| validrefnotnull(str, r, ty, st), st ⊆ st1 ⊦ r = jvmref, validref(str, r, ty, st1) |
⊦ validrefnotnull(str, r, ty, st) ↔ r ≠ jvmref ∧ validref(str, r, ty, st)
r ≠ jvmref ∧ validref(str, r, ty, st), st ⊆ st1 ⊦ r = jvmref, validref(str, r, ty, st1)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, ty, r, str)]]