Add FMT_ENABLE_IF_T

for definitions of functions which declared using FMT_ENABLE_IF

include/fmt/chrono.h

@@ -376,13 +376,11 @@ struct chrono_format_checker {
   FMT_NORETURN void on_tz_name() { report_no_date(); }
 };
 
-template <typename T,
-          typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
 inline bool isnan(T) {
   return false;
 }
-template <typename T, typename std::enable_if<std::is_floating_point<T>::value,
-                                              int>::type = 0>
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
 inline bool isnan(T value) {
   return std::isnan(value);
 }
@@ -394,13 +392,11 @@ template <typename T> inline int to_int(T value) {
   return static_cast<int>(value);
 }
 
-template <typename T,
-          typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
+template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
 inline T mod(T x, int y) {
   return x % y;
 }
-template <typename T, typename std::enable_if<std::is_floating_point<T>::value,
-                                              int>::type = 0>
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
 inline T mod(T x, int y) {
   return std::fmod(x, y);
 }

include/fmt/core.h

@@ -227,7 +227,8 @@
 
 // An enable_if helper to be used in template parameters. enable_if in template
 // parameters results in much shorter symbols: https://godbolt.org/z/sWw4vP.
-#define FMT_ENABLE_IF(...) typename std::enable_if<__VA_ARGS__, int>::type = 0
+#define FMT_ENABLE_IF_T(...) typename std::enable_if<__VA_ARGS__, int>::type
+#define FMT_ENABLE_IF(...) FMT_ENABLE_IF_T(__VA_ARGS__) = 0
 
 FMT_BEGIN_NAMESPACE
 namespace internal {

include/fmt/format-inl.h

@@ -682,8 +682,7 @@ template <int GRISU_VERSION> struct grisu_shortest_handler {
   }
 };
 
-template <typename Double, typename std::enable_if<
-                               sizeof(Double) == sizeof(uint64_t), int>::type>
+template <typename Double, FMT_ENABLE_IF_T(sizeof(Double) == sizeof(uint64_t))>
 FMT_FUNC bool grisu_format(Double value, buffer<char>& buf, int precision,
                            unsigned options, int& exp) {
   FMT_ASSERT(value >= 0, "value is negative");

include/fmt/format.h

@@ -2239,7 +2239,7 @@ FMT_CONSTEXPR bool do_check_format_string(basic_string_view<Char> s,
 }
 
 template <typename... Args, typename S,
-          typename std::enable_if<is_compile_string<S>::value, int>::type>
+          FMT_ENABLE_IF_T(is_compile_string<S>::value)>
 void check_format_string(S format_str) {
   typedef typename S::char_type char_t;
   FMT_CONSTEXPR_DECL bool invalid_format =