Possible bug? "nanobind::class_<> was invoked with extra arguments that could not be handled"

[dtromb]

I'm trying to bind base class [[A]] to module [[m1]], subclassed by implementation class [[B]] in module [[m2]]:

NB_MODULE(MODULE_NAME, m1) {
    m1.doc()               = "Example binding";
    m1.attr("__version__") = VERSION_INFO;
    nb::class_<[[A]]> c_[[A]]= nb::class_<[[A]]>(m1, "[[A]]");   
    
    nb::module_ m2 = m.def_submodule("sub", "Submodule of m1");
    
    // Above this line works fine!
    
    nb::class_<[[B]], [[A]]> [[B]] = nb::class_<[[B]], [[A]]>(m2, "[[B]]");
    
    // ^^ Fails with "extra arguments that could not be handled"!
}

Here is the relevent snip of nanobind, nb_class.h:453-465:

template <typename T, typename... Ts>
class class_ : public object {
public:
    NB_OBJECT_DEFAULT(class_, object, "type", PyType_Check);
    using Type = T;
    using Base  = typename detail::extract<T, detail::is_base,  Ts...>::type;
    using Alias = typename detail::extract<T, detail::is_alias, Ts...>::type;

    static_assert(sizeof(Alias) < (1 << 24), "Instance size is too big!");
    static_assert(alignof(Alias) < (1 << 8), "Instance alignment is too big!");
    static_assert(
        sizeof...(Ts) == !std::is_same_v<Base, T> + !std::is_same_v<Alias, T>,
        "nanobind::class_<> was invoked with extra arguments that could not be handled");

Any ideas?