How to make a variadic is_same?

Question

How can I make a class template that returns whether any of its variadic types are equal to the first type. I want to be able to do this:

is_same

        

Answer 1

In C++17 you have an even nicer solution, using template variables and fold expressions:

template
inline constexpr bool are_all_same = (std::is_same_v && ...);

And the usage is also simpler than all other examples:

are_all_same

No ::value, no parentheses!