https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114400
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oops, that was meant to be:
#ifdef __cpp_lib_type_identity // C++ >= 20
/** * Identity metafunction.
* @since C++20
* @{
*/
template<typename _Tp>
struct type_identity { using type = _Tp; };
template<typename _Tp>
using type_identity_t = typename type_identity<_Tp>::type;
/// @}
template<typename _Tp>
using __type_identity = type_identity<_Tp>;
template<typename _Tp>
using __type_identity_t = type_identity_t<_Tp>;
#else
/// @cond undocumented
template <typename _Type>
using __type_identity
{ using type = _Type; };
template<typename _Tp>
using __type_identity_t = typename __type_identity<_Tp>::type;
#endif
But that messes up the @cond / @endcond nesting. Anyway, something like that.
