January 2020 - Glasgow-haskell-users

[ANNOUNCE] GHC 8.8.2 is now available
by Ben Gamari 25 Feb '20

25 Feb '20

Hello everyone, The GHC team is proud to announce the release of GHC 8.8.2. The source distribution, binary distributions, and documentation are available at https://downloads.haskell.org/~ghc/8.8.2 Release notes are also available [1]. This release fixes a handful of issues affecting 8.8.1: - A bug (#17088) in the compacting garbage collector resulting in segmentations faults under specific circumstances. Note that this may affect user programs even if they did not explicitly request the compacting GC (using the -c RTS flag) since GHC may fallback to compacting collection during times of high memory pressure. - A code generation bug (#17334) resulting in GHC panics has been fixed. - A bug in the `process` library causing builds using `hsc2hs` to fail non-deterministically on Windows has been fixed (Trac #17480) - A typechecker bug (#12088) resulting in programs being unexpectedly rejected has been fixed. - A bug in the implementation of compact normal forms resulting in segmentation faults in some uses (#17044) has been fixed. - A bug causing GHC to incorrectly complain about incompatible LLVM versions when using LLVM 7.0.1 has been fixed (#16990). As always, if anything looks amiss do let us know. Happy compiling! Cheers, - Ben [1] https://downloads.haskell.org/ghc/8.8.2/docs/html/users_guide/8.8.2-notes.h…

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[ANNOUNCE] Glasgow Haskell Compiler 8.10.1-rc1 released
by Ben Gamari 26 Jan '20

26 Jan '20

Hello all, The GHC team is happy to announce the availability of the first release candidate of GHC 8.10.1. Source and binary distributions are available at the usual place: https://downloads.haskell.org/ghc/8.10.1-rc1/ GHC 8.10.1 will bring a number of new features including: * The new UnliftedNewtypes extension allowing newtypes around unlifted types. * The new StandaloneKindSignatures extension allows users to give top-level kind signatures to type, type family, and class declarations. * A new warning, -Wderiving-defaults, to draw attention to ambiguous deriving clauses * A number of improvements in code generation, including changes * A new GHCi command, :instances, for listing the class instances available for a type. * An upgraded Windows toolchain lifting the MAX_PATH limitation * A new, low-latency garbage collector. * Improved support profiling, including support for sending profiler samples to the eventlog, allowing correlation between the profile and other program events This is the first and likely final release candidate. For a variety of reasons, it comes a few weeks later than the original schedule of release late December. However, besides a few core libraries book-keeping issues this candidate is believed to be in good condition for the final release. As such, the final 8.10.1 release will likely come in two weeks. Note that at the moment we still require that macOS Catalina users exempt the binary distribution from the notarization requirement by running `xattr -cr .` on the unpacked tree before running `make install`. In addition, we are still looking for any Alpine Linux to help diagnose the correctness issues in the Alpine binary distribution [1]. If you use Alpine any you can offer here would be greatly appreciated. Please do test this release and let us know if you encounter any other issues. Cheers, - Ben [1] https://gitlab.haskell.org/ghc/ghc/issues/17508 [2] https://gitlab.haskell.org/ghc/ghc/issues/17418

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GHC Full Bootstrap from Source on macOS
by Steven Smith 19 Jan '20

19 Jan '20

Is there a guide or script to build ghc from source (not the prebuilt binary)? At MacPorts we’re running into issues on macOS Catalina 10.15 with the bootstrapped-from-prebuilt ghc. See https://trac.macports.org/ticket/59467 . It would preferable and probably more robust to be able to bootstrap everything from source, and highly preferable to be able to do this with a clang compiler of choice.

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GHC 8.8.2 Bootstrap Build Fails on macOS Catalina 10.15, undeclared identifier 'TAG_MASK'
by Steven Smith 17 Jan '20

17 Jan '20

I’m trying to upgrade the MacPorts ghc install to the latest 8.8.2. The build fails with: > error: use of undeclared identifier 'TAG_MASK' > :info:build return (StgWord)p & TAG_MASK; This is an error observed with previous ghc versions and on other systems, so I do not believe it is macOS-specific. Also, the MacPorts build process simply follows the ghc Build & Install instructions: https://github.com/ghc/ghc/blob/master/README.md#building--installing Is there a simple fix by adding an extra flag somewhere? Logs: > :info:build In file included from compiler/ghci/keepCAFsForGHCi.c:1:0: error: > :info:build In file included from includes/Rts.h:191:0: error: > :info:build includes/rts/storage/ClosureMacros.h:211:25: error: > :info:build error: use of undeclared identifier 'TAG_MASK' > :info:build return (StgWord)p & TAG_MASK; > :info:build ^ > :info:build | > :info:build 211 | return (StgWord)p & TAG_MASK; > :info:build | ^ > :info:build includes/rts/storage/ClosureMacros.h:217:40: error: > :info:build error: use of undeclared identifier 'TAG_MASK' > :info:build return (StgClosure*)((StgWord)p & ~TAG_MASK); > :info:build ^ > :info:build | > :info:build 217 | return (StgClosure*)((StgWord)p & ~TAG_MASK); > :info:build | ^ > :info:build includes/rts/storage/ClosureMacros.h:223:46: error: > :info:build error: use of undeclared identifier 'TAG_MASK' > :info:build return (const StgClosure*)((StgWord)p & ~TAG_MASK); > :info:build ^

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[ANNOUNCE] GHC 8.8.2-rc1 is now available
by Ben Gamari 02 Jan '20

02 Jan '20

Hello everyone, The GHC team is proud to announce the first release candidate of GHC 8.8.2. The source distribution, binary distributions, and documentation are available at https://downloads.haskell.org/~ghc/8.8.2-rc1 Release notes are also available [1]. This release fixes a handful of issues affecting 8.8.1: - A bug (#17088) in the compacting garbage collector resulting in segmentations faults under specific circumstances. Note that this may affect user programs even if they did not explicitly request the compacting GC (using the -c RTS flag) since GHC may fallback to compacting collection during times of high memory pressure. - A code generation bug (#17334) resulting in GHC panics has been fixed. - A bug in the `process` library causing builds using `hsc2hs` to fail non-deterministically on Windows has been fixed (Trac #17480) - A typechecker bug (#12088) resulting in programs being unexpectedly rejected has been fixed. - A bug in the implementation of compact normal forms resulting in segmentation faults in some uses (#17044) has been fixed. - A bug causing GHC to incorrectly complain about incompatible LLVM versions when using LLVM 7.0.1 has been fixed (#16990). As always, if anything looks amiss do let us know. Happy compiling! Cheers, - Ben [1] https://downloads.haskell.org/ghc/8.8.2-rc1/docs/html/users_guide/8.8.2-not…

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[ANNOUNCE] Glasgow Haskell Compiler 8.10.1-alpha2 released
by Ben Gamari 02 Jan '20

02 Jan '20

Hello all, The GHC team is happy to announce the availability of the first alpha release in the GHC 8.10 series. Source and binary distributions are available at the usual place: https://downloads.haskell.org/ghc/8.10.1-alpha2/ GHC 8.10.1 will bring a number of new features including: * The new UnliftedNewtypes extension allowing newtypes around unlifted types. * The new StandaloneKindSignatures extension allows users to give top-level kind signatures to type, type family, and class declarations. * A new warning, -Wderiving-defaults, to draw attention to ambiguous deriving clauses * A number of improvements in code generation, including changes * A new GHCi command, :instances, for listing the class instances available for a type. * An upgraded Windows toolchain lifting the MAX_PATH limitation * A new, low-latency garbage collector. * Improved support profiling, including support for sending profiler samples to the eventlog, allowing correlation between the profile and other program events This release is the second alpha of the 8.10 pre-release cycle. The release will be a release candidate in roughly three weeks. If all goes well the final release will be cut roughly two weeks after the candidate, in mid-January. This being an alpha release, there are a few issues that are still outstanding: * The new Alpine Linux binary distribution is not present due to an apparent correctness issue [1]; any help Alpine users can offer here would be greatly appreciated. * We have yet to sort out compliance with Apple's notarization requirements [2] which will be likely be necessary for users of macOS Catalina. However, until this has been sorted out Catalina users can exempt the current macOS binary distribution from the notarization requirement themselves by running `xattr -cr .` on the unpacked tree before running `make install`. * There is one remaining non-regression correctness issue which we plan to fix for the final 8.10.1 but that is not fixed in this release. Please do test this release and let us know if you encounter any other issues. Cheers, - Ben [1] https://gitlab.haskell.org/ghc/ghc/issues/17508 [2] https://gitlab.haskell.org/ghc/ghc/issues/17418

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