users guide: initial commit of 8.4.3 release notes

docs/users_guide/8.4.3-notes.rst

+.. _release-8-4-3:
+
+Release notes for version 8.4.3
+===============================
+
+Highlights
+----------
+
+This is a bug-fix release resolving several regressions introduced in 8.4.1.
+
+The highlights, since the 8.4.2 release, are:
+
+- A bug (:ghc-ticket:`15068`) causing GHC to produce assembler that would be rejected by
+  some versions of GNU Binutils, has been fixed.
+
+- ``GHC.Compact.compact`` now properly handles ``SmallArray``\ s (:ghc-ticket:`13857`)
+
+- A bug (:ghc-ticket:`15038`) resulting in memory corruption and crashes in some uses of
+  unboxed sums has been fixed.
+
+- GHC now logs a message when an :ref:`environment file <package-environments>`
+  is loaded (:ghc-ticket:`15145`).
+
+Full details
+------------
+
+In addition to the highlights listed above, this release resolves a number of
+other issues, described below.
+
+Compiler
+~~~~~~~~
+
+No changes beyond those listed in Highlights.
+
+
+Runtime system
+~~~~~~~~~~~~~~
+
+- A bug causing aggressive potentially resulting in crashes when
+  (:rts-flag:`nursery chunks <-n ⟨size⟩>`) are used with a changing capability
+  count has been fixed.
+
+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