Please describe what the rule should do:

This rule warns never use v-if on the same element as v-for.

Style guide:
https://vuejs.org/v2/style-guide/#Avoid-v-if-with-v-for-essential

What category of rule is this? (place an "X" next to just one item)

[X] Enforces code style
[ ] Warns about a potential error
[ ] Suggests an alternate way of doing something
[ ] Other (please specify:)

Provide 2-3 code examples that this rule will warn about:

<ul>
  <li
    v-for="user in users"
    v-if="user.isActive"
    :key="user.id"
  >
    {{ user.name }}
  </li>
</ul>

Why should this rule be included?

This rule is stated in the Style guide as ESSENTIAL.
It is similar to vue/no-confusing-v-for-v-if, but the content of code examples is not warned.

I confirmed issues, but I could not find duplicate rules.
I'm sorry if it was duplicated.