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  "path": "/t/ghc-9-12-4-rc1-is-now-available/13786#post_1",
  "publishedAt": "2026-03-13T09:15:30.000Z",
  "site": "https://discourse.haskell.org",
  "tags": [
    "downloads.haskell.org",
    "GHCup",
    "release notes",
    "status",
    "Juspay",
    "QBayLogic",
    "Channable",
    "Haskell Foundation",
    "Serokell",
    "Well-Typed",
    "Tweag",
    "Dotcom-Monitor",
    "LoadView",
    "Web Hosting Buddy",
    "Find My Electric",
    "Standard Chartered",
    "UpCloud",
    "Mercury",
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  "textContent": "The GHC developers are very pleased to announce the availability\nof the release candidate for GHC 9.12.4. Binary distributions, source\ndistributions, and documentation are available at downloads.haskell.org and\nvia GHCup.\n\nGHC 9.12.4 is a bug-fix release fixing many issues of a variety of\nseverities and scopes, including:\n\n  * Fixed a critical code generation regression where sub-word division produced\nincorrect results (#26711, #26668), similar to the bug fixed in 9.12.2\n  * Numerous fixes for register allocation bugs, preventing data corruption\nwhen spilling and reloading registers\n(#26411, #26526, #26537, #26542, #26550)\n  * Fixes for several compiler crashes, including issues with\nCSE (#25468), SetLevels (#26681),\nimplicit parameters (#26451), and the type-class specialiser (#26682)\n  * Fixed cast worker/wrapper incorrectly firing on INLINE functions (#26903)\n  * Fixed LLVM backend miscompilation of bit manipulation operations\n(#20645, #26065, #26109)\n  * Fixed associated type family and data family instance changes not triggering\nrecompilation (#26183, #26705)\n  * Fixed negative type literals causing the compiler to hang (#26861)\n  * Improvements to determinism of compiler output (#26846, #26858)\n  * Fixes for eventlog shutdown deadlocks (#26573)\nand lost wakeups in the RTS (#26324)\n  * Fixed split sections support on Windows (#26696, #26494) and the LLVM backend (#26770)\n  * Fixes for the bytecode compiler, PPC native code generator, and Wasm backend\n  * The runtime linker now supports COMMON symbols (#6107)\n  * Improved backtrace support: backtraces for `error` exceptions are now\nevaluated at throw time\n  * `NamedDefaults` now correctly requires the class to be standard or have an\nin-scope default declaration, and handles poly-kinded classes (#25775, #25778, #25882)\n  * … and many more\n\n\n\nA full accounting of these fixes can be found in the\nrelease notes. As always, GHC’s release status, including planned future\nreleases, can be found on the GHC Wiki status.\n\nThis release candidate will have a two-week testing period. If all goes well\nthe final release will be available the week of 26 March 2026.\n\nGHC development is sponsored by:\n\n  * Juspay\n  * QBayLogic\n  * Channable\n  * Haskell Foundation\n  * Serokell\n  * Well-Typed\n  * Tweag\n  * Dotcom-Monitor\n  * LoadView\n  * Web Hosting Buddy\n  * Find My Electric\n  * Standard Chartered\n  * UpCloud\n  * Mercury\n\n\n\nWe would like to thank these sponsors and other anonymous contributors\nwhose on-going financial and in-kind support has facilitated GHC maintenance\nand release management over the years. Finally, this release would not have\nbeen possible without the hundreds of open-source contributors whose work\ncomprise this release.\n\nAs always, do give this release a try and open a ticket if you see\nanything amiss.",
  "title": "GHC 9.12.4-rc1 is now available"
}