Cannot convert argument - Template Error

I try to implement visitor pattern with templates.

My code is:

struct some_class
{
    char field1;
    bool field2;

    some_class()
        : field1('a')
        , field2(0)
    {
    }
};

struct unnamed_lambda
{
    template<typename T>
    T operator()(T x) const { return x + 1; }
};

struct unnamed_lambda2
{
    template<typename T>
    T operator()(T x) const { return x + 2; }
};


template<class processor>
void reflect(processor & p, some_class& sc)
{
    reflect(p, sc.field1, "field1");
    reflect(p, sc.field2, "field2");
}

template<class t>
void reflect(unnamed_lambda & p, t& val, string str)
{
    cout << val << endl;
}

void print_helper()
{
    unnamed_lambda lambda = unnamed_lambda{};
    some_class sc;

    reflect(lambda, sc);
}

template<class t>
void reflect2(unnamed_lambda2 & p, t& val, string str)
{
    cout << val + 1 << endl;
}

void print_helper2()
{
    unnamed_lambda2 lambda = unnamed_lambda2{};
    some_class sc;

    reflect(lambda, sc);
}

int main() 
{
    print_helper();
    print_helper2();

    return 0;
}

I want to have some class that defines traversal order of its fields. In my case, it is a void reflect(processor & p, some_class& sc) function. In addition, I want to have a set of actions on this class. In my case, It is print_helper and print_helper2.

In order to correlate the operation and the desired action, I create two dumb structure: unnamed_lambda and unnamed_lambda2. These structures do nothing. It is a workaround.

Why do this code smell so bad? There is a reason. The signature function void reflect(processor & p, some_class& sc) is fixed.

In other words, I can do everything except change the signature of this function and its implementation. More I can not change the some_class class.

I got confused. I'll be glad for any help on my question.