A sample application to retrieve all diagnostics related to the nullability

FetchAllNullableRules.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Reflection;
using System.Threading;
using Microsoft.CodeAnalysis.Diagnostics;
namespace TestNonNullableReferences
{
    class Program
    {
        static void Main(string[] args)
        {
            Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
            Thread.CurrentThread.CurrentUICulture = new CultureInfo("en-US");

            var assemblyWithAnalyzers = GetAssembliesWithAnalyzers();
            var output = new List<string>();
            output.Add("|Code|Title|");
            output.Add("|---|----|");
            foreach (var (id, title) in GetAllRules(assemblyWithAnalyzers))
            {
                if (title.Contains("null", StringComparison.InvariantCultureIgnoreCase))
                {
                    output.Add($"|{id}|{title}|");
                }
            }

            File.WriteAllLines(@"rules.md", output);
        }

        private static IEnumerable<Assembly> GetAssembliesWithAnalyzers()
        {
            yield return typeof(Microsoft.CodeAnalysis.CSharp.CSharpCompilation).Assembly;
        }

        private static IEnumerable<(string? id, string title)> GetAllRules(IEnumerable<Assembly> assembliesWithAnalyzers)
        {
            foreach (var assemblyWithAnalyzers in assembliesWithAnalyzers)
            {
                var types = assemblyWithAnalyzers.GetTypes();
                var baseType = typeof(DiagnosticAnalyzer);
                foreach (var type in types)
                {
                    if (baseType.IsAssignableFrom(type))
                    {
                        var instance = Activator.CreateInstance(type) as DiagnosticAnalyzer;
                        foreach (var diagnostic in instance.SupportedDiagnostics)
                        {
                            var title = diagnostic.Title?.ToString();
                            if (title!=null && string.IsNullOrWhiteSpace(title) == false)
                            {
                                yield return (diagnostic.Id, title);
                            }
                        }
                    }
                }
            }
        }
    }
}