diff --git a/samples/monster_generated.h b/samples/monster_generated.h
index d9d64793d..b31a8ed5c 100644
--- a/samples/monster_generated.h
+++ b/samples/monster_generated.h
@@ -119,8 +119,9 @@ struct EquipmentUnion {
   void Reset();
 
 #ifndef FLATBUFFERS_CPP98_STL
-  template <typename T, typename RT = typename std::remove_reference<T>::type>
+  template <typename T>
   void Set(T&& val) {
+    using RT = typename std::remove_reference<T>::type;
     Reset();
     type = EquipmentTraits<typename RT::TableType>::enum_value;
     if (type != Equipment_NONE) {
diff --git a/src/idl_gen_cpp.cpp b/src/idl_gen_cpp.cpp
index 0c964d4bc..d3dfeb10e 100644
--- a/src/idl_gen_cpp.cpp
+++ b/src/idl_gen_cpp.cpp
@@ -1096,8 +1096,9 @@ class CppGenerator : public BaseGenerator {
       code_ += "";
       if (!enum_def.uses_multiple_type_instances) {
         code_ += "#ifndef FLATBUFFERS_CPP98_STL";
-        code_ += "  template <typename T, typename RT = typename std::remove_reference<T>::type>";
+        code_ += "  template <typename T>";
         code_ += "  void Set(T&& val) {";
+        code_ += "    using RT = typename std::remove_reference<T>::type;";
         code_ += "    Reset();";
         code_ += "    type = {{NAME}}Traits<typename RT::TableType>::enum_value;";
         code_ += "    if (type != {{NONE}}) {";
diff --git a/tests/monster_test_generated.h b/tests/monster_test_generated.h
index a55a42754..3a440073f 100644
--- a/tests/monster_test_generated.h
+++ b/tests/monster_test_generated.h
@@ -207,8 +207,9 @@ struct AnyUnion {
   void Reset();
 
 #ifndef FLATBUFFERS_CPP98_STL
-  template <typename T, typename RT = typename std::remove_reference<T>::type>
+  template <typename T>
   void Set(T&& val) {
+    using RT = typename std::remove_reference<T>::type;
     Reset();
     type = AnyTraits<typename RT::TableType>::enum_value;
     if (type != Any_NONE) {
@@ -348,8 +349,9 @@ struct AnyUniqueAliasesUnion {
   void Reset();
 
 #ifndef FLATBUFFERS_CPP98_STL
-  template <typename T, typename RT = typename std::remove_reference<T>::type>
+  template <typename T>
   void Set(T&& val) {
+    using RT = typename std::remove_reference<T>::type;
     Reset();
     type = AnyUniqueAliasesTraits<typename RT::TableType>::enum_value;
     if (type != AnyUniqueAliases_NONE) {