Issue #2344831 by martin107, jhodgdon, tstoeckler, Mile23: Document behavior...

Issue #2344831 by martin107, jhodgdon, tstoeckler, Mile23: Document behavior of Drupal/Core/Database/Query/SelectInterface::__toString()

core/lib/Drupal/Core/Database/Query/SelectExtender.php

@@ -338,6 +338,9 @@ public function notExists(SelectInterface $select) {
     return $this;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function __toString() {
     return (string) $this->query;
   }

core/lib/Drupal/Core/Database/Query/SelectInterface.php

@@ -648,4 +648,12 @@ public function __clone();
    */
   public function forUpdate($set = TRUE);
 
+  /**
+   * Returns a string representation of how the query will be executed in SQL.
+   *
+   * @return string
+   *   The Select Query object expressed as a string.
+   */
+  public function __toString();
+
 }