diff --git a/core/modules/views/src/Plugin/views/filter/FilterPluginBase.php b/core/modules/views/src/Plugin/views/filter/FilterPluginBase.php
index 3af0e9c..6f65f71 100644
--- a/core/modules/views/src/Plugin/views/filter/FilterPluginBase.php
+++ b/core/modules/views/src/Plugin/views/filter/FilterPluginBase.php
@@ -751,6 +751,7 @@ protected function buildGroupOptions() {
    * single filter.
    */
   public function groupForm(&$form, FormStateInterface $form_state) {
+    $groups = array();
     if (!empty($this->options['group_info']['optional']) && !$this->multipleExposedInput()) {
       $groups = array('All' => $this->t('- Any -'));
     }