diff --git a/include/fmt/base.h b/include/fmt/base.h
index 774f260d..72756344 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -2755,7 +2755,7 @@ template <typename... T> struct fstring {
     static_assert(count<(is_view<remove_cvref_t<T>>::value &&
                          std::is_reference<T>::value)...>() == 0,
                   "passing views as lvalues is disallowed");
-#ifdef FMT_USE_CONSTEVAL
+#if FMT_USE_CONSTEVAL
     parse_format_string<char>(s, checker(s, arg_pack()));
 #endif
 #ifdef FMT_ENFORCE_COMPILE_STRING