PatMat & exhastivity spec OrTypes

[DarkDimius]

How should this compile? Is the pattern exhaustive? Does it have unreachable cases?

object A {
  def foo(a: Int | Double) = a match {case a: (Float | Boolean) => 1}
  def fooUnsafe(a: Int | Double) = a.isInstanceOf[ Float | Boolean] // is it true or false?
}

[DarkDimius]

had a discussion, decided that:

1. the pattern is not exhastive and the single case is dead code
2. method should return false

[liufengyun]

If I were right, the key to solve this problem here is to translate x.isInstanceOf[T1 | T2] to x.isInstanceOf[T1] | x.insInstanceOf[T2] before type erasure?