== Bar ==
abstract class Bar {
    abstract var bar : String
    fun foo() = "foo" + this.$bar
}
---------------------
L0:
    <START>
    v(abstract var bar : String)
L1:
    <END>                           NEXT:[<SINK>]
error:
    <ERROR>                         PREV:[]
sink:
    <SINK>                          PREV:[<ERROR>, <END>]
=====================
== foo ==
fun foo() = "foo" + this.$bar
---------------------
L0:
    <START>
    mark("foo" + this.$bar)
    mark("foo")
    r("foo")
    mark(this.$bar)
    r(this)
    r($bar)
    call(+, plus)
L1:
    <END>                      NEXT:[<SINK>]
error:
    <ERROR>                    PREV:[]
sink:
    <SINK>                     PREV:[<ERROR>, <END>]
=====================