-- in.cue --
root: {
    a: {
        $id: "valToOut"
        val: "foo"
        out: string
    }
    b: {
        $id: "valToOut"
        $after: a
        val: "bar"
        out: string
    }
    c: {
        $id: "valToOut"
        out: a.out + b.out
    }
}
-- out/run/errors --
-- out/run/t0 --
graph TD
  t0("root.a [Ready]")
  t1("root.b [Waiting]")
  t1-->t0
  t2("root.c [Waiting]")
  t2-->t0
  t2-->t1

-- out/run/t1 --
graph TD
  t0("root.a [Terminated]")
  t1("root.b [Ready]")
  t1-->t0
  t2("root.c [Waiting]")
  t2-->t0
  t2-->t1

-- out/run/t1/value --
{
	$id: "valToOut"
	val: "foo"
	out: "foo"
}
-- out/run/t2 --
graph TD
  t0("root.a [Terminated]")
  t1("root.b [Terminated]")
  t1-->t0
  t2("root.c [Ready]")
  t2-->t0
  t2-->t1

-- out/run/t2/value --
{
	$id: "valToOut"
	$after: {
		$id: "valToOut"
		val: "foo"
		out: "foo"
	}
	val: "bar"
	out: "bar"
}
-- out/run/t3 --
graph TD
  t0("root.a [Terminated]")
  t1("root.b [Terminated]")
  t1-->t0
  t2("root.c [Terminated]")
  t2-->t0
  t2-->t1

-- out/run/t3/value --
{
	$id: "valToOut"
	out: "foobar"
}