2.5. Version 9.6.5

The significant changes to the various parts of the compiler are listed below. See the migration guide on the GHC Wiki for specific guidance on migrating programs to this release.

The LLVM backend of this release is to be used with LLVM 11, 12, 13, 14 or 15.

2.5.1. Significant Changes

Issues fixed in this release include:

2.5.1.1. Compiler

  • Disable -fasm-shortcutting with -O2 as it leads to unsound optimisations (:ghc-ticket:`24462).
  • Fix a typechecker bug resulting in TYPE and CONSTRAINT being apart (#24279).
  • Fix a bug resulting in incorrect runtime results due to a botched simplifier pass (#24295).
  • Assign correct source spans to nested documentation comments in the AST (#24378).
  • Fix a bug causing suboptimal error messages for certain invalid cyclic module graphs with hs-boot files (#24196, #24275).
  • Fix a bug resulting in infix (~) and (@) operators not being usable in TH quotes (#23748).
  • Fix a bug arising from incorrect parsing of paths containing spaces in the settings file (#24265).
  • Allow special pragmas to desugar correctly in a few more cases (#24370).

2.5.1.2. Runtime system

  • Fix an off-by-one while writing eventlogs (#24287).
  • Avoid segfaults with using -Dn with the non-moving collector (#24393).

2.5.1.3. Build system and packaging

  • Fix a bug resulting in the distributed hsc2hs wrapper using flags from the compiler build environment (#24050).
  • Better compatibility for newer alex versions in the configure script (#24302).
  • Handle autotools adding the -std flag to the CC/CXX variables (#24324).
  • Fix a typo in the configure script resulting in the target for the linker being set incorrectly when configuring a cross-compiler (#24414).
  • Do not override existing linker flags in FP_LD_NO_FIXUP_CHAINS.
  • Ensure the genapply program is built with the write constants when cross compiling (#24347).
  • Ensure we take LDFLAGS into account when configuring a linker (#24565).
  • Fix a segfault with the non-moving GC (#24492).

2.5.1.4. Core libraries

  • Bump base to 4.18.2.1
  • Bump filepath to 1.4.300.1
  • Bump directory to 1.3.8.4
  • Bump Cabal to 3.10.3.0
  • Bump process to 1.6.19.0
  • Bump libffi-tarballs to 3.4.6