[boost] [type_traits] MSVC rejects typename -- why?

Subject: [boost] [type_traits] MSVC rejects typename -- why?
From: Lorenzo Caminiti (lorcaminiti_at_[hidden])
Date: 2011-03-23 19:58:47

Hello all,

The following code compiles on GCC (v3.4.3) but it does not on MSVC
(cl.exe v14):

#include <boost/type_traits.hpp>

template<typename T>
void f(T& x) {
    struct s {
        T g() {
            // GCC needs this typename but MSVC does not -- why??
            typename boost::remove_reference<T&>::type i = 0;
            return i;
        }
    };
    x = s().g();
}

int main() {
    int x;
    f(x);
    return 0;
}

MSVC does not accept the `typename` inside `s::g` because it says it's
not within a template (but I think it is within a template...). GCC
instead requires that `typename`.

Which compiler is right? (What does the standard say?) How do I
program this code so it works on all compilers?

Thank you very much.

--
Lorenzo