dotnet · MichalStrehovsky · Dec 5, 2017 · Dec 4, 2017 · Dec 5, 2017
diff --git a/clr.defines.targets b/clr.defines.targets
@@ -1,4 +1,10 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+    <!-- Features we're currently flighting, but don't intend to ship in officially supported releases -->
+    <PropertyGroup Condition="'$(IsPrerelease)' == 'true'">
+        <FeatureDefaultInterfaces>true</FeatureDefaultInterfaces>
+    </PropertyGroup>
+
     <PropertyGroup>
         <DefineConstants Condition="'$(FeatureAppX)' == 'true'">$(DefineConstants);FEATURE_APPX</DefineConstants>
         <DefineConstants Condition="'$(FeatureArrayStubAsIL)' == 'true'">$(DefineConstants);FEATURE_ARRAYSTUB_AS_IL</DefineConstants>
@@ -17,6 +23,7 @@
         <DefineConstants Condition="'$(FeatureXplatEventSource)' == 'true'">$(DefineConstants);FEATURE_EVENTSOURCE_XPLAT</DefineConstants>
         <DefineConstants Condition="'$(FeatureUseLcid)' == 'true'">$(DefineConstants);FEATURE_USE_LCID</DefineConstants>
         <DefineConstants Condition="'$(FeatureWin32Registry)' == 'true'">$(DefineConstants);FEATURE_WIN32_REGISTRY</DefineConstants>
+        <DefineConstants Condition="'$(FeatureDefaultInterfaces)' == 'true'">$(DefineConstants);FEATURE_DEFAULT_INTERFACES</DefineConstants>
 
         <DefineConstants Condition="'$(ProfilingSupportedBuild)' == 'true'">$(DefineConstants);PROFILING_SUPPORTED</DefineConstants>
 

diff --git a/clrdefinitions.cmake b/clrdefinitions.cmake
@@ -1,5 +1,14 @@
 include(clrfeatures.cmake)
 
+# If set, indicates that this is not an officially supported release
+# Keep in sync with IsPrerelease in dir.props
+set(PRERELEASE 1)
+
+# Features we're currently flighting, but don't intend to ship in officially supported releases
+if (PRERELEASE)
+  add_definitions(-DFEATURE_DEFAULT_INTERFACES=1)  
+endif (PRERELEASE)
+
 if (CLR_CMAKE_TARGET_ARCH_AMD64)
   if (CLR_CMAKE_PLATFORM_UNIX)
     add_definitions(-DDBG_TARGET_AMD64_UNIX)

diff --git a/dir.props b/dir.props
@@ -140,6 +140,11 @@
     <PackageThirdPartyNoticesFile>$(ProjectDir)THIRD-PARTY-NOTICES.TXT</PackageThirdPartyNoticesFile>
     <SyncInfoDirectory>$(BaseIntermediateOutputPath)</SyncInfoDirectory>
 
+    <!-- If true, indicates that this is not an officially supported release -->
+    <!-- It is important to flip this to false in official release branches -->
+    <!-- Keep it in sync with PRERELEASE in clrdefinitions.cmake -->
+    <IsPrerelease>true</IsPrerelease>
+
     <!-- This should be kept in sync with package details in src/.nuget/init/project.json -->
     <RuntimeIdGraphDefinitionVersion>1.0.2-beta-24224-02</RuntimeIdGraphDefinitionVersion>
     <RuntimeIdGraphDefinitionFile>$(PackagesDir)/microsoft.netcore.platforms/$(RuntimeIdGraphDefinitionVersion)/runtime.json</RuntimeIdGraphDefinitionFile>

diff --git a/src/inc/clrconfigvalues.h b/src/inc/clrconfigvalues.h
@@ -874,7 +874,6 @@ RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TieredCompilation, W("EXPERIMENTAL_TieredCo
 // TypeLoader
 // 
 CONFIG_DWORD_INFO(INTERNAL_TypeLoader_InjectInterfaceDuplicates, W("INTERNAL_TypeLoader_InjectInterfaceDuplicates"), 0, "Injects duplicates in interface map for all types.")
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TypeLoader_DefaultInterfaces, W("UNSUPPORTED_TypeLoader_DefaultInterfaces"), 0, "Enables support for default interfaces.")
 
 // 
 // Virtual call stubs

diff --git a/src/mscorlib/shared/System/Runtime/CompilerServices/RuntimeFeature.cs b/src/mscorlib/shared/System/Runtime/CompilerServices/RuntimeFeature.cs
@@ -11,9 +11,12 @@ public static class RuntimeFeature
         /// </summary>
         public const string PortablePdb = nameof(PortablePdb);
 
+#if FEATURE_DEFAULT_INTERFACES
+        /// <summary>
         /// Indicates that this version of runtime supports default interface method implementations.
         /// </summary>
         public const string DefaultImplementationsOfInterfaces = nameof(DefaultImplementationsOfInterfaces);
+#endif
 
         /// <summary>
         /// Checks whether a certain feature is supported by the Runtime.
@@ -23,7 +26,9 @@ public static bool IsSupported(string feature)
             switch (feature)
             {
                 case PortablePdb:
+#if FEATURE_DEFAULT_INTERFACES
                 case DefaultImplementationsOfInterfaces:
+#endif
                     return true;
             }
 

diff --git a/src/vm/classcompat.cpp b/src/vm/classcompat.cpp
@@ -2612,25 +2612,27 @@ VOID    MethodTableBuilder::EnumerateClassMethods()
             }
         }
 
+#ifndef FEATURE_DEFAULT_INTERFACES
         // Some interface checks.
         if (fIsClassInterface)
         {
             if (IsMdVirtual(dwMemberAttrs))
             {
-                if (!IsMdAbstract(dwMemberAttrs) && (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_TypeLoader_DefaultInterfaces) == 0))
+                if (!IsMdAbstract(dwMemberAttrs))
                 {
                     BuildMethodTableThrowException(BFA_VIRTUAL_NONAB_INT_METHOD);
                 }
             } 
             else
             {
                 // Instance field/method
-                if (!IsMdStatic(dwMemberAttrs) && (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_TypeLoader_DefaultInterfaces) == 0))
+                if (!IsMdStatic(dwMemberAttrs))
                 {
                     BuildMethodTableThrowException(BFA_NONVIRT_INST_INT_METHOD);
                 }
             }
         }
+#endif
 
         // No synchronized methods in ValueTypes
         if(fIsClassValueType && IsMiSynchronized(dwImplFlags))

diff --git a/src/vm/methodtablebuilder.cpp b/src/vm/methodtablebuilder.cpp
@@ -2900,25 +2900,27 @@ MethodTableBuilder::EnumerateClassMethods()
             }
         }
 
+#ifndef FEATURE_DEFAULT_INTERFACES
         // Some interface checks.
         if (fIsClassInterface)
         {
             if (IsMdVirtual(dwMemberAttrs))
             {
-                if (!IsMdAbstract(dwMemberAttrs) && (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_TypeLoader_DefaultInterfaces) == 0))
+                if (!IsMdAbstract(dwMemberAttrs))
                 {
                     BuildMethodTableThrowException(BFA_VIRTUAL_NONAB_INT_METHOD);
                 }
             }
             else
             {
                 // Instance field/method
-                if (!IsMdStatic(dwMemberAttrs) && (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_TypeLoader_DefaultInterfaces) == 0))
+                if (!IsMdStatic(dwMemberAttrs))
                 {
                     BuildMethodTableThrowException(BFA_NONVIRT_INST_INT_METHOD);
                 }
             }
         }
+#endif
 
         // No synchronized methods in ValueTypes
         if(fIsClassValueType && IsMiSynchronized(dwImplFlags))

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/constrainedcall/constrainedcall.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/constrainedcall/constrainedcall.ilproj
@@ -14,23 +14,7 @@
     <ReferenceLocalMscorlib>true</ReferenceLocalMscorlib>
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
-    <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
+    <CLRTestPriority>0</CLRTestPriority>    
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/diamondshape/diamondshape.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/diamondshape/diamondshape.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>    
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/genericmethods/genericmethods.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/genericmethods/genericmethods.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/methodimpl/methodimpl.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/methodimpl/methodimpl.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/sharedgenerics/sharedgenerics.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/sharedgenerics/sharedgenerics.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/simple/simple.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/simple/simple.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>  
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/Loader/classloader/DefaultInterfaceMethods/valuetypes/valuetypes.ilproj b/tests/src/Loader/classloader/DefaultInterfaceMethods/valuetypes/valuetypes.ilproj
@@ -15,22 +15,6 @@
     <OutputType>Exe</OutputType>
     <CLRTestKind>BuildAndRun</CLRTestKind>
     <CLRTestPriority>0</CLRTestPriority>
-    <!-- Use ILAsm that we just built for the new fixes required in default interface methods -->
-    <UseCustomILAsm>True</UseCustomILAsm>    
-
-    <CLRTestBatchPreCommands>
-<![CDATA[
-      $(CLRTestBatchPreCommands)
-set COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </CLRTestBatchPreCommands>
-    <BashCLRTestPreCommands>
-<![CDATA[
-      $(BashCLRTestPreCommands)
-export COMPlus_UNSUPPORTED_TypeLoader_DefaultInterfaces=1
-    ]]>
-    </BashCLRTestPreCommands>
-
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/tests/src/baseservices/compilerservices/RuntimeFeature/DefaultImplementationsOfInterfaces.il b/tests/src/baseservices/compilerservices/RuntimeFeature/DefaultImplementationsOfInterfaces.il
@@ -0,0 +1,73 @@
+// 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.
+
+//
+// Verifies that RuntimeFeature::IsSupported("DefaultImplementationsOfInterfaces") matches reality.
+// This needs to succeed no matter whether default interfaces are supported.
+//
+
+.assembly extern System.Runtime{}
+.assembly DefaultImplementationsOfInterfaces{}
+
+.class interface private abstract auto ansi DefaultInterface
+{
+  .method public hidebysig newslot virtual 
+          instance void  Method() cil managed
+  {
+    .maxstack  8
+    ret
+  }
+}
+
+.method private hidebysig static void TryLoadDefaultInterface() cil managed noinlining
+{
+    .maxstack  8
+    ldtoken    DefaultInterface
+    call       class [System.Runtime]System.Type [System.Runtime]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
+    callvirt   instance string [System.Runtime]System.Object::ToString()
+    pop
+    ret
+}
+
+.method private hidebysig static bool  SupportsDefaultInterfaces() cil managed
+{
+    .maxstack  1
+    .try
+    {
+      call       void TryLoadDefaultInterface()
+      leave.s    Supports
+
+    }
+    catch [System.Runtime]System.TypeLoadException 
+    {
+      pop
+      leave.s    DoesNotSupport
+
+    }
+  Supports:
+    ldc.i4.1
+    ret
+
+  DoesNotSupport:
+    ldc.i4.0
+    ret
+  }
+
+.method private hidebysig static int32 
+        Main() cil managed
+{
+    .entrypoint
+    .maxstack  2
+    ldstr      "DefaultImplementationsOfInterfaces"
+    call       bool [System.Runtime]System.Runtime.CompilerServices.RuntimeFeature::IsSupported(string)
+    call       bool SupportsDefaultInterfaces()
+    beq        Good
+
+    ldc.i4.m1
+    ret
+
+  Good:
+    ldc.i4     100
+    ret
+}