== Why is this an issue?

Shadowing parent class members by creating properties and methods with the same signatures as non-``++virtual++`` parent class members can result in seemingly strange behavior if an instance of the child class is cast to the parent class. In such cases, the parent class' code will be executed instead of the code in the child class, confusing callers and potentially causing hard-to-find bugs.


Instead the child class member should be renamed.


=== Noncompliant code example

[source,csharp]
----
public class Fruit 
{
  public double GetCost() 
  {
    return 3.5;
  } 
}

public class Raspberry : Fruit 
{
  public new double GetCost()  // Noncompliant
  { 
    return 7.5;
  }
}

// ...
var r = new Raspberry();
var f = (Fruit) r;
Console.WriteLine(r.GetCost());  // prints 7.5
Console.WriteLine(f.GetCost());  // prints 3.5; there's only one instance but different code executes depending on cast
----


=== Compliant solution

[source,csharp]
----
public class Fruit 
{
  public double GetCost() 
  {
    return 3.5;
  } 
}

public class Raspberry : Fruit 
{
  public double GetInflatedCost() 
  { 
    return 7.5;
  }
}

// ...
var r = new Raspberry();
var f = (Fruit) r;
Console.WriteLine(r.GetCost());  // prints 3.5
Console.WriteLine(f.GetCost());  // prints 3.5; same code executes every time
Console.WriteLine(r.GetInflatedCost()); // prints 7.5
----


=== Exceptions

This rule ignores ``++private++`` parent class members, and any method named ``++Equals++``.


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