diff --git a/clang/test/Modules/redecl-merge.m b/clang/test/Modules/redecl-merge.m
index 40c6aaf0fffa..d62d504868c5 100644
--- a/clang/test/Modules/redecl-merge.m
+++ b/clang/test/Modules/redecl-merge.m
@@ -1,5 +1,6 @@
 // RUN: rm -rf %t
 // RUN: %clang_cc1 -fmodule-cache-path %t -I %S/Inputs %s -verify
+// RUN: %clang_cc1 -x objective-c++ -fmodule-cache-path %t -I %S/Inputs %s -verify
 __import_module__ redecl_merge_left;
 __import_module__ redecl_merge_right;