June 2017 - ghc-devs - Haskell.org

GHC's module hierarchy
by Simon Peyton Jones 03 Oct '19

03 Oct '19

Dear ghc-devs hsyl20 proposes a radical overhaul of the module structure of GHC itself. He or she suggested it six months ago in https://ghc.haskell.org/trac/ghc/ticket/13009 and has now offered a monster patch https://phabricator.haskell.org/D3647 It's clearly the result of a lot of work, but I was the only one who responded on the original ticket, and it'll affect all of your lives in a very immediate way. So, would you like to * consider the idea * look at the actual re-mapping of modules hsyl20 proposals * express an opinion about whether to go ahead Probably the ticket, rather than Phab, is the best place to comment on the general idea. I'd like to thank hsyl20. GHC's rather flat module structure has grown incrementally over years. But still, there are pros and cons. Simon

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Default options for -threaded
by lonetiger＠gmail.com 04 Jan '19

04 Jan '19

Hi All, A user on https://ghc.haskell.org/trac/ghc/ticket/11054 has asked why -N -qa isn’t the default for -threaded. I’m afraid I don’t know a good reason why it’s not. Can anyone help shed some light on this? If there is no good reason, Would anyone object to making it the default? Thanks, Tamar

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[ANNOUNCE] GHC 8.2.1 release candidate 1
by Ben Gamari 03 Oct '17

03 Oct '17

Hello everyone, The GHC team is very pleased to announce the first candidate of the 8.2.1 release of the Glasgow Haskell Compiler. Source and binary distributions are available at https://downloads.haskell.org/~ghc/8.2.1-rc1/ This is the first of a few release candidates leading up the final 8.2.1 release. This release will feature, * A new type-indexed Typeable implementation * The long awaited Backpack * Deriving strategies for disambiguating DeriveAnyClass, GeneralizedNewtypeDeriving, and stock mechanisms * Overloaded record fields * Improved compiler performance * Better code generation through more robust tracking of join points * Compact regions for more efficient garbage collection and serialization * Better support for machines with non-uniform memory architectures * More robust support for levity (e.g. RuntimeRep) polymorphism * A simple interface for streaming eventlog data from live processes * Further refinement of DWARF support Unfortunately there are still a few known issues in this release, including a few compiler panics (#13233, #13509) and a memory leak in the simplifier (#13426) which may adversely affect heap sizes and compilation time for some modules. This memory leak unfortunately made it impossible to provide a 32-bit Windows distribution for this candidate; this will be resolved in -rc2. As always, please let us know if you have difficulty. Thanks to everyone who has contributed to this release! Happy testing, - Ben

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Crossreferenced GHC 8.0.2
by Robin Palotai 29 Aug '17

29 Aug '17

Hello GHC devs, I ran haskell-indexer [1] on the GHC 8.0.2 tarball, partly because I find myself reading GHC source from time to time while working on the indexer, and partly since it's fun. First, here you can click around [2] and find where beloved functions are called from: http://stuff.codereview.me/#ghc/compiler/hsSyn/HsBinds.hs?corpus&signature (scroll down a bit, imports are not linked yet). Second, the way I indexed was pretty simple. I took the output of `make`, replaced the ghc used with the ghc_kythe_wrapper, and filtered the lines which included '-c', since I noticed that those duplicate previous large compile lines. This only indexes the stage1 compilation AFAIU. Feel free to suggest a better way to tap into the compilations to get everything properly indexed (and possibly only once). Any comments welcome! Robin [1]: https://github.com/google/haskell-indexer [2]: TLDR UI quirks: - Click the :: in top-left to navigate file tree - Ctrl-Click (on linux) to go directly to definition (otherwise click stuff from bottom pane) - Bottom pane often hides content, close it if stuck.

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can't validate on Linux
by Richard Eisenberg 10 Jul '17

10 Jul '17

Hi devs, When I try validating my patch, validation fails with > ... > Registering library for ghc-prim-0.5.0.0.. > ghc-cabal: '/home/rae/ghc/ghc-valid/bindisttest/install > dir/lib/ghc-8.3.20170312/bin/ghc-pkg' exited with an error: > ghc-pkg: Couldn't open database /home/rae/ghc/ghc-valid/bindisttest/install > dir/lib/ghc-8.3.20170312/package.conf.d for modification: {handle: > /home/rae/ghc/ghc-valid/bindisttest/install > dir/lib/ghc-8.3.20170312/package.conf.d/package.cache.lock}: hLock: invalid > argument (Bad file descriptor) > make[3]: *** [ghc.mk:990: install_packages] Error 1 > make[2]: *** [Makefile:51: install] Error 2 > make[1]: *** [bindisttest/ghc.mk:33: test_bindist] Error 2 > make: *** [Makefile:127: test_bindist] Error 2 Any advice? Thanks! Richard

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Haskell Implementors' Workshop Call for Talks
by Richard Eisenberg 04 Jul '17

04 Jul '17

Call for Contributions ACM SIGPLAN Haskell Implementors' Workshop http://icfp17.sigplan.org/track/hiw-2017 Oxford, UK, 9 September, 2017 Co-located with ICFP 2017 http://www.icfpconference.org/icfp2017/ Important dates --------------- Proposal Deadline: Thursday, 6 July, 2017 Notification: Thursday, 20 July, 2017 Workshop: Saturday, 9 September, 2017 The 9th Haskell Implementors' Workshop is to be held alongside ICFP 2017 this year in Oxford. 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 impromptu 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 2017. 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-hiw17.hotcrp.com/ We will also have a lightning talks session which will be organised on the day. These talks will be 5-10 minutes, depending on available time. 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 ----------------- * Richard A. Eisenberg -- chair (Bryn Mawr College) * Adam Gundry (Well-Typed) * Bartosz Nitka (Facebook) * Wren Romano (X, formerly Google[x]) * Alejandro Serrano Mena (Utrecht University) * Jan Stolarek (University of Edinburgh) Contact ------- * Richard A. Eisenberg <rae(a)cs.brynmawr.edu>

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Which stable GHC release is expected to have support for linear types?
by Wolfgang Jeltsch 30 Jun '17

30 Jun '17

Hi! The blog post on http://blog.tweag.io/posts/2017-03-13-linear-types.html says, “We are targeting a merge by the time of the 8.4 release of GHC.” Does this mean that GHC 8.4 is expected to have support for linear types, or does it mean that the merge should happen after a GHC 8.4 branch has been forked off from the HEAD branch, so that only GHC 8.6 will have support for linear types? All the best, Wolfgang

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Windows broken
by Simon Peyton Jones 29 Jun '17

29 Jun '17

Help please! Suddenly my Windows build has stopped working. See below. What should I do? I'm totally stuck. This has never happened before. I get this: GHC path canonicalised to: c:/fp/ghc-8.0.2/bin/ghc checking build system type... x86_64-pc-msys checking host system type... x86_64-pc-msys checking target system type... x86_64-pc-msys Build platform inferred as: x86_64-unknown-mingw32 Host platform inferred as: x86_64-unknown-mingw32 Target platform inferred as: x86_64-unknown-mingw32 GHC build : x86_64-unknown-mingw32 GHC host : x86_64-unknown-mingw32 GHC target : x86_64-unknown-mingw32 LLVM target: x86_64-unknown-mingw32 checking for path to top of build tree... C:/code/HEAD configure: Checking for Windows toolchain tarballs... configure: Extracting Windows toolchain from archives (may take a while)... configure: In-tree MingW-w64 tree created configure: Making in-tree perl tree configure: In-tree perl tree created checking whether the C compiler works... no configure: error: in `/c/code/HEAD': configure: error: C compiler cannot create executables See `config.log' for more details Something wrong with the gcc.exe? Config.log has this gcc version 6.3.0 (Rev2, Built by MSYS2 project) configure:4950: $? = 0 configure:4939: C:/code/HEAD/inplace/mingw/bin/gcc.exe -V >&5 gcc.exe: error: unrecognized command line option '-V' gcc.exe: fatal error: no input files compilation terminated. configure:4950: $? = 1 configure:4939: C:/code/HEAD/inplace/mingw/bin/gcc.exe -qversion >&5 gcc.exe: error: unrecognized command line option '-qversion'; did you mean '--version'? gcc.exe: fatal error: no input files compilation terminated. configure:4950: $? = 1 configure:4970: checking whether the C compiler works configure:4992: C:/code/HEAD/inplace/mingw/bin/gcc.exe conftest.c >&5 configure:4996: $? = 1 configure:5034: result: no configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "The Glorious Glasgow Haskell Compilation System" | #define PACKAGE_TARNAME "ghc-8.3" | #define PACKAGE_VERSION "8.3" | #define PACKAGE_STRING "The Glorious Glasgow Haskell Compilation System 8.3" | #define PACKAGE_BUGREPORT "glasgow-haskell-bugs(a)haskell.org" | #define PACKAGE_URL "" | /* end confdefs.h. */ | | int | main () | { | | ; | return 0; | } configure:5039: error: in `/c/code/HEAD': configure:5041: error: C compiler cannot create executables

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Thank you
by Simon Peyton Jones 29 Jun '17

29 Jun '17

Ryan I wanted to thank you for all the work you are putting into GHC at the moment. * You often produce nice small repro cases from other people's bug reports * you often bisect to the patch caused the bug; * your analysis is usually spot on; * you are actively maintaining the generics stuff * you contribute fixes In short, terrific. Thank you! Simon

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hoopl dependency
by Simon Peyton Jones 27 Jun '17

27 Jun '17

Devs, Matko (an intern here at MSR) says Matko Bosnjak 19:02: Hi Simon, There's a 'bug' in some of the latest commits of ghc on git. When running ./build I get: Error: libraries/hoopl/LICENSE doesn't exist. Maybe you haven't done 'git submodule update --init'? at ./boot line 112, <PACKAGES> line 54. Someone removed the dependency on hoopl library, but hasn't removed it from the 'packages' file. What should he do? Simon

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