php artisan blueprint:erase -> Error -> Class 'Doctrine\DBAL\Driver\PDOMySql\Driver' not found

 The doctrine/dbal dependency needs to be added to your composer.json

composer require doctrine/dbal

For more information check laravel #Modifying Columns

OR 

You have to downgrade the current version, this is what worked for me:

edit your composer.json file :

composer require doctrine/dbal:2.*

and execute the command :

composer update