- ghc-devs - Haskell.org

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 15 Feb '25

15 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 13 Feb '25

13 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 07 Feb '25

07 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 05 Feb '25

05 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 27 Jan '25

27 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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CLC Elections January 2025
by Andrew Lelechenko 26 Jan '25

26 Jan '25

Core Libraries Committee seeks nominations for three expiring seats (including my own). I’m specifically sending this email to ghc-devs, because im my opinion CLC can benefit from representatives of GHC team. # What is CLC? CLC is a volunteer body, primarily tasked with management of API of `base` package, but also owning so-called Core Libraries and responsible for PVP. You can find out more at https://github.com/haskell/core-libraries-committee/ # Who should apply? Anyone who meets the following criteria should apply: * Candidates should have enough bandwidth to review merge requests to `base` on a semi-frequent basis (~3-4 per month), and sustain this for their 3 years term in a healthy manner. * Candidates should be able to contribute opinions and analysis to issues raised by the community as a part of the CLC proposal process on a semi-frequent basis (~7 per month). * Candidates should be good communicators, and at least be able to articulate to the CLC team when they will be available vs. unavailable. * Candidates should be productive, and be able to follow through on merge requests and conversations to their completion in a diligent and timely manner. We encourage any and all who satisfy these requirements to apply. Please note that we are not looking for the biggest galaxy brain in the room -- quite the opposite. We are looking for productive, motivated individuals who want to help support the ecosystem that we love. As such, we hope to build a broad sample of the community. # How can I apply? To apply for one of these positions, send an email to clc.nominations.2025(a)gmail.com that consists of the following data: * The subject “CLC Election September 2025 - {your name}”. * Why you think you’re a good fit given the above criteria. * If applicable, please point us to some code you’ve written. Please apply before Feb 2. Best regards, Andrew

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History of DH contributions
by Vladislav Zavialov 20 Jan '25

20 Jan '25

Dear GHC devs, I’ll be soon publishing a task breakdown for DH (as I see it). In addition to the planned changes, I decided to include the recent history of related work (2018–2024) in the form of links to specific proposals, issues, and commits. Here’s an example of what a single section is going to look like: https://discourse.haskell.org/uploads/default/optimized/2X/4/4954f5fac0a03e… and there will be about 50 of such sections. However, as the volume of GHC commits and issues is too high for me to go through all of them, I had to limit the scope and focus on my own work. If you have any DH-related contributions that you want represented, please let me know and I’ll try to find a place to include a reference. Vlad

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[PSA]: Correctness issue in GHC-9.12
by Andreas Klebinger 17 Jan '25

17 Jan '25

A bug in 9.12.1 was reported and confirmed (ghc bug https://gitlab.haskell.org/ghc/ghc/-/issues/25653) which can lead to incorrect runtime results in compiled programs. In particular this seems to happen for sub-word divisions with a known divisor when optimizations are enabled and affects at least the x86 backend, although it’s likely that other backends are also affected. We plan to release a bug fix release 9.12.2 in the near future to address this issue and recommend people do not upgrade until then.

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