diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index e26e5190..39b5d33c 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -283,6 +283,7 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
 #define FMT_NOMACRO
 
 namespace detail {
+template <typename T = void> struct null {};
 inline null<> localtime_r FMT_NOMACRO(...) { return null<>(); }
 inline null<> localtime_s(...) { return null<>(); }
 inline null<> gmtime_r(...) { return null<>(); }
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 06f7ea12..bbaef4b0 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1135,8 +1135,6 @@ class utf8_to_utf16 {
   std::wstring str() const { return {&buffer_[0], size()}; }
 };
 
-template <typename T = void> struct null {};
-
 namespace dragonbox {
 
 // Type-specific information that Dragonbox uses.