Merge pull request #36054 from sharwell/avoid-rename

Avoid renaming methods that don't change return type

src/EditorFeatures/CSharpTest/Diagnostics/MakeMethodAsynchronous/MakeMethodAsynchronousTests.cs

@@ -17,6 +17,7 @@ internal override (DiagnosticAnalyzer, CodeFixProvider) CreateDiagnosticProvider
             => (null, new CSharpMakeMethodAsynchronousCodeFixProvider());
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AwaitInVoidMethodWithModifiers()
         {
             var initial =
@@ -37,7 +38,7 @@ public static void Test()
 
 class Program
 {
-    public static async void TestAsync()
+    public static async void Test()
     {
         await Task.Delay(1);
     }
@@ -81,6 +82,7 @@ public static async Task Main()
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
         [WorkItem(26312, "https://github.com/dotnet/roslyn/issues/26312")]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AwaitInVoidMainMethodWithModifiers_NotEntryPoint()
         {
             var initial =
@@ -101,7 +103,7 @@ public void Main()
 
 class Program
 {
-    public async void MainAsync()
+    public async void Main()
     {
         await Task.Delay(1);
     }
@@ -139,6 +141,7 @@ public static async Task TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AwaitInTaskMethodNoModifiers()
         {
             var initial =
@@ -159,7 +162,7 @@ Task Test()
 
 class Program 
 {
-    async Task TestAsync() 
+    async Task Test() 
     {
         await Task.Delay(1);
     }
@@ -168,6 +171,7 @@ async Task TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AwaitInTaskMethodWithModifiers()
         {
             var initial =
@@ -188,7 +192,7 @@ class Program
 
 class Program
 {
-    public/*Comment*/static/*Comment*/async Task/*Comment*/TestAsync()
+    public/*Comment*/static/*Comment*/async Task/*Comment*/Test()
     {
         await Task.Delay(1);
     }
@@ -257,6 +261,7 @@ static void Main(string[] args)
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod()
         {
             var initial =
@@ -273,7 +278,7 @@ void Test()
 @"using System.Threading.Tasks;
 class Program
 {
-    async void TestAsync()
+    async void Test()
     {
         await Task.Delay(1);
     }
@@ -282,6 +287,7 @@ async void TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod2()
         {
             var initial =
@@ -298,7 +304,7 @@ Task Test()
 @"using System.Threading.Tasks;
 class Program
 {
-    async Task TestAsync()
+    async Task Test()
     {
         await Task.Delay(1);
     }
@@ -307,6 +313,7 @@ async Task TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod3()
         {
             var initial =
@@ -323,7 +330,7 @@ Task<int> Test()
 @"using System.Threading.Tasks;
 class Program
 {
-    async Task<int> TestAsync()
+    async Task<int> Test()
     {
         await Task.Delay(1);
     }
@@ -357,6 +364,7 @@ async Task<int> TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod5()
         {
             var initial =
@@ -371,7 +379,7 @@ void Test()
             var expected =
 @"class Program
 {
-    async void TestAsync()
+    async void Test()
     {
         await Task.Delay(1);
     }
@@ -380,6 +388,7 @@ async void TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod6()
         {
             var initial =
@@ -394,7 +403,7 @@ Task Test()
             var expected =
 @"class Program
 {
-    async Task TestAsync()
+    async Task Test()
     {
         await Task.Delay(1);
     }
@@ -403,6 +412,7 @@ async Task TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInNonAsyncMethod7()
         {
             var initial =
@@ -417,7 +427,7 @@ Task<int> Test()
             var expected =
 @"class Program
 {
-    async Task<int> TestAsync()
+    async Task<int> Test()
     {
         await Task.Delay(1);
     }
@@ -714,6 +724,7 @@ async IAsyncEnumerator<int> TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInIAsyncEnumerableMethod()
         {
             var initial =
@@ -733,7 +744,7 @@ IAsyncEnumerable<int> Test()
 using System.Collections.Generic;
 class Program
 {
-    async IAsyncEnumerable<int> TestAsync()
+    async IAsyncEnumerable<int> Test()
     {
         yield return 1;
         await Task.Delay(1);
@@ -743,6 +754,7 @@ async IAsyncEnumerable<int> TestAsync()
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task BadAwaitInIAsyncEnumeratorMethod()
         {
             var initial =
@@ -762,7 +774,7 @@ IAsyncEnumerator<int> Test()
 using System.Collections.Generic;
 class Program
 {
-    async IAsyncEnumerator<int> TestAsync()
+    async IAsyncEnumerator<int> Test()
     {
         yield return 1;
         await Task.Delay(1);
@@ -927,6 +939,7 @@ static async void Main()
 
         [WorkItem(17470, "https://github.com/dotnet/roslyn/issues/17470")]
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AwaitInValueTaskMethod()
         {
             var initial =
@@ -959,7 +972,7 @@ struct ValueTask<T>
 
 class Program 
 {
-    async ValueTask<int> TestAsync() 
+    async ValueTask<int> Test() 
     {
         await Task.Delay(1);
     }
@@ -1010,6 +1023,7 @@ async Task<int> M3Async()
 
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
         [WorkItem(14133, "https://github.com/dotnet/roslyn/issues/14133")]
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
         public async Task AddAsyncInLocalFunctionKeepVoidReturn()
         {
             await TestInRegularAndScriptAsync(
@@ -1036,7 +1050,7 @@ class C
 {
     public void M1()
     {
-        async void M2Async()
+        async void M2()
         {
             await M3Async();
         }
@@ -1051,13 +1065,14 @@ async Task<int> M3Async()
         }
 
         [Theory]
-        [InlineData(0, "void", "Task")]
-        [InlineData(1, "void", "void")]
-        [InlineData(0, "int", "Task<int>")]
-        [InlineData(0, "Task", "Task")]
+        [InlineData(0, "void", "Task", "M2Async")]
+        [InlineData(1, "void", "void", "M2")]
+        [InlineData(0, "int", "Task<int>", "M2Async")]
+        [InlineData(0, "Task", "Task", "M2")]
         [Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
         [WorkItem(18307, "https://github.com/dotnet/roslyn/issues/18307")]
-        public async Task AddAsyncInLocalFunctionKeepsTrivia(int codeFixIndex, string initialReturn, string expectedReturn)
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
+        public async Task AddAsyncInLocalFunctionKeepsTrivia(int codeFixIndex, string initialReturn, string expectedReturn, string expectedName)
         {
             await TestInRegularAndScriptAsync(
 $@"using System.Threading.Tasks;
@@ -1085,7 +1100,7 @@ class C
     public void M1()
     {{
         // Leading trivia
-        /*1*/ async {expectedReturn} /*2*/ M2Async/*3*/() /*4*/
+        /*1*/ async {expectedReturn} /*2*/ {expectedName}/*3*/() /*4*/
         {{
             await M3Async();
         }}
@@ -1100,13 +1115,14 @@ async Task<int> M3Async()
         }
 
         [Theory]
-        [InlineData("", 0, "Task")]
-        [InlineData("", 1, "void")]
-        [InlineData("public", 0, "Task")]
-        [InlineData("public", 1, "void")]
+        [InlineData("", 0, "Task", "M2Async")]
+        [InlineData("", 1, "void", "M2")]
+        [InlineData("public", 0, "Task", "M2Async")]
+        [InlineData("public", 1, "void", "M2")]
         [Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)]
         [WorkItem(18307, "https://github.com/dotnet/roslyn/issues/18307")]
-        public async Task AddAsyncKeepsTrivia(string modifiers, int codeFixIndex, string expectedReturn)
+        [WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")]
+        public async Task AddAsyncKeepsTrivia(string modifiers, int codeFixIndex, string expectedReturn, string expectedName)
         {
             await TestInRegularAndScriptAsync(
 $@"using System.Threading.Tasks;
@@ -1129,7 +1145,7 @@ async Task<int> M3Async()
 class C
 {{
     // Leading trivia
-    {modifiers}/*1*/ async {expectedReturn} /*2*/ M2Async/*3*/() /*4*/
+    {modifiers}/*1*/ async {expectedReturn} /*2*/ {expectedName}/*3*/() /*4*/
     {{
         await M3Async();
     }}

src/EditorFeatures/VisualBasicTest/Diagnostics/MakeMethodAsynchronous/MakeMethodAsynchronousTests.vb

@@ -13,6 +13,7 @@ Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.Diagnostics.MakeMe
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestAwaitInSubNoModifiers() As Task
             Await TestInRegularAndScriptAsync(
 "Imports System
@@ -25,7 +26,7 @@ End Module",
 "Imports System
 Imports System.Threading.Tasks
 Module Program
-    Async Sub TestAsync()
+    Async Sub Test()
         Await Task.Delay(1) 
  End Sub
 End Module",
@@ -33,6 +34,7 @@ End Module",
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestAwaitInSubWithModifiers() As Task
             Await TestInRegularAndScriptAsync(
 "Imports System
@@ -45,7 +47,7 @@ End Module",
 "Imports System
 Imports System.Threading.Tasks
 Module Program
-    Public Shared Async Sub TestAsync()
+    Public Shared Async Sub Test()
         Await Task.Delay(1) 
  End Sub
 End Module",
@@ -137,6 +139,7 @@ Module Program
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncMethod() As Task
             Dim initial =
 <ModuleDeclaration>
@@ -146,7 +149,7 @@ Module Program
 </ModuleDeclaration>
             Dim expected =
 <ModuleDeclaration>
-Async Function rtrtAsync() As Task
+Async Function rtrt() As Task
         Await Nothing
     End Function
 </ModuleDeclaration>
@@ -154,6 +157,7 @@ Async Function rtrtAsync() As Task
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncVoidMethod() As Task
             Dim initial =
 <ModuleDeclaration>
@@ -163,7 +167,7 @@ Async Function rtrtAsync() As Task
 </ModuleDeclaration>
             Dim expected =
 <ModuleDeclaration>
-Async Sub rtrtAsync()
+Async Sub rtrt()
         Await Nothing
     End Sub
 </ModuleDeclaration>
@@ -188,6 +192,7 @@ Async Function rtrtAsync() As Threading.Tasks.Task
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncFunction() As Task
             Dim initial =
 <ModuleDeclaration>
@@ -197,7 +202,7 @@ Async Function rtrtAsync() As Threading.Tasks.Task
 </ModuleDeclaration>
             Dim expected =
 <ModuleDeclaration>
-Async Function rtrtAsync() As Task
+Async Function rtrt() As Task
         Await Nothing
     End Function
 </ModuleDeclaration>
@@ -205,6 +210,7 @@ Async Function rtrtAsync() As Task
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncFunction2() As Task
             Dim initial =
 <ModuleDeclaration>
@@ -214,7 +220,7 @@ Async Function rtrtAsync() As Task
 </ModuleDeclaration>
             Dim expected =
 <ModuleDeclaration>
-Async Function rtrtAsync() As Task(Of Integer)
+Async Function rtrt() As Task(Of Integer)
         Await Nothing
     End Function
 </ModuleDeclaration>
@@ -239,6 +245,7 @@ Async Function rtrtAsync() As Threading.Tasks.Task(Of Integer)
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncFunction4() As Task
             Dim initial =
 <File>
@@ -251,7 +258,7 @@ End Class
             Dim expected =
 <File>
 Class Program
-    Async Function rtrtAsync() As Task
+    Async Function rtrt() As Task
         Await Nothing
     End Function
 End Class
@@ -260,6 +267,7 @@ End Class
         End Function
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsMakeMethodAsynchronous)>
+        <WorkItem(33082, "https://github.com/dotnet/roslyn/issues/33082")>
         Public Async Function TestBadAwaitInNonAsyncFunction5() As Task
             Dim initial =
 <File>
@@ -272,7 +280,7 @@ End Class
             Dim expected =
 <File>
 Class Program
-    Async Function rtrtAsync() As Task(Of Integer)
+    Async Function rtrt() As Task(Of Integer)
         Await Nothing
     End Function
 End Class

src/Features/CSharp/Portable/MakeMethodAsynchronous/CSharpMakeMethodAsynchronousCodeFixProvider.cs

@@ -44,6 +44,12 @@ protected override string GetMakeAsyncVoidFunctionResource()
         protected override bool IsAsyncSupportingFunctionSyntax(SyntaxNode node)
             => node.IsAsyncSupportingFunctionSyntax();
 
+        protected override bool IsAsyncReturnType(ITypeSymbol type, KnownTypes knownTypes)
+        {
+            return IsIAsyncEnumerableOrEnumerator(type, knownTypes)
+                || IsTaskLike(type, knownTypes);
+        }
+
         protected override SyntaxNode AddAsyncTokenAndFixReturnType(
             bool keepVoid, IMethodSymbol methodSymbolOpt, SyntaxNode node,
             KnownTypes knownTypes)

src/Features/Core/Portable/MakeMethodAsynchronous/AbstractMakeMethodAsynchronousCodeFixProvider.cs

@@ -17,6 +17,8 @@ internal abstract partial class AbstractMakeMethodAsynchronousCodeFixProvider :
     {
         protected abstract bool IsAsyncSupportingFunctionSyntax(SyntaxNode node);
 
+        protected abstract bool IsAsyncReturnType(ITypeSymbol type, KnownTypes knownTypes);
+
         protected abstract SyntaxNode AddAsyncTokenAndFixReturnType(
             bool keepVoid, IMethodSymbol methodSymbolOpt, SyntaxNode node,
             KnownTypes knownTypes);
@@ -93,17 +95,49 @@ private bool IsLikelyEntryPointName(string name, Document document)
             // if it has the 'Async' suffix, and remove that suffix if so.
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
             var methodSymbolOpt = semanticModel.GetDeclaredSymbol(node) as IMethodSymbol;
+            var compilation = await document.Project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
+            var knownTypes = new KnownTypes(compilation);
 
-            bool isOrdinaryOrLocalFunction = methodSymbolOpt.IsOrdinaryMethodOrLocalFunction();
-            if (isOrdinaryOrLocalFunction && !methodSymbolOpt.Name.EndsWith(AsyncSuffix) && !isEntryPoint)
+            if (NeedsRename(this, methodSymbolOpt, keepVoid, isEntryPoint, in knownTypes))
             {
                 return await RenameThenAddAsyncTokenAsync(
-                    keepVoid, document, node, methodSymbolOpt, cancellationToken).ConfigureAwait(false);
+                    keepVoid, document, node, methodSymbolOpt, knownTypes, cancellationToken).ConfigureAwait(false);
             }
             else
             {
                 return await AddAsyncTokenAsync(
-                    keepVoid, document, methodSymbolOpt, node, cancellationToken).ConfigureAwait(false);
+                    keepVoid, document, methodSymbolOpt, knownTypes, node, cancellationToken).ConfigureAwait(false);
+            }
+
+            static bool NeedsRename(AbstractMakeMethodAsynchronousCodeFixProvider @this, IMethodSymbol methodSymbol, bool keepVoid, bool isEntryPoint, in KnownTypes knownTypes)
+            {
+                if (!methodSymbol.IsOrdinaryMethodOrLocalFunction())
+                {
+                    // We don't need to rename methods that don't have a name
+                    return false;
+                }
+
+                if (methodSymbol.Name.EndsWith(AsyncSuffix))
+                {
+                    // We don't need to rename methods that already have an Async suffix
+                    return false;
+                }
+
+                if (isEntryPoint)
+                {
+                    // We don't need to rename entry point methods
+                    return false;
+                }
+
+                // Only rename if the return type will change
+                if (methodSymbol.ReturnsVoid)
+                {
+                    return !keepVoid;
+                }
+                else
+                {
+                    return !@this.IsAsyncReturnType(methodSymbol.ReturnType, knownTypes);
+                }
             }
         }
 
@@ -115,8 +149,12 @@ private SyntaxNode GetContainingFunction(Diagnostic diagnostic, CancellationToke
         }
 
         private async Task<Solution> RenameThenAddAsyncTokenAsync(
-            bool keepVoid, Document document, SyntaxNode node,
-            IMethodSymbol methodSymbol, CancellationToken cancellationToken)
+            bool keepVoid,
+            Document document,
+            SyntaxNode node,
+            IMethodSymbol methodSymbol,
+            KnownTypes knownTypes,
+            CancellationToken cancellationToken)
         {
             var name = methodSymbol.Name;
             var newName = name + AsyncSuffix;
@@ -134,18 +172,20 @@ private SyntaxNode GetContainingFunction(Diagnostic diagnostic, CancellationToke
             {
                 var semanticModel = await newDocument.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
                 var newMethod = (IMethodSymbol)semanticModel.GetDeclaredSymbol(newNode, cancellationToken);
-                return await AddAsyncTokenAsync(keepVoid, newDocument, newMethod, newNode, cancellationToken).ConfigureAwait(false);
+                return await AddAsyncTokenAsync(keepVoid, newDocument, newMethod, knownTypes, newNode, cancellationToken).ConfigureAwait(false);
             }
 
             return newSolution;
         }
 
         private async Task<Solution> AddAsyncTokenAsync(
-            bool keepVoid, Document document, IMethodSymbol methodSymbolOpt,
-            SyntaxNode node, CancellationToken cancellationToken)
+            bool keepVoid,
+            Document document,
+            IMethodSymbol methodSymbolOpt,
+            KnownTypes knownTypes,
+            SyntaxNode node,
+            CancellationToken cancellationToken)
         {
-            var compilation = await document.Project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
-            var knownTypes = new KnownTypes(compilation);
             var newNode = AddAsyncTokenAndFixReturnType(keepVoid, methodSymbolOpt, node, knownTypes);
 
             var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);

src/Features/VisualBasic/Portable/MakeMethodAsynchronous/VisualBasicMakeMethodAsynchronousCodeFixProvider.vb

@@ -43,6 +43,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.MakeMethodAsynchronous
             Return node.IsAsyncSupportedFunctionSyntax()
         End Function
 
+        Protected Overrides Function IsAsyncReturnType(type As ITypeSymbol, knownTypes As KnownTypes) As Boolean
+            Return IsTaskLike(type, knownTypes)
+        End Function
+
         Protected Overrides Function AddAsyncTokenAndFixReturnType(
                 keepVoid As Boolean, methodSymbolOpt As IMethodSymbol, node As SyntaxNode,
                 knownTypes As KnownTypes) As SyntaxNode