# 9. Release notes for version 8.10.7¶

The significant changes to the various parts of the compiler are listed in the following sections.

The LLVM backend of this release is to be used with LLVM versions 9 through 12.

## 9.1. Portability fixes¶

• Actually fix a linking portability issue on macOS that resulted in undefined symbol errors for ___darwin_check_fd_set_overflow (#19950), working around a bug in certain versions of XCode 11. We claimed to have fixed this in GHC 8.10.6, but alas this wasn’t the case. The fix was originally tested on the master branch, which uses a different build configuration from the 8.10 branch. We have now tested the fix on the GHC 8.10 branch and finally squashed the bug.

## 9.2. Known issues¶

• A long-standing bug (#16893) which can cause some applications of unsafeCoerce to segmentation fault is only partially fixed in this release. This release only avoids this issue in the uses of unsafeCoerce in Data.Typeable.Internal, which was the proximate cause of #16893.

However, it is possible that this bug could manifest in user-code using unsafeCoerce to perform dynamic type checks. See the ticket for details.

We expect that this issue will be fixed in the next major release of GHC.

• A long-standing bug (#17760) where some uses of the touch# primop can be dropped by the simplifier is present in this release. This bug will be fixed in GHC 9.0.1. In the meantime, see the ticket for mitigations.

## 9.3. 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

8.10.7

The compiler itself

Cabal

3.2.1.0

Dependency of ghc-pkg utility

Win32

2.6.2.1

Dependency of ghc library

array

0.5.4.0

Dependency of ghc library

base

4.14.3.0

Core library

binary

0.8.8.0

Dependency of ghc library

bytestring

0.10.12.0

Dependency of ghc library

containers

0.6.5.1

Dependency of ghc library

deepseq

1.4.4.0

Dependency of ghc library

directory

1.3.6.0

Dependency of ghc library

exceptions

0.10.4

Dependency of haskeline library

filepath

1.4.2.1

Dependency of ghc library

ghc-boot-th

8.10.7

Internal compiler library

ghc-boot

8.10.7

Internal compiler library

ghc-compact

0.1.0.0

Core library

ghc-heap

8.10.7

GHC heap-walking library

ghc-prim

0.6.1

Core library

ghci

8.10.7

The REPL interface

haskeline

0.8.2

Dependency of ghci executable

hpc

0.6.1.0

Dependency of hpc executable

integer-gmp

1.0.3.0

Core library

libiserv

8.10.7

Internal compiler library

mtl

2.2.2

Dependency of Cabal library

parsec

3.1.14.0

Dependency of Cabal library

pretty

1.1.3.6

Dependency of ghc library

process

1.6.13.2

Dependency of ghc library

stm

2.5.0.1

Dependency of haskeline library

template-haskell

2.16.0.0

Core library

terminfo

0.4.1.4

Dependency of haskeline library

text

1.2.4.1

Dependency of Cabal library

time

1.9.3

Dependency of ghc library

transformers

0.5.6.2

Dependency of ghc library

unix

2.7.2.2

Dependency of ghc library

xhtml

3000.2.2.1

Dependency of haddock executable