diff --git a/include/nameof.hpp b/include/nameof.hpp
index 88dd663..facbc9b 100644
--- a/include/nameof.hpp
+++ b/include/nameof.hpp
@@ -456,12 +456,12 @@ template <typename T,
 NAMEOF_CONSTEXPR cstring NameofEnum(T value) {
 #if defined(__clang__) || defined(_MSC_VER)
   return detail::NameofPretty(
-      std::is_unsigned<std::underlying_type<T>::type>::value
+      std::is_unsigned<typename std::underlying_type<T>::type>::value
           ? detail::NameofEnumImpl<T, 0>{}(static_cast<int>(value))
           : detail::NameofEnumImpl<T, -NAMEOF_ENUM_MAX_SEARCH_DEPTH>{}(static_cast<int>(value)),
       false);
 #elif defined(__GNUC__)
-  return std::is_unsigned<std::underlying_type<T>::type>::value
+  return std::is_unsigned<typename std::underlying_type<T>::type>::value
              ? detail::NameofEnumImpl<T, 0>{}(static_cast<int>(value))
              : detail::NameofEnumImpl<T, -NAMEOF_ENUM_MAX_SEARCH_DEPTH>{}(static_cast<int>(value));
 #else