From 66f24393cc0a1167c50e174f59510f0fe5cf24c9 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Wed, 6 Dec 2023 16:21:16 +0300
Subject: [PATCH] Feed visibilities for import stems and opaque types too

---
 compiler/rustc_ast_lowering/src/lib.rs        |  6 +++++-
 compiler/rustc_privacy/src/lib.rs             | 21 ++++---------------
 .../rustc_resolve/src/build_reduced_graph.rs  |  8 ++++---
 3 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index d435082e12190..c8d17e2ab41c4 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -62,7 +62,7 @@ use rustc_hir::{ConstArg, GenericArg, ItemLocalId, ParamName, TraitCandidate};
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::{
     span_bug,
-    ty::{ResolverAstLowering, TyCtxt},
+    ty::{ResolverAstLowering, TyCtxt, Visibility},
 };
 use rustc_session::parse::{add_feature_diagnostics, feature_err};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
@@ -1624,6 +1624,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         );
         debug!(?opaque_ty_def_id);
 
+        // Meaningless, but provided so that all items have visibilities.
+        let parent_mod = self.tcx.parent_module_from_def_id(opaque_ty_def_id).to_def_id();
+        self.tcx.feed_local_def_id(opaque_ty_def_id).visibility(Visibility::Restricted(parent_mod));
+
         // Map from captured (old) lifetime to synthetic (new) lifetime.
         // Used to resolve lifetimes in the bounds of the opaque.
         let mut captured_to_synthesized_mapping = FxHashMap::default();
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 12a6807b1d5ff..777d893ba3eb4 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -1774,25 +1774,12 @@ pub fn provide(providers: &mut Providers) {
 }
 
 fn visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility<DefId> {
-    local_visibility(tcx, def_id).to_def_id()
-}
-
-fn local_visibility(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Visibility {
-    let hir_id = tcx.local_def_id_to_hir_id(def_id);
-    match tcx.hir().get(hir_id) {
+    match tcx.hir().get_by_def_id(def_id) {
         // Unique types created for closures participate in type privacy checking.
         // They have visibilities inherited from the module they are defined in.
-        Node::Expr(hir::Expr { kind: hir::ExprKind::Closure{..}, .. })
-        // - AST lowering creates dummy `use` items which don't
-        //   get their entries in the resolver's visibility table.
-        // - AST lowering also creates opaque type items with inherited visibilities.
-        //   Visibility on them should have no effect, but to avoid the visibility
-        //   query failing on some items, we provide it for opaque types as well.
-        | Node::Item(hir::Item {
-            kind: hir::ItemKind::Use(_, hir::UseKind::ListStem)
-                | hir::ItemKind::OpaqueTy(..),
-            ..
-        }) => ty::Visibility::Restricted(tcx.parent_module(hir_id).to_local_def_id()),
+        Node::Expr(hir::Expr { kind: hir::ExprKind::Closure { .. }, .. }) => {
+            ty::Visibility::Restricted(tcx.parent_module_from_def_id(def_id).to_def_id())
+        }
         _ => span_bug!(
             tcx.def_span(def_id),
             "visibility table unexpectedly missing a def-id: {:?}",
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index 9c09bb38a3f14..cc553d916806c 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -399,6 +399,10 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
             parent_prefix, use_tree, nested
         );
 
+        if nested {
+            self.r.feed_visibility(self.r.local_def_id(id), vis);
+        }
+
         let mut prefix_iter = parent_prefix
             .iter()
             .cloned()
@@ -437,8 +441,6 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                 let mut source = module_path.pop().unwrap();
                 let mut type_ns_only = false;
 
-                self.r.feed_visibility(self.r.local_def_id(id), vis);
-
                 if nested {
                     // Correctly handle `self`
                     if source.ident.name == kw::SelfLower {
@@ -552,7 +554,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                     max_vis: Cell::new(None),
                     id,
                 };
-                self.r.feed_visibility(self.r.local_def_id(id), vis);
+
                 self.add_import(prefix, kind, use_tree.span, item, root_span, item.id, vis);
             }
             ast::UseTreeKind::Nested(ref items) => {