I update laravel from v 6.0 to v6.2 and after the finish, I try php artisan route:list
This error
I had the same issue, i fixed it with the following solution:
This should fix the error.
Edit
The problem is, were updating the composer dependencies, but not the core application. But de composer dependencies expect you to update the core. They refer to files on the core application that not exists (because the application is not up-to-date).
See: How to update Laravel Application (not the composer dependencies)