Merge pull request #14016 from vslsnap/merge-dev15-preview-5-into-master20160923-150132

Merge dev15-preview-5 into master

build/Targets/VSL.Imports.targets

@@ -284,6 +284,7 @@
            or '%(FileName)' == 'Microsoft.VisualStudio.Shell.Interop.12.0'
            or '%(FileName)' == 'Microsoft.VisualStudio.Shell.Interop.12.1.DesignTime'
            or '%(FileName)' == 'Microsoft.VisualStudio.Shell.Interop.14.0.DesignTime'
+           or '%(FileName)' == 'Microsoft.VisualStudio.Shell.Interop.15.0.DesignTime'
            or '%(Filename)' == 'Microsoft.VisualStudio.Imaging.Interop.14.0.DesignTime'
            or '%(FileName)' == 'Microsoft.VisualStudio.TextManager.Interop.12.1.DesignTime'
            or '%(FileName)' == 'Microsoft.Internal.VisualStudio.Shell.Interop.14.0.DesignTime'

src/VisualStudio/CSharp/Impl/LanguageService/CSharpLanguageService_ICSharpProjectHost.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.Diagnostics;
 using System.IO;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim;
 using Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.Interop;
 using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
+using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.Legacy;
 using Microsoft.VisualStudio.LanguageServices.Implementation.TaskList;
+using Microsoft.VisualStudio.LanguageServices.ProjectSystem;
 using Microsoft.VisualStudio.Shell.Interop;
 
 namespace Microsoft.VisualStudio.LanguageServices.CSharp.LanguageService
@@ -16,6 +19,8 @@ internal partial class CSharpLanguageService : ICSharpProjectHost
         public void BindToProject(ICSharpProjectRoot projectRoot, IVsHierarchy hierarchy)
         {
             var projectName = Path.GetFileName(projectRoot.GetFullProjectName()); // GetFullProjectName returns the path to the project file w/o the extension?
+            Workspace.ProjectTracker.TryDisconnectExistingDeferredProject(hierarchy, projectName);
+
             var project = new CSharpProjectShimWithServices(
                 projectRoot,
                 this.Workspace.ProjectTracker,

src/VisualStudio/CSharp/Impl/ProjectSystemShim/CSharpProjectShim.ICSharpProjectSite.cs

@@ -64,24 +64,7 @@ public void OnSourceFileAdded(string filename)
             //    ? SourceCodeKind.Script
             //    : SourceCodeKind.Regular;
             var sourceCodeKind = SourceCodeKind.Regular;
-
-            IVsHierarchy foundHierarchy;
-            uint itemId;
-            if (ErrorHandler.Succeeded(_projectRoot.GetHierarchyAndItemID(filename, out foundHierarchy, out itemId)))
-            {
-                Debug.Assert(foundHierarchy == this.Hierarchy);
-            }
-            else
-            {
-                // Unfortunately, the project system does pass us some files which aren't part of
-                // the project as far as the hierarchy and itemid are concerned.  We'll just used
-                // VSITEMID.Nil for them.
-
-                foundHierarchy = null;
-                itemId = (uint)VSConstants.VSITEMID.Nil;
-            }
-
-            AddFile(filename, sourceCodeKind, itemId);
+            AddFile(filename, sourceCodeKind);
         }
 
         public void OnSourceFileRemoved(string filename)

src/VisualStudio/CSharp/Test/ProjectSystemShim/CPS/CSharpReferencesTests.cs

@@ -46,9 +46,7 @@ public void AddRemoveProjectAndMetadataReference_CPS()
                 ((IWorkspaceProjectContext)project4).BinOutputPath = @"C:\project4.dll";
                 Assert.Equal(@"C:\project4.dll", project4.BinOutputPath);
 
-                // This is currently broken by https://github.com/dotnet/roslyn/issues/12707
-                // Reverse the below assert to Assert.True once the above bug is fixed.
-                Assert.False(project3.GetCurrentProjectReferences().Any(pr => pr.ProjectId == project4.Id));
+                Assert.True(project3.GetCurrentProjectReferences().Any(pr => pr.ProjectId == project4.Id));
 
                 // Remove project reference
                 project3.RemoveProjectReference(project1);

src/VisualStudio/Core/Def/Implementation/Extensions/VisualStudioWorkspaceImplExtensions.cs

@@ -78,11 +78,9 @@ public static bool TryGetImageListAndIndex(this VisualStudioWorkspaceImpl worksp
 
         public static bool TryGetImageListAndIndex(this VisualStudioWorkspaceImpl workspace, IVsImageService2 imageService, ProjectId id, out IntPtr imageList, out ushort index)
         {
-            var project = workspace.GetHostProject(id);
-            if (project != null)
+            var hierarchy = workspace.GetHostProject(id)?.Hierarchy;
+            if (hierarchy != null)
             {
-                var hierarchy = project.Hierarchy;
-
                 return TryGetImageListAndIndex(hierarchy, imageService, VSConstants.VSITEMID_ROOT, out imageList, out index);
             }
 

src/VisualStudio/Core/Def/Implementation/ProjectSystem/AbstractProject.cs

@@ -187,6 +187,9 @@ internal abstract partial class AbstractProject : ForegroundThreadAffinitizedObj
 
         private ICommandLineParserService CommandLineParserService { get; }
 
+        /// <summary>
+        /// The <see cref="IVsHierarchy"/> for this project.  NOTE: May be null in Deferred Project Load cases.
+        /// </summary>
         public IVsHierarchy Hierarchy { get; }
 
         /// <summary>
@@ -892,15 +895,19 @@ private static void OnAdditionalDocumentUpdatedOnDisk(object sender, EventArgs e
             }
         }
 
-        protected void AddFile(string filename, SourceCodeKind sourceCodeKind, Func<IVisualStudioHostDocument, bool> getIsCurrentContext, IReadOnlyList<string> folderNames)
+        protected void AddFile(
+            string filename,
+            SourceCodeKind sourceCodeKind,
+            Func<IVisualStudioHostDocument, bool> getIsCurrentContext,
+            Func<uint, IReadOnlyList<string>> getFolderNames)
         {
             // We can currently be on a background thread.
             // So, hookup the handlers when creating the standard text document, as we might receive these handler notifications on the UI thread.
             var document = this.DocumentProvider.TryGetDocumentForFile(
                 this,
-                folderNames,
                 filePath: filename,
                 sourceCodeKind: sourceCodeKind,
+                getFolderNames: getFolderNames,
                 canUseTextBuffer: CanUseTextBuffer,
                 updatedOnDiskHandler: s_documentUpdatedOnDiskEventHandler,
                 openedHandler: s_documentOpenedEventHandler,

src/VisualStudio/Core/Def/Implementation/ProjectSystem/AbstractProject_Analyzers.cs

@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.VisualStudio.ComponentModelHost;
 using Microsoft.VisualStudio.Shell.Interop;
+using Roslyn.Utilities;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem
 {
@@ -125,9 +126,9 @@ public void AddAdditionalFile(string additionalFilePath, Func<IVisualStudioHostD
         {
             var document = this.DocumentProvider.TryGetDocumentForFile(
                 this,
-                ImmutableArray<string>.Empty,
                 filePath: additionalFilePath,
                 sourceCodeKind: SourceCodeKind.Regular,
+                getFolderNames: _ => SpecializedCollections.EmptyReadOnlyList<string>(),
                 canUseTextBuffer: _ => true,
                 updatedOnDiskHandler: s_additionalDocumentUpdatedOnDiskEventHandler,
                 openedHandler: s_additionalDocumentOpenedEventHandler,

src/VisualStudio/Core/Def/Implementation/ProjectSystem/CPS/IWorkspaceProjectContextFactory.cs

@@ -19,7 +19,7 @@ internal interface IWorkspaceProjectContextFactory
         /// <param name="projectDisplayName">Display name for the project.</param>
         /// <param name="projectFilePath">Full path to the project file for the project.</param>
         /// <param name="projectGuid">Project guid.</param>
-        /// <param name="hierarchy"><see cref="IVsHierarchy"/> for the project.</param>
+        /// <param name="hierarchy"><see cref="IVsHierarchy"/> for the project, an be null in deferred project load cases.</param>
         /// <param name="binOutputPath">Initial project binary output path.</param>
         IWorkspaceProjectContext CreateProjectContext(string languageName, string projectDisplayName, string projectFilePath, Guid projectGuid, object hierarchy, string binOutputPath);
     }

src/VisualStudio/Core/Def/Implementation/ProjectSystem/DocumentProvider.StandardTextDocument.cs

@@ -45,11 +45,15 @@ private class StandardTextDocument : ForegroundThreadAffinitizedObject, IVisualS
             public event EventHandler<bool> Opened;
             public event EventHandler<bool> Closing;
 
+            /// <summary>
+            /// Creates a <see cref="StandardTextDocument"/>.
+            /// <para>Note: getFolderNames maps from a VSITEMID to the folders this document should be contained in.</para>
+            /// </summary>
             public StandardTextDocument(
                 DocumentProvider documentProvider,
                 IVisualStudioHostProject project,
                 DocumentKey documentKey,
-                IReadOnlyList<string> folderNames,
+                Func<uint, IReadOnlyList<string>> getFolderNames,
                 SourceCodeKind sourceCodeKind,
                 ITextUndoHistoryRegistry textUndoHistoryRegistry,
                 IVsFileChangeEx fileChangeService,
@@ -63,13 +67,17 @@ private class StandardTextDocument : ForegroundThreadAffinitizedObject, IVisualS
 
                 this.Project = project;
                 this.Id = id ?? DocumentId.CreateNewId(project.Id, documentKey.Moniker);
-                this.Folders = folderNames;
+                _itemMoniker = documentKey.Moniker;
+
+                var itemid = this.GetItemId();
+                this.Folders = itemid == (uint)VSConstants.VSITEMID.Nil
+                    ? SpecializedCollections.EmptyReadOnlyList<string>()
+                    : getFolderNames(itemid);
 
                 _documentProvider = documentProvider;
 
                 this.Key = documentKey;
                 this.SourceCodeKind = sourceCodeKind;
-                _itemMoniker = documentKey.Moniker;
                 _textUndoHistoryRegistry = textUndoHistoryRegistry;
                 _fileChangeTracker = new FileChangeTracker(fileChangeService, this.FilePath);
                 _fileChangeTracker.UpdatedOnDisk += OnUpdatedOnDisk;
@@ -251,7 +259,7 @@ public uint GetItemId()
             {
                 AssertIsForeground();
 
-                if (_itemMoniker == null)
+                if (_itemMoniker == null || Project.Hierarchy == null)
                 {
                     return (uint)VSConstants.VSITEMID.Nil;
                 }

src/VisualStudio/Core/Def/Implementation/ProjectSystem/DocumentProvider.cs

@@ -95,10 +95,10 @@ internal abstract partial class DocumentProvider : ForegroundThreadAffinitizedOb
         /// </summary>
         public IVisualStudioHostDocument TryGetDocumentForFile(
             IVisualStudioHostProject hostProject,
-            IReadOnlyList<string> folderNames,
             string filePath,
             SourceCodeKind sourceCodeKind,
             Func<ITextBuffer, bool> canUseTextBuffer,
+            Func<uint, IReadOnlyList<string>> getFolderNames,
             EventHandler updatedOnDiskHandler = null,
             EventHandler<bool> openedHandler = null,
             EventHandler<bool> closingHandler = null)
@@ -163,7 +163,7 @@ internal abstract partial class DocumentProvider : ForegroundThreadAffinitizedOb
                     this,
                     hostProject,
                     documentKey,
-                    folderNames,
+                    getFolderNames,
                     sourceCodeKind,
                     _textUndoHistoryRegistry,
                     _fileChangeService,

src/VisualStudio/Core/Def/Implementation/ProjectSystem/IDeferredProjectWorkspaceService.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.Collections.Immutable;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Host;
+using Roslyn.Utilities;
+
+namespace Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem
+{
+    internal interface IDeferredProjectWorkspaceService : IWorkspaceService
+    {
+        bool IsDeferredProjectLoadEnabled { get; }
+
+        /// <summary>
+        /// Returns a mapping of project file path to information about that project.
+        /// </summary>
+        Task<IReadOnlyDictionary<string, DeferredProjectInformation>> GetDeferredProjectInfoForConfigurationAsync(
+            string solutionConfiguration,
+            CancellationToken cancellationToken);
+    }
+
+    internal struct DeferredProjectInformation
+    {
+        public DeferredProjectInformation(
+            string targetPath,
+            ImmutableArray<string> commandLineArgs,
+            ImmutableArray<string> referencedProjectFilePaths)
+        {
+            TargetPath = targetPath;
+            CommandLineArguments = commandLineArgs;
+            ReferencedProjectFilePaths = referencedProjectFilePaths;
+        }
+
+        /// <summary>
+        /// The full path to the binary this project would create if built *by msbuild*.
+        /// May be different than the /out argument in <see cref="CommandLineArguments"/>.
+        /// </summary>
+        public string TargetPath { get; }
+
+        /// <summary>
+        /// The set of command line arguments that can be used to build this project.
+        /// </summary>
+
+        public ImmutableArray<string> CommandLineArguments { get; }
+
+        /// <summary>
+        /// The paths to referenced projects.
+        /// </summary>
+        public ImmutableArray<string> ReferencedProjectFilePaths { get; }
+
+    }
+}

src/VisualStudio/Core/Def/Implementation/ProjectSystem/IVisualStudioHostProject.cs

@@ -15,6 +15,9 @@ internal interface IVisualStudioHostProject
         ProjectId Id { get; }
         string Language { get; }
 
+        /// <summary>
+        /// The <see cref="IVsHierarchy"/> for this project.  NOTE: May be null in Deferred Project Load cases.
+        /// </summary>
         IVsHierarchy Hierarchy { get; }
         Guid Guid { get; }
 

src/VisualStudio/Core/Def/Implementation/ProjectSystem/Legacy/AbstractLegacyProject.cs

@@ -45,8 +45,11 @@ internal abstract partial class AbstractLegacyProject : AbstractProject
                   hostDiagnosticUpdateSourceOpt: hostDiagnosticUpdateSourceOpt,
                   commandLineParserServiceOpt: commandLineParserServiceOpt)
         {
-            ConnectHierarchyEvents();
-            this.IsWebSite = GetIsWebsiteProject(hierarchy);
+            if (Hierarchy != null)
+            {
+                ConnectHierarchyEvents();
+                this.IsWebSite = GetIsWebsiteProject(Hierarchy);
+            }
 
             // Initialize command line arguments.
             base.SetArguments(commandLine: string.Empty);
@@ -65,10 +68,10 @@ public override void Disconnect()
             DisconnectHierarchyEvents();
         }
 
-        protected void AddFile(string filename, SourceCodeKind sourceCodeKind, uint itemId)
+        protected void AddFile(string filename, SourceCodeKind sourceCodeKind)
         {
             Func<IVisualStudioHostDocument, bool> getIsCurrentContext = document => LinkedFileUtilities.IsCurrentContextHierarchy(document, RunningDocumentTable);
-            AddFile(filename, sourceCodeKind, getIsCurrentContext, GetFolderNames(itemId));
+            AddFile(filename, sourceCodeKind, getIsCurrentContext, GetFolderNames);
         }
 
         protected void SetOutputPathAndRelatedData(string objOutputPath)
@@ -124,7 +127,7 @@ private static string GetProjectDisplayName(IVsHierarchy hierarchy)
             return hierarchy.TryGetName(out name) ? name : null;
         }
 
-        private static string GetProjectFilePath(IVsHierarchy hierarchy)
+        internal static string GetProjectFilePath(IVsHierarchy hierarchy)
         {
             string filePath;
             return ErrorHandler.Succeeded(((IVsProject3)hierarchy).GetMkDocument((uint)VSConstants.VSITEMID.Root, out filePath)) ? filePath : null;

src/VisualStudio/Core/Def/Implementation/ProjectSystem/MiscellaneousFilesWorkspace.cs

@@ -311,9 +311,9 @@ private void AttachToDocument(uint docCookie, string moniker)
             // Now try to find the document. We accept any text buffer, since we've already verified it's an appropriate file in ShouldIncludeFile.
             var document = _documentProvider.TryGetDocumentForFile(
                 hostProject,
-                ImmutableArray<string>.Empty,
                 moniker,
                 parseOptions.Kind,
+                getFolderNames: _ => SpecializedCollections.EmptyReadOnlyList<string>(),
                 canUseTextBuffer: _ => true);
 
             // If the buffer has not yet been initialized, we won't get a document.

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioProjectTracker.cs

@@ -3,13 +3,19 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Diagnostics;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 using System.Windows.Threading;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
+using Microsoft.CodeAnalysis.Host;
 using Microsoft.Internal.VisualStudio.Shell.Interop;
+using Microsoft.VisualStudio.ComponentModelHost;
+using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.Legacy;
+using Microsoft.VisualStudio.LanguageServices.ProjectSystem;
 using Microsoft.VisualStudio.Shell.Interop;
 using Roslyn.Utilities;
 
@@ -29,6 +35,8 @@ internal sealed partial class VisualStudioProjectTracker : ForegroundThreadAffin
         #region Mutable fields accessed only from foreground thread - don't need locking for access (all accessing methods must have AssertIsForeground).
         private readonly List<WorkspaceHostState> _workspaceHosts;
 
+        private readonly HostWorkspaceServices _workspaceServices;
+
         /// <summary>
         /// The list of projects loaded in this batch between <see cref="IVsSolutionLoadEvents.OnBeforeLoadProjectBatch" /> and
         /// <see cref="IVsSolutionLoadEvents.OnAfterLoadProjectBatch(bool)"/>.
@@ -100,7 +108,7 @@ void IVisualStudioHostProjectContainer.NotifyNonDocumentOpenedForProject(IVisual
             StartPushingToWorkspaceAndNotifyOfOpenDocuments(SpecializedCollections.SingletonEnumerable(abstractProject));
         }
 
-        public VisualStudioProjectTracker(IServiceProvider serviceProvider)
+        public VisualStudioProjectTracker(IServiceProvider serviceProvider, HostWorkspaceServices workspaceServices)
             : base(assertIsForeground: true)
         {
             _projectMap = new Dictionary<ProjectId, AbstractProject>();
@@ -108,6 +116,7 @@ public VisualStudioProjectTracker(IServiceProvider serviceProvider)
 
             _serviceProvider = serviceProvider;
             _workspaceHosts = new List<WorkspaceHostState>(capacity: 1);
+            _workspaceServices = workspaceServices;
 
             _vsSolution = (IVsSolution)serviceProvider.GetService(typeof(SVsSolution));
             _runningDocumentTable = (IVsRunningDocumentTable4)serviceProvider.GetService(typeof(SVsRunningDocumentTable));
@@ -565,5 +574,21 @@ internal void RemoveProjectByBinPath(string filePath, AbstractProject project)
                 }
             }
         }
+
+        internal void TryDisconnectExistingDeferredProject(IVsHierarchy hierarchy, string projectName)
+        {
+            var projectPath = AbstractLegacyProject.GetProjectFilePath(hierarchy);
+            var projectId = GetOrCreateProjectIdForPath(projectPath, projectName);
+
+            // If we created a project for this while in deferred project load mode, let's close it
+            // now that we're being asked to make a "real" project for it, so that we'll prefer the
+            // "real" project
+            if (_workspaceServices.GetService<IDeferredProjectWorkspaceService>()?.IsDeferredProjectLoadEnabled == true)
+            {
+                var existingProject = GetProject(projectId);
+                Debug.Assert(existingProject is IWorkspaceProjectContext);
+                existingProject?.Disconnect();
+            }
+        }
     }
 }

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioProjectTracker_IVsSolutionEvents.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.Linq;
+using System.Threading;
 using Microsoft.VisualStudio.Shell.Interop;
 using Roslyn.Utilities;
 
@@ -19,6 +21,14 @@ int IVsSolutionEvents.OnAfterOpenProject(IVsHierarchy pHierarchy, int fAdded)
 
         int IVsSolutionEvents.OnAfterOpenSolution(object pUnkReserved, int fNewSolution)
         {
+            AssertIsForeground();
+
+            var deferredProjectWorkspaceService = _workspaceServices.GetService<IDeferredProjectWorkspaceService>();
+            if (deferredProjectWorkspaceService?.IsDeferredProjectLoadEnabled == true)
+            {
+                LoadSolutionFromMSBuildAsync(deferredProjectWorkspaceService, _solutionParsingCancellationTokenSource.Token).FireAndForget();
+            }
+
             return VSConstants.S_OK;
         }
 
@@ -60,6 +70,11 @@ int IVsSolutionEvents.OnBeforeCloseSolution(object pUnkReserved)
 
             _solutionLoadComplete = false;
 
+            // Cancel any background solution parsing. NOTE: This means that that work needs to
+            // check the token periodically, and whenever resuming from an "await"
+            _solutionParsingCancellationTokenSource.Cancel();
+            _solutionParsingCancellationTokenSource = new CancellationTokenSource();
+
             return VSConstants.S_OK;
         }
 
@@ -67,6 +82,17 @@ int IVsSolutionEvents.OnAfterCloseSolution(object pUnkReserved)
         {
             AssertIsForeground();
 
+            var deferredProjectWorkspaceService = _workspaceServices.GetService<IDeferredProjectWorkspaceService>();
+            if (deferredProjectWorkspaceService?.IsDeferredProjectLoadEnabled == true)
+            {
+                // Copy to avoid modifying the collection while enumerating
+                var loadedProjects = ImmutableProjects.ToList();
+                foreach (var p in loadedProjects)
+                {
+                    p.Disconnect();
+                }
+            }
+
             lock (_gate)
             {
                 Contract.ThrowIfFalse(_projectMap.Count == 0);

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioProjectTracker_IVsSolutionLoadEvents.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.Collections.Immutable;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Host;
 using Microsoft.VisualStudio.ComponentModelHost;
+using Microsoft.VisualStudio.LanguageServices.ProjectSystem;
 using Microsoft.VisualStudio.Shell.Interop;
+using Roslyn.Utilities;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem
 {
     internal partial class VisualStudioProjectTracker : IVsSolutionLoadEvents
     {
+        // Temporary for prototyping purposes
+        private IVsOutputWindowPane _pane;
+
+        /// <summary>
+        /// Used to cancel our background solution parse if we get a solution close event from VS.
+        /// </summary>
+        private CancellationTokenSource _solutionParsingCancellationTokenSource = new CancellationTokenSource();
+
         int IVsSolutionLoadEvents.OnBeforeOpenSolution(string pszSolutionFilename)
         {
             return VSConstants.S_OK;
         }
 
+        private async Task LoadSolutionFromMSBuildAsync(
+            IDeferredProjectWorkspaceService deferredProjectWorkspaceService,
+            CancellationToken cancellationToken)
+        {
+            AssertIsForeground();
+            InitializeOutputPane();
+
+            // Continue on the UI thread for these operations, since we are touching the VisualStudioWorkspace, etc.
+            await PopulateWorkspaceFromDeferredProjectInfoAsync(deferredProjectWorkspaceService, cancellationToken).ConfigureAwait(true);
+        }
+
+        [Conditional("DEBUG")]
+        private void InitializeOutputPane()
+        {
+            var outputWindow = (IVsOutputWindow)_serviceProvider.GetService(typeof(SVsOutputWindow));
+            var paneGuid = new Guid("07aaa8e9-d776-47d6-a1be-5ce00332d74d");
+            if (ErrorHandler.Succeeded(outputWindow.CreatePane(ref paneGuid, "Roslyn DPL Status", fInitVisible: 1, fClearWithSolution: 1)) &&
+                ErrorHandler.Succeeded(outputWindow.GetPane(ref paneGuid, out _pane)) && _pane != null)
+            {
+                _pane.Activate();
+            }
+        }
+
         int IVsSolutionLoadEvents.OnBeforeBackgroundSolutionLoadBegins()
         {
             return VSConstants.S_OK;
@@ -51,6 +95,228 @@ int IVsSolutionLoadEvents.OnAfterBackgroundSolutionLoadComplete()
         {
             AssertIsForeground();
 
+            // In Non-DPL scenarios, this indicates that ASL is complete, and we should push any
+            // remaining information we have to the Workspace.  If DPL is enabled, this is never
+            // called.
+            FinishLoad();
+
+            return VSConstants.S_OK;
+        }
+
+        private async Task PopulateWorkspaceFromDeferredProjectInfoAsync(
+            IDeferredProjectWorkspaceService deferredProjectWorkspaceService,
+            CancellationToken cancellationToken)
+        {
+            // NOTE: We need to check cancellationToken after each await, in case the user has
+            // already closed the solution.
+            AssertIsForeground();
+
+            var componentModel = _serviceProvider.GetService(typeof(SComponentModel)) as IComponentModel;
+            var workspaceProjectContextFactory = componentModel.GetService<IWorkspaceProjectContextFactory>();
+
+            var dte = _serviceProvider.GetService(typeof(EnvDTE.DTE)) as EnvDTE.DTE;
+            var solutionConfig = (EnvDTE80.SolutionConfiguration2)dte.Solution.SolutionBuild.ActiveConfiguration;
+
+            OutputToOutputWindow($"Getting project information - start");
+            var start = DateTimeOffset.UtcNow;
+            // Capture the context so that we come back on the UI thread, and do the actual project creation there.
+            var projectInfos = await deferredProjectWorkspaceService.GetDeferredProjectInfoForConfigurationAsync(
+                $"{solutionConfig.Name}|{solutionConfig.PlatformName}",
+                cancellationToken).ConfigureAwait(true);
+            AssertIsForeground();
+
+            cancellationToken.ThrowIfCancellationRequested();
+            OutputToOutputWindow($"Getting project information - done (took {DateTimeOffset.UtcNow - start})");
+
+            OutputToOutputWindow($"Creating projects - start");
+            start = DateTimeOffset.UtcNow;
+            var targetPathsToProjectPaths = BuildTargetPathMap(projectInfos);
+            foreach (var projectFilename in projectInfos.Keys)
+            {
+                cancellationToken.ThrowIfCancellationRequested();
+                GetOrCreateProjectFromArgumentsAndReferences(
+                    workspaceProjectContextFactory,
+                    projectFilename,
+                    projectInfos,
+                    targetPathsToProjectPaths);
+            }
+            OutputToOutputWindow($"Creating projects - done (took {DateTimeOffset.UtcNow - start})");
+
+            OutputToOutputWindow($"Pushing to workspace - start");
+            start = DateTimeOffset.UtcNow;
+            FinishLoad();
+            OutputToOutputWindow($"Pushing to workspace - done (took {DateTimeOffset.UtcNow - start})");
+        }
+
+        private static ImmutableDictionary<string, string> BuildTargetPathMap(IReadOnlyDictionary<string, DeferredProjectInformation> projectInfos)
+        {
+            var builder = ImmutableDictionary.CreateBuilder<string, string>(StringComparer.OrdinalIgnoreCase);
+            foreach (var item in projectInfos)
+            {
+                var targetPath = item.Value.TargetPath;
+                if (targetPath != null)
+                {
+                    if (!builder.ContainsKey(targetPath))
+                    {
+                        builder[targetPath] = item.Key;
+                    }
+                    else
+                    {
+                        Debug.Fail($"Already have a target path of '{item.Value.TargetPath}', with value '{builder[item.Value.TargetPath]}'.");
+                    }
+                }
+            }
+            return builder.ToImmutable();
+        }
+
+        [Conditional("DEBUG")]
+        private void OutputToOutputWindow(string message)
+        {
+            _pane?.OutputString(message + Environment.NewLine);
+        }
+
+        private AbstractProject GetOrCreateProjectFromArgumentsAndReferences(
+            IWorkspaceProjectContextFactory workspaceProjectContextFactory,
+            string projectFilename,
+            IReadOnlyDictionary<string, DeferredProjectInformation> allProjectInfos,
+            IReadOnlyDictionary<string, string> targetPathsToProjectPaths)
+        {
+            var languageName = GetLanguageOfProject(projectFilename);
+            if (languageName == null)
+            {
+                return null;
+            }
+
+            DeferredProjectInformation projectInfo;
+            if (!allProjectInfos.TryGetValue(projectFilename, out projectInfo))
+            {
+                // This could happen if we were called recursively about a dangling P2P reference
+                // that isn't actually in the solution.
+                return null;
+            }
+
+            var commandLineParser = _workspaceServices.GetLanguageServices(languageName).GetService<ICommandLineParserService>();
+            var projectDirectory = Path.GetDirectoryName(projectFilename);
+            var commandLineArguments = commandLineParser.Parse(
+                projectInfo.CommandLineArguments,
+                projectDirectory,
+                isInteractive: false,
+                sdkDirectory: RuntimeEnvironment.GetRuntimeDirectory());
+
+            // TODO: Should come from sln file?
+            var projectName = Path.GetFileNameWithoutExtension(projectFilename);
+            var projectId = GetOrCreateProjectIdForPath(projectFilename, projectName);
+
+            // See if we've already created this project and we're now in a recursive call to
+            // hook up a P2P ref.
+            AbstractProject project;
+            if (_projectMap.TryGetValue(projectId, out project))
+            {
+                return project;
+            }
+
+            OutputToOutputWindow($"\tCreating '{projectName}':\t{commandLineArguments.SourceFiles.Length} source files,\t{commandLineArguments.MetadataReferences.Length} references.");
+            var solution5 = _serviceProvider.GetService(typeof(SVsSolution)) as IVsSolution5;
+            var projectGuid = solution5.GetGuidOfProjectFile(projectFilename);
+            var projectContext = workspaceProjectContextFactory.CreateProjectContext(
+                languageName,
+                projectName,
+                projectFilename,
+                projectGuid: projectGuid,
+                hierarchy: null,
+                binOutputPath: projectInfo.TargetPath);
+
+            projectContext.SetOptions(projectInfo.CommandLineArguments.Join(" "));
+
+            foreach (var sourceFile in commandLineArguments.SourceFiles)
+            {
+                projectContext.AddSourceFile(sourceFile.Path);
+            }
+
+            foreach (var sourceFile in commandLineArguments.AdditionalFiles)
+            {
+                projectContext.AddAdditionalFile(sourceFile.Path);
+            }
+
+            var addedProjectReferences = new HashSet<string>();
+            foreach (var projectReferencePath in projectInfo.ReferencedProjectFilePaths)
+            {
+                var referencedProject = ImmutableProjects.SingleOrDefault(p => StringComparer.OrdinalIgnoreCase.Equals(p.ProjectFilePath, projectReferencePath));
+                if (referencedProject == null)
+                {
+                    referencedProject = GetOrCreateProjectFromArgumentsAndReferences(
+                        workspaceProjectContextFactory,
+                        projectReferencePath,
+                        allProjectInfos,
+                        targetPathsToProjectPaths);
+                }
+
+                var referencedProjectContext = referencedProject as IWorkspaceProjectContext;
+                if (referencedProjectContext != null)
+                {
+                    // TODO: Can we get the properties from corresponding metadata reference in
+                    // commandLineArguments?
+                    addedProjectReferences.Add(projectReferencePath);
+                    projectContext.AddProjectReference(
+                        referencedProjectContext,
+                        new MetadataReferenceProperties());
+                }
+                else if (referencedProject != null)
+                {
+                    // This project was already created by the regular project system. See if we
+                    // can find the matching project somehow.
+                    var existingReferenceOutputPath = referencedProject?.BinOutputPath;
+                    if (existingReferenceOutputPath != null)
+                    {
+                        addedProjectReferences.Add(projectReferencePath);
+                        projectContext.AddMetadataReference(
+                            existingReferenceOutputPath,
+                            new MetadataReferenceProperties());
+                    }
+                }
+                else
+                {
+                    // We don't know how to create this project.  Another language or something?
+                    OutputToOutputWindow($"Failed to create a project for '{projectReferencePath}'.");
+                }
+            }
+
+            foreach (var reference in commandLineArguments.MetadataReferences)
+            {
+                string possibleProjectReference;
+                if (targetPathsToProjectPaths.TryGetValue(reference.Reference, out possibleProjectReference) &&
+                    addedProjectReferences.Contains(possibleProjectReference))
+                {
+                    // We already added a P2P reference for this, we don't need to add the file reference too.
+                    continue;
+                }
+
+                projectContext.AddMetadataReference(reference.Reference, reference.Properties);
+            }
+
+            foreach (var reference in commandLineArguments.AnalyzerReferences)
+            {
+                projectContext.AddAnalyzerReference(reference.FilePath);
+            }
+
+            return (AbstractProject)projectContext;
+        }
+
+        private static string GetLanguageOfProject(string projectFilename)
+        {
+            switch (Path.GetExtension(projectFilename))
+            {
+                case ".csproj":
+                    return LanguageNames.CSharp;
+                case ".vbproj":
+                    return LanguageNames.VisualBasic;
+                default:
+                    return null;
+            };
+        }
+
+        private void FinishLoad()
+        {
             // We are now completely done, so let's simply ensure all projects are added.
             StartPushingToWorkspaceAndNotifyOfOpenDocuments_Foreground(this.ImmutableProjects);
 
@@ -59,8 +325,6 @@ int IVsSolutionLoadEvents.OnAfterBackgroundSolutionLoadComplete()
 
             // Check that the set of analyzers is complete and consistent.
             GetAnalyzerDependencyCheckingService()?.CheckForConflictsAsync();
-
-            return VSConstants.S_OK;
         }
 
         private AnalyzerDependencyCheckingService GetAnalyzerDependencyCheckingService()

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs

@@ -79,7 +79,7 @@ internal static HostServices CreateHostServices(SVsServiceProvider serviceProvid
 
         protected void InitializeStandardVisualStudioWorkspace(SVsServiceProvider serviceProvider, SaveEventsService saveEventsService)
         {
-            var projectTracker = new VisualStudioProjectTracker(serviceProvider);
+            var projectTracker = new VisualStudioProjectTracker(serviceProvider, this.Services);
 
             // Ensure the document tracking service is initialized on the UI thread
             var documentTrackingService = this.Services.GetService<IDocumentTrackingService>();
@@ -145,8 +145,36 @@ private bool TryGetHostProject(ProjectId projectId, out IVisualStudioHostProject
             Microsoft.CodeAnalysis.Solution newSolution,
             IProgressTracker progressTracker)
         {
+            var projectChanges = newSolution.GetChanges(this.CurrentSolution).GetProjectChanges().ToList();
+            var projectsToLoad = new HashSet<Guid>();
+            foreach (var pc in projectChanges)
+            {
+                if (pc.GetAddedAdditionalDocuments().Any() ||
+                    pc.GetAddedAnalyzerReferences().Any() ||
+                    pc.GetAddedDocuments().Any() ||
+                    pc.GetAddedMetadataReferences().Any() ||
+                    pc.GetAddedProjectReferences().Any() ||
+                    pc.GetRemovedAdditionalDocuments().Any() ||
+                    pc.GetRemovedAnalyzerReferences().Any() ||
+                    pc.GetRemovedDocuments().Any() ||
+                    pc.GetRemovedMetadataReferences().Any() ||
+                    pc.GetRemovedProjectReferences().Any())
+                {
+                    projectsToLoad.Add(GetHostProject(pc.ProjectId).Guid);
+                }
+            }
+
+            if (projectsToLoad.Any())
+            {
+                var vsSolution4 = GetVsService(typeof(SVsSolution)) as IVsSolution4;
+                vsSolution4.EnsureProjectsAreLoaded(
+                    (uint)projectsToLoad.Count,
+                    projectsToLoad.ToArray(),
+                    (uint)__VSBSLFLAGS.VSBSLFLAGS_None);
+            }
+
             // first make sure we can edit the document we will be updating (check them out from source control, etc)
-            var changedDocs = newSolution.GetChanges(this.CurrentSolution).GetProjectChanges().SelectMany(pd => pd.GetChangedDocuments()).ToList();
+            var changedDocs = projectChanges.SelectMany(pd => pd.GetChangedDocuments()).ToList();
             if (changedDocs.Count > 0)
             {
                 this.EnsureEditableDocuments(changedDocs);

src/VisualStudio/Core/Def/ServicesVisualStudio.csproj

@@ -90,6 +90,7 @@
     <Compile Include="Implementation\Preview\ReferenceChange.ProjectReferenceChange.cs" />
     <Compile Include="Implementation\Preview\ReferenceChange.cs" />
     <Compile Include="Implementation\ProjectSystem\CPS\ICodeModelFactory.cs" />
+    <Compile Include="Implementation\ProjectSystem\IDeferredProjectWorkspaceService.cs" />
     <Compile Include="Implementation\ProjectSystem\Legacy\AbstractLegacyProject_ICompilerOptionsHostObject.cs" />
     <Compile Include="Implementation\ProjectSystem\Legacy\AbstractLegacyProject_IIntellisenseBuildTarget.cs" />
     <Compile Include="Implementation\ProjectSystem\CPS\IWorkspaceProjectContextFactory.cs" />

src/VisualStudio/Core/Impl/CodeModel/AbstractProjectCodeModel.cs

@@ -66,7 +66,7 @@ internal CodeModelProjectCache GetCodeModelCache()
 
         public bool TryGetCachedFileCodeModel(string fileName, out ComHandle<EnvDTE80.FileCodeModel2, FileCodeModel> fileCodeModelHandle)
         {
-            var handle = GetCodeModelCache().GetComHandleForFileCodeModel(fileName);
+            var handle = GetCodeModelCache()?.GetComHandleForFileCodeModel(fileName);
 
             fileCodeModelHandle = handle != null
                 ? handle.Value

src/VisualStudio/Core/Impl/ProjectSystem/CPS/CPSProject.cs

@@ -43,13 +43,22 @@ internal sealed partial class CPSProject : AbstractProject
         // We might we invoked from a background thread, so schedule the disconnect on foreground task scheduler.
         public sealed override void Disconnect()
         {
-            InvokeBelowInputPriority(() =>
+            if (IsForeground())
             {
-                // clear code model cache and shutdown instances, if any exists.
-                _projectCodeModel?.OnProjectClosed();
+                DisconnectCore();
+            }
+            else
+            {
+                InvokeBelowInputPriority(DisconnectCore);
+            }
+        }
+
+        private void DisconnectCore()
+        {
+            // clear code model cache and shutdown instances, if any exists.
+            _projectCodeModel?.OnProjectClosed();
 
-                base.Disconnect();
-            });
+            base.Disconnect();
         }
     }
 }

src/VisualStudio/Core/Impl/ProjectSystem/CPS/CPSProjectFactory.cs

@@ -59,13 +59,9 @@ internal static CPSProject CreateCPSProject(VisualStudioProjectTracker projectTr
             object hierarchy,
             string binOutputPath)
         {
-            Contract.ThrowIfNull(hierarchy);
+            // NOTE: It is acceptable for hierarchy to be null in Deferred Project Load scenarios.
             var vsHierarchy = hierarchy as IVsHierarchy;
-            if (vsHierarchy == null)
-            {
-                throw new ArgumentException(nameof(hierarchy));
-            }
-            
+
             Func<ProjectId, IVsReportExternalErrors> getExternalErrorReporter = id => GetExternalErrorReporter(id, languageName);
             return new CPSProject(_visualStudioWorkspace.ProjectTracker, getExternalErrorReporter, projectDisplayName, projectFilePath,
                 vsHierarchy, languageName, projectGuid, binOutputPath, _serviceProvider, _visualStudioWorkspace, _hostDiagnosticUpdateSource,

src/VisualStudio/Core/Impl/ProjectSystem/CPS/CPSProject_IWorkspaceProjectContext.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.VisualStudio.LanguageServices.ProjectSystem;
 using Roslyn.Utilities;
@@ -108,29 +109,14 @@ public new void RemoveMetadataReference(string referencePath)
         public void AddProjectReference(IWorkspaceProjectContext project, MetadataReferenceProperties properties)
         {
             var abstractProject = GetAbstractProject(project);
-
-            // AbstractProject and ProjectTracker track project references using the project bin output path.
-            // Setting the command line arguments should have already set the output file name and folder.
-            // We fetch this output path to add the reference.
-            var referencedProject = this.ProjectTracker.GetProject(abstractProject.Id);
-            var binPathOpt = referencedProject.BinOutputPath;
-            if (!string.IsNullOrEmpty(binPathOpt))
-            {
-                AddMetadataReferenceAndTryConvertingToProjectReferenceIfPossible(binPathOpt, properties);
-            }
+            AddProjectReference(new ProjectReference(abstractProject.Id, properties.Aliases, properties.EmbedInteropTypes));
         }
 
         public void RemoveProjectReference(IWorkspaceProjectContext project)
         {
             var referencedProject = GetAbstractProject(project);
-
-            // AbstractProject and ProjectTracker track project references using the project bin output path.
-            // We fetch this output path to remove the reference.
-            var binPathOpt = referencedProject.BinOutputPath;
-            if (!string.IsNullOrEmpty(binPathOpt))
-            {
-                base.RemoveMetadataReference(binPathOpt);
-            }
+            var projectReference = GetCurrentProjectReferences().Single(p => p.ProjectId == referencedProject.Id);
+            RemoveProjectReference(projectReference);
         }
 
         private AbstractProject GetAbstractProject(IWorkspaceProjectContext project)
@@ -148,7 +134,7 @@ private AbstractProject GetAbstractProject(IWorkspaceProjectContext project)
         #region Files
         public void AddSourceFile(string filePath, bool isInCurrentContext = true, IEnumerable<string> folderNames = null, SourceCodeKind sourceCodeKind = SourceCodeKind.Regular)
         {
-            AddFile(filePath, sourceCodeKind, getIsCurrentContext: _ => isInCurrentContext, folderNames: folderNames.ToImmutableArrayOrEmpty());
+            AddFile(filePath, sourceCodeKind, _ => isInCurrentContext, _ => folderNames.ToImmutableArrayOrEmpty());
         }
 
         public void RemoveSourceFile(string filePath)

src/VisualStudio/Core/Next/ProjectSystem/DeferredProjectWorkspaceService.cs

+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Composition;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
+using Microsoft.VisualStudio.Shell;
+using Microsoft.VisualStudio.Shell.Interop;
+using Microsoft.VisualStudio.Workspace.Extensions;
+using Microsoft.VisualStudio.Workspace.VSIntegration;
+using Roslyn.Utilities;
+
+namespace Microsoft.VisualStudio.LanguageServices.ProjectSystem
+{
+    [ExportWorkspaceService(typeof(IDeferredProjectWorkspaceService)), Shared]
+    internal class DeferredProjectWorkspaceService : IDeferredProjectWorkspaceService
+    {
+        private readonly IVsSolutionWorkspaceService _solutionWorkspaceService;
+        private readonly IVsSolution7 _solution7;
+
+        [ImportingConstructor]
+        public DeferredProjectWorkspaceService(SVsServiceProvider serviceProvider)
+        {
+            _solutionWorkspaceService = serviceProvider.GetService(typeof(SVsSolutionWorkspaceService)) as IVsSolutionWorkspaceService;
+            _solution7 = serviceProvider.GetService(typeof(SVsSolution)) as IVsSolution7;
+        }
+
+        public bool IsDeferredProjectLoadEnabled => _solution7?.IsSolutionLoadDeferred() == true;
+
+        public async Task<IReadOnlyDictionary<string, DeferredProjectInformation>> GetDeferredProjectInfoForConfigurationAsync(
+            string solutionConfiguration,
+            CancellationToken cancellationToken)
+        {
+            var commandLineInfos = await _solutionWorkspaceService.GetManagedCommandLineInfoAsync(
+                solutionConfiguration, cancellationToken).ConfigureAwait(false);
+
+            // NOTE: Anycode gives us the project references as if they were command line arguments with
+            // "/ProjectReference:" prepended.  Strip that off here.
+            var result = ImmutableDictionary.CreateRange(
+                commandLineInfos.Select(kvp => KeyValuePair.Create(
+                    kvp.Key,
+                    new DeferredProjectInformation(
+                        kvp.Value.TargetPath,
+                        kvp.Value.CommandLineArgs,
+                        kvp.Value.ProjectReferences.Select(p => p.Substring("/ProjectReference:".Length)).ToImmutableArray()))));
+            return result;
+        }
+    }
+}

src/VisualStudio/Core/Next/Remote/RemoteHostClientFactory.cs

@@ -9,6 +9,8 @@
 
 namespace Microsoft.VisualStudio.LanguageServices.Remote
 {
+    using Workspace = Microsoft.CodeAnalysis.Workspace;
+
     [ExportWorkspaceService(typeof(IRemoteHostClientFactory)), Shared]
     internal class RemoteHostClientFactory : IRemoteHostClientFactory
     {
@@ -28,4 +30,4 @@ public Task<RemoteHostClient> CreateAsync(Workspace workspace, CancellationToken
             }
         }
     }
-}
+}
\ No newline at end of file

src/VisualStudio/Core/Next/Remote/ServiceHubRemoteHostClient.cs

@@ -15,6 +15,8 @@
 
 namespace Microsoft.VisualStudio.LanguageServices.Remote
 {
+    using Workspace = Microsoft.CodeAnalysis.Workspace;
+
     internal partial class ServiceHubRemoteHostClient : RemoteHostClient
     {
         private readonly HubClient _hubClient;

src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj

@@ -106,6 +106,7 @@
     <Compile Include="FindReferences\StreamingFindReferencesPresenter.TableDataSourceFindReferencesContext.cs" />
     <Compile Include="FindReferences\StreamingFindReferencesPresenter.TableEntriesSnapshot.cs" />
     <Compile Include="FindReferences\TaggedTextAndHighlightSpan.cs" />
+    <Compile Include="ProjectSystem\DeferredProjectWorkspaceService.cs" />
     <Compile Include="Remote\JsonRpcClient.cs" />
     <Compile Include="Remote\JsonRpcSession.cs" />
     <Compile Include="Remote\RemoteHostClientFactory.cs" />
@@ -130,4 +131,4 @@
     <InternalsVisibleToTest Include="Roslyn.VisualStudio.Next.UnitTests" />
   </ItemGroup>
   <Import Project="..\..\..\..\build\Targets\VSL.Imports.targets" />
-</Project>
+</Project>
\ No newline at end of file

src/VisualStudio/Core/Next/project.json

@@ -12,9 +12,11 @@
         },
         "Microsoft.ServiceHub.Client": "1.0.103-rc",
         "Newtonsoft.Json": "8.0.3",
+        "RoslynDependencies.Microsoft.VisualStudio.Shell.Interop.15.0.DesignTime": "15.0.25718-Preview5",
+        "RoslynDependencies.Microsoft.VisualStudio.Workspace": "14.0.983-pre-ge167e81694",
         "System.Collections.Immutable": "1.2.0"
     },
     "frameworks": {
         "net46": { }
     }
-}
+}
\ No newline at end of file

src/VisualStudio/Core/Test/ProjectSystemShim/Framework/TestEnvironment.vb

@@ -38,8 +38,9 @@ Namespace Microsoft.VisualStudio.LanguageServices.UnitTests.ProjectSystemShim.Fr
 
             _monitorSelectionMock = New MockShellMonitorSelection(solutionIsFullyLoaded)
             _serviceProvider = New MockServiceProvider(_monitorSelectionMock)
-            _projectTracker = New VisualStudioProjectTracker(_serviceProvider)
             _workspace = New TestWorkspace()
+            _projectTracker = New VisualStudioProjectTracker(_serviceProvider, _workspace.Services)
+
             Dim metadataReferenceProvider = New VisualStudioMetadataReferenceManager(_serviceProvider, _workspace.Services.GetService(Of ITemporaryStorageService)())
             Dim ruleSetFileProvider = New VisualStudioRuleSetManager(
                 DirectCast(_serviceProvider.GetService(GetType(SVsFileChangeEx)), IVsFileChangeEx),

src/VisualStudio/Next/CodeLens/RemoteCodeLensReferencesService.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.Collections.Generic;
-using System.Composition;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CodeLens;
-using Microsoft.CodeAnalysis.Host.Mef;
-using Microsoft.CodeAnalysis.Remote;
-using Microsoft.CodeAnalysis.Remote.Diagnostics;
-using Microsoft.VisualStudio.LanguageServices.Implementation.Extensions;
-using Microsoft.VisualStudio.LanguageServices.Remote;
-
-namespace Microsoft.VisualStudio.LanguageServices.CodeLens
-{
-    [ExportWorkspaceService(typeof(ICodeLensReferencesService), layer: ServiceLayer.Host), Shared]
-    internal sealed class RemoteCodeLensReferencesService : ICodeLensReferencesService
-    {
-        public async Task<ReferenceCount> GetReferenceCountAsync(Solution solution, DocumentId documentId, SyntaxNode syntaxNode, int maxSearchResults,
-            CancellationToken cancellationToken)
-        {
-            var remoteHostClient = await solution.Workspace.Services.GetService<IRemoteHostClientService>().GetRemoteHostClientAsync(cancellationToken).ConfigureAwait(false);
-            if (remoteHostClient == null)
-            {
-                // remote host is not running. this can happen if remote host is disabled.
-                return await CodeLensReferencesServiceFactory.Instance.GetReferenceCountAsync(solution, documentId, syntaxNode, maxSearchResults, cancellationToken).ConfigureAwait(false);
-            }
-
-            // TODO: send telemetry on session
-            using (var session = await remoteHostClient.CreateCodeAnalysisServiceSessionAsync(solution, cancellationToken).ConfigureAwait(false))
-            {
-                return await session.InvokeAsync<ReferenceCount>(WellKnownServiceHubServices.CodeAnalysisService_GetReferenceCountAsync, new CodeLensArguments(documentId, syntaxNode), maxSearchResults).ConfigureAwait(false);
-            }
-        }
-
-        public async Task<IEnumerable<ReferenceLocationDescriptor>> FindReferenceLocationsAsync(Solution solution, DocumentId documentId, SyntaxNode syntaxNode,
-            CancellationToken cancellationToken)
-        {
-            var remoteHostClient = await solution.Workspace.Services.GetService<IRemoteHostClientService>().GetRemoteHostClientAsync(cancellationToken).ConfigureAwait(false);
-            if (remoteHostClient == null)
-            {
-                // remote host is not running. this can happen if remote host is disabled.
-                return await CodeLensReferencesServiceFactory.Instance.FindReferenceLocationsAsync(solution, documentId, syntaxNode, cancellationToken).ConfigureAwait(false);
-            }
-
-            // TODO: send telemetry on session
-            using (var session = await remoteHostClient.CreateCodeAnalysisServiceSessionAsync(solution, cancellationToken).ConfigureAwait(false))
-            {
-                return await session.InvokeAsync<IEnumerable<ReferenceLocationDescriptor>>(WellKnownServiceHubServices.CodeAnalysisService_FindReferenceLocationsAsync, new CodeLensArguments(documentId, syntaxNode)).ConfigureAwait(false);
-            }
-        }
-
-        public async Task<IEnumerable<ReferenceMethodDescriptor>> FindReferenceMethodsAsync(Solution solution, DocumentId documentId, SyntaxNode syntaxNode,
-            CancellationToken cancellationToken)
-        {
-            var remoteHostClient = await solution.Workspace.Services.GetService<IRemoteHostClientService>().GetRemoteHostClientAsync(cancellationToken).ConfigureAwait(false);
-            if (remoteHostClient == null)
-            {
-                // remote host is not running. this can happen if remote host is disabled.
-                return await CodeLensReferencesServiceFactory.Instance.FindReferenceMethodsAsync(solution, documentId, syntaxNode, cancellationToken).ConfigureAwait(false);
-            }
-
-            // TODO: send telemetry on session
-            using (var session = await remoteHostClient.CreateCodeAnalysisServiceSessionAsync(solution, cancellationToken).ConfigureAwait(false))
-            {
-                return await session.InvokeAsync<IEnumerable<ReferenceMethodDescriptor>>(WellKnownServiceHubServices.CodeAnalysisService_FindReferenceMethodsAsync, new CodeLensArguments(documentId, syntaxNode)).ConfigureAwait(false);
-            }
-        }
-
-        public async Task<string> GetFullyQualifiedName(Solution solution, DocumentId documentId, SyntaxNode syntaxNode,
-            CancellationToken cancellationToken)
-        {
-            var remoteHostClient = await solution.Workspace.Services.GetService<IRemoteHostClientService>().GetRemoteHostClientAsync(cancellationToken).ConfigureAwait(false);
-            if (remoteHostClient == null)
-            {
-                // remote host is not running. this can happen if remote host is disabled.
-                return await CodeLensReferencesServiceFactory.Instance.GetFullyQualifiedName(solution, documentId, syntaxNode, cancellationToken).ConfigureAwait(false);
-            }
-
-            // TODO: send telemetry on session
-            using (var session = await remoteHostClient.CreateCodeAnalysisServiceSessionAsync(solution, cancellationToken).ConfigureAwait(false))
-            {
-                return await session.InvokeAsync<string>(WellKnownServiceHubServices.CodeAnalysisService_GetFullyQualifiedName, new CodeLensArguments(documentId, syntaxNode)).ConfigureAwait(false);
-            }
-        }
-    }
-}

src/VisualStudio/VisualBasic/Impl/LanguageService/VisualBasicPackage.IVbCompiler.vb

@@ -4,7 +4,9 @@ Imports Microsoft.CodeAnalysis
 Imports Microsoft.CodeAnalysis.Host
 Imports Microsoft.CodeAnalysis.VisualBasic
 Imports Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem
+Imports Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.Legacy
 Imports Microsoft.VisualStudio.LanguageServices.Implementation.TaskList
+Imports Microsoft.VisualStudio.LanguageServices.ProjectSystem
 Imports Microsoft.VisualStudio.LanguageServices.VisualBasic.ProjectSystemShim
 Imports Microsoft.VisualStudio.LanguageServices.VisualBasic.ProjectSystemShim.Interop
 Imports Microsoft.VisualStudio.Shell.Interop
@@ -19,17 +21,19 @@ Namespace Microsoft.VisualStudio.LanguageServices.VisualBasic
         End Function
 
         Public Function CreateProject(wszName As String, punkProject As Object, pProjHier As IVsHierarchy, pVbCompilerHost As IVbCompilerHost) As IVbCompilerProject Implements IVbCompiler.CreateProject
-            Dim visualStudioWorkspace = ComponentModel.GetService(Of VisualStudioWorkspaceImpl)()
             Dim hostDiagnosticUpdateSource = ComponentModel.GetService(Of HostDiagnosticUpdateSource)()
+
+            Workspace.ProjectTracker.TryDisconnectExistingDeferredProject(pProjHier, wszName)
+
             Return New VisualBasicProjectShimWithServices(
-                visualStudioWorkspace.ProjectTracker,
+                Workspace.ProjectTracker,
                 pVbCompilerHost,
                 wszName,
                 pProjHier,
                 Me,
-                visualStudioWorkspace,
+                Workspace,
                 hostDiagnosticUpdateSource,
-                commandLineParserServiceOpt:=visualStudioWorkspace.Services.GetLanguageServices(LanguageNames.VisualBasic).GetService(Of ICommandLineParserService))
+                commandLineParserServiceOpt:=Workspace.Services.GetLanguageServices(LanguageNames.VisualBasic).GetService(Of ICommandLineParserService))
         End Function
 
         Public Function IsValidIdentifier(wszIdentifier As String) As Boolean Implements IVbCompiler.IsValidIdentifier

src/VisualStudio/VisualBasic/Impl/ProjectSystemShim/VisualBasicProject.vb

@@ -104,7 +104,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.VisualBasic.ProjectSystemShim
                 ' We trust the project system to only tell us about files that we can use.
                 Dim canUseTextBuffer As Func(Of ITextBuffer, Boolean) = Function(t) True
 
-                MyBase.AddFile(wszFileName, SourceCodeKind.Regular, itemid)
+                MyBase.AddFile(wszFileName, SourceCodeKind.Regular)
             Catch e As Exception When FilterException(e)
                 Throw ExceptionUtilities.Unreachable
             End Try

src/VisualStudio/Xaml/Impl/Implementation/XamlTextViewCreationListener.cs

@@ -16,6 +16,7 @@
 using Microsoft.VisualStudio.Text.Editor;
 using Microsoft.VisualStudio.TextManager.Interop;
 using Microsoft.VisualStudio.Utilities;
+using Roslyn.Utilities;
 
 namespace Microsoft.VisualStudio.LanguageServices.Xaml
 {
@@ -142,7 +143,9 @@ private AbstractProject GetXamlProject(IVsHierarchy hierarchy)
         private bool TryCreateXamlDocument(AbstractProject project, string filePath, out IVisualStudioHostDocument vsDocument)
         {
             vsDocument = _vsWorkspace.ProjectTracker.DocumentProvider.TryGetDocumentForFile(
-                project, ImmutableArray<string>.Empty, filePath, SourceCodeKind.Regular, tb => tb.ContentType.IsOfType(ContentTypeNames.XamlContentType));
+                project, filePath, SourceCodeKind.Regular,
+                tb => tb.ContentType.IsOfType(ContentTypeNames.XamlContentType),
+                _ => SpecializedCollections.EmptyReadOnlyList<string>());
 
             return vsDocument != null;
         }

src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs

@@ -14,6 +14,21 @@ namespace Roslyn.Utilities
     [SuppressMessage("ApiDesign", "CA1068", Justification = "Matching TPL Signatures")]
     internal static partial class TaskExtensions
     {
+        /// <summary>
+        /// Use to explicitly indicate that you are not waiting for a task to complete
+        /// Observes the exceptions from it.
+        /// </summary>
+        public static async void FireAndForget(this Task task)
+        {
+            try
+            {
+                await task.ConfigureAwait(false);
+            }
+            catch (OperationCanceledException)
+            {
+            }
+        }
+
         public static T WaitAndGetResult<T>(this Task<T> task, CancellationToken cancellationToken)
         {
 #if DEBUG

src/Workspaces/Remote/Core/Services/RoslynServices.cs

@@ -26,4 +26,4 @@ internal static class RoslynServices
         public static readonly SolutionService SolutionService = new SolutionService();
         public static readonly CompilationService CompilationService = new CompilationService();
     }
-}
+}
\ No newline at end of file