error-messages VS ghc-proposals

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.

This is really just a matter of how much syntax sugar you want to implement. Idris has this already, and there’s a proposal to add it to Haskell too [0]. But none of this changes the core properties of the system which make it monadic.

[0] https://github.com/ghc-proposals/ghc-proposals/issues/527

> I think Haskell needs a way to graduate (or retire) language extensions

https://github.com/ghc-proposals/ghc-proposals/pull/601

Additionally, while this proposal is focused on the simple implementation and so in the current proposal or patterns do not bind any variables as per #522, if we do get settled on syntax and then later wish to expand to allow binding variables as in #43, then the syntax is again clean and discoverable.

Yeah, a relatively natural thing would be to be able to opt-in to having the HasField instances be available in all contexts. The (not yet implemented, but accepted) "Modifiers" GHC proposal might be nice for that.

The local modules proposal imo is excellent as-is.

Why would you drop TypeFamilies? It seems fairly popular, given that it was just one vote short of getting added to GHC2021. Do you consider it a less-ideal compromise, that is subsumed by your second proposal (Core with GRTT)?

as syntax is contentious a topic as ever, David (the main proposal author) and I would like to invite you to give your input on https://github.com/ghc-proposals/ghc-proposals/pull/585, where we propose to change the syntax of the accepted proposal #522 introducing Or patterns. In particular, we'd like to know

This looks great, congratulations on completing it! I assume you didn’t get an opportunity to evaluate the delimited continuations based eff library? It would’ve been nice to see Cont included as one of the effects covered, though perhaps not available in all the systems you looked at? Maybe some future work.

I do hope qualified exports are available someday: https://github.com/ghc-proposals/ghc-proposals/pull/283

Right. Being able to disable "custom type warnings" at use sites was part of an earlier proposal (https://github.com/ghc-proposals/ghc-proposals/pull/454) but it ended up being shelved.