== foo ==
fun foo() {
    x = ""
}
---------------------
L0:
  1 <START>
  2 mark({ x = "" })
    mark("")
    r("") -> <v0>
    magic[UNSUPPORTED_ELEMENT](x = ""|<v0>) -> <v1>
L1:
  1 <END>                                              NEXT:[<SINK>]
error:
    <ERROR>                                            PREV:[]
sink:
    <SINK>                                             PREV:[<ERROR>, <END>]
=====================