public IEnumerable <DocumentId> GetChangedAnalyzerConfigDocuments()
{
// if the document states are different then there is a change.
foreach (var doc in _newProject.AnalyzerConfigDocuments)
{
var newState = _newProject.GetAnalyzerConfigDocumentState(doc.Id);
var oldState = _oldProject.GetAnalyzerConfigDocumentState(doc.Id);
if (oldState != null && newState != oldState)
{
yield return(doc.Id);
}
}
}