What is the static analysis rule to warn about unused using statements?

问题

Is there any FxCop or StyleCop that warns when there is an using statement that is no longer referenced by any object in the file?

回答1:

You can enable the rule IDE0005 C# Using directive is unnecessary. in the category Style.

回答2:

In addition to Udo's answer and this answer, I also needed to uncheck Suppress results from generated code (managed only) which can be found under Properties > Code Analyses.

So all in all:

1. Set the Warning Level to 4 for code analyzers to fire.
2. Set rules CS8019 and IDE0005 to warning in your projects' Code Analysis rules (Properties > Code Analysis).
3. Make sure to uncheck Suppress results from generated code (managed only) which can be found under Properties > Code Analyses.

来源：https://stackoverflow.com/questions/39043332/what-is-the-static-analysis-rule-to-warn-about-unused-using-statements