[XSG] Fix MAUIX2003 error for x:Arguments with interface parameters

src/Controls/src/SourceGen/IMethodSymbolExtensions.cs

@@ -39,16 +39,23 @@ public static bool MatchXArguments(this IMethodSymbol method, ElementNode enode,
 			// }
 
 			var argType = getNodeValue?.Invoke(nodeparameters[i], paramType)?.Type ?? context.Variables[nodeparameters[i]].Type;
-			if (!argType.InheritsFrom(paramType, context))
+
+			// Check interface implementation first (interfaces don't use inheritance)
+			if (paramType.IsInterface())
 			{
-				parameters = null;
-				return false;
+				if (!argType.Implements(paramType))
+				{
+					parameters = null;
+					return false;
+				}
 			}
-			if (paramType.IsInterface() && !argType.Implements(paramType))
+			// Then check class inheritance
+			else if (!argType.InheritsFrom(paramType, context))
 			{
 				parameters = null;
 				return false;
 			}
+
 			parameters.Add((nodeparameters[i], paramType, null));
 		}
 		return true;

src/Controls/tests/Xaml.UnitTests/Issues/Maui32764.xaml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+			xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+			xmlns:local="clr-namespace:Microsoft.Maui.Controls.Xaml.UnitTests"
+			x:Class="Microsoft.Maui.Controls.Xaml.UnitTests.Maui32764">
+	<local:TestCarouselView x:Name="carouselView">
+		<x:Arguments>
+			<local:TestProcessor ScaleFactor="0.5" />
+		</x:Arguments>
+	</local:TestCarouselView>
+</ContentPage>

src/Controls/tests/Xaml.UnitTests/Issues/Maui32764.xaml.cs

@@ -0,0 +1,62 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+using System;
+using NUnit.Framework;
+
+namespace Microsoft.Maui.Controls.Xaml.UnitTests;
+
+// Simulate third-party control pattern (like CardView.MAUI) where constructors use interface parameters
+public interface ITestProcessor
+{
+}
+
+public class TestProcessor : ITestProcessor
+{
+	public double ScaleFactor { get; set; }
+}
+
+public class TestCardsView : ContentView
+{
+	public TestCardsView(ITestProcessor processor)
+	{
+		// Constructor that takes interface parameter
+	}
+}
+
+public class TestCarouselView : TestCardsView
+{
+	// Parameterless constructor chains to constructor with interface parameter
+	public TestCarouselView() : this(new TestProcessor())
+	{
+	}
+
+	// Constructor with interface parameter that chains to base
+	public TestCarouselView(ITestProcessor processor) : base(processor)
+	{
+	}
+}
+
+public partial class Maui32764 : ContentPage
+{
+	public Maui32764() => InitializeComponent();
+
+	[TestFixture]
+	class Tests
+	{
+		[Test]
+		public void XArgumentsWithInterfaceParameterShouldWork([Values] XamlInflator inflator)
+		{
+			// This test reproduces issue #32764
+			// The bug was that MatchXArguments incorrectly checked class inheritance
+			// before interface implementation, causing it to fail to match constructors
+			// with interface parameters when using x:Arguments in XAML
+			var page = new Maui32764(inflator);
+
+			// Just verifying the page loads without throwing is sufficient
+			// The original bug would throw MAUIX2003: "No method found for 'TestCarouselView'"
+			// because the source generator couldn't match the constructor taking ITestProcessor
+			Assert.That(page, Is.Not.Null);
+			Assert.That(page.carouselView, Is.Not.Null);
+		}
+	}
+}