| unchanged(str, r, st, st1), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st1[r -- _type] .type, st1) ⊦ junkref(str, r, st) |
unchanged(str, refs .first, st, st1), junkrefs(str, refs, st1[refs .first -- _type] .type, st1) ⊦ refs = [], junkref(str, refs .first, st)
[[CONCRETESIMPRULES : ()]]