How to define a concept that checks for the size of a parameter pack?

[JUANDENT]

I want a concept that requires parameter packs to be of size > 0.
I wrote this:

template<typename...T>
concept NonEmpty = requires {sizeof...(T) > 0; };

This does no checking. For instance:

template<typename T1, typename ... T>  requires NonEmpty<T...>
struct Group<T1, T...> : Group<T...>  
///// etc 

What am I doing wrong?

[Peter87]

Doesn't this just check if sizeof...(T) > 0 is a valid expression?

[Peter87]

This seems to work:

template<typename...T>
concept NonEmpty = sizeof...(T) > 0;