| sks0 ⊑ sks .butlast, fits(r, sks, st) ⊦ sks = [], is_referencevalue(st[r -- sks0]), junkref(str, r, st) |
sks = sks1 + sk ', sks0 ⊑ sks1, fits(r, sks, st) ⊦ sks = [], is_referencevalue(st[r -- sks0]), junkref(str, r, st)
[[CONCRETESIMPRULES : ([CSIMPELIM : sks ≠ [] ⊦ sk = sks .last ∧ sks0 = sks .butlast ↔ sks = sks0 + sk '])], [EXTRATERMS : (sks, sk, sks1)]]