VisualBasicSyntaxFactsService.vb

' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.

Imports System.Collections.Immutable
Imports System.Composition
Imports System.Text
Imports System.Threading
Imports Microsoft.CodeAnalysis
Imports Microsoft.CodeAnalysis.Collections
Imports Microsoft.CodeAnalysis.FindSymbols
Imports Microsoft.CodeAnalysis.Host
Imports Microsoft.CodeAnalysis.Host.Mef
Imports Microsoft.CodeAnalysis.LanguageServices
Imports Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
Imports Microsoft.CodeAnalysis.VisualBasic.SyntaxFacts

Namespace Microsoft.CodeAnalysis.VisualBasic

    <ExportLanguageServiceFactory(GetType(ISyntaxFactsService), LanguageNames.VisualBasic), [Shared]>
    Friend Class VisualBasicSyntaxFactsServiceFactory
        Implements ILanguageServiceFactory

        Public Shared ReadOnly Property Instance As New VisualBasicSyntaxFactsService

        Public Function CreateLanguageService(languageServices As HostLanguageServices) As ILanguageService Implements ILanguageServiceFactory.CreateLanguageService
            Return Instance
        End Function

    End Class

    Friend Class VisualBasicSyntaxFactsService
        Inherits AbstractSyntaxFactsService
        Implements ISyntaxFactsService

        Public Function IsAwaitKeyword(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsAwaitKeyword
            Return token.Kind = SyntaxKind.AwaitKeyword
        End Function

        Public Function IsIdentifier(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsIdentifier
            Return token.Kind = SyntaxKind.IdentifierToken
        End Function

        Public Function IsGlobalNamespaceKeyword(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsGlobalNamespaceKeyword
            Return token.Kind = SyntaxKind.GlobalKeyword
        End Function

        Public Function IsVerbatimIdentifier(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsVerbatimIdentifier
            Return False
        End Function

        Public Function IsOperator(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsOperator
            Return (IsUnaryExpressionOperatorToken(CType(token.Kind, SyntaxKind)) AndAlso (TypeOf token.Parent Is UnaryExpressionSyntax OrElse TypeOf token.Parent Is OperatorStatementSyntax)) OrElse
                   (IsBinaryExpressionOperatorToken(CType(token.Kind, SyntaxKind)) AndAlso (TypeOf token.Parent Is BinaryExpressionSyntax OrElse TypeOf token.Parent Is OperatorStatementSyntax))
        End Function

        Public Function IsContextualKeyword(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsContextualKeyword
            Return token.IsContextualKeyword()
        End Function

        Public Function IsKeyword(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsKeyword
            Return token.IsKeyword()
        End Function

        Public Function IsPreprocessorKeyword(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsPreprocessorKeyword
            Return token.IsPreprocessorKeyword()
        End Function

        Public Function IsHashToken(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsHashToken
            Return token.Kind = SyntaxKind.HashToken
        End Function

        Public Function TryGetCorrespondingOpenBrace(token As SyntaxToken, ByRef openBrace As SyntaxToken) As Boolean Implements ISyntaxFactsService.TryGetCorrespondingOpenBrace

            If token.Kind = SyntaxKind.CloseBraceToken Then
                Dim tuples = token.Parent.GetBraces()
                openBrace = tuples.Item1
                Return openBrace.Kind = SyntaxKind.OpenBraceToken
            End If

            Return False
        End Function

        Public Function IsInInactiveRegion(syntaxTree As SyntaxTree, position As Integer, cancellationToken As CancellationToken) As Boolean Implements ISyntaxFactsService.IsInInactiveRegion
            Dim vbTree = TryCast(syntaxTree, SyntaxTree)
            If vbTree Is Nothing Then
                Return False
            End If

            Return vbTree.IsInInactiveRegion(position, cancellationToken)
        End Function

        Public Function IsInNonUserCode(syntaxTree As SyntaxTree, position As Integer, cancellationToken As CancellationToken) As Boolean Implements ISyntaxFactsService.IsInNonUserCode
            Dim vbTree = TryCast(syntaxTree, SyntaxTree)
            If vbTree Is Nothing Then
                Return False
            End If

            Return vbTree.IsInNonUserCode(position, cancellationToken)
        End Function

        Public Function IsEntirelyWithinStringOrCharOrNumericLiteral(syntaxTree As SyntaxTree, position As Integer, cancellationToken As CancellationToken) As Boolean Implements ISyntaxFactsService.IsEntirelyWithinStringOrCharOrNumericLiteral
            Dim vbTree = TryCast(syntaxTree, SyntaxTree)
            If vbTree Is Nothing Then
                Return False
            End If

            Return vbTree.IsEntirelyWithinStringOrCharOrNumericLiteral(position, cancellationToken)
        End Function

        Public Function IsDirective(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsDirective
            Return TypeOf node Is DirectiveTriviaSyntax
        End Function

        Public Function TryGetExternalSourceInfo(node As SyntaxNode, ByRef info As ExternalSourceInfo) As Boolean Implements ISyntaxFactsService.TryGetExternalSourceInfo
            Select Case node.Kind
                Case SyntaxKind.ExternalSourceDirectiveTrivia
                    info = New ExternalSourceInfo(CInt(DirectCast(node, ExternalSourceDirectiveTriviaSyntax).LineStart.Value), False)
                    Return True

                Case SyntaxKind.EndExternalSourceDirectiveTrivia
                    info = New ExternalSourceInfo(Nothing, True)
                    Return True
            End Select

            Return False
        End Function

        Public Function IsObjectCreationExpressionType(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsObjectCreationExpressionType
            Return node.IsParentKind(SyntaxKind.ObjectCreationExpression) AndAlso
                DirectCast(node.Parent, ObjectCreationExpressionSyntax).Type Is node
        End Function

        Public Function IsAttributeName(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsAttributeName
            Return node.IsParentKind(SyntaxKind.Attribute) AndAlso
                DirectCast(node.Parent, AttributeSyntax).Name Is node
        End Function

        Public Function IsRightSideOfQualifiedName(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsRightSideOfQualifiedName
            Dim vbNode = TryCast(node, SimpleNameSyntax)
            Return vbNode IsNot Nothing AndAlso vbNode.IsRightSideOfQualifiedName()
        End Function

        Public Function IsMemberAccessExpressionName(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsMemberAccessExpressionName
            Dim vbNode = TryCast(node, SimpleNameSyntax)
            Return vbNode IsNot Nothing AndAlso vbNode.IsMemberAccessExpressionName()
        End Function

        Public Function IsConditionalMemberAccessExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsConditionalMemberAccessExpression
            Return TypeOf node Is ConditionalAccessExpressionSyntax
        End Function

        Public Function IsInvocationExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInvocationExpression
            Return TypeOf node Is InvocationExpressionSyntax
        End Function

        Public Function IsAnonymousFunction(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsAnonymousFunction
            Return TypeOf node Is LambdaExpressionSyntax
        End Function

        Public Function IsGenericName(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsGenericName
            Return TypeOf node Is GenericNameSyntax
        End Function

        Public Function IsNamedParameter(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsNamedParameter
            Return node.CheckParent(Of SimpleArgumentSyntax)(Function(p) p.IsNamed AndAlso p.NameColonEquals.Name Is node)
        End Function

        Public Function IsSkippedTokensTrivia(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsSkippedTokensTrivia
            Return TypeOf node Is SkippedTokensTriviaSyntax
        End Function

        Public Function HasIncompleteParentMember(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.HasIncompleteParentMember
            Return node.IsParentKind(SyntaxKind.IncompleteMember)
        End Function

        Public Function GetIdentifierOfGenericName(genericName As SyntaxNode) As SyntaxToken Implements ISyntaxFactsService.GetIdentifierOfGenericName
            Dim vbGenericName = TryCast(genericName, GenericNameSyntax)
            Return If(vbGenericName IsNot Nothing, vbGenericName.Identifier, Nothing)
        End Function

        Public ReadOnly Property IsCaseSensitive As Boolean Implements ISyntaxFactsService.IsCaseSensitive
            Get
                Return False
            End Get
        End Property

        Public Function IsUsingDirectiveName(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsUsingDirectiveName
            Return node.IsParentKind(SyntaxKind.SimpleImportsClause) AndAlso
                   DirectCast(node.Parent, SimpleImportsClauseSyntax).Name Is node
        End Function

        Public Function IsForEachStatement(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsForEachStatement
            Return TypeOf node Is ForEachStatementSyntax
        End Function

        Public Function IsLockStatement(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsLockStatement
            Return TypeOf node Is SyncLockStatementSyntax
        End Function

        Public Function IsUsingStatement(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsUsingStatement
            Return TypeOf node Is UsingStatementSyntax
        End Function

        Public Function IsThisConstructorInitializer(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsThisConstructorInitializer
            If TypeOf token.Parent Is IdentifierNameSyntax AndAlso token.HasMatchingText(SyntaxKind.NewKeyword) Then
                Dim memberAccess = TryCast(token.Parent.Parent, MemberAccessExpressionSyntax)
                Return memberAccess.IsThisConstructorInitializer()
            End If

            Return False
        End Function

        Public Function IsBaseConstructorInitializer(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsBaseConstructorInitializer
            If TypeOf token.Parent Is IdentifierNameSyntax AndAlso token.HasMatchingText(SyntaxKind.NewKeyword) Then
                Dim memberAccess = TryCast(token.Parent.Parent, MemberAccessExpressionSyntax)
                Return memberAccess.IsBaseConstructorInitializer()
            End If

            Return False
        End Function

        Public Function IsQueryExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsQueryExpression
            Return TypeOf node Is QueryExpressionSyntax
        End Function

        Public Function IsPredefinedType(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsPredefinedType
            Dim actualType As PredefinedType = PredefinedType.None
            Return TryGetPredefinedType(token, actualType) AndAlso actualType <> PredefinedType.None
        End Function

        Public Function IsPredefinedType(token As SyntaxToken, type As PredefinedType) As Boolean Implements ISyntaxFactsService.IsPredefinedType
            Dim actualType As PredefinedType = PredefinedType.None
            Return TryGetPredefinedType(token, actualType) AndAlso actualType = type
        End Function

        Public Function TryGetPredefinedType(token As SyntaxToken, ByRef type As PredefinedType) As Boolean Implements ISyntaxFactsService.TryGetPredefinedType
            type = GetPredefinedType(token)
            Return type <> PredefinedType.None
        End Function

        Private Function GetPredefinedType(token As SyntaxToken) As PredefinedType
            Select Case token.Kind
                Case SyntaxKind.BooleanKeyword
                    Return PredefinedType.Boolean
                Case SyntaxKind.ByteKeyword
                    Return PredefinedType.Byte
                Case SyntaxKind.SByteKeyword
                    Return PredefinedType.SByte
                Case SyntaxKind.IntegerKeyword
                    Return PredefinedType.Int32
                Case SyntaxKind.UIntegerKeyword
                    Return PredefinedType.UInt32
                Case SyntaxKind.ShortKeyword
                    Return PredefinedType.Int16
                Case SyntaxKind.UShortKeyword
                    Return PredefinedType.UInt16
                Case SyntaxKind.LongKeyword
                    Return PredefinedType.Int64
                Case SyntaxKind.ULongKeyword
                    Return PredefinedType.UInt64
                Case SyntaxKind.SingleKeyword
                    Return PredefinedType.Single
                Case SyntaxKind.DoubleKeyword
                    Return PredefinedType.Double
                Case SyntaxKind.DecimalKeyword
                    Return PredefinedType.Decimal
                Case SyntaxKind.StringKeyword
                    Return PredefinedType.String
                Case SyntaxKind.CharKeyword
                    Return PredefinedType.Char
                Case SyntaxKind.ObjectKeyword
                    Return PredefinedType.Object
                Case SyntaxKind.DateKeyword
                    Return PredefinedType.DateTime
                Case Else
                    Return PredefinedType.None
            End Select
        End Function

        Public Function IsPredefinedOperator(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsPredefinedOperator
            Dim actualOp As PredefinedOperator = PredefinedOperator.None
            Return TryGetPredefinedOperator(token, actualOp) AndAlso actualOp <> PredefinedOperator.None
        End Function

        Public Function IsPredefinedOperator(token As SyntaxToken, op As PredefinedOperator) As Boolean Implements ISyntaxFactsService.IsPredefinedOperator
            Dim actualOp As PredefinedOperator = PredefinedOperator.None
            Return TryGetPredefinedOperator(token, actualOp) AndAlso actualOp = op
        End Function

        Public Function TryGetPredefinedOperator(token As SyntaxToken, ByRef op As PredefinedOperator) As Boolean Implements ISyntaxFactsService.TryGetPredefinedOperator
            op = GetPredefinedOperator(token)
            Return op <> PredefinedOperator.None
        End Function

        Private Function GetPredefinedOperator(token As SyntaxToken) As PredefinedOperator
            Select Case token.Kind
                Case SyntaxKind.PlusToken, SyntaxKind.PlusEqualsToken
                    Return PredefinedOperator.Addition

                Case SyntaxKind.MinusToken, SyntaxKind.MinusEqualsToken
                    Return PredefinedOperator.Subtraction

                Case SyntaxKind.AndKeyword, SyntaxKind.AndAlsoKeyword
                    Return PredefinedOperator.BitwiseAnd

                Case SyntaxKind.OrKeyword, SyntaxKind.OrElseKeyword
                    Return PredefinedOperator.BitwiseOr

                Case SyntaxKind.AmpersandToken, SyntaxKind.AmpersandEqualsToken
                    Return PredefinedOperator.Concatenate

                Case SyntaxKind.SlashToken, SyntaxKind.SlashEqualsToken
                    Return PredefinedOperator.Division

                Case SyntaxKind.EqualsToken
                    Return PredefinedOperator.Equality

                Case SyntaxKind.XorKeyword
                    Return PredefinedOperator.ExclusiveOr

                Case SyntaxKind.CaretToken, SyntaxKind.CaretEqualsToken
                    Return PredefinedOperator.Exponent

                Case SyntaxKind.GreaterThanToken
                    Return PredefinedOperator.GreaterThan

                Case SyntaxKind.GreaterThanEqualsToken
                    Return PredefinedOperator.GreaterThanOrEqual

                Case SyntaxKind.LessThanGreaterThanToken
                    Return PredefinedOperator.Inequality

                Case SyntaxKind.BackslashToken, SyntaxKind.BackslashEqualsToken
                    Return PredefinedOperator.IntegerDivision

                Case SyntaxKind.LessThanLessThanToken, SyntaxKind.LessThanLessThanEqualsToken
                    Return PredefinedOperator.LeftShift

                Case SyntaxKind.LessThanToken
                    Return PredefinedOperator.LessThan

                Case SyntaxKind.LessThanEqualsToken
                    Return PredefinedOperator.LessThanOrEqual

                Case SyntaxKind.LikeKeyword
                    Return PredefinedOperator.Like

                Case SyntaxKind.NotKeyword
                    Return PredefinedOperator.Complement

                Case SyntaxKind.ModKeyword
                    Return PredefinedOperator.Modulus

                Case SyntaxKind.AsteriskToken, SyntaxKind.AsteriskEqualsToken
                    Return PredefinedOperator.Multiplication

                Case SyntaxKind.GreaterThanGreaterThanToken, SyntaxKind.GreaterThanGreaterThanEqualsToken
                    Return PredefinedOperator.RightShift

                Case Else
                    Return PredefinedOperator.None
            End Select
        End Function

        Public Function GetText(kind As Integer) As String Implements ISyntaxFactsService.GetText
            Return SyntaxFacts.GetText(CType(kind, SyntaxKind))
        End Function

        Public Function IsIdentifierPartCharacter(c As Char) As Boolean Implements ISyntaxFactsService.IsIdentifierPartCharacter
            Return SyntaxFacts.IsIdentifierPartCharacter(c)
        End Function

        Public Function IsIdentifierStartCharacter(c As Char) As Boolean Implements ISyntaxFactsService.IsIdentifierStartCharacter
            Return SyntaxFacts.IsIdentifierStartCharacter(c)
        End Function

        Public Function IsIdentifierEscapeCharacter(c As Char) As Boolean Implements ISyntaxFactsService.IsIdentifierEscapeCharacter
            Return c = "["c OrElse c = "]"c
        End Function

        Public Function IsValidIdentifier(identifier As String) As Boolean Implements ISyntaxFactsService.IsValidIdentifier
            Dim token = SyntaxFactory.ParseToken(identifier)
            ' TODO: There is no way to get the diagnostics to see if any are actually errors?
            Return IsIdentifier(token) AndAlso Not token.ContainsDiagnostics AndAlso token.ToString().Length = identifier.Length
        End Function

        Public Function IsVerbatimIdentifier(identifier As String) As Boolean Implements ISyntaxFactsService.IsVerbatimIdentifier
            Return IsValidIdentifier(identifier) AndAlso MakeHalfWidthIdentifier(identifier.First()) = "[" AndAlso MakeHalfWidthIdentifier(identifier.Last()) = "]"
        End Function

        Public Function IsTypeCharacter(c As Char) As Boolean Implements ISyntaxFactsService.IsTypeCharacter
            Return c = "%"c OrElse
                   c = "&"c OrElse
                   c = "@"c OrElse
                   c = "!"c OrElse
                   c = "#"c OrElse
                   c = "$"c
        End Function

        Public Function IsStartOfUnicodeEscapeSequence(c As Char) As Boolean Implements ISyntaxFactsService.IsStartOfUnicodeEscapeSequence
            Return False ' VB does not support identifiers with escaped unicode characters 
        End Function

        Public Function IsLiteral(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsLiteral
            Select Case token.Kind()
                Case _
                        SyntaxKind.IntegerLiteralToken,
                        SyntaxKind.CharacterLiteralToken,
                        SyntaxKind.DecimalLiteralToken,
                        SyntaxKind.FloatingLiteralToken,
                        SyntaxKind.DateLiteralToken,
                        SyntaxKind.StringLiteralToken,
                        SyntaxKind.DollarSignDoubleQuoteToken,
                        SyntaxKind.DoubleQuoteToken,
                        SyntaxKind.InterpolatedStringTextToken,
                        SyntaxKind.TrueKeyword,
                        SyntaxKind.FalseKeyword,
                        SyntaxKind.NothingKeyword
                    Return True
            End Select

            Return False
        End Function

        Public Function IsStringLiteralOrInterpolatedStringLiteral(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsStringLiteralOrInterpolatedStringLiteral
            Return token.IsKind(SyntaxKind.StringLiteralToken, SyntaxKind.InterpolatedStringTextToken)
        End Function

        Public Function IsNumericLiteralExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsNumericLiteralExpression
            Return If(node Is Nothing, False, node.IsKind(SyntaxKind.NumericLiteralExpression))
        End Function

        Public Function IsBindableToken(token As Microsoft.CodeAnalysis.SyntaxToken) As Boolean Implements ISyntaxFactsService.IsBindableToken
            Return Me.IsWord(token) OrElse
                Me.IsLiteral(token) OrElse
                Me.IsOperator(token)
        End Function

        Public Function IsMemberAccessExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsMemberAccessExpression
            Return TypeOf node Is MemberAccessExpressionSyntax AndAlso
                DirectCast(node, MemberAccessExpressionSyntax).Kind = SyntaxKind.SimpleMemberAccessExpression
        End Function

        Public Function IsPointerMemberAccessExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsPointerMemberAccessExpression
            Return False
        End Function

        Public Sub GetNameAndArityOfSimpleName(node As SyntaxNode, ByRef name As String, ByRef arity As Integer) Implements ISyntaxFactsService.GetNameAndArityOfSimpleName
            Dim simpleName = TryCast(node, SimpleNameSyntax)
            If simpleName IsNot Nothing Then
                name = simpleName.Identifier.ValueText
                arity = simpleName.Arity
            End If
        End Sub

        Public Function GetExpressionOfMemberAccessExpression(node As SyntaxNode) As Microsoft.CodeAnalysis.SyntaxNode Implements ISyntaxFactsService.GetExpressionOfMemberAccessExpression
            Return TryCast(node, MemberAccessExpressionSyntax)?.GetExpressionOfMemberAccessExpression()
        End Function

        Public Function GetExpressionOfConditionalMemberAccessExpression(node As SyntaxNode) As SyntaxNode Implements ISyntaxFactsService.GetExpressionOfConditionalMemberAccessExpression
            Return TryCast(node, ConditionalAccessExpressionSyntax)?.Expression
        End Function

        Public Function GetExpressionOfInterpolation(node As SyntaxNode) As SyntaxNode Implements ISyntaxFactsService.GetExpressionOfInterpolation
            Return TryCast(node, InterpolationSyntax)?.Expression
        End Function

        Public Function IsInNamespaceOrTypeContext(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInNamespaceOrTypeContext
            Return SyntaxFacts.IsInNamespaceOrTypeContext(node)
        End Function

        Public Function IsInStaticContext(node As Microsoft.CodeAnalysis.SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInStaticContext
            Return node.IsInStaticContext()
        End Function

        Public Function GetExpressionOfArgument(node As Microsoft.CodeAnalysis.SyntaxNode) As Microsoft.CodeAnalysis.SyntaxNode Implements ISyntaxFactsService.GetExpressionOfArgument
            Return TryCast(node, ArgumentSyntax).GetArgumentExpression()
        End Function

        Public Function GetRefKindOfArgument(node As Microsoft.CodeAnalysis.SyntaxNode) As Microsoft.CodeAnalysis.RefKind Implements ISyntaxFactsService.GetRefKindOfArgument
            ' TODO(cyrusn): Consider the method this argument is passed to, to determine this.
            Return RefKind.None
        End Function

        Public Function IsInConstantContext(node As Microsoft.CodeAnalysis.SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInConstantContext
            Return node.IsInConstantContext()
        End Function

        Public Function IsInConstructor(node As Microsoft.CodeAnalysis.SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInConstructor
            Return node.GetAncestors(Of StatementSyntax).Any(Function(s) s.Kind = SyntaxKind.ConstructorBlock)
        End Function

        Public Function IsUnsafeContext(node As Microsoft.CodeAnalysis.SyntaxNode) As Boolean Implements ISyntaxFactsService.IsUnsafeContext
            Return False
        End Function

        Public Function GetNameOfAttribute(node As Microsoft.CodeAnalysis.SyntaxNode) As Microsoft.CodeAnalysis.SyntaxNode Implements ISyntaxFactsService.GetNameOfAttribute
            Return DirectCast(node, AttributeSyntax).Name
        End Function

        Public Function IsAttribute(node As Microsoft.CodeAnalysis.SyntaxNode) As Boolean Implements ISyntaxFactsService.IsAttribute
            Return TypeOf node Is AttributeSyntax
        End Function

        Public Function IsAttributeNamedArgumentIdentifier(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsAttributeNamedArgumentIdentifier
            Dim identifierName = TryCast(node, IdentifierNameSyntax)
            Return identifierName.IsParentKind(SyntaxKind.NameColonEquals) AndAlso
                identifierName.Parent.IsParentKind(SyntaxKind.SimpleArgument) AndAlso
                identifierName.Parent.Parent.IsParentKind(SyntaxKind.ArgumentList) AndAlso
                identifierName.Parent.Parent.Parent.IsParentKind(SyntaxKind.Attribute)
        End Function

        Public Function GetContainingTypeDeclaration(root As SyntaxNode, position As Integer) As SyntaxNode Implements ISyntaxFactsService.GetContainingTypeDeclaration
            If root Is Nothing Then
                Throw New ArgumentNullException(NameOf(root))
            End If

            If position < 0 OrElse position > root.Span.End Then
                Throw New ArgumentOutOfRangeException(NameOf(position))
            End If

            Return root.
                FindToken(position).
                GetAncestors(Of SyntaxNode)().
                FirstOrDefault(Function(n) TypeOf n Is TypeBlockSyntax OrElse TypeOf n Is DelegateStatementSyntax)
        End Function

        Public Function GetContainingVariableDeclaratorOfFieldDeclaration(node As SyntaxNode) As SyntaxNode Implements ISyntaxFactsService.GetContainingVariableDeclaratorOfFieldDeclaration
            If node Is Nothing Then
                Throw New ArgumentNullException(NameOf(node))
            End If

            Dim parent = node.Parent

            While node IsNot Nothing
                If node.Kind = SyntaxKind.VariableDeclarator AndAlso node.IsParentKind(SyntaxKind.FieldDeclaration) Then
                    Return node
                End If

                node = node.Parent
            End While

            Return Nothing
        End Function

        Public Function FindTokenOnLeftOfPosition(node As SyntaxNode,
                                                  position As Integer,
                                                  Optional includeSkipped As Boolean = True,
                                                  Optional includeDirectives As Boolean = False,
                                                  Optional includeDocumentationComments As Boolean = False) As SyntaxToken Implements ISyntaxFactsService.FindTokenOnLeftOfPosition
            Return node.FindTokenOnLeftOfPosition(position, includeSkipped, includeDirectives, includeDocumentationComments)
        End Function

        Public Function FindTokenOnRightOfPosition(node As SyntaxNode,
                                                   position As Integer,
                                                   Optional includeSkipped As Boolean = True,
                                                   Optional includeDirectives As Boolean = False,
                                                   Optional includeDocumentationComments As Boolean = False) As SyntaxToken Implements ISyntaxFactsService.FindTokenOnRightOfPosition
            Return node.FindTokenOnRightOfPosition(position, includeSkipped, includeDirectives, includeDocumentationComments)
        End Function

        Public Function IsObjectCreationExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsObjectCreationExpression
            Return TypeOf node Is ObjectCreationExpressionSyntax
        End Function

        Public Function IsObjectInitializerNamedAssignmentIdentifier(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsObjectInitializerNamedAssignmentIdentifier
            Dim unused As SyntaxNode = Nothing
            Return IsObjectInitializerNamedAssignmentIdentifier(node, unused)
        End Function

        Public Function IsObjectInitializerNamedAssignmentIdentifier(
                node As SyntaxNode,
                ByRef initializedInstance As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsObjectInitializerNamedAssignmentIdentifier

            Dim identifier = TryCast(node, IdentifierNameSyntax)
            If identifier?.IsChildNode(Of NamedFieldInitializerSyntax)(Function(n) n.Name) Then
                ' .parent is the NamedField.
                ' .parent.parent is the ObjectInitializer.
                ' .parent.parent.parent will be the ObjectCreationExpression.
                initializedInstance = identifier.Parent.Parent.Parent
                Return True
            End If

            Return False
        End Function

        Public Function IsElementAccessExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsElementAccessExpression
            ' VB doesn't have a specialized node for element access.  Instead, it just uses an
            ' invocation expression or dictionary access expression.
            Return node.Kind = SyntaxKind.InvocationExpression OrElse node.Kind = SyntaxKind.DictionaryAccessExpression
        End Function

        Public Function ToIdentifierToken(name As String) As SyntaxToken Implements ISyntaxFactsService.ToIdentifierToken
            Return name.ToIdentifierToken()
        End Function

        Public Function Parenthesize(expression As SyntaxNode, Optional includeElasticTrivia As Boolean = True) As SyntaxNode Implements ISyntaxFactsService.Parenthesize
            Return DirectCast(expression, ExpressionSyntax).Parenthesize()
        End Function

        Public Function IsTypeNamedVarInVariableOrFieldDeclaration(token As SyntaxToken, parent As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsTypeNamedVarInVariableOrFieldDeclaration
            Return False
        End Function

        Public Function IsTypeNamedDynamic(token As SyntaxToken, parent As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsTypeNamedDynamic
            Return False
        End Function

        Public Function IsIndexerMemberCRef(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsIndexerMemberCRef
            Return False
        End Function

        Public Function GetContainingMemberDeclaration(root As SyntaxNode, position As Integer, Optional useFullSpan As Boolean = True) As SyntaxNode Implements ISyntaxFactsService.GetContainingMemberDeclaration
            Contract.ThrowIfNull(root, NameOf(root))
            Contract.ThrowIfTrue(position < 0 OrElse position > root.FullSpan.End, NameOf(position))

            Dim [end] = root.FullSpan.End
            If [end] = 0 Then
                ' empty file
                Return Nothing
            End If

            ' make sure position doesn't touch end of root
            position = Math.Min(position, [end] - 1)

            Dim node = root.FindToken(position).Parent
            While node IsNot Nothing
                If useFullSpan OrElse node.Span.Contains(position) Then

                    If TypeOf node Is MethodBlockBaseSyntax AndAlso Not TypeOf node.Parent Is PropertyBlockSyntax Then
                        Return node
                    End If

                    If TypeOf node Is PropertyStatementSyntax AndAlso Not TypeOf node.Parent Is PropertyBlockSyntax Then
                        Return node
                    End If

                    If TypeOf node Is EventStatementSyntax AndAlso Not TypeOf node.Parent Is EventBlockSyntax Then
                        Return node
                    End If

                    If TypeOf node Is PropertyBlockSyntax OrElse
                       TypeOf node Is TypeBlockSyntax OrElse
                       TypeOf node Is EnumBlockSyntax OrElse
                       TypeOf node Is NamespaceBlockSyntax OrElse
                       TypeOf node Is EventBlockSyntax OrElse
                       TypeOf node Is FieldDeclarationSyntax Then
                        Return node
                    End If
                End If

                node = node.Parent
            End While

            Return Nothing
        End Function

        Public Function IsMethodLevelMember(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsMethodLevelMember

            ' Note: Derived types of MethodBaseSyntax are expanded explicitly, since PropertyStatementSyntax and
            ' EventStatementSyntax will NOT be parented by MethodBlockBaseSyntax.  Additionally, there are things
            ' like AccessorStatementSyntax and DelegateStatementSyntax that we never want to tread as method level
            ' members.

            If TypeOf node Is MethodStatementSyntax AndAlso Not TypeOf node.Parent Is MethodBlockBaseSyntax Then
                Return True
            End If

            If TypeOf node Is SubNewStatementSyntax AndAlso Not TypeOf node.Parent Is MethodBlockBaseSyntax Then
                Return True
            End If

            If TypeOf node Is OperatorStatementSyntax AndAlso Not TypeOf node.Parent Is MethodBlockBaseSyntax Then
                Return True
            End If

            If TypeOf node Is PropertyStatementSyntax AndAlso Not TypeOf node.Parent Is PropertyBlockSyntax Then
                Return True
            End If

            If TypeOf node Is EventStatementSyntax AndAlso Not TypeOf node.Parent Is EventBlockSyntax Then
                Return True
            End If

            If TypeOf node Is DeclareStatementSyntax Then
                Return True
            End If

            Return TypeOf node Is ConstructorBlockSyntax OrElse
                   TypeOf node Is MethodBlockSyntax OrElse
                   TypeOf node Is OperatorBlockSyntax OrElse
                   TypeOf node Is EventBlockSyntax OrElse
                   TypeOf node Is PropertyBlockSyntax OrElse
                   TypeOf node Is EnumMemberDeclarationSyntax OrElse
                   TypeOf node Is FieldDeclarationSyntax
        End Function

        Public Function GetMemberBodySpanForSpeculativeBinding(node As SyntaxNode) As TextSpan Implements ISyntaxFactsService.GetMemberBodySpanForSpeculativeBinding
            Dim member = GetContainingMemberDeclaration(node, node.SpanStart)
            If member Is Nothing Then
                Return Nothing
            End If

            ' TODO: currently we only support method for now
            Dim method = TryCast(member, MethodBlockBaseSyntax)
            If method IsNot Nothing Then
                If method.BlockStatement Is Nothing OrElse method.EndBlockStatement Is Nothing Then
                    Return Nothing
                End If

                ' We don't want to include the BlockStatement or any trailing trivia up to and including its statement
                ' terminator in the span. Instead, we use the start of the first statement's leading trivia (if any) up
                ' to the start of the EndBlockStatement. If there aren't any statements in the block, we use the start
                ' of the EndBlockStatements leading trivia.

                Dim firstStatement = method.Statements.FirstOrDefault()
                Dim spanStart = If(firstStatement IsNot Nothing,
                                   firstStatement.FullSpan.Start,
                                   method.EndBlockStatement.FullSpan.Start)

                Return TextSpan.FromBounds(spanStart, method.EndBlockStatement.SpanStart)
            End If

            Return Nothing
        End Function

        Public Function ContainsInMemberBody(node As SyntaxNode, span As TextSpan) As Boolean Implements ISyntaxFactsService.ContainsInMemberBody
            Dim method = TryCast(node, MethodBlockBaseSyntax)
            If method IsNot Nothing Then
                Return method.Statements.Count > 0 AndAlso ContainsExclusively(GetSyntaxListSpan(method.Statements), span)
            End If

            Dim [event] = TryCast(node, EventBlockSyntax)
            If [event] IsNot Nothing Then
                Return [event].Accessors.Count > 0 AndAlso ContainsExclusively(GetSyntaxListSpan([event].Accessors), span)
            End If

            Dim [property] = TryCast(node, PropertyBlockSyntax)
            If [property] IsNot Nothing Then
                Return [property].Accessors.Count > 0 AndAlso ContainsExclusively(GetSyntaxListSpan([property].Accessors), span)
            End If

            Dim field = TryCast(node, FieldDeclarationSyntax)
            If field IsNot Nothing Then
                Return field.Declarators.Count > 0 AndAlso ContainsExclusively(GetSeparatedSyntaxListSpan(field.Declarators), span)
            End If

            Dim [enum] = TryCast(node, EnumMemberDeclarationSyntax)
            If [enum] IsNot Nothing Then
                Return [enum].Initializer IsNot Nothing AndAlso ContainsExclusively([enum].Initializer.Span, span)
            End If

            Dim propStatement = TryCast(node, PropertyStatementSyntax)
            If propStatement IsNot Nothing Then
                Return propStatement.Initializer IsNot Nothing AndAlso ContainsExclusively(propStatement.Initializer.Span, span)
            End If

            Return False
        End Function

        Private Function ContainsExclusively(outerSpan As TextSpan, innerSpan As TextSpan) As Boolean
            If innerSpan.IsEmpty Then
                Return outerSpan.Contains(innerSpan.Start)
            End If

            Return outerSpan.Contains(innerSpan)
        End Function

        Private Function GetSyntaxListSpan(Of T As SyntaxNode)(list As SyntaxList(Of T)) As TextSpan
            Contract.Requires(list.Count > 0)
            Return TextSpan.FromBounds(list.First.SpanStart, list.Last.Span.End)
        End Function

        Private Function GetSeparatedSyntaxListSpan(Of T As SyntaxNode)(list As SeparatedSyntaxList(Of T)) As TextSpan
            Contract.Requires(list.Count > 0)
            Return TextSpan.FromBounds(list.First.SpanStart, list.Last.Span.End)
        End Function

        Public Function GetMethodLevelMembers(root As SyntaxNode) As List(Of SyntaxNode) Implements ISyntaxFactsService.GetMethodLevelMembers
            Dim list = New List(Of SyntaxNode)()
            AppendMethodLevelMembers(root, list)
            Return list
        End Function

        Public Function IsTopLevelNodeWithMembers(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsTopLevelNodeWithMembers
            Return TypeOf node Is NamespaceBlockSyntax OrElse
                   TypeOf node Is TypeBlockSyntax OrElse
                   TypeOf node Is EnumBlockSyntax
        End Function

        Public Function TryGetDeclaredSymbolInfo(node As SyntaxNode, ByRef declaredSymbolInfo As DeclaredSymbolInfo) As Boolean Implements ISyntaxFactsService.TryGetDeclaredSymbolInfo
            Select Case node.Kind()
                Case SyntaxKind.ClassBlock
                    Dim classDecl = CType(node, ClassBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        classDecl.ClassStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Class, classDecl.ClassStatement.Identifier.Span,
                        GetInheritanceNames(classDecl))
                    Return True
                Case SyntaxKind.ConstructorBlock
                    Dim constructor = CType(node, ConstructorBlockSyntax)
                    Dim typeBlock = TryCast(constructor.Parent, TypeBlockSyntax)
                    If typeBlock IsNot Nothing Then
                        declaredSymbolInfo = New DeclaredSymbolInfo(
                            typeBlock.BlockStatement.Identifier.ValueText,
                            GetContainerDisplayName(node.Parent),
                            GetFullyQualifiedContainerName(node.Parent),
                            DeclaredSymbolInfoKind.Constructor,
                            constructor.SubNewStatement.NewKeyword.Span,
                            ImmutableArray(Of String).Empty,
                            parameterCount:=CType(If(constructor.SubNewStatement.ParameterList?.Parameters.Count, 0), UShort))

                        Return True
                    End If
                Case SyntaxKind.DelegateFunctionStatement, SyntaxKind.DelegateSubStatement
                    Dim delegateDecl = CType(node, DelegateStatementSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        delegateDecl.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Delegate, delegateDecl.Identifier.Span,
                        ImmutableArray(Of String).Empty)
                    Return True
                Case SyntaxKind.EnumBlock
                    Dim enumDecl = CType(node, EnumBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        enumDecl.EnumStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Enum, enumDecl.EnumStatement.Identifier.Span,
                        ImmutableArray(Of String).Empty)
                    Return True
                Case SyntaxKind.EnumMemberDeclaration
                    Dim enumMember = CType(node, EnumMemberDeclarationSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        enumMember.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.EnumMember, enumMember.Identifier.Span,
                        ImmutableArray(Of String).Empty)
                    Return True
                Case SyntaxKind.EventStatement
                    Dim eventDecl = CType(node, EventStatementSyntax)
                    Dim eventParent = If(TypeOf node.Parent Is EventBlockSyntax, node.Parent.Parent, node.Parent)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        eventDecl.Identifier.ValueText,
                        GetContainerDisplayName(eventParent),
                        GetFullyQualifiedContainerName(eventParent),
                        DeclaredSymbolInfoKind.Event, eventDecl.Identifier.Span,
                        ImmutableArray(Of String).Empty)
                    Return True
                Case SyntaxKind.FunctionBlock, SyntaxKind.SubBlock
                    Dim funcDecl = CType(node, MethodBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        funcDecl.SubOrFunctionStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Method,
                        funcDecl.SubOrFunctionStatement.Identifier.Span,
                        ImmutableArray(Of String).Empty,
                        parameterCount:=CType(If(funcDecl.SubOrFunctionStatement.ParameterList?.Parameters.Count, 0), UShort),
                        typeParameterCount:=CType(If(funcDecl.SubOrFunctionStatement.TypeParameterList?.Parameters.Count, 0), UShort))
                    Return True
                Case SyntaxKind.InterfaceBlock
                    Dim interfaceDecl = CType(node, InterfaceBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        interfaceDecl.InterfaceStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Interface, interfaceDecl.InterfaceStatement.Identifier.Span,
                        GetInheritanceNames(interfaceDecl))
                    Return True
                Case SyntaxKind.ModifiedIdentifier
                    Dim modifiedIdentifier = CType(node, ModifiedIdentifierSyntax)
                    Dim variableDeclarator = TryCast(modifiedIdentifier.Parent, VariableDeclaratorSyntax)
                    Dim fieldDecl = TryCast(variableDeclarator?.Parent, FieldDeclarationSyntax)
                    If fieldDecl IsNot Nothing Then
                        Dim kind = If(fieldDecl.Modifiers.Any(Function(m) m.Kind() = SyntaxKind.ConstKeyword),
                            DeclaredSymbolInfoKind.Constant,
                            DeclaredSymbolInfoKind.Field)
                        declaredSymbolInfo = New DeclaredSymbolInfo(
                            modifiedIdentifier.Identifier.ValueText,
                            GetContainerDisplayName(fieldDecl.Parent),
                            GetFullyQualifiedContainerName(fieldDecl.Parent),
                            kind, modifiedIdentifier.Identifier.Span,
                            ImmutableArray(Of String).Empty)
                        Return True
                    End If
                Case SyntaxKind.ModuleBlock
                    Dim moduleDecl = CType(node, ModuleBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        moduleDecl.ModuleStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Module, moduleDecl.ModuleStatement.Identifier.Span,
                        GetInheritanceNames(moduleDecl))
                    Return True
                Case SyntaxKind.PropertyStatement
                    Dim propertyDecl = CType(node, PropertyStatementSyntax)
                    Dim propertyParent = If(TypeOf node.Parent Is PropertyBlockSyntax, node.Parent.Parent, node.Parent)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        propertyDecl.Identifier.ValueText,
                        GetContainerDisplayName(propertyParent),
                        GetFullyQualifiedContainerName(propertyParent),
                        DeclaredSymbolInfoKind.Property, propertyDecl.Identifier.Span,
                        ImmutableArray(Of String).Empty)
                    Return True
                Case SyntaxKind.StructureBlock
                    Dim structDecl = CType(node, StructureBlockSyntax)
                    declaredSymbolInfo = New DeclaredSymbolInfo(
                        structDecl.StructureStatement.Identifier.ValueText,
                        GetContainerDisplayName(node.Parent),
                        GetFullyQualifiedContainerName(node.Parent),
                        DeclaredSymbolInfoKind.Struct, structDecl.StructureStatement.Identifier.Span,
                        GetInheritanceNames(structDecl))
                    Return True
            End Select

            declaredSymbolInfo = Nothing
            Return False
        End Function

        Private Function GetInheritanceNames(typeBlock As TypeBlockSyntax) As ImmutableArray(Of String)
            Dim builder = ImmutableArray.CreateBuilder(Of String)

            Dim aliasMap = GetAliasMap(typeBlock)
            Try
                For Each inheritsStatement In typeBlock.Inherits
                    AddInheritanceNames(builder, inheritsStatement.Types, aliasMap)
                Next

                For Each implementsStatement In typeBlock.Implements
                    AddInheritanceNames(builder, implementsStatement.Types, aliasMap)
                Next

                Return builder.ToImmutable()
            Finally
                FreeAliasMap(aliasMap)
            End Try
        End Function

        Private Function GetAliasMap(typeBlock As TypeBlockSyntax) As Dictionary(Of String, String)
            Dim compilationUnit = typeBlock.SyntaxTree.GetCompilationUnitRoot()

            Dim aliasMap As Dictionary(Of String, String) = Nothing
            For Each import In compilationUnit.Imports
                For Each clause In import.ImportsClauses
                    If clause.IsKind(SyntaxKind.SimpleImportsClause) Then
                        Dim simpleImport = DirectCast(clause, SimpleImportsClauseSyntax)
                        If simpleImport.Alias IsNot Nothing Then
                            Dim mappedName = GetTypeName(simpleImport.Name)
                            If mappedName IsNot Nothing Then
                                aliasMap = If(aliasMap, AllocateAliasMap())
                                aliasMap(simpleImport.Alias.Identifier.ValueText) = mappedName
                            End If
                        End If
                    End If
                Next
            Next

            Return aliasMap
        End Function

        Private Sub AddInheritanceNames(
                builder As ImmutableArray(Of String).Builder,
                types As SeparatedSyntaxList(Of TypeSyntax),
                aliasMap As Dictionary(Of String, String))

            For Each typeSyntax In types
                AddInheritanceName(builder, typeSyntax, aliasMap)
            Next
        End Sub

        Private Sub AddInheritanceName(
                builder As ImmutableArray(Of String).Builder,
                typeSyntax As TypeSyntax,
                aliasMap As Dictionary(Of String, String))
            Dim name = GetTypeName(typeSyntax)
            If name IsNot Nothing Then
                builder.Add(name)

                Dim mappedName As String = Nothing
                If aliasMap?.TryGetValue(name, mappedName) = True Then
                    ' Looks Like this could be an alias.  Also include the name the alias points to
                    builder.Add(mappedName)
                End If
            End If
        End Sub

        Private Function GetTypeName(typeSyntax As TypeSyntax) As String
            If TypeOf typeSyntax Is SimpleNameSyntax Then
                Return GetSimpleName(DirectCast(typeSyntax, SimpleNameSyntax))
            ElseIf TypeOf typeSyntax Is QualifiedNameSyntax Then
                Return GetSimpleName(DirectCast(typeSyntax, QualifiedNameSyntax).Right)
            End If

            Return Nothing
        End Function

        Private Function GetSimpleName(simpleName As SimpleNameSyntax) As String
            Return simpleName.Identifier.ValueText
        End Function

        Private Function GetContainerDisplayName(node As SyntaxNode) As String
            Return GetDisplayName(node, DisplayNameOptions.IncludeTypeParameters)
        End Function

        Private Function GetFullyQualifiedContainerName(node As SyntaxNode) As String
            Return GetDisplayName(node, DisplayNameOptions.IncludeNamespaces)
        End Function

        Private Const s_dotToken As String = "."

        Public Function GetDisplayName(node As SyntaxNode, options As DisplayNameOptions, Optional rootNamespace As String = Nothing) As String Implements ISyntaxFactsService.GetDisplayName
            If node Is Nothing Then
                Return String.Empty
            End If

            Dim pooled = PooledStringBuilder.GetInstance()
            Dim builder = pooled.Builder

            ' member keyword (if any)
            Dim memberDeclaration = TryCast(node, DeclarationStatementSyntax)
            If (options And DisplayNameOptions.IncludeMemberKeyword) <> 0 Then
                Dim keywordToken = memberDeclaration.GetMemberKeywordToken()
                If keywordToken <> Nothing AndAlso Not keywordToken.IsMissing Then
                    builder.Append(keywordToken.Text)
                    builder.Append(" "c)
                End If
            End If

            Dim names = ArrayBuilder(Of String).GetInstance()
            ' containing type(s)
            Dim parent = node.Parent
            While TypeOf parent Is TypeBlockSyntax
                names.Push(GetName(parent, options, containsGlobalKeyword:=False))
                parent = parent.Parent
            End While
            If (options And DisplayNameOptions.IncludeNamespaces) <> 0 Then
                ' containing namespace(s) in source (if any)
                Dim containsGlobalKeyword As Boolean = False
                While parent IsNot Nothing AndAlso parent.Kind() = SyntaxKind.NamespaceBlock
                    names.Push(GetName(parent, options, containsGlobalKeyword))
                    parent = parent.Parent
                End While
                ' root namespace (if any)
                If Not containsGlobalKeyword AndAlso Not String.IsNullOrEmpty(rootNamespace) Then
                    builder.Append(rootNamespace)
                    builder.Append(s_dotToken)
                End If
            End If
            While Not names.IsEmpty()
                Dim name = names.Pop()
                If name IsNot Nothing Then
                    builder.Append(name)
                    builder.Append(s_dotToken)
                End If
            End While
            names.Free()

            ' name (include generic type parameters)
            builder.Append(GetName(node, options, containsGlobalKeyword:=False))

            ' parameter list (if any)
            If (options And DisplayNameOptions.IncludeParameters) <> 0 Then
                builder.Append(memberDeclaration.GetParameterList())
            End If

            ' As clause (if any)
            If (options And DisplayNameOptions.IncludeType) <> 0 Then
                Dim asClause = memberDeclaration.GetAsClause()
                If asClause IsNot Nothing Then
                    builder.Append(" "c)
                    builder.Append(asClause)
                End If
            End If

            Return pooled.ToStringAndFree()
        End Function

        Private Shared Function GetName(node As SyntaxNode, options As DisplayNameOptions, ByRef containsGlobalKeyword As Boolean) As String
            Const missingTokenPlaceholder As String = "?"

            Select Case node.Kind()
                Case SyntaxKind.CompilationUnit
                    Return Nothing
                Case SyntaxKind.IdentifierName
                    Dim identifier = DirectCast(node, IdentifierNameSyntax).Identifier
                    Return If(identifier.IsMissing, missingTokenPlaceholder, identifier.Text)
                Case SyntaxKind.IncompleteMember
                    Return missingTokenPlaceholder
                Case SyntaxKind.NamespaceBlock
                    Dim nameSyntax = CType(node, NamespaceBlockSyntax).NamespaceStatement.Name
                    If nameSyntax.Kind() = SyntaxKind.GlobalName Then
                        containsGlobalKeyword = True
                        Return Nothing
                    Else
                        Return GetName(nameSyntax, options, containsGlobalKeyword)
                    End If
                Case SyntaxKind.QualifiedName
                    Dim qualified = CType(node, QualifiedNameSyntax)
                    If qualified.Left.Kind() = SyntaxKind.GlobalName Then
                        containsGlobalKeyword = True
                        Return GetName(qualified.Right, options, containsGlobalKeyword) ' don't use the Global prefix if specified
                    Else
                        Return GetName(qualified.Left, options, containsGlobalKeyword) + s_dotToken + GetName(qualified.Right, options, containsGlobalKeyword)
                    End If
            End Select

            Dim name As String = Nothing
            Dim memberDeclaration = TryCast(node, DeclarationStatementSyntax)
            If memberDeclaration IsNot Nothing Then
                Dim nameToken = memberDeclaration.GetNameToken()
                If nameToken <> Nothing Then
                    name = If(nameToken.IsMissing, missingTokenPlaceholder, nameToken.Text)
                    If (options And DisplayNameOptions.IncludeTypeParameters) <> 0 Then
                        Dim pooled = PooledStringBuilder.GetInstance()
                        Dim builder = pooled.Builder
                        builder.Append(name)
                        AppendTypeParameterList(builder, memberDeclaration.GetTypeParameterList())
                        name = pooled.ToStringAndFree()
                    End If
                End If
            End If
            Debug.Assert(name IsNot Nothing, "Unexpected node type " + node.Kind().ToString())
            Return name
        End Function

        Private Shared Sub AppendTypeParameterList(builder As StringBuilder, typeParameterList As TypeParameterListSyntax)
            If typeParameterList IsNot Nothing AndAlso typeParameterList.Parameters.Count > 0 Then
                builder.Append("(Of ")
                builder.Append(typeParameterList.Parameters(0).Identifier.Text)
                For i = 1 To typeParameterList.Parameters.Count - 1
                    builder.Append(", ")
                    builder.Append(typeParameterList.Parameters(i).Identifier.Text)
                Next
                builder.Append(")"c)
            End If
        End Sub

        Private Sub AppendMethodLevelMembers(node As SyntaxNode, list As List(Of SyntaxNode))
            For Each member In node.GetMembers()
                If IsTopLevelNodeWithMembers(member) Then
                    AppendMethodLevelMembers(member, list)
                    Continue For
                End If

                If IsMethodLevelMember(member) Then
                    list.Add(member)
                End If
            Next
        End Sub

        Public Function GetMethodLevelMemberId(root As SyntaxNode, node As SyntaxNode) As Integer Implements ISyntaxFactsService.GetMethodLevelMemberId
            Contract.Requires(root.SyntaxTree Is node.SyntaxTree)

            Dim currentId As Integer = Nothing
            Dim currentNode As SyntaxNode = Nothing
            Contract.ThrowIfFalse(TryGetMethodLevelMember(root, Function(n, i) n Is node, currentId, currentNode))

            Contract.ThrowIfFalse(currentId >= 0)
            CheckMemberId(root, node, currentId)

            Return currentId
        End Function

        Public Function GetMethodLevelMember(root As SyntaxNode, memberId As Integer) As SyntaxNode Implements ISyntaxFactsService.GetMethodLevelMember
            Dim currentId As Integer = Nothing
            Dim currentNode As SyntaxNode = Nothing

            If Not TryGetMethodLevelMember(root, Function(n, i) i = memberId, currentId, currentNode) Then
                Return Nothing
            End If

            Contract.ThrowIfNull(currentNode)
            CheckMemberId(root, currentNode, memberId)

            Return currentNode
        End Function

        Private Function TryGetMethodLevelMember(node As SyntaxNode, predicate As Func(Of SyntaxNode, Integer, Boolean), ByRef currentId As Integer, ByRef currentNode As SyntaxNode) As Boolean
            For Each member In node.GetMembers()
                If TypeOf member Is NamespaceBlockSyntax OrElse
                   TypeOf member Is TypeBlockSyntax OrElse
                   TypeOf member Is EnumBlockSyntax Then
                    If TryGetMethodLevelMember(member, predicate, currentId, currentNode) Then
                        Return True
                    End If

                    Continue For
                End If

                If IsMethodLevelMember(member) Then
                    If predicate(member, currentId) Then
                        currentNode = member
                        Return True
                    End If

                    currentId = currentId + 1
                End If
            Next

            currentNode = Nothing
            Return False
        End Function

        <Conditional("DEBUG")>
        Private Sub CheckMemberId(root As SyntaxNode, node As SyntaxNode, memberId As Integer)
            Dim list = GetMethodLevelMembers(root)
            Dim index = list.IndexOf(node)
            Contract.ThrowIfFalse(index = memberId)
        End Sub

        Public Function GetBindableParent(token As SyntaxToken) As SyntaxNode Implements ISyntaxFactsService.GetBindableParent
            Dim node = token.Parent
            While node IsNot Nothing
                Dim parent = node.Parent

                ' If this node is on the left side of a member access expression, don't ascend
                ' further or we'll end up binding to something else.
                Dim memberAccess = TryCast(parent, MemberAccessExpressionSyntax)
                If memberAccess IsNot Nothing Then
                    If memberAccess.Expression Is node Then
                        Exit While
                    End If
                End If

                ' If this node is on the left side of a qualified name, don't ascend
                ' further or we'll end up binding to something else.
                Dim qualifiedName = TryCast(parent, QualifiedNameSyntax)
                If qualifiedName IsNot Nothing Then
                    If qualifiedName.Left Is node Then
                        Exit While
                    End If
                End If

                ' If this node is the type of an object creation expression, return the
                ' object creation expression.
                Dim objectCreation = TryCast(parent, ObjectCreationExpressionSyntax)
                If objectCreation IsNot Nothing Then
                    If objectCreation.Type Is node Then
                        node = parent
                        Exit While
                    End If
                End If

                ' The inside of an interpolated string is treated as its own token so we
                ' need to force navigation to the parent expression syntax.
                If TypeOf node Is InterpolatedStringTextSyntax AndAlso TypeOf parent Is InterpolatedStringExpressionSyntax Then
                    node = parent
                    Exit While
                End If

                ' If this node is not parented by a name, we're done.
                Dim name = TryCast(parent, NameSyntax)
                If name Is Nothing Then
                    Exit While
                End If

                node = parent
            End While

            Return node
        End Function

        Public Function GetConstructors(root As SyntaxNode, cancellationToken As CancellationToken) As IEnumerable(Of SyntaxNode) Implements ISyntaxFactsService.GetConstructors
            Dim compilationUnit = TryCast(root, CompilationUnitSyntax)
            If compilationUnit Is Nothing Then
                Return SpecializedCollections.EmptyEnumerable(Of SyntaxNode)()
            End If

            Dim constructors = New List(Of SyntaxNode)()
            AppendConstructors(compilationUnit.Members, constructors, cancellationToken)
            Return constructors
        End Function

        Private Sub AppendConstructors(members As SyntaxList(Of StatementSyntax), constructors As List(Of SyntaxNode), cancellationToken As CancellationToken)
            For Each member As StatementSyntax In members
                cancellationToken.ThrowIfCancellationRequested()

                Dim constructor = TryCast(member, ConstructorBlockSyntax)
                If constructor IsNot Nothing Then
                    constructors.Add(constructor)
                    Continue For
                End If

                Dim [namespace] = TryCast(member, NamespaceBlockSyntax)
                If [namespace] IsNot Nothing Then
                    AppendConstructors([namespace].Members, constructors, cancellationToken)
                End If

                Dim [class] = TryCast(member, ClassBlockSyntax)
                If [class] IsNot Nothing Then
                    AppendConstructors([class].Members, constructors, cancellationToken)
                End If

                Dim [struct] = TryCast(member, StructureBlockSyntax)
                If [struct] IsNot Nothing Then
                    AppendConstructors([struct].Members, constructors, cancellationToken)
                End If
            Next
        End Sub

        Public Function GetInactiveRegionSpanAroundPosition(tree As SyntaxTree, position As Integer, cancellationToken As CancellationToken) As TextSpan Implements ISyntaxFactsService.GetInactiveRegionSpanAroundPosition
            Dim trivia = tree.FindTriviaToLeft(position, cancellationToken)
            If trivia.Kind = SyntaxKind.DisabledTextTrivia Then
                Return trivia.FullSpan
            End If

            Return Nothing
        End Function

        Public Function GetNameForArgument(argument As SyntaxNode) As String Implements ISyntaxFactsService.GetNameForArgument
            If TryCast(argument, ArgumentSyntax)?.IsNamed Then
                Return DirectCast(argument, SimpleArgumentSyntax).NameColonEquals.Name.Identifier.ValueText
            End If

            Return String.Empty
        End Function

        Public Function IsLeftSideOfDot(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsLeftSideOfDot
            Return TryCast(node, ExpressionSyntax).IsLeftSideOfDot()
        End Function

        Public Function GetRightSideOfDot(node As SyntaxNode) As SyntaxNode Implements ISyntaxFactsService.GetRightSideOfDot
            Return If(TryCast(node, QualifiedNameSyntax)?.Right,
                      TryCast(node, MemberAccessExpressionSyntax)?.Name)
        End Function

        Public Function IsLeftSideOfAssignment(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsLeftSideOfAssignment
            Return TryCast(node, ExpressionSyntax).IsLeftSideOfAnyAssignStatement
        End Function

        Public Function IsLeftSideOfAnyAssignment(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsLeftSideOfAnyAssignment
            Return TryCast(node, ExpressionSyntax).IsLeftSideOfAnyAssignStatement
        End Function

        Public Function GetRightHandSideOfAssignment(node As SyntaxNode) As SyntaxNode Implements ISyntaxFactsService.GetRightHandSideOfAssignment
            Return TryCast(node, AssignmentStatementSyntax)?.Right
        End Function

        Public Function IsInferredAnonymousObjectMemberDeclarator(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsInferredAnonymousObjectMemberDeclarator
            Return node.IsKind(SyntaxKind.InferredFieldInitializer)
        End Function

        Public Function IsOperandOfIncrementExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsOperandOfIncrementExpression
            Return False
        End Function

        Public Function IsOperandOfIncrementOrDecrementExpression(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsOperandOfIncrementOrDecrementExpression
            Return False
        End Function

        Public Function GetContentsOfInterpolatedString(interpolatedString As SyntaxNode) As SyntaxList(Of SyntaxNode) Implements ISyntaxFactsService.GetContentsOfInterpolatedString
            Return (TryCast(interpolatedString, InterpolatedStringExpressionSyntax)?.Contents).Value
        End Function

        Public Function IsStringLiteral(token As SyntaxToken) As Boolean Implements ISyntaxFactsService.IsStringLiteral
            Return token.IsKind(SyntaxKind.StringLiteralToken)
        End Function

        Public Function GetArgumentsForInvocationExpression(invocationExpression As SyntaxNode) As SeparatedSyntaxList(Of SyntaxNode) Implements ISyntaxFactsService.GetArgumentsForInvocationExpression
            Dim arguments = TryCast(invocationExpression, InvocationExpressionSyntax)?.ArgumentList?.Arguments
            Return If(arguments.HasValue, arguments.Value, Nothing)
        End Function

        Public Function ConvertToSingleLine(node As SyntaxNode, Optional useElasticTrivia As Boolean = False) As SyntaxNode Implements ISyntaxFactsService.ConvertToSingleLine
            Return node.ConvertToSingleLine(useElasticTrivia)
        End Function

        Public Function IsDocumentationComment(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsDocumentationComment
            Return node.IsKind(SyntaxKind.DocumentationCommentTrivia)
        End Function

        Public Function IsUsingOrExternOrImport(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsUsingOrExternOrImport
            Return node.IsKind(SyntaxKind.ImportsStatement)
        End Function

        Public Function IsGlobalAttribute(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsGlobalAttribute
            If node.IsKind(SyntaxKind.Attribute) Then
                Dim attributeNode = CType(node, AttributeSyntax)
                If attributeNode.Target IsNot Nothing Then
                    Return attributeNode.Target.AttributeModifier.IsKind(SyntaxKind.AssemblyKeyword)
                End If
            End If

            Return False
        End Function

        Public Function IsDeclaration(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsDeclaration
            ' From the Visual Basic language spec:
            ' NamespaceMemberDeclaration  :=
            '    NamespaceDeclaration  |
            '    TypeDeclaration
            ' TypeDeclaration  ::=
            '    ModuleDeclaration  |
            '    NonModuleDeclaration
            ' NonModuleDeclaration  ::=
            '    EnumDeclaration  |
            '    StructureDeclaration  |
            '    InterfaceDeclaration  |
            '    ClassDeclaration  |
            '    DelegateDeclaration
            ' ClassMemberDeclaration  ::=
            '    NonModuleDeclaration  |
            '    EventMemberDeclaration  |
            '    VariableMemberDeclaration  |
            '    ConstantMemberDeclaration  |
            '    MethodMemberDeclaration  |
            '    PropertyMemberDeclaration  |
            '    ConstructorMemberDeclaration  |
            '    OperatorDeclaration
            Select Case node.Kind()
                ' Because fields declarations can define multiple symbols "Public a, b As Integer" 
                ' We want to get the VariableDeclarator node inside the field declaration to print out the symbol for the name.
                Case SyntaxKind.VariableDeclarator
                    If (node.Parent.IsKind(SyntaxKind.FieldDeclaration)) Then
                        Return True
                    End If
                    Return False

                Case SyntaxKind.NamespaceStatement,
                     SyntaxKind.NamespaceBlock,
                     SyntaxKind.ModuleStatement,
                     SyntaxKind.ModuleBlock,
                     SyntaxKind.EnumStatement,
                     SyntaxKind.EnumBlock,
                     SyntaxKind.StructureStatement,
                     SyntaxKind.StructureBlock,
                     SyntaxKind.InterfaceStatement,
                     SyntaxKind.InterfaceBlock,
                     SyntaxKind.ClassStatement,
                     SyntaxKind.ClassBlock,
                     SyntaxKind.DelegateFunctionStatement,
                     SyntaxKind.DelegateSubStatement,
                     SyntaxKind.EventStatement,
                     SyntaxKind.EventBlock,
                     SyntaxKind.AddHandlerAccessorBlock,
                     SyntaxKind.RemoveHandlerAccessorBlock,
                     SyntaxKind.FieldDeclaration,
                     SyntaxKind.SubStatement,
                     SyntaxKind.SubBlock,
                     SyntaxKind.FunctionStatement,
                     SyntaxKind.FunctionBlock,
                     SyntaxKind.PropertyStatement,
                     SyntaxKind.PropertyBlock,
                     SyntaxKind.GetAccessorBlock,
                     SyntaxKind.SetAccessorBlock,
                     SyntaxKind.SubNewStatement,
                     SyntaxKind.ConstructorBlock,
                     SyntaxKind.OperatorStatement,
                     SyntaxKind.OperatorBlock
                    Return True
            End Select

            Return False
        End Function

        Public Sub AddFirstMissingCloseBrace(root As SyntaxNode, contextNode As SyntaxNode, ByRef newRoot As SyntaxNode, ByRef newContextNode As SyntaxNode) Implements ISyntaxFactsService.AddFirstMissingCloseBrace
            ' Nothing to be done.  VB doesn't have close braces
            newRoot = root
            newContextNode = contextNode
        End Sub
    End Class
End Namespace