Is g++ misbehaving with function template overloading?

Question

I took the following example from http://en.cppreference.com/w/cpp/language/function_template#Function_template_overloading and clang (3.4) seems to be handling it just fine, while g++ (4.8.3) gives an 'ambiguous overload' error:

struct A {};
template<class T> struct B {
  template<class R> void operator*(R&){ cout << "1" << endl; }             // #1
};
template<class T, class R> void operator*(T&, R&) { cout << "2" << endl;}  // #2
int main() {
  A a;
  B<A> b;
  b * a; //prints 1
}

clang correctly prints 1 (as expected according to cppreference), while g++ gives this error:

test_templates.cpp: In function ‘int main()’:
test_templates.cpp:13:5: error: ambiguous overload for ‘operator*’ (operand types are ‘B<A>’ and ‘A’)
   b * a; //prints 1
     ^
test_templates.cpp:13:5: note: candidates are:
test_templates.cpp:7:26: note: void B<T>::operator*(R&) [with R = A; T = A]
   template<class R> void operator*(R&){ cout << "1" << endl; }            // #1
                          ^
test_templates.cpp:9:33: note: void operator*(T&, R&) [with T = B<A>; R = A]
 template<class T, class R> void operator*(T&, R&) { cout << "2" << endl;}  // #2

Is g++ actually misbehaving here?

Answer 1

This example is taken from the standard (this is the draft for c++11).

14.5.6.2 Partial ordering of function templates paragraph 3 example:

struct A { };
template<class T> struct B {
  template<class R> int operator*(R&); // #1
};
template<class T, class R> int operator*(T&, R&); // #2
// The declaration of B::operator* is transformed into the equivalent of
// template<class R> int operator*(B<A>&, R&); // #1a
int main() {
  A a;
  B<A> b;
  b * a; // calls #1a
}

So, the standard itself pretty much say this is legal code. I could copy-paste rules, but one might as well click link and jump to the relevant place. My point is only to prove this is a proper compilable code as defined by the standard.

For what it's worth on my debian clang 3.5.0 compiled it right away, clang 3.4.2 had to be executed with -std=c++11, g++ 4.9.1 reported ambiguity in all cases (I even tried 1y).

I am puzzled by clang behaviour, though. I thought it might have been ambiguous in earlier versions of c++, the rule to disambiguate was added as a part of c++11 and g++ didn't keep up. But clang 3.5 compiles it even with -std=c++98.