Laravel Call to undefined function get()

I encountered a problem today, that is, executing the php artisan command on the command line keeps reporting an error. The error is as follows:

php artisan clear-compiled

[Symfony\Component\Debug\Exception\FatalErrorException]  
Call to undefined function get()   

I can't use composer update. Then I refer to an answer to fix it , and I can't check it. Finally, I thought of going to the storage/logs/laravel.log. Sure enough, the error is followed by a specific error message

[2016-11-18 09:14:40] local.ERROR: Symfony\Component\Debug\Exception\FatalThrowableError: Call to undefined function get() in test/routes/web.php:71

Once you find the exact location of the error, correct it.