" functions and on wasm\n\
-                                      Problematic type: {:#?}",
-                                    arg.layout,
-                                );
-                            }
-                        }
+                        assert!(
+                            matches!(spec_abi, ExternAbi::Unadjusted),
+                            "`PassMode::Direct` for aggregates only allowed for \"unadjusted\"\n\
+                             Problematic type: {:#?}",
+                            arg.layout,
+                        );
                     }
                 }
             }
diff --git a/library/proc_macro/src/bridge/mod.rs b/library/proc_macro/src/bridge/mod.rs
index 75d82d74654..d60a76fff5d 100644
--- a/library/proc_macro/src/bridge/mod.rs
+++ b/library/proc_macro/src/bridge/mod.rs
@@ -7,9 +7,6 @@
 //! Rust ABIs (e.g., stage0/bin/rustc vs stage1/bin/rustc during bootstrap).
 
 #![deny(unsafe_code)]
-// proc_macros anyway don't work on wasm hosts so while both sides of this bridge can
-// be built with different versions of rustc, the wasm ABI changes don't really matter.
-#![allow(wasm_c_abi)]
 
 use std::hash::Hash;
 use std::ops::{Bound, Range};
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 970a982dae4..f9980ac5fe1 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -1373,12 +1373,13 @@ impl Config {
         }
 
         println!("Updating submodule {relative_path}");
-        self.check_run(
-            helpers::git(Some(&self.src))
-                .run_always()
-                .args(["submodule", "-q", "sync"])
-                .arg(relative_path),
-        );
+
+        helpers::git(Some(&self.src))
+            .allow_failure()
+            .run_always()
+            .args(["submodule", "-q", "sync"])
+            .arg(relative_path)
+            .run(self);
 
         // Try passing `--progress` to start, then run git again without if that fails.
         let update = |progress: bool| {
@@ -1407,26 +1408,23 @@ impl Config {
             git.arg(relative_path);
             git
         };
-        if !self.check_run(&mut update(true)) {
-            self.check_run(&mut update(false));
+        if !update(true).allow_failure().run(self) {
+            update(false).allow_failure().run(self);
         }
 
         // Save any local changes, but avoid running `git stash pop` if there are none (since it will exit with an error).
         // diff-index reports the modifications through the exit status
-        let has_local_modifications = !self.check_run(submodule_git().allow_failure().args([
-            "diff-index",
-            "--quiet",
-            "HEAD",
-        ]));
+        let has_local_modifications =
+            !submodule_git().allow_failure().args(["diff-index", "--quiet", "HEAD"]).run(self);
         if has_local_modifications {
-            self.check_run(submodule_git().args(["stash", "push"]));
+            submodule_git().allow_failure().args(["stash", "push"]).run(self);
         }
 
-        self.check_run(submodule_git().args(["reset", "-q", "--hard"]));
-        self.check_run(submodule_git().args(["clean", "-qdfx"]));
+        submodule_git().allow_failure().args(["reset", "-q", "--hard"]).run(self);
+        submodule_git().allow_failure().args(["clean", "-qdfx"]).run(self);
 
         if has_local_modifications {
-            self.check_run(submodule_git().args(["stash", "pop"]));
+            submodule_git().allow_failure().args(["stash", "pop"]).run(self);
         }
     }
 
diff --git a/src/bootstrap/src/core/download.rs b/src/bootstrap/src/core/download.rs
index 88a58e580e6..d7c6d8dbcc3 100644
--- a/src/bootstrap/src/core/download.rs
+++ b/src/bootstrap/src/core/download.rs
@@ -9,8 +9,8 @@ use xz2::bufread::XzDecoder;
 
 use crate::core::config::BUILDER_CONFIG_FILENAME;
 use crate::utils::build_stamp::BuildStamp;
-use crate::utils::exec::{BootstrapCommand, command};
-use crate::utils::helpers::{check_run, exe, hex_encode, move_file};
+use crate::utils::exec::command;
+use crate::utils::helpers::{exe, hex_encode, move_file};
 use crate::{Config, t};
 
 static SHOULD_FIX_BINS_AND_DYLIBS: OnceLock<bool> = OnceLock::new();
@@ -65,17 +65,6 @@ impl Config {
         tmp
     }
 
-    /// Runs a command, printing out nice contextual information if it fails.
-    /// Returns false if do not execute at all, otherwise returns its
-    /// `status.success()`.
-    pub(crate) fn check_run(&self, cmd: &mut BootstrapCommand) -> bool {
-        if self.dry_run() && !cmd.run_always {
-            return true;
-        }
-        self.verbose(|| println!("running: {cmd:?}"));
-        check_run(cmd, self.is_verbose())
-    }
-
     /// Whether or not `fix_bin_or_dylib` needs to be run; can only be true
     /// on NixOS
     fn should_fix_bins_and_dylibs(&self) -> bool {
@@ -214,7 +203,7 @@ impl Config {
         // options should be kept in sync with
         // src/bootstrap/src/core/download.rs
         // for consistency
-        let mut curl = command("curl");
+        let mut curl = command("curl").allow_failure();
         curl.args([
             // follow redirect
             "--location",
@@ -255,7 +244,7 @@ impl Config {
             curl.arg("--retry-all-errors");
         }
         curl.arg(url);
-        if !self.check_run(&mut curl) {
+        if !curl.run(self) {
             if self.host_target.contains("windows-msvc") {
                 eprintln!("Fallback to PowerShell");
                 for _ in 0..3 {
diff --git a/src/bootstrap/src/utils/helpers.rs b/src/bootstrap/src/utils/helpers.rs
index 3e04e046844..8b2f2dd431e 100644
--- a/src/bootstrap/src/utils/helpers.rs
+++ b/src/bootstrap/src/utils/helpers.rs
@@ -270,24 +270,6 @@ pub fn is_valid_test_suite_arg<'a, P: AsRef<Path>>(
     }
 }
 
-// FIXME: get rid of this function
-pub fn check_run(cmd: &mut BootstrapCommand, print_cmd_on_fail: bool) -> bool {
-    let status = match cmd.as_command_mut().status() {
-        Ok(status) => status,
-        Err(e) => {
-            println!("failed to execute command: {cmd:?}\nERROR: {e}");
-            return false;
-        }
-    };
-    if !status.success() && print_cmd_on_fail {
-        println!(
-            "\n\ncommand did not execute successfully: {cmd:?}\n\
-             expected success, got: {status}\n\n"
-        );
-    }
-    status.success()
-}
-
 pub fn make(host: &str) -> PathBuf {
     if host.contains("dragonfly")
         || host.contains("freebsd")
diff --git a/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md b/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
index b67f49c3a38..1e74c47221c 100644
--- a/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
+++ b/src/doc/rustc/src/platform-support/wasm32-unknown-unknown.md
@@ -207,120 +207,3 @@ conditionally compile code instead. This is notably different to the way native
 platforms such as x86\_64 work, and this is due to the fact that WebAssembly
 binaries must only contain code the engine understands. Native binaries work so
 long as the CPU doesn't execute unknown code dynamically at runtime.
-
-## Broken `extern "C"` ABI
-
-This target has what is considered a broken `extern "C"` ABI implementation at
-this time. Notably the same signature in Rust and C will compile to different
-WebAssembly functions and be incompatible. This is considered a bug and it will
-be fixed in a future version of Rust.
-
-For example this Rust code:
-
-```rust,ignore (does-not-link)
-#[repr(C)]
-struct MyPair {
-    a: u32,
-    b: u32,
-}
-
-extern "C" {
-    fn take_my_pair(pair: MyPair) -> u32;
-}
-
-#[no_mangle]
-pub unsafe extern "C" fn call_c() -> u32 {
-    take_my_pair(MyPair { a: 1, b: 2 })
-}
-```
-
-compiles to a WebAssembly module that looks like:
-
-```wasm
-(module
-  (import "env" "take_my_pair" (func $take_my_pair (param i32 i32) (result i32)))
-  (func $call_c
-    i32.const 1
-    i32.const 2
-    call $take_my_pair
-  )
-)
-```
-
-The function when defined in C, however, looks like
-
-```c
-struct my_pair {
-    unsigned a;
-    unsigned b;
-};
-
-unsigned take_my_pair(struct my_pair pair) {
-    return pair.a + pair.b;
-}
-```
-
-```wasm
-(module
-  (import "env" "__linear_memory" (memory 0))
-  (func $take_my_pair (param i32) (result i32)
-    local.get 0
-    i32.load offset=4
-    local.get 0
-    i32.load
-    i32.add
-  )
-)
-```
-
-Notice how Rust thinks `take_my_pair` takes two `i32` parameters but C thinks it
-only takes one.
-
-The correct definition of the `extern "C"` ABI for WebAssembly is located in the
-[WebAssembly/tool-conventions](https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md)
-repository. The `wasm32-unknown-unknown` target (and only this target, not other
-WebAssembly targets Rust support) does not correctly follow this document.
-
-Example issues in the Rust repository about this bug are:
-
-* [#115666](https://github.com/rust-lang/rust/issues/115666)
-* [#129486](https://github.com/rust-lang/rust/issues/129486)
-
-This current state of the `wasm32-unknown-unknown` backend is due to an
-unfortunate accident which got relied on. The `wasm-bindgen` project prior to
-0.2.89 was incompatible with the "correct" definition of `extern "C"` and it was
-seen as not worth the tradeoff of breaking `wasm-bindgen` historically to fix
-this issue in the compiler.
-
-Thanks to the heroic efforts of many involved in this, however, `wasm-bindgen`
-0.2.89 and later are compatible with the correct definition of `extern "C"` and
-the nightly compiler currently supports a `-Zwasm-c-abi` implemented in
-[#117919](https://github.com/rust-lang/rust/pull/117919). This nightly-only flag
-can be used to indicate whether the spec-defined version of `extern "C"` should
-be used instead of the "legacy" version of
-whatever-the-Rust-target-originally-implemented. For example using the above
-code you can see (lightly edited for clarity):
-
-```shell
-$ rustc +nightly -Zwasm-c-abi=spec foo.rs --target wasm32-unknown-unknown --crate-type lib --emit obj -O
-$ wasm-tools print foo.o
-(module
-  (import "env" "take_my_pair" (func $take_my_pair (param i32) (result i32)))
-  (func $call_c (result i32)
-    ;; ...
-  )
-  ;; ...
-)
-```
-
-which shows that the C and Rust definitions of the same function now agree like
-they should.
-
-The `-Zwasm-c-abi` compiler flag is tracked in
-[#122532](https://github.com/rust-lang/rust/issues/122532) and a lint was
-implemented in [#117918](https://github.com/rust-lang/rust/issues/117918) to
-help warn users about the transition if they're using `wasm-bindgen` 0.2.88 or
-prior. The current plan is to, in the future, switch `-Zwasm-c-api=spec` to
-being the default. Some time after that the `-Zwasm-c-abi` flag and the
-"legacy" implementation will all be removed. During this process users on a
-sufficiently updated version of `wasm-bindgen` should not experience breakage.
diff --git a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
index 8e8c55cf383..010f09d4c1d 100644
--- a/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs
@@ -185,7 +185,7 @@ pub(super) fn check<'tcx>(
             Node::Expr(parent) if is_borrow_expr(cx, parent) && !is_in_allowed_macro(cx, parent) => {
                 MaybeParenOrBlock::Block
             },
-            Node::Expr(parent) if cast_expr.precedence() < parent.precedence() => MaybeParenOrBlock::Paren,
+            Node::Expr(parent) if cx.precedence(cast_expr) < cx.precedence(parent) => MaybeParenOrBlock::Paren,
             _ => MaybeParenOrBlock::Nothing,
         };
 
diff --git a/src/tools/clippy/clippy_lints/src/dereference.rs b/src/tools/clippy/clippy_lints/src/dereference.rs
index cde9528cd87..7463d7b5c3b 100644
--- a/src/tools/clippy/clippy_lints/src/dereference.rs
+++ b/src/tools/clippy/clippy_lints/src/dereference.rs
@@ -972,7 +972,7 @@ fn report<'tcx>(
                 "&"
             };
 
-            let expr_str = if !expr_is_macro_call && is_ufcs && expr.precedence() < ExprPrecedence::Prefix {
+            let expr_str = if !expr_is_macro_call && is_ufcs && cx.precedence(expr) < ExprPrecedence::Prefix {
                 Cow::Owned(format!("({expr_str})"))
             } else {
                 expr_str
@@ -1015,10 +1015,10 @@ fn report<'tcx>(
                         Node::Expr(e) => match e.kind {
                             ExprKind::Call(callee, _) if callee.hir_id != data.first_expr.hir_id => false,
                             ExprKind::Call(..) => {
-                                expr.precedence() < ExprPrecedence::Unambiguous
+                                cx.precedence(expr) < ExprPrecedence::Unambiguous
                                     || matches!(expr.kind, ExprKind::Field(..))
                             },
-                            _ => expr.precedence() < e.precedence(),
+                            _ => cx.precedence(expr) < cx.precedence(e),
                         },
                         _ => false,
                     };
@@ -1066,7 +1066,7 @@ fn report<'tcx>(
                         Mutability::Not => "&",
                         Mutability::Mut => "&mut ",
                     };
-                    (prefix, expr.precedence() < ExprPrecedence::Prefix)
+                    (prefix, cx.precedence(expr) < ExprPrecedence::Prefix)
                 },
                 None if !ty.is_ref() && data.adjusted_ty.is_ref() => ("&", false),
                 _ => ("", false),
@@ -1172,7 +1172,7 @@ impl<'tcx> Dereferencing<'tcx> {
                 },
                 Some(parent) if !parent.span.from_expansion() => {
                     // Double reference might be needed at this point.
-                    if parent.precedence() == ExprPrecedence::Unambiguous {
+                    if cx.precedence(parent) == ExprPrecedence::Unambiguous {
                         // Parentheses would be needed here, don't lint.
                         *outer_pat = None;
                     } else {
diff --git a/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs b/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
index 12719c4f94b..d66771a8b5b 100644
--- a/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/single_element_loop.rs
@@ -84,7 +84,7 @@ pub(super) fn check<'tcx>(
         if !prefix.is_empty()
             && (
                 // Precedence of internal expression is less than or equal to precedence of `&expr`.
-                arg_expression.precedence() <= ExprPrecedence::Prefix || is_range_literal(arg_expression)
+                cx.precedence(arg_expression) <= ExprPrecedence::Prefix || is_range_literal(arg_expression)
             )
         {
             arg_snip = format!("({arg_snip})").into();
diff --git a/src/tools/clippy/clippy_lints/src/matches/manual_utils.rs b/src/tools/clippy/clippy_lints/src/matches/manual_utils.rs
index d0905733ab5..dbae71bbb1b 100644
--- a/src/tools/clippy/clippy_lints/src/matches/manual_utils.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/manual_utils.rs
@@ -117,7 +117,7 @@ where
     // it's being passed by value.
     let scrutinee = peel_hir_expr_refs(scrutinee).0;
     let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
-    let scrutinee_str = if scrutinee.span.eq_ctxt(expr.span) && scrutinee.precedence() < ExprPrecedence::Unambiguous {
+    let scrutinee_str = if scrutinee.span.eq_ctxt(expr.span) && cx.precedence(scrutinee) < ExprPrecedence::Unambiguous {
         format!("({scrutinee_str})")
     } else {
         scrutinee_str.into()
diff --git a/src/tools/clippy/clippy_lints/src/neg_multiply.rs b/src/tools/clippy/clippy_lints/src/neg_multiply.rs
index 74c8142787e..442280f9998 100644
--- a/src/tools/clippy/clippy_lints/src/neg_multiply.rs
+++ b/src/tools/clippy/clippy_lints/src/neg_multiply.rs
@@ -64,7 +64,7 @@ fn check_mul(cx: &LateContext<'_>, span: Span, lit: &Expr<'_>, exp: &Expr<'_>) {
     {
         let mut applicability = Applicability::MachineApplicable;
         let (snip, from_macro) = snippet_with_context(cx, exp.span, span.ctxt(), "..", &mut applicability);
-        let suggestion = if !from_macro && exp.precedence() < ExprPrecedence::Prefix && !has_enclosing_paren(&snip) {
+        let suggestion = if !from_macro && cx.precedence(exp) < ExprPrecedence::Prefix && !has_enclosing_paren(&snip) {
             format!("-({snip})")
         } else {
             format!("-{snip}")
diff --git a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
index 1117dea703c..324a05cdcc0 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_slicing.rs
@@ -86,7 +86,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantSlicing {
             let (indexed_ty, indexed_ref_count) = peel_middle_ty_refs(cx.typeck_results().expr_ty(indexed));
             let parent_expr = get_parent_expr(cx, expr);
             let needs_parens_for_prefix =
-                parent_expr.is_some_and(|parent| parent.precedence() > ExprPrecedence::Prefix);
+                parent_expr.is_some_and(|parent| cx.precedence(parent) > ExprPrecedence::Prefix);
 
             if expr_ty == indexed_ty {
                 if expr_ref_count > indexed_ref_count {
diff --git a/src/tools/clippy/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs b/src/tools/clippy/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs
index 0d5cf45a5e6..18897fbb5b8 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs
@@ -44,7 +44,7 @@ pub(super) fn check<'tcx>(
     };
 
     if let Node::Expr(parent) = cx.tcx.parent_hir_node(e.hir_id)
-        && parent.precedence() > ExprPrecedence::Cast
+        && cx.precedence(parent) > ExprPrecedence::Cast
     {
         sugg = format!("({sugg})");
     }
diff --git a/tests/assembly/asm/loongarch-type.rs b/tests/assembly/asm/loongarch-type.rs
index 86d9e03bc93..c782be19f1d 100644
--- a/tests/assembly/asm/loongarch-type.rs
+++ b/tests/assembly/asm/loongarch-type.rs
@@ -4,7 +4,7 @@
 //@ compile-flags: -Zmerge-functions=disabled
 //@ needs-llvm-components: loongarch
 
-#![feature(no_core)]
+#![feature(no_core, f16)]
 #![crate_type = "rlib"]
 #![no_core]
 #![allow(asm_sub_register, non_camel_case_types)]
@@ -69,6 +69,12 @@ check!(reg_i8, i8, reg, "move");
 // CHECK: #NO_APP
 check!(reg_i16, i16, reg, "move");
 
+// CHECK-LABEL: reg_f16:
+// CHECK: #APP
+// CHECK: move ${{[a-z0-9]+}}, ${{[a-z0-9]+}}
+// CHECK: #NO_APP
+check!(reg_f16, f16, reg, "move");
+
 // CHECK-LABEL: reg_i32:
 // CHECK: #APP
 // CHECK: move ${{[a-z0-9]+}}, ${{[a-z0-9]+}}
@@ -99,6 +105,12 @@ check!(reg_f64, f64, reg, "move");
 // CHECK: #NO_APP
 check!(reg_ptr, ptr, reg, "move");
 
+// CHECK-LABEL: freg_f16:
+// CHECK: #APP
+// CHECK: fmov.s $f{{[a-z0-9]+}}, $f{{[a-z0-9]+}}
+// CHECK: #NO_APP
+check!(freg_f16, f16, freg, "fmov.s");
+
 // CHECK-LABEL: freg_f32:
 // CHECK: #APP
 // CHECK: fmov.s $f{{[a-z0-9]+}}, $f{{[a-z0-9]+}}
@@ -123,6 +135,12 @@ check_reg!(r4_i8, i8, "$r4", "move");
 // CHECK: #NO_APP
 check_reg!(r4_i16, i16, "$r4", "move");
 
+// CHECK-LABEL: r4_f16:
+// CHECK: #APP
+// CHECK: move $a0, $a0
+// CHECK: #NO_APP
+check_reg!(r4_f16, f16, "$r4", "move");
+
 // CHECK-LABEL: r4_i32:
 // CHECK: #APP
 // CHECK: move $a0, $a0
@@ -153,6 +171,12 @@ check_reg!(r4_f64, f64, "$r4", "move");
 // CHECK: #NO_APP
 check_reg!(r4_ptr, ptr, "$r4", "move");
 
+// CHECK-LABEL: f0_f16:
+// CHECK: #APP
+// CHECK: fmov.s $f{{[a-z0-9]+}}, $f{{[a-z0-9]+}}
+// CHECK: #NO_APP
+check_reg!(f0_f16, f16, "$f0", "fmov.s");
+
 // CHECK-LABEL: f0_f32:
 // CHECK: #APP
 // CHECK: fmov.s $f{{[a-z0-9]+}}, $f{{[a-z0-9]+}}
diff --git a/tests/assembly/pic-relocation-model.rs b/tests/assembly/pic-relocation-model.rs
index d35cd968389..15a8723f756 100644
--- a/tests/assembly/pic-relocation-model.rs
+++ b/tests/assembly/pic-relocation-model.rs
@@ -19,7 +19,7 @@ pub fn call_other_fn() -> u8 {
 }
 
 // CHECK-LABEL: other_fn:
-// CHECK:       callq *foreign_fn@GOTPCREL(%rip)
+// CHECK:       {{(jmpq|callq)}} *foreign_fn@GOTPCREL(%rip)
 #[no_mangle]
 #[inline(never)]
 pub fn other_fn() -> u8 {
diff --git a/tests/assembly/pie-relocation-model.rs b/tests/assembly/pie-relocation-model.rs
index 5c74b34eb31..cbe0001041e 100644
--- a/tests/assembly/pie-relocation-model.rs
+++ b/tests/assembly/pie-relocation-model.rs
@@ -22,7 +22,7 @@ pub fn call_other_fn() -> u8 {
 // CHECK-LABEL: other_fn:
 // External functions are still called through GOT, since we don't know if the symbol
 // is defined in the binary or in the shared library.
-// CHECK:       callq *foreign_fn@GOTPCREL(%rip)
+// CHECK:       {{(jmpq|callq)}} *foreign_fn@GOTPCREL(%rip)
 #[no_mangle]
 #[inline(never)]
 pub fn other_fn() -> u8 {
diff --git a/tests/codegen/pie-relocation-model.rs b/tests/codegen/pie-relocation-model.rs
index b10af693452..cb8de91ccd7 100644
--- a/tests/codegen/pie-relocation-model.rs
+++ b/tests/codegen/pie-relocation-model.rs
@@ -13,7 +13,7 @@ pub fn call_foreign_fn() -> u8 {
 
 // External functions are still marked as non-dso_local, since we don't know if the symbol
 // is defined in the binary or in the shared library.
-// CHECK: declare zeroext i8 @foreign_fn()
+// CHECK: declare i8 @foreign_fn()
 extern "C" {
     fn foreign_fn() -> u8;
 }
diff --git a/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-abort.mir b/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-abort.mir
new file mode 100644
index 00000000000..347e4119cd0
--- /dev/null
+++ b/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-abort.mir
@@ -0,0 +1,100 @@
+// MIR for `a::{closure#0}` 0 coroutine_drop_async
+
+fn a::{closure#0}(_1: Pin<&mut {async fn body of a<T>()}>, _2: &mut Context<'_>) -> Poll<()> {
+    debug _task_context => _19;
+    debug x => ((*(_1.0: &mut {async fn body of a<T>()})).0: T);
+    let mut _0: std::task::Poll<()>;
+    let _3: T;
+    let mut _4: impl std::future::Future<Output = ()>;
+    let mut _5: &mut T;
+    let mut _6: std::pin::Pin<&mut T>;
+    let mut _7: &mut T;
+    let mut _8: *mut T;
+    let mut _9: ();
+    let mut _10: std::task::Poll<()>;
+    let mut _11: &mut std::task::Context<'_>;
+    let mut _12: &mut impl std::future::Future<Output = ()>;
+    let mut _13: std::pin::Pin<&mut impl std::future::Future<Output = ()>>;
+    let mut _14: isize;
+    let mut _15: &mut std::task::Context<'_>;
+    let mut _16: &mut impl std::future::Future<Output = ()>;
+    let mut _17: std::pin::Pin<&mut impl std::future::Future<Output = ()>>;
+    let mut _18: isize;
+    let mut _19: &mut std::task::Context<'_>;
+    let mut _20: u32;
+    scope 1 {
+        debug x => (((*(_1.0: &mut {async fn body of a<T>()})) as variant#4).0: T);
+    }
+
+    bb0: {
+        _20 = discriminant((*(_1.0: &mut {async fn body of a<T>()})));
+        switchInt(move _20) -> [0: bb9, 3: bb12, 4: bb13, otherwise: bb14];
+    }
+
+    bb1: {
+        nop;
+        nop;
+        goto -> bb2;
+    }
+
+    bb2: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+
+    bb3: {
+        _0 = Poll::<()>::Pending;
+        discriminant((*(_1.0: &mut {async fn body of a<T>()}))) = 4;
+        return;
+    }
+
+    bb4: {
+        StorageLive(_17);
+        _16 = &mut (((*(_1.0: &mut {async fn body of a<T>()})) as variant#4).1: impl std::future::Future<Output = ()>);
+        _17 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _16) -> [return: bb7, unwind unreachable];
+    }
+
+    bb5: {
+        unreachable;
+    }
+
+    bb6: {
+        StorageDead(_17);
+        _18 = discriminant(_10);
+        switchInt(move _18) -> [0: bb1, 1: bb3, otherwise: bb5];
+    }
+
+    bb7: {
+        _10 = <impl Future<Output = ()> as Future>::poll(move _17, move _15) -> [return: bb6, unwind unreachable];
+    }
+
+    bb8: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+
+    bb9: {
+        goto -> bb11;
+    }
+
+    bb10: {
+        goto -> bb8;
+    }
+
+    bb11: {
+        drop(((*(_1.0: &mut {async fn body of a<T>()})).0: T)) -> [return: bb10, unwind unreachable];
+    }
+
+    bb12: {
+        goto -> bb4;
+    }
+
+    bb13: {
+        goto -> bb4;
+    }
+
+    bb14: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+}
diff --git a/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-unwind.mir b/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-unwind.mir
new file mode 100644
index 00000000000..b1cf5373f91
--- /dev/null
+++ b/tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-unwind.mir
@@ -0,0 +1,123 @@
+// MIR for `a::{closure#0}` 0 coroutine_drop_async
+
+fn a::{closure#0}(_1: Pin<&mut {async fn body of a<T>()}>, _2: &mut Context<'_>) -> Poll<()> {
+    debug _task_context => _19;
+    debug x => ((*(_1.0: &mut {async fn body of a<T>()})).0: T);
+    let mut _0: std::task::Poll<()>;
+    let _3: T;
+    let mut _4: impl std::future::Future<Output = ()>;
+    let mut _5: &mut T;
+    let mut _6: std::pin::Pin<&mut T>;
+    let mut _7: &mut T;
+    let mut _8: *mut T;
+    let mut _9: ();
+    let mut _10: std::task::Poll<()>;
+    let mut _11: &mut std::task::Context<'_>;
+    let mut _12: &mut impl std::future::Future<Output = ()>;
+    let mut _13: std::pin::Pin<&mut impl std::future::Future<Output = ()>>;
+    let mut _14: isize;
+    let mut _15: &mut std::task::Context<'_>;
+    let mut _16: &mut impl std::future::Future<Output = ()>;
+    let mut _17: std::pin::Pin<&mut impl std::future::Future<Output = ()>>;
+    let mut _18: isize;
+    let mut _19: &mut std::task::Context<'_>;
+    let mut _20: u32;
+    scope 1 {
+        debug x => (((*(_1.0: &mut {async fn body of a<T>()})) as variant#4).0: T);
+    }
+
+    bb0: {
+        _20 = discriminant((*(_1.0: &mut {async fn body of a<T>()})));
+        switchInt(move _20) -> [0: bb12, 2: bb18, 3: bb16, 4: bb17, otherwise: bb19];
+    }
+
+    bb1: {
+        nop;
+        nop;
+        goto -> bb2;
+    }
+
+    bb2: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+
+    bb3 (cleanup): {
+        nop;
+        nop;
+        goto -> bb5;
+    }
+
+    bb4 (cleanup): {
+        goto -> bb15;
+    }
+
+    bb5 (cleanup): {
+        goto -> bb4;
+    }
+
+    bb6: {
+        _0 = Poll::<()>::Pending;
+        discriminant((*(_1.0: &mut {async fn body of a<T>()}))) = 4;
+        return;
+    }
+
+    bb7: {
+        StorageLive(_17);
+        _16 = &mut (((*(_1.0: &mut {async fn body of a<T>()})) as variant#4).1: impl std::future::Future<Output = ()>);
+        _17 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _16) -> [return: bb10, unwind: bb15];
+    }
+
+    bb8: {
+        unreachable;
+    }
+
+    bb9: {
+        StorageDead(_17);
+        _18 = discriminant(_10);
+        switchInt(move _18) -> [0: bb1, 1: bb6, otherwise: bb8];
+    }
+
+    bb10: {
+        _10 = <impl Future<Output = ()> as Future>::poll(move _17, move _15) -> [return: bb9, unwind: bb3];
+    }
+
+    bb11: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+
+    bb12: {
+        goto -> bb14;
+    }
+
+    bb13: {
+        goto -> bb11;
+    }
+
+    bb14: {
+        drop(((*(_1.0: &mut {async fn body of a<T>()})).0: T)) -> [return: bb13, unwind: bb4];
+    }
+
+    bb15 (cleanup): {
+        discriminant((*(_1.0: &mut {async fn body of a<T>()}))) = 2;
+        resume;
+    }
+
+    bb16: {
+        goto -> bb7;
+    }
+
+    bb17: {
+        goto -> bb7;
+    }
+
+    bb18: {
+        assert(const false, "`async fn` resumed after panicking") -> [success: bb18, unwind continue];
+    }
+
+    bb19: {
+        _0 = Poll::<()>::Ready(const ());
+        return;
+    }
+}
diff --git a/tests/mir-opt/async_drop_live_dead.rs b/tests/mir-opt/async_drop_live_dead.rs
new file mode 100644
index 00000000000..348866bbb8c
--- /dev/null
+++ b/tests/mir-opt/async_drop_live_dead.rs
@@ -0,0 +1,11 @@
+//@ edition:2024
+// skip-filecheck
+// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
+
+#![feature(async_drop)]
+#![allow(incomplete_features)]
+
+// EMIT_MIR async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.mir
+async fn a<T>(x: T) {}
+
+fn main() {}
diff --git a/tests/ui-fulldeps/auxiliary/parser.rs b/tests/ui-fulldeps/auxiliary/parser.rs
index be51bd29008..8a370512460 100644
--- a/tests/ui-fulldeps/auxiliary/parser.rs
+++ b/tests/ui-fulldeps/auxiliary/parser.rs
@@ -7,15 +7,17 @@ extern crate rustc_parse;
 extern crate rustc_session;
 extern crate rustc_span;
 
-use rustc_ast::ast::{DUMMY_NODE_ID, Expr};
-use rustc_ast::mut_visit::MutVisitor;
+use rustc_ast::ast::{AttrKind, Attribute, DUMMY_NODE_ID, Expr};
+use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::node_id::NodeId;
 use rustc_ast::ptr::P;
-use rustc_ast::token;
+use rustc_ast::token::{self, Token};
+use rustc_ast::tokenstream::{AttrTokenStream, AttrTokenTree, LazyAttrTokenStream};
 use rustc_errors::Diag;
 use rustc_parse::parser::Recovery;
 use rustc_session::parse::ParseSess;
-use rustc_span::{DUMMY_SP, FileName, Span};
+use rustc_span::{AttrId, DUMMY_SP, FileName, Span};
+use std::sync::Arc;
 
 pub fn parse_expr(psess: &ParseSess, source_code: &str) -> Option<P<Expr>> {
     let parser = rustc_parse::unwrap_or_emit_fatal(rustc_parse::new_parser_from_source_str(
@@ -46,4 +48,36 @@ impl MutVisitor for Normalize {
     fn visit_span(&mut self, span: &mut Span) {
         *span = DUMMY_SP;
     }
+
+    fn visit_attribute(&mut self, attr: &mut Attribute) {
+        attr.id = AttrId::from_u32(0);
+        if let AttrKind::Normal(normal_attr) = &mut attr.kind {
+            if let Some(tokens) = &mut normal_attr.tokens {
+                let mut stream = tokens.to_attr_token_stream();
+                normalize_attr_token_stream(&mut stream);
+                *tokens = LazyAttrTokenStream::new_direct(stream);
+            }
+        }
+        mut_visit::walk_attribute(self, attr);
+    }
+}
+
+fn normalize_attr_token_stream(stream: &mut AttrTokenStream) {
+    Arc::make_mut(&mut stream.0)
+        .iter_mut()
+        .for_each(normalize_attr_token_tree);
+}
+
+fn normalize_attr_token_tree(token: &mut AttrTokenTree) {
+    match token {
+        AttrTokenTree::Token(token, _spacing) => {
+            Normalize.visit_span(&mut token.span);
+        }
+        AttrTokenTree::Delimited(dspan, _spacing, _delim, stream) => {
+            normalize_attr_token_stream(stream);
+            Normalize.visit_span(&mut dspan.open);
+            Normalize.visit_span(&mut dspan.close);
+        }
+        AttrTokenTree::AttrsTarget(_) => unimplemented!("AttrTokenTree::AttrsTarget"),
+    }
 }
diff --git a/tests/ui-fulldeps/codegen-backend/auxiliary/the_backend.rs b/tests/ui-fulldeps/codegen-backend/auxiliary/the_backend.rs
index 656cfca1ed1..8449479287f 100644
--- a/tests/ui-fulldeps/codegen-backend/auxiliary/the_backend.rs
+++ b/tests/ui-fulldeps/codegen-backend/auxiliary/the_backend.rs
@@ -33,17 +33,10 @@ impl CodegenBackend for TheBackend {
         ""
     }
 
-    fn codegen_crate<'a, 'tcx>(
-        &self,
-        tcx: TyCtxt<'tcx>,
-        metadata: EncodedMetadata,
-        _need_metadata_module: bool,
-    ) -> Box<dyn Any> {
+    fn codegen_crate(&self, tcx: TyCtxt<'_>) -> Box<dyn Any> {
         Box::new(CodegenResults {
             modules: vec![],
             allocator_module: None,
-            metadata_module: None,
-            metadata,
             crate_info: CrateInfo::new(tcx, "fake_target_cpu".to_string()),
         })
     }
@@ -60,7 +53,13 @@ impl CodegenBackend for TheBackend {
         (*codegen_results, FxIndexMap::default())
     }
 
-    fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) {
+    fn link(
+        &self,
+        sess: &Session,
+        codegen_results: CodegenResults,
+        _metadata: EncodedMetadata,
+        outputs: &OutputFilenames,
+    ) {
         use std::io::Write;
 
         use rustc_session::config::{CrateType, OutFileName};
diff --git a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
index 36916e97856..08bed40abe8 100644
--- a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
+++ b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
@@ -88,6 +88,11 @@ static EXPRS: &[&str] = &[
     // expressions.
     "match 2 { _ => 1 - 1 }",
     "match 2 { _ => ({ 1 }) - 1 }",
+    // Expressions with an outer attr have lower precedence than expressions
+    // with an inner attr.
+    "#[attr] loop {}.field",
+    "(#[attr] loop {}).field",
+    "loop { #![attr] }.field",
     // Grammar restriction: break value starting with a labeled loop is not
     // allowed, except if the break is also labeled.
     "break 'outer 'inner: loop {} + 2",
diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr
new file mode 100644
index 00000000000..02015d2a2e5
--- /dev/null
+++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr
@@ -0,0 +1,536 @@
+error: fn_abi_of(i8) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i8,
+                       layout: Layout {
+                           size: Size(1 bytes),
+                           align: AbiAlign {
+                               abi: Align(1 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I8,
+                                       true,
+                                   ),
+                                   valid_range: 0..=255,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(1 bytes),
+                           randomization_seed: 71776123356184577,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Sext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i8,
+                   layout: Layout {
+                       size: Size(1 bytes),
+                       align: AbiAlign {
+                           abi: Align(1 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I8,
+                                   true,
+                               ),
+                               valid_range: 0..=255,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(1 bytes),
+                       randomization_seed: 71776123356184577,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: Sext,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:13:1
+   |
+LL | pub extern "sysv64" fn i8(x: i8) -> i8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u8) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u8,
+                       layout: Layout {
+                           size: Size(1 bytes),
+                           align: AbiAlign {
+                               abi: Align(1 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I8,
+                                       false,
+                                   ),
+                                   valid_range: 0..=255,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(1 bytes),
+                           randomization_seed: 71776127651151873,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Zext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u8,
+                   layout: Layout {
+                       size: Size(1 bytes),
+                       align: AbiAlign {
+                           abi: Align(1 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I8,
+                                   false,
+                               ),
+                               valid_range: 0..=255,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(1 bytes),
+                       randomization_seed: 71776127651151873,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: Zext,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:19:1
+   |
+LL | pub extern "sysv64" fn u8(x: u8) -> u8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(i16) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i16,
+                       layout: Layout {
+                           size: Size(2 bytes),
+                           align: AbiAlign {
+                               abi: Align(2 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I16,
+                                       true,
+                                   ),
+                                   valid_range: 0..=65535,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(2 bytes),
+                           randomization_seed: 18446462603027808258,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Sext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i16,
+                   layout: Layout {
+                       size: Size(2 bytes),
+                       align: AbiAlign {
+                           abi: Align(2 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I16,
+                                   true,
+                               ),
+                               valid_range: 0..=65535,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(2 bytes),
+                       randomization_seed: 18446462603027808258,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: Sext,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:25:1
+   |
+LL | pub extern "sysv64" fn i16(x: i16) -> i16 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u16) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u16,
+                       layout: Layout {
+                           size: Size(2 bytes),
+                           align: AbiAlign {
+                               abi: Align(2 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I16,
+                                       false,
+                                   ),
+                                   valid_range: 0..=65535,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(2 bytes),
+                           randomization_seed: 18446462607322775554,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Zext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u16,
+                   layout: Layout {
+                       size: Size(2 bytes),
+                       align: AbiAlign {
+                           abi: Align(2 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I16,
+                                   false,
+                               ),
+                               valid_range: 0..=65535,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(2 bytes),
+                       randomization_seed: 18446462607322775554,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: Zext,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:31:1
+   |
+LL | pub extern "sysv64" fn u16(x: u16) -> u16 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(i32) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i32,
+                       layout: Layout {
+                           size: Size(4 bytes),
+                           align: AbiAlign {
+                               abi: Align(4 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I32,
+                                       true,
+                                   ),
+                                   valid_range: 0..=4294967295,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(4 bytes),
+                           randomization_seed: 18446462603027873795,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: None,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i32,
+                   layout: Layout {
+                       size: Size(4 bytes),
+                       align: AbiAlign {
+                           abi: Align(4 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I32,
+                                   true,
+                               ),
+                               valid_range: 0..=4294967295,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(4 bytes),
+                       randomization_seed: 18446462603027873795,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:37:1
+   |
+LL | pub extern "sysv64" fn i32(x: i32) -> i32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u32) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u32,
+                       layout: Layout {
+                           size: Size(4 bytes),
+                           align: AbiAlign {
+                               abi: Align(4 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I32,
+                                       false,
+                                   ),
+                                   valid_range: 0..=4294967295,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(4 bytes),
+                           randomization_seed: 18446462607322841091,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: None,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u32,
+                   layout: Layout {
+                       size: Size(4 bytes),
+                       align: AbiAlign {
+                           abi: Align(4 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I32,
+                                   false,
+                               ),
+                               valid_range: 0..=4294967295,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(4 bytes),
+                       randomization_seed: 18446462607322841091,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:43:1
+   |
+LL | pub extern "sysv64" fn u32(x: u32) -> u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+
diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr
new file mode 100644
index 00000000000..9bb2ab45d98
--- /dev/null
+++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr
@@ -0,0 +1,536 @@
+error: fn_abi_of(i8) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i8,
+                       layout: Layout {
+                           size: Size(1 bytes),
+                           align: AbiAlign {
+                               abi: Align(1 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I8,
+                                       true,
+                                   ),
+                                   valid_range: 0..=255,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(1 bytes),
+                           randomization_seed: 71776123356184577,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Sext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i8,
+                   layout: Layout {
+                       size: Size(1 bytes),
+                       align: AbiAlign {
+                           abi: Align(1 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I8,
+                                   true,
+                               ),
+                               valid_range: 0..=255,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(1 bytes),
+                       randomization_seed: 71776123356184577,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:13:1
+   |
+LL | pub extern "sysv64" fn i8(x: i8) -> i8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u8) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u8,
+                       layout: Layout {
+                           size: Size(1 bytes),
+                           align: AbiAlign {
+                               abi: Align(1 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I8,
+                                       false,
+                                   ),
+                                   valid_range: 0..=255,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(1 bytes),
+                           randomization_seed: 71776127651151873,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Zext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u8,
+                   layout: Layout {
+                       size: Size(1 bytes),
+                       align: AbiAlign {
+                           abi: Align(1 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I8,
+                                   false,
+                               ),
+                               valid_range: 0..=255,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(1 bytes),
+                       randomization_seed: 71776127651151873,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:19:1
+   |
+LL | pub extern "sysv64" fn u8(x: u8) -> u8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(i16) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i16,
+                       layout: Layout {
+                           size: Size(2 bytes),
+                           align: AbiAlign {
+                               abi: Align(2 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I16,
+                                       true,
+                                   ),
+                                   valid_range: 0..=65535,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(2 bytes),
+                           randomization_seed: 18446462603027808258,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Sext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i16,
+                   layout: Layout {
+                       size: Size(2 bytes),
+                       align: AbiAlign {
+                           abi: Align(2 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I16,
+                                   true,
+                               ),
+                               valid_range: 0..=65535,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(2 bytes),
+                       randomization_seed: 18446462603027808258,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:25:1
+   |
+LL | pub extern "sysv64" fn i16(x: i16) -> i16 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u16) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u16,
+                       layout: Layout {
+                           size: Size(2 bytes),
+                           align: AbiAlign {
+                               abi: Align(2 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I16,
+                                       false,
+                                   ),
+                                   valid_range: 0..=65535,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(2 bytes),
+                           randomization_seed: 18446462607322775554,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: Zext,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u16,
+                   layout: Layout {
+                       size: Size(2 bytes),
+                       align: AbiAlign {
+                           abi: Align(2 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I16,
+                                   false,
+                               ),
+                               valid_range: 0..=65535,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(2 bytes),
+                       randomization_seed: 18446462607322775554,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:31:1
+   |
+LL | pub extern "sysv64" fn u16(x: u16) -> u16 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(i32) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: i32,
+                       layout: Layout {
+                           size: Size(4 bytes),
+                           align: AbiAlign {
+                               abi: Align(4 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I32,
+                                       true,
+                                   ),
+                                   valid_range: 0..=4294967295,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(4 bytes),
+                           randomization_seed: 18446462603027873795,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: None,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: i32,
+                   layout: Layout {
+                       size: Size(4 bytes),
+                       align: AbiAlign {
+                           abi: Align(4 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I32,
+                                   true,
+                               ),
+                               valid_range: 0..=4294967295,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(4 bytes),
+                       randomization_seed: 18446462603027873795,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:37:1
+   |
+LL | pub extern "sysv64" fn i32(x: i32) -> i32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: fn_abi_of(u32) = FnAbi {
+           args: [
+               ArgAbi {
+                   layout: TyAndLayout {
+                       ty: u32,
+                       layout: Layout {
+                           size: Size(4 bytes),
+                           align: AbiAlign {
+                               abi: Align(4 bytes),
+                           },
+                           backend_repr: Scalar(
+                               Initialized {
+                                   value: Int(
+                                       I32,
+                                       false,
+                                   ),
+                                   valid_range: 0..=4294967295,
+                               },
+                           ),
+                           fields: Primitive,
+                           largest_niche: None,
+                           uninhabited: false,
+                           variants: Single {
+                               index: 0,
+                           },
+                           max_repr_align: None,
+                           unadjusted_abi_align: Align(4 bytes),
+                           randomization_seed: 18446462607322841091,
+                       },
+                   },
+                   mode: Direct(
+                       ArgAttributes {
+                           regular: NoUndef,
+                           arg_ext: None,
+                           pointee_size: Size(0 bytes),
+                           pointee_align: None,
+                       },
+                   ),
+               },
+           ],
+           ret: ArgAbi {
+               layout: TyAndLayout {
+                   ty: u32,
+                   layout: Layout {
+                       size: Size(4 bytes),
+                       align: AbiAlign {
+                           abi: Align(4 bytes),
+                       },
+                       backend_repr: Scalar(
+                           Initialized {
+                               value: Int(
+                                   I32,
+                                   false,
+                               ),
+                               valid_range: 0..=4294967295,
+                           },
+                       ),
+                       fields: Primitive,
+                       largest_niche: None,
+                       uninhabited: false,
+                       variants: Single {
+                           index: 0,
+                       },
+                       max_repr_align: None,
+                       unadjusted_abi_align: Align(4 bytes),
+                       randomization_seed: 18446462607322841091,
+                   },
+               },
+               mode: Direct(
+                   ArgAttributes {
+                       regular: NoUndef,
+                       arg_ext: None,
+                       pointee_size: Size(0 bytes),
+                       pointee_align: None,
+                   },
+               ),
+           },
+           c_variadic: false,
+           fixed_count: 1,
+           conv: X86(
+               SysV64,
+           ),
+           can_unwind: false,
+       }
+  --> $DIR/x86-64-sysv64-arg-ext.rs:43:1
+   |
+LL | pub extern "sysv64" fn u32(x: u32) -> u32 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+
diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.rs b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.rs
new file mode 100644
index 00000000000..29a3061cfd0
--- /dev/null
+++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.rs
@@ -0,0 +1,46 @@
+//@ only-x86_64
+//@ revisions: apple other
+//@[apple] only-apple
+//@[other] ignore-apple
+
+// Apple targets extend up to 32 bits for both arguments and returns, other targets only extend
+// arguments.
+
+#![crate_type = "lib"]
+#![feature(rustc_attrs)]
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn i8(x: i8) -> i8 {
+    //~^ ERROR fn_abi_of(i8)
+    x
+}
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn u8(x: u8) -> u8 {
+    //~^ ERROR fn_abi_of(u8)
+    x
+}
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn i16(x: i16) -> i16 {
+    //~^ ERROR fn_abi_of(i16)
+    x
+}
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn u16(x: u16) -> u16 {
+    //~^ ERROR fn_abi_of(u16)
+    x
+}
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn i32(x: i32) -> i32 {
+    //~^ ERROR fn_abi_of(i32)
+    x
+}
+
+#[rustc_abi(debug)]
+pub extern "sysv64" fn u32(x: u32) -> u32 {
+    //~^ ERROR fn_abi_of(u32)
+    x
+}
diff --git a/tests/ui/async-await/async-drop/async-drop-initial.rs b/tests/ui/async-await/async-drop/async-drop-initial.rs
index 263b70699f5..cd33c143fba 100644
--- a/tests/ui/async-await/async-drop/async-drop-initial.rs
+++ b/tests/ui/async-await/async-drop/async-drop-initial.rs
@@ -62,7 +62,7 @@ fn main() {
         test_async_drop(&j, 16).await;
         test_async_drop(
             AsyncStruct { b: AsyncInt(8), a: AsyncInt(7), i: 6 },
-            if cfg!(panic = "unwind") { 168 } else { 136 },
+            136,
         ).await;
         test_async_drop(ManuallyDrop::new(AsyncInt(9)), 16).await;
 
diff --git a/tests/crashes/140429.rs b/tests/ui/async-await/async-drop/live-dead-storage.rs
index 041eaf86c5c..e6f25d351c3 100644
--- a/tests/crashes/140429.rs
+++ b/tests/ui/async-await/async-drop/live-dead-storage.rs
@@ -1,6 +1,9 @@
-//@ known-bug: #140429
+// ex-ice: #140429
 //@ compile-flags: -Zlint-mir --crate-type lib
 //@ edition:2024
+//@ check-pass
 
 #![feature(async_drop)]
+#![allow(incomplete_features)]
+
 async fn a<T>(x: T) {}
diff --git a/tests/crashes/140531.rs b/tests/ui/async-await/async-drop/live-dead-storage2.rs
index f664481d440..18df870785e 100644
--- a/tests/crashes/140531.rs
+++ b/tests/ui/async-await/async-drop/live-dead-storage2.rs
@@ -1,7 +1,11 @@
-//@ known-bug: #140531
-//@compile-flags: -Zlint-mir --crate-type lib
+// ex-ice: #140531
+//@ compile-flags: -Zlint-mir --crate-type lib
 //@ edition:2024
+//@ check-pass
+
 #![feature(async_drop)]
+#![allow(incomplete_features)]
+
 async fn call_once(f: impl AsyncFnOnce()) {
     let fut = Box::pin(f());
 }
diff --git a/tests/ui/async-await/async-drop/live-dead-storage3.rs b/tests/ui/async-await/async-drop/live-dead-storage3.rs
new file mode 100644
index 00000000000..d9fba5759f7
--- /dev/null
+++ b/tests/ui/async-await/async-drop/live-dead-storage3.rs
@@ -0,0 +1,56 @@
+// ex-ice: #141761
+//@ compile-flags: -Zlint-mir --crate-type lib
+//@ edition:2024
+//@ check-pass
+
+#![feature(async_drop)]
+#![allow(incomplete_features)]
+
+type BoxFuture<T> = std::pin::Pin<Box<dyn Future<Output = T>>>;
+fn main() {}
+async fn f() {
+    run("").await
+}
+struct InMemoryStorage;
+struct User<'dep> {
+    dep: &'dep str,
+}
+impl<'a> StorageRequest<InMemoryStorage> for SaveUser<'a> {
+    fn execute(&self) -> BoxFuture<Result<(), String>> {
+        todo!()
+    }
+}
+trait Storage {
+    type Error;
+}
+impl Storage for InMemoryStorage {
+    type Error = String;
+}
+trait StorageRequestReturnType {
+    type Output;
+}
+trait StorageRequest<S: Storage>: StorageRequestReturnType {
+    fn execute(&self) -> BoxFuture<Result<<Self>::Output, S::Error>>;
+}
+struct SaveUser<'a> {
+    name: &'a str,
+}
+impl<'a> StorageRequestReturnType for SaveUser<'a> {
+    type Output = ();
+}
+impl<'dep> User<'dep> {
+    async fn save<S>(self)
+    where
+        S: Storage,
+        for<'a> SaveUser<'a>: StorageRequest<S>,
+    {
+        SaveUser { name: "" }.execute().await;
+    }
+}
+async fn run<S>(dep: &str)
+where
+    S: Storage,
+    for<'a> SaveUser<'a>: StorageRequest<S>,
+{
+    User { dep }.save().await
+}
diff --git a/tests/ui/async-await/async-drop/live-dead-storage4.rs b/tests/ui/async-await/async-drop/live-dead-storage4.rs
new file mode 100644
index 00000000000..d927cb96674
--- /dev/null
+++ b/tests/ui/async-await/async-drop/live-dead-storage4.rs
@@ -0,0 +1,56 @@
+// ex-ice: #141409
+//@ compile-flags: -Zmir-enable-passes=+Inline -Zvalidate-mir -Zlint-mir --crate-type lib
+//@ edition:2024
+//@ check-pass
+
+#![feature(async_drop)]
+#![allow(incomplete_features)]
+#![allow(non_snake_case)]
+
+use std::mem::ManuallyDrop;
+use std::{
+    future::{async_drop_in_place, Future},
+    pin::{pin, Pin},
+    sync::{mpsc, Arc},
+    task::{Context, Poll, Wake, Waker},
+};
+fn main() {
+    block_on(bar(0))
+}
+async fn baz(ident_base: usize) {}
+async fn bar(ident_base: usize) {
+    baz(1).await
+}
+fn block_on<F>(fut_unpin: F) -> F::Output
+where
+    F: Future,
+{
+    let fut_pin = pin!(ManuallyDrop::new(fut_unpin));
+    let mut fut = unsafe { Pin::map_unchecked_mut(fut_pin, |x| &mut **x) };
+    let (waker, rx) = simple_waker();
+    let mut context = Context::from_waker(&waker);
+    let rv = loop {
+        match fut.as_mut().poll(&mut context) {
+            Poll::Ready(out) => break out,
+            PollPending => (),
+        }
+    };
+    let drop_fut_unpin = unsafe { async_drop_in_place(fut.get_unchecked_mut()) };
+    let drop_fut = pin!(drop_fut_unpin);
+    loop {
+        match drop_fut.poll(&mut context) {
+            Poll => break,
+        }
+    }
+    rv
+}
+fn simple_waker() -> (Waker, mpsc::Receiver<()>) {
+    struct SimpleWaker {
+        tx: mpsc::Sender<()>,
+    }
+    impl Wake for SimpleWaker {
+        fn wake(self: Arc<Self>) {}
+    }
+    let (tx, rx) = mpsc::channel();
+    (Waker::from(Arc::new(SimpleWaker { tx })), rx)
+}
diff --git a/tests/ui/borrowck/span-semicolon-issue-139049.fixed b/tests/ui/borrowck/span-semicolon-issue-139049.fixed
new file mode 100644
index 00000000000..0b263b22296
--- /dev/null
+++ b/tests/ui/borrowck/span-semicolon-issue-139049.fixed
@@ -0,0 +1,52 @@
+// Make sure the generated suggestion suggest editing the user
+// code instead of the std macro implementation
+
+//@ run-rustfix
+
+#![allow(dead_code)]
+
+use std::fmt::{self, Display};
+
+struct Mutex;
+
+impl Mutex {
+    fn lock(&self) -> MutexGuard<'_> {
+        MutexGuard(self)
+    }
+}
+
+struct MutexGuard<'a>(&'a Mutex);
+
+impl<'a> Drop for MutexGuard<'a> {
+    fn drop(&mut self) {}
+}
+
+struct Out;
+
+impl Out {
+    fn write_fmt(&self, _args: fmt::Arguments) {}
+}
+
+impl<'a> Display for MutexGuard<'a> {
+    fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
+        Ok(())
+    }
+}
+
+fn main() {
+    let _write = {
+        let mutex = Mutex;
+        write!(Out, "{}", mutex.lock());
+        //~^ ERROR `mutex` does not live long enough
+        //~| SUGGESTION ;
+    };
+
+    let _write = {
+        use std::io::Write as _;
+
+        let mutex = Mutex;
+        let x = write!(std::io::stdout(), "{}", mutex.lock()); x
+        //~^ ERROR `mutex` does not live long enough
+        //~| SUGGESTION let x
+    };
+}
diff --git a/tests/ui/borrowck/span-semicolon-issue-139049.rs b/tests/ui/borrowck/span-semicolon-issue-139049.rs
new file mode 100644
index 00000000000..a92742ac94b
--- /dev/null
+++ b/tests/ui/borrowck/span-semicolon-issue-139049.rs
@@ -0,0 +1,52 @@
+// Make sure the generated suggestion suggest editing the user
+// code instead of the std macro implementation
+
+//@ run-rustfix
+
+#![allow(dead_code)]
+
+use std::fmt::{self, Display};
+
+struct Mutex;
+
+impl Mutex {
+    fn lock(&self) -> MutexGuard<'_> {
+        MutexGuard(self)
+    }
+}
+
+struct MutexGuard<'a>(&'a Mutex);
+
+impl<'a> Drop for MutexGuard<'a> {
+    fn drop(&mut self) {}
+}
+
+struct Out;
+
+impl Out {
+    fn write_fmt(&self, _args: fmt::Arguments) {}
+}
+
+impl<'a> Display for MutexGuard<'a> {
+    fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
+        Ok(())
+    }
+}
+
+fn main() {
+    let _write = {
+        let mutex = Mutex;
+        write!(Out, "{}", mutex.lock())
+        //~^ ERROR `mutex` does not live long enough
+        //~| SUGGESTION ;
+    };
+
+    let _write = {
+        use std::io::Write as _;
+
+        let mutex = Mutex;
+        write!(std::io::stdout(), "{}", mutex.lock())
+        //~^ ERROR `mutex` does not live long enough
+        //~| SUGGESTION let x
+    };
+}
diff --git a/tests/ui/borrowck/span-semicolon-issue-139049.stderr b/tests/ui/borrowck/span-semicolon-issue-139049.stderr
new file mode 100644
index 00000000000..123bdf4bc67
--- /dev/null
+++ b/tests/ui/borrowck/span-semicolon-issue-139049.stderr
@@ -0,0 +1,47 @@
+error[E0597]: `mutex` does not live long enough
+  --> $DIR/span-semicolon-issue-139049.rs:39:27
+   |
+LL |         let mutex = Mutex;
+   |             ----- binding `mutex` declared here
+LL |         write!(Out, "{}", mutex.lock())
+   |                           ^^^^^-------
+   |                           |
+   |                           borrowed value does not live long enough
+   |                           a temporary with access to the borrow is created here ...
+...
+LL |     };
+   |     -- ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `MutexGuard`
+   |     |
+   |     `mutex` dropped here while still borrowed
+   |
+help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
+   |
+LL |         write!(Out, "{}", mutex.lock());
+   |                                        +
+
+error[E0597]: `mutex` does not live long enough
+  --> $DIR/span-semicolon-issue-139049.rs:48:41
+   |
+LL |         let mutex = Mutex;
+   |             ----- binding `mutex` declared here
+LL |         write!(std::io::stdout(), "{}", mutex.lock())
+   |                                         ^^^^^-------
+   |                                         |
+   |                                         borrowed value does not live long enough
+   |                                         a temporary with access to the borrow is created here ...
+...
+LL |     };
+   |     -- ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `MutexGuard`
+   |     |
+   |     `mutex` dropped here while still borrowed
+   |
+   = note: the temporary is part of an expression at the end of a block;
+           consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
+help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
+   |
+LL |         let x = write!(std::io::stdout(), "{}", mutex.lock()); x
+   |         +++++++                                              +++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/tests/ui/editions/never-type-fallback-breaking.e2021.stderr b/tests/ui/editions/never-type-fallback-breaking.e2021.stderr
index 4ca17918827..6b84a64fffe 100644
--- a/tests/ui/editions/never-type-fallback-breaking.e2021.stderr
+++ b/tests/ui/editions/never-type-fallback-breaking.e2021.stderr
@@ -96,3 +96,108 @@ LL |     takes_apit2(mk::<()>()?);
 
 warning: 5 warnings emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:18:1
+   |
+LL | fn m() {
+   | ^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:22:17
+   |
+LL |         true => Default::default(),
+   |                 ^^^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     let x: () = match true {
+   |          ++++
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:30:1
+   |
+LL | fn q() -> Option<()> {
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:37:5
+   |
+LL |     deserialize()?;
+   |     ^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     deserialize::<()>()?;
+   |                ++++++
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:47:1
+   |
+LL | fn meow() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `(): From<!>` will fail
+  --> $DIR/never-type-fallback-breaking.rs:50:5
+   |
+LL |     help(1)?;
+   |     ^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     help::<(), _>(1)?;
+   |         +++++++++
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:59:1
+   |
+LL | pub fn fallback_return() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:62:19
+   |
+LL |     takes_apit(|| Default::default())?;
+   |                   ^^^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     takes_apit::<()>(|| Default::default())?;
+   |               ++++++
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/never-type-fallback-breaking.rs:73:1
+   |
+LL | fn fully_apit() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/never-type-fallback-breaking.rs:76:17
+   |
+LL |     takes_apit2(mk()?);
+   |                 ^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     takes_apit2(mk::<()>()?);
+   |                   ++++++
+
diff --git a/tests/ui/lint/wasm_c_abi_transition.rs b/tests/ui/lint/wasm_c_abi_transition.rs
deleted file mode 100644
index 411772ae890..00000000000
--- a/tests/ui/lint/wasm_c_abi_transition.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-//@ compile-flags: --target wasm32-unknown-unknown
-//@ needs-llvm-components: webassembly
-//@ add-core-stubs
-//@ build-fail
-
-#![feature(no_core, repr_simd)]
-#![no_core]
-#![crate_type = "lib"]
-#![deny(wasm_c_abi)]
-
-extern crate minicore;
-use minicore::*;
-
-pub extern "C" fn my_fun_trivial(_x: i32, _y: f32) {}
-
-#[repr(C)]
-pub struct MyType(i32, i32);
-pub extern "C" fn my_fun(_x: MyType) {} //~ERROR: wasm ABI transition
-//~^WARN: previously accepted
-
-// This one is ABI-safe as it only wraps a single field,
-// and the return type can be anything.
-#[repr(C)]
-pub struct MySafeType(i32);
-pub extern "C" fn my_fun_safe(_x: MySafeType) -> MyType { loop {} }
-
-// This one not ABI-safe due to the alignment.
-#[repr(C, align(16))]
-pub struct MyAlignedType(i32);
-pub extern "C" fn my_fun_aligned(_x: MyAlignedType) {} //~ERROR: wasm ABI transition
-//~^WARN: previously accepted
-
-// Check call-site warning
-extern "C" {
-    fn other_fun(x: MyType);
-}
-
-pub fn call_other_fun(x: MyType) {
-    unsafe { other_fun(x) } //~ERROR: wasm ABI transition
-    //~^WARN: previously accepted
-}
-
-// Zero-sized types are safe in both ABIs
-#[repr(C)]
-pub struct MyZstType;
-#[allow(improper_ctypes_definitions)]
-pub extern "C" fn zst_safe(_x: (), _y: MyZstType) {}
-
-// The old and new wasm ABI treats simd types like `v128` the same way, so no
-// wasm_c_abi warning should be emitted.
-#[repr(simd)]
-#[allow(non_camel_case_types)]
-pub struct v128([i32; 4]);
-#[target_feature(enable = "simd128")]
-pub extern "C" fn my_safe_simd(x: v128) -> v128 { x }
-//~^ WARN `extern` fn uses type `v128`, which is not FFI-safe
-//~| WARN `extern` fn uses type `v128`, which is not FFI-safe
diff --git a/tests/ui/lint/wasm_c_abi_transition.stderr b/tests/ui/lint/wasm_c_abi_transition.stderr
deleted file mode 100644
index b4526bf8d68..00000000000
--- a/tests/ui/lint/wasm_c_abi_transition.stderr
+++ /dev/null
@@ -1,114 +0,0 @@
-warning: `extern` fn uses type `v128`, which is not FFI-safe
-  --> $DIR/wasm_c_abi_transition.rs:55:35
-   |
-LL | pub extern "C" fn my_safe_simd(x: v128) -> v128 { x }
-   |                                   ^^^^ not FFI-safe
-   |
-   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
-   = note: this struct has unspecified layout
-note: the type is defined here
-  --> $DIR/wasm_c_abi_transition.rs:53:1
-   |
-LL | pub struct v128([i32; 4]);
-   | ^^^^^^^^^^^^^^^
-   = note: `#[warn(improper_ctypes_definitions)]` on by default
-
-warning: `extern` fn uses type `v128`, which is not FFI-safe
-  --> $DIR/wasm_c_abi_transition.rs:55:44
-   |
-LL | pub extern "C" fn my_safe_simd(x: v128) -> v128 { x }
-   |                                            ^^^^ not FFI-safe
-   |
-   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
-   = note: this struct has unspecified layout
-note: the type is defined here
-  --> $DIR/wasm_c_abi_transition.rs:53:1
-   |
-LL | pub struct v128([i32; 4]);
-   | ^^^^^^^^^^^^^^^
-
-error: this function definition involves an argument of type `MyType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:18:1
-   |
-LL | pub extern "C" fn my_fun(_x: MyType) {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-note: the lint level is defined here
-  --> $DIR/wasm_c_abi_transition.rs:9:9
-   |
-LL | #![deny(wasm_c_abi)]
-   |         ^^^^^^^^^^
-
-error: this function definition involves an argument of type `MyAlignedType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:30:1
-   |
-LL | pub extern "C" fn my_fun_aligned(_x: MyAlignedType) {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-
-error: this function call involves an argument of type `MyType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:39:14
-   |
-LL |     unsafe { other_fun(x) }
-   |              ^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-
-error: aborting due to 3 previous errors; 2 warnings emitted
-
-Future incompatibility report: Future breakage diagnostic:
-error: this function definition involves an argument of type `MyType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:18:1
-   |
-LL | pub extern "C" fn my_fun(_x: MyType) {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-note: the lint level is defined here
-  --> $DIR/wasm_c_abi_transition.rs:9:9
-   |
-LL | #![deny(wasm_c_abi)]
-   |         ^^^^^^^^^^
-
-Future breakage diagnostic:
-error: this function definition involves an argument of type `MyAlignedType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:30:1
-   |
-LL | pub extern "C" fn my_fun_aligned(_x: MyAlignedType) {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-note: the lint level is defined here
-  --> $DIR/wasm_c_abi_transition.rs:9:9
-   |
-LL | #![deny(wasm_c_abi)]
-   |         ^^^^^^^^^^
-
-Future breakage diagnostic:
-error: this function call involves an argument of type `MyType` which is affected by the wasm ABI transition
-  --> $DIR/wasm_c_abi_transition.rs:39:14
-   |
-LL |     unsafe { other_fun(x) }
-   |              ^^^^^^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #138762 <https://github.com/rust-lang/rust/issues/138762>
-   = help: the "C" ABI Rust uses on wasm32-unknown-unknown will change to align with the standard "C" ABI for this target
-note: the lint level is defined here
-  --> $DIR/wasm_c_abi_transition.rs:9:9
-   |
-LL | #![deny(wasm_c_abi)]
-   |         ^^^^^^^^^^
-
diff --git a/tests/ui/macros/format-args-temporaries-in-write.stderr b/tests/ui/macros/format-args-temporaries-in-write.stderr
index e05246cfbe3..e58a43383f6 100644
--- a/tests/ui/macros/format-args-temporaries-in-write.stderr
+++ b/tests/ui/macros/format-args-temporaries-in-write.stderr
@@ -14,6 +14,10 @@ LL |     };
    |     |
    |     `mutex` dropped here while still borrowed
    |
+help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
+   |
+LL |         write!(Out, "{}", mutex.lock()); /* no semicolon */
+   |                                        +
 
 error[E0597]: `mutex` does not live long enough
   --> $DIR/format-args-temporaries-in-write.rs:47:29
@@ -31,6 +35,10 @@ LL |     };
    |     |
    |     `mutex` dropped here while still borrowed
    |
+help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
+   |
+LL |         writeln!(Out, "{}", mutex.lock()); /* no semicolon */
+   |                                          +
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/never_type/defaulted-never-note.nofallback.stderr b/tests/ui/never_type/defaulted-never-note.nofallback.stderr
index 2abff61fa54..6de323ad12c 100644
--- a/tests/ui/never_type/defaulted-never-note.nofallback.stderr
+++ b/tests/ui/never_type/defaulted-never-note.nofallback.stderr
@@ -20,3 +20,24 @@ LL |     let _x: () = return;
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/defaulted-never-note.rs:28:1
+   |
+LL | fn smeg() {
+   | ^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: ImplementedForUnitButNotNever` will fail
+  --> $DIR/defaulted-never-note.rs:32:9
+   |
+LL |     foo(_x);
+   |         ^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     let _x: () = return;
+   |           ++++
+
diff --git a/tests/ui/never_type/dependency-on-fallback-to-unit.stderr b/tests/ui/never_type/dependency-on-fallback-to-unit.stderr
index bf37cc7b4b4..be8075662e0 100644
--- a/tests/ui/never_type/dependency-on-fallback-to-unit.stderr
+++ b/tests/ui/never_type/dependency-on-fallback-to-unit.stderr
@@ -40,3 +40,46 @@ LL |     deserialize::<()>()?;
 
 warning: 2 warnings emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/dependency-on-fallback-to-unit.rs:8:1
+   |
+LL | fn def() {
+   | ^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/dependency-on-fallback-to-unit.rs:12:19
+   |
+LL |         false => <_>::default(),
+   |                   ^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL -         false => <_>::default(),
+LL +         false => <()>::default(),
+   |
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/dependency-on-fallback-to-unit.rs:19:1
+   |
+LL | fn question_mark() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/dependency-on-fallback-to-unit.rs:22:5
+   |
+LL |     deserialize()?;
+   |     ^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     deserialize::<()>()?;
+   |                ++++++
+
diff --git a/tests/ui/never_type/diverging-fallback-control-flow.nofallback.stderr b/tests/ui/never_type/diverging-fallback-control-flow.nofallback.stderr
index 4b8a5d5e934..44ebdb43510 100644
--- a/tests/ui/never_type/diverging-fallback-control-flow.nofallback.stderr
+++ b/tests/ui/never_type/diverging-fallback-control-flow.nofallback.stderr
@@ -39,3 +39,45 @@ LL |     let x: ();
 
 warning: 2 warnings emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/diverging-fallback-control-flow.rs:30:1
+   |
+LL | fn assignment() {
+   | ^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: UnitDefault` will fail
+  --> $DIR/diverging-fallback-control-flow.rs:36:13
+   |
+LL |         x = UnitDefault::default();
+   |             ^^^^^^^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     let x: ();
+   |          ++++
+
+Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/diverging-fallback-control-flow.rs:42:1
+   |
+LL | fn assignment_rev() {
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: UnitDefault` will fail
+  --> $DIR/diverging-fallback-control-flow.rs:50:13
+   |
+LL |         x = UnitDefault::default();
+   |             ^^^^^^^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     let x: ();
+   |          ++++
+
diff --git a/tests/ui/never_type/diverging-fallback-no-leak.nofallback.stderr b/tests/ui/never_type/diverging-fallback-no-leak.nofallback.stderr
index 94af02a3698..4a8dea42a4d 100644
--- a/tests/ui/never_type/diverging-fallback-no-leak.nofallback.stderr
+++ b/tests/ui/never_type/diverging-fallback-no-leak.nofallback.stderr
@@ -20,3 +20,24 @@ LL |     unconstrained_arg::<()>(return);
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/diverging-fallback-no-leak.rs:14:1
+   |
+LL | fn main() {
+   | ^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Test` will fail
+  --> $DIR/diverging-fallback-no-leak.rs:20:23
+   |
+LL |     unconstrained_arg(return);
+   |                       ^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     unconstrained_arg::<()>(return);
+   |                      ++++++
+
diff --git a/tests/ui/never_type/diverging-fallback-unconstrained-return.nofallback.stderr b/tests/ui/never_type/diverging-fallback-unconstrained-return.nofallback.stderr
index 22349d39857..803af39fd86 100644
--- a/tests/ui/never_type/diverging-fallback-unconstrained-return.nofallback.stderr
+++ b/tests/ui/never_type/diverging-fallback-unconstrained-return.nofallback.stderr
@@ -20,3 +20,24 @@ LL |     let _: () = if true { unconstrained_return() } else { panic!() };
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/diverging-fallback-unconstrained-return.rs:28:1
+   |
+LL | fn main() {
+   | ^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: UnitReturn` will fail
+  --> $DIR/diverging-fallback-unconstrained-return.rs:39:23
+   |
+LL |     let _ = if true { unconstrained_return() } else { panic!() };
+   |                       ^^^^^^^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     let _: () = if true { unconstrained_return() } else { panic!() };
+   |          ++++
+
diff --git a/tests/ui/never_type/dont-suggest-turbofish-from-expansion.stderr b/tests/ui/never_type/dont-suggest-turbofish-from-expansion.stderr
index 3fe642a8401..365e8869897 100644
--- a/tests/ui/never_type/dont-suggest-turbofish-from-expansion.stderr
+++ b/tests/ui/never_type/dont-suggest-turbofish-from-expansion.stderr
@@ -24,3 +24,28 @@ LL |         let created: () = create_ok_default()?;
 
 error: aborting due to 1 previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: this function depends on never type fallback being `()`
+  --> $DIR/dont-suggest-turbofish-from-expansion.rs:10:1
+   |
+LL | fn main() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/dont-suggest-turbofish-from-expansion.rs:14:23
+   |
+LL |         let created = create_ok_default()?;
+   |                       ^^^^^^^^^^^^^^^^^^^
+note: the lint level is defined here
+  --> $DIR/dont-suggest-turbofish-from-expansion.rs:1:9
+   |
+LL | #![deny(dependency_on_unit_never_type_fallback)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let created: () = create_ok_default()?;
+   |                    ++++
+
diff --git a/tests/ui/never_type/fallback-closure-ret.nofallback.stderr b/tests/ui/never_type/fallback-closure-ret.nofallback.stderr
index d7463be6acc..cf19363a7d8 100644
--- a/tests/ui/never_type/fallback-closure-ret.nofallback.stderr
+++ b/tests/ui/never_type/fallback-closure-ret.nofallback.stderr
@@ -20,3 +20,24 @@ LL |     foo::<()>(|| panic!());
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/fallback-closure-ret.rs:21:1
+   |
+LL | fn main() {
+   | ^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Bar` will fail
+  --> $DIR/fallback-closure-ret.rs:24:5
+   |
+LL |     foo(|| panic!());
+   |     ^^^^^^^^^^^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     foo::<()>(|| panic!());
+   |        ++++++
+
diff --git a/tests/ui/never_type/impl_trait_fallback.stderr b/tests/ui/never_type/impl_trait_fallback.stderr
index 72788a64888..7250db127cd 100644
--- a/tests/ui/never_type/impl_trait_fallback.stderr
+++ b/tests/ui/never_type/impl_trait_fallback.stderr
@@ -16,3 +16,20 @@ LL | fn should_ret_unit() -> impl T {
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: this function depends on never type fallback being `()`
+  --> $DIR/impl_trait_fallback.rs:8:1
+   |
+LL | fn should_ret_unit() -> impl T {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: T` will fail
+  --> $DIR/impl_trait_fallback.rs:8:25
+   |
+LL | fn should_ret_unit() -> impl T {
+   |                         ^^^^^^
+   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
+
diff --git a/tests/ui/never_type/lint-breaking-2024-assign-underscore.stderr b/tests/ui/never_type/lint-breaking-2024-assign-underscore.stderr
index 86786c3bfe0..945db40782e 100644
--- a/tests/ui/never_type/lint-breaking-2024-assign-underscore.stderr
+++ b/tests/ui/never_type/lint-breaking-2024-assign-underscore.stderr
@@ -24,3 +24,28 @@ LL |     _ = foo::<()>()?;
 
 error: aborting due to 1 previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: this function depends on never type fallback being `()`
+  --> $DIR/lint-breaking-2024-assign-underscore.rs:10:1
+   |
+LL | fn test() -> Result<(), ()> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the types explicitly
+note: in edition 2024, the requirement `!: Default` will fail
+  --> $DIR/lint-breaking-2024-assign-underscore.rs:13:9
+   |
+LL |     _ = foo()?;
+   |         ^^^^^
+note: the lint level is defined here
+  --> $DIR/lint-breaking-2024-assign-underscore.rs:4:9
+   |
+LL | #![deny(dependency_on_unit_never_type_fallback)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: use `()` annotations to avoid fallback changes
+   |
+LL |     _ = foo::<()>()?;
+   |            ++++++
+
diff --git a/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2015.stderr b/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2015.stderr
index 49b966f32ce..c90efd27784 100644
--- a/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2015.stderr
+++ b/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2015.stderr
@@ -133,3 +133,155 @@ LL |         msg_send!();
 
 warning: 10 warnings emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:12:18
+   |
+LL |         unsafe { mem::zeroed() }
+   |                  ^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { mem::zeroed::<()>() }
+   |                             ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:29:13
+   |
+LL |             core::mem::transmute(Zst)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |             core::mem::transmute::<_, ()>(Zst)
+   |                                 +++++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this union access
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:46:18
+   |
+LL |         unsafe { Union { a: () }.b }
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+
+Future breakage diagnostic:
+warning: never type fallback affects this raw pointer dereference
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:57:18
+   |
+LL |         unsafe { *ptr::from_ref(&()).cast() }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { *ptr::from_ref(&()).cast::<()>() }
+   |                                          ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:78:18
+   |
+LL |         unsafe { internally_create(x) }
+   |                  ^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { internally_create::<()>(x) }
+   |                                   ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:96:18
+   |
+LL |         unsafe { zeroed() }
+   |                  ^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let zeroed = mem::zeroed::<()>;
+   |                                 ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:91:22
+   |
+LL |         let zeroed = mem::zeroed;
+   |                      ^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let zeroed = mem::zeroed::<()>;
+   |                                 ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:114:17
+   |
+LL |         let f = internally_create;
+   |                 ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let f = internally_create::<()>;
+   |                                  ++++++
+
+Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` method
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:139:13
+   |
+LL |             S(marker::PhantomData).create_out_of_thin_air()
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+
+Future breakage diagnostic:
+warning: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:157:19
+   |
+LL |             match send_message::<_ /* ?0 */>() {
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |         msg_send!();
+   |         ----------- in this macro invocation
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
+   = note: this warning originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2024.stderr b/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2024.stderr
index 4d3692a7b04..858d7381eed 100644
--- a/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2024.stderr
+++ b/tests/ui/never_type/lint-never-type-fallback-flowing-into-unsafe.e2024.stderr
@@ -142,3 +142,155 @@ LL |         unsafe { mem::zeroed() }
 
 error: aborting due to 10 previous errors; 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:12:18
+   |
+LL |         unsafe { mem::zeroed() }
+   |                  ^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { mem::zeroed::<()>() }
+   |                             ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:29:13
+   |
+LL |             core::mem::transmute(Zst)
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |             core::mem::transmute::<_, ()>(Zst)
+   |                                 +++++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this union access
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:46:18
+   |
+LL |         unsafe { Union { a: () }.b }
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+
+Future breakage diagnostic:
+error: never type fallback affects this raw pointer dereference
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:57:18
+   |
+LL |         unsafe { *ptr::from_ref(&()).cast() }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { *ptr::from_ref(&()).cast::<()>() }
+   |                                          ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:78:18
+   |
+LL |         unsafe { internally_create(x) }
+   |                  ^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         unsafe { internally_create::<()>(x) }
+   |                                   ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:96:18
+   |
+LL |         unsafe { zeroed() }
+   |                  ^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let zeroed = mem::zeroed::<()>;
+   |                                 ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:91:22
+   |
+LL |         let zeroed = mem::zeroed;
+   |                      ^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let zeroed = mem::zeroed::<()>;
+   |                                 ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:114:17
+   |
+LL |         let f = internally_create;
+   |                 ^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+help: use `()` annotations to avoid fallback changes
+   |
+LL |         let f = internally_create::<()>;
+   |                                  ++++++
+
+Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` method
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:139:13
+   |
+LL |             S(marker::PhantomData).create_out_of_thin_air()
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+
+Future breakage diagnostic:
+error: never type fallback affects this call to an `unsafe` function
+  --> $DIR/lint-never-type-fallback-flowing-into-unsafe.rs:157:19
+   |
+LL |             match send_message::<_ /* ?0 */>() {
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |         msg_send!();
+   |         ----------- in this macro invocation
+   |
+   = warning: this changes meaning in Rust 2024 and in a future release in all editions!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html>
+   = help: specify the type explicitly
+   = note: `#[deny(never_type_fallback_flowing_into_unsafe)]` on by default
+   = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)
+