#include<type_traits>
 
template<class C, class T = int>
using EnableIf = typename std::enable_if<C::value, T>::type;
 
struct value1 { static const bool value = true; };
struct value2 { static const bool value = false; };
 
template<class T, EnableIf<std::is_integral<T>>...> // doesn't work
//template<class T, EnableIf<std::is_integral<T>> = 0> // works!
void fun(T){ };
template<class T, EnableIf<std::is_floating_point<T>>...> // doesn't work
//template<class T, EnableIf<std::is_floating_point<T>> = 0 > // works
void fun(T) { };
 
int main() {
  fun(1);
}
 

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