Fixes #3311.

framework/CHANGELOG.md

@@ -22,6 +22,7 @@ Yii Framework 2 Change Log
 - Bug #3216: Fixed the bug that `yii.activeForm.destroy()` did not remove `submit` event handlers (qiangxue)
 - Bug #3236: Return value for DateTime->format('U') casted to double to allow correct date formatting (pgaultier)
 - Bug #3268: Fixed the bug that the schema name in a table name was not respected by `yii\db\mysql\Schema` (terazoid, qiangxue)
+- Bug #3311: Fixed the bug that `yii\di\Container::has()` did not return correct value (mgrechanik, qiangxue)
 - Enh #2264: `CookieCollection::has()` will return false for expired or removed cookies (qiangxue)
 - Enh #2837: Error page now shows arguments in stack trace method calls (samdark)
 - Enh #2906: Added support for using conditional comments for js and css files registered through asset bundles and Html helper (exromany, qiangxue)

framework/di/Container.php

@@ -277,7 +277,7 @@ class Container extends Component
      */
     public function has($class)
     {
-        return isset($this->_singletons[$class]);
+        return isset($this->_definitions[$class]);
     }
 
     /**