more-switches.scala

// source code
def test3(x: Int, y: Int): Int = (x: @switch) match {
  case 6 if y > 5 => 1
  //case 6 => 2
  case 12 => 3
  case 14 => 4
  case _ => 5
}

// dotty emits this if `case 6 =>` is present
def test3(x: Int, y: Int): Int = (x: @switch) match {
  case 6 =>
    if (y > 5) 1
    else 2
  case 12 => 3
  case 14 => 4
  case _ => 5
}

// scalac emits this
def test3(x: Int, y: Int): Int = (x: @switch) match {
  case 6 =>
    if (y > 5) 1
    else default()
  case 12 => 3
  case 14 => 4
  case _ =>
    default() {
      5
    }
}

// what dotty could emit to match scalac's capabilities
def test3(x: Int, y: Int): Int = {
  matchResult[Int]: {
    (x: @switch) match {
      case 6 =>
        if (y > 5) return[matchResult] 1
        else ()
      case 12 => return[matchResult] 3
      case 14 => return[matchResult] 4
      case _ => ()
    }
    5
  }
}

// what the tree-rendered of the Plan looks like
// which is what we should analyze to produce the previous snippet
def test3(x: Int, y: Int): Int = {
  val x1 = x
  matchResult[Int]: {
    if (x1 == 6) {
      if (y > 5) {
        return[matchResult] 1
      }
    }
    if (x1 == 12) {
      ...
    }
    return[matchResult] 5
  }
}