With the release of Laravel 8, there has been a change to the routing syntax which might catch you by surprise, at least it did to me. It wasn't under the high or low impact changes so I skipped reading to the end and it came back to haunt me.

In a fresh laravel 8 install, I have this in my web.php file:

Route::get('/', 'HomeController@index');

and this in the index method of the HomeController.php

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        return view('welcome');
    }

This should be very familiar and we'd be expecting a view when we visit the / route. Rather what we see is an error page

You might start thinking you messed thing up, but no you didn't. Rather, in laravel 8 this syntax doesn't work by default. In the upgrade guide, it was mentioned but the likelihood of impact was optional 🤨. Though this was mentioned:

In most cases, this won't impact applications that are being upgraded because your RouteServiceProvider will still contain the $namespace property with its previous value. However, if you upgrade your application by creating a brand new Laravel project, you may encounter this as a breaking change.

The way to define your routes in laravel 8 is either

use App\Http\Controllers\HomeController;

// Using PHP callable syntax...
Route::get('/', [HomeController::class, 'index']);

OR

// Using string syntax...
Route::get('/', 'App\Http\Controllers\HomeController@index');

A resource route becomes

Route::resource('/', HomeController::class);

This means that in laravel 8, there is no automatic controller declaration prefixing by default.

If you want to stick to the old way, then you need to add a namespace property in the RouteServiceProvider.php (This property was present in previous versions) and activate in the routes method.

    /**
     * This namespace is applied to your controller routes.
     *
     * In addition, it is set as the URL generator's root namespace.
     *
     * @var string
     */
    protected $namespace = 'App\Http\Controllers';

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

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

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

To recap, in laravel 8 you can use the new syntax to define your routes or stick to the old way.