Use Option(x) instead of Some(x) to avoid Some(null)

NullNotNone.scala

object NullNotNone {
  def main(args: Array[String]) {
    test_func match {
      case None => println("null is not none")
      case Some(x) => println("so easy to be wrong")
    }
  }

  def test_func: Option[java.lang.Double] = Some(null)
}

// Option源代码(Source Code of Option)
object Option {
  import scala.language.implicitConversions

  /** An implicit conversion that converts an option to an iterable value
   */
  implicit def option2Iterable[A](xo: Option[A]): Iterable[A] = xo.toList

  /** An Option factory which creates Some(x) if the argument is not null,
   *  and None if it is null.
   *
   *  @param  x the value
   *  @return   Some(value) if value != null, None if value == null
   */
  def apply[A](x: A): Option[A] = if (x == null) None else Some(x)

  /** An Option factory which returns `None` in a manner consistent with
   *  the collections hierarchy.
   */
  def empty[A] : Option[A] = None
}