Is this standard, or Visual C++ bug ?

Ok so consider this code :

namespace Bar
{
	template <class T2>
	T2 f()
	{
		return T2(0);
	}
}

template <class T>
void Foo(float y = Bar::f<float>())
{
}

int main()
{
	Foo<int>(); // C2783: 'T2 Bar::f(void)' : could not deduce template
argument for 'T2'
	return 0;
}

It does not compile with Visual C++ 2005 and 2008, but G++ has no
problem with it.
But now, if I remove the template from Foo, it works :

namespace Bar
{
	template <class T2>
	T2 f()
	{
		return T2(0);
	}
};


void Foo(float y = Bar::f<float>())
{
}

int main()
{
	Foo<int>(); // no problem
	return 0;
}

And if f is not in a namespace, it works too :

template <class T2>
T2 f()
{
	return T2(0);
}


template <class T>
void Foo(float y = f<float>())
{
}

int main()
{
	Foo<int>(); // no problem
	return 0;
}

Any idea ? Thank you.

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