Fix namescope searching to recursively search parent namescopes up to the root namescope and never find a name in a namescope that is not a direct ancestor of the current namescope.

src/Markup/Avalonia.Markup.Xaml/XamlIl/CompilerExtensions/Transformers/AddNameScopeRegistration.cs

@@ -10,42 +10,49 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
     {
         public IXamlIlAstNode Transform(XamlIlAstTransformationContext context, IXamlIlAstNode node)
         {
-            if (node is XamlIlPropertyAssignmentNode pa
-                && pa.Property.Name == "Name"
-                && pa.Property.DeclaringType.FullName == "Avalonia.StyledElement")
+            if (node is XamlIlPropertyAssignmentNode pa)
             {
-                if (context.ParentNodes().FirstOrDefault() is XamlIlManipulationGroupNode mg
-                    && mg.Children.OfType<ScopeRegistrationNode>().Any())
-                    return node;
+                if (pa.Property.Name == "Name"
+                    && pa.Property.DeclaringType.FullName == "Avalonia.StyledElement")
+                {
+                    if (context.ParentNodes().FirstOrDefault() is XamlIlManipulationGroupNode mg
+                        && mg.Children.OfType<ScopeRegistrationNode>().Any())
+                        return node;
                 
-                IXamlIlAstValueNode value = null;
-                for (var c = 0; c < pa.Values.Count; c++)
-                    if (pa.Values[c].Type.GetClrType().Equals(context.Configuration.WellKnownTypes.String))
-                    {
-                        value = pa.Values[c];
-                        if (!(value is XamlIlAstTextNode))
+                    IXamlIlAstValueNode value = null;
+                    for (var c = 0; c < pa.Values.Count; c++)
+                        if (pa.Values[c].Type.GetClrType().Equals(context.Configuration.WellKnownTypes.String))
                         {
-                            var local = new XamlIlAstCompilerLocalNode(value);
-                            // Wrap original in local initialization
-                            pa.Values[c] = new XamlIlAstLocalInitializationNodeEmitter(value, value, local);
-                            // Use local
-                            value = local;
-                        }
+                            value = pa.Values[c];
+                            if (!(value is XamlIlAstTextNode))
+                            {
+                                var local = new XamlIlAstCompilerLocalNode(value);
+                                // Wrap original in local initialization
+                                pa.Values[c] = new XamlIlAstLocalInitializationNodeEmitter(value, value, local);
+                                // Use local
+                                value = local;
+                            }
 
-                        break;
-                    }
+                            break;
+                        }
 
-                if (value != null)
-                {
-                    var objectType = context.ParentNodes().OfType<XamlIlAstObjectNode>().FirstOrDefault()?.Type.GetClrType();
-                    return new XamlIlManipulationGroupNode(pa)
+                    if (value != null)
                     {
-                        Children =
+                        var objectType = context.ParentNodes().OfType<XamlIlAstObjectNode>().FirstOrDefault()?.Type.GetClrType();
+                        return new XamlIlManipulationGroupNode(pa)
                         {
-                            pa,
-                            new ScopeRegistrationNode(value, objectType)
-                        }
-                    };
+                            Children =
+                            {
+                                pa,
+                                new ScopeRegistrationNode(value, objectType)
+                            }
+                        };
+                    }
+                }
+                else if (pa.Property.CustomAttributes.Select(attr => attr.Type).Intersect(context.Configuration.TypeMappings.DeferredContentPropertyAttributes).Any())
+                {
+                    pa.Values[pa.Values.Count - 1] =
+                        new NestedScopeMetadataNode(pa.Values[pa.Values.Count - 1]);
                 }
             }
 
@@ -53,6 +60,13 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
         }
     }
 
+    class NestedScopeMetadataNode : XamlIlValueWithSideEffectNodeBase
+    {
+        public NestedScopeMetadataNode(IXamlIlAstValueNode value) : base(value, value)
+        {
+        }
+    }
+
     class ScopeRegistrationNode : XamlIlAstNode, IXamlIlAstManipulationNode, IXamlIlAstEmitableNode
     {
         public IXamlIlAstValueNode Value { get; set; }

src/Markup/Avalonia.Markup.Xaml/XamlIl/CompilerExtensions/Transformers/AvaloniaXamlIlMetadataRemover.cs

@@ -14,6 +14,9 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             if (node is AvaloniaXamlIlDataContextTypeMetadataNode dataContextTypeMetadata)
                 return dataContextTypeMetadata.Value;
 
+            if (node is NestedScopeMetadataNode nestedScope)
+                return nestedScope.Value;
+
             return node;
         }
     }

src/Markup/Avalonia.Markup.Xaml/XamlIl/CompilerExtensions/XamlIlBindingPathHelper.cs

@@ -180,7 +180,20 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
                         nodes.Add(new FindAncestorPathElementNode(GetType(ancestor.Namespace, ancestor.TypeName), ancestor.Level));
                         break;
                     case BindingExpressionGrammar.NameNode elementName:
-                        var elementType = ScopeRegistrationFinder.GetControlType(context, context.RootObject, elementName.Name);
+                        IXamlIlType elementType = null;
+                        foreach (var deferredContent in context.ParentNodes().OfType<NestedScopeMetadataNode>())
+                        {
+                            elementType = ScopeRegistrationFinder.GetControlType(deferredContent, elementName.Name);
+                            if (!(elementType is null))
+                            {
+                                break;
+                            }
+                        }
+                        if (elementType is null)
+                        {
+                            elementType = ScopeRegistrationFinder.GetControlType(context.RootObject, elementName.Name);
+                        }
+
                         if (elementType is null)
                         {
                             throw new XamlIlParseException($"Unable to find element '{elementName.Name}' in the current namescope. Unable to use a compiled binding with a name binding if the name cannot be found at compile time.", lineInfo);
@@ -199,8 +212,11 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
             }
         }
 
-        class ScopeRegistrationFinder : IXamlIlAstTransformer
+        class ScopeRegistrationFinder : IXamlIlAstVisitor
         {
+            private Stack<IXamlIlAstNode> _stack = new Stack<IXamlIlAstNode>();
+            private Stack<IXamlIlAstNode> _childScopesStack = new Stack<IXamlIlAstNode>();
+
             private ScopeRegistrationFinder(string name)
             {
                 Name = name;
@@ -210,16 +226,34 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
 
             IXamlIlType ControlType { get; set; }
 
-            public static IXamlIlType GetControlType(XamlIlAstTransformationContext context, IXamlIlAstNode namescopeRoot, string name)
+            public static IXamlIlType GetControlType(IXamlIlAstNode namescopeRoot, string name)
             {
                 var finder = new ScopeRegistrationFinder(name);
-                context.Visit(namescopeRoot, finder);
+                namescopeRoot.Visit(finder);
                 return finder.ControlType;
             }
 
-            IXamlIlAstNode IXamlIlAstTransformer.Transform(XamlIlAstTransformationContext context, IXamlIlAstNode node)
+            void IXamlIlAstVisitor.Pop()
+            {
+                var node = _stack.Pop();
+                if (_childScopesStack.Count > 0 && node == _childScopesStack.Peek())
+                {
+                    _childScopesStack.Pop();
+                }
+            }
+
+            void IXamlIlAstVisitor.Push(IXamlIlAstNode node)
+            {
+                _stack.Push(node);
+                if (node is NestedScopeMetadataNode)
+                {
+                    _childScopesStack.Push(node);
+                }
+            }
+
+            IXamlIlAstNode IXamlIlAstVisitor.Visit(IXamlIlAstNode node)
             {
-                if (node is ScopeRegistrationNode registration)
+                if (_childScopesStack.Count == 0 && node is ScopeRegistrationNode registration)
                 {
                     if (registration.Value is XamlIlAstTextNode text && text.Text == Name)
                     {