GHC 9.4.4 released

bgamari - 2022-12-24

The GHC developers are happy to announce the availability of GHC 9.4.4. Binary distributions, source distributions, and documentation are available at

This release is primarily a bugfix release. Bugs fixed include:

  • An issue where the wrong labels were used in the eventlog for events emitted when using info table profiling which was broken in 9.4.3 (#22452)
  • Fix a long standing bug where invalid eventlogs would be produced with long command-lines (#20221)
  • Fix a regression in eta-expansion which resulted in serious performance regressions in 9.4.3 (#22424)
  • Fix the -fdefer-diagnostics flag (#22391)
  • Fixes to several subtle compiler panics. (#22491, #22416, #22549, #22475, #22039)
  • Add necessary write barriers to IORef operations, avoiding potential soundness issues on architectures with weakly-ordered memory models (#22468)

Note that, as GHC 9.4 is the first release series where the release artifacts are all generated by our new Hadrian build system, it is possible that there will be packaging issues. If you enounter trouble while using a binary distribution, please open a ticket. Likewise, if you are a downstream packager, do consider migrating to Hadrian to run your build; the Hadrian build system can be built using cabal-install, stack, or the in-tree bootstrap script. See the accompanying blog post for details on migrating packaging to Hadrian.

We would also like to emphasize that GHC 9.4 must be used in conjunction with Cabal-3.8 or later. This is particularly important for Windows users due to changes in GHC’s Windows toolchain.

We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, 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 Haskelling,

  • Ben