Privacy: small cleanups

compiler/rustc_privacy/src/lib.rs

diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index de5c003..9cf0576 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -788,8 +788,7 @@ fn enqueue_def_id(&mut self, def_id: LocalDefId) {
             }
 
             DefKind::AssocConst { .. } | DefKind::AssocFn | DefKind::AssocTy => {
-                // FIXME: `EmbargoVisitor` can't check assoc items(see `check_def_id`).
-                // Let's traverse the whole impl/trait.
+                // Traverse the whole impl/trait.
                 self.ev.queue.insert(self.ev.tcx.local_parent(def_id));
             }
 
@@ -843,6 +842,10 @@ fn visit_def_id(&mut self, def_id: DefId, _kind: &str, _descr: &dyn fmt::Display
             // All effective visibilities except `reachable_through_impl_trait` are limited to
             // nominal visibility. If any type or trait is leaked farther than that, it will
             // produce type privacy errors on any use, so we don't consider it leaked.
+            //
+            // FIXME: If self.level == Level::Reachable and self.ev == (priv, priv, priv, pub),
+            // then the effective visibility of def_id wouldn't be updated at level
+            // `ReachableThroughImplTrait` due to max_vis. Could this lead to a privacy violation?
             let max_vis = (self.level != Level::ReachableThroughImplTrait)
                 .then(|| self.ev.tcx.local_visibility(def_id));
             if self.ev.update_eff_vis(def_id, self.effective_vis, max_vis, self.level) {

compiler/rustc_resolve/src/effective_visibilities.rs

diff --git a/compiler/rustc_resolve/src/effective_visibilities.rs b/compiler/rustc_resolve/src/effective_visibilities.rs
index 44f14fa..8bb0a0c 100644
--- a/compiler/rustc_resolve/src/effective_visibilities.rs
+++ b/compiler/rustc_resolve/src/effective_visibilities.rs
@@ -334,11 +334,7 @@ fn update_macro_reachable_def(
                 }
             }
             DefKind::Struct | DefKind::Union => {
-                self.r
-                    .macro_reachable_adts
-                    .entry(def_id)
-                    .or_insert_with(Default::default)
-                    .insert(module);
+                self.r.macro_reachable_adts.entry(def_id).or_default().insert(module);
             }
             _ => {}
         }