== foo ==
fun foo(x: Int) {
    val (a, b) = x
    a
}
---------------------
L0:
  1 <START>
    v(x: Int)
    magic(x: Int) -> <v0>
    w(x|<v0>)
  2 mark({ val (a, b) = x a })
    r(x) -> <v1>
    v(a)
    magic(a|<v1>) -> <v2>
    w(a|<v2>)
    v(b)
    magic(b|<v1>) -> <v3>
    w(b|<v3>)
    r(a) -> <v4>
L1:
  1 <END>                         NEXT:[<SINK>]
error:
    <ERROR>                       PREV:[]
sink:
    <SINK>                        PREV:[<ERROR>, <END>]
=====================