== unreachable ==
fun unreachable() {}
---------------------
L0:
  1 <START>
  2 mark({})
    read (Unit)
L1:
  1 <END>          NEXT:[<SINK>]
error:
    <ERROR>        PREV:[]
sink:
    <SINK>         PREV:[<ERROR>, <END>]
=====================
== a ==
fun a() {
    do {
    } while (true)
    unreachable()
}
---------------------
L0:
  1 <START>
  2 mark({ do { } while (true) unreachable() })
  3 mark(do { } while (true))
L2 [loop entry point]:
L4 [body entry point]:
    mark({ })                                      PREV:[mark(do { } while (true)), jmp(L2)]
    read (Unit)
L5 [body exit point]:
L6 [condition entry point]:
    r(true) -> <v0>
  2 magic[VALUE_CONSUMER](true|<v0>) -> <v1>
    jmp(L2)                                        NEXT:[mark({ })]
L3 [loop exit point]:
-   read (Unit)                                    PREV:[]
-   mark(unreachable())                            PREV:[]
-   call(unreachable(), unreachable) -> <v2>       PREV:[]
L1:
  1 <END>                                          NEXT:[<SINK>]                                         PREV:[]
error:
    <ERROR>                                        PREV:[]
sink:
    <SINK>                                         PREV:[<ERROR>, <END>]
=====================
== b ==
fun b() {
    while (true) {
    }
    unreachable()
}
---------------------
L0:
  1 <START>
  2 mark({ while (true) { } unreachable() })
L2 [loop entry point]:
L6 [condition entry point]:
    r(true) -> <v0>                             PREV:[mark({ while (true) { } unreachable() }), jmp(L2)]
    mark(while (true) { })
    magic[VALUE_CONSUMER](true|<v0>) -> <v1>
L4 [body entry point]:
  3 mark({ })
    read (Unit)
  2 jmp(L2)                                     NEXT:[r(true) -> <v0>]
L3 [loop exit point]:
L5 [body exit point]:
-   read (Unit)                                 PREV:[]
-   mark(unreachable())                         PREV:[]
-   call(unreachable(), unreachable) -> <v2>    PREV:[]
L1:
  1 <END>                                       NEXT:[<SINK>]                                      PREV:[]
error:
    <ERROR>                                     PREV:[]
sink:
    <SINK>                                      PREV:[<ERROR>, <END>]
=====================