- Glasgow-haskell-users

[ANNOUNCE] GHC 9.6.1-alpha3 is now available
by Ben Gamari 16 Feb '23

16 Feb '23

The GHC team is very pleased to announce the availability of GHC 9.6.1-alpha3. As usual, binaries and source distributions are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.6.1-alpha3/ Beginning with GHC 9.6.1, GHC can be built as a cross-compiler to WebAssembly and JavaScript. This is an important step towards robust support for compiling Haskell to the Web, but there are a few caveats to be aware of in the 9.6 series: - Both the Javascript and WebAssembly backends are still at an early stage of development and are present in this release as a technology preview - Using GHC as a cross-compiler is not as easy as we would like it to be; in particular, there are challenges related to Template Haskell - GHC is not yet run-time retargetable; a given GHC binary targets exactly one platform, and both WebAssembly and JavaScript are considered platforms for this purpose. Cross-compilers must be built from source by their users We hope to lift all of these limitations in future releases. Additionally, 9.6.1 will include: - Significant latency improvements in the non-moving garbage collector - Efficient runtime support for delimited continuations - Improvements in compiler error messages - Numerous improvements in the compiler's memory usage See the [release notes] for a comprehensive accounting of changes in this release. As always, one can find a [migration guide] to aid in transitioning from older releases on the GHC Wiki. We have also recently started extending our release process to cover a wider set of Linux distributions. In particular, we now offer Rocky 8 and Ubuntu 20.04 binary distributions which cover RedHat-derivative and distributions using older `glibc` releases (namely 2.27), respectively. Please do give this release a try and open a [ticket] if you see anything amiss. Cheers, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/ [migration guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6 [release notes]: https://downloads.haskell.org/ghc/9.6.1-alpha3/docs/users_guide/9.6.1-notes…

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[Haskell] [ANNOUNCE] GHC 9.2.6 released
by Zubin Duggal 10 Feb '23

10 Feb '23

The GHC developers are happy to announce the availability of GHC 9.2.6. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org](https://downloads.haskell.org/ghc/9.2.6). Download Page: https://www.haskell.org/ghc/download_ghc_9_2_6.html Blog Post: https://www.haskell.org/ghc/blog/20230210-ghc-9.2.6-released.html This release is primarily a bugfix release addressing a few issues found in 9.2.5. These include: * Fixes for a number of simplifier issues typically resulting in compiler panics (#22491, #22482, #19824, #22718, #22662, #22039). * Fix for a simplifier regression in 9.2.5 that could impact runtime performance when compiling with optimisations due to duplication of expensive work (#22425). * Various stability improvments and bug fixes for the non moving and parallel GCs (#22528, #20221, #22264, #22327, #22929, #22927, #22929, #22930). * Allow certain keywords which can be used as variable names with `-XOverloadedRecordDot` (#20723). * Improvements to typechecker performance for modules with holes in type signatures (#14766) * Bump `gmp-tarballs` to a version which doesn't use the reserved `x18` register on AArch64/Darwin systems, and also has fixes for CVE-2021-43618 (#22497, #22789). * ... and a few more. See the [release notes] for a full accounting. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, 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. Happy compiling, - Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.2.6/docs/html/users_guide/9.2.6-notes.…

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[ANNOUNCE] GHC 9.6.1-alpha2 is now available
by Ben Gamari 30 Jan '23

30 Jan '23

The GHC team is very pleased to announce the availability of GHC 9.6.1-alpha2. As usual, binaries and source distributions are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.6.1-alpha2/ Beginning with GHC 9.6.1, GHC can be built as a cross-compiler to WebAssembly and JavaScript. This is an important step towards robust support for compiling Haskell to the Web, but there are a few caveats to be aware of in the 9.6 series: - Both the Javascript and WebAssembly backends are still at an early stage of development and are present in this release as a technology preview - Using GHC as a cross-compiler is not as easy as we would like it to be; in particular, there are challenges related to Template Haskell. - GHC is not yet run-time retargetable; a given GHC binary targets exactly one platform, and both WebAssembly and JavaScript are considered platforms for this purpose. Cross-compilers must be built from source by their users We hope to lift all of these limitations in future releases. Additionally, 9.6.1 will include: - Significant latency improvements in the non-moving garbage collector - Efficient runtime support for delimited continuations - Improvements in compiler error messages - Numerous improvements in the compiler's memory usage See the [release notes] for a comprehensive accounting of changes in this release. As always, one can find a [migration guide] to aid in transitioning from older releases on the GHC Wiki. We have also recently started extending our release process to cover a wider set of Linux distributions. In particular, we now offer Rocky 8 and Ubuntu 20.04 binary distributions which cover RedHat-derivative and distributions using older `glibc` releases (namely 2.27), respectively. Please do give this release a try and open a [ticket] if you see anything amiss. Cheers, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/ [migration-guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6 [release notes]: https://downloads.haskell.org/ghc/9.6.1-alpha2/docs/users_guide/9.6.1-notes…

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How to fool the divergence checker in ghc 9
by Michael Sperber 20 Jan '23

20 Jan '23

I'm trying to port Conal Elliott's ConCat plugin from ghc 8 to 9, and the divergence checker foils me. Background: The plugin works by transforming calls to a pseudo-function toCcc' defined like so: -- | Pseudo function to trigger rewriting to TOCCC form. toCcc' :: forall k a b. (a -> b) -> (a `k` b) toCcc' _ = oops "toCcc' called" {-# NOINLINE toCcc' #-} For ghc 8, oops was defined like so: module ConCat.Misc where -- | Pseudo function to fool GHC's divergence checker. oops :: String -> b oops str = errorWithStackTrace ("Oops: "++str) {-# NOINLINE oops #-} ... but unfortunately, ghc 9 is not so easily fooled and reports <A>x for toCcc'. Is there any way to prevent this that works for ghc 9? Help would be much appreciated! -- Regards, Mike

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[ANNOUNCE] GHC 9.6.1-alpha1 is now available
by Ben Gamari 16 Jan '23

16 Jan '23

The GHC team is very pleased to announce the availability of GHC 9.6.1-alpha1. As usual, binaries and source distributions are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.6.1-alpha1/ This is the first alpha release in the 9.6 series which will bring a number of exciting features: * A new Javascript code generation backend * A new WebAssembly code generation backend, * Significant latency improvements in the non-moving garbage collector * Support for loading of multiple components in GHCi * Efficient support for delimited continuations * Improvements in error messages * Numerous improvements in compiler-residency Note that both the Javascript and WebAssembly backends are still in a state of infancy and are present in this release as a technology preview; we hope that they will mature considerably before the final 9.6.1 release. Please give this release a try and open a [ticket] if you see anything amiss. Cheers, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/

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Will there be a GHC 9.2.6?
by Clinton Mead 28 Dec '22

28 Dec '22

Hi All I just noticed Haskell Language Server (HLS) 1.9 has been released, which supports GHC 9.2.5. My organisation is currently using GHC 9.2.2 and I don't see any immediate need to jump to GHC 9.4, it would be good to settle on the latest most stable version of the GHC 9.2 series as it includes all the features we need at the moment. Also I understand that HLS tends to have long term(ish) support for the latest GHC in a release series. I'd rather not do this upgrade twice so I was just wondering whether it has been decided or not whether there will be a 9.2.6 release (if this is still unknown that's okay). I did notice this page: https://gitlab.haskell.org/ghc/ghc/-/milestones/385 but was unsure whether this page was autogenerated or a deliberate indication that there will be a GHC 9.2.6 at some point. (I understand one can do source builds of HLS for non-supported versions but I'd prefer to just allow developers to use an off the shelf HLS plugin for their favoured editor along with a HLS pin in Nix). Thanks, Clinton

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[ANNOUNCE] GHC 9.4.4 is now available
by Ben Gamari 25 Dec '22

25 Dec '22

The GHC developers are happy to announce the availability of GHC 9.4.4. Binary distributions, source distributions, and documentation are available at downloads.haskell.org [1]. This release is primarily a bugfix release. Bugs fixed include: * An issue where the wrong labels were used in the eventlog for events emitted when using info table profiling which was broken in 9.4.3 (#22452) * Fix a long standing bug where invalid eventlogs would be produced with long command-lines (#20221) * Fix a regression in eta-expansion which resulted in serious performance regressions in 9.4.3 (#22424) * Fix the `-fdefer-diagnostics` flag (#22391) * Fixes to several subtle compiler panics (#22491, #22416, #22549, #22475, #22039) * Add necessary write barriers to `IORef` operations, avoiding potential soundness issues on architectures with weakly-ordered memory models (#22468) Note that, as GHC 9.4 is the first release series where the release artifacts are all generated by our new Hadrian build system, it is possible that there will be packaging issues. If you enounter trouble while using a binary distribution, please open a [ticket]. Likewise, if you are a downstream packager, do consider migrating to [Hadrian] to run your build; the Hadrian build system can be built using `cabal-install`, `stack`, or the in-tree [bootstrap script]. See the accompanying [blog post] for details on migrating packaging to Hadrian. We would also like to emphasize that GHC 9.4 must be used in conjunction with Cabal-3.8 or later. This is particularly important for Windows users due to changes in GHC's Windows toolchain. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, 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. Happy Haskelling, - Ben [1]: https://downloads.haskell.org/ghc/9.4.4 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [bootstrap script]: https://gitlab.haskell.org/ghc/ghc/-/blob/e2520df3fffa0cf22fb19c5fb872832d1… [Hadrian]: https://gitlab.haskell.org/ghc/ghc/-/blob/e2520df3fffa0cf22fb19c5fb872832d1… [blog post]: https://www.haskell.org/ghc/blog/20220805-make-to-hadrian.html

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[ANNOUNCE] GHC 9.4.3 is now available
by Ben Gamari 09 Nov '22

09 Nov '22

The GHC developers are happy to announce the availability of GHC 9.4.3. Binary distributions, source distributions, and documentation are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.4.3 This release is primarily a bugfix release addressing a few issues found in 9.4.2. These include: * An issue where recursively calls could be speculatively evaluated, resulting in non-termination (#20836) * A code generation issue in the AArch64 native code generator backend resulting in incorrect runtime results in some circumstances (#22282) * A crash on Darwin when running executables compiled with IPE support (#22080) * A long-standing interface-file determinism issue where full paths would leak into the interface file (#22162) * A bug in the `process` library where file handles specified as `NoStream` would still be usable in the child (process#251) Note that, as GHC 9.4 is the first release series where the release artifacts are all generated by our new Hadrian build system, it is possible that there will be packaging issues. If you enounter trouble while using a binary distribution, please open a [ticket]. Likewise, if you are a downstream packager, do consider migrating to [Hadrian] to run your build; the Hadrian build system can be built using `cabal-install`, `stack`, or the in-tree [bootstrap script]. See the accompanying [blog post] for details on migrating packaging to Hadrian. We would also like to emphasize that GHC 9.4 must be used in conjunction with Cabal-3.8 or later. This is particularly important for Windows users due to changes in GHC's Windows toolchain. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, 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. Happy Haskelling, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [bootstrap script]: https://gitlab.haskell.org/ghc/ghc/-/blob/e2520df3fffa0cf22fb19c5fb872832d1… [Hadrian]: https://gitlab.haskell.org/ghc/ghc/-/blob/e2520df3fffa0cf22fb19c5fb872832d1… [blog post]: https://www.haskell.org/ghc/blog/20220805-make-to-hadrian.html

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GitLab maintenance today
by Ben Gamari 07 Nov '22

07 Nov '22

Hi all, Today we will be doing some maintenance on gitlab.haskell.org to address #22418. I can't yet say precisely when the outage will begin but I do expect there to be one. I will try to provide at least 30 minutes notice. Cheers, - Ben

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[Haskell] [ANNOUNCE] GHC 9.2.5 released
by Zubin Duggal 07 Nov '22

07 Nov '22

The GHC developers are very happy to at announce the availability of GHC 9.2.5. Binary distributions, source distributions, and documentation are available at [`downloads.haskell.org`](https://downloads.haskell.org/ghc/9.2.5). Download Page: https://www.haskell.org/ghc/download_ghc_9_2_5.html Blog Post: https://www.haskell.org/ghc/blog/20221107-ghc-9.2.5-released.html This release is primarily a bugfix release addressing a few issues found in 9.2.4. These include: * Code generation issues in the AArch64 native code generator backend resulting in incorrect runtime results in some circumstances (#22282, #21964) * Fixes for a number of issues with the simplifier leading to core lint errors and suboptimal performance (#21694, #21755, #22114) * A long-standing interface-file determinism issue where full paths would leak into the interface file (#22162) * A runtime system bug where creating empty mutable arrays resulted in a crash (#21962) - ... and a few more. See the [release notes] for a full accounting. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, 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. Happy compiling, - Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.2.5/docs/html/users_guide/9.2.5-notes.…

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