using System;

public class Program

{

    public static void Main()

    {

        Class c = new Class{ Property = 1};

    }

}

​

class Class

{

    int field;

    int propertyBackingField;

    public int Property

    {

        set // and no get-access

        {

            bool valueIsNegative = isNegative(value); // Method call. Client does not expect.

            if(valueIsNegative)

                throw new ArgumentException(); // Throwing an exception. Client does not expect. 

            field = -value; // Changes another field. Client does not expect.

            propertyBackingField = value;

        }

    }

    private bool isNegative(int value)

    {

        return value < 0;

    }

}