One could answer " when they are the same" but what if a question is answered by combination of more than one old post?
So, let's say a question ask how to show a statement C from a statement A but previously two questions were asked " show statement B from statement A" and " show statement C from statement B". How would one close then?
Honestly I feel it should be closed but its unclear on what basis it should be closed. It seems so the criteria for its closure is in some sense beyond the SE system.