April 2024 - ghc-devs

Reinstallable - base
by Simon Peyton Jones 07 Aug '24

07 Aug '24

Dear GHC devs Given the now-agreed split between ghc-internal and base <https://github.com/haskellfoundation/tech-proposals/pull/51>, what stands in the way of a "reinstallable base"? Specifically, suppose that - GHC 9.8 comes out with base-4.9 - The CLC decides to make some change to `base`, so we get base-4.10 - Then GHC 9.10 comes out with base-4.10 I think we'd all like it if someone could use GHC 9.10 to compile a library L that depends on base-4.9 and either L doesn't work at all with base-4.10, or L's dependency bounds have not yet been adjusted to allow base-4.10. We'd like to have a version of `base`, say `base-4.9.1` that has the exact same API as `base-4.9` but works with GHC 9.10. Today, GHC 9.10 comes with a specific version of base, *and you can't change it*. The original reason for that was, I recall, that GHC knows the precise place where (say) the type Int is declared, and it'll get very confused if that data type definition moves around. But now we have `ghc-internal`, all these "things that GHC magically knows" are in `ghc-internal`, not `base`. *Hence my question: what (now) stops us making `base` behave like any other library*? That would be a big step forward, because it would mean that a newer GHC could compile old libraries against their old dependencies. (Some changes would still be difficult. If, for example, we removed Monad and replaced it with classes Mo1 and Mo2, it might be hard to simulate the old `base` with a shim. But getting 99% of the way there would still be fantastic.) Simon

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Call for Talks: Haskell Implementors' Workshop 2024
by Matthew Pickering 08 Jul '24

08 Jul '24

``` ACM SIGPLAN Haskell Implementors' Workshop https://icfp24.sigplan.org/home/hiw-2024 Milan, Italy, September 2, 2024 Co-located with ICFP 2024 https://icfp24.sigplan.org/ ``` ## Important dates * Deadline: July 19, 2024 (AoE) * Notification: August 2, 2024 * Workshop: September 2, 2024 The 16th Haskell Implementors’ Workshop is to be held alongside ICFP 2024 this year in Milan. It is a forum for people involved in the design and development of Haskell implementations, tools, libraries, and supporting infrastructure to share their work and to discuss future directions and collaborations with others. Talks and/or demos are proposed by submitting an abstract, and selected by a small program committee. There will be no published proceedings. The workshop will be informal and interactive, with open spaces in the timetable and room for ad-hoc discussion, demos, and lightning talks. ## Scope and Target Audience It is important to distinguish the Haskell Implementors’ Workshop from the Haskell Symposium which is also co-located with ICFP 2024. The Haskell Symposium is for the publication of Haskell-related research. In contrast, the Haskell Implementors’ Workshop will have no proceedings – although we will aim to make talk videos, slides, and presented data available with the consent of the speakers. The Implementors’ Workshop is an ideal place to describe a Haskell extension, describe works-in-progress, demo a new Haskell-related tool, or even propose future lines of Haskell development. Members of the wider Haskell community are encouraged to attend the workshop – we need your feedback to keep the Haskell ecosystem thriving. Students working with Haskell are especially encouraged to share their work. The scope covers any of the following topics. There may be some topics that people feel we’ve missed, so by all means submit a proposal even if it doesn’t fit exactly into one of these buckets: * Compilation techniques * Language features and extensions * Type system implementation * Concurrency and parallelism: language design and implementation * Performance, optimization and benchmarking * Virtual machines and run-time systems * Libraries and tools for development or deployment ## Talks We invite proposals from potential speakers for talks and demonstrations. We are aiming for 20-minute talks with 5 minutes for questions and changeovers. We want to hear from people writing compilers, tools, or libraries, people with cool ideas for directions in which we should take the platform, proposals for new features to be implemented, and half-baked crazy ideas. Please submit a talk title and abstract of no more than 300 words. Submissions can be made via HotCRP at https://hiw2024.hotcrp.com until July 19 (anywhere on earth). We will also have a lightning talks session. These have been very well received in recent years, and we aim to increase the time available to them. Lightning talks should be ~7mins and are scheduled on the day of the workshop. Suggested topics for lightning talks are to present a single idea, a work-in-progress project, a problem to intrigue and perplex Haskell implementors, or simply to ask for feedback and collaborators. ## Program Committee * Matthew Pickering (Well-Typed LLP) * David Binder (University of Tübingen) * Gabriella Gonzalez (Mercury) * Sylvain Henry (IOG) * Teofil Camarasu (Tracsis) ## Contact * Matthew Pickering

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2nd Call for Papers: ACM Workshop on Functional Software Architecture [Deadline June 3]
by michael.sperber＠active-group.de 24 Apr '24

24 Apr '24

====================================================================== *** FUNARCH 2024 -- CALL FOR PAPERS *** Second ACM SIGPLAN Workshop on Functional Software Architecture - FP in the Large 6th September 2024, Milan, Italy Co-located with ICFP 2024 https://functional-architecture.org/events/funarch-2024/ ====================================================================== TIMELINE: Paper submission 3rd June 2024 Author notification 30th June 2024 Camera ready copy 18th July 2024 Workshop 6th Sept 2024 BACKGROUND: "Functional Software Architecture" refers to methods of construction and structure of large and long-lived software projects that are implemented in functional languages and released to real users, typically in industry. The goals for the workshop are: - To assemble a community interested in software architecture techniques and technologies specific to functional programming; - To identify, categorize, and document topics relevant to the field of functional software architecture; - To connect the functional programming community to the software architecture community to cross-pollinate between the two. The workshop follows on from the Functional Software Architecture open space that was held at ICFP 2022 in Slovenia. SCOPE: The workshop seeks submissions in a range of categories: - You're a member of the FP community and have thought about how to support programming in the large, for example by framing functional ideas in architectural terms or vice verse, comparing different languages in terms of their architectural capabilities, clarifying architectural roles played by formal methods, proof assistants and DSLs, or observing how functional concepts are used in other language and architecture communities. Great, submit a research paper! - You're a member of the architecture community, and have thought about how your discipline might help functional programmers, for example by applying domain-driven design, implementing hexagonal architecture, or designing self-contained systems. Excellent, submit a research paper! - You've worked on a large project using functional programming, and it's worked out well, or terribly, or a mix of both; bonus points for deriving architectural principles from your experience. Wonderful, submit an experience report! - You know a neat architectural idiom or pattern that may be useful to others developing large functional software systems. Fabulous, submit an architectural pearl! - You have something that doesn't fit the above categories, but that still relates to functional software architecture, such as something that can be written up, or that could be part of the workshop format like a panel debate or a fishbowl. Superb, submit to the open category! Research papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work, and to other languages where appropriate. Experience reports and architectural pearls need not necessarily report original research results. The key criterion for such papers is that they make a contribution from which others can benefit. It is not enough simply to describe a large software system, or to present ideas that are specific to a particular system. Open category submissions that are not intended for publication are not required to follow the formatting guidelines, and can submit in PDF, word or plain text format as preferred. Not knowing what kinds of submissions we will receive, we cannot be specific as to how they will be evaluated. However, submissions that seem likely to stimulate discussion around practices in functional architecture are encouraged. If you are unsure whether your contribution is suitable, or if you need any kind of help with your submission, please email the program chairs at <funarch2024(a)easychair.org>. Papers must be submitted by 3rd June 2024 using the EasyChair submission page: https://easychair.org/my/conference?conf=funarch2024 Formatting: submissions intended for publication must be in PDF format and follow the ACM SIGPLAN style guidelines, using the acmart format and the sigplan sub-format. Please use the review option when submitting, as this enables line numbers for easy reference in reviews. For further details, see SIGPLAN's author information: http://www.sigplan.org/Resources/Author/#acmart-format If your submission is not a research paper, please mark this using a subtitle (Experience Report, Architectural Pearl, Open Category). Length: submissions must adhere to the limits specified below. However, there is no requirement or expectation that all pages are used, and authors are encouraged to strive for brevity. Research papers 5 to 12+ pages Architectural pearls 5 to 12 pages Experience reports 3 to 6 pages Open category 1 to 6 pages Publication: The proceedings of FUNARCH 2024 will be published in the ACM Digital Library, and authors of accepted papers are required to agree to one of the standard ACM licensing options. Accepted papers must be presented at the workshop by one of the authors, but in special cases we may consider remote presentation. The official publication date is the date the papers are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work. PROGRAM CHAIRS: Mike Sperber (Active Group, Germany) Perdita Stevens (University of Edinburgh, UK) PROGRAM COMMITTEE: Annette Bieniusa (University of Kaiserslautern) Jeffrey Young (IOG) Will Crichton (Brown University) Isabella Stilkerich (Schaeffler Technologies AG) Kiko Fernandez-Reyes (Ericsson) Ryan Scott (Galois) Satnam Singh (Groq) Facundo Dominguez (Tweag) Ilya Sergey (University of Singapore) Martin Elsman (University of Copenhagen) Benjamin Pierce (University of Pennsylvania) Matthew Flatt (University of Utah) Nada Amin (Harvard University) Richard Eisenberg (Jane Street) WORKSHOP VENUE: The workshop will be co-located with the ICFP 2024 conference at the Fiera Milano Congressi, Milan, Italy.

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New registration on GHC Gitlab
by divya＠subvertising.org 19 Apr '24

19 Apr '24

Hello, I am Divya looking forward to start making some little contributions to this language community. I have been using Haskell for a few years now, and it was the reason I have been in love with functional programming. I've registered a new account on the gitlab instance with the username `divya`, may I get that verified so that I can continue further? Thank you. Regards, Divya Ranjan, Mathematics, Philosophy and Libre Software.

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Crashing in testsuite driver
by Simon Peyton Jones 19 Apr '24

19 Apr '24

Dear GHC-Devs Aargh! Suddenly I can't run the testsuite on HEAD. See below. I'm on Ubuntu, and have run 'apt update; apt upgrade', so I'm up to date. This is totally stalling me. Can anyone help? Thanks! Simon hadrian/build -j15 test --skip=_build/stage0/** --skip=_build/stage1/** --docs=no-haddocks --only=T12461 Resolving dependencies... Up to date ]0;Starting... | Run Testsuite GetExtraDeps: none Command line: /usr/bin/python3 -Wdefault testsuite/driver/runtests.py --rootdir=testsuite/tests --rootdir=libraries/binary/tests --rootdir=libraries/bytestring/tests --rootdir=libraries/directory/tests --rootdir=libraries/exceptions/tests --rootdir=libraries/filepath/tests --rootdir=libraries/ghc-heap/tests --rootdir=libraries/os-string/tests --rootdir=libraries/text/tests --rootdir=libraries/array/tests --rootdir=libraries/base/tests --rootdir=libraries/deepseq/tests --rootdir=libraries/exceptions/tests --rootdir=libraries/ghc-compact/tests --rootdir=libraries/ghc-prim/tests --rootdir=libraries/haskeline/tests --rootdir=libraries/pretty/tests --rootdir=libraries/template-haskell/tests --rootdir=libraries/stm/tests --rootdir=libraries/unix/tests --top /home/simonpj/code/HEAD-23/testsuite -e windows=False -e darwin=False -e config.local=False -e config.cleanup=True -e config.accept=False -e config.accept_platform=False -e config.accept_os=False -e 'config.exeext='\'''\''' -e config.compiler_debugged=False -e config.debug_rts=False -e ghc_with_native_codegen=True -e config.have_ncg=True -e config.have_llvm=False -e config.compiler_profiled=False -e config.have_RTS_linker=True -e 'config.package_conf_cache_file="/home/simonpj/code/HEAD-23/_build/stage1/lib/package.conf.d/package.cache"' -e 'config.libdir="/home/simonpj/code/HEAD-23/_build/stage1/lib"' -e config.have_interp=True -e config.unregisterised=False -e config.tables_next_to_code=True -e 'ghc_compiler_always_flags='\'' -dcore-lint -dstg-lint -dcmm-lint -no-user-package-db -fno-dump-with-ways -fprint-error-index-links=never -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics-color=never -fno-diagnostics-show-caret -Werror=compat -dno-debug-output'\''' -e ghc_with_dynamic_rts=True -e config.ghc_with_threaded_rts=True -e config.have_fast_bignum=True -e target_with_smp=True -e config.ghc_dynamic=True -e config.leading_underscore=False -e 'config.wordsize="64"' -e 'config.os="linux"' -e 'config.arch="x86_64"' -e 'config.platform="x86_64-unknown-linux"' -e config.stage=2 --config gs=gs --config 'timeout_prog="/home/simonpj/code/HEAD-23/_build/testsuite/timeout/install-inplace/bin/timeout"' --config stats_files_dir=_build/stage1/haddock-timing-files --threads=15 --config-file=testsuite/config/ghc --only=T12461 -e config.speed=1 --summary-file=testsuite_summary.txt --verbose=2 --config 'compiler="/home/simonpj/code/HEAD-23/_build/stage1/bin/ghc"' --config 'ghc_pkg="/home/simonpj/code/HEAD-23/_build/stage1/bin/ghc-pkg"' --config haddock= --config 'hp2ps="/home/simonpj/code/HEAD-23/_build/stage1/bin/hp2ps"' --config 'hpc="/home/simonpj/code/HEAD-23/_build/stage1/bin/hpc"' -e config.in_tree_compiler=True --only-report-hadrian-deps /tmp/extra-file-60780399662884-22612-0 ===> Command failed with error code: 1 /usr/lib/python3/dist-packages/apport/report.py:13: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses import fnmatch, glob, traceback, errno, sys, atexit, imp, stat Traceback (most recent call last): File "testsuite/driver/runtests.py", line 470, in <module> framework_fail(name, None, 'test not found') File "/home/simonpj/code/HEAD-23/testsuite/driver/testlib.py", line 1537, in framework_fail directory = re.sub(r'^\.[/\\]', '', str(opts.testdir)) File "/home/simonpj/code/HEAD-23/testsuite/driver/testglobals.py", line 467, in testdir raise Exception('testdir not initialized') Exception: testdir not initialized Timeout is 300 Known ways: hpc, prof, normal_h, prof_hc_hb, prof_hb, prof_hd, prof_hy, prof_hr, sanity, threaded1_ls, threaded2_hT, threaded2_sanity, debug_numa, llvm, debugllvm, profllvm, profoptllvm, profthreadedllvm, debug, ghci-ext, ghci-ext-prof, ext-interp, nonmoving, nonmoving_thr, nonmoving_thr_sanity, nonmoving_thr_ghc, compacting_gc Run ways: normal, optasm, ghci, ghci-opt, threaded1, threaded2, dyn, hpc Compile ways: normal, optasm, hpc Allowing performance changes in: Found 591 .T files... Beginning test run at Fri Apr 19 11:47:08 2024 Detected CPU features: {'flags', 'fma', 'mmx', 'smap', 'sse4_2', 'abm', 'sep', 'tsc_reliable', 'syscall', 'ssbd', 'hypervisor', 'rdtscp', 'sse4_1', 'ssse3', 'extd_apicid', 'ibpb', 'avx', 'sse', 'constant_tsc', 'cpuid', 'avx2', 'fxsr_opt', 'rdrand', 'nonstop_tsc', 'cmov', 'osvw', 'rep_good', 'misalignsse', 'pat', 'ht', 'mmxext', 'mca', 'lahf_lm', 'pae', 'fsgsbase', 'f16c', 'pclmulqdq', 'clwb', 'mtrr', 'popcnt', 'aes', 'topoext', 'sse4a', 'vme', 'clflush', 'cr8_legacy', 'de', 'xsaveerptr', 'fxsr', 'cx16', 'arat', 'movbe', 'sse3', 'nx', 'apic', '3dnowprefetch', 'rdseed', 'sha_ni', 'msr', 'lm', 'pge', 'mce', 'sse2', 'xsave', 'bmi2', 'clzero', 'vmmcall', 'cmp_legacy', 'tsc', 'clflushopt', 'umip', ':', 'fpu', 'virt_ssbd', 'bmi1', 'xsavec', 'pdpe1gb', 'stibp', 'xgetbv1', 'pse36', 'nopl', 'adx', 'cx8', 'pse', 'smep', 'xsaveopt', 'rdpid'} Found CPU features: flags fma mmx smap sse4_2 abm sep tsc_reliable syscall ssbd hypervisor rdtscp sse4_1 ssse3 extd_apicid ibpb avx sse constant_tsc cpuid avx2 fxsr_opt rdrand nonstop_tsc cmov osvw rep_good misalignsse pat ht mmxext mca lahf_lm pae fsgsbase f16c pclmulqdq clwb mtrr popcnt aes topoext sse4a vme clflush cr8_legacy de xsaveerptr fxsr cx16 arat movbe sse3 nx apic 3dnowprefetch rdseed sha_ni msr lm pge mce sse2 xsave bmi2 clzero vmmcall cmp_legacy tsc clflushopt umip : fpu virt_ssbd bmi1 xsavec pdpe1gb stibp xgetbv1 pse36 nopl adx cx8 pse smep xsaveopt rdpid ]0;Finished in 1.70s Command failed Build failed. make: *** [/home/simonpj/code/Makefile-spj:35: tests-only] Error 1 simonpj@LHR-WD-22561:~/code/HEAD-23$

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[ANNOUNCE] GHC 9.6.5 is now available
by Zubin Duggal 16 Apr '24

16 Apr '24

The GHC developers are happy to announce the availability of GHC 9.6.5. Binary distributions, source distributions, and documentation are available on the [release page](https://www.haskell.org/ghc/download_ghc_9_6_5.html). GHC Blog Post: https://www.haskell.org/ghc/blog/20240416-ghc-9.6.5-released.html This release is primarily a bugfix release addressing some issues found in the 9.6 series. These include: * Bumping the bundled `process` library to 1.6.19.0 to avoid a potential [command injection vulnerability] on Windows for clients of this library. This isn't known to affect GHC itself, but allows users who depend on the installed version of the `process` to avoid the issue. * Fixing a bug resulting in the distributed ``hsc2hs`` wrapper using flags from the compiler build environment (#24050). * Disabling the `-fasm-shortcutting` optimisation with `-O2` as it is known to result in unsoundess and incorrect runtime results in some cases (#24507). * Ensuring we take ``LDFLAGS`` into account when configuring a linker (#24565). * Fixing a bug arising from incorrect parsing of paths containing spaces in the settings file (#24265). * 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/9.6.5/docs/users_guide/9.6.5-notes.html [command injection vulnerability]: https://github.com/haskell/security-advisories/blob/main/advisories/hackage…

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[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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Request for approval of my GHC GitLab Account
by Hiroki Tokunaga 10 Apr '24

10 Apr '24

Dear GHC administrators, I am Hiroki Tokunaga, and I am interested in joining the development of GHC and other Haskell tools. For this, I would like to get your approval for my GitLab account (username: HirokiTokunaga). Thank you for reading this e-mail. I look forward to your response. Sincerely, Hiroki Tokunaga

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Request for Approval of GHC GitLab Account
by chenxi li 07 Apr '24

07 Apr '24

Dear GHC Administrators, My name is Chenxi Li and I am interested in contributing to the GHC project. I have read through the contributing guidelines and am looking forward to joining the GHC community. My GHC GitLab username is *ayanamists(a)gmail.com <ayanamists(a)gmail.com>*. Due to the platform's anti-spam policy, I require your approval to begin contributing. Thank you for your time and consideration. I look forward to your response. Best regards, Chenxi Li

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Missing dependencies
by Simon Peyton Jones 03 Apr '24

03 Apr '24

Friends My work has stalled because of https://gitlab.haskell.org/ghc/ghc/-/issues/24436 E.g. see https://gitlab.haskell.org/ghc/ghc/-/merge_requests/11492 which fails to build. Does anyone know a good workaround? Thanks! Simon

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