A legacy is given to A, and, in case of his dying before the testator, to B. A dies before the…

Section 105(1) makes a legacy lapse on the legatee's death before the testator "unless it appears by the Will that the testator intended that it should go to some other person". The will here provides for exactly that event, and Illustration (iii) to section 105 says "the legacy goes to B". A's heirs take nothing, since A never became entitled.