Add more analyzers, enable unit tests for partial properties

dotnet Community Toolkit.sln

@@ -91,6 +91,8 @@ Project("{D954291E-2A0B-460D-934E-DC6B0785DB48}") = "CommunityToolkit.Mvvm.CodeF
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.CodeFixers.Roslyn4120", "src\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120\CommunityToolkit.Mvvm.CodeFixers.Roslyn4120.csproj", "{98572004-D29A-486E-8053-6D409557CE44}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommunityToolkit.Mvvm.Roslyn4120.UnitTests", "tests\CommunityToolkit.Mvvm.Roslyn4120.UnitTests\CommunityToolkit.Mvvm.Roslyn4120.UnitTests.csproj", "{87BF1537-935A-414D-8318-458F61A6E562}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -525,6 +527,26 @@ Global
 		{98572004-D29A-486E-8053-6D409557CE44}.Release|x64.Build.0 = Release|Any CPU
 		{98572004-D29A-486E-8053-6D409557CE44}.Release|x86.ActiveCfg = Release|Any CPU
 		{98572004-D29A-486E-8053-6D409557CE44}.Release|x86.Build.0 = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|ARM.ActiveCfg = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|ARM.Build.0 = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|ARM64.ActiveCfg = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|ARM64.Build.0 = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|x64.Build.0 = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Debug|x86.Build.0 = Debug|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|Any CPU.Build.0 = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|ARM.ActiveCfg = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|ARM.Build.0 = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|ARM64.ActiveCfg = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|ARM64.Build.0 = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|x64.ActiveCfg = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|x64.Build.0 = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|x86.ActiveCfg = Release|Any CPU
+		{87BF1537-935A-414D-8318-458F61A6E562}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -548,6 +570,7 @@ Global
 		{ECFE93AA-4B98-4292-B3FA-9430D513B4F9} = {B30036C4-D514-4E5B-A323-587A061772CE}
 		{4FCD501C-1BB5-465C-AD19-356DAB6600C6} = {B30036C4-D514-4E5B-A323-587A061772CE}
 		{C342302D-A263-42D6-B8EE-01DEF8192690} = {B30036C4-D514-4E5B-A323-587A061772CE}
+		{87BF1537-935A-414D-8318-458F61A6E562} = {B30036C4-D514-4E5B-A323-587A061772CE}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {5403B0C4-F244-4F73-A35C-FE664D0F4345}
@@ -556,6 +579,7 @@ Global
 		tests\CommunityToolkit.Mvvm.ExternalAssembly\CommunityToolkit.Mvvm.ExternalAssembly.projitems*{4fcd501c-1bb5-465c-ad19-356dab6600c6}*SharedItemsImports = 5
 		tests\CommunityToolkit.Mvvm.UnitTests\CommunityToolkit.Mvvm.UnitTests.projitems*{5b44f7f1-dca2-4776-924e-a266f7bbf753}*SharedItemsImports = 5
 		src\CommunityToolkit.Mvvm.SourceGenerators\CommunityToolkit.Mvvm.SourceGenerators.projitems*{5e7f1212-a54b-40ca-98c5-1ff5cd1a1638}*SharedItemsImports = 13
+		tests\CommunityToolkit.Mvvm.UnitTests\CommunityToolkit.Mvvm.UnitTests.projitems*{87bf1537-935a-414d-8318-458f61a6e562}*SharedItemsImports = 5
 		src\CommunityToolkit.Mvvm.CodeFixers\CommunityToolkit.Mvvm.CodeFixers.projitems*{98572004-d29a-486e-8053-6d409557ce44}*SharedItemsImports = 5
 		src\CommunityToolkit.Mvvm.CodeFixers\CommunityToolkit.Mvvm.CodeFixers.projitems*{a2ebda90-b720-430d-83f5-c6bcc355232c}*SharedItemsImports = 13
 		tests\CommunityToolkit.Mvvm.UnitTests\CommunityToolkit.Mvvm.UnitTests.projitems*{ad9c3223-8e37-4fd4-a0d4-a45119551d3a}*SharedItemsImports = 5

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "8.0.403",
+    "version": "9.0.100",
     "rollForward": "latestFeature",
     "allowPrerelease": false
   }

src/CommunityToolkit.Mvvm.SourceGenerators/AnalyzerReleases.Shipped.md

@@ -92,4 +92,7 @@ MVVMTK0047 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator
 MVVMTK0048 | CommunityToolkit.Mvvm.SourceGenerators.RelayCommandGenerator | Warning | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0048
 MVVMTK0049 | CommunityToolkit.Mvvm.SourceGenerators.INotifyPropertyChangedGenerator | Warning | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0049
 MVVMTK0050 | CommunityToolkit.Mvvm.SourceGenerators.ObservableObjectGenerator | Warning | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0050
-MVVMTK0051 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Info | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0050
+MVVMTK0051 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Info | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0051
+MVVMTK0052 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0052
+MVVMTK0053 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0053
+MVVMTK0054 | CommunityToolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/errors/mvvmtk0054

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

@@ -41,6 +41,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ComponentModel\TransitiveMembersGenerator.Execute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\AsyncVoidReturningRelayCommandMethodAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\InvalidGeneratedPropertyObservablePropertyAttributeAnalyzer.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\InvalidPartialPropertyLevelObservablePropertyAttributeAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\WinRTClassUsingNotifyPropertyChangedAttributesAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\WinRTGeneratedBindableCustomPropertyWithBasesMemberAnalyzer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Diagnostics\Analyzers\WinRTRelayCommandIsNotGeneratedBindableCustomPropertyCompatibleAnalyzer.cs" />

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

@@ -71,7 +71,7 @@ static bool IsCandidateField(SyntaxNode node, out TypeDeclarationSyntax? contain
         /// <param name="node">The <see cref="MemberDeclarationSyntax"/> instance to process.</param>
         /// <param name="semanticModel">The <see cref="SemanticModel"/> instance for the current run.</param>
         /// <returns>Whether <paramref name="node"/> is valid.</returns>
-        public static bool IsCandidateValidForCompilation(SyntaxNode node, SemanticModel semanticModel)
+        public static bool IsCandidateValidForCompilation(MemberDeclarationSyntax node, SemanticModel semanticModel)
         {
             // At least C# 8 is always required
             if (!semanticModel.Compilation.HasLanguageVersionAtLeastEqualTo(LanguageVersion.CSharp8))
@@ -90,6 +90,35 @@ public static bool IsCandidateValidForCompilation(SyntaxNode node, SemanticModel
             return true;
         }
 
+        /// <summary>
+        /// Performs additional checks before running the core generation logic.
+        /// </summary>
+        /// <param name="memberSymbol">The input <see cref="ISymbol"/> instance to process.</param>
+        /// <returns>Whether <paramref name="memberSymbol"/> is valid.</returns>
+        public static bool IsCandidateSymbolValid(ISymbol memberSymbol)
+        {
+#if ROSLYN_4_12_0_OR_GREATER
+            // We only need additional checks for properties (Roslyn already validates things for fields in our scenarios)
+            if (memberSymbol is IPropertySymbol propertySymbol)
+            {
+                // Ensure that the property declaration is a partial definition with no implementation
+                if (propertySymbol is not { IsPartialDefinition: true, PartialImplementationPart: null })
+                {
+                    return false;
+                }
+
+                // Also ignore all properties that have an invalid declaration
+                if (propertySymbol.ReturnsByRef || propertySymbol.ReturnsByRefReadonly || propertySymbol.Type.IsRefLikeType)
+                {
+                    return false;
+                }
+            }
+#endif
+
+            // We assume all other cases are supported (other failure cases will be detected later)
+            return true;
+        }
+
         /// <summary>
         /// Gets the candidate <see cref="MemberDeclarationSyntax"/> after the initial filtering.
         /// </summary>
@@ -140,13 +169,11 @@ public static bool TryGetInfo(
                 return false;
             }
 
-            using ImmutableArrayBuilder<DiagnosticInfo> builder = ImmutableArrayBuilder<DiagnosticInfo>.Rent();
-
             // Validate the target type
             if (!IsTargetTypeValid(memberSymbol, out bool shouldInvokeOnPropertyChanging))
             {
                 propertyInfo = null;
-                diagnostics = builder.ToImmutable();
+                diagnostics = ImmutableArray<DiagnosticInfo>.Empty;
 
                 return false;
             }
@@ -168,7 +195,7 @@ public static bool TryGetInfo(
             if (fieldName == propertyName && memberSyntax.IsKind(SyntaxKind.FieldDeclaration))
             {
                 propertyInfo = null;
-                diagnostics = builder.ToImmutable();
+                diagnostics = ImmutableArray<DiagnosticInfo>.Empty;
 
                 // If the generated property would collide, skip generating it entirely. This makes sure that
                 // users only get the helpful diagnostic about the collision, and not the normal compiler error
@@ -182,7 +209,7 @@ public static bool TryGetInfo(
             if (IsGeneratedPropertyInvalid(propertyName, GetPropertyType(memberSymbol)))
             {
                 propertyInfo = null;
-                diagnostics = builder.ToImmutable();
+                diagnostics = ImmutableArray<DiagnosticInfo>.Empty;
 
                 return false;
             }
@@ -232,6 +259,8 @@ public static bool TryGetInfo(
 
             token.ThrowIfCancellationRequested();
 
+            using ImmutableArrayBuilder<DiagnosticInfo> builder = ImmutableArrayBuilder<DiagnosticInfo>.Rent();
+
             // Gather attributes info
             foreach (AttributeData attributeData in memberSymbol.GetAttributes())
             {

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

@@ -9,7 +9,6 @@
 using CommunityToolkit.Mvvm.SourceGenerators.Helpers;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;
@@ -38,6 +37,14 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                         return default;
                     }
 
+                    // Validate the symbol as well before doing any work
+                    if (!Execute.IsCandidateSymbolValid(context.TargetSymbol))
+                    {
+                        return default;
+                    }
+
+                    token.ThrowIfCancellationRequested();
+
                     // Get the hierarchy info for the target symbol, and try to gather the property info
                     HierarchyInfo hierarchy = HierarchyInfo.From(context.TargetSymbol.ContainingType);
 

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

@@ -0,0 +1,103 @@
+// 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.
+
+#if ROSLYN_4_12_0_OR_GREATER
+
+using System.Collections.Immutable;
+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 whenever <c>[ObservableProperty]</c> is used on an invalid partial property declaration.
+/// </summary>
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public sealed class InvalidPartialPropertyLevelObservablePropertyAttributeAnalyzer : DiagnosticAnalyzer
+{
+    /// <inheritdoc/>
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(
+        InvalidObservablePropertyDeclarationIsNotIncompletePartialDefinition,
+        InvalidObservablePropertyDeclarationReturnsByRef,
+        InvalidObservablePropertyDeclarationReturnsRefLikeType);
+
+    /// <inheritdoc/>
+    public override void Initialize(AnalysisContext context)
+    {
+        // This generator is intentionally also analyzing generated code, because Roslyn will interpret properties
+        // that have '[GeneratedCode]' on them as being generated (and the same will apply to all partial parts).
+        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.Analyze | GeneratedCodeAnalysisFlags.ReportDiagnostics);
+        context.EnableConcurrentExecution();
+
+        context.RegisterCompilationStartAction(static context =>
+        {
+            // Get the [ObservableProperty] and [GeneratedCode] symbols
+            if (context.Compilation.GetTypeByMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservablePropertyAttribute") is not INamedTypeSymbol observablePropertySymbol ||
+                context.Compilation.GetTypeByMetadataName("System.CodeDom.Compiler.GeneratedCodeAttribute") is not { } generatedCodeAttributeSymbol)
+            {
+                return;
+            }
+
+            context.RegisterSymbolAction(context =>
+            {
+                // Ensure that we have some target property to analyze (also skip implementation parts)
+                if (context.Symbol is not IPropertySymbol { PartialDefinitionPart: null } propertySymbol)
+                {
+                    return;
+                }
+
+                // If the property is not using [ObservableProperty], there's nothing to do
+                if (!context.Symbol.TryGetAttributeWithType(observablePropertySymbol, out AttributeData? observablePropertyAttribute))
+                {
+                    return;
+                }
+
+                // Emit an error if the property is not a partial definition with no implementation...
+                if (propertySymbol is not { IsPartialDefinition: true, PartialImplementationPart: null })
+                {
+                    // ...But only if it wasn't actually generated by the [ObservableProperty] generator.
+                    bool isImplementationAllowed =
+                        propertySymbol is { IsPartialDefinition: true, PartialImplementationPart: IPropertySymbol implementationPartSymbol } &&
+                        implementationPartSymbol.TryGetAttributeWithType(generatedCodeAttributeSymbol, out AttributeData? generatedCodeAttributeData) &&
+                        generatedCodeAttributeData.TryGetConstructorArgument(0, out string? toolName) &&
+                        toolName == typeof(ObservablePropertyGenerator).FullName;
+
+                    // Emit the diagnostic only for cases that were not valid generator outputs
+                    if (!isImplementationAllowed)
+                    {
+                        context.ReportDiagnostic(Diagnostic.Create(
+                            InvalidObservablePropertyDeclarationIsNotIncompletePartialDefinition,
+                            observablePropertyAttribute.GetLocation(),
+                            propertySymbol.ContainingType,
+                            propertySymbol.Name));
+                    }
+                }
+
+                // Emit an error if the property returns a value by ref
+                if (propertySymbol.ReturnsByRef || propertySymbol.ReturnsByRefReadonly)
+                {
+                    context.ReportDiagnostic(Diagnostic.Create(
+                        InvalidObservablePropertyDeclarationReturnsByRef,
+                        observablePropertyAttribute.GetLocation(),
+                        propertySymbol.ContainingType,
+                        propertySymbol.Name));
+                }
+
+                // Emit an error if the property type is a ref struct
+                if (propertySymbol.Type.IsRefLikeType)
+                {
+                    context.ReportDiagnostic(Diagnostic.Create(
+                        InvalidObservablePropertyDeclarationReturnsRefLikeType,
+                        observablePropertyAttribute.GetLocation(),
+                        propertySymbol.ContainingType,
+                        propertySymbol.Name));
+                }
+            }, SymbolKind.Property);
+        });
+    }
+}
+
+#endif

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

@@ -60,7 +60,9 @@ public override void Initialize(AnalysisContext context)
                             InvalidPropertyDeclarationForObservableProperty,
                             observablePropertyAttribute.GetLocation(),
                             propertySymbol.ContainingType,
-                            propertySymbol));
+                            propertySymbol.Name));
+
+                        return;
                     }
                 }
             }, SymbolKind.Property);
@@ -91,6 +93,14 @@ internal static bool IsValidCandidateProperty(SyntaxNode node, out TypeDeclarati
             return false;
         }
 
+        // Static properties are not supported
+        if (property.Modifiers.Any(SyntaxKind.StaticKeyword))
+        {
+            containingTypeNode = null;
+
+            return false;
+        }
+
         // The accessors must be a get and a set (with any accessibility)
         if (accessors[0].Kind() is not (SyntaxKind.GetAccessorDeclaration or SyntaxKind.SetAccessorDeclaration) ||
             accessors[1].Kind() is not (SyntaxKind.GetAccessorDeclaration or SyntaxKind.SetAccessorDeclaration))

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

@@ -51,7 +51,7 @@ public override void Initialize(AnalysisContext context)
                         UnsupportedRoslynVersionForObservablePartialPropertySupport,
                         propertySymbol.Locations.FirstOrDefault(),
                         propertySymbol.ContainingType,
-                        propertySymbol));
+                        propertySymbol.Name));
                 }
             }, SymbolKind.Property);
         });