Is it valid C++ to do a template specialization of a function inside an inline namespace in the space outside the inline namespace?

For example, would this compile?

namespace A
{
    inline namespace A0
    {
        namespace B
        {
            template<typename T>
            T sum(T v1, T v2)
            {
                return v1 + v2;
            }
        }
    }
}

namespace A
{
    namespace B
    {
        template<>
        float sum<float>(float v1, float v2)
        {
            return v1 - v2; // Do something different
        }
    }
}

Currently, this code compiles with g++ 13.02, but not with MSVC 19.40 for c++17