The marriage of a person shall act as a revocation of a will made by him or her previous to the marriage, unless it appears from the will that it was made in contemplation thereof; but if the will exercises a power of appointment and the real and personal property thereby appointed would not, in default of the appointment, pass to the persons who would have been entitled to it had it been the property and estate of the testator or testatrix making the appointment and had he or she died intestate, so much of the will as makes the appointment shall not be revoked by the marriage.