error-message-index VS error-messages

Significant effort is going into resolving this issue right now and things should be much improved in 9.6. We already have https://errors.haskell.org/ which catalogues many errors with descriptions and examples. The asspciated error codes will be added to all errors once 9.6 is release for easy reference.

We're also delighted to announce integration with errors.haskell.org, which already has a couple of GHCup codes documented, e.g. https://errors.haskell.org/messages/GHCup-00010/

To support the Haskell Foundation’s Haskell Error Index initiative, all Stack error messages generated by Stack itself begin with an unique code in the form [S-nnnn], where nnnn is a four-digit number.

I don't think the resolved issues are actually ones about error messages. They largely seem to be meta issues about the project. As far as I know nothing that project has done has made it into a released GHC yet, but GHC 9.6 will have unique error codes for each error pointing to an entry on https://errors.haskell.org/. Both the codes and the website are achievements of that project, specifically under its error-messages-index incarnation. If you'd like to contribute you may like to read https://github.com/haskellfoundation/error-message-index/blob/main/CONTRIBUTING.md or post a message introducing yourself on https://github.com/haskell/error-messages/issues/new.

The GHC issue tracker or the error message improvement repo are two such places to get clarification (and potentially improve the message even if it turns out to be technically correct).

Indeed there is a ticket and the error message is somewhat better in 9.4 although it still doesn't mention the guard.

Note that the Num literal issue is tracked here and there seems to be a good suggestion to fix it: https://github.com/haskell/error-messages/issues/5#issuecomment-1040788806

I think it would be great to post this over at https://github.com/haskell/error-messages too so that we can track it more easily than here on Reddit.

Also, reminder that https://github.com/haskell/error-messages exists to track these kind of issues. Feel free to open an issue there.

If you are able to articulate what aspects of the error messages you find hard to understand, please do open an issue on https://github.com/haskell/error-messages. (Or reply here then I can open an issue for you if you don't have a github account.) It doesn't have to be a concrete suggestion for improvement, even just knowing which messages are bad can be useful.

Do you know about https://github.com/haskell/error-messages

The error message is at the least very unhelpful. Please report it on https://github.com/haskell/error-messages/issues/new

Please do open an issue at https://github.com/haskell/error-messages. The issue itself can be as simple as just summarizing what you wrote here, it doesn't have to immediately suggest a good alternative. That issue tracker is in the first place intended to document all error messages that Haskellers struggle with.

Do check out https://github.com/haskell/error-messages. We have a related discussion here: https://github.com/haskell/error-messages/issues/5, but I think perhaps a separate issue for this case would be good to have.