diff --git a/include/etl/type_traits.h b/include/etl/type_traits.h
index 404fe3fa..85a21292 100644
--- a/include/etl/type_traits.h
+++ b/include/etl/type_traits.h
@@ -650,12 +650,12 @@ namespace etl
 
   //***************************************************************************
   /// add_lvalue_reference
-  template <typename T> struct add_lvalue_reference { using type = T & ; };
-  template <typename T> struct add_lvalue_reference<T&> { using type = T & ; };
-  template <>           struct add_lvalue_reference<void> { using type = void; };
-  template <>           struct add_lvalue_reference<const void> { using type = const void; };
-  template <>           struct add_lvalue_reference<volatile void> { using type = volatile void; };
-  template <>           struct add_lvalue_reference<const volatile void> { using type = const volatile void; };
+  template <typename T> struct add_lvalue_reference { typedef T& type; };
+  template <typename T> struct add_lvalue_reference<T&> { typedef T& type; };
+  template <>           struct add_lvalue_reference<void> { typedef void type; };
+  template <>           struct add_lvalue_reference<const void> { typedef const void type; };
+  template <>           struct add_lvalue_reference<volatile void> { typedef volatile void type; };
+  template <>           struct add_lvalue_reference<const volatile void> { typedef const volatile void type; };
 
 #if ETL_CPP14_SUPPORTED
   template <typename T>
@@ -1321,10 +1321,10 @@ namespace etl
   /// Template to determine if a type is one of a specified list.
   ///\ingroup types
   template <typename T,
-            typename T1, typename T2 = void, typename T3 = void, typename T4 = void, 
-            typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void, 
-            typename T9 = void, typename T10 = void, typename T11 = void, typename T12 = void, 
-            typename T13 = void, typename T14 = void, typename T15 = void, typename T16 = void, 
+            typename T1, typename T2 = void, typename T3 = void, typename T4 = void,
+            typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void,
+            typename T9 = void, typename T10 = void, typename T11 = void, typename T12 = void,
+            typename T13 = void, typename T14 = void, typename T15 = void, typename T16 = void,
             typename T17 = void>
   struct is_one_of
   {
diff --git a/include/etl/type_traits_generator.h b/include/etl/type_traits_generator.h
index cb90ba6c..e3696860 100644
--- a/include/etl/type_traits_generator.h
+++ b/include/etl/type_traits_generator.h
@@ -662,12 +662,12 @@ namespace etl
 
   //***************************************************************************
   /// add_lvalue_reference
-  template <typename T> struct add_lvalue_reference { using type = T & ; };
-  template <typename T> struct add_lvalue_reference<T&> { using type = T & ; };
-  template <>           struct add_lvalue_reference<void> { using type = void; };
-  template <>           struct add_lvalue_reference<const void> { using type = const void; };
-  template <>           struct add_lvalue_reference<volatile void> { using type = volatile void; };
-  template <>           struct add_lvalue_reference<const volatile void> { using type = const volatile void; };
+  template <typename T> struct add_lvalue_reference { typedef T& type; };
+  template <typename T> struct add_lvalue_reference<T&> { typedef T& type; };
+  template <>           struct add_lvalue_reference<void> { typedef void type; };
+  template <>           struct add_lvalue_reference<const void> { typedef const void type; };
+  template <>           struct add_lvalue_reference<volatile void> { typedef volatile void type; };
+  template <>           struct add_lvalue_reference<const volatile void> { typedef const volatile void type; };
 
 #if ETL_CPP14_SUPPORTED
   template <typename T>