Add feature flag to allow VS to use the LSP based editor

src/EditorFeatures/Core.Wpf/InlineRename/CommandHandlers/RenameCommandHandler_RenameHandler.cs

@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
 using Microsoft.CodeAnalysis.Notification;
 using Roslyn.Utilities;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.Implementation.InlineRename
 {
@@ -108,7 +109,8 @@ private static bool CanRename(RenameCommandArgs args)
         {
             return args.SubjectBuffer.TryGetWorkspace(out var workspace) &&
                 workspace.CanApplyChange(ApplyChangesKind.ChangeDocument) &&
-                args.SubjectBuffer.SupportsRename();
+                args.SubjectBuffer.SupportsRename() &&
+                !workspace.Services.GetService<IWorkspaceContextService>().IsInLspEditorContext();
         }
 
         private static void ShowErrorDialog(Workspace workspace, string message)

src/EditorFeatures/Core.Wpf/Suggestions/SuggestedActionsSource.cs

@@ -178,6 +178,11 @@ public bool TryGetTelemetryId(out Guid telemetryId)
                     return null;
                 }
 
+                if (range.Snapshot.TextBuffer.IsInLspEditorContext())
+                {
+                    return null;
+                }
+
                 if (_workspaceStatusService != null)
                 {
                     using (operationContext?.AddScope(allowCancellation: true, description: EditorFeaturesWpfResources.Gathering_Suggestions_Waiting_for_the_solution_to_fully_load))

src/EditorFeatures/Core/Implementation/Classification/SemanticClassificationUtilities.cs

@@ -34,6 +34,11 @@ public static async Task ProduceTagsAsync(
             IClassificationService classificationService,
             ClassificationTypeMap typeMap)
         {
+            if (spanToTag.SnapshotSpan.Snapshot.TextBuffer.IsInLspEditorContext())
+            {
+                return;
+            }
+
             var document = spanToTag.Document;
             if (document == null)
             {

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

@@ -6,6 +6,7 @@
 using System.ComponentModel.Composition;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Editor;
+using Microsoft.CodeAnalysis.Experiments;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer;
 using Microsoft.CodeAnalysis.Options;
@@ -27,6 +28,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation.LanguageClient
     [Export(typeof(AlwaysActivateInProcLanguageClient))]
     internal class AlwaysActivateInProcLanguageClient : AbstractInProcLanguageClient
     {
+        private readonly DefaultCapabilitiesProvider _defaultCapabilitiesProvider;
         private readonly IGlobalOptionService _globalOptionService;
 
         [ImportingConstructor]
@@ -36,27 +38,37 @@ public AlwaysActivateInProcLanguageClient(
             LanguageServerProtocol languageServerProtocol,
             VisualStudioWorkspace workspace,
             IAsynchronousOperationListenerProvider listenerProvider,
-            ILspSolutionProvider solutionProvider)
+            ILspSolutionProvider solutionProvider,
+            DefaultCapabilitiesProvider defaultCapabilitiesProvider)
             : base(languageServerProtocol, workspace, diagnosticService: null, listenerProvider, solutionProvider, diagnosticsClientName: null)
         {
             _globalOptionService = globalOptionService;
+            _defaultCapabilitiesProvider = defaultCapabilitiesProvider;
         }
 
         public override string Name
             => ServicesVSResources.CSharp_Visual_Basic_Language_Server_Client;
 
         protected internal override VSServerCapabilities GetCapabilities()
-            => new VSServerCapabilities
+        {
+            var serverCapabilities = new VSServerCapabilities();
+
+            // If the LSP editor feature flag is enabled advertise support for LSP features here so they are available locally and remote.
+            if (Workspace.Services.GetRequiredService<IExperimentationService>().IsExperimentEnabled(VisualStudioWorkspaceContextService.LspEditorFeatureFlagName))
+            {
+                serverCapabilities = _defaultCapabilitiesProvider.GetCapabilities();
+            }
+
+            serverCapabilities.TextDocumentSync = new TextDocumentSyncOptions
             {
-                TextDocumentSync = new TextDocumentSyncOptions
-                {
-                    Change = TextDocumentSyncKind.Incremental,
-                    OpenClose = true,
-                },
-                SupportsDiagnosticRequests = this.Workspace.IsPullDiagnostics(InternalDiagnosticsOptions.NormalDiagnosticMode),
-                // This flag ensures that ctrl+, search locally uses the old editor APIs so that only ctrl+Q search is powered via LSP.
-                DisableGoToWorkspaceSymbols = true,
-                WorkspaceSymbolProvider = true,
+                Change = TextDocumentSyncKind.Incremental,
+                OpenClose = true,
             };
+            serverCapabilities.SupportsDiagnosticRequests = this.Workspace.IsPullDiagnostics(InternalDiagnosticsOptions.NormalDiagnosticMode);
+            serverCapabilities.DisableGoToWorkspaceSymbols = true;
+            serverCapabilities.WorkspaceSymbolProvider = true;
+
+            return serverCapabilities;
+        }
     }
 }

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

@@ -6,6 +6,7 @@
 using System.ComponentModel.Composition;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Editor;
+using Microsoft.CodeAnalysis.Experiments;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer;
 using Microsoft.CodeAnalysis.Shared.TestHooks;
@@ -42,6 +43,17 @@ public LiveShareInProcLanguageClient(
         public override string Name => ServicesVSResources.Live_Share_CSharp_Visual_Basic_Language_Server_Client;
 
         protected internal override VSServerCapabilities GetCapabilities()
-            => _defaultCapabilitiesProvider.GetCapabilities();
+        {
+            var experimentationService = Workspace.Services.GetRequiredService<IExperimentationService>();
+            var isLspEditorEnabled = experimentationService.IsExperimentEnabled(VisualStudioWorkspaceContextService.LspEditorFeatureFlagName);
+            // If the preview feature flag to turn on the LSP editor in local scenarios is on, advertise no capabilities for this Live Share
+            // LSP server as LSP requests will be serviced by the AlwaysActiveInProcLanguageClient in both local and remote scenarios.
+            if (isLspEditorEnabled)
+            {
+                return new VSServerCapabilities();
+            }
+
+            return _defaultCapabilitiesProvider.GetCapabilities();
+        }
     }
 }

src/VisualStudio/Core/Def/Implementation/VisualStudioWorkspaceContextService.cs

@@ -4,7 +4,9 @@
 
 using System;
 using System.Composition;
+using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
+using Microsoft.CodeAnalysis.Experiments;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.VisualStudio.Shell;
 
@@ -13,14 +15,23 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation
     [ExportWorkspaceService(typeof(IWorkspaceContextService), ServiceLayer.Host), Shared]
     internal class VisualStudioWorkspaceContextService : IWorkspaceContextService
     {
+        /// <summary>
+        /// Roslyn LSP feature flag name, as defined in the PackageRegistraion.pkgdef
+        /// by everything following '$RootKey$\FeatureFlags\' and '\' replaced by '.'
+        /// </summary>
+        public const string LspEditorFeatureFlagName = "Roslyn.LSP.Editor";
+
         // UI context defined by Live Share when connected as a guest in a Live Share session
         // https://devdiv.visualstudio.com/DevDiv/_git/Cascade?path=%2Fsrc%2FVS%2FContracts%2FGuidList.cs&version=GBmaster&line=32&lineEnd=33&lineStartColumn=1&lineEndColumn=1&lineStyle=plain&_a=contents
         private static readonly Guid LiveShareGuestUIContextGuid = Guid.Parse("fd93f3eb-60da-49cd-af15-acda729e357e");
 
+        private readonly Workspace _workspace;
+
         [ImportingConstructor]
         [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
-        public VisualStudioWorkspaceContextService()
+        public VisualStudioWorkspaceContextService(VisualStudioWorkspace vsWorkspace)
         {
+            _workspace = vsWorkspace;
         }
 
         public bool IsCloudEnvironmentClient()
@@ -31,7 +42,9 @@ public bool IsCloudEnvironmentClient()
 
         public bool IsInLspEditorContext()
         {
-            return IsLiveShareGuest() || IsCloudEnvironmentClient();
+            var featureFlagService = _workspace.Services.GetRequiredService<IExperimentationService>();
+            var isInLspContext = IsLiveShareGuest() || IsCloudEnvironmentClient() || featureFlagService.IsExperimentEnabled(LspEditorFeatureFlagName);
+            return isInLspContext;
         }
 
         /// <summary>

src/VisualStudio/Core/Def/PackageRegistration.pkgdef

@@ -13,3 +13,8 @@
 "CS"="CA719A03-D55C-48F9-85DE-D934346E7F70"
 "VB"="EEC3DF0D-6D3F-4544-ABF9-8E26E6A90275"
 
+[$RootKey$\FeatureFlags\Roslyn\LSP\Editor]
+"Description"="Enables the LSP powered C#/VB editing experience outside of CodeSpaces."
+"Value"=dword:00000000
+"Title"="Enable experimental C#/VB editor (requires restart)"
+"PreviewPaneChannels"="Preview,int.main"