| is_valid_ref(str, r, st) ⊦ r = jvmref, validrefs(str, r ', mkclasstype(`java.lang.Object' .class), st) |
⊦ validrefs(str, r ', ty, st) ↔ r = jvmref ∨ r ≠ jvmref ∧ is_valid_ref(str, r, st) ∧ st[r -- _type] .type ≤ ty
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ is_valid_ref(str, r, st) ∧ r ≠ jvmref → st[r -- _type] .type ≤ mkclasstype (`java.lang.Object' .class)])], [EXTRATERMS : (st, mkclasstype(`java.lang.Object' .class), r, str)]]