Add diagnostic and test for pointer types

Author: Sergio0694

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/AnalyzerReleases.Shipped.md

@@ -18,3 +18,4 @@ WCTDP0008 | CommunityToolkit.GeneratedDependencyPropertyDependencyPropertyGenera
 WCTDP0009 | CommunityToolkit.GeneratedDependencyPropertyDependencyPropertyGenerator | Warning |
 WCTDP0010 | CommunityToolkit.GeneratedDependencyPropertyDependencyPropertyGenerator | Warning |
 WCTDP0011 | CommunityToolkit.GeneratedDependencyPropertyDependencyPropertyGenerator | Warning |
+WCTDP0012 | CommunityToolkit.GeneratedDependencyPropertyDependencyPropertyGenerator | Error |

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/DependencyPropertyGenerator.Execute.cs

@@ -115,8 +115,15 @@ public static bool IsCandidateSymbolValid(IPropertySymbol propertySymbol, bool u
                 return false;
             }
 
-            // Also ignore all properties that have an invalid declaration
-            if (propertySymbol.IsStatic || propertySymbol.ReturnsByRef || propertySymbol.ReturnsByRefReadonly || propertySymbol.Type.IsRefLikeType)
+            // Also ignore all properties returning a byref-like value. We don't need to also
+            // check for ref values here, as that's already validated by the syntax filter.
+            if (propertySymbol.Type.IsRefLikeType)
+            {
+                return false;
+            }
+
+            // Pointer types are never allowed
+            if (propertySymbol.Type.TypeKind is TypeKind.Pointer or TypeKind.FunctionPointer)
             {
                 return false;
             }

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/Diagnostics/Analyzers/InvalidPropertySymbolDeclarationAnalyzer.cs

@@ -22,7 +22,8 @@ public sealed class InvalidPropertySymbolDeclarationAnalyzer : DiagnosticAnalyze
     [
         InvalidPropertyDeclarationIsNotIncompletePartialDefinition,
         InvalidPropertyDeclarationReturnsByRef,
-        InvalidPropertyDeclarationReturnsRefLikeType
+        InvalidPropertyDeclarationReturnsRefLikeType,
+        InvalidPropertyDeclarationReturnsPointerType
     ];
 
     /// <inheritdoc/>
@@ -86,15 +87,22 @@ public override void Initialize(AnalysisContext context)
                         attributeData.GetLocation(),
                         propertySymbol));
                 }
-
-                // Emit an error if the property type is a ref struct
-                if (propertySymbol.Type.IsRefLikeType)
+                else if (propertySymbol.Type.IsRefLikeType)
                 {
+                    // Emit an error if the property type is a ref struct
                     context.ReportDiagnostic(Diagnostic.Create(
                         InvalidPropertyDeclarationReturnsRefLikeType,
                         attributeData.GetLocation(),
                         propertySymbol));
                 }
+                else if (propertySymbol.Type.TypeKind is TypeKind.Pointer or TypeKind.FunctionPointer)
+                {
+                    // Emit a diagnostic if the type is a pointer type
+                    context.ReportDiagnostic(Diagnostic.Create(
+                        InvalidPropertyDeclarationReturnsPointerType,
+                        attributeData.GetLocation(),
+                        propertySymbol));
+                }
             }, SymbolKind.Property);
         });
     }

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.SourceGenerators/Diagnostics/DiagnosticDescriptors.cs

@@ -153,4 +153,20 @@ internal static class DiagnosticDescriptors
         isEnabledByDefault: true,
         description: "Properties annotated with [GeneratedDependencyProperty] and setting 'DefaultValue' should do so with an expression of a type comparible with the property type. Alternatively, the 'Get(ref object)' method should be implemented to handle the type mismatch.",
         helpLinkUri: "https://aka.ms/toolkit/labs/windows");
+
+    /// <summary>
+    /// Gets a <see cref="DiagnosticDescriptor"/> for when <c>[ObservableProperty]</c> is used on a property that returns a pointer type.
+    /// <para>
+    /// Format: <c>"The property {0}.{1} returns a pointer or function pointer value ([ObservableProperty] must be used on properties of a non pointer-like type)"</c>.
+    /// </para>
+    /// </summary>
+    public static readonly DiagnosticDescriptor InvalidPropertyDeclarationReturnsPointerType = new(
+        id: "WCTDP0012",
+        title: "Using [GeneratedDependencyProperty] on a property that returns pointer type",
+        messageFormat: """The property '{0}' cannot be used to generate a dependency property, as it returns a pointer value ([GeneratedDependencyProperty] must be used on properties returning a non pointer value)""",
+        category: typeof(DependencyPropertyGenerator).FullName,
+        defaultSeverity: DiagnosticSeverity.Error,
+        isEnabledByDefault: true,
+        description: "Properties annotated with [GeneratedDependencyProperty] must not return a pointer value (only reference types and non byref-like types are supported).",
+        helpLinkUri: "https://aka.ms/toolkit/labs/windows");
 }

components/DependencyPropertyGenerator/CommunityToolkit.DependencyPropertyGenerator.Tests/Test_Analyzers.cs

@@ -339,6 +339,44 @@ public partial class MyControl : Control
         await CSharpAnalyzerTest<InvalidPropertySymbolDeclarationAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
     }
 
+    [TestMethod]
+    public async Task InvalidPropertySymbolDeclarationAnalyzer_ReturnsPointerType_Warns()
+    {
+        const string source = """
+            using CommunityToolkit.WinUI;
+            using Windows.UI.Xaml.Controls;
+            
+            namespace MyApp;
+
+            public unsafe partial class MyControl : Control
+            {
+                [{|WCTDP0012:GeneratedDependencyProperty|}]
+                public partial int* {|CS9248:Name|} { get; set; }
+            }
+            """;
+
+        await CSharpAnalyzerTest<InvalidPropertySymbolDeclarationAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
+    }
+
+    [TestMethod]
+    public async Task InvalidPropertySymbolDeclarationAnalyzer_ReturnsFunctionPointerType_Warns()
+    {
+        const string source = """
+            using CommunityToolkit.WinUI;
+            using Windows.UI.Xaml.Controls;
+            
+            namespace MyApp;
+
+            public unsafe partial class MyControl : Control
+            {
+                [{|WCTDP0012:GeneratedDependencyProperty|}]
+                public partial delegate* unmanaged[Stdcall]<int, void> {|CS9248:Name|} { get; set; }
+            }
+            """;
+
+        await CSharpAnalyzerTest<InvalidPropertySymbolDeclarationAnalyzer>.VerifyAnalyzerAsync(source, LanguageVersion.CSharp13);
+    }
+
     [TestMethod]
     public async Task InvalidPropertyContainingTypeDeclarationAnalyzer_NoAttribute_DoesNotWarn()
     {