September 2025 - Glasgow-haskell-users

GHC 9.12.3-rc1 is now available
by Zubin Duggal 22 Sep '25

22 Sep '25

The GHC developers are very pleased to announce the availability of the release candidate for GHC 9.12.3. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][] and via [GHCup](https://www.haskell.org/ghcup/). GHC 9.12.3 is a bug-fix release fixing several issues of a variety of severities and scopes. A full accounting of these fixes can be found in the [release notes][]. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. This release candidate will have a two-week testing period. If all goes well the final release will be available the week of 2 October 2025. We would like to thank Well-Typed, Tweag I/O, Juspay, QBayLogic, Channable, Serokell, 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. As always, do give this release a try and open a [ticket][] if you see anything amiss. [release notes]: https://gitlab.haskell.org/ghc/ghc/-/blob/ghc-9.12/docs/users_guide/9.12.3-… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [downloads.haskell.org] https://downloads.haskell.org/ghc/9.12.3-rc1 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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GHC 9.14.1-alpha2 is now available
by Ben Gamari 15 Sep '25

15 Sep '25

The GHC developers are very pleased to announce the availability of the second alpha prerelease of GHC 9.14.1. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org] GHC 9.14 will bring a number of new features and improvements, including: * Significant improvements in specialisation: * The `SPECIALISE` pragma now allows use of type application syntax * The `SPECIALISE` pragma can be used to specialise for expression arguments as well as type arguments. * Specialisation is now considerably more reliable in the presence of `newtype`s * Significant improvements in the GHCi debugger * Record fields can be defined to be non-linear when `LinearTypes` is enabled. * `RequiredTypeArgments` can now be used in more contexts * SSE/AVX2 support in the x86 native code generator backend * A major update of the Windows toolchain * ... and many more A full accounting of changes can be found in the [release notes]. Given the many specialisation improvements and their potential for regression, we would very much appreciate testing and performance characterisation on downstream workloads. Observant readers of these prerelease announcements will note that polymorphic specialisation has been dropped from alpha 2. This measure was taken out of an abundance of caution after finding a miscompilation during testing of alpha 1. While this bug will be fixed in the next alpha, we expect to keep polymorphic specialisation disabled by default in the final release. Users needing more aggressive specialisation can explicitly enable this feature with the `-fpolymorphic-specialisation` flag. Depending upon our experience with 9.14.1, we may enable this feature by default in a later minor release. This is the second of three expected alpha prereleases. We expect the next (third) alpha will come 23 Sept. 2025, with the release candidate coming 7 Oct. 2025. We would like to thank the Zw3rk stake pool, Well-Typed, Mercury, Channable, Tweag I/O, Serokell, 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 have made the Haskell ecosystem what it is today. As always, do give this release a try and open a [ticket] if you see anything amiss. [downloads.haskell.org] https://downloads.haskell.org/ghc/9.14.1-alpha2 [release notes]: https://downloads.haskell.org/ghc/9.14.1-alpha2/docs/users_guide/9.14.1-not… [ticket]: https://gitlab.haskell.org/ghc/homepage/-/issues/new

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GHC 9.10.3 is now available
by Zubin Duggal 11 Sep '25

11 Sep '25

The GHC developers are very pleased to announce the availability of the final release for GHC 9.10.3. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][]. GHC 9.10.3 is a bug-fix release fixing many issues of a variety of severities and scopes, including: * Fix a number of crashes in the compiler frontend (#25960, #25004, #25056) * Fix incorrect results in the NCG (#25601, #26061) * Support for far jumps in the AArch64 NCG (#24648) * A fix for a segfault in the RTS when running certain code involving STM (#26205) * And many more! A full accounting of these fixes can be found in the [release notes][]. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. We would like to thank Well-Typed, Tweag I/O, Juspay, QBayLogic, Channable, Serokell, 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. As always, do give this release a try and open a [ticket][] if you see anything amiss. [release notes]: https://downloads.haskell.org/~ghc/9.10.3/docs/users_guide/9.10.3-notes.html [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [downloads.haskell.org] https://downloads.haskell.org/ghc/9.10.3 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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