升级到更高版本时，Laravel会出错

I upgraded my laravel application from 5.2 to 5.5 I am getting this error:

"Trait 'Illuminate\Foundation\Auth\AuthenticatesAndRegistersUsers' not found"

I am using php 7.1.2 I am getting this error.

My composer json file is:

"require": {
    "php": ">=7.1.2",
    "laravel/framework": "5.6.*",
    "doctrine/dbal": "^2.5",
    "laravel/tinker": "^1.0",
    "maatwebsite/excel": "~2.1.0"
},

I am using this inside authcontroller.php:

use Illuminate\Foundation\Auth\RegistersUsers;
use Illuminate\Foundation\Auth\AuthenticatesUsers;

But I am getting error I used this answer but it is not clear.

Suggested answer

I am using these traits in auth controller:

use App\User;
use Validator;
use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\ThrottlesLogins;
use Illuminate\Foundation\Auth\AuthenticatesAndRegistersUsers;
use Session;
use Illuminate\Support\Facades\Auth;
use App\UserActivity1;
use Illuminate\Foundation\Auth\RegistersUsers;
use Illuminate\Foundation\Auth\AuthenticatesUsers;