<?php namespace Pingpong\Whoops;

use Illuminate\Support\ServiceProvider;

class ServiceProvider extends ServiceProvider {

    /**
     * Indicates if loading of the provider is deferred.
     *
     * @var boolean
     */
    protected $defer = false;

    /**
     * Register the service provider.
     */
    public function register()
    {
        $this->app->singleton(
            'Illuminate\Contracts\Debug\ExceptionHandler',
            'Pingpong\Whoops\WhoopsHandler'
        );
    }

    /**
     * Get the services provided by the provider.
     *
     * @return array
     */
    public function provides()
    {
        return ['Illuminate\Contracts\Debug\ExceptionHandler'];
    }

}

<?php namespace Pingpong\Whoops;

use Illuminate\Support\ServiceProvider;

class WhoopsServiceProvider extends ServiceProvider {

    /**
     * Indicates if loading of the provider is deferred.
     *
     * @var boolean
     */
    protected $defer = false;

    /**
     * Register the service provider.
     */
    public function register()
    {
        $this->app->singleton(
            'Illuminate\Contracts\Debug\ExceptionHandler',
            'Pingpong\Whoops\WhoopsHandler'
        );
    }

    /**
     * Get the services provided by the provider.
     *
     * @return array
     */
    public function provides()
    {
        return ['Illuminate\Contracts\Debug\ExceptionHandler'];
    }

}

Fix class name according to filename.
Fix class name according to filename.