Auto merge of #104170 - cjgillot:hir-def-id, r=fee1-dead

Record `LocalDefId` in HIR nodes instead of a side table

This is part of an attempt to remove the `HirId -> LocalDefId` table from HIR.
This attempt is a prerequisite to creation of `LocalDefId` after HIR lowering (#96840), by controlling how `def_id` information is accessed.

This first part adds the information to HIR nodes themselves instead of a table.
The second part is #103902
The third part will be to make `hir::Visitor::visit_fn` take a `LocalDefId` as last parameter.
The fourth part will be to completely remove the side table.

Author: bors

compiler/rustc_ast_lowering/src/expr.rs

@@ -643,6 +643,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // `static |_task_context| -> <ret_ty> { body }`:
         let generator_kind = {
             let c = self.arena.alloc(hir::Closure {
+                def_id: self.local_def_id(closure_node_id),
                 binder: hir::ClosureBinder::Default,
                 capture_clause,
                 bound_generic_params: &[],
@@ -895,6 +896,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let fn_decl = self.lower_fn_decl(decl, None, fn_decl_span, FnDeclKind::Closure, None);
 
         let c = self.arena.alloc(hir::Closure {
+            def_id: self.local_def_id(closure_id),
             binder: binder_clause,
             capture_clause,
             bound_generic_params,
@@ -999,6 +1001,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             self.lower_fn_decl(&outer_decl, None, fn_decl_span, FnDeclKind::Closure, None);
 
         let c = self.arena.alloc(hir::Closure {
+            def_id: self.local_def_id(closure_id),
             binder: binder_clause,
             capture_clause,
             bound_generic_params,

compiler/rustc_ast_lowering/src/index.rs

@@ -307,8 +307,8 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
     }
 
     fn visit_variant(&mut self, v: &'hir Variant<'hir>) {
-        self.insert(v.span, v.id, Node::Variant(v));
-        self.with_parent(v.id, |this| {
+        self.insert(v.span, v.hir_id, Node::Variant(v));
+        self.with_parent(v.hir_id, |this| {
             // Register the constructor of this variant.
             if let Some(ctor_hir_id) = v.data.ctor_hir_id() {
                 this.insert(v.span, ctor_hir_id, Node::Ctor(&v.data));

compiler/rustc_ast_lowering/src/item.rs

@@ -709,11 +709,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_variant(&mut self, v: &Variant) -> hir::Variant<'hir> {
-        let id = self.lower_node_id(v.id);
-        self.lower_attrs(id, &v.attrs);
+        let hir_id = self.lower_node_id(v.id);
+        self.lower_attrs(hir_id, &v.attrs);
         hir::Variant {
-            id,
-            data: self.lower_variant_data(id, &v.data),
+            hir_id,
+            def_id: self.local_def_id(v.id),
+            data: self.lower_variant_data(hir_id, &v.data),
             disr_expr: v.disr_expr.as_ref().map(|e| self.lower_anon_const(e)),
             ident: self.lower_ident(v.ident),
             span: self.lower_span(v.span),
@@ -739,12 +740,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         fields.iter().enumerate().map(|f| self.lower_field_def(f)),
                     ),
                     ctor_id,
+                    self.local_def_id(id),
                 )
             }
             VariantData::Unit(id) => {
                 let ctor_id = self.lower_node_id(id);
                 self.alias_attrs(ctor_id, parent_id);
-                hir::VariantData::Unit(ctor_id)
+                hir::VariantData::Unit(ctor_id, self.local_def_id(id))
             }
         }
     }
@@ -767,6 +769,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         hir::FieldDef {
             span: self.lower_span(f.span),
             hir_id,
+            def_id: self.local_def_id(f.id),
             ident: match f.ident {
                 Some(ident) => self.lower_ident(ident),
                 // FIXME(jseyfried): positional field hygiene.

compiler/rustc_ast_lowering/src/lib.rs

@@ -830,8 +830,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             ),
         };
         let hir_id = self.lower_node_id(node_id);
+        let def_id = self.local_def_id(node_id);
         Some(hir::GenericParam {
             hir_id,
+            def_id,
             name,
             span: self.lower_span(ident.span),
             pure_wrt_drop: false,
@@ -1165,7 +1167,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 let node_id = self.next_node_id();
 
                                 // Add a definition for the in-band const def.
-                                self.create_def(
+                                let def_id = self.create_def(
                                     parent_def_id.def_id,
                                     node_id,
                                     DefPathData::AnonConst,
@@ -1181,6 +1183,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 };
 
                                 let ct = self.with_new_scopes(|this| hir::AnonConst {
+                                    def_id,
                                     hir_id: this.lower_node_id(node_id),
                                     body: this.lower_const_body(path_expr.span, Some(&path_expr)),
                                 });
@@ -1528,6 +1531,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                         hir::GenericParam {
                             hir_id,
+                            def_id: lctx.local_def_id(new_node_id),
                             name,
                             span: lifetime.ident.span,
                             pure_wrt_drop: false,
@@ -1985,6 +1989,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                         hir::GenericParam {
                             hir_id,
+                            def_id: this.local_def_id(new_node_id),
                             name,
                             span: lifetime.ident.span,
                             pure_wrt_drop: false,
@@ -2183,6 +2188,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         self.lower_attrs(hir_id, &param.attrs);
         hir::GenericParam {
             hir_id,
+            def_id: self.local_def_id(param.id),
             name,
             span: self.lower_span(param.span()),
             pure_wrt_drop: self.tcx.sess.contains_name(&param.attrs, sym::may_dangle),
@@ -2287,6 +2293,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         // Set the name to `impl Bound1 + Bound2`.
         let param = hir::GenericParam {
             hir_id: self.lower_node_id(node_id),
+            def_id,
             name: ParamName::Plain(self.lower_ident(ident)),
             pure_wrt_drop: false,
             span: self.lower_span(span),
@@ -2347,6 +2354,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
     fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst {
         self.with_new_scopes(|this| hir::AnonConst {
+            def_id: this.local_def_id(c.id),
             hir_id: this.lower_node_id(c.id),
             body: this.lower_const_body(c.value.span, Some(&c.value)),
         })

compiler/rustc_borrowck/src/type_check/input_output.rs

@@ -42,8 +42,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             user_provided_sig = None;
         } else {
             let typeck_results = self.tcx().typeck(mir_def_id);
-            user_provided_sig = typeck_results.user_provided_sigs.get(&mir_def_id.to_def_id()).map(
-                |user_provided_poly_sig| {
+            user_provided_sig =
+                typeck_results.user_provided_sigs.get(&mir_def_id).map(|user_provided_poly_sig| {
                     // Instantiate the canonicalized variables from
                     // user-provided signature (e.g., the `_` in the code
                     // above) with fresh variables.
@@ -60,8 +60,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         LateBoundRegionConversionTime::FnCall,
                         poly_sig,
                     )
-                },
-            );
+                });
         }
 
         debug!(?normalized_input_tys, ?body.local_decls);

compiler/rustc_codegen_ssa/src/mono_item.rs

@@ -40,12 +40,12 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
                         .iter()
                         .map(|(op, op_sp)| match *op {
                             hir::InlineAsmOperand::Const { ref anon_const } => {
-                                let anon_const_def_id =
-                                    cx.tcx().hir().local_def_id(anon_const.hir_id).to_def_id();
-                                let const_value =
-                                    cx.tcx().const_eval_poly(anon_const_def_id).unwrap_or_else(
-                                        |_| span_bug!(*op_sp, "asm const cannot be resolved"),
-                                    );
+                                let const_value = cx
+                                    .tcx()
+                                    .const_eval_poly(anon_const.def_id.to_def_id())
+                                    .unwrap_or_else(|_| {
+                                        span_bug!(*op_sp, "asm const cannot be resolved")
+                                    });
                                 let ty = cx
                                     .tcx()
                                     .typeck_body(anon_const.body)

compiler/rustc_hir/src/hir.rs

@@ -487,6 +487,7 @@ pub enum GenericParamKind<'hir> {
 #[derive(Debug, HashStable_Generic)]
 pub struct GenericParam<'hir> {
     pub hir_id: HirId,
+    pub def_id: LocalDefId,
     pub name: ParamName,
     pub span: Span,
     pub pure_wrt_drop: bool,
@@ -921,6 +922,7 @@ pub struct Crate<'hir> {
 
 #[derive(Debug, HashStable_Generic)]
 pub struct Closure<'hir> {
+    pub def_id: LocalDefId,
     pub binder: ClosureBinder,
     pub capture_clause: CaptureBy,
     pub bound_generic_params: &'hir [GenericParam<'hir>],
@@ -1615,7 +1617,7 @@ pub enum ArrayLen {
 impl ArrayLen {
     pub fn hir_id(&self) -> HirId {
         match self {
-            &ArrayLen::Infer(hir_id, _) | &ArrayLen::Body(AnonConst { hir_id, body: _ }) => hir_id,
+            &ArrayLen::Infer(hir_id, _) | &ArrayLen::Body(AnonConst { hir_id, .. }) => hir_id,
         }
     }
 }
@@ -1627,10 +1629,11 @@ impl ArrayLen {
 /// explicit discriminant values for enum variants.
 ///
 /// You can check if this anon const is a default in a const param
-/// `const N: usize = { ... }` with `tcx.hir().opt_const_param_default_param_hir_id(..)`
+/// `const N: usize = { ... }` with `tcx.hir().opt_const_param_default_param_def_id(..)`
 #[derive(Copy, Clone, PartialEq, Eq, Encodable, Debug, HashStable_Generic)]
 pub struct AnonConst {
     pub hir_id: HirId,
+    pub def_id: LocalDefId,
     pub body: BodyId,
 }
 
@@ -2798,7 +2801,8 @@ pub struct Variant<'hir> {
     /// Name of the variant.
     pub ident: Ident,
     /// Id of the variant (not the constructor, see `VariantData::ctor_hir_id()`).
-    pub id: HirId,
+    pub hir_id: HirId,
+    pub def_id: LocalDefId,
     /// Fields and constructor id of the variant.
     pub data: VariantData<'hir>,
     /// Explicit discriminant (e.g., `Foo = 1`).
@@ -2865,6 +2869,7 @@ pub struct FieldDef<'hir> {
     pub vis_span: Span,
     pub ident: Ident,
     pub hir_id: HirId,
+    pub def_id: LocalDefId,
     pub ty: &'hir Ty<'hir>,
 }
 
@@ -2886,11 +2891,11 @@ pub enum VariantData<'hir> {
     /// A tuple variant.
     ///
     /// E.g., `Bar(..)` as in `enum Foo { Bar(..) }`.
-    Tuple(&'hir [FieldDef<'hir>], HirId),
+    Tuple(&'hir [FieldDef<'hir>], HirId, LocalDefId),
     /// A unit variant.
     ///
     /// E.g., `Bar = ..` as in `enum Foo { Bar = .. }`.
-    Unit(HirId),
+    Unit(HirId, LocalDefId),
 }
 
 impl<'hir> VariantData<'hir> {
@@ -2902,11 +2907,19 @@ impl<'hir> VariantData<'hir> {
         }
     }
 
+    /// Return the `LocalDefId` of this variant's constructor, if it has one.
+    pub fn ctor_def_id(&self) -> Option<LocalDefId> {
+        match *self {
+            VariantData::Struct(_, _) => None,
+            VariantData::Tuple(_, _, def_id) | VariantData::Unit(_, def_id) => Some(def_id),
+        }
+    }
+
     /// Return the `HirId` of this variant's constructor, if it has one.
     pub fn ctor_hir_id(&self) -> Option<HirId> {
         match *self {
             VariantData::Struct(_, _) => None,
-            VariantData::Tuple(_, hir_id) | VariantData::Unit(hir_id) => Some(hir_id),
+            VariantData::Tuple(_, hir_id, _) | VariantData::Unit(hir_id, _) => Some(hir_id),
         }
     }
 }
@@ -3532,7 +3545,7 @@ impl<'hir> Node<'hir> {
     /// Get the fields for the tuple-constructor,
     /// if this node is a tuple constructor, otherwise None
     pub fn tuple_fields(&self) -> Option<&'hir [FieldDef<'hir>]> {
-        if let Node::Ctor(&VariantData::Tuple(fields, _)) = self { Some(fields) } else { None }
+        if let Node::Ctor(&VariantData::Tuple(fields, _, _)) = self { Some(fields) } else { None }
     }
 }
 
@@ -3548,7 +3561,7 @@ mod size_asserts {
     static_assert_size!(FnDecl<'_>, 40);
     static_assert_size!(ForeignItem<'_>, 72);
     static_assert_size!(ForeignItemKind<'_>, 40);
-    static_assert_size!(GenericArg<'_>, 24);
+    static_assert_size!(GenericArg<'_>, 32);
     static_assert_size!(GenericBound<'_>, 48);
     static_assert_size!(Generics<'_>, 56);
     static_assert_size!(Impl<'_>, 80);

compiler/rustc_hir/src/intravisit.rs

@@ -733,6 +733,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             walk_list!(visitor, visit_arm, arms);
         }
         ExprKind::Closure(&Closure {
+            def_id: _,
             binder: _,
             bound_generic_params,
             fn_decl,
@@ -1084,7 +1085,7 @@ pub fn walk_enum_def<'v, V: Visitor<'v>>(
 
 pub fn walk_variant<'v, V: Visitor<'v>>(visitor: &mut V, variant: &'v Variant<'v>) {
     visitor.visit_ident(variant.ident);
-    visitor.visit_id(variant.id);
+    visitor.visit_id(variant.hir_id);
     visitor.visit_variant_data(&variant.data);
     walk_list!(visitor, visit_anon_const, &variant.disr_expr);
 }

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -432,7 +432,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         ty::Const::from_opt_const_arg_anon_const(
                             tcx,
                             ty::WithOptConstParam {
-                                did: tcx.hir().local_def_id(ct.value.hir_id),
+                                did: ct.value.def_id,
                                 const_param_did: Some(param.def_id),
                             },
                         )
@@ -570,8 +570,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             ConvertedBindingKind::Equality(self.ast_ty_to_ty(ty).into())
                         }
                         hir::Term::Const(ref c) => {
-                            let local_did = self.tcx().hir().local_def_id(c.hir_id);
-                            let c = Const::from_anon_const(self.tcx(), local_did);
+                            let c = Const::from_anon_const(self.tcx(), c.def_id);
                             ConvertedBindingKind::Equality(c.into())
                         }
                     },
@@ -856,7 +855,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         &self,
         bounds: &mut Bounds<'hir>,
         ast_bounds: &'hir [hir::GenericBound<'hir>],
-        self_ty_where_predicates: Option<(hir::HirId, &'hir [hir::WherePredicate<'hir>])>,
+        self_ty_where_predicates: Option<(LocalDefId, &'hir [hir::WherePredicate<'hir>])>,
         span: Span,
     ) {
         let tcx = self.tcx();
@@ -876,10 +875,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         };
         search_bounds(ast_bounds);
         if let Some((self_ty, where_clause)) = self_ty_where_predicates {
-            let self_ty_def_id = tcx.hir().local_def_id(self_ty).to_def_id();
             for clause in where_clause {
                 if let hir::WherePredicate::BoundPredicate(pred) = clause {
-                    if pred.is_param_bound(self_ty_def_id) {
+                    if pred.is_param_bound(self_ty.to_def_id()) {
                         search_bounds(pred.bounds);
                     }
                 }
@@ -2722,16 +2720,15 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 let length = match length {
                     &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span),
                     hir::ArrayLen::Body(constant) => {
-                        let length_def_id = tcx.hir().local_def_id(constant.hir_id);
-                        ty::Const::from_anon_const(tcx, length_def_id)
+                        ty::Const::from_anon_const(tcx, constant.def_id)
                     }
                 };
 
                 let array_ty = tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length));
                 self.normalize_ty(ast_ty.span, array_ty)
             }
             hir::TyKind::Typeof(ref e) => {
-                let ty_erased = tcx.type_of(tcx.hir().local_def_id(e.hir_id));
+                let ty_erased = tcx.type_of(e.def_id);
                 let ty = tcx.fold_regions(ty_erased, |r, _| {
                     if r.is_erased() { tcx.lifetimes.re_static } else { r }
                 });

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -853,7 +853,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) {
 
         // Const parameters are well formed if their type is structural match.
         hir::GenericParamKind::Const { ty: hir_ty, default: _ } => {
-            let ty = tcx.type_of(tcx.hir().local_def_id(param.hir_id));
+            let ty = tcx.type_of(param.def_id);
 
             if tcx.features().adt_const_params {
                 if let Some(non_structural_match_ty) =