basic_result(const basic_result &)

Copy constructor.

Requires: that value_type and error_type both implement a copy constructor.

Complexity: Same as for value_type’s and error_type’s copy constructors. Constexpr, triviality and noexcept of underlying operations is propagated.

Guarantees: If an exception is thrown during the operation, the object is left in a partially completed state, as per the normal rules for the same operation on a struct.