* <li>success with warnings - model field + non-error model problems
 * <li>error - no model, but diagnostics
 * <li>error - (partial) model and diagnostics
 * </ol>
 * Could encode these variants as subclasses, but kept in one for now
 *
 * @param <T> the model type
 */
public class Result<T> {

    /**
     * Success without warnings
     *
     * @param model
     */