The type derived from `_ERROR_` should not be considered as `__msuccess`

[yanminhui]

stdexec/include/stdexec/__detail/__meta.hpp

Lines 172 to 178 in 124be24

	template <class>
	extern __msuccess __ok_v;
	template <class _What, class... _With>
	extern _ERROR_<_What, _With...> __ok_v<__mexception<_What, _With...>>;

Use overload instead of specialization:

consteval __msuccess __get_ok_type(...);

template <class What, class... With>
consteval _ERROR_<What, With...> __get_ok_type(const _ERROR_<What, With...>*);

template <class _Ty>
extern decltype(__get_ok_type((_Ty*)nullptr)) __ok_v; // Use overload instead of specialization

Use case: https://godbolt.org/z/P1eGccsEY