Laravel Blade：访问包含文件中的变量返回undefined

Laravel 5.8
Voyager 1.2

I'm trying to access a variable in an included file from the parent blade view.

<!-- parent.blade.php -->
@include('vendor.voyager.test.child')
{{$i}} 

<!-- child.blade.php -->
@for($i=1; $i<5; $i++)
   {{$i}} 
@endfor

I'm expecting $i would be 4 in the parent.blade. Instead I got Undefined variable: i. Any help?