Improve AdtDef interning.

This commit makes `AdtDef` use `Interned`. Much the commit is tedious
changes to introduce getter functions. The interesting changes are in
`compiler/rustc_middle/src/ty/adt.rs`.

Author: nnethercote

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -138,7 +138,7 @@ impl BorrowExplanation {
                 let mut ty = local_decl.ty;
                 if local_decl.source_info.span.desugaring_kind() == Some(DesugaringKind::ForLoop) {
                     if let ty::Adt(adt, substs) = local_decl.ty.kind() {
-                        if tcx.is_diagnostic_item(sym::Option, adt.did) {
+                        if tcx.is_diagnostic_item(sym::Option, adt.did()) {
                             // in for loop desugaring, only look at the `Some(..)` inner type
                             ty = substs.type_at(0);
                         }
@@ -148,7 +148,7 @@ impl BorrowExplanation {
                     // If type is an ADT that implements Drop, then
                     // simplify output by reporting just the ADT name.
                     ty::Adt(adt, _substs) if adt.has_dtor(tcx) && !adt.is_box() => {
-                        ("`Drop` code", format!("type `{}`", tcx.def_path_str(adt.did)))
+                        ("`Drop` code", format!("type `{}`", tcx.def_path_str(adt.did())))
                     }
 
                     // Otherwise, just report the whole type (and use

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -370,7 +370,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 ty::Adt(def, _) => {
                     let variant = if let Some(idx) = variant_index {
                         assert!(def.is_enum());
-                        &def.variants[idx]
+                        &def.variant(idx)
                     } else {
                         def.non_enum_variant()
                     };
@@ -701,7 +701,7 @@ impl<'tcx> BorrowedContentSource<'tcx> {
             BorrowedContentSource::DerefMutableRef => "a mutable reference".to_string(),
             BorrowedContentSource::OverloadedDeref(ty) => ty
                 .ty_adt_def()
-                .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
+                .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? {
                     name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
                     _ => None,
                 })
@@ -731,7 +731,7 @@ impl<'tcx> BorrowedContentSource<'tcx> {
             }
             BorrowedContentSource::OverloadedDeref(ty) => ty
                 .ty_adt_def()
-                .and_then(|adt| match tcx.get_diagnostic_name(adt.did)? {
+                .and_then(|adt| match tcx.get_diagnostic_name(adt.did())? {
                     name @ (sym::Rc | sym::Arc) => Some(format!("an `{}`", name)),
                     _ => None,
                 })

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -388,7 +388,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         };
         let ty = move_place.ty(self.body, self.infcx.tcx).ty;
         let def_id = match *ty.kind() {
-            ty::Adt(self_def, _) => self_def.did,
+            ty::Adt(self_def, _) => self_def.did(),
             ty::Foreign(def_id)
             | ty::FnDef(def_id, _)
             | ty::Closure(def_id, _)

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -345,8 +345,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     ty::Adt(adt, substs) => {
                         let generic_arg = substs[param_index as usize];
                         let identity_substs =
-                            InternalSubsts::identity_for_item(self.infcx.tcx, adt.did);
-                        let base_ty = self.infcx.tcx.mk_adt(adt, identity_substs);
+                            InternalSubsts::identity_for_item(self.infcx.tcx, adt.did());
+                        let base_ty = self.infcx.tcx.mk_adt(*adt, identity_substs);
                         let base_generic_arg = identity_substs[param_index as usize];
                         let adt_desc = adt.descr();
 
@@ -410,7 +410,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 "returns a closure that contains a reference to a captured variable, which then \
                  escapes the closure body"
             }
-            ty::Adt(def, _) if self.infcx.tcx.is_diagnostic_item(sym::gen_future, def.did) => {
+            ty::Adt(def, _) if self.infcx.tcx.is_diagnostic_item(sym::gen_future, def.did()) => {
                 "returns an `async` block that contains a reference to a captured variable, which then \
                  escapes the closure body"
             }

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -736,13 +736,13 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
             }
             ProjectionElem::Downcast(maybe_name, index) => match base_ty.kind() {
                 ty::Adt(adt_def, _substs) if adt_def.is_enum() => {
-                    if index.as_usize() >= adt_def.variants.len() {
+                    if index.as_usize() >= adt_def.variants().len() {
                         PlaceTy::from_ty(span_mirbug_and_err!(
                             self,
                             place,
                             "cast to variant #{:?} but enum only has {:?}",
                             index,
-                            adt_def.variants.len()
+                            adt_def.variants().len()
                         ))
                     } else {
                         PlaceTy { ty: base_ty, variant_index: Some(index) }
@@ -816,7 +816,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
 
         let (variant, substs) = match base_ty {
             PlaceTy { ty, variant_index: Some(variant_index) } => match *ty.kind() {
-                ty::Adt(adt_def, substs) => (&adt_def.variants[variant_index], substs),
+                ty::Adt(adt_def, substs) => (adt_def.variant(variant_index), substs),
                 ty::Generator(def_id, substs, _) => {
                     let mut variants = substs.as_generator().state_tys(def_id, tcx);
                     let Some(mut variant) = variants.nth(variant_index.into()) else {
@@ -835,7 +835,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
             },
             PlaceTy { ty, variant_index: None } => match *ty.kind() {
                 ty::Adt(adt_def, substs) if !adt_def.is_enum() => {
-                    (&adt_def.variants[VariantIdx::new(0)], substs)
+                    (adt_def.variant(VariantIdx::new(0)), substs)
                 }
                 ty::Closure(_, substs) => {
                     return match substs
@@ -1449,7 +1449,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         );
                     }
                 };
-                if variant_index.as_usize() >= adt.variants.len() {
+                if variant_index.as_usize() >= adt.variants().len() {
                     span_bug!(
                         stmt.source_info.span,
                         "bad set discriminant ({:?} = {:?}): value of of range",
@@ -1928,7 +1928,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         match *ak {
             AggregateKind::Adt(adt_did, variant_index, substs, _, active_field_index) => {
                 let def = tcx.adt_def(adt_did);
-                let variant = &def.variants[variant_index];
+                let variant = &def.variant(variant_index);
                 let adj_field_index = active_field_index.unwrap_or(field_index);
                 if let Some(field) = variant.fields.get(adj_field_index) {
                     Ok(self.normalize(field.ty(tcx, substs), location))

compiler/rustc_codegen_cranelift/src/common.rs

@@ -67,7 +67,7 @@ fn clif_type_from_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Option<types::Typ
                 pointer_ty(tcx)
             }
         }
-        ty::Adt(adt_def, _) if adt_def.repr.simd() => {
+        ty::Adt(adt_def, _) if adt_def.repr().simd() => {
             let (element, count) = match &tcx.layout_of(ParamEnv::reveal_all().and(ty)).unwrap().abi
             {
                 Abi::Vector { element, count } => (element.clone(), *count),

compiler/rustc_codegen_cranelift/src/unsize.rs

@@ -127,7 +127,7 @@ pub(crate) fn coerce_unsized_into<'tcx>(
         (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
             assert_eq!(def_a, def_b);
 
-            for i in 0..def_a.variants[VariantIdx::new(0)].fields.len() {
+            for i in 0..def_a.variant(VariantIdx::new(0)).fields.len() {
                 let src_f = src.value_field(fx, mir::Field::new(i));
                 let dst_f = dst.place_field(fx, mir::Field::new(i));
 
@@ -200,7 +200,7 @@ pub(crate) fn size_and_align_of_dst<'tcx>(
 
             // Packed types ignore the alignment of their fields.
             if let ty::Adt(def, _) = layout.ty.kind() {
-                if def.repr.packed() {
+                if def.repr().packed() {
                     unsized_align = sized_align;
                 }
             }

compiler/rustc_codegen_cranelift/src/value_and_place.rs

@@ -24,7 +24,7 @@ fn codegen_field<'tcx>(
         }
         match field_layout.ty.kind() {
             ty::Slice(..) | ty::Str | ty::Foreign(..) => simple(fx),
-            ty::Adt(def, _) if def.repr.packed() => {
+            ty::Adt(def, _) if def.repr().packed() => {
                 assert_eq!(layout.align.abi.bytes(), 1);
                 simple(fx)
             }
@@ -816,7 +816,7 @@ pub(crate) fn assert_assignable<'tcx>(
             // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
         }
         (&ty::Adt(adt_def_a, substs_a), &ty::Adt(adt_def_b, substs_b))
-            if adt_def_a.did == adt_def_b.did =>
+            if adt_def_a.did() == adt_def_b.did() =>
         {
             let mut types_a = substs_a.types();
             let mut types_b = substs_b.types();

compiler/rustc_codegen_gcc/src/type_of.rs

@@ -56,8 +56,8 @@ pub fn uncached_gcc_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, layout: TyAndLa
             if let (&ty::Adt(def, _), &Variants::Single { index }) =
                 (layout.ty.kind(), &layout.variants)
             {
-                if def.is_enum() && !def.variants.is_empty() {
-                    write!(&mut name, "::{}", def.variants[index].name).unwrap();
+                if def.is_enum() && !def.variants().is_empty() {
+                    write!(&mut name, "::{}", def.variant(index).name).unwrap();
                 }
             }
             if let (&ty::Generator(_, _, _), &Variants::Single { index }) =

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -639,7 +639,7 @@ pub fn type_metadata<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll
             AdtKind::Struct => prepare_struct_metadata(cx, t, unique_type_id).finalize(cx),
             AdtKind::Union => prepare_union_metadata(cx, t, unique_type_id).finalize(cx),
             AdtKind::Enum => {
-                prepare_enum_metadata(cx, t, def.did, unique_type_id, vec![]).finalize(cx)
+                prepare_enum_metadata(cx, t, def.did(), unique_type_id, vec![]).finalize(cx)
             }
         },
         ty::Tuple(tys) => {
@@ -1207,7 +1207,7 @@ fn prepare_struct_metadata<'ll, 'tcx>(
     let struct_name = compute_debuginfo_type_name(cx.tcx, struct_type, false);
 
     let (struct_def_id, variant) = match struct_type.kind() {
-        ty::Adt(def, _) => (def.did, def.non_enum_variant()),
+        ty::Adt(def, _) => (def.did(), def.non_enum_variant()),
         _ => bug!("prepare_struct_metadata on a non-ADT"),
     };
 
@@ -1384,7 +1384,7 @@ fn prepare_union_metadata<'ll, 'tcx>(
     let union_name = compute_debuginfo_type_name(cx.tcx, union_type, false);
 
     let (union_def_id, variant) = match union_type.kind() {
-        ty::Adt(def, _) => (def.did, def.non_enum_variant()),
+        ty::Adt(def, _) => (def.did(), def.non_enum_variant()),
         _ => bug!("prepare_union_metadata on a non-ADT"),
     };
 
@@ -1466,7 +1466,7 @@ impl<'ll, 'tcx> EnumMemberDescriptionFactory<'ll, 'tcx> {
         };
 
         let variant_info_for = |index: VariantIdx| match *self.enum_type.kind() {
-            ty::Adt(adt, _) => VariantInfo::Adt(&adt.variants[index], index),
+            ty::Adt(adt, _) => VariantInfo::Adt(&adt.variant(index), index),
             ty::Generator(def_id, _, _) => {
                 let (generator_layout, generator_saved_local_names) =
                     generator_variant_info_data.as_ref().unwrap();
@@ -1490,7 +1490,7 @@ impl<'ll, 'tcx> EnumMemberDescriptionFactory<'ll, 'tcx> {
         match self.layout.variants {
             Variants::Single { index } => {
                 if let ty::Adt(adt, _) = self.enum_type.kind() {
-                    if adt.variants.is_empty() {
+                    if adt.variants().is_empty() {
                         return vec![];
                     }
                 }
@@ -1940,7 +1940,7 @@ fn prepare_enum_metadata<'ll, 'tcx>(
 
     let discriminant_type_metadata = |discr: Primitive| {
         let enumerators_metadata: Vec<_> = match enum_type.kind() {
-            ty::Adt(def, _) => iter::zip(def.discriminants(tcx), &def.variants)
+            ty::Adt(def, _) => iter::zip(def.discriminants(tcx), def.variants())
                 .map(|((_, discr), v)| {
                     let name = v.name.as_str();
                     let is_unsigned = match discr.ty.kind() {
@@ -2311,7 +2311,7 @@ fn set_members_of_composite_type<'ll, 'tcx>(
 fn compute_type_parameters<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> &'ll DIArray {
     if let ty::Adt(def, substs) = *ty.kind() {
         if substs.types().next().is_some() {
-            let generics = cx.tcx.generics_of(def.did);
+            let generics = cx.tcx.generics_of(def.did());
             let names = get_parameter_names(cx, generics);
             let template_params: Vec<_> = iter::zip(substs, names)
                 .filter_map(|(kind, name)| {