[ANNOUNCE] GHC-8.10.1-alpha2 released

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

GHC 8.10.1 will bring a number of new features including:

  • The new UnliftedNewtypes extension allowing newtypes around unlifted

  • The new StandaloneKindSignatures extension allows users to give
    top-level kind signatures to type, type family, and class

  • 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

  • The new Alpine Linux binary distribution is not present due to an
    apparent correctness issue; any help Alpine users can offer here
    would be greatly appreciated.

  • We have yet to sort out compliance with Apple’s notarization
    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


  • Ben