Laravel 5.4 Artisan Migrate fails with Call to undefined method dispatch()

Delete all files from /bootstrap/cache/ and run these commands

php artisan cache:clear
php artisan view:clear

It should fix your problem

I think your composer is not updated. Try uninstalling the composer and then re-installing it. Or try with updating the composer.phar. Probably there is version issue between the laravel you are using.