Is it possible to check for existence of member templates just by an identifier?

Question

Can we detect member function template, variable template, class/struct/union template or alias templ

Answer 1

In C++14, you can use template variables to detect if a type is a specialization:

#include 

template
constexpr bool is_spec = false;

template class T, typename... U>
constexpr bool is_spec> = true;

struct S {};
template struct R {};

int main() {
    static_assert(not is_spec, "!");
    static_assert(is_spec>, "!");
}

Note that it won't work if non-type parameters are involved (as an example template struct R {};).