private static void crawlContents(
            Model model,
            Shape startingShape,
            ShapeId trait,
            Shape currentTraitShape,
            Node leftValue,
            Node rightValue,
            List<ValidationEvent> events,
            String path
    ) {
        currentTraitShape.accept(new DiffCrawler(model, startingShape, trait, leftValue, rightValue, events, path));
    }
Traits in this list have special backward compatibility rules and can't be validated here.
smithy-diff/src/main/java/software/amazon/smithy/diff/evaluators/ModifiedTrait.java