2.2. Version 9.6.2

The significant changes to the various parts of the compiler are listed below. See the migration guide on the GHC Wiki for specific guidance on migrating programs to this release.

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

  • A simplifier bug resulting in compiler crashes in some situations involving rules has been fixed.
  • Several issues affecting the bytecode interpreter’s handling of optimised programs have been fixed (%s23068, %s22958)
  • A specialisation bug resulting looping of some programs involving non-trivial chains of instances (namely, requiring UndecidableInstances) has been fixed (%s22549)
  • A bug resulting in crashes of programs using the new listThreads# primop has been fixed (%s23071).
  • A compiler crash triggered by certain uses of quantified constraints has been fixed (%s23171)
  • Various bugs in the Javascript backend have been fixed (%s23399, %s23360, %s23346)
  • The non-moving garbage collector’s treatment of weak pointers has been revamped which should allow more reliable finalization of Weak# closures (%s22327)
  • The non-moving garbage collector now bounds the amount of marking it will do during the post-marking stop-the-world phase, greatly reducing tail latencies in some programs (%s22929)
  • A missing write barrier in the non-moving collector’s handling of selector thunks has been fixed (%s22930).

2.2.1. 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 9.6.2 The compiler itself
Cabal-syntax Dependency of ghc-pkg utility
Cabal Dependency of ghc-pkg utility
Win32 Dependency of ghc library
array Dependency of ghc library
base Core library
binary Dependency of ghc library
bytestring Dependency of ghc library
containers 0.6.7 Dependency of ghc library
deepseq Dependency of ghc library
directory Dependency of ghc library
exceptions 0.10.7 Dependency of ghc and haskeline library
filepath Dependency of ghc library
ghc-boot-th 9.6.2 Internal compiler library
ghc-boot 9.6.2 Internal compiler library
ghc-compact Core library
ghc-heap 9.6.2 GHC heap-walking library
ghc-prim 0.10.0 Core library
ghci 9.6.2 The REPL interface
haskeline Dependency of ghci executable
hpc Dependency of hpc executable
integer-gmp 1.1 Core library
libiserv 9.6.2 Internal compiler library
mtl 2.3.1 Dependency of Cabal library
parsec Dependency of Cabal library
pretty Dependency of ghc library
process Dependency of ghc library
stm Dependency of haskeline library
template-haskell Core library
terminfo Dependency of haskeline library
text 2.0.2 Dependency of Cabal library
time 1.12.2 Dependency of ghc library
transformers Dependency of ghc library
unix Dependency of ghc library
xhtml 3000.2.2.1 Dependency of haddock executable