Added missing using statement in Gii.

extensions/gii/generators/crud/default/search.php

@@ -24,6 +24,7 @@ echo "<?php\n";
 
 namespace <?= StringHelper::dirname(ltrim($generator->searchModelClass, '\\')) ?>;
 
+use Yii;
 use yii\base\Model;
 use yii\data\ActiveDataProvider;
 use <?= ltrim($generator->modelClass, '\\') . (isset($modelAlias) ? " as $modelAlias" : "") ?>;

extensions/gii/generators/model/default/model.php

@@ -17,6 +17,8 @@ echo "<?php\n";
 
 namespace <?= $generator->ns ?>;
 
+use Yii;
+
 /**
  * This is the model class for table "<?= $tableName ?>".
  *