private or internal types or private members that are never executed or referenced are dead code: unnecessary, inoperative code that should be removed. Cleaning out dead code decreases the size of the maintained codebase, making it easier to understand the program and preventing bugs from being introduced.

Noncompliant Code Example

public class Foo
{
    private void UnusedPrivateMethod() {...} // Noncompliant

    private class UnusedClass {...} // Noncompliant
}

Compliant Solution

public class Foo
{
    public Foo()
    {
        UsedPrivateMethod();
    }

    private void UsedPrivateMethod()
    {
        var c = new UsedClass();
    }

    private class UsedClass {...}
}

Exceptions

This rule doesn’t raise issues on:

• Empty constructors
• Attributed members
• Main method
• Methods with event handler signature void Foo(object, EventArgs) that are declared in partial class
• Empty serialization constructor on type with System.SerializableAttribute attribute.
• Internals in assemblies that have a System.Runtime.CompilerServices.InternalsVisibleToAttribute attribute.