更新

app/Admin/Controllers/UserController.php

@@ -118,9 +118,9 @@ class UserController extends AdminController
         $form->text('city','所在城市')->default("成都市");
         $form->radio('online','在线状态')->options([0=>'离线',1=>'在线'])->default(1);
         $form->switch('status','状态')->default(1);
-        $form->saving(function ($res){
+        $form->saving(function ($res)use ($form){
             if(User::query()->where('mobile',$res->mobile)->first()){
-                return $res->error("手机号已存在");
+                return $form->response()->error('手机号已存在');
             }
         });
         return $form;