| has_reffield(r0, st -- r), is_valid_ref(r0, st) ⊦ r0 = r, has_reffield(r0, st) |
⊦ is_valid_ref(r, st) ↔ is_obj(r, st) ∨ is_array(r, st)
has_reffield(r0, st -- r), is_obj(r0, st) ∨ is_array(r0, st) ⊦ r0 = r, has_reffield(r0, st)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, r0)]]