Seems what we desire here is an "exact or alternative value" model instead of an "avoid overflow" model. This sounds interesting - can you showcase any related ruby behavior using this model?
I think an alternative can be *IfExact that returns a nullable value, if we do not need more information about the failure. Such a model is flattenable in the current programming model of Valhalla and can fulfill some of our needs. (I actually wonder if C2 can already inline and escape analysis in such a scenario) Unfortunately, before stack inlining drops, we are stuck with some tradeoffs - for example, current APIs still stick with Optional as it offers fluent code, which nullable types currently lack, even when we are promised a more flexible nullable type in the current roadmap of Valhalla.
