C++0x: concept Convertible<T> issues

Hello!

I feed the following lines of code to the current GonceptG++ compiler
and was surprized that it didn't compile. It looks like
Convertible<int,T> doesn't cover implicit conversion which would allow
me using ints as parameters to a function that expects parameters of
type T.

----------8<----------
#include <iostream>
#include <concepts>

template<std::ArithmeticLike T>
T f(T a, T b) { return a + b; }

template<std::ArithmeticLike T> requires std::Convertible<int,T>
T g()
{
    const int i1 = 1;
    const int i2 = 2;
    return f<T>(i1,i2); // Error! No implicit conversion int-->T
    // Isn't this supposed to be covered by std::Convertible<int,T> ?
}

int main()
{
    using std::cout;
    using std::endl;
    double x = f<double>(1,2); // OK
    cout << x << endl;
}
----------8<----------

The error message I get is:

    convert.cpp: In function ?T g()?:
    convert.cpp:15: Fehler: keine passende Funktion f?r Aufruf
        von ?f(const int&, const int&)?

(Translation: "Error: no suitable function for call ?f(const int&,
const int&)?")

Since the standard draft (N2677) clearly distinguishes between
Convertible
and ExplicitlyConvertible I expected the Convertible<int,T> concept to
cover implicit conversion from int to T.

Is this behavior expected or is it possibly a compiler/library bug?

Cheers,
SG

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