From 40008ca9441275cf8a3d5b790215ffc5046f6eb7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A9rald=20Barr=C3=A9?= <git@meziantou.net>
Date: Sat, 21 Sep 2024 15:30:40 -0400
Subject: [PATCH] Disable ussage of List.Find in .NET 9

---
 .../Internals/CompilationExtensions.cs        |  7 ++++
 .../Rules/OptimizeLinqUsageAnalyzer.cs        | 34 +++++++++++--------
 .../Helpers/ProjectBuilder.Validation.cs      |  2 +-
 ...eLinqUsageAnalyzerUseDirectMethodsTests.cs | 21 ++++++++++++
 4 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/src/Meziantou.Analyzer/Internals/CompilationExtensions.cs b/src/Meziantou.Analyzer/Internals/CompilationExtensions.cs
index 145092577..45165810a 100644
--- a/src/Meziantou.Analyzer/Internals/CompilationExtensions.cs
+++ b/src/Meziantou.Analyzer/Internals/CompilationExtensions.cs
@@ -8,6 +8,13 @@ namespace Meziantou.Analyzer;
 
 internal static class CompilationExtensions
 {
+    public static bool IsNet9OrGreater(this Compilation compilation)
+    {
+        var type = compilation.GetSpecialType(SpecialType.System_Object);
+        var version = type.ContainingAssembly.Identity.Version;
+        return version.Major >= 9;
+    }
+
 #if ROSLYN_3_8
     public static ImmutableArray<INamedTypeSymbol> GetTypesByMetadataName(this Compilation compilation, string typeMetadataName)
     {
diff --git a/src/Meziantou.Analyzer/Rules/OptimizeLinqUsageAnalyzer.cs b/src/Meziantou.Analyzer/Rules/OptimizeLinqUsageAnalyzer.cs
index 280eee770..abd0ded3f 100755
--- a/src/Meziantou.Analyzer/Rules/OptimizeLinqUsageAnalyzer.cs
+++ b/src/Meziantou.Analyzer/Rules/OptimizeLinqUsageAnalyzer.cs
@@ -287,24 +287,28 @@ private void UseFindInsteadOfFirstOrDefault(OperationAnalysisContext context, II
             if (firstArgumentType is null)
                 return;
 
-            if (firstArgumentType.OriginalDefinition.IsEqualTo(ListOfTSymbol))
-            {
-                ImmutableDictionary<string, string?> properties;
-                var predicateArgument = operation.Arguments[1].Value;
-                if (predicateArgument is IDelegateCreationOperation)
-                {
-                    properties = CreateProperties(OptimizeLinqUsageData.UseFindMethod);
-                }
-                else
-                {
-                    if (!context.Options.GetConfigurationValue(operation, ListMethodsRule.Id + ".report_when_conversion_needed", defaultValue: false))
-                        return;
+            if (!firstArgumentType.OriginalDefinition.IsEqualTo(ListOfTSymbol))
+                return;
 
-                    properties = CreateProperties(OptimizeLinqUsageData.UseFindMethodWithConversion);
-                }
+            // https://github.com/dotnet/runtime/issues/108064
+            if (context.Compilation.IsNet9OrGreater())
+                return;
+
+            ImmutableDictionary<string, string?> properties;
+            var predicateArgument = operation.Arguments[1].Value;
+            if (predicateArgument is IDelegateCreationOperation)
+            {
+                properties = CreateProperties(OptimizeLinqUsageData.UseFindMethod);
+            }
+            else
+            {
+                if (!context.Options.GetConfigurationValue(operation, ListMethodsRule.Id + ".report_when_conversion_needed", defaultValue: false))
+                    return;
 
-                context.ReportDiagnostic(ListMethodsRule, properties, operation, DiagnosticInvocationReportOptions.ReportOnMember, "Find()", operation.TargetMethod.Name);
+                properties = CreateProperties(OptimizeLinqUsageData.UseFindMethodWithConversion);
             }
+
+            context.ReportDiagnostic(ListMethodsRule, properties, operation, DiagnosticInvocationReportOptions.ReportOnMember, "Find()", operation.TargetMethod.Name);
         }
 
         private void UseTrueForAllInsteadOfAll(OperationAnalysisContext context, IInvocationOperation operation)
diff --git a/tests/Meziantou.Analyzer.Test/Helpers/ProjectBuilder.Validation.cs b/tests/Meziantou.Analyzer.Test/Helpers/ProjectBuilder.Validation.cs
index df94c623d..967be2f17 100755
--- a/tests/Meziantou.Analyzer.Test/Helpers/ProjectBuilder.Validation.cs
+++ b/tests/Meziantou.Analyzer.Test/Helpers/ProjectBuilder.Validation.cs
@@ -191,7 +191,7 @@ private Task<Project> CreateProject()
                 break;
 
             case TargetFramework.Net9_0:
-                AddNuGetReference("Microsoft.NETCore.App.Ref", "9.0.0-preview.4.24266.19", "ref/net9.0/");
+                AddNuGetReference("Microsoft.NETCore.App.Ref", "9.0.0-rc.1.24431.7", "ref/net9.0/");
                 break;
 
             case TargetFramework.AspNetCore5_0:
diff --git a/tests/Meziantou.Analyzer.Test/Rules/OptimizeLinqUsageAnalyzerUseDirectMethodsTests.cs b/tests/Meziantou.Analyzer.Test/Rules/OptimizeLinqUsageAnalyzerUseDirectMethodsTests.cs
index 4e3f36156..0bc713fc9 100755
--- a/tests/Meziantou.Analyzer.Test/Rules/OptimizeLinqUsageAnalyzerUseDirectMethodsTests.cs
+++ b/tests/Meziantou.Analyzer.Test/Rules/OptimizeLinqUsageAnalyzerUseDirectMethodsTests.cs
@@ -14,6 +14,27 @@ private static ProjectBuilder CreateProjectBuilder()
             .WithCodeFixProvider<OptimizeLinqUsageFixer>();
     }
 
+    [Fact]
+    public Task FirstOrDefaultAsync_Net9()
+        => CreateProjectBuilder()
+              .WithTargetFramework(TargetFramework.Net9_0)
+              .WithSourceCode("""
+                using System.Linq;
+                class Test
+                {
+                    public Test()
+                    {
+                        var enumerable = System.Linq.Enumerable.Empty<int>();
+                        var list = new System.Collections.Generic.List<int>();
+                        list.FirstOrDefault();
+                        list.FirstOrDefault(x => x == 0);
+                        enumerable.FirstOrDefault();
+                        enumerable.FirstOrDefault(x => x == 0);
+                    }
+                }
+                """)
+              .ValidateAsync();
+
     [Fact]
     public async Task FirstOrDefaultAsync()
     {