This patch includes the fix for [LWG3940](https://cplusplus.github.io/LWG/issue3940) (`std::expected<void, E>::value()` also needs `E` to be copy constructible)
This patch includes the fix for [LWG3940](https://cplusplus.github.io/LWG/issue3940) (`std::expected<void, E>::value()` also needs `E` to be copy constructible)