How to store boost::hana::map inside a class?

I want to store boost::hana::map inside a class so that I can write code like this inside the class:

if constexpr (boost::hana::contains(map_, "name"_s)){
    std::cout << map_["name"_s] << std::endl;
}

But I am getting an error:

note: implicit use of 'this' pointer is only allowed within the evaluation of a call to a 'constexpr' member function

With this->map_:

note: use of 'this' pointer is only allowed within the evaluation of a call to a 'constexpr' member function

The most interesting thing is if I write like this:

if (boost::hana::contains(map_, "name"_s)){
    std::cout << map_["name"_s] << std::endl;
}

I get an error that there is no such field (it really may not exist, that's why there was an if constexpr).

And yet, it works like this(WHY?!):

auto map = map_;
if constexpr (boost::hana::contains(map, "name"_s)){
    std::cout << map["name"_s] << std::endl;
}

I absolutely don't understand how it works. How is boost::hana::map supposed to be used in this case?

Full example

Stupid workaround

Yes, using this here appears to be right out.

Since the information you are trying to access should be accessible at compile-time, one simple workaround would be to use the type of the entire expression.

void print_name()
{
    if constexpr (decltype(boost::hana::contains(map, "name"_s)){})
    {
        Print(map["name"_s]);
    }
}

Note that hana::contains returns an object derived from std::integral_constant so the contained value is static constexpr, and it implicitly converts to bool.