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Re: Loading a typechecked module and then using it immediately as a package
by Erdi, Gergo 29 Jun '21

29 Jun '21

PUBLIC Should I? OK, I just tried calling `flushFinderCaches` after I change the home unit to `mainUnitId`, but I still get exactly the same behaviour: `findInstalledHomeModule` returns `InstalledFound` and things go downhill from there. -----Original Message----- From: Matthew Pickering <matthewtpickering(a)gmail.com> Sent: Tuesday, June 29, 2021 6:34 PM To: Erdi, Gergo <Gergo.Erdi(a)sc.com> Cc: ghc-devs(a)haskell.org Subject: [External] Re: Loading a typechecked module and then using it immediately as a package ATTENTION: This email came from an external source. Do not open attachments or click on links from unknown senders or unexpected emails. Always report suspicious emails using the Report As Phishing button in Outlook to protect the Bank and our clients. Are you clearing the FinderCache? On Tue, Jun 29, 2021 at 11:14 AM Erdi, Gergo <Gergo.Erdi(a)sc.com> wrote: > > PUBLIC > > I don't know yet what's going on, but one thing I did notice is that `findInstalledHomeModule` returns `InstalledFound` for `MyLib`, which doesn't sound right to me -- `MyLib` should come from the "fake-uid" unit, and `Test` is typechecked in the `mainUnitId`. > > -----Original Message----- > From: Erdi, Gergo > Sent: Tuesday, June 29, 2021 5:51 PM > To: Matthew Pickering <matthewtpickering(a)gmail.com> > Subject: Re: Loading a typechecked module and then using it immediately as a package > > PUBLIC > > I tried moving `MyLib.hs` into a directory different than `Test.sh`, but the error message still refers to its correct location! So this error is not guessing the file name of where `MyLib.hs` could be loaded from; instead, it seems to refer correctly to where the module (previously loaded) was. Hmm. > > -----Original Message----- > From: Matthew Pickering <matthewtpickering(a)gmail.com> > Sent: Tuesday, June 29, 2021 5:04 PM > To: Erdi, Gergo <Gergo.Erdi(a)sc.com> > Subject: [External] Re: Loading a typechecked module and then using it immediately as a package > > > Do you have a `MyLib.hs` source file? If you move that somewhere else (another folder) then things might work? > > On Tue, Jun 29, 2021 at 9:41 AM Erdi, Gergo <Gergo.Erdi(a)sc.com> wrote: > > > > PUBLIC > > > > What's weird about it is that if I print the `moduleNameProvidersMap`, I can see `MyLib` inside, and it looks no different than any other module from e.g. `ghc-prim` that I can import into `Test.hs` without any package qualification. Also, why does the error message refer to the file name `input/MyLib.hs`? Why does GHC even know that that is where it would have to be loaded from, if it weren't to be used from an already loaded package? > > > > This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries at https: //www.sc.com/en/our-locations > > Where you have a Financial Markets relationship with Standard Chartered PLC, Standard Chartered Bank and their subsidiaries (the "Group"), information on the regulatory standards we adhere to and how it may affect you can be found in our Regulatory Compliance Statement at https: //www.sc.com/rcs/ and Regulatory Compliance Disclosures at http: //www.sc.com/rcs/fm > > Insofar as this communication is not sent by the Global Research team and contains any market commentary, the market commentary has been prepared by the sales and/or trading desk of Standard Chartered Bank or its affiliate. It is not and does not constitute research material, independent research, recommendation or financial advice. Any market commentary is for information purpose only and shall not be relied on for any other purpose and is subject to the relevant disclaimers available at https: //www.sc.com/en/regulatory-disclosures/#market-disclaimer. > > Insofar as this communication is sent by the Global Research team and contains any research materials prepared by members of the team, the research material is for information purpose only and shall not be relied on for any other purpose, and is subject to the relevant disclaimers available at https: //research.sc.com/research/api/application/static/terms-and-conditions. > > Insofar as this e-mail contains the term sheet for a proposed transaction, by responding affirmatively to this e-mail, you agree that you have understood the terms and conditions in the attached term sheet and evaluated the merits and risks of the transaction. We may at times also request you to sign the term sheet to acknowledge the same. > > Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for important information with respect to derivative products. This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries at https: //www.sc.com/en/our-locations Where you have a Financial Markets relationship with Standard Chartered PLC, Standard Chartered Bank and their subsidiaries (the "Group"), information on the regulatory standards we adhere to and how it may affect you can be found in our Regulatory Compliance Statement at https: //www.sc.com/rcs/ and Regulatory Compliance Disclosures at http: //www.sc.com/rcs/fm Insofar as this communication is not sent by the Global Research team and contains any market commentary, the market commentary has been prepared by the sales and/or trading desk of Standard Chartered Bank or its affiliate. It is not and does not constitute research material, independent research, recommendation or financial advice. Any market commentary is for information purpose only and shall not be relied on for any other purpose and is subject to the relevant disclaimers available at https: //www.sc.com/en/regulatory-disclosures/#market-disclaimer. Insofar as this communication is sent by the Global Research team and contains any research materials prepared by members of the team, the research material is for information purpose only and shall not be relied on for any other purpose, and is subject to the relevant disclaimers available at https: //research.sc.com/research/api/application/static/terms-and-conditions. Insofar as this e-mail contains the term sheet for a proposed transaction, by responding affirmatively to this e-mail, you agree that you have understood the terms and conditions in the attached term sheet and evaluated the merits and risks of the transaction. We may at times also request you to sign the term sheet to acknowledge the same. Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for important information with respect to derivative products.

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RE: Loading a typechecked module and then using it immediately as a package
by Erdi, Gergo 29 Jun '21

29 Jun '21

PUBLIC I don't know yet what's going on, but one thing I did notice is that `findInstalledHomeModule` returns `InstalledFound` for `MyLib`, which doesn't sound right to me -- `MyLib` should come from the "fake-uid" unit, and `Test` is typechecked in the `mainUnitId`. -----Original Message----- From: Erdi, Gergo Sent: Tuesday, June 29, 2021 5:51 PM To: Matthew Pickering <matthewtpickering(a)gmail.com> Subject: Re: Loading a typechecked module and then using it immediately as a package PUBLIC I tried moving `MyLib.hs` into a directory different than `Test.sh`, but the error message still refers to its correct location! So this error is not guessing the file name of where `MyLib.hs` could be loaded from; instead, it seems to refer correctly to where the module (previously loaded) was. Hmm. -----Original Message----- From: Matthew Pickering <matthewtpickering(a)gmail.com> Sent: Tuesday, June 29, 2021 5:04 PM To: Erdi, Gergo <Gergo.Erdi(a)sc.com> Subject: [External] Re: Loading a typechecked module and then using it immediately as a package Do you have a `MyLib.hs` source file? If you move that somewhere else (another folder) then things might work? On Tue, Jun 29, 2021 at 9:41 AM Erdi, Gergo <Gergo.Erdi(a)sc.com> wrote: > > PUBLIC > > What's weird about it is that if I print the `moduleNameProvidersMap`, I can see `MyLib` inside, and it looks no different than any other module from e.g. `ghc-prim` that I can import into `Test.hs` without any package qualification. Also, why does the error message refer to the file name `input/MyLib.hs`? Why does GHC even know that that is where it would have to be loaded from, if it weren't to be used from an already loaded package? > This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries at https: //www.sc.com/en/our-locations Where you have a Financial Markets relationship with Standard Chartered PLC, Standard Chartered Bank and their subsidiaries (the "Group"), information on the regulatory standards we adhere to and how it may affect you can be found in our Regulatory Compliance Statement at https: //www.sc.com/rcs/ and Regulatory Compliance Disclosures at http: //www.sc.com/rcs/fm Insofar as this communication is not sent by the Global Research team and contains any market commentary, the market commentary has been prepared by the sales and/or trading desk of Standard Chartered Bank or its affiliate. It is not and does not constitute research material, independent research, recommendation or financial advice. Any market commentary is for information purpose only and shall not be relied on for any other purpose and is subject to the relevant disclaimers available at https: //www.sc.com/en/regulatory-disclosures/#market-disclaimer. Insofar as this communication is sent by the Global Research team and contains any research materials prepared by members of the team, the research material is for information purpose only and shall not be relied on for any other purpose, and is subject to the relevant disclaimers available at https: //research.sc.com/research/api/application/static/terms-and-conditions. Insofar as this e-mail contains the term sheet for a proposed transaction, by responding affirmatively to this e-mail, you agree that you have understood the terms and conditions in the attached term sheet and evaluated the merits and risks of the transaction. We may at times also request you to sign the term sheet to acknowledge the same. Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for important information with respect to derivative products.

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Re: Loading a typechecked module and then using it immediately as a package
by Erdi, Gergo 29 Jun '21

29 Jun '21

PUBLIC What's weird about it is that if I print the `moduleNameProvidersMap`, I can see `MyLib` inside, and it looks no different than any other module from e.g. `ghc-prim` that I can import into `Test.hs` without any package qualification. Also, why does the error message refer to the file name `input/MyLib.hs`? Why does GHC even know that that is where it would have to be loaded from, if it weren't to be used from an already loaded package? -----Original Message----- From: Erdi, Gergo Sent: Monday, June 28, 2021 3:04 PM To: 'Matthew Pickering' <matthewtpickering(a)gmail.com> Cc: 'ghc-devs(a)haskell.org' <ghc-devs(a)haskell.org> Subject: RE: [External] Re: Loading a typechecked module and then using it immediately as a package INTERNAL Oh, and one more question. This all works if in `Test.hs` I use a package import for `MyLib`. However, if I remove that, I get an error attempting to use module ‘main:MyLib’ (input/MyLib.hs) which is not loaded So I tried adding an ExposePackage to the DynFlags's packageFlags between loading the library and typechecking `Test.hs`, but I couldn't get that to work: 1. If I just set it in the `hsc_dflags`, it doesn't take. 2. If I use `initUnits` after setting it in `hsc_dflags`, I get a new error: cannot satisfy my-pkg -----Original Message----- From: Erdi, Gergo Sent: Monday, June 28, 2021 2:41 PM To: Matthew Pickering <matthewtpickering(a)gmail.com> Cc: ghc-devs(a)haskell.org Subject: RE: [External] Re: Loading a typechecked module and then using it immediately as a package INTERNAL Thanks, I got this working (after changing it slightly to use the GHC 9.0 API to the UnitState). However, I have some followup questions: 1. In the fakeUnitInfo, what is the relationship between unitLibraries and unitExposedModules? 2. In the fakeUnitInfo, what is the unitImportDirs used for? 3. What is the difference between a PackageId and a PackageName? Other than that, the code registers MyLib into the my-pkg package by letting `load` do the actual heavy lifting. For my purposes, I will need to control this loading myself: only `MyLib`'s typechecked interface should be used, with no actual compilation of definitions. So I wrote some code that makes a ModIface from a TcGblEnv. I seemingly got the whole thing working just by setting mi_exports from the TcGblEnv and leaving everything else with trivial values (fingerprint0 for fingerprints, empty lists for instances, etc.). If `MyLib` has no external dependencies and doesn't define any typeclasses, instances, or type families, is this enough? What is the role of `mi_globals`, should I set that from `tcg_rdr_env`, or should I leave it empty? Thanks, Gergo -----Original Message----- From: Matthew Pickering <matthewtpickering(a)gmail.com> Sent: Friday, June 25, 2021 6:54 PM To: Erdi, Gergo <Gergo.Erdi(a)sc.com> Cc: ghc-devs(a)haskell.org Subject: [External] Re: Loading a typechecked module and then using it immediately as a package ATTENTION: This email came from an external source. Do not open attachments or click on links from unknown senders or unexpected emails. Always report suspicious emails using the Report As Phishing button in Outlook to protect the Bank and our clients. Hi Gergo, Please see a minimal example in this gist. https://clicktime.symantec.com/3Eb2qXqu8Yp6VtdK9d5pNmL7Vc?u=https%3A%2F%2Fg… Cheers, Matt On Fri, Jun 25, 2021 at 10:20 AM Erdi, Gergo via ghc-devs <ghc-devs(a)haskell.org> wrote: > > PUBLIC > > > Hi, > > > > I have the following to .hs files: > > > > MyLib.hs: > > module MyLib where > … > > Test.hs: > > {-# LANGUAGE PackageImports #-} > module Test where > import “my-pkg” MyLib > … > > > > I would like to parse/typecheck/load MyLib.hs into some Unit “my-unit”, then add that to the package “my-pkg”, and then typecheck Test.hs, all in-proc using the GHC API, without putting any other files on disk. How do I do that? > > > > What I tried is loading MyLib.hs after setting the homeUnitId in the DynFlags to “my-unit”, then editing the packageNameMap in the unitState of the DynFlags to may “my-pkg” to “my-unit”: > > setHomeUnit :: (GhcMonad m) => UnitId -> m () > > setHomeUnit unitId = do > > dflags <- getSessionDynFlags > > modifySession $ \h -> h{ hsc_dflags = dflags{ homeUnitId = unitId > } } > > > > registerUnit :: (GhcMonad m) => PackageName -> UnitId -> m () > > registerUnit pkg unitId = modifySession $ \h -> h{ hsc_dflags = > addUnit $ hsc_dflags h } > > where > > addUnit dflags = dflags > > { unitState = let us = unitState dflags in us > > { packageNameMap = M.insert pkg (Indefinite unitId > Nothing) $ packageNameMap us > > } > > } > > > > pipeline = do > > setHomeUnit myUnit > > loadModule =<< typecheckModule =<< parseModule =<< modSumarryFor “MyLib” > > registerUnit myPkg myUnit > > > > setHomeUnit mainUnitId > > typecheckModule =<< parseModule =<< modSumarryFor “Test” > > > > > > Alas, this doesn’t work: the import of `MyLib` from `my-pkg` fails with: > > > > input/linking/Test.hs:5:1: error: > > Could not find module ‘MyLib’ > > It is not a module in the current program, or in any known package. > > > > TBH I’m not very surprised that it didn’t work – that registerUnit function is doing some pretty deep surgery on the unitState that probably breaks several invariants. Still, I wasn’t able to find a better way – all the functions in GHC.Unit.State seem to be for querying only. > > > > Thanks, > > Gergo > > > This email and any attachments are confidential and may also be > privileged. If you are not the intended recipient, please delete all > copies and notify the sender immediately. You may wish to refer to the > incorporation details of Standard Chartered PLC, Standard Chartered > Bank and their subsidiaries at https: //www.sc.com/en/our-locations > > Where you have a Financial Markets relationship with Standard > Chartered PLC, Standard Chartered Bank and their subsidiaries (the > "Group"), information on the regulatory standards we adhere to and how > it may affect you can be found in our Regulatory Compliance Statement > at https: //www.sc.com/rcs/ and Regulatory Compliance Disclosures at > http: //www.sc.com/rcs/fm > > Insofar as this communication is not sent by the Global Research team and contains any market commentary, the market commentary has been prepared by the sales and/or trading desk of Standard Chartered Bank or its affiliate. It is not and does not constitute research material, independent research, recommendation or financial advice. Any market commentary is for information purpose only and shall not be relied on for any other purpose and is subject to the relevant disclaimers available at https: //www.sc.com/en/regulatory-disclosures/#market-disclaimer. > > Insofar as this communication is sent by the Global Research team and contains any research materials prepared by members of the team, the research material is for information purpose only and shall not be relied on for any other purpose, and is subject to the relevant disclaimers available at https: //research.sc.com/research/api/application/static/terms-and-conditions. > > Insofar as this e-mail contains the term sheet for a proposed transaction, by responding affirmatively to this e-mail, you agree that you have understood the terms and conditions in the attached term sheet and evaluated the merits and risks of the transaction. We may at times also request you to sign the term sheet to acknowledge the same. > > Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for important information with respect to derivative products. > _______________________________________________ > ghc-devs mailing list > ghc-devs(a)haskell.org > https://clicktime.symantec.com/3A3FModesGCHWyu3Lvr5tp57Vc?u=http%3A%2F > %2Fmail.haskell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc-devs This email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please delete all copies and notify the sender immediately. You may wish to refer to the incorporation details of Standard Chartered PLC, Standard Chartered Bank and their subsidiaries at https: //www.sc.com/en/our-locations Where you have a Financial Markets relationship with Standard Chartered PLC, Standard Chartered Bank and their subsidiaries (the "Group"), information on the regulatory standards we adhere to and how it may affect you can be found in our Regulatory Compliance Statement at https: //www.sc.com/rcs/ and Regulatory Compliance Disclosures at http: //www.sc.com/rcs/fm Insofar as this communication is not sent by the Global Research team and contains any market commentary, the market commentary has been prepared by the sales and/or trading desk of Standard Chartered Bank or its affiliate. It is not and does not constitute research material, independent research, recommendation or financial advice. Any market commentary is for information purpose only and shall not be relied on for any other purpose and is subject to the relevant disclaimers available at https: //www.sc.com/en/regulatory-disclosures/#market-disclaimer. Insofar as this communication is sent by the Global Research team and contains any research materials prepared by members of the team, the research material is for information purpose only and shall not be relied on for any other purpose, and is subject to the relevant disclaimers available at https: //research.sc.com/research/api/application/static/terms-and-conditions. Insofar as this e-mail contains the term sheet for a proposed transaction, by responding affirmatively to this e-mail, you agree that you have understood the terms and conditions in the attached term sheet and evaluated the merits and risks of the transaction. We may at times also request you to sign the term sheet to acknowledge the same. Please visit https: //www.sc.com/en/regulatory-disclosures/dodd-frank/ for important information with respect to derivative products.

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Is there a way to prevent reboxing in W/W (due to OPAQUE pragma proposal)
by Christiaan Baaij 24 Jun '21

24 Jun '21

Hi Ghc-Devs, I believe I've mostly finished the implementation of GHC proposal 0415 [1], the OPAQUE pragma, over at: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/5562 The only remaining issue is that I'm unsure whether there's a way to prevent reboxing of worker arguments as witnessed here: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/5562/diffs#29ad02619a9f… Note that the reboxing doesn't happen in the worker of the OPAQUE-annotated bindings, because OPAQUE-annotated bindings aren't W/W-transformed, but in a worker of a function that calls the OPAQUE-annotated binding. This reboxing was the reason behind the descision to W/W transform NOINLINE-annotated bindings in: https://gitlab.haskell.org/ghc/ghc/-/commit/b572aadb20c2e41e2f6d7b48401bd0b… But the whole idea behind OPAQUE is not to change calls to the annotated binding f by some call of a name-mangled version of f; so W/W transforming OPAQUE-annoted binders is not an option. Any hints on how to avoid the reboxing (if possible) would be appreciated, like: * Do I need to change something in GHC.Core.Opt.WorkWrap? or * Do I need to change the demand/strictness signature of OPAQUE-annoted bindings? * or something else? Thanks, Christiaan [1] https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0415-o…

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Final Call for Talks: Haskell Implementors' Workshop @ ICFP'21
by Ningning Xie 23 Jun '21

23 Jun '21

Final Call for Talks ACM SIGPLAN Haskell Implementors' Workshop https://icfp21.sigplan.org/home/hiw-2021 Virtual, 22 Aug, 2021 Co-located with ICFP 2021 https://icfp21.sigplan.org/ New: Invited Speaker -------------------- Title: Haskell reinterpreted – large-scale real-world experience with the Mu compiler in Financial Markets Speaker: Bengt Marten Agren, Standard Chartered Bank Important dates --------------- Deadline: Wednesday, 30 June, 2021 (AoE) Notification: Wednesday, 14 July, 2021 Workshop: Sunday, 22 August, 2021 The 13th Haskell Implementors' Workshop is to be held alongside ICFP 2021 this year virtually. 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 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 short 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 2021. 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 encouraged to attend the workshop -- we need your feedback to keep the Haskell ecosystem thriving. Students working with Haskell are specially 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, optimisation 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 should be made via HotCRP. The website is: https://icfp-hiw21.hotcrp.com/ We will also have lightning talks session. These have been very well received in recent years, and we aim to increase the time available to them. Lightning talks 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. Logistics --------- Due to the on-going COVID-19 situation, ICFP (and, consequently, HIW) will be held remotely this year. However, the organizers are still working hard to provide for a great workshop experience. While we are sad that this year will lack the robust hallway track that is often the highlight of HIW, we believe that this remote workshop presents a unique opportunity to include more of the Haskell community in our discussion and explore new modes of communicating with our colleagues. We hope that you will join us in making this HIW as vibrant as any other. Program Committee ----------------- * Dominique Devriese (Vrije Universiteit Brussel) * Daan Leijen (Microsoft Research) * Andres Löh (Well-Typed LLP) * Julie Moronuki (Typeclass Consulting) * John Wiegley (DFINITY) * Ningning Xie (the University of Hong Kong) * Edward Z. Yang (Facebook AI Research) Contact ------- * Ningning Xie <xnning at hku.hk>

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An error occurred
by Simon Peyton Jones 22 Jun '21

22 Jun '21

Ben I'm getting this error "An error occurred while fetching the job log" a lot when trying to look at the result of CI. It seems to come and go. Refreshing the browser generally does not fix it. Coming back later sometimes does. It's frustrating. Do you have any idea what's happening or how I can avoid it? Thanks Simon [cid:image001.png@01D766EC.BBFC2D20]

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CI Status Update
by Ben Gamari 17 Jun '21

17 Jun '21

Hi all, As you may have realized, CI has been a bit of disaster over the last few days. It appears that this is just the most recent chapter in our on-going troubles with Docker image storage, being due to an outage of our upstream storage service [1]. Davean and I have started to implement a plan to migrate away from DreamObjects back to local storage. Unfortunately to complete this migration we need DreamObjects to come back online; I am currently waiting until this occurs. Further updates will come as the situation develops. Cheers, - Ben [1] https://www.dreamhoststatus.com/

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Error message degradation for (<= :: Nat -> Nat -> Constraint) in GHC 9.2+
by Christiaan Baaij 17 Jun '21

17 Jun '21

Hi Ghc-Devs, When upgrading one of our tc plugins https://hackage.haskell.org/package/ghc-typelits-natnormalise to GHC 9.2, one of our tests, repeated here: ``` {-# LANGUAGE DataKinds, TypeFamilies, TypeOperators #-} module TestInEq where import Data.Proxy import GHC.TypeLits proxyInEq :: (a <= b) => Proxy a -> Proxy b -> () proxyInEq _ _ = () proxyInEq1 :: Proxy a -> Proxy (a+1) -> () proxyInEq1 = proxyInEq ``` degraded quite badly in terms of the error message. Where in GHC 9.0.1 we get: ``` TestInEq.hs:11:14: error: • Couldn't match type ‘a <=? (a + 1)’ with ‘'True’ arising from a use of ‘proxyInEq’ • In the expression: proxyInEq In an equation for ‘proxyInEq1’: proxyInEq1 = proxyInEq • Relevant bindings include proxyInEq1 :: Proxy a -> Proxy (a + 1) -> () (bound at TestInEq.hs:11:1) | 11 | proxyInEq1 = proxyInEq | ``` with GHC 9.2.0.20210422 we get: ``` TestInEq.hs:11:14: error: • Couldn't match type ‘Data.Type.Ord.OrdCond (CmpNat a (a + 1)) 'True 'True 'False’ with ‘'True’ arising from a use of ‘proxyInEq’ • In the expression: proxyInEq In an equation for ‘proxyInEq1’: proxyInEq1 = proxyInEq • Relevant bindings include proxyInEq1 :: Proxy a -> Proxy (a + 1) -> () (bound at TestInEq.hs:11:1) | 11 | proxyInEq1 = proxyInEq | ``` Errors messages involving type-level naturals and their operations already weren't the poster-child of comprehensable GHC error messages, but this change has made the situation worse in my opinion. This change in error message is due to: https://gitlab.haskell.org/ghc/ghc/-/commit/eea96042f1e8682605ae68db10f2bcd… Is there a way we can get the nicer pre-9.2.0.2021 error message again before the proper 9.2.1 release? e.g. by doing one of the following: 1. Reinstate `(<=? :: Nat -> Nat -> Bool)` as a builtin type family 2. Somehow add a custom type-error to `Data.Type.Ord.OrdCond` 3. Don't expand type aliases in type errors What do you think? should this be fixed? should this be fixed before the 9.2.1 release? -- Christiaan

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Re[2]: GHC and the future of Freenode
by Sebastian Graf 16 Jun '21

16 Jun '21

Re: memory usage: I get that people don't like bloated Electron clients when they already run a browser instance, but fortunately, Element doesn't need to be run as a standalone app (*). Well, except when you want to search encrypted history. But then you're out of luck with irccloud, too... I run Element in a pinned Firefox tab, and according to its task manager it reports 27.4MB, which is about the same for my WhatsApp tab. It's a bit more than irccloud (about 20MB), but I also have quite a few chats in that one tab. It's also quite a lot less than every individual MR page of our GitLab instance (27-110MB), of which I have pinned about 5-10 at any time, so it really doesn't matter much. Since the Matrix<->Libera.chat bridge works now, I have next to no incentive to push for Matrix at the moment, although I still would prefer it. All arguments have been said, so I won't repeat them. It seems like this discussion will go stale in time without anyone stepping up to force a migration. Fine with me. Sebastian ------ Originalnachricht ------ Von: "Jakub Zalewski" <jakzale(a)gmail.com> An: "Janek Stolarek" <jwstolarek(a)gmail.com>; ghc-devs(a)haskell.org Gesendet: 16.06.2021 17:02:28 Betreff: Re: GHC and the future of Freenode >On Tue Jun 15, 2021 at 3:18 PM CEST, Janek Stolarek wrote: >> Apparently, Freenode deleted all registered users and channels several >> hours ago. > >I guess that should solve the problem of communities being split between >Freenode and Libera. > >If I may add towards using IRC, even though it may seem archaic towards >newcomers: > >- it allows them to join without registration (via web.libera.chat), and >- it allows them to use a client of their choosing (I am not aware of > any stable Matrix clients beside Element). > >From my own experience, Electron-based clients (Element included) >consume unreasonable amounts of RAM: Element is consuming ~700MiB of >RAM just to stay idle on my machine. To give a fair comparison, the tab >for irccloud tends to consume ~300MiB. > >-- >Jakub >_______________________________________________ >ghc-devs mailing list >ghc-devs(a)haskell.org >http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs

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GHC and the future of Freenode
by Ben Gamari 16 Jun '21

16 Jun '21

Hi all, As you may have heard the Freenode IRC network, long the home of #ghc and several other prominent Haskell channels, appears to be in the middle of a rather nasty hostile takeover [1,2,3,4]. As a consequence, it seems it will be necessary to migrate the #ghc community elsewhere. The next question is, of course, where will this be. One option is Liberachat, the spiritual successor of Freenode. However, in recent years I have also heard an increasingly loud choir of users, contributors, and potential-contributors note how archane IRC feels when compared to other modern chat platforms. Using IRC effectively in a collaborative environment essentially requires that all parties use a bouncer; however, this is (understandably) isn't something that most users are willing to do. Consequently, I think it would be wise to expand our search space to include other FOSS platforms. At the moment, I can see the following options: 1. Remain on IRC and move to Liberachat, the spiritual successor of Freenode 2. Remain on IRC and move to OFTC, another widely used network 3. Move to [Matrix] 4. Move to [Zulip] My sense is that of the non-IRC options Matrix is the truest successor to IRC, being a federated protocol with a wide array of (if somewhat immature) clients. I know some of our contributors already use it and in principle one could configure an IRC-to-Matrix bridge for those existing contributors who would rather continue using IRC. Zulip, while also being FOSS, is far more centralized than Matrix and appears to be more of a chat web application than an open protocol. Do you know of any other options? Thoughts? Cheers, - Ben [1]: https://gist.github.com/joepie91/df80d8d36cd9d1bde46ba018af497409 [2]: https://fuchsnet.ch/freenode-resign-letter.txt [3]: https://gist.github.com/aaronmdjones/1a9a93ded5b7d162c3f58bdd66b8f491 [4]: https://mniip.com/freenode.txt [Matrix]: https://www.matrix.org/ [Zulip]:

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