virtpatmat

gistfile1.txt

m:.../quick/bin % cat vpm.scala
object vpm {
  Option(0) match {
  case Some(0) => 1
  case None => 2
  }
}

m:.../quick/bin % ./scalac -Xprint:typer vpm.scala
[[syntax trees at end of typer]]// Scala source: vpm.scala
package <empty> {
  final object vpm extends Object with ScalaObject {
    def <init>(): object vpm = {
      vpm.super.<init>();
      ()
    };
    scala.Option.apply[Int](0) match {
      case (x: Int)Some[Int](0) => 1
      case scala.None => 2
    }
  }
}

m:.../quick/bin % ./scalac -Xprint:typer -Yvirtpatmat vpm.scala
[[syntax trees at end of typer]]// Scala source: vpm.scala
package <empty> {
  final object vpm extends Object with ScalaObject {
    def <init>(): object vpm = {
      vpm.super.<init>();
      ()
    };
    scala.this.MatchingStrategy.OptionMatchingStrategy.runOrElse[Option[Int], Int](scala.Option.apply[Int](0))(((x1: Option[Int]) => scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Some[Int]](x1.isInstanceOf[Some[Int]], x1.asInstanceOf[Some[Int]]).flatMap[Int](((x3: Some[Int]) => if (x3.ne(null))
  scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Int](0.==(x3.x), x3.x).flatMap[Int](((x4: Int) => scala.this.MatchingStrategy.OptionMatchingStrategy.one[Int](1)))
else
  scala.this.MatchingStrategy.OptionMatchingStrategy.zero)).orElse[Int](scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Option[Int]](scala.None.==(x1), x1).flatMap[Int](((x5: Option[Int]) => scala.this.MatchingStrategy.OptionMatchingStrategy.one[Int](2))))))
  }
}

-----------------------

# orElse の型エラー直してない場合

m:.../quick/bin % ./scalac -Xprint:typer -Yvirtpatmat vpm.scala
vpm.scala:2: error: type arguments [Option[Int]] do not conform to method orElse's type parameter bounds [B >: Int]
  Option(0) match {
        ^
[[syntax trees at end of typer]]// Scala source: vpm.scala
package <empty> {
  final object vpm extends Object with ScalaObject {
    def <init>(): object vpm = {
      vpm.super.<init>();
      ()
    };
    scala.this.MatchingStrategy.OptionMatchingStrategy.runOrElse[Option[Int], Int](scala.Option.apply[Int](0))(((x1: Option[Int]) => scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Some[Int]](x1.isInstanceOf[Some[Int]], x1.asInstanceOf[Some[Int]]).flatMap(((x3: Some[Int]) => if (x3.ne(null))
  scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Int](0.==(x3.x), x3.x).flatMap(((x4: Int) => scala.this.MatchingStrategy.OptionMatchingStrategy.one(1.asInstanceOf[Int(1)])))
else
  scala.this.MatchingStrategy.OptionMatchingStrategy.zero)).orElse[Option[Int]](scala.this.MatchingStrategy.OptionMatchingStrategy.guard[Option[Int]](scala.None.==(x1), x1).flatMap(((x5: Option[Int]) => scala.this.MatchingStrategy.OptionMatchingStrategy.one(2.asInstanceOf[Int(2)]))))))
  }
}

one error found