GHC 9.2.4 is now available

Zubin Duggal - 2022-07-28

The GHC developers are very happy to at announce the availability of GHC 9.2.4. Binary distributions, source distributions, and documentation are available at

This release will include:

  • The new DeepSubsumption language extension which reverses the effects of the Simplified Subsumption Proposal introduced in GHC 9.0. This is an attempt to make GHC 9.2.4 more backwards compatible with GHC 8.10 and eases migration for users who depended on this feature.

    This extension is enabled by default with the Haskell2010 and Haskell98 languages but disabled with the GHC2021 language originally introduced in GHC 9.2.1.

    See the Deep Subsumption Proposal for more details.

  • Fixes for segfaults that may arise due to a bug in the implementation of the keepAlive# primop. This may regress performance for certain programs which use this primop or functions which use the primop, such as withForeignPtr. These regressions are mostly small, but can be larger in certain edge cases. Judicious use of unsafeWithForeignPtr when its argument is known not to statically diverge can mitigate these in many cases. It is our judgment that the critical correctness issues justify the regression in performance and that it is important to get a release out with the fix while we work on a better approach which will improve performance for future releases (#21708).

    We have a wiki page that tracks possible solutions to this problem, and Ben wrote a blog post detailing the introduction of the keepAlive# primop and its history.

  • Fixes for a number of miscompilations on AArch64 and other platforms (#21624, #21773, #20735, #21685).

  • Fixes for segfaults due to bugs in the RTS and GC (#21708, #21880, #21885).

  • Fixing the behaviour of Ctrl-C with GHCi on Windows (#21889).

  • … and much more. See the release notes for a full accounting.

As some of the fixed issues do affect correctness users are encouraged to upgrade promptly.

We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Tweag I/O, Serokell, Equinix, SimSpace, Haskell Foundation, and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release.

As always, do give this release a try and open a ticket if you see anything amiss.

Happy compiling,

  • Zubin