Use contiguous_range when available

Author: user202729

include/fmt/base.h

@@ -20,6 +20,10 @@
 #  include <type_traits>  // std::enable_if
 #endif
 
+#if defined(__cpp_lib_ranges)
+#include <ranges>
+#endif
+
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
 #define FMT_VERSION 120101
 
@@ -588,7 +592,11 @@ template <typename T> class basic_appender;
 using appender = basic_appender<char>;
 
 // Checks whether T is a container with contiguous storage.
+#if defined(__cpp_lib_ranges)
+template <typename T> struct is_contiguous : std::bool_constant<std::ranges::contiguous_range<T>> {};
+#else
 template <typename T> struct is_contiguous : std::false_type {};
+#endif
 
 class context;
 template <typename OutputIt, typename Char> class generic_context;