Misc warning fixes (#14766)

* Fix XML doc warnings

* Fix nullability warnings

* Fix misc warnings

src/Android/Avalonia.Android/AndroidRuntimePlatform.cs

@@ -1,4 +1,6 @@
-using System;
+#nullable enable
+
+using System;
 using Android.Content.PM;
 using Android.Content;
 using Avalonia.Platform;
@@ -27,7 +29,7 @@ namespace Avalonia
 
     internal class AndroidRuntimePlatform : StandardRuntimePlatform
     {
-        private static readonly Lazy<RuntimePlatformInfo> Info = new(() =>
+        private static readonly Lazy<RuntimePlatformInfo> s_info = new(() =>
         {
             var isDesktop = IsRunningOnDesktop(App.Context);
             var isTv = IsRunningOnTv(App.Context);
@@ -41,12 +43,13 @@ namespace Avalonia
         });
 
         private static bool IsRunningOnDesktop(Context context) =>
-            context.PackageManager.HasSystemFeature("org.chromium.arc") ||
-            context.PackageManager.HasSystemFeature("org.chromium.arc.device_management");
+            context.PackageManager is { } packageManager &&
+            (packageManager.HasSystemFeature("org.chromium.arc") ||
+             packageManager.HasSystemFeature("org.chromium.arc.device_management"));
 
         private static bool IsRunningOnTv(Context context) => 
-            context.PackageManager.HasSystemFeature(PackageManager.FeatureLeanback);
+            context.PackageManager?.HasSystemFeature(PackageManager.FeatureLeanback) == true;
 
-        public override RuntimePlatformInfo GetRuntimeInfo() => Info.Value;
+        public override RuntimePlatformInfo GetRuntimeInfo() => s_info.Value;
     }
 }

src/Avalonia.Base/Data/Core/ExpressionNodes/Reflection/ReflectionIndexerNode.cs

@@ -15,7 +15,7 @@ namespace Avalonia.Data.Core.ExpressionNodes.Reflection;
 [RequiresUnreferencedCode(TrimmingMessages.ReflectionBindingRequiresUnreferencedCodeMessage)]
 internal sealed class ReflectionIndexerNode : CollectionNodeBase, ISettableNode
 {
-    private static readonly BindingFlags InstanceFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly;
+    private const BindingFlags InstanceFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly;
     private MethodInfo? _getter;
     private MethodInfo? _setter;
     private object?[]? _indexes;

src/Avalonia.Base/Data/Core/ExpressionParseException.cs

@@ -3,8 +3,7 @@ using System;
 namespace Avalonia.Data.Core
 {
     /// <summary>
-    /// Exception thrown when <see cref="ExpressionObserver"/> could not parse the provided
-    /// expression string.
+    /// Exception thrown when the provided binding expression string could not be parsed.
     /// </summary>
 #if !BUILDTASK
     public

src/Avalonia.Base/Data/Core/Parsers/BindingExpressionVisitor.cs

@@ -15,7 +15,7 @@ internal class BindingExpressionVisitor<TIn> : ExpressionVisitor
 {
     private static readonly PropertyInfo AvaloniaObjectIndexer;
     private static readonly MethodInfo CreateDelegateMethod;
-    private static readonly string IndexerGetterName = "get_Item";
+    private const string IndexerGetterName = "get_Item";
     private const string MultiDimensionalArrayGetterMethodName = "Get";
     private readonly bool _enableDataValidation;
     private readonly LambdaExpression _rootExpression;

src/Avalonia.Base/Data/Core/UntypedBindingExpressionBase.cs

@@ -140,8 +140,7 @@ public abstract class UntypedBindingExpressionBase : BindingExpressionBase,
     }
 
     /// <summary>
-    /// Starts the binding expression following a call to 
-    /// <see cref="AttachCore(IBindingExpressionSink, AvaloniaObject, AvaloniaProperty, BindingPriority)"/>.
+    /// Starts the binding expression following a call to <see cref="AttachCore"/>.
     /// </summary>
     public void Start() => Start(produceValue: true);
 

src/Avalonia.Base/Media/FormattedText.cs

@@ -51,7 +51,6 @@ namespace Avalonia.Media
         /// <param name="typeface">Type face used to display text.</param>
         /// <param name="emSize">Font em size in visual units (1/96 of an inch).</param>
         /// <param name="foreground">Foreground brush used to render text.</param>
-        /// <param name="features">Optional list of turned on/off features.</param>
         public FormattedText(
             string textToFormat,
             CultureInfo culture,

src/Avalonia.Base/Rendering/Composition/Compositor.cs

@@ -294,7 +294,7 @@ namespace Avalonia.Rendering.Composition
             _objectSerializationHashSet.Contains(serializable);
 
         /// <summary>
-        /// Attempts to get the Compositor instance that will be used by default for new <see cref="Avalonia.Controls.TopLevel"/>s
+        /// Attempts to get the Compositor instance that will be used by default for new TopLevels
         /// created by the current platform backend.
         ///
         /// This won't work for every single platform backend and backend settings, e. g. with web we'll need to have

src/Avalonia.Controls.ColorPicker/Helpers/ColorPickerHelpers.cs

@@ -24,6 +24,7 @@ namespace Avalonia.Controls.Primitives
         /// Generates a new bitmap of the specified size by changing a specific color component.
         /// This will produce a gradient representing a sweep of all possible values of the color component.
         /// </summary>
+        /// <param name="bgraPixelData">The target buffer which will contain the bitmap data on return.</param>
         /// <param name="width">The pixel width (X, horizontal) of the resulting bitmap.</param>
         /// <param name="height">The pixel height (Y, vertical) of the resulting bitmap.</param>
         /// <param name="orientation">The orientation of the resulting bitmap (gradient direction).</param>

src/Avalonia.Controls/NativeMenuItem.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Windows.Input;
+using Avalonia.Controls.Primitives;
 using Avalonia.Input;
 using Avalonia.Media.Imaging;
 using Avalonia.Metadata;
@@ -65,11 +66,11 @@ namespace Avalonia.Controls
             set => SetValue(IconProperty, value);
         }
 
-        /// <inheritdoc cref="MenuItem.HeaderProperty"/>
+        /// <inheritdoc cref="HeaderedSelectingItemsControl.HeaderProperty"/>
         public static readonly StyledProperty<string?> HeaderProperty =
             AvaloniaProperty.Register<NativeMenuItem, string?>(nameof(Header));
 
-        /// <inheritdoc cref="MenuItem.Header"/>
+        /// <inheritdoc cref="HeaderedSelectingItemsControl.Header"/>
         public string? Header
         {
             get => GetValue(HeaderProperty);
@@ -134,10 +135,11 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<object?> CommandParameterProperty =
             MenuItem.CommandParameterProperty.AddOwner<NativeMenuItem>();
 
+        /// <inheritdoc cref="InputElement.IsEnabledProperty"/>
         public static readonly StyledProperty<bool> IsEnabledProperty =
            AvaloniaProperty.Register<NativeMenuItem, bool>(nameof(IsEnabled), true);
 
-        /// <inheritdoc cref="MenuItem.IsEnabled"/>
+        /// <inheritdoc cref="InputElement.IsEnabled"/>
         public bool IsEnabled
         {
             get => GetValue(IsEnabledProperty);

src/Avalonia.Controls/PullToRefresh/RefreshVisualizer.cs

@@ -14,7 +14,6 @@ namespace Avalonia.Controls
 {
     public class RefreshVisualizer : ContentControl
     {
-        private const int DefaultIndicatorSize = 24;
         private const float MinimumIndicatorOpacity = 0.4f;
         private const float ParallaxPositionRatio = 0.5f;
         private double _executingRatio = 0.8;

src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlControlTemplatePartsChecker.cs

@@ -1,4 +1,6 @@
-using System.Collections.Generic;
+#nullable enable
+
+using System.Collections.Generic;
 using System.Linq;
 using XamlX;
 using XamlX.Ast;

tests/Avalonia.Base.UnitTests/Data/Core/BindingExpressionTests.UpdateSourceTrigger.cs

@@ -1,3 +1,5 @@
+#nullable enable
+
 using Avalonia.Data;
 using Avalonia.UnitTests;
 using Xunit;

tests/Avalonia.Base.UnitTests/DispatcherTests.Exception.cs

@@ -265,7 +265,7 @@ public partial class DispatcherTests
             dispatcher.Post(ThrowAnException, DispatcherPriority.Normal);
             dispatcher.RunJobs();
         }
-        catch (Exception e)
+        catch (Exception)
         {
             // should be no exception here.
             caughtCorrectException = false;

tests/Avalonia.Base.UnitTests/Input/KeyboardNavigationTests_XY.cs

@@ -350,11 +350,11 @@ public class KeyboardNavigationTests_XY : ScopedTestBase
     }
     
     [Theory]
-    [InlineData(Key.Left, NavigationDirection.Left)]
-    [InlineData(Key.Right, NavigationDirection.Right)]
-    [InlineData(Key.Up, NavigationDirection.Up)]
-    [InlineData(Key.Down, NavigationDirection.Down)]
-    public void Arrow_Key_Should_Not_Be_Handled_If_No_Focus(Key key, NavigationDirection direction)
+    [InlineData(Key.Left)]
+    [InlineData(Key.Right)]
+    [InlineData(Key.Up)]
+    [InlineData(Key.Down)]
+    public void Arrow_Key_Should_Not_Be_Handled_If_No_Focus(Key key)
     {
         using var _ = UnitTestApplication.Start(TestServices.FocusableWindow);
         

tests/Avalonia.Controls.UnitTests/VirtualizingStackPanelTests.cs

@@ -1144,7 +1144,7 @@ namespace Avalonia.Controls.UnitTests
             {
                 ev.Container.AddHandler(Control.RequestBringIntoViewEvent, (_, e) =>
                 {
-                    var dataContext = e.TargetObject.DataContext as ItemWithHeight;
+                    var dataContext = (ItemWithHeight)e.TargetObject!.DataContext!;
                     e.TargetRect = new Rect(dataContext.Height - 50, 0, 50, 10);
                 });
             };

tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs

@@ -1005,7 +1005,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.MarkupExtensions
     </Button>
 </Window>";
                 var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
-                var button = window.FindControl<Button>("button");
+                var button = window.GetControl<Button>("button");
 
                 button.Tag = new GridLength(5, GridUnitType.Star);
 
@@ -1985,7 +1985,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.MarkupExtensions
     <TextBlock Name='textBlock' Tag='{{Binding !BoolProperty}}'/>
 </Window>";
                 var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
-                var textBlock = window.FindControl<TextBlock>("textBlock");
+                var textBlock = window.GetControl<TextBlock>("textBlock");
 
                 var dataContext = new TestDataContext { BoolProperty = value };
                 window.DataContext = dataContext;
@@ -2013,7 +2013,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.MarkupExtensions
     </TextBlock>
 </Window>";
                 var window = (Window)AvaloniaRuntimeXamlLoader.Load(xaml);
-                var textBlock = window.FindControl<TextBlock>("textBlock");
+                var textBlock = window.GetControl<TextBlock>("textBlock");
 
                 var dataContext = new ImplicitConvertible("Green");
                 window.DataContext = dataContext;

tests/Avalonia.RenderTests/Media/RelativePointTestPrimitivesHelper.cs

@@ -17,8 +17,8 @@ namespace Avalonia.Direct2D1.RenderTests.Media
     {
         private readonly IBrush? _brush;
         private readonly bool _shadow;
-        private readonly IPen _line;
-        private static readonly Geometry s_Geometry = Geometry.Parse("m 80 200 c 40 20 150 -40 160 0 l 0 30 c -40 -30 -160 10 -160 -30 z");
+        private readonly IPen? _line;
+        private static readonly Geometry s_geometry = Geometry.Parse("m 80 200 c 40 20 150 -40 160 0 l 0 30 c -40 -30 -160 10 -160 -30 z");
 
         public RelativePointTestPrimitivesHelper(IBrush? brush, bool shadow = false)
         {
@@ -42,8 +42,9 @@ namespace Avalonia.Direct2D1.RenderTests.Media
 
             context.DrawRectangle(_brush, null, new Rect(20, 20, 200, 60));
             context.DrawEllipse(_brush, null, new Rect(40, 100, 200, 20));
-            context.DrawLine(_line, new Point(60, 140), new Point(240, 160));
-            context.DrawGeometry(_brush, null, s_Geometry);
+            if (_line is not null)
+                context.DrawLine(_line, new Point(60, 140), new Point(240, 160));
+            context.DrawGeometry(_brush, null, s_geometry);
             
             base.Render(context);
         }