[XamlG] creates fields for x:Name on root

- fixes #2574

Xamarin.Forms.Build.Tasks/SetFieldVisitor.cs

@@ -30,16 +30,12 @@ public void Visit(ValueNode node, INode parentNode)
 		{
 			if (!IsXNameProperty(node, parentNode))
 				return;
-			if (!(parentNode is RootNode))
-			{
-				//no variable assigned for root 
-				var field = Context.Body.Method.DeclaringType.Fields.SingleOrDefault(fd => fd.Name == (string)node.Value);
-				if (field == null)
-					return;
-				Context.IL.Emit(OpCodes.Ldarg_0);
-				Context.IL.Emit(OpCodes.Ldloc, Context.Variables[(IElementNode)parentNode]);
-				Context.IL.Emit(OpCodes.Stfld, field);
-			}
+			var field = Context.Body.Method.DeclaringType.Fields.SingleOrDefault(fd => fd.Name == (string)node.Value);
+			if (field == null)
+				return;
+			Context.IL.Emit(OpCodes.Ldarg_0);
+			Context.IL.Emit(OpCodes.Ldloc, Context.Variables[(IElementNode)parentNode]);
+			Context.IL.Emit(OpCodes.Stfld, field);
 		}
 
 		public void Visit(MarkupNode node, INode parentNode)

Xamarin.Forms.Build.Tasks/XamlGenerator.cs

@@ -250,12 +250,9 @@ static IEnumerable<CodeMemberField> GetCodeMemberFields(XmlNode root, XmlNamespa
 
 			XmlNodeList names =
 				root.SelectNodes(
-				"//*[@" + xPrefix + ":Name" +
+					"//*[@" + xPrefix + ":Name" +
 					"][not(ancestor:: __f__:DataTemplate) and not(ancestor:: __f__:ControlTemplate) and not(ancestor:: __f__:Style) and not(ancestor:: __f__:VisualStateManager.VisualStateGroups)]", nsmgr);
 			foreach (XmlNode node in names) {
-				// Don't take the root canvas
-				if (node == root)
-					continue;
 				var name = GetAttributeValue(node, "Name", XamlParser.X2006Uri, XamlParser.X2009Uri);
 				var typeArguments = GetAttributeValue(node, "TypeArguments", XamlParser.X2006Uri, XamlParser.X2009Uri);
 				var fieldModifier = GetAttributeValue(node, "FieldModifier", XamlParser.X2006Uri, XamlParser.X2009Uri);

Xamarin.Forms.Xaml.UnitTests/Issues/Gh2574.xaml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    x:Class="Xamarin.Forms.Xaml.UnitTests.Gh2574"
+    x:Name="page">
+	<ContentPage.Content>
+	</ContentPage.Content>
+</ContentPage>

Xamarin.Forms.Xaml.UnitTests/Issues/Gh2574.xaml.cs

@@ -0,0 +1,42 @@
+using NUnit.Framework;
+using Xamarin.Forms.Core.UnitTests;
+
+namespace Xamarin.Forms.Xaml.UnitTests
+{
+	public partial class Gh2574 : ContentPage
+	{
+		public Gh2574()
+		{
+			InitializeComponent();
+		}
+
+		public Gh2574(bool useCompiledXaml)
+		{
+			//this stub will be replaced at compile time
+		}
+
+		[TestFixture]
+		class Tests
+		{
+
+			[SetUp]
+			public void Setup()
+			{
+				Device.PlatformServices = new MockPlatformServices();
+			}
+
+			[TearDown]
+			public void TearDown()
+			{
+				Device.PlatformServices = null;
+			}
+
+			[TestCase(false),TestCase(true)]
+			public void xNameOnRoot(bool useCompiledXaml)
+			{
+				var layout = new Gh2574(useCompiledXaml);
+				Assert.That(layout.page, Is.EqualTo(layout));
+			}
+		}
+	}
+}

Xamarin.Forms.Xaml.UnitTests/Xamarin.Forms.Xaml.UnitTests.csproj

@@ -609,6 +609,9 @@
     <Compile Include="Issues\Gh2549.xaml.cs">
       <DependentUpon>Gh2549.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Issues\Gh2574.xaml.cs">
+      <DependentUpon>Gh2574.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
 
@@ -1109,6 +1112,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="Issues\Gh2574.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />

Xamarin.Forms.Xaml.UnitTests/XamlgTests.cs

@@ -308,5 +308,24 @@ public void FieldModifier()
 				Assert.That(generator.NamedFields.First(cmf => cmf.Name == "publicLabel").Attributes, Is.EqualTo(MemberAttributes.Public));
 			}
 		}
+
+		[Test]
+		//https://github.com/xamarin/Xamarin.Forms/issues/2574
+		public void xNameOnRoot()
+		{
+			var xaml = @"<ContentPage
+		xmlns=""http://xamarin.com/schemas/2014/forms""
+		xmlns:x=""http://schemas.microsoft.com/winfx/2009/xaml""
+		x:Class=""Foo""
+		x:Name=""bar"">
+	</ContentPage>";
+
+			var generator = new XamlGenerator();
+			generator.ParseXaml(new StringReader(xaml));
+
+			Assert.AreEqual(1, generator.NamedFields.Count());
+			Assert.AreEqual("bar", generator.NamedFields.First().Name);
+			Assert.AreEqual("Xamarin.Forms.ContentPage", generator.NamedFields.First().Type.BaseType);
+		}
 	}
 }