diff --git a/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php b/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php
index 53e37e3..b2f125e 100644
--- a/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php
+++ b/core/modules/system/src/Plugin/migrate/destination/d7/ThemeSettings.php
@@ -88,7 +88,7 @@ public function getIds() {
    */
   public function fields(MigrationInterface $migration = NULL) {
     // Theme settings vary by theme, so no specific fields are defined.
-    return array();
+    return [];
   }
 
 }