private void CompareInterfaces() { IEnumerable <string> referenceInterfaces = ReferenceType.GetInterfaces().Select(@interface => @interface.GetCompareableName()).ToList(); IEnumerable <string> newInterfaces = NewType.GetInterfaces().Select(@interface => @interface.GetCompareableName()).ToList(); // missing interfaces foreach (string @interface in referenceInterfaces.Except(newInterfaces)) { ComparerResult.AddRemovedItem(ResultContext.Interface, @interface, Severity.Error); } // new interfaces foreach (string @interface in newInterfaces.Except(referenceInterfaces)) { ComparerResult.AddAddedItem(ResultContext.Interface, @interface, Severity.Warning); } }