| validrefs(str, r ' + refs, ty, st), ∃ refs0, refs1. refs = refs0 + r0 ' + refs1 ∧ ¬ r0 ∈ refs0, validrefs(str, r ' + refs, st[r -- _type] .type, st) ⊦ ∃ refs0. refs0 ≠ [] ∧ refs0 .first = r ∧ refs0 .last = r0 ∧ validrefs(str, refs0, st[refs0 .first -- _type] .type, st) |
validrefs(str, r ' + refs1 + r0 ' + refs0, ty, st), validrefs(str, r ' + refs1 + r0 ' + refs0, st[r -- _type] .type, st) ⊦ r0 ∈ refs1, ∃ refs0. refs0 ≠ [] ∧ refs0 .first = r ∧ refs0 .last = r0 ∧ validrefs(str, refs0, st[refs0 .first -- _type] .type, st)
[[CONCRETESIMPRULES : ()]]