zubin - 2025-12-27

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

GHC 9.12.3 is a bug-fix release fixing many issues of a variety of severities and scopes, including:

• Fix a number of crashes and miscompilations in the compiler frontend (#25004, #25960, #26256)
• Improvements to efficiency of the runtime linker (#26009)
• Fixes for several bugs in bytecode generation and the bytecode interpreter (#23210, #25975, #25750)
• Fixes for bugs in the handling of WHITEHOLEs in the RTS (#26204, #26205)
• Fix incorrect code generation for SSE vector operations (#25859)
• Fix a use-after-free in the Windows runtime linker (#26613)
• Support for synchronous JSFFI exports for the wasm backend
• And many more!

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.

GHC development is sponsored by:

• Juspay
• QBayLogic
• Channable
• Haskell Foundation
• Serokell
• Well-Typed
• Tweag
• Dotcom-Monitor
• LoadView
• Web Hosting Buddy
• Find My Electric
• Standard Chartered
• UpCloud
• Mercury

We would like to thank 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.