Cleanup

Look over the current change (or the whole codebase if there is no current change) and look for:

• Any transformations or indexes that are redundant with data structures or relationships already known earlier in the whole-program data flow.
• Any backwards-compatibility shims, unnecessary defensive code, or unnecessary deduplication.
• For any deduplication added in this change, ask yourself: could these objects have arrived here inherently deduplicated?

Print out your findings, if any. Then, fix any findings you found.

After fixing your findings, look over the code again: now that we have done that cleanup, are there any other cleanups available? Print out your new findings. Then fix them.