Sunan an-Nasa'i 33

أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ أَنْبَأَنَا أَزْهَرُ، أَنْبَأَنَا ابْنُ عَوْنٍ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ يَقُولُونَ إِنَّ النَّبِيَّ صلى الله عليه وسلم أَوْصَى إِلَى عَلِيٍّ لَقَدْ دَعَا بِالطَّسْتِ لِيَبُولَ فِيهَا فَانْخَنَثَتْ نَفْسُهُ وَمَا أَشْعُرُ فَإِلَى مَنْ أَوْصَى قَالَ الشَّيْخُ أَزْهَرُ هُوَ ابْنُ سَعْدٍ السَّمَّانُ ‏.‏

It was narrated that 'Aishah said:"They say that the Prophet (ﷺ) made a will for 'Ali,[1] but he called for a basin in which to urinate, then he went flaccid suddenly (and died), so how could he leave a will?!" The Shaikh said: Azhar (one of the narrators) is Ibn Sa'd As-Samman. [1] Meaning, appointing him as the Khalifah

Reference

Sunan an-Nasa'i 33

In-book

Book 1, Hadith 33