Laravel 5.2 验证错误未出现在Blade中

我想在用户输入错误时在查看页面中显示验证错误.当用户输入错误时，它不会在数据库中保存任何内容.但在用户查看页面中没有错误消息.如果有人发现错误，请帮我解决.

这是控制器:

public function saveUser(Request $request){
        $this->validate($request,[
            'name' => 'required|max:120',
            'email' => 'required|email|unique:users',
            'phone' => 'required|min:11|numeric',
            'course_id'=>'required'
            ]);

        $user = new User();
        $user->name=  $request->Input(['name']);
        $user->email=  $request->Input(['email']);
        $user->phone=  $request->Input(['phone']);
        $user->date = date('Y-m-d');
        $user->completed_status = '0';
        $user->course_id=$request->Input(['course_id']);
        $user->save();
       return redirect('success');         
    }

以下是路由:

Route::group(['middleware' => 'web'], function () {

    Route::get('/', function () {
        return view('index');
    })->name('main');

      Route::post('/saveUser',[
        'uses' => 'AppController@saveUser',
        'as'=>'saveUser',
        ]);
    });

以下是Blade 式服务器视图页面:

@extends('layouts.master')
@section('title')
Create User
@endsection
@section('content')
@include('partials.message-block')
        <div class="container" >

            <h3> Student Register </h3>

        {!! Form::open(array('route' => 'saveUser','class'=>'form-horizontal','method'=>'POST'))  !!}
      {!! Form::token(); !!}
      {!!   csrf_field() ; !!} 

        <div class="form-group">
          <label>Name</label>
          <input type="text" name="name" class="form-control" required placeholder="Name">
        </div>

        <div class="form-group">
          <label>Email</label>
          <input type="email" name="email" class="form-control" required placeholder="email">
        </div>

        <div class="form-group">
          <label>Phone Number</label>          
          <input type="text" name="phone" class="form-control" required placeholder="phone">
        </div>

        <div class="form-group">
            <label for="">Class</label>
            <select class="form-control input-sm" name="course_id" >
            @foreach($input as $row)
            <option value="{{$row->id}}">{{$row->name}}</option>
            @endforeach
            </select>
        </div>  

        <button type="submit" class="btn btn-default">Submit</button>
    {!! Form::close() !!}
        </div>

@endsection

And here is the error-message block:

@if(count($errors) > 0)
    <div class="row">
        <div class="col-md-4 col-md-offset-4 error">
            <ul>
                @foreach($errors->all() as $error)
                    <li>{{$error}}</li>
                @endforeach
            </ul>
        </div>
    </div>
@endif
@if(Session::has('message'))
<div class="row">
    <div class="col-md-4 col-md--offset-4 success">
        {{Session::get('message')}}
    </div>
</div>

@endif