Member function call in decltype

Question

The following code:

struct A
{
    int f(int);
    auto g(int x) -> decltype(f(x));
};

Fails to compile with the error:

erro         


        

Answer 1

Here are the magic words:

struct A
{
    int f(int);
    auto g(int x) -> decltype((((A*)0) ->* &A::f)(x)) ;
};

Edit I see from Mikael Persson's answer that this is how it's done in boost.