30 template<class To, class From>
31 concept bit_cast_is_valid = requires(From from) {
38     struct From { char a; char b; };  argument
39     static_assert(!bit_cast_is_valid<To, From>);
40     static_assert(!bit_cast_is_valid<From&, From>);
46     struct From { char a; };  struct
47     static_assert(!bit_cast_is_valid<To, From>);
53     struct From { char a; From(From const&); };  argument
54     static_assert(!bit_cast_is_valid<To, From>);
59     struct From { char a; char b; };  argument
60     static_assert(!bit_cast_is_valid<char[2], From>);
61     static_assert(!bit_cast_is_valid<int(), From>);