Fix merge

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

@@ -5,7 +5,7 @@ using System.Text;
 
 namespace Avalonia.Data.Core
 {
-    public class AvaloniaPropertyAccessorNode : ExpressionNode, ISettableNode
+    public class AvaloniaPropertyAccessorNode : SettableNode
     {
         private readonly bool _enableValidation;
         private readonly AvaloniaProperty _property;
@@ -18,9 +18,9 @@ namespace Avalonia.Data.Core
 
         public override string Description => PropertyName;
         public string PropertyName { get; }
-        public Type PropertyType => _property.PropertyType;
+        public override Type PropertyType => _property.PropertyType;
 
-        public bool SetTargetValue(object value, BindingPriority priority)
+        protected override bool SetTargetValueCore(object value, BindingPriority priority)
         {
             try
             {

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

@@ -34,7 +34,7 @@ namespace Avalonia.Data.Core
 
         public override string Description => expression.ToString();
 
-        public override bool SetTargetValue(object value, BindingPriority priority)
+        protected override bool SetTargetValueCore(object value, BindingPriority priority)
         {
             try
             {

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

@@ -13,7 +13,7 @@ using Avalonia.Utilities;
 
 namespace Avalonia.Data.Core
 {
-    public abstract class IndexerNodeBase : ExpressionNode, ISettableNode
+    public abstract class IndexerNodeBase : SettableNode
     {
         protected override IObservable<object> StartListeningCore(WeakReference reference)
         {
@@ -41,10 +41,6 @@ namespace Avalonia.Data.Core
             return inputs.Merge().StartWith(GetValue(target));
         }
 
-        public abstract bool SetTargetValue(object value, BindingPriority priority);
-
-        public abstract Type PropertyType { get; }
-
         protected abstract object GetValue(object target);
 
         protected abstract int? TryGetFirstArgumentAsInt();

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

@@ -7,7 +7,7 @@ using System.Threading.Tasks;
 
 namespace Avalonia.Data.Core
 {
-    internal abstract class SettableNode : ExpressionNode
+    public abstract class SettableNode : ExpressionNode
     {
         public bool SetTargetValue(object value, BindingPriority priority)
         {

src/Markup/Avalonia.Markup/Markup/Parsers/Nodes/StringIndexerNode.cs

@@ -25,7 +25,7 @@ namespace Avalonia.Markup.Parsers.Nodes
 
         public override string Description => "[" + string.Join(",", Arguments) + "]";
 
-        public override bool SetTargetValue(object value, BindingPriority priority)
+        protected override bool SetTargetValueCore(object value, BindingPriority priority)
         {
             var typeInfo = Target.Target.GetType().GetTypeInfo();
             var list = Target.Target as IList;