[epage]

I think we should provide the building blocks (display, etc like derive_more) rather than a specialized version one for errors (thiserror).

I also feel thiserror encourages a public error enum which to me is an anti-pattern as they are usually tied to your implementation and hard to add context, especially if you have a variants for other error types.

[the8472]

I don't quite understand the issue about public error enums? Distinguishing variants is very useful if some causes are recoverable or - when writing webservers - could be translated into different status codes. Often both are useful, something representing internal details for logging and a public interface.

[IshKebab]

I agree. Is he really trying to say that e.g. errors for `std::fs::read()` should not distinguish between "file not found" and "permission denied"? It's quite common to want to react to those programmatically.

IMO Rust should provide something like thiserror for libraries, and also something like anyhow for applications. Maybe we can't design a perfect error library yet, but we can do waaay better than nothing. Something that covers 99% of uses would still be very useful, and there's plenty of precedent for that in the standard library.

[burntsushi]

Yeah I used the weasel-y "something like" for exactly these reasons. :-)