Use compound assignment

src/EditorFeatures/TestUtilities/Workspaces/TestWorkspace_XmlConsumption.cs

@@ -85,7 +85,7 @@ public static TestWorkspace Create(string xmlDefinition, bool completed = true,
                 throw new ArgumentException();
             }
 
-            exportProvider = exportProvider ?? TestExportProvider.ExportProviderWithCSharpAndVisualBasic;
+            exportProvider ??= TestExportProvider.ExportProviderWithCSharpAndVisualBasic;
 
             var workspace = new TestWorkspace(exportProvider, workspaceKind);
 

src/VisualStudio/CSharp/Test/Interactive/Commands/ResetInteractiveTests.cs

@@ -63,8 +63,8 @@ public async Task TestResetREPLWithProjectContext()
             List<string> expectedReferences = null,
             List<string> expectedUsings = null)
         {
-            expectedReferences = expectedReferences ?? new List<string>();
-            expectedUsings = expectedUsings ?? new List<string>();
+            expectedReferences ??= new List<string>();
+            expectedUsings ??= new List<string>();
 
             var testHost = new InteractiveWindowTestHost(workspace.ExportProvider);
             var executedSubmissionCalls = new List<string>();

src/VisualStudio/Core/Def/Implementation/Remote/RemoteHostClientServiceFactory.SolutionChecksumUpdater.cs

@@ -111,7 +111,7 @@ private void EnqueueChecksumUpdate()
 
                 lock (_gate)
                 {
-                    _lastToken = _lastToken ?? Listener.BeginAsyncOperation(nameof(SolutionChecksumUpdater));
+                    _lastToken ??= Listener.BeginAsyncOperation(nameof(SolutionChecksumUpdater));
                 }
 
                 _event.Release();

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

@@ -592,7 +592,7 @@ protected EnvDTE.vsCMElement GetElementKind(ITypeSymbol typeSymbol)
             {
                 if (location.IsInSource)
                 {
-                    compilation = compilation ?? project.GetCompilationAsync(CancellationToken.None).WaitAndGetResult_CodeModel(CancellationToken.None);
+                    compilation ??= project.GetCompilationAsync(CancellationToken.None).WaitAndGetResult_CodeModel(CancellationToken.None);
 
                     if (compilation.ContainsSyntaxTree(location.SourceTree))
                     {
@@ -606,7 +606,7 @@ protected EnvDTE.vsCMElement GetElementKind(ITypeSymbol typeSymbol)
                         }
                         else
                         {
-                            generatedCode = generatedCode ?? Tuple.Create(document.Id, location);
+                            generatedCode ??= Tuple.Create(document.Id, location);
                         }
                     }
                 }

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

@@ -673,7 +673,7 @@ int IVBFileCodeModelEvents.EndEdit()
                             var node = element.LookupNode();
                             if (node != null)
                             {
-                                elementAndPaths = elementAndPaths ?? new List<ValueTuple<AbstractKeyedCodeElement, SyntaxPath>>();
+                                elementAndPaths ??= new List<ValueTuple<AbstractKeyedCodeElement, SyntaxPath>>();
                                 elementAndPaths.Add(ValueTuple.Create(element, new SyntaxPath(node)));
                             }
                         }

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

@@ -313,7 +313,7 @@ private async Task<Project> UpdateProjectInfoAsync(Project project, Checksum inf
                 {
                     if (!oldMap.ContainsKey(kv.Key))
                     {
-                        documentsToAdd = documentsToAdd ?? ImmutableArray.CreateBuilder<DocumentInfo>();
+                        documentsToAdd ??= ImmutableArray.CreateBuilder<DocumentInfo>();
 
                         // we have new document added
                         var documentInfo = await SolutionInfoCreator.CreateDocumentInfoAsync(_assetService, kv.Value.Checksum, _cancellationToken).ConfigureAwait(false);