unused value of type Props with @react macro

[steinybot]

Something like this:

@react
class MyComponent extends Component {

  override type Props = String
  override type State = String

  override def initialState: String = props

  override def render(): ReactElement = state
}

Will fail to compile with:

[error] /Users/jason/src/bug-reports/src/main/scala/Main.scala:8:2: unused value of type MyComponent.Props (add `: Unit` to discard silently)
[error] @react
[error]  ^
[error] one error found

When using:

scalacOptions ++= Seq(
  "-Wnonunit-statement",
  "-Xfatal-warnings"
)

My guess is that it is from this:

    _root_.slinky.core.annotations.react.bump({
      null.asInstanceOf[Props];
      null.asInstanceOf[State];
      null.asInstanceOf[Snapshot];
      ()
    });

What is this for? Can we get rid of it? Or at the very least add the : Unit ascription.

Reproduction: https://github.com/steinybot/bug-reports/tree/slinky/unused-value-props