Pass along cancellation token where appropriate instead of using CancellationToken.None

src/Features/CSharp/Portable/CodeRefactorings/InlineTemporary/InlineTemporaryCodeRefactoringProvider.cs

@@ -460,7 +460,7 @@ private ExpressionSyntax SkipRedundantExteriorParentheses(ExpressionSyntax expre
             var newVariableDeclarator = await FindDeclaratorAsync(updatedDocument, cancellationToken).ConfigureAwait(false);
             localSymbol = (ILocalSymbol)semanticModel.GetDeclaredSymbol(newVariableDeclarator, cancellationToken);
 
-            var explicitCastExpression = newExpression.CastIfPossible(localSymbol.Type, newVariableDeclarator.SpanStart, semanticModel);
+            var explicitCastExpression = newExpression.CastIfPossible(localSymbol.Type, newVariableDeclarator.SpanStart, semanticModel, cancellationToken);
             if (explicitCastExpression != newExpression)
             {
                 updatedDocument = await updatedDocument.ReplaceNodeAsync(newExpression, explicitCastExpression, cancellationToken).ConfigureAwait(false);

src/Features/VisualBasic/Portable/CodeRefactorings/InlineTemporary/InlineTemporaryCodeRefactoringProvider.vb

@@ -412,7 +412,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.CodeRefactorings.InlineTemporary
             explicitInitializer = explicitInitializer.CastIfPossible(local.Type,
                                                                      modifiedIdentifier.SpanStart,
                                                                      semanticModel,
-                                                                     wasCastAdded)
+                                                                     wasCastAdded,
+                                                                     cancellationToken)
 
             Return explicitInitializer.WithAdditionalAnnotations(s_expressionToInlineAnnotation)
         End Function

src/Workspaces/CSharp/Portable/Extensions/ExpressionSyntaxExtensions.cs

@@ -97,7 +97,8 @@ public static ExpressionSyntax WalkDownParentheses(this ExpressionSyntax express
             this ExpressionSyntax expression,
             ITypeSymbol targetType,
             int position,
-            SemanticModel semanticModel)
+            SemanticModel semanticModel,
+            CancellationToken cancellationToken)
         {
             if (targetType.ContainsAnonymousType())
             {
@@ -123,7 +124,7 @@ public static ExpressionSyntax WalkDownParentheses(this ExpressionSyntax express
             var castExpression = expression.Cast(targetType);
 
             // Ensure that inserting the cast doesn't change the semantics.
-            var specAnalyzer = new SpeculationAnalyzer(expression, castExpression, semanticModel, CancellationToken.None);
+            var specAnalyzer = new SpeculationAnalyzer(expression, castExpression, semanticModel, cancellationToken);
             var speculativeSemanticModel = specAnalyzer.SpeculativeSemanticModel;
             if (speculativeSemanticModel == null)
             {
@@ -131,7 +132,7 @@ public static ExpressionSyntax WalkDownParentheses(this ExpressionSyntax express
             }
 
             var speculatedCastExpression = (CastExpressionSyntax)specAnalyzer.ReplacedExpression;
-            if (!speculatedCastExpression.IsUnnecessaryCast(speculativeSemanticModel, CancellationToken.None))
+            if (!speculatedCastExpression.IsUnnecessaryCast(speculativeSemanticModel, cancellationToken))
             {
                 return expression;
             }
@@ -762,7 +763,7 @@ private static bool CanReplace(ISymbol symbol)
                 return true;
             }
 
-            return TrySimplify(expression, semanticModel, out replacementNode, out issueSpan);
+            return TrySimplify(expression, semanticModel, out replacementNode, out issueSpan, cancellationToken);
         }
 
         private static bool TryReduceExplicitName(
@@ -1933,7 +1934,8 @@ private static bool IsPartOfNamespaceDeclarationName(SyntaxNode node)
             ExpressionSyntax expression,
             SemanticModel semanticModel,
             out ExpressionSyntax replacementNode,
-            out TextSpan issueSpan)
+            out TextSpan issueSpan,
+            CancellationToken cancellationToken)
         {
             replacementNode = null;
             issueSpan = default;
@@ -1955,7 +1957,7 @@ private static bool IsPartOfNamespaceDeclarationName(SyntaxNode node)
                                 .WithAdditionalAnnotations(Simplifier.Annotation);
 
                             // Ensure that replacement doesn't change semantics.
-                            return !ReplacementChangesSemantics(memberAccess, replacementNode, semanticModel);
+                            return !ReplacementChangesSemantics(memberAccess, replacementNode, semanticModel, cancellationToken);
                         }
 
                         return false;
@@ -1971,7 +1973,7 @@ private static bool IsPartOfNamespaceDeclarationName(SyntaxNode node)
                                 .WithAdditionalAnnotations(Simplifier.Annotation);
 
                             // Ensure that replacement doesn't change semantics.
-                            return !ReplacementChangesSemantics(qualifiedName, replacementNode, semanticModel);
+                            return !ReplacementChangesSemantics(qualifiedName, replacementNode, semanticModel, cancellationToken);
                         }
 
                         return false;
@@ -1981,9 +1983,11 @@ private static bool IsPartOfNamespaceDeclarationName(SyntaxNode node)
             return false;
         }
 
-        private static bool ReplacementChangesSemantics(ExpressionSyntax originalExpression, ExpressionSyntax replacedExpression, SemanticModel semanticModel)
+        private static bool ReplacementChangesSemantics(
+            ExpressionSyntax originalExpression, ExpressionSyntax replacedExpression,
+            SemanticModel semanticModel, CancellationToken cancellationToken)
         {
-            var speculationAnalyzer = new SpeculationAnalyzer(originalExpression, replacedExpression, semanticModel, CancellationToken.None);
+            var speculationAnalyzer = new SpeculationAnalyzer(originalExpression, replacedExpression, semanticModel, cancellationToken);
             return speculationAnalyzer.ReplacementChangesSemantics();
         }
 

src/Workspaces/CSharp/Portable/Simplification/CSharpSimplificationService.Expander.cs

@@ -106,7 +106,7 @@ private bool TryCastTo(ITypeSymbol targetType, ExpressionSyntax expression, Expr
                 var speculativeSemanticModel = speculativeAnalyzer.SpeculativeSemanticModel;
                 var speculatedExpression = speculativeAnalyzer.ReplacedExpression;
 
-                var result = speculatedExpression.CastIfPossible(targetType, speculatedExpression.SpanStart, speculativeSemanticModel);
+                var result = speculatedExpression.CastIfPossible(targetType, speculatedExpression.SpanStart, speculativeSemanticModel, _cancellationToken);
 
                 if (result != speculatedExpression)
                 {

src/Workspaces/VisualBasic/Portable/Extensions/ExpressionSyntaxExtensions.vb

@@ -260,8 +260,9 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             targetType As ITypeSymbol,
             position As Integer,
             semanticModel As SemanticModel,
-            <Out> ByRef wasCastAdded As Boolean
-        ) As ExpressionSyntax
+            <Out> ByRef wasCastAdded As Boolean,
+            cancellationToken As CancellationToken) As ExpressionSyntax
+
             wasCastAdded = False
 
             If targetType.ContainsAnonymousType() OrElse expression.IsParentKind(SyntaxKind.AsNewClause) Then
@@ -282,7 +283,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             Dim castExpression = expression.Cast(targetType, isResultPredefinedCast)
 
             ' Ensure that inserting the cast doesn't change the semantics.
-            Dim specAnalyzer = New SpeculationAnalyzer(expression, castExpression, semanticModel, CancellationToken.None)
+            Dim specAnalyzer = New SpeculationAnalyzer(expression, castExpression, semanticModel, cancellationToken)
             Dim speculativeSemanticModel = specAnalyzer.SpeculativeSemanticModel
             If speculativeSemanticModel Is Nothing Then
                 Return expression
@@ -292,7 +293,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             Dim speculatedCastInnerExpression = If(isResultPredefinedCast,
                                                    DirectCast(speculatedCastExpression, PredefinedCastExpressionSyntax).Expression,
                                                    DirectCast(speculatedCastExpression, CastExpressionSyntax).Expression)
-            If Not CastAnalyzer.IsUnnecessary(speculatedCastExpression, speculatedCastInnerExpression, speculativeSemanticModel, True, CancellationToken.None) Then
+            If Not CastAnalyzer.IsUnnecessary(speculatedCastExpression, speculatedCastInnerExpression, speculativeSemanticModel, True, cancellationToken) Then
                 Return expression
             End If
 
@@ -922,7 +923,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
                 Return True
             End If
 
-            Return expression.TrySimplify(semanticModel, replacementNode, issueSpan)
+            Return expression.TrySimplify(semanticModel, replacementNode, issueSpan, cancellationToken)
         End Function
 
         <Extension()>
@@ -1607,9 +1608,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
         Private Function TrySimplify(
             expression As ExpressionSyntax,
             semanticModel As SemanticModel,
-            <Out()> ByRef replacementNode As ExpressionSyntax,
-            <Out()> ByRef issueSpan As TextSpan
-        ) As Boolean
+            <Out> ByRef replacementNode As ExpressionSyntax,
+            <Out> ByRef issueSpan As TextSpan,
+            cancellationToken As CancellationToken) As Boolean
+
             replacementNode = Nothing
             issueSpan = Nothing
 
@@ -1623,7 +1625,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
                             replacementNode = memberAccess.Update(memberAccess.Kind, newLeft, memberAccess.OperatorToken, memberAccess.Name).WithAdditionalAnnotations(Simplifier.Annotation)
 
                             ' Ensure that replacement doesn't change semantics.
-                            Return Not ReplacementChangesSemantics(memberAccess, replacementNode, semanticModel)
+                            Return Not ReplacementChangesSemantics(memberAccess, replacementNode, semanticModel, cancellationToken)
                         End If
 
                         Return False
@@ -1642,7 +1644,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
                             replacementNode = qualifiedName.Update(DirectCast(newLeft, NameSyntax), qualifiedName.DotToken, qualifiedName.Right).WithAdditionalAnnotations(Simplifier.Annotation)
 
                             ' Ensure that replacement doesn't change semantics.
-                            Return Not ReplacementChangesSemantics(qualifiedName, replacementNode, semanticModel)
+                            Return Not ReplacementChangesSemantics(qualifiedName, replacementNode, semanticModel, cancellationToken)
                         End If
 
                         Return False
@@ -1652,8 +1654,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             Return False
         End Function
 
-        Private Function ReplacementChangesSemantics(originalExpression As ExpressionSyntax, replacedExpression As ExpressionSyntax, semanticModel As SemanticModel) As Boolean
-            Dim speculationAnalyzer = New SpeculationAnalyzer(originalExpression, replacedExpression, semanticModel, CancellationToken.None)
+        Private Function ReplacementChangesSemantics(
+                originalExpression As ExpressionSyntax,
+                replacedExpression As ExpressionSyntax,
+                semanticModel As SemanticModel,
+                cancellationToken As CancellationToken) As Boolean
+            Dim speculationAnalyzer = New SpeculationAnalyzer(originalExpression, replacedExpression, semanticModel, cancellationToken)
             Return speculationAnalyzer.ReplacementChangesSemantics()
         End Function
 

src/Workspaces/VisualBasic/Portable/Simplification/VisualBasicSimplificationService.Expander.vb

@@ -58,9 +58,9 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Simplification
                 Return AddCast(expression, targetType, semanticModel)
             End Function
 
-            Private Shared Function AddCast(expression As ExpressionSyntax, targetType As ITypeSymbol, semanticModel As SemanticModel) As ExpressionSyntax
+            Private Function AddCast(expression As ExpressionSyntax, targetType As ITypeSymbol, semanticModel As SemanticModel) As ExpressionSyntax
                 Dim wasCastAdded As Boolean = False
-                Dim result = expression.CastIfPossible(targetType, expression.SpanStart, semanticModel, wasCastAdded)
+                Dim result = expression.CastIfPossible(targetType, expression.SpanStart, semanticModel, wasCastAdded, _cancellationToken)
 
                 If wasCastAdded Then
                     result = result.Parenthesize()