The cb of the watch is not called when change by array mutation methods
Version
3.0.7
Reproduction link
https://codesandbox.io/s/hopeful-smoke-01r6s?file=/src/App.vue
Steps to reproduce
Just click the item.
What is expected?
In vue2, the cb of the watch will be triggered correctly.
The cb of watch will be triggered like vue2.
What is actually happening?
The view has been updated, but the cb of watch is not called.