rustc: Parameterize ty::Visibility over used ID

It allows using `LocalDefId` instead of `DefId` when possible, and also encode cheaper `Visibility<DefIndex>` into metadata.

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -911,8 +911,14 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.root.tables.generics_of.get(self, item_id).unwrap().decode((self, sess))
     }
 
-    fn get_visibility(self, id: DefIndex) -> ty::Visibility {
+    fn get_visibility(self, id: DefIndex) -> ty::Visibility<DefId> {
-        self.root.tables.visibility.get(self, id).unwrap().decode(self)
+        self.root
+            .tables
+            .visibility
+            .get(self, id)
+            .unwrap()
+            .decode(self)
+            .map_id(|index| self.local_def_id(index))
     }
 
     fn get_trait_item_def_id(self, id: DefIndex) -> Option<DefId> {
@@ -1182,7 +1188,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(move |index| respan(self.get_span(index, sess), self.item_name(index)))
     }
 
-    fn get_struct_field_visibilities(self, id: DefIndex) -> impl Iterator<Item = Visibility> + 'a {
+    fn get_struct_field_visibilities(
+        self,
+        id: DefIndex,
+    ) -> impl Iterator<Item = Visibility<DefId>> + 'a {
         self.root
             .tables
             .children

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

@@ -210,7 +210,6 @@ provide! { tcx, def_id, other, cdata,
     lookup_const_stability => { table }
     lookup_default_body_stability => { table }
     lookup_deprecation_entry => { table }
-    visibility => { table }
     unused_generic_params => { table }
     opt_def_kind => { table_direct }
     impl_parent => { table }
@@ -225,6 +224,7 @@ provide! { tcx, def_id, other, cdata,
     generator_kind => { table }
     trait_def => { table }
 
+    visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }
     adt_destructor => {
         let _ = cdata;
@@ -485,7 +485,7 @@ impl CStore {
     pub fn struct_field_visibilities_untracked(
         &self,
         def: DefId,
-    ) -> impl Iterator<Item = Visibility> + '_ {
+    ) -> impl Iterator<Item = Visibility<DefId>> + '_ {
         self.get_crate_data(def.krate).get_struct_field_visibilities(def.index)
     }
 
@@ -493,7 +493,7 @@ impl CStore {
         self.get_crate_data(def.krate).get_ctor_def_id_and_kind(def.index)
     }
 
-    pub fn visibility_untracked(&self, def: DefId) -> Visibility {
+    pub fn visibility_untracked(&self, def: DefId) -> Visibility<DefId> {
         self.get_crate_data(def.krate).get_visibility(def.index)
     }
 

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1138,7 +1138,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.codegen_fn_attrs[def_id] <- self.tcx.codegen_fn_attrs(def_id));
             }
             if should_encode_visibility(def_kind) {
-                record!(self.tables.visibility[def_id] <- self.tcx.visibility(def_id));
+                let vis =
+                    self.tcx.local_visibility(local_id).map_id(|def_id| def_id.local_def_index);
+                record!(self.tables.visibility[def_id] <- vis);
             }
             if should_encode_stability(def_kind) {
                 self.encode_stability(def_id);
@@ -1727,7 +1729,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             self.tables.opt_def_kind.set(LOCAL_CRATE.as_def_id().index, DefKind::Mod);
             record!(self.tables.def_span[LOCAL_CRATE.as_def_id()] <- tcx.def_span(LOCAL_CRATE.as_def_id()));
             self.encode_attrs(LOCAL_CRATE.as_def_id().expect_local());
-            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- tcx.visibility(LOCAL_CRATE.as_def_id()));
+            let vis = tcx.local_visibility(CRATE_DEF_ID).map_id(|def_id| def_id.local_def_index);
+            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- vis);
             if let Some(stability) = stability {
                 record!(self.tables.lookup_stability[LOCAL_CRATE.as_def_id()] <- stability);
             }

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -338,7 +338,7 @@ define_tables! {
     children: Table<DefIndex, LazyArray<DefIndex>>,
 
     opt_def_kind: Table<DefIndex, DefKind>,
-    visibility: Table<DefIndex, LazyValue<ty::Visibility>>,
+    visibility: Table<DefIndex, LazyValue<ty::Visibility<DefIndex>>>,
     def_span: Table<DefIndex, LazyValue<Span>>,
     def_ident_span: Table<DefIndex, LazyValue<Span>>,
     lookup_stability: Table<DefIndex, LazyValue<attr::Stability>>,

compiler/rustc_middle/src/metadata.rs

@@ -2,6 +2,7 @@ use crate::ty;
 
 use rustc_hir::def::Res;
 use rustc_macros::HashStable;
+use rustc_span::def_id::DefId;
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
@@ -18,7 +19,7 @@ pub struct ModChild {
     /// Local variables cannot be exported, so this `Res` doesn't need the ID parameter.
     pub res: Res<!>,
     /// Visibility of the item.
-    pub vis: ty::Visibility,
+    pub vis: ty::Visibility<DefId>,
     /// Span of the item.
     pub span: Span,
     /// A proper `macro_rules` item (not a reexport).

compiler/rustc_middle/src/query/mod.rs

@@ -1607,7 +1607,7 @@ rustc_queries! {
         desc { "looking up late bound vars" }
     }
 
-    query visibility(def_id: DefId) -> ty::Visibility {
+    query visibility(def_id: DefId) -> ty::Visibility<DefId> {
         desc { |tcx| "computing visibility of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
     }

compiler/rustc_middle/src/ty/assoc.rs

@@ -42,7 +42,7 @@ impl AssocItem {
     }
 
     #[inline]
-    pub fn visibility(&self, tcx: TyCtxt<'_>) -> Visibility {
+    pub fn visibility(&self, tcx: TyCtxt<'_>) -> Visibility<DefId> {
         tcx.visibility(self.def_id)
     }
 

compiler/rustc_middle/src/ty/context.rs

@@ -22,6 +22,7 @@ use crate::ty::{
     FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy, IntTy, IntVar, IntVid, List,
     ParamConst, ParamTy, PolyFnSig, Predicate, PredicateKind, PredicateS, ProjectionTy, Region,
     RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar, TyVid, TypeAndMut, UintTy,
+    Visibility,
 };
 use rustc_ast as ast;
 use rustc_data_structures::fingerprint::Fingerprint;
@@ -1728,6 +1729,11 @@ impl<'tcx> TyCtxt<'tcx> {
             .chain(self.crates(()).iter().copied())
             .flat_map(move |cnum| self.traits_in_crate(cnum).iter().copied())
     }
+
+    #[inline]
+    pub fn local_visibility(self, def_id: LocalDefId) -> Visibility {
+        self.visibility(def_id.to_def_id()).expect_local()
+    }
 }
 
 /// A trait implemented for all `X<'a>` types that can be safely and

compiler/rustc_middle/src/ty/mod.rs

@@ -259,11 +259,11 @@ impl fmt::Display for ImplPolarity {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Copy, Hash, Encodable, Decodable, HashStable)]
-pub enum Visibility {
+pub enum Visibility<Id = LocalDefId> {
     /// Visible everywhere (including in other crates).
     Public,
     /// Visible only in the given crate-local module.
-    Restricted(DefId),
+    Restricted(Id),
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable)]
@@ -354,28 +354,45 @@ impl<'tcx> DefIdTree for TyCtxt<'tcx> {
     }
 }
 
-impl Visibility {
+impl<Id> Visibility<Id> {
-    /// Returns `true` if an item with this visibility is accessible from the given block.
+    pub fn is_public(self) -> bool {
-    pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
+        matches!(self, Visibility::Public)
-        let restriction = match self {
+    }
-            // Public items are visible everywhere.
-            Visibility::Public => return true,
-            // Restricted items are visible in an arbitrary local module.
-            Visibility::Restricted(other) if other.krate != module.krate => return false,
-            Visibility::Restricted(module) => module,
-        };
 
-        tree.is_descendant_of(module, restriction)
+    pub fn map_id<OutId>(self, f: impl FnOnce(Id) -> OutId) -> Visibility<OutId> {
+        match self {
+            Visibility::Public => Visibility::Public,
+            Visibility::Restricted(id) => Visibility::Restricted(f(id)),
+        }
+    }
+}
+
+impl<Id: Into<DefId>> Visibility<Id> {
+    pub fn to_def_id(self) -> Visibility<DefId> {
+        self.map_id(Into::into)
+    }
+
+    /// Returns `true` if an item with this visibility is accessible from the given module.
+    pub fn is_accessible_from(self, module: impl Into<DefId>, tree: impl DefIdTree) -> bool {
+        match self {
+            // Public items are visible everywhere.
+            Visibility::Public => true,
+            Visibility::Restricted(id) => tree.is_descendant_of(module.into(), id.into()),
+        }
     }
 
     /// Returns `true` if this visibility is at least as accessible as the given visibility
-    pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
+    pub fn is_at_least(self, vis: Visibility<impl Into<DefId>>, tree: impl DefIdTree) -> bool {
-        let vis_restriction = match vis {
+        match vis {
-            Visibility::Public => return self == Visibility::Public,
+            Visibility::Public => self.is_public(),
-            Visibility::Restricted(module) => module,
+            Visibility::Restricted(id) => self.is_accessible_from(id, tree),
-        };
+        }
+    }
+}
 
-        self.is_accessible_from(vis_restriction, tree)
+impl Visibility<DefId> {
+    pub fn expect_local(self) -> Visibility {
+        self.map_id(|id| id.expect_local())
     }
 
     // Returns `true` if this item is visible anywhere in the local crate.
@@ -385,10 +402,6 @@ impl Visibility {
             Visibility::Restricted(def_id) => def_id.is_local(),
         }
     }
-
-    pub fn is_public(self) -> bool {
-        matches!(self, Visibility::Public)
-    }
 }
 
 /// The crate variances map is computed during typeck and contains the
@@ -1790,7 +1803,7 @@ pub enum VariantDiscr {
 pub struct FieldDef {
     pub did: DefId,
     pub name: Symbol,
-    pub vis: Visibility,
+    pub vis: Visibility<DefId>,
 }
 
 impl PartialEq for FieldDef {

compiler/rustc_middle/src/ty/parameterized.rs

@@ -1,4 +1,4 @@
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, DefIndex};
 use rustc_index::vec::{Idx, IndexVec};
 
 use crate::middle::exported_symbols::ExportedSymbol;
@@ -60,7 +60,7 @@ trivially_parameterized_over_tcx! {
     ty::ImplPolarity,
     ty::ReprOptions,
     ty::TraitDef,
-    ty::Visibility,
+    ty::Visibility<DefIndex>,
     ty::adjustment::CoerceUnsizedInfo,
     ty::fast_reject::SimplifiedTypeGen<DefId>,
     rustc_ast::Attribute,

compiler/rustc_privacy/src/lib.rs

@@ -1,6 +1,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(associated_type_defaults)]
 #![feature(control_flow_enum)]
+#![feature(let_else)]
 #![feature(rustc_private)]
 #![feature(try_blocks)]
 #![recursion_limit = "256"]
@@ -334,7 +335,9 @@ impl<'a, 'tcx, VL: VisibilityLike> DefIdVisitor<'tcx> for FindMin<'a, 'tcx, VL>
         _kind: &str,
         _descr: &dyn fmt::Display,
     ) -> ControlFlow<Self::BreakTy> {
-        self.min = VL::new_min(self, def_id);
+        if let Some(def_id) = def_id.as_local() {
+            self.min = VL::new_min(self, def_id);
+        }
         ControlFlow::CONTINUE
     }
 }
@@ -342,7 +345,7 @@ impl<'a, 'tcx, VL: VisibilityLike> DefIdVisitor<'tcx> for FindMin<'a, 'tcx, VL>
 trait VisibilityLike: Sized {
     const MAX: Self;
     const SHALLOW: bool = false;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self;
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self;
 
     // Returns an over-approximation (`skip_assoc_tys` = true) of visibility due to
     // associated types for which we can't determine visibility precisely.
@@ -357,8 +360,8 @@ trait VisibilityLike: Sized {
 }
 impl VisibilityLike for ty::Visibility {
     const MAX: Self = ty::Visibility::Public;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self {
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self {
-        min(find.tcx.visibility(def_id), find.min, find.tcx)
+        min(find.tcx.local_visibility(def_id), find.min, find.tcx)
     }
 }
 impl VisibilityLike for Option<AccessLevel> {
@@ -373,15 +376,8 @@ impl VisibilityLike for Option<AccessLevel> {
     // both "shallow" version of its self type and "shallow" version of its trait if it exists
     // (which require reaching the `DefId`s in them).
     const SHALLOW: bool = true;
-    fn new_min(find: &FindMin<'_, '_, Self>, def_id: DefId) -> Self {
+    fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self {
-        cmp::min(
+        cmp::min(find.access_levels.map.get(&def_id).copied(), find.min)
-            if let Some(def_id) = def_id.as_local() {
-                find.access_levels.map.get(&def_id).copied()
-            } else {
-                Self::MAX
-            },
-            find.min,
-        )
     }
 }
 
@@ -511,15 +507,15 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         let module = self.tcx.hir().get_module(module_def_id).0;
         for item_id in module.item_ids {
             let def_kind = self.tcx.def_kind(item_id.def_id);
-            let vis = self.tcx.visibility(item_id.def_id);
+            let vis = self.tcx.local_visibility(item_id.def_id);
             self.update_macro_reachable_def(item_id.def_id, def_kind, vis, defining_mod);
         }
         if let Some(exports) = self.tcx.module_reexports(module_def_id) {
             for export in exports {
-                if export.vis.is_accessible_from(defining_mod.to_def_id(), self.tcx) {
+                if export.vis.is_accessible_from(defining_mod, self.tcx) {
                     if let Res::Def(def_kind, def_id) = export.res {
                         if let Some(def_id) = def_id.as_local() {
-                            let vis = self.tcx.visibility(def_id.to_def_id());
+                            let vis = self.tcx.local_visibility(def_id);
                             self.update_macro_reachable_def(def_id, def_kind, vis, defining_mod);
                         }
                     }
@@ -542,7 +538,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         match def_kind {
             // No type privacy, so can be directly marked as reachable.
             DefKind::Const | DefKind::Static(_) | DefKind::TraitAlias | DefKind::TyAlias => {
-                if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                if vis.is_accessible_from(module, self.tcx) {
                     self.update(def_id, level);
                 }
             }
@@ -554,7 +550,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             DefKind::Macro(_) => {
                 let item = self.tcx.hir().expect_item(def_id);
                 if let hir::ItemKind::Macro(MacroDef { macro_rules: false, .. }, _) = item.kind {
-                    if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                    if vis.is_accessible_from(module, self.tcx) {
                         self.update(def_id, level);
                     }
                 }
@@ -565,7 +561,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             // hygiene these don't need to be marked reachable. The contents of
             // the module, however may be reachable.
             DefKind::Mod => {
-                if vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                if vis.is_accessible_from(module, self.tcx) {
                     self.update_macro_reachable(def_id, module);
                 }
             }
@@ -579,8 +575,8 @@ impl<'tcx> EmbargoVisitor<'tcx> {
                     {
                         for field in struct_def.fields() {
                             let def_id = self.tcx.hir().local_def_id(field.hir_id);
-                            let field_vis = self.tcx.visibility(def_id);
+                            let field_vis = self.tcx.local_visibility(def_id);
-                            if field_vis.is_accessible_from(module.to_def_id(), self.tcx) {
+                            if field_vis.is_accessible_from(module, self.tcx) {
                                 self.reach(def_id, level).ty();
                             }
                         }
@@ -654,7 +650,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             hir::ItemKind::Impl(ref impl_) => {
                 for impl_item_ref in impl_.items {
                     if impl_.of_trait.is_some()
-                        || self.tcx.visibility(impl_item_ref.id.def_id) == ty::Visibility::Public
+                        || self.tcx.visibility(impl_item_ref.id.def_id).is_public()
                     {
                         self.update(impl_item_ref.id.def_id, item_level);
                     }
@@ -682,7 +678,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
             }
             hir::ItemKind::ForeignMod { items, .. } => {
                 for foreign_item in items {
-                    if self.tcx.visibility(foreign_item.id.def_id) == ty::Visibility::Public {
+                    if self.tcx.visibility(foreign_item.id.def_id).is_public() {
                         self.update(foreign_item.id.def_id, item_level);
                     }
                 }
@@ -1117,7 +1113,7 @@ impl<'tcx> TypePrivacyVisitor<'tcx> {
     }
 
     fn item_is_accessible(&self, did: DefId) -> bool {
-        self.tcx.visibility(did).is_accessible_from(self.current_item.to_def_id(), self.tcx)
+        self.tcx.visibility(did).is_accessible_from(self.current_item, self.tcx)
     }
 
     // Take node-id of an expression or pattern and check its type for privacy.
@@ -1609,8 +1605,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
                     let mut found_pub_static = false;
                     for impl_item_ref in impl_.items {
                         if self.access_levels.is_reachable(impl_item_ref.id.def_id)
-                            || self.tcx.visibility(impl_item_ref.id.def_id)
+                            || self.tcx.visibility(impl_item_ref.id.def_id).is_public()
-                                == ty::Visibility::Public
                         {
                             let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
                             match impl_item_ref.kind {
@@ -1780,17 +1775,17 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
             );
         }
 
-        let hir_id = match def_id.as_local() {
+        let Some(local_def_id) = def_id.as_local() else {
-            Some(def_id) => self.tcx.hir().local_def_id_to_hir_id(def_id),
+            return false;
-            None => return false,
         };
 
-        let vis = self.tcx.visibility(def_id);
+        let vis = self.tcx.local_visibility(local_def_id);
         if !vis.is_at_least(self.required_visibility, self.tcx) {
+            let hir_id = self.tcx.hir().local_def_id_to_hir_id(local_def_id);
             let vis_descr = match vis {
                 ty::Visibility::Public => "public",
                 ty::Visibility::Restricted(vis_def_id) => {
-                    if vis_def_id == self.tcx.parent_module(hir_id).to_def_id() {
+                    if vis_def_id == self.tcx.parent_module(hir_id) {
                         "private"
                     } else if vis_def_id.is_top_level_module() {
                         "crate-private"
@@ -1906,7 +1901,7 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
 
     pub fn check_item(&mut self, id: ItemId) {
         let tcx = self.tcx;
-        let item_visibility = tcx.visibility(id.def_id);
+        let item_visibility = tcx.local_visibility(id.def_id);
         let def_kind = tcx.def_kind(id.def_id);
 
         match def_kind {
@@ -1957,7 +1952,7 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
                 let item = tcx.hir().item(id);
                 if let hir::ItemKind::ForeignMod { items, .. } = item.kind {
                     for foreign_item in items {
-                        let vis = tcx.visibility(foreign_item.id.def_id);
+                        let vis = tcx.local_visibility(foreign_item.id.def_id);
                         self.check(foreign_item.id.def_id, vis).generics().predicates().ty();
                     }
                 }
@@ -1972,7 +1967,7 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
 
                     for field in struct_def.fields() {
                         let def_id = tcx.hir().local_def_id(field.hir_id);
-                        let field_visibility = tcx.visibility(def_id);
+                        let field_visibility = tcx.local_visibility(def_id);
                         self.check(def_id, min(item_visibility, field_visibility, tcx)).ty();
                     }
                 }
@@ -1992,7 +1987,7 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'tcx> {
                     }
                     for impl_item_ref in impl_.items {
                         let impl_item_vis = if impl_.of_trait.is_none() {
-                            min(tcx.visibility(impl_item_ref.id.def_id), impl_vis, tcx)
+                            min(tcx.local_visibility(impl_item_ref.id.def_id), impl_vis, tcx)
                         } else {
                             impl_vis
                         };
@@ -2019,8 +2014,11 @@ pub fn provide(providers: &mut Providers) {
     };
 }
 
-fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
+fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility<DefId> {
-    let def_id = def_id.expect_local();
+    local_visibility(tcx, def_id.expect_local()).to_def_id()
+}
+
+fn local_visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility {
     match tcx.resolutions(()).visibilities.get(&def_id) {
         Some(vis) => *vis,
         None => {
@@ -2037,7 +2035,7 @@ fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
                 | Node::Item(hir::Item {
                     kind: hir::ItemKind::Use(_, hir::UseKind::ListStem) | hir::ItemKind::OpaqueTy(..),
                     ..
-                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id).to_def_id()),
+                }) => ty::Visibility::Restricted(tcx.parent_module(hir_id)),
                 // Visibilities of trait impl items are inherited from their traits
                 // and are not filled in resolve.
                 Node::ImplItem(impl_item) => {
@@ -2050,7 +2048,7 @@ fn visibility(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Visibility {
                                 tcx.sess.delay_span_bug(tr.path.span, "trait without a def-id");
                                 ty::Visibility::Public
                             },
-                            |def_id| tcx.visibility(def_id),
+                            |def_id| tcx.visibility(def_id).expect_local(),
                         ),
                         _ => span_bug!(impl_item.span, "the parent is not a trait impl"),
                     }

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -39,24 +39,26 @@ use std::ptr;
 
 type Res = def::Res<NodeId>;
 
-impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, LocalExpnId) {
+impl<'a, Id: Into<DefId>> ToNameBinding<'a>
+    for (Module<'a>, ty::Visibility<Id>, Span, LocalExpnId)
+{
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Module(self.0),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
     }
 }
 
-impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId) {
+impl<'a, Id: Into<DefId>> ToNameBinding<'a> for (Res, ty::Visibility<Id>, Span, LocalExpnId) {
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Res(self.0, false),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
@@ -70,7 +72,7 @@ impl<'a> ToNameBinding<'a> for (Res, ty::Visibility, Span, LocalExpnId, IsMacroE
         arenas.alloc_name_binding(NameBinding {
             kind: NameBindingKind::Res(self.0, true),
             ambiguity: None,
-            vis: self.1,
+            vis: self.1.to_def_id(),
             span: self.2,
             expansion: self.3,
         })
@@ -260,7 +262,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         self.r.visibilities[&def_id.expect_local()]
                     }
                     // Otherwise, the visibility is restricted to the nearest parent `mod` item.
-                    _ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
+                    _ => ty::Visibility::Restricted(
+                        self.parent_scope.module.nearest_parent_mod().expect_local(),
+                    ),
                 })
             }
             ast::VisibilityKind::Restricted { ref path, id, .. } => {
@@ -311,7 +315,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                             } else {
                                 let vis = ty::Visibility::Restricted(res.def_id());
                                 if self.r.is_accessible_from(vis, parent_scope.module) {
-                                    Ok(vis)
+                                    Ok(vis.expect_local())
                                 } else {
                                     Err(VisResolutionError::AncestorOnly(path.span))
                                 }
@@ -649,7 +653,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         true,
                         // The whole `use` item
                         item,
-                        ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
+                        ty::Visibility::Restricted(
+                            self.parent_scope.module.nearest_parent_mod().expect_local(),
+                        ),
                         root_span,
                     );
                 }
@@ -765,10 +771,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 if let Some(ctor_node_id) = vdata.ctor_id() {
                     // If the structure is marked as non_exhaustive then lower the visibility
                     // to within the crate.
-                    let mut ctor_vis = if vis == ty::Visibility::Public
+                    let mut ctor_vis = if vis.is_public()
                         && self.r.session.contains_name(&item.attrs, sym::non_exhaustive)
                     {
-                        ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+                        ty::Visibility::Restricted(CRATE_DEF_ID)
                     } else {
                         vis
                     };
@@ -785,7 +791,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         if ctor_vis.is_at_least(field_vis, &*self.r) {
                             ctor_vis = field_vis;
                         }
-                        ret_fields.push(field_vis);
+                        ret_fields.push(field_vis.to_def_id());
                     }
                     let ctor_def_id = self.r.local_def_id(ctor_node_id);
                     let ctor_res = Res::Def(
@@ -795,7 +801,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
                     self.r.visibilities.insert(ctor_def_id, ctor_vis);
 
-                    self.r.struct_constructors.insert(def_id, (ctor_res, ctor_vis, ret_fields));
+                    self.r
+                        .struct_constructors
+                        .insert(def_id, (ctor_res, ctor_vis.to_def_id(), ret_fields));
                 }
             }
 
@@ -867,8 +875,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         }
         .map(|module| {
             let used = self.process_macro_use_imports(item, module);
-            let binding =
+            let vis = ty::Visibility::<LocalDefId>::Public;
-                (module, ty::Visibility::Public, sp, expansion).to_name_binding(self.r.arenas);
+            let binding = (module, vis, sp, expansion).to_name_binding(self.r.arenas);
             (used, Some(ModuleOrUniformRoot::Module(module)), binding)
         })
         .unwrap_or((true, None, self.r.dummy_binding));
@@ -1117,7 +1125,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 root_span: span,
                 span,
                 module_path: Vec::new(),
-                vis: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id()))),
+                vis: Cell::new(Some(ty::Visibility::Restricted(CRATE_DEF_ID))),
                 used: Cell::new(false),
             })
         };
@@ -1263,7 +1271,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             let vis = if is_macro_export {
                 ty::Visibility::Public
             } else {
-                ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+                ty::Visibility::Restricted(CRATE_DEF_ID)
             };
             let binding = (res, vis, span, expansion).to_name_binding(self.r.arenas);
             self.r.set_binding_parent_module(binding, parent_scope.module);
@@ -1294,7 +1302,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 }
                 _ => self.resolve_visibility(&item.vis),
             };
-            if vis != ty::Visibility::Public {
+            if !vis.is_public() {
                 self.insert_unused_macro(ident, def_id, item.id, &rule_spans);
             }
             self.r.define(module, ident, MacroNS, (res, vis, span, expansion));
@@ -1507,10 +1515,10 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
         self.r.visibilities.insert(def_id, vis);
 
         // If the variant is marked as non_exhaustive then lower the visibility to within the crate.
-        let ctor_vis = if vis == ty::Visibility::Public
+        let ctor_vis = if vis.is_public()
             && self.r.session.contains_name(&variant.attrs, sym::non_exhaustive)
         {
-            ty::Visibility::Restricted(CRATE_DEF_ID.to_def_id())
+            ty::Visibility::Restricted(CRATE_DEF_ID)
         } else {
             vis
         };

compiler/rustc_resolve/src/ident.rs

@@ -6,6 +6,7 @@ use rustc_middle::bug;
 use rustc_middle::ty;
 use rustc_session::lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK;
 use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext};
 use rustc_span::symbol::{kw, Ident};
@@ -26,6 +27,8 @@ use Determinacy::*;
 use Namespace::*;
 use RibKind::*;
 
+type Visibility = ty::Visibility<LocalDefId>;
+
 impl<'a> Resolver<'a> {
     /// A generic scope visitor.
     /// Visits scopes in order to resolve some identifier in them or perform other actions.
@@ -424,8 +427,7 @@ impl<'a> Resolver<'a> {
                 let ident = Ident::new(orig_ident.name, orig_ident.span.with_ctxt(ctxt));
                 let ok = |res, span, arenas| {
                     Ok((
-                        (res, ty::Visibility::Public, span, LocalExpnId::ROOT)
+                        (res, Visibility::Public, span, LocalExpnId::ROOT).to_name_binding(arenas),
-                            .to_name_binding(arenas),
                         Flags::empty(),
                     ))
                 };
@@ -438,7 +440,7 @@ impl<'a> Resolver<'a> {
                         {
                             let binding = (
                                 Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper),
-                                ty::Visibility::Public,
+                                Visibility::Public,
                                 attr.span,
                                 expn_id,
                             )
@@ -841,9 +843,8 @@ impl<'a> Resolver<'a> {
                 if ns == TypeNS {
                     if ident.name == kw::Crate || ident.name == kw::DollarCrate {
                         let module = self.resolve_crate_root(ident);
-                        let binding =
+                        let binding = (module, Visibility::Public, module.span, LocalExpnId::ROOT)
-                            (module, ty::Visibility::Public, module.span, LocalExpnId::ROOT)
+                            .to_name_binding(self.arenas);
-                                .to_name_binding(self.arenas);
                         return Ok(binding);
                     } else if ident.name == kw::Super || ident.name == kw::SelfLower {
                         // FIXME: Implement these with renaming requirements so that e.g.

compiler/rustc_resolve/src/imports.rs

@@ -214,7 +214,7 @@ impl<'a> Resolver<'a> {
         binding: &'a NameBinding<'a>,
         import: &'a Import<'a>,
     ) -> &'a NameBinding<'a> {
-        let import_vis = import.expect_vis();
+        let import_vis = import.expect_vis().to_def_id();
         let vis = if binding.vis.is_at_least(import_vis, self)
             || pub_use_of_private_extern_crate_hack(import, binding)
         {
@@ -227,7 +227,7 @@ impl<'a> Resolver<'a> {
             if vis == import_vis
                 || max_vis.get().map_or(true, |max_vis| vis.is_at_least(max_vis, self))
             {
-                max_vis.set(Some(vis))
+                max_vis.set(Some(vis.expect_local()))
             }
         }
 

compiler/rustc_resolve/src/lib.rs

@@ -648,7 +648,7 @@ pub struct NameBinding<'a> {
     ambiguity: Option<(&'a NameBinding<'a>, AmbiguityKind)>,
     expansion: LocalExpnId,
     span: Span,
-    vis: ty::Visibility,
+    vis: ty::Visibility<DefId>,
 }
 
 pub trait ToNameBinding<'a> {
@@ -1012,7 +1012,7 @@ pub struct Resolver<'a> {
     /// Table for mapping struct IDs into struct constructor IDs,
     /// it's not used during normal resolution, only for better error reporting.
     /// Also includes of list of each fields visibility
-    struct_constructors: DefIdMap<(Res, ty::Visibility, Vec<ty::Visibility>)>,
+    struct_constructors: DefIdMap<(Res, ty::Visibility<DefId>, Vec<ty::Visibility<DefId>>)>,
 
     /// Features enabled for this crate.
     active_features: FxHashSet<Symbol>,
@@ -1808,7 +1808,11 @@ impl<'a> Resolver<'a> {
         self.pat_span_map.insert(node, span);
     }
 
-    fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
+    fn is_accessible_from(
+        &self,
+        vis: ty::Visibility<impl Into<DefId>>,
+        module: Module<'a>,
+    ) -> bool {
         vis.is_accessible_from(module.nearest_parent_mod(), self)
     }
 
@@ -1862,10 +1866,8 @@ impl<'a> Resolver<'a> {
                     self.crate_loader.maybe_process_path_extern(ident.name)?
                 };
                 let crate_root = self.expect_module(crate_id.as_def_id());
-                Some(
+                let vis = ty::Visibility::<LocalDefId>::Public;
-                    (crate_root, ty::Visibility::Public, DUMMY_SP, LocalExpnId::ROOT)
+                Some((crate_root, vis, DUMMY_SP, LocalExpnId::ROOT).to_name_binding(self.arenas))
-                        .to_name_binding(self.arenas),
-                )
             }
         })
     }

compiler/rustc_span/src/def_id.rs

@@ -305,6 +305,12 @@ impl DefId {
     }
 }
 
+impl From<LocalDefId> for DefId {
+    fn from(local: LocalDefId) -> DefId {
+        local.to_def_id()
+    }
+}
+
 impl<E: Encoder> Encodable<E> for DefId {
     default fn encode(&self, s: &mut E) {
         self.krate.encode(s);

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1895,9 +1895,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                         // FIXME(compiler-errors): This could be generalized, both to
                         // be more granular, and probably look past other `#[fundamental]`
                         // types, too.
-                        self.tcx
+                        self.tcx.visibility(def.did()).is_accessible_from(body_id.owner, self.tcx)
-                            .visibility(def.did())
-                            .is_accessible_from(body_id.owner.to_def_id(), self.tcx)
                     } else {
                         true
                     }

compiler/rustc_typeck/src/check/demand.rs

@@ -375,7 +375,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                     let field_is_local = sole_field.did.is_local();
                     let field_is_accessible =
-                        sole_field.vis.is_accessible_from(expr.hir_id.owner.to_def_id(), self.tcx)
+                        sole_field.vis.is_accessible_from(expr.hir_id.owner, self.tcx)
                         // Skip suggestions for unstable public fields (for example `Pin::pointer`)
                         && matches!(self.tcx.eval_stability(sole_field.did, None, expr.span, None), EvalResult::Allow | EvalResult::Unmarked);
 

compiler/rustc_typeck/src/check/expr.rs

@@ -1729,9 +1729,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let private_fields: Vec<&ty::FieldDef> = variant
                 .fields
                 .iter()
-                .filter(|field| {
+                .filter(|field| !field.vis.is_accessible_from(tcx.parent_module(expr_id), tcx))
-                    !field.vis.is_accessible_from(tcx.parent_module(expr_id).to_def_id(), tcx)
-                })
                 .collect();
 
             if !private_fields.is_empty() {
@@ -2343,7 +2341,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if let ty::Adt(def, _) = output_ty.kind() && !def.is_enum() {
                 def.non_enum_variant().fields.iter().any(|field| {
                     field.ident(self.tcx) == ident
-                        && field.vis.is_accessible_from(expr.hir_id.owner.to_def_id(), self.tcx)
+                        && field.vis.is_accessible_from(expr.hir_id.owner, self.tcx)
                 })
             } else if let ty::Tuple(tys) = output_ty.kind()
                 && let Ok(idx) = ident.as_str().parse::<usize>()

compiler/rustc_typeck/src/check/method/suggest.rs

@@ -1161,7 +1161,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => None,
         });
         if let Some((field, field_ty)) = field_receiver {
-            let scope = tcx.parent_module(self.body_id).to_def_id();
+            let scope = tcx.parent_module(self.body_id);
             let is_accessible = field.vis.is_accessible_from(scope, tcx);
 
             if is_accessible {

compiler/rustc_typeck/src/check/pat.rs

@@ -1397,7 +1397,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .iter()
                 .copied()
                 .filter(|(field, _)| {
-                    field.vis.is_accessible_from(tcx.parent_module(pat.hir_id).to_def_id(), tcx)
+                    field.vis.is_accessible_from(tcx.parent_module(pat.hir_id), tcx)
                         && !matches!(
                             tcx.eval_stability(field.did, None, DUMMY_SP, None),
                             EvalResult::Deny { .. }

src/librustdoc/clean/mod.rs

@@ -1777,7 +1777,7 @@ fn is_field_vis_inherited(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     }
 }
 
-pub(crate) fn clean_visibility(vis: ty::Visibility) -> Visibility {
+pub(crate) fn clean_visibility(vis: ty::Visibility<DefId>) -> Visibility {
     match vis {
         ty::Visibility::Public => Visibility::Public,
         ty::Visibility::Restricted(module) => Visibility::Restricted(module),
@@ -2111,8 +2111,8 @@ fn clean_use_statement<'tcx>(
     // `pub(super)` or higher. If the current module is the top level
     // module, there isn't really a parent module, which makes the results
     // meaningless. In this case, we make sure the answer is `false`.
-    let is_visible_from_parent_mod = visibility.is_accessible_from(parent_mod.to_def_id(), cx.tcx)
+    let is_visible_from_parent_mod =
-        && !current_mod.is_top_level_module();
+        visibility.is_accessible_from(parent_mod, cx.tcx) && !current_mod.is_top_level_module();
 
     if pub_underscore {
         if let Some(ref inline) = inline_attr {

src/tools/clippy/clippy_lints/src/default.rs

@@ -142,7 +142,7 @@ impl<'tcx> LateLintPass<'tcx> for Default {
                 if adt.is_struct();
                 let variant = adt.non_enum_variant();
                 if adt.did().is_local() || !variant.is_field_list_non_exhaustive();
-                let module_did = cx.tcx.parent_module(stmt.hir_id).to_def_id();
+                let module_did = cx.tcx.parent_module(stmt.hir_id);
                 if variant
                     .fields
                     .iter()

src/tools/clippy/clippy_lints/src/derive.rs

@@ -15,7 +15,7 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::{
     self, Binder, BoundConstness, GenericParamDefKind, ImplPolarity, ParamEnv, PredicateKind, TraitPredicate, TraitRef,
-    Ty, TyCtxt, Visibility,
+    Ty, TyCtxt,
 };
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
@@ -464,7 +464,7 @@ impl<'tcx> Visitor<'tcx> for UnsafeVisitor<'_, 'tcx> {
 fn check_partial_eq_without_eq<'tcx>(cx: &LateContext<'tcx>, span: Span, trait_ref: &hir::TraitRef<'_>, ty: Ty<'tcx>) {
     if_chain! {
         if let ty::Adt(adt, substs) = ty.kind();
-        if cx.tcx.visibility(adt.did()) == Visibility::Public;
+        if cx.tcx.visibility(adt.did()).is_public();
         if let Some(eq_trait_def_id) = cx.tcx.get_diagnostic_item(sym::Eq);
         if let Some(def_id) = trait_ref.trait_def_id();
         if cx.tcx.is_diagnostic_item(sym::PartialEq, def_id);