Add scalar IReference<TypeName>/IReference<HResult> projection tests

Add members to TestComponentCSharp exercising the scalar IReference<T>
projection for the two WinRT value types that map to .NET reference types:
IReference<Windows.UI.Xaml.Interop.TypeName> -> System.Type and
IReference<Windows.Foundation.HResult> -> System.Exception.

Each adds a native-boxed property (BoxedTypeName / BoxedHResult) and a
round-trip method (RoundtripTypeName / RoundtripHResult), with matching
UnitTest coverage including the null case.

These tests fail to build until the projection writer stops emitting the
invalid Nullable<Type> / Nullable<Exception> for these instantiations.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Sergio0694

src/Tests/TestComponentCSharp/Class.cpp

@@ -1891,6 +1891,26 @@ namespace winrt::TestComponentCSharp::implementation
         return type.Name;
     }
 
+    IReference<Windows::UI::Xaml::Interop::TypeName> Class::BoxedTypeName()
+    {
+        return winrt::box_value(winrt::xaml_typename<winrt::TestComponentCSharp::Class>()).as<IReference<Windows::UI::Xaml::Interop::TypeName>>();
+    }
+
+    IReference<Windows::UI::Xaml::Interop::TypeName> Class::RoundtripTypeName(IReference<Windows::UI::Xaml::Interop::TypeName> const& value)
+    {
+        return value;
+    }
+
+    IReference<winrt::hresult> Class::BoxedHResult()
+    {
+        return winrt::box_value(winrt::error_invalid_argument).as<IReference<winrt::hresult>>();
+    }
+
+    IReference<winrt::hresult> Class::RoundtripHResult(IReference<winrt::hresult> const& value)
+    {
+        return value;
+    }
+
     WF::IInspectable Class::EmptyString()
     {
         return winrt::box_value(hstring{});

src/Tests/TestComponentCSharp/Class.h

@@ -441,6 +441,12 @@ namespace winrt::TestComponentCSharp::implementation
         static bool VerifyTypeIsThisClassType(Windows::UI::Xaml::Interop::TypeName const& type_name);
         static hstring GetTypeNameForType(Windows::UI::Xaml::Interop::TypeName const& type);
 
+        static Windows::Foundation::IReference<Windows::UI::Xaml::Interop::TypeName> BoxedTypeName();
+        static Windows::Foundation::IReference<Windows::UI::Xaml::Interop::TypeName> RoundtripTypeName(Windows::Foundation::IReference<Windows::UI::Xaml::Interop::TypeName> const& value);
+
+        static Windows::Foundation::IReference<winrt::hresult> BoxedHResult();
+        static Windows::Foundation::IReference<winrt::hresult> RoundtripHResult(Windows::Foundation::IReference<winrt::hresult> const& value);
+
         static Windows::Foundation::IInspectable EmptyString();
         static Windows::Foundation::IInspectable BoxedDelegate();
         static Windows::Foundation::IInspectable BoxedEnum();

src/Tests/TestComponentCSharp/TestComponentCSharp.idl

@@ -520,6 +520,16 @@ namespace TestComponentCSharp
 
         static String GetTypeNameForType(Windows.UI.Xaml.Interop.TypeName type);
 
+        // IReference<WUX.Interop.TypeName> projects to System.Type (TypeName is a WinRT value type but
+        // projects to the reference type System.Type, so it must project as 'Type', not 'Nullable<Type>').
+        static Windows.Foundation.IReference<Windows.UI.Xaml.Interop.TypeName> BoxedTypeName{ get; };
+        static Windows.Foundation.IReference<Windows.UI.Xaml.Interop.TypeName> RoundtripTypeName(Windows.Foundation.IReference<Windows.UI.Xaml.Interop.TypeName> value);
+
+        // IReference<HResult> projects to System.Exception (HResult is a WinRT value type but projects to
+        // the reference type System.Exception, so it must project as 'Exception', not 'Nullable<Exception>').
+        static Windows.Foundation.IReference<Windows.Foundation.HResult> BoxedHResult{ get; };
+        static Windows.Foundation.IReference<Windows.Foundation.HResult> RoundtripHResult(Windows.Foundation.IReference<Windows.Foundation.HResult> value);
+
         // Other
         static Object EmptyString { get; };
 

src/Tests/UnitTest/TestComponentCSharp_Tests.cs

@@ -3758,6 +3758,34 @@ public void ProjectedTypeInfo()
             Assert.IsTrue(Class.VerifyTypeIsReferenceInt32Type(typeof(int?)));
         }
 
+        [TestMethod]
+        public void ReferenceTypeNameProjectsAsType()
+        {
+            // 'IReference<WUX.Interop.TypeName>' projects to 'System.Type', not the invalid 'Nullable<Type>'
+            // (TypeName is a WinRT value type, but it projects to the reference type 'System.Type'). The boxed
+            // value round-trips through the native boundary as a 'Type', including the null case.
+            Assert.AreEqual(typeof(Class), Class.BoxedTypeName);
+
+            Assert.AreEqual(typeof(int), Class.RoundtripTypeName(typeof(int)));
+            Assert.AreEqual(typeof(Class), Class.RoundtripTypeName(typeof(Class)));
+            Assert.IsNull(Class.RoundtripTypeName(null));
+        }
+
+        [TestMethod]
+        public void ReferenceHResultProjectsAsException()
+        {
+            // 'IReference<HResult>' projects to 'System.Exception', not the invalid 'Nullable<Exception>'
+            // (HResult is a WinRT value type, but it projects to the reference type 'System.Exception'). The
+            // boxed value round-trips through the native boundary as an 'Exception', including the null case.
+            Exception boxed = Class.BoxedHResult;
+
+            Assert.IsNotNull(boxed);
+            Assert.AreEqual(unchecked((int)0x80070057), boxed.HResult); // E_INVALIDARG
+
+            Assert.IsInstanceOfType<ArgumentOutOfRangeException>(Class.RoundtripHResult(new ArgumentOutOfRangeException()));
+            Assert.IsNull(Class.RoundtripHResult(null));
+        }
+
         [TestMethod]
         public void TypeInfoGenerics()
         {