diff --git a/core/modules/views/src/Plugin/views/filter/BooleanOperator.php b/core/modules/views/src/Plugin/views/filter/BooleanOperator.php
index 67c54c9..cdc2606 100644
--- a/core/modules/views/src/Plugin/views/filter/BooleanOperator.php
+++ b/core/modules/views/src/Plugin/views/filter/BooleanOperator.php
@@ -231,13 +231,13 @@ public function query() {
    * @param string $field
    *   The field name to add the where condition for.
    * @param string $query_operator
-   *   (optional) Either static::EQUAL or static::NOT_EQUAL. Defaults to
-   *   static::EQUAL.
+   *   (optional) Either self::EQUAL or self::NOT_EQUAL. Defaults to
+   *   self::EQUAL.
    */
   protected function queryOpBoolean($field, $query_operator = self::EQUAL) {
     if (empty($this->value)) {
       if ($this->accept_null) {
-        if ($query_operator == static::EQUAL) {
+        if ($query_operator === self::EQUAL) {
           $condition = (new Condition('OR'))
             ->condition($field, 0, $query_operator)
             ->isNull($field);
@@ -256,11 +256,11 @@ protected function queryOpBoolean($field, $query_operator = self::EQUAL) {
     else {
       if (!empty($this->definition['use_equal'])) {
         // Forces an '=' operator instead of a '<>' for performance reasons.
-        if ($query_operator == static::EQUAL) {
-          $this->query->addWhere($this->options['group'], $field, 1, static::EQUAL);
+        if ($query_operator === self::EQUAL) {
+          $this->query->addWhere($this->options['group'], $field, 1, self::EQUAL);
         }
         else {
-          $this->query->addWhere($this->options['group'], $field, 0, static::EQUAL);
+          $this->query->addWhere($this->options['group'], $field, 0, self::EQUAL);
         }
       }
       else {