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

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

Internal compiler library

ghc-boot

9.6.7

Internal compiler library

ghc-compact

0.1.0.0

Core library

ghc-heap

9.6.7

GHC heap-walking library

ghc-prim

0.10.0

Core library

ghci

9.6.7

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

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