I successfully installing ghc, cabal-install and stack using the "official repos" but I when subsequently using "sudo pacman -Syu" I was getting weird errors that "haddock" files were missing. So I removed all the haskell stuff I'd installed previously (I hope) and then updated my pacman.conf to add the haskell-core repo [1] and ran "sudo pacman -Syu" all seems to be OK. I then installed ghc and that seems fine: $ sudo pacman -Syu ghc :: Synchronizing package databases... core is up to date extra is up to date haskell-core is up to date community is up to date :: Starting full system upgrade... resolving dependencies... looking for conflicting packages... Packages (1) ghc-8.0.2-1 Total Installed Size: 1135.84 MiB :: Proceed with installation? [Y/n] (1/1) checking keys in keyring [#################################################################] 100% (1/1) checking package integrity [#################################################################] 100% (1/1) loading package files [#################################################################] 100% (1/1) checking for file conflicts [#################################################################] 100% (1/1) checking available disk space [#################################################################] 100% :: Processing package changes... (1/1) installing ghc [#################################################################] 100% :: Running post-transaction hooks... (1/2) Rebuild Haskell doc index (2/2) Arming ConditionNeedsUpdate... $ ghc --version The Glorious Glasgow Haskell Compilation System, version 8.0.2 But then I tried to install "stack" and it failed with: "error: failed to commit transaction (conflicting files) ghc-libs: /usr/bin/ghc-pkg exists in filesystem": $ sudo pacman -Syu stack :: Synchronizing package databases... core is up to date extra is up to date haskell-core is up to date community is up to date :: Starting full system upgrade... resolving dependencies... looking for conflicting packages... Packages (170) ghc-libs-8.2.1-1 haskell-aeson-1.0.2.1.x1-2 haskell-aeson-compat-0.3.6.x6-2 haskell-annotated-wl-pprint-0.7.0.x1-2 haskell-ansi-terminal-0.6.2.3.x0-252 haskell-ansi-wl-pprint-0.6.7.3.x0-252 haskell-asn1-encoding-0.9.5.x0-3 haskell-asn1-parse-0.9.4.x0-257 haskell-asn1-types-0.3.2.x0-256 haskell-async-2.1.1.1.x0-1 haskell-attoparsec-0.13.1.0.x0-7 haskell-attoparsec-iso8601-1.0.0.0.x0-1 haskell-auto-update-0.1.4.x0-252 haskell-base-compat-0.9.3.x0-1 haskell-base-orphans-0.6.x0-1 haskell-base16-bytestring-0.1.1.6.x0-252 haskell-base64-bytestring-1.0.0.1.x0-252 haskell-bifunctors-5.4.2.x0-1 haskell-bindings-uname-0.1-2 haskell-bitarray-0.0.1.1.x0-2 haskell-blaze-builder-0.4.0.2.x0-252 haskell-blaze-html-0.9.0.1.x0-1 haskell-blaze-markup-0.8.0.0.x0-1 haskell-byteable-0.1.1.x0-252 haskell-call-stack-0.1.0.x0-2 haskell-case-insensitive-1.2.0.9.x0-1 haskell-cereal-0.5.4.0.x0-2 haskell-clock-0.7.2.x0-2 haskell-comonad-5.0.1.x0-1 haskell-conduit-1.2.10.x0-1 haskell-conduit-extra-1.1.15.x1-2 haskell-connection-0.2.8.x0-3 haskell-contravariant-1.4.x0-255 haskell-cookie-0.4.2.1.x0-252 haskell-cryptohash-0.11.9.x0-259 haskell-cryptohash-sha256-0.11.100.1.x1-1 haskell-cryptonite-0.22.x0-3 haskell-cryptonite-conduit-0.2.0.x0-4 haskell-data-default-class-0.1.2.0.x0-252 haskell-digest-0.0.1.2.x0-252 haskell-distributive-0.5.2.x2-2 haskell-dlist-0.8.0.2.x0-2 haskell-easy-file-0.2.1.x0-252 haskell-echo-0.1.3-2 haskell-ed25519-0.0.5.0.x2-252 haskell-either-4.4.1.1.x1-8 haskell-exceptions-0.8.3.x1-3 haskell-extra-1.5.2.x0-1 haskell-fast-logger-2.4.10.x0-1 haskell-file-embed-0.0.10.x0-2 haskell-filelock-0.1.0.1.x0-252 haskell-foundation-0.0.9.x0-1 haskell-free-4.12.4.x0-257 haskell-fsnotify-0.2.1.x0-257 haskell-generic-deriving-1.11.2.x0-1 haskell-gitrev-1.2.0.x0-252 haskell-glob-0.7.14.x0-1 haskell-hackage-security-0.5.2.2.x3-1 haskell-hashable-1.2.6.0.x1-1 haskell-hastache-0.6.1.x5-1 haskell-hinotify-0.3.9.x0-4 haskell-hourglass-0.2.10.x0-252 haskell-hpack-0.17.0.x0-6 haskell-hspec-2.4.3.x0-1 haskell-hspec-core-2.4.3.x0-1 haskell-hspec-discover-2.4.3.x0-1 haskell-hspec-expectations-0.8.2.x0-3 haskell-hspec-smallcheck-0.4.2.x0-4 haskell-http-api-data-0.3.7.x0-1 haskell-http-client-0.5.6.1.x0-5 haskell-http-client-tls-0.3.4.1.x0-3 haskell-http-conduit-2.2.3.1.x0-8 haskell-http-types-0.9.1.x0-257 haskell-hunit-1.5.0.0.x0-2 haskell-ieee754-0.8.0.x0-1 haskell-integer-logarithms-1.0.1.x1-1 haskell-lifted-base-0.2.3.10.x0-4 haskell-logict-0.6.0.2.x0-2 haskell-memory-0.14.5.x0-1 haskell-microlens-0.4.8.0.x0-1 haskell-microlens-mtl-0.1.10.0.x0-1 haskell-microlens-th-0.4.1.1.x0-1 haskell-mime-types-0.1.0.7.x0-252 haskell-mintty-0.1.1-2 haskell-mmorph-1.0.9.x1-1 haskell-monad-control-1.0.1.0.x0-253 haskell-monad-logger-0.3.24.x0-1 haskell-monad-loops-0.4.3.x0-252 haskell-monadrandom-0.5.1.x0-1 haskell-mono-traversable-1.0.2.x0-3 haskell-mtl-2.2.1.x1-252 haskell-network-2.6.3.1.x0-252 haskell-network-uri-2.6.1.0.x0-252 haskell-old-locale-1.0.0.7.x1-252 haskell-old-time-1.1.0.3.x1-252 haskell-open-browser-0.2.1.0.x0-252 haskell-optparse-applicative-0.13.2.0.x0-1 haskell-optparse-simple-0.0.3.x0-262 haskell-parsec-3.1.11.x0-252 haskell-path-0.5.13.x0-1 haskell-path-io-1.2.2.x1-1 haskell-path-pieces-0.2.1.x1-252 haskell-pem-0.2.2.x0-252 haskell-persistent-2.6.1.x0-7 haskell-persistent-sqlite-2.6.2.x0-7 haskell-persistent-template-2.5.2.x0-7 haskell-pid1-0.1.0.1.x1-2 haskell-prelude-extras-0.4.0.3.x0-252 haskell-primitive-0.6.1.0.x1-252 haskell-profunctors-5.2.x1-2 haskell-project-template-0.2.0.x0-269 haskell-quickcheck-2.9.2.x0-4 haskell-quickcheck-io-0.1.4.x0-5 haskell-random-1.1.x1-1 haskell-regex-applicative-0.3.3.x0-252 haskell-regex-applicative-text-0.1.0.1.x0-252 haskell-resource-pool-0.2.3.2.x0-256 haskell-resourcet-1.1.9.x0-6 haskell-retry-0.7.4.2.x0-6 haskell-safe-0.3.14.x0-1 haskell-scientific-0.3.4.12.x0-1 haskell-semigroupoids-5.2.x0-1 haskell-semigroups-0.18.3.x0-1 haskell-setenv-0.1.1.3.x1-252 haskell-silently-1.2.5.x0-252 haskell-smallcheck-1.1.1.x1-3 haskell-socks-0.5.5.x1-253 haskell-split-0.2.3.1.x1-1 haskell-statevar-1.1.0.4.x0-253 haskell-stm-2.4.4.1.x1-1 haskell-stm-chans-3.0.0.4.x0-253 haskell-store-0.3.x2-4 haskell-store-core-0.3.x0-1 haskell-streaming-commons-0.1.17.x0-3 haskell-syb-0.6.x0-252 haskell-tagged-0.8.5.x1-2 haskell-tar-0.5.0.3.x0-252 haskell-temporary-1.2.0.4.x0-254 haskell-text-1.2.2.1.x0-252 haskell-text-metrics-0.2.0.x0-2 haskell-tf-random-0.5.x0-254 haskell-th-expand-syns-0.4.3.0.x0-1 haskell-th-lift-0.7.7.x0-1 haskell-th-lift-instances-0.1.11.x0-3 haskell-th-orphans-0.13.3.x0-9 haskell-th-reify-many-0.1.6.x0-8 haskell-th-utilities-0.2.0.1.x0-10 haskell-time-locale-compat-0.1.1.3.x0-252 haskell-tls-1.3.10.x2-2 haskell-transformers-base-0.4.4.x1-253 haskell-transformers-compat-0.5.1.4.x0-252 haskell-unicode-transforms-0.3.0.x0-1 haskell-unix-compat-0.4.3.1.x1-1 haskell-unix-time-0.3.7.x0-2 haskell-unliftio-0.1.0.0-5 haskell-unliftio-core-0.1.0.0-1 haskell-unordered-containers-0.2.8.0.x0-1 haskell-uri-bytestring-0.2.3.1.x0-3 haskell-uuid-types-1.0.3.x1-6 haskell-vector-0.12.0.1.x1-1 haskell-vector-algorithms-0.7.0.1.x1-2 haskell-void-0.7.2.x0-1 haskell-x509-1.6.5.x0-7 haskell-x509-store-1.6.2.x0-8 haskell-x509-system-1.6.4.x0-8 haskell-x509-validation-1.6.5.x0-8 haskell-yaml-0.8.22.x0-6 haskell-zip-archive-0.3.0.6.x0-1 haskell-zlib-0.6.1.2.x0-2 stack-1.5.1.20170916-2 Total Installed Size: 981.23 MiB :: Proceed with installation? [Y/n] (170/170) checking keys in keyring [#################################################################] 100% (170/170) checking package integrity [#################################################################] 100% (170/170) loading package files [#################################################################] 100% (170/170) checking for file conflicts [#################################################################] 100% error: failed to commit transaction (conflicting files) ghc-libs: /usr/bin/ghc-pkg exists in filesystem Errors occurred, no packages were upgraded. My guess is that the conflict is because "ghc-libs-8.2.1-1" is being installed which is version 8.2.1 where as ArchHaskell hasn't updated to 8.2.1 yet. What would you advise? -- Wink [1] https://wiki.archlinux.org/index.php/ArchHaskell#haskell-core