Haskell: GHC 9.6.7 is now available

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A new Haskell blog post/announcement has been posted!

GHC 9.6.7 is now available

Luite Stegeman - 2025-03-24

The GHC developers are very pleased to announce the availability of GHC 9.6.7. Binary distributions, source distributions, and documentation are available on the release page.

GHC 9.6.7 brings number of fixes, including:

• GHC’s internal Unique type has been widened to 64-bits on 32-bit architectures, avoiding potential miscompilations on large projects.
• Fix a runtime crash when using the compacting GC, caused by black holes in large objects.
• Added new flags -fspec-eval and -fspec-eval-dictfun to allow switching off speculative evaluation.

The following libraries have been updated since GHC 9.6.6:

• base-4.18.3.0
• filepath-1.4.301.0
• unix-2.8.6.0
• bytestring-0.11.5.4
• array-0.5.8.0

A more detailed description can be found in the release notes and a full list of changes in GHC!13841 and GHC!13891

Note about Haskell Language Server and building GHC 9.8+:

The change of Unique to 64 bit (GHC#22010) adds the exported symbol ghc_unique_counter64 to the RTS. Unfortunately it’s impossible to avoid this without breaking other things. If you encounter a linker error related to ghc_unique_counter64 when building GHC (or building a GHC-derived package like ghc-lib-parser) with GHC 9.6.7, you probably have to add this fix to the program you’re building.

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Get the full details here: GHC 9.6.7 is now available — The Glasgow Haskell Compiler