std::assignable_from - [concept.assignable], concept assignable_from

       Generated automatically by Doxygen for libstdc++ from the source code.

                                                    libstdc++                         std::assignable_from(3cxx)

       template<typename _Lhs, typename _Rhs>
       concept std::assignable_from =  is_lvalue_reference_v<_Lhs>
             && common_reference_with<__detail::__cref<_Lhs>, __detail::__cref<_Rhs>>
             && requires(_Lhs __lhs, _Rhs&& __rhs) {
               { __lhs = static_cast<_Rhs&&>(__rhs) } -> same_as<_Lhs>;
             }

       [concept.assignable], concept assignable_from

       std::assignable_from - [concept.assignable], concept assignable_from

       #include <concepts>