771 template <typename T> struct bit_reference {  struct
772    constexpr bit_reference(T& s, unsigned b) : storage(s), bit(b) {}  in bit_reference()  function
774    constexpr bit_reference& operator=(const bit_reference& other) { return *this = (bool)other; }
776    constexpr bit_reference& operator=(bool val)
783    constexpr bit_reference& operator^=(bool val)
789    constexpr bit_reference& operator|=(bool val)
795    constexpr bit_reference& operator&=(bool val)
810    template <typename other_T> constexpr void swap(bit_reference<other_T> other)  in swap()  argument
841       const bitfield_iterator<ncT, bit_reference<ncT>, bit_reference<ncT>*>& x)  in bitfield_iterator()  argument
860    constexpr reference operator*() const { return bit_reference<T>(*bf, index); }
944    using reference = bit_reference<data_type>;
946    using pointer = bit_reference<data_type>*;
949       bitfield_iterator<data_type, bit_reference<data_type>, bit_reference<data_type>*>;