As Gunnar Morling is saying, we cannot just change this behavior. The spec is clear on this. If anything it needs to be something which one can enable via a Hibernate Validator specific option.

I am also wondering what one really gains here. As nice as it sounds to: "a Set can be considered as special kind Map, where each element is mapped to itself" - it is still a bit of a stretch. I assume you you get your Path instance from a ConstraintViolation which already has a #getInvalidValue.