GHC 9.0.1 released

The GHC team is very pleased to announce the availability of GHC 9.0.1.
Source and binary distributions are available at the usual

In addition to numerous bug fixes, GHC 9.0.1 will bring a number of new

  • A first cut of the new LinearTypes language extension, allowing use
    of linear function syntax and linear record fields.

  • A new bignum library, ghc-bignum, improving portability and allowing GHC
    to be more easily used with integer libraries other than GMP.

  • Improvements in code generation, resulting in considerable
    runtime performance improvements in some programs.

  • Improvements in pattern-match checking, allowing more precise
    detection of redundant cases and reduced compilation time.

  • Implementation of the “simplified subsumption” proposal
    simplifying the type system and paving the way for QuickLook
    impredicativity in GHC 9.2.

  • Implementation of the QualifiedDo extension, allowing more
    convenient overloading of do syntax.

  • An experimental new IO manager implementation for Windows platforms, both
    improving performance and fixing many of the quirks with the old manager built
    on POSIX-emulation.

  • Improvements in compilation time.

And many more. See the release notes for a full accounting of the
changes in this release.

As always, feel free to report any issues you encounter via