Rollup merge of #109716 - scottmcm:field-to-fieldidx, r=oli-obk

Move `mir::Field` → `abi::FieldIdx`

The first PR for https://github.com/rust-lang/compiler-team/issues/606

This is just the move-and-rename, because it's plenty big already.  Future PRs will start using `FieldIdx` more broadly, and concomitantly removing `FieldIdx::new`s.

compiler/rustc_middle/src/mir/mod.rs

@@ -21,7 +21,7 @@ use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
 use rustc_hir::{self, GeneratorKind, ImplicitSelfKind};
 use rustc_hir::{self as hir, HirId};
 use rustc_session::Session;
-use rustc_target::abi::{Size, VariantIdx};
+use rustc_target::abi::{FieldIdx, Size, VariantIdx};
 
 use polonius_engine::Atom;
 pub use rustc_ast::Mutability;
@@ -1512,7 +1512,7 @@ impl<V, T> ProjectionElem<V, T> {
     }
 
     /// Returns `true` if this is a `Field` projection with the given index.
-    pub fn is_field_to(&self, f: Field) -> bool {
+    pub fn is_field_to(&self, f: FieldIdx) -> bool {
         matches!(*self, Self::Field(x, _) if x == f)
     }
 }
@@ -1521,22 +1521,6 @@ impl<V, T> ProjectionElem<V, T> {
 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
 pub type ProjectionKind = ProjectionElem<(), ()>;
 
-rustc_index::newtype_index! {
-    /// A [newtype'd][wrapper] index type in the MIR [control-flow graph][CFG]
-    ///
-    /// A field (e.g., `f` in `_1.f`) is one variant of [`ProjectionElem`]. Conceptually,
-    /// rustc can identify that a field projection refers to either two different regions of memory
-    /// or the same one between the base and the 'projection element'.
-    /// Read more about projections in the [rustc-dev-guide][mir-datatypes]
-    ///
-    /// [wrapper]: https://rustc-dev-guide.rust-lang.org/appendix/glossary.html#newtype
-    /// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
-    /// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types
-    #[derive(HashStable)]
-    #[debug_format = "field[{}]"]
-    pub struct Field {}
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct PlaceRef<'tcx> {
     pub local: Local,
@@ -2685,12 +2669,17 @@ impl<'tcx> UserTypeProjections {
         self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
     }
 
-    pub fn leaf(self, field: Field) -> Self {
+    pub fn leaf(self, field: FieldIdx) -> Self {
         self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
     }
 
-    pub fn variant(self, adt_def: AdtDef<'tcx>, variant_index: VariantIdx, field: Field) -> Self {
-        self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
+    pub fn variant(
+        self,
+        adt_def: AdtDef<'tcx>,
+        variant_index: VariantIdx,
+        field_index: FieldIdx,
+    ) -> Self {
+        self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field_index))
     }
 }
 
@@ -2733,7 +2722,7 @@ impl UserTypeProjection {
         self
     }
 
-    pub(crate) fn leaf(mut self, field: Field) -> Self {
+    pub(crate) fn leaf(mut self, field: FieldIdx) -> Self {
         self.projs.push(ProjectionElem::Field(field, ()));
         self
     }
@@ -2742,13 +2731,13 @@ impl UserTypeProjection {
         mut self,
         adt_def: AdtDef<'_>,
         variant_index: VariantIdx,
-        field: Field,
+        field_index: FieldIdx,
     ) -> Self {
         self.projs.push(ProjectionElem::Downcast(
             Some(adt_def.variant(variant_index).name),
             variant_index,
         ));
-        self.projs.push(ProjectionElem::Field(field, ()));
+        self.projs.push(ProjectionElem::Field(field_index, ()));
         self
     }
 }

compiler/rustc_middle/src/mir/query.rs

@@ -10,12 +10,12 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_index::bit_set::BitMatrix;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_span::Span;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use smallvec::SmallVec;
 use std::cell::Cell;
 use std::fmt::{self, Debug};
 
-use super::{Field, SourceInfo};
+use super::SourceInfo;
 
 #[derive(Copy, Clone, PartialEq, TyEncodable, TyDecodable, HashStable, Debug)]
 pub enum UnsafetyViolationKind {
@@ -152,7 +152,7 @@ pub struct GeneratorLayout<'tcx> {
 
     /// Which of the above fields are in each variant. Note that one field may
     /// be stored in multiple variants.
-    pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
+    pub variant_fields: IndexVec<VariantIdx, IndexVec<FieldIdx, GeneratorSavedLocal>>,
 
     /// The source that led to each variant being created (usually, a yield or
     /// await).
@@ -229,7 +229,7 @@ pub struct BorrowCheckResult<'tcx> {
     /// unerased regions.
     pub concrete_opaque_types: FxIndexMap<LocalDefId, OpaqueHiddenType<'tcx>>,
     pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
-    pub used_mut_upvars: SmallVec<[Field; 8]>,
+    pub used_mut_upvars: SmallVec<[FieldIdx; 8]>,
     pub tainted_by_errors: Option<ErrorGuaranteed>,
 }
 
@@ -353,7 +353,7 @@ pub enum ConstraintCategory<'tcx> {
     /// like `Foo { field: my_val }`)
     Usage,
     OpaqueType,
-    ClosureUpvar(Field),
+    ClosureUpvar(FieldIdx),
 
     /// A constraint from a user-written predicate
     /// with the provided span, written on the item
@@ -375,7 +375,7 @@ pub enum ConstraintCategory<'tcx> {
 #[derive(TyEncodable, TyDecodable, HashStable, TypeVisitable, TypeFoldable)]
 pub enum ReturnConstraint {
     Normal,
-    ClosureUpvar(Field),
+    ClosureUpvar(FieldIdx),
 }
 
 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing

compiler/rustc_middle/src/mir/syntax.rs

@@ -3,7 +3,7 @@
 //! This is in a dedicated file so that changes to this file can be reviewed more carefully.
 //! The intention is that this file only contains datatype declarations, no code.
 
-use super::{BasicBlock, Constant, Field, Local, SwitchTargets, UserTypeProjection};
+use super::{BasicBlock, Constant, Local, SwitchTargets, UserTypeProjection};
 
 use crate::mir::coverage::{CodeRegion, CoverageKind};
 use crate::traits::Reveal;
@@ -16,7 +16,7 @@ use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{self as hir};
 use rustc_hir::{self, GeneratorKind};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 use rustc_ast::Mutability;
 use rustc_span::def_id::LocalDefId;
@@ -888,7 +888,15 @@ pub struct Place<'tcx> {
 #[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)]
 pub enum ProjectionElem<V, T> {
     Deref,
-    Field(Field, T),
+
+    /// A field (e.g., `f` in `_1.f`) is one variant of [`ProjectionElem`]. Conceptually,
+    /// rustc can identify that a field projection refers to either two different regions of memory
+    /// or the same one between the base and the 'projection element'.
+    /// Read more about projections in the [rustc-dev-guide][mir-datatypes]
+    ///
+    /// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types
+    Field(FieldIdx, T),
+
     /// Index into a slice/array.
     ///
     /// Note that this does not also dereference, and so it does not exactly correspond to slice

compiler/rustc_middle/src/mir/tcx.rs

@@ -6,7 +6,7 @@
 use crate::mir::*;
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_hir as hir;
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 
 #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
 pub struct PlaceTy<'tcx> {
@@ -33,7 +33,7 @@ impl<'tcx> PlaceTy<'tcx> {
     ///
     /// Note that the resulting type has not been normalized.
     #[instrument(level = "debug", skip(tcx), ret)]
-    pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: Field) -> Ty<'tcx> {
+    pub fn field_ty(self, tcx: TyCtxt<'tcx>, f: FieldIdx) -> Ty<'tcx> {
         match self.ty.kind() {
             ty::Adt(adt_def, substs) => {
                 let variant_def = match self.variant_index {
@@ -61,14 +61,14 @@ impl<'tcx> PlaceTy<'tcx> {
     /// `place_ty.projection_ty_core(tcx, elem, |...| { ... })`
     /// projects `place_ty` onto `elem`, returning the appropriate
     /// `Ty` or downcast variant corresponding to that projection.
-    /// The `handle_field` callback must map a `Field` to its `Ty`,
+    /// The `handle_field` callback must map a `FieldIdx` to its `Ty`,
     /// (which should be trivial when `T` = `Ty`).
     pub fn projection_ty_core<V, T>(
         self,
         tcx: TyCtxt<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
         elem: &ProjectionElem<V, T>,
-        mut handle_field: impl FnMut(&Self, Field, T) -> Ty<'tcx>,
+        mut handle_field: impl FnMut(&Self, FieldIdx, T) -> Ty<'tcx>,
         mut handle_opaque_cast: impl FnMut(&Self, T) -> Ty<'tcx>,
     ) -> PlaceTy<'tcx>
     where

compiler/rustc_middle/src/query/keys.rs

@@ -12,6 +12,7 @@ use rustc_hir::hir_id::{HirId, OwnerId};
 use rustc_query_system::query::{DefaultCacheSelector, SingleCacheSelector, VecCacheSelector};
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
+use rustc_target::abi::FieldIdx;
 
 /// Placeholder for `CrateNum`'s "local" counterpart
 #[derive(Copy, Clone, Debug)]
@@ -332,7 +333,7 @@ impl<'tcx> Key for (ty::ParamEnv<'tcx>, ty::PolyTraitRef<'tcx>) {
     }
 }
 
-impl<'tcx> Key for (ty::Const<'tcx>, mir::Field) {
+impl<'tcx> Key for (ty::Const<'tcx>, FieldIdx) {
     type CacheSelector = DefaultCacheSelector<Self>;
 
     fn default_span(&self, _: TyCtxt<'_>) -> Span {

compiler/rustc_middle/src/thir.rs

@@ -17,14 +17,14 @@ use rustc_index::newtype_index;
 use rustc_index::vec::IndexVec;
 use rustc_middle::middle::region;
 use rustc_middle::mir::interpret::AllocId;
-use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Field, Mutability, UnOp};
+use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Mutability, UnOp};
 use rustc_middle::ty::adjustment::PointerCast;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, AdtDef, FnSig, Ty, UpvarSubsts};
 use rustc_middle::ty::{CanonicalUserType, CanonicalUserTypeAnnotation};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{sym, Span, Symbol, DUMMY_SP};
-use rustc_target::abi::VariantIdx;
+use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_target::asm::InlineAsmRegOrRegClass;
 use std::fmt;
 use std::ops::Index;
@@ -366,7 +366,7 @@ pub enum ExprKind<'tcx> {
         /// Variant containing the field.
         variant_index: VariantIdx,
         /// This can be a named (`.foo`) or unnamed (`.0`) field.
-        name: Field,
+        name: FieldIdx,
     },
     /// A *non-overloaded* indexing operation.
     Index {
@@ -491,7 +491,7 @@ pub enum ExprKind<'tcx> {
 /// This is used in struct constructors.
 #[derive(Clone, Debug, HashStable)]
 pub struct FieldExpr {
-    pub name: Field,
+    pub name: FieldIdx,
     pub expr: ExprId,
 }
 
@@ -570,7 +570,7 @@ pub enum BindingMode {
 
 #[derive(Clone, Debug, HashStable)]
 pub struct FieldPat<'tcx> {
-    pub field: Field,
+    pub field: FieldIdx,
     pub pattern: Box<Pat<'tcx>>,
 }
 

compiler/rustc_middle/src/ty/context.rs

@@ -12,9 +12,7 @@ use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
 use crate::middle::resolve_bound_vars;
 use crate::middle::stability;
 use crate::mir::interpret::{self, Allocation, ConstAllocation};
-use crate::mir::{
-    Body, BorrowCheckResult, Field, Local, Place, PlaceElem, ProjectionKind, Promoted,
-};
+use crate::mir::{Body, BorrowCheckResult, Local, Place, PlaceElem, ProjectionKind, Promoted};
 use crate::query::LocalCrate;
 use crate::thir::Thir;
 use crate::traits;
@@ -65,7 +63,7 @@ use rustc_span::def_id::{DefPathHash, StableCrateId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::abi::{Layout, LayoutS, TargetDataLayout, VariantIdx};
+use rustc_target::abi::{FieldIdx, Layout, LayoutS, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 use rustc_type_ir::sty::TyKind::*;
 use rustc_type_ir::WithCachedTypeInfo;
@@ -2125,7 +2123,7 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
-    pub fn mk_place_field(self, place: Place<'tcx>, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
+    pub fn mk_place_field(self, place: Place<'tcx>, f: FieldIdx, ty: Ty<'tcx>) -> Place<'tcx> {
         self.mk_place_elem(place, PlaceElem::Field(f, ty))
     }
 

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -4,7 +4,7 @@
 //! to help with the tedium.
 
 use crate::mir::interpret;
-use crate::mir::{Field, ProjectionKind};
+use crate::mir::ProjectionKind;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
@@ -217,6 +217,7 @@ CloneLiftImpls! {
 // implementation and traversal implementations (the latter only for
 // TyCtxt<'_> interners).
 TrivialTypeTraversalAndLiftImpls! {
+    ::rustc_target::abi::FieldIdx,
     ::rustc_target::abi::VariantIdx,
     crate::middle::region::Scope,
     crate::ty::FloatTy,
@@ -268,7 +269,6 @@ TrivialTypeTraversalAndLiftImpls! {
     ::rustc_span::Span,
     ::rustc_span::symbol::Ident,
     ::rustc_errors::ErrorGuaranteed,
-    Field,
     interpret::Scalar,
     rustc_target::abi::Size,
     ty::BoundVar,