Bismillah.
Shaykh of shias at-Toose narrated in his “al-Amali” (p 39) from Dakhak:
سمعت علي بن أبي طالب ( عليه السلام ) يقول : أتاني أبو بكر وعمر فقالا : لو أتيت رسول الله ( صلى الله عليه وآله ) فذكرت له فاطمة .قال : فأتيته ، فلما رآني رسول الله ( صلى الله عليه وآله وسلم ) ضحك ، ثم قال : ما جاء بك يا أبا الحسن وما حاجتك ؟ قال : فذكرت له قرابتي وقدمي في الاسلام ونصرتي له وجهادي ، فقال : يا علي ، صدقت ، فأنت أفضل مما تذكر . فقلت : يا رسول الله ، فاطمة تزوجنيها ؟ …”
Translation:
I heard Ali ibn Abu Talib (alaihi salam) said: Abu Bakr and Umar approached me and said: May be you would approach prophet (sallalahu alaihi wa ala alihi wa sallam) and mentioned him Fatima? (Ali) said: And I approached him, and when prophet (sallalahu alaihi wa ala alihi wa sallam) seen me, he laughed. Then he said: What brought you here, and what is your problem o abul Hasan? And I (Ali) mentioned him my kinship, and my first acceptance of Islam, my help to him, and my jihaad. He (prophet) said: You spoke the truth. And you are better than you said. I (Ali) said: O messenger of Allah, Fatima.. Would you marry her to me?
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Interesting! This was after they(Abubakr and Kumar) made attempt and the prophet ( s) rejected their proposal.
Interesting! This was after they(Abubakr and Umar) made attempt to marry her but the prophet rejected them.
Why the prophet call him Abu Al-Hassan, and Ali isn’t yet married with fatima ? So Hassan isn’t born and he can’t be called Abu Al-Hassan.