Scala2.11 awesome!

build.sbt

scalaVersion := "2.11.0"

scalacOptions ++= Seq("-Ywarn-unused", "-Ywarn-unused-import", "-Xlint")

Main.scala

import scala.sys._

object Main{
  val a = b + "foo"
  val b = "b"

  private val c = 0
  private var d = 1

  println(d)

  def hoge(): Unit = {
    val x = 0
    println("foo $x")
  }
}

output

[warn] Main.scala:14: `$x` looks like an interpolated identifier! Did you forget the interpolator?
[warn]     println("foo $x")
[warn]             ^
[warn] Main.scala:1: Unused import
[warn] import scala.sys._
[warn]                  ^
[warn] Main.scala:7: private val in object Main is never used
[warn]   private val c = 0
[warn]               ^
[warn] Main.scala:8: private setter in object Main is never used
[warn]   private var d = 1
[warn]               ^
[warn] Main.scala:13: local val in method hoge is never used
[warn]     val x = 0
[warn]         ^
[warn] Main.scala:4: Reference to uninitialized value b
[warn]   val a = b + "foo"
[warn]           ^
[warn] 6 warnings found