-

-Language

-~~~~~~~~

-

-- Fix a bug introduced in GHC 9.10 where GHC would erroneously accept infix uses

-  of promoted data constructors without enabling :extension:`DataKinds`. As a

-  result, you may need to enable :extension:`DataKinds` in code that did not

-  previously require it.

-- ``Type`` and ``Constraint`` are now (at last) completely distinct types, just as much

-  as ``Int`` and ``Bool``.  For example, you can now

-  write::

-    type family F a

-    type instance F Type = Int

-    type instance F Constraint = Bool

-  which was previously rejected with "Conflicting family instance declarations".

-- The extension :extension:`ExplicitNamespaces` now allows namespace-specified

-  wildcards ``type ..`` and ``data ..`` in import and export lists.

-Compiler

-~~~~~~~~

-- Code coverage's (:ghc-flag:`-fhpc`) treatment of record fields now extends

-  beyond record fields accessed via :extension:`RecordWildCards` and

-  :extension:`NamedFieldPuns`, and also handles access to nested record fields.

-  That is, in a pattern such as ``Foo{bar = Bar{baz = b}}`` both ``bar`` and

-  ``baz`` will now be marked as covered if ``b`` is evaluated. Note that this

-  currently only works when record fields (or values contained within them) are

-  bound to variables. The very similar pattern ``Foo{bar = Bar{baz = 42}}``

-  will will not yet mark ``bar`` or ``baz`` as covered.

-- Pattern synonyms can now be suggested as valid hole fits (except, of course,

-  if they are unidirectional).

-- GHC uses the information from the definition of a *closed* type family to

-  generate some extra functional dependencies for type equalities involving

-  that type family. As a consequence:

-  * typechecking will succeed a bit more often (see :ghc-ticket:`23162`)

-  * pattern-match incompleteness checking is a bit smarter, giving fewer false warnings (see :ghc-ticket:`#22652`)

-- When multiple ``-msse*`` flags are given, the maximum version takes effect.

-  For example, ``-msse4.2 -msse2`` is now equivalent to ``-msse4.2``.

-  Previously, only the last flag took effect.

-- Some x86 architecture flags now imply other flags.

-  For example, :ghc-flag:`-mavx` now implies :ghc-flag:`-msse4.2`,

-  and :ghc-flag:`-mavx512f` now implies :ghc-flag:`-mfma`

-  in addition to :ghc-flag:`-mavx2`.

-  Refer to the users' guide for more details about each individual flag.

-- Add a new `poll` I/O manager, based on the classic unix `poll()` API. It is

-  available in the single-threaded RTS on posix platforms. The `select` I/O

-  manager remains the default for this combination for now, but this default

-  may change in future releases. The new I/O manager can be selected via the

-  runtime flag :rts-flag:`--io-manager=(name)`.

-

-  Compared to the `select` I/O manager, this one has slightly less severe

-  restrictions on the number of sockets/pipes that can be waited on, though

-  it still scales poorly for waiting on socket/pipe readiness. It does however

-  scale much better for thread timers (such as `threadDelay`), and improves

-  timer precision on 32bit Linux and 32bit FreeBSD from milliseconds to

-  microseconds.

-

-  This I/O manager introduces new infrastructure for I/O managers that is

-  intended to be used in future for a new generation of in-RTS I/O managers,

-  using more scalable platform-specific APIs (such as epoll, io_uring and

-  kqueue). This first one, based on `poll()`, is merely intended to be

-  portable.

-

-Cmm

-~~~

-

-``base`` library

-~~~~~~~~~~~~~~~~

-

-- Updated to `Unicode 17.0.0

-  <https://www.unicode.org/versions/Unicode17.0.0>`_.

-

-``ghc-prim`` library

-~~~~~~~~~~~~~~~~~~~~

-``ghc-experimental`` library

-~~~~~~~~~~~~~~~~~~~~~~~~~~~~

-

-- New SIMD primops for bitwise logical operations on 128-wide vectors.

-``template-haskell`` library

-- We have added the ``addDependentDirectory`` function to match

-  ``addDependentFile``, which adds a directory to the list of dependencies that

-  the recompilation checker will look at to determine if a module needs to be

-  recompiled.

-

-

-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:               Dependency of ``ghc`` library

-    libraries/Cabal/Cabal/Cabal.cabal:                   Dependency of ``ghc-pkg`` utility

-    libraries/Cabal/Cabal-syntax/Cabal-syntax.cabal:     Dependency of ``ghc-pkg`` utility

-    libraries/containers/containers/containers.cabal:    Dependency of ``ghc`` library

-    libraries/deepseq/deepseq.cabal:                     Dependency of ``ghc`` library

-    libraries/directory/directory.cabal:                 Dependency of ``ghc`` library

-    libraries/exceptions/exceptions.cabal:               Dependency of ``ghc`` and ``haskeline`` 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-boot-th/ghc-boot-th.cabal:             Internal compiler library

-    libraries/ghc-compact/ghc-compact.cabal:             Core library

-    libraries/ghc-heap/ghc-heap.cabal:                   GHC heap-walking library

-    libraries/ghc-prim/ghc-prim.cabal:                   Core library

-    utils/haddock/haddock-api/haddock-api.cabal:         Dependency of ``haddock`` executable

-    utils/haddock/haddock-library/haddock-library.cabal: Dependency of ``haddock`` executable

-    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/pretty/pretty.cabal:                       Dependency of ``ghc`` library

-    libraries/process/process.cabal:                     Dependency of ``ghc`` library

-    libraries/stm/stm.cabal:                             Dependency of ``haskeline`` library

-    libraries/template-haskell/template-haskell.cabal:   Core library

-    libraries/terminfo/terminfo.cabal:                   Dependency of ``haskeline`` 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

-    libraries/os-string/os-string.cabal:                 Dependency of ``filepath`` library

-    libraries/file-io/file-io.cabal:                     Dependency of ``directory`` library

-    RtsFlags.TraceFlags.eventlogFlushTime = 0;