1 files changed, 16 insertions, 3 deletions
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index a46d2d21d2f..9b51f3dae52 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -3474,10 +3474,23 @@ void ASTReader::makeModuleVisible(Module *Mod,
 /// visible.
 void ASTReader::mergeDefinitionVisibility(NamedDecl *Def,
                                           NamedDecl *MergedDef) {
+  // FIXME: This doesn't correctly handle the case where MergedDef is visible
+  // in modules other than its owning module. We should instead give the
+  // ASTContext a list of merged definitions for Def.
   if (Def->isHidden()) {
     // If MergedDef is visible or becomes visible, make the definition visible.
-    getContext().mergeDefinitionIntoModulesOf(Def, MergedDef);
-    PendingMergedDefinitionsToDeduplicate.insert(Def);
+    if (!MergedDef->isHidden())
+      Def->Hidden = false;
+    else if (getContext().getLangOpts().ModulesLocalVisibility) {
+      getContext().mergeDefinitionIntoModule(
+          Def, MergedDef->getImportedOwningModule(),
+          /*NotifyListeners*/ false);
+      PendingMergedDefinitionsToDeduplicate.insert(Def);
+    } else {
+      auto SubmoduleID = MergedDef->getOwningModuleID();
+      assert(SubmoduleID && "hidden definition in no module");
+      HiddenNamesMap[getSubmodule(SubmoduleID)].push_back(Def);
+    }
   }
 }
 
@@ -8608,7 +8621,7 @@ void ASTReader::finishPendingActions() {
       const FunctionDecl *Defn = nullptr;
       if (!getContext().getLangOpts().Modules || !FD->hasBody(Defn))
         FD->setLazyBody(PB->second);
-      else if (FD != Defn)
+      else
         mergeDefinitionVisibility(const_cast<FunctionDecl*>(Defn), FD);
       continue;
     }