private bool GetSpeculativeSemanticModelForMethodBody(SyntaxTreeSemanticModel parentModel, int position, BlockSyntax body, out SemanticModel speculativeModel)
        {
            position = CheckAndAdjustPosition(position);

            var methodSymbol = (MethodSymbol)this.MemberSymbol;

            // Strip off ExecutableCodeBinder (see ctor).
            Binder binder = this.RootBinder;

            do
            {
                if (binder is ExecutableCodeBinder)
                {
                    binder = binder.Next;
                    break;
                }

                binder = binder.Next;
            }
            while (binder != null);

            Debug.Assert(binder != null);

            var executablebinder = new ExecutableCodeBinder(body, methodSymbol, binder ?? this.RootBinder);
            var blockBinder = executablebinder.GetBinder(body).WithAdditionalFlags(GetSemanticModelBinderFlags());
            speculativeModel = CreateSpeculative(parentModel, methodSymbol, body, blockBinder, position);
            return true;
        }

        /// <summary>
        /// Creates a speculative AttributeSemanticModel that allows asking semantic questions about an attribute node that did not appear in the original source code.
        /// </summary>
        public static AttributeSemanticModel CreateSpeculative(SyntaxTreeSemanticModel parentSemanticModel, AttributeSyntax syntax, NamedTypeSymbol attributeType, AliasSymbol aliasOpt, Binder rootBinder, int position)
        {
            Debug.Assert(parentSemanticModel != null);
            Debug.Assert(rootBinder != null);
            Debug.Assert(rootBinder.IsSemanticModelBinder);

            return new AttributeSemanticModel(parentSemanticModel.Compilation, syntax, attributeType, aliasOpt, rootBinder, parentSemanticModel, position);
        }

 private MethodBodySemanticModel(CSharpCompilation compilation, Symbol owner, Binder rootBinder, CSharpSyntaxNode syntax, SyntaxTreeSemanticModel parentSemanticModelOpt = null, int speculatedPosition = 0)
     : base(compilation, syntax, owner, rootBinder, parentSemanticModelOpt, speculatedPosition)
 {
     Debug.Assert((object)owner != null);
     Debug.Assert(owner.Kind == SymbolKind.Method);
     Debug.Assert(syntax != null);
     Debug.Assert(owner.ContainingType.IsScriptClass || syntax.Kind != SyntaxKind.CompilationUnit);
 }

 // create a SemanticModel for:
 // (a) A true field initializer (field = value) of a named type (incl. Enums) OR
 // (b) A constructor initializer (": this(...)" or ": base(...)") OR
 // (c) A parameter default value
 private InitializerSemanticModel(CSharpCompilation compilation,
                              CSharpSyntaxNode syntax,
                              Symbol symbol,
                              Binder rootBinder,
                              SyntaxTreeSemanticModel parentSemanticModelOpt = null,
                              int speculatedPosition = 0) :
     base(compilation, syntax, symbol, rootBinder, parentSemanticModelOpt, speculatedPosition)
 {
 }

        /// <summary>
        /// Creates a speculative SemanticModel for a method body that did not appear in the original source code.
        /// </summary>
        internal static MethodBodySemanticModel CreateSpeculative(SyntaxTreeSemanticModel parentSemanticModel, MethodSymbol owner, StatementSyntax syntax, Binder rootBinder, int position)
        {
            Debug.Assert(parentSemanticModel != null);
            Debug.Assert(syntax != null);
            Debug.Assert(rootBinder != null);
            Debug.Assert(rootBinder.IsSemanticModelBinder);

            return new MethodBodySemanticModel(parentSemanticModel.Compilation, owner, rootBinder, syntax, parentSemanticModel, position);
        }

        private bool GetSpeculativeSemanticModelForMethodBody(SyntaxTreeSemanticModel parentModel, int position, BlockSyntax body, out SemanticModel speculativeModel)
        {
            position = CheckAndAdjustPosition(position);

            var methodSymbol = (MethodSymbol)this.MemberSymbol;
            var executablebinder = new ExecutableCodeBinder(body, methodSymbol, this.rootBinder.Next); // Strip off ExecutableCodeBinder (see ctor).
            var blockBinder = executablebinder.GetBinder(body).WithAdditionalFlags(BinderFlags.SemanticModel);
            speculativeModel = CreateSpeculative(parentModel, methodSymbol, body, blockBinder, position);
            return true;
        }

        /// <summary>
        /// Creates a speculative SemanticModel for an initializer node (field initializer, constructor initializer, or parameter default value)
        /// that did not appear in the original source code.
        /// </summary>
        internal static InitializerSemanticModel CreateSpeculative(SyntaxTreeSemanticModel parentSemanticModel, Symbol owner, CSharpSyntaxNode syntax, Binder rootBinder, int position)
        {
            Debug.Assert(parentSemanticModel != null);
            Debug.Assert(syntax != null);
            Debug.Assert(syntax.IsKind(SyntaxKind.EqualsValueClause) || syntax.IsKind(SyntaxKind.ThisConstructorInitializer) || syntax.IsKind(SyntaxKind.BaseConstructorInitializer));
            Debug.Assert(rootBinder != null);
            Debug.Assert(rootBinder.IsSemanticModelBinder);

            return new InitializerSemanticModel(parentSemanticModel.Compilation, syntax, owner, rootBinder, parentSemanticModel, position);
        }

        protected MemberSemanticModel(CSharpCompilation compilation, CSharpSyntaxNode root, Symbol memberSymbol, Binder rootBinder, SyntaxTreeSemanticModel parentSemanticModelOpt, int speculatedPosition)
        {
            Debug.Assert(compilation != null);
            Debug.Assert(root != null);
            Debug.Assert((object)memberSymbol != null);
            Debug.Assert(parentSemanticModelOpt == null || !parentSemanticModelOpt.IsSpeculativeSemanticModel, CSharpResources.ChainingSpeculativeModelIsNotSupported);

            this.compilation = compilation;
            this.root = root;
            this.memberSymbol = memberSymbol;
            this.RootBinder = rootBinder.WithAdditionalFlags(BinderFlags.SemanticModel);
            this.parentSemanticModelOpt = parentSemanticModelOpt;
            this.speculatedPosition = speculatedPosition;
        }

        internal override bool TryGetSpeculativeSemanticModelCore(SyntaxTreeSemanticModel parentModel, int position, StatementSyntax statement, out SemanticModel speculativeModel)
        {
            position = CheckAndAdjustPosition(position);

            var binder = this.GetEnclosingBinder(position);
            if (binder == null)
            {
                speculativeModel = null;
                return false;
            }

            var methodSymbol = (MethodSymbol)this.MemberSymbol;
            binder = new ExecutableCodeBinder(statement, methodSymbol, binder);

            // local declaration statements need to be wrapped in a block so the local gets seen 
            if (!statement.IsKind(SyntaxKind.Block))
            {
                binder = new BlockBinder(methodSymbol, binder, new SyntaxList<StatementSyntax>(statement));
            }

            speculativeModel = CreateSpeculative(parentModel, methodSymbol, statement, binder, position);
            return true;
        }

        internal override bool TryGetSpeculativeSemanticModelCore(SyntaxTreeSemanticModel parentModel, int position, ArrowExpressionClauseSyntax expressionBody, out SemanticModel speculativeModel)
        {
            position = CheckAndAdjustPosition(position);

            var model = this.GetMemberModel(position);
            if (model != null)
            {
                return model.TryGetSpeculativeSemanticModelCore(parentModel, position, expressionBody, out speculativeModel);
            }

            speculativeModel = null;
            return false;
        }

        internal sealed override bool TryGetSpeculativeSemanticModelCore(SyntaxTreeSemanticModel parentModel, int position, TypeSyntax type, SpeculativeBindingOption bindingOption, out SemanticModel speculativeModel)
        {
            var expression = SyntaxFactory.GetStandaloneExpression(type);

            var binder = this.GetSpeculativeBinder(position, expression, bindingOption);
            if (binder != null)
            {
                speculativeModel = new SpeculativeMemberSemanticModel(parentModel, _memberSymbol, type, binder, position);
                return true;
            }

            speculativeModel = null;
            return false;
        }

        internal sealed override bool TryGetSpeculativeSemanticModelForMethodBodyCore(SyntaxTreeSemanticModel parentModel, int position, AccessorDeclarationSyntax accessor, out SemanticModel speculativeModel)
        {
            position = CheckAndAdjustPosition(position);

            var model = this.GetMemberModel(position);
            if (model != null)
            {
                return model.TryGetSpeculativeSemanticModelForMethodBodyCore(parentModel, position, accessor, out speculativeModel);
            }

            speculativeModel = null;
            return false;
        }

 internal override bool TryGetSpeculativeSemanticModelForMethodBodyCore(SyntaxTreeSemanticModel parentModel, int position, AccessorDeclarationSyntax accessor, out SemanticModel speculativeModel)
 {
     speculativeModel = null;
     return false;
 }

 internal override bool TryGetSpeculativeSemanticModelForMethodBodyCore(SyntaxTreeSemanticModel parentModel, int position, AccessorDeclarationSyntax accessor, out SemanticModel speculativeModel)
 {
     return GetSpeculativeSemanticModelForMethodBody(parentModel, position, accessor.Body, out speculativeModel);
 }

        private bool TryGetSpeculativeSemanticModelCore(SyntaxTreeSemanticModel parentModel, int position, CSharpSyntaxNode initializer, out SemanticModel speculativeModel)
        {
            Debug.Assert(initializer is EqualsValueClauseSyntax || initializer is ConstructorInitializerSyntax);

            var binder = this.GetEnclosingBinder(position);
            if (binder == null)
            {
                speculativeModel = null;
                return false;
            }

            speculativeModel = CreateSpeculative(parentModel, this.MemberSymbol, initializer, binder, position);
            return true;
        }