gistfile1.cpp

#include <iostream>

template<typename D>
struct Hige
{
    void hige() { static_cast<D*>(this)->doit(); } // <- **
};

class Hoge
: Hige<Hoge>
{
    friend class Hige<Hoge>;
    void doit() { std::cout << "hoge\n"; }
public:
    void hige() { Hige<Hoge>::hige(); }
};

class Hage
: Hige<Hage>
{
    friend class Hige<Hage>;
    void doit() { std::cout << "hage\n"; }
public:
    void hige() { Hige<Hage>::hige(); }
};

class FooBar
: Hoge, Hage
{
public:
    void hoge() { Hoge::hige(); }
    void hage() { Hage::hige(); }
};


int main()
{
    FooBar fb;
    fb.hoge();
    fb.hage();
    return 0;
}