public override void Initialize()

in Blog-FIPs/FipsCodeAnalyzer/FipsCodeAnalyzer/FipsCodeAnalyzerAnalyzer.cs [43:111]
47 lines of code
7 McCabe index (conditional complexity)

        public override void Initialize(AnalysisContext context)
        {
            // TODO: Consider registering other actions that act on syntax instead of or in addition to symbols
            // See https://github.com/dotnet/roslyn/blob/master/docs/analyzers/Analyzer%20Actions%20Semantics.md for more information
            context.RegisterSymbolAction(AnalyzeSymbol, SymbolKind.NamedType);
            context.RegisterCompilationStartAction((CompilationStartAnalysisContext context) =>
            {
                context.RegisterOperationAction(
                    (OperationAnalysisContext operationAnalysisContext) =>
                    {
                        IMethodSymbol method;

                        switch (operationAnalysisContext.Operation)
                        {
                            case IInvocationOperation invocationOperation:
                                method = invocationOperation.TargetMethod;
                                break;
                            case IObjectCreationOperation objectCreationOperation:
                                method = objectCreationOperation.Constructor;
                                break;
                            default:
                                Debug.Fail($"Unhandled IOperation {operationAnalysisContext.Operation.Kind}");
                                return;
                        }

                        INamedTypeSymbol type = method.ContainingType;
                        DiagnosticDescriptor rule = null;
                        string algorithmName = string.Empty;

                       // INamedTypeSymbol? DES;
                        //DES = context.Compilation.GetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemSecurityCryptographyDES);
                        string fullName = type.ToDisplayString();

                        if (fullName == null || !fullName.StartsWith("System.Security.Cryptography"))
                            return;

                        //-- this safe approach is less than ideal... 
                        //   it will result in several false positives, however,
                        //   as the .net core framework expands this is better than
                        //   trying to block the non-fips ones.
                        if (!fipsOkayCryptoList.Contains(type.Name))
                        {
                            rule = Rule;
                            algorithmName = type.Name;
                        }

                        if (rule == null)
                        {
                            return;
                        }

                        operationAnalysisContext.ReportDiagnostic(
                        Diagnostic.Create(
                            rule,
                            operationAnalysisContext.Operation.Syntax.GetLocation(),
                            operationAnalysisContext.ContainingSymbol.Name,
                            algorithmName));

                        //if (type.DerivesFrom())
                        //{
                        //    rule = DoNotUseBrokenCryptographyRule;
                        //    algorithmName = cryptTypes.DES.Name;
                        //}

                    },
                        OperationKind.Invocation,
                        OperationKind.ObjectCreation);
            });
        }