While making a Bladesinger Wizard, I wondered if I would be able to use Booming Blade twice while hasted.
Booming Blade: As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails.
Haste: Until the spell ends, the target’s speed is doubled, it gains a +2 bonus to AC, it has advantage on Dexterity saving throws, and it gains an additional action on each of its turns. That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action.
What exactly does "one weapon attack only" mean? Is this to prevent characters with the Extra Attack feature from making 2 attacks? Does this prevent me from casting 2 spells (cantrips or higher-level spells) in a single turn?