100   template<class U, class G _ENABLE_IF(
102     std::is_constructible_v<E, const G&> &&
103     !std::is_constructible_v<T, expected<U, G>&> &&
104     !std::is_constructible_v<T, expected<U, G>&&> &&
105     !std::is_constructible_v<T, const expected<U, G>&> &&
106     !std::is_constructible_v<T, const expected<U, G>&&> &&
107     !std::is_convertible_v<expected<U, G>&, T> &&
108     !std::is_convertible_v<expected<U, G>&&, T> &&
109     !std::is_convertible_v<const expected<U, G>&, T> &&
110     !std::is_convertible_v<const expected<U, G>&&, T> &&
112      !std::is_convertible_v<const G&, E>) /* non-explicit */
115   constexpr expected(const expected<U, G>& rhs) {  in expected()
120   template<class U, class G _ENABLE_IF(
122     std::is_constructible_v<E, const G&> &&
123     !std::is_constructible_v<T, expected<U, G>&> &&
124     !std::is_constructible_v<T, expected<U, G>&&> &&
125     !std::is_constructible_v<T, const expected<U, G>&> &&
126     !std::is_constructible_v<T, const expected<U, G>&&> &&
127     !std::is_convertible_v<expected<U, G>&, T> &&
128     !std::is_convertible_v<expected<U, G>&&, T> &&
129     !std::is_convertible_v<const expected<U, G>&, T> &&
130     !std::is_convertible_v<const expected<U, G>&&, T> &&
132      !std::is_convertible_v<const G&, E>) /* explicit */
134   constexpr explicit expected(const expected<U, G>& rhs) {  in expected()
139   template<class U, class G _ENABLE_IF(
141     std::is_constructible_v<E, const G&> &&
142     !std::is_constructible_v<T, expected<U, G>&> &&
143     !std::is_constructible_v<T, expected<U, G>&&> &&
144     !std::is_constructible_v<T, const expected<U, G>&> &&
145     !std::is_constructible_v<T, const expected<U, G>&&> &&
146     !std::is_convertible_v<expected<U, G>&, T> &&
147     !std::is_convertible_v<expected<U, G>&&, T> &&
148     !std::is_convertible_v<const expected<U, G>&, T> &&
149     !std::is_convertible_v<const expected<U, G>&&, T> &&
151      !std::is_convertible_v<const G&, E>) /* non-explicit */
154   constexpr expected(expected<U, G>&& rhs) {  in expected()
159   template<class U, class G _ENABLE_IF(
161     std::is_constructible_v<E, const G&> &&
162     !std::is_constructible_v<T, expected<U, G>&> &&
163     !std::is_constructible_v<T, expected<U, G>&&> &&
164     !std::is_constructible_v<T, const expected<U, G>&> &&
165     !std::is_constructible_v<T, const expected<U, G>&&> &&
166     !std::is_convertible_v<expected<U, G>&, T> &&
167     !std::is_convertible_v<expected<U, G>&&, T> &&
168     !std::is_convertible_v<const expected<U, G>&, T> &&
169     !std::is_convertible_v<const expected<U, G>&&, T> &&
171      !std::is_convertible_v<const G&, E>) /* explicit */
173   constexpr explicit expected(expected<U, G>&& rhs) {  in expected()
198   template<class G = E _ENABLE_IF(
199     std::is_constructible_v<E, const G&> &&
200     std::is_convertible_v<const G&, E> /* non-explicit */
203   constexpr expected(const unexpected<G>& e)  in expected()
206   template<class G = E _ENABLE_IF(
207     std::is_constructible_v<E, const G&> &&
208     !std::is_convertible_v<const G&, E> /* explicit */
210   constexpr explicit expected(const unexpected<G>& e)  in expected()
213   template<class G = E _ENABLE_IF(
214     std::is_constructible_v<E, G&&> &&
215     std::is_convertible_v<G&&, E> /* non-explicit */
218   constexpr expected(unexpected<G>&& e)  in expected()
221   template<class G = E _ENABLE_IF(
222     std::is_constructible_v<E, G&&> &&
223     !std::is_convertible_v<G&&, E> /* explicit */
225   constexpr explicit expected(unexpected<G>&& e)  in expected()
279   template<class G = E>
280   expected& operator=(const unexpected<G>& rhs) {
285   template<class G = E _ENABLE_IF(
286     std::is_nothrow_move_constructible_v<G> &&
287     std::is_move_assignable_v<G>
289   expected& operator=(unexpected<G>&& rhs) {
431   template<class U, class G _ENABLE_IF(
433     std::is_convertible_v<const G&, E> /* non-explicit */
436   constexpr expected(const expected<U, G>& rhs) {  in expected()
440   template<class U, class G _ENABLE_IF(
442     !std::is_convertible_v<const G&, E> /* explicit */
444   constexpr explicit expected(const expected<U, G>& rhs) {  in expected()
448   template<class U, class G _ENABLE_IF(
450     std::is_convertible_v<const G&&, E> /* non-explicit */
453   constexpr expected(expected<U, G>&& rhs) {  in expected()
457   template<class U, class G _ENABLE_IF(
459     !std::is_convertible_v<const G&&, E> /* explicit */
461   constexpr explicit expected(expected<U, G>&& rhs) {  in expected()
465   template<class G = E _ENABLE_IF(
466     std::is_constructible_v<E, const G&> &&
467     std::is_convertible_v<const G&, E> /* non-explicit */
470   constexpr expected(const unexpected<G>& e)  in expected()
473   template<class G = E _ENABLE_IF(
474     std::is_constructible_v<E, const G&> &&
475     !std::is_convertible_v<const G&, E> /* explicit */
477   constexpr explicit expected(const unexpected<G>& e)  in expected()
480   template<class G = E _ENABLE_IF(
481     std::is_constructible_v<E, G&&> &&
482     std::is_convertible_v<G&&, E> /* non-explicit */
485   constexpr expected(unexpected<G>&& e)  in expected()
488   template<class G = E _ENABLE_IF(
489     std::is_constructible_v<E, G&&> &&
490     !std::is_convertible_v<G&&, E> /* explicit */
492   constexpr explicit expected(unexpected<G>&& e)  in expected()
527   template<class G = E>
528   expected& operator=(const unexpected<G>& rhs) {
533   template<class G = E _ENABLE_IF(
534     std::is_nothrow_move_constructible_v<G> &&
535     std::is_move_assignable_v<G>
537   expected& operator=(unexpected<G>&& rhs) {