Fix Implicit parameter conversion from integer to byte fails with source generated XAML

src/Controls/src/SourceGen/NodeSGExtensions.cs

@@ -301,7 +301,7 @@ void reportDiagnostic()
 			if (string.IsNullOrEmpty(valueString))
 				return "default";
 			if (sbyte.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out var sbyteValue))
-				return SymbolDisplay.FormatPrimitive(sbyteValue, true, false);
+				return $"(sbyte){SymbolDisplay.FormatPrimitive(sbyteValue, true, false)}";
 			else
 				reportDiagnostic();
 		}
@@ -310,7 +310,7 @@ void reportDiagnostic()
 			if (string.IsNullOrEmpty(valueString))
 				return "default";
 			if (byte.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out var byteValue))
-				return SymbolDisplay.FormatPrimitive(byteValue, true, false);
+				return $"(byte){SymbolDisplay.FormatPrimitive(byteValue, true, false)}";
 			else
 				reportDiagnostic();
 		}
@@ -319,16 +319,16 @@ void reportDiagnostic()
 			if (string.IsNullOrEmpty(valueString))
 				return "default";
 			if (short.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out var shortValue))
-				return SymbolDisplay.FormatPrimitive(shortValue, true, false);
+				return $"(short){SymbolDisplay.FormatPrimitive(shortValue, true, false)}";
 			else
 				reportDiagnostic();
 		}
 		if (toType.SpecialType == SpecialType.System_UInt16)
 		{
 			if (string.IsNullOrEmpty(valueString))
 				return "default";
-			if (short.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out var ushortValue))
-				return SymbolDisplay.FormatPrimitive(ushortValue, true, false);
+			if (ushort.TryParse(valueString, NumberStyles.Number, CultureInfo.InvariantCulture, out var ushortValue))
+				return $"(ushort){SymbolDisplay.FormatPrimitive(ushortValue, true, false)}";
 			else
 				reportDiagnostic();
 		}

src/Controls/tests/SourceGen.UnitTests/InitializeComponent/NumericBindablePropertyPrimitives.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Linq;
+using Xunit;
+
+namespace Microsoft.Maui.Controls.SourceGen.UnitTests;
+
+public class NumericBindablePropertyPrimitives : SourceGenXamlInitializeComponentTestBase
+{
+	[Fact]
+	public void BindableProperty_PrimitiveSmallIntegers_EmitTypedCastsAndBoundaries()
+	{
+		var xaml =
+"""
+<?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:Test"
+	x:Class="Test.TestPage">
+	<VerticalStackLayout>
+		<local:NumericView SByteValue="-128" ByteValue="255" ShortValue="0" UShortValue="65535" />
+	</VerticalStackLayout>
+</ContentPage>
+""";
+
+		var code =
+"""
+using System;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+
+namespace Test;
+
+[XamlProcessing(XamlInflator.SourceGen)]
+public partial class TestPage : ContentPage
+{
+	public TestPage()
+	{
+		InitializeComponent();
+	}
+}
+
+public class NumericView : BindableObject
+{
+	public static readonly BindableProperty SByteValueProperty =
+		BindableProperty.Create(nameof(SByteValue), typeof(sbyte), typeof(NumericView), default(sbyte));
+
+	public static readonly BindableProperty ByteValueProperty =
+		BindableProperty.Create(nameof(ByteValue), typeof(byte), typeof(NumericView), default(byte));
+
+	public static readonly BindableProperty ShortValueProperty =
+		BindableProperty.Create(nameof(ShortValue), typeof(short), typeof(NumericView), default(short));
+
+	public static readonly BindableProperty UShortValueProperty =
+		BindableProperty.Create(nameof(UShortValue), typeof(ushort), typeof(NumericView), default(ushort));
+
+	public sbyte SByteValue
+	{
+		get => (sbyte)GetValue(SByteValueProperty);
+		set => SetValue(SByteValueProperty, value);
+	}
+
+	public byte ByteValue
+	{
+		get => (byte)GetValue(ByteValueProperty);
+		set => SetValue(ByteValueProperty, value);
+	}
+
+	public short ShortValue
+	{
+		get => (short)GetValue(ShortValueProperty);
+		set => SetValue(ShortValueProperty, value);
+	}
+
+	public ushort UShortValue
+	{
+		get => (ushort)GetValue(UShortValueProperty);
+		set => SetValue(UShortValueProperty, value);
+	}
+}
+""";
+
+		var (result, generated) = RunGenerator(xaml, code);
+
+		Assert.Empty(result.Diagnostics.Where(d => d.Severity == Microsoft.CodeAnalysis.DiagnosticSeverity.Error));
+		Assert.NotNull(generated);
+
+		Assert.Contains("(sbyte)-128", generated, StringComparison.Ordinal);
+		Assert.Contains("(byte)255", generated, StringComparison.Ordinal);
+		Assert.Contains("(short)0", generated, StringComparison.Ordinal);
+		Assert.Contains("(ushort)65535", generated, StringComparison.Ordinal);
+	}
+}

src/Controls/tests/Xaml.UnitTests/SetValue.xaml

@@ -87,7 +87,7 @@
 				<d:IgnorableElement />
 			</ContentView.Content>
 		</ContentView>
-		<local:MockViewWithValues x:Name="mockView0" AChar="!" AByte="2" ASByte="-12" AShort="-22" UShort="32" ADecimal="42" />
+		<local:MockViewWithValues x:Name="mockView0" AChar="!" AByte="2" ASByte="-12" AShort="-22" UShort="32" ADecimal="42" BPByte="150" />
 		<local:ViewWithEnums x:Name="enums" IntEnum="Foo" ByteEnum="Bar" />
 		<local:MockViewWithValues x:Name="implicit0">
 			<local:MockViewWithValues.BPBar>

src/Controls/tests/Xaml.UnitTests/SetValue.xaml.cs

@@ -65,6 +65,15 @@ public string BPBar
 		get { throw new NotImplementedException(); }
 		set { throw new NotImplementedException(); }
 	}
+
+	public static readonly BindableProperty BPByteProperty =
+		BindableProperty.Create("BPByte", typeof(byte), typeof(MockViewWithValues), (byte)255);
+
+	public byte BPByte
+	{
+		get => (byte)GetValue(BPByteProperty);
+		set => SetValue(BPByteProperty, value);
+	}
 }
 
 [TypeConverter(typeof(SV_FooTypeConveter))]
@@ -390,6 +399,15 @@ public string BPBar
 		get { throw new NotImplementedException(); }
 		set { throw new NotImplementedException(); }
 	}
+
+	public static readonly BindableProperty BPByteProperty =
+		BindableProperty.Create("BPByte", typeof(byte), typeof(MockViewWithValues), (byte)0);
+
+	public byte BPByte
+	{
+		get => (byte)GetValue(BPByteProperty);
+		set => SetValue(BPByteProperty, value);
+	}
 }
 
 [TypeConverter(typeof(SV_FooTypeConveter))]
@@ -550,6 +568,7 @@ internal void MorePrimitiveTypes(XamlInflator inflator)
 			Assert.Equal((short)-22, page.mockView0.AShort);
 			Assert.Equal((ushort)32, page.mockView0.UShort);
 			Assert.Equal((decimal)42, page.mockView0.ADecimal);
+			Assert.Equal((byte)150, page.mockView0.BPByte);
 		}
 
 		[Theory]