The Wild Magic result on 27-28 is
For the next minute, all your spells with a casting time of 1 action have a casting time of 1 bonus action.
Does this mean that you can only cast spells (other than reaction spells) as a bonus action, and that you can't use your action to cast one normally?
I am specifically asking whether or not your spells with a casting time of 1 action can still be cast with an action, or whether the effect absolutely replaces the casting time rather than expanding your options.