Scala 3 compiler plugins: matching on Match or UnApply

Question
1

In Scala 3 how can I extract a Match (or UnApply ) from a ValDef tree in a compiler plugin? In Scala 2 we do

override def transform(tree: Tree) {
    tree match {
        ...
        case dd @ ValDef(mods, name, tpt, rhs @ Match(_, _)) => ...
    }
}

and that works fine for something like val (a, b) = (1, 2)