Use reflection or a compile-time only shim assembly to reference unexposed corelib types.

docs/workflow/testing/coreclr/test-configuration.md

@@ -52,8 +52,6 @@ Therefore the managed portion of each test **must not contain**:
 * Exclude test from JIT stress runs runs by adding the following to the csproj:
     * `<JitOptimizationSensitive>true</JitOptimizationSensitive>`
 * Add NuGet references by updating the following [test project](https://github.com/dotnet/runtime/blob/main/src/tests/Common/test_dependencies/test_dependencies.csproj).
-* Get access to System.Private.CoreLib types and methods that are not exposed via public surface by adding the following to the csproj:
-    * `<ReferenceSystemPrivateCoreLib>true</ReferenceSystemPrivateCoreLib>`
 * Any System.Private.CoreLib types and methods used by tests must be available for building on all platforms.
 This means there must be enough implementation for the C# compiler to find the referenced types and methods. Unsupported target platforms
 should simply `throw new PlatformNotSupportedException()` in its dummy method implementations.

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComActivationContextInternal.cs

@@ -25,7 +25,7 @@ public unsafe struct ComActivationContextInternal
     //
 
     [StructLayout(LayoutKind.Sequential)]
-    public partial struct ComActivationContext
+    internal partial struct ComActivationContext
     {
         public Guid ClassId;
         public Guid InterfaceId;
@@ -38,7 +38,7 @@ public partial struct ComActivationContext
     [ComVisible(false)]
     [Guid("00000001-0000-0000-C000-000000000046")]
     [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
-    public interface IClassFactory
+    internal interface IClassFactory
     {
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
         void CreateInstance(

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComActivator.PlatformNotSupported.cs

@@ -12,35 +12,24 @@ public static class ComActivator
         /// Internal entry point for unmanaged COM activation API from native code
         /// </summary>
         /// <param name="pCxtInt">Pointer to a <see cref="ComActivationContextInternal"/> instance</param>
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int GetClassFactoryForTypeInternal(ComActivationContextInternal* pCxtInt)
+        private static unsafe int GetClassFactoryForTypeInternal(ComActivationContextInternal* pCxtInt)
             => throw new PlatformNotSupportedException();
 
         /// <summary>
         /// Internal entry point for registering a managed COM server API from native code
         /// </summary>
         /// <param name="pCxtInt">Pointer to a <see cref="ComActivationContextInternal"/> instance</param>
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int RegisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
+        private static unsafe int RegisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
             => throw new PlatformNotSupportedException();
 
         /// <summary>
         /// Internal entry point for unregistering a managed COM server API from native code
         /// </summary>
         /// <param name="pCxtInt">Pointer to a <see cref="ComActivationContextInternal"/> instance</param>
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int UnregisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
-            => throw new PlatformNotSupportedException();
-
-        // Exists here to allow tests to build on any platform.
-        public static object GetClassFactoryForType(ComActivationContext cxt)
-            => throw new PlatformNotSupportedException();
-
-        // Exists here to allow tests to build on any platform.
-        public static void ClassRegistrationScenarioForType(ComActivationContext cxt, bool register)
+        private static unsafe int UnregisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
             => throw new PlatformNotSupportedException();
     }
 }

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComActivator.cs

@@ -57,10 +57,9 @@ void CreateInstanceLic(
             out IntPtr ppvObject);
     }
 
-    public partial struct ComActivationContext
+    internal partial struct ComActivationContext
     {
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        [CLSCompliant(false)]
         public static unsafe ComActivationContext Create(ref ComActivationContextInternal cxtInt)
         {
             if (!Marshal.IsBuiltInComSupported)
@@ -91,7 +90,7 @@ public static class ComActivator
         /// </summary>
         /// <param name="cxt">Reference to a <see cref="ComActivationContext"/> instance</param>
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        public static object GetClassFactoryForType(ComActivationContext cxt)
+        private static object GetClassFactoryForType(ComActivationContext cxt)
         {
             if (!Marshal.IsBuiltInComSupported)
             {
@@ -125,7 +124,7 @@ public static object GetClassFactoryForType(ComActivationContext cxt)
         /// <param name="cxt">Reference to a <see cref="ComActivationContext"/> instance</param>
         /// <param name="register">true if called for register or false to indicate unregister</param>
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        public static void ClassRegistrationScenarioForType(ComActivationContext cxt, bool register)
+        private static void ClassRegistrationScenarioForType(ComActivationContext cxt, bool register)
         {
             if (!Marshal.IsBuiltInComSupported)
             {
@@ -219,9 +218,8 @@ public static void ClassRegistrationScenarioForType(ComActivationContext cxt, bo
         /// </summary>
         /// <param name="pCxtInt">Pointer to a <see cref="ComActivationContextInternal"/> instance</param>
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int GetClassFactoryForTypeInternal(ComActivationContextInternal* pCxtInt)
+        private static unsafe int GetClassFactoryForTypeInternal(ComActivationContextInternal* pCxtInt)
         {
             if (!Marshal.IsBuiltInComSupported)
             {
@@ -262,9 +260,8 @@ public static unsafe int GetClassFactoryForTypeInternal(ComActivationContextInte
         /// </summary>
         /// <param name="pCxtInt">Pointer to a <see cref="ComActivationContextInternal"/> instance</param>
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int RegisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
+        private static unsafe int RegisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
         {
             if (!Marshal.IsBuiltInComSupported)
             {
@@ -308,9 +305,8 @@ public static unsafe int RegisterClassForTypeInternal(ComActivationContextIntern
         /// Internal entry point for unregistering a managed COM server API from native code
         /// </summary>
         [RequiresUnreferencedCode("Built-in COM support is not trim compatible", Url = "https://aka.ms/dotnet-illink/com")]
-        [CLSCompliant(false)]
         [UnmanagedCallersOnly]
-        public static unsafe int UnregisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
+        private static unsafe int UnregisterClassForTypeInternal(ComActivationContextInternal* pCxtInt)
         {
             if (!Marshal.IsBuiltInComSupported)
             {

src/tests/Common/XUnitWrapperGenerator/XUnitWrapperGenerator.props

@@ -6,7 +6,6 @@
     <CompilerVisibleProperty Include="TargetArchitecture" />
     <CompilerVisibleProperty Include="Priority" />
     <!-- Properties that influence test harness generation -->
-    <CompilerVisibleProperty Include="ReferenceSystemPrivateCoreLib" />
     <CompilerVisibleProperty Include="IsMergedTestRunnerAssembly" />
     <CompilerVisibleProperty Include="TestFilter" />
     <CompilerVisibleItemMetadata Include="AdditionalFiles" MetadataName="IsOutOfProcessTestAssembly" />

src/tests/Directory.Build.targets

@@ -80,7 +80,6 @@
     <_WillCLRTestProjectBuild Condition="'$(BuildAllProjects)' != 'true'">true</_WillCLRTestProjectBuild>
     <_WillCLRTestProjectBuild Condition="'$(BuildAllProjects)' == 'true' And '$(CLRTestPriority)' &lt;= '$(CLRTestPriorityToBuild)'">true</_WillCLRTestProjectBuild>
     <_WillCLRTestProjectBuild Condition="'$(CLRTestBuildAllTargets)' != 'allTargets' And '$(CLRTestTargetUnsupported)' == 'true'">false</_WillCLRTestProjectBuild>
-    <_WillCLRTestProjectBuild Condition="'$(ReferenceSystemPrivateCoreLib)' == 'true' and '$(RuntimeFlavor)' == 'mono'">false</_WillCLRTestProjectBuild>
     <_WillCLRTestProjectBuild Condition="'$(DisableProjectBuild)' == 'true'">false</_WillCLRTestProjectBuild>
   </PropertyGroup>
   <PropertyGroup>
@@ -95,8 +94,6 @@
   <!-- RunOnly projects have a special build for dependent projects -->
   <Import Project="$(MSBuildThisFileDirectory)Common\runonly.targets" Condition="'$(CLRTestKind)' == 'RunOnly'" />
 
-  <Import Project="$(MSBuildThisFileDirectory)Common\override.targets" />
-
   <!-- We enable auto-unification of assembly references after importing the common targets.  Binding redirects are not needed
        for coreclr since it auto-unifies, so the warnings we get without this setting are just noise -->
   <PropertyGroup>
@@ -225,12 +222,11 @@
           BeforeTargets="BeforeResolveReferences"
   >
    <MSBuild Projects="$(MSBuildProjectFullPath)"
-            Targets="GetLiveRefAssemblies"
-            Condition="'$(ReferenceSystemPrivateCoreLib)' != 'true'">
+            Targets="GetLiveRefAssemblies">
     <Output TaskParameter="TargetOutputs" ItemName="Reference" />
    </MSBuild>
 
-    <ItemGroup Condition="'$(ReferenceSystemPrivateCoreLib)' != 'true'">
+    <ItemGroup >
       <Reference Include="$(TargetingPackPath)/*.dll" >
         <Private>false</Private>
       </Reference>
@@ -255,10 +251,6 @@
     <ProjectAssetsFile>$(BaseOutputPath)\packages\Common\test_dependencies\test_dependencies\project.assets.json</ProjectAssetsFile>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(ReferenceSystemPrivateCoreLib)' == 'true' and '$(UsingMicrosoftNETSdk)' != 'true'">
-    <ProjectAssetsFile></ProjectAssetsFile>
-  </PropertyGroup>
-
   <PropertyGroup>
     <DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
   </PropertyGroup>

src/tests/Interop/COM/Activator/Activator.csproj

@@ -1,14 +1,15 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <!-- Internal.Runtime.InteropServices is CoreCLR-only -->
-    <ReferenceSystemPrivateCoreLib>true</ReferenceSystemPrivateCoreLib>
     <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
     <!-- The test fails casting from ClassFromA from the default ALC to type IGetTypeFromC from a custom ALC -->
     <UnloadabilityIncompatible>true</UnloadabilityIncompatible>
+    <DisableProjectBuild Condition="'$(RuntimeFlavor)' == 'Mono'">true</DisableProjectBuild>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Program.cs" />
+    <Compile Include="ComActivationContext.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\NETServer\NETServer.csproj" />

src/tests/Interop/COM/Activator/ActivatorBuiltInComDisabled.csproj

@@ -1,14 +1,15 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <!-- Internal.Runtime.InteropServices is CoreCLR-only -->
-    <ReferenceSystemPrivateCoreLib>true</ReferenceSystemPrivateCoreLib>
     <RequiresMockHostPolicy>true</RequiresMockHostPolicy>
     <!-- The test fails casting from ClassFromA from the default ALC to type IGetTypeFromC from a custom ALC -->
     <UnloadabilityIncompatible>true</UnloadabilityIncompatible>
+    <DisableProjectBuild Condition="'$(RuntimeFlavor)' == 'Mono'">true</DisableProjectBuild>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Program.cs" />
+    <Compile Include="ComActivationContext.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\NETServer\NETServer.csproj" />

src/tests/Interop/COM/Activator/ComActivationContext.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+namespace Activator
+{
+    [StructLayout(LayoutKind.Sequential)]
+    public partial struct ComActivationContext
+    {
+        public Guid ClassId;
+        public Guid InterfaceId;
+        public string AssemblyPath;
+        public string AssemblyName;
+        public string TypeName;
+    }
+}