code: public function visitExtensionType(ExtensionType $type)
      {
          $this->typeCheck->visitExtensionType(func_get_args());
  
          $extension = $this->extensionLoader->load($type->className()->string());
          $closure = $extension->generateTypeCheck($this, $type);
  
          $call = new Call($closure);
          $call->add($this->valueExpression());
  
          return $call;
      }
docs: @param ExtensionType $type
  
  @return Call