Example detailing Laravel ServiceProvider registration error. Refer to this issue: https://github.com/laravel/framework/issues/2760

app.php

<?php 

return array(
  
  /* truncated */

  /* this app.php config file will work because 'bar.dependency' has been registered on the container before 
   * BrokenFooServiceProvider so that when 'bar.dependency' is being called for, it already exists.
   */

	'providers' => array(

		'BarDependencyServiceProvider',
		'BrokenFooServiceProvider',

	),

);

badapp.php

<?php 

return array(
  
  /* truncated */

  /* this app.php config file will break and throw the ReflectionException because BarDependencySerivceProvider has not 
   * has not registered the 'bar.dependency' on the container yet.
   */

	'providers' => array(

		'BrokenFooServiceProvider',
		'BarDependencyServiceProvider',
	),

);

BarDependencyServiceProvider.php

<?php 

use Illuminate\Support\ServiceProvider;

class BarDependencyServiceProvider extends ServiceProvider {

	public $defer = true;

	public function register()
	{
		$this->app->bindShared('bar.dependency', function($app) use ($required)
		{
			return new BarDependency;
		});
	}

  public function provides()
  {
    return array('bar.dependency');
  }

}

BrokenFooServiceProvider.php

<?php 

use Illuminate\Support\ServiceProvider;

class BrokenFooServiceProvider extends ServiceProvider {

	public $defer = true;


  /**
   * this function will NOT work and throw following exception:
   * {"error":{"type":"ReflectionException","message":"Class bar.dependency does not exist",
   *  "file":"path\\to\\vendor\\laravel\\framework\\src\\Illuminate\\Container\\Container.php","line":485}}
   * 
   */
	public function register()
	{
	  $bar = $this->registerBarClass();
	  
		$this->app->bindShared('foo', function($app) use ($bar)
		{
			return new FooClass($bar);
		});
	}

	protected function registerBarClass()
	{
	  $dependency = $this->app['bar.dependency'];
	  
	  return new BarClass($dependency);
	}

  public function provides()
  {
    return array('foo');
  }

}

WorkingFooServiceProvider.php

<?php 

use Illuminate\Support\ServiceProvider;

class WorkingFooServiceProvider extends ServiceProvider {

	public $defer = true;


  /**
   * this file will work regardless of how the ServiceProviders are ordered within the app.php config file. 
   * This is because the registration of BarClass which depends upon 'bar.dependency' is taking place within the closure
   * passed to $this->app->bindShared()
   */
	public function register()
	{
	  $me = $this;
	  
		$this->app->bindShared('foo', function($app) use ($me)
		{
		  $bar = $me->registerBarClass();
		  
			return new FooClass($bar);
		});
	}

	public function registerBarClass()
	{
	  $dependency = $this->app['bar.dependency'];
	  
	  return new BarClass($dependency);
	}

  public function provides()
  {
    return array('foo');
  }

}