diff --git a/core/modules/comment/src/Tests/Migrate/d6/MigrateCommentTest.php b/core/modules/comment/src/Tests/Migrate/d6/MigrateCommentTest.php
index 0458c54..ace556b 100644
--- a/core/modules/comment/src/Tests/Migrate/d6/MigrateCommentTest.php
+++ b/core/modules/comment/src/Tests/Migrate/d6/MigrateCommentTest.php
@@ -19,7 +19,15 @@ class MigrateCommentTest extends MigrateDrupal6TestBase {
 
   use CommentTestTrait;
 
-  static $modules = array('node', 'comment', 'text', 'filter');
+  static $modules = array(
+    'comment',
+    'filter',
+    'node',
+    // The RDF module is not actually used by the test, but enabling it will
+    // reproduce the fatal error addressed in issue #2558923.
+    'rdf',
+    'text',
+  );
 
   /**
    * {@inheritdoc}