class SystemAdminMenuBlockAccessCheck

class SystemAdminMenuBlockAccessCheck implements AccessInterface {
    
    /**
     * Constructs a new SystemAdminMenuBlockAccessCheck.
     *
     * @param \Drupal\Core\Access\AccessManagerInterface $accessManager
     *   The access manager.
     * @param \Drupal\Core\Menu\MenuLinkTreeInterface $menuLinkTree
     *   The menu link tree service.
     * @param \Drupal\Core\Routing\AccessAwareRouter $router
     *   The router service.
     * @param \Drupal\Core\Menu\MenuLinkManagerInterface $menuLinkManager
     *   The menu link manager service.
     */
    public function __construct(AccessManagerInterface $accessManager, MenuLinkTreeInterface $menuLinkTree, AccessAwareRouter $router, MenuLinkManagerInterface $menuLinkManager) {
    }
    
    /**
     * Checks access.
     *
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The cron key.
     * @param \Drupal\Core\Session\AccountInterface $account
     *   The current user.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The access result.
     */
    public function access(RouteMatchInterface $route_match, AccountInterface $account) : AccessResultInterface {
        $parameters = $route_match->getParameters()
            ->all();
        $route = $route_match->getRouteObject();
        // Load links in the 'admin' menu matching this route. First, try to find
        // the menu link using all specified parameters.
        $links = $this->menuLinkManager
            ->loadLinksByRoute($route_match->getRouteName(), $parameters, 'admin');
        // If the menu link was not found, try finding it without the parameters
        // that match the route defaults. Depending on whether the parameter is
        // specified in the menu item with a value matching the default, or not
        // specified at all, will change how it is stored in the menu_tree table. In
        // both cases the route match parameters will always include the default
        // parameters. This fallback method of finding the menu item is needed so
        // that menu items will work in either case.
        // @todo Remove this fallback in https://drupal.org/i/3359511.
        if (empty($links)) {
            $parameters_without_defaults = array_filter($parameters, fn($key) => !$route->hasDefault($key) || $route->getDefault($key) !== $parameters[$key], ARRAY_FILTER_USE_KEY);
            $links = $this->menuLinkManager
                ->loadLinksByRoute($route_match->getRouteName(), $parameters_without_defaults, 'admin');
        }
        if (empty($links)) {
            // If we did not find a link then we have no opinion on access.
            return AccessResult::neutral();
        }
        return $this->hasAccessToChildMenuItems(reset($links), $account)
            ->cachePerPermissions();
    }
    
    /**
     * Check that the given route has access to child routes.
     *
     * @param \Drupal\Core\Menu\MenuLinkInterface $link
     *   The menu link.
     * @param \Drupal\Core\Session\AccountInterface $account
     *   The account.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The access result.
     */
    protected function hasAccessToChildMenuItems(MenuLinkInterface $link, AccountInterface $account) : AccessResultInterface {
        $parameters = new MenuTreeParameters();
        $parameters->setRoot($link->getPluginId())
            ->excludeRoot()
            ->setTopLevelOnly()
            ->onlyEnabledLinks();
        $route = $this->router
            ->getRouteCollection()
            ->get($link->getRouteName());
        if ($route && empty($route->getRequirement('_access_admin_menu_block_page')) && empty($route->getRequirement('_access_admin_overview_page'))) {
            return AccessResult::allowed();
        }
        foreach ($this->menuLinkTree
            ->load(NULL, $parameters) as $element) {
            if (!$this->accessManager
                ->checkNamedRoute($element->link
                ->getRouteName(), $element->link
                ->getRouteParameters(), $account)) {
                continue;
            }
            // If access is allowed to this element in the tree, check for access to
            // any of its own children.
            if ($this->hasAccessToChildMenuItems($element->link, $account)
                ->isAllowed()) {
                return AccessResult::allowed();
            }
        }
        return AccessResult::neutral();
    }

}