Add InvalidTypeForNotifyPropertyChangedRecipientsError

Author: Sergio0694

src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.projitems

@@ -39,6 +39,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ComponentModel\ObservableValidatorValidateAllPropertiesGenerator.Execute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ComponentModel\TransitiveMembersGenerator.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ComponentModel\TransitiveMembersGenerator.Execute.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\InvalidClassLevelNotifyPropertyChangedRecipientsAttributeAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\ClassUsingAttributeInsteadOfInheritanceAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\FieldWithOrphanedDependentObservablePropertyAttributesAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\FieldReferenceForObservablePropertyFieldAnalyzer.cs" />

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

@@ -555,26 +555,6 @@ private static bool TryGetIsNotifyingRecipients(
             return false;
         }
 
-        /// <summary>
-        /// Checks whether a given type using <c>[NotifyPropertyChangedRecipients]</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.InheritsFromFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservableRecipient") &&
-                !typeSymbol.HasOrInheritsAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservableRecipientAttribute"))
-            {
-                return Diagnostic.Create(
-                    InvalidTypeForNotifyPropertyChangedRecipientsError,
-                    typeSymbol.Locations.FirstOrDefault(),
-                    typeSymbol);
-            }
-
-            return null;
-        }
-
         /// <summary>
         /// Checks whether a given generated property should also validate its value.
         /// </summary>

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

@@ -121,16 +121,6 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                 static (node, _) => node is ClassDeclarationSyntax { AttributeLists.Count: > 0 },
                 static (context, _) => (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!);
 
-        // Filter only the type symbols with [NotifyPropertyChangedRecipients] and create diagnostics for them
-        IncrementalValuesProvider<Diagnostic> notifyRecipientsErrors =
-            classSymbols
-            .Where(static item => item.HasAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.NotifyPropertyChangedRecipientsAttribute"))
-            .Select(static (item, _) => Execute.GetIsNotifyingRecipientsDiagnosticForType(item))
-            .Where(static item => item is not null)!;
-
-        // Output the diagnostics for [NotifyPropertyChangedRecipients]
-        context.ReportDiagnostics(notifyRecipientsErrors);
-
         // Filter only the type symbols with [NotifyDataErrorInfo] and create diagnostics for them
         IncrementalValuesProvider<Diagnostic> notifyDataErrorInfoErrors =
             classSymbols

src/CommunityToolkit.Mvvm.SourceGenerators/Diagnostics/Analyzers/InvalidClassLevelNotifyPropertyChangedRecipientsAttributeAnalyzer.cs

@@ -0,0 +1,54 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.Immutable;
+using System.Linq;
+using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
+
+namespace CommunityToolkit.Mvvm.SourceGenerators;
+
+/// <summary>
+/// A diagnostic analyzer that generates an error when a class level <c>[NotifyPropertyChangedRecipients]</c> use is detected.
+/// </summary>
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public sealed class InvalidClassLevelNotifyPropertyChangedRecipientsAttributeAnalyzer : DiagnosticAnalyzer
+{
+    /// <inheritdoc/>
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(InvalidTypeForNotifyPropertyChangedRecipientsError);
+
+    /// <inheritdoc/>
+    public override void Initialize(AnalysisContext context)
+    {
+        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
+        context.EnableConcurrentExecution();
+
+        context.RegisterSymbolAction(static context =>
+        {
+            // We're looking for all class declarations
+            if (context.Symbol is not INamedTypeSymbol { TypeKind: TypeKind.Class, IsImplicitlyDeclared: false } classSymbol)
+            {
+                return;
+            }
+
+            // Only inspect class that are using [NotifyPropertyChangedRecipients]
+            if (!classSymbol.HasAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.NotifyPropertyChangedRecipientsAttribute"))
+            {
+                return;
+            }
+
+            // If the containing type is not valid, emit a diagnostic
+            if (!classSymbol.InheritsFromFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservableRecipient") &&
+                !classSymbol.HasOrInheritsAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservableRecipientAttribute"))
+            {
+                context.ReportDiagnostic(Diagnostic.Create(
+                    InvalidTypeForNotifyPropertyChangedRecipientsError,
+                    classSymbol.Locations.FirstOrDefault(),
+                    classSymbol));
+            }
+        }, SymbolKind.NamedType);
+    }
+}