Laravel 6.0 php artisan route:list returns “Target class [App\Http\Controllers\SessionsController] does not exist.”

I was upgrading from Laravel 7 to Laravel 8 (Laravel 8 is still a few days in development) and also had this issue.

The solution was to use a classname representation of the controller in the route:

So in web.php instead of

Route::get('registration/create', 'RegistrationController@create')

it is now:

Solution 1: Classname representation

use App\Http\Controllers\RegistrationController;

Route::get('/', [RegistrationController::class, 'create']);

Solution 2: String syntax

or as a string syntax (full namespaces controller name):

Route::get('/', 'App\Http\Controllers\RegistrationController@create');

Solution 3: Return to previous behaviour

As this should issue should only happen if you upgrade your application by creating a brand new laravel project you can also just add the default namespace to the RouteServiceProvider:

app/Providers/RouteServiceProvider.php

class RouteServiceProvider extends ServiceProvider
{
    /* ... */
     
    /** ADD THIS PROPERTY
     * If specified, this namespace is automatically applied to your controller routes.
     *
     * In addition, it is set as the URL generator's root namespace.
     *
     * @var string
     */
    protected $namespace = 'App\Http\Controllers';

    /**
     * Define your route model bindings, pattern filters, etc.
     *
     * @return void
     */
    public function boot()
    {
        $this->configureRateLimiting();

        $this->routes(function () {
            Route::middleware('web')
                ->namespace($this->namespace) // <-- ADD THIS
                ->group(base_path('routes/web.php'));

            Route::prefix('api')
                ->middleware('api')
                ->namespace($this->namespace) // <-- ADD THIS
                ->group(base_path('routes/api.php'));
        });
    }

    /* ... /*
}

See also https://laravel.com/docs/8.x/routing#basic-routing or https://laravel.com/docs/8.x/upgrade (search for "Routing").

For those who have similar issue with Illuminate\Contracts\Container\BindingResolutionException : Target class [<className>] does not exist. message, this also could be helpful:

composer dump-autoload

Run this command

  php artisan config:cache