"Unresolvable dependency resolving" Error, Laravel Service Provider - php

Question

I'm trying my hand at building a custom Service Provider package, however I'm running into the following error. Does anyone have experience with this?
Unresolvable dependency resolving [Parameter #0 [ <required> $app ]] in class Illuminate\Support\ServiceProvider
Package Folder Structure:
[root]
....packages/
........mbarwick83/
............previewr/
................src/
....................PreviewrServiceProvider.php
....................Previewr.php
................composer.json
config/app.php:
Mbarwick83\Previewr\PreviewrServiceProvider::class
Service Provider:
<?php
namespace Mbarwick83\Previewr;
use Illuminate\Support\ServiceProvider;
class PreviewrServiceProvider extends ServiceProvider
{
/**
* Indicates if loading of the provider is deferred.
*
* #var bool
*/
protected $defer = false;
/**
* Perform post-registration booting of services.
*
* #return void
*/
public function boot()
{
//
}
/**
* Register any package services.
*
* #return void
*/
public function register()
{
$this->app->bind('Mbarwick83\Previewr\Previewr',function($app){
return new Previewr($app);
});
}
}
Previewr.php (class):
<?php
namespace Mbarwick83\Previewr;
class Previewr
{
/**
* Create a new Previewr Instance
*/
public function __construct()
{
//
}
/**
* Friendly welcome
*
* #param string $phrase Phrase to return
*
* #return string Returns the phrase passed in
*/
public function something($phrase)
{
return $phrase;
}
}
Controller/view:
use Mbarwick83\Previewr\PreviewrServiceProvider as Previewr;
public function index(Previewr $previewr)
{
echo $previewr->something('Hello, League!');
}
composer.json:
"autoload": {
"psr-4": {
"Mbarwick83\\Previewr\\": "packages/Mbarwick83/Previewr/src"
}
},

Answer 1

In your controller, are you sure you want to inject your service provider?
use Mbarwick83\Previewr\PreviewrServiceProvider as Previewr;
Chances are you want to use this instead:
use Mbarwick83\Previewr\Previewr;