Laravel 5.1 to 5.2 composer update error - php

Question

Whenever I try to run composer update I now receive an error with a root cause of the following
Call to undefined method Illuminate\Bus\Dispatcher::mapUsing()
I can confirm Laravel 5.2 is properly installed, as are all other dependencies. This only happens when php artisan clear-compiled is run.
I've also updated my base controller based on a suggestion from a few hours ago in the Laracasts forum
use Illuminate\Foundation\Bus\DispatchesJobs;
use Illuminate\Routing\Controller as BaseController;
use Illuminate\Foundation\Validation\ValidatesRequests;
use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
abstract class Controller extends BaseController
{
use AuthorizesRequests, DispatchesJobs, ValidatesRequests;
}
But I still receive the error
UPDATE: This happens whenever the application is bootstrapped at all. My app won't even run now.
UPDATE 2, full stack trace:
PHP Fatal error: Call to undefined method Illuminate\Bus\Dispatcher::mapUsing() in /Users/Zara/Web/cafe/app/Providers/BusServiceProvider.php on line 16
PHP Stack trace:
PHP 1. {main}() /Users/Zara/Web/cafe/artisan:0
PHP 2. Illuminate\Foundation\Console\Kernel->handle() /Users/Zara/Web/cafe/artisan:36
PHP 3. Illuminate\Foundation\Console\Kernel->bootstrap() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:105
PHP 4. Illuminate\Foundation\Application->bootstrapWith() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:208
PHP 5. Illuminate\Foundation\Bootstrap\BootProviders->bootstrap() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:203
PHP 6. Illuminate\Foundation\Application->boot() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/BootProviders.php:17
PHP 7. array_walk() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:718
PHP 8. Illuminate\Foundation\Application->Illuminate\Foundation\{closure}() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:718
PHP 9. Illuminate\Foundation\Application->bootProvider() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:717
PHP 10. Illuminate\Container\Container->call() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Foundation/Application.php:734
PHP 11. call_user_func_array:{/Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Container/Container.php:507}() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Container/Container.php:507
PHP 12. Cafe\Providers\BusServiceProvider->boot() /Users/Zara/Web/cafe/vendor/laravel/framework/src/Illuminate/Container/Container.php:507
[Symfony\Component\Debug\Exception\FatalErrorException]
Call to undefined method Illuminate\Bus\Dispatcher::mapUsing()

Answer 1

From the Laravel 5.2 Upgrade Guide
Separate Commands & Handlers
The Laravel 5.2 command bus now only supports self-handling commands and no longer supports separate commands and handlers.
If you would like to continue using separate commands and handlers, you may install a Laravel Collective package which provides backwards-compatible support for this: https://github.com/LaravelCollective/bus
There is no longer support for non self handling commands which is what the mapper would be for; mapping commands to handlers.
Check Service Providers
Check any service providers you have registered to make sure they aren't calling that method on dispatcher. If still having that issue, you can try checking any package service providers to make sure they aren't calling that method.