Finds public types in an assembly that are not exposed from a set of facades

PublicScanner.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection.Metadata;
using System.Reflection.PortableExecutable;


namespace PublicScanner
{
    class Program
    {
        static void Main(string[] args)
        {
            MetadataStringDecoder decoder = new MetadataStringDecoder(System.Text.Encoding.UTF8);

            PEReader reader = new PEReader(File.Open(@"C:\git\rt\bin\Windows_NT.x64.Debug\sdk\System.Private.CoreLib.dll", FileMode.Open));
            MetadataReader rdr = reader.GetMetadataReader(MetadataReaderOptions.Default, decoder);

            List<PEReader> facades = new List<PEReader>();
            List<MetadataReader> facadeReaders = new List<MetadataReader>();
            foreach (var fileName in Directory.EnumerateFiles(@"C:\git\rt\bin\Windows_NT.x64.Debug\framework\", "*.dll"))
            {
                var peReader = new PEReader(File.OpenRead(fileName));
                facades.Add(peReader);
                facadeReaders.Add(peReader.GetMetadataReader(MetadataReaderOptions.Default, decoder));
            }


            foreach (var definitionHandle in rdr.TypeDefinitions)
            {
                TypeDefinition typeDef = rdr.GetTypeDefinition(definitionHandle);

                const System.Reflection.TypeAttributes NestedMask = (System.Reflection.TypeAttributes)0x00000006;

                // TODO: handling of nested types
                if ((typeDef.Attributes & NestedMask) != 0)
                    continue;
                
                if ((typeDef.Attributes & System.Reflection.TypeAttributes.Public) == 0)
                    continue;

                string name = rdr.GetString(typeDef.Name);
                string ns = rdr.GetString(typeDef.Namespace);

                bool foundExport = false;
                foreach (var frdr in facadeReaders)
                {
                    foreach (var exportHandle in frdr.ExportedTypes)
                    {
                        ExportedType export = frdr.GetExportedType(exportHandle);
                        if (frdr.StringComparer.Equals(export.Name, name) && frdr.StringComparer.Equals(export.Namespace, ns))
                        {
                            foundExport = true;
                        }
                    }
                }

                if (!foundExport)
                    Console.WriteLine(rdr.GetString(typeDef.Name));
            }
        }
    }
}