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

clippy_lints/src/await_holding_invalid.rs

@@ -149,7 +149,7 @@ impl LateLintPass<'_> for AwaitHolding {
 fn check_interior_types(cx: &LateContext<'_>, ty_causes: &[GeneratorInteriorTypeCause<'_>], span: Span) {
     for ty_cause in ty_causes {
         if let rustc_middle::ty::Adt(adt, _) = ty_cause.ty.kind() {
-            if is_mutex_guard(cx, adt.did) {
+            if is_mutex_guard(cx, adt.did()) {
                 span_lint_and_then(
                     cx,
                     AWAIT_HOLDING_LOCK,
@@ -167,7 +167,7 @@ fn check_interior_types(cx: &LateContext<'_>, ty_causes: &[GeneratorInteriorType
                     },
                 );
             }
-            if is_refcell_ref(cx, adt.did) {
+            if is_refcell_ref(cx, adt.did()) {
                 span_lint_and_then(
                     cx,
                     AWAIT_HOLDING_REFCELL_REF,

clippy_lints/src/case_sensitive_file_extension_comparisons.rs

@@ -1,6 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
+use rustc_data_structures::intern::Interned;
 use rustc_hir::{Expr, ExprKind, PathSegment};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
@@ -55,7 +56,7 @@ fn check_case_sensitive_file_extension_comparison(ctx: &LateContext<'_>, expr: &
                 ty::Str => {
                     return Some(span);
                 },
-                ty::Adt(&ty::AdtDef { did, .. }, _) => {
+                ty::Adt(ty::AdtDef(Interned(&ty::AdtDefData { did, .. }, _)), _) => {
                     if ctx.tcx.is_diagnostic_item(sym::String, did) {
                         return Some(span);
                     }

clippy_lints/src/casts/cast_possible_truncation.rs

@@ -116,15 +116,15 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>,
                 && let Res::Def(DefKind::Ctor(..), id) = cx.qpath_res(p, cast_expr.hir_id)
             {
                 let i = def.variant_index_with_ctor_id(id);
-                let variant = &def.variants[i];
-                let nbits = utils::enum_value_nbits(get_discriminant_value(cx.tcx, def, i));
+                let variant = def.variant(i);
+                let nbits = utils::enum_value_nbits(get_discriminant_value(cx.tcx, *def, i));
                 (nbits, Some(variant))
             } else {
-                (utils::enum_ty_to_nbits(def, cx.tcx), None)
+                (utils::enum_ty_to_nbits(*def, cx.tcx), None)
             };
             let to_nbits = utils::int_ty_to_nbits(cast_to, cx.tcx);
 
-            let cast_from_ptr_size = def.repr.int.map_or(true, |ty| {
+            let cast_from_ptr_size = def.repr().int.map_or(true, |ty| {
                 matches!(
                     ty,
                     IntType::SignedInt(ast::IntTy::Isize) | IntType::UnsignedInt(ast::UintTy::Usize)

clippy_lints/src/casts/utils.rs

@@ -34,10 +34,10 @@ pub(super) fn enum_value_nbits(value: EnumValue) -> u64 {
     .into()
 }
 
-pub(super) fn enum_ty_to_nbits(adt: &AdtDef, tcx: TyCtxt<'_>) -> u64 {
+pub(super) fn enum_ty_to_nbits(adt: AdtDef<'_>, tcx: TyCtxt<'_>) -> u64 {
     let mut explicit = 0i128;
     let (start, end) = adt
-        .variants
+        .variants()
         .iter()
         .fold((0, i128::MIN), |(start, end), variant| match variant.discr {
             VariantDiscr::Relative(x) => match explicit.checked_add(i128::from(x)) {

clippy_lints/src/default.rs

@@ -96,7 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
             then {
                 // TODO: Work out a way to put "whatever the imported way of referencing
                 // this type in this file" rather than a fully-qualified type.
-                let replacement = format!("{}::default()", cx.tcx.def_path_str(def.did));
+                let replacement = format!("{}::default()", cx.tcx.def_path_str(def.did()));
                 span_lint_and_sugg(
                     cx,
                     DEFAULT_TRAIT_ACCESS,
@@ -137,7 +137,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
                 if let Some(adt) = binding_type.ty_adt_def();
                 if adt.is_struct();
                 let variant = adt.non_enum_variant();
-                if adt.did.is_local() || !variant.is_field_list_non_exhaustive();
+                if adt.did().is_local() || !variant.is_field_list_non_exhaustive();
                 let module_did = cx.tcx.parent_module(stmt.hir_id).to_def_id();
                 if variant
                     .fields
@@ -216,7 +216,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
                     if let ty::Adt(adt_def, substs) = binding_type.kind();
                     if !substs.is_empty();
                     then {
-                        let adt_def_ty_name = cx.tcx.item_name(adt_def.did);
+                        let adt_def_ty_name = cx.tcx.item_name(adt_def.did());
                         let generic_args = substs.iter().collect::<Vec<_>>();
                         let tys_str = generic_args
                             .iter()

clippy_lints/src/default_numeric_fallback.rs

@@ -148,7 +148,7 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
                 if_chain! {
                     if let Some(adt_def) = ty.ty_adt_def();
                     if adt_def.is_struct();
-                    if let Some(variant) = adt_def.variants.iter().next();
+                    if let Some(variant) = adt_def.variants().iter().next();
                     then {
                         let fields_def = &variant.fields;
 

clippy_lints/src/derivable_impls.rs

@@ -103,7 +103,7 @@ impl<'tcx> LateLintPass<'tcx> for DerivableImpls {
                     _ => false,
                 };
                 if should_emit {
-                    let path_string = cx.tcx.def_path_str(adt_def.did);
+                    let path_string = cx.tcx.def_path_str(adt_def.did());
                     span_lint_and_help(
                         cx,
                         DERIVABLE_IMPLS,

clippy_lints/src/derive.rs

@@ -315,7 +315,7 @@ fn check_copy_clone<'tcx>(cx: &LateContext<'tcx>, item: &Item<'_>, trait_ref: &T
             let has_copy_impl = cx.tcx.all_local_trait_impls(()).get(&copy_id).map_or(false, |impls| {
                 impls
                     .iter()
-                    .any(|&id| matches!(cx.tcx.type_of(id).kind(), ty::Adt(adt, _) if ty_adt.did == adt.did))
+                    .any(|&id| matches!(cx.tcx.type_of(id).kind(), ty::Adt(adt, _) if ty_adt.did() == adt.did()))
             });
             if !has_copy_impl {
                 return;
@@ -357,10 +357,10 @@ fn check_unsafe_derive_deserialize<'tcx>(
         if let Some(trait_def_id) = trait_ref.trait_def_id();
         if match_def_path(cx, trait_def_id, &paths::SERDE_DESERIALIZE);
         if let ty::Adt(def, _) = ty.kind();
-        if let Some(local_def_id) = def.did.as_local();
+        if let Some(local_def_id) = def.did().as_local();
         let adt_hir_id = cx.tcx.hir().local_def_id_to_hir_id(local_def_id);
         if !is_lint_allowed(cx, UNSAFE_DERIVE_DESERIALIZE, adt_hir_id);
-        if cx.tcx.inherent_impls(def.did)
+        if cx.tcx.inherent_impls(def.did())
             .iter()
             .map(|imp_did| cx.tcx.hir().expect_item(imp_did.expect_local()))
             .any(|imp| has_unsafe(cx, imp));

clippy_lints/src/empty_enum.rs

@@ -52,7 +52,7 @@ impl<'tcx> LateLintPass<'tcx> for EmptyEnum {
         if let ItemKind::Enum(..) = item.kind {
             let ty = cx.tcx.type_of(item.def_id);
             let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
-            if adt.variants.is_empty() {
+            if adt.variants().is_empty() {
                 span_lint_and_help(
                     cx,
                     EMPTY_ENUM,

clippy_lints/src/enum_clike.rs

@@ -55,7 +55,7 @@ impl<'tcx> LateLintPass<'tcx> for UnportableVariant {
                     if let Some(Constant::Int(val)) = constant.and_then(miri_to_const) {
                         if let ty::Adt(adt, _) = ty.kind() {
                             if adt.is_enum() {
-                                ty = adt.repr.discr_type().to_ty(cx.tcx);
+                                ty = adt.repr().discr_type().to_ty(cx.tcx);
                             }
                         }
                         match ty.kind() {