Laravel 5.6 - Seeder Class not found

I'm trying to populate a Laravel 5.6 project DB - following the offial docs - without success. php artisan db:seed throws this exception:

Symfony\Component\Debug\Exception\FatalThrowableError : Class 'App\Item' not found

at /Applications/MAMP/htdocs/greylab/inventario/greylab_inventario/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php:217

Exception trace:

1 Illuminate\Database\Eloquent\FactoryBuilder::make([]) /Applications/MAMP/htdocs/greylab/inventario/greylab_inventario/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php:167

2 Illuminate\Database\Eloquent\FactoryBuilder::create() /Applications/MAMP/htdocs/greylab/inventario/greylab_inventario/database/seeds/ItemTableSeeder.php:14

I already tried most of the common suggestions provided from the community, like this one, as well as:

• Trying with composer self-update + composer dump-autoload;
• On my composer.json the autoload property is set as is:

"autoload": { "classmap": [ "database/seeds", "database/factories" ], "psr-4": { "App\\": "app/" } },

(Tried to put classmap in autoload-dev too).

Here's the situation:

ItemFactory.php

<?php

use Faker\Generator as Faker;

// Definizione dati test
$factory->define(App\Item::class, function (Faker $faker) {
    return [ ...]
}

ItemTableSeeder.php

<?php

use Illuminate\Database\Seeder;

class ItemTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        factory(App\Item::class, 25)->create();
    }
}

DatabaseSeeder.php

<?php

use Illuminate\Database\Seeder;

class DatabaseSeeder extends Seeder
{
    /**
     * Seed the application's database.
     *
     * @return void
     */
    public function run()
    {
        $this->call(ItemTableSeeder::class);
    }
}

• At last, I tried to put dependencies directly in sources too:

use App\Item; use Illuminate\Database\Seeder;

by removing the App\ prefix and leave only Item::class in the argument:

factory(Item::class, 25)->create();

All these tries didn't helped, so I'm actually stuck. If anyone could show me the way, it should be really appreciated.

Thanks in advance to all.

via Chebli Mohamed