Rollup merge of #124570 - nnethercote:misc-cleanups, r=michaelwoerister

Miscellaneous cleanups

A mix of small cleanups made while looking at various things.

r? `@wesleywiser`
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index a525b83..7b293e2 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -1,9 +1,3 @@
-/*!
-
-Rust MIR: a lowered representation of Rust.
-
-*/
-
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![feature(rustdoc_internals)]
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index 9958484..00bb4c4 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -1,21 +1,22 @@
+// tidy-alphabetical-start
+#![allow(internal_features)]
+#![allow(rustc::potential_query_instability)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
-#![feature(rustdoc_internals)]
-#![allow(internal_features)]
+#![feature(coroutines)]
 #![feature(decl_macro)]
 #![feature(error_iter)]
 #![feature(extract_if)]
-#![feature(coroutines)]
+#![feature(if_let_guard)]
 #![feature(iter_from_coroutine)]
 #![feature(let_chains)]
-#![feature(if_let_guard)]
-#![feature(proc_macro_internals)]
 #![feature(macro_metavar_expr)]
 #![feature(min_specialization)]
-#![feature(trusted_len)]
-#![feature(try_blocks)]
 #![feature(never_type)]
-#![allow(rustc::potential_query_instability)]
+#![feature(proc_macro_internals)]
+#![feature(rustdoc_internals)]
+#![feature(trusted_len)]
+// tidy-alphabetical-end
 
 extern crate proc_macro;
 
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 79e4ff8..825034c 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -1,15 +1,13 @@
 use crate::creader::CrateMetadataRef;
-use decoder::Metadata;
+pub(crate) use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
+use decoder::{DecodeContext, Metadata};
 use def_path_hash_map::DefPathHashMapRef;
-use rustc_data_structures::fx::FxHashMap;
-use rustc_macros::{Decodable, Encodable, TyDecodable, TyEncodable};
-use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
-use rustc_middle::middle::lib_features::FeatureStability;
-use table::TableBuilder;
-
+use encoder::EncodeContext;
+pub use encoder::{encode_metadata, rendered_const, EncodedMetadata};
 use rustc_ast as ast;
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_attr as attr;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::svh::Svh;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, DocLinkResMap};
@@ -18,10 +16,13 @@
 use rustc_hir::lang_items::LangItem;
 use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
+use rustc_macros::{Decodable, Encodable, TyDecodable, TyEncodable};
 use rustc_macros::{MetadataDecodable, MetadataEncodable};
 use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
+use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
+use rustc_middle::middle::lib_features::FeatureStability;
 use rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault;
 use rustc_middle::mir;
 use rustc_middle::trivially_parameterized_over_tcx;
@@ -33,20 +34,14 @@
 use rustc_session::config::SymbolManglingVersion;
 use rustc_session::cstore::{CrateDepKind, ForeignModule, LinkagePreference, NativeLib};
 use rustc_span::edition::Edition;
-use rustc_span::hygiene::{ExpnIndex, MacroKind};
+use rustc_span::hygiene::{ExpnIndex, MacroKind, SyntaxContextData};
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{self, ExpnData, ExpnHash, ExpnId, Span};
 use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
-
 use std::marker::PhantomData;
 use std::num::NonZero;
-
-use decoder::DecodeContext;
-pub(crate) use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
-use encoder::EncodeContext;
-pub use encoder::{encode_metadata, rendered_const, EncodedMetadata};
-use rustc_span::hygiene::SyntaxContextData;
+use table::TableBuilder;
 
 mod decoder;
 mod def_path_hash_map;
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 04fd4c8..70437fd 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -22,46 +22,46 @@
 //!
 //! This API is completely unstable and subject to change.
 
+// tidy-alphabetical-start
+#![allow(internal_features)]
+#![allow(rustc::diagnostic_outside_of_impl)]
+#![allow(rustc::potential_query_instability)]
+#![allow(rustc::untranslatable_diagnostic)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
-#![feature(min_exhaustive_patterns)]
-#![feature(rustdoc_internals)]
 #![feature(allocator_api)]
 #![feature(array_windows)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(closure_track_caller)]
-#![feature(core_intrinsics)]
+#![feature(const_option)]
 #![feature(const_type_name)]
-#![feature(discriminant_kind)]
+#![feature(core_intrinsics)]
 #![feature(coroutines)]
-#![feature(stmt_expr_attributes)]
+#![feature(decl_macro)]
+#![feature(discriminant_kind)]
+#![feature(extern_types)]
+#![feature(extract_if)]
 #![feature(if_let_guard)]
+#![feature(intra_doc_pointers)]
 #![feature(iter_from_coroutine)]
+#![feature(let_chains)]
+#![feature(macro_metavar_expr)]
+#![feature(min_exhaustive_patterns)]
+#![feature(min_specialization)]
 #![feature(negative_impls)]
 #![feature(never_type)]
-#![feature(extern_types)]
 #![feature(new_uninit)]
-#![feature(let_chains)]
-#![feature(min_specialization)]
-#![feature(trusted_len)]
-#![feature(type_alias_impl_trait)]
-#![feature(strict_provenance)]
-#![feature(rustc_attrs)]
-#![feature(control_flow_enum)]
-#![feature(trait_upcasting)]
-#![feature(try_blocks)]
-#![feature(decl_macro)]
-#![feature(extract_if)]
-#![feature(intra_doc_pointers)]
-#![feature(yeet_expr)]
-#![feature(const_option)]
 #![feature(ptr_alignment_type)]
-#![feature(macro_metavar_expr)]
-#![allow(internal_features)]
-#![allow(rustc::potential_query_instability)]
-#![allow(rustc::diagnostic_outside_of_impl)]
-#![allow(rustc::untranslatable_diagnostic)]
+#![feature(rustc_attrs)]
+#![feature(rustdoc_internals)]
+#![feature(strict_provenance)]
+#![feature(trait_upcasting)]
+#![feature(trusted_len)]
+#![feature(try_blocks)]
+#![feature(type_alias_impl_trait)]
+#![feature(yeet_expr)]
+// tidy-alphabetical-end
 
 #[macro_use]
 extern crate tracing;
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index aadbd74..b1438a5 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -42,12 +42,9 @@
 
 #[derive(LintDiagnostic)]
 #[diag(passes_diagnostic_diagnostic_on_unimplemented_only_for_traits)]
-pub struct DiagnosticOnUnimplementedOnlyForTraits;
+struct DiagnosticOnUnimplementedOnlyForTraits;
 
-pub(crate) fn target_from_impl_item<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    impl_item: &hir::ImplItem<'_>,
-) -> Target {
+fn target_from_impl_item<'tcx>(tcx: TyCtxt<'tcx>, impl_item: &hir::ImplItem<'_>) -> Target {
     match impl_item.kind {
         hir::ImplItemKind::Const(..) => Target::AssocConst,
         hir::ImplItemKind::Fn(..) => {
@@ -99,7 +96,7 @@
 }
 
 impl<'tcx> CheckAttrVisitor<'tcx> {
-    pub fn dcx(&self) -> &'tcx DiagCtxt {
+    fn dcx(&self) -> &'tcx DiagCtxt {
         self.tcx.dcx()
     }
 
diff --git a/compiler/rustc_passes/src/lang_items.rs b/compiler/rustc_passes/src/lang_items.rs
index a5fa94f..b3722e9 100644
--- a/compiler/rustc_passes/src/lang_items.rs
+++ b/compiler/rustc_passes/src/lang_items.rs
@@ -149,8 +149,9 @@
                 }
             };
 
-            // When there's a duplicate lang item, something went very wrong and there's no value in recovering or doing anything.
-            // Give the user the one message to let them debug the mess they created and then wish them farewell.
+            // When there's a duplicate lang item, something went very wrong and there's no value
+            // in recovering or doing anything. Give the user the one message to let them debug the
+            // mess they created and then wish them farewell.
             self.tcx.dcx().emit_fatal(DuplicateLangItem {
                 local_span: item_span,
                 lang_item_name,