Need some clarification

I could see the following in TODO list
but I am not clear what is expected out of this.
Can anyone explain this?

1. *Allow VIEW/RULE recompilation when the underlying tables change *

* Another issue is whether underlying table changes should be
reflected in the view,
e.g. should SELECT * show additional columns if they are added after
the view is created. *

Dropping/altering column is not allowed in the above mentioned scenario.
Only it fails for (select *)
What are the other cases in which it fails?

2. *Invalidate prepared queries, like INSERT, when the table definition
is altered

*Invalidation means recompilation or deletion of the prepared stmt here.*
*Both the items look similar. i.e) needs recompilation of the query
after altering the table.
It is right?*
*