Add tests and resource files

src/Analyzers/Core/CodeFixes/CodeFixesResources.resx

@@ -144,4 +144,7 @@
   <data name="Update_suppression_format" xml:space="preserve">
     <value>Update suppression format</value>
   </data>
+  <data name="Suppress_or_Configure_issues" xml:space="preserve">
+    <value>Suppress or Configure issues</value>
+  </data>
 </root>
\ No newline at end of file

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.cs.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.de.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.es.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.fr.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.it.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.ja.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.ko.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.pl.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.pt-BR.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.ru.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.tr.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.zh-Hans.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/Analyzers/Core/CodeFixes/xlf/CodeFixesResources.zh-Hant.xlf

@@ -32,6 +32,11 @@
         <target state="new">Remove redundant suppression</target>
         <note />
       </trans-unit>
+      <trans-unit id="Suppress_or_Configure_issues">
+        <source>Suppress or Configure issues</source>
+        <target state="new">Suppress or Configure issues</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Update_suppression_format">
         <source>Update suppression format</source>
         <target state="new">Update suppression format</target>

src/EditorFeatures/TestUtilities/LanguageServer/AbstractLanguageServerProtocolTests.cs

@@ -216,7 +216,7 @@ private protected static RunCodeActionParams CreateRunCodeActionParams(string co
                     Range = location.Range,
                     Context = new LSP.CodeActionContext()
                 },
-                Title = codeActionTitle
+                DistinctTitle = codeActionTitle
             };
 
         /// <summary>

src/Features/LanguageServer/Protocol/CustomProtocol/RunCodeActionParams.cs

@@ -21,6 +21,6 @@ internal class RunCodeActionParams
         /// <summary>
         /// Title of the action to execute.
         /// </summary>
-        public string Title { get; set; }
+        public string DistinctTitle { get; set; }
     }
 }

src/Features/LanguageServer/Protocol/Handler/CodeActions/CodeActionResolveHandler.cs

@@ -25,7 +25,7 @@
 namespace Microsoft.CodeAnalysis.LanguageServer.Handler
 {
     /// <summary>
-    /// Handles the get code actions command.
+    /// Resolves a code action by filling out its Edit or Command property.
     /// </summary>
     [ExportLspMethod(MSLSPMethods.TextDocumentCodeActionResolveName), Shared]
     internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeAction, LSP.VSCodeAction>
@@ -74,7 +74,7 @@ internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeActio
                 return codeAction;
             }
 
-            var codeActionToResolve = GetCodeActionToResolve(data, codeActions);
+            var codeActionToResolve = GetCodeActionToResolve(data.DistinctTitle, codeActions);
 
             // We didn't find a matching action, so just return the action without an edit or command.
             if (codeActionToResolve == null)
@@ -88,33 +88,79 @@ internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeActio
                 return codeAction;
             }
 
-            // TO-DO: We currently must execute code actions which add new documents on the server as commands,
-            // since there is  no LSP support for adding documents yet. In the future, we should move these actions
-            // to primarily executing on the client.
+            // TO-DO:
+            // 1) We currently must execute code actions which add new documents on the server as commands,
+            // since there is no LSP support for adding documents yet. In the future, we should move these actions
+            // to execute on the client.
+            // 2) There is also a bug (same tracking item) where code actions that edit documents other than the
+            // one where the code action was invoked from do not work. We must temporarily execute these as commands
+            // as well.
             // https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1147293/
             var runAsCommand = false;
 
             var applyChangesOperations = operations.Where(operation => operation is ApplyChangesOperation);
             if (applyChangesOperations.Any())
+            {
+                var workspaceEdits = await ComputeWorkspaceEdits(applyChangesOperations, document!, cancellationToken).ConfigureAwait(false);
+                if (workspaceEdits.Any())
+                {
+                    codeAction.Edit = new LSP.WorkspaceEdit { DocumentChanges = workspaceEdits };
+                }
+                else
+                {
+                    // The workspace edit is something we don't currently support, like adding a new document.
+                    runAsCommand = true;
+                }
+            }
+
+            // Set up to run as command on the server instead of using WorkspaceEdits.
+            var commandOperations = operations.All(operation => !(operation is ApplyChangesOperation));
+            if (commandOperations || runAsCommand)
+            {
+                codeAction.Command = SetCommand(codeAction, data);
+            }
+
+            return codeAction;
+
+            // Local functions
+            static async Task<TextDocumentEdit[]> ComputeWorkspaceEdits(
+                IEnumerable<CodeActionOperation> applyChangesOperations,
+                Document document,
+                CancellationToken cancellationToken)
             {
                 using var _ = ArrayBuilder<TextDocumentEdit>.GetInstance(out var textDocumentEdits);
                 foreach (ApplyChangesOperation applyChangesOperation in applyChangesOperations)
                 {
-                    var solution = document!.Project.Solution;
+                    var solution = document.Project.Solution;
                     var changes = applyChangesOperation.ChangedSolution.GetChanges(solution);
                     var projectChanges = changes.GetProjectChanges();
 
-                    // If the change involves adding a document, execute via command instead of WorkspaceEdit.
+                    // TO-DO: If the change involves adding a document, execute via command instead of WorkspaceEdit
+                    // until adding documents is supported in LSP: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1147293/
+                    // After support is added, remove the below if-statement and add code to support adding documents.
                     var addedDocuments = projectChanges.SelectMany(
                         pc => pc.GetAddedDocuments().Concat(pc.GetAddedAdditionalDocuments().Concat(pc.GetAddedAnalyzerConfigDocuments())));
                     if (addedDocuments.Any())
                     {
-                        runAsCommand = true;
-                        break;
+                        return textDocumentEdits.ToArray();
                     }
 
-                    // Changed documents
                     var changedDocuments = projectChanges.SelectMany(pc => pc.GetChangedDocuments());
+                    var changedAnalyzerConfigDocuments = projectChanges.SelectMany(pc => pc.GetChangedAnalyzerConfigDocuments());
+                    var changedAdditionalDocuments = projectChanges.SelectMany(pc => pc.GetChangedAdditionalDocuments());
+
+                    // TO-DO: If the change involves modifying any document besides the document where the code action
+                    // was invoked, temporarily execute via command instead of WorkspaceEdit until LSP bug is fixed:
+                    // https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1147293/
+                    // After bug is fixed, remove the below if-statement and the existing code should work.
+                    if (changedDocuments.Any(d => d != document.Id) ||
+                        changedAnalyzerConfigDocuments.Any() ||
+                        changedAdditionalDocuments.Any())
+                    {
+                        return textDocumentEdits.ToArray();
+                    }
+
+                    // Changed documents
                     foreach (var docId in changedDocuments)
                     {
                         var newDoc = applyChangesOperation.ChangedSolution.GetDocument(docId);
@@ -128,7 +174,8 @@ internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeActio
                     }
 
                     // Changed analyzer config documents
-                    var changedAnalyzerConfigDocuments = projectChanges.SelectMany(pc => pc.GetChangedAnalyzerConfigDocuments());
+                    // This for loop won't currently execute until https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1147293/
+                    // is fixed.
                     foreach (var docId in changedAnalyzerConfigDocuments)
                     {
                         var newDoc = applyChangesOperation.ChangedSolution.GetAnalyzerConfigDocument(docId);
@@ -140,36 +187,26 @@ internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeActio
 
                         await GetTextDocumentEdits(textDocumentEdits, newDoc, oldDoc, cancellationToken).ConfigureAwait(false);
                     }
-                }
 
-                if (!runAsCommand)
-                {
-                    codeAction.Edit = new LSP.WorkspaceEdit { DocumentChanges = textDocumentEdits.ToArray() };
-                }
-            }
-
-            // Running as command instead
-            var commandOperations = operations.Where(operation => !(operation is ApplyChangesOperation));
-            if (commandOperations.Any() || runAsCommand)
-            {
-                codeAction.Command = new LSP.Command
-                {
-                    CommandIdentifier = CodeActionsHandler.RunCodeActionCommandName,
-                    Title = codeAction.Title,
-                    Arguments = new object[]
+                    // Changed additional documents
+                    // This for loop won't currently execute until https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1147293/
+                    // is fixed.
+                    foreach (var docId in changedAdditionalDocuments)
                     {
-                        new RunCodeActionParams
+                        var newDoc = applyChangesOperation.ChangedSolution.GetAdditionalDocument(docId);
+                        var oldDoc = solution.GetAdditionalDocument(docId);
+                        if (oldDoc == null || newDoc == null)
                         {
-                            CodeActionParams = data.CodeActionParams,
-                            Title = codeAction.Title
+                            continue;
                         }
+
+                        await GetTextDocumentEdits(textDocumentEdits, newDoc, oldDoc, cancellationToken).ConfigureAwait(false);
                     }
-                };
-            }
+                }
 
-            return codeAction;
+                return textDocumentEdits.ToArray();
+            }
 
-            // Local functions
             static async Task GetTextDocumentEdits(
                 ArrayBuilder<TextDocumentEdit> textDocumentEdits,
                 TextDocument newDoc,
@@ -186,43 +223,57 @@ internal class CodeActionResolveHandler : AbstractRequestHandler<LSP.VSCodeActio
                 textDocumentEdits.Add(new TextDocumentEdit() { TextDocument = documentIdentifier, Edits = edits.ToArray() });
             }
 
-            static CodeAction? GetCodeActionToResolve(CodeActionResolveData data, IEnumerable<CodeAction> codeActions)
+            static LSP.Command SetCommand(VSCodeAction codeAction, CodeActionResolveData data) => new LSP.Command
             {
-                // First, we search for the matching code action. We compare against the distinct title
-                // instead of the regular title since there's a chance that multiple code actions may have
-                // the same name, e.g. configure code actions ("None", "Warning", etc.).
-                CodeAction? codeActionToResolve = null;
-                foreach (var c in codeActions)
+                CommandIdentifier = CodeActionsHandler.RunCodeActionCommandName,
+                Title = codeAction.Title,
+                Arguments = new object[]
                 {
-                    var action = CheckForMatchingAction(c, data.DistinctTitle, currentTitle: "");
-                    if (action != null)
+                    new RunCodeActionParams
                     {
-                        codeActionToResolve = action;
-                        break;
+                        CodeActionParams = data.CodeActionParams,
+                        DistinctTitle = data.DistinctTitle
                     }
                 }
+            };
+        }
 
-                return codeActionToResolve;
-            }
-
-            static CodeAction? CheckForMatchingAction(CodeAction codeAction, string goalTitle, string currentTitle)
+        internal static CodeAction? GetCodeActionToResolve(string distinctTitle, IEnumerable<CodeAction> codeActions)
+        {
+            // Searching for the matching code action. We compare against the distinct title (e.g. "Suppress IDExxxxNone")
+            // instead of the regular title (e.g. "None") since there's a chance that multiple code actions may have
+            // the same regular title.
+            CodeAction? codeActionToResolve = null;
+            foreach (var c in codeActions)
             {
-                if (currentTitle + codeAction.Title == goalTitle)
+                var action = CheckForMatchingAction(c, distinctTitle, currentTitle: "");
+                if (action != null)
                 {
-                    return codeAction;
+                    codeActionToResolve = action;
+                    break;
                 }
+            }
+
+            return codeActionToResolve;
+        }
 
-                foreach (var nestedAction in codeAction.NestedCodeActions)
+        private static CodeAction? CheckForMatchingAction(CodeAction codeAction, string goalTitle, string currentTitle)
+        {
+            if (currentTitle + codeAction.Title == goalTitle)
+            {
+                return codeAction;
+            }
+
+            foreach (var nestedAction in codeAction.NestedCodeActions)
+            {
+                var match = CheckForMatchingAction(nestedAction, goalTitle, currentTitle + codeAction.Title);
+                if (match != null)
                 {
-                    var match = CheckForMatchingAction(nestedAction, goalTitle, currentTitle + codeAction.Title);
-                    if (match != null)
-                    {
-                        return match;
-                    }
+                    return match;
                 }
-
-                return null;
             }
+
+            return null;
         }
     }
 }

src/Features/LanguageServer/Protocol/Handler/CodeActions/CodeActionsHandler.cs

@@ -17,6 +17,7 @@
 using Microsoft.CodeAnalysis.Editor;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler.CodeActions;
+using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using static Microsoft.CodeAnalysis.CodeActions.CodeAction;
 using CodeAction = Microsoft.CodeAnalysis.CodeActions.CodeAction;
@@ -63,42 +64,50 @@ internal class CodeActionsHandler : AbstractRequestHandler<LSP.CodeActionParams,
             // Filter out code actions with options since they'll show dialogs and we can't remote the UI and the options.
             codeActions = codeActions.Where(c => !(c.Key is CodeActionWithOptions));
 
-            var suppressionActions = codeActions.Where(
-                a => a.Key is AbstractConfigurationActionWithNestedActions &&
-                (a.Key as AbstractConfigurationActionWithNestedActions)?.IsBulkConfigurationAction == false);
+            return GetVSCodeActions(request, codeActions);
 
-            var results = new List<VSCodeAction>();
-            foreach (var codeAction in codeActions)
+            // Local functions
+            static VSCodeAction[] GetVSCodeActions(
+                CodeActionParams request,
+                IEnumerable<KeyValuePair<CodeAction, CodeActionKind>> codeActions)
             {
-                // Temporarily filter out suppress and configure code actions, as we'll later combine them under a top-level
-                // code action.
-                if (codeAction.Key is AbstractConfigurationActionWithNestedActions)
+                var suppressionActions = codeActions.Where(
+                    a => a.Key is AbstractConfigurationActionWithNestedActions &&
+                    (a.Key as AbstractConfigurationActionWithNestedActions)?.IsBulkConfigurationAction == false);
+
+                using var _ = ArrayBuilder<VSCodeAction>.GetInstance(out var results);
+                foreach (var codeAction in codeActions)
                 {
-                    continue;
+                    // Temporarily filter out suppress and configure code actions, as we'll later combine them under a top-level
+                    // code action.
+                    if (codeAction.Key is AbstractConfigurationActionWithNestedActions)
+                    {
+                        continue;
+                    }
+
+                    results.Add(GenerateVSCodeAction(request, codeAction.Key, codeAction.Value));
                 }
 
-                results.Add(GenerateVSCodeAction(request, codeAction.Key, codeAction.Value));
-            }
+                // Special case (also dealt with specially in local Roslyn): 
+                // If we have configure/suppress code actions, combine them under one top-level code action.
+                var configureSuppressActions = codeActions.Where(a => a.Key is AbstractConfigurationActionWithNestedActions);
+                if (configureSuppressActions.Any())
+                {
+                    results.Add(GenerateVSCodeAction(request, new CodeActionWithNestedActions(
+                        CodeFixesResources.Suppress_or_Configure_issues,
+                        configureSuppressActions.Select(a => a.Key).ToImmutableArray(), true), CodeActionKind.QuickFix));
+                }
 
-            // Special case (also dealt with specially in local Roslyn): 
-            // If we have configure/suppress code actions, combine them under one top-level code action.
-            var configureSuppressActions = codeActions.Where(a => a.Key is AbstractConfigurationActionWithNestedActions);
-            if (configureSuppressActions.Any())
-            {
-                results.Add(GenerateVSCodeAction(request, new CodeActionWithNestedActions(
-                    "Suppress or Configure issues",
-                    configureSuppressActions.Select(a => a.Key).ToImmutableArray(), true), CodeActionKind.QuickFix));
+                return results.ToArray();
             }
 
-            return results.ToArray();
-
             static VSCodeAction GenerateVSCodeAction(
                 CodeActionParams request,
                 CodeAction codeAction,
                 CodeActionKind codeActionKind,
                 string parentTitle = "")
             {
-                var nestedActions = new List<VSCodeAction>();
+                using var _ = ArrayBuilder<VSCodeAction>.GetInstance(out var nestedActions);
                 foreach (var action in codeAction.NestedCodeActions)
                 {
                     nestedActions.Add(GenerateVSCodeAction(request, action, codeActionKind, codeAction.Title));

src/Features/LanguageServer/ProtocolUnitTests/CodeActions/CodeActionResolveTests.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.LanguageServer.Handler.CodeActions;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+using Roslyn.Test.Utilities;
+using Xunit;
+using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
+
+namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.CodeActions
+{
+    public class CodeActionResolveTests : AbstractLanguageServerProtocolTests
+    {
+        [Fact]
+        public async Task TestCodeActionResolveHandlerAsync()
+        {
+            var initialMarkup =
+@"class A
+{
+    void M()
+    {
+        {|caret:|}int i = 1;
+    }
+}";
+            using var workspace = CreateTestWorkspace(initialMarkup, out var locations);
+
+            var unresolvedCodeAction = CodeActionsTests.CreateCodeAction(
+                title: CSharpAnalyzersResources.Use_implicit_type,
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
+                {
+                    CodeActionParams = CodeActionsTests.CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = CSharpAnalyzersResources.Use_implicit_type
+                },
+                diagnostics: null);
+
+            var expectedMarkup =
+@"class A
+{
+    void M()
+    {
+        var i = 1;
+    }
+}";
+            var expected = CodeActionsTests.CreateCodeAction(
+                title: CSharpAnalyzersResources.Use_implicit_type,
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
+                {
+                    CodeActionParams = CodeActionsTests.CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = CSharpAnalyzersResources.Use_implicit_type
+                },
+                diagnostics: null,
+                edit: new LSP.WorkspaceEdit()
+                {
+                    DocumentChanges = new TextDocumentEdit[]
+                    {
+                        new TextDocumentEdit()
+                        {
+                            TextDocument = new VersionedTextDocumentIdentifier()
+                            {
+                                Uri = locations["caret"].Single().Uri
+                            },
+                            Edits = new TextEdit[] {
+                                new TextEdit()
+                                {
+                                    NewText = expectedMarkup,
+                                    Range = new LSP.Range() { Start = new Position(0, 0), End = new Position(6, 1) }
+                                }
+                            }
+                        }
+                    }
+                });
+
+            var result = await RunGetCodeActionResolveAsync(workspace.CurrentSolution, unresolvedCodeAction);
+            AssertJsonEquals(expected, result);
+        }
+
+        [Fact]
+        public async Task TestCodeActionResolveHandlerAsync_NestedAction()
+        {
+            var initialMarkup =
+@"class A
+{
+    void M()
+    {
+        int {|caret:|}i = 1;
+    }
+}";
+            using var workspace = CreateTestWorkspace(initialMarkup, out var locations);
+
+            var unresolvedCodeAction = CodeActionsTests.CreateCodeAction(
+                title: string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
+                {
+                    CodeActionParams = CodeActionsTests.CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = FeaturesResources.Introduce_constant + string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                },
+                diagnostics: null);
+
+            var expectedMarkup =
+@"class A
+{
+    private const int V = 1;
+
+    void M()
+    {
+        int i = V;
+    }
+}";
+
+            var expected = CodeActionsTests.CreateCodeAction(
+                title: string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
+                {
+                    CodeActionParams = CodeActionsTests.CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = FeaturesResources.Introduce_constant + string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                },
+                diagnostics: null,
+                edit: new LSP.WorkspaceEdit()
+                {
+                    DocumentChanges = new TextDocumentEdit[]
+                    {
+                        new TextDocumentEdit()
+                        {
+                            TextDocument = new VersionedTextDocumentIdentifier()
+                            {
+                                Uri = locations["caret"].Single().Uri
+                            },
+                            Edits = new TextEdit[] {
+                                new TextEdit()
+                                {
+                                    NewText = expectedMarkup,
+                                    Range = new LSP.Range() { Start = new Position(0, 0), End = new Position(6, 1) }
+                                }
+                            }
+                        }
+                    }
+                });
+
+            var result = await RunGetCodeActionResolveAsync(workspace.CurrentSolution, unresolvedCodeAction);
+            AssertJsonEquals(expected, result);
+        }
+
+        private static async Task<LSP.VSCodeAction> RunGetCodeActionResolveAsync(
+            Solution solution,
+            VSCodeAction unresolvedCodeAction,
+            LSP.ClientCapabilities clientCapabilities = null)
+        {
+            var result = await GetLanguageServer(solution).ExecuteRequestAsync<LSP.VSCodeAction, LSP.VSCodeAction>(
+                LSP.MSLSPMethods.TextDocumentCodeActionResolveName, unresolvedCodeAction,
+                clientCapabilities, null, CancellationToken.None);
+            return result;
+        }
+    }
+}

src/Features/LanguageServer/ProtocolUnitTests/CodeActions/CodeActionsTests.cs

@@ -2,11 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CSharp;
-using Newtonsoft.Json.Linq;
+using Microsoft.CodeAnalysis.LanguageServer.Handler.CodeActions;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Roslyn.Test.Utilities;
 using Xunit;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
@@ -16,7 +18,7 @@ namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.CodeActions
     public class CodeActionsTests : AbstractLanguageServerProtocolTests
     {
         [Fact]
-        public async Task TestGetCodeActionsAsync()
+        public async Task TestCodeActionHandlerAsync()
         {
             var markup =
 @"class A
@@ -27,31 +29,68 @@ void M()
     }
 }";
             using var workspace = CreateTestWorkspace(markup, out var locations);
-            var expected = CreateCommand(CSharpAnalyzersResources.Use_implicit_type, locations["caret"].Single());
-            var clientCapabilities = CreateClientCapabilitiesWithExperimentalValue("supportsWorkspaceEdits", JToken.FromObject(false));
 
-            var results = await RunGetCodeActionsAsync(workspace.CurrentSolution, locations["caret"].Single(), clientCapabilities);
-            var useImplicitTypeResult = results.Single(r => r.Title == CSharpAnalyzersResources.Use_implicit_type);
-            AssertJsonEquals(expected, useImplicitTypeResult);
+            var expected = CreateCodeAction(
+                title: CSharpAnalyzersResources.Use_implicit_type,
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
+                {
+                    CodeActionParams = CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = CSharpAnalyzersResources.Use_implicit_type
+                },
+                diagnostics: null);
+
+            var results = await RunGetCodeActionsAsync(workspace.CurrentSolution, locations["caret"].Single());
+            var useImplicitType = results.FirstOrDefault(r => r.Title == CSharpAnalyzersResources.Use_implicit_type);
+
+            AssertJsonEquals(expected, useImplicitType);
         }
 
-        private static async Task<LSP.Command[]> RunGetCodeActionsAsync(Solution solution, LSP.Location caret, LSP.ClientCapabilities clientCapabilities = null)
+        [Fact]
+        public async Task TestCodeActionHandlerAsync_NestedAction()
         {
-            var results = await GetLanguageServer(solution).ExecuteRequestAsync<LSP.CodeActionParams, LSP.SumType<LSP.Command, LSP.CodeAction>[]>(LSP.Methods.TextDocumentCodeActionName,
-                CreateCodeActionParams(caret), clientCapabilities, null, CancellationToken.None);
-            return results.Select(r => (LSP.Command)r).ToArray();
-        }
+            var markup =
+@"class A
+{
+    void M()
+    {
+        int {|caret:|}i = 1;
+    }
+}";
+            using var workspace = CreateTestWorkspace(markup, out var locations);
 
-        private static LSP.ClientCapabilities CreateClientCapabilitiesWithExperimentalValue(string experimentalProperty, JToken value)
-            => new LSP.ClientCapabilities()
-            {
-                Experimental = new JObject
+            var expected = CreateCodeAction(
+                title: string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                kind: CodeActionKind.Refactor,
+                children: Array.Empty<LSP.VSCodeAction>(),
+                data: new CodeActionResolveData
                 {
-                    { experimentalProperty, value }
-                }
-            };
+                    CodeActionParams = CreateCodeActionParams(locations["caret"].Single()),
+                    DistinctTitle = FeaturesResources.Introduce_constant + string.Format(FeaturesResources.Introduce_constant_for_0, "1"),
+                },
+                diagnostics: null);
 
-        private static LSP.CodeActionParams CreateCodeActionParams(LSP.Location caret)
+            var results = await RunGetCodeActionsAsync(workspace.CurrentSolution, locations["caret"].Single());
+            var introduceConstant = results[0].Children.FirstOrDefault(
+                r => ((CodeActionResolveData)r.Data).DistinctTitle == FeaturesResources.Introduce_constant
+                + string.Format(FeaturesResources.Introduce_constant_for_0, "1"));
+
+            AssertJsonEquals(expected, introduceConstant);
+        }
+
+        private static async Task<LSP.VSCodeAction[]> RunGetCodeActionsAsync(
+            Solution solution,
+            LSP.Location caret,
+            LSP.ClientCapabilities clientCapabilities = null)
+        {
+            var result = await GetLanguageServer(solution).ExecuteRequestAsync<LSP.CodeActionParams, LSP.VSCodeAction[]>(
+                LSP.Methods.TextDocumentCodeActionName, CreateCodeActionParams(caret),
+                clientCapabilities, null, CancellationToken.None);
+            return result;
+        }
+
+        internal static LSP.CodeActionParams CreateCodeActionParams(LSP.Location caret)
             => new LSP.CodeActionParams()
             {
                 TextDocument = CreateTextDocumentIdentifier(caret.Uri),
@@ -62,15 +101,31 @@ private static LSP.CodeActionParams CreateCodeActionParams(LSP.Location caret)
                 }
             };
 
-        private static LSP.Command CreateCommand(string title, LSP.Location location)
-            => new LSP.Command()
+        internal static LSP.VSCodeAction CreateCodeAction(
+            string title, LSP.CodeActionKind kind, LSP.VSCodeAction[] children,
+            CodeActionResolveData data, LSP.Diagnostic[] diagnostics,
+            LSP.WorkspaceEdit edit = null, LSP.Command command = null)
+        {
+            var action = new LSP.VSCodeAction
             {
                 Title = title,
-                CommandIdentifier = "Roslyn.RunCodeAction",
-                Arguments = new object[]
-                {
-                    CreateRunCodeActionParams(title, location)
-                }
+                Kind = kind,
+                Children = children,
+                Data = data,
+                Diagnostics = diagnostics,
             };
+
+            if (edit != null)
+            {
+                action.Edit = edit;
+            }
+
+            if (command != null)
+            {
+                action.Command = command;
+            }
+
+            return action;
+        }
     }
 }

src/VisualStudio/Core/Def/Implementation/LanguageClient/VisualStudioLspSolutionProvider.cs

@@ -7,11 +7,9 @@
 using System;
 using System.Collections.Immutable;
 using System.Composition;
-using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer;
-using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.LanguageClient

src/VisualStudio/LiveShare/Impl/PreviewCodeActionsHandler.cs

@@ -41,7 +41,7 @@ public async Task<LSP.TextEdit[]> HandleAsync(RunCodeActionParams request, Reque
                 request.CodeActionParams.Range,
                 cancellationToken).ConfigureAwait(false);
 
-            var actionToRun = codeActions?.FirstOrDefault(a => a.Title == request.Title);
+            var actionToRun = codeActions?.FirstOrDefault(a => a.Title == request.DistinctTitle);
 
             if (actionToRun != null)
             {

src/VisualStudio/LiveShare/Impl/RunCodeActionsHandler.cs

@@ -7,7 +7,6 @@
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CodeFixes;
 using Microsoft.CodeAnalysis.CodeRefactorings;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
@@ -22,8 +21,8 @@
 namespace Microsoft.VisualStudio.LanguageServices.LiveShare
 {
     /// <summary>
-    /// Run code actions handler.  Called when lightbulb invoked.
-    /// Code actions must be applied from the UI thread in VS.
+    /// Runs code actions as a command on the server.
+    /// Commands must be applied from the UI thread in VS.
     /// </summary>
     [ExportExecuteWorkspaceCommand(CodeActionsHandler.RunCodeActionCommandName)]
     internal class RunCodeActionsHandler : IExecuteWorkspaceCommandHandler
@@ -56,12 +55,14 @@ internal class RunCodeActionsHandler : IExecuteWorkspaceCommandHandler
             var document = _solutionProvider.GetDocument(runRequest.CodeActionParams.TextDocument);
             var codeActions = await CodeActionsHandler.GetCodeActionsAsync(document, _codeFixService, _codeRefactoringService,
                 runRequest.CodeActionParams.Range, cancellationToken).ConfigureAwait(false);
+            if (codeActions == null)
+            {
+                return false;
+            }
 
-            var actionToRun = codeActions?.FirstOrDefault(a => a.Title == runRequest.Title);
-
+            var actionToRun = CodeActionResolveHandler.GetCodeActionToResolve(runRequest.DistinctTitle, codeActions);
             if (actionToRun != null)
             {
-                // add check here
                 foreach (var operation in await actionToRun.GetOperationsAsync(cancellationToken).ConfigureAwait(false))
                 {
                     // TODO - This UI thread dependency should be removed.
@@ -69,9 +70,11 @@ internal class RunCodeActionsHandler : IExecuteWorkspaceCommandHandler
                     await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
                     operation.Apply(document.Project.Solution.Workspace, cancellationToken);
                 }
+
+                return true;
             }
 
-            return true;
+            return false;
         }
     }
 }