About setup and the order of calls between createComponentInstance

[YDKD]

Firstly, I' m studying vue3 and I don' t know that should my question be treated as an issues.

When I see the document about vue3, I found a problem what about Accessing Component Properties. I see it in the source code that When setup is executed, the component instance has been created.

The function createComponentInstance is called before the function setupComponent.

All the above are my personal understanding.