Just install Ghci 8.6.x
Sat May 4 12:25:14 2019 brew install ghc, ghc 8.6x in /usr/local/Cellar/ghc/8.6.5/bin/ghc All my Haskell is using 8.4.x in /usr/local/bin
Here is my note about Haskell on my Mac OSX[EL Capitan]
Mac OS X El Capitan broke my Haskell GHCi [7.10.2]
Sat May 14 13:57:22 PDT 2016 Today I try to test De Casteliau's algorithm in Haskell and run GHCi, and start up GHCi on command line I got a strangle error from GHCi "can't open /tmp/ghci.log" file when I run a simple expression such as 1 + 2 in GHCi I never have the problem before I update my Mac OS to El capitan. Good Job Apple! I downloaded new version GHCi 7.10.3 and install it. Run the GHCi in command, the same error pops up again! Update: Apple change some permission for Clang something that causes the error Location for GHCi and HaskellFrame when Haskell is installed in Mac OSX[EL Capitan or Yosemite or Mavericks] /Library/Frameworks/GHC.framework /Library/Haskell Uninstaller Location[At least on my Mac OSX El Capitan] /usr/local/bin/uninstall-hs
How to clear up GHCi from your Mac OSX
If you run /usr/local/bin/uninstall-hs, it only clean up some stuff, but not all
                    sudo rm -rf /Library/Frameworks/GHC.framework
                    sudo rm -rf /Library/Frameworks/HaskellPlatform.framework
                    sudo rm -rf /Library/Haskell
                    rm -rf ~/.cabal
                    rm -rf ~/.ghc
                    rm -rf ~/Library/Haskell
                    rm -rf /Applications/ghc-7.10.3.app
                    rm -rf /Users/cat/.ghc
                    rm -rf /Users/cat/.ghc
                    rm -rf /opt/local/bin/ghci
                    rm -rf /opt/local/bin/ghci-*
                    rm -rf /opt/local/lib/ghc-*
Remove all Cabal, CHGi, GHC framework from my Mac OSX and reinstall Haskell 7.10.3
I spend many hours on the issue with Apple EL Capitan updategrade. I don't realize Apple push a shity OSX out, even though they know there are shitload of bugs
New version of directory module in Haskell
import Sytem.Directory listDirectory shows "Not in scope:" error message list all the packages ghc-pkg list shows the directory package is old [directory-] listDirectory is in [] run: cabal install cabal-install [update cabal] run: cabal install directory- it works after install the directory-