title: Yii2: Class 'Yii' not found
body: <p>I was learning Yii framework a few days ago. I facing with the error below:</p>
  
  <blockquote>
    <p>Fatal error: Class 'Yii' not found in C:\xampp\htdocs\LoginForm\views\user\views\default\register.php on line 17</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/DtnzR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DtnzR.png" alt="enter image description here"></a></p>