If any person shall attest the execution of any will or codicil to whom any beneficial devise, legacy, estate, interest, gift, or appointment, or affecting any real or personal estate, other than and except charges and direction for the payment of any debt or debts, shall be thereby given or made, the devise, legacy, estate, interest, gift or appointment shall, so far only as concerns that person attesting the execution of the will, or codicil, or any person claiming under that person, be utterly null and void; but the person so attesting shall be admitted as a witness to prove the execution of the will, or codicil, or to prove the validity or invalidity thereof, notwithstanding the devise, legacy, estate, interest, gift, or appointment, mentioned in the will, or codicil.
R.I. Gen. Laws § 33-6-1