Support GHC 9.2

[fendor]

GHC 9.2 rc1 is out, and ghcide aims to implement GHC 9.2 support ASAP.

The last dependency of ghcide that doesn't compile with GHC 9.2 (via head.hackage) is retrie and it would be great if we could upgrade soon!

[pepeiborra]

@fendor would you be interested in sending a PR? I can get it merged next week and release to Hackage

[fendor]

I'll have a crack at it tomorrow!

[fendor]

Unfortunately, I failed to upgrade to latest ghc-exactprint and can't promise a PR any time soon.

[pepeiborra]

Maybe we should look into dropping the dependency from ghcide then?

[alanz]

@fendor Is your work in progress available anywhere? I am keen to give this a go, to confirm that the new ghc-exactprint actually works.

[alanz]

And I believe the only sane way forward is as with ghc-exactprint, the current version works for GHC < 9.2, a later one supports GHC 9.2 and up.

[fendor]

I pushed my WIP to https://github.com/fendor/retrie/tree/wip/ghc92, but don't expect much, I struggled with understanding what changed between ghc-exactprint versions, and what has moved to GHC, etc...

[mouse07410]

Maybe we should look into dropping the dependency from ghcide then?

I'd say it would be the best. Ideal.

[pepeiborra]

Maybe we should look into dropping the dependency from ghcide then?

I'd say it would be the best. Ideal.

Thanks for your input. Unfortunately the challenge here is created by the new encoding of ghc-exactprint included in ghc-9.2 and not so much by retrie, so dropping the retrie dependency would only make things worse for ghcide, since we'd need to deal with ghc-exactprint ourselves.

[alanz]

FWIW, I have an updated ghc-exactprint for GHC 9.2.1, not released yet. There are a few minor niggles.
I think it may be best to publish it, and my update for retrie to use it, so that the build gets unblocked.
It will have a few infelicities, which can be solved later, but will at least not block the bigger project.

[mouse07410]

@alanz yes, please do publish it!

[alanz]

I am down to ten failing tests, end is in sight, will get something out on the weekend at the latest (failing or not)