dunno why DHoge::method() is accessible from outside...

private_method_can_call_from_global.cpp

#include <cstdio>

class Hoge
{
public:
  Hoge() {}
	virtual ~Hoge() {}

	virtual void method() {
		puts("hoge");
	}
};

class DHoge : public Hoge
{
public:
	DHoge() {}
	virtual ~DHoge() {}

private:
	void method() {
		puts("dhoge");
	}
};

int main(int argc, char const *argv[])
{
	Hoge* hoge = new DHoge();
	hoge->method();

	delete hoge;
	return 0;
}

This is a C++ spec
https://github.com/cplusplus/draft

11.5 Access to virtual functions [class.access.virt]
1 The access rules (Clause 11) for a virtual function are determined by its declaration and are not affected by the rules for a function that later overrides it.
2 Access is checked at the call point using the type of the expression used to denote the object for which the
member function is called (B* in the example above). The access of the member function in the class in which it was defined (D in the example above) is in general not known.