fix review issues.

src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
@@ -122,15 +123,18 @@ namespace Avalonia.Controls.ApplicationLifetimes
                 lifetimeEvents.ShutdownRequested += OnShutdownRequested;
 
             _cts = new CancellationTokenSource();
-            ShowMainWindow(); // Note due to a bug in the JIT we wrap this in a method, otherwise MainWindow
-                              // gets stuffed into a local var and can not be GCed until after the program stops.
-                              // this method never exits until program end.
+            
+            // Note due to a bug in the JIT we wrap this in a method, otherwise MainWindow
+            // gets stuffed into a local var and can not be GCed until after the program stops.
+            // this method never exits until program end.
+            ShowMainWindow(); 
                               
             Dispatcher.UIThread.MainLoop(_cts.Token);
             Environment.ExitCode = _exitCode;
             return _exitCode;
         }
 
+        [MethodImpl(MethodImplOptions.NoInlining)]
         private void ShowMainWindow()
         {
             MainWindow?.Show();

src/Avalonia.Input/FocusManager.cs

@@ -145,7 +145,7 @@ namespace Avalonia.Input
         /// Notifies the focus manager of a change in focus scope.
         /// </summary>
         /// <param name="scope">The new focus scope.</param>
-        public void SetFocusScope(IFocusScope? scope)
+        public void SetFocusScope(IFocusScope scope)
         {
             scope = scope ?? throw new ArgumentNullException(nameof(scope));