[Rgen] Keep track of properties/methods/ctrs that use smart enums.

src/rgen/Microsoft.Macios.Generator/DataModel/Constructor.cs

@@ -68,6 +68,7 @@ public static bool TryCreate (ConstructorDeclarationSyntax declaration, Semantic
 				IsParams = parameter.IsParams,
 				IsThis = parameter.IsThis,
 				IsNullable = parameter.NullableAnnotation == NullableAnnotation.Annotated,
+				IsSmartEnum = parameter.Type.IsSmartEnum (),
 				DefaultValue = (parameter.HasExplicitDefaultValue) ? parameter.ExplicitDefaultValue?.ToString () : null,
 				ReferenceKind = parameter.RefKind.ToReferenceKind (),
 				Attributes = parameterDeclaration.GetAttributeCodeChanges (semanticModel),

src/rgen/Microsoft.Macios.Generator/DataModel/Method.cs

@@ -81,6 +81,7 @@ public static bool TryCreate (MethodDeclarationSyntax declaration, SemanticModel
 				IsParams = parameter.IsParams,
 				IsThis = parameter.IsThis,
 				IsNullable = parameter.NullableAnnotation == NullableAnnotation.Annotated,
+				IsSmartEnum = parameter.Type.IsSmartEnum (),
 				DefaultValue = (parameter.HasExplicitDefaultValue) ? parameter.ExplicitDefaultValue?.ToString () : null,
 				ReferenceKind = parameter.RefKind.ToReferenceKind (),
 				Attributes = parameterDeclaration.GetAttributeCodeChanges (semanticModel),

src/rgen/Microsoft.Macios.Generator/DataModel/Parameter.cs

@@ -43,6 +43,11 @@ namespace Microsoft.Macios.Generator.DataModel;
 	/// </summary>
 	public bool IsNullable { get; init; }
 
+	/// <summary>
+	/// Returns if the parameter type is a smart enum.
+	/// </summary>
+	public bool IsSmartEnum { get; init; }
+
 	/// <summary>
 	/// Optional default value.
 	/// </summary>
@@ -82,6 +87,8 @@ public bool Equals (Parameter other)
 			return false;
 		if (IsNullable != other.IsNullable)
 			return false;
+		if (IsSmartEnum != other.IsSmartEnum)
+			return false;
 		if (DefaultValue != other.DefaultValue)
 			return false;
 		if (ReferenceKind != other.ReferenceKind)
@@ -107,6 +114,7 @@ public override int GetHashCode ()
 		hashCode.Add (IsParams);
 		hashCode.Add (IsThis);
 		hashCode.Add (IsNullable);
+		hashCode.Add (IsSmartEnum);
 		hashCode.Add (DefaultValue);
 		hashCode.Add ((int) ReferenceKind);
 		return hashCode.ToHashCode ();
@@ -135,6 +143,7 @@ public override string ToString ()
 		sb.Append ($"IsParams {IsParams}, ");
 		sb.Append ($"IsThis: {IsThis}, ");
 		sb.Append ($"IsNullable: {IsNullable}, ");
+		sb.Append ($"IsSmartEnum: {IsSmartEnum}, ");
 		sb.Append ($"DefaultValue: {DefaultValue}, ");
 		sb.Append ($"ReferenceKind: {ReferenceKind} }}");
 		return sb.ToString ();

src/rgen/Microsoft.Macios.Generator/DataModel/Property.cs

@@ -26,6 +26,11 @@ namespace Microsoft.Macios.Generator.DataModel;
 	/// </summary>
 	public string Type { get; } = string.Empty;
 
+	/// <summary>
+	/// Returns if the parameter type is a smart enum.
+	/// </summary>
+	public bool IsSmartEnum { get; }
+
 	/// <summary>
 	/// The platform availability of the property.
 	/// </summary>
@@ -67,12 +72,14 @@ namespace Microsoft.Macios.Generator.DataModel;
 	public ImmutableArray<Accessor> Accessors { get; } = [];
 
 	internal Property (string name, string type,
+		bool isSmartEnum,
 		SymbolAvailability symbolAvailability,
 		ImmutableArray<AttributeCodeChange> attributes,
 		ImmutableArray<SyntaxToken> modifiers, ImmutableArray<Accessor> accessors)
 	{
 		Name = name;
 		Type = type;
+		IsSmartEnum = isSmartEnum;
 		SymbolAvailability = symbolAvailability;
 		Attributes = attributes;
 		Modifiers = modifiers;
@@ -87,6 +94,8 @@ public bool Equals (Property other)
 			return false;
 		if (Type != other.Type)
 			return false;
+		if (IsSmartEnum != other.IsSmartEnum)
+			return false;
 		if (SymbolAvailability != other.SymbolAvailability)
 			return false;
 		if (ExportFieldData != other.ExportFieldData)
@@ -115,7 +124,7 @@ public override bool Equals (object? obj)
 	/// <inheritdoc />
 	public override int GetHashCode ()
 	{
-		return HashCode.Combine (Name, Type, Attributes, Modifiers, Accessors);
+		return HashCode.Combine (Name, Type, IsSmartEnum, Attributes, Modifiers, Accessors);
 	}
 
 	public static bool operator == (Property left, Property right)
@@ -169,6 +178,7 @@ public static bool TryCreate (PropertyDeclarationSyntax declaration, SemanticMod
 		change = new (
 			name: memberName,
 			type: type,
+			isSmartEnum: propertySymbol.Type.IsSmartEnum (),
 			symbolAvailability: propertySupportedPlatforms,
 			attributes: attributes,
 			modifiers: [.. declaration.Modifiers],
@@ -183,7 +193,7 @@ public static bool TryCreate (PropertyDeclarationSyntax declaration, SemanticMod
 	public override string ToString ()
 	{
 		var sb = new StringBuilder (
-			$"Name: '{Name}', Type: '{Type}', Supported Platforms: {SymbolAvailability}, ExportFieldData: '{ExportFieldData?.ToString () ?? "null"}', ExportPropertyData: '{ExportPropertyData?.ToString () ?? "null"}' Attributes: [");
+			$"Name: '{Name}', Type: '{Type}', IsSmartEnum: {IsSmartEnum}, Supported Platforms: {SymbolAvailability}, ExportFieldData: '{ExportFieldData?.ToString () ?? "null"}', ExportPropertyData: '{ExportPropertyData?.ToString () ?? "null"}' Attributes: [");
 		sb.AppendJoin (",", Attributes);
 		sb.Append ("], Modifiers: [");
 		sb.AppendJoin (",", Modifiers.Select (x => x.Text));

src/rgen/Microsoft.Macios.Generator/Extensions/TypeSymbolExtensions.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.Macios.Generator.Attributes;
 using Microsoft.Macios.Generator.Availability;
@@ -125,6 +126,29 @@ public static SymbolAvailability GetSupportedPlatforms (this ISymbol symbol)
 		return availability;
 	}
 
+	public static bool HasAttribute (this ISymbol symbol, string attribute)
+	{
+		var boundAttributes = symbol.GetAttributes ();
+		if (boundAttributes.Length == 0) {
+			return false;
+		}
+		foreach (var attributeData in boundAttributes) {
+			var attrName = attributeData.AttributeClass?.ToDisplayString ();
+			if (attrName == attribute) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	public static bool IsSmartEnum (this ITypeSymbol symbol)
+	{
+		// a type is a smart enum if its type is a enum one AND it was decorated with the
+		// binding type attribute
+		return symbol.TypeKind == TypeKind.Enum
+			   && symbol.HasAttribute (AttributesNames.BindingAttribute);
+	}
+
 	/// <summary>
 	/// Retrieve the data of an export attribute on a symbol.
 	/// </summary>

tests/rgen/Microsoft.Macios.Generator.Tests/DataModel/ClassCodeChangesTests.cs

@@ -263,6 +263,7 @@ public partial class MyClass {
 						new (
 							name: "Name",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name"])
@@ -276,7 +277,119 @@ public partial class MyClass {
 								new (AccessorKind.Setter, new (), [], []),
 							]
 						) {
+							ExportPropertyData = new ("name")
+						}
+					]
+				}
+			];
+
+			const string singlePropertySmartEnumClass = @"
+using ObjCBindings;
+
+namespace NS;
+
+[BindingType]
+public enum MyEnum {
+	None = 0,
+}
+
+[BindingType]
+public partial class MyClass {
+	[Export<Property> (""name"")]
+	public partial MyEnum Name { get; set; }
+}
+";
+
+			yield return [
+				singlePropertySmartEnumClass,
+				new CodeChanges (
+					bindingType: BindingType.Class,
+					name: "MyClass",
+					@namespace: ["NS"],
+					fullyQualifiedSymbol: "NS.MyClass",
+					symbolAvailability: new ()
+				) {
+					Attributes = [
+						new ("ObjCBindings.BindingTypeAttribute")
+					],
+					Modifiers = [
+						SyntaxFactory.Token (SyntaxKind.PublicKeyword),
+						SyntaxFactory.Token (SyntaxKind.PartialKeyword)
+					],
+					Properties = [
+						new (
+							name: "Name",
+							type: "NS.MyEnum",
+							isSmartEnum: true,
+							symbolAvailability: new (),
+							attributes: [
+								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name"])
+							],
+							modifiers: [
+								SyntaxFactory.Token (SyntaxKind.PublicKeyword),
+								SyntaxFactory.Token (SyntaxKind.PartialKeyword),
+							],
+							accessors: [
+								new (AccessorKind.Getter, new (), [], []),
+								new (AccessorKind.Setter, new (), [], []),
+							]
+						) {
+							ExportPropertyData = new ("name")
+						}
+					]
+				}
+			];
 
+			const string singlePropertyEnumClass = @"
+using ObjCBindings;
+
+namespace NS;
+
+public enum MyEnum {
+	None = 0,
+}
+
+[BindingType]
+public partial class MyClass {
+	[Export<Property> (""name"")]
+	public partial MyEnum Name { get; set; }
+}
+";
+
+			yield return [
+				singlePropertyEnumClass,
+				new CodeChanges (
+					bindingType: BindingType.Class,
+					name: "MyClass",
+					@namespace: ["NS"],
+					fullyQualifiedSymbol: "NS.MyClass",
+					symbolAvailability: new ()
+				) {
+					Attributes = [
+						new ("ObjCBindings.BindingTypeAttribute")
+					],
+					Modifiers = [
+						SyntaxFactory.Token (SyntaxKind.PublicKeyword),
+						SyntaxFactory.Token (SyntaxKind.PartialKeyword)
+					],
+					Properties = [
+						new (
+							name: "Name",
+							type: "NS.MyEnum",
+							isSmartEnum: false,
+							symbolAvailability: new (),
+							attributes: [
+								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name"])
+							],
+							modifiers: [
+								SyntaxFactory.Token (SyntaxKind.PublicKeyword),
+								SyntaxFactory.Token (SyntaxKind.PartialKeyword),
+							],
+							accessors: [
+								new (AccessorKind.Getter, new (), [], []),
+								new (AccessorKind.Setter, new (), [], []),
+							]
+						) {
 							ExportPropertyData = new ("name")
 						}
 					]
@@ -315,6 +428,7 @@ public partial class MyClass {
 						new (
 							name: "Name",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name", "ObjCBindings.Property.Notification"])
@@ -367,6 +481,7 @@ public partial class MyClass {
 						new (
 							name: "Name",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Field>", ["CONSTANT"])
@@ -422,6 +537,7 @@ public partial class MyClass {
 						new (
 							name: "Name",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name"])
@@ -476,6 +592,7 @@ public partial class MyClass {
 						new (
 							name: "Name",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["name"])
@@ -494,6 +611,7 @@ public partial class MyClass {
 						new (
 							name: "Surname",
 							type: "string",
+							isSmartEnum: false,
 							symbolAvailability: new (),
 							attributes: [
 								new ("ObjCBindings.ExportAttribute<ObjCBindings.Property>", ["surname"])