== invoke ==
fun invoke(f: () -> Unit) {
    (f)()
}
---------------------
L0:
    <START>
    v(f: () -> Unit)
    w(f)
    mark({ (f)() })
    mark((f)())
    mark((f))
    r(f)
    call((f), <for expression (f)>)
L1:
    <END>                              NEXT:[<SINK>]
error:
    <ERROR>                            PREV:[]
sink:
    <SINK>                             PREV:[<ERROR>, <END>]
=====================