Musannaf Ibn Abi Shayba 23:203

Ishaq ibn Sulayman narrated to us, from Abu Ja'far, from Ayyub, from Nafi', from Ibn 'Umar, that 'Uthman woke up speaking to the people. He said: "I saw the Messenger of Allah, may Allah bless him and grant him peace, tonight in a dream, and he said: 'O 'Uthman, break your fast with us.'" So he woke up and was killed on that same day.