return (isException ? exceptionInstanceList : instanceList)[result];
IsNullValue resultValue = instanceList[result]; if (isException) resultValue = resultValue.toExceptionValue(); return resultValue;
	public static IsNullValue merge(IsNullValue a, IsNullValue b) {		boolean isException = a.isException() || b.isException();		a = a.toBaseValue();		b = b.toBaseValue();		// Left hand value should be >=, since it is used		// as the first dimension of the matrix to index.		if (a.kind < b.kind) {			IsNullValue tmp = a;			a = b;			b = tmp;		}		int result = mergeMatrix[a.kind][b.kind];		return (isException ? exceptionInstanceList : instanceList)[result];	}