5 files changed, 36 insertions, 4 deletions
diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index 5dccaac020..d8b63611fd 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -59,6 +59,11 @@ void *Decl::AllocateDeserializedDecl(const ASTContext &Context,
   return Result;
 }
 
+Module *Decl::getOwningModuleSlow() const {
+  assert(isFromASTFile() && "Not from AST file?");
+  return getASTContext().getExternalSource()->getModule(getOwningModuleID());
+}
+
 const char *Decl::getDeclKindName() const {
   switch (DeclKind) {
   default: llvm_unreachable("Declaration not in DeclNodes.inc!");
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index f31301c6e9..5b2be91967 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -1201,3 +1201,9 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
   LastModuleImportResult = ModuleLoadResult(Module, false);
   return LastModuleImportResult;
 }
+
+void CompilerInstance::makeModuleVisible(Module *Mod,
+                                         Module::NameVisibilityKind Visibility){
+  ModuleManager->makeModuleVisible(Mod, Visibility);
+}
+
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 0cf1238220..c3a2ad1123 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -11173,6 +11173,18 @@ DeclResult Sema::ActOnModuleImport(SourceLocation AtLoc,
   return Import;
 }
 
+void Sema::createImplicitModuleImport(SourceLocation Loc, Module *Mod) {
+  // Create the implicit import declaration.
+  TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
+  ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
+                                                   Loc, Mod, Loc);
+  TU->addDecl(ImportD);
+  Consumer.HandleImplicitImportDecl(ImportD);
+
+  // Make the module visible.
+  PP.getModuleLoader().makeModuleVisible(Mod, Module::AllVisible);
+}
+
 void Sema::ActOnPragmaRedefineExtname(IdentifierInfo* Name,
                                       IdentifierInfo* AliasName,
                                       SourceLocation PragmaLoc,
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 60db55aff3..59c1dea8ff 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -4392,9 +4392,14 @@ bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
       // repeating the diagnostic.
       // FIXME: Add a Fix-It that imports the corresponding module or includes
       // the header.
-      if (isSFINAEContext() || HiddenDefinitions.insert(Def)) {
-        Diag(Loc, diag::err_module_private_definition) << T;
-        Diag(Def->getLocation(), diag::note_previous_definition);
+      Module *Owner = Def->getOwningModule();
+      Diag(Loc, diag::err_module_private_definition)
+        << T << Owner->getFullModuleName();
+      Diag(Def->getLocation(), diag::note_previous_definition);
+
+      if (!isSFINAEContext()) {
+        // Recover by implicitly importing this module.
+        createImplicitModuleImport(Loc, Owner);
       }
     }
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index a4436d1671..986eee1c95 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -6200,7 +6200,11 @@ Module *ASTReader::getSubmodule(SubmoduleID GlobalID) {
   
   return SubmodulesLoaded[GlobalID - NUM_PREDEF_SUBMODULE_IDS];
 }
-                               
+
+Module *ASTReader::getModule(unsigned ID) {
+  return getSubmodule(ID);
+}
+
 Selector ASTReader::getLocalSelector(ModuleFile &M, unsigned LocalID) {
   return DecodeSelector(getGlobalSelectorID(M, LocalID));
 }