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This branch is 2 commits ahead, 1992 commits behind ghc:master

Module reexports, fixing #8407.

The general approach is to add a new field to the package database,
reexported-modules, which considered by the module finder as possible
module declarations.  Unlike declaring stub module files, multiple
reexports of the same physical package at the same name do not
result in an ambiguous import.

NB: When a reexport renames a module, that renaming is *not* accessible
from inside the package.  This is not so much a deliberate design choice
as for implementation expediency (reexport resolution happens only when
a package is in the package database.)

TODO: Error handling when there are duplicate reexports/etc is not very
well tested.

Signed-off-by: Edward Z. Yang <>
latest commit c112bb23db
@ezyang authored
Failed to load latest commit information.
bindisttest Follow-up to 32f41c7
compiler Module reexports, fixing #8407.
distrib Control CPP through settings file (#8683)
docs OK, I think we've finally solved granularity.
driver Update documentation
ghc Module reexports, fixing #8407.
includes rts: Fix #9003 with an annoying hack
libffi-tarballs @ a0088d1 Convert loose sub-repos into proper submodules (re #8545)
libffi Globally replace "" with ""
libraries Module reexports, fixing #8407.
mk Add BUILD_DPH variable to GHC build-system
nofib @ d98f703 Convert loose sub-repos into proper submodules (re #8545)
rts Acquire all_tasks_mutex in forkProcess
rules Handle base et al. specially in
testsuite Module reexports, fixing #8407.
utils Module reexports, fixing #8407.
vagrant Add a simplistic Vagrantfile with bootstrapping
.arcconfig Fix .arcconfig
.arclint arclint: update rules for xml files
.gitignore integer-gmp: tweak gitignore.
.gitmodules Add testsuite-related .gitignore files
.mailmap Update mailmap
ANNOUNCE Globally replace "" with ""
LICENSE Reorganisation of the source tree
MAKEHELP Globally replace "" with ""
Makefile Add travis-ci badge
Vagrantfile Add a simplistic Vagrantfile with bootstrapping
aclocal.m4 add support for x86_64-solaris2 platform
boot Replace all #!/usr/bin/perl with #!/usr/bin/env perl
config.guess Update aux files `config.{guess,sub}` and `install-sh`
config.sub Update aux files `config.{guess,sub}` and `install-sh` Fix windows breakage (fallout from 34f7e9a)
install-sh Update aux files `config.{guess,sub}` and `install-sh`
packages Declare official github home of libraries/unix Control CPP through settings file (#8683)
sync-all Fix “Checking for old .. repo” messages
tarballs Add tarball syncing to darcs-all
validate Add BUILD_DPH variable to GHC build-system

The Glasgow Haskell Compiler

Build Status

This is the source tree for GHC, a compiler and interactive environment for the Haskell functional programming language.

For more information, visit GHC's web site.

Information for developers of GHC can be found on the GHC Trac.

Getting the Source

There are two ways to get a source tree:

  1. Download source tarballs

    Download the GHC source distribution:


    which contains GHC itself and the "boot" libraries.

  2. Check out the source code from git

    First clone the GHC github read-only repository:

      $ git clone git://

    Then run the sync-all script in that repository to get the other repositories:

      $ cd ghc
      $ ./sync-all get

    This checks out the "boot" packages.

    DO NOT submit pull request directly to the github repo. See the GHC developer team's working conventions re contributing patches.

Building & Installing

For full information on building GHC, see the GHC Building Guide. Here follows a summary - if you get into trouble, the Building Guide has all the answers.

Before building GHC you may need to install some other tools and libraries. See, Setting up your system for building GHC.

NB. In particular, you need GHC installed in order to build GHC, because the compiler is itself written in Haskell. You also need Happy, Alex, and Cabal. For instructions on how to port GHC to a new platform, see the GHC Building Guide.

For building library documentation, you'll need Haddock. To build the compiler documentation, you need a good DocBook XML toolchain and dblatex.

Quick start: the following gives you a default build:

$ perl boot
$ ./configure
$ make         # can also say 'make -jX' for X number of jobs
$ make install

(NB: Do you have multiple cores? Be sure to tell that to make! This can save you hours of build time depending on your system configuration, and is almost always a win regardless of how many cores you have. As a simple rule, you should have about N+1 jobs, where N is the amount of cores you have.)

The perl boot step is only necessary if this is a tree checked out from git. For source distributions downloaded from GHC's web site, this step has already been performed.

These steps give you the default build, which includes everything optimised and built in various ways (eg. profiling libs are built). It can take a long time. To customise the build, see the file HACKING.

Once you have a build you need to keep it going. You need to keep all repos in sync with the sync-all script. To get the latest changes:

$ ./sync-all pull
$ ./sync-all get

Filing bugs and feature requests

If you've encountered what you believe is a bug in GHC, or you'd like to propose a feature request, please let us know! Submit a ticket in our bug tracker and we'll be sure to look into it. Remember: Filing a bug is the best way to make sure your issue isn't lost over time, so please feel free.

If you're an active user of GHC, you may also be interested in joining the glasgow-haskell-users mailing list, where developers and GHC users discuss various topics and hang out.

Hacking & Developing GHC

Once you've filed a bug, maybe you'd like to fix it yourself? That would be great, and we'd surely love your company! If you're looking to hack on GHC, check out the guidelines in the file in this directory - they'll get you up to speed quickly.

Contributors & Acknowledgements

GHC in its current form wouldn't exist without the hard work of its many contributors. Over time, it has grown to include the efforts and research of many institutions, highly talented people, and groups from around the world. We'd like to thank them all, and invite you to join!

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