GHC 8.4.2 released

The GHC team is pleased to announce the availability of GHC 8.4.2. The source distribution, binary distributions, and documentation for this release are available at

This release is a bug-fix release, fixing numerous regressions and bugs present in GHC 8.4.1. These include:

  • A regression resulting in some uses of Control.Exception.evaluate to be inappropriately optimised away (see #13930)
  • A regression resulting in segmentation faults of programs compiled with profiling (#14705)
  • A bug causing runtime system panics while running programs with retainer profiling (#14947)
  • The configure scripts now accepts a --disable-dtrace option, again allowing GHC to be bootstrapped on FreeBSD (#15040)
  • The version number of the base package has been bumped to to reflect the addition of the GHC.IO.FixIOException type. This interface was added in 8.4.1 but the version bump was missed due to an oversight.
  • Support for DWARF debug information has been significantly improved (#14894, #14779)

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

Thanks to everyone who has contributed to developing, documenting, and testing this release!

As always, let us know if you encounter trouble.

How to get it

This release can be downloaded from

For older versions see

We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place.


Haskell is a standard lazy functional programming language.

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  • Posted: 2018-04-20 00:03 (Updated: 2018-04-20 13:40)
  • Author: Ben Gamari
  • Categories: release


1. takenobu -- 2018-04-20 11:53

Please fix the link in the session of "How to get":

-    ​
2. takenobu -- 2018-04-20 23:18

Please fix the link in the session of "How to get":

Thanks for the fix.