Unpin C# compiler version

eng/Versions.props

@@ -50,8 +50,6 @@
     <ProjectServicingConfiguration Include="Microsoft.NETCore.App.Ref" PatchVersion="0" />
   </ItemGroup>
   <PropertyGroup>
-    <!-- Pin compiler version to workaround: https://github.com/dotnet/runtime/issues/41100 -->
-    <MicrosoftNetCompilersToolsetVersion>3.8.0-2.20403.2</MicrosoftNetCompilersToolsetVersion>
     <!-- Arcade dependencies -->
     <MicrosoftDotNetApiCompatVersion>5.0.0-beta.20459.8</MicrosoftDotNetApiCompatVersion>
     <MicrosoftDotNetBuildTasksFeedVersion>5.0.0-beta.20459.8</MicrosoftDotNetBuildTasksFeedVersion>

src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs

@@ -606,7 +606,7 @@ public static unsafe int QueryInterface(IntPtr pUnk, ref Guid iid, out IntPtr pp
             fixed (Guid* pIID = &iid)
             fixed (IntPtr* p = &ppv)
             {
-                return ((delegate * stdcall <IntPtr, Guid*, IntPtr*, int>)(*(*(void***)pUnk + 0 /* IUnknown.QueryInterface slot */)))(pUnk, pIID, p);
+                return ((delegate* unmanaged<IntPtr, Guid*, IntPtr*, int>)(*(*(void***)pUnk + 0 /* IUnknown.QueryInterface slot */)))(pUnk, pIID, p);
             }
         }
 
@@ -616,7 +616,7 @@ public static unsafe int AddRef(IntPtr pUnk)
             if (pUnk == IntPtr.Zero)
                 throw new ArgumentNullException(nameof(pUnk));
 
-            return ((delegate * stdcall <IntPtr, int>)(*(*(void***)pUnk + 1 /* IUnknown.AddRef slot */)))(pUnk);
+            return ((delegate* unmanaged<IntPtr, int>)(*(*(void***)pUnk + 1 /* IUnknown.AddRef slot */)))(pUnk);
         }
 
         [SupportedOSPlatform("windows")]
@@ -625,7 +625,7 @@ public static unsafe int Release(IntPtr pUnk)
             if (pUnk == IntPtr.Zero)
                 throw new ArgumentNullException(nameof(pUnk));
 
-            return ((delegate * stdcall <IntPtr, int>)(*(*(void***)pUnk + 2 /* IUnknown.Release slot */)))(pUnk);
+            return ((delegate* unmanaged<IntPtr, int>)(*(*(void***)pUnk + 2 /* IUnknown.Release slot */)))(pUnk);
         }
 
         [SupportedOSPlatform("windows")]

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/ComRuntimeHelpers.cs

@@ -262,7 +262,7 @@ public static object GetObjectForVariant(Variant variant)
         // This method is intended for use through reflection and should only be used directly by IUnknownReleaseNotZero
         public static unsafe int IUnknownRelease(IntPtr interfacePointer)
         {
-            return ((delegate* stdcall<IntPtr, int>)(*(*(void***)interfacePointer + 2 /* IUnknown.Release slot */)))(interfacePointer);
+            return ((delegate* unmanaged<IntPtr, int>)(*(*(void***)interfacePointer + 2 /* IUnknown.Release slot */)))(interfacePointer);
         }
 
         // This method is intended for use through reflection and should not be used directly
@@ -291,7 +291,7 @@ public static void IUnknownReleaseNotZero(IntPtr interfacePointer)
             fixed (ExcepInfo* pExcepInfo = &excepInfo)
             fixed (uint* pArgErr = &argErr)
             {
-                var pfnIDispatchInvoke = (delegate* stdcall <IntPtr, int, Guid*, int, ushort, ComTypes.DISPPARAMS*, Variant*, ExcepInfo*, uint*, int>)
+                var pfnIDispatchInvoke = (delegate* unmanaged<IntPtr, int, Guid*, int, ushort, ComTypes.DISPPARAMS*, Variant*, ExcepInfo*, uint*, int>)
                     (*(*(void***)dispatchPointer + 6 /* IDispatch.Invoke slot */));
 
                 int hresult = pfnIDispatchInvoke(dispatchPointer,

src/libraries/System.Net.HttpListener/src/System/Net/Windows/WebSockets/HttpWebSocket.Windows.cs

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.IO;
 using System.Runtime.CompilerServices;
@@ -197,6 +198,7 @@ internal static void ThrowIfConnectionAborted(Stream connection, bool read)
             }
         }
 
+        [DoesNotReturn]
         internal static void ThrowPlatformNotSupportedException_WSPC()
         {
             throw new PlatformNotSupportedException(SR.net_WebSockets_UnsupportedPlatform);

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventCounter.cs

@@ -42,7 +42,7 @@ public EventCounter(string name, EventSource eventSource) : base(name, eventSour
             {
                 bufferedValues[i] = UnusedBufferSlotValue;
             }
-            Volatile.Write(ref _bufferedValues, bufferedValues);
+            _bufferedValues = bufferedValues;
 
             Publish();
         }