- ghc-devs - Haskell.org

ambiguous record field (but not *that* kind of ambiguous record field)
by Richard Eisenberg 16 May '22

16 May '22

Hi all, On a project I'm working on, I wish to declare something like data Rec = MkRec { field :: forall a. SomeConstraint a => ... } where the ... contains no mention of `a`. Even with https://github.com/ghc-proposals/ghc-proposals/pull/448 <https://github.com/ghc-proposals/ghc-proposals/pull/448>, I think there is no way to avoid the ambiguity when setting `field`. Is that correct? If so, what shall we do about it? The natural answer is somehow to write ... MkRec { field @a = ... } ... but that would break significant new syntactic ground. (Maybe it's good new syntactic ground, but it would still be very new.) Thanks, Richard

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Welcome to Bryan (Devops Engineer)
by Matthew Pickering 16 May '22

16 May '22

Hi all, Bryan has been hired by the Haskell foundation to work on devops problems in the Haskell ecosystem. His first day is today! At least initially he will be working closely with the GHC team to shore up CI infrastructure and other devops tasks. If you see him around make sure to say hello, especially if you've got a complaint about CI ;) His username is chreekat. Cheers, Matt

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Deprecation of GHCi's tag generation feature, starting with GHC 9.4
by Hécate 15 May '22

15 May '22

Hello devs, Last year was discussed the deprecation of GHCi's tag generation feature, as it had become a liability with recent additions to the language, like Unboxed Sums¹. The deprecation process starts with GHC 9.4, and merge request !6325². TL;DR: The ghc-tags tool has been elected to replace the tags feature. This is being documented in the "Tags" wiki page³. You are invited to help with broadcasting this announcement to your fellow Haskell users. I will post on Reddit and the Haskell Discourse but increasing the coverage of this will be important. Cheers, Hécate ¹ https://gitlab.haskell.org/ghc/ghc/-/issues/19884 ² https://gitlab.haskell.org/ghc/ghc/-/merge_requests/6325 ³ https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/GHCi/Tags -- Hécate ✨ 🐦: @TechnoEmpress IRC: Hecate WWW: https://glitchbra.in RUN: BSD

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Extra file in GHC repo
by Simon Peyton Jones 13 May '22

13 May '22

Hi devs I've started to get this a lot bash$ git rebase origin/master First, rewinding head to replay your work on top of it... error: The following untracked working tree files would be overwritten by checkout: docs/index.html Please move or remove them before you switch branches. Aborting fatal: Could not detach HEAD Removing docs/index.html makes things work again. What am I doing wrong? Simon

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stack exec -- pacman broken
by Shayne Fletcher 11 May '22

11 May '22

this isn't exactly a GHC issue but perhaps someone knows how to get it resolved? (suspecting commercial/stack i've raised [this issue]( https://github.com/commercialhaskell/stack/issues/5732) there). tl;dr `stack exec -- pacman -S ...` like commands required for building GHC on windows are broken and have been for sometime ghc-lib CI runs this command on windows, ``` stack --resolver lts-18.23 exec -- pacman -S autoconf automake-wrapper make patch python tar mintty --noconfirm ``` this normally works ok but as of today, ``` warning: database file for 'clang32' does not exist (use '-Sy' to download) warning: mintty-1~3.6.0-1 is up to date -- reinstalling error: failed to prepare transaction (could not find database) ``` in another project (ghc-lib-parser-ex), a similar command (different compiler version/stack yaml) has been producing the following reliably long enough that i'm sorry to say i just gave up testing it windows. ``` :: File /var/cache/pacman/pkg/automake1.9-1.9.6-3-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] error: automake1.10: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: automake1.11: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: automake1.12: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: automake1.13: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: automake1.14: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: automake1.15: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust :: File /var/cache/pacman/pkg/automake1.10-1.10.3-4-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] :: File /var/cache/pacman/pkg/automake1.11-1.11.6-4-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] :: File /var/cache/pacman/pkg/automake1.12-1.12.6-4-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] :: File /var/cache/pacman/pkg/automake1.13-1.13.4-5-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] :: File /var/cache/pacman/pkg/automake1.14-1.14.1-4-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] error: automake1.16: signature from "David Macek <david.macek.0(a)gmail.com>" is unknown trust error: failed to commit transaction (invalid or corrupted package) :: File /var/cache/pacman/pkg/automake1.15-1.15.1-2-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] :: File /var/cache/pacman/pkg/automake1.16-1.16.3-1-any.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)). Do you want to delete it? [Y/n] Errors occurred, no packages were upgraded. ``` -- Shayne Fletcher

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Gitlab problem
by Simon Peyton Jones 10 May '22

10 May '22

Friends I am abruptly unable to push or pull to the GHC repo. E.g. 'git fetch' just hangs. Yet ssh git(a)gitlab.haskell.org seems to succeed with PTY allocation request failed on channel 0 Welcome to GitLab, @simonpj! Connection to gitlab.haskell.org closed. How could I debug this? I'm on WSL. My network appears to be fine. Thanks. I'm totally stalled. Simon

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Deprecation process for GHC.Pack
by Hécate 09 May '22

09 May '22

Hello fellow devs, Just an email to signal the start of the deprecation process of GHC.Pack, with the three-releases cycle: 1. By prose (GHC 9.6) (#21541 <https://gitlab.haskell.org/ghc/ghc/-/issues/21541>) 2. By warning (GHC 9.8) (#21540 <https://gitlab.haskell.org/ghc/ghc/-/issues/21540>) 3. By error (GHC 9.10) (#21536 <https://gitlab.haskell.org/ghc/ghc/-/issues/21536>) You can read more about the whole thing here: https://gitlab.haskell.org/ghc/ghc/-/issues/21461 Cheers, have a nice week! -- Hécate ✨ 🐦: @TechnoEmpress IRC: Hecate WWW:https://glitchbra.in RUN: BSD

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Specialising NOINLINE functions
by Simon Peyton Jones 09 May '22

09 May '22

Dear devs At the moment the INLINEABLE pragma means "capture my right-hand side, regardless of how big it is, so that it can be type-class-specialised, including in other modules". But it *also *says "feel free to inline me". Some users (eg Gergo) want to say NOINLINE on some functions. But for these they'd still like to generate type-class-specialised versions. After all, if we aren't going to inline them, specialising is the next best thing. But we have no way to say both "specialise me" and "don't inline me", because you can't say both INLINEABLE and NOINLINE. (That would look silly.) I think we should probably just bite the bullet and add a SPECIALISABLE pragma, *orthogonal to INLINE/NOINLNE*, which say "capture my right-hand side, regardless of how big it is, so that it can be type-class-specialised, including in other modules". It behaves exactly like INLINEABLE except that you can specify it along with INLINE/NOINLINE. Any thoughts? Do you think this needs a GHC proposal? See #21036 <https://gitlab.haskell.org/ghc/ghc/-/issues/21036#note_407930> Simon

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[ANNOUNCE] GHC 9.2.2 is not available
by Ben Gamari 05 May '22

05 May '22

The GHC developers are very happy to at announce the availability of GHC 9.2.2. Binary distributions, source distributions, and documentation are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.2.2 This release includes many bug-fixes and other improvements to 9.2.1 including: * A number of bug-fixes in the new AArch64 native code generator * Fixes ensuring that the `indexWord8ArrayAs*#` family of primops is handled correctly on platforms lacking support for unaligned memory accesses (#21015, #20987). * Improvements to the compatibility story in GHC's migration to the XDG Base Directory Specification (#20684, #20669, #20660) * Restored compatibility with Windows 7 * A new `-fcompact-unwind` flag, improving compatibility with C++ libraries on Apple Darwin (#11829) * Introduction of a new flag, `-fcheck-prim-bounds`, enabling runtime bounds checking of array primops (#20769) * Unboxing of unlifted types (#20663) * Numerous improvements in compiler performance. * Many, many others. See the [release notes] for a full list. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. Finally, thank you to Microsoft Research, GitHub, IOHK, the Zw3rk stake pool, Tweag I/O, Serokell, Equinix, SimSpace, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Moreover, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do open a [ticket][] if you see anything amiss. Happy compiling, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/ghc/9.2.2/docs/html/users_guide/9.2.2-notes.h…

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"Modularizing GHC" paper
by Sylvain Henry 04 May '22

04 May '22

Hi GHC devs, With John Ericson and Jeffrey Young we wrote a paper about the modularization of GHC. It gives a global picture for the refactorings we have been performing (c.f. e.g. #17957) and some potential future ones. Announce blog post: https://hsyl20.fr/home/posts/2022-05-03-modularizing-ghc-paper.html Paper: https://hsyl20.fr/home/files/papers/2022-ghc-modularity.pdf Discussion on Reddit: https://www.reddit.com/r/haskell/comments/uhdu4l/modularizing_ghc_paper/ We welcome any feedback, here or on reddit. Cheers, Sylvain

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