From 1262b16f593352ef82f5d085e788cebf24bfbcb7 Mon Sep 17 00:00:00 2001
From: David Wengier <david.wengier@microsoft.com>
Date: Sat, 6 Nov 2021 09:27:19 +1100
Subject: [PATCH] Don't crash Use ExpressionBody on local functions in top
 level statements (#57571)

---
 .../UseExpressionBodyCodeFixProvider.cs       |  3 +-
 ...ssionBodyForLocalFunctionsAnalyzerTests.cs | 67 +++++++++++++++++++
 2 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/src/Analyzers/CSharp/CodeFixes/UseExpressionBody/UseExpressionBodyCodeFixProvider.cs b/src/Analyzers/CSharp/CodeFixes/UseExpressionBody/UseExpressionBodyCodeFixProvider.cs
index 10f7e8738ac58..eee0034fba488 100644
--- a/src/Analyzers/CSharp/CodeFixes/UseExpressionBody/UseExpressionBodyCodeFixProvider.cs
+++ b/src/Analyzers/CSharp/CodeFixes/UseExpressionBody/UseExpressionBodyCodeFixProvider.cs
@@ -8,7 +8,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Composition;
-using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -90,7 +89,7 @@ private static void AddEdits(
         {
             var declarationLocation = diagnostic.AdditionalLocations[0];
             var helper = _helpers.Single(h => h.DiagnosticId == diagnostic.Id);
-            var declaration = declarationLocation.FindNode(cancellationToken);
+            var declaration = declarationLocation.FindNode(getInnermostNodeForTie: true, cancellationToken);
             var useExpressionBody = diagnostic.Properties.ContainsKey(nameof(UseExpressionBody));
 
             var updatedDeclaration = helper.Update(semanticModel, declaration, useExpressionBody)
diff --git a/src/Analyzers/CSharp/Tests/UseExpressionBody/UseExpressionBodyForLocalFunctionsAnalyzerTests.cs b/src/Analyzers/CSharp/Tests/UseExpressionBody/UseExpressionBodyForLocalFunctionsAnalyzerTests.cs
index 2ae402fdc5b2e..f0667646dd8fb 100644
--- a/src/Analyzers/CSharp/Tests/UseExpressionBody/UseExpressionBodyForLocalFunctionsAnalyzerTests.cs
+++ b/src/Analyzers/CSharp/Tests/UseExpressionBody/UseExpressionBodyForLocalFunctionsAnalyzerTests.cs
@@ -4,11 +4,13 @@
 
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeStyle;
+using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.CodeStyle;
 using Microsoft.CodeAnalysis.CSharp.UseExpressionBody;
 using Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Microsoft.CodeAnalysis.Testing;
+using Roslyn.Test.Utilities;
 using Xunit;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.UseExpressionBody
@@ -829,5 +831,70 @@ void Bar()
 }";
             await TestWithUseExpressionBody(code, fixedCode);
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseExpressionBody)]
+        [WorkItem(57570, "https://github.com/dotnet/roslyn/issues/57570")]
+        public async Task TestUseExpressionBodyTopLevelStatment()
+        {
+            await new VerifyCS.Test
+            {
+                TestState =
+                {
+                    OutputKind = OutputKind.ConsoleApplication,
+                    Sources =
+                    {
+                        @"
+{|IDE0061:int Bar(int x)
+{
+    return x;
+}|}
+"
+                    },
+                },
+                FixedState =
+                {
+                    Sources =
+                    {
+                        @"
+int Bar(int x) => x;
+"
+                    },
+                },
+                LanguageVersion = LanguageVersion.CSharp9,
+                Options = { { CSharpCodeStyleOptions.PreferExpressionBodiedLocalFunctions, ExpressionBodyPreference.WhenPossible } },
+            }.RunAsync();
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseExpressionBody)]
+        [WorkItem(57570, "https://github.com/dotnet/roslyn/issues/57570")]
+        public async Task TestUseBlockBodyTopLevelStatment()
+        {
+            await new VerifyCS.Test
+            {
+                TestState =
+                {
+                    OutputKind = OutputKind.ConsoleApplication,
+                    Sources =
+                    {
+                        @"
+{|IDE0061:int Bar(int x) => x;|}
+"
+                    },
+                },
+                FixedState =
+                {
+                    Sources =
+                    {
+                        @"
+int Bar(int x)
+{
+    return x;
+}"
+                    },
+                },
+                LanguageVersion = LanguageVersion.CSharp9,
+                Options = { { CSharpCodeStyleOptions.PreferExpressionBodiedLocalFunctions, ExpressionBodyPreference.Never } },
+            }.RunAsync();
+        }
     }
 }