Is there any use for named parameters into template template parameters

Question

If I need to define a template foo function with a template-template parameter, I usually do the following:

// Notice that the template paramete         


        

Answer 1

[basic.scope.temp]/p1:

The declarative region of the name of a template parameter of a template template-parameter is the smallest template-parameter-list in which the name was introduced.

_{(Now try saying that 10 times.)}

It can be used inside that list. For instance,

template < template<class T, T t> class TP > class foo {};
//                           ^  ^-----T's scope ends here
//                           |
//                           T can be used here

foo<std::integral_constant> bar;