2.7. Version 9.6.7

The LLVM backend of this release is to be used with LLVM 11, 12, 13, 14 or 15.

2.7.1. Significant Changes

Issues fixed in this release include:

2.7.1.1. Compiler

  • Fixed a bug that caused GHC to panic when using the AArch64 ncg and -fregs-graph on certain programs (#24941).
  • Fix invalid optimisation of Cmm programs on 32-bit platforms when targetting 64-bit targets (#24893 and #24700).
  • Improve float-out surrounding applications of runRW# (#25055).
  • Fix -fregs-graph crash when targetting AArch64 (#24941).
  • Fix code generation of foreign exports with more than 6 arguments when some are subword-width (#24314).
  • Fix recompilation avoidance behavior of -fwrite-if-simplified-core (#24656).
  • Fix linking error when TypeData and StrictData are in use (#24620).
  • -Wmissing-home-modules now behaves correctly when multiple units have expose the same module name (#25122).
  • Adjust the demand signature of the prompt# to avoid invalid optimisation of non-terminating programs (#25439).
  • GHC’s internal Unique type has been widened to 64-bits on 32-bit architectures, avoiding potential miscompilations on large projects (#22010).
  • Fix LLVM version detection on newer LLVM versions (#25606).
  • Determine max_n_capabilities at RTS startup, removing the previous static cap at 256 (#25560).
  • Fix out-of-bounds memory mapping logic, resolving an infinite loop on FreeBSD (#25492).
  • Find C++ probing when GCC version is the latest but G++ is old (#23118).
  • Consider Wanteds with rewriters as insoluble, fixing a situation where the program fails to typecheck but no errors are reported (#25325).
  • Fix x86 NCG foreign argument promotion. The x86 NCG now correctly promotes 8 bit and 16 bits arguments by sign extension (#25018).
  • Fix GHC flag -working-dir for foreign files (#25150).
  • Added new flags -fspec-eval and -fspec-eval-dictfun to allow switching off speculative evaluation (#25284).
  • Fix a runtime crash when using the compacting GC, caused by black holes in large objects (#24791).

2.7.1.2. Hadrian and builds

  • Bump the minimum version of the directory dependency for Hadrian to 1.3.9.0 to avoid a race condition on Windows (##24382). Also updated the bootstrap build plans for hadrian.
  • Hadrian: Set -this-package-name. This fixes package imports for ghci-multi and was required to update the unix package.
  • Add Ubuntu 22.04 builds for nightlies and release (#25317).

2.7.1.3. JavaScript backend

  • Fix compiler crash involving rubbish literals (#25177, #24664).

2.7.1.4. base

  • Bump version to 4.18.2.2
  • Fix spurious closing of file descriptors after fork on platforms using the KQueue event manager backend (#24672), visible on FreeBSD.

2.7.1.5. Other Core Libraries

  • The filepath library has been upgraded to 1.4.301.0, fixing a potentially exploitable behavior with splitFileName on Windows (#24597).
  • unix-2.8.6.0 is included, fixing an issue affecting musl targets.
  • bytestring has been upgraded to 0.11.5.4, fixing a race condition in
    toLazyByteString that could generate wrong results if two threads concurrently evaluated the result.
  • array has been upgraded to 0.5.8.0.
  • ghc-bignum: the bundled gmp library has been upgraded to 6.3.0.

2.7.1.6. Included libraries

The package database provided with this distribution also contains a number of packages other than GHC itself. See the changelogs provided with these packages for further change information.

Package Version Reason for inclusion
ghc 9.6.7.20250131 The compiler itself
Cabal-syntax 3.10.3.0 Dependency of ghc-pkg utility
Cabal 3.10.3.0 Dependency of ghc-pkg utility
Win32 2.13.3.0 Dependency of ghc library
array 0.5.8.0 Dependency of ghc library
base 4.18.3.0 Core library
binary 0.8.9.1 Dependency of ghc library
bytestring 0.11.5.4 Dependency of ghc library
containers 0.6.7 Dependency of ghc library
deepseq 1.4.8.1 Dependency of ghc library
directory 1.3.8.5 Dependency of ghc library
exceptions 0.10.7 Dependency of ghc and haskeline library
filepath 1.4.301.0 Dependency of ghc library
ghc-boot-th 9.6.7.20250131 Internal compiler library
ghc-boot 9.6.7.20250131 Internal compiler library
ghc-compact 0.1.0.0 Core library
ghc-heap 9.6.7.20250131 GHC heap-walking library
ghc-prim 0.10.0 Core library
ghci 9.6.7.20250131 The REPL interface
haskeline 0.8.2.1 Dependency of ghci executable
hpc 0.6.2.0 Dependency of hpc executable
integer-gmp 1.1 Core library
libiserv 9.6.7.20250131 Internal compiler library
mtl 2.3.1 Dependency of Cabal library
parsec 3.1.16.1 Dependency of Cabal library
pretty 1.1.3.6 Dependency of ghc library
process 1.6.19.0 Dependency of ghc library
stm 2.5.1.0 Dependency of haskeline library
template-haskell 2.20.0.0 Core library
terminfo 0.4.1.6 Dependency of haskeline library
text 2.0.2 Dependency of Cabal library
time 1.12.2 Dependency of ghc library
transformers 0.6.1.0 Dependency of ghc library
unix 2.8.6.0 Dependency of ghc library
xhtml 3000.2.2.1 Dependency of haddock executable