- ghc-devs - Haskell.org

GHC 9.14 status
by Ben Gamari 21 Jun '25

21 Jun '25

Hi all, We are coming up on the final fork for the ghc-9.14 branch. I expect that Vlad's !14136 will land in the next day. The submodule bumps will likely land shortly after. At this rate I expect the fork to be cut on Tuesday, with the first alphas coming around a week after. Naturally, if I have missed anything let me know ASAP. Cheers, - Ben

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RTS: mmap fails on RISC-V with Linux 6.8
by Heinrich Schuchardt 20 Jun '25

20 Jun '25

The following bug related to the Haskell runtime was reported in Launchpad: Haskell's default behaviour of using large-address-space is causing pandoc to stuck in an infinite loop on QEMU 10 Edit https://bugs.launchpad.net/ubuntu/+source/ghc/+bug/2111581 The problem seems to relate to the following loop in osReserveHeapMemory(): https://gitlab.haskell.org/ghc/ghc/-/blob/master/rts/posix/OSMem.c?ref_type… According to the mmap() manpage the address passed to the kernel in only a hint there is no guarantee that the same address will be used for allocation. As shown in the strace logs attached in Launchpad this code can lead to an endless loop when the kernel decides always to return an address below 8 GiB. It might make sense to round up the address to 8 GiB if the returned address is below 8 GiB and reduce *len accordingly instead of retrying. Best regards Heinrich

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Placing GitLab behind Anubis
by Ben Gamari 17 Jun '25

17 Jun '25

Hi all, As you may know, for the last few years we have used a variety of strategies for dealing with the problem of abuse and spam on gitlab.haskell.org. The currently-employed and seemingly most effective technique has been to require manual approval of new account requests. This has always been an uneasy compromise. Not only does this approval process add considerable friction to the contribution process, the increasing prevalence of ill-behaved web crawlers has rendered the approach less and less effective at prevent that form of abuse. For this reason we now exploring alternative approaches. One promising strategy employed by other FOSS GitLab deployments (e.g. gitlab.freedesktop.org) is the Anubis proof-of-work system. Anubis works by forcing the client to perform a small (but non-negligible) amount of work before requests are serviced. This will mean that GitLab users' clients will periodically be asked to perform small amounts of work. While Anubis primarily targets crawlers, it may be that the slight increase in per-request cost might also allow us to lift our manual account approval requirement. Ultimately, the only way to find out is to try. If there are no objections, I will place Anubis in front of GitLab starting next week. During this process we will assess the effectiveness of Anubis at prevent both spam and over-zealous crawlers. This may require a bit of iterative parameter tuning but I am hopeful that the end result might be a more accessible and faster GitLab instance for us all. Let me know what you think. Cheers, - Ben [1] https://github.com/TecharoHQ/anubis

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GHC 9.14 fork status
by Ben Gamari 13 Jun '25

13 Jun '25

Hi all, As those of you at Zurihac may know, we are currently in the process of preparing for the GHC 9.14 fork. This week I have been working through the various necessary core library version bumps and submodule changes. My hope is that we can land this work early next week and declare the fork at some point in the days that follow. I am aware of a few things that we want to land prior to forking: * @int-index's !14136 (Visible forall in GADTs) * testing and enabling of LLVM 20 support * an update of win32-tarballs * Cheng's libffi update (!14392) If you have any further work that you would like to see in 9.14 please do let me know by next Wednesday. If all goes well, my hope is that we can have our first alpha out by the end of this month, with an eye towards a final release in early September. Cheers, - Ben

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GHC 9.14 boot library status
by Ben Gamari 12 Jun '25

12 Jun '25

Hi all, This week I have been pushing through submodule updates and bounds bumps in preparation for the fork of the GHC 9.14 release. Today I have opened merge requests against those boot libraries which will require changes to integrate into 9.14; thankfully, it appears that these changes are all limited to bounds bumps this cycle. In keeping with our release management policy [1], I have updated GHC's submodules to reflect the current releases present on Hackage. I have also updated the submodule tracking spreadsheet [2] to reflect the expected boot library versions on release. Please have a look over the spreadsheet and if you would like to see anything changed here, update it accordingly at some point in the next few weeks. As always, thanks for your efforts! Cheers, - Ben [1] https://gitlab.haskell.org/ghc/ghc-hq/-/blob/main/release-management.mkd?re… [2] https://docs.google.com/spreadsheets/d/19WeWjXPh8Q64qoe3fjs8AswpTHk6uLBD8WG…

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Features for GHC 9.14?
by Ben Gamari 04 Jun '25

04 Jun '25

Hi all, I am currently putting together the GHC status talk for this year's HIW. Do let me know if you anticipate merging any features for the coming 9.14 release which you haven't yet put on GitLab. Cheers, - Ben

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can't move to latest version of llvm on ghc 9.12.2
by George Colpitts 25 May '25

25 May '25

llvm 20 is out but unlike in earlier versions of ghc moving to it means you can no longer use llvm: compiling: ghc -fllvm hello.hs Loaded package environment from /Users/avie/.ghc/aarch64-darwin-9.12.2/environments/default [1 of 2] Compiling Main ( hello.hs, hello.o ) <no location info>: error: [GHC-66599] GHC was not configured with a supported LLVM toolchain Make sure you have installed LLVM between [13 and 20) and reinstall GHC to make -fllvm work from configure: configure: We only support llvm 13 upto 20 (non-inclusive) (found 20.1.1). Can we move to llvm 20 on HEAD and can we revert to the old behavior on ghc 9.12.3? Should I file an ER? Thanks

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GitLab account request
by Florian Ragwitz 16 May '25

16 May '25

Hi, I'd like for the gitlab.haskell.org account request for the account "rafl" to be approved, so that I can participate in issue discussions and submit changes for review, please. Thanks!

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GitLab Account creation request
by Iris 14 May '25

14 May '25

Dear GHC developers, I am interested in contributing to the GHC project and would like to have an account(iris) on the GitLab instance. Best regards, Iris

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LINE and COLUMN pragmas
by Alan & Kim Zimmerman 12 May '25

12 May '25

I recently discovered the `UsePosPragsBit` in the lexer, which can allow emitting the LINE and COLUMN pragmas as tokens instead of processing them directly in the Lexer, updating the position. When exact printing, this behaviour is not desirable. So I am putting together an MR to parse them if they appear, so they do not cause a parser crash, and they can then be exact printed. Question: Where should these pragmas appear in HsDecl Options are - TTG, XXHsDecl - A new HsDecl constructor, with all its concomitant matching everywhere - tuck it in elsewhere, e.g. in `AnnDecl` (or `XXAnnDecl`). Alan

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