BuilderProblem.Severity.WARNING));
                        return value;
                    }
                })
                .visit(toolchains);
    }

    /**
     * Collects the output of the toolchains builder.
     *
     */
    static class DefaultToolchainsBuilderResult implements ToolchainsBuilderResult {

    /**
     * Traverses this node and potentially its children using the specified visitor.
     *
     * @param visitor the visitor to call back, must not be {@code null}
     * @return {@code true} to visit siblings nodes of this node as well, {@code false} to skip siblings
     */
    boolean accept(@Nonnull NodeVisitor visitor);

    /**
     * Returns a new tree starting at this node, filtering the children.