I have a simple code snippet below, which compiles using:

`g++-9 -std=c++2a -fconcepts`

This is trying to define a concept that requires the presence of a function. I would expect the output to be "yes" but it's not... Any idea why? Thanks.

```
#include <iostream>

template <typename T>
concept bool HasFunc1 = 
    requires(T) {
        { T::func1() } -> int;
    };

struct Test
{
    int func1()
    {
        return 5;
    }
};

int main()
{
    if constexpr (HasFunc1<Test>)
        std::cout << "yes\n";
}

```