global installation of:
cabal install happy
cabal install ghc-mod
apm install linter
apm install language-haskell
apm install linter-hlint
- Edit -> Preferences -> Packages
- Search for haskell-ghc-mod, click Settings
- Scroll down to Ghc-Mod Path -> copy and paste result of which ghc-mod
- Scroll down to Ghc-Modi Path -> copy and paste result of which ghc-modi
- Ensure Enable Ghc Modi is ticked (enabled)
- Now close ALL tabs/files *
- Restart atom and open Haskell file. It should work.