C#中自定义显式/隐式转换的问题

Question

在C#中如果定义显式/隐式转换是不是没有位置的要求，只要在任一类中定义了转换就可以？

例如代码1和代码2木有区别咯？

代码1

    public class ConvClass1
    {
        public int val;

        public static implicit operator ConvClass2(ConvClass1 op1)
        {
            ConvClass2 returnVal = new ConvClass2();
            returnVal.val = op1.val;
            return returnVal;
        }

        public static implicit operator ConvClass1(ConvClass2 op1)
        {
            ConvClass1 returnVal = new ConvClass1();
            checked { returnVal.val = (int)op1.val; }
            return returnVal;
        }
    }

    public class ConvClass2
    {
        public double val;


    }

代码2

   public class ConvClass1
    {
        public int val;

        public static implicit operator ConvClass2(ConvClass1 op1)
        {
            ConvClass2 returnVal = new ConvClass2();
            returnVal.val = op1.val;
            return returnVal;
        }

       
    }

    public class ConvClass2
    {
        public double val;
        public static implicit operator ConvClass1(ConvClass2 op1)
        {
            ConvClass1 returnVal = new ConvClass1();
            checked { returnVal.val = (int)op1.val; }
            return returnVal;
        }

    }

Answer 1

应该没区别吧