Rollup merge of rust-lang#118121 - nnethercote:rustc_hir, r=compiler-errors

`rustc_hir` cleanups

Just some improvements I found while looking at this code.

r? `@WaffleLapkin`

Author: Noratrieb

compiler/rustc_hir/src/arena.rs

@@ -5,7 +5,6 @@ macro_rules! arena_types {
     ($macro:path) => (
         $macro!([
             // HIR types
-            [] hir_krate: rustc_hir::Crate<'tcx>,
             [] asm_template: rustc_ast::InlineAsmTemplatePiece,
             [] attribute: rustc_ast::Attribute,
             [] owner_info: rustc_hir::OwnerInfo<'tcx>,

compiler/rustc_hir/src/def.rs

@@ -13,8 +13,7 @@ use std::array::IntoIter;
 use std::fmt::Debug;
 
 /// Encodes if a `DefKind::Ctor` is the constructor of an enum variant or a struct.
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
 pub enum CtorOf {
     /// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit struct.
     Struct,
@@ -23,8 +22,7 @@ pub enum CtorOf {
 }
 
 /// What kind of constructor something is.
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
 pub enum CtorKind {
     /// Constructor function automatically created by a tuple struct/variant.
     Fn,
@@ -33,8 +31,7 @@ pub enum CtorKind {
 }
 
 /// An attribute that is not a macro; e.g., `#[inline]` or `#[rustfmt::skip]`.
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
 pub enum NonMacroAttrKind {
     /// Single-segment attribute defined by the language (`#[inline]`)
     Builtin(Symbol),
@@ -48,8 +45,7 @@ pub enum NonMacroAttrKind {
 }
 
 /// What kind of definition something is; e.g., `mod` vs `struct`.
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
 pub enum DefKind {
     // Type namespace
     Mod,
@@ -299,8 +295,7 @@ impl DefKind {
 /// - the call to `str_to_string` will resolve to [`Res::Def`], with the [`DefId`]
 ///   pointing to the definition of `str_to_string` in the current crate.
 //
-#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug)]
-#[derive(HashStable_Generic)]
+#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
 pub enum Res<Id = hir::HirId> {
     /// Definition having a unique ID (`DefId`), corresponds to something defined in user code.
     ///
@@ -591,6 +586,8 @@ impl NonMacroAttrKind {
         }
     }
 
+    // Currently trivial, but exists in case a new kind is added in the future whose name starts
+    // with a vowel.
     pub fn article(self) -> &'static str {
         "a"
     }

compiler/rustc_hir/src/hir.rs

@@ -3,8 +3,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableOrd,
 use rustc_span::{def_id::DefPathHash, HashStableContext};
 use std::fmt::{self, Debug};
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
-#[derive(Encodable, Decodable)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)]
 pub struct OwnerId {
     pub def_id: LocalDefId,
 }
@@ -73,8 +72,7 @@ impl<CTX: HashStableContext> ToStableHashKey<CTX> for OwnerId {
 /// the `local_id` part of the `HirId` changing, which is a very useful property in
 /// incremental compilation where we have to persist things through changes to
 /// the code base.
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
-#[derive(Encodable, Decodable, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, HashStable_Generic)]
 #[rustc_pass_by_value]
 pub struct HirId {
     pub owner: OwnerId,

compiler/rustc_hir/src/hir_id.rs

@@ -233,7 +233,7 @@ language_item_table! {
     PanicFmt,                sym::panic_fmt,           panic_fmt,                  Target::Fn,             GenericRequirement::None;
     ConstPanicFmt,           sym::const_panic_fmt,     const_panic_fmt,            Target::Fn,             GenericRequirement::None;
     PanicBoundsCheck,        sym::panic_bounds_check,  panic_bounds_check_fn,      Target::Fn,             GenericRequirement::Exact(0);
-    PanicMisalignedPointerDereference,        sym::panic_misaligned_pointer_dereference,  panic_misaligned_pointer_dereference_fn,      Target::Fn,             GenericRequirement::Exact(0);
+    PanicMisalignedPointerDereference, sym::panic_misaligned_pointer_dereference, panic_misaligned_pointer_dereference_fn, Target::Fn, GenericRequirement::Exact(0);
     PanicInfo,               sym::panic_info,          panic_info,                 Target::Struct,         GenericRequirement::None;
     PanicLocation,           sym::panic_location,      panic_location,             Target::Struct,         GenericRequirement::None;
     PanicImpl,               sym::panic_impl,          panic_impl,                 Target::Fn,             GenericRequirement::None;

compiler/rustc_hir/src/lang_items.rs

@@ -4,7 +4,6 @@
 
 #![feature(associated_type_defaults)]
 #![feature(closure_track_caller)]
-#![feature(const_btree_len)]
 #![feature(let_chains)]
 #![feature(min_specialization)]
 #![feature(never_type)]

compiler/rustc_hir/src/lib.rs

@@ -27,19 +27,12 @@ macro_rules! arena_types {
                     rustc_middle::mir::Promoted,
                     rustc_middle::mir::Body<'tcx>
                 >,
-            [decode] closure_debuginfo:
-                rustc_index::IndexVec<
-                    rustc_target::abi::FieldIdx,
-                    rustc_span::symbol::Symbol,
-                >,
             [decode] typeck_results: rustc_middle::ty::TypeckResults<'tcx>,
-            [decode] borrowck_result:
-                rustc_middle::mir::BorrowCheckResult<'tcx>,
+            [decode] borrowck_result: rustc_middle::mir::BorrowCheckResult<'tcx>,
             [] resolver: rustc_data_structures::steal::Steal<(
                 rustc_middle::ty::ResolverAstLowering,
                 rustc_data_structures::sync::Lrc<rustc_ast::Crate>,
             )>,
-            [] output_filenames: std::sync::Arc<rustc_session::config::OutputFilenames>,
             [] crate_for_resolver: rustc_data_structures::steal::Steal<(rustc_ast::Crate, rustc_ast::AttrVec)>,
             [] resolutions: rustc_middle::ty::ResolverGlobalCtxt,
             [decode] unsafety_check_result: rustc_middle::mir::UnsafetyCheckResult,
@@ -91,29 +84,23 @@ macro_rules! arena_types {
                 rustc_middle::infer::canonical::Canonical<'tcx,
                     rustc_middle::infer::canonical::QueryResponse<'tcx, rustc_middle::ty::Ty<'tcx>>
                 >,
-            [] all_traits: Vec<rustc_hir::def_id::DefId>,
             [] effective_visibilities: rustc_middle::middle::privacy::EffectiveVisibilities,
-            [] foreign_module: rustc_session::cstore::ForeignModule,
-            [] foreign_modules: Vec<rustc_session::cstore::ForeignModule>,
             [] upvars_mentioned: rustc_data_structures::fx::FxIndexMap<rustc_hir::HirId, rustc_hir::Upvar>,
             [] object_safety_violations: rustc_middle::traits::ObjectSafetyViolation,
             [] codegen_unit: rustc_middle::mir::mono::CodegenUnit<'tcx>,
             [decode] attribute: rustc_ast::Attribute,
             [] name_set: rustc_data_structures::unord::UnordSet<rustc_span::symbol::Symbol>,
             [] ordered_name_set: rustc_data_structures::fx::FxIndexSet<rustc_span::symbol::Symbol>,
-            [] hir_id_set: rustc_hir::HirIdSet,
 
             // Interned types
             [] tys: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::TyKind<'tcx>>,
-            [] predicates: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::PredicateKind<'tcx>>,
             [] consts: rustc_middle::ty::ConstData<'tcx>,
 
             // Note that this deliberately duplicates items in the `rustc_hir::arena`,
             // since we need to allocate this type on both the `rustc_hir` arena
             // (during lowering) and the `librustc_middle` arena (for decoding MIR)
             [decode] asm_template: rustc_ast::InlineAsmTemplatePiece,
             [decode] used_trait_imports: rustc_data_structures::unord::UnordSet<rustc_hir::def_id::LocalDefId>,
-            [decode] registered_tools: rustc_middle::ty::RegisteredTools,
             [decode] is_late_bound_map: rustc_data_structures::fx::FxIndexSet<rustc_hir::ItemLocalId>,
             [decode] impl_source: rustc_middle::traits::ImplSource<'tcx, ()>,
 
@@ -124,11 +111,9 @@ macro_rules! arena_types {
                     rustc_hir::def_id::DefId,
                     rustc_middle::ty::EarlyBinder<rustc_middle::ty::Ty<'tcx>>
                 >,
-            [] bit_set_u32: rustc_index::bit_set::BitSet<u32>,
             [] external_constraints: rustc_middle::traits::solve::ExternalConstraintsData<'tcx>,
             [] predefined_opaques_in_body: rustc_middle::traits::solve::PredefinedOpaquesData<'tcx>,
             [decode] doc_link_resolutions: rustc_hir::def::DocLinkResMap,
-            [] closure_kind_origin: (rustc_span::Span, rustc_middle::hir::place::Place<'tcx>),
             [] stripped_cfg_items: rustc_ast::expand::StrippedCfgItem,
             [] mod_child: rustc_middle::metadata::ModChild,
             [] features: rustc_feature::Features,