1. exceptions 2. garbage collection
Sometimes in slightly modified forms or names, and often with very well-articulated, technically competent justifications (as is the case here).
Just say no!
It's about borrowing a technique from languages that do have exceptions (and Rust's own panic unwinding) to implement Rust's existing error handling without making any changes to the language.
The post is light on how this would actually work, though. I think that re-using the name "stack unwinding" is a little misleading. The stack would only unwind if the error was bubbled up, which would only happen if the programmer coded it to. Indeed, the error could just get dropped anywhere up the stack, stopping it from unwinding further.
I think this would be tricky to implement, since the compiler would have to figure out which code actually is on the error path, and any given function could have multiple error paths (as many as one per each incoming error return, if they're all handled differently). It'd also make Result<T,E> even more special than it already is.
All that having been said, if you squint a bit, the end result does vaguely resemble Java's checked exceptions.
It is interesting to think why it is so for exceptions specifically. The discussion here offers some of the possible reasons, I think, including violent disagreement of what we all even mean by exceptions vs stack unwinding vs error propagation.
The article is about how we represent errors not their control flow (i.e., exceptions).
"Instead, when returning an error, rather than jumping to the return address, we look it up in the side table to find a corresponding error recovery address, and jump to that. Stack unwinding!
The bold claim is that unwinding is the optimal thing to do! .."
My opinion (which one need not approve of) is that it asymptotically approaches the language-level control flow constructs.
Adding ref to the SEH part of Microsoft C extensions https://learn.microsoft.com/en-us/cpp/cpp/structured-excepti...