From 928e332e4b1c19051afc20af8a17e8450ab4bd97 Mon Sep 17 00:00:00 2001
From: "Steven T. Cramer" <Steven.Cramer@TimeWarp.Enterprises>
Date: Tue, 13 Aug 2024 02:06:07 +0700
Subject: [PATCH 1/2] Add anlyzer to make sure States are declared correctly.

---
 .../AnalyzerReleases.Unshipped.md             |  1 +
 .../StateInheritanceAnalyzer.cs               | 52 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 Source/TimeWarp.State.Analyzer/StateInheritanceAnalyzer.cs

diff --git a/Source/TimeWarp.State.Analyzer/AnalyzerReleases.Unshipped.md b/Source/TimeWarp.State.Analyzer/AnalyzerReleases.Unshipped.md
index db712857e..92c2decd8 100644
--- a/Source/TimeWarp.State.Analyzer/AnalyzerReleases.Unshipped.md
+++ b/Source/TimeWarp.State.Analyzer/AnalyzerReleases.Unshipped.md
@@ -5,5 +5,6 @@
 
 Rule ID | Category | Severity | Notes
 --------|----------|----------|-------
+StateInheritanceRule | Design | Error | StateInheritanceAnalyzer
 TW0001 | TimeWarp.State | Error | TimeWarpStateActionAnalyzer
 TWD001 | Debug | Info | TimeWarpStateActionAnalyzer
diff --git a/Source/TimeWarp.State.Analyzer/StateInheritanceAnalyzer.cs b/Source/TimeWarp.State.Analyzer/StateInheritanceAnalyzer.cs
new file mode 100644
index 000000000..b6c4e6ba0
--- /dev/null
+++ b/Source/TimeWarp.State.Analyzer/StateInheritanceAnalyzer.cs
@@ -0,0 +1,52 @@
+namespace TimeWarp.State.Analyzer;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+using System.Collections.Immutable;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public class StateInheritanceAnalyzer : DiagnosticAnalyzer
+{
+    public const string DiagnosticId = "StateInheritanceRule";
+
+    private static readonly LocalizableString Title = "Incorrect State<T> inheritance";
+    private static readonly LocalizableString MessageFormat = "The type argument for State<T> must be the derived class itself";
+    private static readonly LocalizableString Description = "When inheriting from State<T>, T must be the name of the derived class.";
+    private const string Category = "Design";
+
+    private static readonly DiagnosticDescriptor Rule = new(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Error, isEnabledByDefault: true, description: Description);
+
+    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get { return ImmutableArray.Create(Rule); } }
+
+    public override void Initialize(AnalysisContext context)
+    {
+        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+        context.EnableConcurrentExecution();
+        context.RegisterSyntaxNodeAction(AnalyzeNode, SyntaxKind.ClassDeclaration);
+    }
+
+    private static void AnalyzeNode(SyntaxNodeAnalysisContext context)
+    {
+        var classDeclaration = (ClassDeclarationSyntax)context.Node;
+        BaseTypeSyntax? baseType = classDeclaration.BaseList?.Types.FirstOrDefault();
+        
+        if (baseType == null) return;
+
+        var baseTypeSymbol = context.SemanticModel.GetSymbolInfo(baseType.Type).Symbol as INamedTypeSymbol;
+        if (baseTypeSymbol == null || !baseTypeSymbol.Name.Equals("State")) return;
+
+        ITypeSymbol? typeArg = baseTypeSymbol.TypeArguments.FirstOrDefault();
+        if (typeArg == null) return;
+
+        INamedTypeSymbol? derivedTypeSymbol = context.SemanticModel.GetDeclaredSymbol(classDeclaration);
+        if (derivedTypeSymbol == null) return;
+
+        if (!SymbolEqualityComparer.Default.Equals(typeArg, derivedTypeSymbol))
+        {
+            var diagnostic = Diagnostic.Create(Rule, classDeclaration.Identifier.GetLocation());
+            context.ReportDiagnostic(diagnostic);
+        }
+    }
+}

From cdd18b71cee3b3517bbf6795bc7806280472da28 Mon Sep 17 00:00:00 2001
From: "Steven T. Cramer" <Steven.Cramer@TimeWarp.Enterprises>
Date: Tue, 13 Aug 2024 02:06:52 +0700
Subject: [PATCH 2/2] Bump version

---
 Directory.Build.props | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index f97e7ca36..7b2a5e57b 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -1,7 +1,7 @@
 <Project>
   <!-- Set common properties regarding assembly information and nuget packages -->
   <PropertyGroup>
-    <TimeWarpStateVersion>11.0.0-beta.81+8.0.303</TimeWarpStateVersion>
+    <TimeWarpStateVersion>11.0.0-beta.82+8.0.303</TimeWarpStateVersion>
     <Authors>Steven T. Cramer</Authors>
     <Product>TimeWarp State</Product>
     <PackageVersion>$(TimeWarpStateVersion)</PackageVersion>