- Glasgow-haskell-users

[ANNOUNCE] GHC 9.10.1-alpha3 is now available
by Ben Gamari 15 Apr '24

15 Apr '24

The GHC developers are very pleased to announce the availability of the third alpha release of GHC 9.10.1. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.10.1-alpha3 We hope to have this release available via ghcup shortly. GHC 9.10 will bring a number of new features and improvements, including: * The introduction of the `GHC2024` language edition, building upon `GHC2021` with the addition of a number of widely-used extensions. * Partial implementation of the [GHC Proposal #281], allowing visible quantification to be used in the types of terms. * [Extension] of LinearTypes to allow linear `let` and `where` bindings ([linear let]) * The implementation of the [exception backtrace proposal], allowing the annotation of exceptions with backtraces, as well as other user-defined context * Further improvements in the info table provenance mechanism, reducing code size to allow IPE information to be enabled more widely * Javascript FFI support in the WebAssembly backend * Improvements in the fragmentation characteristics of the low-latency non-moving garbage collector. * ... and many more A full accounting of changes 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 alpha is the penultimate prerelease leading to 9.10.1. In two weeks we plan to publish a release candidate, followed, if all things go well, by the final release a week later. 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. As always, do give this release a try and open a [ticket] if you see anything amiss. Cheers, ~ Ben [release notes]: https://downloads.haskell.org/ghc/9.10.1-alpha3/docs/users_guide/9.10.1-not… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [exception backtrace]: https://github.com/ghc-proposals/ghc-proposals/pull/330 [GHC Proposal #281]: https://github.com/ghc-proposals/ghc-proposals/pull/281 [linear let]: https://github.com/ghc-proposals/ghc-proposals/pull/624 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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[ANNOUNCE] GHC 9.10.1-alpha2 is now available
by Ben Gamari 29 Mar '24

29 Mar '24

The GHC developers are very pleased to announce the availability of the second alpha release of GHC 9.10.1. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.10.1-alpha2 We hope to have this release available via ghcup shortly. GHC 9.10 will bring a number of new features and improvements, including: * The introduction of the `GHC2024` language edition, building upon `GHC2021` with the addition of a number of widely-used extensions. * Partial implementation of the [GHC Proposal #281], allowing visible quantification to be used in the types of terms. * [Extension] of LinearTypes to allow linear `let` and `where` bindings ([linear let]) * The implementation of the [exception backtrace proposal], allowing the annotation of exceptions with backtraces, as well as other user-defined context * Further improvements in the info table provenance mechanism, reducing code size to allow IPE information to be enabled more widely * Javascript FFI support in the WebAssembly backend * Improvements in the fragmentation characteristics of the low-latency non-moving garbage collector. * ... and many more A full accounting of changes 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 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. As always, do give this release a try and open a [ticket] if you see anything amiss. [release notes]: https://downloads.haskell.org/ghc/9.10.1-alpha2/docs/users_guide/9.10.1-not… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [exception backtrace]: https://github.com/ghc-proposals/ghc-proposals/pull/330 [GHC Proposal #281]: https://github.com/ghc-proposals/ghc-proposals/pull/281 [linear let]: https://github.com/ghc-proposals/ghc-proposals/pull/624 [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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[ANNOUNCE] GHC 9.10.1-alpha1 is now available
by Ben Gamari 13 Mar '24

13 Mar '24

The GHC developers are very pleased to announce the availability of the first alpha release of GHC 9.10.1. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.10.1-alpha1 We hope to have this release available via ghcup shortly. GHC 9.10 will bring a number of new features and improvements, including: * The introduction of the GHC2024 language edition, building upon GHC2021 with the addition of a number of widely-used extensions. * Partial implementation of the [GHC Proposal #281], allowing visible quantification to be used in the types of terms. * Extension of LinearTypes to allow linear `let` and `where` bindings ([linear-let]) * The implementation of the exception backtrace proposal, allowing the annotation of exceptions with backtraces, as well as other user-defined context [exception backtrace] * Further improvements in the info table provenance mechanism, reducing code size to allow IPE information to be enabled more widely * Javascript FFI support in the WebAssembly backend * Improvements in the fragmentation characteristics of the low-latency non-moving garbage collector. * ... and many more A full accounting of changes 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]. Many will notice that this release comes a fair bit later than the previously-announced schedule. While this delay has been attributable to a variety factors, the most recent cause is a set of issues with GHC 9.10's binary distributions on Windows (#24542). Instead of continuing to hold up the release process while we sort out this situation, we have instead provided this alpha without the usual assortment of Windows binary distributions. We expect to have this resolved by alpha 2; apologies to eager Windows testers for this delay. 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. As always, do give this release a try and open a [ticket] if you see anything amiss. Happy compiling, ~ Ben [release notes]: https://downloads.haskell.org/ghc/9.10.1-alpha1/docs/users_guide/9.10.1-not… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [exception backtrace]: https://github.com/ghc-proposals/ghc-proposals/pull/330 [GHC Proposal #281]: https://github.com/ghc-proposals/ghc-proposals/pull/281 [linear let]: https://github.com/ghc-proposals/ghc-proposals/pull/624

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[ANNOUNCE] GHC 9.8.2 is now available
by Zubin Duggal 23 Feb '24

23 Feb '24

The GHC developers are happy to announce the availability of GHC 9.8.2. Binary distributions, source distributions, and documentation are available on the [release page](https://www.haskell.org/ghc/download_ghc_9_8_2.html). GHC Blog Post: https://www.haskell.org/ghc/blog/20240223-ghc-9.8.2-released.html This release is primarily a bugfix release addressing many issues found in the 9.8 series. These include: * A fix for a bug where certain warnings flags were not recognised (#24071) * Fixes for bugs in the renamer and typechecker (#24084, #24134, #24279, #24083) * Fixes for bugs in the simplifier and code generator (#24160, #24242, #23628, #23659, #24160, #23862, #24295, #24370) * Fixes for some memory leaks in GHCi (#24107, #24118) * Improvements to error messages (#21097, #16996, #11050, #24196, #24275, #23768, #23784, #23778) * A fix for a recompilation checking bug where GHC may miss changes in transitive dependencies when deciding to relink a program (#23724). * And many more fixes A full accounting of changes can be found in the [release notes]. 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. Enjoy! -Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.8.2/docs/users_guide/9.8.2-notes.html

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How to build executables that will dump live backtraces
by Clinton Mead 21 Feb '24

21 Feb '24

Hi All I've noticed this is a quiet mailing list recently, but I couldn't find a more appropriate place to ask this question. Please say if there's somewhere else I should be asking. It's my understanding that one can get GHC executables to dump backtraces of all their running threads to stderr upon receiving SIGQUIT. And the way to do that is to build with 'libdw' support. We have a build system using Nix, and we're unfortunately a bit behind on GHC 9.2.2 atm, but in anycase, I noticed in a Nix develop shell when I run `ghc --info | grep libdw` I get: ,("RTS expects libdw","NO") So I instead added the following to my Haskell package overrides: ghc = old.ghc.overrideAttrs (oldAttrs: { configureFlags = oldAttrs.configureFlags ++ [ "--with-libdw-includes=${pkgs.elfutils.dev}/include" "--with-libdw-libraries=${pkgs.elfutils.out}/lib" "--enable-dwarf-unwind" ]; buildInputs = oldAttrs.buildInputs ++ [pkgs.elfutils]; }); I basically copy/pastaed this from https://github.com/input-output-hk/haskell.nix/blob/master/compiler/ghc/def… And this seems to work, now when I run `ghc --info` I get: ,("RTS expects libdw","YES") But despite building with this version of GHC, still when I send `SIGQUIT` to a process built with this version of GHC, I just get the message: "This build does not support backtraces." Now I have also been building my packages with `-g`, passing `--enable-debug-info` etc, although it's my understanding that what I've done just with building GHC with `--enable-dwarf-unwind` _should_ be enough to get a backtrace upon SIGQUIT, it might just be a poor one if the debugging symbols aren't added. But clearly I've missed something if it's not working. I'm not quite sure what set of circumstances the message "This build does not support backtraces" is displayed? Is there a runtime check to see whether the "libdw" library is actually in the library path, in addition to the requirement that GHC be built with libdw support? If that's the case, perhaps as I'm running this on NixOS I need to add something to my executable's LD_LIBRARY_PATH or something? Or is there some option I need to give GHC/Cabal to ensure that backtrace support is added to the executable's runtime as well as making sure I've compiled with GHC that's compiled with libdw support? Or is there some other runtime RTS option I need to give to my executable? As you can see, I'm completely lost about how to move forward on this, so any help would be very much appreciated. Thanks, Clinton

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[ANNOUNCE] GHC 9.6.4 is now available
by Zubin Duggal 09 Jan '24

09 Jan '24

The GHC developers are happy to announce the availability of GHC 9.6.4. Binary distributions, source distributions, and documentation are available on the [release page](https://www.haskell.org/ghc/download_ghc_9_6_4.html). This release is primarily a bugfix release addressing a few issues found in the 9.6 series. These include: * A fix for a bug where certain warnings flags were not recognised (#24071) * Fixes for a number of simplifier bugs (#23952, #23862). * Fixes for compiler panics with certain package databases involving unusable units and module reexports (#21097, #16996, #11050). * A fix for a typechecker crash (#24083). * A fix for a code generator bug on AArch64 platforms resulting in invalid conditional jumps (#23746). * Fixes for some memory leaks in GHCi (#24107, #24118) * And a few other fixes A full accounting of changes can be found in the [release notes]. 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 hacking! -Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.6.4/docs/users_guide/9.6.4-notes.html

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[ANNOUNCE] GHC 9.4.8 is now available
by Zubin Duggal 10 Nov '23

10 Nov '23

The GHC developers are happy to announce the availability of GHC 9.4.8. Binary distributions, source distributions, and documentation are available on the [release page](/download_ghc_9_4_8.html). This release is primarily a bugfix release addressing a few issues found in the 9.4 series. These include: * A fix for a recompilation checking bug where GHC may miss changes in transitive dependencies when deciding to relink a program (#23724). * A fix for a code generator bug on AArch64 platforms resulting in invalid conditional jumps (#23746). * Support for `-split-sections` on Windows. * Enabling `-split-sections` for various Linux and Windows binary distributions, enabling GHC to produce smaller binaries on these platforms. * And a few other fixes A full accounting of changes can be found in the [release notes]. 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/9.4.8/docs/users_guide/9.4.8-notes.html

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[ANNOUNCE] GHC 9.8.1 is now available
by Ben Gamari 09 Oct '23

09 Oct '23

The GHC developers are very pleased to announce the availability of the final release of GHC 9.8.1. Binary distributions, source distributions, and documentation are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.8.1 GHC 9.8 brings a number of new features and improvements, including: * Preliminary support the `TypeAbstractions` language extension, allowing types to be bound in type declarations [TypeAbstractions]. * Support for the `ExtendedLiterals` extension, providing syntax for non-word-sized numeric literals in the surface language [extended-literals] * Improved rewrite rule matching behavior, allowing limited matching of higher-order patterns * Better support for user-defined warnings by way of the `WARNING` pragma [warnings] * The introduction of the new `GHC.TypeError.Unsatisfiable` constraint, allowing more predictable user-defined type errors [unsatisfiable] * Implementation of the export deprecation proposal, allowing module exports to be marked with `DEPRECATE` pragmas [deprecated-exports] * The addition of build semaphore support for parallel compilation; with coming support in `cabal-install` this will allow better use of parallelism in multi-package builds [jsem] * More efficient representation of info table provenance information, reducing binary sizes by over 50% in some cases when `-finfo-table-map` is in use A full accounting of changes can be found in the [release notes][]. Plans for GHC's future releases can be found on the [GHC Wiki][status]. 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. Happy compiling, ~ Ben [TypeAbstractions]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0425-d… [extended-literals]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0451-s… [unsatisfiable]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0433-u… [warnings]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0541-w… [deprecated-exports]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0134-d… [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [release notes]: https://downloads.haskell.org/ghc/9.8.1/docs/users_guide/9.8.1-notes.html [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status

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Migrating GHC's real-time communications to Matrix? (#24010)
by Ben Gamari 02 Oct '23

02 Oct '23

Hello all, GHC's user and contributor documentation currently directs users to #ghc on irc.libera.chat for discussion of GHC development. However, for a variety of reasons the center-of-mass of discussion has been gradually shifting towards Matrix (#GHC:matrix.org). Given that Matrix appears to be both more active and more accessible to newcomers, I suggest that we recognize this shift in our documentation. If you agree or disagree with this proposal please leave a :thumbsup: or :thumbsdown: on [#24010] and feel free to leave a comment explaining your feelings. Cheers, - Ben [#24010]: https://gitlab.haskell.org/ghc/ghc/-/issues/24010

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[ANNOUNCE] GHC 9.8.1-rc1 is now available
by Ben Gamari 29 Sep '23

29 Sep '23

The GHC developers are very pleased to announce the availability of the release candidate of GHC 9.8.1. Binary distributions, source distributions, and documentation are available at https://downloads.haskell.org/ghc/9.8.1-rc1 GHC 9.8 will bring a number of new features and improvements, including: * Preliminary support the `TypeAbstractions` language extension, allowing types to be bound in type declarations [TypeAbstractions]. * Support for the `ExtendedLiterals` extension, providing syntax for non-word-sized numeric literals in the surface language [extended-literals] * Improved rewrite rule matching behavior, allowing limited matching of higher-order patterns * Better support for user-defined warnings by way of the `WARNING` pragma [warnings] * The introduction of the new `GHC.TypeError.Unsatisfiable` constraint, allowing more predictable user-defined type errors [unsatisfiable] * Implementation of the export deprecation proposal, allowing module exports to be marked with `DEPRECATE` pragmas [deprecated-exports] * The addition of build semaphore support for parallel compilation; with coming support in `cabal-install` this will allow better use of parallelism in multi-package builds [jsem] * More efficient representation of info table provenance information, reducing binary sizes by over 50% in some cases when `-finfo-table-map` is in use A full accounting of changes can be found in the [release notes]. This candidate includes roughly 20 new commits relative to alpha 4, including what we believe should be nearly the last changes to GHC's boot libraries. As always, GHC's release status can be found on the GHC Wiki [status]. 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. As always, do give this release a try and open a [ticket] if you see anything amiss. Happy compiling, ~ Ben [TypeAbstractions]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0425-d… [extended-literals]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0451-s… [unsatisfiable]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0433-u… [warnings]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0541-w… [deprecated-exports]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0134-d… [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [release notes]: https://downloads.haskell.org/ghc/9.8.1-alpha4/docs/users_guide/9.8.1-notes… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status

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