Re: Namespace vs. class ambiguity: three compilers - three different outcomes

Hello
 It is illegal to just flat-out declare a class and a namespace with identical names in the same scope
    namespace N {}
   class N {}; // <- Not allowed
 However, one can try to circumvent the direct restriction by means of using-directive or using-declaration
    #include <iostream>
    namespace N
   {
     void foo() { std::cout << "namespace" << std::endl; }
   }
    namespace X
   {
     struct N
     {
       static void foo() { std::cout << "class" << std::endl; }
     };
   }
    using X::N;
   // or
   // using namespace X;
    int main()
   {
     N::foo();
   }
 GCC is perfectly happy with either version of this code (both using- declaration and using-directive versions are OK). It simply resolves the call to the "namespace" version of `foo()`.
 Clang issues an error: it complains about the call being ambiguous. I.e. the error is issued at the point of the call.
 MSVC++ issues an error for `using X::N;` at the point of using- declaration: it basically says that `N` already exists in this scope. But if we switch to `using namespace X;` version, MSVC++ will exhibit Clang-like behavior: complain about ambiguity at the point of the call.
 So, who is right here?