1 files changed, 9 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a171217073e..6574ad2e87d 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -803,6 +803,15 @@ bool Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD) {
   else
     Old = dyn_cast<FunctionDecl>(OldD);
   if (!Old) {
+    if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(OldD)) {
+      Diag(New->getLocation(), diag::err_using_decl_conflict_reverse);
+      Diag(Shadow->getTargetDecl()->getLocation(),
+           diag::note_using_decl_target);
+      Diag(Shadow->getUsingDecl()->getLocation(),
+           diag::note_using_decl) << 0;
+      return true;
+    }
+
     Diag(New->getLocation(), diag::err_redefinition_different_kind)
       << New->getDeclName();
     Diag(OldD->getLocation(), diag::note_previous_definition);