diff --git a/format.cc b/format.cc
index e7b3c749..a3b05724 100644
--- a/format.cc
+++ b/format.cc
@@ -103,11 +103,11 @@ using fmt::internal::Arg;
 
 // Dummy implementations of strerror_r and strerror_s called if corresponding
 // system functions are not available.
-static inline fmt::internal::None<void> strerror_r(int, char *, ...) {
-  return fmt::internal::None<void>();
+static inline fmt::internal::None<> strerror_r(int, char *, ...) {
+  return fmt::internal::None<>();
 }
-static inline fmt::internal::None<void> strerror_s(char *, std::size_t, ...) {
-  return fmt::internal::None<void>();
+static inline fmt::internal::None<> strerror_s(char *, std::size_t, ...) {
+  return fmt::internal::None<>();
 }
 
 namespace {
@@ -189,7 +189,7 @@ int safe_strerror(
     }
 
     // Handle the case when strerror_r is not available.
-    int handle(fmt::internal::None<void>) {
+    int handle(fmt::internal::None<>) {
       return fallback(strerror_s(buffer_, buffer_size_, error_code_));
     }
 
@@ -201,7 +201,7 @@ int safe_strerror(
     }
 
     // Fallback to strerror if strerror_r and strerror_s are not available.
-    int fallback(fmt::internal::None<void>) {
+    int fallback(fmt::internal::None<>) {
       errno = 0;
       buffer_ = strerror(error_code_);
       return errno;
diff --git a/format.h b/format.h
index fb414ca3..6e57047b 100644
--- a/format.h
+++ b/format.h
@@ -749,7 +749,7 @@ struct Arg : Value {
   Type type;
 };
 
-template <typename T>
+template <typename T = void>
 struct None {};
 
 // A helper class template to enable or disable overloads taking wide