Apple

This is almost FAQ #! for gcc 4.0 for C++ users and is covered in some detail in the gcc 4.0 Release Notes:

What you're looking for is this:

GCC 4.0 now implements "two-phase name lookup" correctly. This has the following consequences:

Within a template, you have to use the the typename keyword when a nested type depends on a template parameter. For example, if T is a template parameter, you have to write typename list<T>::iterator, not just list<T>::iterator. Without the typename, the compiler will parse this under the assumption that the name iterator doesn't refer to a type. (See section 14.6 of the C++ standard for more details.)
Names that do not depend on a template parameter are looked up at the point of template definition, not the point of instantiation. Within a template, for example, f(3) means whatever overload of f best matches an int argument at the point where the template is defined. If there is no appropriate version of f in scope then this is an error, even if such a function is declared later on.
If a class template inherits from another class template, then base class members won't be found unless they are qualified. (See section 14.6.2, paragraph 3, of the C++ standard.) For example:
template <typename T> struct Base {
void f();
};
template <typename T> struct Derived : public Base<T> {
void g() {
f(); // Error, name not found.
this->f(); // OK
Derived::f(); // OK
Base<T>::f(); // OK
}
};

References:
	>Problems since migrating to xcode 2 (From: Simon Harms <email@hidden>)