return accessor.getBinaryCompatibility() == BinaryCompatibility.ACCESSORS_KEPT;
        });
        if (!keptAccessors.isEmpty()) {
            String formattedLeft = CollectionUtils.join("\n", keptAccessors.keySet());
            throw new RuntimeException("The following accessors were upgraded, but didn't match any removed/changed method:\n\n" + formattedLeft);
        }

        // Find accessors that were removed but shouldn't be

        Map<String, CtClass> oldInterfaces = collectImplementedInterfaces(oldClass)
        Map<String, CtClass> newInterfaces = collectImplementedInterfaces(newClass)

        newInterfaces.keySet().removeAll(oldInterfaces.keySet())

        if (newInterfaces.isEmpty()) {
            return null
        }

        List<String> changes = filterChangesToReport(newClass, newInterfaces)
        if (changes.isEmpty()) {