namespace detail {
  template<typename impl_type, typename size_type, bool has_null_state> 
    struct basic_inplace;
  template<typename T = void> struct inplace_allocator;
  template<typename impl_type, typename storage_type> struct local_traits;
  template<typename impl_type, typename storage_type> struct static_traits;
}namespace impl_ptr_policy {
  template<size_t s, size_t a = std::size_t(-1)> struct storage;

  typedef detail::basic_inplace< impl_type, size_type, true > inplace;
  typedef detail::basic_inplace< impl_type, size_type, false > always_inplace;
}