Address PR feedback

Author: stephentoub

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/Runtime/SealInternalTypes.cs

@@ -36,24 +36,35 @@ public override void Initialize(AnalysisContext context)
 
         private static void OnCompilationStart(CompilationStartAnalysisContext context)
         {
+            INamedTypeSymbol? comImportAttributeType = context.Compilation.GetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemRuntimeInteropServicesComImportAttribute);
+
             var candidateTypes = PooledConcurrentSet<INamedTypeSymbol>.GetInstance(SymbolEqualityComparer.Default);
             var baseTypes = PooledConcurrentSet<INamedTypeSymbol>.GetInstance(SymbolEqualityComparer.Default);
 
             context.RegisterSymbolAction(context =>
             {
                 var type = (INamedTypeSymbol)context.Symbol;
 
-                if (type.TypeKind is TypeKind.Class && !type.IsAbstract && !type.IsStatic && !type.IsSealed && !type.IsExternallyVisible())
+                if (type.TypeKind is TypeKind.Class &&
+                    !type.IsAbstract &&
+                    !type.IsStatic &&
+                    !type.IsSealed &&
+                    !type.IsExternallyVisible() &&
+                    (comImportAttributeType is null || !type.HasAttribute(comImportAttributeType)))
+                {
                     candidateTypes.Add(type);
+                }
 
-                for (var baseType = type.BaseType; baseType is not null; baseType = baseType.BaseType)
+                for (INamedTypeSymbol? baseType = type.BaseType; baseType is not null; baseType = baseType.BaseType)
+                {
                     baseTypes.Add(baseType.OriginalDefinition);
+                }
 
             }, SymbolKind.NamedType);
 
             context.RegisterCompilationEndAction(context =>
             {
-                foreach (var type in candidateTypes)
+                foreach (INamedTypeSymbol type in candidateTypes)
                 {
                     if (!baseTypes.Contains(type.OriginalDefinition))
                     {

src/NetAnalyzers/UnitTests/Microsoft.NetCore.Analyzers/Runtime/SealInternalTypesTests.cs

@@ -202,6 +202,30 @@ End Class
         #endregion
 
         #region No Diagnostic
+        [Fact]
+        public Task PublicClassType_NoDiagnostic_CS()
+        {
+            string source = $"public class C {{ protected class P {{ }} }}";
+
+            return VerifyCS.VerifyCodeFixAsync(source, source);
+        }
+
+        [Fact]
+        public Task AlreadySealedType_NoDiagnostic_CS()
+        {
+            string source = $"internal sealed class C {{ }}";
+
+            return VerifyCS.VerifyCodeFixAsync(source, source);
+        }
+
+        [Fact]
+        public Task ComImportAttributedType_NoDiagnostic_CS()
+        {
+            string source = $"[System.Runtime.InteropServices.ComImport] [System.Runtime.InteropServices.Guid(\"E8D59775-E821-4D6C-B63D-BB0D969361DA\")] internal class C {{ }}";
+
+            return VerifyCS.VerifyCodeFixAsync(source, source);
+        }
+
         [Theory]
         [InlineData("interface I { }")]
         [InlineData("struct S { }")]
@@ -331,6 +355,37 @@ public Task PartialClass_ReportedAndFixedAtAllLocations_CS()
             return test.RunAsync();
         }
 
+        [Fact(Skip = "Changes are being applied to .g.cs file")]
+        public Task PartialClass_OneGenerated_ReportedAndFixedAtAllNonGeneratedLocations_CS()
+        {
+            var test = new VerifyCS.Test
+            {
+                TestState =
+                {
+                    Sources =
+                    {
+                        ("File1.cs", @"internal class Base { }"),
+                        ("File2.cs", @"internal partial class {|#0:Derived|} : Base { }"),
+                        ("File3.g.cs", @"internal partial class {|#1:Derived|} : Base { }")
+                    },
+                    ExpectedDiagnostics =
+                    {
+                        VerifyCS.Diagnostic(Rule).WithArguments("Derived").WithLocation(0).WithLocation(1)
+                    }
+                },
+                FixedState =
+                {
+                    Sources =
+                    {
+                        ("File1.cs", @"internal class Base { }"),
+                        ("File2.cs", @"internal sealed partial class {|#0:Derived|} : Base { }"),
+                        ("File3.g.cs", @"internal partial class {|#1:Derived|} : Base { }")
+                    }
+                }
+            };
+            return test.RunAsync();
+        }
+
         [Fact]
         public Task PartialClass_ReportedAndFixedAtAllLocations_VB()
         {

src/Utilities/Compiler/WellKnownTypeNames.cs

@@ -296,6 +296,7 @@ internal static class WellKnownTypeNames
         public const string SystemRuntimeExceptionServicesHandleProcessCorruptedStateExceptionsAttribute = "System.Runtime.ExceptionServices.HandleProcessCorruptedStateExceptionsAttribute";
         public const string SystemRuntimeInteropServicesCharSet = "System.Runtime.InteropServices.CharSet";
         public const string SystemRuntimeInteropServicesCoClassAttribute = "System.Runtime.InteropServices.CoClassAttribute";
+        public const string SystemRuntimeInteropServicesComImportAttribute = "System.Runtime.InteropServices.ComImportAttribute";
         public const string SystemRuntimeInteropServicesComSourceInterfacesAttribute = "System.Runtime.InteropServices.ComSourceInterfacesAttribute";
         public const string SystemRuntimeInteropServicesComVisibleAttribute = "System.Runtime.InteropServices.ComVisibleAttribute";
         public const string SystemRuntimeInteropServicesDefaultDllImportSearchPathsAttribute = "System.Runtime.InteropServices.DefaultDllImportSearchPathsAttribute";