Although unnecessary ``++using++`` won't change anything to the produced application, removing them:

* Will help readability and maintenance.
* Will help reduce the number of items in the IDE auto-completion list when coding.
* May avoid some name collisions.
* May improve compilation time because the compiler has fewer namespaces to look-up when it resolves types.
* The build will fail if this namespace is removed from the project.

== Noncompliant Code Example

----
using System.Collections.Generic; // Noncompliant - unnecessary using

namespace Foo
{
    public class Bar
    {
        public Bar(string path)
        {
            File.ReadAllLines(path);
        }
    }
}
----

== Compliant Solution

----
using System.IO;

namespace Foo
{
    public class Bar
    {
        public Bar(string path)
        {
            File.ReadAllLines(path);
        }
    }
}
----