Remove virtual generic methods from ValueStore.

src/Avalonia.Base/AvaloniaObject.cs

@@ -16,7 +16,7 @@ namespace Avalonia
     /// <remarks>
     /// This class is analogous to DependencyObject in WPF.
     /// </remarks>
-    public class AvaloniaObject : IAvaloniaObject, IAvaloniaObjectDebug, INotifyPropertyChanged, IValueSink
+    public class AvaloniaObject : IAvaloniaObject, IAvaloniaObjectDebug, INotifyPropertyChanged
     {
         private AvaloniaObject? _inheritanceParent;
         private List<IDisposable>? _directBindings;
@@ -524,7 +524,7 @@ namespace Avalonia
             return _propertyChanged?.GetInvocationList();
         }
 
-        void IValueSink.ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
+        internal void ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
         {
             var property = (StyledPropertyBase<T>)change.Property;
 
@@ -563,7 +563,7 @@ namespace Avalonia
             }
         }
 
-        void IValueSink.Completed<T>(
+        internal void Completed<T>(
             StyledPropertyBase<T> property,
             IPriorityValueEntry entry,
             Optional<T> oldValue) 
@@ -574,7 +574,7 @@ namespace Avalonia
                 oldValue,
                 default,
                 BindingPriority.Unset);
-            ((IValueSink)this).ValueChanged(change);
+            ValueChanged(change);
         }
 
         /// <summary>

src/Avalonia.Base/PropertyStore/BindingEntry.cs

@@ -18,19 +18,19 @@ namespace Avalonia.PropertyStore
     /// <typeparam name="T">The property type.</typeparam>
     internal class BindingEntry<T> : IBindingEntry, IPriorityValueEntry<T>, IObserver<BindingValue<T>>
     {
-        private readonly IAvaloniaObject _owner;
-        private IValueSink _sink;
+        private readonly AvaloniaObject _owner;
+        private ValueOwner<T> _sink;
         private IDisposable? _subscription;
         private bool _isSubscribed;
         private bool _batchUpdate;
         private Optional<T> _value;
 
         public BindingEntry(
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             StyledPropertyBase<T> property,
             IObservable<BindingValue<T>> source,
             BindingPriority priority,
-            IValueSink sink)
+            ValueOwner<T> sink)
         {
             _owner = owner;
             Property = property;
@@ -50,7 +50,7 @@ namespace Avalonia.PropertyStore
         {
             _batchUpdate = false;
 
-            if (_sink is ValueStore)
+            if (_sink.IsValueStore)
                 Start();
         }
 
@@ -113,16 +113,15 @@ namespace Avalonia.PropertyStore
             }
         }
 
-        public void Reparent(IValueSink sink) => _sink = sink;
+        public void Reparent(PriorityValue<T> parent) => _sink = new(parent);
 
         public void RaiseValueChanged(
-            IValueSink sink,
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             AvaloniaProperty property,
             Optional<object?> oldValue,
             Optional<object?> newValue)
         {
-            sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+            owner.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                 owner,
                 (AvaloniaProperty<T>)property,
                 oldValue.Cast<T>(),

src/Avalonia.Base/PropertyStore/ConstantValueEntry.cs

@@ -18,14 +18,14 @@ namespace Avalonia.PropertyStore
     /// <typeparam name="T">The property type.</typeparam>
     internal class ConstantValueEntry<T> : IPriorityValueEntry<T>, IConstantValueEntry
     {
-        private IValueSink _sink;
+        private ValueOwner<T> _sink;
         private Optional<T> _value;
 
         public ConstantValueEntry(
             StyledPropertyBase<T> property,
             T value,
             BindingPriority priority,
-            IValueSink sink)
+            ValueOwner<T> sink)
         {
             Property = property;
             _value = value;
@@ -37,7 +37,7 @@ namespace Avalonia.PropertyStore
             StyledPropertyBase<T> property,
             Optional<T> value,
             BindingPriority priority,
-            IValueSink sink)
+            ValueOwner<T> sink)
         {
             Property = property;
             _value = value;
@@ -62,17 +62,16 @@ namespace Avalonia.PropertyStore
             _sink.Completed(Property, this, oldValue);
         }
 
-        public void Reparent(IValueSink sink) => _sink = sink;
+        public void Reparent(PriorityValue<T> sink) => _sink = new(sink);
         public void Start() { }
 
         public void RaiseValueChanged(
-            IValueSink sink,
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             AvaloniaProperty property,
             Optional<object?> oldValue,
             Optional<object?> newValue)
         {
-            sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+            owner.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                 owner,
                 (AvaloniaProperty<T>)property,
                 oldValue.Cast<T>(),

src/Avalonia.Base/PropertyStore/IPriorityValueEntry.cs

@@ -5,7 +5,6 @@
     /// </summary>
     internal interface IPriorityValueEntry : IValue
     {
-        void Reparent(IValueSink sink);
     }
 
     /// <summary>
@@ -14,5 +13,6 @@
     /// <typeparam name="T">The property type.</typeparam>
     internal interface IPriorityValueEntry<T> : IPriorityValueEntry, IValue<T>
     {
+        void Reparent(PriorityValue<T> parent);
     }
 }

src/Avalonia.Base/PropertyStore/IValue.cs

@@ -11,8 +11,7 @@ namespace Avalonia.PropertyStore
         Optional<object?> GetValue();
         void Start();
         void RaiseValueChanged(
-            IValueSink sink,
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             AvaloniaProperty property,
             Optional<object?> oldValue,
             Optional<object?> newValue);

src/Avalonia.Base/PropertyStore/IValueSink.cs

@@ -1,17 +0,0 @@
-using Avalonia.Data;
-
-namespace Avalonia.PropertyStore
-{
-    /// <summary>
-    /// Represents an entity that can receive change notifications in a <see cref="ValueStore"/>.
-    /// </summary>
-    internal interface IValueSink
-    {
-        void ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change);
-
-        void Completed<T>(
-            StyledPropertyBase<T> property,
-            IPriorityValueEntry entry,
-            Optional<T> oldValue);
-    }
-}

src/Avalonia.Base/PropertyStore/LocalValueEntry.cs

@@ -25,13 +25,12 @@ namespace Avalonia.PropertyStore
         public void Start() { }
 
         public void RaiseValueChanged(
-            IValueSink sink,
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             AvaloniaProperty property,
             Optional<object?> oldValue,
             Optional<object?> newValue)
         {
-            sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+            owner.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                 owner,
                 (AvaloniaProperty<T>)property,
                 oldValue.Cast<T>(),

src/Avalonia.Base/PropertyStore/PriorityValue.cs

@@ -23,10 +23,10 @@ namespace Avalonia.PropertyStore
     /// <see cref="IPriorityValueEntry{T}"/> entries (sorted first by priority and then in the order
     /// they were added) plus a local value.
     /// </remarks>
-    internal class PriorityValue<T> : IPriorityValue, IValue<T>, IValueSink, IBatchUpdate
+    internal class PriorityValue<T> : IPriorityValue, IValue<T>, IBatchUpdate
     {
-        private readonly IAvaloniaObject _owner;
-        private readonly IValueSink _sink;
+        private readonly AvaloniaObject _owner;
+        private readonly ValueStore _store;
         private readonly List<IPriorityValueEntry<T>> _entries = new List<IPriorityValueEntry<T>>();
         private readonly Func<IAvaloniaObject, T, T>? _coerceValue;
         private Optional<T> _localValue;
@@ -35,13 +35,13 @@ namespace Avalonia.PropertyStore
         private bool _batchUpdate;
 
         public PriorityValue(
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             StyledPropertyBase<T> property,
-            IValueSink sink)
+            ValueStore store)
         {
             _owner = owner;
             Property = property;
-            _sink = sink;
+            _store = store;
 
             if (property.HasCoercion)
             {
@@ -51,11 +51,11 @@ namespace Avalonia.PropertyStore
         }
 
         public PriorityValue(
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             StyledPropertyBase<T> property,
-            IValueSink sink,
+            ValueStore store,
             IPriorityValueEntry<T> existing)
-            : this(owner, property, sink)
+            : this(owner, property, store)
         {
             existing.Reparent(this);
             _entries.Add(existing);
@@ -82,9 +82,9 @@ namespace Avalonia.PropertyStore
         }
 
         public PriorityValue(
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             StyledPropertyBase<T> property,
-            IValueSink sink,
+            ValueStore sink,
             LocalValueEntry<T> existing)
             : this(owner, property, sink)
         {
@@ -155,7 +155,7 @@ namespace Avalonia.PropertyStore
             else
             {
                 var insert = FindInsertPoint(priority);
-                var entry = new ConstantValueEntry<T>(Property, value, priority, this);
+                var entry = new ConstantValueEntry<T>(Property, value, priority, new ValueOwner<T>(this));
                 _entries.Insert(insert, entry);
                 result = entry;
             }
@@ -172,7 +172,7 @@ namespace Avalonia.PropertyStore
 
         public BindingEntry<T> AddBinding(IObservable<BindingValue<T>> source, BindingPriority priority)
         {
-            var binding = new BindingEntry<T>(_owner, Property, source, priority, this);
+            var binding = new BindingEntry<T>(_owner, Property, source, priority, new(this));
             var insert = FindInsertPoint(binding.Priority);
             _entries.Insert(insert, binding);
 
@@ -193,13 +193,12 @@ namespace Avalonia.PropertyStore
         public void Start() => UpdateEffectiveValue(null);
 
         public void RaiseValueChanged(
-            IValueSink sink,
-            IAvaloniaObject owner,
+            AvaloniaObject owner,
             AvaloniaProperty property,
             Optional<object?> oldValue,
             Optional<object?> newValue)
         {
-            sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+            owner.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                 owner,
                 (AvaloniaProperty<T>)property,
                 oldValue.Cast<T>(),
@@ -207,7 +206,7 @@ namespace Avalonia.PropertyStore
                 Priority));
         }
 
-        void IValueSink.ValueChanged<TValue>(AvaloniaPropertyChangedEventArgs<TValue> change)
+        public void ValueChanged<TValue>(AvaloniaPropertyChangedEventArgs<TValue> change)
         {
             if (change.Priority == BindingPriority.LocalValue)
             {
@@ -220,22 +219,15 @@ namespace Avalonia.PropertyStore
             }
         }
 
-        void IValueSink.Completed<TValue>(
-            StyledPropertyBase<TValue> property,
-            IPriorityValueEntry entry,
-            Optional<TValue> oldValue)
+        public void Completed(IPriorityValueEntry entry, Optional<T> oldValue)
         {
             _entries.Remove((IPriorityValueEntry<T>)entry);
-
-            if (oldValue is Optional<T> o)
-            {
-                UpdateEffectiveValue(new AvaloniaPropertyChangedEventArgs<T>(
-                    _owner,
-                    Property,
-                    o,
-                    default,
-                    entry.Priority));
-            }
+            UpdateEffectiveValue(new AvaloniaPropertyChangedEventArgs<T>(
+                _owner,
+                Property,
+                oldValue,
+                default,
+                entry.Priority));
         }
 
         private int FindInsertPoint(BindingPriority priority)
@@ -315,7 +307,7 @@ namespace Avalonia.PropertyStore
                 var old = _value;
                 _value = value;
 
-                _sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+                _store.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                     _owner,
                     Property,
                     old,
@@ -326,7 +318,7 @@ namespace Avalonia.PropertyStore
             {
                 change.MarkNonEffectiveValue();
                 change.SetOldValue(default);
-                _sink.ValueChanged(change);
+                _store.ValueChanged(change);
             }
         }
     }

src/Avalonia.Base/PropertyStore/ValueOwner.cs

@@ -0,0 +1,45 @@
+using Avalonia.Data;
+
+namespace Avalonia.PropertyStore
+{
+    /// <summary>
+    /// Represents a union type of <see cref="ValueStore"/> and <see cref="PriorityValue{T}"/>,
+    /// which are the valid owners of a value store <see cref="IValue"/>.
+    /// </summary>
+    /// <typeparam name="T">The value type.</typeparam>
+    internal readonly struct ValueOwner<T>
+    {
+        private readonly ValueStore? _store;
+        private readonly PriorityValue<T>? _priorityValue;
+
+        public ValueOwner(ValueStore o)
+        {
+            _store = o;
+            _priorityValue = null;
+        }
+
+        public ValueOwner(PriorityValue<T> v)
+        {
+            _store = null;
+            _priorityValue = v;
+        }
+
+        public bool IsValueStore => _store is not null;
+
+        public void Completed(StyledPropertyBase<T> property, IPriorityValueEntry entry, Optional<T> oldValue)
+        {
+            if (_store is not null)
+                _store?.Completed(property, entry, oldValue);
+            else
+                _priorityValue!.Completed(entry, oldValue);
+        }
+
+        public void ValueChanged(AvaloniaPropertyChangedEventArgs<T> e)
+        {
+            if (_store is not null)
+                _store?.ValueChanged(e);
+            else
+                _priorityValue!.ValueChanged(e);
+        }
+    }
+}

src/Avalonia.Base/ValueStore.cs

@@ -21,16 +21,15 @@ namespace Avalonia
     /// - For a single binding it will be an instance of <see cref="BindingEntry{T}"/>
     /// - For all other cases it will be an instance of <see cref="PriorityValue{T}"/>
     /// </remarks>
-    internal class ValueStore : IValueSink
+    internal class ValueStore
     {
         private readonly AvaloniaObject _owner;
-        private readonly IValueSink _sink;
         private readonly AvaloniaPropertyValueStore<IValue> _values;
         private BatchUpdate? _batchUpdate;
 
         public ValueStore(AvaloniaObject owner)
         {
-            _sink = _owner = owner;
+            _owner = owner;
             _values = new AvaloniaPropertyValueStore<IValue>();
         }
 
@@ -122,7 +121,7 @@ namespace Avalonia
                 }
                 else
                 {
-                    var entry = new ConstantValueEntry<T>(property, value, priority, this);
+                    var entry = new ConstantValueEntry<T>(property, value, priority, new(this));
                     AddValue(property, entry);
                     NotifyValueChanged<T>(property, default, value, priority);
                     result = entry;
@@ -151,7 +150,7 @@ namespace Avalonia
             }
             else
             {
-                var entry = new BindingEntry<T>(_owner, property, source, priority, this);
+                var entry = new BindingEntry<T>(_owner, property, source, priority, new(this));
                 AddValue(property, entry);
                 return entry;
             }
@@ -187,7 +186,7 @@ namespace Avalonia
                         // so there's no way to mark them for removal at the end of a batch update. Instead convert
                         // them to a constant value entry with Unset priority in the event of a local value being
                         // cleared during a batch update.
-                        var sentinel = new ConstantValueEntry<T>(property, Optional<T>.Empty, BindingPriority.Unset, _sink);
+                        var sentinel = new ConstantValueEntry<T>(property, Optional<T>.Empty, BindingPriority.Unset, new(this));
                         _values.SetValue(property, sentinel);
                     }
 
@@ -222,7 +221,7 @@ namespace Avalonia
             return null;
         }
 
-        void IValueSink.ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
+        public void ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
         {
             if (_batchUpdate is object)
             {
@@ -233,11 +232,11 @@ namespace Avalonia
             }
             else
             {
-                _sink.ValueChanged(change);
+                _owner.ValueChanged(change);
             }
         }
 
-        void IValueSink.Completed<T>(
+        public void Completed<T>(
             StyledPropertyBase<T> property,
             IPriorityValueEntry entry,
             Optional<T> oldValue)
@@ -248,7 +247,7 @@ namespace Avalonia
                 if (_batchUpdate is null)
                 {
                     _values.Remove(property);
-                    _sink.Completed(property, entry, oldValue);
+                    _owner.Completed(property, entry, oldValue);
                 }
                 else
                 {
@@ -352,7 +351,7 @@ namespace Avalonia
         {
             if (_batchUpdate is null)
             {
-                _sink.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
+                _owner.ValueChanged(new AvaloniaPropertyChangedEventArgs<T>(
                     _owner,
                     property,
                     oldValue,
@@ -451,7 +450,7 @@ namespace Avalonia
                             };
 
                             // Call _sink.ValueChanged with an appropriately typed AvaloniaPropertyChangedEventArgs<T>.
-                            slot.RaiseValueChanged(_owner._sink, _owner._owner, entry.property, oldValue, newValue);
+                            slot.RaiseValueChanged(_owner._owner, entry.property, oldValue, newValue);
 
                             // During batch update values can't be removed immediately because they're needed to raise
                             // the _sink.ValueChanged notification. They instead mark themselves for removal by setting

tests/Avalonia.Base.UnitTests/PriorityValueTests.cs

@@ -10,8 +10,8 @@ namespace Avalonia.Base.UnitTests
 {
     public class PriorityValueTests
     {
-        private static readonly IValueSink NullSink = new MockSink();
-        private static readonly IAvaloniaObject Owner = Mock.Of<IAvaloniaObject>();
+        private static readonly AvaloniaObject Owner = new AvaloniaObject();
+        private static readonly ValueStore ValueStore = new ValueStore(Owner);
         private static readonly StyledProperty<string> TestProperty = new StyledProperty<string>(
             "Test",
             typeof(PriorityValueTests),
@@ -23,12 +23,12 @@ namespace Avalonia.Base.UnitTests
             var target = new PriorityValue<string>(
                 Owner,
                 TestProperty,
-                NullSink,
+                ValueStore,
                 new ConstantValueEntry<string>(
                     TestProperty,
                     "1",
                     BindingPriority.StyleTrigger,
-                    NullSink));
+                    new(ValueStore)));
 
             Assert.Equal("1", target.GetValue().Value);
             Assert.Equal(BindingPriority.StyleTrigger, target.Priority);
@@ -40,7 +40,7 @@ namespace Avalonia.Base.UnitTests
             var target = new PriorityValue<string>(
                 Owner,
                 TestProperty,
-                NullSink);
+                ValueStore);
 
             target.SetValue("animation", BindingPriority.Animation);
             target.SetValue("local", BindingPriority.LocalValue);
@@ -60,7 +60,7 @@ namespace Avalonia.Base.UnitTests
             var target = new PriorityValue<string>(
                 Owner,
                 TestProperty,
-                NullSink);
+                ValueStore);
 
             target.SetValue("1", BindingPriority.LocalValue);
             target.SetValue("2", BindingPriority.LocalValue);
@@ -74,7 +74,7 @@ namespace Avalonia.Base.UnitTests
             var target = new PriorityValue<string>(
                 Owner,
                 TestProperty,
-                NullSink);
+                ValueStore);
 
             target.SetValue("1", BindingPriority.Style);
             target.SetValue("2", BindingPriority.Animation);
@@ -93,7 +93,7 @@ namespace Avalonia.Base.UnitTests
             var target = new PriorityValue<string>(
                 Owner,
                 TestProperty,
-                NullSink);
+                ValueStore);
 
             Assert.Equal(BindingPriority.Unset, target.Priority);
             target.SetValue("style", BindingPriority.Style);
@@ -109,7 +109,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Binding_With_Same_Priority_Should_Be_Appended()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
 
@@ -129,7 +129,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Binding_With_Higher_Priority_Should_Be_Appended()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
 
@@ -149,7 +149,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Binding_With_Lower_Priority_Should_Be_Prepended()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
 
@@ -169,7 +169,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Second_Binding_With_Lower_Priority_Should_Be_Inserted_In_Middle()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
             var source3 = new Source("3");
@@ -191,7 +191,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Competed_Binding_Should_Be_Removed()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
             var source3 = new Source("3");
@@ -214,7 +214,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void Value_Should_Come_From_Last_Entry()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
             var source3 = new Source("3");
@@ -229,7 +229,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void LocalValue_Should_Override_LocalValue_Binding()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
 
             target.AddBinding(source1, BindingPriority.LocalValue).Start();
@@ -241,7 +241,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void LocalValue_Should_Override_Style_Binding()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
 
             target.AddBinding(source1, BindingPriority.Style).Start();
@@ -253,7 +253,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void LocalValue_Should_Not_Override_Animation_Binding()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
 
             target.AddBinding(source1, BindingPriority.Animation).Start();
@@ -265,7 +265,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void NonAnimated_Value_Should_Be_Correct_1()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
             var source3 = new Source("3");
@@ -281,7 +281,7 @@ namespace Avalonia.Base.UnitTests
         [Fact]
         public void NonAnimated_Value_Should_Be_Correct_2()
         {
-            var target = new PriorityValue<string>(Owner, TestProperty, NullSink);
+            var target = new PriorityValue<string>(Owner, TestProperty, ValueStore);
             var source1 = new Source("1");
             var source2 = new Source("2");
             var source3 = new Source("3");
@@ -310,16 +310,5 @@ namespace Avalonia.Base.UnitTests
 
             public void OnCompleted() => _observer.OnCompleted();
         }
-
-        private class MockSink : IValueSink
-        {
-            public void Completed<T>(StyledPropertyBase<T> property, IPriorityValueEntry entry, Optional<T> oldValue)
-            {
-            }
-
-            public void ValueChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
-            {
-            }
-        }
     }
 }