DeadCodeDetector: Report unused fields in contract address types

[jubnzv]

Closes #1099

[jubnzv]

Does this work for nested address types as well? I.e, something like this:

It could be implemented, but is it worth it? I think these cases are too rare to care about them, but it will complicate the checker.

[jjcnn]

Does this work for nested address types as well? I.e, something like this:

It could be implemented, but is it worth it? I think these cases are too rare to care about them, but it will complicate the checker.

I'm not sure how relevant it is. It sort of feels like a loose thread that we ought to tie up, but it might be better to ship what we have, and deal with nested address types later.

I do think we should open an issue on it, though, so that we don't forget.

[jubnzv]

I created the following issues about recursive fields: https://github.com/Zilliqa/scilla/issues/1182

[jjcnn]

Looks good.