title: Laravel class undefined after config:clear
body: <p><strong>App\Constant\ProductConstant.php</strong></p>
  
  <pre><code>&lt;?php
  
  namespace App\Constant;
  
  use App\Constant\BaseConstant;
  
  class ProductConstant extends BaseConstant {
  
      const TITLE = "title";
  }
  </code></pre>
  
  <p><strong>Product.php</strong></p>
  
  <pre><code>&lt;?php
  
  namespace App\Models;
  
  use App\Constant\ProductConstant;
  use Illuminate\Database\Eloquent\Model;
  
  class Product extends Model
  {
      protected $table = 'products';
  
      protected $fillable = [ProductConstant::TITLE, ProductConstant::IMAGE, ProductConstant::EXPIRY_DATE, ProductConstant::MAX_PARTICIPANTS, ProductConstant::TOTAL_PARTICIPANTS];
  </code></pre>
  
  <p><strong>Error</strong></p>
  
  <blockquote>
    <p>Undefined class constant 'App\Constant\ProductConstant::TITLE'</p>
  </blockquote>
  
  <p>After I've executed <code>php artisan config:clear</code>. May I know what's the reason? </p>