Do not use an array for a pointer field that doesn't actually refer to an array

src/Microsoft.Windows.CsWin32/Generator.Com.cs

@@ -93,11 +93,12 @@ private TypeDeclarationSyntax DeclareInterfaceAsStruct(TypeDefinitionHandle type
     {
         TypeDefinition typeDef = this.Reader.GetTypeDefinition(typeDefHandle);
         string originalIfaceName = this.Reader.GetString(typeDef.Name);
-        IdentifierNameSyntax ifaceName = IdentifierName(this.GetMangledIdentifier(originalIfaceName, context.AllowMarshaling, isManagedType: true));
+        bool isManagedType = this.IsManagedType(typeDefHandle);
+        IdentifierNameSyntax ifaceName = IdentifierName(this.GetMangledIdentifier(originalIfaceName, context.AllowMarshaling, isManagedType));
         IdentifierNameSyntax vtblFieldName = IdentifierName("lpVtbl");
         var members = new List<MemberDeclarationSyntax>();
         var vtblMembers = new List<MemberDeclarationSyntax>();
-        TypeSyntaxSettings typeSettings = this.comSignatureTypeSettings;
+        TypeSyntaxSettings typeSettings = context.Filter(this.comSignatureTypeSettings);
         IdentifierNameSyntax pThisLocal = IdentifierName("pThis");
         ParameterSyntax? ccwThisParameter = this.canUseUnmanagedCallersOnlyAttribute && !this.options.AllowMarshaling && originalIfaceName != "IUnknown" && originalIfaceName != "IDispatch" && !this.IsNonCOMInterface(typeDef) ? Parameter(pThisLocal.Identifier).WithType(PointerType(ifaceName).WithTrailingTrivia(Space)) : null;
         List<QualifiedMethodDefinitionHandle> ccwMethodsToSkip = new();
@@ -132,8 +133,9 @@ private TypeDeclarationSyntax DeclareInterfaceAsStruct(TypeDefinitionHandle type
         ISet<string> declaredProperties = this.GetDeclarableProperties(
             allMethods.Select(qh => qh.Reader.GetMethodDefinition(qh.MethodHandle)),
             originalIfaceName,
-            allowNonConsecutiveAccessors: true);
-        ISet<string>? ifaceDeclaredProperties = ccwThisParameter is not null ? this.GetDeclarableProperties(allMethods.Select(qh => qh.Reader.GetMethodDefinition(qh.MethodHandle)), originalIfaceName, allowNonConsecutiveAccessors: false) : null;
+            allowNonConsecutiveAccessors: true,
+            context);
+        ISet<string>? ifaceDeclaredProperties = ccwThisParameter is not null ? this.GetDeclarableProperties(allMethods.Select(qh => qh.Reader.GetMethodDefinition(qh.MethodHandle)), originalIfaceName, allowNonConsecutiveAccessors: false, context) : null;
 
         foreach (QualifiedMethodDefinitionHandle methodDefHandle in allMethods)
         {
@@ -183,7 +185,7 @@ private TypeDeclarationSyntax DeclareInterfaceAsStruct(TypeDefinitionHandle type
 
             // We can declare this method as a property accessor if it represents a property.
             // We must also confirm that the property type is the same in both cases, because sometimes they aren't (e.g. IUIAutomationProxyFactoryEntry.ClassName).
-            if (this.TryGetPropertyAccessorInfo(methodDefinition.Method, originalIfaceName, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType) &&
+            if (this.TryGetPropertyAccessorInfo(methodDefinition.Method, originalIfaceName, context, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType) &&
                 declaredProperties.Contains(propertyName.Identifier.ValueText))
             {
                 StatementSyntax ThrowOnHRFailure(ExpressionSyntax hrExpression) => ExpressionStatement(InvocationExpression(
@@ -343,7 +345,7 @@ StatementSyntax InvokeVtblAndThrow() => ExpressionStatement(InvocationExpression
 
             if (ccwThisParameter is not null && !ccwMethodsToSkip.Contains(methodDefHandle))
             {
-                if (this.TryGetPropertyAccessorInfo(methodDefinition.Method, originalIfaceName, out propertyName, out accessorKind, out propertyType) &&
+                if (this.TryGetPropertyAccessorInfo(methodDefinition.Method, originalIfaceName, context, out propertyName, out accessorKind, out propertyType) &&
                     ifaceDeclaredProperties!.Contains(propertyName.Identifier.ValueText))
                 {
                     switch (accessorKind)
@@ -601,7 +603,7 @@ void AddCcwThunk(params StatementSyntax[] thunkInvokeAndReturn)
 
         var members = new List<MemberDeclarationSyntax>();
         var friendlyOverloads = new List<MethodDeclarationSyntax>();
-        ISet<string> declaredProperties = this.GetDeclarableProperties(allMethods.Select(this.Reader.GetMethodDefinition), actualIfaceName, allowNonConsecutiveAccessors: false);
+        ISet<string> declaredProperties = this.GetDeclarableProperties(allMethods.Select(this.Reader.GetMethodDefinition), actualIfaceName, allowNonConsecutiveAccessors: false, context);
 
         foreach (MethodDefinitionHandle methodDefHandle in allMethods)
         {
@@ -617,7 +619,7 @@ void AddCcwThunk(params StatementSyntax[] thunkInvokeAndReturn)
                 // Even if it could be represented as a property accessor, we cannot do so if a property by the same name was already declared in anything other than the previous row.
                 // Adding an accessor to a property later than the very next row would screw up the virtual method table ordering.
                 // We must also confirm that the property type is the same in both cases, because sometimes they aren't (e.g. IUIAutomationProxyFactoryEntry.ClassName).
-                if (this.TryGetPropertyAccessorInfo(methodDefinition, actualIfaceName, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType) && declaredProperties.Contains(propertyName.Identifier.ValueText))
+                if (this.TryGetPropertyAccessorInfo(methodDefinition, actualIfaceName, context, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType) && declaredProperties.Contains(propertyName.Identifier.ValueText))
                 {
                     AccessorDeclarationSyntax accessor = AccessorDeclaration(accessorKind.Value).WithSemicolonToken(Semicolon);
 
@@ -842,15 +844,15 @@ private bool UsePreserveSigForComMethod(MethodDefinition methodDefinition, Metho
             || this.options.ComInterop.PreserveSigMethods.Contains(ifaceName.ToString());
     }
 
-    private ISet<string> GetDeclarableProperties(IEnumerable<MethodDefinition> methods, string ifaceName, bool allowNonConsecutiveAccessors)
+    private ISet<string> GetDeclarableProperties(IEnumerable<MethodDefinition> methods, string ifaceName, bool allowNonConsecutiveAccessors, Context context)
     {
         Dictionary<string, (TypeSyntax Type, int Index)> goodProperties = new(StringComparer.Ordinal);
         HashSet<string> badProperties = new(StringComparer.Ordinal);
         int rowIndex = -1;
         foreach (MethodDefinition methodDefinition in methods)
         {
             rowIndex++;
-            if (this.TryGetPropertyAccessorInfo(methodDefinition, ifaceName, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType))
+            if (this.TryGetPropertyAccessorInfo(methodDefinition, ifaceName, context, out IdentifierNameSyntax? propertyName, out SyntaxKind? accessorKind, out TypeSyntax? propertyType))
             {
                 if (badProperties.Contains(propertyName.Identifier.ValueText))
                 {
@@ -886,11 +888,12 @@ void ReportBadProperty()
         return goodProperties.Count == 0 ? ImmutableHashSet<string>.Empty : new HashSet<string>(goodProperties.Keys, StringComparer.Ordinal);
     }
 
-    private bool TryGetPropertyAccessorInfo(MethodDefinition methodDefinition, string ifaceName, [NotNullWhen(true)] out IdentifierNameSyntax? propertyName, [NotNullWhen(true)] out SyntaxKind? accessorKind, [NotNullWhen(true)] out TypeSyntax? propertyType)
+    private bool TryGetPropertyAccessorInfo(MethodDefinition methodDefinition, string ifaceName, Context context, [NotNullWhen(true)] out IdentifierNameSyntax? propertyName, [NotNullWhen(true)] out SyntaxKind? accessorKind, [NotNullWhen(true)] out TypeSyntax? propertyType)
     {
         propertyName = null;
         accessorKind = null;
         propertyType = null;
+        TypeSyntaxSettings syntaxSettings = context.Filter(this.comSignatureTypeSettings);
 
         if ((methodDefinition.Attributes & MethodAttributes.SpecialName) != MethodAttributes.SpecialName)
         {
@@ -934,7 +937,8 @@ private bool TryGetPropertyAccessorInfo(MethodDefinition methodDefinition, strin
             }
 
             Parameter propertyTypeParameter = this.Reader.GetParameter(parameters.Skip(1).Single());
-            propertyType = signature.ParameterTypes[0].ToTypeSyntax(this.comSignatureTypeSettings, propertyTypeParameter.GetCustomAttributes(), propertyTypeParameter.Attributes).Type;
+            TypeHandleInfo propertyTypeInfo = signature.ParameterTypes[0];
+            propertyType = propertyTypeInfo.ToTypeSyntax(syntaxSettings, propertyTypeParameter.GetCustomAttributes(), propertyTypeParameter.Attributes).Type;
 
             if (isGetter)
             {
@@ -946,7 +950,7 @@ private bool TryGetPropertyAccessorInfo(MethodDefinition methodDefinition, strin
                     return false;
                 }
 
-                if (propertyType is PointerTypeSyntax propertyTypePointer)
+                if (propertyType is PointerTypeSyntax propertyTypePointer && (syntaxSettings.AllowMarshaling || !this.IsManagedType(propertyTypeInfo)))
                 {
                     propertyType = propertyTypePointer.ElementType;
                 }

src/Microsoft.Windows.CsWin32/Generator.Struct.cs

@@ -49,7 +49,28 @@ private StructDeclarationSyntax DeclareStruct(TypeDefinitionHandle typeDefHandle
                     CustomAttributeHandleCollection fieldAttributes = fieldDef.GetCustomAttributes();
                     TypeHandleInfo fieldTypeInfo = fieldDef.DecodeSignature(SignatureHandleProvider.Instance, null);
                     hasUtf16CharField |= fieldTypeInfo is PrimitiveTypeHandleInfo { PrimitiveTypeCode: PrimitiveTypeCode.Char };
-                    TypeSyntaxAndMarshaling fieldTypeSyntax = fieldTypeInfo.ToTypeSyntax(typeSettings, fieldAttributes);
+                    TypeSyntaxSettings thisFieldTypeSettings = typeSettings;
+
+                    // Do not qualify names of a type nested inside *this* struct, since this struct may or may not have a mangled name.
+                    if (thisFieldTypeSettings.QualifyNames && fieldTypeInfo is HandleTypeHandleInfo fieldHandleTypeInfo && this.IsNestedType(fieldHandleTypeInfo.Handle))
+                    {
+                        if (fieldHandleTypeInfo.Handle.Kind == HandleKind.TypeReference)
+                        {
+                            if (this.TryGetTypeDefHandle((TypeReferenceHandle)fieldHandleTypeInfo.Handle, out QualifiedTypeDefinitionHandle fieldTypeDefHandle) && fieldTypeDefHandle.Generator == this)
+                            {
+                                foreach (TypeDefinitionHandle nestedTypeHandle in typeDef.GetNestedTypes())
+                                {
+                                    if (fieldTypeDefHandle.DefinitionHandle == nestedTypeHandle)
+                                    {
+                                        thisFieldTypeSettings = thisFieldTypeSettings with { QualifyNames = false };
+                                        break;
+                                    }
+                                }
+                            }
+                        }
+                    }
+
+                    TypeSyntaxAndMarshaling fieldTypeSyntax = fieldTypeInfo.ToTypeSyntax(thisFieldTypeSettings, fieldAttributes);
                     (TypeSyntax FieldType, SyntaxList<MemberDeclarationSyntax> AdditionalMembers, AttributeSyntax? MarshalAsAttribute) fieldInfo = this.ReinterpretFieldType(fieldDef, fieldTypeSyntax.Type, fieldAttributes, context);
                     additionalMembers = additionalMembers.AddRange(fieldInfo.AdditionalMembers);
 
@@ -147,7 +168,7 @@ private StructDeclarationSyntax DeclareStruct(TypeDefinitionHandle typeDefHandle
 
         // If the field is a pointer to a COM interface (and we're using bona fide interfaces),
         // then we must type it as an array.
-        if (context.AllowMarshaling && fieldTypeHandleInfo is PointerTypeHandleInfo ptr3 && this.IsManagedType(ptr3.ElementType))
+        if (context.AllowMarshaling && fieldTypeHandleInfo is PointerTypeHandleInfo ptr3 && this.IsInterface(ptr3.ElementType))
         {
             return (ArrayType(ptr3.ElementType.ToTypeSyntax(typeSettings, null).Type).AddRankSpecifiers(ArrayRankSpecifier()), default(SyntaxList<MemberDeclarationSyntax>), marshalAs);
         }

src/Microsoft.Windows.CsWin32/Generator.cs

@@ -138,7 +138,7 @@ void AddSymbolIf(bool condition, string symbol)
         this.externReleaseSignatureTypeSettings = this.externSignatureTypeSettings with { PreferNativeInt = false, PreferMarshaledTypes = false };
         this.comSignatureTypeSettings = this.generalTypeSettings with { QualifyNames = true, PreferInOutRef = options.AllowMarshaling };
         this.extensionMethodSignatureTypeSettings = this.generalTypeSettings with { QualifyNames = true };
-        this.functionPointerTypeSettings = this.generalTypeSettings with { QualifyNames = true };
+        this.functionPointerTypeSettings = this.generalTypeSettings with { QualifyNames = true, AllowMarshaling = false };
         this.errorMessageTypeSettings = this.generalTypeSettings with { QualifyNames = true, Generator = null }; // Avoid risk of infinite recursion from errors in ToTypeSyntax
 
         this.methodsAndConstantsClassName = IdentifierName(options.ClassName);
@@ -1159,9 +1159,17 @@ private bool TryGetRenamedMethod(string methodName, [NotNullWhen(true)] out stri
                     StructDeclarationSyntax structDeclaration = this.DeclareStruct(typeDefHandle, context);
 
                     // Proactively generate all nested types as well.
+                    // If the outer struct is using ExplicitLayout, generate the nested types as unmanaged structs since that's what will be needed.
+                    Context nestedContext = context;
+                    bool explicitLayout = (typeDef.Attributes & TypeAttributes.ExplicitLayout) == TypeAttributes.ExplicitLayout;
+                    if (context.AllowMarshaling && explicitLayout)
+                    {
+                        nestedContext = nestedContext with { AllowMarshaling = false };
+                    }
+
                     foreach (TypeDefinitionHandle nestedHandle in typeDef.GetNestedTypes())
                     {
-                        if (this.RequestInteropTypeHelper(nestedHandle, context) is { } nestedType)
+                        if (this.RequestInteropTypeHelper(nestedHandle, nestedContext) is { } nestedType)
                         {
                             structDeclaration = structDeclaration.AddMembers(nestedType);
                         }
@@ -1201,7 +1209,7 @@ private bool TryGetRenamedMethod(string methodName, [NotNullWhen(true)] out stri
         }
         catch (Exception ex)
         {
-            throw new GenerationFailedException("Failed to generate " + this.Reader.GetString(typeDef.Name), ex);
+            throw new GenerationFailedException($"Failed to generate {this.Reader.GetString(typeDef.Name)}{(context.AllowMarshaling ? string.Empty : " (unmanaged)")}", ex);
         }
     }
 
@@ -1365,6 +1373,7 @@ private IEnumerable<NamespaceMetadata> GetNamespacesToSearch(string? @namespace)
         }
     }
 
+    [DebuggerDisplay($"AllowMarshaling: {{{nameof(AllowMarshaling)}}}")]
     internal record struct Context
     {
         /// <summary>

src/Microsoft.Windows.CsWin32/PointerTypeHandleInfo.cs

@@ -9,6 +9,12 @@ internal record PointerTypeHandleInfo(TypeHandleInfo ElementType) : TypeHandleIn
 
     internal override TypeSyntaxAndMarshaling ToTypeSyntax(TypeSyntaxSettings inputs, CustomAttributeHandleCollection? customAttributes, ParameterAttributes parameterAttributes)
     {
+        // We can't marshal a pointer exposed as a field, unless it's a pointer to an array.
+        if (inputs.AllowMarshaling && inputs.IsField && (customAttributes is null || inputs.Generator?.FindNativeArrayInfoAttribute(customAttributes.Value) is null))
+        {
+            inputs = inputs with { AllowMarshaling = false };
+        }
+
         TypeSyntaxAndMarshaling elementTypeDetails = this.ElementType.ToTypeSyntax(inputs with { PreferInOutRef = false }, customAttributes);
         if (elementTypeDetails.MarshalAsAttribute is object || inputs.Generator?.IsManagedType(this.ElementType) is true || (inputs.PreferInOutRef && this.ElementType is PrimitiveTypeHandleInfo { PrimitiveTypeCode: not PrimitiveTypeCode.Void }))
         {
@@ -68,13 +74,6 @@ internal override TypeSyntaxAndMarshaling ToTypeSyntax(TypeSyntaxSettings inputs
             return new TypeSyntaxAndMarshaling(PredefinedType(Token(SyntaxKind.ObjectKeyword)), new MarshalAsAttribute(UnmanagedType.IUnknown), null);
         }
 
-        // Since we'll be using pointers, we have to ensure the element type does not require any marshaling.
-        if (inputs.AllowMarshaling)
-        {
-            // Evidently all tests pass without actually doing this, so we'll leave it out for now.
-            ////elementTypeDetails = this.ElementType.ToTypeSyntax(inputs with { AllowMarshaling = false }, customAttributes);
-        }
-
         return new TypeSyntaxAndMarshaling(PointerType(elementTypeDetails.Type));
     }
 

test/GenerationSandbox.Tests/GeneratedForm.cs

@@ -7,6 +7,7 @@
 using Windows.Win32.Foundation;
 using Windows.Win32.Networking.ActiveDirectory;
 using Windows.Win32.System.Diagnostics.Debug;
+using Windows.Win32.System.Threading;
 
 #pragma warning disable CA1812 // dead code
 
@@ -65,4 +66,11 @@ private static void ZZStringUsed()
         Windows.Win32.UI.Shell.SHFILEOPSTRUCTW s = default;
         PCZZWSTR from = s.pFrom;
     }
+
+    private static void PROCESS_BASIC_INFORMATION_PebBaseAddressIsPointer()
+    {
+        PROCESS_BASIC_INFORMATION info = default;
+        PEB_unmanaged* p = null;
+        info.PebBaseAddress = p;
+    }
 }

test/GenerationSandbox.Tests/NativeMethods.txt

@@ -23,6 +23,7 @@ MainAVIHeader
 MAX_PATH
 NTSTATUS
 PathParseIconLocation
+PROCESS_BASIC_INFORMATION
 PZZSTR
 PZZWSTR
 RECT

test/Microsoft.Windows.CsWin32.Tests/COMTests.cs

@@ -250,6 +250,8 @@ public void InterestingComInterfaces(
             "IPicture", // An interface with properties that cannot be represented as properties.
             "ID2D1DeviceContext2", // CreateLookupTable3D takes fixed length arrays as parameters
             "IVPBaseConfig", // GetConnectInfo has a CountParamIndex that points to an [In, Out] parameter.
+            "IXAudio2SourceVoice", // Requires switch to unmanaged IXAudio2Voice struct which verifies type names retain the _unmanaged suffix everywhere required.
+            "MSP_EVENT_INFO", // Generates ITStream_unmanaged and ITTerminal_unmanaged
             "IWMDMDevice2")] // The GetSpecifyPropertyPages method has an NativeArrayInfo.CountParamIndex pointing at an [Out] parameter.
         string api,
         bool allowMarshaling)

test/Microsoft.Windows.CsWin32.Tests/StructTests.cs

@@ -117,4 +117,35 @@ public void FARPROC_GeneratedAsStruct(string tfm)
         BaseTypeDeclarationSyntax type = Assert.Single(this.FindGeneratedType("FARPROC"));
         Assert.IsType<StructDeclarationSyntax>(type);
     }
+
+    [Fact]
+    public void PointerFieldIsDeclaredAsPointer()
+    {
+        this.generator = this.CreateGenerator();
+        Assert.True(this.generator.TryGenerate("PROCESS_BASIC_INFORMATION", CancellationToken.None));
+        this.CollectGeneratedCode(this.generator);
+        this.AssertNoDiagnostics();
+
+        var type = (StructDeclarationSyntax)Assert.Single(this.FindGeneratedType("PROCESS_BASIC_INFORMATION"));
+        FieldDeclarationSyntax field = Assert.Single(type.Members.OfType<FieldDeclarationSyntax>(), m => m.Declaration.Variables.Any(v => v.Identifier.ValueText == "PebBaseAddress"));
+        Assert.IsType<PointerTypeSyntax>(field.Declaration.Type);
+    }
+
+    [Theory]
+    [CombinatorialData]
+    public void InterestingStructs(
+        [CombinatorialValues(
+        "WSD_EVENT")] // has a pointer field to a managed struct
+        string name,
+        bool allowMarshaling)
+    {
+        var options = DefaultTestGeneratorOptions with
+        {
+            AllowMarshaling = allowMarshaling,
+        };
+        this.generator = this.CreateGenerator(options);
+        Assert.True(this.generator.TryGenerate(name, CancellationToken.None));
+        this.CollectGeneratedCode(this.generator);
+        this.AssertNoDiagnostics();
+    }
 }