What is the benefit of removing redundant imports in vb.net or using in c# file

Question

I have been using re-sharper for quite long time and get used to solving a lot of problems by type Alt+Enter,today one of my colleague ask what are the really benefits. And I could not say a word apart from if you are not using it why imports it.

Can someone explain to me what are the real benefits if any?

Answer 1

It is faster -- if you have a reference the compiler has to load the symbol tables.

Answer 2

There are no runtime or compilation performance benefits, at all. It just makes for prettier code.

Answer 3

Beside the fact that it cleans up your code, you can also minimize 'name clashes'.
For instance, when you have 2 types with the same name in different namespaces, and you do not use any type from one namespace ... You then do not have to specify the namespace of the type when using it, it keeps your code cleaner.

Answer 4

It'll reduce the size of your source code (very slightly), but also improves code quality in my opinion. If you only include what you need, it makes the intent of the file that much clearer.

If you're including a library you don't need, and I'm reading your code, I might end up wasting time trying to figure out where you reference it or why it's used.

Answer 5

If you import more than you need you run into a few issues:

• When you try to use a class, it is ambiguous which class you mean and you have to specify further to disambiguate
• Autocomplete suggests many things that you're unlikely to use (it typically does this anyway, but having extra usings just makes the problem worse).
• It's hard to tell which dependencies your class has just from looking at the using list.

Answer 6

It removes redundancy, which is a good thing. And its easy to get most of the needed using directives back, by pressing ALT+ENTER (with R#) or invoking the smart-tag by pressing CTRL+. (without R#) on the class that needs it.

On the negative side, you might lose sight of available extension methods, especially when the System.Linq namespace import is removed.