rustc_middle: Rename Export to ModChild and add some comments

Also rename `module_exports`/`export_map` to `module_reexports`/`reexport_map` for clarity.

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -21,7 +21,7 @@ use rustc_hir::definitions::{DefKey, DefPath, DefPathData, DefPathHash};
 use rustc_hir::diagnostic_items::DiagnosticItems;
 use rustc_hir::lang_items;
 use rustc_index::vec::{Idx, IndexVec};
-use rustc_middle::hir::exports::Export;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc_middle::mir::{self, Body, Promoted};
@@ -1082,7 +1082,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     fn for_each_module_child(
         &self,
         id: DefIndex,
-        mut callback: impl FnMut(Export),
+        mut callback: impl FnMut(ModChild),
         sess: &Session,
     ) {
         if let Some(data) = &self.root.proc_macro_data {
@@ -1096,7 +1096,12 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                         self.local_def_id(def_index),
                     );
                     let ident = self.item_ident(def_index, sess);
-                    callback(Export { ident, res, vis: ty::Visibility::Public, span: ident.span });
+                    callback(ModChild {
+                        ident,
+                        res,
+                        vis: ty::Visibility::Public,
+                        span: ident.span,
+                    });
                 }
             }
             return;
@@ -1117,7 +1122,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                     let vis = self.get_visibility(child_index);
                     let span = self.get_span(child_index, sess);
 
-                    callback(Export { ident, res, vis, span });
+                    callback(ModChild { ident, res, vis, span });
 
                     // For non-re-export structs and variants add their constructors to children.
                     // Re-export lists automatically contain constructors when necessary.
@@ -1129,7 +1134,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                                 let ctor_res =
                                     Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
                                 let vis = self.get_visibility(ctor_def_id.index);
-                                callback(Export { res: ctor_res, vis, ident, span });
+                                callback(ModChild { ident, res: ctor_res, vis, span });
                             }
                         }
                         DefKind::Variant => {
@@ -1154,7 +1159,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                                     vis = ty::Visibility::Restricted(crate_def_id);
                                 }
                             }
-                            callback(Export { res: ctor_res, ident, vis, span });
+                            callback(ModChild { ident, res: ctor_res, vis, span });
                         }
                         _ => {}
                     }

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

@@ -7,7 +7,7 @@ use rustc_data_structures::stable_map::FxHashMap;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, DefPathHash};
-use rustc_middle::hir::exports::Export;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::exported_symbols::ExportedSymbol;
 use rustc_middle::middle::stability::DeprecationEntry;
 use rustc_middle::ty::query::{ExternProviders, Providers};
@@ -309,7 +309,7 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
                 bfs_queue.push_back(DefId { krate: cnum, index: CRATE_DEF_INDEX });
             }
 
-            let mut add_child = |bfs_queue: &mut VecDeque<_>, child: &Export, parent: DefId| {
+            let mut add_child = |bfs_queue: &mut VecDeque<_>, child: &ModChild, parent: DefId| {
                 if !child.vis.is_public() {
                     return;
                 }
@@ -388,7 +388,7 @@ impl CStore {
         self.get_crate_data(def.krate).get_visibility(def.index)
     }
 
-    pub fn module_children_untracked(&self, def_id: DefId, sess: &Session) -> Vec<Export> {
+    pub fn module_children_untracked(&self, def_id: DefId, sess: &Session) -> Vec<ModChild> {
         let mut result = vec![];
         self.get_crate_data(def_id.krate).for_each_module_child(
             def_id.index,

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1094,7 +1094,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         // code uses it). However, we skip encoding anything relating to child
         // items - we encode information about proc-macros later on.
         let reexports = if !self.is_proc_macro {
-            match tcx.module_exports(local_def_id) {
+            match tcx.module_reexports(local_def_id) {
                 Some(exports) => self.lazy(exports),
                 _ => Lazy::empty(),
             }

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -12,7 +12,7 @@ use rustc_hir::def_id::{DefId, DefIndex, DefPathHash, StableCrateId};
 use rustc_hir::definitions::DefKey;
 use rustc_hir::lang_items;
 use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
-use rustc_middle::hir::exports::Export;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc_middle::mir;
 use rustc_middle::thir;
@@ -350,7 +350,7 @@ enum EntryKind {
     Union(Lazy<VariantData>, ReprOptions),
     Fn(Lazy<FnData>),
     ForeignFn(Lazy<FnData>),
-    Mod(Lazy<[Export]>),
+    Mod(Lazy<[ModChild]>),
     MacroDef(Lazy<MacroDef>),
     ProcMacro(MacroKind),
     Closure,

compiler/rustc_middle/src/hir/mod.rs

@@ -2,7 +2,6 @@
 //!
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
-pub mod exports;
 pub mod map;
 pub mod place;
 

compiler/rustc_middle/src/lib.rs

@@ -84,6 +84,7 @@ pub mod dep_graph;
 pub mod hir;
 pub mod infer;
 pub mod lint;
+pub mod metadata;
 pub mod middle;
 pub mod mir;
 pub mod thir;

compiler/rustc_middle/src/metadata.rs

@@ -0,0 +1,24 @@
+use crate::ty;
+
+use rustc_hir::def::Res;
+use rustc_macros::HashStable;
+use rustc_span::symbol::Ident;
+use rustc_span::Span;
+
+/// This structure is supposed to keep enough data to re-create `NameBinding`s for other crates
+/// during name resolution. Right now the bindings are not recreated entirely precisely so we may
+/// need to add more data in the future to correctly support macros 2.0, for example.
+/// Module child can be either a proper item or a reexport (including private imports).
+/// In case of reexport all the fields describe the reexport item itself, not what it refers to.
+#[derive(Copy, Clone, Debug, TyEncodable, TyDecodable, HashStable)]
+pub struct ModChild {
+    /// Name of the item.
+    pub ident: Ident,
+    /// Resolution result corresponding to the item.
+    /// 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,
+    /// Span of the item.
+    pub span: Span,
+}

compiler/rustc_middle/src/query/mod.rs

@@ -1300,8 +1300,8 @@ rustc_queries! {
         desc { "traits in scope at a block" }
     }
 
-    query module_exports(def_id: LocalDefId) -> Option<&'tcx [Export]> {
-        desc { |tcx| "looking up items exported by `{}`", tcx.def_path_str(def_id.to_def_id()) }
+    query module_reexports(def_id: LocalDefId) -> Option<&'tcx [ModChild]> {
+        desc { |tcx| "looking up reexports of module `{}`", tcx.def_path_str(def_id.to_def_id()) }
     }
 
     query impl_defaultness(def_id: DefId) -> hir::Defaultness {
@@ -1528,8 +1528,8 @@ rustc_queries! {
         desc { "fetching what a crate is named" }
         separate_provide_extern
     }
-    query module_children(def_id: DefId) -> &'tcx [Export] {
-        desc { |tcx| "collecting child items of `{}`", tcx.def_path_str(def_id) }
+    query module_children(def_id: DefId) -> &'tcx [ModChild] {
+        desc { |tcx| "collecting child items of module `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
     }
     query extern_mod_stmt_cnum(def_id: LocalDefId) -> Option<CrateNum> {

compiler/rustc_middle/src/ty/context.rs

@@ -2820,7 +2820,8 @@ pub fn provide(providers: &mut ty::query::Providers) {
     providers.in_scope_traits_map =
         |tcx, id| tcx.hir_crate(()).owners[id].as_ref().map(|owner_info| &owner_info.trait_map);
     providers.resolutions = |tcx, ()| &tcx.untracked_resolutions;
-    providers.module_exports = |tcx, id| tcx.resolutions(()).export_map.get(&id).map(|v| &v[..]);
+    providers.module_reexports =
+        |tcx, id| tcx.resolutions(()).reexport_map.get(&id).map(|v| &v[..]);
     providers.crate_name = |tcx, id| {
         assert_eq!(id, LOCAL_CRATE);
         tcx.crate_name

compiler/rustc_middle/src/ty/mod.rs

@@ -19,7 +19,7 @@ pub use assoc::*;
 pub use generics::*;
 pub use vtable::*;
 
-use crate::hir::exports::ExportMap;
+use crate::metadata::ModChild;
 use crate::mir::{Body, GeneratorLayout};
 use crate::traits::{self, Reveal};
 use crate::ty;
@@ -126,7 +126,7 @@ pub struct ResolverOutputs {
     pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
     pub maybe_unused_trait_imports: FxHashSet<LocalDefId>,
     pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
-    pub export_map: ExportMap,
+    pub reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
     pub glob_map: FxHashMap<LocalDefId, FxHashSet<Symbol>>,
     /// Extern prelude entries. The value is `true` if the entry was introduced
     /// via `extern crate` item and not `--extern` option or compiler built-in.

compiler/rustc_middle/src/ty/query.rs

@@ -1,7 +1,7 @@
 use crate::dep_graph;
-use crate::hir::exports::Export;
 use crate::infer::canonical::{self, Canonical};
 use crate::lint::LintLevelMap;
+use crate::metadata::ModChild;
 use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
 use crate::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use crate::middle::lib_features::LibFeatures;

compiler/rustc_privacy/src/lib.rs

@@ -520,7 +520,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
             let vis = self.tcx.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_exports(module_def_id) {
+        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 let Res::Def(def_kind, def_id) = export.res {
@@ -926,7 +926,7 @@ impl<'tcx> Visitor<'tcx> for EmbargoVisitor<'tcx> {
         // crate module gets processed as well.
         if self.prev_level.is_some() {
             let def_id = self.tcx.hir().local_def_id(id);
-            if let Some(exports) = self.tcx.module_exports(def_id) {
+            if let Some(exports) = self.tcx.module_reexports(def_id) {
                 for export in exports.iter() {
                     if export.vis.is_public() {
                         if let Some(def_id) = export.res.opt_def_id() {

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -26,7 +26,7 @@ use rustc_hir::def::{self, *};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
 use rustc_metadata::creader::LoadedMacro;
 use rustc_middle::bug;
-use rustc_middle::hir::exports::Export;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::ty;
 use rustc_session::cstore::CrateStore;
 use rustc_span::hygiene::{ExpnId, LocalExpnId, MacroKind};
@@ -938,9 +938,9 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
     }
 
     /// Builds the reduced graph for a single item in an external crate.
-    fn build_reduced_graph_for_external_crate_res(&mut self, child: Export) {
+    fn build_reduced_graph_for_external_crate_res(&mut self, child: ModChild) {
         let parent = self.parent_scope.module;
-        let Export { ident, res, vis, span } = child;
+        let ModChild { ident, res, vis, span } = child;
         let res = res.expect_non_local();
         let expansion = self.parent_scope.expansion;
         // Record primary definitions.

compiler/rustc_resolve/src/imports.rs

@@ -15,7 +15,7 @@ use rustc_data_structures::ptr_key::PtrKey;
 use rustc_errors::{pluralize, struct_span_err, Applicability};
 use rustc_hir::def::{self, PartialRes};
 use rustc_hir::def_id::DefId;
-use rustc_middle::hir::exports::Export;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::span_bug;
 use rustc_middle::ty;
 use rustc_session::lint::builtin::{PUB_USE_OF_PRIVATE_EXTERN_CRATE, UNUSED_IMPORTS};
@@ -1409,7 +1409,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             if is_good_import || binding.is_macro_def() {
                 let res = binding.res().expect_non_local();
                 if res != def::Res::Err {
-                    reexports.push(Export { ident, res, span: binding.span, vis: binding.vis });
+                    reexports.push(ModChild { ident, res, vis: binding.vis, span: binding.span });
                 }
             }
         });
@@ -1418,7 +1418,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
             if let Some(def_id) = module.opt_def_id() {
                 // Call to `expect_local` should be fine because current
                 // code is only called for local modules.
-                self.r.export_map.insert(def_id.expect_local(), reexports);
+                self.r.reexport_map.insert(def_id.expect_local(), reexports);
             }
         }
     }

compiler/rustc_resolve/src/lib.rs

@@ -49,7 +49,7 @@ use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
 use rustc_hir::TraitCandidate;
 use rustc_index::vec::IndexVec;
 use rustc_metadata::creader::{CStore, CrateLoader};
-use rustc_middle::hir::exports::ExportMap;
+use rustc_middle::metadata::ModChild;
 use rustc_middle::span_bug;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, MainDefinition, ResolverOutputs};
@@ -927,7 +927,7 @@ pub struct Resolver<'a> {
 
     /// `CrateNum` resolutions of `extern crate` items.
     extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
-    export_map: ExportMap,
+    reexport_map: FxHashMap<LocalDefId, Vec<ModChild>>,
     trait_map: NodeMap<Vec<TraitCandidate>>,
 
     /// A map from nodes to anonymous modules.
@@ -1333,7 +1333,7 @@ impl<'a> Resolver<'a> {
             import_res_map: Default::default(),
             label_res_map: Default::default(),
             extern_crate_map: Default::default(),
-            export_map: FxHashMap::default(),
+            reexport_map: FxHashMap::default(),
             trait_map: NodeMap::default(),
             underscore_disambiguator: 0,
             empty_module,
@@ -1446,7 +1446,7 @@ impl<'a> Resolver<'a> {
         let definitions = self.definitions;
         let visibilities = self.visibilities;
         let extern_crate_map = self.extern_crate_map;
-        let export_map = self.export_map;
+        let reexport_map = self.reexport_map;
         let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
         let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
         let glob_map = self.glob_map;
@@ -1457,7 +1457,7 @@ impl<'a> Resolver<'a> {
             cstore: Box::new(self.crate_loader.into_cstore()),
             visibilities,
             extern_crate_map,
-            export_map,
+            reexport_map,
             glob_map,
             maybe_unused_trait_imports,
             maybe_unused_extern_crates,
@@ -1480,7 +1480,7 @@ impl<'a> Resolver<'a> {
             cstore: Box::new(self.cstore().clone()),
             visibilities: self.visibilities.clone(),
             extern_crate_map: self.extern_crate_map.clone(),
-            export_map: self.export_map.clone(),
+            reexport_map: self.reexport_map.clone(),
             glob_map: self.glob_map.clone(),
             maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
             maybe_unused_extern_crates: self.maybe_unused_extern_crates.clone(),

src/librustdoc/visit_ast.rs

@@ -112,7 +112,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         // is declared but also a reexport of itself producing two exports of the same
         // macro in the same module.
         let mut inserted = FxHashSet::default();
-        for export in self.cx.tcx.module_exports(CRATE_DEF_ID).unwrap_or(&[]) {
+        for export in self.cx.tcx.module_reexports(CRATE_DEF_ID).unwrap_or(&[]) {
             if let Res::Def(DefKind::Macro(_), def_id) = export.res {
                 if let Some(local_def_id) = def_id.as_local() {
                     if self.cx.tcx.has_attr(def_id, sym::macro_export) {