Version

3.0.0-beta.10

Reproduction link

https://jsfiddle.net/4qxok5gh/3/

Steps to reproduce

• Run the reproduction

What is expected?

Reproduction should render:

23

What is actually happening?

A warning is printed in the console:

[Vue warn]: Property "a" was accessed during render but is not defined on instance.

I know that using v-for and v-if together is not recommended, but I could not find any rfc or issue in vue-next for a stricter enforcement of that best practice.