@konafusiona 20th lvl fighter with haste and 2-W fighting can make 6 attacks per round, right? Then action surge for 1 or 4 more? Yes, and Action Surge does let a fighter use Extra Attack again.

— Jeremy Crawford (@JeremyECrawford) February 3, 2016

@JeremyECrawford What about the additional action from a Haste spell? If used to attack, does extra attack get added to it as well?

— Ambryn (@konafusion) February 5, 2016

The haste spell states that you can make only one weapon attack with the action it provides. #DnD https://t.co/tR7JKfpvYa

— Jeremy Crawford (@JeremyECrawford) February 17, 2016