bool Field_temporal::can_optimize_keypart_ref(const Item_bool_func *cond,
                                              const Item *value) const
{
  return true; // Field is of TIME_RESULT, which supersedes everything else.
}
bool Field_temporal::can_optimize_keypart_ref(const Item_bool_func *cond,
                                              const Item *value) const
{
  return true;  
}