GHC 9.12.3-rc2 is now available

The GHC developers are very pleased to announce the availability
of the second release candidate for GHC 9.12.3. Binary distributions, source
distributions, and documentation are available at downloads.haskell.org and
via GHCup.

GHC 9.12.3 is a bug-fix release fixing several issues of a variety of
severities and scopes. A full accounting of these fixes can be found in the
release notes. As always, GHC’s release status, including planned future
releases, can be found on the GHC Wiki status.

This release candidate will have a two-week testing period. If all goes well
the final release will be available the week of 24 November 2025.

The changes from the first release candidate are

  • Fix a regression resulting in a panic with empty cases (#26442, #25960).
  • Fix for a potential segfault in the bytecode interpreter (#23210).
  • Fix for a regression with tabs not being allowed in string gaps (#26415).
  • Fix for a crash with the non-moving GC (#26204).
  • A rework of how internal symbols used by the code-generator are handled to
    adapt to changes in the Apple toolchain, enabling this release to bootstrap on
    macOS 26 Tahoe (#26166).

GHC development is sponsored by:

We would like to that these sponsors 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.

13 Likes

Will there be another RC, or will it be released soon?

1 Like

I’m preparing another RC currently. The release has been delayed due to a number of bugs that were surfaced meanwhile.

3 Likes