Default Interface COM testing project (#23195)

* Add tests for native COM client consuming managed COM server that
  consumes interfaces with default implementation.

14 files changed, 396 insertions, 93 deletions

diff --git a/tests/issues.targets b/tests/issues.targets
index eb34df3ca6..56b9dc4a7c 100644
--- a/tests/issues.targets
+++ b/tests/issues.targets
@@ -330,6 +330,9 @@
         <ExcludeList Include="$(XunitTestBinBase)/Interop/COM/NativeClients/Licensing/*">
             <Issue>20682</Issue>
         </ExcludeList>
+        <ExcludeList Include="$(XunitTestBinBase)/Interop/COM/NativeClients/DefaultInterfaces/*">
+            <Issue>20682</Issue>
+        </ExcludeList>
         <ExcludeList Include="$(XunitTestBinBase)/Interop/COM/NETClients/IDispatch/NETClientIDispatch/*">
             <Issue>20682</Issue>
         </ExcludeList>
diff --git a/tests/src/Interop/CMakeLists.txt b/tests/src/Interop/CMakeLists.txt
index 66124deb93..b4dec5750d 100644
--- a/tests/src/Interop/CMakeLists.txt
+++ b/tests/src/Interop/CMakeLists.txt
@@ -82,6 +82,7 @@ if(WIN32)
     add_subdirectory(COM/NativeServer)
     add_subdirectory(COM/NativeClients/Primitives)
     add_subdirectory(COM/NativeClients/Licensing)
+    add_subdirectory(COM/NativeClients/DefaultInterfaces)
     add_subdirectory(IJW/FakeMscoree)
 
     # IJW isn't supported on ARM64
diff --git a/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.il b/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.il
new file mode 100644
index 0000000000..3e4180c7b7
--- /dev/null
+++ b/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.il
@@ -0,0 +1,121 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+.assembly extern System.Runtime { }
+.assembly extern System.Runtime.InteropServices { }
+
+.assembly NETServer.DefaultInterfaces { }
+
+// Interface used for defining a method on an interface
+.class interface public abstract auto ansi Server.Contract.IDefaultInterfaceTesting
+{
+    .custom instance void [System.Runtime]System.Runtime.InteropServices.ComVisibleAttribute::.ctor(bool) =
+            ( 01 00 01 00 00 )
+    // GUID: FB6DF997-4CEF-4DF7-ADBD-E7FA395A7E0C
+    .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.GuidAttribute::.ctor(string) =
+            ( 01 00 24 46 42 36 44 46 39 39 37 2D 34 43 45 46
+              2D 34 44 46 37 2D 41 44 42 44 2D 45 37 46 41 33
+              39 35 41 37 45 30 43 00 00 )
+    .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.InterfaceTypeAttribute::.ctor(valuetype [System.Runtime.InteropServices]System.Runtime.InteropServices.ComInterfaceType) =
+            ( 01 00 01 00 00 00 00 00 )
+
+    .method public virtual
+        instance int32 DefOnInterfaceRet2() cil managed
+    {
+        // Default interface implementation
+        ldc.i4 2
+        ret
+    }
+
+    .method public hidebysig
+        instance void DefOnInterfaceNonVirtual() cil managed
+    {
+        // Non-virtual interface instance method
+        ret
+    }
+
+    .method public hidebysig
+        static void DefOnInterfaceStatic() cil managed
+    {
+        // Static interface method
+        ret
+    }
+
+    .method public abstract virtual
+        instance int32 DefOnClassRet3() cil managed
+    {
+        // Simple interface method
+    }
+
+    .method public hidebysig
+        static void DefOnInterfaceStatic2() cil managed
+    {
+        // Static interface method
+        ret
+    }
+
+    .method public hidebysig
+        instance void DefOnInterfaceNonVirtual2() cil managed
+    {
+        // Non-virtual interface instance method
+        ret
+    }
+
+    .method public abstract virtual
+        instance int32 DefOnInterface2Ret5() cil managed
+    {
+        // Simple interface method
+    }
+}
+
+// Interface defintion for overriding another interface's implementation
+.class interface private abstract auto ansi Server.Contract.IDefaultInterfaceTesting2
+       implements Server.Contract.IDefaultInterfaceTesting
+{
+    .custom instance void [System.Runtime]System.Runtime.InteropServices.ComVisibleAttribute::.ctor(bool) =
+            ( 01 00 01 00 00 )
+    // GUID: 9B3CE792-F063-427D-B48E-4354094BF7A0
+    .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.GuidAttribute::.ctor(string) =
+            ( 01 00 24 39 42 33 43 45 37 39 32 2D 46 30 36 33
+              2D 34 32 37 44 2D 42 34 38 45 2D 34 33 35 34 30
+              39 34 42 46 37 41 30 00 00 )
+    .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.InterfaceTypeAttribute::.ctor(valuetype [System.Runtime.InteropServices]System.Runtime.InteropServices.ComInterfaceType) =
+            ( 01 00 01 00 00 00 00 00 )
+
+    .method public virtual final
+        instance int32 DefOnInterface2Ret5() cil managed
+    {
+        .override Server.Contract.IDefaultInterfaceTesting::DefOnInterface2Ret5
+        ldc.i4 5
+        ret
+    }
+}
+
+// COM server consuming interfaces with default methods
+.class public auto ansi beforefieldinit DefaultInterfaceTesting
+       extends [System.Runtime]System.Object
+       implements Server.Contract.IDefaultInterfaceTesting2
+{  
+    .custom instance void [System.Runtime]System.Runtime.InteropServices.ComVisibleAttribute::.ctor(bool) = ( 01 00 01 00 00 )
+    // GUID: FAEF42AE-C1A4-419F-A912-B768AC2679EA
+    .custom instance void [System.Runtime.InteropServices]System.Runtime.InteropServices.GuidAttribute::.ctor(string) =
+            ( 01 00 24 46 41 45 46 34 32 41 45 2D 43 31 41 34
+              2D 34 31 39 46 2D 41 39 31 32 2D 42 37 36 38 41
+              43 32 36 37 39 45 41 00 00 )
+
+    .method public hidebysig specialname rtspecialname 
+            instance void .ctor() cil managed
+    {
+        ldarg.0
+        call instance void [System.Runtime]System.Object::.ctor()
+        ret
+    }
+
+    .method public hidebysig newslot virtual final 
+          instance int32  DefOnClassRet3() cil managed
+    {
+        ldc.i4 3
+        ret
+    }
+}
diff --git a/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.ilproj b/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.ilproj
new file mode 100644
index 0000000000..e68c1f64fb
--- /dev/null
+++ b/tests/src/Interop/COM/NETServer/NETServer.DefaultInterfaces.ilproj
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+  <PropertyGroup>
+    <AssemblyName>$(MSBuildProjectName)</AssemblyName>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <OutputType>library</OutputType>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="NETServer.DefaultInterfaces.il" />
+  </ItemGroup>
+
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+</Project>
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj b/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj
new file mode 100644
index 0000000000..040ec132bf
--- /dev/null
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces.csproj
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), Interop.settings.targets))\Interop.settings.targets" />
+  <PropertyGroup>
+    <IgnoreCoreCLRTestLibraryDependency>true</IgnoreCoreCLRTestLibraryDependency>
+    <CLRTestScriptLocalCoreShim>true</CLRTestScriptLocalCoreShim>
+
+    <TestUnsupportedOutsideWindows>true</TestUnsupportedOutsideWindows>
+    <DisableProjectBuild Condition="'$(TargetsUnix)' == 'true'">true</DisableProjectBuild>
+    <DefineConstants>BLOCK_WINDOWS_NANO</DefineConstants>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(InteropCommonDir)ExeLauncherProgram.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="DefaultInterfaces/CMakeLists.txt" />
+    <ProjectReference Include="../NetServer/NetServer.DefaultInterfaces.ilproj" />
+    <ProjectReference Include="../../../Common/hostpolicymock/CMakeLists.txt" />
+    <ProjectReference Include="../../../Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+</Project>
\ No newline at end of file
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces/App.manifest b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/App.manifest
new file mode 100644
index 0000000000..43e14712a2
--- /dev/null
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/App.manifest
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+  <assemblyIdentity
+    type="win32"
+    name="COMClientDefaultInterfaces"
+    version="1.0.0.0"/>
+
+  <dependency>
+    <dependentAssembly>
+      <!-- RegFree COM - CoreCLR Shim -->
+      <assemblyIdentity
+        type="win32"
+        name="CoreShim.X"
+        version="1.0.0.0"/>
+    </dependentAssembly>
+  </dependency>
+</assembly>
\ No newline at end of file
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CMakeLists.txt b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CMakeLists.txt
new file mode 100644
index 0000000000..e1448218f0
--- /dev/null
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CMakeLists.txt
@@ -0,0 +1,19 @@
+cmake_minimum_required (VERSION 2.6)
+
+project (COMClientDefaultInterfaces)
+include_directories( ${INC_PLATFORM_DIR} )
+include_directories( "../../ServerContracts" )
+include_directories( "../../NativeServer" )
+set(SOURCES
+    DefaultInterfacesTests.cpp
+    App.manifest)
+
+# add the executable
+add_executable (COMClientDefaultInterfaces ${SOURCES})
+target_link_libraries(COMClientDefaultInterfaces ${LINK_LIBRARIES_ADDITIONAL})
+
+# Copy CoreShim manifest to project output
+file(GENERATE OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>/CoreShim.X.manifest INPUT ${CMAKE_CURRENT_SOURCE_DIR}/CoreShim.X.manifest)
+
+# add the install targets
+install (TARGETS COMClientDefaultInterfaces DESTINATION bin)
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CoreShim.X.manifest b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CoreShim.X.manifest
new file mode 100644
index 0000000000..ef07fb0354
--- /dev/null
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/CoreShim.X.manifest
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+
+<assemblyIdentity
+  type="win32"
+  name="CoreShim.X"
+  version="1.0.0.0" />
+
+<file name="CoreShim.dll">
+  <!-- DefaultInterfaceTesting -->
+  <comClass
+    clsid="{FAEF42AE-C1A4-419F-A912-B768AC2679EA}"
+    threadingModel="Both" />
+</file>
+
+</assembly>
diff --git a/tests/src/Interop/COM/NativeClients/DefaultInterfaces/DefaultInterfacesTests.cpp b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/DefaultInterfacesTests.cpp
new file mode 100644
index 0000000000..9d87215049
--- /dev/null
+++ b/tests/src/Interop/COM/NativeClients/DefaultInterfaces/DefaultInterfacesTests.cpp
@@ -0,0 +1,83 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include <xplatform.h>
+#include <cassert>
+#include <Server.Contracts.h>
+
+// COM headers
+#include <objbase.h>
+#include <combaseapi.h>
+
+#define COM_CLIENT
+#include <Servers.h>
+
+#define THROW_IF_FAILED(exp) { hr = exp; if (FAILED(hr)) { ::printf("FAILURE: 0x%08x = %s\n", hr, #exp); throw hr; } }
+#define THROW_FAIL_IF_FALSE(exp) { if (!(exp)) { ::printf("FALSE: %s\n", #exp); throw E_FAIL; } }
+
+template<COINIT TM>
+struct ComInit
+{
+    const HRESULT Result;
+
+    ComInit()
+        : Result{ ::CoInitializeEx(nullptr, TM) }
+    { }
+
+    ~ComInit()
+    {
+        if (SUCCEEDED(Result))
+            ::CoUninitialize();
+    }
+};
+
+using ComMTA = ComInit<COINIT_MULTITHREADED>;
+
+void CallDefaultInterface();
+
+int __cdecl main()
+{
+    ComMTA init;
+    if (FAILED(init.Result))
+        return -1;
+
+    try
+    {
+        CoreShimComActivation csact{ W("NetServer.DefaultInterfaces"), W("DefaultInterfaceTesting") };
+
+        CallDefaultInterface();
+    }
+    catch (HRESULT hr)
+    {
+        ::printf("Test Failure: 0x%08x\n", hr);
+        return 101;
+    }
+
+    return 100;
+}
+
+void CallDefaultInterface()
+{
+    ::printf("Call functions on Default Interface...\n");
+
+    HRESULT hr;
+
+    ComSmartPtr<IDefaultInterfaceTesting> defInterface;
+    THROW_IF_FAILED(::CoCreateInstance(CLSID_DefaultInterfaceTesting, nullptr, CLSCTX_INPROC, IID_IDefaultInterfaceTesting, (void**)&defInterface));
+
+    int i;
+
+    THROW_IF_FAILED(defInterface->DefOnInterfaceRet2(&i));
+    THROW_FAIL_IF_FALSE(i == 2);
+
+    THROW_IF_FAILED(defInterface->DefOnClassRet3(&i));
+    THROW_FAIL_IF_FALSE(i == 3);
+
+    //
+    // Overridden default interface defintions do not work
+    // https://github.com/dotnet/coreclr/issues/15683
+    //
+    //THROW_IF_FAILED(defInterface->DefOnInterface2Ret5(&i));
+    //THROW_FAIL_IF_FALSE(i == 5);
+}
diff --git a/tests/src/Interop/COM/NativeClients/Primitives/ClientTests.h b/tests/src/Interop/COM/NativeClients/Primitives/ClientTests.h
index 00370f2ce2..84733b4c3e 100644
--- a/tests/src/Interop/COM/NativeClients/Primitives/ClientTests.h
+++ b/tests/src/Interop/COM/NativeClients/Primitives/ClientTests.h
@@ -12,58 +12,6 @@
 #define THROW_IF_FAILED(exp) { hr = exp; if (FAILED(hr)) { ::printf("FAILURE: 0x%08x = %s\n", hr, #exp); throw hr; } }
 #define THROW_FAIL_IF_FALSE(exp) { if (!(exp)) { ::printf("FALSE: %s\n", #exp); throw E_FAIL; } }
 
-template<typename T>
-struct ComSmartPtr
-{
-    ComSmartPtr()
-        : p{}
-    { }
-
-    ComSmartPtr(_In_ const ComSmartPtr &) = delete;
-    ComSmartPtr(_Inout_ ComSmartPtr &&) = delete;
-
-    ComSmartPtr& operator=(_In_ const ComSmartPtr &) = delete;
-    ComSmartPtr& operator=(_Inout_ ComSmartPtr &&) = delete;
-
-    ~ComSmartPtr()
-    {
-        if (p != nullptr)
-            p->Release();
-    }
-
-    operator T*()
-    {
-        return p;
-    }
-
-    T** operator&()
-    {
-        return &p;
-    }
-
-    T* operator->()
-    {
-        return p;
-    }
-
-    void Attach(_In_opt_ T *t)
-    {
-        if (p != nullptr)
-            p->Release();
-
-        p = t;
-    }
-
-    T *Detach()
-    {
-        T *tmp = p;
-        p = nullptr;
-        return tmp;
-    }
-
-    T *p;
-};
-
 void Run_NumericTests();
 void Run_ArrayTests();
 void Run_StringTests();
diff --git a/tests/src/Interop/COM/NativeServer/Servers.h b/tests/src/Interop/COM/NativeServer/Servers.h
index 61f16ca13a..2ff3f88ce0 100644
--- a/tests/src/Interop/COM/NativeServer/Servers.h
+++ b/tests/src/Interop/COM/NativeServer/Servers.h
@@ -19,6 +19,7 @@ class DECLSPEC_UUID("4DBD9B61-E372-499F-84DE-EFC70AA8A009") EventTesting;
 class DECLSPEC_UUID("4CEFE36D-F377-4B6E-8C34-819A8BB9CB04") AggregationTesting;
 class DECLSPEC_UUID("C222F472-DA5A-4FC6-9321-92F4F7053A65") ColorTesting;
 class DECLSPEC_UUID("66DB7882-E2B0-471D-92C7-B2B52A0EA535") LicenseTesting;
+class DECLSPEC_UUID("FAEF42AE-C1A4-419F-A912-B768AC2679EA") DefaultInterfaceTesting;
 
 #define CLSID_NumericTesting __uuidof(NumericTesting)
 #define CLSID_ArrayTesting __uuidof(ArrayTesting)
@@ -29,6 +30,7 @@ class DECLSPEC_UUID("66DB7882-E2B0-471D-92C7-B2B52A0EA535") LicenseTesting;
 #define CLSID_AggregationTesting __uuidof(AggregationTesting)
 #define CLSID_ColorTesting __uuidof(ColorTesting)
 #define CLSID_LicenseTesting __uuidof(LicenseTesting)
+#define CLSID_DefaultInterfaceTesting __uuidof(DefaultInterfaceTesting)
 
 #define IID_INumericTesting __uuidof(INumericTesting)
 #define IID_IArrayTesting __uuidof(IArrayTesting)
@@ -40,6 +42,8 @@ class DECLSPEC_UUID("66DB7882-E2B0-471D-92C7-B2B52A0EA535") LicenseTesting;
 #define IID_IAggregationTesting __uuidof(IAggregationTesting)
 #define IID_IColorTesting __uuidof(IColorTesting)
 #define IID_ILicenseTesting __uuidof(ILicenseTesting)
+#define IID_IDefaultInterfaceTesting __uuidof(IDefaultInterfaceTesting)
+#define IID_IDefaultInterfaceTesting2 __uuidof(IDefaultInterfaceTesting2)
 
 // Class used for COM activation when using CoreShim
 struct CoreShimComActivation
@@ -64,6 +68,58 @@ private:
     }
 };
 
+template<typename T>
+struct ComSmartPtr
+{
+    ComSmartPtr()
+        : p{}
+    { }
+
+    ComSmartPtr(_In_ const ComSmartPtr &) = delete;
+    ComSmartPtr(_Inout_ ComSmartPtr &&) = delete;
+
+    ComSmartPtr& operator=(_In_ const ComSmartPtr &) = delete;
+    ComSmartPtr& operator=(_Inout_ ComSmartPtr &&) = delete;
+
+    ~ComSmartPtr()
+    {
+        if (p != nullptr)
+            p->Release();
+    }
+
+    operator T*()
+    {
+        return p;
+    }
+
+    T** operator&()
+    {
+        return &p;
+    }
+
+    T* operator->()
+    {
+        return p;
+    }
+
+    void Attach(_In_opt_ T *t)
+    {
+        if (p != nullptr)
+            p->Release();
+
+        p = t;
+    }
+
+    T *Detach()
+    {
+        T *tmp = p;
+        p = nullptr;
+        return tmp;
+    }
+
+    T *p;
+};
+
 #ifndef COM_CLIENT
     #include <ComHelpers.h>
 
diff --git a/tests/src/Interop/COM/ServerContracts/NativeServers.cs b/tests/src/Interop/COM/ServerContracts/NativeServers.cs
index 0a14e4fdca..724f7e2bcc 100644
--- a/tests/src/Interop/COM/ServerContracts/NativeServers.cs
+++ b/tests/src/Interop/COM/ServerContracts/NativeServers.cs
@@ -161,6 +161,28 @@ namespace Server.Contract.Servers
     internal class LicenseTestingClass
     {
     }
+
+/** Implement when main line C# compiler supports default interfaces.
+
+    /// <summary>
+    /// Managed definition of CoClass
+    /// </summary>
+    [ComImport]
+    [CoClass(typeof(DefaultInterfaceTestingClass))]
+    [Guid("FB6DF997-4CEF-4DF7-ADBD-E7FA395A7E0C")]
+    internal interface DefaultInterfaceTesting : Server.Contract.IDefaultInterfaceTesting
+    {
+    }
+
+    /// <summary>
+    /// Managed activation for CoClass
+    /// </summary>
+    [ComImport]
+    [Guid(Server.Contract.Guids.DefaultInterfaceTesting)]
+    internal class DefaultInterfaceTestingClass
+    {
+    }
+*/
 }
 
 #pragma warning restore 618 // Must test deprecated features
diff --git a/tests/src/Interop/COM/ServerContracts/Server.Contracts.h b/tests/src/Interop/COM/ServerContracts/Server.Contracts.h
index 1db14e4676..b985cd3547 100644
--- a/tests/src/Interop/COM/ServerContracts/Server.Contracts.h
+++ b/tests/src/Interop/COM/ServerContracts/Server.Contracts.h
@@ -5,47 +5,6 @@
 
 #include <comdef.h>
 
-//
-// Forward references and typedefs
-//
-
-struct __declspec(uuid("05655a94-a915-4926-815d-a9ea648baad9"))
-/* interface */ INumericTesting;
-struct __declspec(uuid("7731cb31-e063-4cc8-bcd2-d151d6bc8f43"))
-/* interface */ IArrayTesting;
-struct __declspec(uuid("7044c5c0-c6c6-4713-9294-b4a4e86d58cc"))
-/* interface */ IStringTesting;
-struct __declspec(uuid("592386a5-6837-444d-9de3-250815d18556"))
-/* interface */ IErrorMarshalTesting;
-struct __declspec(uuid("a5e04c1c-474e-46d2-bbc0-769d04e12b54"))
-/* interface */ IDispatchTesting;
-struct __declspec(uuid("83AFF8E4-C46A-45DB-9D91-2ADB5164545E"))
-/* interface */ IEventTesting;
-struct __declspec(uuid("98cc27f0-d521-4f79-8b63-e980e3a92974"))
-/* interface */ IAggregationTesting;
-struct __declspec(uuid("E6D72BA7-0936-4396-8A69-3B76DA1108DA"))
-/* interface */ IColorTesting;
-struct __declspec(uuid("6C9E230E-411F-4219-ABFD-E71F2B84FD50"))
-/* interface */ ILicenseTesting;
-
-//
-// Smart pointer typedef declarations
-//
-
-_COM_SMARTPTR_TYPEDEF(INumericTesting, __uuidof(INumericTesting));
-_COM_SMARTPTR_TYPEDEF(IArrayTesting, __uuidof(IArrayTesting));
-_COM_SMARTPTR_TYPEDEF(IStringTesting, __uuidof(IStringTesting));
-_COM_SMARTPTR_TYPEDEF(IErrorMarshalTesting, __uuidof(IErrorMarshalTesting));
-_COM_SMARTPTR_TYPEDEF(IDispatchTesting, __uuidof(IDispatchTesting));
-_COM_SMARTPTR_TYPEDEF(IEventTesting, __uuidof(IEventTesting));
-_COM_SMARTPTR_TYPEDEF(IAggregationTesting, __uuidof(IAggregationTesting));
-_COM_SMARTPTR_TYPEDEF(IColorTesting, __uuidof(IColorTesting));
-_COM_SMARTPTR_TYPEDEF(ILicenseTesting, __uuidof(ILicenseTesting));
-
-//
-// Type library items
-//
-
 struct __declspec(uuid("05655a94-a915-4926-815d-a9ea648baad9"))
 INumericTesting : IUnknown
 {
@@ -499,4 +458,20 @@ ILicenseTesting : IUnknown
     virtual HRESULT STDMETHODCALLTYPE SetNextLicense(_In_z_ LPCOLESTR lic) = 0;
 };
 
+struct __declspec(uuid("FB6DF997-4CEF-4DF7-ADBD-E7FA395A7E0C"))
+IDefaultInterfaceTesting : IUnknown
+{
+    virtual HRESULT STDMETHODCALLTYPE DefOnInterfaceRet2(_Out_ int *p) = 0;
+
+    virtual HRESULT STDMETHODCALLTYPE DefOnClassRet3(_Out_ int *p) = 0;
+
+    virtual HRESULT STDMETHODCALLTYPE DefOnInterface2Ret5(_Out_ int *p) = 0;
+};
+
+struct __declspec(uuid("9B3CE792-F063-427D-B48E-4354094BF7A0"))
+IDefaultInterfaceTesting2 : IDefaultInterfaceTesting
+{
+
+};
+
 #pragma pack(pop)
diff --git a/tests/src/Interop/COM/ServerContracts/ServerGuids.cs b/tests/src/Interop/COM/ServerContracts/ServerGuids.cs
index 2ebeed8840..98ed0aed85 100644
--- a/tests/src/Interop/COM/ServerContracts/ServerGuids.cs
+++ b/tests/src/Interop/COM/ServerContracts/ServerGuids.cs
@@ -18,5 +18,6 @@ namespace Server.Contract
         public const string AggregationTesting = "4CEFE36D-F377-4B6E-8C34-819A8BB9CB04";
         public const string ColorTesting = "C222F472-DA5A-4FC6-9321-92F4F7053A65";
         public const string LicenseTesting = "66DB7882-E2B0-471D-92C7-B2B52A0EA535";
+        public const string DefaultInterfaceTesting = "FAEF42AE-C1A4-419F-A912-B768AC2679EA";
     }
 }