Definition eq := slot_eq.Module OrderedSlot := OrderedIndexed(IndexedSlot).Definition t := loc.Definition eq (x y: t) := x = y.Definition lt (x y: t) :=
    match x, y with
    | R r1, R r2 => Plt (IndexedMreg.index r1) (IndexedMreg.index r2)
    | R _, S _ _ _ => True
    | S _ _ _, R _ => False
    | S sl1 ofs1 ty1, S sl2 ofs2 ty2 =>
        OrderedSlot.lt sl1 sl2 \/ (sl1 = sl2 /\
        (ofs1 < ofs2 \/ (ofs1 = ofs2 /\ OrderedTyp.lt ty1 ty2)))
    end.

Lemma lt_trans : forall x y z : t, lt x y -> lt y z -> lt x z.