diff --git a/include/fmt/base.h b/include/fmt/base.h
index 64c6a07b..707b0ad1 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -2819,11 +2819,11 @@ template <typename Char, typename... T> class fstring {
 template <typename... T> using format_string = typename fstring<char, T...>::t;
 
 template <typename T, typename Char = char>
-using is_formattable = bool_constant<!std::is_base_of<
-    detail::unformattable,
-    detail::mapped_t<
-        conditional_t<std::is_same<T, void>::value, detail::unformattable, T>,
-        Char>>::value>;
+using is_formattable = bool_constant<
+    !std::is_base_of<detail::unformattable,
+                     detail::mapped_t<conditional_t<std::is_void<T>::value,
+                                                    detail::unformattable, T>,
+                                      Char>>::value>;
 
 #ifdef __cpp_concepts
 template <typename T, typename Char = char>