addViolation(problems, Severity.valueOf(problem.getSeverity().name()), problem.getMessage());
        }
    }

    // ----------------------------------------------------------------------
    // Field validation
    // ----------------------------------------------------------------------

    private static void addViolation(SettingsProblemCollector problems, Severity severity, String message) {

     * @param severity
     * @param version
     */
    public ModelProblemCollectorRequest(Severity severity, Version version) {
        this.severity = Objects.requireNonNull(severity, "severity cannot be null");
        this.version = Objects.requireNonNull(version, "version cannot be null");
    }

    public Severity getSeverity() {
        return severity;
    }

    public Version getVersion() {

    boolean hasFatalErrors();

    default void add(BuilderProblem.Severity severity, ModelProblem.Version version, String message) {
        add(severity, version, message, null, null);
    }

    default void add(
            BuilderProblem.Severity severity, ModelProblem.Version version, String message, InputLocation location) {
        add(severity, version, message, location, null);
    }

    default void add(

        assertEquals(Severity.ERROR, problem.getSeverity());

        problem = new DefaultProblem(null, Severity.FATAL, null, -1, -1, null);
        assertEquals(Severity.FATAL, problem.getSeverity());

        problem = new DefaultProblem(null, Severity.ERROR, null, -1, -1, null);
        assertEquals(Severity.ERROR, problem.getSeverity());

        this.message = message;
        this.severity = (severity != null) ? severity : Severity.ERROR;
        this.source = (source != null) ? source : "";
        this.lineNumber = lineNumber;
        this.columnNumber = columnNumber;
        this.exception = exception;
    }

    public String getSource() {
        return source;

    @Nonnull
    Settings getEffectiveSettings();

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link SettingsBuilderException}.
     *

    PersistedToolchains getEffectiveToolchains();

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link ToolchainsBuilderException}.
     *

 *
 */
public interface ProblemCollector {

    /**
     * Adds the specified problem.
     * Either message or exception is required
     *
     * @param severity The severity of the problem, must not be {@code null}.
     * @param message The detail message of the problem, may be {@code null}.
     * @param line The one-based index of the line containing the problem or {@code -1} if unknown.

    }

    @Test
    void testOneProblem() {
        ProblemCollector problemCollector = ProblemCollectorFactory.newInstance(null);
        problemCollector.add(Problem.Severity.ERROR, "MESSAGE", 3, 5, new Exception());
        ToolchainsBuildingException e = new ToolchainsBuildingException(problemCollector.getProblems());
        assertEquals(

    String getMessage();

    /**
     * Gets the severity level of this problem.
     *
     * @return the severity level of this problem, never {@code null}
     */
    @Nonnull
    Severity getSeverity();

    /**
     * The different severity levels for a problem, in decreasing order.
     *
     * @since 4.0.0
     */
    @Experimental
    enum Severity {
        FATAL, //
        ERROR, //