# Uncategorized

**URL:** https://discourse.haskell.org/c/uncategorized/1.md?no_subcategories=false&page=3

[Latest](https://discourse.haskell.org/latest.md) · [Categories](https://discourse.haskell.org/categories.md) · [Tags](https://discourse.haskell.org/tags.md)

**Page:** 4

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## [Breaking changes in time 1.15 / GHC 9.14](https://discourse.haskell.org/t/breaking-changes-in-time-1-15-ghc-9-14/13711)

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**Author:** [@m4dc4p](https://discourse.haskell.org/u/m4dc4p)\
**Replies:** 5\
**Last updated:** [February 22, 2026, 4:34pm UTC](https://discourse.haskell.org/t/breaking-changes-in-time-1-15-ghc-9-14/13711 "2026-02-22T16:34:25Z")

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time 1.15, which ships with GHC 9.14, introduces three new pattern constructors, exported from Data.Time and Data.Time.Clock: Hours, Minutes and Seconds. This makes it hard to maintain source compatability across GHC 9.…

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## [\[ANN\] kdl-hs 1.0.0 released with v2 support](https://discourse.haskell.org/t/ann-kdl-hs-1-0-0-released-with-v2-support/13712)

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**Author:** [@brandonchinn178](https://discourse.haskell.org/u/brandonchinn178)\
**Replies:** 0\
**Last updated:** [February 21, 2026, 10:23pm UTC](https://discourse.haskell.org/t/ann-kdl-hs-1-0-0-released-with-v2-support/13712 "2026-02-21T22:23:18Z")

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kdl-hs is a parser for the KDL configuration language, providing both monadic and arrow-based decoding functionality. v1.0.0 reimplements the parser to be v2 compliant. The parser now preserves format information, so KD…

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## [Haskell wlroots bindings](https://discourse.haskell.org/t/haskell-wlroots-bindings/8426)

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**Author:** [@bradrn](https://discourse.haskell.org/u/bradrn)\
**Replies:** 128\
**Last updated:** [February 18, 2026, 9:26am UTC](https://discourse.haskell.org/t/haskell-wlroots-bindings/8426 "2026-02-18T09:26:11Z")

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This is split off from the Waymonad thread in the hopes of coordinating some new bindings for wlroots. Starting off with my thoughts on design questions from @anarchymatt: I have no idea. I suspect it depends on how c…

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## [Reflecting Code to Syntax (with Arrows)](https://discourse.haskell.org/t/reflecting-code-to-syntax-with-arrows/13646)

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**Author:** [@tomjaguarpaw](https://discourse.haskell.org/u/tomjaguarpaw)\
**Replies:** 26\
**Last updated:** [February 17, 2026, 3:46pm UTC](https://discourse.haskell.org/t/reflecting-code-to-syntax-with-arrows/13646 "2026-02-17T15:46:19Z")

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Not sure what you mean exactly, but Opaleye uses arrows (or monads) to represent database queries that are “serialised” to SQL so maybe that’s evidence that what you think is an impediment is not actually one?

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## [Hoogle@stackage down for just me, or?](https://discourse.haskell.org/t/hoogle-stackage-down-for-just-me-or/13668)

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**Author:** [@develop7](https://discourse.haskell.org/u/develop7)\
**Replies:** 5\
**Last updated:** [February 13, 2026, 9:55am UTC](https://discourse.haskell.org/t/hoogle-stackage-down-for-just-me-or/13668 "2026-02-13T09:55:35Z")

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Is it just me or subj is non-functional? Hoogle database not available :: Stackage Server replies with “Hoogle database is not available” for every LTS snapshot

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## [Improving Machine Arithmetic](https://discourse.haskell.org/t/improving-machine-arithmetic/13602)

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**Author:** [@mniip](https://discourse.haskell.org/u/mniip)\
**Replies:** 19\
**Last updated:** [February 3, 2026, 7:12am UTC](https://discourse.haskell.org/t/improving-machine-arithmetic/13602 "2026-02-03T07:12:02Z")

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Every once in a while I set out to write some code that involves e.g. some nontrivial index arithmetic, and I find the available toolbox for machine arithmetic clearly lacking. To be specific, I don’t mean any advanced n…

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## [\[GSoC 2026\] Final call for ideas](https://discourse.haskell.org/t/gsoc-2026-final-call-for-ideas/13614)

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**Author:** [@aaron-allen](https://discourse.haskell.org/u/aaron-allen)\
**Replies:** 1\
**Last updated:** [January 30, 2026, 8:33pm UTC](https://discourse.haskell.org/t/gsoc-2026-final-call-for-ideas/13614 "2026-01-30T20:33:28Z")

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In case you missed it, Haskell will be applying for Google Summer of Code 2026. In order to have a good chance of being accepted, we need a healthy list of projects that prospective contributors can choose from. We’re ho…

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## [Hackage errors: invalid hash S-5170 InvalidChunkHeaders](https://discourse.haskell.org/t/hackage-errors-invalid-hash-s-5170-invalidchunkheaders/12935)

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**Author:** [@claudio](https://discourse.haskell.org/u/claudio)\
**Replies:** 18\
**Last updated:** [January 30, 2026, 1:15pm UTC](https://discourse.haskell.org/t/hackage-errors-invalid-hash-s-5170-invalidchunkheaders/12935 "2026-01-30T13:15:42Z")

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Hi. We are constantly seeing two different errors on CI and I really would like to understand and fix them. First one is this: Selected mirror https://hackage.haskell.org/ Downloading root Waiting to acquire cache loc…

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## [Haskellers at FOSDEM 2026](https://discourse.haskell.org/t/haskellers-at-fosdem-2026/13616)

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**Author:** [@chreekat](https://discourse.haskell.org/u/chreekat)\
**Replies:** 0\
**Last updated:** [January 29, 2026, 2:17pm UTC](https://discourse.haskell.org/t/haskellers-at-fosdem-2026/13616 "2026-01-29T14:17:24Z")

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Anybody else gonna be there? If there’s enough of us Haskellers, maybe we could arrange an impromptu get-together of some kind.

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## [Local LLMs thread](https://discourse.haskell.org/t/local-llms-thread/13609)

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**Author:** [@chrisdone](https://discourse.haskell.org/u/chrisdone)\
**Replies:** 3\
**Last updated:** [January 28, 2026, 4:24pm UTC](https://discourse.haskell.org/t/local-llms-thread/13609 "2026-01-28T16:24:31Z")

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There’s another thread which appears mainly to be about paying rent on a big tech LLM provider. The models are big and powerful. That’s alright but I thought in this thread there could be some chat about local models, i…

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## [Evolving the Stack Annotations API to include Source Locations](https://discourse.haskell.org/t/evolving-the-stack-annotations-api-to-include-source-locations/13598)

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**Author:** [@fendor](https://discourse.haskell.org/u/fendor)\
**Replies:** 4\
**Last updated:** [January 28, 2026, 10:24am UTC](https://discourse.haskell.org/t/evolving-the-stack-annotations-api-to-include-source-locations/13598 "2026-01-28T10:24:12Z")

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Stack Annotations are a new feature in GHC-9.14 which allow you to push arbitrary Haskell values to the RTS callstack. The annotations are rendered in backtraces in order to provide additional context for exceptions. W…

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## [\[Back up\] Haskell.org subdomains down: gitlab, hoogle, wiki, downloads](https://discourse.haskell.org/t/back-up-haskell-org-subdomains-down-gitlab-hoogle-wiki-downloads/13337)

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**Author:** [@Jappie](https://discourse.haskell.org/u/Jappie)\
**Replies:** 9\
**Last updated:** [January 24, 2026, 1:38pm UTC](https://discourse.haskell.org/t/back-up-haskell-org-subdomains-down-gitlab-hoogle-wiki-downloads/13337 "2026-01-24T13:38:29Z")

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leana and I tried cloning ghc just now and it just fails on the submodule, furthermore cloning from the github mirror doesn’t work either because all submodules point to gitlab :sweat\_smile:

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## [Seeking Open Source & Real-World Haskell Experience. Eager to Learn by Contributing (Docs, Tests, Small Fixes)](https://discourse.haskell.org/t/seeking-open-source-real-world-haskell-experience-eager-to-learn-by-contributing-docs-tests-small-fixes/13558)

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**Author:** [@lbauchwitz](https://discourse.haskell.org/u/lbauchwitz)\
**Replies:** 11\
**Last updated:** [January 20, 2026, 10:49am UTC](https://discourse.haskell.org/t/seeking-open-source-real-world-haskell-experience-eager-to-learn-by-contributing-docs-tests-small-fixes/13558 "2026-01-20T10:49:25Z")

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Hello I’m a seasoned Systems Administrator and Developer with over 20 years of experience in infrastructure and software, and I’m now making a deliberate pivot toward Haskell development. About three years ago, I compl…

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## [QualifiedDo + ApplicativeDo still requires \>\>=?](https://discourse.haskell.org/t/qualifieddo-applicativedo-still-requires/13491)

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**Author:** [@brandonchinn178](https://discourse.haskell.org/u/brandonchinn178)\
**Replies:** 8\
**Last updated:** [January 5, 2026, 11:25pm UTC](https://discourse.haskell.org/t/qualifieddo-applicativedo-still-requires/13491 "2026-01-05T23:25:36Z")

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According to the QualifiedDo docs, a qualified-do block with -XApplicativeDo enabled should translate to a pure applicative expression: M.do { (x1 \<- u1 | … | xn \<- un); M.return e } = (\\x1 … xn -\> e) \`M.fmap\` u1 M.\<\*…

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## [\[GSoC 2026\] Call for Ideas](https://discourse.haskell.org/t/gsoc-2026-call-for-ideas/13479)

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**Author:** [@aaron-allen](https://discourse.haskell.org/u/aaron-allen)\
**Replies:** 0\
**Last updated:** [January 1, 2026, 6:15pm UTC](https://discourse.haskell.org/t/gsoc-2026-call-for-ideas/13479 "2026-01-01T18:15:53Z")

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Google Summer of Code is a long-running program that supports Open Source projects. Haskell has taken part in this program almost since its inception! It allows newcomers to open source to contribute to projects for a s…

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## [\[Haskell Cryptography Group\] A vulnerability in libsodium's validation of ed25519 elliptic curve points: You are likely not affected](https://discourse.haskell.org/t/haskell-cryptography-group-a-vulnerability-in-libsodiums-validation-of-ed25519-elliptic-curve-points-you-are-likely-not-affected/13470)

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**Author:** [@Kleidukos](https://discourse.haskell.org/u/Kleidukos)\
**Replies:** 0\
**Last updated:** [December 31, 2025, 12:11pm UTC](https://discourse.haskell.org/t/haskell-cryptography-group-a-vulnerability-in-libsodiums-validation-of-ed25519-elliptic-curve-points-you-are-likely-not-affected/13470 "2025-12-31T12:11:54Z")

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Hi everyone, Libsodium’s author Frank Denis has found a missing check for validating elliptic curve points in a low-level function not exposed by libsodium-bindings. However it seems important to communicate on this iss…

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## [Idea: record syntax for type parameters](https://discourse.haskell.org/t/idea-record-syntax-for-type-parameters/12879)

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**Author:** [@fpringle](https://discourse.haskell.org/u/fpringle)\
**Replies:** 12\
**Last updated:** [December 30, 2025, 12:52am UTC](https://discourse.haskell.org/t/idea-record-syntax-for-type-parameters/12879 "2025-12-30T00:52:56Z")

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Intro I’ve noticed a common problem cropping up in some of the projects I’ve worked on, regarding heavily-parameterised datatypes with several type aliases for different use-cases. I’ve also had the concept of a solutio…

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## [Haskell/GHC ecosystem](https://discourse.haskell.org/t/haskell-ghc-ecosystem/13436)

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**Author:** [@augustss](https://discourse.haskell.org/u/augustss)\
**Replies:** 9\
**Last updated:** [December 28, 2025, 12:43am UTC](https://discourse.haskell.org/t/haskell-ghc-ecosystem/13436 "2025-12-28T00:43:26Z")

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Is the Haskell Foundation at all interested in doing work not related to GHC? It’s fine if the answer is no, but it would be interesting to know.

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## [The Subtle Footgun of TVar (Map \_ \_)](https://discourse.haskell.org/t/the-subtle-footgun-of-tvar-map/13429)

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**Author:** [@parsonsmatt](https://discourse.haskell.org/u/parsonsmatt)\
**Replies:** 8\
**Last updated:** [December 22, 2025, 9:19pm UTC](https://discourse.haskell.org/t/the-subtle-footgun-of-tvar-map/13429 "2025-12-22T21:19:37Z")

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I’ve made massive improvements in concurrency performance several times recently with a really easy and mechanical change, so I figure it’s time to share this and try to popularize the idea. Major kudos to Nikita Volk…

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## [A lighter-weight alternative to runhaskell for quick scripts](https://discourse.haskell.org/t/a-lighter-weight-alternative-to-runhaskell-for-quick-scripts/13326)

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**Author:** [@mchav](https://discourse.haskell.org/u/mchav)\
**Replies:** 5\
**Last updated:** [December 17, 2025, 3:48pm UTC](https://discourse.haskell.org/t/a-lighter-weight-alternative-to-runhaskell-for-quick-scripts/13326 "2025-12-17T15:48:05Z")

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I labelled this as uncategorized as it’s somewhere between a question and a show-and-tell. I was helping someone use knitr to embed and run Haskell code in Quarto. The knitr code looks like this: knitr::knit\_engines$s…

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## [Arm64 binaries too large?](https://discourse.haskell.org/t/arm64-binaries-too-large/13416)

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**Author:** [@brandonchinn178](https://discourse.haskell.org/u/brandonchinn178)\
**Replies:** 1\
**Last updated:** [December 15, 2025, 9:41pm UTC](https://discourse.haskell.org/t/arm64-binaries-too-large/13416 "2025-12-15T21:41:40Z")

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The arm64 binaries are ~10x larger than the x86\_64 binaries at Release v1.0.0 · brandonchinn178/xreferee · GitHub. From AI, I tried adding --enable-split-sections and ghc-options: -optl-s if os(linux) ghc-optio…

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## [GHC Gitlab Outage](https://discourse.haskell.org/t/ghc-gitlab-outage/13410)

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**Author:** [@mpscholten](https://discourse.haskell.org/u/mpscholten)\
**Replies:** 3\
**Last updated:** [December 14, 2025, 5:39pm UTC](https://discourse.haskell.org/t/ghc-gitlab-outage/13410 "2025-12-14T17:39:31Z")

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It seems https://gitlab.haskell.org/ghc/ghc is down. Any updates when it will be up again?

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## [Fantastic dependency graph vizualizer and writeup](https://discourse.haskell.org/t/fantastic-dependency-graph-vizualizer-and-writeup/13379)

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**Author:** [@sclv](https://discourse.haskell.org/u/sclv)\
**Replies:** 2\
**Last updated:** [December 12, 2025, 9:27am UTC](https://discourse.haskell.org/t/fantastic-dependency-graph-vizualizer-and-writeup/13379 "2025-12-12T09:27:28Z")

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Someone took the famous xkcd comic about dependency trees, hit it with some computer science and created a great toy. Would love someone with free time to extend the tool to run on hackage packages as well!

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## [GHC's profiling tools: overview](https://discourse.haskell.org/t/ghcs-profiling-tools-overview/13380)

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**Author:** [@simonpj](https://discourse.haskell.org/u/simonpj)\
**Replies:** 10\
**Last updated:** [December 10, 2025, 2:23pm UTC](https://discourse.haskell.org/t/ghcs-profiling-tools-overview/13380 "2025-12-10T14:23:11Z")

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I regularly find myself looking for an overview of the many profiling tools that GHC offers, but I can never find one! So I have started this wiki page as a kind of “contents list” or set of bookmarks. I don’t want to…

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## [Proposal: An issue tracker for better error messages](https://discourse.haskell.org/t/proposal-an-issue-tracker-for-better-error-messages/2498)

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**Author:** [@rae](https://discourse.haskell.org/u/rae)\
**Replies:** 26\
**Last updated:** [December 7, 2025, 9:23pm UTC](https://discourse.haskell.org/t/proposal-an-issue-tracker-for-better-error-messages/2498 "2025-12-07T21:23:10Z")

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Over the years, many have groused about the quality of GHC’s error messages. While quality of error messages is, actually, a major driver of the design and implementation of GHC, many users are still left unsatisfied. @k…

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## [Would it be possible to guarantee specialization/inlining functions based on the callee (as a plugin maybe)?](https://discourse.haskell.org/t/would-it-be-possible-to-guarantee-specialization-inlining-functions-based-on-the-callee-as-a-plugin-maybe/13360)

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**Author:** [@LeanderK](https://discourse.haskell.org/u/LeanderK)\
**Replies:** 15\
**Last updated:** [December 7, 2025, 6:05am UTC](https://discourse.haskell.org/t/would-it-be-possible-to-guarantee-specialization-inlining-functions-based-on-the-callee-as-a-plugin-maybe/13360 "2025-12-07T06:05:42Z")

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I usually work with ML/Numerical Algorithms and haskell is more of a hobby. One thing that’s important for haskell to have speedy numerical algorithms is inlining/specialization for the basic numerical types. So I wonder…

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## [GHC API: value for GHC.targetUnitId (solved!)](https://discourse.haskell.org/t/ghc-api-value-for-ghc-targetunitid-solved/13371)

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**Author:** [@elaforge](https://discourse.haskell.org/u/elaforge)\
**Replies:** 0\
**Last updated:** [December 7, 2025, 2:39am UTC](https://discourse.haskell.org/t/ghc-api-value-for-ghc-targetunitid-solved/13371 "2025-12-07T02:39:27Z")

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I’ve just been upgrading from ghc 9.2 to 9.6 and as usual, the hardest part is porting to the new GHC API. I’ve been able to figure out most of it, except I need to GHC.setTargets $ map make\_target toplevel\_modules wher…

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## [GHC musl docker manifests: Base image updated to alpine:3.23](https://discourse.haskell.org/t/ghc-musl-docker-manifests-base-image-updated-to-alpine-3-23/13370)

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**Author:** [@benz0li](https://discourse.haskell.org/u/benz0li)\
**Replies:** 0\
**Last updated:** [December 6, 2025, 4:05pm UTC](https://discourse.haskell.org/t/ghc-musl-docker-manifests-base-image-updated-to-alpine-3-23/13370 "2025-12-06T16:05:34Z")

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The following GHC musl docker manifests have been updated to alpine:3.23: glcr.b-data.ch/ghc/ghc-musl:9.12.2 glcr.b-data.ch/ghc/ghc-musl:9.12.2-int-native glcr.b-data.ch/ghc/ghc-musl:9.10.3 glcr.b-data.ch/ghc/ghc-musl:…

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## [RFC: Introduce a serialisable bytecode format and corresponding "bytecode" way](https://discourse.haskell.org/t/rfc-introduce-a-serialisable-bytecode-format-and-corresponding-bytecode-way/12678)

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**Author:** [@mpickering](https://discourse.haskell.org/u/mpickering)\
**Replies:** 4\
**Last updated:** [November 24, 2025, 10:35am UTC](https://discourse.haskell.org/t/rfc-introduce-a-serialisable-bytecode-format-and-corresponding-bytecode-way/12678 "2025-11-24T10:35:51Z")

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We are planning on adding a new “bytecode” way, to enable the persisting and packaging of bytecode artifacts. At this stage it would be useful to gather feedback from any interested parties on the proposed interface for …

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## [Share useful GHC plugins](https://discourse.haskell.org/t/share-useful-ghc-plugins/13305)

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**Author:** [@ashokkimmel](https://discourse.haskell.org/u/ashokkimmel)\
**Replies:** 7\
**Last updated:** [November 23, 2025, 10:07am UTC](https://discourse.haskell.org/t/share-useful-ghc-plugins/13305 "2025-11-23T10:07:03Z")

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I know of a few ghc plugins: norecursion: Allows for making recursion useful, avoiding recursion bugs. ghc-typelits-normalize Allows for making Type level typelet: Allows type level let monadic-bang: Allows for idris…

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