This means that the contract of EventuallySemigroup forbids using sumOption on Right. Hopefully this also means the plus operation on the right semigroup is already optimal (like adding to a set).

If we want to respect the fact that after every plus call on two Right elements we call mustConvert to decide wether the results should be converted to a Left then we need replace this line by ```val rs = new RightIterator(i).reduceOption(conditionallyConvert(Semigroup.plus(_, _)))```
and then sum the results accordingly.

I will do that change