Function check_enabled_formatter

test/format-test.cc:2346–2350

}

template <typename Char, typename T> auto check_enabled_formatter() -> bool {
  static_assert(std::is_default_constructible<fmt::formatter<T, Char>>::value,
                "");
  return true;
}

template <typename Char, typename... T> void check_enabled_formatters() {
  auto dummy = {check_enabled_formatter<Char, T>()...};