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GHC 9.12.2-rc1 is now available
by Ben Gamari 27 Feb '25

27 Feb '25

The GHC developers are happy to announce the availability of the first and likely final release candidate of GHC 9.12.2. This is an important bug-fix release resolving a significant correctness issue present in 9.12.1 (#25653). In accordance with our under-discussion [release policies] this candidate will have a two-week testing window. The final 9.12.2 release will likely come the week of 12 March 2025. As always, if you find anything amiss please open a [ticket]. Happy Haskelling! - Ben [release policies]: https://gitlab.haskell.org/ghc/ghc-hq/-/merge_requests/38 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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GHC API stability: draft report of actions
by Facundo Domínguez 27 Feb '25

27 Feb '25

Dear GHC devs, As part of the initiative to stabilize the GHC API [1], I've written a draft report [2] proposing actions to address some of the collected feedback. Some of these actions can potentially affect the processes used to maintain GHC, so your input is very much welcome to assess these or to propose other actions. [1] https://discourse.haskell.org/t/ghc-api-stability-update-3/11407 [2] https://docs.google.com/document/d/1w88bz03bZ9J7BP1WDxdpUTLqGrV4C9MAM1C06dD… Best, Facundo -- All views and opinions expressed in this email message are the personal opinions of the author and do not represent those of the organization or its customers.

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How do I get warnings out of GHC.typecheckModule with GHC 9.12?
by Erdi, Gergo 25 Feb '25

25 Feb '25

PUBLIC Hi, I'm trying to use GHC.typecheckModule to typecheck a module. On GHC 9.8, this function used to expose renamer/typechecker-originating warnings to the GhcMonad that it is run in. However, as of e7a956623b7d71e50fa86fee83459d2611c423b8, the underlying function hscTypecheckRename has been refactored and now seems to discard warnings. At least, that's my read of the situation. End-to-end, what I'm seeing is that using GHC.typecheckModule, I can see the warnings come out from hscTypechekcRenameWithDiagnostics, but they never make it to printOrThrow. So how is GHC.typecheckModule supposed to be used by API clients in such a way that warnings are still passed to the logger stack? Thanks, Gergo ---------------------------------------------------------------------- This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries together with Standard Chartered Bank’s Privacy Policy via our public website. ---------------------------------------------------------------------- This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries together with Standard Chartered Bank’s Privacy Policy via our main Standard Chartered PLC (UK) website at sc. com

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GHC 9.6.7 rc2 available
by Luite Stegeman 16 Feb '25

16 Feb '25

The GHC developers are very pleased to announce the availability of the second release candidate of GHC 9.6.7. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.6.7-rc2 We hope to have this release available via ghcup shortly. Haskell Language Server does not yet build with GHC 9.6.7. See the note below. If all goes according to plan, we expect that the final release of GHC 9.6.7 will be available on February 28. Release candidate 2 contains the following changes relative to (the unannounced) release candidate 1: - the symbol atomic_inc64 is no longer exported from the RTS GHC 9.6.7 will bring a number of fixes, including: - GHC’s internal Unique type has been widened to 64-bits on 32-bit architectures, avoiding potential miscompilations on large projects. - Fix a runtime crash when using the compacting GC, caused by black holes in large objects. - Added new flags -fspec-eval and -fspec-eval-dictfun to allow switching off speculative evaluation. The following libraries have been updated since GHC 9.6.6: - base-4.18.3.0 (the version number in the rc2 release notes is incorrect) - filepath-1.4.301.0 - unix-2.8.6.0 - bytestring-0.11.5.4 - array-0.5.8.0 A more detailed description can be found in the [release notes] and a full list of changes in [GHC!13841] and [GHC!13891] Note about Haskell Language Server and building GHC 9.8+: The change of Unique to 64 bit [GHC#22010] adds the exported symbol ghc_unique_counter64 to the RTS. Unfortunately it's impossible to avoid this without breaking other things. If you encounter a linker error related to ghc_unique_counter64 when building GHC (or building a GHC-derived package like ghc-lib-parser) with GHC 9.6.7, you probably have to add this [fix] to the program you're building. At the time of writing all released GHC 9.8 versions are affected, as well as the latest version of ghc-lib-parser-9.8 on hackage (which is a dependency of Haskell Language Server). We would like to thank GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, the Haskell Foundation, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. Please give this release candidate a try and open a [ticket] if you see anything amiss. ~ Luite [release notes]: https://downloads.haskell.org/ghc/9.6.7-rc2/docs/users_guide/9.6.7-notes.ht… [GHC!13841]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13841 [GHC!13891]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13891 [GHC#22010]: https://gitlab.haskell.org/ghc/ghc/-/issues/22010 [fix] https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13743 [ticket] https://gitlab.haskell.org/ghc/ghc/-/issues/new

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GHC 9.6.7 rc2 available
by Luite Stegeman 16 Feb '25

16 Feb '25

The GHC developers are very pleased to announce the availability of the second release candidate of GHC 9.6.7. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.6.7-rc2 We hope to have this release available via ghcup shortly. Haskell Language Server does not yet build with GHC 9.6.7. See the note below. If all goes according to plan, we expect that the final release of GHC 9.6.7 will be available on February 28. Release candidate 2 contains the following changes relative to (the unannounced) release candidate 1: - the symbol atomic_inc64 is no longer exported from the RTS GHC 9.6.7 will bring a number of fixes, including: - GHC’s internal Unique type has been widened to 64-bits on 32-bit architectures, avoiding potential miscompilations on large projects. - Fix a runtime crash when using the compacting GC, caused by black holes in large objects. - Added new flags -fspec-eval and -fspec-eval-dictfun to allow switching off speculative evaluation. The following libraries have been updated since GHC 9.6.6: - base-4.18.3.0 (the version number in the rc2 release notes is incorrect) - filepath-1.4.301.0 - unix-2.8.6.0 - bytestring-0.11.5.4 - array-0.5.8.0 A more detailed description can be found in the [release notes] and a full list of changes in [GHC!13841] and [GHC!13891] Note about Haskell Language Server and building GHC 9.8+: The change of Unique to 64 bit [GHC#22010] adds the exported symbol ghc_unique_counter64 to the RTS. Unfortunately it's impossible to avoid this without breaking other things. If you encounter a linker error related to ghc_unique_counter64 when building GHC (or building a GHC-derived package like ghc-lib-parser) with GHC 9.6.7, you probably have to add this [fix] to the program you're building. At the time of writing all released GHC 9.8 versions are affected, as well as the latest version of ghc-lib-parser-9.8 on hackage (which is a dependency of Haskell Language Server). We would like to thank GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, the Haskell Foundation, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. Please give this release candidate a try and open a [ticket] if you see anything amiss. ~ Luite [release notes]: https://downloads.haskell.org/ghc/9.6.7-rc2/docs/users_guide/9.6.7-notes.ht… [GHC!13841]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13841 [GHC!13891]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13891 [GHC#22010]: https://gitlab.haskell.org/ghc/ghc/-/issues/22010 [fix] https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13743 [ticket] https://gitlab.haskell.org/ghc/ghc/-/issues/new P.S. Apologies if you already received this mail.

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GHC 9.6.7 rc2 available
by Luite Stegeman 14 Feb '25

14 Feb '25

The GHC developers are very pleased to announce the availability of the second release candidate of GHC 9.6.7. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.6.7-rc2 We hope to have this release available via ghcup shortly. Haskell Language Server does not yet build with GHC 9.6.7. See the note below. If all goes according to plan, we expect that the final release of GHC 9.6.7 will be available on February 28. Release candidate 2 contains the following changes relative to (the unannounced) release candidate 1: - the symbol atomic_inc64 is no longer exported from the RTS GHC 9.6.7 will bring a number of fixes, including: - GHC’s internal Unique type has been widened to 64-bits on 32-bit architectures, avoiding potential miscompilations on large projects. - Fix a runtime crash when using the compacting GC, caused by black holes in large objects. - Added new flags -fspec-eval and -fspec-eval-dictfun to allow switching off speculative evaluation. The following libraries have been updated since GHC 9.6.6: - base-4.18.3.0 (the version number in the rc2 release notes is incorrect) - filepath-1.4.301.0 - unix-2.8.6.0 - bytestring-0.11.5.4 - array-0.5.8.0 A more detailed description can be found in the [release notes] and a full list of changes in [GHC!13841] and [GHC!13891] Note about Haskell Language Server and building GHC 9.8+: The change of Unique to 64 bit [GHC#22010] adds the exported symbol ghc_unique_counter64 to the RTS. Unfortunately it's impossible to avoid this without breaking other things. If you encounter a linker error related to ghc_unique_counter64 when building GHC (or building a GHC-derived package like ghc-lib-parser) with GHC 9.6.7, you probably have to add this [fix] to the program you're building. At the time of writing all released GHC 9.8 versions are affected, as well as the latest version of ghc-lib-parser-9.8 on hackage (which is a dependency of Haskell Language Server). We would like to thank GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, the Haskell Foundation, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. Please give this release candidate a try and open a [ticket] if you see anything amiss. ~ Luite [release notes]: https://downloads.haskell.org/ghc/9.6.7-rc2/docs/users_guide/9.6.7-notes.ht… [GHC!13841]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13841 [GHC!13891]: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13891 [GHC#22010]: https://gitlab.haskell.org/ghc/ghc/-/issues/22010 [fix] https://gitlab.haskell.org/ghc/ghc/-/merge_requests/13743 [ticket] https://gitlab.haskell.org/ghc/ghc/-/issues/new

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CI instability
by Ben Gamari 09 Feb '25

09 Feb '25

Hi all, It appears that there is currently some CI instability arising from Docker registry changes made recently. I am investigating. Cheers, - Ben

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Docker registry outage
by Ben Gamari 08 Feb '25

08 Feb '25

Hi all, This evening, starting at 1800 EST, I plan on bringing down the Docker registry for an upgrade; I expect that the maintenance will take one or two hours. Docker images will be unable to be pushed or pulled for this duration. While the CI runners generally cache images locally, there is a non-negligible chance that some jobs would fail during this period. To mitigate this, I will keep an eye on the runner pool and pause adversely affected runners during the outage. As always, let me know if you have any questions or concerns about the timing of this maintenance. Cheers, - Ben

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GHC 9.10 release tags missing from Git
by Erdi, Gergo 06 Feb '25

06 Feb '25

PUBLIC Hi, The latest release tag for the ghc-9.10 branch on the Git repo is ghc-9.10.1-release, even though we've had 9.10.2 and 9.10.3 in the meantime. Could someone who knows the exact commits tag them please? Thanks, Gergo ---------------------------------------------------------------------- This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries together with Standard Chartered Bank’s Privacy Policy via our public website. ---------------------------------------------------------------------- This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries together with Standard Chartered Bank’s Privacy Policy via our main Standard Chartered PLC (UK) website at sc. com

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Google Summer of Code Project Ideas
by Aaron Allen 28 Jan '25

28 Jan '25

Haskell will be applying for the Google Summer of Code 2025 program and it would be great to have some project ideas involving GHC. If anything comes to mind, please submit an idea proposal using the instructions found here: https://summer.haskell.org/ideas.html. Thanks, Aaron

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