Fix unused type parameter (RCS1164) (#1196)

ChangeLog.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix [RCS1164](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1164) ([#1196](https://github.com/JosefPihrt/Roslynator/pull/1196)).
+
 ## [4.5.0] - 2023-08-27
 
 ### Added

src/Analyzers/CSharp/Analysis/UnusedParameter/UnusedParameterWalker.cs

@@ -182,7 +182,7 @@ public override void VisitBracketedParameterList(BracketedParameterListSyntax no
 
     public override void VisitParameterList(ParameterListSyntax node)
     {
-        if (node.IsParentKind(SyntaxKind.MethodDeclaration, SyntaxKind.LocalFunctionStatement))
+        if (node.IsParentKind(SyntaxKind.MethodDeclaration, SyntaxKind.LocalFunctionStatement, SyntaxKind.ParenthesizedLambdaExpression))
             base.VisitParameterList(node);
     }
 

src/Tests/Analyzers.Tests/RCS1164UnusedTypeParameterTests.cs

@@ -0,0 +1,45 @@
+// Copyright (c) Josef Pihrt and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Roslynator.CSharp.CodeFixes;
+using Roslynator.Testing.CSharp;
+using Xunit;
+
+namespace Roslynator.CSharp.Analysis.Tests;
+
+public class RCS1164UnusedTypeParameterTests : AbstractCSharpDiagnosticVerifier<UnusedParameter.UnusedParameterAnalyzer, UnusedParameterCodeFixProvider>
+{
+    public override DiagnosticDescriptor Descriptor { get; } = DiagnosticRules.UnusedTypeParameter;
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UnusedTypeParameter)]
+    public async Task TestNoDiagnostic_DependencyPropertyEventArgs()
+    {
+        await VerifyNoDiagnosticAsync(@"
+using System;
+
+public static class TestClass
+{
+    public static void RunDelegate<T>(object arg)
+    {
+        RunDelegate(arg, (T arg) =>
+        {
+            if (arg is string stringArg)
+            {
+                Console.WriteLine(stringArg);
+            }
+        }
+        );
+    }
+
+    private static void RunDelegate(
+        object arg,
+        Delegate _delegate
+        )
+    {
+        _delegate.DynamicInvoke(arg);
+    }
+}
+");
+    }
+}