Reports different ways of checking emptiness of collections and Options and suggests replacing them with .isEmpty, .nonEmpty, or .isDefined.

Example:


  !Seq(1).isEmpty
  Seq(1).size == 0
  Seq(1).size != 0
  !(Seq(1).length > 0)
  Seq(1).exists(_ => true)
  import scala.Function.const
  Seq(1).exists(const(true))
  !Option(0).isEmpty
  Option(0) == None
  Option(0) != None

After the quick-fix is applied:


  Seq(1).nonEmpty
  Seq(1).isEmpty
  Seq(1).nonEmpty
  Seq(1).isEmpty
  Seq(1).nonEmpty
  import scala.Function.const
  Seq(1).nonEmpty
  Option(0).isDefined
  Option(0).isEmpty
  Option(0).isDefined