diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index f27330b..bbd3ef3 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -195,6 +195,9 @@
     ModulePrivate = MP;
   }
 
+  /// \brief Determine whether this declaration is hidden from name lookup.
+  bool isHidden() const { return Hidden; }
+  
   /// \brief Determine whether this declaration is a C++ class member.
   bool isCXXClassMember() const {
     const DeclContext *DC = getDeclContext();
diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index 09e1fdc..c2303bc 100644
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -263,6 +263,11 @@
   /// defined.
   unsigned ModulePrivate : 1;
 
+  /// \brief Whether this declaration is hidden from normal name lookup, e.g.,
+  /// because it is was loaded from an AST file is either module-private or
+  /// because its submodule has not been made visible.
+  unsigned Hidden : 1;
+  
   /// IdentifierNamespace - This specifies what IDNS_* namespace this lives in.
   unsigned IdentifierNamespace : 12;
 
@@ -290,7 +295,7 @@
       Loc(L), DeclKind(DK), InvalidDecl(0),
       HasAttrs(false), Implicit(false), Used(false), Referenced(false),
       TopLevelDeclInObjCContainer(false), Access(AS_none), FromASTFile(0),
-      ModulePrivate(0),
+      ModulePrivate(0), Hidden(0),
       IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
       HasCachedLinkage(0)
   {
@@ -301,7 +306,7 @@
     : NextDeclInContext(0), DeclKind(DK), InvalidDecl(0),
       HasAttrs(false), Implicit(false), Used(false), Referenced(false),
       TopLevelDeclInObjCContainer(false), Access(AS_none), FromASTFile(0),
-      ModulePrivate(0),
+      ModulePrivate(0), Hidden(0),
       IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
       HasCachedLinkage(0)
   {
diff --git a/include/clang/Sema/Lookup.h b/include/clang/Sema/Lookup.h
index 6486e53..1c24d20 100644
--- a/include/clang/Sema/Lookup.h
+++ b/include/clang/Sema/Lookup.h
@@ -275,9 +275,8 @@
   /// \brief Determine whether the given declaration is visible to the
   /// program.
   static bool isVisible(NamedDecl *D) {
-    // So long as this declaration is not module-private or was parsed as
-    // part of this translation unit (i.e., in the module), it's visible.
-    if (!D->isModulePrivate() || !D->isFromASTFile())
+    // If this declaration is not hidden, it's visible.
+    if (!D->isHidden())
       return true;
     
     // FIXME: We should be allowed to refer to a module-private name from