Merge master to master-vs-deps

src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs

@@ -5537,7 +5537,7 @@ private Conversion GenerateConversionForConditionalOperator(BoundExpression sour
         private static Conversion GenerateConversion(Conversions conversions, BoundExpression sourceExpression, TypeSymbol sourceType, TypeSymbol destinationType, bool fromExplicitCast, bool extensionMethodThisArgument)
         {
             HashSet<DiagnosticInfo> useSiteDiagnostics = null;
-            bool useExpression = UseExpressionForConversion(sourceExpression);
+            bool useExpression = sourceType is null || UseExpressionForConversion(sourceExpression);
             if (extensionMethodThisArgument)
             {
                 return conversions.ClassifyImplicitExtensionMethodThisArgConversion(

src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs

@@ -128501,5 +128501,36 @@ internal interface IB : IA { }
             var comp = CreateCompilation(source);
             comp.VerifyEmitDiagnostics();
         }
+
+        [Fact]
+        [WorkItem(45862, "https://github.com/dotnet/roslyn/issues/45862")]
+        public void Issue_45862()
+        {
+            var source =
+@"#nullable enable
+
+class C
+{
+    void M()
+    {
+        _ = 0 switch
+        {
+            0 =
+            _ = null,
+        };
+    }
+}";
+            var comp = CreateCompilation(source);
+            comp.VerifyEmitDiagnostics(
+                // (9,15): error CS1003: Syntax error, '=>' expected
+                //             0 =
+                Diagnostic(ErrorCode.ERR_SyntaxError, "=").WithArguments("=>", "=").WithLocation(9, 15),
+                // (9,15): error CS1525: Invalid expression term '='
+                //             0 =
+                Diagnostic(ErrorCode.ERR_InvalidExprTerm, "=").WithArguments("=").WithLocation(9, 15),
+                // (10,13): error CS8183: Cannot infer the type of implicitly-typed discard.
+                //             _ = null,
+                Diagnostic(ErrorCode.ERR_DiscardTypeInferenceFailed, "_").WithLocation(10, 13));
+        }
     }
 }

src/VisualStudio/Core/Def/Implementation/Experimentation/KeybindingResetDetector.cs

@@ -114,7 +114,7 @@ private void InitializeCore()
                 return;
             }
 
-            var vsShell = _serviceProvider.GetService<IVsShell, SVsShell>();
+            var vsShell = _serviceProvider.GetService<SVsShell, IVsShell>();
             var hr = vsShell.IsPackageInstalled(ReSharperPackageGuid, out var extensionEnabled);
             if (ErrorHandler.Failed(hr))
             {
@@ -127,7 +127,7 @@ private void InitializeCore()
             if (_resharperExtensionInstalledAndEnabled)
             {
                 // We need to monitor for suspend/resume commands, so create and install the command target and the modal callback.
-                var priorityCommandTargetRegistrar = _serviceProvider.GetService<IVsRegisterPriorityCommandTarget, SVsRegisterPriorityCommandTarget>();
+                var priorityCommandTargetRegistrar = _serviceProvider.GetService<SVsRegisterPriorityCommandTarget, IVsRegisterPriorityCommandTarget>();
                 hr = priorityCommandTargetRegistrar.RegisterPriorityCommandTarget(
                     dwReserved: 0 /* from docs must be 0 */,
                     pCmdTrgt: this,
@@ -335,7 +335,7 @@ async Task EnsureOleCommandTargetAsync()
 
                 await ThreadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
 
-                _oleCommandTarget = _serviceProvider.GetService<IOleCommandTarget, SUIHostCommandDispatcher>();
+                _oleCommandTarget = _serviceProvider.GetService<SUIHostCommandDispatcher, IOleCommandTarget>();
             }
         }
 
@@ -345,7 +345,7 @@ private void RestoreVsKeybindings()
 
             if (_uiShell == null)
             {
-                _uiShell = _serviceProvider.GetService<IVsUIShell, SVsUIShell>();
+                _uiShell = _serviceProvider.GetService<SVsUIShell, IVsUIShell>();
             }
 
             ErrorHandler.ThrowOnFailure(_uiShell.PostExecCommand(
@@ -432,7 +432,7 @@ private async Task ShutdownAsync()
 
             if (_priorityCommandTargetCookie != VSConstants.VSCOOKIE_NIL)
             {
-                var priorityCommandTargetRegistrar = _serviceProvider.GetService<IVsRegisterPriorityCommandTarget, SVsRegisterPriorityCommandTarget>();
+                var priorityCommandTargetRegistrar = _serviceProvider.GetService<SVsRegisterPriorityCommandTarget, IVsRegisterPriorityCommandTarget>();
                 var cookie = _priorityCommandTargetCookie;
                 _priorityCommandTargetCookie = VSConstants.VSCOOKIE_NIL;
                 var hr = priorityCommandTargetRegistrar.UnregisterPriorityCommandTarget(cookie);

src/VisualStudio/Core/Def/Implementation/Library/ClassView/AbstractSyncClassViewCommandHandler.cs

@@ -9,7 +9,7 @@
 using Microsoft.CodeAnalysis.LanguageServices;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.VisualStudio.Commanding;
-using Microsoft.VisualStudio.LanguageServices.Implementation.Extensions;
+using Microsoft.VisualStudio.LanguageServices.Utilities;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Shell.Interop;
 using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;

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

@@ -1033,7 +1033,7 @@ private bool TryGetFrame(CodeAnalysis.TextDocument document, [NotNullWhen(return
                 // document using its ItemId. Thus, we must use OpenDocumentViaProject, which only
                 // depends on the file path.
 
-                var openDocumentService = ServiceProvider.GlobalProvider.GetService<IVsUIShellOpenDocument, SVsUIShellOpenDocument>();
+                var openDocumentService = ServiceProvider.GlobalProvider.GetService<SVsUIShellOpenDocument, IVsUIShellOpenDocument>();
                 return ErrorHandler.Succeeded(openDocumentService.OpenDocumentViaProject(
                     document.FilePath,
                     VSConstants.LOGVIEWID.TextView_guid,
@@ -1072,7 +1072,7 @@ public void CloseDocumentCore(DocumentId documentId)
                 var filePath = this.GetFilePath(documentId);
                 if (filePath != null)
                 {
-                    var openDocumentService = ServiceProvider.GlobalProvider.GetService<IVsUIShellOpenDocument, SVsUIShellOpenDocument>();
+                    var openDocumentService = ServiceProvider.GlobalProvider.GetService<SVsUIShellOpenDocument, IVsUIShellOpenDocument>();
                     if (ErrorHandler.Succeeded(openDocumentService.IsDocumentOpen(null, 0, filePath, Guid.Empty, 0, out var uiHierarchy, null, out var frame, out var isOpen)))
                     {
                         // TODO: do we need save argument for CloseDocument?

src/VisualStudio/Core/Def/Implementation/Workspace/VisualStudioSymbolNavigationService.cs

@@ -24,9 +24,9 @@
 using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.ComponentModelHost;
 using Microsoft.VisualStudio.Editor;
-using Microsoft.VisualStudio.LanguageServices.Implementation.Extensions;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Library;
 using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
+using Microsoft.VisualStudio.LanguageServices.Utilities;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Shell.Interop;
 using Microsoft.VisualStudio.Text;

src/VisualStudio/Core/Def/Microsoft.VisualStudio.LanguageServices.csproj

@@ -34,6 +34,7 @@
                                Class="Microsoft.VisualStudio.LanguageServices.Setup.RoslynPackage"
                                AllowsBackgroundLoad="true"/>
     <None Include="PackageRegistration.pkgdef" PkgDefEntry="FileContent" />
+    <None Include=".\ColorSchemes\VisualStudio2019.pkgdef" PkgDefEntry="FileContent" />
   </ItemGroup>
   <ItemGroup Label="Build Items">
     <Compile Include="..\..\..\Compilers\Shared\GlobalAssemblyCacheHelpers\GlobalAssemblyCacheLocation.cs">

src/VisualStudio/Core/Def/Utilities/IServiceProviderExtensions.cs

@@ -3,19 +3,18 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Diagnostics;
 
 namespace Microsoft.VisualStudio.LanguageServices.Utilities
 {
     internal static class IServiceProviderExtensions
     {
-        /// <summary>
-        /// Returns the specified interface from the service. This is useful when the service and interface differ
-        /// </summary>
-        public static TInterfaceType GetService<TInterfaceType, TServiceType>(this IServiceProvider sp)
-            where TInterfaceType : class
-            where TServiceType : class
+        /// <inheritdoc cref="Shell.ServiceExtensions.GetService{TService, TInterface}(IServiceProvider, bool)"/>
+        public static TInterface GetService<TService, TInterface>(this IServiceProvider sp)
         {
-            return (TInterfaceType)sp.GetService(typeof(TServiceType));
+            var service = (TInterface)sp.GetService(typeof(TService));
+            Debug.Assert(service != null);
+            return service;
         }
 
         /// <summary>