GHC 8.2.1 is available

Ben Gamari - 2017-07-23

= The Glasgow Haskell Compiler – version 8.2.1 =

The GHC developers are very happy to announce the long-awaited 8.2.1 release of Glasgow Haskell Compiler. Binary and source distributions can be found at

This is the second release in the 8.0 series. As such, the focus of this release is performance, stability, and consolidation. Consequently numerous cleanups can be seen throughout the compiler including,

  • Significant improvements in compiler performance

  • More robust support for levity polymorphism

  • Reliable DWARF debugging information

  • Improved runtime system performance on NUMA systems

  • Retooling of the cost-center profiler, including support for live streaming of profile data via the GHC event log

  • Interface file determinism

  • More robust treatment of join points, enabling significantly better code generation in many cases

  • Numerous improvements in robustness on Windows

  • and the resolution of over 500 other tickets

In addition, there are a number of new features,

  • A new, more type-safe type reflection mechanism

  • The long-awaited Backpack module system

  • Deriving strategies to disambiguate between GHC’s various instance deriving mechanisms

  • Unboxed sum types, for efficient unpacked representation of sum data types

  • Compact regions, allowing better control over garbage collection in the presence of large heaps containing many long-lived objects.

  • Colorful messages and caret diagnostics for more legible errors

A more thorough list of the changes in this release can be found in the release notes.

There are a few changes in release-engineering that should be noted,

  • Binary distributions for 32-bit CentOS 6.7 have been dropped. Moreover, there are no dedicated CentOS 7.0 distributions as CentOS 7 can use can use Debian 8 binaries. If you would like us to continue to produce 32-bit CentOS 6.7 distributions please let us know.

  • GHC HQ now builds FreeBSD and OpenBSD distributions for amd64; this comes after many years of these distributions being faithfully provided by Karel Gardas and Pali Gabor Janos, who we should heartily thank for their contributions.

GHC HQ building these distributions ourselves will allow us to more quickly ship distributions to users by eliminating the need for a long lag time between source release availability and having all binary distributions available.

  • There is a technology-preview of an AArch64 Linux binary distribution, as well as an ARM Linux build. AArch64 support is quite preliminary but should be stable in 8.4 thanks to further linker fixes by Moritz Angerman. ARM should be stable.

  • GHC now tries to use the gold and lld linkers by default. These linkers are significantly faster than the BFD linker implementation that most Linux distributions use by default. If gold or lld are not available GHC will use the system’s default linker. GHC can be forced to use the default linker by passing –disable-ld-override to configure.

This release has been the result of over a year of hard work by over 150 code contributors. Thanks to everyone who has helped in writing patches, testing, reporting bugs, and offering feedback over the last year.

This release cycle was admittedly quite drawn out, significantly longer than expected or desired. While we are confident that the result is worth the wait, we have been steadily working on infrastructure which should help shrink future release cycles and give us better testing between releases. More details on this coming soon.

As always, let us know if you encounter trouble.

How to get it

Both the source tarball and binary distributions for a wide variety of platforms are available here.


Haskell is a standard lazy functional programming language.

GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating efficient code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces. GHC is distributed under a BSD-style open source license.

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