Sahih Bukhari · Hadith 2741

حدثنا عمرو بن زرارة، أخبرنا إسماعيل، عن ابن عون، عن إبراهيم، عن الأسود، قال ذكروا عند عائشة أن عليا رضى الله عنهما كان وصيا‏.‏ فقالت متى أوصى إليه وقد كنت مسندته إلى صدري أو قالت حجري فدعا بالطست، فلقد انخنث في حجري، فما شعرت أنه قد مات، فمتى أوصى إليه

Narrated Al-Aswad: In the presence of `Aisha some people mentioned that the Prophet had appointed `Ali by will as his successor. `Aisha said, "When did he appoint him by will? Verily when he died he was resting against my chest (or said: in my lap) and he asked for a wash-basin and then collapsed while in that state, and I could not even perceive that he had died, so when did he appoint him by will?"

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).