Updated XamlIl. Now even more static typing

src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj

@@ -63,7 +63,6 @@
         <Compile Include="XamlIl\CompilerExtensions\Transformers\AvaloniaXamlIlTransformInstanceAttachedProperties.cs" />
         <Compile Include="XamlIl\CompilerExtensions\Transformers\AvaloniaXamlIlTransitionsTypeMetadataTransformer.cs" />
         <Compile Include="XamlIl\CompilerExtensions\Transformers\AvaloniaXamlIlWellKnownTypes.cs" />
-        <Compile Include="XamlIl\CompilerExtensions\Transformers\AvaloniaXamlIlBindingPropertyAssignmentsTransformer.cs" />
         <Compile Include="XamlIl\CompilerExtensions\XamlIlAvaloniaPropertyHelper.cs" />
         <Compile Include="XamlIl\CompilerExtensions\AvaloniaXamlIlCompiler.cs" />
         <Compile Include="XamlIl\CompilerExtensions\AvaloniaXamlIlLanguage.cs" />

src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/BindingExtension.cs

@@ -33,7 +33,7 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
             return ProvideTypedValue(serviceProvider);
         }
         
-        public IBinding ProvideTypedValue(IServiceProvider serviceProvider)
+        public Binding ProvideTypedValue(IServiceProvider serviceProvider)
         {
             var descriptorContext = (ITypeDescriptorContext)serviceProvider;
 

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

@@ -39,10 +39,9 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
             InsertBefore<XamlIlPropertyReferenceResolver>(new AvaloniaXamlIlTransformInstanceAttachedProperties());
             InsertAfter<XamlIlPropertyReferenceResolver>(new AvaloniaXamlIlAvaloniaPropertyResolver());
             
-            InsertBefore<XamlIlXamlPropertyValueTransformer>(new AvaloniaXamlIlBindingPropertyAssignmentsTransformer());
 
 
-            InsertBefore<XamlIlNewObjectTransformer>(
+            InsertBefore<XamlIlContentConvertTransformer>(
                 new AvaloniaXamlIlSelectorTransformer(),
                 new AvaloniaXamlIlSetterTransformer(),
                 new AvaloniaXamlIlControlTemplateTargetTypeMetadataTransformer(),

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

@@ -50,24 +50,8 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
                     typeSystem.GetType("Portable.Xaml.Markup.UsableDuringInitializationAttribute"),
                     typeSystem.GetType("Avalonia.Metadata.UsableDuringInitializationAttribute"),
                 },
-                MarkupExtensionCustomResultTypes =
-                {
-                    bindingType,
-                    typeSystem.GetType("Avalonia.UnsetValueType")
-                },
-                MarkupExtensionCustomResultHandler =
-                    runtimeHelpers.FindMethod(m => m.Name == "ApplyNonMatchingMarkupExtensionV1"),
                 InnerServiceProviderFactoryMethod =
                     runtimeHelpers.FindMethod(m => m.Name == "CreateInnerServiceProviderV1"),
-                ShouldIgnoreMarkupExtensionCustomResultForProperty = (prop, customType) =>
-                {
-                    if (prop.Name == "Value" && prop.Setter?.DeclaringType.FullName == "Avalonia.Styling.Setter")
-                        return true;
-                    if (customType.Equals(bindingType) &&
-                        prop.CustomAttributes.Any(a => a.Type.Equals(assignBindingAttribute)))
-                        return true;
-                    return false;
-                },
                 ProvideValueTargetPropertyEmitter = XamlIlAvaloniaPropertyHelper.Emit,
             };
             rv.CustomAttributeResolver = new AttributeResolver(typeSystem, rv);

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

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using XamlIl.Ast;
 using XamlIl.Transform;
 using XamlIl.TypeSystem;
@@ -11,21 +12,50 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
         {
             if (node is XamlIlPropertyAssignmentNode pa
                 && pa.Property.Name == "Name"
-                && pa.Property.Setter.DeclaringType.FullName == "Avalonia.StyledElement")
-                return new ScopeRegistrationNode(pa);
+                && 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))
+                        {
+                            var local = new XamlIlAstCompilerLocalNode(value);
+                            // Wrap original in local initialization
+                            pa.Values[c] = new XamlIlAstLocalInitializationNodeEmitter(value, value, local);
+                            // Use local
+                            value = local;
+                        }
+
+                        break;
+                    }
+
+                if (value != null)
+                    return new XamlIlManipulationGroupNode(pa)
+                    {
+                        Children =
+                        {
+                            pa,
+                            new ScopeRegistrationNode(value)
+                        }
+                    };
+            }
 
             return node;
         }
 
         class ScopeRegistrationNode : XamlIlAstNode, IXamlIlAstManipulationNode, IXamlIlAstEmitableNode
         {
+            private readonly IXamlIlType _targetType;
             public IXamlIlAstValueNode Value { get; set; }
-            private IXamlIlProperty _property;
-
-            public ScopeRegistrationNode(XamlIlPropertyAssignmentNode pa) : base(pa)
+            public ScopeRegistrationNode(IXamlIlAstValueNode value) : base(value)
             {
-                _property = pa.Property;
-                Value = pa.Value;
+                Value = value;
             }
 
             public override void VisitChildren(IXamlIlAstVisitor visitor)
@@ -36,24 +66,13 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 var exts = context.Configuration.TypeSystem.GetType("Avalonia.Controls.NameScopeExtensions");
                 var findNameScope = exts.FindMethod(m => m.Name == "FindNameScope");
                 var registerMethod = findNameScope.ReturnType.FindMethod(m => m.Name == "Register");
-                using (var nameLoc = context.GetLocal(context.Configuration.WellKnownTypes.String))
-                using (var targetLoc = context.GetLocal(_property.Setter.DeclaringType))
+                using (var targetLoc = context.GetLocal(context.Configuration.WellKnownTypes.Object))
                 using (var nameScopeLoc = context.GetLocal(findNameScope.ReturnType))
                 {
                     var exit = codeGen.DefineLabel();
-
-                    // var target = {target}
                     codeGen
-                        .Castclass(_property.Setter.DeclaringType)
-                        .Stloc(targetLoc.Local);
-                    
-                    // var name = {EmitName()}
-                    context.Emit(Value, codeGen, _property.PropertyType);
-                    codeGen.Stloc(nameLoc.Local)
-                        // target.Name = name
-                        .Ldloc(targetLoc.Local)
-                        .Ldloc(nameLoc.Local)
-                        .EmitCall(_property.Setter)
+                        // var target = {pop}    
+                        .Stloc(targetLoc.Local)
                         // var scope = target.FindNameScope()
                         .Ldloc(targetLoc.Local)
                         .Castclass(findNameScope.Parameters[0])
@@ -62,8 +81,9 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                         // if({scope} != null) goto call;
                         .Ldloc(nameScopeLoc.Local)
                         .Brfalse(exit)
-                        .Ldloc(nameScopeLoc.Local)
-                        .Ldloc(nameLoc.Local)
+                        .Ldloc(nameScopeLoc.Local);
+                    context.Emit(Value, codeGen, Value.Type.GetClrType());
+                    codeGen
                         .Ldloc(targetLoc.Local)
                         .EmitCall(registerMethod)
                         .MarkLabel(exit);

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

@@ -8,14 +8,14 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
     {
         public IXamlIlAstNode Transform(XamlIlAstTransformationContext context, IXamlIlAstNode node)
         {
-            if (node is XamlIlAstClrPropertyReference prop)
+            if (node is XamlIlAstClrProperty prop)
             {
-                var n = prop.Property.Name + "Property";
+                var n = prop.Name + "Property";
                 var field =
-                    (prop.Property.Getter ?? prop.Property.Setter).DeclaringType.Fields
+                    prop.DeclaringType.Fields
                     .FirstOrDefault(f => f.Name == n);
                 if (field != null)
-                    prop.Property = new XamlIlAvaloniaProperty(prop.Property, field);
+                    return new XamlIlAvaloniaProperty(prop, field, context.GetAvaloniaTypes());
             }
 
             return node;

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

@@ -1,114 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using XamlIl.Ast;
-using XamlIl.Transform;
-using XamlIl.TypeSystem;
-
-namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
-{
-    public class AvaloniaXamlIlBindingPropertyAssignmentsTransformer : IXamlIlAstTransformer
-    {
-        public IXamlIlAstNode Transform(XamlIlAstTransformationContext context, IXamlIlAstNode node)
-        {
-            if (node is XamlIlAstXamlPropertyValueNode pv 
-                && pv.Property.GetClrProperty() is IXamlIlAvaloniaProperty ap
-                && pv.Values.Count == 1)
-            {
-                var types = context.GetAvaloniaTypes();
-                
-                var vn = pv.Values[0];
-                if (vn.Type.GetClrType().Equals(XamlIlPseudoType.Null))
-                    return node;
-
-                if (pv.Property.GetClrProperty().CustomAttributes
-                    .Any(a => a.Type.Equals(types.AssignBindingAttribute)))
-                    return node;
-                
-                // Special handling for markup extensions
-                if (vn.Type.IsMarkupExtension)
-                {
-                    if (XamlIlTransformHelpers
-                        .GetMarkupExtensionProvideValueAlternatives(context, vn.Type.GetClrType())
-                        .Any(x => types.IBinding.IsAssignableFrom(x.ReturnType)))
-                    {
-                        if (XamlIlTransformHelpers.TryConvertMarkupExtension(context, pv.Values[0],
-                            new AssignBindingProperty(types, ap), out var ext))
-                            return ext;
-                    }
-                }
-                else if (types.IBinding.IsAssignableFrom(vn.Type.GetClrType()))
-                {
-                    pv.Property = new XamlIlAstClrPropertyReference(pv.Property, new AssignBindingProperty(types, ap));
-                }
-            }
-
-            return node;
-        }
-
-        class AssignBindingProperty : IXamlIlAvaloniaProperty
-        {
-            public AssignBindingProperty(
-                AvaloniaXamlIlWellKnownTypes types,
-                IXamlIlAvaloniaProperty property
-                )
-            {
-                PropertyType = types.IBinding;
-                AvaloniaProperty = property.AvaloniaProperty;
-                CustomAttributes = property.CustomAttributes;
-                Name = property.Name;
-                Setter = new SetterMethod(types, (property.Setter ?? property.Getter).DeclaringType,
-                    AvaloniaProperty);
-            }
-
-            public bool Equals(IXamlIlProperty other) =>
-                other is AssignBindingProperty abp && abp.AvaloniaProperty.Equals(AvaloniaProperty);
-
-            public string Name { get; }
-            public IXamlIlType PropertyType { get; }
-            public IXamlIlMethod Setter { get; }
-            public IXamlIlMethod Getter { get; }
-            public IReadOnlyList<IXamlIlCustomAttribute> CustomAttributes { get; }
-            public IXamlIlField AvaloniaProperty { get; }
-
-            class SetterMethod : IXamlIlCustomEmitMethod
-            {
-                private readonly AvaloniaXamlIlWellKnownTypes _types;
-                private readonly IXamlIlField _avaloniaProperty;
-
-                public SetterMethod(AvaloniaXamlIlWellKnownTypes types,
-                    IXamlIlType declaringType,
-                    IXamlIlField avaloniaProperty)
-                {
-                    _types = types;
-                    _avaloniaProperty = avaloniaProperty;
-                    Parameters = new[] {types.AvaloniaObject, types.IBinding};
-                    ReturnType = types.XamlIlTypes.Void;
-                    DeclaringType = declaringType;
-                    Name = "Bind_" + avaloniaProperty.Name;
-                }
-
-                public bool Equals(IXamlIlMethod other) =>
-                    other is SetterMethod sm && sm._avaloniaProperty.Equals(_avaloniaProperty); 
-
-                public string Name { get; }
-                public bool IsPublic => true;
-                public bool IsStatic => true;
-                public IXamlIlType ReturnType { get; }
-                public IReadOnlyList<IXamlIlType> Parameters { get; }
-                public IXamlIlType DeclaringType { get; }
-                public void EmitCall(IXamlIlEmitter emitter)
-                {
-                    using (var bloc = emitter.LocalsPool.GetLocal(_types.IBinding))
-                        emitter
-                            .Stloc(bloc.Local)
-                            .Ldsfld(_avaloniaProperty)
-                            .Ldloc(bloc.Local)
-                            // TODO: provide anchor?
-                            .Ldnull();
-                    emitter.EmitCall(_types.AvaloniaObjectBindMethod, true);
-                }
-            }
-        }
-    }
-}

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

@@ -34,7 +34,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             if (!(pn.Values[0] is XamlIlAstTextNode tn))
                 throw new XamlIlParseException("Selector property should be a text node", node);
 
-            var selectorType = pn.Property.GetClrProperty().PropertyType;
+            var selectorType = pn.Property.GetClrProperty().Getter.ReturnType;
             var initialNode = new XamlIlSelectorInitialNode(node, selectorType);
             XamlIlSelectorNode Create(IEnumerable<SelectorGrammar.ISyntax> syntax,
                 Func<string, string, XamlIlAstClrTypeReference> typeResolver)

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

@@ -53,21 +53,56 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 .OfType<XamlIlAstXamlPropertyValueNode>().FirstOrDefault(p => p.Property.GetClrProperty().Name == "Value");
             if (valueProperty?.Values?.Count == 1 && valueProperty.Values[0] is XamlIlAstTextNode)
             {
+                var propType = avaloniaPropertyNode.Property.Getter?.ReturnType
+                               ?? avaloniaPropertyNode.Property.Setters.First().Parameters[0];
                 if (!XamlIlTransformHelpers.TryGetCorrectlyTypedValue(context, valueProperty.Values[0],
-                        avaloniaPropertyNode.Property.PropertyType, out var converted))
+                        propType, out var converted))
                     throw new XamlIlParseException(
-                        $"Unable to convert property value to {avaloniaPropertyNode.Property.PropertyType.GetFqn()}",
+                        $"Unable to convert property value to {propType.GetFqn()}",
                         valueProperty.Values[0]);
 
-                valueProperty.Values = new List<IXamlIlAstValueNode>
-                {
-                    new XamlIlAstRuntimeCastNode(converted, converted,
-                        new XamlIlAstClrTypeReference(converted, context.Configuration.WellKnownTypes.Object, false))
-                };
+                valueProperty.Property = new SetterValueProperty(valueProperty.Property,
+                    on.Type.GetClrType(), propType, context.GetAvaloniaTypes());
             }
 
             return node;
         }
-        
+
+        class SetterValueProperty : XamlIlAstClrProperty
+        {
+            public SetterValueProperty(IXamlIlLineInfo line, IXamlIlType setterType, IXamlIlType targetType,
+                AvaloniaXamlIlWellKnownTypes types)
+                : base(line, "Value", setterType, null)
+            {
+                Getter = setterType.Methods.First(m => m.Name == "get_Value");
+                var method = setterType.Methods.First(m => m.Name == "set_Value");
+                Setters.Add(new XamlIlDirectCallPropertySetter(method, types.IBinding));
+                Setters.Add(new XamlIlDirectCallPropertySetter(method, types.UnsetValueType));
+                Setters.Add(new XamlIlDirectCallPropertySetter(method, targetType));
+            }
+            
+            class XamlIlDirectCallPropertySetter : IXamlIlPropertySetter
+            {
+                private readonly IXamlIlMethod _method;
+                private readonly IXamlIlType _type;
+                public IXamlIlType TargetType { get; }
+                public PropertySetterBinderParameters BinderParameters { get; } = new PropertySetterBinderParameters();
+                public IReadOnlyList<IXamlIlType> Parameters { get; }
+                public void Emit(IXamlIlEmitter codegen)
+                {
+                    if (_type.IsValueType)
+                        codegen.Box(_type);
+                    codegen.EmitCall(_method, true);
+                }
+
+                public XamlIlDirectCallPropertySetter(IXamlIlMethod method, IXamlIlType type)
+                {
+                    _method = method;
+                    _type = type;
+                    Parameters = new[] {type};
+                    TargetType = method.ThisOrFirstParameter();
+                }
+            }
+        }
     }
 }

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

@@ -56,10 +56,9 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                                 avaloniaPropertyType.GenericArguments[0] :
                                 context.Configuration.WellKnownTypes.Object;
 
-                            return new XamlIlAstClrPropertyReference(prop,
-                                new AvaloniaAttachedInstanceProperty(prop.Name, context.Configuration,
+                            return new AvaloniaAttachedInstanceProperty(prop, context.Configuration,
                                     declaringType, propertyType, avaloniaPropertyType, avaloniaObject,
-                                    avaloniaPropertyField));
+                                    avaloniaPropertyField);
                         }
 
                     }
@@ -71,7 +70,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             return node;
         }
 
-        class AvaloniaAttachedInstanceProperty : IXamlIlAvaloniaProperty
+        class AvaloniaAttachedInstanceProperty : XamlIlAstClrProperty, IXamlIlAvaloniaProperty
         {
             private readonly XamlIlTransformerConfiguration _config;
             private readonly IXamlIlType _declaringType;
@@ -79,13 +78,16 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             private readonly IXamlIlType _avaloniaObject;
             private readonly IXamlIlField _field;
 
-            public AvaloniaAttachedInstanceProperty(string name,
+            public AvaloniaAttachedInstanceProperty(XamlIlAstNamePropertyReference prop,
                 XamlIlTransformerConfiguration config,
                 IXamlIlType declaringType,
                 IXamlIlType type,
                 IXamlIlType avaloniaPropertyType,
                 IXamlIlType avaloniaObject,
-                IXamlIlField field)
+                IXamlIlField field) : base(prop, prop.Name,
+                declaringType, null)
+            
+            
             {
                 _config = config;
                 _declaringType = declaringType;
@@ -97,72 +99,50 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 
                 _avaloniaObject = avaloniaObject;
                 _field = field;
-                Name = name;
                 PropertyType = type;
-                Setter = new SetterMethod(this);
+                Setters.Add(new SetterMethod(this));
                 Getter = new GetterMethod(this);
             }
 
-            public IXamlIlField AvaloniaProperty => _field;
-            public bool Equals(IXamlIlProperty other) =>
-                other is AvaloniaAttachedInstanceProperty ap && ap._field.Equals(_field);
-
-            public string Name { get; }
-            public IXamlIlType PropertyType { get; }
-            public IXamlIlMethod Setter { get; }
-            public IXamlIlMethod Getter { get; }
-            public IReadOnlyList<IXamlIlCustomAttribute> CustomAttributes { get; } = new List<IXamlIlCustomAttribute>();
-
-            class Method
-            {
-                public AvaloniaAttachedInstanceProperty Parent { get; }
-                public bool IsPublic => true;
-                public bool IsStatic => true;
-                public string Name { get; protected set; }
-                public IXamlIlType DeclaringType { get; }
-                public Method(AvaloniaAttachedInstanceProperty parent)
-                {
-                    Parent = parent;
-                    DeclaringType = parent._declaringType;
-                }
+            public IXamlIlType PropertyType { get;  }
 
-                public bool Equals(IXamlIlMethod other) =>
-                    other is Method m && m.Name == Name && m.DeclaringType.Equals(DeclaringType);
-            }
+            public IXamlIlField AvaloniaProperty => _field;
             
-            class SetterMethod : Method, IXamlIlCustomEmitMethod
+            class SetterMethod : IXamlIlPropertySetter
             {
-                public SetterMethod(AvaloniaAttachedInstanceProperty parent) : base(parent)
+                private readonly AvaloniaAttachedInstanceProperty _parent;
+
+                public SetterMethod(AvaloniaAttachedInstanceProperty parent)
                 {
-                    Name = "AvaloniaObject:SetValue_" + Parent.Name;
-                    Parameters = new[] {Parent._avaloniaObject, Parent.PropertyType};
+                    _parent = parent;
+                    Parameters = new[] {_parent._avaloniaObject, _parent.PropertyType};
                 }
 
-                public IXamlIlType ReturnType => Parent._config.WellKnownTypes.Void;
+                public IXamlIlType TargetType => _parent.DeclaringType;
+                public PropertySetterBinderParameters BinderParameters { get; } = new PropertySetterBinderParameters();
                 public IReadOnlyList<IXamlIlType> Parameters { get; }
-                
-                public void EmitCall(IXamlIlEmitter emitter)
+                public void Emit(IXamlIlEmitter emitter)
                 {
-                    var so = Parent._config.WellKnownTypes.Object;
-                    var method = Parent._avaloniaObject
+                    var so = _parent._config.WellKnownTypes.Object;
+                    var method = _parent._avaloniaObject
                         .FindMethod(m => m.IsPublic && !m.IsStatic && m.Name == "SetValue"
                                          &&
                                          m.Parameters.Count == 3
-                                         && m.Parameters[0].Equals(Parent._avaloniaPropertyType)
+                                         && m.Parameters[0].Equals(_parent._avaloniaPropertyType)
                                          && m.Parameters[1].Equals(so)
                                          && m.Parameters[2].IsEnum
                         );
                     if (method == null)
                         throw new XamlIlTypeSystemException(
                             "Unable to find SetValue(AvaloniaProperty, object, BindingPriority) on AvaloniaObject");
-                    using (var loc = emitter.LocalsPool.GetLocal(Parent.PropertyType))
+                    using (var loc = emitter.LocalsPool.GetLocal(_parent.PropertyType))
                         emitter
                             .Stloc(loc.Local)
-                            .Ldsfld(Parent._field)
+                            .Ldsfld(_parent._field)
                             .Ldloc(loc.Local);
 
-                    if(Parent.PropertyType.IsValueType)
-                        emitter.Box(Parent.PropertyType);
+                    if(_parent.PropertyType.IsValueType)
+                        emitter.Box(_parent.PropertyType);
                     emitter        
                         .Ldc_I4(0)
                         .EmitCall(method);
@@ -170,14 +150,24 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 }
             }
 
-            class GetterMethod : Method, IXamlIlCustomEmitMethod
+            class GetterMethod :  IXamlIlCustomEmitMethod
             {
-                public GetterMethod(AvaloniaAttachedInstanceProperty parent) : base(parent)
+                public GetterMethod(AvaloniaAttachedInstanceProperty parent) 
                 {
+                    Parent = parent;
+                    DeclaringType = parent._declaringType;
                     Name = "AvaloniaObject:GetValue_" + Parent.Name;
                     Parameters = new[] {parent._avaloniaObject};
                 }
+                public AvaloniaAttachedInstanceProperty Parent { get; }
+                public bool IsPublic => true;
+                public bool IsStatic => true;
+                public string Name { get; protected set; }
+                public IXamlIlType DeclaringType { get; }
+
 
+                public bool Equals(IXamlIlMethod other) =>
+                    other is GetterMethod m && m.Name == Name && m.DeclaringType.Equals(DeclaringType);
                 public IXamlIlType ReturnType => Parent.PropertyType;
                 public IReadOnlyList<IXamlIlType> Parameters { get; }
                 public void EmitCall(IXamlIlEmitter emitter)

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

@@ -12,7 +12,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 foreach (var ch in on.Children)
                 {
                     if (ch is XamlIlAstXamlPropertyValueNode pn
-                        && pn.Property.GetClrProperty().PropertyType.Equals(context.GetAvaloniaTypes().Transitions))
+                        && pn.Property.GetClrProperty().Getter?.ReturnType.Equals(context.GetAvaloniaTypes().Transitions) == true)
                     {
                         for (var c = 0; c < pn.Values.Count; c++)
                         {

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

@@ -7,14 +7,17 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
     {
         public IXamlIlType AvaloniaObject { get; }
         public IXamlIlType IAvaloniaObject { get; }
+        public IXamlIlType BindingPriority { get; }
         public IXamlIlType AvaloniaObjectExtensions { get; }
         public IXamlIlType AvaloniaProperty { get; }
         public IXamlIlType IBinding { get; }
         public IXamlIlMethod AvaloniaObjectBindMethod { get; }
+        public IXamlIlMethod AvaloniaObjectSetValueMethod { get; }
         public IXamlIlType IDisposable { get; }
         public XamlIlTypeWellKnownTypes XamlIlTypes { get; }
         public IXamlIlType Transitions { get; }
         public IXamlIlType AssignBindingAttribute { get; }
+        public IXamlIlType UnsetValueType { get; }
         
         public AvaloniaXamlIlWellKnownTypes(XamlIlAstTransformationContext ctx)
         {
@@ -23,6 +26,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             IAvaloniaObject = ctx.Configuration.TypeSystem.GetType("Avalonia.IAvaloniaObject");
             AvaloniaObjectExtensions = ctx.Configuration.TypeSystem.GetType("Avalonia.AvaloniaObjectExtensions");
             AvaloniaProperty = ctx.Configuration.TypeSystem.GetType("Avalonia.AvaloniaProperty");
+            BindingPriority = ctx.Configuration.TypeSystem.GetType("Avalonia.Data.BindingPriority");
             IBinding = ctx.Configuration.TypeSystem.GetType("Avalonia.Data.IBinding");
             IDisposable = ctx.Configuration.TypeSystem.GetType("System.IDisposable");
             Transitions = ctx.Configuration.TypeSystem.GetType("Avalonia.Animation.Transitions");
@@ -30,6 +34,9 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             AvaloniaObjectBindMethod = AvaloniaObjectExtensions.FindMethod("Bind", IDisposable, false, IAvaloniaObject,
                 AvaloniaProperty,
                 IBinding, ctx.Configuration.WellKnownTypes.Object);
+            UnsetValueType = ctx.Configuration.TypeSystem.GetType("Avalonia.UnsetValueType");
+            AvaloniaObjectSetValueMethod = AvaloniaObject.FindMethod("SetValue", XamlIlTypes.Void,
+                false, AvaloniaProperty, XamlIlTypes.Object, BindingPriority);
         }
     }
 

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

@@ -1,7 +1,9 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Xml;
 using Avalonia.Markup.Xaml.Parsers;
+using Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers;
 using Avalonia.Utilities;
 using XamlIl;
 using XamlIl.Ast;
@@ -13,13 +15,25 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
 {
     class XamlIlAvaloniaPropertyHelper
     {
-        public static bool Emit(XamlIlEmitContext context, IXamlIlEmitter emitter, IXamlIlProperty property)
+        public static bool Emit(XamlIlEmitContext context, IXamlIlEmitter emitter, XamlIlAstClrProperty property)
         {
             if (property is IXamlIlAvaloniaProperty ap)
             {
                 emitter.Ldsfld(ap.AvaloniaProperty);
                 return true;
             }
+            var type = property.DeclaringType;
+            var name = property.Name + "Property";
+            var found = type.Fields.FirstOrDefault(f => f.IsStatic && f.Name == name);
+            if (found == null)
+                return false;
+
+            emitter.Ldsfld(found);
+            return true;
+        }
+        
+        public static bool Emit(XamlIlEmitContext context, IXamlIlEmitter emitter, IXamlIlProperty property)
+        {
             var type = (property.Getter ?? property.Setter).DeclaringType;
             var name = property.Name + "Property";
             var found = type.Fields.FirstOrDefault(f => f.IsStatic && f.Name == name);
@@ -54,8 +68,8 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
             }
 
             var clrProperty =
-                ((XamlIlAstClrPropertyReference)new XamlIlPropertyReferenceResolver().Transform(context,
-                    forgedReference)).Property;
+                ((XamlIlAstClrProperty)new XamlIlPropertyReferenceResolver().Transform(context,
+                    forgedReference));
             return new XamlIlAvaloniaPropertyNode(lineInfo,
                 context.Configuration.TypeSystem.GetType("Avalonia.AvaloniaProperty"),
                 clrProperty);
@@ -64,13 +78,13 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
     
     class XamlIlAvaloniaPropertyNode : XamlIlAstNode, IXamlIlAstValueNode, IXamlIlAstEmitableNode
     {
-        public XamlIlAvaloniaPropertyNode(IXamlIlLineInfo lineInfo, IXamlIlType type, IXamlIlProperty property) : base(lineInfo)
+        public XamlIlAvaloniaPropertyNode(IXamlIlLineInfo lineInfo, IXamlIlType type, XamlIlAstClrProperty property) : base(lineInfo)
         {
             Type = new XamlIlAstClrTypeReference(this, type, false);
             Property = property;
         }
 
-        public IXamlIlProperty Property { get; }
+        public XamlIlAstClrProperty Property { get; }
 
         public IXamlIlAstTypeReference Type { get; }
         public XamlIlNodeEmitResult Emit(XamlIlEmitContext context, IXamlIlEmitter codeGen)
@@ -81,29 +95,92 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions
         }
     }
 
-    interface IXamlIlAvaloniaProperty : IXamlIlProperty
+    interface IXamlIlAvaloniaProperty
     {
         IXamlIlField AvaloniaProperty { get; }
     }
     
-    class XamlIlAvaloniaProperty : IXamlIlAvaloniaProperty
+    class XamlIlAvaloniaProperty : XamlIlAstClrProperty, IXamlIlAvaloniaProperty
     {
-        private readonly IXamlIlProperty _original;
-
         public IXamlIlField AvaloniaProperty { get; }
-        public XamlIlAvaloniaProperty(IXamlIlProperty original, IXamlIlField field)
+        public XamlIlAvaloniaProperty(XamlIlAstClrProperty original, IXamlIlField field,
+            AvaloniaXamlIlWellKnownTypes types)
+            :base(original, original.Name, original.DeclaringType, original.Getter, original.Setters)
         {
-            _original = original;
             AvaloniaProperty = field;
+            CustomAttributes = original.CustomAttributes;
+            if (!original.CustomAttributes.Any(ca => ca.Type.Equals(types.AssignBindingAttribute)))
+                Setters.Insert(0, new BindingSetter(types, original.DeclaringType, field));
+            
+            Setters.Insert(0, new UnsetValueSetter(types, original.DeclaringType, field));
         }
 
-        public bool Equals(IXamlIlProperty other) =>
-            other is XamlIlAvaloniaProperty p && p.AvaloniaProperty.Equals(AvaloniaProperty);
+        abstract class AvaloniaPropertyCustomSetter : IXamlIlPropertySetter
+        {
+            protected AvaloniaXamlIlWellKnownTypes Types;
+            protected IXamlIlField AvaloniaProperty;
 
-        public string Name => _original.Name;
-        public IXamlIlType PropertyType => _original.PropertyType;
-        public IXamlIlMethod Setter => _original.Setter;
-        public IXamlIlMethod Getter => _original.Getter;
-        public IReadOnlyList<IXamlIlCustomAttribute> CustomAttributes => _original.CustomAttributes;
+            public AvaloniaPropertyCustomSetter(AvaloniaXamlIlWellKnownTypes types,
+                IXamlIlType declaringType,
+                IXamlIlField avaloniaProperty)
+            {
+                Types = types;
+                AvaloniaProperty = avaloniaProperty;
+                TargetType = declaringType;
+            }
+
+            public IXamlIlType TargetType { get; }
+
+            public PropertySetterBinderParameters BinderParameters { get; } = new PropertySetterBinderParameters
+            {
+                AllowNull = false
+            };
+
+            public IReadOnlyList<IXamlIlType> Parameters { get; set; }
+            public abstract void Emit(IXamlIlEmitter codegen);
+        }
+
+        class BindingSetter : AvaloniaPropertyCustomSetter
+        {
+            public BindingSetter(AvaloniaXamlIlWellKnownTypes types,
+                IXamlIlType declaringType,
+                IXamlIlField avaloniaProperty) : base(types, declaringType, avaloniaProperty)
+            {
+                Parameters = new[] {types.IBinding};
+            }
+
+            public override void Emit(IXamlIlEmitter emitter)
+            {
+                using (var bloc = emitter.LocalsPool.GetLocal(Types.IBinding))
+                    emitter
+                        .Stloc(bloc.Local)
+                        .Ldsfld(AvaloniaProperty)
+                        .Ldloc(bloc.Local)
+                        // TODO: provide anchor?
+                        .Ldnull();
+                emitter.EmitCall(Types.AvaloniaObjectBindMethod, true);
+            }
+        }
+
+        class UnsetValueSetter : AvaloniaPropertyCustomSetter
+        {
+            public UnsetValueSetter(AvaloniaXamlIlWellKnownTypes types, IXamlIlType declaringType, IXamlIlField avaloniaProperty) 
+                : base(types, declaringType, avaloniaProperty)
+            {
+                Parameters = new[] {types.UnsetValueType};
+            }
+
+            public override void Emit(IXamlIlEmitter codegen)
+            {
+                var unsetValue = Types.AvaloniaProperty.Fields.First(f => f.Name == "UnsetValue");
+                codegen
+                    // Ignore the instance and load one from the static field to avoid extra local variable
+                    .Pop()
+                    .Ldsfld(AvaloniaProperty)
+                    .Ldsfld(unsetValue)
+                    .Ldc_I4(0)
+                    .EmitCall(Types.AvaloniaObjectSetValueMethod, true);
+            }
+        }
     }
 }

src/Markup/Avalonia.Markup.Xaml/XamlIl/xamlil.github

@@ -1 +1 @@
-Subproject commit c0da3c49810316a96b47a00a83ae79d4f28406a1
+Subproject commit 56c401c48f51979201ad810c96a9644705d4ddd9