Remove RequiresPreviewFeatures attribute on Lock, add test using …

…the `lock` keyword (#102222)

- Also removed the `EnablePreviewFeatures` project properties that were added with `Lock` changes
- Added some basic tests with `Lock` using the `lock` keyword

src/coreclr/nativeaot/System.Private.DisabledReflection/src/System.Private.DisabledReflection.csproj

@@ -2,8 +2,6 @@
  <PropertyGroup>
  <!-- we access a lot of internals of System.Private.CoreLib, disable compiling against the ref assembly for now so we don't need to update it -->
  <CompileUsingReferenceAssemblies>false</CompileUsingReferenceAssemblies>
- <!-- CA2252: Opt in to preview features before using them (Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
  <ItemGroup>
  <ProjectReference Include="..\..\System.Private.CoreLib\src\System.Private.CoreLib.csproj" />

src/coreclr/nativeaot/System.Private.Reflection.Execution/src/System.Private.Reflection.Execution.csproj

@@ -8,8 +8,6 @@
  <NativeFormatCommonPath>$(CompilerCommonPath)\Internal\NativeFormat</NativeFormatCommonPath>
  <!-- we access a lot of internals of System.Private.CoreLib, disable compiling against the ref assembly for now so we don't need to update it -->
  <CompileUsingReferenceAssemblies>false</CompileUsingReferenceAssemblies>
- <!-- CA2252: Opt in to preview features before using them (Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
  <ItemGroup>
  <Compile Include="$(NativeFormatCommonPath)\NativeFormat.cs" />

src/coreclr/nativeaot/System.Private.StackTraceMetadata/src/System.Private.StackTraceMetadata.csproj

@@ -2,8 +2,6 @@
  <PropertyGroup>
  <!-- we access a lot of internals of System.Private.CoreLib, disable compiling against the ref assembly for now so we don't need to update it -->
  <CompileUsingReferenceAssemblies>false</CompileUsingReferenceAssemblies>
- <!-- CA2252: Opt in to preview features before using them (Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
 
  <ItemGroup>

src/coreclr/nativeaot/System.Private.TypeLoader/src/System.Private.TypeLoader.csproj

@@ -8,8 +8,6 @@
  <DefineConstants Condition="'$(GENERICS_FORCE_USG)' != ''">GENERICS_FORCE_USG;$(DefineConstants)</DefineConstants>
  <!-- we access a lot of internals of System.Private.CoreLib, disable compiling against the ref assembly for now so we don't need to update it -->
  <CompileUsingReferenceAssemblies>false</CompileUsingReferenceAssemblies>
- <!-- CA2252: Opt in to preview features before using them (Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
  <ItemGroup>
  <ProjectReference Include="..\..\System.Private.CoreLib\src\System.Private.CoreLib.csproj" />

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -4,8 +4,6 @@
  <SharedGUID>c5ed3c1d-b572-46f1-8f96-522a85ce1179</SharedGUID>
  <StringResourcesName Condition="'$(StringResourcesName)' == ''">System.Private.CoreLib.Strings</StringResourcesName>
  <GenerateResourcesSubstitutions>true</GenerateResourcesSubstitutions>
- <!-- CA2252: Opt in to preview features before using them (for System.Threading.Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
  <PropertyGroup Label="Configuration">
  <Import_RootNamespace />

src/libraries/System.Private.CoreLib/src/System/Threading/Lock.cs

@@ -16,7 +16,6 @@ namespace System.Threading
  /// that holds a lock may enter the lock repeatedly without exiting it, such as recursively, in which case the thread should
  /// eventually exit the lock the same number of times to fully exit the lock and allow other threads to enter the lock.
  /// </remarks>
- [Runtime.Versioning.RequiresPreviewFeatures]
  public sealed partial class Lock
  {
  private const short DefaultMaxSpinCount = 22;

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -15164,7 +15164,6 @@ public enum LazyThreadSafetyMode
  PublicationOnly = 1,
  ExecutionAndPublication = 2,
  }
- [System.Runtime.Versioning.RequiresPreviewFeaturesAttribute]
  public sealed partial class Lock
  {
  public Lock() { }

src/libraries/System.Threading/tests/LockTests.cs

@@ -11,6 +11,37 @@ public static class LockTests
  {
  private const int FailTimeoutMilliseconds = 30000;
 
+#pragma warning disable CS9216 // casting Lock to object
+ [Fact]
+ public static void LockStatementWithLockVsMonitor()
+ {
+ Lock lockObj = new();
+ lock (lockObj)
+ {
+ Assert.True(lockObj.IsHeldByCurrentThread);
+ Assert.False(Monitor.IsEntered(lockObj));
+ }
+
+ lock ((object)lockObj)
+ {
+ Assert.False(lockObj.IsHeldByCurrentThread);
+ Assert.True(Monitor.IsEntered(lockObj));
+ }
+
+ LockOnTWhereTIsLock(lockObj);
+
+ static void LockOnTWhereTIsLock<T>(T lockObj) where T : class
+ {
+ Assert.IsType<Lock>(lockObj);
+ lock (lockObj)
+ {
+ Assert.False(((Lock)(object)lockObj).IsHeldByCurrentThread);
+ Assert.True(Monitor.IsEntered(lockObj));
+ }
+ }
+ }
+#pragma warning restore CS9216
+
  // Attempts a single recursive acquisition/release cycle of a newly-created lock.
  [Fact]
  public static void BasicRecursion()
@@ -27,6 +58,10 @@ public static void BasicRecursion()
  {
  Assert.True(lockObj.IsHeldByCurrentThread);
  }
+ lock (lockObj)
+ {
+ Assert.True(lockObj.IsHeldByCurrentThread);
+ }
  Assert.True(lockObj.IsHeldByCurrentThread);
  lockObj.Exit();
  Assert.False(lockObj.IsHeldByCurrentThread);
@@ -64,6 +99,10 @@ public static void IsHeldByCurrentThread()
  {
  Assert.True(lockObj.IsHeldByCurrentThread);
  }
+ lock (lockObj)
+ {
+ Assert.True(lockObj.IsHeldByCurrentThread);
+ }
  Assert.False(lockObj.IsHeldByCurrentThread);
  }
 

src/libraries/System.Threading/tests/System.Threading.Tests.csproj

@@ -4,8 +4,6 @@
  <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
  <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
  <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
- <!-- CA2252: Opt in to preview features before using them (Lock) -->
- <EnablePreviewFeatures>true</EnablePreviewFeatures>
  </PropertyGroup>
  <PropertyGroup Condition="'$(TargetOS)' == 'browser'">
  <XunitShowProgress>true</XunitShowProgress>