C#: Only extract Public and Protected members from reference assemblies.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/CodeAnalysisExtensions/SymbolExtensions.cs

@@ -642,5 +642,11 @@ public static AnnotatedTypeSymbol GetType(this Context cx, Microsoft.CodeAnalysi
         /// </summary>
         public static IEnumerable<AnnotatedTypeSymbol> GetAnnotatedTypeArguments(this INamedTypeSymbol symbol) =>
             symbol.TypeArguments.Zip(symbol.TypeArgumentNullableAnnotations, (t, a) => new AnnotatedTypeSymbol(t, a));
+
+        /// <summary>
+        /// Returns true if the symbol is public or protected.
+        /// </summary>
+        public static bool IsPublicOrProtected(this ISymbol symbol) =>
+            symbol.DeclaredAccessibility == Accessibility.Public || symbol.DeclaredAccessibility == Accessibility.Protected;
     }
 }

csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs

@@ -225,11 +225,12 @@ private void ExtractParametersForDelegateLikeType(TextWriter trapFile, IMethodSy
         }
 
         /// <summary>
-        /// Called to extract all members and nested types.
+        /// Called to extract members and nested types.
         /// This is called on each member of a namespace,
         /// in either source code or an assembly.
+        /// <param name="onlyEffectivelyPublic">If true, only extract members that are effectively public otherwise extract all members.</param>
         /// </summary>
-        public void ExtractRecursive()
+        public void ExtractRecursive(bool onlyEffectivelyPublic = false)
         {
             foreach (var l in Symbol.DeclaringSyntaxReferences.Select(s => s.GetSyntax().GetLocation()))
             {
@@ -238,10 +239,13 @@ public void ExtractRecursive()
 
             foreach (var member in Symbol.GetMembers())
             {
+                if (onlyEffectivelyPublic && !member.IsPublicOrProtected())
+                    continue;
+
                 switch (member.Kind)
                 {
                     case SymbolKind.NamedType:
-                        Create(Context, (ITypeSymbol)member).ExtractRecursive();
+                        Create(Context, (ITypeSymbol)member).ExtractRecursive(onlyEffectivelyPublic);
                         break;
                     default:
                         Context.CreateEntity(member);

csharp/extractor/Semmle.Extraction.CSharp/Extractor/Analyser.cs

@@ -271,7 +271,10 @@ private static void AnalyseNamespace(Context cx, INamespaceSymbol ns)
 
             foreach (var memberType in ns.GetTypeMembers())
             {
-                Entities.Type.Create(cx, memberType).ExtractRecursive();
+                if (memberType.IsPublicOrProtected())
+                {
+                    Entities.Type.Create(cx, memberType).ExtractRecursive(onlyEffectivelyPublic: true);
+                }
             }
         }
 

csharp/extractor/Semmle.Extraction.CSharp/Extractor/Extractor.cs

@@ -549,7 +549,6 @@ private static ExitCode AnalyseTracing(
                         compilerArguments.CompilationOptions
                             .WithAssemblyIdentityComparer(DesktopAssemblyIdentityComparer.Default)
                             .WithStrongNameProvider(new DesktopStrongNameProvider(compilerArguments.KeyFileSearchPaths))
-                            .WithMetadataImportOptions(MetadataImportOptions.All)
                         );
                 },
                 (compilation, options) => analyser.EndInitialize(compilerArguments, options, compilation, cwd, args),