use default literal

src/Avalonia.Base/Data/Converters/FuncMultiValueConverter.cs

@@ -38,7 +38,7 @@ namespace Avalonia.Data.Converters
                     }
                     else if (Equals(obj, default(TIn)))
                     {
-                        yield return default(TIn);
+                        yield return default;
                     }
                 }
             }

src/Avalonia.Base/Layout/WrapLayout/UvMeasure.cs

@@ -7,7 +7,7 @@ namespace Avalonia.Layout
 {    
     internal struct UvMeasure
     {
-        internal static readonly UvMeasure Zero = default(UvMeasure);
+        internal static readonly UvMeasure Zero = default;
 
         internal double U { get; set; }
 

src/Avalonia.Base/Media/DrawingContext.cs

@@ -279,7 +279,7 @@ namespace Avalonia.Media
                 OpacityMask,
             }
 
-            public PushedState(DrawingContext context, PushedStateType type, Matrix matrix = default(Matrix))
+            public PushedState(DrawingContext context, PushedStateType type, Matrix matrix = default)
             {
                 if (context._states is null)
                     throw new ObjectDisposedException(nameof(DrawingContext));

src/Avalonia.Base/Media/DrawingGroup.cs

@@ -76,8 +76,8 @@ namespace Avalonia.Media
         {
             using (context.PushPreTransform(Transform?.Value ?? Matrix.Identity))
             using (context.PushOpacity(Opacity))
-            using (ClipGeometry != null ? context.PushGeometryClip(ClipGeometry) : default(DrawingContext.PushedState))
-            using (OpacityMask != null ? context.PushOpacityMask(OpacityMask, GetBounds()) : default(DrawingContext.PushedState))
+            using (ClipGeometry != null ? context.PushGeometryClip(ClipGeometry) : default)
+            using (OpacityMask != null ? context.PushOpacityMask(OpacityMask, GetBounds()) : default)
             {
                 foreach (var drawing in Children)
                 {

src/Avalonia.Base/Media/ImmediateDrawingContext.cs

@@ -218,7 +218,7 @@ namespace Avalonia.Media
                 OpacityMask,
             }
 
-            internal PushedState(ImmediateDrawingContext context, PushedStateType type, Matrix matrix = default(Matrix))
+            internal PushedState(ImmediateDrawingContext context, PushedStateType type, Matrix matrix = default)
             {
                 if (context._states is null)
                     throw new ObjectDisposedException(nameof(ImmediateDrawingContext));

src/Avalonia.Base/Rendering/Composition/Expressions/ExpressionVariant.cs

@@ -654,7 +654,7 @@ namespace Avalonia.Rendering.Composition.Expressions
                 }
             }
 
-            res = default(T);
+            res = default;
             return false;
         }
 

src/Avalonia.Base/Rendering/ImmediateRenderer.cs

@@ -330,11 +330,11 @@ namespace Avalonia.Rendering
                     ? visual is IVisualWithRoundRectClip roundClipVisual
                         ? context.PushClip(new RoundedRect(bounds, roundClipVisual.ClipToBoundsRadius))
                         : context.PushClip(bounds) 
-                    : default(DrawingContext.PushedState))
+                    : default)
 #pragma warning restore CS0618 // Type or member is obsolete
 
-                using (visual.Clip != null ? context.PushGeometryClip(visual.Clip) : default(DrawingContext.PushedState))
-                using (visual.OpacityMask != null ? context.PushOpacityMask(visual.OpacityMask, bounds) : default(DrawingContext.PushedState))
+                using (visual.Clip != null ? context.PushGeometryClip(visual.Clip) : default)
+                using (visual.OpacityMask != null ? context.PushOpacityMask(visual.OpacityMask, bounds) : default)
                 using (context.PushTransformContainer())
                 {
                     visual.Render(context);

src/Avalonia.Base/Rendering/Utilities/TileBrushCalculator.cs

@@ -109,7 +109,7 @@ namespace Avalonia.Rendering.Utilities
             {
                 if (IntermediateTransform != Matrix.Identity)
                     return true;
-                if (SourceRect.Position != default(Point))
+                if (SourceRect.Position != default)
                     return true;
                 if (SourceRect.Size.AspectRatio == _imageSize.AspectRatio)
                     return false;

src/Avalonia.Base/Utilities/SingleOrDictionary.cs

@@ -42,7 +42,7 @@ namespace Avalonia.Utilities
             {
                 if (!_singleValue.HasValue || !EqualityComparer<TKey>.Default.Equals(_singleValue.Value.Key, key))
                 {
-                    value = default(TValue);
+                    value = default;
                     return false;
                 }
                 else

src/Avalonia.Base/Utilities/StringTokenizer.cs

@@ -63,7 +63,7 @@ namespace Avalonia.Utilities
             }
             else
             {
-                result = default(Int32);
+                result = default;
                 return false;
             }
         }
@@ -87,7 +87,7 @@ namespace Avalonia.Utilities
             }
             else
             {
-                result = default(double);
+                result = default;
                 return false;
             }
         }

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -1118,7 +1118,7 @@ namespace Avalonia.Controls
                     EnsureColumnHeadersVisibility();
                     if (!newValueCols)
                     {
-                        _columnHeadersPresenter.Measure(default(Size));
+                        _columnHeadersPresenter.Measure(default);
                     }
                     else
                     {
@@ -1159,7 +1159,7 @@ namespace Avalonia.Controls
                 _topLeftCornerHeader.IsVisible = newValueRows && newValueCols;
                 if (_topLeftCornerHeader.IsVisible)
                 {
-                    _topLeftCornerHeader.Measure(default(Size));
+                    _topLeftCornerHeader.Measure(default);
                 }
             }
 

src/Avalonia.Controls.DataGrid/IndexToValueTable.cs

@@ -422,7 +422,7 @@ namespace Avalonia.Controls
             else
             {
                 found = false;
-                return default(T);
+                return default;
             }
         }
 

src/Avalonia.Controls/Platform/InProcessDragSource.cs

@@ -41,7 +41,7 @@ namespace Avalonia.Platform
             {
                 _draggedData = data;
                 _lastRoot = null;
-                _lastPosition = default(Point);
+                _lastPosition = default;
                 _allowedEffects = allowedEffects;
 
                 using (_inputManager.PreProcess.OfType<RawPointerEventArgs>().Subscribe(ProcessMouseEvents))

src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs

@@ -500,7 +500,7 @@ namespace Avalonia.Controls.Presenters
 
             if (e.OldValue != null)
             {
-                Offset = default(Vector);
+                Offset = default;
             }
         }
 
@@ -542,7 +542,7 @@ namespace Avalonia.Controls.Presenters
             if (logicalScroll != scrollable.IsLogicalScrollEnabled)
             {
                 UpdateScrollableSubscription(Child);
-                Offset = default(Vector);
+                Offset = default;
                 InvalidateMeasure();
             }
             else if (scrollable.IsLogicalScrollEnabled)

src/Avalonia.Controls/Utils/UndoRedoHelper.cs

@@ -49,7 +49,7 @@ namespace Avalonia.Controls.Utils
 
         public bool TryGetLastState(out TState? _state)
         {
-            _state = default(TState);
+            _state = default;
             if (!IsLastState)
                 return false;
 

src/Avalonia.FreeDesktop/DBusMenu.cs

@@ -36,10 +36,10 @@ namespace Avalonia.FreeDesktop.DBusMenu
     [Dictionary]
     class DBusMenuProperties
     {
-        public uint Version { get; set; } = default (uint);
-        public string? TextDirection { get; set; } = default (string);
-        public string? Status { get; set; } = default (string);
-        public string[]? IconThemePath { get; set; } = default (string[]);
+        public uint Version { get; set; } = default;
+        public string? TextDirection { get; set; } = default;
+        public string? Status { get; set; } = default;
+        public string[]? IconThemePath { get; set; } = default;
     }
 
 

src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs

@@ -25,7 +25,7 @@ namespace Avalonia.LinuxFramebuffer
 
             Surfaces = new object[] { _outputBackend };
 
-            Invalidate(default(Rect));
+            Invalidate(default);
             _inputBackend.Initialize(this, e => Input?.Invoke(e));
         }
 

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -224,9 +224,9 @@ namespace Avalonia.Skia
             var impl = (GeometryImpl) geometry;
             var size = geometry.Bounds.Size;
 
-            using (var fill = brush != null ? CreatePaint(_fillPaint, brush, size) : default(PaintWrapper))
+            using (var fill = brush != null ? CreatePaint(_fillPaint, brush, size) : default)
             using (var stroke = pen?.Brush != null ? CreatePaint(_strokePaint, pen, 
-                size.Inflate(new Thickness(pen?.Thickness / 2 ?? 0))) : default(PaintWrapper))
+                size.Inflate(new Thickness(pen?.Thickness / 2 ?? 0))) : default)
             {
                 if (fill.Paint != null)
                 {

src/Skia/Avalonia.Skia/GeometryImpl.cs

@@ -245,7 +245,7 @@ namespace Avalonia.Skia
             {
                 CachedStrokePath?.Dispose();
                 CachedGeometryRenderBounds = default;
-                _cachedStrokeWidth = default(float);
+                _cachedStrokeWidth = default;
             }
         }
     }

src/Windows/Avalonia.Win32.Interop/Wpf/Direct2DImageSurface.cs

@@ -156,7 +156,7 @@ namespace Avalonia.Win32.Interop.Wpf
             _impl.ImageSource = _image;
 
             RemoveAndDispose(ref _backBuffer);
-            if (size == default(IntSize))
+            if (size == default)
             {
                 _image.Lock();
                 _image.SetBackBuffer(D3DResourceType.IDirect3DSurface9, IntPtr.Zero);
@@ -171,7 +171,7 @@ namespace Avalonia.Win32.Interop.Wpf
         static void RemoveAndDispose<T>(ref T d) where T : IDisposable
         {
             d?.Dispose();
-            d = default(T);
+            d = default;
         }
 
         void Swap()

src/Windows/Avalonia.Win32/DataObject.cs

@@ -205,7 +205,7 @@ namespace Avalonia.Win32
             if (string.IsNullOrEmpty(fmt) || !_wrapped.Contains(fmt))
                 return DV_E_FORMATETC;
 
-            * medium = default(Interop.STGMEDIUM);
+            * medium = default;
             medium->tymed = TYMED.TYMED_HGLOBAL;
             return WriteDataToHGlobal(fmt, ref medium->unionmember);
         }

src/Windows/Avalonia.Win32/OleDropTarget.cs

@@ -121,7 +121,7 @@ namespace Avalonia.Win32
                     _dragDevice,
                     RawDragEventType.DragLeave,
                     _target,
-                    default(Point),
+                    default,
                     null,
                     DragDropEffects.None,
                     RawInputModifiers.None

tests/Avalonia.Controls.UnitTests/Presenters/ItemsPresenterTests_Virtualization_Simple.cs

@@ -569,7 +569,7 @@ namespace Avalonia.Controls.UnitTests.Presenters
                 var target = CreateTarget(itemCount: 10);
                 var items = (IList<string>)target.Items;
                 target.ApplyTemplate();
-                target.Measure(default(Size));
+                target.Measure(default);
                 target.Arrange(default);
 
                 // Check for issue #591: this should not throw.