[ANNOUNCE] GHC 8.10.5 released

The GHC team is very pleased to announce the availability of GHC 8.10.5.
Source and binary distributions are available at the usual

This release adds native ARM/Darwin support, as well as bringing performance
improvements and fixing numerous bugs of varying severity present in the 8.10

  • First-class support for Apple M1 hardware using GHC’s LLVM ARM backend

  • Fix a bug resulting in segmentation faults where code may be unloaded
    prematurely when using the parallel garbage collector (#19417) along
    with other bugs in the GC and linker (#19147, #19287)

  • Improve code layout fixing certain performance regressions (#18053)
    and other code generation bug fixes (#19645)

  • Bug fixes for signal handling when using the pthread itimer implementation.

  • Improvements to the specializer and simplifier reducing code size and
    and memory usage (#17151, #18923,#18140, #10421, #18282, #13253).

  • Fix a bug where typechecker plugins could be run with an inconsistent
    typechecker environment (#19191).

  • Fix a simplifier bug which lead to an exponential blow up and excessive
    memory usage in certain cases

A complete list of bug fixes and improvements can be found in the release notes: release

As always, feel free to report any issues you encounter via


It seems a bug with a fix not backported to 8.10 is affecting 8.10.5 support for haskell-language-server :worried:


@jneira is this a regression from 8.10.4?

It seems so, taking in account the haskell-language-server functional test suite. We had to mark one test as broken spefically for 8.10.5, related with loading in hls a project which uses a ghc plugin so the effect is less serious than i expected.

Now we are investigating hangs in macos builds (ci and reproduced by an user)

As i commented in the hls pull request we should build in ci (as a not required check) using the ghc branch containing the next minor version (8.10.5 and 9.0.2) to anticipate those bugs before the final relase. I think it would be helpful for ghc devs and us.

For achieve that we would need that the install methods used by the haskell github actions will be able to install the artefacts generated by those branches in gitlab.haskell.org. I think ghcup has that feature so only we would need it in the chocolatey package.

haskell-language-server-wrapper is looking for haskell-language-server-8.10.5. When will that be released?

A version of hls with support for ghc-8.10.5 has been just released: [ANN] haskell-language-server-1.2.0 release!
Unfortunately macos dont have an executable for this version due to build failures see: https://github.com/haskell/haskell-language-server/issues/1913