Venerable Ānanda asked the Buddha, “Bhante, the monk named Asoka has passed away. Where has he been reborn? The nun named Asokā, the male lay-follower named Asoka, and the female lay-follower named Asokā have passed away. Where have they been reborn?”
“Ānanda, the monk, Asoka, had already attained enlightenment before passing away. Therefore, he didn’t take rebirth in any world.
All is explained as in SN 55.8.
“Ānanda, this is that mirror of the Dhamma. A noble disciple who has these qualities may declare of himself: ‘I will never be reborn in hell, the animal world, and the ghost world. I’ve finished with all miserable worlds. I am a stream-enterer! I’m not liable to be reborn in lower worlds, and I am heading towards Nibbāna.’”