- ghc-devs - Haskell.org

use Hadrian to see if compiler compiles?
by Norman Ramsey 02 Feb '22

02 Feb '22

I'm currently doing some refactoring of the GHC sources, which involves moving definitions between modules. As a sanity check I want to compile often, so if I've broken anything (or have inadvertently created circular imports) I can find out quickly. I'm currently using ./hadrian/build -j but I really don't need to build libraries or a stage 2 compiler. I tried looking over `./hadrian/build --help`, but I'm not confident that I understand what's there. My best guess is ./hadrian/build -j stage0:lib:ghc Would that accomplish my goal? Norman

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White space in CI
by Simon Peyton Jones 01 Feb '22

01 Feb '22

Devs As you'll see from this pipeline record https://gitlab.haskell.org/ghc/ghc/-/merge_requests/7105/pipelines CI consistently fails once a single commit has trailing whitespace, even if it is fixed in a subsequent commit - dce2054d <https://gitlab.haskell.org/ghc/ghc/-/commit/dce2054d44ea60bdde6409050284fbb…> introduced trailing whitespace - 6411223c <https://gitlab.haskell.org/ghc/ghc/-/commit/6411223cd3977c92d01b09b55a455d8…> removed it again. - but all subsequent pipelines fail This came as a big surprise. It doesn't make sense to lint each individual commit. Let's just lint the final version! (I will squash them in due course, but I didn't want to lose my work-in-progress history.) Simon

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Re: downloading ghc head version
by Matthew Pickering 01 Feb '22

01 Feb '22

Right, it appears the problem was we stopped producing the deb9 bindists due to deb9 being EOL. https://gitlab.haskell.org/ghc/ghc/-/commit/871ce2a300ed35639a39a86f4c85fbc… Is your problem sorted now? Matt On Tue, Feb 1, 2022 at 12:09 AM Harendra Kumar <harendra.kumar(a)gmail.com> wrote: > > I replaced deb9 with deb10 in the URL that ghcup install was using > earlier in the CI and it seems to work. The following command > installed ghc successfully: > > $ ghcup install ghc -u > https://gitlab.haskell.org/ghc/ghc/-/jobs/artifacts/master/raw/ghc-x86_64-d… > head > $ ghc-head --version > The Glorious Glasgow Haskell Compilation System, version 9.3.20220130 > > Maybe the deb9 build has been retired now? It worked once in our CI a > few days and then never worked. > > -harendra > > On Tue, 1 Feb 2022 at 05:24, Harendra Kumar <harendra.kumar(a)gmail.com> wrote: > > > > Ah, nice. That looks like a useful repo. Thanks! > > > > I tried the nix expression: > > > > nix run -f https://github.com/mpickering/ghc-artefact-nix/archive/master.tar.gz > > ghcHEAD > > > > on my debian linux, but it is trying to download the fedora tar from > > https://gitlab.haskell.org/ghc/ghc/-/jobs/artifacts/master/raw/ghc-x86_64-f… > > . ghc-head-from.sh also downloads from the same link. Is it supposed > > to work on debian as well? The nix expression as well as > > ghc-head-from.sh finally failed with the followinf error on my > > machine: > > > > utils/ghc-cabal/dist-install/build/tmp/ghc-cabal: error while loading > > shared libraries: libstdc++.so.6: cannot open shared object file: No > > such file or directory > > > > I looked at https://github.com/mpickering/ghc-artefact-nix/blob/master/gitlab-artifact.…, > > but it does not seem to have a debian x86_64 config. > > > > -harendra > > > > On Tue, 1 Feb 2022 at 05:00, Matthew Pickering > > <matthewtpickering(a)gmail.com> wrote: > > > > > > I will look tomorrow but see where ghc-head-from gets the bindist from > > > > > > https://github.com/mpickering/ghc-artefact-nix/blob/master/ghc-head-from.sh > > > > > > On Mon, Jan 31, 2022 at 10:43 PM Harendra Kumar > > > <harendra.kumar(a)gmail.com> wrote: > > > > > > > > It seems the latest artifacts download link > > > > (https://gitlab.haskell.org/ghc/ghc/-/jobs/artifacts/...) at GHC > > > > gitlab is not working. > > > > > > > > If this is not the right place to ask this, can someone point me to > > > > the right place? > > > > > > > > -harendra > > > > > > > > On Wed, 26 Jan 2022 at 18:38, Harendra Kumar <harendra.kumar(a)gmail.com> wrote: > > > > > > > > > > Hi, > > > > > > > > > > I am trying to set up a CI for ghc head version. I am not sure what is > > > > > the official supported method to install a nightly/head version of > > > > > GHC. haskell/actions/setup on github seems to support it via ghcup. > > > > > But it almost always fails, I saw it succeeding once till now. It > > > > > tries to download it from the following URL, but fails with 404 not > > > > > found: > > > > > > > > > > downloading: https://gitlab.haskell.org/ghc/ghc/-/jobs/artifacts/master/raw/ghc-x86_64-d… > > > > > > > > > > I tried this link in the browser and I get the same error. Is that the > > > > > right way to install it? If not, can someone suggest a reliable way to > > > > > get the head version, other than building it myself? > > > > > > > > > > Thanks, > > > > > Harendra > > > > _______________________________________________ > > > > ghc-devs mailing list > > > > ghc-devs(a)haskell.org > > > > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

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downloading ghc head version
by Harendra Kumar 01 Feb '22

01 Feb '22

Hi, I am trying to set up a CI for ghc head version. I am not sure what is the official supported method to install a nightly/head version of GHC. haskell/actions/setup on github seems to support it via ghcup. But it almost always fails, I saw it succeeding once till now. It tries to download it from the following URL, but fails with 404 not found: downloading: https://gitlab.haskell.org/ghc/ghc/-/jobs/artifacts/master/raw/ghc-x86_64-d… I tried this link in the browser and I get the same error. Is that the right way to install it? If not, can someone suggest a reliable way to get the head version, other than building it myself? Thanks, Harendra

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Request for Nominations to the GHC Steering Committee
by Joachim Breitner 29 Jan '22

29 Jan '22

Dear Haskell community, the GHC Steering committee is seeking nominations for at least two new members. The committee scrutinizes, nitpicks, improves, weights and eventually accepts or rejects proposals that extend or change the language supported by GHC and other (public-facing) aspects of GHC. Our processes are described at https://github.com/ghc-proposals/ghc-proposals which is also the GitHub repository where proposals are proposed. In particular, please have a look at the bylaws at https://github.com/ghc-proposals/ghc-proposals/blob/master/committee.rst We are looking for a member who has the ability * to understand such language extension proposals, * to find holes and missing corner cases in the specifications, * foresee the interaction with other language features and specifications, * comment constructively and improve the proposals, * judge the cost/benefit ratio and * finally come to a justifiable conclusion. We look for committee members who have some of these properties: * have substantial experience in writing Haskell applications or libraries, which they can use to inform judgements about the utility or otherwise of proposed features, * have made active contributions to the Haskell community, for some time, * have expertise in language design and implementation, in either Haskell or related languages, which they can share with us. The committee’s work requires a small, but non-trivial amount of time, especially when you are assigned a proposal for shepherding. We estimate the workload to be around 2 hours per week, and our process works best if members usually respond to technical emails within 1-2 weeks (within days is even better). Please keep that in mind if your email inbox is already overflowing. There is no shortage of people who are eager to get fancy new features into the language, both in the committee and the wider community. But each new feature imposes a cost, to implement, to learn, (particularly) through its unexpected interaction with other features. We need to strike a balance, one that encourages innovation (as GHC always has) while still making Haskell attractive for real-world production use and for teaching. We therefore explicitly invite “conservative” members of the community to join the committee. To make a nomination, please send an email to me (as the committee secretary) at mail(a)joachim-breitner.de until February 11th. I will distribute the nominations among the committee, and we will keep the nominations and our deliberations private. We explicitly encourage self-nominations. You can nominate others, but please obtain their explicit consent to do so. (We don’t want to choose someone who turns out to be unable to serve.) On behalf of the committee, Joachim Breitner -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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meaning of title of merge request on gitlab?
by Norman Ramsey 28 Jan '22

28 Jan '22

I've opened a very, very preliminary MR. The Commentary instructs me to tag it "WIP: <title>", but gitlab seems to suggest that in order to prevent it from being merged, I need "Draft: <title>". When a merge request is both WIP and Draft, how should it be titled? (The MR in question is https://gitlab.haskell.org/ghc/ghc/-/merge_requests/7442) Norman

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trouble with formatted Haddock documentation for new module
by Norman Ramsey 27 Jan '22

27 Jan '22

In a new module I'm writing for GHC, I define a record type that has a ton of named fields. Two of the fields have rather large types. Unfortunately, at least with default settings, the Haddock documentation that is well-nigh unreadable (image attached). Does anyone have a workaround? Hécate? (If it's useful, a draft of the offending module can be found at https://gitlab.haskell.org/ghc/ghc/-/blob/wip/backend-as-record/compiler/GH….) Norman

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Curiosity: What accounts for the growth in the RTS in 9.2?
by Norman Ramsey 26 Jan '22

26 Jan '22

I was chatting with a colleague who asked "How big is GHC's run-time system." In the spirit of "look and find out," I found this: nr@homedog ~/.ghcup> ls -hl **HSrts.a -rw-r--r-- 1 nr nr 8.7M Sep 27 16:13 ghc/8.10.7/lib/ghc-8.10.7/rts/libHSrts.a -rw-r--r-- 1 nr nr 8.8M Sep 27 16:36 ghc/9.0.1/lib/ghc-9.0.1/rts/libHSrts.a -rw-r--r-- 1 nr nr 11M Jan 24 15:06 ghc/9.2.1/lib/ghc-9.2.1/rts/libHSrts.a All these binaries were installed by ghcup using the default settings. Does anybody know what accounts for the big jump from 9.0 to 9.2? Norman

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any luck using "retrie" refactoring tool on GHC sources?
by Norman Ramsey 24 Jan '22

24 Jan '22

I'm trying to use the retrie refactoring tool, but I'm getting a mysterious error message: nr@homedog ~/a/g/compiler [1]> retrie --adhoc "forall x . not (backendNeedn'tLink x) == backendNeedsLink x" parseAdhocs:1:80: error: parse error on input ‘#-}’ retrie: user error (parse failed) The Tool was installed using cabal install; its github page is https://github.com/facebookincubator/retrie/#readme. Has anybody had any success using this tool on the GHC sources? I'd love a workaround, or just advice. Norman

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Not all splices are the same
by David Feuer 23 Jan '22

23 Jan '22

I've been a bit upset by the challenges Template Haskell poses for type inference. For example, (3 :: Int) == $$(...) may typecheck when $$(...) == (3 :: Int) does not. I don't imagine this problem can be solved in general, but I'm rather curious whether it might be possible to solve for "pure" splices, with types that look like forall m. Quote m => Code m a Would it be possible to get full bidirectional inference for these if they were somehow marked specially by the user? For instance, if I wrote $$$e that could mean e should be interpreted as having some type PCode a where newtype PCode a = PCode (forall m. Quote m => a)

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