}
    }

    private void validate20RawResources(
            ModelProblemCollector problems, List<Resource> resources, String prefix, ModelBuilderRequest request) {
        Severity errOn30 = getSeverity(request, ModelBuilderRequest.VALIDATION_LEVEL_MAVEN_3_0);

        for (Resource resource : resources) {
            validateStringNotEmpty(
                    prefix,
                    "directory",