Why can't operator () of stateless functor be static?

Question

Why is operator () of stateless functor not allowed to be static? Stateless lambda objects are convertible to pointers to free functions having the

Answer 1

I can't see any technical reason to forbid a static auto operator()( ... ). But it's a special case, so it would complicate the standard to add support for it. And such complication is not necessary, because it's very easy to emulate:

struct L
{
    static void func() {}

    void operator()() const { func(); }

    operator auto () const
    { 
        return &L::func;
    }
};

See Johannes' answer for some possibly useful extra info.