Make more tests async.

src/EditorFeatures/VisualBasicTest/Diagnostics/GenerateConstructor/GenerateConstructorTests.vb

@@ -504,8 +504,8 @@ NewLines("Imports System.Linq \n Class C \n Private v As Integer \n Sub New() \n
 
         <WorkItem(6541, "https://github.com/dotnet/Roslyn/issues/6541")>
         <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)>
-        Public Sub TestGenerateInDerivedType1()
-            Test(
+        Public Async Function TestGenerateInDerivedType1() As Task
+            Await TestAsync(
 "
 Public Class Base
     Public Sub New(a As String)
@@ -531,12 +531,12 @@ Public Class Derived
         MyBase.New(a)
     End Sub
 End Class")
-        End Sub
+        End Function
 
         <WorkItem(6541, "https://github.com/dotnet/Roslyn/issues/6541")>
         <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsGenerateConstructor)>
-        Public Sub TestGenerateInDerivedType2()
-            Test(
+        Public Async Function TestGenerateInDerivedType2() As Task
+            Await TestAsync(
 "
 Public Class Base
     Public Sub New(a As Integer, Optional b As String = Nothing)
@@ -562,6 +562,6 @@ Public Class Derived
         MyBase.New(a, b)
     End Sub
 End Class")
-        End Sub
+        End Function
     End Class
 End Namespace

src/Workspaces/CSharp/Portable/Rename/CSharpRenameRewriterLanguageService.cs

@@ -218,7 +218,7 @@ public override SyntaxToken VisitToken(SyntaxToken token)
 
                 if (tokenNeedsConflictCheck)
                 {
-                    newToken = RenameAndAnnotateAsync(token, newToken, isRenameLocation, isOldText).WaitAndGetResult(_cancellationToken);
+                    newToken = RenameAndAnnotateAsync(token, newToken, isRenameLocation, isOldText).WaitAndGetResult_CanCallOnBackground(_cancellationToken);
 
                     if (!_isProcessingComplexifiedSpans)
                     {
@@ -382,9 +382,8 @@ private async Task<SyntaxToken> RenameAndAnnotateAsync(SyntaxToken token, Syntax
                         AddModifiedSpan(oldSpan, newToken.Span);
                     }
 
-                    RenameDeclarationLocationReference[] renameDeclarationLocations =
-                        ConflictResolver.CreateDeclarationLocationAnnotationsAsync(_solution, symbols, _cancellationToken)
-                                .WaitAndGetResult(_cancellationToken);
+                    var renameDeclarationLocations = await
+                        ConflictResolver.CreateDeclarationLocationAnnotationsAsync(_solution, symbols, _cancellationToken).ConfigureAwait(false);
 
                     var isNamespaceDeclarationReference = false;
                     if (isRenameLocation && token.GetPreviousToken().IsKind(SyntaxKind.NamespaceKeyword))

src/Workspaces/Core/Portable/Rename/ConflictEngine/ConflictResolution.cs

@@ -6,6 +6,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.LanguageServices;
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
@@ -59,14 +60,14 @@ internal void UpdateCurrentSolution(Solution solution)
             _newSolution = solution;
         }
 
-        internal void RemoveAllRenameAnnotations(IEnumerable<DocumentId> documentWithRenameAnnotations, AnnotationTable<RenameAnnotation> annotationSet, CancellationToken cancellationToken)
+        internal async Task RemoveAllRenameAnnotationsAsync(IEnumerable<DocumentId> documentWithRenameAnnotations, AnnotationTable<RenameAnnotation> annotationSet, CancellationToken cancellationToken)
         {
             foreach (var documentId in documentWithRenameAnnotations)
             {
                 if (_renamedSpansTracker.IsDocumentChanged(documentId))
                 {
                     var document = _newSolution.GetDocument(documentId);
-                    var root = document.GetSyntaxRootAsync(cancellationToken).WaitAndGetResult(cancellationToken);
+                    var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
 
                     // For the computeReplacementToken and computeReplacementNode functions, use 
                     // the "updated" node to maintain any annotation removals from descendants.

src/Workspaces/Core/Portable/Rename/ConflictEngine/ConflictResolver.Session.cs

@@ -199,7 +199,7 @@ public async Task<ConflictResolution> ResolveConflictsAsync()
 
                             // Step 3: Simplify the project
                             conflictResolution.UpdateCurrentSolution(await renamedSpansTracker.SimplifyAsync(conflictResolution.NewSolution, documentsByProject, _replacementTextValid, _renameAnnotations, _cancellationToken).ConfigureAwait(false));
-                            conflictResolution.RemoveAllRenameAnnotations(documentsByProject, _renameAnnotations, _cancellationToken);
+                            await conflictResolution.RemoveAllRenameAnnotationsAsync(documentsByProject, _renameAnnotations, _cancellationToken).ConfigureAwait(false);
                         }
                     }