[Tyr42]

Sounds like checked and unchecked exceptions.

I mean, this could be a syntax wrapper for java checked exceptions right?

Those are isomorphic to Result<_, Err> in that you must handle or propagate the error. The syntax is different, sure.

[HendrikHensen]

Correct. Although the performance characteristics are different. An exception in Java generates a stack trace, which is relatively expensive. So not a great idea in un-exceptional code paths that need to perform well.

[vips7L]

Stack trace collection is optional. If you actually hit a performance problem on a checked exception path you just override the stack trace collection not to happen. I do this in most of my projects that use checked exceptions as domain errors. Only once you have to panic, i.e wrap in an unchecked exception, stack trace collection happens.