Resolving dependencies...
cabal: Could not resolve dependencies:
trying: intero-0.1.19 (user goal)
next goal: ghc (dependency of intero-0.1.19)
rejecting: ghc-8.0.1.20161018/installed-8.0... (conflict: intero => ghc>=7.8
&& <=8.0.1)
Dependency tree exhaustively searched.