code: protected function flashInput(Request $request = null)
  	{
  		if ($request === null) {
  			$request = $this->container
  				->resolve('Symfony\Component\HttpFoundation\RequestStack')
  				->getCurrentRequest();
  		}
  
  		$this->flash('_old_input', $request->request->all());
  	}
docs: Flash input to session.
  
  @param  \Symfony\Component\HttpFoundation\Request $request Optional
  
  @return void