rspec/rules/S4047/csharp/rule.adoc

== Why is this an issue?

When a reference parameter (keyword ``++ref++``) is used, the passed argument type must exactly match the reference parameter type. This means that to be able to pass a derived type, it must be cast and assigned to a variable of the proper type. Use of generic methods eliminates that cumbersome down casting and should therefore be preferred.


This rule raises an issue when a method contains a ``++ref++`` parameter of type ``++System.Object++``.


=== Noncompliant code example

[source,csharp]
----
using System;

namespace MyLibrary
{
  public class Foo
  {
    public void Bar(ref object o1, ref object o2) // Noncompliant
    {
    }
  }
}
----


=== Compliant solution

[source,csharp]
----
using System;

namespace MyLibrary
{
  public class Foo
  {
    public void Bar<T>(ref T ref1, ref T ref2)
    {
    }
  }
}
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Make this method generic and replace the "object" parameter with a type parameter.


=== Highlighting

Primary: Method definition

Secondary: noncompliant parameter


endif::env-github,rspecator-view[]