(** A variant of [transl_expr_charact], for use when the destination register is the one associated with a variable. *)

Lemma transl_expr_assign_charact:
forall id a map rd nd s ns s' INCR
(TR: transl_expr map a rd nd s = OK ns s' INCR)
(WF: map_valid map s)
(OK: reg_map_ok map rd (Some id)),
tr_expr s'.(st_code) map nil a ns nd rd (Some id).