Enable diagnostics for class-level recipient/validation attributes

Author: Sergio0694

CommunityToolkit.Mvvm.SourceGenerators/AnalyzerReleases.Shipped.md

@@ -33,3 +33,5 @@ MVVMTK0023 | CommunityToolkit.Mvvm.SourceGenerators.ICommandGenerator | Error |
 MVVMTK0024 | CommunityToolkit.Mvvm.SourceGenerators.ICommandGenerator | Error | See https://aka.ms/mvvmtoolkit/error
 MVVMTK0025 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
 MVVMTK0026 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0027 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0028 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.Execute.cs

@@ -488,6 +488,26 @@ private static bool TryGetIsNotifyingRecipients(
             return false;
         }
 
+        /// <summary>
+        /// Checks whether a given type using <c>[NotifyRecipients]</c> is valid and creates a <see cref="Diagnostic"/> if not.
+        /// </summary>
+        /// <param name="typeSymbol">The input <see cref="INamedTypeSymbol"/> instance to process.</param>
+        /// <returns>The <see cref="Diagnostic"/> for <paramref name="typeSymbol"/>, if not a valid type.</returns>
+        public static Diagnostic? GetIsNotifyingRecipientsDiagnosticForType(INamedTypeSymbol typeSymbol)
+        {
+            // If the containing type is valid, track it
+            if (!typeSymbol.InheritsFromFullyQualifiedName("global::CommunityToolkit.Mvvm.ComponentModel.ObservableRecipient") &&
+                !typeSymbol.HasOrInheritsAttributeWithFullyQualifiedName("global::CommunityToolkit.Mvvm.ComponentModel.ObservableRecipientAttribute"))
+            {
+                return Diagnostic.Create(
+                    InvalidTypeForNotifyRecipientsError,
+                    typeSymbol.Locations.FirstOrDefault(),
+                    typeSymbol);
+            }
+
+            return null;
+        }
+
         /// <summary>
         /// Checks whether a given generated property should also validate its value.
         /// </summary>
@@ -558,6 +578,25 @@ private static bool TryGetNotifyDataErrorInfo(
             return false;
         }
 
+        /// <summary>
+        /// Checks whether a given type using <c>[NotifyDataErrorInfo]</c> is valid and creates a <see cref="Diagnostic"/> if not.
+        /// </summary>
+        /// <param name="typeSymbol">The input <see cref="INamedTypeSymbol"/> instance to process.</param>
+        /// <returns>The <see cref="Diagnostic"/> for <paramref name="typeSymbol"/>, if not a valid type.</returns>
+        public static Diagnostic? GetIsNotifyDataErrorInfoDiagnosticForType(INamedTypeSymbol typeSymbol)
+        {
+            // If the containing type is valid, track it
+            if (!typeSymbol.InheritsFromFullyQualifiedName("global::CommunityToolkit.Mvvm.ComponentModel.ObservableValidator"))
+            {
+                return Diagnostic.Create(
+                    InvalidTypeForNotifyDataErrorInfoError,
+                    typeSymbol.Locations.FirstOrDefault(),
+                    typeSymbol);
+            }
+
+            return null;
+        }
+
         /// <summary>
         /// Gets a <see cref="CompilationUnitSyntax"/> instance with the cached args for property changing notifications.
         /// </summary>

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.cs

@@ -135,5 +135,32 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                 context.AddSource("__KnownINotifyPropertyChangedArgs.g.cs", compilationUnit.GetText(Encoding.UTF8));
             }
         });
+
+        // Get all class declarations with at least one attribute
+        IncrementalValuesProvider<INamedTypeSymbol> classSymbols =
+            context.SyntaxProvider
+            .CreateSyntaxProvider(
+                static (node, _) => node is ClassDeclarationSyntax { AttributeLists.Count: > 0 },
+                static (context, _) => (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!);
+
+        // Filter only the type symbols with [NotifyRecipients] and create diagnostics for them
+        IncrementalValuesProvider<Diagnostic> notifyRecipientsErrors =
+            classSymbols
+            .Where(static item => item.HasAttributeWithFullyQualifiedName("global::CommunityToolkit.Mvvm.ComponentModel.NotifyRecipientsAttribute"))
+            .Select(static (item, _) => Execute.GetIsNotifyingRecipientsDiagnosticForType(item))
+            .Where(static item => item is not null)!;
+
+        // Output the diagnostics for [NotifyRecipients]
+        context.ReportDiagnostics(notifyRecipientsErrors);
+
+        // Filter only the type symbols with [NotifyDataErrorInfo] and create diagnostics for them
+        IncrementalValuesProvider<Diagnostic> notifyDataErrorInfoErrors =
+            classSymbols
+            .Where(static item => item.HasAttributeWithFullyQualifiedName("global::CommunityToolkit.Mvvm.ComponentModel.NotifyDataErrorInfoAttribute"))
+            .Select(static (item, _) => Execute.GetIsNotifyDataErrorInfoDiagnosticForType(item))
+            .Where(static item => item is not null)!;
+
+        // Output the diagnostics for [NotifyDataErrorInfo]
+        context.ReportDiagnostics(notifyDataErrorInfoErrors);
     }
 }

CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/DiagnosticDescriptors.cs

@@ -427,4 +427,36 @@ internal static class DiagnosticDescriptors
         isEnabledByDefault: true,
         description: "Cannot apply [NotifyDataErrorInfo] to fields that don't have any validation attributes to use during validation.",
         helpLinkUri: "https://aka.ms/mvvmtoolkit");
+
+    /// <summary>
+    /// Gets a <see cref="DiagnosticDescriptor"/> indicating when <c>[NotifyRecipients]</c> is applied to an invalid type.
+    /// <para>
+    /// Format: <c>"The type {0} cannot be annotated with [NotifyRecipients], as it doesn't inherit from ObservableRecipient, nor does it use [ObservableRecipient]"</c>.
+    /// </para>
+    /// </summary>
+    public static readonly DiagnosticDescriptor InvalidTypeForNotifyRecipientsError = new DiagnosticDescriptor(
+        id: "MVVMTK0027",
+        title: "Invalid type for [NotifyRecipients] attribute",
+        messageFormat: "The type {0} cannot be annotated with [NotifyRecipients], as it doesn't inherit from ObservableRecipient, nor does it use [ObservableRecipient]",
+        category: typeof(ObservablePropertyGenerator).FullName,
+        defaultSeverity: DiagnosticSeverity.Error,
+        isEnabledByDefault: true,
+        description: "Types annotated with [NotifyRecipients] must inherit from ObservableRecipient or be annotated with [ObservableRecipient] (including base types).",
+        helpLinkUri: "https://aka.ms/mvvmtoolkit");
+
+    /// <summary>
+    /// Gets a <see cref="DiagnosticDescriptor"/> indicating when <c>[NotifyDataErrorInfo]</c> is applied to an invalid type.
+    /// <para>
+    /// Format: <c>"The type {0} cannot be annotated with [NotifyDataErrorInfo], as it doesn't inherit from ObservableValidator"</c>.
+    /// </para>
+    /// </summary>
+    public static readonly DiagnosticDescriptor InvalidTypeForNotifyDataErrorInfoError = new DiagnosticDescriptor(
+        id: "MVVMTK0028",
+        title: "Invalid type for [NotifyDataErrorInfo] attribute",
+        messageFormat: "The type {0} cannot be annotated with [NotifyDataErrorInfo], as it doesn't inherit from ObservableValidator",
+        category: typeof(ObservablePropertyGenerator).FullName,
+        defaultSeverity: DiagnosticSeverity.Error,
+        isEnabledByDefault: true,
+        description: "Types annotated with [NotifyDataErrorInfo] must inherit from ObservableRecipient.",
+        helpLinkUri: "https://aka.ms/mvvmtoolkit");
 }