I think the nonlocal part is the scary part: it becomes very scary to figure out which parts of the code can fail and how, especially when failures can come fro

I think the nonlocal part is the scary part: it becomes very scary to figure out which parts of the code can fail and how, especially when failures can come from an arbitrarily deep call stack. Maybe checked exceptions could be more useful to explicitly annotate allowed failures, but at the same time we all know how that's going in Java world.