== foo ==
fun foo(a: Any) {
    a as String
    a as? String
}
---------------------
L0:
  1 <START>
    v(a: Any)
    magic[FAKE_INITIALIZER](a: Any) -> <v0>
    w(a|<v0>)
  2 mark({ a as String a as? String })
    mark(a as String)
    r(a) -> <v1>
    magic[CAST](a as String|<v1>) -> <v2>
    mark(a as? String)
    r(a) -> <v3>
    magic[CAST](a as? String|<v3>) -> <v4>
L1:
  1 <END>                                      NEXT:[<SINK>]
error:
    <ERROR>                                    PREV:[]
sink:
    <SINK>                                     PREV:[<ERROR>, <END>]
=====================