removed changes from master branch

dune/common/typetraits.hh

@@ -531,52 +531,6 @@ namespace Dune
 
 #endif // defined(DOXYGEN) or HAVE_IS_INDEXABLE_SUPPORT
 
-  namespace detail
-  {
-    /// @internal
-    /// helper to make void_t work with gcc
-    template <class...>
-    struct voider
-    {
-      using type = void;
-    };
-
-    template <class,class = void> class Real_t;
-  }
-
-  template <class> struct FieldTraits;
-
-  /**
-   * @brief Is void for all valid input types.
-   *
-   * The workhorse for C++11 SFINAE-techniques.
-   */
-  template <class... Types>
-  using void_t = typename detail::voider<Types...>::type;
-
-  //! Convenient access to Type::field_type.
-  template <class Type>
-  using field_t = typename Type::field_type;
-
-  //! Convenient access to Type::real_type, resp. FieldTraits<Type::field_type>::real_type.
-  template <class Type>
-  using real_t = typename detail::Real_t<Type>::type;
-
-
-  namespace detail
-  {
-    template <class Type,class>
-    struct Real_t
-    {
-      using type = typename FieldTraits<Type>::real_type;
-    };
-
-    template <class Type>
-    struct Real_t< Type , void_t< field_t<Type> > >
-    {
-      using type = typename Real_t< field_t<Type> >::type;
-    };
-  }
 
   /** @} */
 }