Apply ComVisible attribute to embedded value types.

Fixes #16177.

src/Compilers/CSharp/Portable/Emitter/NoPia/EmbeddedType.cs

@@ -206,13 +206,6 @@ protected override IEnumerable<CSharpAttributeData> GetCustomAttributesToEmit(Mo
             return UnderlyingNamedType.GetCustomAttributesToEmit(compilationState);
         }
 
-        protected override CSharpAttributeData CreateCompilerGeneratedAttribute()
-        {
-            Debug.Assert(WellKnownMembers.IsSynthesizedAttributeOptional(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor));
-            var compilation = TypeManager.ModuleBeingBuilt.Compilation;
-            return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor);
-        }
-
         protected override CSharpAttributeData CreateTypeIdentifierAttribute(bool hasGuid, SyntaxNode syntaxNodeOpt, DiagnosticBag diagnostics)
         {
             var member = hasGuid ?

src/Compilers/CSharp/Portable/Emitter/NoPia/EmbeddedTypesManager.cs

@@ -565,5 +565,22 @@ protected override EmbeddedType GetEmbeddedTypeForMember(Symbol member, SyntaxNo
         {
             return underlyingParameters.SelectAsArray((p, c) => new EmbeddedParameter(c, p), containingPropertyOrMethod);
         }
+
+        protected override CSharpAttributeData CreateCompilerGeneratedAttribute()
+        {
+            Debug.Assert(WellKnownMembers.IsSynthesizedAttributeOptional(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor));
+            var compilation = ModuleBeingBuilt.Compilation;
+            return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor);
+        }
+
+        protected override CSharpAttributeData CreateComVisibleAttribute()
+        {
+            var compilation = ModuleBeingBuilt.Compilation;
+            return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_InteropServices_ComVisibleAttribute__ctor,
+                                                      ImmutableArray.Create(new TypedConstant(compilation.GetSpecialType(SpecialType.System_Boolean),
+                                                                                              TypedConstantKind.Primitive,
+                                                                                              value:true)), 
+                                                      isOptionalUse:true);
+        }
     }
 }

src/Compilers/CSharp/Portable/Symbols/Compilation_WellKnownMembers.cs

@@ -306,10 +306,14 @@ internal static Symbol GetRuntimeMember(NamedTypeSymbol declaringType, ref Membe
         /// If the well-known member does not exist in the compilation then no attribute
         /// will be synthesized.
         /// </param>
+        /// <param name="isOptionalUse">
+        /// Indicates if this particular attribute application should be considered optional.
+        /// </param>
         internal SynthesizedAttributeData TrySynthesizeAttribute(
             WellKnownMember constructor,
             ImmutableArray<TypedConstant> arguments = default(ImmutableArray<TypedConstant>),
-            ImmutableArray<KeyValuePair<WellKnownMember, TypedConstant>> namedArguments = default(ImmutableArray<KeyValuePair<WellKnownMember, TypedConstant>>))
+            ImmutableArray<KeyValuePair<WellKnownMember, TypedConstant>> namedArguments = default(ImmutableArray<KeyValuePair<WellKnownMember, TypedConstant>>),
+            bool isOptionalUse = false)
         {
             DiagnosticInfo diagnosticInfo;
             var ctorSymbol = (MethodSymbol)Binder.GetWellKnownTypeMember(this, constructor, out diagnosticInfo, isOptional: true);
@@ -317,7 +321,7 @@ internal static Symbol GetRuntimeMember(NamedTypeSymbol declaringType, ref Membe
             if ((object)ctorSymbol == null)
             {
                 // if this assert fails, UseSiteErrors for "member" have not been checked before emitting ...
-                Debug.Assert(WellKnownMembers.IsSynthesizedAttributeOptional(constructor));
+                Debug.Assert(isOptionalUse || WellKnownMembers.IsSynthesizedAttributeOptional(constructor));
                 return null;
             }
 

src/Compilers/CSharp/Test/Emit/Emit/NoPiaEmbedTypes.cs

@@ -1201,9 +1201,10 @@ public void M6(ITest26 x)
                     Assert.Equal(TypeAttributes.Public | TypeAttributes.SequentialLayout | TypeAttributes.Class | TypeAttributes.Sealed | TypeAttributes.AnsiClass | TypeAttributes.BeforeFieldInit, test2.Flags);
 
                     attributes = test2.GetAttributes();
-                    Assert.Equal(2, attributes.Length);
+                    Assert.Equal(3, attributes.Length);
                     Assert.Equal("System.Runtime.CompilerServices.CompilerGeneratedAttribute", attributes[0].ToString());
                     Assert.Equal(@"System.Runtime.InteropServices.TypeIdentifierAttribute(""f9c2d51d-4f44-45f0-9eda-c9d599b58257"", ""Test2"")", attributes[1].ToString());
+                    Assert.Equal("System.Runtime.InteropServices.ComVisibleAttribute(true)", attributes[2].ToString());
 
                     var itest3 = module.GlobalNamespace.GetTypeMembers("ITest3").Single();
                     Assert.Equal(TypeKind.Interface, itest3.TypeKind);
@@ -1261,9 +1262,10 @@ public void M6(ITest26 x)
                     Assert.Equal(TypeAttributes.Public | TypeAttributes.AutoLayout | TypeAttributes.Class | TypeAttributes.Sealed | TypeAttributes.AnsiClass, test9.Flags);
 
                     attributes = test9.GetAttributes();
-                    Assert.Equal(2, attributes.Length);
+                    Assert.Equal(3, attributes.Length);
                     Assert.Equal("System.Runtime.CompilerServices.CompilerGeneratedAttribute", attributes[0].ToString());
                     Assert.Equal(@"System.Runtime.InteropServices.TypeIdentifierAttribute(""f9c2d51d-4f44-45f0-9eda-c9d599b58257"", ""Test9"")", attributes[1].ToString());
+                    Assert.Equal("System.Runtime.InteropServices.ComVisibleAttribute(true)", attributes[2].ToString());
 
                     var fieldToEmit = test9.GetFieldsToEmit().ToArray().AsImmutableOrNull();
                     Assert.Equal(3, fieldToEmit.Length);

src/Compilers/Core/Portable/Emit/NoPia/CommonEmbeddedType.cs

@@ -68,7 +68,6 @@ protected CommonEmbeddedType(TEmbeddedTypesManager typeManager, TNamedTypeSymbol
             protected abstract bool IsSealed { get; }
             protected abstract TypeLayout? GetTypeLayoutIfStruct();
             protected abstract System.Runtime.InteropServices.CharSet StringFormat { get; }
-            protected abstract TAttributeData CreateCompilerGeneratedAttribute();
             protected abstract TAttributeData CreateTypeIdentifierAttribute(bool hasGuid, TSyntaxNode syntaxNodeOpt, DiagnosticBag diagnostics);
             protected abstract void EmbedDefaultMembers(string defaultMember, TSyntaxNode syntaxNodeOpt, DiagnosticBag diagnostics);
             protected abstract IEnumerable<TAttributeData> GetCustomAttributesToEmit(TModuleCompilationState compilationState);
@@ -85,7 +84,7 @@ private ImmutableArray<TAttributeData> GetAttributes(TModuleCompilationState com
 
                 // Put the CompilerGenerated attribute on the NoPIA types we define so that 
                 // static analysis tools (e.g. fxcop) know that they can be skipped
-                builder.AddOptional(CreateCompilerGeneratedAttribute());
+                builder.AddOptional(TypeManager.CreateCompilerGeneratedAttribute());
 
                 // Copy some of the attributes.
 
@@ -204,6 +203,11 @@ private ImmutableArray<TAttributeData> GetAttributes(TModuleCompilationState com
 
                 builder.AddOptional(CreateTypeIdentifierAttribute(hasGuid && IsInterface, syntaxNodeOpt, diagnostics));
 
+                if (UnderlyingNamedType.IsValueType)
+                {
+                    builder.AddOptional(TypeManager.CreateComVisibleAttribute());
+                }
+
                 return builder.ToImmutableAndFree();
             }
 

src/Compilers/Core/Portable/Emit/NoPia/EmbeddedTypesManager.cs

@@ -155,6 +155,8 @@ internal bool IsTargetAttribute(TSymbol underlyingSymbol, TAttributeData attrDat
         protected abstract void OnGetTypesCompleted(ImmutableArray<TEmbeddedType> types, DiagnosticBag diagnostics);
         protected abstract void ReportNameCollisionBetweenEmbeddedTypes(TEmbeddedType typeA, TEmbeddedType typeB, DiagnosticBag diagnostics);
         protected abstract void ReportNameCollisionWithAlreadyDeclaredType(TEmbeddedType type, DiagnosticBag diagnostics);
+        protected abstract TAttributeData CreateCompilerGeneratedAttribute();
+        protected abstract TAttributeData CreateComVisibleAttribute();
 
         private sealed class TypeComparer : IComparer<TEmbeddedType>
         {

src/Compilers/VisualBasic/Portable/Emit/NoPia/EmbeddedType.vb

@@ -158,12 +158,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Emit.NoPia
             Return UnderlyingNamedType.GetCustomAttributesToEmit(compilationState)
         End Function
 
-        Protected Overrides Function CreateCompilerGeneratedAttribute() As VisualBasicAttributeData
-            Debug.Assert(WellKnownMembers.IsSynthesizedAttributeOptional(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor))
-            Dim compilation = TypeManager.ModuleBeingBuilt.Compilation
-            Return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor)
-        End Function
-
         Protected Overrides Function CreateTypeIdentifierAttribute(hasGuid As Boolean, syntaxNodeOpt As SyntaxNode, diagnostics As DiagnosticBag) As VisualBasicAttributeData
             Dim member = If(hasGuid,
                 WellKnownMember.System_Runtime_InteropServices_TypeIdentifierAttribute__ctor,

src/Compilers/VisualBasic/Portable/Emit/NoPia/EmbeddedTypesManager.vb

@@ -488,6 +488,21 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Emit.NoPia
             Return underlyingParameters.SelectAsArray(Function(parameter, container) New EmbeddedParameter(container, parameter), containingPropertyOrMethod)
         End Function
 
+        Protected Overrides Function CreateCompilerGeneratedAttribute() As VisualBasicAttributeData
+            Debug.Assert(WellKnownMembers.IsSynthesizedAttributeOptional(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor))
+            Dim compilation = ModuleBeingBuilt.Compilation
+            Return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor)
+        End Function
+
+        Protected Overrides Function CreateComVisibleAttribute() As VisualBasicAttributeData
+            Dim compilation = ModuleBeingBuilt.Compilation
+            Return compilation.TrySynthesizeAttribute(WellKnownMember.System_Runtime_InteropServices_ComVisibleAttribute__ctor,
+                                                      ImmutableArray.Create(New TypedConstant(compilation.GetSpecialType(SpecialType.System_Boolean),
+                                                                                              TypedConstantKind.Primitive,
+                                                                                              value:=True)),
+                                                      isOptionalUse:=True)
+        End Function
+
     End Class
 
 End Namespace

src/Compilers/VisualBasic/Portable/Symbols/WellKnownMembers.vb

@@ -136,15 +136,20 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         ''' If the well-known member does Not exist in the compilation then no attribute
         ''' will be synthesized.
         ''' </param>
+        ''' <param name="isOptionalUse">
+        ''' Indicates if this particular attribute application should be considered optional.
+        ''' </param>
         Friend Function TrySynthesizeAttribute(
             constructor As WellKnownMember,
             Optional arguments As ImmutableArray(Of TypedConstant) = Nothing,
-            Optional namedArguments As ImmutableArray(Of KeyValuePair(Of WellKnownMember, TypedConstant)) = Nothing) As SynthesizedAttributeData
+            Optional namedArguments As ImmutableArray(Of KeyValuePair(Of WellKnownMember, TypedConstant)) = Nothing,
+            Optional isOptionalUse As Boolean = False
+        ) As SynthesizedAttributeData
 
             Dim constructorSymbol = TryCast(GetWellKnownTypeMember(constructor), MethodSymbol)
             If constructorSymbol Is Nothing OrElse
                Binder.GetUseSiteErrorForWellKnownTypeMember(constructorSymbol, constructor, False) IsNot Nothing Then
-                Return ReturnNothingOrThrowIfAttributeNonOptional(constructor)
+                Return ReturnNothingOrThrowIfAttributeNonOptional(constructor, isOptionalUse)
             End If
 
             If arguments.IsDefault Then
@@ -172,8 +177,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return New SynthesizedAttributeData(constructorSymbol, arguments, namedStringArguments)
         End Function
 
-        Private Function ReturnNothingOrThrowIfAttributeNonOptional(constructor As WellKnownMember) As SynthesizedAttributeData
-            If WellKnownMembers.IsSynthesizedAttributeOptional(constructor) Then
+        Private Function ReturnNothingOrThrowIfAttributeNonOptional(constructor As WellKnownMember, Optional isOptionalUse As Boolean = False) As SynthesizedAttributeData
+            If isOptionalUse OrElse WellKnownMembers.IsSynthesizedAttributeOptional(constructor) Then
                 Return Nothing
             Else
                 Throw ExceptionUtilities.Unreachable

src/Compilers/VisualBasic/Test/Emit/Emit/NoPiaEmbedTypes.vb

@@ -1033,9 +1033,10 @@ End Class
                                                            Assert.Equal(TypeAttributes.Public Or TypeAttributes.SequentialLayout Or TypeAttributes.Class Or TypeAttributes.Sealed Or TypeAttributes.AnsiClass Or TypeAttributes.BeforeFieldInit, test2.TypeDefFlags)
 
                                                            attributes = test2.GetAttributes()
-                                                           Assert.Equal(2, attributes.Length)
+                                                           Assert.Equal(3, attributes.Length)
                                                            Assert.Equal("System.Runtime.CompilerServices.CompilerGeneratedAttribute", attributes(0).ToString())
                                                            Assert.Equal("System.Runtime.InteropServices.TypeIdentifierAttribute(""f9c2d51d-4f44-45f0-9eda-c9d599b58257"", ""Test2"")", attributes(1).ToString())
+                                                           Assert.Equal("System.Runtime.InteropServices.ComVisibleAttribute(True)", attributes(2).ToString())
 
                                                            Dim itest3 = [module].GlobalNamespace.GetMember(Of NamedTypeSymbol)("ITest3")
                                                            Assert.Equal(TypeKind.Interface, itest3.TypeKind)
@@ -1093,9 +1094,10 @@ End Class
                                                            Assert.Equal(TypeAttributes.Public Or TypeAttributes.AutoLayout Or TypeAttributes.Class Or TypeAttributes.Sealed Or TypeAttributes.AnsiClass, test9.TypeDefFlags)
 
                                                            attributes = test9.GetAttributes()
-                                                           Assert.Equal(2, attributes.Length)
+                                                           Assert.Equal(3, attributes.Length)
                                                            Assert.Equal("System.Runtime.CompilerServices.CompilerGeneratedAttribute", attributes(0).ToString())
                                                            Assert.Equal("System.Runtime.InteropServices.TypeIdentifierAttribute(""f9c2d51d-4f44-45f0-9eda-c9d599b58257"", ""Test9"")", attributes(1).ToString())
+                                                           Assert.Equal("System.Runtime.InteropServices.ComVisibleAttribute(True)", attributes(2).ToString())
 
                                                            Dim fieldToEmit = test9.GetFieldsToEmit().ToArray().AsImmutableOrNull()
                                                            Assert.Equal(3, fieldToEmit.Length)