Clean up trivial traversal/lift impl generator macro calls.

We have four macros for generating trivial traversal (fold/visit) and
lift impls.
- `rustc_ir::TrivialTypeTraversalImpls`
- `rustc_middle::TrivialTypeTraversalImpls`
- `rustc_middle::TrivialLiftImpls`
- `rustc_middle::TrivialTypeTraversalAndLiftImpls`

The first two are very similar. The last one just combines the second
and third one.

The macros themselves are ok, but their use is a mess. This commit does
the following.
- Removes types that no longer need a lift and/or traversal impl from
  the macro calls.
- Consolidates the macro calls into the smallest number of calls
  possible, with each one mentioning as many types as possible.
- Orders the types within those macro calls alphabetically, and makes
  the module qualification more consistent.
- Eliminates `rustc_middle::mir::type_foldable`, because the macro calls
  were merged and the manual `TypeFoldable` impls are better placed in
  `structural_impls.rs`, alongside all the other ones.

This makes the code more concise. Moving forward, it also makes it more
obvious where new types should be added.

Author: nnethercote

compiler/rustc_middle/src/infer/canonical.rs

@@ -142,10 +142,6 @@ impl<'tcx, R> QueryResponse<'tcx, R> {
 pub type QueryOutlivesConstraint<'tcx> =
     (ty::OutlivesPredicate<'tcx, GenericArg<'tcx>>, ConstraintCategory<'tcx>);
 
-TrivialTypeTraversalImpls! {
-    crate::infer::canonical::Certainty,
-}
-
 #[derive(Default)]
 pub struct CanonicalParamEnvCache<'tcx> {
     map: Lock<

compiler/rustc_middle/src/mir/basic_blocks.rs

@@ -163,6 +163,7 @@ impl<'tcx> graph::Predecessors for BasicBlocks<'tcx> {
     }
 }
 
+// Done here instead of in `structural_impls.rs` because `Cache` is private, as is `basic_blocks`.
 TrivialTypeTraversalImpls! { Cache }
 
 impl<S: Encoder> Encodable<S> for Cache {

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -95,8 +95,6 @@ impl From<ReportedErrorInfo> for ErrorGuaranteed {
     }
 }
 
-TrivialTypeTraversalImpls! { ErrorHandled }
-
 pub type EvalToAllocationRawResult<'tcx> = Result<ConstAlloc<'tcx>, ErrorHandled>;
 pub type EvalStaticInitializerRawResult<'tcx> = Result<ConstAllocation<'tcx>, ErrorHandled>;
 pub type EvalToConstValueResult<'tcx> = Result<ConstValue<'tcx>, ErrorHandled>;

compiler/rustc_middle/src/mir/mod.rs

@@ -34,7 +34,6 @@ use self::visit::TyContext;
 use crate::mir::interpret::{AllocRange, Scalar};
 use crate::mir::visit::MirVisitable;
 use crate::ty::codec::{TyDecoder, TyEncoder};
-use crate::ty::fold::{FallibleTypeFolder, TypeFoldable};
 use crate::ty::print::{FmtPrinter, Printer, pretty_print_const, with_no_trimmed_paths};
 use crate::ty::visit::TypeVisitableExt;
 use crate::ty::{
@@ -59,7 +58,6 @@ pub mod tcx;
 mod terminator;
 
 pub mod traversal;
-mod type_foldable;
 pub mod visit;
 
 pub use consts::*;
@@ -927,8 +925,6 @@ pub enum BindingForm<'tcx> {
     RefForGuard,
 }
 
-TrivialTypeTraversalImpls! { BindingForm<'tcx> }
-
 mod binding_form_impl {
     use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
     use rustc_query_system::ich::StableHashingContext;

compiler/rustc_middle/src/mir/type_foldable.rs

@@ -427,10 +427,6 @@ pub enum IsConstable {
     Ctor,
 }
 
-TrivialTypeTraversalAndLiftImpls! {
-    IsConstable,
-}
-
 /// The 'location' at which we try to perform HIR-based wf checking.
 /// This information is used to obtain an `hir::Ty`, which
 /// we can walk in order to obtain precise spans for any

compiler/rustc_middle/src/traits/mod.rs

@@ -260,8 +260,6 @@ impl From<ErrorGuaranteed> for OverflowError {
     }
 }
 
-TrivialTypeTraversalImpls! { OverflowError }
-
 impl<'tcx> From<OverflowError> for SelectionError<'tcx> {
     fn from(overflow_error: OverflowError) -> SelectionError<'tcx> {
         match overflow_error {

compiler/rustc_middle/src/traits/select.rs

@@ -30,8 +30,6 @@ impl From<ErrorGuaranteed> for NotConstEvaluatable {
     }
 }
 
-TrivialTypeTraversalImpls! { NotConstEvaluatable }
-
 pub type BoundAbstractConst<'tcx> =
     Result<Option<EarlyBinder<'tcx, ty::Const<'tcx>>>, ErrorGuaranteed>;
 

compiler/rustc_middle/src/ty/abstract_const.rs

@@ -76,11 +76,11 @@ use crate::traits::solve::{
 };
 use crate::ty::predicate::ExistentialPredicateStableCmpExt as _;
 use crate::ty::{
-    self, AdtDef, AdtDefData, AdtKind, Binder, BoundConstness, Clause, Clauses, Const, GenericArg,
-    GenericArgs, GenericArgsRef, GenericParamDefKind, ImplPolarity, List, ListWithCachedTypeInfo,
-    ParamConst, ParamTy, Pattern, PatternKind, PolyExistentialPredicate, PolyFnSig, Predicate,
-    PredicateKind, PredicatePolarity, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty,
-    TyKind, TyVid, Visibility,
+    self, AdtDef, AdtDefData, AdtKind, Binder, Clause, Clauses, Const, GenericArg, GenericArgs,
+    GenericArgsRef, GenericParamDefKind, List, ListWithCachedTypeInfo, ParamConst, ParamTy,
+    Pattern, PatternKind, PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind,
+    PredicatePolarity, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVid,
+    Visibility,
 };
 
 #[allow(rustc::usage_of_ty_tykind)]
@@ -2279,10 +2279,6 @@ macro_rules! nop_slice_lift {
 
 nop_slice_lift! {ty::ValTree<'a> => ty::ValTree<'tcx>}
 
-TrivialLiftImpls! {
-    ImplPolarity, PredicatePolarity, Promoted, BoundConstness,
-}
-
 macro_rules! sty_debug_print {
     ($fmt: expr, $ctxt: expr, $($variant: ident),*) => {{
         // Curious inner module to allow variant names to be used as

compiler/rustc_middle/src/ty/context.rs

@@ -6,15 +6,18 @@
 use std::fmt::{self, Debug};
 
 use rustc_abi::TyAndLayout;
+use rustc_ast::InlineAsmTemplatePiece;
 use rustc_ast_ir::try_visit;
 use rustc_ast_ir::visit::VisitorResult;
 use rustc_hir::def::Namespace;
+use rustc_hir::def_id::LocalDefId;
+use rustc_span::Span;
 use rustc_span::source_map::Spanned;
 use rustc_type_ir::ConstKind;
 
 use super::print::PrettyPrinter;
 use super::{GenericArg, GenericArgKind, Pattern, Region};
-use crate::mir::interpret;
+use crate::mir::PlaceElem;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{FmtPrinter, Printer, with_no_trimmed_paths};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
@@ -221,76 +224,83 @@ impl<'tcx> fmt::Debug for Region<'tcx> {
 // copy...), just add them to one of these lists as appropriate.
 
 // For things for which the type library provides traversal implementations
-// for all Interners, we only need to provide a Lift implementation:
+// for all Interners, we only need to provide a Lift implementation.
 TrivialLiftImpls! {
-     (),
-     bool,
-     usize,
-     u64,
+    (),
+    bool,
+    usize,
+    u64,
+    crate::mir::Promoted,
+    crate::mir::interpret::AllocId,
+    crate::mir::interpret::Scalar,
+    rustc_abi::ExternAbi,
+    rustc_abi::Size,
+    rustc_hir::Safety,
+    rustc_type_ir::BoundConstness,
+    rustc_type_ir::PredicatePolarity,
 }
 
 // For some things about which the type library does not know, or does not
 // provide any traversal implementations, we need to provide a traversal
 // implementation (only for TyCtxt<'_> interners).
 TrivialTypeTraversalImpls! {
-    ::rustc_abi::FieldIdx,
-    ::rustc_abi::VariantIdx,
-    crate::middle::region::Scope,
-    ::rustc_ast::InlineAsmOptions,
-    ::rustc_ast::InlineAsmTemplatePiece,
-    ::rustc_ast::NodeId,
-    ::rustc_hir::def::Res,
-    ::rustc_hir::def_id::LocalDefId,
-    ::rustc_hir::ByRef,
-    ::rustc_hir::HirId,
-    ::rustc_hir::MatchSource,
-    ::rustc_target::asm::InlineAsmRegOrRegClass,
-    crate::mir::coverage::BlockMarkerId,
-    crate::mir::coverage::CounterId,
-    crate::mir::coverage::ExpressionId,
-    crate::mir::coverage::ConditionId,
+    crate::infer::canonical::Certainty,
+    crate::mir::BasicBlock,
+    crate::mir::BindingForm<'tcx>,
+    crate::mir::BlockTailInfo,
+    crate::mir::BorrowKind,
+    crate::mir::CastKind,
+    crate::mir::ConstValue<'tcx>,
+    crate::mir::CoroutineSavedLocal,
+    crate::mir::FakeReadCause,
     crate::mir::Local,
+    crate::mir::MirPhase,
+    crate::mir::NullOp<'tcx>,
     crate::mir::Promoted,
-    crate::ty::adjustment::AutoBorrowMutability,
+    crate::mir::RawPtrKind,
+    crate::mir::RetagKind,
+    crate::mir::SourceInfo,
+    crate::mir::SourceScope,
+    crate::mir::SourceScopeLocalData,
+    crate::mir::SwitchTargets,
+    crate::traits::IsConstable,
+    crate::traits::OverflowError,
     crate::ty::AdtKind,
-    crate::ty::BoundRegion,
-    // Including `BoundRegionKind` is a *bit* dubious, but direct
-    // references to bound region appear in `ty::Error`, and aren't
-    // really meant to be folded. In general, we can only fold a fully
-    // general `Region`.
-    crate::ty::BoundRegionKind,
     crate::ty::AssocItem,
     crate::ty::AssocKind,
+    crate::ty::BoundRegion,
+    crate::ty::BoundVar,
     crate::ty::Placeholder<crate::ty::BoundRegion>,
     crate::ty::Placeholder<crate::ty::BoundTy>,
     crate::ty::Placeholder<ty::BoundVar>,
-    crate::ty::LateParamRegion,
+    crate::ty::UserTypeAnnotationIndex,
+    crate::ty::ValTree<'tcx>,
+    crate::ty::abstract_const::NotConstEvaluatable,
+    crate::ty::adjustment::AutoBorrowMutability,
     crate::ty::adjustment::PointerCoercion,
-    ::rustc_span::Ident,
-    ::rustc_span::Span,
-    ::rustc_span::Symbol,
-    ty::BoundVar,
-    ty::ValTree<'tcx>,
+    rustc_abi::FieldIdx,
+    rustc_abi::VariantIdx,
+    rustc_ast::InlineAsmOptions,
+    rustc_ast::InlineAsmTemplatePiece,
+    rustc_hir::CoroutineKind,
+    rustc_hir::HirId,
+    rustc_hir::MatchSource,
+    rustc_hir::def_id::LocalDefId,
+    rustc_span::Ident,
+    rustc_span::Span,
+    rustc_span::Symbol,
+    rustc_target::asm::InlineAsmRegOrRegClass,
 }
+
 // For some things about which the type library does not know, or does not
 // provide any traversal implementations, we need to provide a traversal
 // implementation and a lift implementation (the former only for TyCtxt<'_>
 // interners).
 TrivialTypeTraversalAndLiftImpls! {
-    ::rustc_hir::def_id::DefId,
-    crate::ty::ClosureKind,
     crate::ty::ParamConst,
     crate::ty::ParamTy,
     crate::ty::instance::ReifyReason,
-    interpret::AllocId,
-    interpret::CtfeProvenance,
-    interpret::Scalar,
-    rustc_abi::Size,
-}
-
-TrivialLiftImpls! {
-    ::rustc_hir::Safety,
-    ::rustc_abi::ExternAbi,
+    rustc_hir::def_id::DefId,
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -672,3 +682,39 @@ impl<'tcx, T: TypeFoldable<TyCtxt<'tcx>> + Debug + Clone> TypeFoldable<TyCtxt<'t
         })
     }
 }
+
+impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx [InlineAsmTemplatePiece] {
+    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
+        self,
+        _folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        Ok(self)
+    }
+}
+
+impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx [Span] {
+    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
+        self,
+        _folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        Ok(self)
+    }
+}
+
+impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<LocalDefId> {
+    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
+        self,
+        _folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        Ok(self)
+    }
+}
+
+impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx ty::List<PlaceElem<'tcx>> {
+    fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
+        self,
+        folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        ty::util::fold_list(self, folder, |tcx, v| tcx.mk_place_elems(v))
+    }
+}

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -47,23 +47,14 @@ TrivialTypeTraversalImpls! {
     u16,
     u32,
     u64,
-    String,
     crate::AliasRelationDirection,
-    crate::AliasTyKind,
     crate::BoundConstness,
     crate::DebruijnIndex,
-    crate::FloatTy,
-    crate::InferTy,
-    crate::IntVarValue,
     crate::PredicatePolarity,
-    crate::RegionVid,
+    crate::UniverseIndex,
+    crate::Variance,
     crate::solve::BuiltinImplSource,
     crate::solve::Certainty,
     crate::solve::GoalSource,
-    crate::solve::MaybeCause,
-    crate::solve::NoSolution,
-    crate::UniverseIndex,
-    crate::Variance,
-    rustc_ast_ir::Movability,
     rustc_ast_ir::Mutability,
 }