Comment by blixt
Yeah maybe they're overrated, but they seem like the agreed-upon set of types to avoid null and to standardize error handling (with some support for nice sugars like Rust's ? operator).
I quite often see devs introducing them in other languages like TypeScript, but it just doesn't work as well when it's introduced in userland (usually you just end up with a small island of the codebase following this standard).
Typescript has another way of dealing with null/undefined: it's in the type definition, and you can't use a value that's potentially null/undefined. Using Optional<T> in Typescript is, IMO, weird. Typescript also has exceptions...
I think they only work if the language is built around it. In Rust, it works, because you just can't deref an Optional type without matching it, and the matching mechanism is much more general than that. But in other languages, it just becomes a wart.
As I said, some kind of type annotation would be most go-like, e.g.
You would only be allowed to touch *ptr inside a if ptr != nil { ... }. There's a linter from uber (nilaway) that works like that, except for the type annotation. That proposal would break existing code, so perhaps something an explicit marker for non-nil pointers is needed instead (but that's not very ergonomic, alas).