Useful scalac options.

scalacOptions

scalacOptions ++= Seq(
  "-deprecation",           
  "-encoding", "UTF-8",       // yes, this is 2 args
  "-feature",                
  "-language:existentials",
  "-language:higherKinds",
  "-language:implicitConversions",
  "-unchecked",
  "-Xfatal-warnings",       
  "-Xlint",
  "-Yno-adapted-args",       
  "-Ywarn-dead-code",        // N.B. doesn't work well with the ??? hole
  "-Ywarn-numeric-widen",   
  "-Ywarn-value-discard",
  "-Xfuture",
  "-Ywarn-unused-import"     // 2.11 only
  "-Yno-predef"   // no automatic import of Predef (removes irritating implicits)
)