├── cabal.project
├── .ghci
├── Setup.lhs
├── cabal.haskell-ci
├── .gitignore
├── README.markdown
├── .vim.custom
├── CHANGELOG.markdown
├── LICENSE
├── src
    └── Data
    │   └── Void
    │       └── Unsafe.hs
├── void.cabal
├── src-old
    └── Data
    │   └── Void.hs
└── .github
    └── workflows
        └── haskell-ci.yml


/cabal.project:
--------------------------------------------------------------------------------
1 | packages: .
2 | 


--------------------------------------------------------------------------------
/.ghci:
--------------------------------------------------------------------------------
1 | :set -isrc -idist/build/autogen -optP-include -optPdist/build/autogen/cabal_macros.h
2 | 


--------------------------------------------------------------------------------
/Setup.lhs:
--------------------------------------------------------------------------------
1 | #!/usr/bin/runhaskell
2 | > module Main (main) where
3 | 
4 | > import Distribution.Simple
5 | 
6 | > main :: IO ()
7 | > main = defaultMain
8 | 


--------------------------------------------------------------------------------
/cabal.haskell-ci:
--------------------------------------------------------------------------------
1 | no-tests-no-benchmarks: False
2 | unconstrained:          False
3 | -- irc-channels:           irc.freenode.org#haskell-lens
4 | irc-if-in-origin-repo:  True
5 | 


--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
 1 | *#
 2 | *.hi
 3 | *.o
 4 | *~
 5 | .*.swo
 6 | .*.swp
 7 | .swp
 8 | .DS_Store
 9 | TAGS
10 | _darcs
11 | dist
12 | docs
13 | tags
14 | wiki
15 | wip
16 | dist-newstyle/
17 | .stack-work/
18 | cabal-dev
19 | *.chi
20 | *.chs.h
21 | *.dyn_o
22 | *.dyn_hi
23 | .hpc
24 | .hsenv
25 | .cabal-sandbox/
26 | cabal.sandbox.config
27 | *.prof
28 | *.aux
29 | *.hp
30 | *.eventlog
31 | cabal.project.local
32 | cabal.project.local~
33 | .HTF/
34 | .ghc.environment.*
35 | 


--------------------------------------------------------------------------------
/README.markdown:
--------------------------------------------------------------------------------
 1 | void
 2 | ====
 3 | 
 4 | [![Hackage](https://img.shields.io/hackage/v/void.svg)](https://hackage.haskell.org/package/void) [![Build Status](https://github.com/ekmett/void/workflows/Haskell-CI/badge.svg)](https://github.com/ekmett/void/actions?query=workflow%3AHaskell-CI)
 5 | 
 6 | This package provides a canonical 'uninhabited' data type for Haskell. This arises in a surprisingly wide array of situations in practice.
 7 | 
 8 | Contact Information
 9 | -------------------
10 | 
11 | Contributions and bug reports are welcome!
12 | 
13 | Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net.
14 | 
15 | -Edward Kmett
16 | 


--------------------------------------------------------------------------------
/.vim.custom:
--------------------------------------------------------------------------------
 1 | " Add the following to your .vimrc to automatically load this on startup
 2 | 
 3 | " if filereadable(".vim.custom")
 4 | "     so .vim.custom
 5 | " endif
 6 | 
 7 | function StripTrailingWhitespace()
 8 |   let myline=line(".")
 9 |   let mycolumn = col(".")
10 |   silent %s/  *$//
11 |   call cursor(myline, mycolumn)
12 | endfunction
13 | 
14 | " enable syntax highlighting
15 | syntax on
16 | 
17 | " search for the tags file anywhere between here and /
18 | set tags=TAGS;/
19 | 
20 | " highlight tabs and trailing spaces
21 | set listchars=tab:‗‗,trail:‗
22 | set list
23 | 
24 | " f2 runs hasktags
25 | map <F2> :exec ":!hasktags -x -c --ignore src"<CR><CR>
26 | 
27 | " strip trailing whitespace before saving
28 | " au BufWritePre *.hs,*.markdown silent! cal StripTrailingWhitespace()
29 | 
30 | " rebuild hasktags after saving
31 | au BufWritePost *.hs silent! :exec ":!hasktags -x -c --ignore src"
32 | 


--------------------------------------------------------------------------------
/CHANGELOG.markdown:
--------------------------------------------------------------------------------
 1 | 0.7.4 [2025.12.08]
 2 | ------------------
 3 | * Drop support for pre-8.0 versions of GHC.
 4 | 
 5 | 0.7.3 [2019.05.10]
 6 | ------------------
 7 | * Backport the `Lift Void` instance introduced in `template-haskell-2.15.0.0`.
 8 | 
 9 | 0.7.2
10 | -----
11 | * Only depend on `deepseq`, `hashable`, and `semigroups` if using GHC 7.8 or earlier.
12 | * Cleaned up spurious "redundant constraint" warnings on GHC 8+
13 | 
14 | 0.7.1
15 | -----
16 | * Support `semigroups` 0.17 on older GHCs
17 | * Backported `NFData`'s `semigroup` instance to older GHCs.
18 | 
19 | 0.7
20 | ---
21 | * adapt to `Data.Void` being moved into `base-4.8`
22 | * `vacuousM` removed
23 | 
24 | 0.6
25 | ---
26 | * `instance Exception Void`
27 | * `instance Generic Void`
28 | * `instance Hashable Void`
29 | 
30 | 0.5.12
31 | ------
32 | * Fixed compatibility with GHC 7.2 (#6)
33 | * Added `CHANGELOG.markdown` and `README.markdown`
34 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
 1 | Copyright 2015 Edward Kmett
 2 | 
 3 | All rights reserved.
 4 | 
 5 | Redistribution and use in source and binary forms, with or without
 6 | modification, are permitted provided that the following conditions
 7 | are met:
 8 | 
 9 | 1. Redistributions of source code must retain the above copyright
10 |    notice, this list of conditions and the following disclaimer.
11 | 
12 | 2. Redistributions in binary form must reproduce the above copyright
13 |    notice, this list of conditions and the following disclaimer in the
14 |    documentation and/or other materials provided with the distribution.
15 | 
16 | 3. Neither the name of the author nor the names of his contributors
17 |    may be used to endorse or promote products derived from this software
18 |    without specific prior written permission.
19 | 
20 | THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
21 | IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
22 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
23 | DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
24 | ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 | DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 | OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 | HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
28 | STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
29 | ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 | POSSIBILITY OF SUCH DAMAGE.
31 | 


--------------------------------------------------------------------------------
/src/Data/Void/Unsafe.hs:
--------------------------------------------------------------------------------
 1 | {-# LANGUAGE CPP #-}
 2 | #if !defined(SAFE) && defined(__GLASGOW_HASKELL__)
 3 | #define UNSAFE
 4 | {-# LANGUAGE Unsafe #-}
 5 | #endif
 6 | {-# OPTIONS_GHC -Wno-redundant-constraints #-} -- they aren't redundant!
 7 | -----------------------------------------------------------------------------
 8 | -- |
 9 | -- Copyright   :  (C) 2008-2015 Edward Kmett
10 | -- License     :  BSD-style (see the file LICENSE)
11 | --
12 | -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
13 | -- Stability   :  provisional
14 | -- Portability :  portable
15 | --
16 | ----------------------------------------------------------------------------
17 | module Data.Void.Unsafe
18 |   ( unsafeVacuous
19 |   , unsafeVacuousM
20 |   ) where
21 | 
22 | import Data.Void
23 | 
24 | #ifdef UNSAFE
25 | import Unsafe.Coerce
26 | #endif
27 | 
28 | -- | If 'Void' is uninhabited then any 'Functor' that holds only values of the type 'Void'
29 | -- is holding no values.
30 | --
31 | -- This is only safe for valid functors that do not perform GADT-like analysis on the argument.
32 | unsafeVacuous :: Functor f => f Void -> f a
33 | #ifdef UNSAFE
34 | unsafeVacuous = unsafeCoerce
35 | #else
36 | unsafeVacuous = fmap absurd
37 | #endif
38 | 
39 | -- | If 'Void' is uninhabited then any 'Monad' that holds values of type 'Void'
40 | -- is holding no values.
41 | --
42 | -- This is only safe for valid monads that do not perform GADT-like analysis on the argument.
43 | unsafeVacuousM :: Monad m => m Void -> m a
44 | #ifdef UNSAFE
45 | unsafeVacuousM = unsafeCoerce
46 | #else
47 | unsafeVacuousM m = m >>= return . absurd
48 | #endif
49 | 


--------------------------------------------------------------------------------
/void.cabal:
--------------------------------------------------------------------------------
 1 | name:          void
 2 | category:      Data Structures
 3 | version:       0.7.4
 4 | license:       BSD3
 5 | cabal-version: >= 1.10
 6 | license-file:  LICENSE
 7 | author:        Edward A. Kmett
 8 | maintainer:    Edward A. Kmett <ekmett@gmail.com>
 9 | stability:     portable
10 | homepage:      http://github.com/ekmett/void
11 | bug-reports:   http://github.com/ekmett/void/issues
12 | copyright:     Copyright (C) 2008-2015 Edward A. Kmett
13 | synopsis:      A Haskell 98 logically uninhabited data type
14 | description:   A Haskell 98 logically uninhabited data type, used to indicate that a given term should not exist.
15 | build-type:    Simple
16 | tested-with:   GHC==9.12.2
17 |              , GHC==9.10.3
18 |              , GHC==9.8.4
19 |              , GHC==9.6.6
20 |              , GHC==9.4.8
21 |              , GHC==9.2.8
22 |              , GHC==9.0.2
23 |              , GHC==8.10.7
24 |              , GHC==8.8.4
25 |              , GHC==8.6.5
26 |              , GHC==8.4.4
27 |              , GHC==8.2.2
28 |              , GHC==8.0.2
29 | 
30 | extra-source-files:
31 |   .ghci
32 |   .gitignore
33 |   .vim.custom
34 |   CHANGELOG.markdown
35 |   README.markdown
36 | 
37 | source-repository head
38 |   type: git
39 |   location: https://github.com/ekmett/void.git
40 | 
41 | flag safe
42 |   manual: True
43 |   default: False
44 | 
45 | library
46 |   default-language: Haskell98
47 |   hs-source-dirs: src
48 |   exposed-modules:
49 |     Data.Void.Unsafe
50 | 
51 |   build-depends: base >= 3 && < 10
52 | 
53 |   ghc-options: -Wall
54 | 
55 |   if flag(safe)
56 |     cpp-options: -DSAFE
57 | 


--------------------------------------------------------------------------------
/src-old/Data/Void.hs:
--------------------------------------------------------------------------------
  1 | {-# LANGUAGE CPP #-}
  2 | #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
  3 | {-# LANGUAGE Trustworthy #-}
  4 | #endif
  5 | 
  6 | #ifdef LANGUAGE_DeriveDataTypeable
  7 | {-# LANGUAGE DeriveDataTypeable #-}
  8 | #endif
  9 | 
 10 | #ifdef LANGUAGE_DeriveGeneric
 11 | {-# LANGUAGE DeriveGeneric #-}
 12 | {-# LANGUAGE StandaloneDeriving #-}
 13 | #endif
 14 | 
 15 | #ifndef MIN_VERSION_base
 16 | #define MIN_VERSION_base(x,y,z) 1
 17 | #endif
 18 | 
 19 | #ifndef MIN_VERSION_semigroups
 20 | #define MIN_VERSION_semigroups(x,y,z) 1
 21 | #endif
 22 | -----------------------------------------------------------------------------
 23 | -- |
 24 | -- Copyright   :  (C) 2008-2015 Edward Kmett
 25 | -- License     :  BSD-style (see the file LICENSE)
 26 | --
 27 | -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
 28 | -- Stability   :  provisional
 29 | -- Portability :  portable
 30 | --
 31 | ----------------------------------------------------------------------------
 32 | module Data.Void
 33 |   ( Void
 34 |   , absurd
 35 |   , vacuous
 36 |   , vacuousM
 37 |   ) where
 38 | 
 39 | import Control.DeepSeq (NFData(..))
 40 | import Control.Monad (liftM)
 41 | import Data.Ix
 42 | import Data.Hashable
 43 | import Data.Semigroup (Semigroup(..))
 44 | 
 45 | #ifdef LANGUAGE_DeriveDataTypeable
 46 | import Data.Data
 47 | #endif
 48 | 
 49 | #ifdef LANGUAGE_DeriveGeneric
 50 | import GHC.Generics
 51 | #endif
 52 | 
 53 | #if MIN_VERSION_base(4,0,0)
 54 | import Control.Exception
 55 | #endif
 56 | 
 57 | import Language.Haskell.TH.Syntax (Lift (..))
 58 | 
 59 | -- | A logically uninhabited data type.
 60 | #if __GLASGOW_HASKELL__ < 700
 61 | data Void = Void !Void
 62 | #else
 63 | newtype Void = Void Void
 64 | #endif
 65 | #ifdef LANGUAGE_DeriveDataTypeable
 66 |   deriving (Data, Typeable)
 67 | #endif
 68 | 
 69 | #ifdef LANGUAGE_DeriveGeneric
 70 | deriving instance Generic Void
 71 | #endif
 72 | 
 73 | instance Eq Void where
 74 |   _ == _ = True
 75 | 
 76 | instance Hashable Void where
 77 |   hashWithSalt _ = absurd
 78 | 
 79 | instance Ord Void where
 80 |   compare _ _ = EQ
 81 | 
 82 | instance Show Void where
 83 |   showsPrec _ = absurd
 84 | 
 85 | -- | Reading a 'Void' value is always a parse error, considering 'Void' as
 86 | -- a data type with no constructors.
 87 | instance Read Void where
 88 |   readsPrec _ _ = []
 89 | 
 90 | -- | Since 'Void' values logically don't exist, this witnesses the logical
 91 | -- reasoning tool of \"ex falso quodlibet\".
 92 | absurd :: Void -> a
 93 | absurd a = a `seq` spin a where
 94 |    spin (Void b) = spin b
 95 | 
 96 | -- | If 'Void' is uninhabited then any 'Functor' that holds only values of type 'Void'
 97 | -- is holding no values.
 98 | vacuous :: Functor f => f Void -> f a
 99 | vacuous = fmap absurd
100 | 
101 | -- | If 'Void' is uninhabited then any 'Monad' that holds values of type 'Void'
102 | -- is holding no values.
103 | vacuousM :: Monad m => m Void -> m a
104 | vacuousM = liftM absurd
105 | 
106 | instance Semigroup Void where
107 |   a <> _ = a
108 | #if MIN_VERSION_semigroups(0,17,0)
109 |   stimes _ a = a
110 | #else
111 |   times1p _ a = a
112 | #endif
113 | 
114 | instance Ix Void where
115 |   range _ = []
116 |   index _ = absurd
117 |   inRange _ = absurd
118 |   rangeSize _ = 0
119 | 
120 | #if MIN_VERSION_base(4,0,0)
121 | instance Exception Void
122 | #endif
123 | 
124 | -- | Defined as @'rnf' = 'absurd'@.
125 | instance NFData Void where
126 |   rnf = absurd
127 | 
128 | instance Lift Void where
129 |   lift = return . absurd
130 | 


--------------------------------------------------------------------------------
/.github/workflows/haskell-ci.yml:
--------------------------------------------------------------------------------
  1 | # This GitHub workflow config has been generated by a script via
  2 | #
  3 | #   haskell-ci 'github' '--config=cabal.haskell-ci' 'cabal.project'
  4 | #
  5 | # To regenerate the script (for example after adjusting tested-with) run
  6 | #
  7 | #   haskell-ci regenerate
  8 | #
  9 | # For more information, see https://github.com/haskell-CI/haskell-ci
 10 | #
 11 | # version: 0.19.20250917
 12 | #
 13 | # REGENDATA ("0.19.20250917",["github","--config=cabal.haskell-ci","cabal.project"])
 14 | #
 15 | name: Haskell-CI
 16 | on:
 17 |   - push
 18 |   - pull_request
 19 |   - merge_group
 20 | jobs:
 21 |   linux:
 22 |     name: Haskell-CI - Linux - ${{ matrix.compiler }}
 23 |     runs-on: ubuntu-24.04
 24 |     timeout-minutes:
 25 |       60
 26 |     container:
 27 |       image: buildpack-deps:jammy
 28 |     continue-on-error: ${{ matrix.allow-failure }}
 29 |     strategy:
 30 |       matrix:
 31 |         include:
 32 |           - compiler: ghc-9.12.2
 33 |             compilerKind: ghc
 34 |             compilerVersion: 9.12.2
 35 |             setup-method: ghcup
 36 |             allow-failure: false
 37 |           - compiler: ghc-9.10.3
 38 |             compilerKind: ghc
 39 |             compilerVersion: 9.10.3
 40 |             setup-method: ghcup
 41 |             allow-failure: false
 42 |           - compiler: ghc-9.8.4
 43 |             compilerKind: ghc
 44 |             compilerVersion: 9.8.4
 45 |             setup-method: ghcup
 46 |             allow-failure: false
 47 |           - compiler: ghc-9.6.6
 48 |             compilerKind: ghc
 49 |             compilerVersion: 9.6.6
 50 |             setup-method: ghcup
 51 |             allow-failure: false
 52 |           - compiler: ghc-9.4.8
 53 |             compilerKind: ghc
 54 |             compilerVersion: 9.4.8
 55 |             setup-method: ghcup
 56 |             allow-failure: false
 57 |           - compiler: ghc-9.2.8
 58 |             compilerKind: ghc
 59 |             compilerVersion: 9.2.8
 60 |             setup-method: ghcup
 61 |             allow-failure: false
 62 |           - compiler: ghc-9.0.2
 63 |             compilerKind: ghc
 64 |             compilerVersion: 9.0.2
 65 |             setup-method: ghcup
 66 |             allow-failure: false
 67 |           - compiler: ghc-8.10.7
 68 |             compilerKind: ghc
 69 |             compilerVersion: 8.10.7
 70 |             setup-method: ghcup
 71 |             allow-failure: false
 72 |           - compiler: ghc-8.8.4
 73 |             compilerKind: ghc
 74 |             compilerVersion: 8.8.4
 75 |             setup-method: ghcup
 76 |             allow-failure: false
 77 |           - compiler: ghc-8.6.5
 78 |             compilerKind: ghc
 79 |             compilerVersion: 8.6.5
 80 |             setup-method: ghcup
 81 |             allow-failure: false
 82 |           - compiler: ghc-8.4.4
 83 |             compilerKind: ghc
 84 |             compilerVersion: 8.4.4
 85 |             setup-method: ghcup
 86 |             allow-failure: false
 87 |           - compiler: ghc-8.2.2
 88 |             compilerKind: ghc
 89 |             compilerVersion: 8.2.2
 90 |             setup-method: ghcup
 91 |             allow-failure: false
 92 |           - compiler: ghc-8.0.2
 93 |             compilerKind: ghc
 94 |             compilerVersion: 8.0.2
 95 |             setup-method: ghcup
 96 |             allow-failure: false
 97 |       fail-fast: false
 98 |     steps:
 99 |       - name: apt-get install
100 |         run: |
101 |           apt-get update
102 |           apt-get install -y --no-install-recommends gnupg ca-certificates dirmngr curl git software-properties-common libtinfo5 libnuma-dev
103 |       - name: Install GHCup
104 |         run: |
105 |           mkdir -p "$HOME/.ghcup/bin"
106 |           curl -sL https://downloads.haskell.org/ghcup/0.1.50.1/x86_64-linux-ghcup-0.1.50.1 > "$HOME/.ghcup/bin/ghcup"
107 |           chmod a+x "$HOME/.ghcup/bin/ghcup"
108 |       - name: Install cabal-install
109 |         run: |
110 |           "$HOME/.ghcup/bin/ghcup" install cabal 3.16.0.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
111 |           echo "CABAL=$HOME/.ghcup/bin/cabal-3.16.0.0 -vnormal+nowrap" >> "$GITHUB_ENV"
112 |       - name: Install GHC (GHCup)
113 |         if: matrix.setup-method == 'ghcup'
114 |         run: |
115 |           "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
116 |           HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
117 |           HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
118 |           HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
119 |           echo "HC=$HC" >> "$GITHUB_ENV"
120 |           echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
121 |           echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
122 |         env:
123 |           HCKIND: ${{ matrix.compilerKind }}
124 |           HCNAME: ${{ matrix.compiler }}
125 |           HCVER: ${{ matrix.compilerVersion }}
126 |       - name: Set PATH and environment variables
127 |         run: |
128 |           echo "$HOME/.cabal/bin" >> $GITHUB_PATH
129 |           echo "LANG=C.UTF-8" >> "$GITHUB_ENV"
130 |           echo "CABAL_DIR=$HOME/.cabal" >> "$GITHUB_ENV"
131 |           echo "CABAL_CONFIG=$HOME/.cabal/config" >> "$GITHUB_ENV"
132 |           HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\d+)\.(\d+)\.(\d+)(\.(\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')
133 |           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
134 |           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
135 |           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
136 |           echo "HEADHACKAGE=false" >> "$GITHUB_ENV"
137 |           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
138 |         env:
139 |           HCKIND: ${{ matrix.compilerKind }}
140 |           HCNAME: ${{ matrix.compiler }}
141 |           HCVER: ${{ matrix.compilerVersion }}
142 |       - name: env
143 |         run: |
144 |           env
145 |       - name: write cabal config
146 |         run: |
147 |           mkdir -p $CABAL_DIR
148 |           cat >> $CABAL_CONFIG <<EOF
149 |           remote-build-reporting: anonymous
150 |           write-ghc-environment-files: never
151 |           remote-repo-cache: $CABAL_DIR/packages
152 |           logs-dir:          $CABAL_DIR/logs
153 |           world-file:        $CABAL_DIR/world
154 |           extra-prog-path:   $CABAL_DIR/bin
155 |           symlink-bindir:    $CABAL_DIR/bin
156 |           installdir:        $CABAL_DIR/bin
157 |           build-summary:     $CABAL_DIR/logs/build.log
158 |           store-dir:         $CABAL_DIR/store
159 |           install-dirs user
160 |             prefix: $CABAL_DIR
161 |           repository hackage.haskell.org
162 |             url: http://hackage.haskell.org/
163 |           EOF
164 |           cat >> $CABAL_CONFIG <<EOF
165 |           program-default-options
166 |             ghc-options: $GHCJOBS +RTS -M3G -RTS
167 |           EOF
168 |           cat $CABAL_CONFIG
169 |       - name: versions
170 |         run: |
171 |           $HC --version || true
172 |           $HC --print-project-git-commit-id || true
173 |           $CABAL --version || true
174 |       - name: update cabal index
175 |         run: |
176 |           $CABAL v2-update -v
177 |       - name: install cabal-plan
178 |         run: |
179 |           mkdir -p $HOME/.cabal/bin
180 |           curl -sL https://github.com/haskell-hvr/cabal-plan/releases/download/v0.7.3.0/cabal-plan-0.7.3.0-x86_64-linux.xz > cabal-plan.xz
181 |           echo 'f62ccb2971567a5f638f2005ad3173dba14693a45154c1508645c52289714cb2  cabal-plan.xz' | sha256sum -c -
182 |           xz -d < cabal-plan.xz > $HOME/.cabal/bin/cabal-plan
183 |           rm -f cabal-plan.xz
184 |           chmod a+x $HOME/.cabal/bin/cabal-plan
185 |           cabal-plan --version
186 |       - name: checkout
187 |         uses: actions/checkout@v5
188 |         with:
189 |           path: source
190 |       - name: initial cabal.project for sdist
191 |         run: |
192 |           touch cabal.project
193 |           echo "packages: $GITHUB_WORKSPACE/source/." >> cabal.project
194 |           cat cabal.project
195 |       - name: sdist
196 |         run: |
197 |           mkdir -p sdist
198 |           $CABAL sdist all --output-dir $GITHUB_WORKSPACE/sdist
199 |       - name: unpack
200 |         run: |
201 |           mkdir -p unpacked
202 |           find sdist -maxdepth 1 -type f -name '*.tar.gz' -exec tar -C $GITHUB_WORKSPACE/unpacked -xzvf {} \;
203 |       - name: generate cabal.project
204 |         run: |
205 |           PKGDIR_void="$(find "$GITHUB_WORKSPACE/unpacked" -maxdepth 1 -type d -regex '.*/void-[0-9.]*')"
206 |           echo "PKGDIR_void=${PKGDIR_void}" >> "$GITHUB_ENV"
207 |           rm -f cabal.project cabal.project.local
208 |           touch cabal.project
209 |           touch cabal.project.local
210 |           echo "packages: ${PKGDIR_void}" >> cabal.project
211 |           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "package void" >> cabal.project ; fi
212 |           if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project ; fi
213 |           if [ $((HCNUMVER >= 90400)) -ne 0 ] ; then echo "package void" >> cabal.project ; fi
214 |           if [ $((HCNUMVER >= 90400)) -ne 0 ] ; then echo "    ghc-options: -Werror=unused-packages" >> cabal.project ; fi
215 |           if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "package void" >> cabal.project ; fi
216 |           if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
217 |           cat >> cabal.project <<EOF
218 |           EOF
219 |           $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: any.$_ installed\n" unless /^(void)$/; }' >> cabal.project.local
220 |           cat cabal.project
221 |           cat cabal.project.local
222 |       - name: dump install plan
223 |         run: |
224 |           $CABAL v2-build $ARG_COMPILER $ARG_TESTS $ARG_BENCH --dry-run all
225 |           cabal-plan
226 |       - name: restore cache
227 |         uses: actions/cache/restore@v4
228 |         with:
229 |           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
230 |           path: ~/.cabal/store
231 |           restore-keys: ${{ runner.os }}-${{ matrix.compiler }}-
232 |       - name: install dependencies
233 |         run: |
234 |           $CABAL v2-build $ARG_COMPILER --disable-tests --disable-benchmarks --dependencies-only -j2 all
235 |           $CABAL v2-build $ARG_COMPILER $ARG_TESTS $ARG_BENCH --dependencies-only -j2 all
236 |       - name: build
237 |         run: |
238 |           $CABAL v2-build $ARG_COMPILER $ARG_TESTS $ARG_BENCH all --write-ghc-environment-files=always
239 |       - name: cabal check
240 |         run: |
241 |           cd ${PKGDIR_void} || false
242 |           ${CABAL} -vnormal check
243 |       - name: haddock
244 |         run: |
245 |           $CABAL v2-haddock --disable-documentation --haddock-all $ARG_COMPILER --with-haddock $HADDOCK $ARG_TESTS $ARG_BENCH all
246 |       - name: save cache
247 |         if: always()
248 |         uses: actions/cache/save@v4
249 |         with:
250 |           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
251 |           path: ~/.cabal/store
252 | 


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