Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: email (user goal)
rejecting: email-0.1.1.2 (constraint from user target requires ==0.1.1.1)
trying: email-0.1.1.1
next goal: ghc (dependency of email-0.1.1.1)
rejecting: ghc-8.0.1.20161018/installed-8.0... (conflict: email => ghc>=6.10
&& <7.2)
Dependency tree exhaustively searched.