Make IStreamingFindUsagesPresenters a required export

src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionService.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.Composition;
 using Microsoft.CodeAnalysis.Editor.GoToDefinition;
 using Microsoft.CodeAnalysis.Editor.Host;
@@ -12,9 +11,8 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.GoToDefinition
     internal class CSharpGoToDefinitionService : AbstractGoToDefinitionService
     {
         [ImportingConstructor]
-        public CSharpGoToDefinitionService(
-            [Import(AllowDefault = true)] Lazy<IStreamingFindUsagesPresenter> streamingPresenterOpt)
-            : base(streamingPresenterOpt)
+        public CSharpGoToDefinitionService(IStreamingFindUsagesPresenter streamingPresenter)
+            : base(streamingPresenter)
         {
         }
     }

src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionService.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.Generic;
 using System.Linq;
 using System.Threading;
@@ -16,12 +15,11 @@ namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
     // GoToDefinition
     internal abstract class AbstractGoToDefinitionService : IGoToDefinitionService
     {
-        private readonly Lazy<IStreamingFindUsagesPresenter> _streamingPresenterOpt;
+        private readonly IStreamingFindUsagesPresenter _streamingPresenter;
 
-        protected AbstractGoToDefinitionService(
-            Lazy<IStreamingFindUsagesPresenter> streamingPresenterOpt)
+        protected AbstractGoToDefinitionService(IStreamingFindUsagesPresenter streamingPresenter)
         {
-            _streamingPresenterOpt = streamingPresenterOpt;
+            _streamingPresenter = streamingPresenter;
         }
 
         public async Task<IEnumerable<INavigableItem>> FindDefinitionsAsync(
@@ -54,7 +52,7 @@ public bool TryGoToDefinition(Document document, int position, CancellationToken
 
             return GoToDefinitionHelpers.TryGoToDefinition(symbol,
                 document.Project,
-                _streamingPresenterOpt,
+                _streamingPresenter,
                 thirdPartyNavigationAllowed: isThirdPartyNavigationAllowed,
                 throwOnHiddenDefinition: true,
                 cancellationToken: cancellationToken);

src/EditorFeatures/Core/GoToDefinition/GoToDefinitionHelpers.cs

@@ -95,18 +95,17 @@ internal static class GoToDefinitionHelpers
         public static bool TryGoToDefinition(
             ISymbol symbol,
             Project project,
-            Lazy<IStreamingFindUsagesPresenter> streamingPresenterOpt,
+            IStreamingFindUsagesPresenter streamingPresenter,
             CancellationToken cancellationToken,
             bool thirdPartyNavigationAllowed = true,
             bool throwOnHiddenDefinition = false)
         {
             var definitions = GetDefinitions(symbol, project, thirdPartyNavigationAllowed, cancellationToken);
 
-            var presenter = streamingPresenterOpt?.Value;
             var title = string.Format(EditorFeaturesResources._0_declarations,
                 FindUsagesHelpers.GetDisplayName(symbol));
 
-            return presenter.TryNavigateToOrPresentItemsAsync(
+            return streamingPresenter.TryNavigateToOrPresentItemsAsync(
                 project.Solution.Workspace, title, definitions).WaitAndGetResult(cancellationToken);
         }
 

src/EditorFeatures/Test2/GoToDefinition/GoToDefinitionCommandHandlerTests.vb

@@ -100,7 +100,7 @@ class C
                 Dim cursorBuffer = cursorDocument.TextBuffer
                 Dim document = workspace.CurrentSolution.GetDocument(cursorDocument.Id)
 
-                Dim goToDefService = New CSharpGoToDefinitionService(New Lazy(Of IStreamingFindUsagesPresenter)(Function() presenter))
+                Dim goToDefService = New CSharpGoToDefinitionService(presenter)
 
                 Dim waitContext = New TestUIThreadOperationContext(updatesBeforeCancel)
                 Dim commandHandler = New GoToDefinitionCommandHandler()

src/EditorFeatures/Test2/GoToDefinition/GoToDefinitionTests.vb

@@ -14,7 +14,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.GoToDefinition
     Public Class GoToDefinitionTests
         Friend Sub Test(workspaceDefinition As XElement,
                                         expectedResult As Boolean,
-                                        executeOnDocument As Func(Of Document, Integer, Lazy(Of IStreamingFindUsagesPresenter), Boolean))
+                                        executeOnDocument As Func(Of Document, Integer, IStreamingFindUsagesPresenter, Boolean))
             Using workspace = TestWorkspace.Create(
                     workspaceDefinition, exportProvider:=GoToTestHelpers.ExportProviderFactory.CreateExportProvider())
                 Dim solution = workspace.CurrentSolution
@@ -38,7 +38,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.GoToDefinition
 
                 Dim presenterCalled As Boolean = False
                 Dim presenter = New MockStreamingFindUsagesPresenter(Sub() presenterCalled = True)
-                Dim actualResult = executeOnDocument(document, cursorPosition, New Lazy(Of IStreamingFindUsagesPresenter)(Function() presenter))
+                Dim actualResult = executeOnDocument(document, cursorPosition, presenter)
 
                 Assert.Equal(expectedResult, actualResult)
 
@@ -103,7 +103,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.GoToDefinition
 
         Private Sub Test(workspaceDefinition As XElement, Optional expectedResult As Boolean = True)
             Test(workspaceDefinition, expectedResult,
-                Function(document As Document, cursorPosition As Integer, presenter As Lazy(Of IStreamingFindUsagesPresenter))
+                Function(document As Document, cursorPosition As Integer, presenter As IStreamingFindUsagesPresenter)
                     Dim goToDefService = If(document.Project.Language = LanguageNames.CSharp,
                         DirectCast(New CSharpGoToDefinitionService(presenter), IGoToDefinitionService),
                         New VisualBasicGoToDefinitionService(presenter))

src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionService.vb

@@ -11,8 +11,8 @@ Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
         Inherits AbstractGoToDefinitionService
 
         <ImportingConstructor>
-        Public Sub New(<Import(AllowDefault:=True)> streamingPresenterOpt As Lazy(Of IStreamingFindUsagesPresenter))
-            MyBase.New(streamingPresenterOpt)
+        Public Sub New(streamingPresenter As IStreamingFindUsagesPresenter)
+            MyBase.New(streamingPresenter)
         End Sub
     End Class
 End Namespace

src/VisualStudio/Core/Def/Implementation/Library/ObjectBrowser/AbstractObjectBrowserLibraryManager.cs

@@ -2,7 +2,6 @@
 
 using System;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using System.Threading;
 using Microsoft.CodeAnalysis;
@@ -41,7 +40,7 @@ internal abstract partial class AbstractObjectBrowserLibraryManager : AbstractLi
         private AbstractListItemFactory _listItemFactory;
         private object _classMemberGate = new object();
 
-        private readonly Lazy<IStreamingFindUsagesPresenter> _streamingPresenterOpt;
+        private readonly IStreamingFindUsagesPresenter _streamingPresenter;
         private readonly IThreadingContext _threadingContext;
 
         protected AbstractObjectBrowserLibraryManager(
@@ -61,7 +60,7 @@ internal abstract partial class AbstractObjectBrowserLibraryManager : AbstractLi
             Workspace.WorkspaceChanged += OnWorkspaceChanged;
 
             _libraryService = new Lazy<ILibraryService>(() => Workspace.Services.GetLanguageServices(_languageName).GetService<ILibraryService>());
-            _streamingPresenterOpt = componentModel.DefaultExportProvider.GetExports<IStreamingFindUsagesPresenter>().SingleOrDefault();
+            _streamingPresenter = componentModel.DefaultExportProvider.GetExportedValue<IStreamingFindUsagesPresenter>();
             _threadingContext = componentModel.DefaultExportProvider.GetExportedValue<IThreadingContext>();
         }
 
@@ -501,10 +500,8 @@ protected override bool TryExec(Guid commandGroup, uint commandId)
                 switch (commandId)
                 {
                     case (uint)VSConstants.VSStd97CmdID.FindReferences:
-                        var streamingPresenter = _streamingPresenterOpt?.Value;
                         var symbolListItem = _activeListItem as SymbolListItem;
-
-                        if (streamingPresenter != null && symbolListItem?.ProjectId != null)
+                        if (symbolListItem?.ProjectId != null)
                         {
                             var project = this.Workspace.CurrentSolution.GetProject(symbolListItem.ProjectId);
                             if (project != null)
@@ -514,7 +511,7 @@ protected override bool TryExec(Guid commandGroup, uint commandId)
                                 // and the references will be asynchronously added to the FindReferences
                                 // window as they are computed.  The user also knows something is happening
                                 // as the window, with the progress-banner will pop up immediately.
-                                var task = FindReferencesAsync(streamingPresenter, symbolListItem, project);
+                                var task = FindReferencesAsync(_streamingPresenter, symbolListItem, project);
                                 return true;
                             }
                         }

src/VisualStudio/Core/Impl/RoslynVisualStudioWorkspace.cs

@@ -28,6 +28,10 @@ namespace Microsoft.VisualStudio.LanguageServices
     [Export(typeof(VisualStudioWorkspaceImpl))]
     internal class RoslynVisualStudioWorkspace : VisualStudioWorkspaceImpl
     {
+        /// <remarks>
+        /// Must be lazily constructed since the <see cref="IStreamingFindUsagesPresenter"/> implementation imports a
+        /// backreference to <see cref="VisualStudioWorkspace"/>.
+        /// </remarks>
         private readonly Lazy<IStreamingFindUsagesPresenter> _streamingPresenter;
 
         [ImportingConstructor]
@@ -116,7 +120,7 @@ private static bool TryResolveSymbol(ISymbol symbol, Project project, Cancellati
 
             return GoToDefinitionHelpers.TryGoToDefinition(
                 searchSymbol, searchProject,
-                _streamingPresenter, cancellationToken);
+                _streamingPresenter.Value, cancellationToken);
         }
 
         public override bool TryFindAllReferences(ISymbol symbol, Project project, CancellationToken cancellationToken)

src/VisualStudio/Core/Test/GoToDefinition/GoToDefinitionApiTests.vb

@@ -3,7 +3,6 @@
 Imports System.Threading
 Imports Microsoft.CodeAnalysis
 Imports Microsoft.CodeAnalysis.Editor.GoToDefinition
-Imports Microsoft.CodeAnalysis.Editor.Host
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
 Imports Microsoft.CodeAnalysis.Test.Utilities
@@ -42,7 +41,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.GoToDefinition
                 WpfTestRunner.RequireWpfFact($"{NameOf(GoToDefinitionHelpers)}.{NameOf(GoToDefinitionHelpers.TryGoToDefinition)} assumes it's on the UI thread with a {NameOf(TaskExtensions.WaitAndGetResult)} call")
                 Dim success = GoToDefinitionHelpers.TryGoToDefinition(
                     symbolInfo.Symbol, document.Project,
-                    New Lazy(Of IStreamingFindUsagesPresenter)(Function() presenter),
+                    presenter,
                     thirdPartyNavigationAllowed:=True, throwOnHiddenDefinition:=False,
                     cancellationToken:=CancellationToken.None)