Add fallback logic for specialized RCW marshalling for unsealed types

src/Tests/TestComponentCSharp/Class.cpp

@@ -1,6 +1,7 @@
 #include "pch.h"
 #include "Class.h"
 #include "Class.g.cpp"
+#include "CustomEquals.h"
 
 using namespace std::chrono;
 
@@ -2121,5 +2122,10 @@ namespace winrt::TestComponentCSharp::implementation
 
         return winrt::make<bad_runtime_classname>();
     }
+
+    winrt::TestComponentCSharp::UnSealedCustomEquals Class::NonProjectedClassInstance()
+    {
+        return winrt::make<NonProjectedDerivedCustomEquals>();
+    }
 }
 

src/Tests/TestComponentCSharp/Class.h

@@ -488,6 +488,7 @@ namespace winrt::TestComponentCSharp::implementation
         void RaiseCanExecuteChanged();
 
         static Windows::Foundation::IInspectable BadRuntimeClassName();
+        static winrt::TestComponentCSharp::UnSealedCustomEquals NonProjectedClassInstance();
     };
 }
 

src/Tests/TestComponentCSharp/CustomEquals.cpp

@@ -67,7 +67,7 @@ namespace winrt::TestComponentCSharp::implementation
 
     int32_t UnSealedCustomEquals::Value()
     {
-        return value;
+        return value * factor;
     }
 
     void UnSealedCustomEquals::Value(int32_t value)

src/Tests/TestComponentCSharp/CustomEquals.h

@@ -40,6 +40,8 @@ namespace winrt::TestComponentCSharp::implementation
         int32_t Value();
         void Value(int32_t value);
         int32_t GetHashCode();
+    protected:
+        int32_t factor = 1;
 
     private:
         int32_t value;
@@ -53,6 +55,19 @@ namespace winrt::TestComponentCSharp::implementation
         int32_t GetHashCode();
         bool Equals(winrt::TestComponentCSharp::UnSealedCustomEquals const& other);
     };
+
+    struct NonProjectedDerivedCustomEquals : winrt::implements<NonProjectedDerivedCustomEquals, TestComponentCSharp::implementation::UnSealedCustomEquals>
+    {
+        NonProjectedDerivedCustomEquals()
+        {
+            factor = 2;
+        }
+
+        hstring GetRuntimeClassName() const override
+        {
+            return L"TestComponentCSharp.NonProjectedDerivedCustomEquals";
+        }
+    };
 }
 namespace winrt::TestComponentCSharp::factory_implementation
 {

src/Tests/TestComponentCSharp/TestComponentCSharp.idl

@@ -152,6 +152,15 @@ namespace TestComponentCSharp
         static ISingleton Instance;
     }
 
+    [default_interface]
+    unsealed runtimeclass UnSealedCustomEquals
+    {
+        Int32 Value{ get; set; };
+
+        UnSealedCustomEquals();
+        Int32 GetHashCode();
+    }
+
     [default_interface, gc_pressure(Windows.Foundation.Metadata.GCPressureAmount.High)]
     runtimeclass Class :
         Windows.Foundation.IStringable
@@ -496,6 +505,7 @@ namespace TestComponentCSharp
         void RaiseCanExecuteChanged();
 
         static Object BadRuntimeClassName{ get; };
+        static UnSealedCustomEquals NonProjectedClassInstance{ get; };
     }
 
     runtimeclass ABCDEFGHIJKLMNOPQRSTUVQXYZabcdefghijklmnopqrstuvqxyzABCDEFGHIJKLMNOPQRSTUVQXYZabcdefghijklmnopqrstuvqxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
@@ -675,15 +685,6 @@ And this is another one"
         Int32 Equals(CustomEquals2 other);
     }
 
-    [default_interface]
-    unsealed runtimeclass UnSealedCustomEquals
-    {
-        Int32 Value{ get; set; };
-
-        UnSealedCustomEquals();
-        Int32 GetHashCode();
-    }
-
     [default_interface]
     runtimeclass DerivedCustomEquals : UnSealedCustomEquals
     {

src/Tests/UnitTest/TestComponentCSharp_Tests.cs

@@ -3897,5 +3897,14 @@ public void TestTimeSpanDictionary()
                 Assert.Equal(TimeSpan.FromMinutes(1), entries.Value - entries.Key);
             }
         }
+
+        [Fact]
+        public void TestNontProjectedClassAsBaseClass()
+        {
+            UnSealedCustomEquals customEquals = Class.NonProjectedClassInstance;
+            customEquals.Value = 3;
+            // Non projected class changes the behavior of the Value property to double it.
+            Assert.Equal(6, customEquals.Value);
+        }
     }
 }

src/WinRT.Interop.Generator/Builders/InteropTypeDefinitionBuilder.cs

@@ -219,6 +219,36 @@ private static void ComWrappersCallback(
                 { Ret }
             }
         };
+
+        // Define the 'CreateObject' method as follows:
+        //
+        // public static object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+        MethodDefinition createObjectMethod = new(
+            name: "CreateObject"u8,
+            attributes: MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Static,
+            signature: MethodSignature.CreateStatic(
+                returnType: module.CorLibTypeFactory.Object,
+                parameterTypes: [
+                    module.CorLibTypeFactory.Void.MakePointerType(),
+                    interopReferences.CreatedWrapperFlags.Import(module).MakeByReferenceType()]))
+        {
+            CilOutParameterIndices = [2],
+            CilInstructions =
+            {
+                // Create the 'WindowsRuntimeObjectReference' instance and use it to create a 'NativeObject' instance
+                { Ldarg_0 },
+                { Call, get_IidMethod },
+                { Ldarg_1 },
+                { Call, interopReferences.WindowsRuntimeComWrappersMarshalCreateObjectReferenceUnsafe.Import(module) },
+                { Newobj, nativeObjectType.GetMethod(".ctor"u8) },
+                { Ret }
+            }
+        };
+
+        // Add and implement 'CreateObject'
+        callbackType.AddMethodImplementation(
+            declaration: interopReferences.IWindowsRuntimeUnsealedObjectComWrappersCallbackCreateObject.Import(module),
+            method: createObjectMethod);
     }
 
     /// <summary>

src/WinRT.Interop.Generator/References/InteropReferences.cs

@@ -2047,6 +2047,16 @@ public InteropReferences(
                 _corLibTypeFactory.Object.MakeByReferenceType(),
                 CreatedWrapperFlags.ToValueTypeSignature().MakeByReferenceType()]));
 
+    /// <summary>
+    /// Gets the <see cref="MemberReference"/> for <c>WindowsRuntime.InteropServices.IWindowsRuntimeUnsealedObjectComWrappersCallback.CreateObject</c>.
+    /// </summary>
+    public MemberReference IWindowsRuntimeUnsealedObjectComWrappersCallbackCreateObject => field ??= IWindowsRuntimeUnsealedObjectComWrappersCallback
+        .CreateMemberReference("CreateObject"u8, MethodSignature.CreateStatic(
+            returnType: _corLibTypeFactory.Object,
+            parameterTypes: [
+                _corLibTypeFactory.Void.MakePointerType(),
+                CreatedWrapperFlags.ToValueTypeSignature().MakeByReferenceType()]));
+
     /// <summary>
     /// Gets the <see cref="MemberReference"/> for <c>WindowsRuntime.InteropServices.IWindowsRuntimeArrayComWrappersCallback.CreateArray</c>.
     /// </summary>

src/WinRT.Runtime2/ABI/System/Collections/IEnumerable.cs

@@ -85,6 +85,17 @@ public static unsafe bool TryCreateObject(
 
         return false;
     }
+
+    /// <inheritdoc/>
+    public static unsafe object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+    {
+        WindowsRuntimeObjectReference valueReference = WindowsRuntimeComWrappersMarshal.CreateObjectReferenceUnsafe(
+            externalComObject: value,
+            iid: in WellKnownWindowsInterfaceIIDs.IID_IBindableIterable,
+            wrapperFlags: out wrapperFlags);
+
+        return new WindowsRuntimeEnumerable(valueReference);
+    }
 }
 
 /// <summary>

src/WinRT.Runtime2/ABI/System/Collections/IEnumerator.cs

@@ -85,6 +85,17 @@ public static unsafe bool TryCreateObject(
 
         return false;
     }
+
+    /// <inheritdoc/>
+    public static unsafe object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+    {
+        WindowsRuntimeObjectReference valueReference = WindowsRuntimeComWrappersMarshal.CreateObjectReferenceUnsafe(
+            externalComObject: value,
+            iid: in WellKnownWindowsInterfaceIIDs.IID_IBindableIterator,
+            wrapperFlags: out wrapperFlags);
+
+        return new WindowsRuntimeEnumerator(valueReference);
+    }
 }
 
 /// <summary>

src/WinRT.Runtime2/ABI/System/Collections/IList.cs

@@ -89,6 +89,17 @@ public static unsafe bool TryCreateObject(
 
         return false;
     }
+
+    /// <inheritdoc/>
+    public static unsafe object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+    {
+        WindowsRuntimeObjectReference valueReference = WindowsRuntimeComWrappersMarshal.CreateObjectReferenceUnsafe(
+            externalComObject: value,
+            iid: in WellKnownWindowsInterfaceIIDs.IID_IBindableVector,
+            wrapperFlags: out wrapperFlags);
+
+        return new WindowsRuntimeList(valueReference);
+    }
 }
 
 /// <summary>

src/WinRT.Runtime2/ABI/Windows.Foundation/IAsyncAction.cs

@@ -72,6 +72,17 @@ public static bool TryCreateObject(
 
         return false;
     }
+
+    /// <inheritdoc/>
+    public static object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+    {
+        WindowsRuntimeObjectReference objectReference = WindowsRuntimeComWrappersMarshal.CreateObjectReferenceUnsafe(
+            externalComObject: value,
+            iid: in WellKnownWindowsInterfaceIIDs.IID_IAsyncAction,
+            wrapperFlags: out wrapperFlags);
+
+        return new WindowsRuntimeAsyncAction(objectReference);
+    }
 }
 
 /// <summary>

src/WinRT.Runtime2/InteropServices/Callbacks/IWindowsRuntimeUnsealedObjectComWrappersCallback.cs

@@ -48,4 +48,18 @@ static abstract bool TryCreateObject(
         ReadOnlySpan<char> runtimeClassName,
         [NotNullWhen(true)] out object? wrapperObject,
         out CreatedWrapperFlags wrapperFlags);
+
+    /// <summary>
+    /// Creates a managed Windows Runtime object for a given native object.
+    /// </summary>
+    /// <param name="value">The input native object to marshal.</param>
+    /// <param name="wrapperFlags">Flags used to describe the created wrapper object.</param>
+    /// <returns>The resulting managed Windows Runtime object.</returns>
+    /// <remarks>
+    /// This method is equivalent to <see cref="IWindowsRuntimeObjectComWrappersCallback.CreateObject"/>, but for unsealed
+    /// types, and is called if <see cref="TryCreateObject"/> failed but not other more specific RCW type could be resolved.
+    /// Additionally, it can also be called if <see cref="IInspectableVftbl.GetRuntimeClassNameUnsafe"/> fails for any reason.
+    /// </remarks>
+    /// <seealso cref="IWindowsRuntimeObjectComWrappersCallback.CreateObject"/>
+    static abstract object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags);
 }

src/WinRT.Runtime2/InteropServices/Callbacks/WindowsRuntimeUnsealedObjectComWrappersCallback.cs

@@ -29,6 +29,9 @@ public abstract bool TryCreateObject(
         ReadOnlySpan<char> runtimeClassName,
         [NotNullWhen(true)] out object? wrapperObject,
         out CreatedWrapperFlags wrapperFlags);
+
+    /// <inheritdoc cref="IWindowsRuntimeUnsealedObjectComWrappersCallback.CreateObject"/>
+    public abstract object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags);
 }
 
 /// <summary>
@@ -52,4 +55,10 @@ public override unsafe bool TryCreateObject(
     {
         return TCallback.TryCreateObject(value, runtimeClassName, out wrapperObject, out wrapperFlags);
     }
+
+    /// <inheritdoc/>
+    public override unsafe object CreateObject(void* value, out CreatedWrapperFlags wrapperFlags)
+    {
+        return TCallback.CreateObject(value, out wrapperFlags);
+    }
 }