resolve: Preserve reexport chains in ModChildren

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -991,7 +991,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
  _ => false,
  };
 
- ModChild { ident, res, vis, span, macro_rules }
+ ModChild { ident, res, vis, span, macro_rules, reexport_chain: Default::default() }
  }
 
  /// Iterates over all named children of the given module,

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1327,8 +1327,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
  }
  }));
 
- if let Some(reexports) = tcx.module_reexports(local_def_id) {
-  assert!(!reexports.is_empty());
+ let reexports = tcx.module_reexports(local_def_id);
+ if !reexports.is_empty() {
  record_array!(self.tables.module_reexports[def_id] <- reexports);
  }
  }

compiler/rustc_middle/src/arena.rs

@@ -119,6 +119,7 @@ macro_rules! arena_types {
  [] external_constraints: rustc_middle::traits::solve::ExternalConstraintsData<'tcx>,
  [decode] doc_link_resolutions: rustc_hir::def::DocLinkResMap,
  [] closure_kind_origin: (rustc_span::Span, rustc_middle::hir::place::Place<'tcx>),
+ [] mod_child: rustc_middle::metadata::ModChild,
  ]);
  )
 }

compiler/rustc_middle/src/metadata.rs

@@ -5,13 +5,34 @@ use rustc_macros::HashStable;
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
+use smallvec::SmallVec;
+
+/// A simplified version of `ImportKind` from resolve.
+/// `DefId`s here correspond to `use` and `extern crate` items themselves, not their targets.
+#[derive(Clone, Copy, Debug, TyEncodable, TyDecodable, HashStable)]
+pub enum Reexport {
+ Single(DefId),
+ Glob(DefId),
+ ExternCrate(DefId),
+ MacroUse,
+ MacroExport,
+}
+
+impl Reexport {
+ pub fn id(self) -> Option<DefId> {
+ match self {
+ Reexport::Single(id) | Reexport::Glob(id) | Reexport::ExternCrate(id) => Some(id),
+ Reexport::MacroUse | Reexport::MacroExport => None,
+ }
+ }
+}
 
 /// 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)]
+#[derive(Debug, TyEncodable, TyDecodable, HashStable)]
 pub struct ModChild {
  /// Name of the item.
  pub ident: Ident,
@@ -24,4 +45,7 @@ pub struct ModChild {
  pub span: Span,
  /// A proper `macro_rules` item (not a reexport).
  pub macro_rules: bool,
+ /// Reexport chain linking this module child to its original reexported item.
+ /// Empty if the module child is a proper item.
+ pub reexport_chain: SmallVec<[Reexport; 2]>,
 }

compiler/rustc_middle/src/query/erase.rs

@@ -235,7 +235,6 @@ trivial! {
  rustc_hir::OwnerId,
  rustc_hir::Upvar,
  rustc_index::bit_set::FiniteBitSet<u32>,
- rustc_middle::metadata::ModChild,
  rustc_middle::middle::dependency_format::Linkage,
  rustc_middle::middle::exported_symbols::SymbolExportInfo,
  rustc_middle::middle::resolve_bound_vars::ObjectLifetimeDefault,

compiler/rustc_middle/src/query/mod.rs

@@ -1510,7 +1510,7 @@ rustc_queries! {
  desc { "getting traits in scope at a block" }
  }
 
- query module_reexports(def_id: LocalDefId) -> Option<&'tcx [ModChild]> {
+ query module_reexports(def_id: LocalDefId) -> &'tcx [ModChild] {
  desc { |tcx| "looking up reexports of module `{}`", tcx.def_path_str(def_id.to_def_id()) }
  }
 

compiler/rustc_middle/src/ty/context.rs

@@ -2502,7 +2502,7 @@ pub struct DeducedParamAttrs {
 
 pub fn provide(providers: &mut ty::query::Providers) {
  providers.module_reexports =
- |tcx, id| tcx.resolutions(()).reexport_map.get(&id).map(|v| &v[..]);
+ |tcx, id| tcx.resolutions(()).reexport_map.get(&id).map_or(&[], |v| &v[..]);
  providers.maybe_unused_trait_imports =
  |tcx, ()| &tcx.resolutions(()).maybe_unused_trait_imports;
  providers.names_imported_by_glob_use = |tcx, id| {

compiler/rustc_privacy/src/lib.rs

@@ -515,16 +515,12 @@ impl<'tcx> EmbargoVisitor<'tcx> {
  let vis = self.tcx.local_visibility(item_id.owner_id.def_id);
  self.update_macro_reachable_def(item_id.owner_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, 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.local_visibility(def_id);
- self.update_macro_reachable_def(def_id, def_kind, vis, defining_mod);
- }
- }
- }
+ for export in self.tcx.module_reexports(module_def_id) {
+ if export.vis.is_accessible_from(defining_mod, self.tcx)
+ && let Res::Def(def_kind, def_id) = export.res
+ && let Some(def_id) = def_id.as_local() {
+ let vis = self.tcx.local_visibility(def_id);
+ self.update_macro_reachable_def(def_id, def_kind, vis, defining_mod);
  }
  }
  }

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -931,7 +931,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
  /// Builds the reduced graph for a single item in an external crate.
  fn build_reduced_graph_for_external_crate_res(&mut self, child: ModChild) {
  let parent = self.parent_scope.module;
- let ModChild { ident, res, vis, span, macro_rules } = child;
+ let ModChild { ident, res, vis, span, macro_rules, .. } = child;
  let res = res.expect_non_local();
  let expansion = self.parent_scope.expansion;
  // Record primary definitions.

compiler/rustc_resolve/src/imports.rs

@@ -17,6 +17,7 @@ use rustc_data_structures::intern::Interned;
 use rustc_errors::{pluralize, struct_span_err, Applicability, MultiSpan};
 use rustc_hir::def::{self, DefKind, PartialRes};
 use rustc_middle::metadata::ModChild;
+use rustc_middle::metadata::Reexport;
 use rustc_middle::span_bug;
 use rustc_middle::ty;
 use rustc_session::lint::builtin::{
@@ -27,6 +28,7 @@ use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::LocalExpnId;
 use rustc_span::symbol::{kw, Ident, Symbol};
 use rustc_span::Span;
+use smallvec::SmallVec;
 
 use std::cell::Cell;
 use std::{mem, ptr};
@@ -190,6 +192,17 @@ impl<'a> Import<'a> {
  ImportKind::MacroUse | ImportKind::MacroExport => None,
  }
  }
+
+ fn simplify(&self, r: &Resolver<'_, '_>) -> Reexport {
+ let to_def_id = |id| r.local_def_id(id).to_def_id();
+ match self.kind {
+ ImportKind::Single { id, .. } => Reexport::Single(to_def_id(id)),
+ ImportKind::Glob { id, .. } => Reexport::Glob(to_def_id(id)),
+ ImportKind::ExternCrate { id, .. } => Reexport::ExternCrate(to_def_id(id)),
+ ImportKind::MacroUse => Reexport::MacroUse,
+ ImportKind::MacroExport => Reexport::MacroExport,
+ }
+ }
 }
 
 /// Records information about the resolution of a name in a namespace of a module.
@@ -1252,12 +1265,20 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
 
  module.for_each_child(self, |this, ident, _, binding| {
  if let Some(res) = this.is_reexport(binding) {
+ let mut reexport_chain = SmallVec::new();
+ let mut next_binding = binding;
+ while let NameBindingKind::Import { binding, import, .. } = next_binding.kind {
+ reexport_chain.push(import.simplify(this));
+ next_binding = binding;
+ }
+
  reexports.push(ModChild {
  ident,
  res,
  vis: binding.vis,
  span: binding.span,
  macro_rules: false,
+ reexport_chain,
  });
  }
  });

library/std/src/collections/mod.rs

@@ -416,8 +416,10 @@ pub use alloc_crate::collections::{BTreeMap, BTreeSet, BinaryHeap};
 pub use alloc_crate::collections::{LinkedList, VecDeque};
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(inline)]
 pub use self::hash_map::HashMap;
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(inline)]
 pub use self::hash_set::HashSet;
 
 #[stable(feature = "try_reserve", since = "1.57.0")]

src/librustdoc/clean/inline.rs

@@ -153,7 +153,6 @@ pub(crate) fn try_inline_glob(
  let reexports = cx
  .tcx
  .module_reexports(current_mod)
- .unwrap_or_default()
  .iter()
  .filter_map(|child| child.res.opt_def_id())
  .collect();
@@ -558,7 +557,7 @@ fn build_module_items(
  // If we're re-exporting a re-export it may actually re-export something in
  // two namespaces, so the target may be listed twice. Make sure we only
  // visit each node at most once.
- for &item in cx.tcx.module_children(did).iter() {
+ for item in cx.tcx.module_children(did).iter() {
  if item.vis.is_public() {
  let res = item.res.expect_non_local();
  if let Some(def_id) = res.opt_def_id()