| st ⊆ st1, st[r -- _type] .type ≤ ty ⊦ r = jvmref, validref(str, r, ty, st1), junkref(str, r, st) |
⊦ validref(str, r, ty, st) ↔ r = jvmref ∨ st[r -- _type] .type ≤ ty ∧ ¬ junkref(str, r, st)
st ⊆ st1, st[r -- _type] .type ≤ ty ⊦ r = jvmref, r = jvmref ∨ st1[r -- _type] .type ≤ ty ∧ ¬ junkref(str, r, st1), junkref(str, r, st)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st1, ty, r, str)]]