What is the test for making a declaration of rights after a finding that judgment should be against the actor in the lawsuit?

when a trial court reaches the conclusion, as it did in this case, that judgment should be against the actor in the lawsuit, it would be an illusory act to grant a further declaration of rights.... A declaration of rights, after such conclusion, would have served no useful purpose. And it is an accepted principle that no declaration should be made, unless it serve a useful, practical purpose, or when no beneficial result would follow.

United States v. Jones, 176 F.2d 278, 280 (9th Cir.1949). ⁶