Resolving dependencies...
cabal: Could not resolve dependencies:
trying: ghci-ng-10.0.0 (user goal)
next goal: ghc (dependency of ghci-ng-10.0.0)
rejecting: ghc-8.0.1.20161018/installed-8.0... (conflict: ghci-ng => ghc>=7.8
&& <8)
Dependency tree exhaustively searched.