If you are not passing the request data with the $data array, i.e. if you are performing the IP request in Registrar.php, then you may have to add the following line

use Illuminate\Http\Request

or

use Request

I use it my code:

<?php namespace App\Services;

use App\User;
use Illuminate\Http\Request;
use Validator;
use Illuminate\Contracts\Auth\Registrar as RegistrarContract;

class Registrar implements RegistrarContract {

	/**
	 * Get a validator for an incoming registration request.
	 *
	 * @param  array  $data
	 * @return \Illuminate\Contracts\Validation\Validator
	 */
	public function validator(array $data)
	{
		return Validator::make($data, [
			'name' => 'required|max:255',
			'email' => 'required|email|max:255|unique:users',
			'password' => 'required|confirmed|min:6',
		]);
	}

	/**
	 * Create a new user instance after a valid registration.
	 *
	 * @param  array  $data
	 * @return User
	 */
	public function create(array $data)
	{
		return User::create([
                       'name' => $data['name'],
			'ip' => Request::ip(),
			'email' => $data['email'],
			'password' => bcrypt($data['password']),
		]);
	}

}

but it do not work and error is:

Non-static method Illuminate\Http\Request::ip() should not be called statically, assuming $this from incompatible context

@snapey thank you it work but otherwise you say i must change create method in compiled.php really thank you ;)

@snapey

Isn't that the same as using

use Request;

as I suggested above? You simply inject the Request class directly into the function...