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

I can show you how to detect a struct template:

template < class > struct check_template : std::false_type {};

// Specialize for template classes
template  class X, class... Args>
struct check_template< X > : std::true_type {};

You can then probably play around with declval, void_t, etc. to detect member templates.

In case you want to detect types vs. meta-types, i.e. templates like std::vector and not std::vector, you can do the following:

#include 

template  class>
constexpr bool is_template()
{
    return true;
}

template 
constexpr bool is_template()
{
    return false;
}

struct Foo{};

template
struct TemplateFoo{};

int main()
{
     std::cout << std::boolalpha;
     std::cout << is_template() << std::endl;
     std::cout << is_template() << std::endl;
}

Live on Coliru

Note that the solutions won't work if the meta-type has any non-type parameters, like

template struct X{};