| sk .fs = mkfs(class, ty, fieldvar), goodfieldandtype(r, sk, st), st ⊆ st0, type∃(str, ty), is_reftype(ty) → validrefval(str, st[r -- sk], ty, st) ⊦ ty = void_type, goodfieldandtype(r, sk, st0) ∧ (is_reftype(ty) → validrefval(str, st0[r -- sk], ty, st0)) |
⊦ goodfieldandtype(r, sk, st) ↔ is_fskey(sk) ∧ r -- sk ∈ st ∧ okval(st[r -- sk], sk .fs .type)
sk .fs = mkfs(class, ty, fieldvar), is_fskey(sk) ∧ r -- sk ∈ st ∧ okval(st[r -- sk], sk .fs .type), st ⊆ st0, type∃(str, ty), is_reftype(ty) → validrefval(str, st[r -- sk], ty, st) ⊦ ty = void_type, goodfieldandtype(r, sk, st0) ∧ (is_reftype(ty) → validrefval(str, st0[r -- sk], ty, st0))
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, sk, r)]]