MVVM Toolkit vNext: source generators

Microsoft.Toolkit.Mvvm.SourceGenerators/AnalyzerReleases.Shipped.md

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+; Shipped analyzer releases
+; https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md

Microsoft.Toolkit.Mvvm.SourceGenerators/AnalyzerReleases.Unshipped.md

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+; Unshipped analyzer release
+; https://github.com/dotnet/roslyn-analyzers/blob/main/src/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
+
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+MVVMTK0001 | Microsoft.Toolkit.Mvvm.SourceGenerators.INotifyPropertyChangedGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0002 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableObjectGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0003 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableRecipientGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0004 | Microsoft.Toolkit.Mvvm.SourceGenerators.INotifyPropertyChangedGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0005 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableObjectGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0006 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableObjectGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0007 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableRecipientGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0008 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservableRecipientGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0009 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0010 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0011 | Microsoft.Toolkit.Mvvm.SourceGenerators.ObservablePropertyGenerator | Error | See https://aka.ms/mvvmtoolkit/error
+MVVMTK0012 | Microsoft.Toolkit.Mvvm.SourceGenerators.ICommandGenerator | Error | See https://aka.ms/mvvmtoolkit/error

Microsoft.Toolkit.Mvvm.SourceGenerators/Attributes/NotNullWhenAttribute.cs

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+// 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.
+
+namespace System.Diagnostics.CodeAnalysis
+{
+    /// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter will not be null even if the corresponding type allows it.</summary>
+    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
+    internal sealed class NotNullWhenAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NotNullWhenAttribute"/> class.
+        /// </summary>
+        /// <param name="returnValue">The return value condition. If the method returns this value, the associated parameter will not be null.</param>
+        public NotNullWhenAttribute(bool returnValue)
+        {
+            ReturnValue = returnValue;
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether the annotated parameter will be null depending on the return value.
+        /// </summary>
+        public bool ReturnValue { get; }
+    }
+}

Microsoft.Toolkit.Mvvm.SourceGenerators/ComponentModel/INotifyPropertyChangedGenerator.cs

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+// 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.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.Toolkit.Mvvm.SourceGenerators.Extensions;
+using static Microsoft.Toolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
+
+namespace Microsoft.Toolkit.Mvvm.SourceGenerators
+{
+    /// <summary>
+    /// A source generator for the <c>INotifyPropertyChangedAttribute</c> type.
+    /// </summary>
+    [Generator]
+    public sealed class INotifyPropertyChangedGenerator : TransitiveMembersGenerator
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="INotifyPropertyChangedGenerator"/> class.
+        /// </summary>
+        public INotifyPropertyChangedGenerator()
+            : base("Microsoft.Toolkit.Mvvm.ComponentModel.INotifyPropertyChangedAttribute")
+        {
+        }
+
+        /// <inheritdoc/>
+        protected override DiagnosticDescriptor TargetTypeErrorDescriptor => INotifyPropertyChangedGeneratorError;
+
+        /// <inheritdoc/>
+        protected override bool ValidateTargetType(
+            GeneratorExecutionContext context,
+            AttributeData attributeData,
+            ClassDeclarationSyntax classDeclaration,
+            INamedTypeSymbol classDeclarationSymbol,
+            [NotNullWhen(false)] out DiagnosticDescriptor? descriptor)
+        {
+            INamedTypeSymbol iNotifyPropertyChangedSymbol = context.Compilation.GetTypeByMetadataName("System.ComponentModel.INotifyPropertyChanged")!;
+
+            // Check if the type already implements INotifyPropertyChanged
+            if (classDeclarationSymbol.AllInterfaces.Any(i => SymbolEqualityComparer.Default.Equals(i, iNotifyPropertyChangedSymbol)))
+            {
+                descriptor = DuplicateINotifyPropertyChangedInterfaceForINotifyPropertyChangedAttributeError;
+
+                return false;
+            }
+
+            descriptor = null;
+
+            return true;
+        }
+
+        /// <inheritdoc/>
+        protected override IEnumerable<MemberDeclarationSyntax> FilterDeclaredMembers(
+            GeneratorExecutionContext context,
+            AttributeData attributeData,
+            ClassDeclarationSyntax classDeclaration,
+            INamedTypeSymbol classDeclarationSymbol,
+            ClassDeclarationSyntax sourceDeclaration)
+        {
+            // If requested, only include the event and the basic methods to raise it, but not the additional helpers
+            if (attributeData.HasNamedArgument("IncludeAdditionalHelperMethods", false))
+            {
+                return sourceDeclaration.Members.Where(static member =>
+                {
+                    return member
+                        is EventFieldDeclarationSyntax
+                        or MethodDeclarationSyntax { Identifier: { ValueText: "OnPropertyChanged" } };
+                });
+            }
+
+            return sourceDeclaration.Members;
+        }
+    }
+}

Microsoft.Toolkit.Mvvm.SourceGenerators/ComponentModel/ObservableObjectGenerator.cs

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+// 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.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using static Microsoft.Toolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
+
+namespace Microsoft.Toolkit.Mvvm.SourceGenerators
+{
+    /// <summary>
+    /// A source generator for the <c>ObservableObjectAttribute</c> type.
+    /// </summary>
+    [Generator]
+    public sealed class ObservableObjectGenerator : TransitiveMembersGenerator
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ObservableObjectGenerator"/> class.
+        /// </summary>
+        public ObservableObjectGenerator()
+            : base("Microsoft.Toolkit.Mvvm.ComponentModel.ObservableObjectAttribute")
+        {
+        }
+
+        /// <inheritdoc/>
+        protected override DiagnosticDescriptor TargetTypeErrorDescriptor => ObservableObjectGeneratorError;
+
+        /// <inheritdoc/>
+        protected override bool ValidateTargetType(
+            GeneratorExecutionContext context,
+            AttributeData attributeData,
+            ClassDeclarationSyntax classDeclaration,
+            INamedTypeSymbol classDeclarationSymbol,
+            [NotNullWhen(false)] out DiagnosticDescriptor? descriptor)
+        {
+            INamedTypeSymbol
+                iNotifyPropertyChangedSymbol = context.Compilation.GetTypeByMetadataName("System.ComponentModel.INotifyPropertyChanged")!,
+                iNotifyPropertyChangingSymbol = context.Compilation.GetTypeByMetadataName("System.ComponentModel.INotifyPropertyChanging")!;
+
+            // Check if the type already implements INotifyPropertyChanged...
+            if (classDeclarationSymbol.AllInterfaces.Any(i => SymbolEqualityComparer.Default.Equals(i, iNotifyPropertyChangedSymbol)))
+            {
+                descriptor = DuplicateINotifyPropertyChangedInterfaceForObservableObjectAttributeError;
+
+                return false;
+            }
+
+            // ...or INotifyPropertyChanging
+            if (classDeclarationSymbol.AllInterfaces.Any(i => SymbolEqualityComparer.Default.Equals(i, iNotifyPropertyChangingSymbol)))
+            {
+                descriptor = DuplicateINotifyPropertyChangingInterfaceForObservableObjectAttributeError;
+
+                return false;
+            }
+
+            descriptor = null;
+
+            return true;
+        }
+    }
+}

Microsoft.Toolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.SyntaxReceiver.cs

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+// 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.Generic;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace Microsoft.Toolkit.Mvvm.SourceGenerators
+{
+    /// <inheritdoc cref="ObservablePropertyGenerator"/>
+    public sealed partial class ObservablePropertyGenerator
+    {
+        /// <summary>
+        /// An <see cref="ISyntaxContextReceiver"/> that selects candidate nodes to process.
+        /// </summary>
+        private sealed class SyntaxReceiver : ISyntaxContextReceiver
+        {
+            /// <summary>
+            /// The list of info gathered during exploration.
+            /// </summary>
+            private readonly List<Item> gatheredInfo = new();
+
+            /// <summary>
+            /// Gets the collection of gathered info to process.
+            /// </summary>
+            public IReadOnlyCollection<Item> GatheredInfo => this.gatheredInfo;
+
+            /// <inheritdoc/>
+            public void OnVisitSyntaxNode(GeneratorSyntaxContext context)
+            {
+                if (context.Node is FieldDeclarationSyntax { AttributeLists: { Count: > 0 } } fieldDeclaration &&
+                    context.SemanticModel.Compilation.GetTypeByMetadataName("Microsoft.Toolkit.Mvvm.ComponentModel.ObservablePropertyAttribute") is INamedTypeSymbol attributeSymbol)
+                {
+                    SyntaxTriviaList leadingTrivia = fieldDeclaration.GetLeadingTrivia();
+
+                    foreach (VariableDeclaratorSyntax variableDeclarator in fieldDeclaration.Declaration.Variables)
+                    {
+                        if (context.SemanticModel.GetDeclaredSymbol(variableDeclarator) is IFieldSymbol fieldSymbol &&
+                            fieldSymbol.GetAttributes().Any(a => SymbolEqualityComparer.Default.Equals(a.AttributeClass, attributeSymbol)))
+                        {
+                            this.gatheredInfo.Add(new Item(leadingTrivia, fieldSymbol));
+                        }
+                    }
+                }
+            }
+
+            /// <summary>
+            /// A model for a group of item representing a discovered type to process.
+            /// </summary>
+            /// <param name="LeadingTrivia">The leading trivia for the field declaration.</param>
+            /// <param name="FieldSymbol">The <see cref="IFieldSymbol"/> instance for the target field.</param>
+            public sealed record Item(SyntaxTriviaList LeadingTrivia, IFieldSymbol FieldSymbol);
+        }
+    }
+}