resolve: Remove struct_field_names_untracked

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -30,7 +30,6 @@ use rustc_session::cstore::{
 };
 use rustc_session::Session;
 use rustc_span::hygiene::ExpnIndex;
-use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, Ident, Symbol};
 use rustc_span::{self, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
 
@@ -1134,20 +1133,6 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .decode((self, sess))
     }
 
-    fn get_struct_field_names(
-        self,
-        id: DefIndex,
-        sess: &'a Session,
-    ) -> impl Iterator<Item = Spanned<Symbol>> + 'a {
-        self.root
-            .tables
-            .children
-            .get(self, id)
-            .expect("fields not encoded for a struct")
-            .decode(self)
-            .map(move |index| respan(self.get_span(index, sess), self.item_name(index)))
-    }
-
     fn get_inherent_implementations_for_type(
         self,
         tcx: TyCtxt<'tcx>,

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -19,8 +19,8 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::cstore::{CrateSource, CrateStore};
 use rustc_session::{Session, StableCrateId};
 use rustc_span::hygiene::{ExpnHash, ExpnId};
-use rustc_span::source_map::{Span, Spanned};
 use rustc_span::symbol::{kw, Symbol};
+use rustc_span::Span;
 
 use rustc_data_structures::sync::Lrc;
 use std::any::Any;
@@ -507,14 +507,6 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
 }
 
 impl CStore {
-    pub fn struct_field_names_untracked<'a>(
-        &'a self,
-        def: DefId,
-        sess: &'a Session,
-    ) -> impl Iterator<Item = Spanned<Symbol>> + 'a {
-        self.get_crate_data(def.krate).get_struct_field_names(def.index, sess)
-    }
-
     pub fn ctor_untracked(&self, def: DefId) -> Option<(CtorKind, DefId)> {
         self.get_crate_data(def.krate).get_ctor(def.index)
     }

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -29,7 +29,6 @@ use rustc_middle::metadata::ModChild;
 use rustc_middle::{bug, ty};
 use rustc_session::cstore::CrateStore;
 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind};
-use rustc_span::source_map::respan;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::Span;
 
@@ -327,13 +326,13 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
         }
     }
 
-    fn insert_field_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
+    fn insert_field_def_ids(&mut self, def_id: LocalDefId, vdata: &ast::VariantData) {
-        let field_names = vdata
+        if vdata.fields().iter().any(|field| field.is_placeholder) {
-            .fields()
+            // The fields are not expanded yet.
-            .iter()
+            return;
-            .map(|field| respan(field.span, field.ident.map_or(kw::Empty, |ident| ident.name)))
+        }
-            .collect();
+        let def_ids = vdata.fields().iter().map(|field| self.r.local_def_id(field.id).to_def_id());
-        self.r.field_names.insert(def_id, field_names);
+        self.r.field_def_ids.insert(def_id, self.r.tcx.arena.alloc_from_iter(def_ids));
     }
 
     fn insert_field_visibilities_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
@@ -345,12 +344,6 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
         self.r.field_visibility_spans.insert(def_id, field_vis);
     }
 
-    fn insert_field_names_extern(&mut self, def_id: DefId) {
-        let field_names =
-            self.r.cstore().struct_field_names_untracked(def_id, self.r.tcx.sess).collect();
-        self.r.field_names.insert(def_id, field_names);
-    }
-
     fn block_needs_anonymous_module(&mut self, block: &Block) -> bool {
         // If any statements are items, we need to create an anonymous module
         block
@@ -748,7 +741,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
 
                 // Record field names for error reporting.
-                self.insert_field_names_local(def_id, vdata);
+                self.insert_field_def_ids(local_def_id, vdata);
                 self.insert_field_visibilities_local(def_id, vdata);
 
                 // If this is a tuple or unit struct, define a name
@@ -797,7 +790,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                 self.r.define(parent, ident, TypeNS, (res, vis, sp, expansion));
 
                 // Record field names for error reporting.
-                self.insert_field_names_local(def_id, vdata);
+                self.insert_field_def_ids(local_def_id, vdata);
                 self.insert_field_visibilities_local(def_id, vdata);
             }
 
@@ -1003,12 +996,6 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
             | Res::SelfCtor(..)
             | Res::Err => bug!("unexpected resolution: {:?}", res),
         }
-        // Record some extra data for better diagnostics.
-        match res {
-            Res::Def(DefKind::Struct, def_id) => self.insert_field_names_extern(def_id),
-            Res::Def(DefKind::Union, def_id) => self.insert_field_names_extern(def_id),
-            _ => {}
-        }
     }
 
     fn add_macro_use_binding(
@@ -1519,7 +1506,7 @@ impl<'a, 'b, 'tcx> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b, 'tcx> {
         }
 
         // Record field names for error reporting.
-        self.insert_field_names_local(def_id.to_def_id(), &variant.data);
+        self.insert_field_def_ids(def_id, &variant.data);
         self.insert_field_visibilities_local(def_id.to_def_id(), &variant.data);
 
         visit::walk_variant(self, variant);

compiler/rustc_resolve/src/diagnostics.rs

@@ -1581,8 +1581,11 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         )) = binding.kind
         {
             let def_id = self.tcx.parent(ctor_def_id);
-            let fields = self.field_names.get(&def_id)?;
+            return self
-            return fields.iter().map(|name| name.span).reduce(Span::to); // None for `struct Foo()`
+                .field_def_ids(def_id)?
+                .iter()
+                .map(|&field_id| self.def_span(field_id))
+                .reduce(Span::to); // None for `struct Foo()`
         }
         None
     }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1295,19 +1295,23 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         }
                         _ => (": val", "literal", Applicability::HasPlaceholders),
                     };
-                    let (fields, applicability) = match self.r.field_names.get(&def_id) {
+
-                        Some(fields) => (
+                    let field_ids = self.r.field_def_ids(def_id);
-                            fields
+                    let (fields, applicability) = match field_ids {
+                        Some(field_ids) => (
+                            field_ids
                                 .iter()
-                                .map(|f| format!("{}{}", f.node, tail))
+                                .map(|&field_id| {
+                                    format!("{}{tail}", self.r.tcx.item_name(field_id))
+                                })
                                 .collect::<Vec<String>>()
                                 .join(", "),
                             applicability,
                         ),
                         None => ("/* fields */".to_string(), Applicability::HasPlaceholders),
                     };
-                    let pad = match self.r.field_names.get(&def_id) {
+                    let pad = match field_ids {
-                        Some(fields) if fields.is_empty() => "",
+                        Some(field_ids) if field_ids.is_empty() => "",
                         _ => " ",
                     };
                     err.span_suggestion(
@@ -1451,10 +1455,12 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         );
 
                         // Use spans of the tuple struct definition.
-                        self.r
+                        self.r.field_def_ids(def_id).map(|field_ids| {
-                            .field_names
+                            field_ids
-                            .get(&def_id)
+                                .iter()
-                            .map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
+                                .map(|&field_id| self.r.def_span(field_id))
+                                .collect::<Vec<_>>()
+                        })
                     }
                     _ => None,
                 };
@@ -1517,9 +1523,9 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
             (Res::Def(DefKind::Ctor(_, CtorKind::Fn), ctor_def_id), _) if ns == ValueNS => {
                 let def_id = self.r.tcx.parent(ctor_def_id);
                 err.span_label(self.r.def_span(def_id), &format!("`{path_str}` defined here"));
-                let fields = self.r.field_names.get(&def_id).map_or_else(
+                let fields = self.r.field_def_ids(def_id).map_or_else(
                     || "/* fields */".to_string(),
-                    |fields| vec!["_"; fields.len()].join(", "),
+                    |field_ids| vec!["_"; field_ids.len()].join(", "),
                 );
                 err.span_suggestion(
                     span,
@@ -1600,8 +1606,11 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                     if let Some(Res::Def(DefKind::Struct | DefKind::Union, did)) =
                         resolution.full_res()
                     {
-                        if let Some(field_names) = self.r.field_names.get(&did) {
+                        if let Some(field_ids) = self.r.field_def_ids(did) {
-                            if field_names.iter().any(|&field_name| ident.name == field_name.node) {
+                            if field_ids
+                                .iter()
+                                .any(|&field_id| ident.name == self.r.tcx.item_name(field_id))
+                            {
                                 return Some(AssocSuggestion::Field);
                             }
                         }
@@ -2015,11 +2024,12 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
         } else {
             let needs_placeholder = |ctor_def_id: DefId, kind: CtorKind| {
                 let def_id = self.r.tcx.parent(ctor_def_id);
-                let has_no_fields = self.r.field_names.get(&def_id).map_or(false, |f| f.is_empty());
                 match kind {
                     CtorKind::Const => false,
-                    CtorKind::Fn if has_no_fields => false,
+                    CtorKind::Fn => !self
-                    _ => true,
+                        .r
+                        .field_def_ids(def_id)
+                        .map_or(false, |field_ids| field_ids.is_empty()),
                 }
             };
 

compiler/rustc_resolve/src/lib.rs

@@ -50,7 +50,6 @@ use rustc_middle::ty::{ResolverGlobalCtxt, ResolverOutputs};
 use rustc_query_system::ich::StableHashingContext;
 use rustc_session::lint::LintBuffer;
 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind, SyntaxContext, Transparency};
-use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 
@@ -881,10 +880,7 @@ pub struct Resolver<'a, 'tcx> {
 
     /// N.B., this is used only for better diagnostics, not name resolution itself.
     has_self: LocalDefIdSet,
-
+    field_def_ids: LocalDefIdMap<&'tcx [DefId]>,
-    /// Names of fields of an item `DefId` accessible with dot syntax.
-    /// Used for hints during error reporting.
-    field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
 
     /// Span of the privacy modifier in fields of an item `DefId` accessible with dot syntax.
     /// Used for hints during error reporting.
@@ -1249,7 +1245,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             extern_prelude,
 
             has_self: Default::default(),
-            field_names: FxHashMap::default(),
+            field_def_ids: Default::default(),
             field_visibility_spans: FxHashMap::default(),
 
             determined_imports: Vec::new(),
@@ -1877,6 +1873,13 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         }
     }
 
+    fn field_def_ids(&self, def_id: DefId) -> Option<&'tcx [DefId]> {
+        match def_id.as_local() {
+            Some(def_id) => self.field_def_ids.get(&def_id).copied(),
+            None => Some(self.tcx.associated_item_def_ids(def_id)),
+        }
+    }
+
     /// Checks if an expression refers to a function marked with
     /// `#[rustc_legacy_const_generics]` and returns the argument index list
     /// from the attribute.

tests/ui/empty/empty-struct-tuple-pat.stderr

@@ -46,8 +46,8 @@ LL |     XEmpty5(),
    |
 help: use the tuple variant pattern syntax instead
    |
-LL |         XE::XEmpty5(/* fields */) => (),
+LL |         XE::XEmpty5() => (),
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~~~~~~
 help: a unit variant with a similar name exists
    |
 LL |         XE::XEmpty4 => (),

tests/ui/pattern/pat-tuple-field-count-cross.stderr

@@ -113,8 +113,8 @@ LL | pub enum E1 { Z0, Z1(), S(u8, u8, u8) }
    |
 help: use the tuple variant pattern syntax instead
    |
-LL |         E1::Z1(/* fields */) => {}
+LL |         E1::Z1() => {}
-   |         ~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~
 help: a unit variant with a similar name exists
    |
 LL |         E1::Z0 => {}