For information, really (I tried Comeau, and it doesn't complain), here's another VC++ non-standardism:
Code:
// A.h
#include <vector>

class A
{
    typedef std::vector<int>::iterator iterator;

public:
    A() : v(10, 1) {}

private:
    iterator f();
    std::vector<int> v;
};

// A.cpp
#include "A.h"

A::iterator A::f()
{
    return v.begin();
}
VC++6.0 rejects this, saying that you can't access the private typedef A::iterator. Basically it seems to be failing to get the context of the (private) function before deciding whether private access is allowed. As I said, Comeau has no problem with it.