foo1.cs

      public override AbstractValueWithInfo Divide(AbstractValue divisor)
      {
        switch (divisor)
        {
          case Scalar otherScalar when (otherScalar.Value == 0):
            return AbstractValueWithInfo.DivisionByZero;
          case Scalar otherScalar when (otherScalar.Value == 1):
            return new AbstractValueWithInfo(this, ErrorType.DivisionByOne);
          case Scalar otherScalar:
            var result = Divide(myInterval, otherScalar.Value);
            return new AbstractValueWithInfo(new Interval(result));

foo2.cs

      public override AbstractValueWithInfo Divide(AbstractValue divisor)
      {
        switch (divisor)
        {
          case Scalar(0):
            return AbstractValueWithInfo.DivisionByZero;
          case Scalar(1):
            return new AbstractValueWithInfo(this, ErrorType.DivisionByOne);
          case Scalar(var scalar):
            var result = Divide(myInterval, scalar);
            return new AbstractValueWithInfo(new Interval(result));