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diff --git a/docs/users_guide/9.2.4-notes.rst b/docs/users_guide/9.2.4-notes.rst new file mode 100644 index 0000000000..210adda826 --- /dev/null +++ b/docs/users_guide/9.2.4-notes.rst @@ -0,0 +1,141 @@ +.. _release-9-2-4: + +Version 9.2.4 +============== + +The significant changes to the various parts of the compiler are listed in the +following sections. + +The :ghc-flag:`LLVM backend <-fllvm>` of this release is to be used with LLVM +9, 10, 11, or 12. + +Compiler +-------- + +- Add the :extension:`DeepSubsumption` language extension which reverses the + effects of the `Simplified Subsumption Proposal`_ introduced in GHC 9.0. This + is an attempt to make GHC 9.2.4 more backwards compatible with GHC 8.10 and + eases migration for users who depended on this feature. + + This extension is enabled by default with the :extension:`Haskell2010` + and :extension:`Haskell98` languages but disabled with the :extension:`GHC2021` + language originally introduced in GHC 9.2.1. + + See the `Deep Subsumption Proposal`_ for more details. + +.. _Simplified Subsumption Proposal: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0511-deep-subsumption.rst +.. _Deep Subsumption Proposal: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0511-deep-subsumption.rst + +- The flag ``-ddump-llvm`` doesn't imply ``-fllvm`` any more (:ghc-ticket:`21776`). + +- Fix a compiler panic due to a bug in the simplifier (:ghc-ticket:`21694`). + +- Fix a bug where the flag ``Werror=unrecognised-warning-flags`` did not behave as expected (:ghc-ticket:`21682`). + +- Fix miscompilations on AArch64 (:ghc-ticket:`21624`, :ghc-ticket:`21773`, :ghc-ticket:`20735`). + +- Fix a miscompilation bug that manifests due to improper handling of name shadowing during + common subexpression elimination (:ghc-ticket:`21685`). + +- Fix a space leak that may manifest using the ``extendMG`` function (:ghc-ticket:`21818`). + +- Ensure types from record dot syntax are stored in the HIE file AST (:ghc-ticket:`21797`). + +- Fix a compiler panic when importing "wrapper" with ``-XCApiFFI`` (:ghc-ticket:`20272`). + +- Enable ``-Wunicode-bidirectional-format-characters`` by default. This was meant to be enabled previously + but was not due to a botched backport (:ghc-ticket:`21865`). + +Runtime system +-------------- + +- Fix segfaults that may arise due to a bug in the implementation of the + ``keepAlive#`` primop. This may regress performance for certain programs which + use this primop or functions which use the primop, such as ``withForeignPtr``. + These regressions are mostly small, but can be larger in certain edge cases. + Judicious use of ``unsafeWithForeignPtr`` when its argument is known + not to statically diverge can mitigate these in many cases. It is our + judgement that the critical correctness issues justify the regression in + performance and that it is important to get a release out with the fix while we + work on a better approach which will improve performance for future releases + (:ghc-ticket:`21708`). + +- Fix a segfault that may arise using LDV profiling (:ghc-ticket:`21880`). + +- Fix a bug in the nonmoving GC which resulted in segfaults due to early GC (:ghc-ticket:`21885`). + +- Fix accounting for copied bytes during sequential garbage collections (:ghc-ticket:`21745`). + +- Allow passing``-po`` flag to set output during non-profiled builds (:ghc-ticket:`21445`). + +- Respect the ``-po`` flag to set output while heap profiling (:ghc-ticket:`21446`). + +GHCi +---- + +- Allow CApi FFI calls in GHCi (:ghc-ticket:`7388`). + +- Fix behaviour of Ctrl-C on Windows in GHCi (:ghc-ticket:`21889`). + +Core libraries +-------------- + +- Bump ``base`` to 4.16.3.0. + +- Ensure ``hGetBufNonBlocking`` doesn't block on Windows (:ghc-ticket:`21665`). + +Build system and packaging +-------------------------- + +- Don't override linker on Darwin during ``configure`` (:ghc-ticket:`21712`). + +- Fix a hadrian bug to do with building profiled executables without corresponding libraries (:ghc-ticket:`19624`). + +- Fix a panic on FreeBSD when building with hadrian due to incorrect arch triple (:ghc-ticket:`15718`). + + +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: Dependency of ``ghc`` library + libraries/Cabal/Cabal/Cabal.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 + 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/libiserv/libiserv.cabal: Internal compiler 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 + + |