.. _release-8-4-4:

Release notes for version 8.4.4
===============================

Highlights
----------

This is a bug-fix release resolving several regressions introduced in 8.4.1.

The highlights, since the 8.4.3 release, are:

- A bug which could result in memory unsafety with certain uses of ``touch#``
  has been resolved. (:ghc-ticket:`14346`)

- A compiler panic triggered by some GADT record updates has been fixed
  (:ghc-ticket:`15499`)

- The ``text`` library has been updated, fixing several serious bugs in the
  version shipped with GHC 8.4.3 (see `#227
  <https://github.com/haskell/text/issues/227>`_,
  `#221 <https://github.com/haskell/text/issues/221>`_, and `#197
  <https://github.com/haskell/text/issues/197>`_.

- A serious code generation bug in the LLVM code generation, potentially resulting
  in incorrect evaluation of floating point expressions, has been fixed
  (:ghc-ticket:`14251`)


Full details
------------

In addition to the highlights listed above, this release resolves a number of
other issues, described below.

Compiler
~~~~~~~~

- A compiler panic triggered by case alternatives matching on invalid tags
  returned by ``dataToTag#``, has been fixed (:ghc-ticket:`15436`)

- Package environments can now be explicitly disabled using the new
  ``-package-env -`` flag. (:ghc-ticket:`13753`)

Runtime system
~~~~~~~~~~~~~~

No changes.

Template Haskell
~~~~~~~~~~~~~~~~

No changes.

``ghc`` library
~~~~~~~~~~~~~~~

No changes.

``base`` library
~~~~~~~~~~~~~~~~

- Version bumped to 4.11.1.0 to account for the addition of
  ``GHC.IO.FixIOException``

- Add the ``readFieldHash`` function to ``GHC.Read`` which behaves like
  ``readField``, but for a field that ends with a ``#`` symbol.

``integer-gmp`` library
~~~~~~~~~~~~~~~~~~~~~~~

No changes.

Build system
~~~~~~~~~~~~

No changes.

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.

.. ghc-package-list::

    libraries/array/array.cabal:             Dependency of ``ghc`` library
    libraries/base/base.cabal:               Core library
    libraries/binary/binary.cabal:           Dependency of ``ghc`` library
    libraries/bytestring/bytestring.cabal:   Deppendency of ``ghc`` library
    libraries/Cabal/Cabal/Cabal.cabal:       Dependency of ``ghc-pkg`` utility
    libraries/containers/containers.cabal:   Dependency of ``ghc`` library
    libraries/deepseq/deepseq.cabal:         Dependency of ``ghc`` library
    libraries/directory/directory.cabal:     Dependency of ``ghc`` library
    libraries/filepath/filepath.cabal:       Dependency of ``ghc`` library
    compiler/ghc.cabal:                      The compiler itself
    libraries/ghci/ghci.cabal:               The REPL interface
    libraries/ghc-boot/ghc-boot.cabal:       Internal compiler library
    libraries/ghc-compact/ghc-compact.cabal: Core library
    libraries/ghc-prim/ghc-prim.cabal:       Core library
    libraries/haskeline/haskeline.cabal:     Dependency of ``ghci`` executable
    libraries/hpc/hpc.cabal:                 Dependency of ``hpc`` executable
    libraries/integer-gmp/integer-gmp.cabal: Core library
    libraries/mtl/mtl.cabal:                 Dependency of ``Cabal`` library
    libraries/parsec/parsec.cabal:           Dependency of ``Cabal`` library
    libraries/process/process.cabal:         Dependency of ``ghc`` library
    libraries/template-haskell/template-haskell.cabal:     Core library
    libraries/text/text.cabal:               Dependency of ``Cabal`` library
    libraries/time/time.cabal:               Dependency of ``ghc`` library
    libraries/transformers/transformers.cabal: Dependency of ``ghc`` library
    libraries/unix/unix.cabal:               Dependency of ``ghc`` library
    libraries/Win32/Win32.cabal:             Dependency of ``ghc`` library
    libraries/xhtml/xhtml.cabal:             Dependency of ``haddock`` executable
