[klodolph]

> The only problem with the Rust approach is that you have an extra if-statement on every single call to a fallible function, to unwrap the success/failure. If it used exceptions, the happy paths would (sometimes) be more optimized, if I understand correctly.

This is an implementation detail, and I’m not saying that lightly—I would not be surprised if future versions of Rust eliminated the conditional, because similar optimizations have been made in e.g. Haskell, and Rust has done some interesting work to optimize the run-time representation of enum types in the past to make them work the way you would expect the equivalent C types to work (e.g. Option<&X>).