office-communicator

here you can watch how to set up StyleCop rules:

https://johnkoerner.com/csharp/using-analyzers-in-your-projects/

how stylecop throws errors instead of warns can be tested by adding some empty comments
some info about this - http://blogs.msdn.com/b/sourceanalysis/archive/2008/05/24/source-analysis-msbuild-integration.aspx