== foo ==
fun foo(): Int {
    val t = x@ (1 + 2)
    return t
}
---------------------
L0:
  1 <START>
  2 mark({ val t = x@ (1 + 2) return t })
    v(val t = x@ (1 + 2))
    mark(x@ (1 + 2))
    mark((1 + 2))
    r(1) -> <v0>
    r(2) -> <v1>
    mark(1 + 2)
    call(1 + 2, plus|<v0>, <v1>) -> <v2>
    w(t|<v2>)
    r(t) -> <v3>
    ret(*|<v3>) L1
L1:
  1 <END>                                    NEXT:[<SINK>]
error:
    <ERROR>                                  PREV:[]
sink:
    <SINK>                                   PREV:[<ERROR>, <END>]
=====================