Manual XOR between a destination and fetch options.
WithoutExclusive<T, U> nevers every key of T that is NOT also in U — so the discriminators
shared by both branches stay accessible, while exclusive keys are correctly forbidden
on the opposite branch.
Manual XOR between a destination and fetch options.
WithoutExclusive<T, U>nevers every key ofTthat is NOT also inU— so the discriminators shared by both branches stay accessible, while exclusive keys are correctly forbidden on the opposite branch.