alt Hacker NewsWhy is it an extensibility hazard (assuming you mark the `pub enum Error` as non-exhaustive)?
I mean I don't see the difference between having the non-exhaustive enum at the top level vs in a subordinate 'kind'.
Why is it an extensibility hazard (assuming you mark the `pub enum Error` as non-exhaustive)?
I mean I don't see the difference between having the non-exhaustive enum at the top level vs in a subordinate 'kind'.
Take the example at https://docs.rs/thiserror/latest/thiserror/
- Struct variant fields are public, limiting how you evolve the fields and types
- Struct variants need non_exhaustive
- It shows using `from` on an error. What happens if you want to include more context? Or change your impl which can change the source error type
None of this is syntactically unique to errors. This becomes people's first thought of what to do and libraries like thiserror make it easy and showcase it in their docs.