PYBIND11_NUMPY_DTYPE for union struct member - cannot compute offset of bit field

Hi,

I want to bind an array of union, say I have:

typedef union A_t {
  uint32_t full;
  struct {
     uint32_t x:16;
     uint32_t y:16;
  }f;
} A_t;

union B_t {
   struct {
       A_t  regs[10];
   } r ;
} B_t;

if I want to create a pybind11::array of that union I'd have to declare its DTYPE:

PYBIND11_NUMPY_DTYPE(A_t, full, f.x, f.y)

py::class_<B_t>(m, "B_t")
        .def(py::init<>())
        .def_property("regs", [](B_t &self) -> pybind11::array {
            auto dtype = py::dtype(pybind11::format_descriptor<A_t>::format());
            auto base = py::array(dtype, {10}, {sizeof(A_t)});
            return py::array(
                dtype, {10}, {sizeof(A_t)}, self.r.regs, base);
        }, [](B_t& ) {})

but I'm getting error:
error: cannot compute offset of bit-field 'x'.

Any suggestions on how to do that?

Reproduce the error with the shown A_t and B_t definitions and the PYBIND11_NUMPY_DTYPE declaration. Trace the dtype registration path that reports it cannot compute the offset of bit-field x, then determine whether union bit-fields can be supported or the limitation should be documented. Done means the behavior is resolved or clearly specified with a verified example.