sourcegen for x:Reference

Author: StephaneDelcroix

src/Controls/src/SourceGen/KnownMarkups.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Xml;
 
@@ -428,4 +429,35 @@ static bool IsBindingContextBinding(IElementNode node)
 				&& propertyName.LocalName == "BindingContext";
 		}
 	}
+
+	internal static string ProvideValueForReferenceExtension(IElementNode markupNode, SourceGenContext context, out ITypeSymbol? returnType)
+	{
+		// should be possible to return the right value, as soon as we no longer use the namescope
+		returnType = context.Compilation.ObjectType;
+		if (!markupNode.Properties.TryGetValue(new XmlName("", "Name"), out INode refNameNode)
+			&& !markupNode.Properties.TryGetValue(new XmlName(null, "Name"), out refNameNode))
+			refNameNode = markupNode.CollectionItems[0];
+		var name = ((ValueNode)refNameNode).Value as string;
+
+		var node = markupNode;
+		var currentcontext = context;
+		while (currentcontext is not null && node is not null)
+		{
+			while (currentcontext is not null && !currentcontext.Scopes.ContainsKey(node))			
+				currentcontext = context.ParentContext;
+			if (currentcontext is null)
+				break;
+			var namescope= currentcontext.Scopes[node];
+			if (namescope.namesInScope != null && namescope.namesInScope.ContainsKey(name!))
+			{
+				returnType = namescope.namesInScope[name!].Type;
+				return $"{namescope.namesInScope[name!].Name}"; 
+			}
+			node = node.Parent as IElementNode;	
+		}
+
+		//TODO report diagnostic
+		context.ReportDiagnostic(Diagnostic.Create(Descriptors.XamlParserError, null, $"ReferenceExtension: Name '{name}' not found in any NameScope"));
+		return "null"; // or throw an exception?
+	}
 }

src/Controls/src/SourceGen/NodeSGExtensions.cs

@@ -80,10 +80,11 @@ public static Dictionary<ITypeSymbol, ProvideValueDelegate> GetKnownEarlyMarkupE
 
     // These markup extensions can only provide values late once the properties have their final values
     public static Dictionary<ITypeSymbol, ProvideValueDelegate> GetKnownLateMarkupExtensions(SourceGenContext context)
-        => KnownSGLateMarkupExtensions ??= new (SymbolEqualityComparer.Default)
-    {
-        {context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.Xaml.BindingExtension")!, KnownMarkups.ProvideValueForBindingExtension},
-        {context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.Xaml.TemplateBindingExtension")!, KnownMarkups.ProvideValueForTemplateBindingExtension},
+        => KnownSGLateMarkupExtensions ??= new(SymbolEqualityComparer.Default)
+	{
+		{context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.Xaml.BindingExtension")!, KnownMarkups.ProvideValueForBindingExtension},
+		{context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.Xaml.TemplateBindingExtension")!, KnownMarkups.ProvideValueForTemplateBindingExtension},
+		{context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.Xaml.ReferenceExtension")!, KnownMarkups.ProvideValueForReferenceExtension},
     };
 
     public static bool TryGetPropertyName(this INode node, INode parentNode, out XmlName name)

src/Controls/src/SourceGen/SourceGenContext.cs

@@ -22,7 +22,7 @@ class SourceGenContext (IndentedTextWriter writer, Compilation compilation, Sour
     public void ReportDiagnostic(Diagnostic diagnostic) => sourceProductionContext.ReportDiagnostic(diagnostic);
     public string? FilePath {get; set;}
 	public IDictionary<INode, LocalVariable> ServiceProviders { get; } = new Dictionary<INode, LocalVariable>();
-	public IDictionary<INode, (LocalVariable namescope, IList<string> namesInScope)> Scopes = new Dictionary<INode, (LocalVariable, IList<string>)>(); 
+	public IDictionary<INode, (LocalVariable namescope, IDictionary<string, LocalVariable> namesInScope)> Scopes = new Dictionary<INode, (LocalVariable, IDictionary<string,LocalVariable>)>(); 
     public SourceGenContext? ParentContext {get;set;}
 	public ITypeSymbol? BaseType { get; } = baseType;
 	public IDictionary<INode, ITypeSymbol> Types { get; } = new Dictionary<INode, ITypeSymbol>();

src/Controls/src/SourceGen/Visitors/SetNamescopesAndRegisterNames.cs

@@ -27,10 +27,10 @@ public void Visit(ValueNode node, INode parentNode)
 		if (!IsXNameProperty(node, parentNode))
 			return;
         var name = (string)node.Value;
-        if (namescope.namesInScope.Contains(name))
+        if (namescope.namesInScope.ContainsKey(name))
             //TODO send diagnostic instead
             throw new Exception("dup x:Name");
-		namescope.namesInScope.Add(name);
+		namescope.namesInScope.Add(name,Context.Variables[(IElementNode)parentNode]);
         Writer.WriteLine($"{namescope.namescope.Name}.RegisterName(\"{name}\", {Context.Variables[(IElementNode)parentNode].Name});");
 
 		SetStyleId((string)node.Value, Context.Variables[(IElementNode)parentNode]);
@@ -42,13 +42,13 @@ public void Visit(MarkupNode node, INode parentNode)
 	public void Visit(ElementNode node, INode parentNode)
 	{
 		LocalVariable namescope;
-		IList<string> namesInNamescope;
+		IDictionary<string,LocalVariable> namesInNamescope;
 		var setNameScope = false;
 
 		if (parentNode == null || IsDataTemplate(node, parentNode) || IsStyle(node, parentNode) || IsVisualStateGroupList(node))
 		{
 			namescope = CreateNamescope();
-			namesInNamescope = [];
+			namesInNamescope = new Dictionary<string, LocalVariable>();
 			setNameScope = true;
 		}
 		else
@@ -71,7 +71,7 @@ public void Visit(RootNode node, INode parentNode)
 		if (Context.RootType.InheritsFrom(Context.Compilation.GetTypeByMetadataName("Microsoft.Maui.Controls.BindableObject")!, Context))
 			Writer.WriteLine($"global::Microsoft.Maui.Controls.Internals.NameScope.SetNameScope({Context.Variables[node].Name}, {namescope.Name});");
 
-		Context.Scopes[node] = new (namescope, []);
+		Context.Scopes[node] = new (namescope, new Dictionary<string, LocalVariable>());
 	}
 
 	public void Visit(ListNode node, INode parentNode)

src/Controls/src/Xaml/MarkupExtensions/ReferenceExtension.cs

@@ -1,7 +1,6 @@
 using System;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Maui.Controls.Internals;
-using Microsoft.Maui.Controls.Xaml.Internals;
 
 namespace Microsoft.Maui.Controls.Xaml
 {
@@ -22,12 +21,13 @@ public object ProvideValue(IServiceProvider serviceProvider)
 
 			//fallback
 			var valueProvider = serviceProvider.GetService<IProvideValueTarget>() as IProvideParentValues
-								   ?? throw new ArgumentException("serviceProvider does not provide an IProvideValueTarget");
+				?? throw new ArgumentException("serviceProvider does not provide an IProvideValueTarget");
+
 			foreach (var target in valueProvider.ParentObjects)
 			{
-				if (!(target is BindableObject bo))
+				if (target is not BindableObject bo)
 					continue;
-				if (!(NameScope.GetNameScope(bo) is INameScope ns))
+				if (NameScope.GetNameScope(bo) is not INameScope ns)
 					continue;
 				value = ns.FindByName(Name);
 				if (value != null)

src/Controls/src/Xaml/XamlProcessingAttribute.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.Versioning;
 
 namespace Microsoft.Maui.Controls.Xaml;
 

src/Controls/src/Xaml/XamlServiceProvider.cs

@@ -152,7 +152,7 @@ public class SimpleValueTargetProvider : IProvideParentValues, IProvideValueTarg
 		[Obsolete("Use the other ctor")]
 		//used by XamlC
 		public SimpleValueTargetProvider(object[] objectAndParents, object targetProperty, INameScope scope)
-			: this(objectAndParents, targetProperty, new INameScope[] { scope }, false)
+			: this(objectAndParents, targetProperty, [scope], false)
 		{
 		}
 

src/Controls/tests/Xaml.UnitTests/Issues/Gh2007.xaml.cs

@@ -2,7 +2,7 @@
 
 namespace Microsoft.Maui.Controls.Xaml.UnitTests;
 
-[XamlProcessing(XamlInflator.Default, true)]
+[XamlProcessing(XamlInflator.Runtime|XamlInflator.XamlC, true)]
 public partial class Gh2007 : ContentPage
 {
 	public Gh2007() => InitializeComponent();
@@ -15,11 +15,13 @@ public void UsefullxResourceErrorMessages([Values] XamlInflator inflator)
 		{
 			if (inflator == XamlInflator.Runtime || inflator == XamlInflator.XamlC)
 				Assert.Throws<XamlParseException>(() => new Gh2007(inflator));
-			if (inflator == XamlInflator.SourceGen)
+			else if (inflator == XamlInflator.SourceGen)
 			{
 				var result = MockSourceGenerator.RunMauiSourceGenerator(MockSourceGenerator.CreateMauiCompilation(), typeof(Gh2007));
 				Assert.That(result.Diagnostics, Is.Not.Empty);
 			}
+			else
+				Assert.Ignore("ignoring test for {inflator} as it is not supported in this context");
 		}
 	}
 }