Version

3.0.0

Reproduction link

https://jsfiddle.net/7bahj9su/1/

Steps to reproduce

1. Watch an array
2. Push to the array

What is expected?

Watch should trigger after push.

What is actually happening?

Nothing.

It is working in Vue 2: https://jsfiddle.net/7bahj9su/

I think this is a duplicate of #2116

Duplicate of #2116

I think it is different with #2116 . Use { flush: 'post' } in Composition API could solve it. It might be caused by the broken change of 3.0.0-rc.13.