Definition dest_below (dst: destination) (g: generator) : Prop :=
match dst with
| For_set sd => Plt (sd_temp sd) g.(gen_next)
| _ => True
end.
Remark dest_for_val_below: forall g, dest_below For_val g.

Lemma dest_for_set_condition_set:
forall sd tmp tycast ty g1 g2, dest_below (For_set sd) g2 -> within tmp g1 g2 -> dest_below (For_set (SDcons tycast ty tmp sd)) g2.