Why is it necessary to use @+id instead of @id?

Question

I know the difference between @+id and @id (see this accepted answer). However, I always get the feeling that I'm doing the job of the AAPT compiler when I write the '+' in @+id.

Is there a reason the resource compiler cannot infer by itself if an identifier must be created or just reused? An underlying hashtable structure would do the job: every resource with the same id go into the same bucket, and if the key does not exist, just create it.

Answer 1

Probably the compiler would not be able to differentiate between a 'right' and a 'wrong' id. If it finds a new id (i.e. one that is not in the underlying hashtable), it would always assume it to be a right, new id. It would not be able to differentiate between an actual new id and a mistyped id.