Add MakeStatementAsynchronous fixer

src/EditorFeatures/CSharpTest/Diagnostics/MakeStatementAsynchronous/CSharpMakeStatementAsynchronousCodeFixTests.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  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.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.CodeFixes.MakeStatementAsynchronous;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics.MakeStatementAsynchronous
+{
+    [Trait(Traits.Feature, Traits.Features.CodeActionsMakeStatementAsynchronous)]
+    public class CSharpMakeStatementAsynchronousCodeFixTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest
+    {
+        internal override (DiagnosticAnalyzer, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)
+            => (null, new CSharpMakeStatementAsynchronousCodeFixProvider());
+
+        private static readonly TestParameters s_asyncStreamsFeature = new TestParameters(parseOptions: new CSharpParseOptions(LanguageVersion.CSharp8));
+
+        private readonly string AsyncStreams = @"
+namespace System.Collections.Generic
+{
+    public interface IAsyncEnumerable<out T>
+    {
+        IAsyncEnumerator<T> GetAsyncEnumerator();
+    }
+
+    public interface IAsyncEnumerator<out T> : System.IAsyncDisposable
+    {
+        System.Threading.Tasks.ValueTask<bool> MoveNextAsync();
+        T Current { get; }
+    }
+}
+namespace System
+{
+    public interface IAsyncDisposable
+    {
+        System.Threading.Tasks.ValueTask DisposeAsync();
+    }
+}
+";
+
+        [Fact]
+        public async Task FixAll()
+        {
+            await TestInRegularAndScript1Async(
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<int> collection)
+    {
+        foreach (var i in {|FixAllInDocument:collection|}) { }
+        foreach (var j in collection) { }
+    }
+}",
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<int> collection)
+    {
+        await foreach (var i in collection) { }
+
+        await foreach (var j in collection) { }
+    }
+}", parameters: s_asyncStreamsFeature);
+        }
+
+        [Fact]
+        public async Task FixForeach()
+        {
+            await TestInRegularAndScript1Async(
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<int> collection)
+    {
+        foreach (var i in [|collection|])
+        {
+        }
+    }
+}",
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<int> collection)
+    {
+        await foreach (var i in collection)
+        {
+        }
+    }
+}", parameters: s_asyncStreamsFeature);
+        }
+
+        [Fact]
+        public async Task FixForeachDeconstruction()
+        {
+            await TestInRegularAndScript1Async(
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<(int, int)> collection)
+    {
+        foreach (var (i, j) in collection[||])
+        {
+        }
+    }
+}",
+AsyncStreams + @"
+class Program
+{
+    void M(System.Collections.Generic.IAsyncEnumerable<(int, int)> collection)
+    {
+        await foreach (var (i, j) in collection)
+        {
+        }
+    }
+}", parameters: s_asyncStreamsFeature);
+        }
+
+        [Fact]
+        public async Task FixUsingStatement()
+        {
+            await TestInRegularAndScript1Async(
+AsyncStreams + @"
+class Program
+{
+    void M(System.IAsyncDisposable disposable)
+    {
+        using (var i = disposable[||])
+        {
+        }
+    }
+}",
+AsyncStreams + @"
+class Program
+{
+    void M(System.IAsyncDisposable disposable)
+    {
+        await using (var i = disposable)
+        {
+        }
+    }
+}", parameters: s_asyncStreamsFeature);
+        }
+
+        [Fact]
+        public async Task FixUsingDeclaration()
+        {
+            await TestInRegularAndScript1Async(
+AsyncStreams + @"
+class Program
+{
+    void M(System.IAsyncDisposable disposable)
+    {
+        using var i = disposable[||];
+    }
+}",
+AsyncStreams + @"
+class Program
+{
+    void M(System.IAsyncDisposable disposable)
+    {
+        await using var i = disposable;
+    }
+}", parameters: s_asyncStreamsFeature);
+        }
+    }
+}

src/Features/CSharp/Portable/CSharpFeaturesResources.Designer.cs

@@ -1296,6 +1296,15 @@ internal class CSharpFeaturesResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Use asynchronous statement.
+        /// </summary>
+        internal static string Use_asynchronous_statement {
+            get {
+                return ResourceManager.GetString("Use_asynchronous_statement", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use explicit type.
         /// </summary>

src/Features/CSharp/Portable/CSharpFeaturesResources.resx

@@ -168,6 +168,9 @@
   <data name="Declare_as_nullable" xml:space="preserve">
     <value>Declare as nullable</value>
   </data>
+  <data name="Use_asynchronous_statement" xml:space="preserve">
+    <value>Use asynchronous statement</value>
+  </data>
   <data name="Simplify_name_0" xml:space="preserve">
     <value>Simplify name '{0}'</value>
   </data>

src/Features/CSharp/Portable/CodeFixes/MakeStatementAsynchronous/CSharpMakeStatementAsynchronousCodeFixProvider.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Immutable;
+using System.Composition;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp.Extensions;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.CSharp.CodeFixes.MakeStatementAsynchronous
+{
+    [ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.MakeStatementAsynchronous), Shared]
+    internal class CSharpMakeStatementAsynchronousCodeFixProvider : SyntaxEditorBasedCodeFixProvider
+    {
+        // error CS8414: foreach statement cannot operate on variables of type 'IAsyncEnumerable<int>' because 'IAsyncEnumerable<int>' does not contain a public instance definition for 'GetEnumerator'. Did you mean 'await foreach'?
+        // error CS8418: 'IAsyncDisposable': type used in a using statement must be implicitly convertible to 'System.IDisposable'. Did you mean 'await using' rather than 'using'?
+        public sealed override ImmutableArray<string> FixableDiagnosticIds => ImmutableArray.Create("CS8414", "CS8418");
+
+        public override async Task RegisterCodeFixesAsync(CodeFixContext context)
+        {
+            var diagnostic = context.Diagnostics.First();
+            var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
+            var node = root.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true);
+
+            var constructToFix = TryGetStatementToFix(node);
+            if (constructToFix == null)
+            {
+                return;
+            }
+
+            context.RegisterCodeFix(new MyCodeAction(
+                c => FixAsync(context.Document, diagnostic, c)),
+                context.Diagnostics);
+        }
+
+        protected override Task FixAllAsync(
+            Document document, ImmutableArray<Diagnostic> diagnostics,
+            SyntaxEditor editor, CancellationToken cancellationToken)
+        {
+            var root = editor.OriginalRoot;
+
+            foreach (var diagnostic in diagnostics)
+            {
+                var node = diagnostic.Location.FindNode(getInnermostNodeForTie: true, cancellationToken);
+                var statementToFix = TryGetStatementToFix(node);
+                if (statementToFix != null)
+                {
+                    MakeStatementAsynchronous(document, editor, statementToFix);
+                }
+            }
+
+            return Task.CompletedTask;
+        }
+
+        private static void MakeStatementAsynchronous(Document document, SyntaxEditor editor, SyntaxNode statementToFix)
+        {
+            SyntaxNode newStatement;
+            switch (statementToFix)
+            {
+                case ForEachStatementSyntax forEach:
+                    newStatement = forEach.WithAwaitKeyword(SyntaxFactory.Token(SyntaxKind.AwaitKeyword));
+                    break;
+                case ForEachVariableStatementSyntax forEachDeconstruction:
+                    newStatement = forEachDeconstruction.WithAwaitKeyword(SyntaxFactory.Token(SyntaxKind.AwaitKeyword));
+                    break;
+                case UsingStatementSyntax usingStatement:
+                    newStatement = usingStatement.WithAwaitKeyword(SyntaxFactory.Token(SyntaxKind.AwaitKeyword));
+                    break;
+                case LocalDeclarationStatementSyntax localDeclaration:
+                    newStatement = localDeclaration.WithAwaitKeyword(SyntaxFactory.Token(SyntaxKind.AwaitKeyword));
+                    break;
+                default:
+                    return;
+            }
+
+            editor.ReplaceNode(statementToFix, newStatement);
+        }
+
+        private static SyntaxNode TryGetStatementToFix(SyntaxNode node)
+        {
+            if (node.IsParentKind(SyntaxKind.ForEachStatement, SyntaxKind.ForEachVariableStatement, SyntaxKind.UsingStatement))
+            {
+                return node.Parent;
+            }
+
+            if (node is LocalDeclarationStatementSyntax localDeclaration && localDeclaration.UsingKeyword != default)
+            {
+                return node;
+            }
+
+            return null;
+        }
+
+        private class MyCodeAction : CodeAction.DocumentChangeAction
+        {
+            public MyCodeAction(Func<CancellationToken, Task<Document>> createChangedDocument) :
+                base(CSharpFeaturesResources.Use_asynchronous_statement,
+                     createChangedDocument,
+                     CSharpFeaturesResources.Use_asynchronous_statement)
+            {
+            }
+        }
+    }
+}

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.cs.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Seřadit modifikátory dostupnosti</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">Příkaz if lze zjednodušit.</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.de.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Zugriffsmodifizierer sortieren</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">Die If-Anweisung kann vereinfacht werden.</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.es.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Ordenar modificadores de accesibilidad</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">La instrucción "if" se puede simplificar</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.fr.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Trier les modificateurs d'accessibilité</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">L'instruction 'if' peut être simplifiée</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.it.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Ordina i modificatori di accessibilità</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">L'istruzione 'If' può essere semplificata</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.ja.xlf

@@ -122,6 +122,11 @@
         <target state="translated">アクセシビリティ修飾子を並べ替える</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">'if' ステートメントは簡素化できます</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.ko.xlf

@@ -122,6 +122,11 @@
         <target state="translated">접근성 한정자 정렬</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">'if' 문을 간단하게 줄일 수 있습니다.</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.pl.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Sortuj modyfikatory dostępności</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">Instrukcja „if” może zostać uproszczona</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.pt-BR.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Classificar modificadores de acessibilidade</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">A instrução 'if' pode ser simplificada</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.ru.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Сортировать модификаторы доступности</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">Оператор if можно упростить</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.tr.xlf

@@ -122,6 +122,11 @@
         <target state="translated">Erişilebilirlik değiştiricilerini sırala</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">'If' deyimi basitleştirilebilir</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.zh-Hans.xlf

@@ -122,6 +122,11 @@
         <target state="translated">对可访问性修饰符排序</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">可简化“If”语句</target>

src/Features/CSharp/Portable/xlf/CSharpFeaturesResources.zh-Hant.xlf

@@ -122,6 +122,11 @@
         <target state="translated">排序協助工具修飾詞</target>
         <note />
       </trans-unit>
+      <trans-unit id="Use_asynchronous_statement">
+        <source>Use asynchronous statement</source>
+        <target state="new">Use asynchronous statement</target>
+        <note />
+      </trans-unit>
       <trans-unit id="if_statement_can_be_simplified">
         <source>'if' statement can be simplified</source>
         <target state="translated">'if' 陳述式可簡化</target>

src/Features/Core/Portable/CodeFixes/PredefinedCodeFixProviderNames.cs

@@ -37,6 +37,7 @@ internal static class PredefinedCodeFixProviderNames
         public const string ImplementInterface = nameof(ImplementInterface);
         public const string InsertMissingCast = nameof(InsertMissingCast);
         public const string MakeFieldReadonly = nameof(MakeFieldReadonly);
+        public const string MakeStatementAsynchronous = nameof(MakeStatementAsynchronous);
         public const string MakeMethodSynchronous = nameof(MakeMethodSynchronous);
         public const string MoveToTopOfFile = nameof(MoveToTopOfFile);
         public const string PopulateSwitch = nameof(PopulateSwitch);

src/Test/Utilities/Portable/Traits/Traits.cs

@@ -101,6 +101,7 @@ public static class Features
             public const string CodeActionsInvokeDelegateWithConditionalAccess = "CodeActions.InvokeDelegateWithConditionalAccess";
             public const string CodeActionsLambdaSimplifier = "CodeActions.LambdaSimplifier";
             public const string CodeActionsMakeFieldReadonly = "CodeActions.MakeFieldReadonly";
+            public const string CodeActionsMakeStatementAsynchronous = "CodeActions.MakeStatementAsynchronous";
             public const string CodeActionsMakeLocalFunctionStatic = "CodeActions.MakeLocalFunctionStatic";
             public const string CodeActionsMakeMethodAsynchronous = "CodeActions.MakeMethodAsynchronous";
             public const string CodeActionsMakeMethodSynchronous = "CodeActions.MakeMethodSynchronous";