diff --git a/Cargo.lock b/Cargo.lock
index 1a7d7e3f5d7..0b5aa7db319 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -771,7 +771,7 @@ dependencies = [
  "tracing-subscriber",
  "unified-diff",
  "walkdir",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -1713,7 +1713,7 @@ dependencies = [
  "iana-time-zone-haiku",
  "js-sys",
  "wasm-bindgen",
- "windows-core",
+ "windows-core 0.52.0",
 ]
 
 [[package]]
@@ -2436,15 +2436,6 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
-[[package]]
-name = "ntapi"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8a3895c6391c39d7fe7ebc444a87eb2991b2a0bc718fdabd071eec617fc68e4"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "nu-ansi-term"
 version = "0.46.0"
@@ -3717,7 +3708,7 @@ dependencies = [
  "thorin-dwp",
  "tracing",
  "wasm-encoder 0.210.0",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -3774,7 +3765,7 @@ dependencies = [
  "tempfile",
  "thin-vec",
  "tracing",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -3835,7 +3826,7 @@ dependencies = [
  "shlex",
  "time",
  "tracing",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -3886,7 +3877,7 @@ dependencies = [
  "termcolor",
  "termize",
  "tracing",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -4355,6 +4346,7 @@ dependencies = [
  "rustc_span",
  "rustc_target",
  "rustc_trait_selection",
+ "rustc_type_ir",
  "smallvec",
  "tracing",
 ]
@@ -4607,7 +4599,7 @@ dependencies = [
  "smallvec",
  "termize",
  "tracing",
- "windows",
+ "windows 0.52.0",
 ]
 
 [[package]]
@@ -5365,16 +5357,13 @@ dependencies = [
 
 [[package]]
 name = "sysinfo"
-version = "0.30.12"
+version = "0.31.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "732ffa00f53e6b2af46208fba5718d9662a421049204e156328b66791ffa15ae"
+checksum = "d4115055da5f572fff541dd0c4e61b0262977f453cc9fe04be83aba25a89bdab"
 dependencies = [
- "cfg-if",
  "core-foundation-sys",
  "libc",
- "ntapi",
- "once_cell",
- "windows",
+ "windows 0.57.0",
 ]
 
 [[package]]
@@ -6299,7 +6288,17 @@ version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e48a53791691ab099e5e2ad123536d0fff50652600abaf43bbf952894110d0be"
 dependencies = [
- "windows-core",
+ "windows-core 0.52.0",
+ "windows-targets 0.52.5",
+]
+
+[[package]]
+name = "windows"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12342cb4d8e3b046f3d80effd474a7a02447231330ef77d71daa6fbc40681143"
+dependencies = [
+ "windows-core 0.57.0",
  "windows-targets 0.52.5",
 ]
 
@@ -6326,12 +6325,55 @@ dependencies = [
  "windows-targets 0.52.5",
 ]
 
+[[package]]
+name = "windows-core"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2ed2439a290666cd67ecce2b0ffaad89c2a56b976b736e6ece670297897832d"
+dependencies = [
+ "windows-implement",
+ "windows-interface",
+ "windows-result",
+ "windows-targets 0.52.5",
+]
+
+[[package]]
+name = "windows-implement"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9107ddc059d5b6fbfbffdfa7a7fe3e22a226def0b2608f72e9d552763d3e1ad7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.67",
+]
+
+[[package]]
+name = "windows-interface"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29bee4b38ea3cde66011baa44dba677c432a78593e202392d1e9070cf2a7fca7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.67",
+]
+
 [[package]]
 name = "windows-metadata"
 version = "0.58.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2e837f3c3012cfe9e7086302a93f441a7999439be1ad4c530d55d2f6d2921809"
 
+[[package]]
+name = "windows-result"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e383302e8ec8515204254685643de10811af0ed97ea37210dc26fb0032647f8"
+dependencies = [
+ "windows-targets 0.52.5",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index efcf274e511..a353c79f12d 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -453,11 +453,6 @@ impl<'a> AstValidator<'a> {
                             item_span: span,
                             block: Some(self.current_extern_span().shrink_to_lo()),
                         });
-                    } else if !self.features.unsafe_extern_blocks {
-                        self.dcx().emit_err(errors::InvalidSafetyOnExtern {
-                            item_span: span,
-                            block: None,
-                        });
                     }
                 }
             }
@@ -1054,32 +1049,19 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         errors::VisibilityNotPermittedNote::IndividualForeignItems,
                     );
 
-                    if this.features.unsafe_extern_blocks {
-                        if &Safety::Default == safety {
-                            if item.span.at_least_rust_2024() {
-                                this.dcx()
-                                    .emit_err(errors::MissingUnsafeOnExtern { span: item.span });
-                            } else {
-                                this.lint_buffer.buffer_lint(
-                                    MISSING_UNSAFE_ON_EXTERN,
-                                    item.id,
-                                    item.span,
-                                    BuiltinLintDiag::MissingUnsafeOnExtern {
-                                        suggestion: item.span.shrink_to_lo(),
-                                    },
-                                );
-                            }
+                    if &Safety::Default == safety {
+                        if item.span.at_least_rust_2024() {
+                            this.dcx().emit_err(errors::MissingUnsafeOnExtern { span: item.span });
+                        } else {
+                            this.lint_buffer.buffer_lint(
+                                MISSING_UNSAFE_ON_EXTERN,
+                                item.id,
+                                item.span,
+                                BuiltinLintDiag::MissingUnsafeOnExtern {
+                                    suggestion: item.span.shrink_to_lo(),
+                                },
+                            );
                         }
-                    } else if let &Safety::Unsafe(span) = safety {
-                        let mut diag = this
-                            .dcx()
-                            .create_err(errors::UnsafeItem { span, kind: "extern block" });
-                        rustc_session::parse::add_feature_diagnostics(
-                            &mut diag,
-                            self.session,
-                            sym::unsafe_extern_blocks,
-                        );
-                        diag.emit();
                     }
 
                     if abi.is_none() {
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index e99123b9b1c..3ceb8e0711a 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -560,10 +560,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(precise_capturing, "precise captures on `impl Trait` are experimental");
     gate_all!(global_registration, "global registration is experimental");
     gate_all!(unsafe_attributes, "`#[unsafe()]` markers for attributes are experimental");
-    gate_all!(
-        unsafe_extern_blocks,
-        "`unsafe extern {}` blocks and `safe` keyword are experimental"
-    );
     gate_all!(return_type_notation, "return type notation is experimental");
 
     if !visitor.features.never_patterns {
diff --git a/compiler/rustc_builtin_macros/src/alloc_error_handler.rs b/compiler/rustc_builtin_macros/src/alloc_error_handler.rs
index 09d892768b4..1df2812e0c8 100644
--- a/compiler/rustc_builtin_macros/src/alloc_error_handler.rs
+++ b/compiler/rustc_builtin_macros/src/alloc_error_handler.rs
@@ -80,7 +80,7 @@ fn generate_handler(cx: &ExtCtxt<'_>, handler: Ident, span: Span, sig_span: Span
     let params = thin_vec![cx.param(span, size, ty_usize.clone()), cx.param(span, align, ty_usize)];
     let decl = cx.fn_decl(params, never);
     let header = FnHeader { safety: Safety::Unsafe(span), ..FnHeader::default() };
-    let sig = FnSig { decl, header, span: span };
+    let sig = FnSig { decl, header, span };
 
     let body = Some(cx.block_expr(call));
     let kind = ItemKind::Fn(Box::new(Fn {
diff --git a/compiler/rustc_builtin_macros/src/cfg_eval.rs b/compiler/rustc_builtin_macros/src/cfg_eval.rs
index dc1874bfecb..4b05c144d37 100644
--- a/compiler/rustc_builtin_macros/src/cfg_eval.rs
+++ b/compiler/rustc_builtin_macros/src/cfg_eval.rs
@@ -202,7 +202,7 @@ impl CfgEval<'_> {
         }
 
         // Now that we have our re-parsed `AttrTokenStream`, recursively configuring
-        // our attribute target will correctly the tokens as well.
+        // our attribute target will correctly configure the tokens as well.
         flat_map_annotatable(self, annotatable)
     }
 }
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 7d457526380..653895380be 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -2065,17 +2065,61 @@ fn add_local_crate_metadata_objects(
 }
 
 /// Add sysroot and other globally set directories to the directory search list.
-fn add_library_search_dirs(cmd: &mut dyn Linker, sess: &Session, self_contained: bool) {
-    // The default library location, we need this to find the runtime.
-    // The location of crates will be determined as needed.
-    let lib_path = sess.target_filesearch(PathKind::All).get_lib_path();
-    cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
+fn add_library_search_dirs(
+    cmd: &mut dyn Linker,
+    sess: &Session,
+    self_contained_components: LinkSelfContainedComponents,
+    apple_sdk_root: Option<&Path>,
+) {
+    if !sess.opts.unstable_opts.link_native_libraries {
+        return;
+    }
 
-    // Special directory with libraries used only in self-contained linkage mode
-    if self_contained {
-        let lib_path = sess.target_filesearch(PathKind::All).get_self_contained_lib_path();
+    // Library search paths explicitly supplied by user (`-L` on the command line).
+    for search_path in sess.target_filesearch(PathKind::Native).cli_search_paths() {
+        cmd.include_path(&fix_windows_verbatim_for_gcc(&search_path.dir));
+    }
+    for search_path in sess.target_filesearch(PathKind::Framework).cli_search_paths() {
+        // Contrary to the `-L` docs only framework-specific paths are considered here.
+        if search_path.kind != PathKind::All {
+            cmd.framework_path(&search_path.dir);
+        }
+    }
+
+    // The toolchain ships some native library components and self-contained linking was enabled.
+    // Add the self-contained library directory to search paths.
+    if self_contained_components.intersects(
+        LinkSelfContainedComponents::LIBC
+            | LinkSelfContainedComponents::UNWIND
+            | LinkSelfContainedComponents::MINGW,
+    ) {
+        let lib_path = sess.target_filesearch(PathKind::Native).get_self_contained_lib_path();
         cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
     }
+
+    // Toolchains for some targets may ship `libunwind.a`, but place it into the main sysroot
+    // library directory instead of the self-contained directories.
+    // Sanitizer libraries have the same issue and are also linked by name on Apple targets.
+    // The targets here should be in sync with `copy_third_party_objects` in bootstrap.
+    // FIXME: implement `-Clink-self-contained=+/-unwind,+/-sanitizers`, move the shipped libunwind
+    // and sanitizers to self-contained directory, and stop adding this search path.
+    if sess.target.vendor == "fortanix"
+        || sess.target.os == "linux"
+        || sess.target.os == "fuchsia"
+        || sess.target.is_like_osx && !sess.opts.unstable_opts.sanitizer.is_empty()
+    {
+        let lib_path = sess.target_filesearch(PathKind::Native).get_lib_path();
+        cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
+    }
+
+    // Mac Catalyst uses the macOS SDK, but to link to iOS-specific frameworks
+    // we must have the support library stubs in the library search path (#121430).
+    if let Some(sdk_root) = apple_sdk_root
+        && sess.target.llvm_target.contains("macabi")
+    {
+        cmd.include_path(&sdk_root.join("System/iOSSupport/usr/lib"));
+        cmd.framework_path(&sdk_root.join("System/iOSSupport/System/Library/Frameworks"));
+    }
 }
 
 /// Add options making relocation sections in the produced ELF files read-only
@@ -2367,7 +2411,7 @@ fn add_order_independent_options(
     // Take care of the flavors and CLI options requesting the `lld` linker.
     add_lld_args(cmd, sess, flavor, self_contained_components);
 
-    add_apple_sdk(cmd, sess, flavor);
+    let apple_sdk_root = add_apple_sdk(cmd, sess, flavor);
 
     add_link_script(cmd, sess, tmpdir, crate_type);
 
@@ -2423,7 +2467,7 @@ fn add_order_independent_options(
 
     cmd.linker_plugin_lto();
 
-    add_library_search_dirs(cmd, sess, self_contained_components.are_any_components_enabled());
+    add_library_search_dirs(cmd, sess, self_contained_components, apple_sdk_root.as_deref());
 
     cmd.output_filename(out_filename);
 
@@ -2637,19 +2681,6 @@ fn add_local_native_libraries(
     tmpdir: &Path,
     link_output_kind: LinkOutputKind,
 ) {
-    if sess.opts.unstable_opts.link_native_libraries {
-        // User-supplied library search paths (-L on the command line). These are the same paths
-        // used to find Rust crates, so some of them may have been added already by the previous
-        // crate linking code. This only allows them to be found at compile time so it is still
-        // entirely up to outside forces to make sure that library can be found at runtime.
-        for search_path in sess.target_filesearch(PathKind::All).search_paths() {
-            match search_path.kind {
-                PathKind::Framework => cmd.framework_path(&search_path.dir),
-                _ => cmd.include_path(&fix_windows_verbatim_for_gcc(&search_path.dir)),
-            }
-        }
-    }
-
     // All static and dynamic native library dependencies are linked to the local crate.
     let link_static = true;
     let link_dynamic = true;
@@ -2944,7 +2975,7 @@ pub(crate) fn are_upstream_rust_objects_already_included(sess: &Session) -> bool
     }
 }
 
-fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
+fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) -> Option<PathBuf> {
     let arch = &sess.target.arch;
     let os = &sess.target.os;
     let llvm_target = &sess.target.llvm_target;
@@ -2952,11 +2983,11 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         || !matches!(os.as_ref(), "ios" | "tvos" | "watchos" | "visionos" | "macos")
         || !matches!(flavor, LinkerFlavor::Darwin(..))
     {
-        return;
+        return None;
     }
 
     if os == "macos" && !matches!(flavor, LinkerFlavor::Darwin(Cc::No, _)) {
-        return;
+        return None;
     }
 
     let sdk_name = match (arch.as_ref(), os.as_ref()) {
@@ -2980,14 +3011,14 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         (_, "macos") => "macosx",
         _ => {
             sess.dcx().emit_err(errors::UnsupportedArch { arch, os });
-            return;
+            return None;
         }
     };
     let sdk_root = match get_apple_sdk_root(sdk_name) {
         Ok(s) => s,
         Err(e) => {
             sess.dcx().emit_err(e);
-            return;
+            return None;
         }
     };
 
@@ -3007,16 +3038,7 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         _ => unreachable!(),
     }
 
-    if llvm_target.contains("macabi") {
-        // Mac Catalyst uses the macOS SDK, but to link to iOS-specific
-        // frameworks, we must have the support library stubs in the library
-        // search path.
-
-        // The flags are called `-L` and `-F` both in Clang, ld64 and ldd.
-        let sdk_root = Path::new(&sdk_root);
-        cmd.include_path(&sdk_root.join("System/iOSSupport/usr/lib"));
-        cmd.framework_path(&sdk_root.join("System/iOSSupport/System/Library/Frameworks"));
-    }
+    Some(sdk_root.into())
 }
 
 fn get_apple_sdk_root(sdk_name: &str) -> Result<String, errors::AppleSdkRootError<'_>> {
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index 77da4e4caea..b52e6259944 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -78,6 +78,7 @@ pub fn from_target_feature(
                 Some(sym::loongarch_target_feature) => rust_features.loongarch_target_feature,
                 Some(sym::lahfsahf_target_feature) => rust_features.lahfsahf_target_feature,
                 Some(sym::prfchw_target_feature) => rust_features.prfchw_target_feature,
+                Some(sym::sha512_sm_x86) => rust_features.sha512_sm_x86,
                 Some(sym::x86_amx_intrinsics) => rust_features.x86_amx_intrinsics,
                 Some(sym::xop_target_feature) => rust_features.xop_target_feature,
                 Some(sym::s390x_target_feature) => rust_features.s390x_target_feature,
diff --git a/compiler/rustc_const_eval/messages.ftl b/compiler/rustc_const_eval/messages.ftl
index 94cdd021d8d..c64c73b2323 100644
--- a/compiler/rustc_const_eval/messages.ftl
+++ b/compiler/rustc_const_eval/messages.ftl
@@ -316,9 +316,6 @@ const_eval_range_upper = less or equal to {$hi}
 const_eval_range_wrapping = less or equal to {$hi}, or greater or equal to {$lo}
 const_eval_raw_bytes = the raw bytes of the constant (size: {$size}, align: {$align}) {"{"}{$bytes}{"}"}
 
-const_eval_raw_eq_with_provenance =
-    `raw_eq` on bytes with provenance
-
 const_eval_raw_ptr_comparison =
     pointers cannot be reliably compared during const eval
     .note = see issue #53020 <https://github.com/rust-lang/rust/issues/53020> for more information
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index fc063b8bab0..18d585e4a7a 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -877,7 +877,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         body: &'tcx mir::Body<'tcx>,
     ) -> InterpResult<'tcx> {
         // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
-        for &const_ in &body.required_consts {
+        for &const_ in body.required_consts() {
             let c =
                 self.instantiate_from_current_frame_and_normalize_erasing_regions(const_.const_)?;
             c.eval(*self.tcx, self.param_env, const_.span).map_err(|err| {
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 3cf3bd87d3d..16a0a76a316 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -690,9 +690,6 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 // zero-sized access
                 return Ok(&[]);
             };
-            if alloc_ref.has_provenance() {
-                throw_ub_custom!(fluent::const_eval_raw_eq_with_provenance);
-            }
             alloc_ref.get_bytes_strip_provenance()
         };
 
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 73908e58085..8963b009c31 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -1767,7 +1767,10 @@ impl HumanEmitter {
         debug!(?suggestions);
 
         if suggestions.is_empty() {
-            // Suggestions coming from macros can have malformed spans. This is a heavy handed
+            // Here we check if there are suggestions that have actual code changes. We sometimes
+            // suggest the same code that is already there, instead of changing how we produce the
+            // suggestions and filtering there, we just don't emit the suggestion.
+            // Suggestions coming from macros can also have malformed spans. This is a heavy handed
             // approach to avoid ICEs by ignoring the suggestion outright.
             return Ok(());
         }
@@ -2046,7 +2049,9 @@ impl HumanEmitter {
                     assert!(underline_start >= 0 && underline_end >= 0);
                     let padding: usize = max_line_num_len + 3;
                     for p in underline_start..underline_end {
-                        if let DisplaySuggestion::Underline = show_code_change {
+                        if let DisplaySuggestion::Underline = show_code_change
+                            && is_different(sm, &part.snippet, part.span)
+                        {
                             // If this is a replacement, underline with `~`, if this is an addition
                             // underline with `+`.
                             buffer.putc(
@@ -2824,6 +2829,18 @@ impl Style {
     }
 }
 
+/// Whether the original and suggested code are the same.
+pub fn is_different(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
+    let found = match sm.span_to_snippet(sp) {
+        Ok(snippet) => snippet,
+        Err(e) => {
+            warn!(error = ?e, "Invalid span {:?}", sp);
+            return true;
+        }
+    };
+    found != suggested
+}
+
 /// Whether the original and suggested code are visually similar enough to warrant extra wording.
 pub fn is_case_difference(sm: &SourceMap, suggested: &str, sp: Span) -> bool {
     // FIXME: this should probably be extended to also account for `FO0` → `FOO` and unicode.
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 09855394cdb..ceebcd46a6f 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -50,7 +50,7 @@ pub use diagnostic_impls::{
     IndicateAnonymousLifetime, SingleLabelManySpans,
 };
 pub use emitter::ColorConfig;
-use emitter::{is_case_difference, DynEmitter, Emitter};
+use emitter::{is_case_difference, is_different, DynEmitter, Emitter};
 use registry::Registry;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::stable_hasher::{Hash128, StableHasher};
@@ -357,10 +357,16 @@ impl CodeSuggestion {
                             _ => 1,
                         })
                         .sum();
-                    line_highlight.push(SubstitutionHighlight {
-                        start: (cur_lo.col.0 as isize + acc) as usize,
-                        end: (cur_lo.col.0 as isize + acc + len) as usize,
-                    });
+                    if !is_different(sm, &part.snippet, part.span) {
+                        // Account for cases where we are suggesting the same code that's already
+                        // there. This shouldn't happen often, but in some cases for multipart
+                        // suggestions it's much easier to handle it here than in the origin.
+                    } else {
+                        line_highlight.push(SubstitutionHighlight {
+                            start: (cur_lo.col.0 as isize + acc) as usize,
+                            end: (cur_lo.col.0 as isize + acc + len) as usize,
+                        });
+                    }
                     buf.push_str(&part.snippet);
                     let cur_hi = sm.lookup_char_pos(part.span.hi());
                     // Account for the difference between the width of the current code and the
@@ -392,7 +398,11 @@ impl CodeSuggestion {
                 while buf.ends_with('\n') {
                     buf.pop();
                 }
-                Some((buf, substitution.parts, highlights, only_capitalization))
+                if highlights.iter().all(|parts| parts.is_empty()) {
+                    None
+                } else {
+                    Some((buf, substitution.parts, highlights, only_capitalization))
+                }
             })
             .collect()
     }
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index 9684fe10510..e42a655531b 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -390,6 +390,8 @@ declare_features! (
     (accepted, unrestricted_attribute_tokens, "1.34.0", Some(55208)),
     /// The `unsafe_op_in_unsafe_fn` lint (allowed by default): no longer treat an unsafe function as an unsafe block.
     (accepted, unsafe_block_in_unsafe_fn, "1.52.0", Some(71668)),
+    /// Allows unsafe on extern declarations and safety qualifiers over internal items.
+    (accepted, unsafe_extern_blocks, "CURRENT_RUSTC_VERSION", Some(123743)),
     /// Allows importing and reexporting macros with `use`,
     /// enables macro modularization in general.
     (accepted, use_extern_macros, "1.30.0", Some(35896)),
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index ef03a25bc16..72ea55d5999 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -703,21 +703,21 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         EncodeCrossCrate::No, allocator_internals, experimental!(needs_allocator),
     ),
     gated!(
-        panic_runtime, Normal, template!(Word), WarnFollowing,
+        panic_runtime, CrateLevel, template!(Word), WarnFollowing,
         EncodeCrossCrate::No, experimental!(panic_runtime)
     ),
     gated!(
-        needs_panic_runtime, Normal, template!(Word), WarnFollowing,
+        needs_panic_runtime, CrateLevel, template!(Word), WarnFollowing,
         EncodeCrossCrate::No, experimental!(needs_panic_runtime)
     ),
     gated!(
-        compiler_builtins, Normal, template!(Word), WarnFollowing,
+        compiler_builtins, CrateLevel, template!(Word), WarnFollowing,
         EncodeCrossCrate::No,
         "the `#[compiler_builtins]` attribute is used to identify the `compiler_builtins` crate \
         which contains compiler-rt intrinsics and will never be stable",
     ),
     gated!(
-        profiler_runtime, Normal, template!(Word), WarnFollowing,
+        profiler_runtime, CrateLevel, template!(Word), WarnFollowing,
         EncodeCrossCrate::No,
         "the `#[profiler_runtime]` attribute is used to identify the `profiler_builtins` crate \
         which contains the profiler runtime and will never be stable",
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 03210085a12..652efa193ea 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -591,6 +591,8 @@ declare_features! (
     (incomplete, return_type_notation, "1.70.0", Some(109417)),
     /// Allows `extern "rust-cold"`.
     (unstable, rust_cold_cc, "1.63.0", Some(97544)),
+    /// Allows use of x86 SHA512, SM3 and SM4 target-features and intrinsics
+    (unstable, sha512_sm_x86, "CURRENT_RUSTC_VERSION", Some(126624)),
     /// Shortern the tail expression lifetime
     (unstable, shorter_tail_lifetimes, "1.79.0", Some(123739)),
     /// Allows the use of SIMD types in functions declared in `extern` blocks.
@@ -629,8 +631,6 @@ declare_features! (
     (incomplete, unnamed_fields, "1.74.0", Some(49804)),
     /// Allows unsafe attributes.
     (unstable, unsafe_attributes, "1.80.0", Some(123757)),
-    /// Allows unsafe on extern declarations and safety qualifiers over internal items.
-    (unstable, unsafe_extern_blocks, "1.80.0", Some(123743)),
     /// Allows const generic parameters to be defined with types that
     /// are not `Sized`, e.g. `fn foo<const N: [u8]>() {`.
     (incomplete, unsized_const_params, "CURRENT_RUSTC_VERSION", Some(95174)),
diff --git a/compiler/rustc_lint/src/macro_expr_fragment_specifier_2024_migration.rs b/compiler/rustc_lint/src/macro_expr_fragment_specifier_2024_migration.rs
index c39c86f6fe8..e3b1967da09 100644
--- a/compiler/rustc_lint/src/macro_expr_fragment_specifier_2024_migration.rs
+++ b/compiler/rustc_lint/src/macro_expr_fragment_specifier_2024_migration.rs
@@ -1,5 +1,5 @@
-//! Migration code for the `expr_fragment_specifier_2024`
-//! rule.
+//! Migration code for the `expr_fragment_specifier_2024` rule.
+
 use rustc_ast::token::{Token, TokenKind};
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_session::lint::FutureIncompatibilityReason;
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 7172a47fb85..e12ffa4bd90 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -4934,7 +4934,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(unsafe_extern_blocks)]
     /// #![warn(missing_unsafe_on_extern)]
     /// #![allow(dead_code)]
     ///
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index b9c93edcd80..46c4d586f6a 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -383,15 +383,17 @@ pub struct Body<'tcx> {
 
     /// Constants that are required to evaluate successfully for this MIR to be well-formed.
     /// We hold in this field all the constants we are not able to evaluate yet.
+    /// `None` indicates that the list has not been computed yet.
     ///
     /// This is soundness-critical, we make a guarantee that all consts syntactically mentioned in a
     /// function have successfully evaluated if the function ever gets executed at runtime.
-    pub required_consts: Vec<ConstOperand<'tcx>>,
+    pub required_consts: Option<Vec<ConstOperand<'tcx>>>,
 
     /// Further items that were mentioned in this function and hence *may* become monomorphized,
     /// depending on optimizations. We use this to avoid optimization-dependent compile errors: the
     /// collector recursively traverses all "mentioned" items and evaluates all their
     /// `required_consts`.
+    /// `None` indicates that the list has not been computed yet.
     ///
     /// This is *not* soundness-critical and the contents of this list are *not* a stable guarantee.
     /// All that's relevant is that this set is optimization-level-independent, and that it includes
@@ -399,7 +401,7 @@ pub struct Body<'tcx> {
     /// set after drop elaboration, so some drop calls that can never be reached are not considered
     /// "mentioned".) See the documentation of `CollectionMode` in
     /// `compiler/rustc_monomorphize/src/collector.rs` for more context.
-    pub mentioned_items: Vec<Spanned<MentionedItem<'tcx>>>,
+    pub mentioned_items: Option<Vec<Spanned<MentionedItem<'tcx>>>>,
 
     /// Does this body use generic parameters. This is used for the `ConstEvaluatable` check.
     ///
@@ -477,8 +479,8 @@ impl<'tcx> Body<'tcx> {
             spread_arg: None,
             var_debug_info,
             span,
-            required_consts: Vec::new(),
-            mentioned_items: Vec::new(),
+            required_consts: None,
+            mentioned_items: None,
             is_polymorphic: false,
             injection_phase: None,
             tainted_by_errors,
@@ -507,8 +509,8 @@ impl<'tcx> Body<'tcx> {
             arg_count: 0,
             spread_arg: None,
             span: DUMMY_SP,
-            required_consts: Vec::new(),
-            mentioned_items: Vec::new(),
+            required_consts: None,
+            mentioned_items: None,
             var_debug_info: Vec::new(),
             is_polymorphic: false,
             injection_phase: None,
@@ -785,6 +787,40 @@ impl<'tcx> Body<'tcx> {
         // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
         caller_location.unwrap_or_else(|| from_span(source_info.span))
     }
+
+    #[track_caller]
+    pub fn set_required_consts(&mut self, required_consts: Vec<ConstOperand<'tcx>>) {
+        assert!(
+            self.required_consts.is_none(),
+            "required_consts for {:?} have already been set",
+            self.source.def_id()
+        );
+        self.required_consts = Some(required_consts);
+    }
+    #[track_caller]
+    pub fn required_consts(&self) -> &[ConstOperand<'tcx>] {
+        match &self.required_consts {
+            Some(l) => l,
+            None => panic!("required_consts for {:?} have not yet been set", self.source.def_id()),
+        }
+    }
+
+    #[track_caller]
+    pub fn set_mentioned_items(&mut self, mentioned_items: Vec<Spanned<MentionedItem<'tcx>>>) {
+        assert!(
+            self.mentioned_items.is_none(),
+            "mentioned_items for {:?} have already been set",
+            self.source.def_id()
+        );
+        self.mentioned_items = Some(mentioned_items);
+    }
+    #[track_caller]
+    pub fn mentioned_items(&self) -> &[Spanned<MentionedItem<'tcx>>] {
+        match &self.mentioned_items {
+            Some(l) => l,
+            None => panic!("mentioned_items for {:?} have not yet been set", self.source.def_id()),
+        }
+    }
 }
 
 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs
index 0031ded2440..3921176873c 100644
--- a/compiler/rustc_middle/src/mir/visit.rs
+++ b/compiler/rustc_middle/src/mir/visit.rs
@@ -1066,9 +1066,11 @@ macro_rules! super_body {
 
         $self.visit_span($(& $mutability)? $body.span);
 
-        for const_ in &$($mutability)? $body.required_consts {
-            let location = Location::START;
-            $self.visit_const_operand(const_, location);
+        if let Some(required_consts) = &$($mutability)? $body.required_consts {
+            for const_ in required_consts {
+                let location = Location::START;
+                $self.visit_const_operand(const_, location);
+            }
         }
     }
 }
diff --git a/compiler/rustc_mir_build/src/build/custom/mod.rs b/compiler/rustc_mir_build/src/build/custom/mod.rs
index 38acb6f44f9..28477e527c7 100644
--- a/compiler/rustc_mir_build/src/build/custom/mod.rs
+++ b/compiler/rustc_mir_build/src/build/custom/mod.rs
@@ -54,8 +54,8 @@ pub(super) fn build_custom_mir<'tcx>(
         spread_arg: None,
         var_debug_info: Vec::new(),
         span,
-        required_consts: Vec::new(),
-        mentioned_items: Vec::new(),
+        required_consts: None,
+        mentioned_items: None,
         is_polymorphic: false,
         tainted_by_errors: None,
         injection_phase: None,
diff --git a/compiler/rustc_mir_transform/Cargo.toml b/compiler/rustc_mir_transform/Cargo.toml
index f864a13a31b..07ca51a67ae 100644
--- a/compiler/rustc_mir_transform/Cargo.toml
+++ b/compiler/rustc_mir_transform/Cargo.toml
@@ -25,6 +25,7 @@ rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
 rustc_trait_selection = { path = "../rustc_trait_selection" }
+rustc_type_ir = { path = "../rustc_type_ir" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 # tidy-alphabetical-end
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 36b2b3b7c44..f30732e6aaf 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -744,8 +744,8 @@ impl<'tcx> Inliner<'tcx> {
         // Copy required constants from the callee_body into the caller_body. Although we are only
         // pushing unevaluated consts to `required_consts`, here they may have been evaluated
         // because we are calling `instantiate_and_normalize_erasing_regions` -- so we filter again.
-        caller_body.required_consts.extend(
-            callee_body.required_consts.into_iter().filter(|ct| ct.const_.is_required_const()),
+        caller_body.required_consts.as_mut().unwrap().extend(
+            callee_body.required_consts().into_iter().filter(|ct| ct.const_.is_required_const()),
         );
         // Now that we incorporated the callee's `required_consts`, we can remove the callee from
         // `mentioned_items` -- but we have to take their `mentioned_items` in return. This does
@@ -755,12 +755,11 @@ impl<'tcx> Inliner<'tcx> {
         // We need to reconstruct the `required_item` for the callee so that we can find and
         // remove it.
         let callee_item = MentionedItem::Fn(func.ty(caller_body, self.tcx));
-        if let Some(idx) =
-            caller_body.mentioned_items.iter().position(|item| item.node == callee_item)
-        {
+        let caller_mentioned_items = caller_body.mentioned_items.as_mut().unwrap();
+        if let Some(idx) = caller_mentioned_items.iter().position(|item| item.node == callee_item) {
             // We found the callee, so remove it and add its items instead.
-            caller_body.mentioned_items.remove(idx);
-            caller_body.mentioned_items.extend(callee_body.mentioned_items);
+            caller_mentioned_items.remove(idx);
+            caller_mentioned_items.extend(callee_body.mentioned_items());
         } else {
             // If we can't find the callee, there's no point in adding its items. Probably it
             // already got removed by being inlined elsewhere in the same function, so we already
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index ac3a44c803a..1f214bc42cb 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -28,11 +28,10 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_index::IndexVec;
-use rustc_middle::mir::visit::Visitor as _;
 use rustc_middle::mir::{
-    traversal, AnalysisPhase, Body, CallSource, ClearCrossCrate, ConstOperand, ConstQualifs,
-    LocalDecl, MirPass, MirPhase, Operand, Place, ProjectionElem, Promoted, RuntimePhase, Rvalue,
-    SourceInfo, Statement, StatementKind, TerminatorKind, START_BLOCK,
+    AnalysisPhase, Body, CallSource, ClearCrossCrate, ConstOperand, ConstQualifs, LocalDecl,
+    MirPass, MirPhase, Operand, Place, ProjectionElem, Promoted, RuntimePhase, Rvalue, SourceInfo,
+    Statement, StatementKind, TerminatorKind, START_BLOCK,
 };
 use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_middle::util::Providers;
@@ -339,12 +338,15 @@ fn mir_promoted(
 
     // Collect `required_consts` *before* promotion, so if there are any consts being promoted
     // we still add them to the list in the outer MIR body.
-    let mut required_consts = Vec::new();
-    let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
-    for (bb, bb_data) in traversal::reverse_postorder(&body) {
-        required_consts_visitor.visit_basic_block_data(bb, bb_data);
+    RequiredConstsVisitor::compute_required_consts(&mut body);
+    // If this has an associated by-move async closure body, that doesn't get run through these
+    // passes itself, it gets "tagged along" by the pass manager. `RequiredConstsVisitor` is not
+    // a regular pass so we have to also apply it manually to the other body.
+    if let Some(coroutine) = body.coroutine.as_mut() {
+        if let Some(by_move_body) = coroutine.by_move_body.as_mut() {
+            RequiredConstsVisitor::compute_required_consts(by_move_body);
+        }
     }
-    body.required_consts = required_consts;
 
     // What we need to run borrowck etc.
     let promote_pass = promote_consts::PromoteTemps::default();
@@ -561,9 +563,6 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         tcx,
         body,
         &[
-            // Before doing anything, remember which items are being mentioned so that the set of items
-            // visited does not depend on the optimization level.
-            &mentioned_items::MentionedItems,
             // Add some UB checks before any UB gets optimized away.
             &check_alignment::CheckAlignment,
             // Before inlining: trim down MIR with passes to reduce inlining work.
@@ -657,6 +656,19 @@ fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
         return body;
     }
 
+    // Before doing anything, remember which items are being mentioned so that the set of items
+    // visited does not depend on the optimization level.
+    // We do not use `run_passes` for this as that might skip the pass if `injection_phase` is set.
+    mentioned_items::MentionedItems.run_pass(tcx, &mut body);
+    // If this has an associated by-move async closure body, that doesn't get run through these
+    // passes itself, it gets "tagged along" by the pass manager. Since we're not using the pass
+    // manager we have to do this by hand.
+    if let Some(coroutine) = body.coroutine.as_mut() {
+        if let Some(by_move_body) = coroutine.by_move_body.as_mut() {
+            mentioned_items::MentionedItems.run_pass(tcx, by_move_body);
+        }
+    }
+
     // If `mir_drops_elaborated_and_const_checked` found that the current body has unsatisfiable
     // predicates, it will shrink the MIR to a single `unreachable` terminator.
     // More generally, if MIR is a lone `unreachable`, there is nothing to optimize.
diff --git a/compiler/rustc_mir_transform/src/match_branches.rs b/compiler/rustc_mir_transform/src/match_branches.rs
index df4f3ccb9b5..47758b56f8c 100644
--- a/compiler/rustc_mir_transform/src/match_branches.rs
+++ b/compiler/rustc_mir_transform/src/match_branches.rs
@@ -3,8 +3,10 @@ use std::iter;
 use rustc_index::IndexSlice;
 use rustc_middle::mir::patch::MirPatch;
 use rustc_middle::mir::*;
+use rustc_middle::ty::layout::{IntegerExt, TyAndLayout};
 use rustc_middle::ty::{ParamEnv, ScalarInt, Ty, TyCtxt};
-use rustc_target::abi::Size;
+use rustc_target::abi::Integer;
+use rustc_type_ir::TyKind::*;
 
 use super::simplify::simplify_cfg;
 
@@ -42,10 +44,7 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
                 should_cleanup = true;
                 continue;
             }
-            // unsound: https://github.com/rust-lang/rust/issues/124150
-            if tcx.sess.opts.unstable_opts.unsound_mir_opts
-                && SimplifyToExp::default().simplify(tcx, body, bb_idx, param_env).is_some()
-            {
+            if SimplifyToExp::default().simplify(tcx, body, bb_idx, param_env).is_some() {
                 should_cleanup = true;
                 continue;
             }
@@ -264,33 +263,56 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToIf {
     }
 }
 
+/// Check if the cast constant using `IntToInt` is equal to the target constant.
+fn can_cast(
+    tcx: TyCtxt<'_>,
+    src_val: impl Into<u128>,
+    src_layout: TyAndLayout<'_>,
+    cast_ty: Ty<'_>,
+    target_scalar: ScalarInt,
+) -> bool {
+    let from_scalar = ScalarInt::try_from_uint(src_val.into(), src_layout.size).unwrap();
+    let v = match src_layout.ty.kind() {
+        Uint(_) => from_scalar.to_uint(src_layout.size),
+        Int(_) => from_scalar.to_int(src_layout.size) as u128,
+        _ => unreachable!("invalid int"),
+    };
+    let size = match *cast_ty.kind() {
+        Int(t) => Integer::from_int_ty(&tcx, t).size(),
+        Uint(t) => Integer::from_uint_ty(&tcx, t).size(),
+        _ => unreachable!("invalid int"),
+    };
+    let v = size.truncate(v);
+    let cast_scalar = ScalarInt::try_from_uint(v, size).unwrap();
+    cast_scalar == target_scalar
+}
+
 #[derive(Default)]
 struct SimplifyToExp {
-    transfrom_types: Vec<TransfromType>,
+    transfrom_kinds: Vec<TransfromKind>,
 }
 
 #[derive(Clone, Copy)]
-enum CompareType<'tcx, 'a> {
+enum ExpectedTransformKind<'tcx, 'a> {
     /// Identical statements.
     Same(&'a StatementKind<'tcx>),
     /// Assignment statements have the same value.
-    Eq(&'a Place<'tcx>, Ty<'tcx>, ScalarInt),
+    SameByEq { place: &'a Place<'tcx>, ty: Ty<'tcx>, scalar: ScalarInt },
     /// Enum variant comparison type.
-    Discr { place: &'a Place<'tcx>, ty: Ty<'tcx>, is_signed: bool },
+    Cast { place: &'a Place<'tcx>, ty: Ty<'tcx> },
 }
 
-enum TransfromType {
+enum TransfromKind {
     Same,
-    Eq,
-    Discr,
+    Cast,
 }
 
-impl From<CompareType<'_, '_>> for TransfromType {
-    fn from(compare_type: CompareType<'_, '_>) -> Self {
+impl From<ExpectedTransformKind<'_, '_>> for TransfromKind {
+    fn from(compare_type: ExpectedTransformKind<'_, '_>) -> Self {
         match compare_type {
-            CompareType::Same(_) => TransfromType::Same,
-            CompareType::Eq(_, _, _) => TransfromType::Eq,
-            CompareType::Discr { .. } => TransfromType::Discr,
+            ExpectedTransformKind::Same(_) => TransfromKind::Same,
+            ExpectedTransformKind::SameByEq { .. } => TransfromKind::Same,
+            ExpectedTransformKind::Cast { .. } => TransfromKind::Cast,
         }
     }
 }
@@ -354,7 +376,7 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp {
             return None;
         }
         let mut target_iter = targets.iter();
-        let (first_val, first_target) = target_iter.next().unwrap();
+        let (first_case_val, first_target) = target_iter.next().unwrap();
         let first_terminator_kind = &bbs[first_target].terminator().kind;
         // Check that destinations are identical, and if not, then don't optimize this block
         if !targets
@@ -364,24 +386,20 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp {
             return None;
         }
 
-        let discr_size = tcx.layout_of(param_env.and(discr_ty)).unwrap().size;
+        let discr_layout = tcx.layout_of(param_env.and(discr_ty)).unwrap();
         let first_stmts = &bbs[first_target].statements;
-        let (second_val, second_target) = target_iter.next().unwrap();
+        let (second_case_val, second_target) = target_iter.next().unwrap();
         let second_stmts = &bbs[second_target].statements;
         if first_stmts.len() != second_stmts.len() {
             return None;
         }
 
-        fn int_equal(l: ScalarInt, r: impl Into<u128>, size: Size) -> bool {
-            l.to_bits_unchecked() == ScalarInt::try_from_uint(r, size).unwrap().to_bits_unchecked()
-        }
-
         // We first compare the two branches, and then the other branches need to fulfill the same conditions.
-        let mut compare_types = Vec::new();
+        let mut expected_transform_kinds = Vec::new();
         for (f, s) in iter::zip(first_stmts, second_stmts) {
             let compare_type = match (&f.kind, &s.kind) {
                 // If two statements are exactly the same, we can optimize.
-                (f_s, s_s) if f_s == s_s => CompareType::Same(f_s),
+                (f_s, s_s) if f_s == s_s => ExpectedTransformKind::Same(f_s),
 
                 // If two statements are assignments with the match values to the same place, we can optimize.
                 (
@@ -395,22 +413,29 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp {
                         f_c.const_.try_eval_scalar_int(tcx, param_env),
                         s_c.const_.try_eval_scalar_int(tcx, param_env),
                     ) {
-                        (Some(f), Some(s)) if f == s => CompareType::Eq(lhs_f, f_c.const_.ty(), f),
-                        // Enum variants can also be simplified to an assignment statement if their values are equal.
-                        // We need to consider both unsigned and signed scenarios here.
+                        (Some(f), Some(s)) if f == s => ExpectedTransformKind::SameByEq {
+                            place: lhs_f,
+                            ty: f_c.const_.ty(),
+                            scalar: f,
+                        },
+                        // Enum variants can also be simplified to an assignment statement,
+                        // if we can use `IntToInt` cast to get an equal value.
                         (Some(f), Some(s))
-                            if ((f_c.const_.ty().is_signed() || discr_ty.is_signed())
-                                && int_equal(f, first_val, discr_size)
-                                && int_equal(s, second_val, discr_size))
-                                || (Some(f) == ScalarInt::try_from_uint(first_val, f.size())
-                                    && Some(s)
-                                        == ScalarInt::try_from_uint(second_val, s.size())) =>
+                            if (can_cast(
+                                tcx,
+                                first_case_val,
+                                discr_layout,
+                                f_c.const_.ty(),
+                                f,
+                            ) && can_cast(
+                                tcx,
+                                second_case_val,
+                                discr_layout,
+                                f_c.const_.ty(),
+                                s,
+                            )) =>
                         {
-                            CompareType::Discr {
-                                place: lhs_f,
-                                ty: f_c.const_.ty(),
-                                is_signed: f_c.const_.ty().is_signed() || discr_ty.is_signed(),
-                            }
+                            ExpectedTransformKind::Cast { place: lhs_f, ty: f_c.const_.ty() }
                         }
                         _ => {
                             return None;
@@ -421,47 +446,36 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp {
                 // Otherwise we cannot optimize. Try another block.
                 _ => return None,
             };
-            compare_types.push(compare_type);
+            expected_transform_kinds.push(compare_type);
         }
 
         // All remaining BBs need to fulfill the same pattern as the two BBs from the previous step.
         for (other_val, other_target) in target_iter {
             let other_stmts = &bbs[other_target].statements;
-            if compare_types.len() != other_stmts.len() {
+            if expected_transform_kinds.len() != other_stmts.len() {
                 return None;
             }
-            for (f, s) in iter::zip(&compare_types, other_stmts) {
+            for (f, s) in iter::zip(&expected_transform_kinds, other_stmts) {
                 match (*f, &s.kind) {
-                    (CompareType::Same(f_s), s_s) if f_s == s_s => {}
+                    (ExpectedTransformKind::Same(f_s), s_s) if f_s == s_s => {}
                     (
-                        CompareType::Eq(lhs_f, f_ty, val),
+                        ExpectedTransformKind::SameByEq { place: lhs_f, ty: f_ty, scalar },
                         StatementKind::Assign(box (lhs_s, Rvalue::Use(Operand::Constant(s_c)))),
                     ) if lhs_f == lhs_s
                         && s_c.const_.ty() == f_ty
-                        && s_c.const_.try_eval_scalar_int(tcx, param_env) == Some(val) => {}
+                        && s_c.const_.try_eval_scalar_int(tcx, param_env) == Some(scalar) => {}
                     (
-                        CompareType::Discr { place: lhs_f, ty: f_ty, is_signed },
+                        ExpectedTransformKind::Cast { place: lhs_f, ty: f_ty },
                         StatementKind::Assign(box (lhs_s, Rvalue::Use(Operand::Constant(s_c)))),
-                    ) if lhs_f == lhs_s && s_c.const_.ty() == f_ty => {
-                        let Some(f) = s_c.const_.try_eval_scalar_int(tcx, param_env) else {
-                            return None;
-                        };
-                        if is_signed
-                            && s_c.const_.ty().is_signed()
-                            && int_equal(f, other_val, discr_size)
-                        {
-                            continue;
-                        }
-                        if Some(f) == ScalarInt::try_from_uint(other_val, f.size()) {
-                            continue;
-                        }
-                        return None;
-                    }
+                    ) if let Some(f) = s_c.const_.try_eval_scalar_int(tcx, param_env)
+                        && lhs_f == lhs_s
+                        && s_c.const_.ty() == f_ty
+                        && can_cast(tcx, other_val, discr_layout, f_ty, f) => {}
                     _ => return None,
                 }
             }
         }
-        self.transfrom_types = compare_types.into_iter().map(|c| c.into()).collect();
+        self.transfrom_kinds = expected_transform_kinds.into_iter().map(|c| c.into()).collect();
         Some(())
     }
 
@@ -479,13 +493,13 @@ impl<'tcx> SimplifyMatch<'tcx> for SimplifyToExp {
         let (_, first) = targets.iter().next().unwrap();
         let first = &bbs[first];
 
-        for (t, s) in iter::zip(&self.transfrom_types, &first.statements) {
+        for (t, s) in iter::zip(&self.transfrom_kinds, &first.statements) {
             match (t, &s.kind) {
-                (TransfromType::Same, _) | (TransfromType::Eq, _) => {
+                (TransfromKind::Same, _) => {
                     patch.add_statement(parent_end, s.kind.clone());
                 }
                 (
-                    TransfromType::Discr,
+                    TransfromKind::Cast,
                     StatementKind::Assign(box (lhs, Rvalue::Use(Operand::Constant(f_c)))),
                 ) => {
                     let operand = Operand::Copy(Place::from(discr_local));
diff --git a/compiler/rustc_mir_transform/src/mentioned_items.rs b/compiler/rustc_mir_transform/src/mentioned_items.rs
index e33bdd99421..32c8064ebca 100644
--- a/compiler/rustc_mir_transform/src/mentioned_items.rs
+++ b/compiler/rustc_mir_transform/src/mentioned_items.rs
@@ -23,10 +23,9 @@ impl<'tcx> MirPass<'tcx> for MentionedItems {
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut mir::Body<'tcx>) {
-        debug_assert!(body.mentioned_items.is_empty());
         let mut mentioned_items = Vec::new();
         MentionedItemsVisitor { tcx, body, mentioned_items: &mut mentioned_items }.visit_body(body);
-        body.mentioned_items = mentioned_items;
+        body.set_mentioned_items(mentioned_items);
     }
 }
 
diff --git a/compiler/rustc_mir_transform/src/promote_consts.rs b/compiler/rustc_mir_transform/src/promote_consts.rs
index f8971387ea4..dc8e50ac8cd 100644
--- a/compiler/rustc_mir_transform/src/promote_consts.rs
+++ b/compiler/rustc_mir_transform/src/promote_consts.rs
@@ -702,6 +702,9 @@ struct Promoter<'a, 'tcx> {
     temps: &'a mut IndexVec<Local, TempState>,
     extra_statements: &'a mut Vec<(Location, Statement<'tcx>)>,
 
+    /// Used to assemble the required_consts list while building the promoted.
+    required_consts: Vec<ConstOperand<'tcx>>,
+
     /// If true, all nested temps are also kept in the
     /// source MIR, not moved to the promoted MIR.
     keep_original: bool,
@@ -924,11 +927,14 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
         let span = self.promoted.span;
         self.assign(RETURN_PLACE, rvalue, span);
 
-        // Now that we did promotion, we know whether we'll want to add this to `required_consts`.
+        // Now that we did promotion, we know whether we'll want to add this to `required_consts` of
+        // the surrounding MIR body.
         if self.add_to_required {
-            self.source.required_consts.push(promoted_op);
+            self.source.required_consts.as_mut().unwrap().push(promoted_op);
         }
 
+        self.promoted.set_required_consts(self.required_consts);
+
         self.promoted
     }
 }
@@ -947,7 +953,7 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> {
 
     fn visit_const_operand(&mut self, constant: &mut ConstOperand<'tcx>, _location: Location) {
         if constant.const_.is_required_const() {
-            self.promoted.required_consts.push(*constant);
+            self.required_consts.push(*constant);
         }
 
         // Skipping `super_constant` as the visitor is otherwise only looking for locals.
@@ -1011,9 +1017,9 @@ fn promote_candidates<'tcx>(
             extra_statements: &mut extra_statements,
             keep_original: false,
             add_to_required: false,
+            required_consts: Vec::new(),
         };
 
-        // `required_consts` of the promoted itself gets filled while building the MIR body.
         let mut promoted = promoter.promote_candidate(candidate, promotions.len());
         promoted.source.promoted = Some(promotions.next_index());
         promotions.push(promoted);
diff --git a/compiler/rustc_mir_transform/src/required_consts.rs b/compiler/rustc_mir_transform/src/required_consts.rs
index 00bfb5e6600..50637e2ac03 100644
--- a/compiler/rustc_mir_transform/src/required_consts.rs
+++ b/compiler/rustc_mir_transform/src/required_consts.rs
@@ -1,14 +1,23 @@
 use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{ConstOperand, Location};
+use rustc_middle::mir::{traversal, Body, ConstOperand, Location};
 
 pub struct RequiredConstsVisitor<'a, 'tcx> {
     required_consts: &'a mut Vec<ConstOperand<'tcx>>,
 }
 
 impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
-    pub fn new(required_consts: &'a mut Vec<ConstOperand<'tcx>>) -> Self {
+    fn new(required_consts: &'a mut Vec<ConstOperand<'tcx>>) -> Self {
         RequiredConstsVisitor { required_consts }
     }
+
+    pub fn compute_required_consts(body: &mut Body<'tcx>) {
+        let mut required_consts = Vec::new();
+        let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
+        for (bb, bb_data) in traversal::reverse_postorder(&body) {
+            required_consts_visitor.visit_basic_block_data(bb, bb_data);
+        }
+        body.set_required_consts(required_consts);
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for RequiredConstsVisitor<'_, 'tcx> {
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index e2fafa3a1a3..f41f3ef656c 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -305,7 +305,7 @@ fn new_body<'tcx>(
     arg_count: usize,
     span: Span,
 ) -> Body<'tcx> {
-    Body::new(
+    let mut body = Body::new(
         source,
         basic_blocks,
         IndexVec::from_elem_n(
@@ -326,7 +326,10 @@ fn new_body<'tcx>(
         None,
         // FIXME(compiler-errors): is this correct?
         None,
-    )
+    );
+    // Shims do not directly mention any consts.
+    body.set_required_consts(Vec::new());
+    body
 }
 
 pub struct DropShimElaborator<'a, 'tcx> {
@@ -969,13 +972,16 @@ pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
     };
 
     let source = MirSource::item(ctor_id);
-    let body = new_body(
+    let mut body = new_body(
         source,
         IndexVec::from_elem_n(start_block, 1),
         local_decls,
         sig.inputs().len(),
         span,
     );
+    // A constructor doesn't mention any other items (and we don't run the usual optimization passes
+    // so this would otherwise not get filled).
+    body.set_mentioned_items(Vec::new());
 
     crate::pass_manager::dump_mir_for_phase_change(tcx, &body);
 
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 99cac67f5b1..df2abf6dc9c 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -1229,7 +1229,7 @@ fn collect_items_of_instance<'tcx>(
 
     // Always visit all `required_consts`, so that we evaluate them and abort compilation if any of
     // them errors.
-    for const_op in &body.required_consts {
+    for const_op in body.required_consts() {
         if let Some(val) = collector.eval_constant(const_op) {
             collect_const_value(tcx, val, mentioned_items);
         }
@@ -1237,7 +1237,7 @@ fn collect_items_of_instance<'tcx>(
 
     // Always gather mentioned items. We try to avoid processing items that we have already added to
     // `used_items` above.
-    for item in &body.mentioned_items {
+    for item in body.mentioned_items() {
         if !collector.used_mentioned_items.contains(&item.node) {
             let item_mono = collector.monomorphize(item.node);
             visit_mentioned_item(tcx, &item_mono, item.span, mentioned_items);
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index f34ef071e21..8fdfbcee385 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -8,7 +8,7 @@ use rustc_span::{sym, BytePos, Span};
 use thin_vec::ThinVec;
 use tracing::debug;
 
-use super::{AttrWrapper, Capturing, FnParseMode, ForceCollect, Parser, PathStyle};
+use super::{AttrWrapper, Capturing, FnParseMode, ForceCollect, Parser, ParserRange, PathStyle};
 use crate::{errors, fluent_generated as fluent, maybe_whole};
 
 // Public for rustfmt usage
@@ -313,8 +313,8 @@ impl<'a> Parser<'a> {
                 // inner attribute, for possible later processing in a `LazyAttrTokenStream`.
                 if let Capturing::Yes = self.capture_state.capturing {
                     let end_pos = self.num_bump_calls;
-                    let range = start_pos..end_pos;
-                    self.capture_state.inner_attr_ranges.insert(attr.id, range);
+                    let parser_range = ParserRange(start_pos..end_pos);
+                    self.capture_state.inner_attr_parser_ranges.insert(attr.id, parser_range);
                 }
                 attrs.push(attr);
             } else {
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index 611dbc0535c..abf61036c2d 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -10,7 +10,10 @@ use rustc_errors::PResult;
 use rustc_session::parse::ParseSess;
 use rustc_span::{sym, Span, DUMMY_SP};
 
-use super::{Capturing, FlatToken, ForceCollect, Parser, ReplaceRange, TokenCursor};
+use super::{
+    Capturing, FlatToken, ForceCollect, NodeRange, NodeReplacement, Parser, ParserRange,
+    TokenCursor,
+};
 
 /// A wrapper type to ensure that the parser handles outer attributes correctly.
 /// When we parse outer attributes, we need to ensure that we capture tokens
@@ -28,8 +31,8 @@ use super::{Capturing, FlatToken, ForceCollect, Parser, ReplaceRange, TokenCurso
 #[derive(Debug, Clone)]
 pub struct AttrWrapper {
     attrs: AttrVec,
-    // The start of the outer attributes in the token cursor.
-    // This allows us to create a `ReplaceRange` for the entire attribute
+    // The start of the outer attributes in the parser's token stream.
+    // This lets us create a `NodeReplacement` for the entire attribute
     // target, including outer attributes.
     start_pos: u32,
 }
@@ -53,10 +56,9 @@ impl AttrWrapper {
 
     /// Prepend `self.attrs` to `attrs`.
     // FIXME: require passing an NT to prevent misuse of this method
-    pub(crate) fn prepend_to_nt_inner(self, attrs: &mut AttrVec) {
-        let mut self_attrs = self.attrs;
-        mem::swap(attrs, &mut self_attrs);
-        attrs.extend(self_attrs);
+    pub(crate) fn prepend_to_nt_inner(mut self, attrs: &mut AttrVec) {
+        mem::swap(attrs, &mut self.attrs);
+        attrs.extend(self.attrs);
     }
 
     pub fn is_empty(&self) -> bool {
@@ -89,7 +91,7 @@ struct LazyAttrTokenStreamImpl {
     cursor_snapshot: TokenCursor,
     num_calls: u32,
     break_last_token: bool,
-    replace_ranges: Box<[ReplaceRange]>,
+    node_replacements: Box<[NodeReplacement]>,
 }
 
 impl ToAttrTokenStream for LazyAttrTokenStreamImpl {
@@ -104,21 +106,24 @@ impl ToAttrTokenStream for LazyAttrTokenStreamImpl {
             .chain(iter::repeat_with(|| FlatToken::Token(cursor_snapshot.next())))
             .take(self.num_calls as usize);
 
-        if self.replace_ranges.is_empty() {
+        if self.node_replacements.is_empty() {
             make_attr_token_stream(tokens, self.break_last_token)
         } else {
             let mut tokens: Vec<_> = tokens.collect();
-            let mut replace_ranges = self.replace_ranges.to_vec();
-            replace_ranges.sort_by_key(|(range, _)| range.start);
+            let mut node_replacements = self.node_replacements.to_vec();
+            node_replacements.sort_by_key(|(range, _)| range.0.start);
 
             #[cfg(debug_assertions)]
-            for [(range, tokens), (next_range, next_tokens)] in replace_ranges.array_windows() {
+            for [(node_range, tokens), (next_node_range, next_tokens)] in
+                node_replacements.array_windows()
+            {
                 assert!(
-                    range.end <= next_range.start || range.end >= next_range.end,
-                    "Replace ranges should either be disjoint or nested: ({:?}, {:?}) ({:?}, {:?})",
-                    range,
+                    node_range.0.end <= next_node_range.0.start
+                        || node_range.0.end >= next_node_range.0.end,
+                    "Node ranges should be disjoint or nested: ({:?}, {:?}) ({:?}, {:?})",
+                    node_range,
                     tokens,
-                    next_range,
+                    next_node_range,
                     next_tokens,
                 );
             }
@@ -136,20 +141,23 @@ impl ToAttrTokenStream for LazyAttrTokenStreamImpl {
             // start position, we ensure that any (outer) replace range which
             // encloses another (inner) replace range will fully overwrite the
             // inner range's replacement.
-            for (range, target) in replace_ranges.into_iter().rev() {
-                assert!(!range.is_empty(), "Cannot replace an empty range: {range:?}");
+            for (node_range, target) in node_replacements.into_iter().rev() {
+                assert!(
+                    !node_range.0.is_empty(),
+                    "Cannot replace an empty node range: {:?}",
+                    node_range.0
+                );
 
                 // Replace the tokens in range with zero or one `FlatToken::AttrsTarget`s, plus
                 // enough `FlatToken::Empty`s to fill up the rest of the range. This keeps the
                 // total length of `tokens` constant throughout the replacement process, allowing
-                // us to use all of the `ReplaceRanges` entries without adjusting indices.
+                // us to do all replacements without adjusting indices.
                 let target_len = target.is_some() as usize;
                 tokens.splice(
-                    (range.start as usize)..(range.end as usize),
-                    target
-                        .into_iter()
-                        .map(|target| FlatToken::AttrsTarget(target))
-                        .chain(iter::repeat(FlatToken::Empty).take(range.len() - target_len)),
+                    (node_range.0.start as usize)..(node_range.0.end as usize),
+                    target.into_iter().map(|target| FlatToken::AttrsTarget(target)).chain(
+                        iter::repeat(FlatToken::Empty).take(node_range.0.len() - target_len),
+                    ),
                 );
             }
             make_attr_token_stream(tokens.into_iter(), self.break_last_token)
@@ -216,7 +224,7 @@ impl<'a> Parser<'a> {
         let cursor_snapshot = self.token_cursor.clone();
         let start_pos = self.num_bump_calls;
         let has_outer_attrs = !attrs.attrs.is_empty();
-        let replace_ranges_start = self.capture_state.replace_ranges.len();
+        let parser_replacements_start = self.capture_state.parser_replacements.len();
 
         // We set and restore `Capturing::Yes` on either side of the call to
         // `f`, so we can distinguish the outermost call to
@@ -271,7 +279,7 @@ impl<'a> Parser<'a> {
             return Ok(ret);
         }
 
-        let replace_ranges_end = self.capture_state.replace_ranges.len();
+        let parser_replacements_end = self.capture_state.parser_replacements.len();
 
         assert!(
             !(self.break_last_token && capture_trailing),
@@ -288,15 +296,16 @@ impl<'a> Parser<'a> {
 
         let num_calls = end_pos - start_pos;
 
-        // Take the captured ranges for any inner attributes that we parsed in
-        // `Parser::parse_inner_attributes`, and pair them in a `ReplaceRange`
-        // with `None`, which means the relevant tokens will be removed. (More
-        // details below.)
-        let mut inner_attr_replace_ranges = Vec::new();
+        // Take the captured `ParserRange`s for any inner attributes that we parsed in
+        // `Parser::parse_inner_attributes`, and pair them in a `ParserReplacement` with `None`,
+        // which means the relevant tokens will be removed. (More details below.)
+        let mut inner_attr_parser_replacements = Vec::new();
         for attr in ret.attrs() {
             if attr.style == ast::AttrStyle::Inner {
-                if let Some(attr_range) = self.capture_state.inner_attr_ranges.remove(&attr.id) {
-                    inner_attr_replace_ranges.push((attr_range, None));
+                if let Some(inner_attr_parser_range) =
+                    self.capture_state.inner_attr_parser_ranges.remove(&attr.id)
+                {
+                    inner_attr_parser_replacements.push((inner_attr_parser_range, None));
                 } else {
                     self.dcx().span_delayed_bug(attr.span, "Missing token range for attribute");
                 }
@@ -305,37 +314,41 @@ impl<'a> Parser<'a> {
 
         // This is hot enough for `deep-vector` that checking the conditions for an empty iterator
         // is measurably faster than actually executing the iterator.
-        let replace_ranges: Box<[ReplaceRange]> =
-            if replace_ranges_start == replace_ranges_end && inner_attr_replace_ranges.is_empty() {
-                Box::new([])
-            } else {
-                // Grab any replace ranges that occur *inside* the current AST node. We will
-                // perform the actual replacement only when we convert the `LazyAttrTokenStream` to
-                // an `AttrTokenStream`.
-                self.capture_state.replace_ranges[replace_ranges_start..replace_ranges_end]
-                    .iter()
-                    .cloned()
-                    .chain(inner_attr_replace_ranges.iter().cloned())
-                    .map(|(range, data)| ((range.start - start_pos)..(range.end - start_pos), data))
-                    .collect()
-            };
+        let node_replacements: Box<[_]> = if parser_replacements_start == parser_replacements_end
+            && inner_attr_parser_replacements.is_empty()
+        {
+            Box::new([])
+        } else {
+            // Grab any replace ranges that occur *inside* the current AST node. Convert them
+            // from `ParserRange` form to `NodeRange` form. We will perform the actual
+            // replacement only when we convert the `LazyAttrTokenStream` to an
+            // `AttrTokenStream`.
+            self.capture_state.parser_replacements
+                [parser_replacements_start..parser_replacements_end]
+                .iter()
+                .cloned()
+                .chain(inner_attr_parser_replacements.iter().cloned())
+                .map(|(parser_range, data)| (NodeRange::new(parser_range, start_pos), data))
+                .collect()
+        };
 
         // What is the status here when parsing the example code at the top of this method?
         //
         // When parsing `g`:
         // - `start_pos..end_pos` is `12..33` (`fn g { ... }`, excluding the outer attr).
-        // - `inner_attr_replace_ranges` has one entry (`5..15`, when counting from `fn`), to
+        // - `inner_attr_parser_replacements` has one entry (`ParserRange(17..27)`), to
         //   delete the inner attr's tokens.
-        //   - This entry is put into the lazy tokens for `g`, i.e. deleting the inner attr from
-        //     those tokens (if they get evaluated).
+        //   - This entry is converted to `NodeRange(5..15)` (relative to the `fn`) and put into
+        //     the lazy tokens for `g`, i.e. deleting the inner attr from those tokens (if they get
+        //     evaluated).
         //   - Those lazy tokens are also put into an `AttrsTarget` that is appended to `self`'s
         //     replace ranges at the bottom of this function, for processing when parsing `m`.
-        // - `replace_ranges_start..replace_ranges_end` is empty.
+        // - `parser_replacements_start..parser_replacements_end` is empty.
         //
         // When parsing `m`:
         // - `start_pos..end_pos` is `0..34` (`mod m`, excluding the `#[cfg_eval]` attribute).
-        // - `inner_attr_replace_ranges` is empty.
-        // - `replace_range_start..replace_ranges_end` has one entry.
+        // - `inner_attr_parser_replacements` is empty.
+        // - `parser_replacements_start..parser_replacements_end` has one entry.
         //   - One `AttrsTarget` (added below when parsing `g`) to replace all of `g` (`3..33`,
         //     including its outer attribute), with:
         //     - `attrs`: includes the outer and the inner attr.
@@ -346,7 +359,7 @@ impl<'a> Parser<'a> {
             num_calls,
             cursor_snapshot,
             break_last_token: self.break_last_token,
-            replace_ranges,
+            node_replacements,
         });
 
         // If we support tokens and don't already have them, store the newly captured tokens.
@@ -367,7 +380,7 @@ impl<'a> Parser<'a> {
             // What is the status here when parsing the example code at the top of this method?
             //
             // When parsing `g`, we add one entry:
-            // - The `start_pos..end_pos` (`3..33`) entry has a new `AttrsTarget` with:
+            // - The pushed entry (`ParserRange(3..33)`) has a new `AttrsTarget` with:
             //   - `attrs`: includes the outer and the inner attr.
             //   - `tokens`: lazy tokens for `g` (with its inner attr deleted).
             //
@@ -378,12 +391,14 @@ impl<'a> Parser<'a> {
             // cfg-expand this AST node.
             let start_pos = if has_outer_attrs { attrs.start_pos } else { start_pos };
             let target = AttrsTarget { attrs: ret.attrs().iter().cloned().collect(), tokens };
-            self.capture_state.replace_ranges.push((start_pos..end_pos, Some(target)));
+            self.capture_state
+                .parser_replacements
+                .push((ParserRange(start_pos..end_pos), Some(target)));
         } else if matches!(self.capture_state.capturing, Capturing::No) {
             // Only clear the ranges once we've finished capturing entirely, i.e. we've finished
             // the outermost call to this method.
-            self.capture_state.replace_ranges.clear();
-            self.capture_state.inner_attr_ranges.clear();
+            self.capture_state.parser_replacements.clear();
+            self.capture_state.inner_attr_parser_ranges.clear();
         }
         Ok(ret)
     }
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 1b053c39e64..ccf8dcdf0b6 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -40,14 +40,6 @@ use super::{
 };
 use crate::{errors, maybe_recover_from_interpolated_ty_qpath};
 
-#[derive(Debug)]
-pub(super) enum LhsExpr {
-    // Already parsed just the outer attributes.
-    Unparsed { attrs: AttrWrapper },
-    // Already parsed the expression.
-    Parsed { expr: P<Expr>, starts_statement: bool },
-}
-
 #[derive(Debug)]
 enum DestructuredFloat {
     /// 1e2
@@ -113,30 +105,31 @@ impl<'a> Parser<'a> {
         r: Restrictions,
         attrs: AttrWrapper,
     ) -> PResult<'a, P<Expr>> {
-        self.with_res(r, |this| this.parse_expr_assoc_with(0, LhsExpr::Unparsed { attrs }))
+        self.with_res(r, |this| this.parse_expr_assoc_with(0, attrs))
     }
 
     /// Parses an associative expression with operators of at least `min_prec` precedence.
     pub(super) fn parse_expr_assoc_with(
         &mut self,
         min_prec: usize,
-        lhs: LhsExpr,
+        attrs: AttrWrapper,
     ) -> PResult<'a, P<Expr>> {
-        let mut starts_stmt = false;
-        let mut lhs = match lhs {
-            LhsExpr::Parsed { expr, starts_statement } => {
-                starts_stmt = starts_statement;
-                expr
-            }
-            LhsExpr::Unparsed { attrs } => {
-                if self.token.is_range_separator() {
-                    return self.parse_expr_prefix_range(attrs);
-                } else {
-                    self.parse_expr_prefix(attrs)?
-                }
-            }
+        let lhs = if self.token.is_range_separator() {
+            return self.parse_expr_prefix_range(attrs);
+        } else {
+            self.parse_expr_prefix(attrs)?
         };
+        self.parse_expr_assoc_rest_with(min_prec, false, lhs)
+    }
 
+    /// Parses the rest of an associative expression (i.e. the part after the lhs) with operators
+    /// of at least `min_prec` precedence.
+    pub(super) fn parse_expr_assoc_rest_with(
+        &mut self,
+        min_prec: usize,
+        starts_stmt: bool,
+        mut lhs: P<Expr>,
+    ) -> PResult<'a, P<Expr>> {
         if !self.should_continue_as_assoc_expr(&lhs) {
             return Ok(lhs);
         }
@@ -272,7 +265,7 @@ impl<'a> Parser<'a> {
             };
             let rhs = self.with_res(restrictions - Restrictions::STMT_EXPR, |this| {
                 let attrs = this.parse_outer_attributes()?;
-                this.parse_expr_assoc_with(prec + prec_adjustment, LhsExpr::Unparsed { attrs })
+                this.parse_expr_assoc_with(prec + prec_adjustment, attrs)
             })?;
 
             let span = self.mk_expr_sp(&lhs, lhs_span, rhs.span);
@@ -447,7 +440,7 @@ impl<'a> Parser<'a> {
             let maybe_lt = self.token.clone();
             let attrs = self.parse_outer_attributes()?;
             Some(
-                self.parse_expr_assoc_with(prec + 1, LhsExpr::Unparsed { attrs })
+                self.parse_expr_assoc_with(prec + 1, attrs)
                     .map_err(|err| self.maybe_err_dotdotlt_syntax(maybe_lt, err))?,
             )
         } else {
@@ -504,12 +497,9 @@ impl<'a> Parser<'a> {
             let (span, opt_end) = if this.is_at_start_of_range_notation_rhs() {
                 // RHS must be parsed with more associativity than the dots.
                 let attrs = this.parse_outer_attributes()?;
-                this.parse_expr_assoc_with(
-                    op.unwrap().precedence() + 1,
-                    LhsExpr::Unparsed { attrs },
-                )
-                .map(|x| (lo.to(x.span), Some(x)))
-                .map_err(|err| this.maybe_err_dotdotlt_syntax(maybe_lt, err))?
+                this.parse_expr_assoc_with(op.unwrap().precedence() + 1, attrs)
+                    .map(|x| (lo.to(x.span), Some(x)))
+                    .map_err(|err| this.maybe_err_dotdotlt_syntax(maybe_lt, err))?
             } else {
                 (lo, None)
             };
@@ -889,7 +879,7 @@ impl<'a> Parser<'a> {
         mut e: P<Expr>,
         lo: Span,
     ) -> PResult<'a, P<Expr>> {
-        let res = ensure_sufficient_stack(|| {
+        let mut res = ensure_sufficient_stack(|| {
             loop {
                 let has_question =
                     if self.prev_token.kind == TokenKind::Ident(kw::Return, IdentIsRaw::No) {
@@ -936,17 +926,13 @@ impl<'a> Parser<'a> {
 
         // Stitch the list of outer attributes onto the return value. A little
         // bit ugly, but the best way given the current code structure.
-        if attrs.is_empty() {
-            res
-        } else {
-            res.map(|expr| {
-                expr.map(|mut expr| {
-                    attrs.extend(expr.attrs);
-                    expr.attrs = attrs;
-                    expr
-                })
-            })
+        if !attrs.is_empty()
+            && let Ok(expr) = &mut res
+        {
+            mem::swap(&mut expr.attrs, &mut attrs);
+            expr.attrs.extend(attrs)
         }
+        res
     }
 
     pub(super) fn parse_dot_suffix_expr(
@@ -2647,10 +2633,7 @@ impl<'a> Parser<'a> {
             self.expect(&token::Eq)?;
         }
         let attrs = self.parse_outer_attributes()?;
-        let expr = self.parse_expr_assoc_with(
-            1 + prec_let_scrutinee_needs_par(),
-            LhsExpr::Unparsed { attrs },
-        )?;
+        let expr = self.parse_expr_assoc_with(1 + prec_let_scrutinee_needs_par(), attrs)?;
         let span = lo.to(expr.span);
         Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span, recovered)))
     }
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index e01f605722b..4b8e4c25e16 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -192,24 +192,54 @@ struct ClosureSpans {
     body: Span,
 }
 
-/// Indicates a range of tokens that should be replaced by
-/// the tokens in the provided `AttrsTarget`. This is used in two
-/// places during token collection:
+/// A token range within a `Parser`'s full token stream.
+#[derive(Clone, Debug)]
+struct ParserRange(Range<u32>);
+
+/// A token range within an individual AST node's (lazy) token stream, i.e.
+/// relative to that node's first token. Distinct from `ParserRange` so the two
+/// kinds of range can't be mixed up.
+#[derive(Clone, Debug)]
+struct NodeRange(Range<u32>);
+
+/// Indicates a range of tokens that should be replaced by an `AttrsTarget`
+/// (replacement) or be replaced by nothing (deletion). This is used in two
+/// places during token collection.
 ///
-/// 1. During the parsing of an AST node that may have a `#[derive]`
-/// attribute, we parse a nested AST node that has `#[cfg]` or `#[cfg_attr]`
-/// In this case, we use a `ReplaceRange` to replace the entire inner AST node
-/// with `FlatToken::AttrsTarget`, allowing us to perform eager cfg-expansion
-/// on an `AttrTokenStream`.
+/// 1. Replacement. During the parsing of an AST node that may have a
+///    `#[derive]` attribute, when we parse a nested AST node that has `#[cfg]`
+///    or `#[cfg_attr]`, we replace the entire inner AST node with
+///    `FlatToken::AttrsTarget`. This lets us perform eager cfg-expansion on an
+///    `AttrTokenStream`.
 ///
-/// 2. When we parse an inner attribute while collecting tokens. We
-/// remove inner attributes from the token stream entirely, and
-/// instead track them through the `attrs` field on the AST node.
-/// This allows us to easily manipulate them (for example, removing
-/// the first macro inner attribute to invoke a proc-macro).
-/// When create a `TokenStream`, the inner attributes get inserted
-/// into the proper place in the token stream.
-type ReplaceRange = (Range<u32>, Option<AttrsTarget>);
+/// 2. Deletion. We delete inner attributes from all collected token streams,
+///    and instead track them through the `attrs` field on the AST node. This
+///    lets us manipulate them similarly to outer attributes. When we create a
+///    `TokenStream`, the inner attributes are inserted into the proper place
+///    in the token stream.
+///
+/// Each replacement starts off in `ParserReplacement` form but is converted to
+/// `NodeReplacement` form when it is attached to a single AST node, via
+/// `LazyAttrTokenStreamImpl`.
+type ParserReplacement = (ParserRange, Option<AttrsTarget>);
+
+/// See the comment on `ParserReplacement`.
+type NodeReplacement = (NodeRange, Option<AttrsTarget>);
+
+impl NodeRange {
+    // Converts a range within a parser's tokens to a range within a
+    // node's tokens beginning at `start_pos`.
+    //
+    // For example, imagine a parser with 50 tokens in its token stream, a
+    // function that spans `ParserRange(20..40)` and an inner attribute within
+    // that function that spans `ParserRange(30..35)`. We would find the inner
+    // attribute's range within the function's tokens by subtracting 20, which
+    // is the position of the function's start token. This gives
+    // `NodeRange(10..15)`.
+    fn new(ParserRange(parser_range): ParserRange, start_pos: u32) -> NodeRange {
+        NodeRange((parser_range.start - start_pos)..(parser_range.end - start_pos))
+    }
+}
 
 /// Controls how we capture tokens. Capturing can be expensive,
 /// so we try to avoid performing capturing in cases where
@@ -226,8 +256,8 @@ enum Capturing {
 #[derive(Clone, Debug)]
 struct CaptureState {
     capturing: Capturing,
-    replace_ranges: Vec<ReplaceRange>,
-    inner_attr_ranges: FxHashMap<AttrId, Range<u32>>,
+    parser_replacements: Vec<ParserReplacement>,
+    inner_attr_parser_ranges: FxHashMap<AttrId, ParserRange>,
 }
 
 /// Iterator over a `TokenStream` that produces `Token`s. It's a bit odd that
@@ -417,8 +447,8 @@ impl<'a> Parser<'a> {
             subparser_name,
             capture_state: CaptureState {
                 capturing: Capturing::No,
-                replace_ranges: Vec::new(),
-                inner_attr_ranges: Default::default(),
+                parser_replacements: Vec::new(),
+                inner_attr_parser_ranges: Default::default(),
             },
             current_closure: None,
             recovery: Recovery::Allowed,
@@ -1220,9 +1250,6 @@ impl<'a> Parser<'a> {
         if self.eat_keyword_case(kw::Unsafe, case) {
             Safety::Unsafe(self.prev_token.uninterpolated_span())
         } else if self.eat_keyword_case(kw::Safe, case) {
-            self.psess
-                .gated_spans
-                .gate(sym::unsafe_extern_blocks, self.prev_token.uninterpolated_span());
             Safety::Safe(self.prev_token.uninterpolated_span())
         } else {
             Safety::Default
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index b6f85cc9032..5bfb8bdf776 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -25,7 +25,7 @@ use crate::errors::{
     UnexpectedParenInRangePat, UnexpectedParenInRangePatSugg,
     UnexpectedVertVertBeforeFunctionParam, UnexpectedVertVertInPattern, WrapInParens,
 };
-use crate::parser::expr::{could_be_unclosed_char_literal, LhsExpr};
+use crate::parser::expr::could_be_unclosed_char_literal;
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 
 #[derive(PartialEq, Copy, Clone)]
@@ -403,8 +403,9 @@ impl<'a> Parser<'a> {
 
             // Parse an associative expression such as `+ expr`, `% expr`, ...
             // Assignements, ranges and `|` are disabled by [`Restrictions::IS_PAT`].
-            let lhs = LhsExpr::Parsed { expr, starts_statement: false };
-            if let Ok(expr) = snapshot.parse_expr_assoc_with(0, lhs).map_err(|err| err.cancel()) {
+            if let Ok(expr) =
+                snapshot.parse_expr_assoc_rest_with(0, false, expr).map_err(|err| err.cancel())
+            {
                 // We got a valid expression.
                 self.restore_snapshot(snapshot);
                 self.restrictions.remove(Restrictions::IS_PAT);
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 7b0daaa1433..b3efb87a4a2 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -17,7 +17,6 @@ use thin_vec::{thin_vec, ThinVec};
 
 use super::attr::InnerAttrForbiddenReason;
 use super::diagnostics::AttemptLocalParseRecovery;
-use super::expr::LhsExpr;
 use super::pat::{PatternLocation, RecoverComma};
 use super::path::PathStyle;
 use super::{
@@ -66,7 +65,12 @@ impl<'a> Parser<'a> {
         }
 
         Ok(Some(if self.token.is_keyword(kw::Let) {
-            self.parse_local_mk(lo, attrs, capture_semi, force_collect)?
+            self.collect_tokens_trailing_token(attrs, force_collect, |this, attrs| {
+                this.expect_keyword(kw::Let)?;
+                let local = this.parse_local(attrs)?;
+                let trailing = capture_semi && this.token.kind == token::Semi;
+                Ok((this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)), trailing))
+            })?
         } else if self.is_kw_followed_by_ident(kw::Mut) && self.may_recover() {
             self.recover_stmt_local_after_let(
                 lo,
@@ -112,13 +116,12 @@ impl<'a> Parser<'a> {
                 }
             }
         } else if let Some(item) = self.parse_item_common(
-            attrs.clone(),
+            attrs.clone(), // FIXME: unwanted clone of attrs
             false,
             true,
             FnParseMode { req_name: |_| true, req_body: true },
             force_collect,
         )? {
-            // FIXME: Bad copy of attrs
             self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
         } else if self.eat(&token::Semi) {
             // Do not attempt to parse an expression if we're done here.
@@ -173,7 +176,7 @@ impl<'a> Parser<'a> {
             // Perform this outside of the `collect_tokens_trailing_token` closure,
             // since our outer attributes do not apply to this part of the expression
             let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
-                this.parse_expr_assoc_with(0, LhsExpr::Parsed { expr, starts_statement: true })
+                this.parse_expr_assoc_rest_with(0, true, expr)
             })?;
             Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
         } else {
@@ -206,8 +209,7 @@ impl<'a> Parser<'a> {
             let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
             let e = self.maybe_recover_from_bad_qpath(e)?;
             let e = self.parse_expr_dot_or_call_with(attrs, e, lo)?;
-            let e = self
-                .parse_expr_assoc_with(0, LhsExpr::Parsed { expr: e, starts_statement: false })?;
+            let e = self.parse_expr_assoc_rest_with(0, false, e)?;
             StmtKind::Expr(e)
         };
         Ok(self.mk_stmt(lo.to(hi), kind))
@@ -247,21 +249,6 @@ impl<'a> Parser<'a> {
         Ok(stmt)
     }
 
-    fn parse_local_mk(
-        &mut self,
-        lo: Span,
-        attrs: AttrWrapper,
-        capture_semi: bool,
-        force_collect: ForceCollect,
-    ) -> PResult<'a, Stmt> {
-        self.collect_tokens_trailing_token(attrs, force_collect, |this, attrs| {
-            this.expect_keyword(kw::Let)?;
-            let local = this.parse_local(attrs)?;
-            let trailing = capture_semi && this.token.kind == token::Semi;
-            Ok((this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Let(local)), trailing))
-        })
-    }
-
     /// Parses a local variable declaration.
     fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
         let lo = self.prev_token.span;
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index 1747307a1b2..59c9d1e49f5 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -100,6 +100,10 @@ passes_continue_labeled_block =
     .label = labeled blocks cannot be `continue`'d
     .block_label = labeled block the `continue` points to
 
+passes_coroutine_on_non_closure =
+    attribute should be applied to closures
+    .label = not a closure
+
 passes_coverage_not_fn_or_closure =
     attribute should be applied to a function definition or closure
     .label = not a function or closure
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 86b18570f37..a0d0d80b957 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -20,13 +20,13 @@ use rustc_hir::{
     TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
 };
 use rustc_macros::LintDiagnostic;
-use rustc_middle::bug;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault;
 use rustc_middle::query::Providers;
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::{bug, span_bug};
 use rustc_session::lint::builtin::{
     CONFLICTING_REPR_HINTS, INVALID_DOC_ATTRIBUTES, INVALID_MACRO_EXPORT_ARGUMENTS,
     UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES, UNUSED_ATTRIBUTES,
@@ -116,130 +116,184 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         let attrs = self.tcx.hir().attrs(hir_id);
         for attr in attrs {
             match attr.path().as_slice() {
-                [sym::diagnostic, sym::do_not_recommend] => {
+                [sym::diagnostic, sym::do_not_recommend, ..] => {
                     self.check_do_not_recommend(attr.span, hir_id, target)
                 }
-                [sym::diagnostic, sym::on_unimplemented] => {
+                [sym::diagnostic, sym::on_unimplemented, ..] => {
                     self.check_diagnostic_on_unimplemented(attr.span, hir_id, target)
                 }
-                [sym::inline] => self.check_inline(hir_id, attr, span, target),
-                [sym::coverage] => self.check_coverage(attr, span, target),
-                [sym::optimize] => self.check_optimize(hir_id, attr, target),
-                [sym::non_exhaustive] => self.check_non_exhaustive(hir_id, attr, span, target),
-                [sym::marker] => self.check_marker(hir_id, attr, span, target),
-                [sym::target_feature] => {
+                [sym::inline, ..] => self.check_inline(hir_id, attr, span, target),
+                [sym::coverage, ..] => self.check_coverage(attr, span, target),
+                [sym::optimize, ..] => self.check_optimize(hir_id, attr, target),
+                [sym::non_exhaustive, ..] => self.check_non_exhaustive(hir_id, attr, span, target),
+                [sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
+                [sym::target_feature, ..] => {
                     self.check_target_feature(hir_id, attr, span, target, attrs)
                 }
-                [sym::thread_local] => self.check_thread_local(attr, span, target),
-                [sym::track_caller] => {
+                [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
+                [sym::track_caller, ..] => {
                     self.check_track_caller(hir_id, attr.span, attrs, span, target)
                 }
-                [sym::doc] => self.check_doc_attrs(
+                [sym::doc, ..] => self.check_doc_attrs(
                     attr,
                     hir_id,
                     target,
                     &mut specified_inline,
                     &mut doc_aliases,
                 ),
-                [sym::no_link] => self.check_no_link(hir_id, attr, span, target),
-                [sym::export_name] => self.check_export_name(hir_id, attr, span, target),
-                [sym::rustc_layout_scalar_valid_range_start]
-                | [sym::rustc_layout_scalar_valid_range_end] => {
+                [sym::no_link, ..] => self.check_no_link(hir_id, attr, span, target),
+                [sym::export_name, ..] => self.check_export_name(hir_id, attr, span, target),
+                [sym::rustc_layout_scalar_valid_range_start, ..]
+                | [sym::rustc_layout_scalar_valid_range_end, ..] => {
                     self.check_rustc_layout_scalar_valid_range(attr, span, target)
                 }
-                [sym::allow_internal_unstable] => {
+                [sym::allow_internal_unstable, ..] => {
                     self.check_allow_internal_unstable(hir_id, attr, span, target, attrs)
                 }
-                [sym::debugger_visualizer] => self.check_debugger_visualizer(attr, target),
-                [sym::rustc_allow_const_fn_unstable] => {
+                [sym::debugger_visualizer, ..] => self.check_debugger_visualizer(attr, target),
+                [sym::rustc_allow_const_fn_unstable, ..] => {
                     self.check_rustc_allow_const_fn_unstable(hir_id, attr, span, target)
                 }
-                [sym::rustc_std_internal_symbol] => {
+                [sym::rustc_std_internal_symbol, ..] => {
                     self.check_rustc_std_internal_symbol(attr, span, target)
                 }
-                [sym::naked] => self.check_naked(hir_id, attr, span, target, attrs),
-                [sym::rustc_never_returns_null_ptr] => {
+                [sym::naked, ..] => self.check_naked(hir_id, attr, span, target, attrs),
+                [sym::rustc_never_returns_null_ptr, ..] => {
                     self.check_applied_to_fn_or_method(hir_id, attr, span, target)
                 }
-                [sym::rustc_legacy_const_generics] => {
+                [sym::rustc_legacy_const_generics, ..] => {
                     self.check_rustc_legacy_const_generics(hir_id, attr, span, target, item)
                 }
-                [sym::rustc_lint_query_instability] => {
+                [sym::rustc_lint_query_instability, ..] => {
                     self.check_rustc_lint_query_instability(hir_id, attr, span, target)
                 }
-                [sym::rustc_lint_diagnostics] => {
+                [sym::rustc_lint_diagnostics, ..] => {
                     self.check_rustc_lint_diagnostics(hir_id, attr, span, target)
                 }
-                [sym::rustc_lint_opt_ty] => self.check_rustc_lint_opt_ty(attr, span, target),
-                [sym::rustc_lint_opt_deny_field_access] => {
+                [sym::rustc_lint_opt_ty, ..] => self.check_rustc_lint_opt_ty(attr, span, target),
+                [sym::rustc_lint_opt_deny_field_access, ..] => {
                     self.check_rustc_lint_opt_deny_field_access(attr, span, target)
                 }
-                [sym::rustc_clean]
-                | [sym::rustc_dirty]
-                | [sym::rustc_if_this_changed]
-                | [sym::rustc_then_this_would_need] => self.check_rustc_dirty_clean(attr),
-                [sym::rustc_coinductive]
-                | [sym::rustc_must_implement_one_of]
-                | [sym::rustc_deny_explicit_impl]
-                | [sym::const_trait] => self.check_must_be_applied_to_trait(attr, span, target),
-                [sym::cmse_nonsecure_entry] => {
+                [sym::rustc_clean, ..]
+                | [sym::rustc_dirty, ..]
+                | [sym::rustc_if_this_changed, ..]
+                | [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
+                [sym::rustc_coinductive, ..]
+                | [sym::rustc_must_implement_one_of, ..]
+                | [sym::rustc_deny_explicit_impl, ..]
+                | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr, span, target),
+                [sym::cmse_nonsecure_entry, ..] => {
                     self.check_cmse_nonsecure_entry(hir_id, attr, span, target)
                 }
-                [sym::collapse_debuginfo] => self.check_collapse_debuginfo(attr, span, target),
-                [sym::must_not_suspend] => self.check_must_not_suspend(attr, span, target),
-                [sym::must_use] => self.check_must_use(hir_id, attr, target),
-                [sym::rustc_pass_by_value] => self.check_pass_by_value(attr, span, target),
-                [sym::rustc_allow_incoherent_impl] => {
+                [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
+                [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
+                [sym::must_use, ..] => self.check_must_use(hir_id, attr, target),
+                [sym::rustc_pass_by_value, ..] => self.check_pass_by_value(attr, span, target),
+                [sym::rustc_allow_incoherent_impl, ..] => {
                     self.check_allow_incoherent_impl(attr, span, target)
                 }
-                [sym::rustc_has_incoherent_inherent_impls] => {
+                [sym::rustc_has_incoherent_inherent_impls, ..] => {
                     self.check_has_incoherent_inherent_impls(attr, span, target)
                 }
-                [sym::ffi_pure] => self.check_ffi_pure(attr.span, attrs, target),
-                [sym::ffi_const] => self.check_ffi_const(attr.span, target),
-                [sym::rustc_const_unstable]
-                | [sym::rustc_const_stable]
-                | [sym::unstable]
-                | [sym::stable]
-                | [sym::rustc_allowed_through_unstable_modules]
-                | [sym::rustc_promotable] => self.check_stability_promotable(attr, target),
-                [sym::link_ordinal] => self.check_link_ordinal(attr, span, target),
-                [sym::rustc_confusables] => self.check_confusables(attr, target),
-                [sym::rustc_safe_intrinsic] => {
+                [sym::ffi_pure, ..] => self.check_ffi_pure(attr.span, attrs, target),
+                [sym::ffi_const, ..] => self.check_ffi_const(attr.span, target),
+                [sym::rustc_const_unstable, ..]
+                | [sym::rustc_const_stable, ..]
+                | [sym::unstable, ..]
+                | [sym::stable, ..]
+                | [sym::rustc_allowed_through_unstable_modules, ..]
+                | [sym::rustc_promotable, ..] => self.check_stability_promotable(attr, target),
+                [sym::link_ordinal, ..] => self.check_link_ordinal(attr, span, target),
+                [sym::rustc_confusables, ..] => self.check_confusables(attr, target),
+                [sym::rustc_safe_intrinsic, ..] => {
                     self.check_rustc_safe_intrinsic(hir_id, attr, span, target)
                 }
-                [sym::cold] => self.check_cold(hir_id, attr, span, target),
-                [sym::link] => self.check_link(hir_id, attr, span, target),
-                [sym::link_name] => self.check_link_name(hir_id, attr, span, target),
-                [sym::link_section] => self.check_link_section(hir_id, attr, span, target),
-                [sym::no_mangle] => self.check_no_mangle(hir_id, attr, span, target),
-                [sym::deprecated] => self.check_deprecated(hir_id, attr, span, target),
-                [sym::macro_use] | [sym::macro_escape] => {
+                [sym::cold, ..] => self.check_cold(hir_id, attr, span, target),
+                [sym::link, ..] => self.check_link(hir_id, attr, span, target),
+                [sym::link_name, ..] => self.check_link_name(hir_id, attr, span, target),
+                [sym::link_section, ..] => self.check_link_section(hir_id, attr, span, target),
+                [sym::no_mangle, ..] => self.check_no_mangle(hir_id, attr, span, target),
+                [sym::deprecated, ..] => self.check_deprecated(hir_id, attr, span, target),
+                [sym::macro_use, ..] | [sym::macro_escape, ..] => {
                     self.check_macro_use(hir_id, attr, target)
                 }
-                [sym::path] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
-                [sym::macro_export] => self.check_macro_export(hir_id, attr, target),
-                [sym::ignore] | [sym::should_panic] => {
+                [sym::path, ..] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
+                [sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
+                [sym::ignore, ..] | [sym::should_panic, ..] => {
                     self.check_generic_attr(hir_id, attr, target, Target::Fn)
                 }
-                [sym::automatically_derived] => {
+                [sym::automatically_derived, ..] => {
                     self.check_generic_attr(hir_id, attr, target, Target::Impl)
                 }
-                [sym::no_implicit_prelude] => {
+                [sym::no_implicit_prelude, ..] => {
                     self.check_generic_attr(hir_id, attr, target, Target::Mod)
                 }
-                [sym::rustc_object_lifetime_default] => self.check_object_lifetime_default(hir_id),
-                [sym::proc_macro] => {
+                [sym::rustc_object_lifetime_default, ..] => self.check_object_lifetime_default(hir_id),
+                [sym::proc_macro, ..] => {
                     self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
                 }
-                [sym::proc_macro_attribute] => {
+                [sym::proc_macro_attribute, ..] => {
                     self.check_proc_macro(hir_id, target, ProcMacroKind::Attribute);
                 }
-                [sym::proc_macro_derive] => {
+                [sym::proc_macro_derive, ..] => {
                     self.check_generic_attr(hir_id, attr, target, Target::Fn);
                     self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
                 }
-                _ => {}
+                [sym::coroutine, ..] => {
+                    self.check_coroutine(attr, target);
+                }
+                [
+                    // ok
+                    sym::allow
+                    | sym::expect
+                    | sym::warn
+                    | sym::deny
+                    | sym::forbid
+                    | sym::cfg
+                    // need to be fixed
+                    | sym::cfi_encoding // FIXME(cfi_encoding)
+                    | sym::may_dangle // FIXME(dropck_eyepatch)
+                    | sym::pointee // FIXME(derive_smart_pointer)
+                    | sym::linkage // FIXME(linkage)
+                    | sym::no_sanitize // FIXME(no_sanitize)
+                    | sym::omit_gdb_pretty_printer_section // FIXME(omit_gdb_pretty_printer_section)
+                    | sym::used // handled elsewhere to restrict to static items
+                    | sym::repr // handled elsewhere to restrict to type decls items
+                    | sym::instruction_set // broken on stable!!!
+                    | sym::windows_subsystem // broken on stable!!!
+                    | sym::patchable_function_entry // FIXME(patchable_function_entry)
+                    | sym::deprecated_safe // FIXME(deprecated_safe)
+                    // internal
+                    | sym::prelude_import
+                    | sym::panic_handler
+                    | sym::allow_internal_unsafe
+                    | sym::fundamental
+                    | sym::lang
+                    | sym::needs_allocator
+                    | sym::default_lib_allocator
+                    | sym::start
+                    | sym::custom_mir,
+                    ..
+                ] => {}
+                [name, ..] => {
+                    match BUILTIN_ATTRIBUTE_MAP.get(name) {
+                        // checked below
+                        Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
+                        Some(_) => {
+                            // FIXME: differentiate between unstable and internal attributes just
+                            // like we do with features instead of just accepting `rustc_`
+                            // attributes by name. That should allow trimming the above list, too.
+                            if !name.as_str().starts_with("rustc_") {
+                                span_bug!(
+                                    attr.span,
+                                    "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
+                                )
+                            }
+                        }
+                        None => (),
+                    }
+                }
+                [] => unreachable!(),
             }
 
             let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
@@ -376,6 +430,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
 
     /// Checks that `#[optimize(..)]` is applied to a function/closure/method,
     /// or to an impl block or module.
+    // FIXME(#128488): this should probably be elevated to an error?
     fn check_optimize(&self, hir_id: HirId, attr: &Attribute, target: Target) {
         match target {
             Target::Fn
@@ -2279,6 +2334,15 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             self.abort.set(true);
         }
     }
+
+    fn check_coroutine(&self, attr: &Attribute, target: Target) {
+        match target {
+            Target::Closure => return,
+            _ => {
+                self.dcx().emit_err(errors::CoroutineOnNonClosure { span: attr.span });
+            }
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 8a931fc4158..7ae5c904004 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -17,7 +17,7 @@ use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::privacy::Level;
 use rustc_middle::query::Providers;
-use rustc_middle::ty::{self, AssocItemContainer, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
 use rustc_session::lint::builtin::DEAD_CODE;
@@ -44,81 +44,18 @@ fn should_explore(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
     )
 }
 
-struct Publicness {
-    ty_is_public: bool,
-    ty_and_all_fields_are_public: bool,
-}
-
-impl Publicness {
-    fn new(ty_is_public: bool, ty_and_all_fields_are_public: bool) -> Self {
-        Self { ty_is_public, ty_and_all_fields_are_public }
+fn ty_ref_to_pub_struct(tcx: TyCtxt<'_>, ty: &hir::Ty<'_>) -> bool {
+    if let TyKind::Path(hir::QPath::Resolved(_, path)) = ty.kind
+        && let Res::Def(def_kind, def_id) = path.res
+        && def_id.is_local()
+        && matches!(def_kind, DefKind::Struct | DefKind::Enum | DefKind::Union)
+    {
+        tcx.visibility(def_id).is_public()
+    } else {
+        true
     }
 }
 
-fn adt_of<'tcx>(ty: &hir::Ty<'tcx>) -> Option<(LocalDefId, DefKind)> {
-    match ty.kind {
-        TyKind::Path(hir::QPath::Resolved(_, path)) => {
-            if let Res::Def(def_kind, def_id) = path.res
-                && let Some(local_def_id) = def_id.as_local()
-            {
-                Some((local_def_id, def_kind))
-            } else {
-                None
-            }
-        }
-        TyKind::Slice(ty) | TyKind::Array(ty, _) => adt_of(ty),
-        TyKind::Ptr(ty) | TyKind::Ref(_, ty) => adt_of(ty.ty),
-        _ => None,
-    }
-}
-
-fn struct_all_fields_are_public(tcx: TyCtxt<'_>, id: LocalDefId) -> bool {
-    let adt_def = tcx.adt_def(id);
-
-    // skip types contain fields of unit and never type,
-    // it's usually intentional to make the type not constructible
-    let not_require_constructor = adt_def.all_fields().any(|field| {
-        let field_type = tcx.type_of(field.did).instantiate_identity();
-        field_type.is_unit() || field_type.is_never()
-    });
-
-    not_require_constructor
-        || adt_def.all_fields().all(|field| {
-            let field_type = tcx.type_of(field.did).instantiate_identity();
-            // skip fields of PhantomData,
-            // cause it's a common way to check things like well-formedness
-            if field_type.is_phantom_data() {
-                return true;
-            }
-
-            field.vis.is_public()
-        })
-}
-
-/// check struct and its fields are public or not,
-/// for enum and union, just check they are public,
-/// and doesn't solve types like &T for now, just skip them
-fn ty_ref_to_pub_struct(tcx: TyCtxt<'_>, ty: &hir::Ty<'_>) -> Publicness {
-    if let Some((def_id, def_kind)) = adt_of(ty) {
-        return match def_kind {
-            DefKind::Enum | DefKind::Union => {
-                let ty_is_public = tcx.visibility(def_id).is_public();
-                Publicness::new(ty_is_public, ty_is_public)
-            }
-            DefKind::Struct => {
-                let ty_is_public = tcx.visibility(def_id).is_public();
-                Publicness::new(
-                    ty_is_public,
-                    ty_is_public && struct_all_fields_are_public(tcx, def_id),
-                )
-            }
-            _ => Publicness::new(true, true),
-        };
-    }
-
-    Publicness::new(true, true)
-}
-
 /// Determine if a work from the worklist is coming from a `#[allow]`
 /// or a `#[expect]` of `dead_code`
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
@@ -172,10 +109,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
 
     fn handle_res(&mut self, res: Res) {
         match res {
-            Res::Def(
-                DefKind::Const | DefKind::AssocConst | DefKind::AssocTy | DefKind::TyAlias,
-                def_id,
-            ) => {
+            Res::Def(DefKind::Const | DefKind::AssocConst | DefKind::TyAlias, def_id) => {
                 self.check_def_id(def_id);
             }
             _ if self.in_pat => {}
@@ -294,10 +228,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
         pats: &[hir::PatField<'_>],
     ) {
         let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
-            ty::Adt(adt, _) => {
-                self.check_def_id(adt.did());
-                adt.variant_of_res(res)
-            }
+            ty::Adt(adt, _) => adt.variant_of_res(res),
             _ => span_bug!(lhs.span, "non-ADT in struct pattern"),
         };
         for pat in pats {
@@ -317,10 +248,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
         dotdot: hir::DotDotPos,
     ) {
         let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
-            ty::Adt(adt, _) => {
-                self.check_def_id(adt.did());
-                adt.variant_of_res(res)
-            }
+            ty::Adt(adt, _) => adt.variant_of_res(res),
             _ => {
                 self.tcx.dcx().span_delayed_bug(lhs.span, "non-ADT in tuple struct pattern");
                 return;
@@ -425,6 +353,31 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                 return false;
             }
 
+            // don't ignore impls for Enums and pub Structs whose methods don't have self receiver,
+            // cause external crate may call such methods to construct values of these types
+            if let Some(local_impl_of) = impl_of.as_local()
+                && let Some(local_def_id) = def_id.as_local()
+                && let Some(fn_sig) =
+                    self.tcx.hir().fn_sig_by_hir_id(self.tcx.local_def_id_to_hir_id(local_def_id))
+                && matches!(fn_sig.decl.implicit_self, hir::ImplicitSelfKind::None)
+                && let TyKind::Path(hir::QPath::Resolved(_, path)) =
+                    self.tcx.hir().expect_item(local_impl_of).expect_impl().self_ty.kind
+                && let Res::Def(def_kind, did) = path.res
+            {
+                match def_kind {
+                    // for example, #[derive(Default)] pub struct T(i32);
+                    // external crate can call T::default() to construct T,
+                    // so that don't ignore impl Default for pub Enum and Structs
+                    DefKind::Struct | DefKind::Union if self.tcx.visibility(did).is_public() => {
+                        return false;
+                    }
+                    // don't ignore impl Default for Enums,
+                    // cause we don't know which variant is constructed
+                    DefKind::Enum => return false,
+                    _ => (),
+                };
+            }
+
             if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of)
                 && self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads)
             {
@@ -467,7 +420,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                     intravisit::walk_item(self, item)
                 }
                 hir::ItemKind::ForeignMod { .. } => {}
-                hir::ItemKind::Trait(_, _, _, _, trait_item_refs) => {
+                hir::ItemKind::Trait(..) => {
                     for impl_def_id in self.tcx.all_impls(item.owner_id.to_def_id()) {
                         if let Some(local_def_id) = impl_def_id.as_local()
                             && let ItemKind::Impl(impl_ref) =
@@ -480,12 +433,7 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                             intravisit::walk_path(self, impl_ref.of_trait.unwrap().path);
                         }
                     }
-                    // mark assoc ty live if the trait is live
-                    for trait_item in trait_item_refs {
-                        if let hir::AssocItemKind::Type = trait_item.kind {
-                            self.check_def_id(trait_item.id.owner_id.to_def_id());
-                        }
-                    }
+
                     intravisit::walk_item(self, item)
                 }
                 _ => intravisit::walk_item(self, item),
@@ -502,12 +450,11 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
                             && let ItemKind::Impl(impl_ref) =
                                 self.tcx.hir().expect_item(local_impl_id).kind
                         {
-                            if !ty_ref_to_pub_struct(self.tcx, impl_ref.self_ty)
-                                .ty_and_all_fields_are_public
+                            if !matches!(trait_item.kind, hir::TraitItemKind::Type(..))
+                                && !ty_ref_to_pub_struct(self.tcx, impl_ref.self_ty)
                             {
-                                // skip impl-items of non pure pub ty,
-                                // cause we don't know the ty is constructed or not,
-                                // check these later in `solve_rest_impl_items`
+                                // skip methods of private ty,
+                                // they would be solved in `solve_rest_impl_items`
                                 continue;
                             }
 
@@ -582,25 +529,28 @@ impl<'tcx> MarkSymbolVisitor<'tcx> {
     }
 
     fn impl_item_with_used_self(&mut self, impl_id: hir::ItemId, impl_item_id: LocalDefId) -> bool {
-        if let Some((local_def_id, def_kind)) =
-            adt_of(self.tcx.hir().item(impl_id).expect_impl().self_ty)
+        if let TyKind::Path(hir::QPath::Resolved(_, path)) =
+            self.tcx.hir().item(impl_id).expect_impl().self_ty.kind
+            && let Res::Def(def_kind, def_id) = path.res
+            && let Some(local_def_id) = def_id.as_local()
             && matches!(def_kind, DefKind::Struct | DefKind::Enum | DefKind::Union)
         {
+            if self.tcx.visibility(impl_item_id).is_public() {
+                // for the public method, we don't know the trait item is used or not,
+                // so we mark the method live if the self is used
+                return self.live_symbols.contains(&local_def_id);
+            }
+
             if let Some(trait_item_id) = self.tcx.associated_item(impl_item_id).trait_item_def_id
                 && let Some(local_id) = trait_item_id.as_local()
             {
-                // for the local impl item, we can know the trait item is used or not,
+                // for the private method, we can know the trait item is used or not,
                 // so we mark the method live if the self is used and the trait item is used
-                self.live_symbols.contains(&local_id) && self.live_symbols.contains(&local_def_id)
-            } else {
-                // for the foreign method and inherent pub method,
-                // we don't know the trait item or the method is used or not,
-                // so we mark the method live if the self is used
-                self.live_symbols.contains(&local_def_id)
+                return self.live_symbols.contains(&local_id)
+                    && self.live_symbols.contains(&local_def_id);
             }
-        } else {
-            false
         }
+        false
     }
 }
 
@@ -686,9 +636,6 @@ impl<'tcx> Visitor<'tcx> for MarkSymbolVisitor<'tcx> {
                 self.handle_field_pattern_match(pat, res, fields);
             }
             PatKind::Path(ref qpath) => {
-                if let ty::Adt(adt, _) = self.typeck_results().node_type(pat.hir_id).kind() {
-                    self.check_def_id(adt.did());
-                }
                 let res = self.typeck_results().qpath_res(qpath, pat.hir_id);
                 self.handle_res(res);
             }
@@ -825,9 +772,7 @@ fn check_item<'tcx>(
                 .iter()
                 .filter_map(|def_id| def_id.as_local());
 
-            let self_ty = tcx.hir().item(id).expect_impl().self_ty;
-            let Publicness { ty_is_public, ty_and_all_fields_are_public } =
-                ty_ref_to_pub_struct(tcx, self_ty);
+            let ty_is_pub = ty_ref_to_pub_struct(tcx, tcx.hir().item(id).expect_impl().self_ty);
 
             // And we access the Map here to get HirId from LocalDefId
             for local_def_id in local_def_ids {
@@ -843,19 +788,18 @@ fn check_item<'tcx>(
                 // for trait impl blocks,
                 // mark the method live if the self_ty is public,
                 // or the method is public and may construct self
-                if tcx.visibility(local_def_id).is_public()
-                    && (ty_and_all_fields_are_public || (ty_is_public && may_construct_self))
+                if of_trait
+                    && (!matches!(tcx.def_kind(local_def_id), DefKind::AssocFn)
+                        || tcx.visibility(local_def_id).is_public()
+                            && (ty_is_pub || may_construct_self))
                 {
-                    // if the impl item is public,
-                    // and the ty may be constructed or can be constructed in foreign crates,
-                    // mark the impl item live
                     worklist.push((local_def_id, ComesFromAllowExpect::No));
                 } else if let Some(comes_from_allow) =
                     has_allow_dead_code_or_lang_attr(tcx, local_def_id)
                 {
                     worklist.push((local_def_id, comes_from_allow));
-                } else if of_trait || tcx.visibility(local_def_id).is_public() && ty_is_public {
-                    // private impl items of traits || public impl items not constructs self
+                } else if of_trait {
+                    // private method || public method not constructs self
                     unsolved_impl_items.push((id, local_def_id));
                 }
             }
@@ -881,13 +825,10 @@ fn check_trait_item(
     worklist: &mut Vec<(LocalDefId, ComesFromAllowExpect)>,
     id: hir::TraitItemId,
 ) {
-    use hir::TraitItemKind::{Const, Fn, Type};
-    if matches!(
-        tcx.def_kind(id.owner_id),
-        DefKind::AssocConst | DefKind::AssocTy | DefKind::AssocFn
-    ) {
+    use hir::TraitItemKind::{Const, Fn};
+    if matches!(tcx.def_kind(id.owner_id), DefKind::AssocConst | DefKind::AssocFn) {
         let trait_item = tcx.hir().trait_item(id);
-        if matches!(trait_item.kind, Const(_, Some(_)) | Type(_, Some(_)) | Fn(..))
+        if matches!(trait_item.kind, Const(_, Some(_)) | Fn(..))
             && let Some(comes_from_allow) =
                 has_allow_dead_code_or_lang_attr(tcx, trait_item.owner_id.def_id)
         {
@@ -925,14 +866,6 @@ fn create_and_seed_worklist(
             effective_vis
                 .is_public_at_level(Level::Reachable)
                 .then_some(id)
-                .filter(|&id|
-                    // checks impls, impl-items and pub structs with all public fields later
-                    match tcx.def_kind(id) {
-                        DefKind::Impl { .. } => false,
-                        DefKind::AssocConst | DefKind::AssocTy | DefKind::AssocFn => !matches!(tcx.associated_item(id).container, AssocItemContainer::ImplContainer),
-                        DefKind::Struct => struct_all_fields_are_public(tcx, id) || has_allow_dead_code_or_lang_attr(tcx, id).is_some(),
-                        _ => true
-                    })
                 .map(|id| (id, ComesFromAllowExpect::No))
         })
         // Seed entry point
@@ -1216,7 +1149,6 @@ impl<'tcx> DeadVisitor<'tcx> {
         }
         match self.tcx.def_kind(def_id) {
             DefKind::AssocConst
-            | DefKind::AssocTy
             | DefKind::AssocFn
             | DefKind::Fn
             | DefKind::Static { .. }
@@ -1258,14 +1190,10 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
             || (def_kind == DefKind::Trait && live_symbols.contains(&item.owner_id.def_id))
         {
             for &def_id in tcx.associated_item_def_ids(item.owner_id.def_id) {
-                // We have diagnosed unused assocs in traits
+                // We have diagnosed unused methods in traits
                 if matches!(def_kind, DefKind::Impl { of_trait: true })
-                    && matches!(tcx.def_kind(def_id), DefKind::AssocConst | DefKind::AssocTy | DefKind::AssocFn)
-                    // skip unused public inherent methods,
-                    // cause we have diagnosed unconstructed struct
-                    || matches!(def_kind, DefKind::Impl { of_trait: false })
-                        && tcx.visibility(def_id).is_public()
-                        && ty_ref_to_pub_struct(tcx, tcx.hir().item(item).expect_impl().self_ty).ty_is_public
+                    && tcx.def_kind(def_id) == DefKind::AssocFn
+                    || def_kind == DefKind::Trait && tcx.def_kind(def_id) != DefKind::AssocFn
                 {
                     continue;
                 }
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index c4f3c8a0d6c..36dfc40e762 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -636,6 +636,13 @@ pub struct Confusables {
     pub attr_span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_coroutine_on_non_closure)]
+pub struct CoroutineOnNonClosure {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_empty_confusables)]
 pub(crate) struct EmptyConfusables {
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 761d6acdbae..ca3efc11201 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -588,7 +588,7 @@ pub fn report_cycle<'a>(
         cycle_stack,
         stack_bottom: stack[0].query.description.to_owned(),
         alias,
-        cycle_usage: cycle_usage,
+        cycle_usage,
         stack_count,
         note_span: (),
     };
diff --git a/compiler/rustc_session/src/filesearch.rs b/compiler/rustc_session/src/filesearch.rs
index 0c3ec36fed5..63ca5fefd9f 100644
--- a/compiler/rustc_session/src/filesearch.rs
+++ b/compiler/rustc_session/src/filesearch.rs
@@ -19,6 +19,11 @@ pub struct FileSearch<'a> {
 }
 
 impl<'a> FileSearch<'a> {
+    pub fn cli_search_paths(&self) -> impl Iterator<Item = &'a SearchPath> {
+        let kind = self.kind;
+        self.cli_search_paths.iter().filter(move |sp| sp.kind.matches(kind))
+    }
+
     pub fn search_paths(&self) -> impl Iterator<Item = &'a SearchPath> {
         let kind = self.kind;
         self.cli_search_paths
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index e8563f50158..9977fa7425a 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1705,6 +1705,7 @@ symbols! {
         self_in_typedefs,
         self_struct_ctor,
         semitransparent,
+        sha512_sm_x86,
         shadow_call_stack,
         shl,
         shl_assign,
diff --git a/compiler/rustc_target/src/target_features.rs b/compiler/rustc_target/src/target_features.rs
index 532507cb182..e52f2fc06df 100644
--- a/compiler/rustc_target/src/target_features.rs
+++ b/compiler/rustc_target/src/target_features.rs
@@ -238,6 +238,9 @@ const X86_ALLOWED_FEATURES: &[(&str, Stability)] = &[
     ("rdseed", Stable),
     ("rtm", Unstable(sym::rtm_target_feature)),
     ("sha", Stable),
+    ("sha512", Unstable(sym::sha512_sm_x86)),
+    ("sm3", Unstable(sym::sha512_sm_x86)),
+    ("sm4", Unstable(sym::sha512_sm_x86)),
     ("sse", Stable),
     ("sse2", Stable),
     ("sse3", Stable),
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index ef40d3b203f..38f50955b12 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -1173,6 +1173,7 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     /// ```
     ///
     /// [memory layout]: self#memory-layout
+    #[must_use = "losing the pointer will leak memory"]
     #[stable(feature = "box_raw", since = "1.4.0")]
     #[inline]
     pub fn into_raw(b: Self) -> *mut T {
@@ -1226,6 +1227,7 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     /// ```
     ///
     /// [memory layout]: self#memory-layout
+    #[must_use = "losing the pointer will leak memory"]
     #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index bc0874fc13f..13d218e43a7 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -1372,6 +1372,7 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
     /// let x = unsafe { Rc::from_raw_in(ptr, alloc) };
     /// assert_eq!(&*x, "hello");
     /// ```
+    #[must_use = "losing the pointer will leak memory"]
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub fn into_raw_with_allocator(this: Self) -> (*const T, A) {
         let this = mem::ManuallyDrop::new(this);
@@ -3107,6 +3108,7 @@ impl<T: ?Sized, A: Allocator> Weak<T, A> {
     ///
     /// [`from_raw_in`]: Weak::from_raw_in
     /// [`as_ptr`]: Weak::as_ptr
+    #[must_use = "losing the pointer will leak memory"]
     #[inline]
     #[unstable(feature = "allocator_api", issue = "32838")]
     pub fn into_raw_with_allocator(self) -> (*const T, A) {
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 01fe950cf3f..124230812df 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -900,7 +900,7 @@ impl String {
     /// let rebuilt = unsafe { String::from_raw_parts(ptr, len, cap) };
     /// assert_eq!(rebuilt, "hello");
     /// ```
-    #[must_use = "`self` will be dropped if the result is not used"]
+    #[must_use = "losing the pointer will leak memory"]
     #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
     pub fn into_raw_parts(self) -> (*mut u8, usize, usize) {
         self.vec.into_raw_parts()
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index dfd22204c81..b4e0bc5fcbe 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -878,6 +878,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// };
     /// assert_eq!(rebuilt, [4294967295, 0, 1]);
     /// ```
+    #[must_use = "losing the pointer will leak memory"]
     #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
     pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
         let mut me = ManuallyDrop::new(self);
@@ -921,6 +922,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// };
     /// assert_eq!(rebuilt, [4294967295, 0, 1]);
     /// ```
+    #[must_use = "losing the pointer will leak memory"]
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
     pub fn into_raw_parts_with_alloc(self) -> (*mut T, usize, usize, A) {
diff --git a/library/core/src/arch.rs b/library/core/src/arch.rs
index 31d6bc36fc8..d681bd124fe 100644
--- a/library/core/src/arch.rs
+++ b/library/core/src/arch.rs
@@ -4,6 +4,15 @@
 #[stable(feature = "simd_arch", since = "1.27.0")]
 pub use crate::core_arch::arch::*;
 
+#[cfg(bootstrap)]
+#[allow(dead_code)]
+#[unstable(feature = "sha512_sm_x86", issue = "126624")]
+fn dummy() {
+    // AArch64 also has a target feature named `sm4`, so we need `#![feature(sha512_sm_x86)]` in lib.rs
+    // But as the bootstrap compiler doesn't know about this feature yet, we need to convert it to a
+    // library feature until bootstrap gets bumped
+}
+
 /// Inline assembly.
 ///
 /// Refer to [Rust By Example] for a usage guide and the [reference] for
diff --git a/library/core/src/default.rs b/library/core/src/default.rs
index 4524b352ec8..5cacedcb241 100644
--- a/library/core/src/default.rs
+++ b/library/core/src/default.rs
@@ -103,6 +103,7 @@ use crate::ascii::Char as AsciiChar;
 /// ```
 #[cfg_attr(not(test), rustc_diagnostic_item = "Default")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), rustc_trivial_field_reads)]
 pub trait Default: Sized {
     /// Returns the "default value" for a type.
     ///
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 13c7f0855d8..e9eacbcd25a 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -2436,11 +2436,13 @@ extern "rust-intrinsic" {
     ///
     /// # Safety
     ///
-    /// It's UB to call this if any of the *bytes* in `*a` or `*b` are uninitialized or carry a
-    /// pointer value.
+    /// It's UB to call this if any of the *bytes* in `*a` or `*b` are uninitialized.
     /// Note that this is a stricter criterion than just the *values* being
     /// fully-initialized: if `T` has padding, it's UB to call this intrinsic.
     ///
+    /// At compile-time, it is furthermore UB to call this if any of the bytes
+    /// in `*a` or `*b` have provenance.
+    ///
     /// (The implementation is allowed to branch on the results of comparisons,
     /// which is UB if any of their inputs are `undef`.)
     #[rustc_const_unstable(feature = "const_intrinsic_raw_eq", issue = "none")]
diff --git a/library/core/src/iter/sources/repeat_n.rs b/library/core/src/iter/sources/repeat_n.rs
index 8390dab8e54..4c4ae39f836 100644
--- a/library/core/src/iter/sources/repeat_n.rs
+++ b/library/core/src/iter/sources/repeat_n.rs
@@ -114,19 +114,12 @@ impl<A: Clone> Iterator for RepeatN<A> {
 
     #[inline]
     fn next(&mut self) -> Option<A> {
-        if self.count == 0 {
-            return None;
-        }
-
-        self.count -= 1;
-        Some(if self.count == 0 {
-            // SAFETY: the check above ensured that the count used to be non-zero,
-            // so element hasn't been dropped yet, and we just lowered the count to
-            // zero so it won't be dropped later, and thus it's okay to take it here.
-            unsafe { ManuallyDrop::take(&mut self.element) }
+        if self.count > 0 {
+            // SAFETY: Just checked it's not empty
+            unsafe { Some(self.next_unchecked()) }
         } else {
-            A::clone(&self.element)
-        })
+            None
+        }
     }
 
     #[inline]
@@ -194,4 +187,18 @@ impl<A: Clone> FusedIterator for RepeatN<A> {}
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<A: Clone> TrustedLen for RepeatN<A> {}
 #[unstable(feature = "trusted_len_next_unchecked", issue = "37572")]
-impl<A: Clone> UncheckedIterator for RepeatN<A> {}
+impl<A: Clone> UncheckedIterator for RepeatN<A> {
+    #[inline]
+    unsafe fn next_unchecked(&mut self) -> Self::Item {
+        // SAFETY: The caller promised the iterator isn't empty
+        self.count = unsafe { self.count.unchecked_sub(1) };
+        if self.count == 0 {
+            // SAFETY: the check above ensured that the count used to be non-zero,
+            // so element hasn't been dropped yet, and we just lowered the count to
+            // zero so it won't be dropped later, and thus it's okay to take it here.
+            unsafe { ManuallyDrop::take(&mut self.element) }
+        } else {
+            A::clone(&self.element)
+        }
+    }
+}
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 0917631e045..9306581dca9 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -260,6 +260,7 @@
 #![feature(powerpc_target_feature)]
 #![feature(riscv_target_feature)]
 #![feature(rtm_target_feature)]
+#![feature(sha512_sm_x86)]
 #![feature(sse4a_target_feature)]
 #![feature(tbm_target_feature)]
 #![feature(wasm_target_feature)]
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index 0b0a416ea24..45dc828eb2e 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -7,7 +7,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use crate::cmp::Ordering::{self, Equal, Greater, Less};
-use crate::intrinsics::{exact_div, unchecked_sub};
+use crate::intrinsics::{exact_div, select_unpredictable, unchecked_sub};
 use crate::mem::{self, SizedTypeProperties};
 use crate::num::NonZero;
 use crate::ops::{Bound, OneSidedRange, Range, RangeBounds};
@@ -2770,41 +2770,54 @@ impl<T> [T] {
     where
         F: FnMut(&'a T) -> Ordering,
     {
-        // INVARIANTS:
-        // - 0 <= left <= left + size = right <= self.len()
-        // - f returns Less for everything in self[..left]
-        // - f returns Greater for everything in self[right..]
         let mut size = self.len();
-        let mut left = 0;
-        let mut right = size;
-        while left < right {
-            let mid = left + size / 2;
+        if size == 0 {
+            return Err(0);
+        }
+        let mut base = 0usize;
 
-            // SAFETY: the while condition means `size` is strictly positive, so
-            // `size/2 < size`. Thus `left + size/2 < left + size`, which
-            // coupled with the `left + size <= self.len()` invariant means
-            // we have `left + size/2 < self.len()`, and this is in-bounds.
+        // This loop intentionally doesn't have an early exit if the comparison
+        // returns Equal. We want the number of loop iterations to depend *only*
+        // on the size of the input slice so that the CPU can reliably predict
+        // the loop count.
+        while size > 1 {
+            let half = size / 2;
+            let mid = base + half;
+
+            // SAFETY: the call is made safe by the following inconstants:
+            // - `mid >= 0`: by definition
+            // - `mid < size`: `mid = size / 2 + size / 4 + size / 8 ...`
             let cmp = f(unsafe { self.get_unchecked(mid) });
 
-            // This control flow produces conditional moves, which results in
-            // fewer branches and instructions than if/else or matching on
-            // cmp::Ordering.
-            // This is x86 asm for u8: https://rust.godbolt.org/z/698eYffTx.
-            left = if cmp == Less { mid + 1 } else { left };
-            right = if cmp == Greater { mid } else { right };
-            if cmp == Equal {
-                // SAFETY: same as the `get_unchecked` above
-                unsafe { hint::assert_unchecked(mid < self.len()) };
-                return Ok(mid);
-            }
+            // Binary search interacts poorly with branch prediction, so force
+            // the compiler to use conditional moves if supported by the target
+            // architecture.
+            base = select_unpredictable(cmp == Greater, base, mid);
 
-            size = right - left;
+            // This is imprecise in the case where `size` is odd and the
+            // comparison returns Greater: the mid element still gets included
+            // by `size` even though it's known to be larger than the element
+            // being searched for.
+            //
+            // This is fine though: we gain more performance by keeping the
+            // loop iteration count invariant (and thus predictable) than we
+            // lose from considering one additional element.
+            size -= half;
         }
 
-        // SAFETY: directly true from the overall invariant.
-        // Note that this is `<=`, unlike the assume in the `Ok` path.
-        unsafe { hint::assert_unchecked(left <= self.len()) };
-        Err(left)
+        // SAFETY: base is always in [0, size) because base <= mid.
+        let cmp = f(unsafe { self.get_unchecked(base) });
+        if cmp == Equal {
+            // SAFETY: same as the `get_unchecked` above.
+            unsafe { hint::assert_unchecked(base < self.len()) };
+            Ok(base)
+        } else {
+            let result = base + (cmp == Less) as usize;
+            // SAFETY: same as the `get_unchecked` above.
+            // Note that this is `<=`, unlike the assume in the `Ok` path.
+            unsafe { hint::assert_unchecked(result <= self.len()) };
+            Err(result)
+        }
     }
 
     /// Binary searches this slice with a key extraction function.
diff --git a/library/core/tests/slice.rs b/library/core/tests/slice.rs
index acabedcdc26..cdefb5d3eb2 100644
--- a/library/core/tests/slice.rs
+++ b/library/core/tests/slice.rs
@@ -69,13 +69,13 @@ fn test_binary_search() {
     assert_eq!(b.binary_search(&8), Err(5));
 
     let b = [(); usize::MAX];
-    assert_eq!(b.binary_search(&()), Ok(usize::MAX / 2));
+    assert_eq!(b.binary_search(&()), Ok(usize::MAX - 1));
 }
 
 #[test]
 fn test_binary_search_by_overflow() {
     let b = [(); usize::MAX];
-    assert_eq!(b.binary_search_by(|_| Ordering::Equal), Ok(usize::MAX / 2));
+    assert_eq!(b.binary_search_by(|_| Ordering::Equal), Ok(usize::MAX - 1));
     assert_eq!(b.binary_search_by(|_| Ordering::Greater), Err(0));
     assert_eq!(b.binary_search_by(|_| Ordering::Less), Err(usize::MAX));
 }
@@ -87,13 +87,13 @@ fn test_binary_search_implementation_details() {
     let b = [1, 1, 2, 2, 3, 3, 3];
     assert_eq!(b.binary_search(&1), Ok(1));
     assert_eq!(b.binary_search(&2), Ok(3));
-    assert_eq!(b.binary_search(&3), Ok(5));
+    assert_eq!(b.binary_search(&3), Ok(6));
     let b = [1, 1, 1, 1, 1, 3, 3, 3, 3];
     assert_eq!(b.binary_search(&1), Ok(4));
-    assert_eq!(b.binary_search(&3), Ok(7));
+    assert_eq!(b.binary_search(&3), Ok(8));
     let b = [1, 1, 1, 1, 3, 3, 3, 3, 3];
-    assert_eq!(b.binary_search(&1), Ok(2));
-    assert_eq!(b.binary_search(&3), Ok(4));
+    assert_eq!(b.binary_search(&1), Ok(3));
+    assert_eq!(b.binary_search(&3), Ok(8));
 }
 
 #[test]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 6bd9c59a949..05e33d47bac 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -269,10 +269,6 @@
 #![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
 #![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
 #![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
-#![cfg_attr(
-    all(any(target_arch = "x86_64", target_arch = "x86"), target_os = "uefi"),
-    feature(stdarch_x86_has_cpuid)
-)]
 //
 // Language features:
 // tidy-alphabetical-start
@@ -302,6 +298,7 @@
 #![feature(let_chains)]
 #![feature(link_cfg)]
 #![feature(linkage)]
+#![feature(macro_metavar_expr_concat)]
 #![feature(min_exhaustive_patterns)]
 #![feature(min_specialization)]
 #![feature(must_not_suspend)]
@@ -670,7 +667,6 @@ mod panicking;
 #[allow(dead_code, unused_attributes, fuzzy_provenance_casts, unsafe_op_in_unsafe_fn)]
 mod backtrace_rs;
 
-// Re-export macros defined in core.
 #[unstable(feature = "cfg_match", issue = "115585")]
 pub use core::cfg_match;
 #[unstable(
@@ -689,6 +685,7 @@ pub use core::{
     env, file, format_args, format_args_nl, include, include_bytes, include_str, line, log_syntax,
     module_path, option_env, stringify, trace_macros,
 };
+// Re-export macros defined in core.
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated, deprecated_in_future)]
 pub use core::{
diff --git a/library/std/src/os/fd/raw.rs b/library/std/src/os/fd/raw.rs
index 1e6ecd7d7a6..0d99d5492a2 100644
--- a/library/std/src/os/fd/raw.rs
+++ b/library/std/src/os/fd/raw.rs
@@ -138,6 +138,7 @@ pub trait IntoRawFd {
     /// let raw_fd: RawFd = f.into_raw_fd();
     /// # Ok::<(), io::Error>(())
     /// ```
+    #[must_use = "losing the raw file descriptor may leak resources"]
     #[stable(feature = "into_raw_os", since = "1.4.0")]
     fn into_raw_fd(self) -> RawFd;
 }
diff --git a/library/std/src/os/solid/io.rs b/library/std/src/os/solid/io.rs
index 9e89d9fbc1b..2d18f339615 100644
--- a/library/std/src/os/solid/io.rs
+++ b/library/std/src/os/solid/io.rs
@@ -342,6 +342,7 @@ pub trait IntoRawFd {
     /// This function **transfers ownership** of the underlying file descriptor
     /// to the caller. Callers are then the unique owners of the file descriptor
     /// and must close the descriptor once it's no longer needed.
+    #[must_use = "losing the raw file descriptor may leak resources"]
     fn into_raw_fd(self) -> RawFd;
 }
 
diff --git a/library/std/src/os/windows/io/raw.rs b/library/std/src/os/windows/io/raw.rs
index 4ba07e3d2af..6658248d574 100644
--- a/library/std/src/os/windows/io/raw.rs
+++ b/library/std/src/os/windows/io/raw.rs
@@ -85,6 +85,7 @@ pub trait IntoRawHandle {
     /// However, transferring ownership is not strictly required. Use a
     /// `Into<OwnedHandle>::into` implementation for an API which strictly
     /// transfers ownership.
+    #[must_use = "losing the raw handle may leak resources"]
     #[stable(feature = "into_raw_os", since = "1.4.0")]
     fn into_raw_handle(self) -> RawHandle;
 }
@@ -228,6 +229,7 @@ pub trait IntoRawSocket {
     /// However, transferring ownership is not strictly required. Use a
     /// `Into<OwnedSocket>::into` implementation for an API which strictly
     /// transfers ownership.
+    #[must_use = "losing the raw socket may leak resources"]
     #[stable(feature = "into_raw_os", since = "1.4.0")]
     fn into_raw_socket(self) -> RawSocket;
 }
diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs
index 2ca9256715c..4c496ade81c 100644
--- a/library/std/src/panic.rs
+++ b/library/std/src/panic.rs
@@ -463,11 +463,10 @@ static SHOULD_CAPTURE: AtomicU8 = AtomicU8::new(0);
 /// environment variable; see the details in [`get_backtrace_style`].
 #[unstable(feature = "panic_backtrace_config", issue = "93346")]
 pub fn set_backtrace_style(style: BacktraceStyle) {
-    if !cfg!(feature = "backtrace") {
-        // If the `backtrace` feature of this crate isn't enabled, skip setting.
-        return;
+    if cfg!(feature = "backtrace") {
+        // If the `backtrace` feature of this crate is enabled, set the backtrace style.
+        SHOULD_CAPTURE.store(style.as_u8(), Ordering::Release);
     }
-    SHOULD_CAPTURE.store(style.as_u8(), Ordering::Release);
 }
 
 /// Checks whether the standard library's panic hook will capture and print a
@@ -503,21 +502,13 @@ pub fn get_backtrace_style() -> Option<BacktraceStyle> {
         return Some(style);
     }
 
-    let format = crate::env::var_os("RUST_BACKTRACE")
-        .map(|x| {
-            if &x == "0" {
-                BacktraceStyle::Off
-            } else if &x == "full" {
-                BacktraceStyle::Full
-            } else {
-                BacktraceStyle::Short
-            }
-        })
-        .unwrap_or(if crate::sys::FULL_BACKTRACE_DEFAULT {
-            BacktraceStyle::Full
-        } else {
-            BacktraceStyle::Off
-        });
+    let format = match crate::env::var_os("RUST_BACKTRACE") {
+        Some(x) if &x == "0" => BacktraceStyle::Off,
+        Some(x) if &x == "full" => BacktraceStyle::Full,
+        Some(_) => BacktraceStyle::Short,
+        None if crate::sys::FULL_BACKTRACE_DEFAULT => BacktraceStyle::Full,
+        None => BacktraceStyle::Off,
+    };
     set_backtrace_style(format);
     Some(format)
 }
diff --git a/library/std/src/sys/pal/sgx/thread.rs b/library/std/src/sys/pal/sgx/thread.rs
index df65d1cc8fc..cecd53c352c 100644
--- a/library/std/src/sys/pal/sgx/thread.rs
+++ b/library/std/src/sys/pal/sgx/thread.rs
@@ -1,4 +1,5 @@
 #![cfg_attr(test, allow(dead_code))] // why is this necessary?
+
 use super::abi::usercalls;
 use super::unsupported;
 use crate::ffi::CStr;
diff --git a/library/std/src/sys/pal/uefi/time.rs b/library/std/src/sys/pal/uefi/time.rs
index a97d69f997b..495ff2dc930 100644
--- a/library/std/src/sys/pal/uefi/time.rs
+++ b/library/std/src/sys/pal/uefi/time.rs
@@ -175,10 +175,6 @@ pub(crate) mod instant_internal {
 
     #[cfg(target_arch = "x86_64")]
     fn timestamp_rdtsc() -> Option<Duration> {
-        if !crate::arch::x86_64::has_cpuid() {
-            return None;
-        }
-
         static FREQUENCY: crate::sync::OnceLock<u64> = crate::sync::OnceLock::new();
 
         // Get Frequency in Mhz
@@ -200,10 +196,6 @@ pub(crate) mod instant_internal {
 
     #[cfg(target_arch = "x86")]
     fn timestamp_rdtsc() -> Option<Duration> {
-        if !crate::arch::x86::has_cpuid() {
-            return None;
-        }
-
         static FREQUENCY: crate::sync::OnceLock<u64> = crate::sync::OnceLock::new();
 
         let freq = FREQUENCY
diff --git a/library/std/src/sys/pal/unix/kernel_copy.rs b/library/std/src/sys/pal/unix/kernel_copy.rs
index 652b2e1feb7..a671383cb79 100644
--- a/library/std/src/sys/pal/unix/kernel_copy.rs
+++ b/library/std/src/sys/pal/unix/kernel_copy.rs
@@ -60,6 +60,7 @@ use crate::net::TcpStream;
 use crate::os::unix::fs::FileTypeExt;
 use crate::os::unix::io::{AsRawFd, FromRawFd, RawFd};
 use crate::os::unix::net::UnixStream;
+use crate::pipe::{PipeReader, PipeWriter};
 use crate::process::{ChildStderr, ChildStdin, ChildStdout};
 use crate::ptr;
 use crate::sync::atomic::{AtomicBool, AtomicU8, Ordering};
@@ -405,6 +406,30 @@ impl CopyWrite for &UnixStream {
     }
 }
 
+impl CopyRead for PipeReader {
+    fn properties(&self) -> CopyParams {
+        CopyParams(FdMeta::Pipe, Some(self.as_raw_fd()))
+    }
+}
+
+impl CopyRead for &PipeReader {
+    fn properties(&self) -> CopyParams {
+        CopyParams(FdMeta::Pipe, Some(self.as_raw_fd()))
+    }
+}
+
+impl CopyWrite for PipeWriter {
+    fn properties(&self) -> CopyParams {
+        CopyParams(FdMeta::Pipe, Some(self.as_raw_fd()))
+    }
+}
+
+impl CopyWrite for &PipeWriter {
+    fn properties(&self) -> CopyParams {
+        CopyParams(FdMeta::Pipe, Some(self.as_raw_fd()))
+    }
+}
+
 impl CopyWrite for ChildStdin {
     fn properties(&self) -> CopyParams {
         CopyParams(FdMeta::Pipe, Some(self.as_raw_fd()))
diff --git a/library/std/src/sys/pal/unix/pipe.rs b/library/std/src/sys/pal/unix/pipe.rs
index 8762af614f1..f0ebc767bad 100644
--- a/library/std/src/sys/pal/unix/pipe.rs
+++ b/library/std/src/sys/pal/unix/pipe.rs
@@ -47,6 +47,8 @@ pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
 }
 
 impl AnonPipe {
+    #[allow(dead_code)]
+    // FIXME: This function seems legitimately unused.
     pub fn try_clone(&self) -> io::Result<Self> {
         self.0.duplicate().map(Self)
     }
@@ -85,6 +87,8 @@ impl AnonPipe {
         self.0.is_write_vectored()
     }
 
+    #[allow(dead_code)]
+    // FIXME: This function seems legitimately unused.
     pub fn as_file_desc(&self) -> &FileDesc {
         &self.0
     }
diff --git a/library/std/src/sys/pal/unix/weak.rs b/library/std/src/sys/pal/unix/weak.rs
index b1b6aae757c..35762f5a53b 100644
--- a/library/std/src/sys/pal/unix/weak.rs
+++ b/library/std/src/sys/pal/unix/weak.rs
@@ -168,14 +168,7 @@ pub(crate) macro syscall {
             if let Some(fun) = $name.get() {
                 fun($($arg_name),*)
             } else {
-                // This looks like a hack, but concat_idents only accepts idents
-                // (not paths).
-                use libc::*;
-
-                syscall(
-                    concat_idents!(SYS_, $name),
-                    $($arg_name),*
-                ) as $ret
+                libc::syscall(libc::${concat(SYS_, $name)}, $($arg_name),*) as $ret
             }
         }
     )
@@ -185,14 +178,7 @@ pub(crate) macro syscall {
 pub(crate) macro raw_syscall {
     (fn $name:ident($($arg_name:ident: $t:ty),*) -> $ret:ty) => (
         unsafe fn $name($($arg_name:$t),*) -> $ret {
-            // This looks like a hack, but concat_idents only accepts idents
-            // (not paths).
-            use libc::*;
-
-            syscall(
-                concat_idents!(SYS_, $name),
-                $($arg_name),*
-            ) as $ret
+            libc::syscall(libc::${concat(SYS_, $name)}, $($arg_name),*) as $ret
         }
     )
 }
diff --git a/library/std/src/sys/pal/windows/net.rs b/library/std/src/sys/pal/windows/net.rs
index e27fdb72256..ce995f5ed5a 100644
--- a/library/std/src/sys/pal/windows/net.rs
+++ b/library/std/src/sys/pal/windows/net.rs
@@ -21,6 +21,7 @@ pub mod netc {
     //!
     //! Some Windows API types are not quite what's expected by our cross-platform
     //! net code. E.g. naming differences or different pointer types.
+
     use core::ffi::{c_char, c_int, c_uint, c_ulong, c_ushort, c_void};
 
     use crate::sys::c::{self, ADDRESS_FAMILY, ADDRINFOA, SOCKADDR, SOCKET};
diff --git a/library/std/src/sys/pal/windows/process.rs b/library/std/src/sys/pal/windows/process.rs
index c285e1530a5..06eae5a07b0 100644
--- a/library/std/src/sys/pal/windows/process.rs
+++ b/library/std/src/sys/pal/windows/process.rs
@@ -564,7 +564,7 @@ impl Stdio {
             Ok(io) => unsafe {
                 let io = Handle::from_raw_handle(io);
                 let ret = io.duplicate(0, true, c::DUPLICATE_SAME_ACCESS);
-                io.into_raw_handle();
+                let _ = io.into_raw_handle(); // Don't close the handle
                 ret
             },
             // If no stdio handle is available, then propagate the null value.
diff --git a/library/std/src/sys/pal/windows/stdio.rs b/library/std/src/sys/pal/windows/stdio.rs
index dc63a2219c3..575f2250eb9 100644
--- a/library/std/src/sys/pal/windows/stdio.rs
+++ b/library/std/src/sys/pal/windows/stdio.rs
@@ -94,7 +94,7 @@ fn write(handle_id: u32, data: &[u8], incomplete_utf8: &mut IncompleteUtf8) -> i
         unsafe {
             let handle = Handle::from_raw_handle(handle);
             let ret = handle.write(data);
-            handle.into_raw_handle(); // Don't close the handle
+            let _ = handle.into_raw_handle(); // Don't close the handle
             return ret;
         }
     }
@@ -243,7 +243,7 @@ impl io::Read for Stdin {
             unsafe {
                 let handle = Handle::from_raw_handle(handle);
                 let ret = handle.read(buf);
-                handle.into_raw_handle(); // Don't close the handle
+                let _ = handle.into_raw_handle(); // Don't close the handle
                 return ret;
             }
         }
diff --git a/src/bootstrap/Cargo.lock b/src/bootstrap/Cargo.lock
index de0924c0f42..60453764d82 100644
--- a/src/bootstrap/Cargo.lock
+++ b/src/bootstrap/Cargo.lock
@@ -65,7 +65,7 @@ dependencies = [
  "termcolor",
  "toml",
  "walkdir",
- "windows",
+ "windows 0.52.0",
  "xz2",
 ]
 
@@ -378,12 +378,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "once_cell"
-version = "1.19.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
-
 [[package]]
 name = "opener"
 version = "0.5.2"
@@ -549,16 +543,15 @@ dependencies = [
 
 [[package]]
 name = "sysinfo"
-version = "0.30.5"
+version = "0.31.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fb4f3438c8f6389c864e61221cbc97e9bca98b4daf39a5beb7bea660f528bb2"
+checksum = "d4115055da5f572fff541dd0c4e61b0262977f453cc9fe04be83aba25a89bdab"
 dependencies = [
- "cfg-if",
  "core-foundation-sys",
  "libc",
+ "memchr",
  "ntapi",
- "once_cell",
- "windows",
+ "windows 0.57.0",
 ]
 
 [[package]]
@@ -655,7 +648,17 @@ version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e48a53791691ab099e5e2ad123536d0fff50652600abaf43bbf952894110d0be"
 dependencies = [
- "windows-core",
+ "windows-core 0.52.0",
+ "windows-targets",
+]
+
+[[package]]
+name = "windows"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12342cb4d8e3b046f3d80effd474a7a02447231330ef77d71daa6fbc40681143"
+dependencies = [
+ "windows-core 0.57.0",
  "windows-targets",
 ]
 
@@ -668,6 +671,49 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "windows-core"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2ed2439a290666cd67ecce2b0ffaad89c2a56b976b736e6ece670297897832d"
+dependencies = [
+ "windows-implement",
+ "windows-interface",
+ "windows-result",
+ "windows-targets",
+]
+
+[[package]]
+name = "windows-implement"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9107ddc059d5b6fbfbffdfa7a7fe3e22a226def0b2608f72e9d552763d3e1ad7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "windows-interface"
+version = "0.57.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29bee4b38ea3cde66011baa44dba677c432a78593e202392d1e9070cf2a7fca7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "windows-result"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e383302e8ec8515204254685643de10811af0ed97ea37210dc26fb0032647f8"
+dependencies = [
+ "windows-targets",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"
@@ -679,13 +725,14 @@ dependencies = [
 
 [[package]]
 name = "windows-targets"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a18201040b24831fbb9e4eb208f8892e1f50a37feb53cc7ff887feb8f50e7cd"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
 dependencies = [
  "windows_aarch64_gnullvm",
  "windows_aarch64_msvc",
  "windows_i686_gnu",
+ "windows_i686_gnullvm",
  "windows_i686_msvc",
  "windows_x86_64_gnu",
  "windows_x86_64_gnullvm",
@@ -694,45 +741,51 @@ dependencies = [
 
 [[package]]
 name = "windows_aarch64_gnullvm"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cb7764e35d4db8a7921e09562a0304bf2f93e0a51bfccee0bd0bb0b666b015ea"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
 
 [[package]]
 name = "windows_aarch64_msvc"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbaa0368d4f1d2aaefc55b6fcfee13f41544ddf36801e793edbbfd7d7df075ef"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
 
 [[package]]
 name = "windows_i686_gnu"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a28637cb1fa3560a16915793afb20081aba2c92ee8af57b4d5f28e4b3e7df313"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
 
 [[package]]
 name = "windows_i686_msvc"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffe5e8e31046ce6230cc7215707b816e339ff4d4d67c65dffa206fd0f7aa7b9a"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
 
 [[package]]
 name = "windows_x86_64_gnu"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d6fa32db2bc4a2f5abeacf2b69f7992cd09dca97498da74a151a3132c26befd"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
 
 [[package]]
 name = "windows_x86_64_gnullvm"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a657e1e9d3f514745a572a6846d3c7aa7dbe1658c056ed9c3344c4109a6949e"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
 
 [[package]]
 name = "windows_x86_64_msvc"
-version = "0.52.0"
+version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dff9641d1cd4be8d1a070daf9e3773c5f67e78b4d9d42263020c057706765c04"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
 [[package]]
 name = "xattr"
diff --git a/src/bootstrap/Cargo.toml b/src/bootstrap/Cargo.toml
index f723407c3ce..84262c115b1 100644
--- a/src/bootstrap/Cargo.toml
+++ b/src/bootstrap/Cargo.toml
@@ -63,7 +63,7 @@ walkdir = "2.4"
 xz2 = "0.1"
 
 # Dependencies needed by the build-metrics feature
-sysinfo = { version = "0.30", default-features = false, optional = true }
+sysinfo = { version = "0.31.2", default-features = false, optional = true, features = ["system"] }
 
 [target.'cfg(windows)'.dependencies.junction]
 version = "1.0.0"
diff --git a/src/bootstrap/src/core/build_steps/check.rs b/src/bootstrap/src/core/build_steps/check.rs
index 8b71300cf85..7f7faf077d0 100644
--- a/src/bootstrap/src/core/build_steps/check.rs
+++ b/src/bootstrap/src/core/build_steps/check.rs
@@ -31,10 +31,6 @@ pub struct Std {
 }
 
 impl Std {
-    pub fn new(target: TargetSelection) -> Self {
-        Self::new_with_build_kind(target, None)
-    }
-
     pub fn new_with_build_kind(target: TargetSelection, kind: Option<Kind>) -> Self {
         Self { target, crates: vec![], override_build_kind: kind }
     }
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 1343e257efe..776e2c5cb17 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -512,6 +512,11 @@ impl TargetSelection {
     pub fn is_windows(&self) -> bool {
         self.contains("windows")
     }
+
+    /// Path to the file defining the custom target, if any.
+    pub fn filepath(&self) -> Option<&Path> {
+        self.file.as_ref().map(Path::new)
+    }
 }
 
 impl fmt::Display for TargetSelection {
diff --git a/src/bootstrap/src/core/sanity.rs b/src/bootstrap/src/core/sanity.rs
index 45f4090ef22..c42d4c56c38 100644
--- a/src/bootstrap/src/core/sanity.rs
+++ b/src/bootstrap/src/core/sanity.rs
@@ -260,7 +260,9 @@ than building it.
 
             if !has_target {
                 // This might also be a custom target, so check the target file that could have been specified by the user.
-                if let Some(custom_target_path) = env::var_os("RUST_TARGET_PATH") {
+                if target.filepath().is_some_and(|p| p.exists()) {
+                    has_target = true;
+                } else if let Some(custom_target_path) = env::var_os("RUST_TARGET_PATH") {
                     let mut target_filename = OsString::from(&target_str);
                     // Target filename ends with `.json`.
                     target_filename.push(".json");
@@ -275,8 +277,12 @@ than building it.
 
             if !has_target {
                 panic!(
-                    "No such target exists in the target list,
-                specify a correct location of the JSON specification file for custom targets!"
+                    "No such target exists in the target list,\n\
+                     make sure to correctly specify the location \
+                     of the JSON specification file \
+                     for custom targets!\n\
+                     Use BOOTSTRAP_SKIP_TARGET_SANITY=1 to \
+                     bypass this check."
                 );
             }
         }
diff --git a/src/bootstrap/src/utils/metrics.rs b/src/bootstrap/src/utils/metrics.rs
index bd18eb35c1f..e9acb93363e 100644
--- a/src/bootstrap/src/utils/metrics.rs
+++ b/src/bootstrap/src/utils/metrics.rs
@@ -13,7 +13,7 @@ use build_helper::metrics::{
     JsonInvocation, JsonInvocationSystemStats, JsonNode, JsonRoot, JsonStepSystemStats, Test,
     TestOutcome, TestSuite, TestSuiteMetadata,
 };
-use sysinfo::System;
+use sysinfo::{CpuRefreshKind, RefreshKind, System};
 
 use crate::core::builder::{Builder, Step};
 use crate::utils::helpers::t;
@@ -55,7 +55,9 @@ impl BuildMetrics {
             finished_steps: Vec::new(),
             running_steps: Vec::new(),
 
-            system_info: System::new(),
+            system_info: System::new_with_specifics(
+                RefreshKind::new().with_cpu(CpuRefreshKind::everything()),
+            ),
             timer_start: None,
             invocation_timer_start: Instant::now(),
             invocation_start: SystemTime::now(),
@@ -77,7 +79,7 @@ impl BuildMetrics {
             self.collect_stats(&mut *state);
         }
 
-        state.system_info.refresh_cpu();
+        state.system_info.refresh_cpu_usage();
         state.timer_start = Some(Instant::now());
 
         state.running_steps.push(StepMetrics {
@@ -110,7 +112,7 @@ impl BuildMetrics {
             state.running_steps.last_mut().unwrap().children.push(step);
 
             // Start collecting again for the parent step.
-            state.system_info.refresh_cpu();
+            state.system_info.refresh_cpu_usage();
             state.timer_start = Some(Instant::now());
         }
     }
@@ -148,7 +150,7 @@ impl BuildMetrics {
         let elapsed = state.timer_start.unwrap().elapsed();
         step.duration_excluding_children_sec += elapsed;
 
-        state.system_info.refresh_cpu();
+        state.system_info.refresh_cpu_usage();
         let cpu = state.system_info.cpus().iter().map(|p| p.cpu_usage()).sum::<f32>();
         step.cpu_usage_time_sec += cpu as f64 / 100.0 * elapsed.as_secs_f64();
     }
@@ -159,8 +161,9 @@ impl BuildMetrics {
 
         let dest = build.out.join("metrics.json");
 
-        let mut system = System::new();
-        system.refresh_cpu();
+        let mut system =
+            System::new_with_specifics(RefreshKind::new().with_cpu(CpuRefreshKind::everything()));
+        system.refresh_cpu_usage();
         system.refresh_memory();
 
         let system_stats = JsonInvocationSystemStats {
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 6961261d712..9617f0d9a1f 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -332,7 +332,6 @@ struct AllTypes {
     macros: FxHashSet<ItemEntry>,
     functions: FxHashSet<ItemEntry>,
     type_aliases: FxHashSet<ItemEntry>,
-    opaque_tys: FxHashSet<ItemEntry>,
     statics: FxHashSet<ItemEntry>,
     constants: FxHashSet<ItemEntry>,
     attribute_macros: FxHashSet<ItemEntry>,
@@ -352,7 +351,6 @@ impl AllTypes {
             macros: new_set(100),
             functions: new_set(100),
             type_aliases: new_set(100),
-            opaque_tys: new_set(100),
             statics: new_set(100),
             constants: new_set(100),
             attribute_macros: new_set(100),
@@ -415,9 +413,6 @@ impl AllTypes {
         if !self.type_aliases.is_empty() {
             sections.insert(ItemSection::TypeAliases);
         }
-        if !self.opaque_tys.is_empty() {
-            sections.insert(ItemSection::OpaqueTypes);
-        }
         if !self.statics.is_empty() {
             sections.insert(ItemSection::Statics);
         }
@@ -471,7 +466,6 @@ impl AllTypes {
         print_entries(f, &self.functions, ItemSection::Functions);
         print_entries(f, &self.type_aliases, ItemSection::TypeAliases);
         print_entries(f, &self.trait_aliases, ItemSection::TraitAliases);
-        print_entries(f, &self.opaque_tys, ItemSection::OpaqueTypes);
         print_entries(f, &self.statics, ItemSection::Statics);
         print_entries(f, &self.constants, ItemSection::Constants);
     }
@@ -2174,7 +2168,6 @@ pub(crate) enum ItemSection {
     AssociatedConstants,
     ForeignTypes,
     Keywords,
-    OpaqueTypes,
     AttributeMacros,
     DeriveMacros,
     TraitAliases,
@@ -2207,7 +2200,6 @@ impl ItemSection {
             AssociatedConstants,
             ForeignTypes,
             Keywords,
-            OpaqueTypes,
             AttributeMacros,
             DeriveMacros,
             TraitAliases,
@@ -2237,7 +2229,6 @@ impl ItemSection {
             Self::AssociatedConstants => "associated-consts",
             Self::ForeignTypes => "foreign-types",
             Self::Keywords => "keywords",
-            Self::OpaqueTypes => "opaque-types",
             Self::AttributeMacros => "attributes",
             Self::DeriveMacros => "derives",
             Self::TraitAliases => "trait-aliases",
@@ -2267,7 +2258,6 @@ impl ItemSection {
             Self::AssociatedConstants => "Associated Constants",
             Self::ForeignTypes => "Foreign Types",
             Self::Keywords => "Keywords",
-            Self::OpaqueTypes => "Opaque Types",
             Self::AttributeMacros => "Attribute Macros",
             Self::DeriveMacros => "Derive Macros",
             Self::TraitAliases => "Trait Aliases",
diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index e0ea234f9e7..67731f35496 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -568,7 +568,6 @@ function preLoadCss(cssUrl) {
             //block("associatedconstant", "associated-consts", "Associated Constants");
             block("foreigntype", "foreign-types", "Foreign Types");
             block("keyword", "keywords", "Keywords");
-            block("opaque", "opaque-types", "Opaque Types");
             block("attr", "attributes", "Attribute Macros");
             block("derive", "derives", "Derive Macros");
             block("traitalias", "trait-aliases", "Trait Aliases");
@@ -1115,8 +1114,7 @@ function preLoadCss(cssUrl) {
         wrapper.style.left = 0;
         wrapper.style.right = "auto";
         wrapper.style.visibility = "hidden";
-        const body = document.getElementsByTagName("body")[0];
-        body.appendChild(wrapper);
+        document.body.appendChild(wrapper);
         const wrapperPos = wrapper.getBoundingClientRect();
         // offset so that the arrow points at the center of the "(i)"
         const finalPos = pos.left + window.scrollX - wrapperPos.width + 24;
@@ -1235,8 +1233,7 @@ function preLoadCss(cssUrl) {
                 }
                 window.CURRENT_TOOLTIP_ELEMENT.TOOLTIP_BASE.TOOLTIP_FORCE_VISIBLE = false;
             }
-            const body = document.getElementsByTagName("body")[0];
-            body.removeChild(window.CURRENT_TOOLTIP_ELEMENT);
+            document.body.removeChild(window.CURRENT_TOOLTIP_ELEMENT);
             clearTooltipHoverTimeout(window.CURRENT_TOOLTIP_ELEMENT);
             window.CURRENT_TOOLTIP_ELEMENT = null;
         }
@@ -1833,7 +1830,7 @@ href="https://doc.rust-lang.org/${channel}/rustdoc/read-documentation/search.htm
         let elem = event.target;
         while (!hasClass(elem, "example-wrap")) {
             elem = elem.parentElement;
-            if (elem.tagName === "body" || hasClass(elem, "docblock")) {
+            if (elem === document.body || hasClass(elem, "docblock")) {
                 return null;
             }
         }
diff --git a/src/tools/cargo b/src/tools/cargo
index 257b72b8adf..fa646583675 160000
--- a/src/tools/cargo
+++ b/src/tools/cargo
@@ -1 +1 @@
-Subproject commit 257b72b8adfb1f2aa9916cefca67285c21666276
+Subproject commit fa646583675d7c140482bd906145c71b7fb4fc2b
diff --git a/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs b/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
index e4e7f7d06e7..080efe983c2 100644
--- a/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
+++ b/src/tools/clippy/clippy_lints/src/unnecessary_wraps.rs
@@ -145,7 +145,9 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
                 (
                     "this function's return value is unnecessary".to_string(),
                     "remove the return type...".to_string(),
-                    snippet(cx, fn_decl.output.span(), "..").to_string(),
+                    // FIXME: we should instead get the span including the `->` and suggest an
+                    // empty string for this case.
+                    "()".to_string(),
                     "...and then remove returned values",
                 )
             } else {
diff --git a/src/tools/clippy/tests/ui/unnecessary_literal_unwrap.stderr b/src/tools/clippy/tests/ui/unnecessary_literal_unwrap.stderr
index 15708090361..37ee9195fce 100644
--- a/src/tools/clippy/tests/ui/unnecessary_literal_unwrap.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_literal_unwrap.stderr
@@ -63,7 +63,7 @@ LL |     let _val = None::<()>.expect("this always happens");
 help: remove the `None` and `expect()`
    |
 LL |     let _val = panic!("this always happens");
-   |                ~~~~~~~                     ~
+   |                ~~~~~~~
 
 error: used `unwrap_or_default()` on `None` value
   --> tests/ui/unnecessary_literal_unwrap.rs:22:24
@@ -134,7 +134,7 @@ LL |     None::<()>.expect("this always happens");
 help: remove the `None` and `expect()`
    |
 LL |     panic!("this always happens");
-   |     ~~~~~~~                     ~
+   |     ~~~~~~~
 
 error: used `unwrap_or_default()` on `None` value
   --> tests/ui/unnecessary_literal_unwrap.rs:30:5
diff --git a/src/tools/clippy/tests/ui/unnecessary_wraps.stderr b/src/tools/clippy/tests/ui/unnecessary_wraps.stderr
index a55a23d449f..59986d895b3 100644
--- a/src/tools/clippy/tests/ui/unnecessary_wraps.stderr
+++ b/src/tools/clippy/tests/ui/unnecessary_wraps.stderr
@@ -118,8 +118,8 @@ LL | | }
    |
 help: remove the return type...
    |
-LL | fn issue_6640_1(a: bool, b: bool) -> Option<()> {
-   |                                      ~~~~~~~~~~
+LL | fn issue_6640_1(a: bool, b: bool) -> () {
+   |                                      ~~
 help: ...and then remove returned values
    |
 LL ~         return ;
@@ -145,8 +145,8 @@ LL | | }
    |
 help: remove the return type...
    |
-LL | fn issue_6640_2(a: bool, b: bool) -> Result<(), i32> {
-   |                                      ~~~~~~~~~~~~~~~
+LL | fn issue_6640_2(a: bool, b: bool) -> () {
+   |                                      ~~
 help: ...and then remove returned values
    |
 LL ~         return ;
diff --git a/src/tools/compiletest/src/command-list.rs b/src/tools/compiletest/src/command-list.rs
index 288f90ea123..0706f3bee05 100644
--- a/src/tools/compiletest/src/command-list.rs
+++ b/src/tools/compiletest/src/command-list.rs
@@ -18,6 +18,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "check-test-line-numbers-match",
     "compare-output-lines-by-subset",
     "compile-flags",
+    "doc-flags",
     "dont-check-compiler-stderr",
     "dont-check-compiler-stdout",
     "dont-check-failure-status",
@@ -226,6 +227,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "should-ice",
     "stderr-per-bitwidth",
     "test-mir-pass",
+    "unique-doc-out-dir",
     "unset-exec-env",
     "unset-rustc-env",
     // Used by the tidy check `unknown_revision`.
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index cde3e3295c6..1fc24301c85 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -95,6 +95,8 @@ pub struct TestProps {
     pub compile_flags: Vec<String>,
     // Extra flags to pass when the compiled code is run (such as --bench)
     pub run_flags: Vec<String>,
+    /// Extra flags to pass to rustdoc but not the compiler.
+    pub doc_flags: Vec<String>,
     // If present, the name of a file that this test should match when
     // pretty-printed
     pub pp_exact: Option<PathBuf>,
@@ -122,6 +124,9 @@ pub struct TestProps {
     pub unset_exec_env: Vec<String>,
     // Build documentation for all specified aux-builds as well
     pub build_aux_docs: bool,
+    /// Build the documentation for each crate in a unique output directory.
+    /// Uses <root output directory>/docs/<test name>/doc
+    pub unique_doc_out_dir: bool,
     // Flag to force a crate to be built with the host architecture
     pub force_host: bool,
     // Check stdout for error-pattern output as well as stderr
@@ -220,8 +225,10 @@ mod directives {
     pub const REGEX_ERROR_PATTERN: &'static str = "regex-error-pattern";
     pub const COMPILE_FLAGS: &'static str = "compile-flags";
     pub const RUN_FLAGS: &'static str = "run-flags";
+    pub const DOC_FLAGS: &'static str = "doc-flags";
     pub const SHOULD_ICE: &'static str = "should-ice";
     pub const BUILD_AUX_DOCS: &'static str = "build-aux-docs";
+    pub const UNIQUE_DOC_OUT_DIR: &'static str = "unique-doc-out-dir";
     pub const FORCE_HOST: &'static str = "force-host";
     pub const CHECK_STDOUT: &'static str = "check-stdout";
     pub const CHECK_RUN_RESULTS: &'static str = "check-run-results";
@@ -267,6 +274,7 @@ impl TestProps {
             regex_error_patterns: vec![],
             compile_flags: vec![],
             run_flags: vec![],
+            doc_flags: vec![],
             pp_exact: None,
             aux_builds: vec![],
             aux_bins: vec![],
@@ -281,6 +289,7 @@ impl TestProps {
             exec_env: vec![],
             unset_exec_env: vec![],
             build_aux_docs: false,
+            unique_doc_out_dir: false,
             force_host: false,
             check_stdout: false,
             check_run_results: false,
@@ -378,6 +387,8 @@ impl TestProps {
                         |r| r,
                     );
 
+                    config.push_name_value_directive(ln, DOC_FLAGS, &mut self.doc_flags, |r| r);
+
                     fn split_flags(flags: &str) -> Vec<String> {
                         // Individual flags can be single-quoted to preserve spaces; see
                         // <https://github.com/rust-lang/rust/pull/115948/commits/957c5db6>.
@@ -415,6 +426,8 @@ impl TestProps {
 
                     config.set_name_directive(ln, SHOULD_ICE, &mut self.should_ice);
                     config.set_name_directive(ln, BUILD_AUX_DOCS, &mut self.build_aux_docs);
+                    config.set_name_directive(ln, UNIQUE_DOC_OUT_DIR, &mut self.unique_doc_out_dir);
+
                     config.set_name_directive(ln, FORCE_HOST, &mut self.force_host);
                     config.set_name_directive(ln, CHECK_STDOUT, &mut self.check_stdout);
                     config.set_name_directive(ln, CHECK_RUN_RESULTS, &mut self.check_run_results);
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 1f15605d8be..b1b6d6fc8eb 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1,5 +1,6 @@
 // ignore-tidy-filelength
 
+use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
 use std::ffi::{OsStr, OsString};
 use std::fs::{self, create_dir_all, File, OpenOptions};
@@ -723,7 +724,7 @@ impl<'test> TestCx<'test> {
         self.maybe_add_external_args(&mut rustc, &self.config.target_rustcflags);
         rustc.args(&self.props.compile_flags);
 
-        self.compose_and_run_compiler(rustc, Some(src))
+        self.compose_and_run_compiler(rustc, Some(src), self.testpaths)
     }
 
     fn run_debuginfo_test(&self) {
@@ -1579,13 +1580,15 @@ impl<'test> TestCx<'test> {
             passes,
         );
 
-        self.compose_and_run_compiler(rustc, None)
+        self.compose_and_run_compiler(rustc, None, self.testpaths)
     }
 
-    fn document(&self, out_dir: &Path) -> ProcRes {
+    /// `root_out_dir` and `root_testpaths` refer to the parameters of the actual test being run.
+    /// Auxiliaries, no matter how deep, have the same root_out_dir and root_testpaths.
+    fn document(&self, root_out_dir: &Path, root_testpaths: &TestPaths) -> ProcRes {
         if self.props.build_aux_docs {
             for rel_ab in &self.props.aux_builds {
-                let aux_testpaths = self.compute_aux_test_paths(&self.testpaths, rel_ab);
+                let aux_testpaths = self.compute_aux_test_paths(root_testpaths, rel_ab);
                 let aux_props =
                     self.props.from_aux_file(&aux_testpaths.file, self.revision, self.config);
                 let aux_cx = TestCx {
@@ -1596,7 +1599,9 @@ impl<'test> TestCx<'test> {
                 };
                 // Create the directory for the stdout/stderr files.
                 create_dir_all(aux_cx.output_base_dir()).unwrap();
-                let auxres = aux_cx.document(out_dir);
+                // use root_testpaths here, because aux-builds should have the
+                // same --out-dir and auxiliary directory.
+                let auxres = aux_cx.document(&root_out_dir, root_testpaths);
                 if !auxres.status.success() {
                     return auxres;
                 }
@@ -1606,21 +1611,40 @@ impl<'test> TestCx<'test> {
         let aux_dir = self.aux_output_dir_name();
 
         let rustdoc_path = self.config.rustdoc_path.as_ref().expect("--rustdoc-path not passed");
-        let mut rustdoc = Command::new(rustdoc_path);
 
+        // actual --out-dir given to the auxiliary or test, as opposed to the root out dir for the entire
+        // test
+        let out_dir: Cow<'_, Path> = if self.props.unique_doc_out_dir {
+            let file_name = self.testpaths.file.file_stem().expect("file name should not be empty");
+            let out_dir = PathBuf::from_iter([
+                root_out_dir,
+                Path::new("docs"),
+                Path::new(file_name),
+                Path::new("doc"),
+            ]);
+            create_dir_all(&out_dir).unwrap();
+            Cow::Owned(out_dir)
+        } else {
+            Cow::Borrowed(root_out_dir)
+        };
+
+        let mut rustdoc = Command::new(rustdoc_path);
+        let current_dir = output_base_dir(self.config, root_testpaths, self.safe_revision());
+        rustdoc.current_dir(current_dir);
         rustdoc
             .arg("-L")
             .arg(self.config.run_lib_path.to_str().unwrap())
             .arg("-L")
             .arg(aux_dir)
             .arg("-o")
-            .arg(out_dir)
+            .arg(out_dir.as_ref())
             .arg("--deny")
             .arg("warnings")
             .arg(&self.testpaths.file)
             .arg("-A")
             .arg("internal_features")
-            .args(&self.props.compile_flags);
+            .args(&self.props.compile_flags)
+            .args(&self.props.doc_flags);
 
         if self.config.mode == RustdocJson {
             rustdoc.arg("--output-format").arg("json").arg("-Zunstable-options");
@@ -1630,7 +1654,7 @@ impl<'test> TestCx<'test> {
             rustdoc.arg(format!("-Clinker={}", linker));
         }
 
-        self.compose_and_run_compiler(rustdoc, None)
+        self.compose_and_run_compiler(rustdoc, None, root_testpaths)
     }
 
     fn exec_compiled_test(&self) -> ProcRes {
@@ -1828,9 +1852,16 @@ impl<'test> TestCx<'test> {
         }
     }
 
-    fn compose_and_run_compiler(&self, mut rustc: Command, input: Option<String>) -> ProcRes {
+    /// `root_testpaths` refers to the path of the original test.
+    /// the auxiliary and the test with an aux-build have the same `root_testpaths`.
+    fn compose_and_run_compiler(
+        &self,
+        mut rustc: Command,
+        input: Option<String>,
+        root_testpaths: &TestPaths,
+    ) -> ProcRes {
         let aux_dir = self.aux_output_dir();
-        self.build_all_auxiliary(&self.testpaths, &aux_dir, &mut rustc);
+        self.build_all_auxiliary(root_testpaths, &aux_dir, &mut rustc);
 
         rustc.envs(self.props.rustc_env.clone());
         self.props.unset_rustc_env.iter().fold(&mut rustc, Command::env_remove);
@@ -2545,7 +2576,7 @@ impl<'test> TestCx<'test> {
             Vec::new(),
         );
 
-        let proc_res = self.compose_and_run_compiler(rustc, None);
+        let proc_res = self.compose_and_run_compiler(rustc, None, self.testpaths);
         let output_path = self.get_filecheck_file("ll");
         (proc_res, output_path)
     }
@@ -2581,7 +2612,7 @@ impl<'test> TestCx<'test> {
             Vec::new(),
         );
 
-        let proc_res = self.compose_and_run_compiler(rustc, None);
+        let proc_res = self.compose_and_run_compiler(rustc, None, self.testpaths);
         let output_path = self.get_filecheck_file("s");
         (proc_res, output_path)
     }
@@ -2664,7 +2695,7 @@ impl<'test> TestCx<'test> {
         let out_dir = self.output_base_dir();
         remove_and_create_dir_all(&out_dir);
 
-        let proc_res = self.document(&out_dir);
+        let proc_res = self.document(&out_dir, &self.testpaths);
         if !proc_res.status.success() {
             self.fatal_proc_rec("rustdoc failed!", &proc_res);
         }
@@ -2723,7 +2754,7 @@ impl<'test> TestCx<'test> {
         let aux_dir = new_rustdoc.aux_output_dir();
         new_rustdoc.build_all_auxiliary(&new_rustdoc.testpaths, &aux_dir, &mut rustc);
 
-        let proc_res = new_rustdoc.document(&compare_dir);
+        let proc_res = new_rustdoc.document(&compare_dir, &new_rustdoc.testpaths);
         if !proc_res.status.success() {
             eprintln!("failed to run nightly rustdoc");
             return;
@@ -2847,7 +2878,7 @@ impl<'test> TestCx<'test> {
         let out_dir = self.output_base_dir();
         remove_and_create_dir_all(&out_dir);
 
-        let proc_res = self.document(&out_dir);
+        let proc_res = self.document(&out_dir, &self.testpaths);
         if !proc_res.status.success() {
             self.fatal_proc_rec("rustdoc failed!", &proc_res);
         }
@@ -2923,31 +2954,24 @@ impl<'test> TestCx<'test> {
     fn check_rustdoc_test_option(&self, res: ProcRes) {
         let mut other_files = Vec::new();
         let mut files: HashMap<String, Vec<usize>> = HashMap::new();
-        let cwd = env::current_dir().unwrap();
-        files.insert(
-            self.testpaths
-                .file
-                .strip_prefix(&cwd)
-                .unwrap_or(&self.testpaths.file)
-                .to_str()
-                .unwrap()
-                .replace('\\', "/"),
-            self.get_lines(&self.testpaths.file, Some(&mut other_files)),
-        );
+        let normalized = fs::canonicalize(&self.testpaths.file).expect("failed to canonicalize");
+        let normalized = normalized.to_str().unwrap().replace('\\', "/");
+        files.insert(normalized, self.get_lines(&self.testpaths.file, Some(&mut other_files)));
         for other_file in other_files {
             let mut path = self.testpaths.file.clone();
             path.set_file_name(&format!("{}.rs", other_file));
-            files.insert(
-                path.strip_prefix(&cwd).unwrap_or(&path).to_str().unwrap().replace('\\', "/"),
-                self.get_lines(&path, None),
-            );
+            let path = fs::canonicalize(path).expect("failed to canonicalize");
+            let normalized = path.to_str().unwrap().replace('\\', "/");
+            files.insert(normalized, self.get_lines(&path, None));
         }
 
         let mut tested = 0;
         for _ in res.stdout.split('\n').filter(|s| s.starts_with("test ")).inspect(|s| {
             if let Some((left, right)) = s.split_once(" - ") {
                 let path = left.rsplit("test ").next().unwrap();
-                if let Some(ref mut v) = files.get_mut(&path.replace('\\', "/")) {
+                let path = fs::canonicalize(&path).expect("failed to canonicalize");
+                let path = path.to_str().unwrap().replace('\\', "/");
+                if let Some(ref mut v) = files.get_mut(&path) {
                     tested += 1;
                     let mut iter = right.split("(line ");
                     iter.next();
@@ -3779,7 +3803,7 @@ impl<'test> TestCx<'test> {
         if let Some(nodejs) = &self.config.nodejs {
             let out_dir = self.output_base_dir();
 
-            self.document(&out_dir);
+            self.document(&out_dir, &self.testpaths);
 
             let root = self.config.find_rust_src_root().unwrap();
             let file_stem =
@@ -4095,7 +4119,7 @@ impl<'test> TestCx<'test> {
                 rustc.arg(crate_name);
             }
 
-            let res = self.compose_and_run_compiler(rustc, None);
+            let res = self.compose_and_run_compiler(rustc, None, self.testpaths);
             if !res.status.success() {
                 self.fatal_proc_rec("failed to compile fixed code", &res);
             }
diff --git a/src/tools/compiletest/src/runtest/coverage.rs b/src/tools/compiletest/src/runtest/coverage.rs
index 6ee147da5a9..05191a15980 100644
--- a/src/tools/compiletest/src/runtest/coverage.rs
+++ b/src/tools/compiletest/src/runtest/coverage.rs
@@ -191,7 +191,7 @@ impl<'test> TestCx<'test> {
 
         rustdoc_cmd.arg(&self.testpaths.file);
 
-        let proc_res = self.compose_and_run_compiler(rustdoc_cmd, None);
+        let proc_res = self.compose_and_run_compiler(rustdoc_cmd, None, self.testpaths);
         if !proc_res.status.success() {
             self.fatal_proc_rec("rustdoc --test failed!", &proc_res)
         }
diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
index 950d2baabe9..f03fe70aa21 100644
--- a/src/tools/miri/rust-version
+++ b/src/tools/miri/rust-version
@@ -1 +1 @@
-05e692ae025fd4650c601e1e7ab51bdc5e19c35b
+1df0458781d6fd753a68c4cdc4de5313b1635dbd
diff --git a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs
deleted file mode 100644
index c14f86147db..00000000000
--- a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-#![feature(intrinsics)]
-
-extern "rust-intrinsic" {
-    fn raw_eq<T>(a: &T, b: &T) -> bool;
-}
-
-fn main() {
-    let x = &0;
-    unsafe { raw_eq(&x, &x) }; //~ERROR: `raw_eq` on bytes with provenance
-}
diff --git a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr b/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr
deleted file mode 100644
index 83f81fa726e..00000000000
--- a/src/tools/miri/tests/fail/intrinsics/raw_eq_on_ptr.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error: Undefined Behavior: `raw_eq` on bytes with provenance
-  --> $DIR/raw_eq_on_ptr.rs:LL:CC
-   |
-LL |     unsafe { raw_eq(&x, &x) };
-   |              ^^^^^^^^^^^^^^ `raw_eq` on bytes with provenance
-   |
-   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
-   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
-   = note: BACKTRACE:
-   = note: inside `main` at $DIR/raw_eq_on_ptr.rs:LL:CC
-
-note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
-
-error: aborting due to 1 previous error
-
diff --git a/src/tools/opt-dist/Cargo.toml b/src/tools/opt-dist/Cargo.toml
index 88e8640d56a..d34f8ad0520 100644
--- a/src/tools/opt-dist/Cargo.toml
+++ b/src/tools/opt-dist/Cargo.toml
@@ -10,7 +10,7 @@ log = "0.4"
 anyhow = { version = "1", features = ["backtrace"] }
 humantime = "2"
 humansize = "2"
-sysinfo = { version = "0.30", default-features = false }
+sysinfo = { version = "0.31.2", default-features = false, features = ["disk"] }
 fs_extra = "1"
 camino = "1"
 tar = "0.4"
diff --git a/src/tools/run-make-support/src/external_deps/c_build.rs b/src/tools/run-make-support/src/external_deps/c_build.rs
index 86c9c081831..15e02d04393 100644
--- a/src/tools/run-make-support/src/external_deps/c_build.rs
+++ b/src/tools/run-make-support/src/external_deps/c_build.rs
@@ -2,7 +2,7 @@ use std::path::PathBuf;
 
 use super::cygpath::get_windows_path;
 use crate::artifact_names::{dynamic_lib_name, static_lib_name};
-use crate::external_deps::cc::cc;
+use crate::external_deps::cc::{cc, cxx};
 use crate::external_deps::llvm::llvm_ar;
 use crate::path_helpers::path;
 use crate::targets::{is_darwin, is_msvc, is_windows};
@@ -10,6 +10,7 @@ use crate::targets::{is_darwin, is_msvc, is_windows};
 // FIXME(Oneirical): These native build functions should take a Path-based generic.
 
 /// Builds a static lib (`.lib` on Windows MSVC and `.a` for the rest) with the given name.
+/// Built from a C file.
 #[track_caller]
 pub fn build_native_static_lib(lib_name: &str) -> PathBuf {
     let obj_file = if is_msvc() { format!("{lib_name}") } else { format!("{lib_name}.o") };
@@ -58,3 +59,24 @@ pub fn build_native_dynamic_lib(lib_name: &str) -> PathBuf {
     }
     path(lib_path)
 }
+
+/// Builds a static lib (`.lib` on Windows MSVC and `.a` for the rest) with the given name.
+/// Built from a C++ file.
+#[track_caller]
+pub fn build_native_static_lib_cxx(lib_name: &str) -> PathBuf {
+    let obj_file = if is_msvc() { format!("{lib_name}") } else { format!("{lib_name}.o") };
+    let src = format!("{lib_name}.cpp");
+    let lib_path = static_lib_name(lib_name);
+    if is_msvc() {
+        cxx().arg("-EHs").arg("-c").out_exe(&obj_file).input(src).run();
+    } else {
+        cxx().arg("-c").out_exe(&obj_file).input(src).run();
+    };
+    let obj_file = if is_msvc() {
+        PathBuf::from(format!("{lib_name}.obj"))
+    } else {
+        PathBuf::from(format!("{lib_name}.o"))
+    };
+    llvm_ar().obj_to_ar().output_input(&lib_path, &obj_file).run();
+    path(lib_path)
+}
diff --git a/src/tools/run-make-support/src/external_deps/clang.rs b/src/tools/run-make-support/src/external_deps/clang.rs
index 2b0712541cd..2d110c6825e 100644
--- a/src/tools/run-make-support/src/external_deps/clang.rs
+++ b/src/tools/run-make-support/src/external_deps/clang.rs
@@ -1,7 +1,7 @@
 use std::path::Path;
 
 use crate::command::Command;
-use crate::{bin_name, env_var};
+use crate::{bin_name, cwd, env_var};
 
 /// Construct a new `clang` invocation. `clang` is not always available for all targets.
 #[track_caller]
@@ -23,7 +23,8 @@ impl Clang {
     #[track_caller]
     pub fn new() -> Self {
         let clang = env_var("CLANG");
-        let cmd = Command::new(clang);
+        let mut cmd = Command::new(clang);
+        cmd.arg("-L").arg(cwd());
         Self { cmd }
     }
 
diff --git a/src/tools/run-make-support/src/external_deps/llvm.rs b/src/tools/run-make-support/src/external_deps/llvm.rs
index 259bb615946..56021cec269 100644
--- a/src/tools/run-make-support/src/external_deps/llvm.rs
+++ b/src/tools/run-make-support/src/external_deps/llvm.rs
@@ -42,6 +42,12 @@ pub fn llvm_nm() -> LlvmNm {
     LlvmNm::new()
 }
 
+/// Construct a new `llvm-bcanalyzer` invocation. This assumes that `llvm-bcanalyzer` is available
+/// at `$LLVM_BIN_DIR/llvm-bcanalyzer`.
+pub fn llvm_bcanalyzer() -> LlvmBcanalyzer {
+    LlvmBcanalyzer::new()
+}
+
 /// A `llvm-readobj` invocation builder.
 #[derive(Debug)]
 #[must_use]
@@ -84,12 +90,20 @@ pub struct LlvmNm {
     cmd: Command,
 }
 
+/// A `llvm-bcanalyzer` invocation builder.
+#[derive(Debug)]
+#[must_use]
+pub struct LlvmBcanalyzer {
+    cmd: Command,
+}
+
 crate::macros::impl_common_helpers!(LlvmReadobj);
 crate::macros::impl_common_helpers!(LlvmProfdata);
 crate::macros::impl_common_helpers!(LlvmFilecheck);
 crate::macros::impl_common_helpers!(LlvmObjdump);
 crate::macros::impl_common_helpers!(LlvmAr);
 crate::macros::impl_common_helpers!(LlvmNm);
+crate::macros::impl_common_helpers!(LlvmBcanalyzer);
 
 /// Generate the path to the bin directory of LLVM.
 #[must_use]
@@ -232,6 +246,12 @@ impl LlvmObjdump {
         self.cmd.arg(path.as_ref());
         self
     }
+
+    /// Disassemble all executable sections found in the input files.
+    pub fn disassemble(&mut self) -> &mut Self {
+        self.cmd.arg("-d");
+        self
+    }
 }
 
 impl LlvmAr {
@@ -250,6 +270,12 @@ impl LlvmAr {
         self
     }
 
+    /// Extract archive members back to files.
+    pub fn extract(&mut self) -> &mut Self {
+        self.cmd.arg("x");
+        self
+    }
+
     /// Provide an output, then an input file. Bundled in one function, as llvm-ar has
     /// no "--output"-style flag.
     pub fn output_input(&mut self, out: impl AsRef<Path>, input: impl AsRef<Path>) -> &mut Self {
@@ -274,3 +300,19 @@ impl LlvmNm {
         self
     }
 }
+
+impl LlvmBcanalyzer {
+    /// Construct a new `llvm-bcanalyzer` invocation. This assumes that `llvm-bcanalyzer` is available
+    /// at `$LLVM_BIN_DIR/llvm-bcanalyzer`.
+    pub fn new() -> Self {
+        let llvm_bcanalyzer = llvm_bin_dir().join("llvm-bcanalyzer");
+        let cmd = Command::new(llvm_bcanalyzer);
+        Self { cmd }
+    }
+
+    /// Provide an input file.
+    pub fn input<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
+        self.cmd.arg(path.as_ref());
+        self
+    }
+}
diff --git a/src/tools/run-make-support/src/external_deps/rustc.rs b/src/tools/run-make-support/src/external_deps/rustc.rs
index 71d28dd9675..cece58d2956 100644
--- a/src/tools/run-make-support/src/external_deps/rustc.rs
+++ b/src/tools/run-make-support/src/external_deps/rustc.rs
@@ -5,6 +5,7 @@ use crate::command::Command;
 use crate::env::env_var;
 use crate::path_helpers::cwd;
 use crate::util::set_host_rpath;
+use crate::{is_darwin, is_msvc, is_windows, uname};
 
 /// Construct a new `rustc` invocation. This will automatically set the library
 /// search path as `-L cwd()`. Use [`bare_rustc`] to avoid this.
@@ -314,4 +315,62 @@ impl Rustc {
         self.cmd.arg(format!("-Clinker-flavor={linker_flavor}"));
         self
     }
+
+    /// `EXTRARSCXXFLAGS`
+    pub fn extra_rs_cxx_flags(&mut self) -> &mut Self {
+        // Adapted from tools.mk (trimmed):
+        //
+        // ```makefile
+        // ifdef IS_WINDOWS
+        //     ifdef IS_MSVC
+        //     else
+        //         EXTRARSCXXFLAGS := -lstatic:-bundle=stdc++
+        //     endif
+        // else
+        //     ifeq ($(UNAME),Darwin)
+        //         EXTRARSCXXFLAGS := -lc++
+        //     else
+        //         ifeq ($(UNAME),FreeBSD)
+        //         else
+        //             ifeq ($(UNAME),SunOS)
+        //             else
+        //                 ifeq ($(UNAME),OpenBSD)
+        //                 else
+        //                     EXTRARSCXXFLAGS := -lstdc++
+        //                 endif
+        //             endif
+        //         endif
+        //     endif
+        // endif
+        // ```
+        let flag = if is_windows() {
+            // So this is a bit hacky: we can't use the DLL version of libstdc++ because
+            // it pulls in the DLL version of libgcc, which means that we end up with 2
+            // instances of the DW2 unwinding implementation. This is a problem on
+            // i686-pc-windows-gnu because each module (DLL/EXE) needs to register its
+            // unwind information with the unwinding implementation, and libstdc++'s
+            // __cxa_throw won't see the unwinding info we registered with our statically
+            // linked libgcc.
+            //
+            // Now, simply statically linking libstdc++ would fix this problem, except
+            // that it is compiled with the expectation that pthreads is dynamically
+            // linked as a DLL and will fail to link with a statically linked libpthread.
+            //
+            // So we end up with the following hack: we link use static:-bundle to only
+            // link the parts of libstdc++ that we actually use, which doesn't include
+            // the dependency on the pthreads DLL.
+            if is_msvc() { None } else { Some("-lstatic:-bundle=stdc++") }
+        } else if is_darwin() {
+            Some("-lc++")
+        } else {
+            match &uname()[..] {
+                "FreeBSD" | "SunOS" | "OpenBSD" => None,
+                _ => Some("-lstdc++"),
+            }
+        };
+        if let Some(flag) = flag {
+            self.cmd.arg(flag);
+        }
+        self
+    }
 }
diff --git a/src/tools/run-make-support/src/lib.rs b/src/tools/run-make-support/src/lib.rs
index 9ccc37b25d7..63c4c4d8863 100644
--- a/src/tools/run-make-support/src/lib.rs
+++ b/src/tools/run-make-support/src/lib.rs
@@ -44,13 +44,13 @@ pub use wasmparser;
 pub use external_deps::{c_build, cc, clang, htmldocck, llvm, python, rustc, rustdoc};
 
 // These rely on external dependencies.
-pub use c_build::{build_native_dynamic_lib, build_native_static_lib};
 pub use cc::{cc, cxx, extra_c_flags, extra_cxx_flags, Cc};
+pub use c_build::{build_native_dynamic_lib, build_native_static_lib, build_native_static_lib_cxx};
 pub use clang::{clang, Clang};
 pub use htmldocck::htmldocck;
 pub use llvm::{
-    llvm_ar, llvm_filecheck, llvm_nm, llvm_objdump, llvm_profdata, llvm_readobj, LlvmAr,
-    LlvmFilecheck, LlvmNm, LlvmObjdump, LlvmProfdata, LlvmReadobj,
+    llvm_ar, llvm_bcanalyzer, llvm_filecheck, llvm_nm, llvm_objdump, llvm_profdata, llvm_readobj,
+    LlvmAr, LlvmBcanalyzer, LlvmFilecheck, LlvmNm, LlvmObjdump, LlvmProfdata, LlvmReadobj,
 };
 pub use python::python_command;
 pub use rustc::{aux_build, bare_rustc, rustc, Rustc};
diff --git a/src/tools/rustfmt/tests/source/cfg_if/detect/os/x86.rs b/src/tools/rustfmt/tests/source/cfg_if/detect/os/x86.rs
index 9257b8a4be6..b9adc67221a 100644
--- a/src/tools/rustfmt/tests/source/cfg_if/detect/os/x86.rs
+++ b/src/tools/rustfmt/tests/source/cfg_if/detect/os/x86.rs
@@ -34,15 +34,6 @@ pub fn check_for(x: Feature) -> bool {
 fn detect_features() -> cache::Initializer {
     let mut value = cache::Initializer::default();
 
-    // If the x86 CPU does not support the CPUID instruction then it is too
-    // old to support any of the currently-detectable features.
-    if !has_cpuid() {
-        return value;
-    }
-
-    // Calling `__cpuid`/`__cpuid_count` from here on is safe because the CPU
-    // has `cpuid` support.
-
     // 0. EAX = 0: Basic Information:
     // - EAX returns the "Highest Function Parameter", that is, the maximum
     // leaf value for subsequent calls of `cpuinfo` in range [0,
diff --git a/src/tools/rustfmt/tests/target/cfg_if/detect/os/x86.rs b/src/tools/rustfmt/tests/target/cfg_if/detect/os/x86.rs
index 2e228aa3745..944b51615f8 100644
--- a/src/tools/rustfmt/tests/target/cfg_if/detect/os/x86.rs
+++ b/src/tools/rustfmt/tests/target/cfg_if/detect/os/x86.rs
@@ -34,15 +34,6 @@ pub fn check_for(x: Feature) -> bool {
 fn detect_features() -> cache::Initializer {
     let mut value = cache::Initializer::default();
 
-    // If the x86 CPU does not support the CPUID instruction then it is too
-    // old to support any of the currently-detectable features.
-    if !has_cpuid() {
-        return value;
-    }
-
-    // Calling `__cpuid`/`__cpuid_count` from here on is safe because the CPU
-    // has `cpuid` support.
-
     // 0. EAX = 0: Basic Information:
     // - EAX returns the "Highest Function Parameter", that is, the maximum
     // leaf value for subsequent calls of `cpuinfo` in range [0,
diff --git a/src/tools/tidy/src/allowed_run_make_makefiles.txt b/src/tools/tidy/src/allowed_run_make_makefiles.txt
index d52ffe6e9f5..a04e239abb0 100644
--- a/src/tools/tidy/src/allowed_run_make_makefiles.txt
+++ b/src/tools/tidy/src/allowed_run_make_makefiles.txt
@@ -1,27 +1,19 @@
 run-make/branch-protection-check-IBT/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
 run-make/cdylib-dylib-linkage/Makefile
-run-make/cross-lang-lto-clang/Makefile
-run-make/cross-lang-lto-pgo-smoketest/Makefile
 run-make/cross-lang-lto-upstream-rlibs/Makefile
-run-make/cross-lang-lto/Makefile
 run-make/dep-info-doesnt-run-much/Makefile
 run-make/dep-info-spaces/Makefile
 run-make/dep-info/Makefile
 run-make/emit-to-stdout/Makefile
 run-make/extern-fn-reachable/Makefile
-run-make/foreign-double-unwind/Makefile
-run-make/foreign-exceptions/Makefile
 run-make/incr-add-rust-src-component/Makefile
-run-make/issue-36710/Makefile
 run-make/issue-84395-lto-embed-bitcode/Makefile
-run-make/issue-88756-default-output/Makefile
 run-make/jobserver-error/Makefile
 run-make/libs-through-symlinks/Makefile
 run-make/libtest-json/Makefile
 run-make/libtest-junit/Makefile
 run-make/libtest-thread-limit/Makefile
-run-make/link-cfg/Makefile
 run-make/long-linker-command-lines-cmd-exe/Makefile
 run-make/long-linker-command-lines/Makefile
 run-make/macos-deployment-target/Makefile
diff --git a/tests/codegen-units/item-collection/generic-impl.rs b/tests/codegen-units/item-collection/generic-impl.rs
index b4cd99272b1..23d09e0d8af 100644
--- a/tests/codegen-units/item-collection/generic-impl.rs
+++ b/tests/codegen-units/item-collection/generic-impl.rs
@@ -22,16 +22,16 @@ impl<T> Struct<T> {
     }
 }
 
-pub struct _LifeTimeOnly<'a> {
+pub struct LifeTimeOnly<'a> {
     _a: &'a u32,
 }
 
-impl<'a> _LifeTimeOnly<'a> {
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::foo
+impl<'a> LifeTimeOnly<'a> {
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::foo
     pub fn foo(&self) {}
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::bar
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::bar
     pub fn bar(&'a self) {}
-    //~ MONO_ITEM fn _LifeTimeOnly::<'_>::baz
+    //~ MONO_ITEM fn LifeTimeOnly::<'_>::baz
     pub fn baz<'b>(&'b self) {}
 
     pub fn non_instantiated<T>(&self) {}
diff --git a/tests/codegen-units/item-collection/overloaded-operators.rs b/tests/codegen-units/item-collection/overloaded-operators.rs
index e00e22dbab9..69b55695d3d 100644
--- a/tests/codegen-units/item-collection/overloaded-operators.rs
+++ b/tests/codegen-units/item-collection/overloaded-operators.rs
@@ -5,44 +5,44 @@
 
 use std::ops::{Add, Deref, Index, IndexMut};
 
-pub struct _Indexable {
+pub struct Indexable {
     data: [u8; 3],
 }
 
-impl Index<usize> for _Indexable {
+impl Index<usize> for Indexable {
     type Output = u8;
 
-    //~ MONO_ITEM fn <_Indexable as std::ops::Index<usize>>::index
+    //~ MONO_ITEM fn <Indexable as std::ops::Index<usize>>::index
     fn index(&self, index: usize) -> &Self::Output {
         if index >= 3 { &self.data[0] } else { &self.data[index] }
     }
 }
 
-impl IndexMut<usize> for _Indexable {
-    //~ MONO_ITEM fn <_Indexable as std::ops::IndexMut<usize>>::index_mut
+impl IndexMut<usize> for Indexable {
+    //~ MONO_ITEM fn <Indexable as std::ops::IndexMut<usize>>::index_mut
     fn index_mut(&mut self, index: usize) -> &mut Self::Output {
         if index >= 3 { &mut self.data[0] } else { &mut self.data[index] }
     }
 }
 
-//~ MONO_ITEM fn <_Equatable as std::cmp::PartialEq>::eq
-//~ MONO_ITEM fn <_Equatable as std::cmp::PartialEq>::ne
+//~ MONO_ITEM fn <Equatable as std::cmp::PartialEq>::eq
+//~ MONO_ITEM fn <Equatable as std::cmp::PartialEq>::ne
 #[derive(PartialEq)]
-pub struct _Equatable(u32);
+pub struct Equatable(u32);
 
-impl Add<u32> for _Equatable {
+impl Add<u32> for Equatable {
     type Output = u32;
 
-    //~ MONO_ITEM fn <_Equatable as std::ops::Add<u32>>::add
+    //~ MONO_ITEM fn <Equatable as std::ops::Add<u32>>::add
     fn add(self, rhs: u32) -> u32 {
         self.0 + rhs
     }
 }
 
-impl Deref for _Equatable {
+impl Deref for Equatable {
     type Target = u32;
 
-    //~ MONO_ITEM fn <_Equatable as std::ops::Deref>::deref
+    //~ MONO_ITEM fn <Equatable as std::ops::Deref>::deref
     fn deref(&self) -> &Self::Target {
         &self.0
     }
diff --git a/tests/codegen/iter-repeat-n-trivial-drop.rs b/tests/codegen/iter-repeat-n-trivial-drop.rs
index 31020b77984..7de224b92d8 100644
--- a/tests/codegen/iter-repeat-n-trivial-drop.rs
+++ b/tests/codegen/iter-repeat-n-trivial-drop.rs
@@ -1,8 +1,9 @@
-//@ compile-flags: -O
+//@ compile-flags: -C opt-level=3
 //@ only-x86_64
 
 #![crate_type = "lib"]
 #![feature(iter_repeat_n)]
+#![feature(array_repeat)]
 
 #[derive(Clone)]
 pub struct NotCopy(u16);
@@ -54,3 +55,15 @@ pub fn vec_extend_via_iter_repeat_n() -> Vec<u8> {
     v.extend(std::iter::repeat_n(42_u8, n));
     v
 }
+
+// Array repeat uses `RepeatN::next_unchecked` internally,
+// so also check that the distinction disappears there.
+
+#[no_mangle]
+// CHECK-LABEL: @array_repeat_not_copy
+pub unsafe fn array_repeat_not_copy(item: NotCopy) -> [NotCopy; 8] {
+    // CHECK: insertelement {{.+}} i16 %item
+    // CHECK: shufflevector <8 x i16> {{.+}} zeroinitializer
+    // CHECK: store <8 x i16>
+    std::array::repeat(item)
+}
diff --git a/tests/mir-opt/matches_reduce_branches.match_i128_u128.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_i128_u128.MatchBranchSimplification.diff
index dc50ae95472..fc34ce7125e 100644
--- a/tests/mir-opt/matches_reduce_branches.match_i128_u128.MatchBranchSimplification.diff
+++ b/tests/mir-opt/matches_reduce_branches.match_i128_u128.MatchBranchSimplification.diff
@@ -5,37 +5,42 @@
       debug i => _1;
       let mut _0: u128;
       let mut _2: i128;
++     let mut _3: i128;
   
       bb0: {
           _2 = discriminant(_1);
-          switchInt(move _2) -> [1: bb5, 2: bb4, 3: bb3, 340282366920938463463374607431768211455: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const core::num::<impl u128>::MAX;
-          goto -> bb6;
-      }
-  
-      bb3: {
-          _0 = const 3_u128;
-          goto -> bb6;
-      }
-  
-      bb4: {
-          _0 = const 2_u128;
-          goto -> bb6;
-      }
-  
-      bb5: {
-          _0 = const 1_u128;
-          goto -> bb6;
-      }
-  
-      bb6: {
+-         switchInt(move _2) -> [1: bb5, 2: bb4, 3: bb3, 340282366920938463463374607431768211455: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const core::num::<impl u128>::MAX;
+-         goto -> bb6;
+-     }
+- 
+-     bb3: {
+-         _0 = const 3_u128;
+-         goto -> bb6;
+-     }
+- 
+-     bb4: {
+-         _0 = const 2_u128;
+-         goto -> bb6;
+-     }
+- 
+-     bb5: {
+-         _0 = const 1_u128;
+-         goto -> bb6;
+-     }
+- 
+-     bb6: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u128 (IntToInt);
++         StorageDead(_3);
           return;
       }
   }
diff --git a/tests/mir-opt/matches_reduce_branches.match_i16_i8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_i16_i8.MatchBranchSimplification.diff
deleted file mode 100644
index 3514914b8ec..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_i16_i8.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,37 +0,0 @@
-- // MIR for `match_i16_i8` before MatchBranchSimplification
-+ // MIR for `match_i16_i8` after MatchBranchSimplification
-  
-  fn match_i16_i8(_1: EnumAi16) -> i8 {
-      debug i => _1;
-      let mut _0: i8;
-      let mut _2: i16;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [65535: bb4, 2: bb3, 65533: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const -3_i8;
-          goto -> bb5;
-      }
-  
-      bb3: {
-          _0 = const 2_i8;
-          goto -> bb5;
-      }
-  
-      bb4: {
-          _0 = const -1_i8;
-          goto -> bb5;
-      }
-  
-      bb5: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_i8_i16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_i8_i16.MatchBranchSimplification.diff
deleted file mode 100644
index ff4255ec8cc..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_i8_i16.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,37 +0,0 @@
-- // MIR for `match_i8_i16` before MatchBranchSimplification
-+ // MIR for `match_i8_i16` after MatchBranchSimplification
-  
-  fn match_i8_i16(_1: EnumAi8) -> i16 {
-      debug i => _1;
-      let mut _0: i16;
-      let mut _2: i8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [255: bb4, 2: bb3, 253: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const -3_i16;
-          goto -> bb5;
-      }
-  
-      bb3: {
-          _0 = const 2_i16;
-          goto -> bb5;
-      }
-  
-      bb4: {
-          _0 = const -1_i16;
-          goto -> bb5;
-      }
-  
-      bb5: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_i8_i16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_i8_i16_failed.MatchBranchSimplification.diff
deleted file mode 100644
index 022039ecee6..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_i8_i16_failed.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,37 +0,0 @@
-- // MIR for `match_i8_i16_failed` before MatchBranchSimplification
-+ // MIR for `match_i8_i16_failed` after MatchBranchSimplification
-  
-  fn match_i8_i16_failed(_1: EnumAi8) -> i16 {
-      debug i => _1;
-      let mut _0: i16;
-      let mut _2: i8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [255: bb4, 2: bb3, 253: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 3_i16;
-          goto -> bb5;
-      }
-  
-      bb3: {
-          _0 = const 2_i16;
-          goto -> bb5;
-      }
-  
-      bb4: {
-          _0 = const -1_i16;
-          goto -> bb5;
-      }
-  
-      bb5: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..7f8c2ab8d37
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16.MatchBranchSimplification.diff
@@ -0,0 +1,52 @@
+- // MIR for `match_sext_i8_i16` before MatchBranchSimplification
++ // MIR for `match_sext_i8_i16` after MatchBranchSimplification
+  
+  fn match_sext_i8_i16(_1: EnumAi8) -> i16 {
+      debug i => _1;
+      let mut _0: i16;
+      let mut _2: i8;
++     let mut _3: i8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [128: bb6, 255: bb5, 0: bb4, 1: bb3, 127: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 127_i16;
+-         goto -> bb7;
+-     }
+- 
+-     bb3: {
+-         _0 = const 1_i16;
+-         goto -> bb7;
+-     }
+- 
+-     bb4: {
+-         _0 = const 0_i16;
+-         goto -> bb7;
+-     }
+- 
+-     bb5: {
+-         _0 = const -1_i16;
+-         goto -> bb7;
+-     }
+- 
+-     bb6: {
+-         _0 = const -128_i16;
+-         goto -> bb7;
+-     }
+- 
+-     bb7: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i16 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..94ec2293222
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_sext_i8_i16_failed.MatchBranchSimplification.diff
@@ -0,0 +1,47 @@
+- // MIR for `match_sext_i8_i16_failed` before MatchBranchSimplification
++ // MIR for `match_sext_i8_i16_failed` after MatchBranchSimplification
+  
+  fn match_sext_i8_i16_failed(_1: EnumAi8) -> i16 {
+      debug i => _1;
+      let mut _0: i16;
+      let mut _2: i8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [128: bb6, 255: bb5, 0: bb4, 1: bb3, 127: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 127_i16;
+          goto -> bb7;
+      }
+  
+      bb3: {
+          _0 = const 1_i16;
+          goto -> bb7;
+      }
+  
+      bb4: {
+          _0 = const 0_i16;
+          goto -> bb7;
+      }
+  
+      bb5: {
+          _0 = const 255_i16;
+          goto -> bb7;
+      }
+  
+      bb6: {
+          _0 = const -128_i16;
+          goto -> bb7;
+      }
+  
+      bb7: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..86d0d0ba6cf
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16.MatchBranchSimplification.diff
@@ -0,0 +1,52 @@
+- // MIR for `match_sext_i8_u16` before MatchBranchSimplification
++ // MIR for `match_sext_i8_u16` after MatchBranchSimplification
+  
+  fn match_sext_i8_u16(_1: EnumAi8) -> u16 {
+      debug i => _1;
+      let mut _0: u16;
+      let mut _2: i8;
++     let mut _3: i8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [128: bb6, 255: bb5, 0: bb4, 1: bb3, 127: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 127_u16;
+-         goto -> bb7;
+-     }
+- 
+-     bb3: {
+-         _0 = const 1_u16;
+-         goto -> bb7;
+-     }
+- 
+-     bb4: {
+-         _0 = const 0_u16;
+-         goto -> bb7;
+-     }
+- 
+-     bb5: {
+-         _0 = const u16::MAX;
+-         goto -> bb7;
+-     }
+- 
+-     bb6: {
+-         _0 = const 65408_u16;
+-         goto -> bb7;
+-     }
+- 
+-     bb7: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u16 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..281f373bf87
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_sext_i8_u16_failed.MatchBranchSimplification.diff
@@ -0,0 +1,47 @@
+- // MIR for `match_sext_i8_u16_failed` before MatchBranchSimplification
++ // MIR for `match_sext_i8_u16_failed` after MatchBranchSimplification
+  
+  fn match_sext_i8_u16_failed(_1: EnumAi8) -> u16 {
+      debug i => _1;
+      let mut _0: u16;
+      let mut _2: i8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [128: bb6, 255: bb5, 0: bb4, 1: bb3, 127: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 127_u16;
+          goto -> bb7;
+      }
+  
+      bb3: {
+          _0 = const 1_u16;
+          goto -> bb7;
+      }
+  
+      bb4: {
+          _0 = const 0_u16;
+          goto -> bb7;
+      }
+  
+      bb5: {
+          _0 = const 255_u16;
+          goto -> bb7;
+      }
+  
+      bb6: {
+          _0 = const 65408_u16;
+          goto -> bb7;
+      }
+  
+      bb7: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..d3d27be2070
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8.MatchBranchSimplification.diff
@@ -0,0 +1,77 @@
+- // MIR for `match_trunc_i16_i8` before MatchBranchSimplification
++ // MIR for `match_trunc_i16_i8` after MatchBranchSimplification
+  
+  fn match_trunc_i16_i8(_1: EnumAi16) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: i16;
++     let mut _3: i16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [128: bb11, 255: bb10, 0: bb9, 1: bb8, 127: bb7, 65408: bb6, 65535: bb5, 65280: bb4, 65281: bb3, 65407: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const i8::MAX;
+-         goto -> bb12;
+-     }
+- 
+-     bb3: {
+-         _0 = const 1_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb4: {
+-         _0 = const 0_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb5: {
+-         _0 = const -1_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb6: {
+-         _0 = const i8::MIN;
+-         goto -> bb12;
+-     }
+- 
+-     bb7: {
+-         _0 = const i8::MAX;
+-         goto -> bb12;
+-     }
+- 
+-     bb8: {
+-         _0 = const 1_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb9: {
+-         _0 = const 0_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb10: {
+-         _0 = const -1_i8;
+-         goto -> bb12;
+-     }
+- 
+-     bb11: {
+-         _0 = const i8::MIN;
+-         goto -> bb12;
+-     }
+- 
+-     bb12: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i8 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..7f663baefba
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_i8_failed.MatchBranchSimplification.diff
@@ -0,0 +1,72 @@
+- // MIR for `match_trunc_i16_i8_failed` before MatchBranchSimplification
++ // MIR for `match_trunc_i16_i8_failed` after MatchBranchSimplification
+  
+  fn match_trunc_i16_i8_failed(_1: EnumAi16) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: i16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [128: bb11, 255: bb10, 0: bb9, 1: bb8, 127: bb7, 65408: bb6, 65535: bb5, 65280: bb4, 65281: bb3, 65407: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const -127_i8;
+          goto -> bb12;
+      }
+  
+      bb3: {
+          _0 = const 1_i8;
+          goto -> bb12;
+      }
+  
+      bb4: {
+          _0 = const 0_i8;
+          goto -> bb12;
+      }
+  
+      bb5: {
+          _0 = const -1_i8;
+          goto -> bb12;
+      }
+  
+      bb6: {
+          _0 = const i8::MIN;
+          goto -> bb12;
+      }
+  
+      bb7: {
+          _0 = const i8::MAX;
+          goto -> bb12;
+      }
+  
+      bb8: {
+          _0 = const 1_i8;
+          goto -> bb12;
+      }
+  
+      bb9: {
+          _0 = const 0_i8;
+          goto -> bb12;
+      }
+  
+      bb10: {
+          _0 = const -1_i8;
+          goto -> bb12;
+      }
+  
+      bb11: {
+          _0 = const i8::MIN;
+          goto -> bb12;
+      }
+  
+      bb12: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..5fe899148eb
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8.MatchBranchSimplification.diff
@@ -0,0 +1,77 @@
+- // MIR for `match_trunc_i16_u8` before MatchBranchSimplification
++ // MIR for `match_trunc_i16_u8` after MatchBranchSimplification
+  
+  fn match_trunc_i16_u8(_1: EnumAi16) -> u8 {
+      debug i => _1;
+      let mut _0: u8;
+      let mut _2: i16;
++     let mut _3: i16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [128: bb11, 255: bb10, 0: bb9, 1: bb8, 127: bb7, 65408: bb6, 65535: bb5, 65280: bb4, 65281: bb3, 65407: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 127_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb3: {
+-         _0 = const 1_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb4: {
+-         _0 = const 0_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb5: {
+-         _0 = const u8::MAX;
+-         goto -> bb12;
+-     }
+- 
+-     bb6: {
+-         _0 = const 128_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb7: {
+-         _0 = const 127_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb8: {
+-         _0 = const 1_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb9: {
+-         _0 = const 0_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb10: {
+-         _0 = const u8::MAX;
+-         goto -> bb12;
+-     }
+- 
+-     bb11: {
+-         _0 = const 128_u8;
+-         goto -> bb12;
+-     }
+- 
+-     bb12: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u8 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..1c0ffb30c5b
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_i16_u8_failed.MatchBranchSimplification.diff
@@ -0,0 +1,72 @@
+- // MIR for `match_trunc_i16_u8_failed` before MatchBranchSimplification
++ // MIR for `match_trunc_i16_u8_failed` after MatchBranchSimplification
+  
+  fn match_trunc_i16_u8_failed(_1: EnumAi16) -> u8 {
+      debug i => _1;
+      let mut _0: u8;
+      let mut _2: i16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [128: bb11, 255: bb10, 0: bb9, 1: bb8, 127: bb7, 65408: bb6, 65535: bb5, 65280: bb4, 65281: bb3, 65407: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const -127_i8 as u8 (IntToInt);
+          goto -> bb12;
+      }
+  
+      bb3: {
+          _0 = const 1_u8;
+          goto -> bb12;
+      }
+  
+      bb4: {
+          _0 = const 0_u8;
+          goto -> bb12;
+      }
+  
+      bb5: {
+          _0 = const u8::MAX;
+          goto -> bb12;
+      }
+  
+      bb6: {
+          _0 = const 128_u8;
+          goto -> bb12;
+      }
+  
+      bb7: {
+          _0 = const 127_u8;
+          goto -> bb12;
+      }
+  
+      bb8: {
+          _0 = const 1_u8;
+          goto -> bb12;
+      }
+  
+      bb9: {
+          _0 = const 0_u8;
+          goto -> bb12;
+      }
+  
+      bb10: {
+          _0 = const u8::MAX;
+          goto -> bb12;
+      }
+  
+      bb11: {
+          _0 = const 128_u8;
+          goto -> bb12;
+      }
+  
+      bb12: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..85f97a13cac
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8.MatchBranchSimplification.diff
@@ -0,0 +1,67 @@
+- // MIR for `match_trunc_u16_i8` before MatchBranchSimplification
++ // MIR for `match_trunc_u16_i8` after MatchBranchSimplification
+  
+  fn match_trunc_u16_i8(_1: EnumAu16) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: u16;
++     let mut _3: u16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [0: bb9, 127: bb8, 128: bb7, 255: bb6, 65280: bb5, 65407: bb4, 65408: bb3, 65535: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const -1_i8;
+-         goto -> bb10;
+-     }
+- 
+-     bb3: {
+-         _0 = const i8::MIN;
+-         goto -> bb10;
+-     }
+- 
+-     bb4: {
+-         _0 = const i8::MAX;
+-         goto -> bb10;
+-     }
+- 
+-     bb5: {
+-         _0 = const 0_i8;
+-         goto -> bb10;
+-     }
+- 
+-     bb6: {
+-         _0 = const -1_i8;
+-         goto -> bb10;
+-     }
+- 
+-     bb7: {
+-         _0 = const i8::MIN;
+-         goto -> bb10;
+-     }
+- 
+-     bb8: {
+-         _0 = const i8::MAX;
+-         goto -> bb10;
+-     }
+- 
+-     bb9: {
+-         _0 = const 0_i8;
+-         goto -> bb10;
+-     }
+- 
+-     bb10: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i8 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..cf6c86a71ad
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_i8_failed.MatchBranchSimplification.diff
@@ -0,0 +1,62 @@
+- // MIR for `match_trunc_u16_i8_failed` before MatchBranchSimplification
++ // MIR for `match_trunc_u16_i8_failed` after MatchBranchSimplification
+  
+  fn match_trunc_u16_i8_failed(_1: EnumAu16) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: u16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb9, 127: bb8, 128: bb7, 255: bb6, 65280: bb5, 65407: bb4, 65408: bb3, 65535: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 1_i8;
+          goto -> bb10;
+      }
+  
+      bb3: {
+          _0 = const i8::MIN;
+          goto -> bb10;
+      }
+  
+      bb4: {
+          _0 = const i8::MAX;
+          goto -> bb10;
+      }
+  
+      bb5: {
+          _0 = const 0_i8;
+          goto -> bb10;
+      }
+  
+      bb6: {
+          _0 = const -1_i8;
+          goto -> bb10;
+      }
+  
+      bb7: {
+          _0 = const i8::MIN;
+          goto -> bb10;
+      }
+  
+      bb8: {
+          _0 = const i8::MAX;
+          goto -> bb10;
+      }
+  
+      bb9: {
+          _0 = const 0_i8;
+          goto -> bb10;
+      }
+  
+      bb10: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..768d838eaa6
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8.MatchBranchSimplification.diff
@@ -0,0 +1,67 @@
+- // MIR for `match_trunc_u16_u8` before MatchBranchSimplification
++ // MIR for `match_trunc_u16_u8` after MatchBranchSimplification
+  
+  fn match_trunc_u16_u8(_1: EnumAu16) -> u8 {
+      debug i => _1;
+      let mut _0: u8;
+      let mut _2: u16;
++     let mut _3: u16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [0: bb9, 127: bb8, 128: bb7, 255: bb6, 65280: bb5, 65407: bb4, 65408: bb3, 65535: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const u8::MAX;
+-         goto -> bb10;
+-     }
+- 
+-     bb3: {
+-         _0 = const 128_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb4: {
+-         _0 = const 127_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb5: {
+-         _0 = const 0_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb6: {
+-         _0 = const u8::MAX;
+-         goto -> bb10;
+-     }
+- 
+-     bb7: {
+-         _0 = const 128_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb8: {
+-         _0 = const 127_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb9: {
+-         _0 = const 0_u8;
+-         goto -> bb10;
+-     }
+- 
+-     bb10: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u8 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..109e97bb578
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_trunc_u16_u8_failed.MatchBranchSimplification.diff
@@ -0,0 +1,62 @@
+- // MIR for `match_trunc_u16_u8_failed` before MatchBranchSimplification
++ // MIR for `match_trunc_u16_u8_failed` after MatchBranchSimplification
+  
+  fn match_trunc_u16_u8_failed(_1: EnumAu16) -> u8 {
+      debug i => _1;
+      let mut _0: u8;
+      let mut _2: u16;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb9, 127: bb8, 128: bb7, 255: bb6, 65280: bb5, 65407: bb4, 65408: bb3, 65535: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 127_u8;
+          goto -> bb10;
+      }
+  
+      bb3: {
+          _0 = const 128_u8;
+          goto -> bb10;
+      }
+  
+      bb4: {
+          _0 = const 127_u8;
+          goto -> bb10;
+      }
+  
+      bb5: {
+          _0 = const 0_u8;
+          goto -> bb10;
+      }
+  
+      bb6: {
+          _0 = const u8::MAX;
+          goto -> bb10;
+      }
+  
+      bb7: {
+          _0 = const 128_u8;
+          goto -> bb10;
+      }
+  
+      bb8: {
+          _0 = const 127_u8;
+          goto -> bb10;
+      }
+  
+      bb9: {
+          _0 = const 0_u8;
+          goto -> bb10;
+      }
+  
+      bb10: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i16.MatchBranchSimplification.diff
deleted file mode 100644
index 72ad60956ab..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_i16.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,32 +0,0 @@
-- // MIR for `match_u8_i16` before MatchBranchSimplification
-+ // MIR for `match_u8_i16` after MatchBranchSimplification
-  
-  fn match_u8_i16(_1: EnumAu8) -> i16 {
-      debug i => _1;
-      let mut _0: i16;
-      let mut _2: u8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [1: bb3, 2: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 2_i16;
-          goto -> bb4;
-      }
-  
-      bb3: {
-          _0 = const 1_i16;
-          goto -> bb4;
-      }
-  
-      bb4: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i16_2.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i16_2.MatchBranchSimplification.diff
deleted file mode 100644
index 3333cd765a8..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_i16_2.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,26 +0,0 @@
-- // MIR for `match_u8_i16_2` before MatchBranchSimplification
-+ // MIR for `match_u8_i16_2` after MatchBranchSimplification
-  
-  fn match_u8_i16_2(_1: EnumAu8) -> i16 {
-      let mut _0: i16;
-      let mut _2: u8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(_2) -> [1: bb3, 2: bb1, otherwise: bb2];
-      }
-  
-      bb1: {
-          _0 = const 2_i16;
-          goto -> bb3;
-      }
-  
-      bb2: {
-          unreachable;
-      }
-  
-      bb3: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i16_failed.MatchBranchSimplification.diff
deleted file mode 100644
index 6da19e46dab..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_i16_failed.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,32 +0,0 @@
-- // MIR for `match_u8_i16_failed` before MatchBranchSimplification
-+ // MIR for `match_u8_i16_failed` after MatchBranchSimplification
-  
-  fn match_u8_i16_failed(_1: EnumAu8) -> i16 {
-      debug i => _1;
-      let mut _0: i16;
-      let mut _2: u8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [1: bb3, 2: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 3_i16;
-          goto -> bb4;
-      }
-  
-      bb3: {
-          _0 = const 1_i16;
-          goto -> bb4;
-      }
-  
-      bb4: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i16_fallback.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i16_fallback.MatchBranchSimplification.diff
deleted file mode 100644
index 5690f17f24f..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_i16_fallback.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,31 +0,0 @@
-- // MIR for `match_u8_i16_fallback` before MatchBranchSimplification
-+ // MIR for `match_u8_i16_fallback` after MatchBranchSimplification
-  
-  fn match_u8_i16_fallback(_1: u8) -> i16 {
-      debug i => _1;
-      let mut _0: i16;
-  
-      bb0: {
-          switchInt(_1) -> [1: bb3, 2: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          _0 = const 3_i16;
-          goto -> bb4;
-      }
-  
-      bb2: {
-          _0 = const 2_i16;
-          goto -> bb4;
-      }
-  
-      bb3: {
-          _0 = const 1_i16;
-          goto -> bb4;
-      }
-  
-      bb4: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..d63eed7c019
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8.MatchBranchSimplification.diff
@@ -0,0 +1,47 @@
+- // MIR for `match_u8_i8` before MatchBranchSimplification
++ // MIR for `match_u8_i8` after MatchBranchSimplification
+  
+  fn match_u8_i8(_1: EnumAu8) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: u8;
++     let mut _3: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const -1_i8;
+-         goto -> bb6;
+-     }
+- 
+-     bb3: {
+-         _0 = const i8::MIN;
+-         goto -> bb6;
+-     }
+- 
+-     bb4: {
+-         _0 = const i8::MAX;
+-         goto -> bb6;
+-     }
+- 
+-     bb5: {
+-         _0 = const 0_i8;
+-         goto -> bb6;
+-     }
+- 
+-     bb6: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i8 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_2.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_2.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..98dee1835a8
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_2.MatchBranchSimplification.diff
@@ -0,0 +1,80 @@
+- // MIR for `match_u8_i8_2` before MatchBranchSimplification
++ // MIR for `match_u8_i8_2` after MatchBranchSimplification
+  
+  fn match_u8_i8_2(_1: EnumAu8) -> (i8, i8) {
+      debug i => _1;
+      let mut _0: (i8, i8);
+      let _2: i8;
+      let _4: ();
+      let mut _5: u8;
+      let mut _6: i8;
+      let mut _7: i8;
++     let mut _8: u8;
+      scope 1 {
+          debug a => _2;
+          let _3: i8;
+          scope 2 {
+              debug b => _3;
+          }
+      }
+  
+      bb0: {
+          StorageLive(_2);
+          StorageLive(_3);
+          StorageLive(_4);
+          _5 = discriminant(_1);
+-         switchInt(move _5) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _2 = const -1_i8;
+-         _3 = const -1_i8;
++         StorageLive(_8);
++         _8 = move _5;
++         _2 = _8 as i8 (IntToInt);
++         _3 = _8 as i8 (IntToInt);
+          _4 = ();
+-         goto -> bb6;
+-     }
+- 
+-     bb3: {
+-         _2 = const i8::MIN;
+-         _3 = const i8::MIN;
+-         _4 = ();
+-         goto -> bb6;
+-     }
+- 
+-     bb4: {
+-         _2 = const i8::MAX;
+-         _3 = const i8::MAX;
+-         _4 = ();
+-         goto -> bb6;
+-     }
+- 
+-     bb5: {
+-         _2 = const 0_i8;
+-         _3 = const 0_i8;
+-         _4 = ();
+-         goto -> bb6;
+-     }
+- 
+-     bb6: {
++         StorageDead(_8);
+          StorageDead(_4);
+          StorageLive(_6);
+          _6 = _2;
+          StorageLive(_7);
+          _7 = _3;
+          _0 = (move _6, move _7);
+          StorageDead(_7);
+          StorageDead(_6);
+          StorageDead(_3);
+          StorageDead(_2);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_2_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_2_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..901dda58617
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_2_failed.MatchBranchSimplification.diff
@@ -0,0 +1,74 @@
+- // MIR for `match_u8_i8_2_failed` before MatchBranchSimplification
++ // MIR for `match_u8_i8_2_failed` after MatchBranchSimplification
+  
+  fn match_u8_i8_2_failed(_1: EnumAu8) -> (i8, i8) {
+      debug i => _1;
+      let mut _0: (i8, i8);
+      let _2: i8;
+      let _4: ();
+      let mut _5: u8;
+      let mut _6: i8;
+      let mut _7: i8;
+      scope 1 {
+          debug a => _2;
+          let _3: i8;
+          scope 2 {
+              debug b => _3;
+          }
+      }
+  
+      bb0: {
+          StorageLive(_2);
+          StorageLive(_3);
+          StorageLive(_4);
+          _5 = discriminant(_1);
+          switchInt(move _5) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _2 = const -1_i8;
+          _3 = const 1_i8;
+          _4 = ();
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _2 = const i8::MIN;
+          _3 = const i8::MIN;
+          _4 = ();
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _2 = const i8::MAX;
+          _3 = const i8::MAX;
+          _4 = ();
+          goto -> bb6;
+      }
+  
+      bb5: {
+          _2 = const 0_i8;
+          _3 = const 0_i8;
+          _4 = ();
+          goto -> bb6;
+      }
+  
+      bb6: {
+          StorageDead(_4);
+          StorageLive(_6);
+          _6 = _2;
+          StorageLive(_7);
+          _7 = _3;
+          _0 = (move _6, move _7);
+          StorageDead(_7);
+          StorageDead(_6);
+          StorageDead(_3);
+          StorageDead(_2);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..ac96be55312
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed.MatchBranchSimplification.diff
@@ -0,0 +1,42 @@
+- // MIR for `match_u8_i8_failed` before MatchBranchSimplification
++ // MIR for `match_u8_i8_failed` after MatchBranchSimplification
+  
+  fn match_u8_i8_failed(_1: EnumAu8) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 1_i8;
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _0 = const i8::MIN;
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _0 = const i8::MAX;
+          goto -> bb6;
+      }
+  
+      bb5: {
+          _0 = const 0_i8;
+          goto -> bb6;
+      }
+  
+      bb6: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_1.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_1.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..9ebf2cf27cb
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_1.MatchBranchSimplification.diff
@@ -0,0 +1,42 @@
+- // MIR for `match_u8_i8_failed_len_1` before MatchBranchSimplification
++ // MIR for `match_u8_i8_failed_len_1` after MatchBranchSimplification
+  
+  fn match_u8_i8_failed_len_1(_1: EnumAu8) -> i8 {
+      let mut _0: i8;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(_2) -> [0: bb1, 127: bb2, 128: bb3, 255: bb4, otherwise: bb5];
+      }
+  
+      bb1: {
+          _0 = const 0_i8;
+          goto -> bb6;
+      }
+  
+      bb2: {
+          _0 = const i8::MAX;
+          _0 = const i8::MAX;
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _0 = const i8::MIN;
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _0 = const -1_i8;
+          goto -> bb6;
+      }
+  
+      bb5: {
+          unreachable;
+      }
+  
+      bb6: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_2.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_2.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..554856777eb
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_failed_len_2.MatchBranchSimplification.diff
@@ -0,0 +1,42 @@
+- // MIR for `match_u8_i8_failed_len_2` before MatchBranchSimplification
++ // MIR for `match_u8_i8_failed_len_2` after MatchBranchSimplification
+  
+  fn match_u8_i8_failed_len_2(_1: EnumAu8) -> i8 {
+      let mut _0: i8;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(_2) -> [0: bb1, 127: bb2, 128: bb3, 255: bb4, otherwise: bb5];
+      }
+  
+      bb1: {
+          _0 = const 0_i8;
+          goto -> bb6;
+      }
+  
+      bb2: {
+          _0 = const i8::MAX;
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _0 = const i8::MIN;
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _0 = const -1_i8;
+          _0 = const -1_i8;
+          goto -> bb6;
+      }
+  
+      bb5: {
+          unreachable;
+      }
+  
+      bb6: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_i8_fallback.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_i8_fallback.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..356655021f7
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_u8_i8_fallback.MatchBranchSimplification.diff
@@ -0,0 +1,38 @@
+- // MIR for `match_u8_i8_fallback` before MatchBranchSimplification
++ // MIR for `match_u8_i8_fallback` after MatchBranchSimplification
+  
+  fn match_u8_i8_fallback(_1: EnumAu8) -> i8 {
+      debug i => _1;
+      let mut _0: i8;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb4, 127: bb3, 128: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          _0 = const -1_i8;
+          goto -> bb5;
+      }
+  
+      bb2: {
+          _0 = const i8::MIN;
+          goto -> bb5;
+      }
+  
+      bb3: {
+          _0 = const i8::MAX;
+          goto -> bb5;
+      }
+  
+      bb4: {
+          _0 = const 0_i8;
+          goto -> bb5;
+      }
+  
+      bb5: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_u16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_u16.MatchBranchSimplification.diff
deleted file mode 100644
index dc9c1c2b97f..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_u16.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,37 +0,0 @@
-- // MIR for `match_u8_u16` before MatchBranchSimplification
-+ // MIR for `match_u8_u16` after MatchBranchSimplification
-  
-  fn match_u8_u16(_1: EnumBu8) -> u16 {
-      debug i => _1;
-      let mut _0: u16;
-      let mut _2: u8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(move _2) -> [1: bb4, 2: bb3, 5: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 5_u16;
-          goto -> bb5;
-      }
-  
-      bb3: {
-          _0 = const 2_u16;
-          goto -> bb5;
-      }
-  
-      bb4: {
-          _0 = const 1_u16;
-          goto -> bb5;
-      }
-  
-      bb5: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_u8_u16_2.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_u8_u16_2.MatchBranchSimplification.diff
deleted file mode 100644
index b47de6a52b7..00000000000
--- a/tests/mir-opt/matches_reduce_branches.match_u8_u16_2.MatchBranchSimplification.diff
+++ /dev/null
@@ -1,37 +0,0 @@
-- // MIR for `match_u8_u16_2` before MatchBranchSimplification
-+ // MIR for `match_u8_u16_2` after MatchBranchSimplification
-  
-  fn match_u8_u16_2(_1: EnumBu8) -> i16 {
-      let mut _0: i16;
-      let mut _2: u8;
-  
-      bb0: {
-          _2 = discriminant(_1);
-          switchInt(_2) -> [1: bb1, 2: bb2, 5: bb3, otherwise: bb4];
-      }
-  
-      bb1: {
-          _0 = const 1_i16;
-          goto -> bb5;
-      }
-  
-      bb2: {
-          _0 = const 2_i16;
-          goto -> bb5;
-      }
-  
-      bb3: {
-          _0 = const 5_i16;
-          _0 = const 5_i16;
-          goto -> bb5;
-      }
-  
-      bb4: {
-          unreachable;
-      }
-  
-      bb5: {
-          return;
-      }
-  }
-  
diff --git a/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..e00a604fe25
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16.MatchBranchSimplification.diff
@@ -0,0 +1,47 @@
+- // MIR for `match_zext_u8_i16` before MatchBranchSimplification
++ // MIR for `match_zext_u8_i16` after MatchBranchSimplification
+  
+  fn match_zext_u8_i16(_1: EnumAu8) -> i16 {
+      debug i => _1;
+      let mut _0: i16;
+      let mut _2: u8;
++     let mut _3: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 255_i16;
+-         goto -> bb6;
+-     }
+- 
+-     bb3: {
+-         _0 = const 128_i16;
+-         goto -> bb6;
+-     }
+- 
+-     bb4: {
+-         _0 = const 127_i16;
+-         goto -> bb6;
+-     }
+- 
+-     bb5: {
+-         _0 = const 0_i16;
+-         goto -> bb6;
+-     }
+- 
+-     bb6: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i16 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..a19cd796c27
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_zext_u8_i16_failed.MatchBranchSimplification.diff
@@ -0,0 +1,42 @@
+- // MIR for `match_zext_u8_i16_failed` before MatchBranchSimplification
++ // MIR for `match_zext_u8_i16_failed` after MatchBranchSimplification
+  
+  fn match_zext_u8_i16_failed(_1: EnumAu8) -> i16 {
+      debug i => _1;
+      let mut _0: i16;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 255_i16;
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _0 = const 128_i16;
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _0 = const -127_i16;
+          goto -> bb6;
+      }
+  
+      bb5: {
+          _0 = const 0_i16;
+          goto -> bb6;
+      }
+  
+      bb6: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..befb9118907
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16.MatchBranchSimplification.diff
@@ -0,0 +1,47 @@
+- // MIR for `match_zext_u8_u16` before MatchBranchSimplification
++ // MIR for `match_zext_u8_u16` after MatchBranchSimplification
+  
+  fn match_zext_u8_u16(_1: EnumAu8) -> u16 {
+      debug i => _1;
+      let mut _0: u16;
+      let mut _2: u8;
++     let mut _3: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+-         switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 255_u16;
+-         goto -> bb6;
+-     }
+- 
+-     bb3: {
+-         _0 = const 128_u16;
+-         goto -> bb6;
+-     }
+- 
+-     bb4: {
+-         _0 = const 127_u16;
+-         goto -> bb6;
+-     }
+- 
+-     bb5: {
+-         _0 = const 0_u16;
+-         goto -> bb6;
+-     }
+- 
+-     bb6: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u16 (IntToInt);
++         StorageDead(_3);
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16_failed.MatchBranchSimplification.diff b/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16_failed.MatchBranchSimplification.diff
new file mode 100644
index 00000000000..f781f88449d
--- /dev/null
+++ b/tests/mir-opt/matches_reduce_branches.match_zext_u8_u16_failed.MatchBranchSimplification.diff
@@ -0,0 +1,42 @@
+- // MIR for `match_zext_u8_u16_failed` before MatchBranchSimplification
++ // MIR for `match_zext_u8_u16_failed` after MatchBranchSimplification
+  
+  fn match_zext_u8_u16_failed(_1: EnumAu8) -> u16 {
+      debug i => _1;
+      let mut _0: u16;
+      let mut _2: u8;
+  
+      bb0: {
+          _2 = discriminant(_1);
+          switchInt(move _2) -> [0: bb5, 127: bb4, 128: bb3, 255: bb2, otherwise: bb1];
+      }
+  
+      bb1: {
+          unreachable;
+      }
+  
+      bb2: {
+          _0 = const 255_u16;
+          goto -> bb6;
+      }
+  
+      bb3: {
+          _0 = const 128_u16;
+          goto -> bb6;
+      }
+  
+      bb4: {
+          _0 = const 65407_u16;
+          goto -> bb6;
+      }
+  
+      bb5: {
+          _0 = const 0_u16;
+          goto -> bb6;
+      }
+  
+      bb6: {
+          return;
+      }
+  }
+  
diff --git a/tests/mir-opt/matches_reduce_branches.rs b/tests/mir-opt/matches_reduce_branches.rs
index 176d68bcd40..6787e5816a3 100644
--- a/tests/mir-opt/matches_reduce_branches.rs
+++ b/tests/mir-opt/matches_reduce_branches.rs
@@ -3,6 +3,7 @@
 #![feature(repr128)]
 #![feature(core_intrinsics)]
 #![feature(custom_mir)]
+#![allow(non_camel_case_types)]
 
 use std::intrinsics::mir::*;
 
@@ -12,6 +13,7 @@ fn foo(bar: Option<()>) {
     // CHECK: = Eq(
     // CHECK: switchInt
     // CHECK-NOT: switchInt
+    // CHECK: return
     if matches!(bar, None) {
         ()
     }
@@ -23,6 +25,7 @@ fn bar(i: i32) -> (bool, bool, bool, bool) {
     // CHECK: = Ne(
     // CHECK: = Eq(
     // CHECK-NOT: switchInt
+    // CHECK: return
     let a;
     let b;
     let c;
@@ -52,6 +55,7 @@ fn bar(i: i32) -> (bool, bool, bool, bool) {
 fn match_nested_if() -> bool {
     // CHECK-LABEL: fn match_nested_if(
     // CHECK-NOT: switchInt
+    // CHECK: return
     let val = match () {
         () if if if if true { true } else { false } { true } else { false } {
             true
@@ -66,174 +70,528 @@ fn match_nested_if() -> bool {
     val
 }
 
+// # Fold switchInt into IntToInt.
+// To simplify writing and checking these test cases, I use the first character of
+// each case to distinguish the sign of the number:
+// 'u' for unsigned, '_' for negative, and 'o' for non-negative.
+// Followed by a decimal number, and add the corresponding radix representation.
+// For example, o127_0x7f represents 127i8, and _1_0xff represents -1i8.
+
+// ## Cast but without numeric conversion.
+
 #[repr(u8)]
 enum EnumAu8 {
-    A = 1,
-    B = 2,
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_i16.MatchBranchSimplification.diff
-fn match_u8_i16(i: EnumAu8) -> i16 {
-    // CHECK-LABEL: fn match_u8_i16(
-    // CHECK: switchInt
-    match i {
-        EnumAu8::A => 1,
-        EnumAu8::B => 2,
-    }
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_i16_2.MatchBranchSimplification.diff
-// Check for different instruction lengths
-#[custom_mir(dialect = "built")]
-fn match_u8_i16_2(i: EnumAu8) -> i16 {
-    // CHECK-LABEL: fn match_u8_i16_2(
-    // CHECK: switchInt
-    mir! {
-        {
-            let a = Discriminant(i);
-            match a {
-                1 => bb1,
-                2 => bb2,
-                _ => unreachable_bb,
-            }
-        }
-        bb1 = {
-            Goto(ret)
-        }
-        bb2 = {
-            RET = 2;
-            Goto(ret)
-        }
-        unreachable_bb = {
-            Unreachable()
-        }
-        ret = {
-            Return()
-        }
-    }
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_i16_failed.MatchBranchSimplification.diff
-fn match_u8_i16_failed(i: EnumAu8) -> i16 {
-    // CHECK-LABEL: fn match_u8_i16_failed(
-    // CHECK: switchInt
-    match i {
-        EnumAu8::A => 1,
-        EnumAu8::B => 3,
-    }
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_i16_fallback.MatchBranchSimplification.diff
-fn match_u8_i16_fallback(i: u8) -> i16 {
-    // CHECK-LABEL: fn match_u8_i16_fallback(
-    // CHECK: switchInt
-    match i {
-        1 => 1,
-        2 => 2,
-        _ => 3,
-    }
-}
-
-#[repr(u8)]
-enum EnumBu8 {
-    A = 1,
-    B = 2,
-    C = 5,
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_u16.MatchBranchSimplification.diff
-fn match_u8_u16(i: EnumBu8) -> u16 {
-    // CHECK-LABEL: fn match_u8_u16(
-    // CHECK: switchInt
-    match i {
-        EnumBu8::A => 1,
-        EnumBu8::B => 2,
-        EnumBu8::C => 5,
-    }
-}
-
-// EMIT_MIR matches_reduce_branches.match_u8_u16_2.MatchBranchSimplification.diff
-// Check for different instruction lengths
-#[custom_mir(dialect = "built")]
-fn match_u8_u16_2(i: EnumBu8) -> i16 {
-    // CHECK-LABEL: fn match_u8_u16_2(
-    // CHECK: switchInt
-    mir! {
-        {
-            let a = Discriminant(i);
-            match a {
-                1 => bb1,
-                2 => bb2,
-                5 => bb5,
-                _ => unreachable_bb,
-            }
-        }
-        bb1 = {
-            RET = 1;
-            Goto(ret)
-        }
-        bb2 = {
-            RET = 2;
-            Goto(ret)
-        }
-        bb5 = {
-            RET = 5;
-            RET = 5;
-            Goto(ret)
-        }
-        unreachable_bb = {
-            Unreachable()
-        }
-        ret = {
-            Return()
-        }
-    }
+    u0_0x00 = 0,
+    u127_0x7f = 127,
+    u128_0x80 = 128,
+    u255_0xff = 255,
 }
 
 #[repr(i8)]
 enum EnumAi8 {
-    A = -1,
-    B = 2,
-    C = -3,
+    _128_0x80 = -128,
+    _1_0xff = -1,
+    o0_0x00 = 0,
+    o1_0x01 = 1,
+    o127_0x7f = 127,
 }
 
-// EMIT_MIR matches_reduce_branches.match_i8_i16.MatchBranchSimplification.diff
-fn match_i8_i16(i: EnumAi8) -> i16 {
-    // CHECK-LABEL: fn match_i8_i16(
-    // CHECK: switchInt
+// EMIT_MIR matches_reduce_branches.match_u8_i8.MatchBranchSimplification.diff
+fn match_u8_i8(i: EnumAu8) -> i8 {
+    // CHECK-LABEL: fn match_u8_i8(
+    // CHECK-NOT: switchInt
+    // CHECK: return
     match i {
-        EnumAi8::A => -1,
-        EnumAi8::B => 2,
-        EnumAi8::C => -3,
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 127,
+        EnumAu8::u128_0x80 => -128,
+        EnumAu8::u255_0xff => -1,
     }
 }
 
-// EMIT_MIR matches_reduce_branches.match_i8_i16_failed.MatchBranchSimplification.diff
-fn match_i8_i16_failed(i: EnumAi8) -> i16 {
-    // CHECK-LABEL: fn match_i8_i16_failed(
+// EMIT_MIR matches_reduce_branches.match_u8_i8_failed.MatchBranchSimplification.diff
+fn match_u8_i8_failed(i: EnumAu8) -> i8 {
+    // CHECK-LABEL: fn match_u8_i8_failed(
     // CHECK: switchInt
+    // CHECK: return
     match i {
-        EnumAi8::A => -1,
-        EnumAi8::B => 2,
-        EnumAi8::C => 3,
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 127,
+        EnumAu8::u128_0x80 => -128,
+        EnumAu8::u255_0xff => 1, // failed
     }
 }
 
+// EMIT_MIR matches_reduce_branches.match_u8_i8_2.MatchBranchSimplification.diff
+fn match_u8_i8_2(i: EnumAu8) -> (i8, i8) {
+    // CHECK-LABEL: fn match_u8_i8_2(
+    // CHECK-NOT: switchInt
+    // CHECK: IntToInt
+    // CHECK: IntToInt
+    // CHECK: return
+    let a: i8;
+    let b: i8;
+    match i {
+        EnumAu8::u0_0x00 => {
+            a = 0;
+            b = 0;
+            ()
+        }
+        EnumAu8::u127_0x7f => {
+            a = 127;
+            b = 127;
+            ()
+        }
+        EnumAu8::u128_0x80 => {
+            a = -128;
+            b = -128;
+            ()
+        }
+        EnumAu8::u255_0xff => {
+            a = -1;
+            b = -1;
+            ()
+        }
+    };
+    (a, b)
+}
+
+// EMIT_MIR matches_reduce_branches.match_u8_i8_2_failed.MatchBranchSimplification.diff
+fn match_u8_i8_2_failed(i: EnumAu8) -> (i8, i8) {
+    // CHECK-LABEL: fn match_u8_i8_2_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    let a: i8;
+    let b: i8;
+    match i {
+        EnumAu8::u0_0x00 => {
+            a = 0;
+            b = 0;
+            ()
+        }
+        EnumAu8::u127_0x7f => {
+            a = 127;
+            b = 127;
+            ()
+        }
+        EnumAu8::u128_0x80 => {
+            a = -128;
+            b = -128;
+            ()
+        }
+        EnumAu8::u255_0xff => {
+            a = -1;
+            b = 1; // failed
+            ()
+        }
+    };
+    (a, b)
+}
+
+// EMIT_MIR matches_reduce_branches.match_u8_i8_fallback.MatchBranchSimplification.diff
+fn match_u8_i8_fallback(i: EnumAu8) -> i8 {
+    // CHECK-LABEL: fn match_u8_i8_fallback(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 127,
+        EnumAu8::u128_0x80 => -128,
+        _ => -1,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_u8_i8_failed_len_1.MatchBranchSimplification.diff
+// Check for different instruction lengths
+#[custom_mir(dialect = "built")]
+fn match_u8_i8_failed_len_1(i: EnumAu8) -> i8 {
+    // CHECK-LABEL: fn match_u8_i8_failed_len_1(
+    // CHECK: switchInt
+    // CHECK: return
+    mir! {
+        {
+            let a = Discriminant(i);
+            match a {
+                0 => bb1,
+                127 => bb2,
+                128 => bb3,
+                255 => bb4,
+                _ => unreachable_bb,
+            }
+        }
+        bb1 = {
+            RET = 0;
+            Goto(ret)
+        }
+        bb2 = {
+            RET = 127;
+            RET = 127;
+            Goto(ret)
+        }
+        bb3 = {
+            RET = -128;
+            Goto(ret)
+        }
+        bb4 = {
+            RET = -1;
+            Goto(ret)
+        }
+        unreachable_bb = {
+            Unreachable()
+        }
+        ret = {
+            Return()
+        }
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_u8_i8_failed_len_2.MatchBranchSimplification.diff
+// Check for different instruction lengths
+#[custom_mir(dialect = "built")]
+fn match_u8_i8_failed_len_2(i: EnumAu8) -> i8 {
+    // CHECK-LABEL: fn match_u8_i8_failed_len_2(
+    // CHECK: switchInt
+    // CHECK: return
+    mir! {
+        {
+            let a = Discriminant(i);
+            match a {
+                0 => bb1,
+                127 => bb2,
+                128 => bb3,
+                255 => bb4,
+                _ => unreachable_bb,
+            }
+        }
+        bb1 = {
+            RET = 0;
+            Goto(ret)
+        }
+        bb2 = {
+            RET = 127;
+            Goto(ret)
+        }
+        bb3 = {
+            RET = -128;
+            Goto(ret)
+        }
+        bb4 = {
+            RET = -1;
+            RET = -1;
+            Goto(ret)
+        }
+        unreachable_bb = {
+            Unreachable()
+        }
+        ret = {
+            Return()
+        }
+    }
+}
+
+// ## Cast with sext.
+
+// EMIT_MIR matches_reduce_branches.match_sext_i8_i16.MatchBranchSimplification.diff
+fn match_sext_i8_i16(i: EnumAi8) -> i16 {
+    // CHECK-LABEL: fn match_sext_i8_i16(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        EnumAi8::_128_0x80 => -128,
+        EnumAi8::_1_0xff => -1,
+        EnumAi8::o0_0x00 => 0,
+        EnumAi8::o1_0x01 => 1,
+        EnumAi8::o127_0x7f => 127,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_sext_i8_i16_failed.MatchBranchSimplification.diff
+// Converting `-1i8` to `255i16` is zext.
+fn match_sext_i8_i16_failed(i: EnumAi8) -> i16 {
+    // CHECK-LABEL: fn match_sext_i8_i16_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        EnumAi8::_128_0x80 => -128,
+        EnumAi8::_1_0xff => 255, // failed
+        EnumAi8::o0_0x00 => 0,
+        EnumAi8::o1_0x01 => 1,
+        EnumAi8::o127_0x7f => 127,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_sext_i8_u16.MatchBranchSimplification.diff
+fn match_sext_i8_u16(i: EnumAi8) -> u16 {
+    // CHECK-LABEL: fn match_sext_i8_u16(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        EnumAi8::_128_0x80 => 0xff80,
+        EnumAi8::_1_0xff => 0xffff,
+        EnumAi8::o0_0x00 => 0,
+        EnumAi8::o1_0x01 => 1,
+        EnumAi8::o127_0x7f => 127,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_sext_i8_u16_failed.MatchBranchSimplification.diff
+// Converting `-1i8` to `255u16` is zext.
+fn match_sext_i8_u16_failed(i: EnumAi8) -> u16 {
+    // CHECK-LABEL: fn match_sext_i8_u16_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        EnumAi8::_128_0x80 => 0xff80,
+        EnumAi8::_1_0xff => 0x00ff, // failed
+        EnumAi8::o0_0x00 => 0,
+        EnumAi8::o1_0x01 => 1,
+        EnumAi8::o127_0x7f => 127,
+    }
+}
+
+// ## Cast with zext.
+
+// EMIT_MIR matches_reduce_branches.match_zext_u8_u16.MatchBranchSimplification.diff
+fn match_zext_u8_u16(i: EnumAu8) -> u16 {
+    // CHECK-LABEL: fn match_zext_u8_u16(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 0x7f,
+        EnumAu8::u128_0x80 => 128,
+        EnumAu8::u255_0xff => 255,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_zext_u8_u16_failed.MatchBranchSimplification.diff
+fn match_zext_u8_u16_failed(i: EnumAu8) -> u16 {
+    // CHECK-LABEL: fn match_zext_u8_u16_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 0xff7f, // failed
+        EnumAu8::u128_0x80 => 128,
+        EnumAu8::u255_0xff => 255,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_zext_u8_i16.MatchBranchSimplification.diff
+fn match_zext_u8_i16(i: EnumAu8) -> i16 {
+    // CHECK-LABEL: fn match_zext_u8_i16(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => 127,
+        EnumAu8::u128_0x80 => 128,
+        EnumAu8::u255_0xff => 255,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_zext_u8_i16_failed.MatchBranchSimplification.diff
+fn match_zext_u8_i16_failed(i: EnumAu8) -> i16 {
+    // CHECK-LABEL: fn match_zext_u8_i16_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        EnumAu8::u0_0x00 => 0,
+        EnumAu8::u127_0x7f => -127, // failed
+        EnumAu8::u128_0x80 => 128,
+        EnumAu8::u255_0xff => 255,
+    }
+}
+
+// ## Cast with trunc.
+
+#[repr(u16)]
+enum EnumAu16 {
+    // 0x00nn
+    u0_0x0000 = 0,
+    u127_0x007f = 127,
+    u128_0x0080 = 128,
+    u255_0x00ff = 255,
+    // 0xffnn
+    u65280_0xff00 = 65280,
+    u65407_0xff7f = 65407,
+    u65408_0xff80 = 65408,
+    u65535_0xffff = 65535,
+}
+
 #[repr(i16)]
 enum EnumAi16 {
-    A = -1,
-    B = 2,
-    C = -3,
+    // 0x00nn
+    o128_0x0080 = 128,
+    o255_0x00ff = 255,
+    o0_0x0000 = 0,
+    o1_0x0001 = 1,
+    o127_0x007f = 127,
+    // 0xffnn
+    _128_0xff80 = -128,
+    _1_0xffff = -1,
+    o0_0xff00 = -256,
+    o1_0xff01 = -255,
+    o127_0xff7f = -129,
 }
 
-// EMIT_MIR matches_reduce_branches.match_i16_i8.MatchBranchSimplification.diff
-fn match_i16_i8(i: EnumAi16) -> i8 {
-    // CHECK-LABEL: fn match_i16_i8(
-    // CHECK: switchInt
+// EMIT_MIR matches_reduce_branches.match_trunc_i16_i8.MatchBranchSimplification.diff
+fn match_trunc_i16_i8(i: EnumAi16) -> i8 {
+    // CHECK-LABEL: fn match_trunc_i16_i8(
+    // CHECK-NOT: switchInt
+    // CHECK: return
     match i {
-        EnumAi16::A => -1,
-        EnumAi16::B => 2,
-        EnumAi16::C => -3,
+        // 0x00nn
+        EnumAi16::o128_0x0080 => -128,
+        EnumAi16::o255_0x00ff => -1,
+        EnumAi16::o0_0x0000 => 0,
+        EnumAi16::o1_0x0001 => 1,
+        EnumAi16::o127_0x007f => 127,
+        // 0xffnn
+        EnumAi16::_128_0xff80 => -128,
+        EnumAi16::_1_0xffff => -1,
+        EnumAi16::o0_0xff00 => 0,
+        EnumAi16::o1_0xff01 => 1,
+        EnumAi16::o127_0xff7f => 127,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_i16_i8_failed.MatchBranchSimplification.diff
+fn match_trunc_i16_i8_failed(i: EnumAi16) -> i8 {
+    // CHECK-LABEL: fn match_trunc_i16_i8_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAi16::o128_0x0080 => -128,
+        EnumAi16::o255_0x00ff => -1,
+        EnumAi16::o0_0x0000 => 0,
+        EnumAi16::o1_0x0001 => 1,
+        EnumAi16::o127_0x007f => 127,
+        // 0xffnn
+        EnumAi16::_128_0xff80 => -128,
+        EnumAi16::_1_0xffff => -1,
+        EnumAi16::o0_0xff00 => 0,
+        EnumAi16::o1_0xff01 => 1,
+        EnumAi16::o127_0xff7f => -127, // failed
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_i16_u8.MatchBranchSimplification.diff
+fn match_trunc_i16_u8(i: EnumAi16) -> u8 {
+    // CHECK-LABEL: fn match_trunc_i16_u8(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAi16::o128_0x0080 => 128,
+        EnumAi16::o255_0x00ff => 255,
+        EnumAi16::o0_0x0000 => 0,
+        EnumAi16::o1_0x0001 => 1,
+        EnumAi16::o127_0x007f => 127,
+        // 0xffnn
+        EnumAi16::_128_0xff80 => 128,
+        EnumAi16::_1_0xffff => 255,
+        EnumAi16::o0_0xff00 => 0,
+        EnumAi16::o1_0xff01 => 1,
+        EnumAi16::o127_0xff7f => 127,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_i16_u8_failed.MatchBranchSimplification.diff
+fn match_trunc_i16_u8_failed(i: EnumAi16) -> u8 {
+    // CHECK-LABEL: fn match_trunc_i16_u8_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAi16::o128_0x0080 => 128,
+        EnumAi16::o255_0x00ff => 255,
+        EnumAi16::o0_0x0000 => 0,
+        EnumAi16::o1_0x0001 => 1,
+        EnumAi16::o127_0x007f => 127,
+        // 0xffnn
+        EnumAi16::_128_0xff80 => 128,
+        EnumAi16::_1_0xffff => 255,
+        EnumAi16::o0_0xff00 => 0,
+        EnumAi16::o1_0xff01 => 1,
+        EnumAi16::o127_0xff7f => -127i8 as u8, // failed
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_u16_u8.MatchBranchSimplification.diff
+fn match_trunc_u16_u8(i: EnumAu16) -> u8 {
+    // CHECK-LABEL: fn match_trunc_u16_u8(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAu16::u0_0x0000 => 0,
+        EnumAu16::u127_0x007f => 127,
+        EnumAu16::u128_0x0080 => 128,
+        EnumAu16::u255_0x00ff => 255,
+        // 0xffnn
+        EnumAu16::u65280_0xff00 => 0,
+        EnumAu16::u65407_0xff7f => 127,
+        EnumAu16::u65408_0xff80 => 128,
+        EnumAu16::u65535_0xffff => 255,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_u16_u8_failed.MatchBranchSimplification.diff
+fn match_trunc_u16_u8_failed(i: EnumAu16) -> u8 {
+    // CHECK-LABEL: fn match_trunc_u16_u8_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAu16::u0_0x0000 => 0,
+        EnumAu16::u127_0x007f => 127,
+        EnumAu16::u128_0x0080 => 128,
+        EnumAu16::u255_0x00ff => 255,
+        // 0xffnn
+        EnumAu16::u65280_0xff00 => 0,
+        EnumAu16::u65407_0xff7f => 127,
+        EnumAu16::u65408_0xff80 => 128,
+        EnumAu16::u65535_0xffff => 127, // failed
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_u16_i8.MatchBranchSimplification.diff
+fn match_trunc_u16_i8(i: EnumAu16) -> i8 {
+    // CHECK-LABEL: fn match_trunc_u16_i8(
+    // CHECK-NOT: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAu16::u0_0x0000 => 0,
+        EnumAu16::u127_0x007f => 127,
+        EnumAu16::u128_0x0080 => -128,
+        EnumAu16::u255_0x00ff => -1,
+        // 0xffnn
+        EnumAu16::u65280_0xff00 => 0,
+        EnumAu16::u65407_0xff7f => 127,
+        EnumAu16::u65408_0xff80 => -128,
+        EnumAu16::u65535_0xffff => -1,
+    }
+}
+
+// EMIT_MIR matches_reduce_branches.match_trunc_u16_i8_failed.MatchBranchSimplification.diff
+fn match_trunc_u16_i8_failed(i: EnumAu16) -> i8 {
+    // CHECK-LABEL: fn match_trunc_u16_i8_failed(
+    // CHECK: switchInt
+    // CHECK: return
+    match i {
+        // 0x00nn
+        EnumAu16::u0_0x0000 => 0,
+        EnumAu16::u127_0x007f => 127,
+        EnumAu16::u128_0x0080 => -128,
+        EnumAu16::u255_0x00ff => -1,
+        // 0xffnn
+        EnumAu16::u65280_0xff00 => 0,
+        EnumAu16::u65407_0xff7f => 127,
+        EnumAu16::u65408_0xff80 => -128,
+        EnumAu16::u65535_0xffff => 1,
     }
 }
 
@@ -248,7 +606,8 @@ enum EnumAi128 {
 // EMIT_MIR matches_reduce_branches.match_i128_u128.MatchBranchSimplification.diff
 fn match_i128_u128(i: EnumAi128) -> u128 {
     // CHECK-LABEL: fn match_i128_u128(
-    // CHECK: switchInt
+    // CHECK-NOT: switchInt
+    // CHECK: return
     match i {
         EnumAi128::A => 1,
         EnumAi128::B => 2,
@@ -262,15 +621,34 @@ fn main() {
     let _ = foo(Some(()));
     let _ = bar(0);
     let _ = match_nested_if();
-    let _ = match_u8_i16(EnumAu8::A);
-    let _ = match_u8_i16_2(EnumAu8::A);
-    let _ = match_u8_i16_failed(EnumAu8::A);
-    let _ = match_u8_i16_fallback(1);
-    let _ = match_u8_u16(EnumBu8::A);
-    let _ = match_u8_u16_2(EnumBu8::A);
-    let _ = match_i8_i16(EnumAi8::A);
-    let _ = match_i8_i16_failed(EnumAi8::A);
-    let _ = match_i8_i16(EnumAi8::A);
-    let _ = match_i16_i8(EnumAi16::A);
+
+    let _: i8 = match_u8_i8(EnumAu8::u0_0x00);
+    let _: i8 = match_u8_i8_failed(EnumAu8::u0_0x00);
+    let _: (i8, i8) = match_u8_i8_2(EnumAu8::u0_0x00);
+    let _: (i8, i8) = match_u8_i8_2_failed(EnumAu8::u0_0x00);
+    let _: i8 = match_u8_i8_fallback(EnumAu8::u0_0x00);
+    let _: i8 = match_u8_i8_failed_len_1(EnumAu8::u0_0x00);
+    let _: i8 = match_u8_i8_failed_len_2(EnumAu8::u0_0x00);
+
+    let _: i16 = match_sext_i8_i16(EnumAi8::o0_0x00);
+    let _: i16 = match_sext_i8_i16_failed(EnumAi8::o0_0x00);
+    let _: u16 = match_sext_i8_u16(EnumAi8::o0_0x00);
+    let _: u16 = match_sext_i8_u16_failed(EnumAi8::o0_0x00);
+
+    let _: u16 = match_zext_u8_u16(EnumAu8::u0_0x00);
+    let _: u16 = match_zext_u8_u16_failed(EnumAu8::u0_0x00);
+    let _: i16 = match_zext_u8_i16(EnumAu8::u0_0x00);
+    let _: i16 = match_zext_u8_i16_failed(EnumAu8::u0_0x00);
+
+    let _: i8 = match_trunc_i16_i8(EnumAi16::o0_0x0000);
+    let _: i8 = match_trunc_i16_i8_failed(EnumAi16::o0_0x0000);
+    let _: u8 = match_trunc_i16_u8(EnumAi16::o0_0x0000);
+    let _: u8 = match_trunc_i16_u8_failed(EnumAi16::o0_0x0000);
+
+    let _: i8 = match_trunc_u16_i8(EnumAu16::u0_0x0000);
+    let _: i8 = match_trunc_u16_i8_failed(EnumAu16::u0_0x0000);
+    let _: u8 = match_trunc_u16_u8(EnumAu16::u0_0x0000);
+    let _: u8 = match_trunc_u16_u8_failed(EnumAu16::u0_0x0000);
+
     let _ = match_i128_u128(EnumAi128::A);
 }
diff --git a/tests/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff b/tests/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff
index 157f9c98353..11a18f58e3a 100644
--- a/tests/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff
+++ b/tests/mir-opt/matches_u8.exhaustive_match.MatchBranchSimplification.diff
@@ -5,27 +5,32 @@
       debug e => _1;
       let mut _0: u8;
       let mut _2: isize;
++     let mut _3: isize;
   
       bb0: {
           _2 = discriminant(_1);
-          switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 1_u8;
-          goto -> bb4;
-      }
-  
-      bb3: {
-          _0 = const 0_u8;
-          goto -> bb4;
-      }
-  
-      bb4: {
+-         switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 1_u8;
+-         goto -> bb4;
+-     }
+- 
+-     bb3: {
+-         _0 = const 0_u8;
+-         goto -> bb4;
+-     }
+- 
+-     bb4: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as u8 (IntToInt);
++         StorageDead(_3);
           return;
       }
   }
diff --git a/tests/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff b/tests/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
index 19083771fd9..809badc41ba 100644
--- a/tests/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
+++ b/tests/mir-opt/matches_u8.exhaustive_match_i8.MatchBranchSimplification.diff
@@ -5,27 +5,32 @@
       debug e => _1;
       let mut _0: i8;
       let mut _2: isize;
++     let mut _3: isize;
   
       bb0: {
           _2 = discriminant(_1);
-          switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
-      }
-  
-      bb1: {
-          unreachable;
-      }
-  
-      bb2: {
-          _0 = const 1_i8;
-          goto -> bb4;
-      }
-  
-      bb3: {
-          _0 = const 0_i8;
-          goto -> bb4;
-      }
-  
-      bb4: {
+-         switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
+-     }
+- 
+-     bb1: {
+-         unreachable;
+-     }
+- 
+-     bb2: {
+-         _0 = const 1_i8;
+-         goto -> bb4;
+-     }
+- 
+-     bb3: {
+-         _0 = const 0_i8;
+-         goto -> bb4;
+-     }
+- 
+-     bb4: {
++         StorageLive(_3);
++         _3 = move _2;
++         _0 = _3 as i8 (IntToInt);
++         StorageDead(_3);
           return;
       }
   }
diff --git a/tests/run-make/issue-36710/foo.cpp b/tests/run-make/cpp-global-destructors/foo.cpp
similarity index 100%
rename from tests/run-make/issue-36710/foo.cpp
rename to tests/run-make/cpp-global-destructors/foo.cpp
diff --git a/tests/run-make/issue-36710/foo.rs b/tests/run-make/cpp-global-destructors/foo.rs
similarity index 100%
rename from tests/run-make/issue-36710/foo.rs
rename to tests/run-make/cpp-global-destructors/foo.rs
diff --git a/tests/run-make/cpp-global-destructors/rmake.rs b/tests/run-make/cpp-global-destructors/rmake.rs
new file mode 100644
index 00000000000..9bc5c84e10d
--- /dev/null
+++ b/tests/run-make/cpp-global-destructors/rmake.rs
@@ -0,0 +1,26 @@
+// Some start files were missed when originally writing the logic to swap in musl start files.
+// This caused #36710. After the fix in #50105, this test checks that linking to C++ code
+// with global destructors works.
+// See https://github.com/rust-lang/rust/pull/50105
+
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+//@ ignore-none
+// Reason: no-std is not supported.
+//@ ignore-wasm32
+//@ ignore-wasm64
+// Reason: compiling C++ to WASM may cause problems.
+
+// Neither of these are tested in full CI.
+//@ ignore-nvptx64-nvidia-cuda
+// Reason: can't find crate "std"
+//@ ignore-sgx
+
+use run_make_support::{build_native_static_lib_cxx, run, rustc};
+
+fn main() {
+    build_native_static_lib_cxx("foo");
+    rustc().input("foo.rs").arg("-lfoo").extra_rs_cxx_flags().run();
+    run("foo");
+}
diff --git a/tests/run-make/cross-lang-lto-clang/Makefile b/tests/run-make/cross-lang-lto-clang/Makefile
deleted file mode 100644
index acf49c8f5c8..00000000000
--- a/tests/run-make/cross-lang-lto-clang/Makefile
+++ /dev/null
@@ -1,25 +0,0 @@
-# needs-force-clang-based-tests
-
-# This test makes sure that cross-language inlining actually works by checking
-# the generated machine code.
-
-include ../tools.mk
-
-all: cpp-executable rust-executable
-
-cpp-executable:
-	$(RUSTC) -Clinker-plugin-lto=on -o $(TMPDIR)/librustlib-xlto.a -Copt-level=2 -Ccodegen-units=1 ./rustlib.rs
-	$(CLANG) -flto=thin -fuse-ld=lld -L $(TMPDIR) -lrustlib-xlto -o $(TMPDIR)/cmain ./cmain.c -O3
-	# Make sure we don't find a call instruction to the function we expect to
-	# always be inlined.
-	"$(LLVM_BIN_DIR)"/llvm-objdump -d $(TMPDIR)/cmain | $(CGREP) -v -e "call.*rust_always_inlined"
-	# As a sanity check, make sure we do find a call instruction to a
-	# non-inlined function
-	"$(LLVM_BIN_DIR)"/llvm-objdump -d $(TMPDIR)/cmain | $(CGREP) -e "call.*rust_never_inlined"
-
-rust-executable:
-	$(CLANG) ./clib.c -flto=thin -c -o $(TMPDIR)/clib.o -O2
-	(cd $(TMPDIR); $(AR) crus ./libxyz.a ./clib.o)
-	$(RUSTC) -Clinker-plugin-lto=on -L$(TMPDIR) -Copt-level=2 -Clinker=$(CLANG) -Clink-arg=-fuse-ld=lld ./main.rs -o $(TMPDIR)/rsmain
-	"$(LLVM_BIN_DIR)"/llvm-objdump -d $(TMPDIR)/rsmain | $(CGREP) -e "call.*c_never_inlined"
-	"$(LLVM_BIN_DIR)"/llvm-objdump -d $(TMPDIR)/rsmain | $(CGREP) -v -e "call.*c_always_inlined"
diff --git a/tests/run-make/cross-lang-lto-clang/rmake.rs b/tests/run-make/cross-lang-lto-clang/rmake.rs
new file mode 100644
index 00000000000..1b15a54aacb
--- /dev/null
+++ b/tests/run-make/cross-lang-lto-clang/rmake.rs
@@ -0,0 +1,62 @@
+// This test checks that cross-language inlining actually works by checking
+// the generated machine code.
+// See https://github.com/rust-lang/rust/pull/57514
+
+//@ needs-force-clang-based-tests
+// NOTE(#126180): This test only runs on `x86_64-gnu-debug`, because that CI job sets
+// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
+// name.
+
+use run_make_support::{clang, env_var, llvm_ar, llvm_objdump, rustc, static_lib_name};
+
+fn main() {
+    rustc()
+        .linker_plugin_lto("on")
+        .output(static_lib_name("rustlib-xlto"))
+        .opt_level("2")
+        .codegen_units(1)
+        .input("rustlib.rs")
+        .run();
+    clang()
+        .lto("thin")
+        .use_ld("lld")
+        .arg("-lrustlib-xlto")
+        .out_exe("cmain")
+        .input("cmain.c")
+        .arg("-O3")
+        .run();
+    // Make sure we don't find a call instruction to the function we expect to
+    // always be inlined.
+    llvm_objdump()
+        .disassemble()
+        .input("cmain")
+        .run()
+        .assert_stdout_not_contains_regex("call.*rust_always_inlined");
+    // As a sanity check, make sure we do find a call instruction to a
+    // non-inlined function
+    llvm_objdump()
+        .disassemble()
+        .input("cmain")
+        .run()
+        .assert_stdout_contains_regex("call.*rust_never_inlined");
+    clang().input("clib.c").lto("thin").arg("-c").out_exe("clib.o").arg("-O2").run();
+    llvm_ar().obj_to_ar().output_input(static_lib_name("xyz"), "clib.o").run();
+    rustc()
+        .linker_plugin_lto("on")
+        .opt_level("2")
+        .linker(&env_var("CLANG"))
+        .link_arg("-fuse-ld=lld")
+        .input("main.rs")
+        .output("rsmain")
+        .run();
+    llvm_objdump()
+        .disassemble()
+        .input("rsmain")
+        .run()
+        .assert_stdout_not_contains_regex("call.*c_always_inlined");
+    llvm_objdump()
+        .disassemble()
+        .input("rsmain")
+        .run()
+        .assert_stdout_contains_regex("call.*c_never_inlined");
+}
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest/clib.c b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/clib.c
similarity index 100%
rename from tests/run-make/cross-lang-lto-pgo-smoketest/clib.c
rename to tests/run-make/cross-lang-lto-pgo-smoketest-clang/clib.c
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest/cmain.c b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/cmain.c
similarity index 100%
rename from tests/run-make/cross-lang-lto-pgo-smoketest/cmain.c
rename to tests/run-make/cross-lang-lto-pgo-smoketest-clang/cmain.c
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest/main.rs b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/main.rs
similarity index 100%
rename from tests/run-make/cross-lang-lto-pgo-smoketest/main.rs
rename to tests/run-make/cross-lang-lto-pgo-smoketest-clang/main.rs
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest-clang/rmake.rs b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/rmake.rs
new file mode 100644
index 00000000000..03c9af4bb89
--- /dev/null
+++ b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/rmake.rs
@@ -0,0 +1,120 @@
+// This test makes sure that cross-language inlining can be used in conjunction
+// with profile-guided optimization. The test only tests that the whole workflow
+// can be executed without anything crashing. It does not test whether PGO or
+// xLTO have any specific effect on the generated code.
+// See https://github.com/rust-lang/rust/pull/61036
+
+//@ needs-force-clang-based-tests
+// NOTE(#126180): This test would only run on `x86_64-gnu-debug`, because that CI job sets
+// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
+// name.
+
+//@ needs-profiler-support
+// FIXME(Oneirical): Except that due to the reliance on llvm-profdata, this test
+// never runs, because `x86_64-gnu-debug` does not have the `profiler_builtins` crate.
+
+//FIXME(Oneirical): There was a strange workaround for MSVC on this test
+// which added -C panic=abort to every RUSTC call. It was justified as follows:
+
+// "LLVM doesn't support instrumenting binaries that use SEH:
+// https://bugs.llvm.org/show_bug.cgi?id=41279
+// Things work fine with -Cpanic=abort though."
+
+// This isn't very pertinent, however, as the test does not get run on any
+// MSVC platforms.
+
+use run_make_support::{
+    clang, env_var, has_extension, has_prefix, llvm_ar, llvm_profdata, rfs, run, rustc,
+    shallow_find_files, static_lib_name,
+};
+
+fn main() {
+    rustc()
+        .linker_plugin_lto("on")
+        .output(static_lib_name("rustlib-xlto"))
+        .opt_level("3")
+        .codegen_units(1)
+        .input("rustlib.rs")
+        .arg("-Cprofile-generate=cpp-profdata")
+        .run();
+    clang()
+        .lto("thin")
+        .arg("-fprofile-generate=cpp-profdata")
+        .use_ld("lld")
+        .arg("-lrustlib-xlto")
+        .out_exe("cmain")
+        .input("cmain.c")
+        .arg("-O3")
+        .run();
+    run("cmain");
+    // Postprocess the profiling data so it can be used by the compiler
+    let profraw_files = shallow_find_files("cpp-profdata", |path| {
+        has_prefix(path, "default") && has_extension(path, "profraw")
+    });
+    let profraw_file = profraw_files.get(0).unwrap();
+    llvm_profdata().merge().output("cpp-profdata/merged.profdata").input(profraw_file).run();
+    rustc()
+        .linker_plugin_lto("on")
+        .profile_use("cpp-profdata/merged.profdata")
+        .output(static_lib_name("rustlib-xlto"))
+        .opt_level("3")
+        .codegen_units(1)
+        .input("rustlib.rs")
+        .run();
+    clang()
+        .lto("thin")
+        .arg("-fprofile-use=cpp-profdata/merged.profdata")
+        .use_ld("lld")
+        .arg("-lrustlib-xlto")
+        .out_exe("cmain")
+        .input("cmain.c")
+        .arg("-O3")
+        .run();
+
+    clang()
+        .input("clib.c")
+        .arg("-fprofile-generate=rs-profdata")
+        .lto("thin")
+        .arg("-c")
+        .out_exe("clib.o")
+        .arg("-O3")
+        .run();
+    llvm_ar().obj_to_ar().output_input(static_lib_name("xyz"), "clib.o").run();
+    rustc()
+        .linker_plugin_lto("on")
+        .opt_level("3")
+        .codegen_units(1)
+        .arg("-Cprofile-generate=rs-profdata")
+        .linker(&env_var("CLANG"))
+        .link_arg("-fuse-ld=lld")
+        .input("main.rs")
+        .output("rsmain")
+        .run();
+    run("rsmain");
+    // Postprocess the profiling data so it can be used by the compiler
+    let profraw_files = shallow_find_files("rs-profdata", |path| {
+        has_prefix(path, "default") && has_extension(path, "profraw")
+    });
+    let profraw_file = profraw_files.get(0).unwrap();
+    llvm_profdata().merge().output("rs-profdata/merged.profdata").input(profraw_file).run();
+    clang()
+        .input("clib.c")
+        .arg("-fprofile-use=rs-profdata/merged.profdata")
+        .arg("-c")
+        .lto("thin")
+        .out_exe("clib.o")
+        .arg("-O3")
+        .run();
+    rfs::remove_file(static_lib_name("xyz"));
+    llvm_ar().obj_to_ar().output_input(static_lib_name("xyz"), "clib.o").run();
+    rustc()
+        .linker_plugin_lto("on")
+        .opt_level("3")
+        .codegen_units(1)
+        .arg("-Cprofile-use=rs-profdata/merged.profdata")
+        .linker(&env_var("CLANG"))
+        .link_arg("-fuse-ld=lld")
+        .input("main.rs")
+        .output("rsmain")
+        .run();
+}
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest/rustlib.rs b/tests/run-make/cross-lang-lto-pgo-smoketest-clang/rustlib.rs
similarity index 100%
rename from tests/run-make/cross-lang-lto-pgo-smoketest/rustlib.rs
rename to tests/run-make/cross-lang-lto-pgo-smoketest-clang/rustlib.rs
diff --git a/tests/run-make/cross-lang-lto-pgo-smoketest/Makefile b/tests/run-make/cross-lang-lto-pgo-smoketest/Makefile
deleted file mode 100644
index 738e23f9c66..00000000000
--- a/tests/run-make/cross-lang-lto-pgo-smoketest/Makefile
+++ /dev/null
@@ -1,90 +0,0 @@
-# needs-force-clang-based-tests
-
-# FIXME(#126180): This test doesn't actually run anywhere, because the only
-# CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
-
-# This test makes sure that cross-language inlining can be used in conjunction
-# with profile-guided optimization. The test only tests that the whole workflow
-# can be executed without anything crashing. It does not test whether PGO or
-# xLTO have any specific effect on the generated code.
-
-include ../tools.mk
-
-COMMON_FLAGS=-Copt-level=3 -Ccodegen-units=1
-
-# LLVM doesn't support instrumenting binaries that use SEH:
-# https://bugs.llvm.org/show_bug.cgi?id=41279
-#
-# Things work fine with -Cpanic=abort though.
-ifdef IS_MSVC
-COMMON_FLAGS+= -Cpanic=abort
-endif
-
-all: cpp-executable rust-executable
-
-cpp-executable:
-	$(RUSTC) -Clinker-plugin-lto=on \
-	         -Cprofile-generate="$(TMPDIR)"/cpp-profdata \
-	         -o "$(TMPDIR)"/librustlib-xlto.a \
-	         $(COMMON_FLAGS) \
-	         ./rustlib.rs
-	$(CLANG) -flto=thin \
-	         -fprofile-generate="$(TMPDIR)"/cpp-profdata \
-	         -fuse-ld=lld \
-	         -L "$(TMPDIR)" \
-	         -lrustlib-xlto \
-	         -o "$(TMPDIR)"/cmain \
-	         -O3 \
-	         ./cmain.c
-	$(TMPDIR)/cmain
-	# Postprocess the profiling data so it can be used by the compiler
-	"$(LLVM_BIN_DIR)"/llvm-profdata merge \
-		-o "$(TMPDIR)"/cpp-profdata/merged.profdata \
-		"$(TMPDIR)"/cpp-profdata/default_*.profraw
-	$(RUSTC) -Clinker-plugin-lto=on \
-	         -Cprofile-use="$(TMPDIR)"/cpp-profdata/merged.profdata \
-	         -o "$(TMPDIR)"/librustlib-xlto.a \
-	         $(COMMON_FLAGS) \
-	         ./rustlib.rs
-	$(CLANG) -flto=thin \
-	         -fprofile-use="$(TMPDIR)"/cpp-profdata/merged.profdata \
-	         -fuse-ld=lld \
-	         -L "$(TMPDIR)" \
-	         -lrustlib-xlto \
-	         -o "$(TMPDIR)"/cmain \
-	         -O3 \
-	         ./cmain.c
-
-rust-executable:
-	exit
-	$(CLANG) ./clib.c -fprofile-generate="$(TMPDIR)"/rs-profdata -flto=thin -c -o $(TMPDIR)/clib.o -O3
-	(cd $(TMPDIR); $(AR) crus ./libxyz.a ./clib.o)
-	$(RUSTC) -Clinker-plugin-lto=on \
-	         -Cprofile-generate="$(TMPDIR)"/rs-profdata \
-	         -L$(TMPDIR) \
-	         $(COMMON_FLAGS) \
-	         -Clinker=$(CLANG) \
-	         -Clink-arg=-fuse-ld=lld \
-	         -o $(TMPDIR)/rsmain \
-	         ./main.rs
-	$(TMPDIR)/rsmain
-	# Postprocess the profiling data so it can be used by the compiler
-	"$(LLVM_BIN_DIR)"/llvm-profdata merge \
-		-o "$(TMPDIR)"/rs-profdata/merged.profdata \
-		"$(TMPDIR)"/rs-profdata/default_*.profraw
-	$(CLANG) ./clib.c \
-	         -fprofile-use="$(TMPDIR)"/rs-profdata/merged.profdata \
-	         -flto=thin \
-	         -c \
-	         -o $(TMPDIR)/clib.o \
-	         -O3
-	rm "$(TMPDIR)"/libxyz.a
-	(cd $(TMPDIR); $(AR) crus ./libxyz.a ./clib.o)
-	$(RUSTC) -Clinker-plugin-lto=on \
-	         -Cprofile-use="$(TMPDIR)"/rs-profdata/merged.profdata \
-	         -L$(TMPDIR) \
-	         $(COMMON_FLAGS) \
-	         -Clinker=$(CLANG) \
-	         -Clink-arg=-fuse-ld=lld \
-	         -o $(TMPDIR)/rsmain \
-	         ./main.rs
diff --git a/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs b/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
index 391759ec5f6..92573353a74 100644
--- a/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
+++ b/tests/run-make/cross-lang-lto-riscv-abi/rmake.rs
@@ -3,8 +3,11 @@
 //@ needs-force-clang-based-tests
 //@ needs-llvm-components riscv
 
-// FIXME(#126180): This test doesn't actually run anywhere, because the only
-// CI job that sets RUSTBUILD_FORCE_CLANG_BASED_TESTS runs very few tests.
+//@ needs-force-clang-based-tests
+// FIXME(#126180): This test can only run on `x86_64-gnu-debug`, because that CI job sets
+// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
+// name.
+// However, this test does not run at all as its name does not contain "clang".
 
 use std::path::PathBuf;
 use std::process::{Command, Output};
diff --git a/tests/run-make/cross-lang-lto/Makefile b/tests/run-make/cross-lang-lto/Makefile
deleted file mode 100644
index 92058f952a9..00000000000
--- a/tests/run-make/cross-lang-lto/Makefile
+++ /dev/null
@@ -1,57 +0,0 @@
-
-include ../tools.mk
-
-# ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
-# (so fixing it is harder). See #57765 for context
-ifndef IS_WINDOWS
-
-# This test makes sure that the object files we generate are actually
-# LLVM bitcode files (as used by linker LTO plugins) when compiling with
-# -Clinker-plugin-lto.
-
-# this only succeeds for bitcode files
-ASSERT_IS_BITCODE_OBJ=("$(LLVM_BIN_DIR)"/llvm-bcanalyzer $(1))
-EXTRACT_OBJS=(cd $(TMPDIR); rm -f ./*.o; "$(LLVM_BIN_DIR)"/llvm-ar x $(1))
-
-BUILD_LIB=$(RUSTC) lib.rs -Copt-level=2 -Clinker-plugin-lto -Ccodegen-units=1
-BUILD_EXE=$(RUSTC) main.rs -Copt-level=2 -Clinker-plugin-lto -Ccodegen-units=1 --emit=obj
-
-all: staticlib staticlib-fat-lto staticlib-thin-lto rlib exe cdylib rdylib
-
-staticlib: lib.rs
-	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib.a
-	$(call EXTRACT_OBJS, liblib.a)
-	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
-
-staticlib-fat-lto: lib.rs
-	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-fat-lto.a -Clto=fat
-	$(call EXTRACT_OBJS, liblib-fat-lto.a)
-	for file in $(TMPDIR)/liblib-fat-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
-
-staticlib-thin-lto: lib.rs
-	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-thin-lto.a -Clto=thin
-	$(call EXTRACT_OBJS, liblib-thin-lto.a)
-	for file in $(TMPDIR)/liblib-thin-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
-
-rlib: lib.rs
-	$(BUILD_LIB) --crate-type=rlib -o $(TMPDIR)/liblib.rlib
-	$(call EXTRACT_OBJS, liblib.rlib)
-	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
-
-cdylib: lib.rs
-	$(BUILD_LIB) --crate-type=cdylib --emit=obj -o $(TMPDIR)/cdylib.o
-	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/cdylib.o)
-
-rdylib: lib.rs
-	$(BUILD_LIB) --crate-type=dylib --emit=obj -o $(TMPDIR)/rdylib.o
-	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/rdylib.o)
-
-exe: lib.rs
-	$(BUILD_EXE) -o $(TMPDIR)/exe.o
-	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/exe.o)
-
-else
-
-all:
-
-endif
diff --git a/tests/run-make/cross-lang-lto/rmake.rs b/tests/run-make/cross-lang-lto/rmake.rs
new file mode 100644
index 00000000000..dc376b561e4
--- /dev/null
+++ b/tests/run-make/cross-lang-lto/rmake.rs
@@ -0,0 +1,110 @@
+// This test checks that the object files we generate are actually
+// LLVM bitcode files (as used by linker LTO plugins) when compiling with
+// -Clinker-plugin-lto.
+// See https://github.com/rust-lang/rust/pull/50000
+
+#![feature(path_file_prefix)]
+
+use std::path::PathBuf;
+
+use run_make_support::{
+    cwd, has_extension, has_prefix, llvm_ar, llvm_bcanalyzer, path, rfs, rust_lib_name, rustc,
+    shallow_find_files, static_lib_name,
+};
+
+fn main() {
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib")),
+        lto: None,
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib-fat-lto")),
+        lto: Some("fat"),
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("staticlib"),
+        output: path(static_lib_name("liblib-thin-lto")),
+        lto: Some("thin"),
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("rlib"),
+        output: path(rust_lib_name("liblib")),
+        lto: None,
+        emit_obj: false,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("cdylib"),
+        output: path("cdylib.o"),
+        lto: None,
+        emit_obj: true,
+    });
+    check_bitcode(LibBuild {
+        source: path("lib.rs"),
+        crate_type: Some("dylib"),
+        output: path("rdylib.o"),
+        lto: None,
+        emit_obj: true,
+    });
+    check_bitcode(LibBuild {
+        source: path("main.rs"),
+        crate_type: None,
+        output: path("exe.o"),
+        lto: None,
+        emit_obj: true,
+    });
+}
+
+#[track_caller]
+fn check_bitcode(instructions: LibBuild) {
+    let mut rustc = rustc();
+    rustc
+        .input(instructions.source)
+        .output(&instructions.output)
+        .opt_level("2")
+        .codegen_units(1)
+        .arg("-Clinker-plugin-lto");
+    if instructions.emit_obj {
+        rustc.emit("obj");
+    }
+    if let Some(crate_type) = instructions.crate_type {
+        rustc.crate_type(crate_type);
+    }
+    if let Some(lto) = instructions.lto {
+        rustc.arg(format!("-Clto={lto}"));
+    }
+    rustc.run();
+
+    if instructions.output.extension().unwrap() != "o" {
+        // Remove all potential leftover object files, then turn the output into an object file.
+        for object in shallow_find_files(cwd(), |path| has_extension(path, "o")) {
+            rfs::remove_file(object);
+        }
+        llvm_ar().extract().arg(&instructions.output).run();
+    }
+
+    for object in shallow_find_files(cwd(), |path| {
+        has_prefix(path, instructions.output.file_prefix().unwrap().to_str().unwrap())
+            && has_extension(path, "o")
+    }) {
+        // All generated object files should be LLVM bitcode files - this will fail otherwise.
+        llvm_bcanalyzer().input(object).run();
+    }
+}
+
+struct LibBuild {
+    source: PathBuf,
+    crate_type: Option<&'static str>,
+    output: PathBuf,
+    lto: Option<&'static str>,
+    emit_obj: bool,
+}
diff --git a/tests/run-make/foreign-double-unwind/Makefile b/tests/run-make/foreign-double-unwind/Makefile
deleted file mode 100644
index b5e52808d2f..00000000000
--- a/tests/run-make/foreign-double-unwind/Makefile
+++ /dev/null
@@ -1,12 +0,0 @@
-# ignore-cross-compile
-# needs-unwind
-include ../tools.mk
-
-all: foo
-	$(call RUN,foo) | $(CGREP) -v unreachable
-
-foo: foo.rs $(call NATIVE_STATICLIB,foo)
-	$(RUSTC) $< -lfoo $(EXTRARSCXXFLAGS)
-
-$(TMPDIR)/libfoo.o: foo.cpp
-	$(call COMPILE_OBJ_CXX,$@,$<)
diff --git a/tests/run-make/foreign-double-unwind/rmake.rs b/tests/run-make/foreign-double-unwind/rmake.rs
new file mode 100644
index 00000000000..9bd3b4c0fea
--- /dev/null
+++ b/tests/run-make/foreign-double-unwind/rmake.rs
@@ -0,0 +1,21 @@
+// When using foreign function interface (FFI) with C++, it is possible
+// to run into a "double unwind" if either both Rust and C++ run into a panic
+// and exception at the same time, or C++ encounters two exceptions. In this case,
+// one of the panic unwinds would be leaked and the other would be kept, leading
+// to undefined behaviour. After this was fixed in #92911, this test checks that
+// the keyword "unreachable" indicative of this bug triggering in this specific context
+// does not appear after successfully compiling and executing the program.
+// See https://github.com/rust-lang/rust/pull/92911
+
+//@ needs-unwind
+// Reason: this test exercises panic unwinding
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+use run_make_support::{build_native_static_lib_cxx, run_fail, rustc};
+
+fn main() {
+    build_native_static_lib_cxx("foo");
+    rustc().input("foo.rs").arg("-lfoo").extra_rs_cxx_flags().run();
+    run_fail("foo").assert_stdout_not_contains("unreachable");
+}
diff --git a/tests/run-make/foreign-exceptions/Makefile b/tests/run-make/foreign-exceptions/Makefile
deleted file mode 100644
index 56c41b274fb..00000000000
--- a/tests/run-make/foreign-exceptions/Makefile
+++ /dev/null
@@ -1,12 +0,0 @@
-# ignore-cross-compile
-# needs-unwind
-include ../tools.mk
-
-all: foo
-	$(call RUN,foo)
-
-foo: foo.rs $(call NATIVE_STATICLIB,foo)
-	$(RUSTC) $< -lfoo $(EXTRARSCXXFLAGS)
-
-$(TMPDIR)/libfoo.o: foo.cpp
-	$(call COMPILE_OBJ_CXX,$@,$<)
diff --git a/tests/run-make/foreign-exceptions/rmake.rs b/tests/run-make/foreign-exceptions/rmake.rs
new file mode 100644
index 00000000000..929319f049f
--- /dev/null
+++ b/tests/run-make/foreign-exceptions/rmake.rs
@@ -0,0 +1,19 @@
+// This test was created to check that compilation and execution still works
+// after the addition of a new feature, in #65646: the ability to unwind panics
+// and exceptions back and forth between Rust and C++. This is a basic smoke test,
+// this feature being broken in quiet or subtle ways could still result in this test
+// passing.
+// See https://github.com/rust-lang/rust/pull/65646
+
+//@ needs-unwind
+// Reason: this test exercises panic unwinding
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+use run_make_support::{build_native_static_lib_cxx, run, rustc};
+
+fn main() {
+    build_native_static_lib_cxx("foo");
+    rustc().input("foo.rs").arg("-lfoo").extra_rs_cxx_flags().run();
+    run("foo");
+}
diff --git a/tests/run-make/issue-36710/Makefile b/tests/run-make/issue-36710/Makefile
deleted file mode 100644
index 7b91107a234..00000000000
--- a/tests/run-make/issue-36710/Makefile
+++ /dev/null
@@ -1,19 +0,0 @@
-# ignore-cross-compile
-# ignore-none no-std is not supported
-# ignore-wasm32 FIXME: don't attempt to compile C++ to WASM
-# ignore-wasm64 FIXME: don't attempt to compile C++ to WASM
-# ignore-nvptx64-nvidia-cuda FIXME: can't find crate for `std`
-# ignore-musl FIXME: this makefile needs teaching how to use a musl toolchain
-#                    (see dist-i586-gnu-i586-i686-musl Dockerfile)
-# ignore-sgx
-
-include ../tools.mk
-
-all: foo
-	$(call RUN,foo)
-
-foo: foo.rs $(call NATIVE_STATICLIB,foo)
-	$(RUSTC) $< -lfoo $(EXTRARSCXXFLAGS) --target $(TARGET)
-
-$(TMPDIR)/libfoo.o: foo.cpp
-	$(call COMPILE_OBJ_CXX,$@,$<)
diff --git a/tests/run-make/issue-88756-default-output/Makefile b/tests/run-make/issue-88756-default-output/Makefile
deleted file mode 100644
index d1c3d0fe082..00000000000
--- a/tests/run-make/issue-88756-default-output/Makefile
+++ /dev/null
@@ -1,4 +0,0 @@
-include ../tools.mk
-
-all:
-	$(BARE_RUSTDOC) 2>&1 | sed -E 's@/nightly/|/beta/|/stable/|/1\.[0-9]+\.[0-9]+/@/$$CHANNEL/@g' | diff - output-default.stdout
diff --git a/tests/run-make/issue-88756-default-output/README.md b/tests/run-make/issue-88756-default-output/README.md
deleted file mode 100644
index 8cbfac4f7d2..00000000000
--- a/tests/run-make/issue-88756-default-output/README.md
+++ /dev/null
@@ -1 +0,0 @@
-This is a test to verify that the default behavior of `rustdoc` is printing out help output instead of erroring out (#88756).
diff --git a/tests/run-make/issue-88756-default-output/x.rs b/tests/run-make/issue-88756-default-output/x.rs
deleted file mode 100644
index 5df7576133a..00000000000
--- a/tests/run-make/issue-88756-default-output/x.rs
+++ /dev/null
@@ -1 +0,0 @@
-// nothing to see here
diff --git a/tests/run-make/link-cfg/Makefile b/tests/run-make/link-cfg/Makefile
deleted file mode 100644
index a4099701144..00000000000
--- a/tests/run-make/link-cfg/Makefile
+++ /dev/null
@@ -1,23 +0,0 @@
-# ignore-cross-compile
-include ../tools.mk
-
-all: $(call DYLIB,return1) $(call DYLIB,return2) $(call NATIVE_STATICLIB,return3)
-	ls $(TMPDIR)
-	$(BARE_RUSTC) --print cfg --target x86_64-unknown-linux-musl | $(CGREP) crt-static
-
-	$(RUSTC) no-deps.rs --cfg foo
-	$(call RUN,no-deps)
-	$(RUSTC) no-deps.rs --cfg bar
-	$(call RUN,no-deps)
-
-	$(RUSTC) dep.rs
-	$(RUSTC) with-deps.rs --cfg foo
-	$(call RUN,with-deps)
-	$(RUSTC) with-deps.rs --cfg bar
-	$(call RUN,with-deps)
-
-	$(RUSTC) dep-with-staticlib.rs
-	$(RUSTC) with-staticlib-deps.rs --cfg foo
-	$(call RUN,with-staticlib-deps)
-	$(RUSTC) with-staticlib-deps.rs --cfg bar
-	$(call RUN,with-staticlib-deps)
diff --git a/tests/run-make/link-cfg/rmake.rs b/tests/run-make/link-cfg/rmake.rs
new file mode 100644
index 00000000000..732de5dbd0b
--- /dev/null
+++ b/tests/run-make/link-cfg/rmake.rs
@@ -0,0 +1,43 @@
+// The `#[link(cfg(..))]` annotation means that the `#[link]`
+// directive is only active in a compilation unit if that `cfg` value is satisfied.
+// For example, when compiling an rlib, these directives are just encoded and
+// ignored for dylibs, and all staticlibs are continued to be put into the rlib as
+// usual. When placing that rlib into a staticlib, executable, or dylib, however,
+// the `cfg` is evaluated *as if it were defined in the final artifact* and the
+// library is decided to be linked or not.
+// This test exercises this new feature by testing it with no dependencies, then
+// with only dynamic libraries, then with both a staticlib and dylibs. Compilation
+// and execution should be successful.
+// See https://github.com/rust-lang/rust/pull/37545
+
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+
+use run_make_support::{bare_rustc, build_native_dynamic_lib, build_native_static_lib, run, rustc};
+
+fn main() {
+    build_native_dynamic_lib("return1");
+    build_native_dynamic_lib("return2");
+    build_native_static_lib("return3");
+    bare_rustc()
+        .print("cfg")
+        .target("x86_64-unknown-linux-musl")
+        .run()
+        .assert_stdout_contains("crt-static");
+    rustc().input("no-deps.rs").cfg("foo").run();
+    run("no-deps");
+    rustc().input("no-deps.rs").cfg("bar").run();
+    run("no-deps");
+
+    rustc().input("dep.rs").run();
+    rustc().input("with-deps.rs").cfg("foo").run();
+    run("with-deps");
+    rustc().input("with-deps.rs").cfg("bar").run();
+    run("with-deps");
+
+    rustc().input("dep-with-staticlib.rs").run();
+    rustc().input("with-staticlib-deps.rs").cfg("foo").run();
+    run("with-staticlib-deps");
+    rustc().input("with-staticlib-deps.rs").cfg("bar").run();
+    run("with-staticlib-deps");
+}
diff --git a/tests/run-make/issue-88756-default-output/output-default.stdout b/tests/run-make/rustdoc-default-output/output-default.stdout
similarity index 100%
rename from tests/run-make/issue-88756-default-output/output-default.stdout
rename to tests/run-make/rustdoc-default-output/output-default.stdout
diff --git a/tests/run-make/rustdoc-default-output/rmake.rs b/tests/run-make/rustdoc-default-output/rmake.rs
new file mode 100644
index 00000000000..06720445a35
--- /dev/null
+++ b/tests/run-make/rustdoc-default-output/rmake.rs
@@ -0,0 +1,16 @@
+// Calling rustdoc with no arguments, which should bring up a help menu, used to
+// cause an error as rustdoc expects an input file. Fixed in #98331, this test
+// ensures the output of rustdoc's help menu is as expected.
+// See https://github.com/rust-lang/rust/issues/88756
+
+use run_make_support::{bare_rustdoc, diff};
+
+fn main() {
+    let out = bare_rustdoc().run().stdout_utf8();
+    diff()
+        .expected_file("output-default.stdout")
+        .actual_text("actual", out)
+        // replace the channel type in the URL with $CHANNEL
+        .normalize(r"nightly/|beta/|stable/|1\.[0-9]+\.[0-9]+/", "$$CHANNEL/")
+        .run();
+}
diff --git a/tests/run-make/used/rmake.rs b/tests/run-make/used/rmake.rs
index 56ef5c6b9cc..39f36b2eea8 100644
--- a/tests/run-make/used/rmake.rs
+++ b/tests/run-make/used/rmake.rs
@@ -4,12 +4,10 @@
 // It comes from #39987 which implements this RFC for the #[used] attribute:
 // https://rust-lang.github.io/rfcs/2386-used.html
 
-//@ ignore-msvc
-
-use run_make_support::{cmd, rustc};
+use run_make_support::rustc;
+use run_make_support::symbols::any_symbol_contains;
 
 fn main() {
     rustc().opt_level("3").emit("obj").input("used.rs").run();
-
-    cmd("nm").arg("used.o").run().assert_stdout_contains("FOO");
+    assert!(any_symbol_contains("used.o", &["FOO"]));
 }
diff --git a/tests/run-make/used/used.rs b/tests/run-make/used/used.rs
index dca0a5e1167..133f8121a8e 100644
--- a/tests/run-make/used/used.rs
+++ b/tests/run-make/used/used.rs
@@ -2,5 +2,3 @@
 
 #[used]
 static FOO: u32 = 0;
-
-static BAR: u32 = 0;
diff --git a/tests/run-make/wasm-override-linker/rmake.rs b/tests/run-make/wasm-override-linker/rmake.rs
index 01bc08e9901..b04edc18eef 100644
--- a/tests/run-make/wasm-override-linker/rmake.rs
+++ b/tests/run-make/wasm-override-linker/rmake.rs
@@ -2,6 +2,10 @@
 // $ RUSTBUILD_FORCE_CLANG_BASED_TESTS=1 ./x.py test tests/run-make/wasm-override-linker/
 
 //@ needs-force-clang-based-tests
+// FIXME(#126180): This test can only run on `x86_64-gnu-debug`, because that CI job sets
+// RUSTBUILD_FORCE_CLANG_BASED_TESTS and only runs tests which contain "clang" in their
+// name.
+// However, this test does not run at all as its name does not contain "clang".
 
 use run_make_support::{env_var, rustc, target};
 
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/q.rs b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/q.rs
new file mode 100644
index 00000000000..5d0881029cb
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/q.rs
@@ -0,0 +1,2 @@
+//@ build-aux-docs
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/t.rs b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/t.rs
new file mode 100644
index 00000000000..fab9ec4a92b
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/auxiliary/t.rs
@@ -0,0 +1,4 @@
+//@ aux-build:q.rs
+//@ build-aux-docs
+extern crate q;
+pub trait Tango {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/s.rs b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/s.rs
new file mode 100644
index 00000000000..85c460ace64
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive-no-index/s.rs
@@ -0,0 +1,16 @@
+//@ aux-build:t.rs
+//@ build-aux-docs
+//@ has q/struct.Quebec.html
+//@ has s/struct.Sierra.html
+//@ has t/trait.Tango.html
+//@ hasraw s/struct.Sierra.html 'Tango'
+//@ hasraw trait.impl/t/trait.Tango.js 'struct.Sierra.html'
+//@ hasraw search-index.js 'Tango'
+//@ hasraw search-index.js 'Sierra'
+//@ hasraw search-index.js 'Quebec'
+
+// We document multiple crates into the same output directory, which
+// merges the cross-crate information. Everything is available.
+extern crate t;
+pub struct Sierra;
+impl t::Tango for Sierra {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/q.rs b/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/q.rs
new file mode 100644
index 00000000000..932a0b17206
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/q.rs
@@ -0,0 +1,5 @@
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/t.rs b/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/t.rs
new file mode 100644
index 00000000000..c21a59c6518
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive/auxiliary/t.rs
@@ -0,0 +1,7 @@
+//@ aux-build:q.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+extern crate q;
+pub trait Tango {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-transitive/s.rs b/tests/rustdoc/cross-crate-info/cargo-transitive/s.rs
new file mode 100644
index 00000000000..68bfc34883b
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-transitive/s.rs
@@ -0,0 +1,24 @@
+//@ aux-build:t.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+//@ has index.html
+//@ has index.html '//h1' 'List of all crates'
+//@ has index.html '//ul[@class="all-items"]//a[@href="q/index.html"]' 'q'
+//@ has index.html '//ul[@class="all-items"]//a[@href="s/index.html"]' 's'
+//@ has index.html '//ul[@class="all-items"]//a[@href="t/index.html"]' 't'
+//@ has q/struct.Quebec.html
+//@ has s/struct.Sierra.html
+//@ has t/trait.Tango.html
+//@ hasraw s/struct.Sierra.html 'Tango'
+//@ hasraw trait.impl/t/trait.Tango.js 'struct.Sierra.html'
+//@ hasraw search-index.js 'Tango'
+//@ hasraw search-index.js 'Sierra'
+//@ hasraw search-index.js 'Quebec'
+
+// We document multiple crates into the same output directory, which
+// merges the cross-crate information. Everything is available.
+extern crate t;
+pub struct Sierra;
+impl t::Tango for Sierra {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-two-no-index/auxiliary/f.rs b/tests/rustdoc/cross-crate-info/cargo-two-no-index/auxiliary/f.rs
new file mode 100644
index 00000000000..abc580a388c
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-two-no-index/auxiliary/f.rs
@@ -0,0 +1,2 @@
+//@ build-aux-docs
+pub trait Foxtrot {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-two-no-index/e.rs b/tests/rustdoc/cross-crate-info/cargo-two-no-index/e.rs
new file mode 100644
index 00000000000..c93298f969e
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-two-no-index/e.rs
@@ -0,0 +1,14 @@
+//@ aux-build:f.rs
+//@ build-aux-docs
+//@ has e/enum.Echo.html
+//@ has f/trait.Foxtrot.html
+//@ hasraw e/enum.Echo.html 'Foxtrot'
+//@ hasraw trait.impl/f/trait.Foxtrot.js 'enum.Echo.html'
+//@ hasraw search-index.js 'Foxtrot'
+//@ hasraw search-index.js 'Echo'
+
+// document two crates in the same way that cargo does. do not provide
+// --enable-index-page
+extern crate f;
+pub enum Echo {}
+impl f::Foxtrot for Echo {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-two/auxiliary/f.rs b/tests/rustdoc/cross-crate-info/cargo-two/auxiliary/f.rs
new file mode 100644
index 00000000000..a2a7033b131
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-two/auxiliary/f.rs
@@ -0,0 +1,5 @@
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+pub trait Foxtrot {}
diff --git a/tests/rustdoc/cross-crate-info/cargo-two/e.rs b/tests/rustdoc/cross-crate-info/cargo-two/e.rs
new file mode 100644
index 00000000000..00f86cbc348
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/cargo-two/e.rs
@@ -0,0 +1,21 @@
+//@ aux-build:f.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+//@ has index.html
+//@ has index.html '//h1' 'List of all crates'
+//@ has index.html '//ul[@class="all-items"]//a[@href="f/index.html"]' 'f'
+//@ has index.html '//ul[@class="all-items"]//a[@href="e/index.html"]' 'e'
+//@ has e/enum.Echo.html
+//@ has f/trait.Foxtrot.html
+//@ hasraw e/enum.Echo.html 'Foxtrot'
+//@ hasraw trait.impl/f/trait.Foxtrot.js 'enum.Echo.html'
+//@ hasraw search-index.js 'Foxtrot'
+//@ hasraw search-index.js 'Echo'
+
+// document two crates in the same way that cargo does, writing them both
+// into the same output directory
+extern crate f;
+pub enum Echo {}
+impl f::Foxtrot for Echo {}
diff --git a/tests/rustdoc/cross-crate-info/index-on-last/auxiliary/f.rs b/tests/rustdoc/cross-crate-info/index-on-last/auxiliary/f.rs
new file mode 100644
index 00000000000..abc580a388c
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/index-on-last/auxiliary/f.rs
@@ -0,0 +1,2 @@
+//@ build-aux-docs
+pub trait Foxtrot {}
diff --git a/tests/rustdoc/cross-crate-info/index-on-last/e.rs b/tests/rustdoc/cross-crate-info/index-on-last/e.rs
new file mode 100644
index 00000000000..ffee898cd96
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/index-on-last/e.rs
@@ -0,0 +1,20 @@
+//@ aux-build:f.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+//@ has index.html
+//@ has index.html '//h1' 'List of all crates'
+//@ has index.html '//ul[@class="all-items"]//a[@href="f/index.html"]' 'f'
+//@ has index.html '//ul[@class="all-items"]//a[@href="e/index.html"]' 'e'
+//@ has e/enum.Echo.html
+//@ has f/trait.Foxtrot.html
+//@ hasraw e/enum.Echo.html 'Foxtrot'
+//@ hasraw trait.impl/f/trait.Foxtrot.js 'enum.Echo.html'
+//@ hasraw search-index.js 'Foxtrot'
+//@ hasraw search-index.js 'Echo'
+
+// only declare --enable-index-page to the last rustdoc invocation
+extern crate f;
+pub enum Echo {}
+impl f::Foxtrot for Echo {}
diff --git a/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/q.rs b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/q.rs
new file mode 100644
index 00000000000..932a0b17206
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/q.rs
@@ -0,0 +1,5 @@
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/r.rs b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/r.rs
new file mode 100644
index 00000000000..2c0db2abc53
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/r.rs
@@ -0,0 +1,7 @@
+//@ aux-build:s.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+extern crate s;
+pub type Romeo = s::Sierra;
diff --git a/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/s.rs b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/s.rs
new file mode 100644
index 00000000000..355d3f1aaa8
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/s.rs
@@ -0,0 +1,8 @@
+//@ aux-build:t.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+extern crate t;
+pub struct Sierra;
+impl t::Tango for Sierra {}
diff --git a/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/t.rs b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/t.rs
new file mode 100644
index 00000000000..c21a59c6518
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/kitchen-sink/auxiliary/t.rs
@@ -0,0 +1,7 @@
+//@ aux-build:q.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+extern crate q;
+pub trait Tango {}
diff --git a/tests/rustdoc/cross-crate-info/kitchen-sink/i.rs b/tests/rustdoc/cross-crate-info/kitchen-sink/i.rs
new file mode 100644
index 00000000000..bcb9464795a
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/kitchen-sink/i.rs
@@ -0,0 +1,30 @@
+//@ aux-build:r.rs
+//@ aux-build:q.rs
+//@ aux-build:t.rs
+//@ aux-build:s.rs
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+//@ has index.html '//h1' 'List of all crates'
+//@ has index.html
+//@ has index.html '//ul[@class="all-items"]//a[@href="i/index.html"]' 'i'
+//@ has index.html '//ul[@class="all-items"]//a[@href="q/index.html"]' 'q'
+//@ has index.html '//ul[@class="all-items"]//a[@href="r/index.html"]' 'r'
+//@ has index.html '//ul[@class="all-items"]//a[@href="s/index.html"]' 's'
+//@ has index.html '//ul[@class="all-items"]//a[@href="t/index.html"]' 't'
+//@ has q/struct.Quebec.html
+//@ has r/type.Romeo.html
+//@ has s/struct.Sierra.html
+//@ has t/trait.Tango.html
+//@ hasraw s/struct.Sierra.html 'Tango'
+//@ hasraw trait.impl/t/trait.Tango.js 'struct.Sierra.html'
+//@ hasraw search-index.js 'Quebec'
+//@ hasraw search-index.js 'Romeo'
+//@ hasraw search-index.js 'Sierra'
+//@ hasraw search-index.js 'Tango'
+//@ has type.impl/s/struct.Sierra.js
+//@ hasraw type.impl/s/struct.Sierra.js 'Tango'
+//@ hasraw type.impl/s/struct.Sierra.js 'Romeo'
+
+// document everything in the default mode
diff --git a/tests/rustdoc/cross-crate-info/single-crate-baseline/q.rs b/tests/rustdoc/cross-crate-info/single-crate-baseline/q.rs
new file mode 100644
index 00000000000..c5e3dc0a0f4
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/single-crate-baseline/q.rs
@@ -0,0 +1,12 @@
+//@ build-aux-docs
+//@ doc-flags:--enable-index-page
+//@ doc-flags:-Zunstable-options
+
+//@ has index.html
+//@ has index.html '//h1' 'List of all crates'
+//@ has index.html '//ul[@class="all-items"]//a[@href="q/index.html"]' 'q'
+//@ has q/struct.Quebec.html
+//@ hasraw search-index.js 'Quebec'
+
+// there's nothing cross-crate going on here
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/single-crate-no-index/q.rs b/tests/rustdoc/cross-crate-info/single-crate-no-index/q.rs
new file mode 100644
index 00000000000..d3e71fa0ce3
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/single-crate-no-index/q.rs
@@ -0,0 +1,6 @@
+//@ build-aux-docs
+//@ has q/struct.Quebec.html
+//@ hasraw search-index.js 'Quebec'
+
+// there's nothing cross-crate going on here
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/transitive/auxiliary/q.rs b/tests/rustdoc/cross-crate-info/transitive/auxiliary/q.rs
new file mode 100644
index 00000000000..5d0881029cb
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/transitive/auxiliary/q.rs
@@ -0,0 +1,2 @@
+//@ build-aux-docs
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/transitive/auxiliary/t.rs b/tests/rustdoc/cross-crate-info/transitive/auxiliary/t.rs
new file mode 100644
index 00000000000..fab9ec4a92b
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/transitive/auxiliary/t.rs
@@ -0,0 +1,4 @@
+//@ aux-build:q.rs
+//@ build-aux-docs
+extern crate q;
+pub trait Tango {}
diff --git a/tests/rustdoc/cross-crate-info/transitive/s.rs b/tests/rustdoc/cross-crate-info/transitive/s.rs
new file mode 100644
index 00000000000..0a4e5f646dd
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/transitive/s.rs
@@ -0,0 +1,6 @@
+//@ aux-build:t.rs
+//@ build-aux-docs
+// simple test to see if we support building transitive crates
+extern crate t;
+pub struct Sierra;
+impl t::Tango for Sierra {}
diff --git a/tests/rustdoc/cross-crate-info/two/auxiliary/f.rs b/tests/rustdoc/cross-crate-info/two/auxiliary/f.rs
new file mode 100644
index 00000000000..abc580a388c
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/two/auxiliary/f.rs
@@ -0,0 +1,2 @@
+//@ build-aux-docs
+pub trait Foxtrot {}
diff --git a/tests/rustdoc/cross-crate-info/two/e.rs b/tests/rustdoc/cross-crate-info/two/e.rs
new file mode 100644
index 00000000000..9665af62706
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/two/e.rs
@@ -0,0 +1,6 @@
+//@ aux-build:f.rs
+//@ build-aux-docs
+// simple test to assert that we can do a two-level aux-build
+extern crate f;
+pub enum Echo {}
+impl f::Foxtrot for Echo {}
diff --git a/tests/rustdoc/cross-crate-info/working-dir-examples/q.rs b/tests/rustdoc/cross-crate-info/working-dir-examples/q.rs
new file mode 100644
index 00000000000..a7ab062fd9e
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/working-dir-examples/q.rs
@@ -0,0 +1,10 @@
+//@ build-aux-docs
+//@ doc-flags:--scrape-examples-output-path=examples
+//@ doc-flags:--scrape-examples-target-crate=q
+//@ doc-flags:-Zunstable-options
+
+//@ has examples
+
+// where will --scrape-examples-output-path resolve the path to be?
+// should be the root output directory
+pub struct Quebec;
diff --git a/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/auxiliary/f.rs b/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/auxiliary/f.rs
new file mode 100644
index 00000000000..f8c9adcaf9c
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/auxiliary/f.rs
@@ -0,0 +1,3 @@
+//@ build-aux-docs
+//@ unique-doc-out-dir
+pub trait Foxtrot {}
diff --git a/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/e.rs b/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/e.rs
new file mode 100644
index 00000000000..9dcec211e17
--- /dev/null
+++ b/tests/rustdoc/cross-crate-info/write-docs-somewhere-else/e.rs
@@ -0,0 +1,14 @@
+//@ aux-build:f.rs
+//@ build-aux-docs
+//@ has e/enum.Echo.html
+//@ !has f/trait.Foxtrot.html
+//@ hasraw e/enum.Echo.html 'Foxtrot'
+//@ hasraw trait.impl/f/trait.Foxtrot.js 'enum.Echo.html'
+//@ !hasraw search-index.js 'Foxtrot'
+//@ hasraw search-index.js 'Echo'
+
+// test the fact that our test runner will document this crate somewhere
+// else
+extern crate f;
+pub enum Echo {}
+impl f::Foxtrot for Echo {}
diff --git a/tests/rustdoc/unsafe-extern-blocks.rs b/tests/rustdoc/unsafe-extern-blocks.rs
index 22d3beea6c3..829095f300f 100644
--- a/tests/rustdoc/unsafe-extern-blocks.rs
+++ b/tests/rustdoc/unsafe-extern-blocks.rs
@@ -1,6 +1,5 @@
 // Test to ensure the feature is working as expected.
 
-#![feature(unsafe_extern_blocks)]
 #![crate_name = "foo"]
 
 // @has 'foo/index.html'
@@ -13,7 +12,7 @@
 // @count - '//ul[@class="item-table"]//sup[@title="unsafe function"]' 1
 // @has - '//ul[@class="item-table"]//sup[@title="unsafe function"]' '⚠'
 
-unsafe extern {
+unsafe extern "C" {
     // @has 'foo/static.FOO.html'
     // @has - '//pre[@class="rust item-decl"]' 'pub static FOO: i32'
     pub safe static FOO: i32;
diff --git a/tests/ui/attributes/check-builtin-attr-ice.rs b/tests/ui/attributes/check-builtin-attr-ice.rs
new file mode 100644
index 00000000000..9ef5890601f
--- /dev/null
+++ b/tests/ui/attributes/check-builtin-attr-ice.rs
@@ -0,0 +1,58 @@
+//! Regression test for #128622.
+//!
+//! PR #128581 introduced an assertion that all builtin attributes are actually checked via
+//! `CheckAttrVisitor` and aren't accidentally usable on completely unrelated HIR nodes.
+//! Unfortunately, the check had correctness problems.
+//!
+//! The match on attribute path segments looked like
+//!
+//! ```rs,ignore
+//! [sym::should_panic] => /* check is implemented */
+//! match BUILTIN_ATTRIBUTE_MAP.get(name) {
+//!     // checked below
+//!     Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
+//!     Some(_) => {
+//!         if !name.as_str().starts_with("rustc_") {
+//!             span_bug!(
+//!                 attr.span,
+//!                 "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
+//!             )
+//!         }
+//!     }
+//!     None => (),
+//! }
+//! ```
+//!
+//! However, it failed to account for edge cases such as an attribute whose:
+//!
+//! 1. path segments *starts* with a builtin attribute such as `should_panic`
+//! 2. which does not start with `rustc_`, and
+//! 3. is also an `AttributeType::Normal` attribute upon registration with the builtin attribute map
+//!
+//! These conditions when all satisfied cause the span bug to be issued for e.g.
+//! `#[should_panic::skip]` because the `[sym::should_panic]` arm is not matched (since it's
+//! `[sym::should_panic, sym::skip]`).
+//!
+//! This test checks that the span bug is not fired for such cases.
+//!
+//! issue: rust-lang/rust#128622
+
+// Notably, `should_panic` is a `AttributeType::Normal` attribute that is checked separately.
+
+struct Foo {
+    #[should_panic::skip]
+    //~^ ERROR failed to resolve
+    pub field: u8,
+
+    #[should_panic::a::b::c]
+    //~^ ERROR failed to resolve
+    pub field2: u8,
+}
+
+fn foo() {}
+
+fn main() {
+    #[deny::skip]
+    //~^ ERROR failed to resolve
+    foo();
+}
diff --git a/tests/ui/attributes/check-builtin-attr-ice.stderr b/tests/ui/attributes/check-builtin-attr-ice.stderr
new file mode 100644
index 00000000000..5a27da565a8
--- /dev/null
+++ b/tests/ui/attributes/check-builtin-attr-ice.stderr
@@ -0,0 +1,21 @@
+error[E0433]: failed to resolve: use of undeclared crate or module `should_panic`
+  --> $DIR/check-builtin-attr-ice.rs:43:7
+   |
+LL |     #[should_panic::skip]
+   |       ^^^^^^^^^^^^ use of undeclared crate or module `should_panic`
+
+error[E0433]: failed to resolve: use of undeclared crate or module `should_panic`
+  --> $DIR/check-builtin-attr-ice.rs:47:7
+   |
+LL |     #[should_panic::a::b::c]
+   |       ^^^^^^^^^^^^ use of undeclared crate or module `should_panic`
+
+error[E0433]: failed to resolve: use of undeclared crate or module `deny`
+  --> $DIR/check-builtin-attr-ice.rs:55:7
+   |
+LL |     #[deny::skip]
+   |       ^^^^ use of undeclared crate or module `deny`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0433`.
diff --git a/tests/ui/check-cfg/mix.stderr b/tests/ui/check-cfg/mix.stderr
index 57cbe173c78..520cffc4b02 100644
--- a/tests/ui/check-cfg/mix.stderr
+++ b/tests/ui/check-cfg/mix.stderr
@@ -251,7 +251,7 @@ warning: unexpected `cfg` condition value: `zebra`
 LL |     cfg!(target_feature = "zebra");
    |          ^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, and `avx512vpopcntdq` and 199 more
+   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, and `avx512vpopcntdq` and 201 more
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: 27 warnings emitted
diff --git a/tests/ui/check-cfg/well-known-values.stderr b/tests/ui/check-cfg/well-known-values.stderr
index 00abb5f5e5c..d780e04e729 100644
--- a/tests/ui/check-cfg/well-known-values.stderr
+++ b/tests/ui/check-cfg/well-known-values.stderr
@@ -165,7 +165,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_feature = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, `avx512vpopcntdq`, `avxifma`, `avxneconvert`, `avxvnni`, `avxvnniint16`, `avxvnniint8`, `backchain`, `bf16`, `bmi1`, `bmi2`, `bti`, `bulk-memory`, `c`, `cache`, `cmpxchg16b`, `crc`, `crt-static`, `d`, `d32`, `dit`, `doloop`, `dotprod`, `dpb`, `dpb2`, `dsp`, `dsp1e2`, `dspe60`, `e`, `e1`, `e2`, `edsp`, `elrw`, `ermsb`, `exception-handling`, `extended-const`, `f`, `f16c`, `f32mm`, `f64mm`, `fcma`, `fdivdu`, `fhm`, `flagm`, `float1e2`, `float1e3`, `float3e4`, `float7e60`, `floate1`, `fma`, `fp-armv8`, `fp16`, `fp64`, `fpuv2_df`, `fpuv2_sf`, `fpuv3_df`, `fpuv3_hf`, `fpuv3_hi`, `fpuv3_sf`, `frecipe`, `frintts`, `fxsr`, `gfni`, `hard-float`, `hard-float-abi`, `hard-tp`, `high-registers`, `hvx`, `hvx-length128b`, `hwdiv`, `i8mm`, `jsconv`, `lahfsahf`, `lasx`, `lbt`, `lor`, `lse`, `lsx`, `lvz`, `lzcnt`, `m`, `mclass`, `movbe`, `mp`, `mp1e2`, `msa`, `mte`, `multivalue`, `mutable-globals`, `neon`, `nontrapping-fptoint`, `nvic`, `paca`, `pacg`, `pan`, `pclmulqdq`, `pmuv3`, `popcnt`, `power10-vector`, `power8-altivec`, `power8-vector`, `power9-altivec`, `power9-vector`, `prfchw`, `rand`, `ras`, `rclass`, `rcpc`, `rcpc2`, `rdm`, `rdrand`, `rdseed`, `reference-types`, `relax`, `relaxed-simd`, `rtm`, `sb`, `sha`, `sha2`, `sha3`, `sign-ext`, `simd128`, `sm4`, `spe`, `ssbs`, `sse`, `sse2`, `sse3`, `sse4.1`, `sse4.2`, `sse4a`, `ssse3`, `sve`, `sve2`, `sve2-aes`, `sve2-bitperm`, `sve2-sha3`, `sve2-sm4`, `tbm`, `thumb-mode`, `thumb2`, `tme`, `trust`, `trustzone`, `ual`, `unaligned-scalar-mem`, `v`, `v5te`, `v6`, `v6k`, `v6t2`, `v7`, `v8`, `v8.1a`, `v8.2a`, `v8.3a`, `v8.4a`, `v8.5a`, `v8.6a`, `v8.7a`, `vaes`, `vdsp2e60f`, `vdspv1`, `vdspv2`, `vector`, `vfp2`, `vfp3`, `vfp4`, `vh`, `virt`, `virtualization`, `vpclmulqdq`, `vsx`, `xop`, `xsave`, `xsavec`, `xsaveopt`, `xsaves`, `zba`, `zbb`, `zbc`, `zbkb`, `zbkc`, `zbkx`, `zbs`, `zdinx`, `zfh`, `zfhmin`, `zfinx`, `zhinx`, `zhinxmin`, `zk`, `zkn`, `zknd`, `zkne`, `zknh`, `zkr`, `zks`, `zksed`, `zksh`, and `zkt`
+   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, `avx512vpopcntdq`, `avxifma`, `avxneconvert`, `avxvnni`, `avxvnniint16`, `avxvnniint8`, `backchain`, `bf16`, `bmi1`, `bmi2`, `bti`, `bulk-memory`, `c`, `cache`, `cmpxchg16b`, `crc`, `crt-static`, `d`, `d32`, `dit`, `doloop`, `dotprod`, `dpb`, `dpb2`, `dsp`, `dsp1e2`, `dspe60`, `e`, `e1`, `e2`, `edsp`, `elrw`, `ermsb`, `exception-handling`, `extended-const`, `f`, `f16c`, `f32mm`, `f64mm`, `fcma`, `fdivdu`, `fhm`, `flagm`, `float1e2`, `float1e3`, `float3e4`, `float7e60`, `floate1`, `fma`, `fp-armv8`, `fp16`, `fp64`, `fpuv2_df`, `fpuv2_sf`, `fpuv3_df`, `fpuv3_hf`, `fpuv3_hi`, `fpuv3_sf`, `frecipe`, `frintts`, `fxsr`, `gfni`, `hard-float`, `hard-float-abi`, `hard-tp`, `high-registers`, `hvx`, `hvx-length128b`, `hwdiv`, `i8mm`, `jsconv`, `lahfsahf`, `lasx`, `lbt`, `lor`, `lse`, `lsx`, `lvz`, `lzcnt`, `m`, `mclass`, `movbe`, `mp`, `mp1e2`, `msa`, `mte`, `multivalue`, `mutable-globals`, `neon`, `nontrapping-fptoint`, `nvic`, `paca`, `pacg`, `pan`, `pclmulqdq`, `pmuv3`, `popcnt`, `power10-vector`, `power8-altivec`, `power8-vector`, `power9-altivec`, `power9-vector`, `prfchw`, `rand`, `ras`, `rclass`, `rcpc`, `rcpc2`, `rdm`, `rdrand`, `rdseed`, `reference-types`, `relax`, `relaxed-simd`, `rtm`, `sb`, `sha`, `sha2`, `sha3`, `sha512`, `sign-ext`, `simd128`, `sm3`, `sm4`, `spe`, `ssbs`, `sse`, `sse2`, `sse3`, `sse4.1`, `sse4.2`, `sse4a`, `ssse3`, `sve`, `sve2`, `sve2-aes`, `sve2-bitperm`, `sve2-sha3`, `sve2-sm4`, `tbm`, `thumb-mode`, `thumb2`, `tme`, `trust`, `trustzone`, `ual`, `unaligned-scalar-mem`, `v`, `v5te`, `v6`, `v6k`, `v6t2`, `v7`, `v8`, `v8.1a`, `v8.2a`, `v8.3a`, `v8.4a`, `v8.5a`, `v8.6a`, `v8.7a`, `vaes`, `vdsp2e60f`, `vdspv1`, `vdspv2`, `vector`, `vfp2`, `vfp3`, `vfp4`, `vh`, `virt`, `virtualization`, `vpclmulqdq`, `vsx`, `xop`, `xsave`, `xsavec`, `xsaveopt`, `xsaves`, `zba`, `zbb`, `zbc`, `zbkb`, `zbkc`, `zbkx`, `zbs`, `zdinx`, `zfh`, `zfhmin`, `zfinx`, `zhinx`, `zhinxmin`, `zk`, `zkn`, `zknd`, `zkne`, `zknh`, `zkr`, `zks`, `zksed`, `zksh`, and `zkt`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
diff --git a/tests/ui/coherence/re-rebalance-coherence.rs b/tests/ui/coherence/re-rebalance-coherence.rs
index 5383a634617..9c176d5b1b1 100644
--- a/tests/ui/coherence/re-rebalance-coherence.rs
+++ b/tests/ui/coherence/re-rebalance-coherence.rs
@@ -4,7 +4,6 @@
 extern crate re_rebalance_coherence_lib as lib;
 use lib::*;
 
-#[allow(dead_code)]
 struct Oracle;
 impl Backend for Oracle {}
 impl<'a, T:'a, Tab> QueryFragment<Oracle> for BatchInsert<'a, T, Tab> {}
diff --git a/tests/ui/const-generics/cross_crate_complex.rs b/tests/ui/const-generics/cross_crate_complex.rs
index b44d889f5e9..d13b69aa0cf 100644
--- a/tests/ui/const-generics/cross_crate_complex.rs
+++ b/tests/ui/const-generics/cross_crate_complex.rs
@@ -11,7 +11,6 @@ async fn foo() {
     async_in_foo(async_out_foo::<4>().await).await;
 }
 
-#[allow(dead_code)]
 struct Faz<const N: usize>;
 
 impl<const N: usize> Foo<N> for Faz<N> {}
diff --git a/tests/ui/const-generics/defaults/repr-c-issue-82792.rs b/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
index 4bf2fa761ea..c23187598bc 100644
--- a/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
+++ b/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
@@ -2,7 +2,6 @@
 
 //@ run-pass
 
-#[allow(dead_code)]
 #[repr(C)]
 pub struct Loaf<T: Sized, const N: usize = 1> {
     head: [T; N],
diff --git a/tests/ui/const-generics/generic_const_exprs/associated-consts.rs b/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
index 50a6102c605..5d2198f50ad 100644
--- a/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
+++ b/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
@@ -16,8 +16,7 @@ impl BlockCipher for BarCipher {
     const BLOCK_SIZE: usize = 32;
 }
 
-#[allow(dead_code)]
-pub struct Block<C>(C);
+pub struct Block<C>(#[allow(dead_code)] C);
 
 pub fn test<C: BlockCipher, const M: usize>()
 where
diff --git a/tests/ui/const-generics/generic_const_exprs/issue-105608.stderr b/tests/ui/const-generics/generic_const_exprs/issue-105608.stderr
index 09b618fb3f0..1c97eaddfe1 100644
--- a/tests/ui/const-generics/generic_const_exprs/issue-105608.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/issue-105608.stderr
@@ -4,10 +4,6 @@ error[E0282]: type annotations needed
 LL |     Combination::<0>.and::<_>().and::<_>();
    |                      ^^^ cannot infer type of the type parameter `M` declared on the method `and`
    |
-help: consider specifying the generic argument
-   |
-LL |     Combination::<0>.and::<_>().and::<_>();
-   |                         ~~~~~
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/const-generics/issues/issue-86535-2.rs b/tests/ui/const-generics/issues/issue-86535-2.rs
index ab68c6b78df..8d064f3eeb1 100644
--- a/tests/ui/const-generics/issues/issue-86535-2.rs
+++ b/tests/ui/const-generics/issues/issue-86535-2.rs
@@ -9,7 +9,6 @@ pub trait Foo {
         [(); Self::ASSOC_C]:;
 }
 
-#[allow(dead_code)]
 struct Bar<const N: &'static ()>;
 impl<const N: &'static ()> Foo for Bar<N> {
     const ASSOC_C: usize = 3;
diff --git a/tests/ui/const-generics/issues/issue-86535.rs b/tests/ui/const-generics/issues/issue-86535.rs
index 9aaf7ddc9e8..62454f4a388 100644
--- a/tests/ui/const-generics/issues/issue-86535.rs
+++ b/tests/ui/const-generics/issues/issue-86535.rs
@@ -2,7 +2,6 @@
 #![feature(adt_const_params, unsized_const_params, generic_const_exprs)]
 #![allow(incomplete_features, unused_variables)]
 
-#[allow(dead_code)]
 struct F<const S: &'static str>;
 impl<const S: &'static str> X for F<{ S }> {
     const W: usize = 3;
diff --git a/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs b/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
index 35c41ae4615..419d605d0c8 100644
--- a/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
+++ b/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
@@ -6,7 +6,6 @@
 
 use std::mem::MaybeUninit;
 
-#[allow(dead_code)]
 #[repr(transparent)]
 pub struct MaybeUninitWrapper<const N: usize>(MaybeUninit<[u64; N]>);
 
diff --git a/tests/ui/coroutine/invalid_attr_usage.rs b/tests/ui/coroutine/invalid_attr_usage.rs
new file mode 100644
index 00000000000..995a3aa3100
--- /dev/null
+++ b/tests/ui/coroutine/invalid_attr_usage.rs
@@ -0,0 +1,11 @@
+//! The `coroutine` attribute is only allowed on closures.
+
+#![feature(coroutines)]
+
+#[coroutine]
+//~^ ERROR: attribute should be applied to closures
+struct Foo;
+
+#[coroutine]
+//~^ ERROR: attribute should be applied to closures
+fn main() {}
diff --git a/tests/ui/coroutine/invalid_attr_usage.stderr b/tests/ui/coroutine/invalid_attr_usage.stderr
new file mode 100644
index 00000000000..316a0117e5d
--- /dev/null
+++ b/tests/ui/coroutine/invalid_attr_usage.stderr
@@ -0,0 +1,14 @@
+error: attribute should be applied to closures
+  --> $DIR/invalid_attr_usage.rs:5:1
+   |
+LL | #[coroutine]
+   | ^^^^^^^^^^^^
+
+error: attribute should be applied to closures
+  --> $DIR/invalid_attr_usage.rs:9:1
+   |
+LL | #[coroutine]
+   | ^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/feature-gates/feature-gate-sha512_sm_x86.rs b/tests/ui/feature-gates/feature-gate-sha512_sm_x86.rs
new file mode 100644
index 00000000000..176a40ecf53
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-sha512_sm_x86.rs
@@ -0,0 +1,6 @@
+//@ only-x86_64
+#[target_feature(enable = "sha512")]
+//~^ ERROR: currently unstable
+unsafe fn foo() {}
+
+fn main() {}
diff --git a/tests/ui/feature-gates/feature-gate-sha512_sm_x86.stderr b/tests/ui/feature-gates/feature-gate-sha512_sm_x86.stderr
new file mode 100644
index 00000000000..da9eea095a3
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-sha512_sm_x86.stderr
@@ -0,0 +1,13 @@
+error[E0658]: the target feature `sha512` is currently unstable
+  --> $DIR/feature-gate-sha512_sm_x86.rs:2:18
+   |
+LL | #[target_feature(enable = "sha512")]
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #126624 <https://github.com/rust-lang/rust/issues/126624> for more information
+   = help: add `#![feature(sha512_sm_x86)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.rs b/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.rs
deleted file mode 100644
index 3ea62e875b8..00000000000
--- a/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-unsafe extern "C" {
-    //~^ ERROR extern block cannot be declared unsafe
-}
-
-// We can't gate `unsafe extern` blocks themselves since they were previously
-// allowed, but we should gate the `safe` soft keyword.
-#[cfg(any())]
-unsafe extern "C" {
-    safe fn foo();
-    //~^ ERROR `unsafe extern {}` blocks and `safe` keyword are experimental
-}
-
-fn main() {}
diff --git a/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.stderr b/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.stderr
deleted file mode 100644
index 56534946308..00000000000
--- a/tests/ui/feature-gates/feature-gate-unsafe-extern-blocks.stderr
+++ /dev/null
@@ -1,23 +0,0 @@
-error: extern block cannot be declared unsafe
-  --> $DIR/feature-gate-unsafe-extern-blocks.rs:1:1
-   |
-LL | unsafe extern "C" {
-   | ^^^^^^
-   |
-   = note: see issue #123743 <https://github.com/rust-lang/rust/issues/123743> for more information
-   = help: add `#![feature(unsafe_extern_blocks)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error[E0658]: `unsafe extern {}` blocks and `safe` keyword are experimental
-  --> $DIR/feature-gate-unsafe-extern-blocks.rs:9:5
-   |
-LL |     safe fn foo();
-   |     ^^^^
-   |
-   = note: see issue #123743 <https://github.com/rust-lang/rust/issues/123743> for more information
-   = help: add `#![feature(unsafe_extern_blocks)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/generic-associated-types/missing-bounds.fixed b/tests/ui/generic-associated-types/missing-bounds.fixed
index ff69016d862..703d3c1e0fb 100644
--- a/tests/ui/generic-associated-types/missing-bounds.fixed
+++ b/tests/ui/generic-associated-types/missing-bounds.fixed
@@ -2,7 +2,6 @@
 
 use std::ops::Add;
 
-#[allow(dead_code)]
 struct A<B>(B);
 
 impl<B> Add for A<B> where B: Add<Output = B> {
@@ -13,7 +12,6 @@ impl<B> Add for A<B> where B: Add<Output = B> {
     }
 }
 
-#[allow(dead_code)]
 struct C<B>(B);
 
 impl<B: Add<Output = B>> Add for C<B> {
@@ -24,7 +22,6 @@ impl<B: Add<Output = B>> Add for C<B> {
     }
 }
 
-#[allow(dead_code)]
 struct D<B>(B);
 
 impl<B: std::ops::Add<Output = B>> Add for D<B> {
@@ -35,7 +32,6 @@ impl<B: std::ops::Add<Output = B>> Add for D<B> {
     }
 }
 
-#[allow(dead_code)]
 struct E<B>(B);
 
 impl<B: Add<Output = B>> Add for E<B> where B: Add<Output = B> {
diff --git a/tests/ui/generic-associated-types/missing-bounds.rs b/tests/ui/generic-associated-types/missing-bounds.rs
index 1f83356c2fa..f40b4228873 100644
--- a/tests/ui/generic-associated-types/missing-bounds.rs
+++ b/tests/ui/generic-associated-types/missing-bounds.rs
@@ -2,7 +2,6 @@
 
 use std::ops::Add;
 
-#[allow(dead_code)]
 struct A<B>(B);
 
 impl<B> Add for A<B> where B: Add {
@@ -13,7 +12,6 @@ impl<B> Add for A<B> where B: Add {
     }
 }
 
-#[allow(dead_code)]
 struct C<B>(B);
 
 impl<B: Add> Add for C<B> {
@@ -24,7 +22,6 @@ impl<B: Add> Add for C<B> {
     }
 }
 
-#[allow(dead_code)]
 struct D<B>(B);
 
 impl<B> Add for D<B> {
@@ -35,7 +32,6 @@ impl<B> Add for D<B> {
     }
 }
 
-#[allow(dead_code)]
 struct E<B>(B);
 
 impl<B: Add> Add for E<B> where <B as Add>::Output = B {
diff --git a/tests/ui/generic-associated-types/missing-bounds.stderr b/tests/ui/generic-associated-types/missing-bounds.stderr
index 0f0dc24c06c..1d7d80d1b07 100644
--- a/tests/ui/generic-associated-types/missing-bounds.stderr
+++ b/tests/ui/generic-associated-types/missing-bounds.stderr
@@ -1,5 +1,5 @@
 error: equality constraints are not yet supported in `where` clauses
-  --> $DIR/missing-bounds.rs:41:33
+  --> $DIR/missing-bounds.rs:37:33
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |                                 ^^^^^^^^^^^^^^^^^^^^^^ not supported
@@ -11,7 +11,7 @@ LL | impl<B: Add> Add for E<B> where B: Add<Output = B> {
    |                                 ~~~~~~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:12:11
+  --> $DIR/missing-bounds.rs:11:11
    |
 LL | impl<B> Add for A<B> where B: Add {
    |      - expected this type parameter
@@ -24,14 +24,14 @@ LL |         A(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 help: the type constructed contains `<B as Add>::Output` due to the type of the argument passed
-  --> $DIR/missing-bounds.rs:12:9
+  --> $DIR/missing-bounds.rs:11:9
    |
 LL |         A(self.0 + rhs.0)
    |         ^^--------------^
    |           |
    |           this argument influences the type of `A`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:6:8
+  --> $DIR/missing-bounds.rs:5:8
    |
 LL | struct A<B>(B);
    |        ^
@@ -41,7 +41,7 @@ LL | impl<B> Add for A<B> where B: Add<Output = B> {
    |                                  ++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:23:14
+  --> $DIR/missing-bounds.rs:21:14
    |
 LL | impl<B: Add> Add for C<B> {
    |      - expected this type parameter
@@ -54,7 +54,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:17:8
+  --> $DIR/missing-bounds.rs:15:8
    |
 LL | struct C<B>(B);
    |        ^
@@ -64,7 +64,7 @@ LL | impl<B: Add<Output = B>> Add for C<B> {
    |            ++++++++++++
 
 error[E0369]: cannot add `B` to `B`
-  --> $DIR/missing-bounds.rs:34:21
+  --> $DIR/missing-bounds.rs:31:21
    |
 LL |         Self(self.0 + rhs.0)
    |              ------ ^ ----- B
@@ -77,7 +77,7 @@ LL | impl<B: std::ops::Add<Output = B>> Add for D<B> {
    |       +++++++++++++++++++++++++++
 
 error[E0308]: mismatched types
-  --> $DIR/missing-bounds.rs:46:14
+  --> $DIR/missing-bounds.rs:42:14
    |
 LL | impl<B: Add> Add for E<B> where <B as Add>::Output = B {
    |      - expected this type parameter
@@ -90,7 +90,7 @@ LL |         Self(self.0 + rhs.0)
    = note: expected type parameter `B`
              found associated type `<B as Add>::Output`
 note: tuple struct defined here
-  --> $DIR/missing-bounds.rs:39:8
+  --> $DIR/missing-bounds.rs:35:8
    |
 LL | struct E<B>(B);
    |        ^
diff --git a/tests/ui/impl-trait/extra-impl-in-trait-impl.fixed b/tests/ui/impl-trait/extra-impl-in-trait-impl.fixed
index 3c4499f0173..886fc1d0058 100644
--- a/tests/ui/impl-trait/extra-impl-in-trait-impl.fixed
+++ b/tests/ui/impl-trait/extra-impl-in-trait-impl.fixed
@@ -1,8 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct S<T>(T);
-#[allow(dead_code)]
 struct S2;
 
 impl<T: Default> Default for S<T> {
diff --git a/tests/ui/impl-trait/extra-impl-in-trait-impl.rs b/tests/ui/impl-trait/extra-impl-in-trait-impl.rs
index ac078329524..f3271993867 100644
--- a/tests/ui/impl-trait/extra-impl-in-trait-impl.rs
+++ b/tests/ui/impl-trait/extra-impl-in-trait-impl.rs
@@ -1,8 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct S<T>(T);
-#[allow(dead_code)]
 struct S2;
 
 impl<T: Default> impl Default for S<T> {
diff --git a/tests/ui/impl-trait/extra-impl-in-trait-impl.stderr b/tests/ui/impl-trait/extra-impl-in-trait-impl.stderr
index 91c7da5a04f..5aafc8b64d4 100644
--- a/tests/ui/impl-trait/extra-impl-in-trait-impl.stderr
+++ b/tests/ui/impl-trait/extra-impl-in-trait-impl.stderr
@@ -1,23 +1,23 @@
 error: unexpected `impl` keyword
-  --> $DIR/extra-impl-in-trait-impl.rs:8:18
+  --> $DIR/extra-impl-in-trait-impl.rs:6:18
    |
 LL | impl<T: Default> impl Default for S<T> {
    |                  ^^^^^ help: remove the extra `impl`
    |
 note: this is parsed as an `impl Trait` type, but a trait is expected at this position
-  --> $DIR/extra-impl-in-trait-impl.rs:8:18
+  --> $DIR/extra-impl-in-trait-impl.rs:6:18
    |
 LL | impl<T: Default> impl Default for S<T> {
    |                  ^^^^^^^^^^^^
 
 error: unexpected `impl` keyword
-  --> $DIR/extra-impl-in-trait-impl.rs:14:6
+  --> $DIR/extra-impl-in-trait-impl.rs:12:6
    |
 LL | impl impl Default for S2 {
    |      ^^^^^ help: remove the extra `impl`
    |
 note: this is parsed as an `impl Trait` type, but a trait is expected at this position
-  --> $DIR/extra-impl-in-trait-impl.rs:14:6
+  --> $DIR/extra-impl-in-trait-impl.rs:12:6
    |
 LL | impl impl Default for S2 {
    |      ^^^^^^^^^^^^
diff --git a/tests/ui/imports/issue-55884-2.stderr b/tests/ui/imports/issue-55884-2.stderr
index 8a9d5f2a6d8..0d4f01aeafc 100644
--- a/tests/ui/imports/issue-55884-2.stderr
+++ b/tests/ui/imports/issue-55884-2.stderr
@@ -24,10 +24,6 @@ note: ...and refers to the struct `ParseOptions` which is defined here
    |
 LL |     pub struct ParseOptions {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^ you could import this directly
-help: import `ParseOptions` through the re-export
-   |
-LL | pub use parser::ParseOptions;
-   |         ~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.rs b/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.rs
index 0e894ef581c..ab46fd796c5 100644
--- a/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.rs
+++ b/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.rs
@@ -10,7 +10,7 @@ const RAW_EQ_PADDING: bool = unsafe {
 const RAW_EQ_PTR: bool = unsafe {
     std::intrinsics::raw_eq(&(&0), &(&1))
 //~^ ERROR evaluation of constant value failed
-//~| `raw_eq` on bytes with provenance
+//~| unable to turn pointer into integer
 };
 
 pub fn main() {
diff --git a/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.stderr b/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.stderr
index 317466eb322..af16c2bc64a 100644
--- a/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.stderr
+++ b/tests/ui/intrinsics/intrinsic-raw_eq-const-bad.stderr
@@ -8,7 +8,10 @@ error[E0080]: evaluation of constant value failed
   --> $DIR/intrinsic-raw_eq-const-bad.rs:11:5
    |
 LL |     std::intrinsics::raw_eq(&(&0), &(&1))
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `raw_eq` on bytes with provenance
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into integer
+   |
+   = help: this code performed an operation that depends on the underlying bytes representing a pointer
+   = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/issues/issue-5708.rs b/tests/ui/issues/issue-5708.rs
index 89ea9fbdcd8..ce9ef78ffcd 100644
--- a/tests/ui/issues/issue-5708.rs
+++ b/tests/ui/issues/issue-5708.rs
@@ -44,7 +44,6 @@ pub trait MyTrait<T> {
     fn dummy(&self, t: T) -> T { panic!() }
 }
 
-#[allow(dead_code)]
 pub struct MyContainer<'a, T:'a> {
     foos: Vec<&'a (dyn MyTrait<T>+'a)> ,
 }
diff --git a/tests/ui/lint/dead-code/allow-unconstructed-pub-struct.rs b/tests/ui/lint/dead-code/allow-unconstructed-pub-struct.rs
deleted file mode 100644
index 8cd1524045b..00000000000
--- a/tests/ui/lint/dead-code/allow-unconstructed-pub-struct.rs
+++ /dev/null
@@ -1,33 +0,0 @@
-//@ check-pass
-
-mod ffi {
-    use super::*;
-
-    extern "C" {
-        pub fn DomPromise_AddRef(promise: *const Promise);
-        pub fn DomPromise_Release(promise: *const Promise);
-    }
-}
-
-#[repr(C)]
-#[allow(unused)]
-pub struct Promise {
-    private: [u8; 0],
-    __nosync: ::std::marker::PhantomData<::std::rc::Rc<u8>>,
-}
-
-pub unsafe trait RefCounted {
-    unsafe fn addref(&self);
-    unsafe fn release(&self);
-}
-
-unsafe impl RefCounted for Promise {
-    unsafe fn addref(&self) {
-        ffi::DomPromise_AddRef(self)
-    }
-    unsafe fn release(&self) {
-        ffi::DomPromise_Release(self)
-    }
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/issue-59003.rs b/tests/ui/lint/dead-code/issue-59003.rs
index 319cf2db149..e3dcaca5778 100644
--- a/tests/ui/lint/dead-code/issue-59003.rs
+++ b/tests/ui/lint/dead-code/issue-59003.rs
@@ -4,8 +4,8 @@
 
 #![deny(dead_code)]
 
-#[allow(dead_code)]
 struct Foo {
+    #[allow(dead_code)]
     inner: u32,
 }
 
diff --git a/tests/ui/lint/dead-code/lint-dead-code-1.rs b/tests/ui/lint/dead-code/lint-dead-code-1.rs
index 3386dfa4747..ddcafedf7bc 100644
--- a/tests/ui/lint/dead-code/lint-dead-code-1.rs
+++ b/tests/ui/lint/dead-code/lint-dead-code-1.rs
@@ -46,10 +46,11 @@ struct SemiUsedStruct;
 impl SemiUsedStruct {
     fn la_la_la() {}
 }
-struct StructUsedAsField; //~ ERROR struct `StructUsedAsField` is never constructed
+struct StructUsedAsField;
 pub struct StructUsedInEnum;
 struct StructUsedInGeneric;
-pub struct PubStruct2 { //~ ERROR struct `PubStruct2` is never constructed
+pub struct PubStruct2 {
+    #[allow(dead_code)]
     struct_used_as_field: *const StructUsedAsField
 }
 
diff --git a/tests/ui/lint/dead-code/lint-dead-code-1.stderr b/tests/ui/lint/dead-code/lint-dead-code-1.stderr
index b0163df8855..eb728b5b930 100644
--- a/tests/ui/lint/dead-code/lint-dead-code-1.stderr
+++ b/tests/ui/lint/dead-code/lint-dead-code-1.stderr
@@ -22,26 +22,14 @@ error: struct `PrivStruct` is never constructed
 LL | struct PrivStruct;
    |        ^^^^^^^^^^
 
-error: struct `StructUsedAsField` is never constructed
-  --> $DIR/lint-dead-code-1.rs:49:8
-   |
-LL | struct StructUsedAsField;
-   |        ^^^^^^^^^^^^^^^^^
-
-error: struct `PubStruct2` is never constructed
-  --> $DIR/lint-dead-code-1.rs:52:12
-   |
-LL | pub struct PubStruct2 {
-   |            ^^^^^^^^^^
-
 error: enum `priv_enum` is never used
-  --> $DIR/lint-dead-code-1.rs:63:6
+  --> $DIR/lint-dead-code-1.rs:64:6
    |
 LL | enum priv_enum { foo2, bar2 }
    |      ^^^^^^^^^
 
 error: variant `bar3` is never constructed
-  --> $DIR/lint-dead-code-1.rs:66:5
+  --> $DIR/lint-dead-code-1.rs:67:5
    |
 LL | enum used_enum {
    |      --------- variant in this enum
@@ -50,25 +38,25 @@ LL |     bar3
    |     ^^^^
 
 error: function `priv_fn` is never used
-  --> $DIR/lint-dead-code-1.rs:87:4
+  --> $DIR/lint-dead-code-1.rs:88:4
    |
 LL | fn priv_fn() {
    |    ^^^^^^^
 
 error: function `foo` is never used
-  --> $DIR/lint-dead-code-1.rs:92:4
+  --> $DIR/lint-dead-code-1.rs:93:4
    |
 LL | fn foo() {
    |    ^^^
 
 error: function `bar` is never used
-  --> $DIR/lint-dead-code-1.rs:97:4
+  --> $DIR/lint-dead-code-1.rs:98:4
    |
 LL | fn bar() {
    |    ^^^
 
 error: function `baz` is never used
-  --> $DIR/lint-dead-code-1.rs:101:4
+  --> $DIR/lint-dead-code-1.rs:102:4
    |
 LL | fn baz() -> impl Copy {
    |    ^^^
@@ -79,5 +67,5 @@ error: struct `Bar` is never constructed
 LL |     pub struct Bar;
    |                ^^^
 
-error: aborting due to 12 previous errors
+error: aborting due to 10 previous errors
 
diff --git a/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.rs b/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.rs
deleted file mode 100644
index 25777438456..00000000000
--- a/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-#![deny(dead_code)]
-
-struct Foo(u8); //~ ERROR struct `Foo` is never constructed
-
-enum Bar { //~ ERROR enum `Bar` is never used
-    Var1(u8),
-    Var2(u8),
-}
-
-pub trait Tr1 {
-    fn f1() -> Self;
-}
-
-impl Tr1 for Foo {
-    fn f1() -> Foo {
-        let f = Foo(0);
-        let Foo(tag) = f;
-        Foo(tag)
-    }
-}
-
-impl Tr1 for Bar {
-    fn f1() -> Bar {
-        let b = Bar::Var1(0);
-        let b = if let Bar::Var1(_) = b {
-            Bar::Var1(0)
-        } else {
-            Bar::Var2(0)
-        };
-        match b {
-            Bar::Var1(_) => Bar::Var2(0),
-            Bar::Var2(_) => Bar::Var1(0),
-        }
-    }
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.stderr b/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.stderr
deleted file mode 100644
index 7c1a4b45977..00000000000
--- a/tests/ui/lint/dead-code/lint-unused-adt-appeared-in-pattern.stderr
+++ /dev/null
@@ -1,20 +0,0 @@
-error: struct `Foo` is never constructed
-  --> $DIR/lint-unused-adt-appeared-in-pattern.rs:3:8
-   |
-LL | struct Foo(u8);
-   |        ^^^
-   |
-note: the lint level is defined here
-  --> $DIR/lint-unused-adt-appeared-in-pattern.rs:1:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: enum `Bar` is never used
-  --> $DIR/lint-unused-adt-appeared-in-pattern.rs:5:6
-   |
-LL | enum Bar {
-   |      ^^^
-
-error: aborting due to 2 previous errors
-
diff --git a/tests/ui/lint/dead-code/not-lint-used-adt-appeared-in-pattern.rs b/tests/ui/lint/dead-code/not-lint-used-adt-appeared-in-pattern.rs
deleted file mode 100644
index 43a2e431904..00000000000
--- a/tests/ui/lint/dead-code/not-lint-used-adt-appeared-in-pattern.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-//@ check-pass
-
-#![deny(dead_code)]
-
-#[repr(u8)]
-#[derive(Copy, Clone, Debug)]
-pub enum RecordField {
-    Target = 1,
-    Level,
-    Module,
-    File,
-    Line,
-    NumArgs,
-}
-
-unsafe trait Pod {}
-
-#[repr(transparent)]
-struct RecordFieldWrapper(RecordField);
-
-unsafe impl Pod for RecordFieldWrapper {}
-
-fn try_read<T: Pod>(buf: &[u8]) -> T {
-    unsafe { std::ptr::read_unaligned(buf.as_ptr() as *const T) }
-}
-
-pub fn foo(buf: &[u8]) -> RecordField {
-    let RecordFieldWrapper(tag) = try_read(buf);
-    tag
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unconstructible-pub-struct.rs b/tests/ui/lint/dead-code/unconstructible-pub-struct.rs
deleted file mode 100644
index 2202cbb6730..00000000000
--- a/tests/ui/lint/dead-code/unconstructible-pub-struct.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-#![feature(never_type)]
-#![deny(dead_code)]
-
-pub struct T1(!);
-pub struct T2(());
-pub struct T3<X>(std::marker::PhantomData<X>);
-
-pub struct T4 {
-    _x: !,
-}
-
-pub struct T5<X> {
-    _x: !,
-    _y: X,
-}
-
-pub struct T6 {
-    _x: (),
-}
-
-pub struct T7<X> {
-    _x: (),
-    _y: X,
-}
-
-pub struct T8<X> {
-    _x: std::marker::PhantomData<X>,
-}
-
-pub struct T9<X> { //~ ERROR struct `T9` is never constructed
-    _x: std::marker::PhantomData<X>,
-    _y: i32,
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr b/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr
deleted file mode 100644
index a3dde042bbe..00000000000
--- a/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: struct `T9` is never constructed
-  --> $DIR/unconstructible-pub-struct.rs:30:12
-   |
-LL | pub struct T9<X> {
-   |            ^^
-   |
-note: the lint level is defined here
-  --> $DIR/unconstructible-pub-struct.rs:2:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.rs b/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.rs
index 658cc3d6c61..5b755d62a05 100644
--- a/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.rs
+++ b/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.rs
@@ -1,9 +1,8 @@
 #![deny(dead_code)]
 
 struct T1; //~ ERROR struct `T1` is never constructed
-struct T2; //~ ERROR struct `T2` is never constructed
-pub struct T3(i32); //~ ERROR struct `T3` is never constructed
-pub struct T4(i32); //~ ERROR field `0` is never read
+pub struct T2(i32); //~ ERROR field `0` is never read
+struct T3;
 
 trait Trait1 { //~ ERROR trait `Trait1` is never used
     const UNUSED: i32;
@@ -12,13 +11,13 @@ trait Trait1 { //~ ERROR trait `Trait1` is never used
 }
 
 pub trait Trait2 {
-    const MAY_USED: i32;
-    fn may_used(&self) {}
+    const USED: i32;
+    fn used(&self) {}
 }
 
 pub trait Trait3 {
-    const MAY_USED: i32;
-    fn may_used() -> Self;
+    const USED: i32;
+    fn construct_self() -> Self;
 }
 
 impl Trait1 for T1 {
@@ -31,34 +30,23 @@ impl Trait1 for T1 {
 impl Trait1 for T2 {
     const UNUSED: i32 = 0;
     fn construct_self() -> Self {
-        Self
+        T2(0)
     }
 }
 
 impl Trait2 for T1 {
-    const MAY_USED: i32 = 0;
+    const USED: i32 = 0;
 }
 
 impl Trait2 for T2 {
-    const MAY_USED: i32 = 0;
+    const USED: i32 = 0;
 }
 
-impl Trait2 for T3 {
-    const MAY_USED: i32 = 0;
-}
-
-impl Trait3 for T2 {
-    const MAY_USED: i32 = 0;
-    fn may_used() -> Self {
+impl Trait3 for T3 {
+    const USED: i32 = 0;
+    fn construct_self() -> Self {
         Self
     }
 }
 
-impl Trait3 for T4 {
-    const MAY_USED: i32 = 0;
-    fn may_used() -> Self {
-        T4(0)
-    }
-}
-
 fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.stderr b/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.stderr
index 08c7a5cb4b0..2441a3f868d 100644
--- a/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.stderr
+++ b/tests/ui/lint/dead-code/unused-adt-impl-pub-trait-with-assoc-const.stderr
@@ -10,22 +10,10 @@ note: the lint level is defined here
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^
 
-error: struct `T2` is never constructed
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:8
-   |
-LL | struct T2;
-   |        ^^
-
-error: struct `T3` is never constructed
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:5:12
-   |
-LL | pub struct T3(i32);
-   |            ^^
-
 error: field `0` is never read
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:6:15
+  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:15
    |
-LL | pub struct T4(i32);
+LL | pub struct T2(i32);
    |            -- ^^^
    |            |
    |            field in this struct
@@ -33,10 +21,10 @@ LL | pub struct T4(i32);
    = help: consider removing this field
 
 error: trait `Trait1` is never used
-  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:8:7
+  --> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:7:7
    |
 LL | trait Trait1 {
    |       ^^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
diff --git a/tests/ui/lint/dead-code/unused-assoc-const.rs b/tests/ui/lint/dead-code/unused-assoc-const.rs
deleted file mode 100644
index 36e8315ad36..00000000000
--- a/tests/ui/lint/dead-code/unused-assoc-const.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-#![deny(dead_code)]
-
-trait Trait {
-    const UNUSED_CONST: i32; //~ ERROR associated constant `UNUSED_CONST` is never used
-    const USED_CONST: i32;
-
-    fn foo(&self) {}
-}
-
-pub struct T(());
-
-impl Trait for T {
-    const UNUSED_CONST: i32 = 0;
-    const USED_CONST: i32 = 1;
-}
-
-fn main() {
-    T(()).foo();
-    T::USED_CONST;
-}
diff --git a/tests/ui/lint/dead-code/unused-assoc-const.stderr b/tests/ui/lint/dead-code/unused-assoc-const.stderr
deleted file mode 100644
index 78296d70663..00000000000
--- a/tests/ui/lint/dead-code/unused-assoc-const.stderr
+++ /dev/null
@@ -1,16 +0,0 @@
-error: associated constant `UNUSED_CONST` is never used
-  --> $DIR/unused-assoc-const.rs:4:11
-   |
-LL | trait Trait {
-   |       ----- associated constant in this trait
-LL |     const UNUSED_CONST: i32;
-   |           ^^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/unused-assoc-const.rs:1:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs b/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs
deleted file mode 100644
index 46065dcee81..00000000000
--- a/tests/ui/lint/dead-code/unused-impl-for-non-adts.rs
+++ /dev/null
@@ -1,45 +0,0 @@
-#![deny(dead_code)]
-
-struct Foo; //~ ERROR struct `Foo` is never constructed
-
-trait Trait { //~ ERROR trait `Trait` is never used
-    fn foo(&self) {}
-}
-
-impl Trait for Foo {}
-
-impl Trait for [Foo] {}
-impl<const N: usize> Trait for [Foo; N] {}
-
-impl Trait for *const Foo {}
-impl Trait for *mut Foo {}
-
-impl Trait for &Foo {}
-impl Trait for &&Foo {}
-impl Trait for &mut Foo {}
-
-impl Trait for [&Foo] {}
-impl Trait for &[Foo] {}
-impl Trait for &*const Foo {}
-
-pub trait Trait2 {
-    fn foo(&self) {}
-}
-
-impl Trait2 for Foo {}
-
-impl Trait2 for [Foo] {}
-impl<const N: usize> Trait2 for [Foo; N] {}
-
-impl Trait2 for *const Foo {}
-impl Trait2 for *mut Foo {}
-
-impl Trait2 for &Foo {}
-impl Trait2 for &&Foo {}
-impl Trait2 for &mut Foo {}
-
-impl Trait2 for [&Foo] {}
-impl Trait2 for &[Foo] {}
-impl Trait2 for &*const Foo {}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr b/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr
deleted file mode 100644
index e61fc403e81..00000000000
--- a/tests/ui/lint/dead-code/unused-impl-for-non-adts.stderr
+++ /dev/null
@@ -1,20 +0,0 @@
-error: struct `Foo` is never constructed
-  --> $DIR/unused-impl-for-non-adts.rs:3:8
-   |
-LL | struct Foo;
-   |        ^^^
-   |
-note: the lint level is defined here
-  --> $DIR/unused-impl-for-non-adts.rs:1:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: trait `Trait` is never used
-  --> $DIR/unused-impl-for-non-adts.rs:5:7
-   |
-LL | trait Trait {
-   |       ^^^^^
-
-error: aborting due to 2 previous errors
-
diff --git a/tests/ui/lint/dead-code/unused-pub-struct.rs b/tests/ui/lint/dead-code/unused-pub-struct.rs
deleted file mode 100644
index aaf4dd612de..00000000000
--- a/tests/ui/lint/dead-code/unused-pub-struct.rs
+++ /dev/null
@@ -1,48 +0,0 @@
-#![deny(dead_code)]
-
-pub struct NotLint1(());
-pub struct NotLint2(std::marker::PhantomData<i32>);
-
-pub struct NeverConstructed(i32); //~ ERROR struct `NeverConstructed` is never constructed
-
-impl NeverConstructed {
-    pub fn not_construct_self(&self) {}
-}
-
-impl Clone for NeverConstructed {
-    fn clone(&self) -> NeverConstructed {
-        NeverConstructed(0)
-    }
-}
-
-pub trait Trait {
-    fn not_construct_self(&self);
-}
-
-impl Trait for NeverConstructed {
-    fn not_construct_self(&self) {
-        self.0;
-    }
-}
-
-pub struct Constructed(i32);
-
-impl Constructed {
-    pub fn construct_self() -> Self {
-        Constructed(0)
-    }
-}
-
-impl Clone for Constructed {
-    fn clone(&self) -> Constructed {
-        Constructed(0)
-    }
-}
-
-impl Trait for Constructed {
-    fn not_construct_self(&self) {
-        self.0;
-    }
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-pub-struct.stderr b/tests/ui/lint/dead-code/unused-pub-struct.stderr
deleted file mode 100644
index 3667ddb97bd..00000000000
--- a/tests/ui/lint/dead-code/unused-pub-struct.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: struct `NeverConstructed` is never constructed
-  --> $DIR/unused-pub-struct.rs:6:12
-   |
-LL | pub struct NeverConstructed(i32);
-   |            ^^^^^^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/unused-pub-struct.rs:1:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/lint/dead-code/unused-struct-derive-default.rs b/tests/ui/lint/dead-code/unused-struct-derive-default.rs
index f20b7cb66ee..330ad32dd57 100644
--- a/tests/ui/lint/dead-code/unused-struct-derive-default.rs
+++ b/tests/ui/lint/dead-code/unused-struct-derive-default.rs
@@ -22,5 +22,4 @@ pub struct T2 {
 
 fn main() {
     let _x: Used = Default::default();
-    let _e: E = Default::default();
 }
diff --git a/tests/ui/lint/dead-code/unused-struct-derive-default.stderr b/tests/ui/lint/dead-code/unused-struct-derive-default.stderr
index 7422f9a39f3..bbb0bd7be70 100644
--- a/tests/ui/lint/dead-code/unused-struct-derive-default.stderr
+++ b/tests/ui/lint/dead-code/unused-struct-derive-default.stderr
@@ -4,6 +4,7 @@ error: struct `T` is never constructed
 LL | struct T;
    |        ^
    |
+   = note: `T` has a derived impl for the trait `Default`, but this is intentionally ignored during dead code analysis
 note: the lint level is defined here
   --> $DIR/unused-struct-derive-default.rs:1:9
    |
diff --git a/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.rs b/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.rs
deleted file mode 100644
index e8116d83ebf..00000000000
--- a/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-#![deny(dead_code)]
-
-struct T1; //~ ERROR struct `T1` is never constructed
-
-trait Foo { type Unused; } //~ ERROR trait `Foo` is never used
-impl Foo for T1 { type Unused = Self; }
-
-pub trait Bar { type Used; }
-impl Bar for T1 { type Used = Self; }
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.stderr b/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.stderr
deleted file mode 100644
index ab73c640634..00000000000
--- a/tests/ui/lint/dead-code/unused-trait-with-assoc-ty.stderr
+++ /dev/null
@@ -1,20 +0,0 @@
-error: struct `T1` is never constructed
-  --> $DIR/unused-trait-with-assoc-ty.rs:3:8
-   |
-LL | struct T1;
-   |        ^^
-   |
-note: the lint level is defined here
-  --> $DIR/unused-trait-with-assoc-ty.rs:1:9
-   |
-LL | #![deny(dead_code)]
-   |         ^^^^^^^^^
-
-error: trait `Foo` is never used
-  --> $DIR/unused-trait-with-assoc-ty.rs:5:7
-   |
-LL | trait Foo { type Unused; }
-   |       ^^^
-
-error: aborting due to 2 previous errors
-
diff --git a/tests/ui/lint/unsafe_code/unsafe-extern-blocks.rs b/tests/ui/lint/unsafe_code/unsafe-extern-blocks.rs
index 6f2ead70db8..c264fa1c8da 100644
--- a/tests/ui/lint/unsafe_code/unsafe-extern-blocks.rs
+++ b/tests/ui/lint/unsafe_code/unsafe-extern-blocks.rs
@@ -1,4 +1,3 @@
-#![feature(unsafe_extern_blocks)]
 #![deny(unsafe_code)]
 
 #[allow(unsafe_code)]
diff --git a/tests/ui/lint/unsafe_code/unsafe-extern-blocks.stderr b/tests/ui/lint/unsafe_code/unsafe-extern-blocks.stderr
index 5439a311256..6d3b064da34 100644
--- a/tests/ui/lint/unsafe_code/unsafe-extern-blocks.stderr
+++ b/tests/ui/lint/unsafe_code/unsafe-extern-blocks.stderr
@@ -1,5 +1,5 @@
 error: usage of an `unsafe extern` block
-  --> $DIR/unsafe-extern-blocks.rs:9:1
+  --> $DIR/unsafe-extern-blocks.rs:8:1
    |
 LL | / unsafe extern "C" {
 LL | |
@@ -8,7 +8,7 @@ LL | | }
    | |_^
    |
 note: the lint level is defined here
-  --> $DIR/unsafe-extern-blocks.rs:2:9
+  --> $DIR/unsafe-extern-blocks.rs:1:9
    |
 LL | #![deny(unsafe_code)]
    |         ^^^^^^^^^^^
diff --git a/tests/ui/lint/wide_pointer_comparisons.stderr b/tests/ui/lint/wide_pointer_comparisons.stderr
index 81a221c0ee6..7fe382393d7 100644
--- a/tests/ui/lint/wide_pointer_comparisons.stderr
+++ b/tests/ui/lint/wide_pointer_comparisons.stderr
@@ -74,7 +74,7 @@ LL |     let _ = PartialEq::eq(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |     let _ = std::ptr::addr_eq(a, b);
-   |             ~~~~~~~~~~~~~~~~~~ ~  ~
+   |             ~~~~~~~~~~~~~~~~~~ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:35:13
@@ -85,7 +85,7 @@ LL |     let _ = PartialEq::ne(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |     let _ = !std::ptr::addr_eq(a, b);
-   |             ~~~~~~~~~~~~~~~~~~~ ~  ~
+   |             ~~~~~~~~~~~~~~~~~~~ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:37:13
@@ -96,7 +96,7 @@ LL |     let _ = a.eq(&b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |     let _ = std::ptr::addr_eq(a, b);
-   |             ++++++++++++++++++ ~  ~
+   |             ++++++++++++++++++ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:39:13
@@ -107,7 +107,7 @@ LL |     let _ = a.ne(&b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |     let _ = !std::ptr::addr_eq(a, b);
-   |             +++++++++++++++++++ ~  ~
+   |             +++++++++++++++++++ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:41:13
@@ -283,7 +283,7 @@ LL |         let _ = PartialEq::eq(a, b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = std::ptr::addr_eq(*a, *b);
-   |                 ~~~~~~~~~~~~~~~~~~~ ~~~ ~
+   |                 ~~~~~~~~~~~~~~~~~~~ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:85:17
@@ -294,7 +294,7 @@ LL |         let _ = PartialEq::ne(a, b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = !std::ptr::addr_eq(*a, *b);
-   |                 ~~~~~~~~~~~~~~~~~~~~ ~~~ ~
+   |                 ~~~~~~~~~~~~~~~~~~~~ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:87:17
@@ -305,7 +305,7 @@ LL |         let _ = PartialEq::eq(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = std::ptr::addr_eq(*a, *b);
-   |                 ~~~~~~~~~~~~~~~~~~~ ~~~ ~
+   |                 ~~~~~~~~~~~~~~~~~~~ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:89:17
@@ -316,7 +316,7 @@ LL |         let _ = PartialEq::ne(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = !std::ptr::addr_eq(*a, *b);
-   |                 ~~~~~~~~~~~~~~~~~~~~ ~~~ ~
+   |                 ~~~~~~~~~~~~~~~~~~~~ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:91:17
@@ -327,7 +327,7 @@ LL |         let _ = a.eq(b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = std::ptr::addr_eq(*a, *b);
-   |                 +++++++++++++++++++ ~~~ ~
+   |                 +++++++++++++++++++ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:93:17
@@ -338,7 +338,7 @@ LL |         let _ = a.ne(b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = !std::ptr::addr_eq(*a, *b);
-   |                 ++++++++++++++++++++ ~~~ ~
+   |                 ++++++++++++++++++++ ~~~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:95:17
@@ -519,11 +519,11 @@ LL |         let _ = PartialEq::eq(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = std::ptr::addr_eq(a, b);
-   |                 ~~~~~~~~~~~~~~~~~~ ~  ~
+   |                 ~~~~~~~~~~~~~~~~~~ ~
 help: use explicit `std::ptr::eq` method to compare metadata and addresses
    |
 LL |         let _ = std::ptr::eq(a, b);
-   |                 ~~~~~~~~~~~~~ ~  ~
+   |                 ~~~~~~~~~~~~~ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:133:17
@@ -534,11 +534,11 @@ LL |         let _ = PartialEq::ne(&a, &b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = !std::ptr::addr_eq(a, b);
-   |                 ~~~~~~~~~~~~~~~~~~~ ~  ~
+   |                 ~~~~~~~~~~~~~~~~~~~ ~
 help: use explicit `std::ptr::eq` method to compare metadata and addresses
    |
 LL |         let _ = !std::ptr::eq(a, b);
-   |                 ~~~~~~~~~~~~~~ ~  ~
+   |                 ~~~~~~~~~~~~~~ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:135:17
@@ -549,11 +549,11 @@ LL |         let _ = a.eq(&b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = std::ptr::addr_eq(a, b);
-   |                 ++++++++++++++++++ ~  ~
+   |                 ++++++++++++++++++ ~
 help: use explicit `std::ptr::eq` method to compare metadata and addresses
    |
 LL |         let _ = std::ptr::eq(a, b);
-   |                 +++++++++++++ ~  ~
+   |                 +++++++++++++ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:137:17
@@ -564,11 +564,11 @@ LL |         let _ = a.ne(&b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         let _ = !std::ptr::addr_eq(a, b);
-   |                 +++++++++++++++++++ ~  ~
+   |                 +++++++++++++++++++ ~
 help: use explicit `std::ptr::eq` method to compare metadata and addresses
    |
 LL |         let _ = !std::ptr::eq(a, b);
-   |                 ++++++++++++++ ~  ~
+   |                 ++++++++++++++ ~
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:142:9
@@ -594,7 +594,7 @@ LL |         cmp!(a, b);
 help: use `std::ptr::addr_eq` or untyped pointers to only compare their addresses
    |
 LL |         cmp!(std::ptr::addr_eq(a, b));
-   |              ++++++++++++++++++ ~  +
+   |              ++++++++++++++++++    +
 
 warning: ambiguous wide pointer comparison, the comparison includes metadata which may not be expected
   --> $DIR/wide_pointer_comparisons.rs:159:39
diff --git a/tests/ui/parser/issues/issue-105366.fixed b/tests/ui/parser/issues/issue-105366.fixed
index 95419dc07f2..7157b647524 100644
--- a/tests/ui/parser/issues/issue-105366.fixed
+++ b/tests/ui/parser/issues/issue-105366.fixed
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct Foo;
 
 impl From<i32> for Foo {
diff --git a/tests/ui/parser/issues/issue-105366.rs b/tests/ui/parser/issues/issue-105366.rs
index 3278b737991..dc3cb8b343d 100644
--- a/tests/ui/parser/issues/issue-105366.rs
+++ b/tests/ui/parser/issues/issue-105366.rs
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
 struct Foo;
 
 fn From<i32> for Foo {
diff --git a/tests/ui/parser/issues/issue-105366.stderr b/tests/ui/parser/issues/issue-105366.stderr
index 195305a2ec8..18c04dfaf20 100644
--- a/tests/ui/parser/issues/issue-105366.stderr
+++ b/tests/ui/parser/issues/issue-105366.stderr
@@ -1,5 +1,5 @@
 error: you might have meant to write `impl` instead of `fn`
-  --> $DIR/issue-105366.rs:6:1
+  --> $DIR/issue-105366.rs:5:1
    |
 LL | fn From<i32> for Foo {
    | ^^
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
index e9c89807fa5..a851300a982 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
@@ -1,8 +1,7 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub struct Example(usize)
+pub struct Example(#[allow(dead_code)] usize)
 where
     (): Sized;
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
index 3bd0f51ec2c..10f435859f1 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
@@ -1,11 +1,10 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
-#[allow(dead_code)]
 pub struct Example
 where
     (): Sized,
-(usize);
+(#[allow(dead_code)] usize);
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies
 
 struct _Demo
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
index 77eafa6bea3..ddbf237e866 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
@@ -1,23 +1,23 @@
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:6:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:5:1
    |
 LL |   pub struct Example
    |              ------- while parsing this tuple struct
 LL | / where
 LL | |     (): Sized,
    | |______________^ unexpected where clause
-LL |   (usize);
-   |   ------- the struct body
+LL |   (#[allow(dead_code)] usize);
+   |   --------------------------- the struct body
    |
 help: move the body before the where clause
    |
-LL ~ pub struct Example(usize)
+LL ~ pub struct Example(#[allow(dead_code)] usize)
 LL | where
 LL ~     (): Sized;
    |
 
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:12:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:11:1
    |
 LL |   struct _Demo
    |          ----- while parsing this tuple struct
diff --git a/tests/ui/parser/unsafe-foreign-mod-2.rs b/tests/ui/parser/unsafe-foreign-mod-2.rs
index 0b63a993c5b..6d339cd9088 100644
--- a/tests/ui/parser/unsafe-foreign-mod-2.rs
+++ b/tests/ui/parser/unsafe-foreign-mod-2.rs
@@ -1,8 +1,6 @@
 extern "C" unsafe {
     //~^ ERROR expected `{`, found keyword `unsafe`
-    //~| ERROR extern block cannot be declared unsafe
     unsafe fn foo();
-    //~^ ERROR items in unadorned `extern` blocks cannot have safety qualifiers
 }
 
 fn main() {}
diff --git a/tests/ui/parser/unsafe-foreign-mod-2.stderr b/tests/ui/parser/unsafe-foreign-mod-2.stderr
index 8bd592b5d43..0625e3362ed 100644
--- a/tests/ui/parser/unsafe-foreign-mod-2.stderr
+++ b/tests/ui/parser/unsafe-foreign-mod-2.stderr
@@ -4,21 +4,5 @@ error: expected `{`, found keyword `unsafe`
 LL | extern "C" unsafe {
    |            ^^^^^^ expected `{`
 
-error: extern block cannot be declared unsafe
-  --> $DIR/unsafe-foreign-mod-2.rs:1:12
-   |
-LL | extern "C" unsafe {
-   |            ^^^^^^
-   |
-   = note: see issue #123743 <https://github.com/rust-lang/rust/issues/123743> for more information
-   = help: add `#![feature(unsafe_extern_blocks)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/unsafe-foreign-mod-2.rs:4:5
-   |
-LL |     unsafe fn foo();
-   |     ^^^^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
diff --git a/tests/ui/parser/unsafe-foreign-mod.rs b/tests/ui/parser/unsafe-foreign-mod.rs
index eab134a4a4d..623c3bb81e4 100644
--- a/tests/ui/parser/unsafe-foreign-mod.rs
+++ b/tests/ui/parser/unsafe-foreign-mod.rs
@@ -1,5 +1,5 @@
-unsafe extern "C" {
-    //~^ ERROR extern block cannot be declared unsafe
-}
+//@ check-pass
+
+unsafe extern "C" {}
 
 fn main() {}
diff --git a/tests/ui/parser/unsafe-foreign-mod.stderr b/tests/ui/parser/unsafe-foreign-mod.stderr
deleted file mode 100644
index 60b918a89b3..00000000000
--- a/tests/ui/parser/unsafe-foreign-mod.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-error: extern block cannot be declared unsafe
-  --> $DIR/unsafe-foreign-mod.rs:1:1
-   |
-LL | unsafe extern "C" {
-   | ^^^^^^
-   |
-   = note: see issue #123743 <https://github.com/rust-lang/rust/issues/123743> for more information
-   = help: add `#![feature(unsafe_extern_blocks)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/pattern/issue-22546.rs b/tests/ui/pattern/issue-22546.rs
index d5c5b68be78..fd1d5fb6c47 100644
--- a/tests/ui/pattern/issue-22546.rs
+++ b/tests/ui/pattern/issue-22546.rs
@@ -15,7 +15,7 @@ impl<T: ::std::fmt::Display> Foo<T> {
     }
 }
 
-trait Tr {
+trait Tr { //~ WARN trait `Tr` is never used
     type U;
 }
 
diff --git a/tests/ui/pattern/issue-22546.stderr b/tests/ui/pattern/issue-22546.stderr
new file mode 100644
index 00000000000..e067a95e422
--- /dev/null
+++ b/tests/ui/pattern/issue-22546.stderr
@@ -0,0 +1,10 @@
+warning: trait `Tr` is never used
+  --> $DIR/issue-22546.rs:18:7
+   |
+LL | trait Tr {
+   |       ^^
+   |
+   = note: `#[warn(dead_code)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/privacy/issue-75907.stderr b/tests/ui/privacy/issue-75907.stderr
index f7cb874c2cc..3121cc04478 100644
--- a/tests/ui/privacy/issue-75907.stderr
+++ b/tests/ui/privacy/issue-75907.stderr
@@ -14,7 +14,7 @@ LL |     let Bar(x, y, Foo(z)) = make_bar();
 help: consider making the fields publicly accessible
    |
 LL |     pub(crate) struct Bar(pub u8, pub u8, pub Foo);
-   |                           ~~~     ~~~     +++
+   |                                   ~~~     +++
 
 error[E0532]: cannot match against a tuple struct which contains private fields
   --> $DIR/issue-75907.rs:15:19
diff --git a/tests/ui/privacy/privacy5.stderr b/tests/ui/privacy/privacy5.stderr
index 615b0af2762..ec3abe9b816 100644
--- a/tests/ui/privacy/privacy5.stderr
+++ b/tests/ui/privacy/privacy5.stderr
@@ -53,7 +53,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:56:12
@@ -262,7 +262,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:69:12
@@ -281,7 +281,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:70:12
@@ -300,7 +300,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:71:12
@@ -319,7 +319,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:72:18
@@ -338,7 +338,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:73:18
@@ -357,7 +357,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:74:18
@@ -376,7 +376,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:75:18
@@ -395,7 +395,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:83:17
@@ -452,7 +452,7 @@ LL |     pub struct C(pub isize, isize);
 help: consider making the fields publicly accessible
    |
 LL |     pub struct C(pub isize, pub isize);
-   |                  ~~~        +++
+   |                             +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:90:20
diff --git a/tests/ui/pub/pub-ident-struct-4.fixed b/tests/ui/pub/pub-ident-struct-4.fixed
index a62ece43ece..5fedbb72437 100644
--- a/tests/ui/pub/pub-ident-struct-4.fixed
+++ b/tests/ui/pub/pub-ident-struct-4.fixed
@@ -1,7 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub struct T(String);
+pub struct T(#[allow(dead_code)] String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}
diff --git a/tests/ui/pub/pub-ident-struct-4.rs b/tests/ui/pub/pub-ident-struct-4.rs
index 0d56a31beaf..5c721c25a78 100644
--- a/tests/ui/pub/pub-ident-struct-4.rs
+++ b/tests/ui/pub/pub-ident-struct-4.rs
@@ -1,7 +1,6 @@
 //@ run-rustfix
 
-#[allow(dead_code)]
-pub T(String);
+pub T(#[allow(dead_code)] String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}
diff --git a/tests/ui/pub/pub-ident-struct-4.stderr b/tests/ui/pub/pub-ident-struct-4.stderr
index d3072464e05..04965a1a737 100644
--- a/tests/ui/pub/pub-ident-struct-4.stderr
+++ b/tests/ui/pub/pub-ident-struct-4.stderr
@@ -1,12 +1,12 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-4.rs:4:1
+  --> $DIR/pub-ident-struct-4.rs:3:1
    |
-LL | pub T(String);
+LL | pub T(#[allow(dead_code)] String);
    | ^^^^^
    |
 help: add `struct` here to parse `T` as a struct
    |
-LL | pub struct T(String);
+LL | pub struct T(#[allow(dead_code)] String);
    |     ++++++
 
 error: aborting due to 1 previous error
diff --git a/tests/ui/regions/regions-issue-21422.rs b/tests/ui/regions/regions-issue-21422.rs
index 67852a6f5de..54beed9b3ac 100644
--- a/tests/ui/regions/regions-issue-21422.rs
+++ b/tests/ui/regions/regions-issue-21422.rs
@@ -5,7 +5,6 @@
 
 //@ pretty-expanded FIXME #23616
 
-#[allow(dead_code)]
 pub struct P<'a> {
     _ptr: *const &'a u8,
 }
diff --git a/tests/ui/rust-2024/safe-outside-extern.rs b/tests/ui/rust-2024/safe-outside-extern.rs
index 6773df5ef03..674b78dc571 100644
--- a/tests/ui/rust-2024/safe-outside-extern.rs
+++ b/tests/ui/rust-2024/safe-outside-extern.rs
@@ -1,29 +1,21 @@
-//@ revisions: gated ungated
-#![cfg_attr(gated, feature(unsafe_extern_blocks))]
-
 safe fn foo() {}
 //~^ ERROR: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
-//[ungated]~| ERROR: unsafe extern {}` blocks and `safe` keyword are experimental [E0658]
 
 safe static FOO: i32 = 1;
 //~^ ERROR: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
-//[ungated]~| ERROR: unsafe extern {}` blocks and `safe` keyword are experimental [E0658]
 
 trait Foo {
     safe fn foo();
     //~^ ERROR: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
-    //[ungated]~| ERROR: unsafe extern {}` blocks and `safe` keyword are experimental [E0658]
 }
 
 impl Foo for () {
     safe fn foo() {}
     //~^ ERROR: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
-    //[ungated]~| ERROR: unsafe extern {}` blocks and `safe` keyword are experimental [E0658]
 }
 
 type FnPtr = safe fn(i32, i32) -> i32;
 //~^ ERROR: function pointers cannot be declared with `safe` safety qualifier
-//[ungated]~| ERROR: unsafe extern {}` blocks and `safe` keyword are experimental [E0658]
 
 unsafe static LOL: u8 = 0;
 //~^ ERROR: static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
diff --git a/tests/ui/rust-2024/safe-outside-extern.stderr b/tests/ui/rust-2024/safe-outside-extern.stderr
new file mode 100644
index 00000000000..19d7c5fde0b
--- /dev/null
+++ b/tests/ui/rust-2024/safe-outside-extern.stderr
@@ -0,0 +1,38 @@
+error: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
+  --> $DIR/safe-outside-extern.rs:1:1
+   |
+LL | safe fn foo() {}
+   | ^^^^^^^^^^^^^^^^
+
+error: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
+  --> $DIR/safe-outside-extern.rs:4:1
+   |
+LL | safe static FOO: i32 = 1;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
+  --> $DIR/safe-outside-extern.rs:8:5
+   |
+LL |     safe fn foo();
+   |     ^^^^^^^^^^^^^^
+
+error: items outside of `unsafe extern { }` cannot be declared with `safe` safety qualifier
+  --> $DIR/safe-outside-extern.rs:13:5
+   |
+LL |     safe fn foo() {}
+   |     ^^^^^^^^^^^^^^^^
+
+error: function pointers cannot be declared with `safe` safety qualifier
+  --> $DIR/safe-outside-extern.rs:17:14
+   |
+LL | type FnPtr = safe fn(i32, i32) -> i32;
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+  --> $DIR/safe-outside-extern.rs:20:1
+   |
+LL | unsafe static LOL: u8 = 0;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
+
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2021.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2021.stderr
index 3a99caa719b..77554da10e6 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2021.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2021.stderr
@@ -1,5 +1,5 @@
 error[E0133]: call to unsafe function `test1` is unsafe and requires unsafe function or block
-  --> $DIR/extern-items-unsafe.rs:14:5
+  --> $DIR/extern-items-unsafe.rs:12:5
    |
 LL |     test1(TEST1);
    |     ^^^^^^^^^^^^ call to unsafe function
@@ -7,7 +7,7 @@ LL |     test1(TEST1);
    = note: consult the function's documentation for information on how to avoid undefined behavior
 
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/extern-items-unsafe.rs:14:11
+  --> $DIR/extern-items-unsafe.rs:12:11
    |
 LL |     test1(TEST1);
    |           ^^^^^ use of extern static
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2024.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2024.stderr
index fcf937b7ac5..33b752782d5 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2024.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.edition2024.stderr
@@ -1,5 +1,5 @@
 error[E0133]: call to unsafe function `test1` is unsafe and requires unsafe block
-  --> $DIR/extern-items-unsafe.rs:14:5
+  --> $DIR/extern-items-unsafe.rs:12:5
    |
 LL |     test1(TEST1);
    |     ^^^^^^^^^^^^ call to unsafe function
@@ -7,7 +7,7 @@ LL |     test1(TEST1);
    = note: consult the function's documentation for information on how to avoid undefined behavior
 
 error[E0133]: use of extern static is unsafe and requires unsafe block
-  --> $DIR/extern-items-unsafe.rs:14:11
+  --> $DIR/extern-items-unsafe.rs:12:11
    |
 LL |     test1(TEST1);
    |           ^^^^^ use of extern static
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.rs b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.rs
index ad569a256db..721e07acca5 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items-unsafe.rs
@@ -3,8 +3,6 @@
 //@[edition2024] edition:2024
 //@[edition2024] compile-flags: -Zunstable-options
 
-#![feature(unsafe_extern_blocks)]
-
 unsafe extern "C" {
     static TEST1: i32;
     fn test1(i: i32);
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.edition2024.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.edition2024.stderr
index d456cfc6829..8ef7c2caf21 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.edition2024.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.edition2024.stderr
@@ -1,5 +1,5 @@
 error: extern blocks must be unsafe
-  --> $DIR/extern-items.rs:9:1
+  --> $DIR/extern-items.rs:7:1
    |
 LL | / extern "C" {
 LL | |
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.rs b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.rs
index 16fa1bbb8a4..08805c36347 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/extern-items.rs
@@ -4,8 +4,6 @@
 //@[edition2024] edition:2024
 //@[edition2024] compile-flags: -Zunstable-options
 
-#![feature(unsafe_extern_blocks)]
-
 extern "C" {
     //[edition2024]~^ ERROR extern blocks must be unsafe
     static TEST1: i32;
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.rs b/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.rs
index 57c03e4d896..67df8c14b39 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.rs
@@ -1,6 +1,3 @@
-//@ revisions: gated ungated
-#![cfg_attr(gated, feature(unsafe_extern_blocks))]
-
 trait Bar {}
 safe impl Bar for () { }
 //~^ ERROR expected one of `!` or `::`, found keyword `impl`
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.gated.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.stderr
similarity index 83%
rename from tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.gated.stderr
rename to tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.stderr
index 80e7a45f57e..f1021726b18 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.gated.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-impl-trait.stderr
@@ -1,5 +1,5 @@
 error: expected one of `!` or `::`, found keyword `impl`
-  --> $DIR/safe-impl-trait.rs:5:6
+  --> $DIR/safe-impl-trait.rs:2:6
    |
 LL | safe impl Bar for () { }
    |      ^^^^ expected one of `!` or `::`
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-items.rs b/tests/ui/rust-2024/unsafe-extern-blocks/safe-items.rs
index 74cd5621fce..b0b8a8b012a 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-items.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-items.rs
@@ -4,8 +4,6 @@
 //@[edition2024] compile-flags: -Zunstable-options
 //@ check-pass
 
-#![feature(unsafe_extern_blocks)]
-
 unsafe extern "C" {
     safe static TEST1: i32;
     safe fn test1(i: i32);
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.rs b/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.rs
index e73cb45b188..52773b4cbbb 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.rs
@@ -1,6 +1,3 @@
-//@ revisions: gated ungated
-#![cfg_attr(gated, feature(unsafe_extern_blocks))]
-
 safe trait Foo {}
 //~^ ERROR expected one of `!` or `::`, found keyword `trait`
 
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.stderr
new file mode 100644
index 00000000000..1733336a797
--- /dev/null
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-trait.stderr
@@ -0,0 +1,8 @@
+error: expected one of `!` or `::`, found keyword `trait`
+  --> $DIR/safe-trait.rs:1:6
+   |
+LL | safe trait Foo {}
+   |      ^^^^^ expected one of `!` or `::`
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2021.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2021.stderr
index e90613357b1..93797987286 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2021.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2021.stderr
@@ -1,5 +1,5 @@
 error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:10:5
+  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:8:5
    |
 LL |     safe static TEST1: i32;
    |     ^^^^^^^^^^^^^^^^^^^^^^^
@@ -10,7 +10,7 @@ LL | unsafe extern "C" {
    | ++++++
 
 error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:12:5
+  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:10:5
    |
 LL |     safe fn test1(i: i32);
    |     ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2024.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2024.stderr
index 1207ee158cc..e9db6006c0b 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2024.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.edition2024.stderr
@@ -1,5 +1,5 @@
 error: extern blocks must be unsafe
-  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:8:1
+  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:6:1
    |
 LL | / extern "C" {
 LL | |
@@ -11,7 +11,7 @@ LL | | }
    | |_^
 
 error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:10:5
+  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:8:5
    |
 LL |     safe static TEST1: i32;
    |     ^^^^^^^^^^^^^^^^^^^^^^^
@@ -22,7 +22,7 @@ LL | unsafe extern "C" {
    | ++++++
 
 error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:12:5
+  --> $DIR/safe-unsafe-on-unadorned-extern-block.rs:10:5
    |
 LL |     safe fn test1(i: i32);
    |     ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.rs b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.rs
index 11f55cb195f..4badb50b267 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/safe-unsafe-on-unadorned-extern-block.rs
@@ -3,8 +3,6 @@
 //@[edition2024] edition:2024
 //@[edition2024] compile-flags: -Zunstable-options
 
-#![feature(unsafe_extern_blocks)]
-
 extern "C" {
     //[edition2024]~^ ERROR extern blocks must be unsafe
     safe static TEST1: i32;
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.fixed b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.fixed
index 10c19759d8a..f686809615f 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.fixed
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.fixed
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#![feature(unsafe_extern_blocks)]
 #![deny(missing_unsafe_on_extern)]
 #![allow(unused)]
 
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.rs b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.rs
index b81e52ddc58..00f1cbdab54 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.rs
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#![feature(unsafe_extern_blocks)]
 #![deny(missing_unsafe_on_extern)]
 #![allow(unused)]
 
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.stderr
index 0a3c2cd25e3..bb1d068ceb9 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-extern-suggestion.stderr
@@ -1,5 +1,5 @@
 error: extern blocks should be unsafe
-  --> $DIR/unsafe-extern-suggestion.rs:7:1
+  --> $DIR/unsafe-extern-suggestion.rs:6:1
    |
 LL |   extern "C" {
    |   ^
@@ -16,7 +16,7 @@ LL | | }
    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2024!
    = note: for more information, see issue #123743 <https://github.com/rust-lang/rust/issues/123743>
 note: the lint level is defined here
-  --> $DIR/unsafe-extern-suggestion.rs:4:9
+  --> $DIR/unsafe-extern-suggestion.rs:3:9
    |
 LL | #![deny(missing_unsafe_on_extern)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2021.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2021.stderr
index 8bb7ffefeea..e3626bb497e 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2021.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2021.stderr
@@ -1,5 +1,5 @@
 error[E0133]: call to unsafe function `test1` is unsafe and requires unsafe function or block
-  --> $DIR/unsafe-items.rs:20:5
+  --> $DIR/unsafe-items.rs:18:5
    |
 LL |     test1(TEST1);
    |     ^^^^^^^^^^^^ call to unsafe function
@@ -7,7 +7,7 @@ LL |     test1(TEST1);
    = note: consult the function's documentation for information on how to avoid undefined behavior
 
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/unsafe-items.rs:20:11
+  --> $DIR/unsafe-items.rs:18:11
    |
 LL |     test1(TEST1);
    |           ^^^^^ use of extern static
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2024.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2024.stderr
index 9a30142a632..89bc501b7b5 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2024.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.edition2024.stderr
@@ -1,5 +1,5 @@
 error[E0133]: call to unsafe function `test1` is unsafe and requires unsafe block
-  --> $DIR/unsafe-items.rs:20:5
+  --> $DIR/unsafe-items.rs:18:5
    |
 LL |     test1(TEST1);
    |     ^^^^^^^^^^^^ call to unsafe function
@@ -7,7 +7,7 @@ LL |     test1(TEST1);
    = note: consult the function's documentation for information on how to avoid undefined behavior
 
 error[E0133]: use of extern static is unsafe and requires unsafe block
-  --> $DIR/unsafe-items.rs:20:11
+  --> $DIR/unsafe-items.rs:18:11
    |
 LL |     test1(TEST1);
    |           ^^^^^ use of extern static
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.rs b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.rs
index 9066953abc6..dc2bae892a9 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-items.rs
@@ -3,8 +3,6 @@
 //@[edition2024] edition:2024
 //@[edition2024] compile-flags: -Zunstable-options
 
-#![feature(unsafe_extern_blocks)]
-
 unsafe extern "C" {
     unsafe static TEST1: i32;
     unsafe fn test1(i: i32);
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.fixed b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.fixed
index 2ff595cc44d..857d34eef85 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.fixed
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.fixed
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#![feature(unsafe_extern_blocks)]
 #![allow(dead_code)]
 
 unsafe extern "C" {
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.rs b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.rs
index 6fe43f7a5b4..edab9850d79 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.rs
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.rs
@@ -1,6 +1,5 @@
 //@ run-rustfix
 
-#![feature(unsafe_extern_blocks)]
 #![allow(dead_code)]
 
 extern "C" {
diff --git a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.stderr b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.stderr
index 05d23d001ad..073245e650b 100644
--- a/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.stderr
+++ b/tests/ui/rust-2024/unsafe-extern-blocks/unsafe-on-extern-block-issue-126756.stderr
@@ -1,5 +1,5 @@
 error: items in unadorned `extern` blocks cannot have safety qualifiers
-  --> $DIR/unsafe-on-extern-block-issue-126756.rs:7:5
+  --> $DIR/unsafe-on-extern-block-issue-126756.rs:6:5
    |
 LL |     unsafe fn foo();
    |     ^^^^^^^^^^^^^^^^
diff --git a/tests/ui/span/issue-42234-unknown-receiver-type.full.stderr b/tests/ui/span/issue-42234-unknown-receiver-type.full.stderr
index e01e1edab5a..6559845c23e 100644
--- a/tests/ui/span/issue-42234-unknown-receiver-type.full.stderr
+++ b/tests/ui/span/issue-42234-unknown-receiver-type.full.stderr
@@ -17,10 +17,6 @@ error[E0282]: type annotations needed
 LL |         .sum::<_>()
    |          ^^^ cannot infer type of the type parameter `S` declared on the method `sum`
    |
-help: consider specifying the generic argument
-   |
-LL |         .sum::<_>()
-   |             ~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/structs-enums/newtype-struct-with-dtor.rs b/tests/ui/structs-enums/newtype-struct-with-dtor.rs
index 16439a7fedd..19672e41c9a 100644
--- a/tests/ui/structs-enums/newtype-struct-with-dtor.rs
+++ b/tests/ui/structs-enums/newtype-struct-with-dtor.rs
@@ -3,10 +3,8 @@
 #![allow(unused_variables)]
 //@ pretty-expanded FIXME #23616
 
-#[allow(dead_code)]
 pub struct Fd(u32);
 
-#[allow(dead_code)]
 fn foo(a: u32) {}
 
 impl Drop for Fd {
diff --git a/tests/ui/structs-enums/uninstantiable-struct.rs b/tests/ui/structs-enums/uninstantiable-struct.rs
index 1074dbcd6e6..97bc7d8414e 100644
--- a/tests/ui/structs-enums/uninstantiable-struct.rs
+++ b/tests/ui/structs-enums/uninstantiable-struct.rs
@@ -1,5 +1,4 @@
 //@ run-pass
-#[allow(dead_code)]
-pub struct Z(&'static Z);
+pub struct Z(#[allow(dead_code)] &'static Z);
 
 pub fn main() {}
diff --git a/tests/ui/suggestions/derive-clone-for-eq.fixed b/tests/ui/suggestions/derive-clone-for-eq.fixed
index cf800c6e47d..4dc362f9478 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.fixed
+++ b/tests/ui/suggestions/derive-clone-for-eq.fixed
@@ -1,7 +1,6 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
-#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T: std::clone::Clone>(T);
 
diff --git a/tests/ui/suggestions/derive-clone-for-eq.rs b/tests/ui/suggestions/derive-clone-for-eq.rs
index 84736426bac..b3635000f16 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.rs
+++ b/tests/ui/suggestions/derive-clone-for-eq.rs
@@ -1,7 +1,6 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
-#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T>(T);
 
diff --git a/tests/ui/suggestions/derive-clone-for-eq.stderr b/tests/ui/suggestions/derive-clone-for-eq.stderr
index 54670fbffcf..6fae6e1316d 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.stderr
+++ b/tests/ui/suggestions/derive-clone-for-eq.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `T: Clone` is not satisfied
-  --> $DIR/derive-clone-for-eq.rs:5:17
+  --> $DIR/derive-clone-for-eq.rs:4:17
    |
 LL | #[derive(Clone, Eq)]
    |                 ^^ the trait `Clone` is not implemented for `T`, which is required by `Struct<T>: PartialEq`
    |
 note: required for `Struct<T>` to implement `PartialEq`
-  --> $DIR/derive-clone-for-eq.rs:8:19
+  --> $DIR/derive-clone-for-eq.rs:7:19
    |
 LL | impl<T: Clone, U> PartialEq<U> for Struct<T>
    |         -----     ^^^^^^^^^^^^     ^^^^^^^^^
diff --git a/tests/ui/suggestions/option-content-move.fixed b/tests/ui/suggestions/option-content-move.fixed
index ef07d55871e..4a5a9483c20 100644
--- a/tests/ui/suggestions/option-content-move.fixed
+++ b/tests/ui/suggestions/option-content-move.fixed
@@ -1,5 +1,4 @@
 //@ run-rustfix
-#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -18,7 +17,6 @@ impl LipogramCorpora {
     }
 }
 
-#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }
diff --git a/tests/ui/suggestions/option-content-move.rs b/tests/ui/suggestions/option-content-move.rs
index 5be6358fd6a..90d05c74399 100644
--- a/tests/ui/suggestions/option-content-move.rs
+++ b/tests/ui/suggestions/option-content-move.rs
@@ -1,5 +1,4 @@
 //@ run-rustfix
-#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -18,7 +17,6 @@ impl LipogramCorpora {
     }
 }
 
-#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }
diff --git a/tests/ui/suggestions/option-content-move.stderr b/tests/ui/suggestions/option-content-move.stderr
index b4ec5b180d2..a382a04344a 100644
--- a/tests/ui/suggestions/option-content-move.stderr
+++ b/tests/ui/suggestions/option-content-move.stderr
@@ -1,5 +1,5 @@
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:11:20
+  --> $DIR/option-content-move.rs:10:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
@@ -19,7 +19,7 @@ LL |                 if selection.1.clone().unwrap().contains(selection.0) {
    |                               ++++++++
 
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:30:20
+  --> $DIR/option-content-move.rs:28:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
diff --git a/tests/ui/suggestions/recover-missing-turbofish-surrounding-angle-braket.stderr b/tests/ui/suggestions/recover-missing-turbofish-surrounding-angle-braket.stderr
index 618ccba0d3d..dde6060c433 100644
--- a/tests/ui/suggestions/recover-missing-turbofish-surrounding-angle-braket.stderr
+++ b/tests/ui/suggestions/recover-missing-turbofish-surrounding-angle-braket.stderr
@@ -40,7 +40,7 @@ LL |     let _ = vec![1, 2, 3].into_iter().collect::Vec<_>>();
 help: surround the type parameters with angle brackets
    |
 LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<_>>();
-   |                                                +      ~
+   |                                                +
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/traits/object/generics.rs b/tests/ui/traits/object/generics.rs
index 0ae562c0d30..462b0bc5bb7 100644
--- a/tests/ui/traits/object/generics.rs
+++ b/tests/ui/traits/object/generics.rs
@@ -7,7 +7,6 @@ pub trait Trait2<A> {
     fn doit(&self) -> A;
 }
 
-#[allow(dead_code)]
 pub struct Impl<A1, A2, A3> {
     m1: marker::PhantomData<(A1,A2,A3)>,
     /*
diff --git a/tests/ui/unpretty/expanded-exhaustive.rs b/tests/ui/unpretty/expanded-exhaustive.rs
index 92c2e7b4884..29472df897a 100644
--- a/tests/ui/unpretty/expanded-exhaustive.rs
+++ b/tests/ui/unpretty/expanded-exhaustive.rs
@@ -25,7 +25,6 @@
 #![feature(trait_alias)]
 #![feature(try_blocks)]
 #![feature(unnamed_fields)]
-#![feature(unsafe_extern_blocks)]
 #![feature(yeet_expr)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/unpretty/expanded-exhaustive.stdout b/tests/ui/unpretty/expanded-exhaustive.stdout
index 137a8aa5510..cf2f6f8cbaa 100644
--- a/tests/ui/unpretty/expanded-exhaustive.stdout
+++ b/tests/ui/unpretty/expanded-exhaustive.stdout
@@ -26,7 +26,6 @@
 #![feature(trait_alias)]
 #![feature(try_blocks)]
 #![feature(unnamed_fields)]
-#![feature(unsafe_extern_blocks)]
 #![feature(yeet_expr)]
 #![allow(incomplete_features)]
 #[prelude_import]