diff --git a/core/modules/comment/src/Plugin/views/row/Rss.php b/core/modules/comment/src/Plugin/views/row/Rss.php
index bbbce01..5f6f512 100644
--- a/core/modules/comment/src/Plugin/views/row/Rss.php
+++ b/core/modules/comment/src/Plugin/views/row/Rss.php
@@ -24,8 +24,15 @@
  */
 class Rss extends RssPluginBase {
 
-   var $base_table = 'comment';
-   var $base_field = 'cid';
+  /**
+   * {@inheritdoc}
+   */
+  protected $base_table = 'comment';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $base_field = 'cid';
 
   /**
    * {@inheritdoc}