Mirror of the Glasgow Haskell Compiler. Patches are best submitted to GHC's GitLab instance (https://gitlab.haskell.org/), bugs and feature-requests are best filed to GHC's Trac (https://ghc.haskell.org/trac/ghc), or sent to the mailing list (ghc-devs@haskell.org). First time contributors are encouraged to get started by just sending a Pull Requ…
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simonpj and Marge Bot Fix bogus worker for newtypes
The "worker" for a newtype is actually a function
with a small (compulsory) unfolding, namely a cast.

But the construction of this function was plain wrong
for newtype /instances/; it cast the arguemnt to the
family type rather than the representation type.

This never actually bit us because, in the case of a
family instance, we immediately cast the result to
the family type.  So we get
   \x. (x |> co1) |> co2

where the compositio of co1 and co2 is ill-kinded.
However the optimiser (even the simple optimiser)
just collapsed those casts, ignoring the mis-match
in the middle, so we never saw the problem.

Trac #16191 is indeed a dup of #16141; but the resaon
these tickets produce Lint errors is not the unnecessary
forcing; it's because of the ill-typed casts.

This patch fixes the ill-typed casts, properly.  I can't
see a way to trigger an actual failure prior to this
patch, but it's still wrong wrong wrong to have ill-typed
casts, so better to get rid of them.
Latest commit a5373c1 Jan 16, 2019
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.arc-linters Bump arcanist-external-json-linter submodule Oct 19, 2017
.circleci CircleCI: Fix check for git push retry limit. Dec 21, 2018
.gitlab gitlab: Add merge request template Jan 21, 2019
bindisttest Rework CC/CC_STAGE0 handling in `configure.ac` Apr 16, 2016
compiler Fix bogus worker for newtypes Jan 22, 2019
distrib distrib/configure: Set RanlibCmd Nov 23, 2018
docs doc: behaviour of +RTS -h depends on profiling Jan 16, 2019
driver driver/utils/dynwrapper.c: Remove unused variable Feb 25, 2018
ghc Introduce ghci command wrapper Jan 16, 2019
hadrian Make sure 'haddock' package also copies resources Jan 16, 2019
includes Documentation for StgRetFun Jan 16, 2019
libffi-tarballs @ 96d0280 Bump libffi-tarballs submodule Oct 2, 2017
libffi No libffi docs Oct 3, 2017
libraries Add support for ASM foreign files (.s) in TH (#16180) Jan 21, 2019
mk Remove warnings-silencing flags for code generated by Alex Nov 22, 2018
nofib @ f87d446 Bump nofib submodule Dec 3, 2018
rts Extend linker-script workaround to work with musl libc Jan 21, 2019
rules Fix bindist for ghci library Jan 6, 2019
testsuite Add support for ASM foreign files (.s) in TH (#16180) Jan 21, 2019
utils [T16199] Adds a verify-packages script Jan 20, 2019
.appveyor.sh Run tests after artifact collection Apr 7, 2018
.arcconfig arcconfig: Set project ruleset to use master merge-base by default Jul 20, 2017
.arclint Use python3 for linters Dec 23, 2016
.ghcid Add a script for running a ghci that can load and run ghc Jul 27, 2018
.gitignore Use autoconf to generate version numbers for libiserv and friends Nov 26, 2018
.gitlab-ci.yml gitlab-ci: Cleanup Windows builds Jan 14, 2019
.gitmodules Remove Hadrian submodule Oct 23, 2018
.mailmap Update .mailmap [skip ci] Aug 20, 2018
.travis.yml Attempt to fix travis build Jul 12, 2018
ANNOUNCE Update ANNOUNCE Nov 22, 2017
CODEOWNERS Add CODEOWNERS Jan 21, 2019
HACKING.md Add info about Github pull requests. Oct 25, 2017
INSTALL.md Fix some broken links (#15733) Oct 25, 2018
LICENSE Reorganisation of the source tree Apr 7, 2006
MAKEHELP.md Rewrite boot in Python Oct 2, 2017
Makefile Improve diagnostic when using `make fast` in top directory Oct 28, 2018
README.md Fix README Nov 23, 2017
Vagrantfile vagrant: move files around Jul 20, 2014
aclocal.m4 configure: introduce HAPPY and ALEX vars and deprecate --with-ghc in … Jan 1, 2019
appveyor.yml Full AppVeyor build with tests Mar 29, 2018
boot Cleanup boot and validate Oct 15, 2018
build.nix.sh Disable Shake Lint by default. Jan 16, 2019
config.guess Update autoconf scripts Jul 23, 2017
config.sub Update autoconf scripts from correct source May 12, 2017
configure.ac configure: introduce HAPPY and ALEX vars and deprecate --with-ghc in … Jan 1, 2019
ghc.mk Support printing `integer-simple` Integers in GHCi Jan 16, 2019
install-sh Update aux files `config.{guess,sub}` and `install-sh` Nov 7, 2013
llvm-passes Revert "Multiple fixes / improvements for LLVM backend" Nov 7, 2018
llvm-targets llvm-targets: Add amd64-unknown-freebsd triple Dec 14, 2018
packages Remove random submodule Jul 14, 2018
settings.in Use ar for -staticlib Sep 13, 2017
validate Cleanup boot and validate Oct 15, 2018

README.md

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:

    ghc-<version>-src.tar.bz2

which contains GHC itself and the "boot" libraries.

  1. Check out the source code from git

    $ git clone --recursive git://git.haskell.org/ghc.git
    

Note: cloning GHC from Github requires a special setup. See Getting a GHC repository from Github.

See the GHC team's working conventions regarding how to contribute a patch to GHC. First time contributors are encouraged to get started by just sending a Pull Request.

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 Sphinx and Xelatex (only for PDF output).

Quick start: the following gives you a default build:

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

On Windows, you need an extra repository containing some build tools. These can be downloaded for you by configure. This only needs to be done once by running:

$ ./configure --enable-tarballs-autodownload

(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 ./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.md.

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 HACKING.md 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!