If you write code manually, you can forget to update it in the future. For instance, a manual implementation of PartialEq might become stale if you add new fiel

If you write code manually, you can forget to update it in the future. For instance, a manual implementation of PartialEq might become stale if you add new fields in the future. If you could automatically generate the implementation, and simply guide the macro to use non-default behavior (e.g. skip a field, or use a more complicated trait bound on a generic type) then you can have the advantages of generated code without the disadvantages. Seems worth trying for, IMO.