factoryPublic.ts

namespace ts {
    function createSynthesizedNode(kind: SyntaxKind): Node {
        const node = createNode(kind, -1, -1);
        node.flags |= NodeFlags.Synthesized;
        return node;
    }

    /* @internal */
    export function updateNode<T extends Node>(updated: T, original: T): T {
        if (updated !== original) {
            setOriginalNode(updated, original);
            setTextRange(updated, original);
            aggregateTransformFlags(updated);
        }
        return updated;
    }

    /* @internal */ export function createNodeArray<T extends Node>(elements?: T[], hasTrailingComma?: boolean): MutableNodeArray<T>;
    export function createNodeArray<T extends Node>(elements?: readonly T[], hasTrailingComma?: boolean): NodeArray<T>;
    /**
     * Make `elements` into a `NodeArray<T>`. If `elements` is `undefined`, returns an empty `NodeArray<T>`.
     */
    export function createNodeArray<T extends Node>(elements?: readonly T[], hasTrailingComma?: boolean): NodeArray<T> {
        if (!elements || elements === emptyArray) {
            elements = [];
        }
        else if (isNodeArray(elements)) {
            return elements;
        }

        const array = <NodeArray<T>>elements;
        array.pos = -1;
        array.end = -1;
        array.hasTrailingComma = hasTrailingComma;
        return array;
    }

    /**
     * Creates a shallow, memberwise clone of a node with no source map location.
     */
    /* @internal */
    export function getSynthesizedClone<T extends Node>(node: T): T {
        // We don't use "clone" from core.ts here, as we need to preserve the prototype chain of
        // the original node. We also need to exclude specific properties and only include own-
        // properties (to skip members already defined on the shared prototype).

        if (node === undefined) {
            return node;
        }

        const clone = <T>createSynthesizedNode(node.kind);
        clone.flags |= node.flags;
        setOriginalNode(clone, node);

        for (const key in node) {
            if (clone.hasOwnProperty(key) || !node.hasOwnProperty(key)) {
                continue;
            }

            (<any>clone)[key] = (<any>node)[key];
        }

        return clone;
    }

    // Literals

    /* @internal */ export function createLiteral(value: string | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier, isSingleQuote: boolean): StringLiteral; // eslint-disable-line @typescript-eslint/unified-signatures
    /* @internal */ export function createLiteral(value: string | number, isSingleQuote: boolean): StringLiteral | NumericLiteral;
    /** If a node is passed, creates a string literal whose source text is read from a source node during emit. */
    export function createLiteral(value: string | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier): StringLiteral;
    export function createLiteral(value: number | PseudoBigInt): NumericLiteral;
    export function createLiteral(value: boolean): BooleanLiteral;
    export function createLiteral(value: string | number | PseudoBigInt | boolean): PrimaryExpression;
    export function createLiteral(value: string | number | PseudoBigInt | boolean | StringLiteral | NoSubstitutionTemplateLiteral | NumericLiteral | Identifier, isSingleQuote?: boolean): PrimaryExpression {
        if (typeof value === "number") {
            return createNumericLiteral(value + "");
        }
        // eslint-disable-next-line no-in-operator
        if (typeof value === "object" && "base10Value" in value) { // PseudoBigInt
            return createBigIntLiteral(pseudoBigIntToString(value) + "n");
        }
        if (typeof value === "boolean") {
            return value ? createTrue() : createFalse();
        }
        if (isString(value)) {
            const res = createStringLiteral(value);
            if (isSingleQuote) res.singleQuote = true;
            return res;
        }
        return createLiteralFromNode(value);
    }

    export function createNumericLiteral(value: string, numericLiteralFlags: TokenFlags = TokenFlags.None): NumericLiteral {
        const node = <NumericLiteral>createSynthesizedNode(SyntaxKind.NumericLiteral);
        node.text = value;
        node.numericLiteralFlags = numericLiteralFlags;
        return node;
    }

    export function createBigIntLiteral(value: string): BigIntLiteral {
        const node = <BigIntLiteral>createSynthesizedNode(SyntaxKind.BigIntLiteral);
        node.text = value;
        return node;
    }

    export function createStringLiteral(text: string): StringLiteral {
        const node = <StringLiteral>createSynthesizedNode(SyntaxKind.StringLiteral);
        node.text = text;
        return node;
    }

    export function createRegularExpressionLiteral(text: string): RegularExpressionLiteral {
        const node = <RegularExpressionLiteral>createSynthesizedNode(SyntaxKind.RegularExpressionLiteral);
        node.text = text;
        return node;
    }

    function createLiteralFromNode(sourceNode: Exclude<PropertyNameLiteral, PrivateIdentifier>): StringLiteral {
        const node = createStringLiteral(getTextOfIdentifierOrLiteral(sourceNode));
        node.textSourceNode = sourceNode;
        return node;
    }


    // Identifiers

    export function createIdentifier(text: string): Identifier;
    /* @internal */
    export function createIdentifier(text: string, typeArguments: readonly (TypeNode | TypeParameterDeclaration)[] | undefined): Identifier; // eslint-disable-line @typescript-eslint/unified-signatures
    export function createIdentifier(text: string, typeArguments?: readonly (TypeNode | TypeParameterDeclaration)[]): Identifier {
        const node = <Identifier>createSynthesizedNode(SyntaxKind.Identifier);
        node.escapedText = escapeLeadingUnderscores(text);
        node.originalKeywordKind = text ? stringToToken(text) : SyntaxKind.Unknown;
        node.autoGenerateFlags = GeneratedIdentifierFlags.None;
        node.autoGenerateId = 0;
        if (typeArguments) {
            node.typeArguments = createNodeArray(typeArguments as readonly TypeNode[]);
        }
        return node;
    }

    export function updateIdentifier(node: Identifier): Identifier;
    /* @internal */
    export function updateIdentifier(node: Identifier, typeArguments: NodeArray<TypeNode | TypeParameterDeclaration> | undefined): Identifier; // eslint-disable-line @typescript-eslint/unified-signatures
    export function updateIdentifier(node: Identifier, typeArguments?: NodeArray<TypeNode | TypeParameterDeclaration> | undefined): Identifier {
        return node.typeArguments !== typeArguments
            ? updateNode(createIdentifier(idText(node), typeArguments), node)
            : node;
    }

    let nextAutoGenerateId = 0;

    /** Create a unique temporary variable. */
    export function createTempVariable(recordTempVariable: ((node: Identifier) => void) | undefined): Identifier;
    /* @internal */ export function createTempVariable(recordTempVariable: ((node: Identifier) => void) | undefined, reservedInNestedScopes: boolean): GeneratedIdentifier;
    export function createTempVariable(recordTempVariable: ((node: Identifier) => void) | undefined, reservedInNestedScopes?: boolean): GeneratedIdentifier {
        const name = createIdentifier("") as GeneratedIdentifier;
        name.autoGenerateFlags = GeneratedIdentifierFlags.Auto;
        name.autoGenerateId = nextAutoGenerateId;
        nextAutoGenerateId++;
        if (recordTempVariable) {
            recordTempVariable(name);
        }
        if (reservedInNestedScopes) {
            name.autoGenerateFlags |= GeneratedIdentifierFlags.ReservedInNestedScopes;
        }
        return name;
    }

    /** Create a unique temporary variable for use in a loop. */
    export function createLoopVariable(): Identifier {
        const name = createIdentifier("");
        name.autoGenerateFlags = GeneratedIdentifierFlags.Loop;
        name.autoGenerateId = nextAutoGenerateId;
        nextAutoGenerateId++;
        return name;
    }

    /** Create a unique name based on the supplied text. */
    export function createUniqueName(text: string): Identifier {
        const name = createIdentifier(text);
        name.autoGenerateFlags = GeneratedIdentifierFlags.Unique;
        name.autoGenerateId = nextAutoGenerateId;
        nextAutoGenerateId++;
        return name;
    }

    /* @internal */ export function createOptimisticUniqueName(text: string): GeneratedIdentifier;
    /** Create a unique name based on the supplied text. */
    export function createOptimisticUniqueName(text: string): Identifier;
    export function createOptimisticUniqueName(text: string): GeneratedIdentifier {
        const name = createIdentifier(text) as GeneratedIdentifier;
        name.autoGenerateFlags = GeneratedIdentifierFlags.Unique | GeneratedIdentifierFlags.Optimistic;
        name.autoGenerateId = nextAutoGenerateId;
        nextAutoGenerateId++;
        return name;
    }

    /** Create a unique name based on the supplied text. This does not consider names injected by the transformer. */
    export function createFileLevelUniqueName(text: string): Identifier {
        const name = createOptimisticUniqueName(text);
        name.autoGenerateFlags |= GeneratedIdentifierFlags.FileLevel;
        return name;
    }

    /** Create a unique name generated for a node. */
    export function getGeneratedNameForNode(node: Node | undefined): Identifier;
    /* @internal */ export function getGeneratedNameForNode(node: Node | undefined, flags: GeneratedIdentifierFlags): Identifier; // eslint-disable-line @typescript-eslint/unified-signatures
    export function getGeneratedNameForNode(node: Node | undefined, flags?: GeneratedIdentifierFlags): Identifier {
        const name = createIdentifier(node && isIdentifier(node) ? idText(node) : "");
        name.autoGenerateFlags = GeneratedIdentifierFlags.Node | flags!;
        name.autoGenerateId = nextAutoGenerateId;
        name.original = node;
        nextAutoGenerateId++;
        return name;
    }

    // Private Identifiers
    export function createPrivateIdentifier(text: string): PrivateIdentifier {
        if (text[0] !== "#") {
            Debug.fail("First character of private identifier must be #: " + text);
        }
        const node = createSynthesizedNode(SyntaxKind.PrivateIdentifier) as PrivateIdentifier;
        node.escapedText = escapeLeadingUnderscores(text);
        return node;
    }

    // Punctuation

    export function createToken<TKind extends SyntaxKind>(token: TKind) {
        return <Token<TKind>>createSynthesizedNode(token);
    }

    // Reserved words

    export function createSuper() {
        return <SuperExpression>createSynthesizedNode(SyntaxKind.SuperKeyword);
    }

    export function createThis() {
        return <ThisExpression & Token<SyntaxKind.ThisKeyword>>createSynthesizedNode(SyntaxKind.ThisKeyword);
    }

    export function createNull() {
        return <NullLiteral & Token<SyntaxKind.NullKeyword>>createSynthesizedNode(SyntaxKind.NullKeyword);
    }

    export function createTrue() {
        return <BooleanLiteral & Token<SyntaxKind.TrueKeyword>>createSynthesizedNode(SyntaxKind.TrueKeyword);
    }

    export function createFalse() {
        return <BooleanLiteral & Token<SyntaxKind.FalseKeyword>>createSynthesizedNode(SyntaxKind.FalseKeyword);
    }

    // Modifiers

    export function createModifier<T extends Modifier["kind"]>(kind: T): Token<T> {
        return createToken(kind);
    }

    export function createModifiersFromModifierFlags(flags: ModifierFlags) {
        const result: Modifier[] = [];
        if (flags & ModifierFlags.Export) { result.push(createModifier(SyntaxKind.ExportKeyword)); }
        if (flags & ModifierFlags.Ambient) { result.push(createModifier(SyntaxKind.DeclareKeyword)); }
        if (flags & ModifierFlags.Default) { result.push(createModifier(SyntaxKind.DefaultKeyword)); }
        if (flags & ModifierFlags.Const) { result.push(createModifier(SyntaxKind.ConstKeyword)); }
        if (flags & ModifierFlags.Public) { result.push(createModifier(SyntaxKind.PublicKeyword)); }
        if (flags & ModifierFlags.Private) { result.push(createModifier(SyntaxKind.PrivateKeyword)); }
        if (flags & ModifierFlags.Protected) { result.push(createModifier(SyntaxKind.ProtectedKeyword)); }
        if (flags & ModifierFlags.Abstract) { result.push(createModifier(SyntaxKind.AbstractKeyword)); }
        if (flags & ModifierFlags.Static) { result.push(createModifier(SyntaxKind.StaticKeyword)); }
        if (flags & ModifierFlags.Readonly) { result.push(createModifier(SyntaxKind.ReadonlyKeyword)); }
        if (flags & ModifierFlags.Async) { result.push(createModifier(SyntaxKind.AsyncKeyword)); }
        return result;
    }

    // Names

    export function createQualifiedName(left: EntityName, right: string | Identifier) {
        const node = <QualifiedName>createSynthesizedNode(SyntaxKind.QualifiedName);
        node.left = left;
        node.right = asName(right);
        return node;
    }

    export function updateQualifiedName(node: QualifiedName, left: EntityName, right: Identifier) {
        return node.left !== left
            || node.right !== right
            ? updateNode(createQualifiedName(left, right), node)
            : node;
    }

    function parenthesizeForComputedName(expression: Expression): Expression {
        return isCommaSequence(expression)
            ? createParen(expression)
            : expression;
    }

    export function createComputedPropertyName(expression: Expression) {
        const node = <ComputedPropertyName>createSynthesizedNode(SyntaxKind.ComputedPropertyName);
        node.expression = parenthesizeForComputedName(expression);
        return node;
    }

    export function updateComputedPropertyName(node: ComputedPropertyName, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createComputedPropertyName(expression), node)
            : node;
    }

    // Signature elements

    export function createTypeParameterDeclaration(name: string | Identifier, constraint?: TypeNode, defaultType?: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.TypeParameter) as TypeParameterDeclaration;
        node.name = asName(name);
        node.constraint = constraint;
        node.default = defaultType;
        return node;
    }

    export function updateTypeParameterDeclaration(node: TypeParameterDeclaration, name: Identifier, constraint: TypeNode | undefined, defaultType: TypeNode | undefined) {
        return node.name !== name
            || node.constraint !== constraint
            || node.default !== defaultType
            ? updateNode(createTypeParameterDeclaration(name, constraint, defaultType), node)
            : node;
    }

    export function createParameter(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        dotDotDotToken: DotDotDotToken | undefined,
        name: string | BindingName,
        questionToken?: QuestionToken,
        type?: TypeNode,
        initializer?: Expression) {
        const node = <ParameterDeclaration>createSynthesizedNode(SyntaxKind.Parameter);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.dotDotDotToken = dotDotDotToken;
        node.name = asName(name);
        node.questionToken = questionToken;
        node.type = type;
        node.initializer = initializer ? parenthesizeExpressionForList(initializer) : undefined;
        return node;
    }

    export function updateParameter(
        node: ParameterDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        dotDotDotToken: DotDotDotToken | undefined,
        name: string | BindingName,
        questionToken: QuestionToken | undefined,
        type: TypeNode | undefined,
        initializer: Expression | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.dotDotDotToken !== dotDotDotToken
            || node.name !== name
            || node.questionToken !== questionToken
            || node.type !== type
            || node.initializer !== initializer
            ? updateNode(createParameter(decorators, modifiers, dotDotDotToken, name, questionToken, type, initializer), node)
            : node;
    }

    export function createDecorator(expression: Expression) {
        const node = <Decorator>createSynthesizedNode(SyntaxKind.Decorator);
        node.expression = parenthesizeForAccess(expression);
        return node;
    }

    export function updateDecorator(node: Decorator, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createDecorator(expression), node)
            : node;
    }


    // Type Elements

    export function createPropertySignature(
        modifiers: readonly Modifier[] | undefined,
        name: PropertyName | string,
        questionToken: QuestionToken | undefined,
        type: TypeNode | undefined,
        initializer: Expression | undefined): PropertySignature {
        const node = createSynthesizedNode(SyntaxKind.PropertySignature) as PropertySignature;
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.questionToken = questionToken;
        node.type = type;
        node.initializer = initializer;
        return node;
    }

    export function updatePropertySignature(
        node: PropertySignature,
        modifiers: readonly Modifier[] | undefined,
        name: PropertyName,
        questionToken: QuestionToken | undefined,
        type: TypeNode | undefined,
        initializer: Expression | undefined) {
        return node.modifiers !== modifiers
            || node.name !== name
            || node.questionToken !== questionToken
            || node.type !== type
            || node.initializer !== initializer
            ? updateNode(createPropertySignature(modifiers, name, questionToken, type, initializer), node)
            : node;
    }

    export function createProperty(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | PropertyName,
        questionOrExclamationToken: QuestionToken | ExclamationToken | undefined,
        type: TypeNode | undefined,
        initializer: Expression | undefined) {
        const node = <PropertyDeclaration>createSynthesizedNode(SyntaxKind.PropertyDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.questionToken = questionOrExclamationToken !== undefined && questionOrExclamationToken.kind === SyntaxKind.QuestionToken ? questionOrExclamationToken : undefined;
        node.exclamationToken = questionOrExclamationToken !== undefined && questionOrExclamationToken.kind === SyntaxKind.ExclamationToken ? questionOrExclamationToken : undefined;
        node.type = type;
        node.initializer = initializer;
        return node;
    }

    export function updateProperty(
        node: PropertyDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | PropertyName,
        questionOrExclamationToken: QuestionToken | ExclamationToken | undefined,
        type: TypeNode | undefined,
        initializer: Expression | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.questionToken !== (questionOrExclamationToken !== undefined && questionOrExclamationToken.kind === SyntaxKind.QuestionToken ? questionOrExclamationToken : undefined)
            || node.exclamationToken !== (questionOrExclamationToken !== undefined && questionOrExclamationToken.kind === SyntaxKind.ExclamationToken ? questionOrExclamationToken : undefined)
            || node.type !== type
            || node.initializer !== initializer
            ? updateNode(createProperty(decorators, modifiers, name, questionOrExclamationToken, type, initializer), node)
            : node;
    }

    export function createMethodSignature(
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        name: string | PropertyName,
        questionToken: QuestionToken | undefined) {
        const node = createSignatureDeclaration(SyntaxKind.MethodSignature, typeParameters, parameters, type) as MethodSignature;
        node.name = asName(name);
        node.questionToken = questionToken;
        return node;
    }

    export function updateMethodSignature(node: MethodSignature, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined, name: PropertyName, questionToken: QuestionToken | undefined) {
        return node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            || node.name !== name
            || node.questionToken !== questionToken
            ? updateNode(createMethodSignature(typeParameters, parameters, type, name, questionToken), node)
            : node;
    }

    export function createMethod(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: string | PropertyName,
        questionToken: QuestionToken | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        const node = <MethodDeclaration>createSynthesizedNode(SyntaxKind.MethodDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.asteriskToken = asteriskToken;
        node.name = asName(name);
        node.questionToken = questionToken;
        node.typeParameters = asNodeArray(typeParameters);
        node.parameters = createNodeArray(parameters);
        node.type = type;
        node.body = body;
        return node;
    }

    function createMethodCall(object: Expression, methodName: string | Identifier, argumentsList: readonly Expression[]) {
        return createCall(
            createPropertyAccess(object, asName(methodName)),
            /*typeArguments*/ undefined,
            argumentsList
        );
    }

    function createGlobalMethodCall(globalObjectName: string, methodName: string, argumentsList: readonly Expression[]) {
        return createMethodCall(createIdentifier(globalObjectName), methodName, argumentsList);
    }

    /* @internal */
    export function createObjectDefinePropertyCall(target: Expression, propertyName: string | Expression, attributes: Expression) {
        return createGlobalMethodCall("Object", "defineProperty", [target, asExpression(propertyName), attributes]);
    }

    function tryAddPropertyAssignment(properties: Push<PropertyAssignment>, propertyName: string, expression: Expression | undefined) {
        if (expression) {
            properties.push(createPropertyAssignment(propertyName, expression));
            return true;
        }
        return false;
    }

    /* @internal */
    export function createPropertyDescriptor(attributes: PropertyDescriptorAttributes, singleLine?: boolean) {
        const properties: PropertyAssignment[] = [];
        tryAddPropertyAssignment(properties, "enumerable", asExpression(attributes.enumerable));
        tryAddPropertyAssignment(properties, "configurable", asExpression(attributes.configurable));

        let isData = tryAddPropertyAssignment(properties, "writable", asExpression(attributes.writable));
        isData = tryAddPropertyAssignment(properties, "value", attributes.value) || isData;

        let isAccessor = tryAddPropertyAssignment(properties, "get", attributes.get);
        isAccessor = tryAddPropertyAssignment(properties, "set", attributes.set) || isAccessor;

        Debug.assert(!(isData && isAccessor), "A PropertyDescriptor may not be both an accessor descriptor and a data descriptor.");
        return createObjectLiteral(properties, !singleLine);
    }

    export function updateMethod(
        node: MethodDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: PropertyName,
        questionToken: QuestionToken | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.asteriskToken !== asteriskToken
            || node.name !== name
            || node.questionToken !== questionToken
            || node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            || node.body !== body
            ? updateNode(createMethod(decorators, modifiers, asteriskToken, name, questionToken, typeParameters, parameters, type, body), node)
            : node;
    }

    export function createConstructor(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, parameters: readonly ParameterDeclaration[], body: Block | undefined) {
        const node = <ConstructorDeclaration>createSynthesizedNode(SyntaxKind.Constructor);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.typeParameters = undefined;
        node.parameters = createNodeArray(parameters);
        node.type = undefined;
        node.body = body;
        return node;
    }

    export function updateConstructor(
        node: ConstructorDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        parameters: readonly ParameterDeclaration[],
        body: Block | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.parameters !== parameters
            || node.body !== body
            ? updateNode(createConstructor(decorators, modifiers, parameters, body), node)
            : node;
    }

    export function createGetAccessor(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | PropertyName,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        const node = <GetAccessorDeclaration>createSynthesizedNode(SyntaxKind.GetAccessor);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = undefined;
        node.parameters = createNodeArray(parameters);
        node.type = type;
        node.body = body;
        return node;
    }

    export function updateGetAccessor(
        node: GetAccessorDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: PropertyName,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.parameters !== parameters
            || node.type !== type
            || node.body !== body
            ? updateNode(createGetAccessor(decorators, modifiers, name, parameters, type, body), node)
            : node;
    }

    export function createSetAccessor(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | PropertyName,
        parameters: readonly ParameterDeclaration[],
        body: Block | undefined) {
        const node = <SetAccessorDeclaration>createSynthesizedNode(SyntaxKind.SetAccessor);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = undefined;
        node.parameters = createNodeArray(parameters);
        node.body = body;
        return node;
    }

    export function updateSetAccessor(
        node: SetAccessorDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: PropertyName,
        parameters: readonly ParameterDeclaration[],
        body: Block | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.parameters !== parameters
            || node.body !== body
            ? updateNode(createSetAccessor(decorators, modifiers, name, parameters, body), node)
            : node;
    }

    export function createCallSignature(typeParameters: readonly TypeParameterDeclaration[] | undefined, parameters: readonly ParameterDeclaration[], type: TypeNode | undefined) {
        return createSignatureDeclaration(SyntaxKind.CallSignature, typeParameters, parameters, type) as CallSignatureDeclaration;
    }

    export function updateCallSignature(node: CallSignatureDeclaration, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined) {
        return updateSignatureDeclaration(node, typeParameters, parameters, type);
    }

    export function createConstructSignature(typeParameters: readonly TypeParameterDeclaration[] | undefined, parameters: readonly ParameterDeclaration[], type: TypeNode | undefined) {
        return createSignatureDeclaration(SyntaxKind.ConstructSignature, typeParameters, parameters, type) as ConstructSignatureDeclaration;
    }

    export function updateConstructSignature(node: ConstructSignatureDeclaration, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined) {
        return updateSignatureDeclaration(node, typeParameters, parameters, type);
    }

    export function createIndexSignature(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode): IndexSignatureDeclaration {
        const node = createSynthesizedNode(SyntaxKind.IndexSignature) as IndexSignatureDeclaration;
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.parameters = createNodeArray(parameters);
        node.type = type;
        return node;
    }

    export function updateIndexSignature(
        node: IndexSignatureDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode) {
        return node.parameters !== parameters
            || node.type !== type
            || node.decorators !== decorators
            || node.modifiers !== modifiers
            ? updateNode(createIndexSignature(decorators, modifiers, parameters, type), node)
            : node;
    }

    /* @internal */
    export function createSignatureDeclaration(kind: SyntaxKind, typeParameters: readonly TypeParameterDeclaration[] | undefined, parameters: readonly ParameterDeclaration[], type: TypeNode | undefined, typeArguments?: readonly TypeNode[] | undefined) {
        const node = createSynthesizedNode(kind) as SignatureDeclaration;
        node.typeParameters = asNodeArray(typeParameters);
        node.parameters = asNodeArray(parameters);
        node.type = type;
        node.typeArguments = asNodeArray(typeArguments);
        return node;
    }

    function updateSignatureDeclaration<T extends SignatureDeclaration>(node: T, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined): T {
        return node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            ? updateNode(<T>createSignatureDeclaration(node.kind, typeParameters, parameters, type), node)
            : node;
    }

    // Types

    export function createKeywordTypeNode(kind: KeywordTypeNode["kind"]) {
        return <KeywordTypeNode>createSynthesizedNode(kind);
    }

    export function createTypePredicateNode(parameterName: Identifier | ThisTypeNode | string, type: TypeNode) {
        return createTypePredicateNodeWithModifier(/*assertsModifier*/ undefined, parameterName, type);
    }

    export function createTypePredicateNodeWithModifier(assertsModifier: AssertsToken | undefined, parameterName: Identifier | ThisTypeNode | string, type: TypeNode | undefined) {
        const node = createSynthesizedNode(SyntaxKind.TypePredicate) as TypePredicateNode;
        node.assertsModifier = assertsModifier;
        node.parameterName = asName(parameterName);
        node.type = type;
        return node;
    }

    export function updateTypePredicateNode(node: TypePredicateNode, parameterName: Identifier | ThisTypeNode, type: TypeNode) {
        return updateTypePredicateNodeWithModifier(node, node.assertsModifier, parameterName, type);
    }

    export function updateTypePredicateNodeWithModifier(node: TypePredicateNode, assertsModifier: AssertsToken | undefined, parameterName: Identifier | ThisTypeNode, type: TypeNode | undefined) {
        return node.assertsModifier !== assertsModifier
            || node.parameterName !== parameterName
            || node.type !== type
            ? updateNode(createTypePredicateNodeWithModifier(assertsModifier, parameterName, type), node)
            : node;
    }

    export function createTypeReferenceNode(typeName: string | EntityName, typeArguments: readonly TypeNode[] | undefined) {
        const node = createSynthesizedNode(SyntaxKind.TypeReference) as TypeReferenceNode;
        node.typeName = asName(typeName);
        node.typeArguments = typeArguments && parenthesizeTypeParameters(typeArguments);
        return node;
    }

    export function updateTypeReferenceNode(node: TypeReferenceNode, typeName: EntityName, typeArguments: NodeArray<TypeNode> | undefined) {
        return node.typeName !== typeName
            || node.typeArguments !== typeArguments
            ? updateNode(createTypeReferenceNode(typeName, typeArguments), node)
            : node;
    }

    export function createFunctionTypeNode(typeParameters: readonly TypeParameterDeclaration[] | undefined, parameters: readonly ParameterDeclaration[], type: TypeNode | undefined) {
        return createSignatureDeclaration(SyntaxKind.FunctionType, typeParameters, parameters, type) as FunctionTypeNode;
    }

    export function updateFunctionTypeNode(node: FunctionTypeNode, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined) {
        return updateSignatureDeclaration(node, typeParameters, parameters, type);
    }

    export function createConstructorTypeNode(typeParameters: readonly TypeParameterDeclaration[] | undefined, parameters: readonly ParameterDeclaration[], type: TypeNode | undefined) {
        return createSignatureDeclaration(SyntaxKind.ConstructorType, typeParameters, parameters, type) as ConstructorTypeNode;
    }

    export function updateConstructorTypeNode(node: ConstructorTypeNode, typeParameters: NodeArray<TypeParameterDeclaration> | undefined, parameters: NodeArray<ParameterDeclaration>, type: TypeNode | undefined) {
        return updateSignatureDeclaration(node, typeParameters, parameters, type);
    }

    export function createTypeQueryNode(exprName: EntityName) {
        const node = createSynthesizedNode(SyntaxKind.TypeQuery) as TypeQueryNode;
        node.exprName = exprName;
        return node;
    }

    export function updateTypeQueryNode(node: TypeQueryNode, exprName: EntityName) {
        return node.exprName !== exprName
            ? updateNode(createTypeQueryNode(exprName), node)
            : node;
    }

    export function createTypeLiteralNode(members: readonly TypeElement[] | undefined) {
        const node = createSynthesizedNode(SyntaxKind.TypeLiteral) as TypeLiteralNode;
        node.members = createNodeArray(members);
        return node;
    }

    export function updateTypeLiteralNode(node: TypeLiteralNode, members: NodeArray<TypeElement>) {
        return node.members !== members
            ? updateNode(createTypeLiteralNode(members), node)
            : node;
    }

    export function createArrayTypeNode(elementType: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.ArrayType) as ArrayTypeNode;
        node.elementType = parenthesizeArrayTypeMember(elementType);
        return node;
    }

    export function updateArrayTypeNode(node: ArrayTypeNode, elementType: TypeNode): ArrayTypeNode {
        return node.elementType !== elementType
            ? updateNode(createArrayTypeNode(elementType), node)
            : node;
    }

    export function createTupleTypeNode(elementTypes: readonly TypeNode[]) {
        const node = createSynthesizedNode(SyntaxKind.TupleType) as TupleTypeNode;
        node.elementTypes = createNodeArray(elementTypes);
        return node;
    }

    export function updateTupleTypeNode(node: TupleTypeNode, elementTypes: readonly TypeNode[]) {
        return node.elementTypes !== elementTypes
            ? updateNode(createTupleTypeNode(elementTypes), node)
            : node;
    }

    export function createOptionalTypeNode(type: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.OptionalType) as OptionalTypeNode;
        node.type = parenthesizeArrayTypeMember(type);
        return node;
    }

    export function updateOptionalTypeNode(node: OptionalTypeNode, type: TypeNode): OptionalTypeNode {
        return node.type !== type
            ? updateNode(createOptionalTypeNode(type), node)
            : node;
    }

    export function createRestTypeNode(type: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.RestType) as RestTypeNode;
        node.type = type;
        return node;
    }

    export function updateRestTypeNode(node: RestTypeNode, type: TypeNode): RestTypeNode {
        return node.type !== type
            ? updateNode(createRestTypeNode(type), node)
            : node;
    }

    export function createUnionTypeNode(types: readonly TypeNode[]): UnionTypeNode {
        return <UnionTypeNode>createUnionOrIntersectionTypeNode(SyntaxKind.UnionType, types);
    }

    export function updateUnionTypeNode(node: UnionTypeNode, types: NodeArray<TypeNode>) {
        return updateUnionOrIntersectionTypeNode(node, types);
    }

    export function createIntersectionTypeNode(types: readonly TypeNode[]): IntersectionTypeNode {
        return <IntersectionTypeNode>createUnionOrIntersectionTypeNode(SyntaxKind.IntersectionType, types);
    }

    export function updateIntersectionTypeNode(node: IntersectionTypeNode, types: NodeArray<TypeNode>) {
        return updateUnionOrIntersectionTypeNode(node, types);
    }

    export function createUnionOrIntersectionTypeNode(kind: SyntaxKind.UnionType | SyntaxKind.IntersectionType, types: readonly TypeNode[]) {
        const node = createSynthesizedNode(kind) as UnionTypeNode | IntersectionTypeNode;
        node.types = parenthesizeElementTypeMembers(types);
        return node;
    }

    function updateUnionOrIntersectionTypeNode<T extends UnionOrIntersectionTypeNode>(node: T, types: NodeArray<TypeNode>): T {
        return node.types !== types
            ? updateNode(<T>createUnionOrIntersectionTypeNode(node.kind, types), node)
            : node;
    }

    export function createConditionalTypeNode(checkType: TypeNode, extendsType: TypeNode, trueType: TypeNode, falseType: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.ConditionalType) as ConditionalTypeNode;
        node.checkType = parenthesizeConditionalTypeMember(checkType);
        node.extendsType = parenthesizeConditionalTypeMember(extendsType);
        node.trueType = trueType;
        node.falseType = falseType;
        return node;
    }

    export function updateConditionalTypeNode(node: ConditionalTypeNode, checkType: TypeNode, extendsType: TypeNode, trueType: TypeNode, falseType: TypeNode) {
        return node.checkType !== checkType
            || node.extendsType !== extendsType
            || node.trueType !== trueType
            || node.falseType !== falseType
            ? updateNode(createConditionalTypeNode(checkType, extendsType, trueType, falseType), node)
            : node;
    }

    export function createInferTypeNode(typeParameter: TypeParameterDeclaration) {
        const node = <InferTypeNode>createSynthesizedNode(SyntaxKind.InferType);
        node.typeParameter = typeParameter;
        return node;
    }

    export function updateInferTypeNode(node: InferTypeNode, typeParameter: TypeParameterDeclaration) {
        return node.typeParameter !== typeParameter
            ? updateNode(createInferTypeNode(typeParameter), node)
            : node;
    }

    export function createImportTypeNode(argument: TypeNode, qualifier?: EntityName, typeArguments?: readonly TypeNode[], isTypeOf?: boolean) {
        const node = <ImportTypeNode>createSynthesizedNode(SyntaxKind.ImportType);
        node.argument = argument;
        node.qualifier = qualifier;
        node.typeArguments = parenthesizeTypeParameters(typeArguments);
        node.isTypeOf = isTypeOf;
        return node;
    }

    export function updateImportTypeNode(node: ImportTypeNode, argument: TypeNode, qualifier?: EntityName, typeArguments?: readonly TypeNode[], isTypeOf?: boolean) {
        return node.argument !== argument
            || node.qualifier !== qualifier
            || node.typeArguments !== typeArguments
            || node.isTypeOf !== isTypeOf
            ? updateNode(createImportTypeNode(argument, qualifier, typeArguments, isTypeOf), node)
            : node;
    }

    export function createParenthesizedType(type: TypeNode) {
        const node = <ParenthesizedTypeNode>createSynthesizedNode(SyntaxKind.ParenthesizedType);
        node.type = type;
        return node;
    }

    export function updateParenthesizedType(node: ParenthesizedTypeNode, type: TypeNode) {
        return node.type !== type
            ? updateNode(createParenthesizedType(type), node)
            : node;
    }

    export function createThisTypeNode() {
        return <ThisTypeNode>createSynthesizedNode(SyntaxKind.ThisType);
    }

    export function createTypeOperatorNode(type: TypeNode): TypeOperatorNode;
    export function createTypeOperatorNode(operator: SyntaxKind.KeyOfKeyword | SyntaxKind.UniqueKeyword | SyntaxKind.ReadonlyKeyword, type: TypeNode): TypeOperatorNode;
    export function createTypeOperatorNode(operatorOrType: SyntaxKind.KeyOfKeyword | SyntaxKind.UniqueKeyword | SyntaxKind.ReadonlyKeyword | TypeNode, type?: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.TypeOperator) as TypeOperatorNode;
        node.operator = typeof operatorOrType === "number" ? operatorOrType : SyntaxKind.KeyOfKeyword;
        node.type = parenthesizeElementTypeMember(typeof operatorOrType === "number" ? type! : operatorOrType);
        return node;
    }

    export function updateTypeOperatorNode(node: TypeOperatorNode, type: TypeNode) {
        return node.type !== type ? updateNode(createTypeOperatorNode(node.operator, type), node) : node;
    }

    export function createIndexedAccessTypeNode(objectType: TypeNode, indexType: TypeNode) {
        const node = createSynthesizedNode(SyntaxKind.IndexedAccessType) as IndexedAccessTypeNode;
        node.objectType = parenthesizeElementTypeMember(objectType);
        node.indexType = indexType;
        return node;
    }

    export function updateIndexedAccessTypeNode(node: IndexedAccessTypeNode, objectType: TypeNode, indexType: TypeNode) {
        return node.objectType !== objectType
            || node.indexType !== indexType
            ? updateNode(createIndexedAccessTypeNode(objectType, indexType), node)
            : node;
    }

    export function createMappedTypeNode(readonlyToken: ReadonlyToken | PlusToken | MinusToken | undefined, typeParameter: TypeParameterDeclaration, questionToken: QuestionToken | PlusToken | MinusToken | undefined, type: TypeNode | undefined): MappedTypeNode {
        const node = createSynthesizedNode(SyntaxKind.MappedType) as MappedTypeNode;
        node.readonlyToken = readonlyToken;
        node.typeParameter = typeParameter;
        node.questionToken = questionToken;
        node.type = type;
        return node;
    }

    export function updateMappedTypeNode(node: MappedTypeNode, readonlyToken: ReadonlyToken | PlusToken | MinusToken | undefined, typeParameter: TypeParameterDeclaration, questionToken: QuestionToken | PlusToken | MinusToken | undefined, type: TypeNode | undefined): MappedTypeNode {
        return node.readonlyToken !== readonlyToken
            || node.typeParameter !== typeParameter
            || node.questionToken !== questionToken
            || node.type !== type
            ? updateNode(createMappedTypeNode(readonlyToken, typeParameter, questionToken, type), node)
            : node;
    }

    export function createLiteralTypeNode(literal: LiteralTypeNode["literal"]) {
        const node = createSynthesizedNode(SyntaxKind.LiteralType) as LiteralTypeNode;
        node.literal = literal;
        return node;
    }

    export function updateLiteralTypeNode(node: LiteralTypeNode, literal: LiteralTypeNode["literal"]) {
        return node.literal !== literal
            ? updateNode(createLiteralTypeNode(literal), node)
            : node;
    }

    // Binding Patterns

    export function createObjectBindingPattern(elements: readonly BindingElement[]) {
        const node = <ObjectBindingPattern>createSynthesizedNode(SyntaxKind.ObjectBindingPattern);
        node.elements = createNodeArray(elements);
        return node;
    }

    export function updateObjectBindingPattern(node: ObjectBindingPattern, elements: readonly BindingElement[]) {
        return node.elements !== elements
            ? updateNode(createObjectBindingPattern(elements), node)
            : node;
    }

    export function createArrayBindingPattern(elements: readonly ArrayBindingElement[]) {
        const node = <ArrayBindingPattern>createSynthesizedNode(SyntaxKind.ArrayBindingPattern);
        node.elements = createNodeArray(elements);
        return node;
    }

    export function updateArrayBindingPattern(node: ArrayBindingPattern, elements: readonly ArrayBindingElement[]) {
        return node.elements !== elements
            ? updateNode(createArrayBindingPattern(elements), node)
            : node;
    }

    export function createBindingElement(dotDotDotToken: DotDotDotToken | undefined, propertyName: string | PropertyName | undefined, name: string | BindingName, initializer?: Expression) {
        const node = <BindingElement>createSynthesizedNode(SyntaxKind.BindingElement);
        node.dotDotDotToken = dotDotDotToken;
        node.propertyName = asName(propertyName);
        node.name = asName(name);
        node.initializer = initializer;
        return node;
    }

    export function updateBindingElement(node: BindingElement, dotDotDotToken: DotDotDotToken | undefined, propertyName: PropertyName | undefined, name: BindingName, initializer: Expression | undefined) {
        return node.propertyName !== propertyName
            || node.dotDotDotToken !== dotDotDotToken
            || node.name !== name
            || node.initializer !== initializer
            ? updateNode(createBindingElement(dotDotDotToken, propertyName, name, initializer), node)
            : node;
    }

    // Expression

    export function createArrayLiteral(elements?: readonly Expression[], multiLine?: boolean) {
        const node = <ArrayLiteralExpression>createSynthesizedNode(SyntaxKind.ArrayLiteralExpression);
        node.elements = parenthesizeListElements(createNodeArray(elements));
        if (multiLine) node.multiLine = true;
        return node;
    }

    export function updateArrayLiteral(node: ArrayLiteralExpression, elements: readonly Expression[]) {
        return node.elements !== elements
            ? updateNode(createArrayLiteral(elements, node.multiLine), node)
            : node;
    }

    export function createObjectLiteral(properties?: readonly ObjectLiteralElementLike[], multiLine?: boolean) {
        const node = <ObjectLiteralExpression>createSynthesizedNode(SyntaxKind.ObjectLiteralExpression);
        node.properties = createNodeArray(properties);
        if (multiLine) node.multiLine = true;
        return node;
    }

    export function updateObjectLiteral(node: ObjectLiteralExpression, properties: readonly ObjectLiteralElementLike[]) {
        return node.properties !== properties
            ? updateNode(createObjectLiteral(properties, node.multiLine), node)
            : node;
    }

    export function createPropertyAccess(expression: Expression, name: string | Identifier | PrivateIdentifier) {
        const node = <PropertyAccessExpression>createSynthesizedNode(SyntaxKind.PropertyAccessExpression);
        node.expression = parenthesizeForAccess(expression);
        node.name = asName(name);
        setEmitFlags(node, EmitFlags.NoIndentation);
        return node;
    }

    export function updatePropertyAccess(node: PropertyAccessExpression, expression: Expression, name: Identifier | PrivateIdentifier) {
        if (isOptionalChain(node) && isIdentifier(node.name) && isIdentifier(name)) {
            // Not sure why this cast was necessary: the previous line should already establish that node.name is an identifier
            const theNode = node as (typeof node & { name: Identifier });
            return updatePropertyAccessChain(theNode, expression, node.questionDotToken, name);
        }
        // Because we are updating existed propertyAccess we want to inherit its emitFlags
        // instead of using the default from createPropertyAccess
        return node.expression !== expression
            || node.name !== name
            ? updateNode(setEmitFlags(createPropertyAccess(expression, name), getEmitFlags(node)), node)
            : node;
    }

    export function createPropertyAccessChain(expression: Expression, questionDotToken: QuestionDotToken | undefined, name: string | Identifier) {
        const node = <PropertyAccessChain>createSynthesizedNode(SyntaxKind.PropertyAccessExpression);
        node.flags |= NodeFlags.OptionalChain;
        node.expression = parenthesizeForAccess(expression);
        node.questionDotToken = questionDotToken;
        node.name = asName(name);
        setEmitFlags(node, EmitFlags.NoIndentation);
        return node;
    }

    export function updatePropertyAccessChain(node: PropertyAccessChain, expression: Expression, questionDotToken: QuestionDotToken | undefined, name: Identifier) {
        Debug.assert(!!(node.flags & NodeFlags.OptionalChain), "Cannot update a PropertyAccessExpression using updatePropertyAccessChain. Use updatePropertyAccess instead.");
        // Because we are updating an existing PropertyAccessChain we want to inherit its emitFlags
        // instead of using the default from createPropertyAccess
        return node.expression !== expression
            || node.questionDotToken !== questionDotToken
            || node.name !== name
            ? updateNode(setEmitFlags(createPropertyAccessChain(expression, questionDotToken, name), getEmitFlags(node)), node)
            : node;
    }

    export function createElementAccess(expression: Expression, index: number | Expression) {
        const node = <ElementAccessExpression>createSynthesizedNode(SyntaxKind.ElementAccessExpression);
        node.expression = parenthesizeForAccess(expression);
        node.argumentExpression = asExpression(index);
        return node;
    }

    export function updateElementAccess(node: ElementAccessExpression, expression: Expression, argumentExpression: Expression) {
        if (isOptionalChain(node)) {
            return updateElementAccessChain(node, expression, node.questionDotToken, argumentExpression);
        }
        return node.expression !== expression
            || node.argumentExpression !== argumentExpression
            ? updateNode(createElementAccess(expression, argumentExpression), node)
            : node;
    }

    export function createElementAccessChain(expression: Expression, questionDotToken: QuestionDotToken | undefined, index: number | Expression) {
        const node = <ElementAccessChain>createSynthesizedNode(SyntaxKind.ElementAccessExpression);
        node.flags |= NodeFlags.OptionalChain;
        node.expression = parenthesizeForAccess(expression);
        node.questionDotToken = questionDotToken;
        node.argumentExpression = asExpression(index);
        return node;
    }

    export function updateElementAccessChain(node: ElementAccessChain, expression: Expression, questionDotToken: QuestionDotToken | undefined, argumentExpression: Expression) {
        Debug.assert(!!(node.flags & NodeFlags.OptionalChain), "Cannot update an ElementAccessExpression using updateElementAccessChain. Use updateElementAccess instead.");
        return node.expression !== expression
            || node.questionDotToken !== questionDotToken
            || node.argumentExpression !== argumentExpression
            ? updateNode(createElementAccessChain(expression, questionDotToken, argumentExpression), node)
            : node;
    }

    export function createCall(expression: Expression, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[] | undefined) {
        const node = <CallExpression>createSynthesizedNode(SyntaxKind.CallExpression);
        node.expression = parenthesizeForAccess(expression);
        node.typeArguments = asNodeArray(typeArguments);
        node.arguments = parenthesizeListElements(createNodeArray(argumentsArray));
        return node;
    }

    export function updateCall(node: CallExpression, expression: Expression, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[]) {
        if (isOptionalChain(node)) {
            return updateCallChain(node, expression, node.questionDotToken, typeArguments, argumentsArray);
        }
        return node.expression !== expression
            || node.typeArguments !== typeArguments
            || node.arguments !== argumentsArray
            ? updateNode(createCall(expression, typeArguments, argumentsArray), node)
            : node;
    }

    export function createCallChain(expression: Expression, questionDotToken: QuestionDotToken | undefined, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[] | undefined) {
        const node = <CallChain>createSynthesizedNode(SyntaxKind.CallExpression);
        node.flags |= NodeFlags.OptionalChain;
        node.expression = parenthesizeForAccess(expression);
        node.questionDotToken = questionDotToken;
        node.typeArguments = asNodeArray(typeArguments);
        node.arguments = parenthesizeListElements(createNodeArray(argumentsArray));
        return node;
    }

    export function updateCallChain(node: CallChain, expression: Expression, questionDotToken: QuestionDotToken | undefined, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[]) {
        Debug.assert(!!(node.flags & NodeFlags.OptionalChain), "Cannot update a CallExpression using updateCallChain. Use updateCall instead.");
        return node.expression !== expression
            || node.questionDotToken !== questionDotToken
            || node.typeArguments !== typeArguments
            || node.arguments !== argumentsArray
            ? updateNode(createCallChain(expression, questionDotToken, typeArguments, argumentsArray), node)
            : node;
    }

    export function createNew(expression: Expression, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[] | undefined) {
        const node = <NewExpression>createSynthesizedNode(SyntaxKind.NewExpression);
        node.expression = parenthesizeForNew(expression);
        node.typeArguments = asNodeArray(typeArguments);
        node.arguments = argumentsArray ? parenthesizeListElements(createNodeArray(argumentsArray)) : undefined;
        return node;
    }

    export function updateNew(node: NewExpression, expression: Expression, typeArguments: readonly TypeNode[] | undefined, argumentsArray: readonly Expression[] | undefined) {
        return node.expression !== expression
            || node.typeArguments !== typeArguments
            || node.arguments !== argumentsArray
            ? updateNode(createNew(expression, typeArguments, argumentsArray), node)
            : node;
    }

    /** @deprecated */ export function createTaggedTemplate(tag: Expression, template: TemplateLiteral): TaggedTemplateExpression;
    export function createTaggedTemplate(tag: Expression, typeArguments: readonly TypeNode[] | undefined, template: TemplateLiteral): TaggedTemplateExpression;
    /** @internal */
    export function createTaggedTemplate(tag: Expression, typeArgumentsOrTemplate: readonly TypeNode[] | TemplateLiteral | undefined, template?: TemplateLiteral): TaggedTemplateExpression;
    export function createTaggedTemplate(tag: Expression, typeArgumentsOrTemplate: readonly TypeNode[] | TemplateLiteral | undefined, template?: TemplateLiteral) {
        const node = <TaggedTemplateExpression>createSynthesizedNode(SyntaxKind.TaggedTemplateExpression);
        node.tag = parenthesizeForAccess(tag);
        if (template) {
            node.typeArguments = asNodeArray(typeArgumentsOrTemplate as readonly TypeNode[]);
            node.template = template;
        }
        else {
            node.typeArguments = undefined;
            node.template = typeArgumentsOrTemplate as TemplateLiteral;
        }
        return node;
    }

    /** @deprecated */ export function updateTaggedTemplate(node: TaggedTemplateExpression, tag: Expression, template: TemplateLiteral): TaggedTemplateExpression;
    export function updateTaggedTemplate(node: TaggedTemplateExpression, tag: Expression, typeArguments: readonly TypeNode[] | undefined, template: TemplateLiteral): TaggedTemplateExpression;
    export function updateTaggedTemplate(node: TaggedTemplateExpression, tag: Expression, typeArgumentsOrTemplate: readonly TypeNode[] | TemplateLiteral | undefined, template?: TemplateLiteral) {
        return node.tag !== tag
            || (template
                ? node.typeArguments !== typeArgumentsOrTemplate || node.template !== template
                : node.typeArguments !== undefined || node.template !== typeArgumentsOrTemplate)
            ? updateNode(createTaggedTemplate(tag, typeArgumentsOrTemplate, template), node)
            : node;
    }

    export function createTypeAssertion(type: TypeNode, expression: Expression) {
        const node = <TypeAssertion>createSynthesizedNode(SyntaxKind.TypeAssertionExpression);
        node.type = type;
        node.expression = parenthesizePrefixOperand(expression);
        return node;
    }

    export function updateTypeAssertion(node: TypeAssertion, type: TypeNode, expression: Expression) {
        return node.type !== type
            || node.expression !== expression
            ? updateNode(createTypeAssertion(type, expression), node)
            : node;
    }

    export function createParen(expression: Expression) {
        const node = <ParenthesizedExpression>createSynthesizedNode(SyntaxKind.ParenthesizedExpression);
        node.expression = expression;
        return node;
    }

    export function updateParen(node: ParenthesizedExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createParen(expression), node)
            : node;
    }

    export function createFunctionExpression(
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: string | Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[] | undefined,
        type: TypeNode | undefined,
        body: Block) {
        const node = <FunctionExpression>createSynthesizedNode(SyntaxKind.FunctionExpression);
        node.modifiers = asNodeArray(modifiers);
        node.asteriskToken = asteriskToken;
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.parameters = createNodeArray(parameters);
        node.type = type;
        node.body = body;
        return node;
    }

    export function updateFunctionExpression(
        node: FunctionExpression,
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block) {
        return node.name !== name
            || node.modifiers !== modifiers
            || node.asteriskToken !== asteriskToken
            || node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            || node.body !== body
            ? updateNode(createFunctionExpression(modifiers, asteriskToken, name, typeParameters, parameters, type, body), node)
            : node;
    }

    export function createArrowFunction(
        modifiers: readonly Modifier[] | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        equalsGreaterThanToken: EqualsGreaterThanToken | undefined,
        body: ConciseBody) {
        const node = <ArrowFunction>createSynthesizedNode(SyntaxKind.ArrowFunction);
        node.modifiers = asNodeArray(modifiers);
        node.typeParameters = asNodeArray(typeParameters);
        node.parameters = createNodeArray(parameters);
        node.type = type;
        node.equalsGreaterThanToken = equalsGreaterThanToken || createToken(SyntaxKind.EqualsGreaterThanToken);
        node.body = parenthesizeConciseBody(body);
        return node;
    }
    export function updateArrowFunction(
        node: ArrowFunction,
        modifiers: readonly Modifier[] | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        equalsGreaterThanToken: Token<SyntaxKind.EqualsGreaterThanToken>,
        body: ConciseBody
    ): ArrowFunction {
        return node.modifiers !== modifiers
            || node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            || node.equalsGreaterThanToken !== equalsGreaterThanToken
            || node.body !== body
            ? updateNode(createArrowFunction(modifiers, typeParameters, parameters, type, equalsGreaterThanToken, body), node)
            : node;
    }

    export function createDelete(expression: Expression) {
        const node = <DeleteExpression>createSynthesizedNode(SyntaxKind.DeleteExpression);
        node.expression = parenthesizePrefixOperand(expression);
        return node;
    }

    export function updateDelete(node: DeleteExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createDelete(expression), node)
            : node;
    }

    export function createTypeOf(expression: Expression) {
        const node = <TypeOfExpression>createSynthesizedNode(SyntaxKind.TypeOfExpression);
        node.expression = parenthesizePrefixOperand(expression);
        return node;
    }

    export function updateTypeOf(node: TypeOfExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createTypeOf(expression), node)
            : node;
    }

    export function createVoid(expression: Expression) {
        const node = <VoidExpression>createSynthesizedNode(SyntaxKind.VoidExpression);
        node.expression = parenthesizePrefixOperand(expression);
        return node;
    }

    export function updateVoid(node: VoidExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createVoid(expression), node)
            : node;
    }

    export function createAwait(expression: Expression) {
        const node = <AwaitExpression>createSynthesizedNode(SyntaxKind.AwaitExpression);
        node.expression = parenthesizePrefixOperand(expression);
        return node;
    }

    export function updateAwait(node: AwaitExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createAwait(expression), node)
            : node;
    }

    export function createPrefix(operator: PrefixUnaryOperator, operand: Expression) {
        const node = <PrefixUnaryExpression>createSynthesizedNode(SyntaxKind.PrefixUnaryExpression);
        node.operator = operator;
        node.operand = parenthesizePrefixOperand(operand);
        return node;
    }

    export function updatePrefix(node: PrefixUnaryExpression, operand: Expression) {
        return node.operand !== operand
            ? updateNode(createPrefix(node.operator, operand), node)
            : node;
    }

    export function createPostfix(operand: Expression, operator: PostfixUnaryOperator) {
        const node = <PostfixUnaryExpression>createSynthesizedNode(SyntaxKind.PostfixUnaryExpression);
        node.operand = parenthesizePostfixOperand(operand);
        node.operator = operator;
        return node;
    }

    export function updatePostfix(node: PostfixUnaryExpression, operand: Expression) {
        return node.operand !== operand
            ? updateNode(createPostfix(operand, node.operator), node)
            : node;
    }

    export function createBinary(left: Expression, operator: BinaryOperator | BinaryOperatorToken, right: Expression) {
        const node = <BinaryExpression>createSynthesizedNode(SyntaxKind.BinaryExpression);
        const operatorToken = asToken(operator);
        const operatorKind = operatorToken.kind;
        node.left = parenthesizeBinaryOperand(operatorKind, left, /*isLeftSideOfBinary*/ true, /*leftOperand*/ undefined);
        node.operatorToken = operatorToken;
        node.right = parenthesizeBinaryOperand(operatorKind, right, /*isLeftSideOfBinary*/ false, node.left);
        return node;
    }

    export function updateBinary(node: BinaryExpression, left: Expression, right: Expression, operator?: BinaryOperator | BinaryOperatorToken) {
        return node.left !== left
            || node.right !== right
            ? updateNode(createBinary(left, operator || node.operatorToken, right), node)
            : node;
    }

    /** @deprecated */ export function createConditional(condition: Expression, whenTrue: Expression, whenFalse: Expression): ConditionalExpression;
    export function createConditional(condition: Expression, questionToken: QuestionToken, whenTrue: Expression, colonToken: ColonToken, whenFalse: Expression): ConditionalExpression;
    export function createConditional(condition: Expression, questionTokenOrWhenTrue: QuestionToken | Expression, whenTrueOrWhenFalse: Expression, colonToken?: ColonToken, whenFalse?: Expression) {
        const node = <ConditionalExpression>createSynthesizedNode(SyntaxKind.ConditionalExpression);
        node.condition = parenthesizeForConditionalHead(condition);
        node.questionToken = whenFalse ? <QuestionToken>questionTokenOrWhenTrue : createToken(SyntaxKind.QuestionToken);
        node.whenTrue = parenthesizeSubexpressionOfConditionalExpression(whenFalse ? whenTrueOrWhenFalse : <Expression>questionTokenOrWhenTrue);
        node.colonToken = whenFalse ? colonToken! : createToken(SyntaxKind.ColonToken);
        node.whenFalse = parenthesizeSubexpressionOfConditionalExpression(whenFalse ? whenFalse : whenTrueOrWhenFalse);
        return node;
    }
    export function updateConditional(
        node: ConditionalExpression,
        condition: Expression,
        questionToken: Token<SyntaxKind.QuestionToken>,
        whenTrue: Expression,
        colonToken: Token<SyntaxKind.ColonToken>,
        whenFalse: Expression
    ): ConditionalExpression {
        return node.condition !== condition
            || node.questionToken !== questionToken
            || node.whenTrue !== whenTrue
            || node.colonToken !== colonToken
            || node.whenFalse !== whenFalse
            ? updateNode(createConditional(condition, questionToken, whenTrue, colonToken, whenFalse), node)
            : node;
    }

    export function createTemplateExpression(head: TemplateHead, templateSpans: readonly TemplateSpan[]) {
        const node = <TemplateExpression>createSynthesizedNode(SyntaxKind.TemplateExpression);
        node.head = head;
        node.templateSpans = createNodeArray(templateSpans);
        return node;
    }

    export function updateTemplateExpression(node: TemplateExpression, head: TemplateHead, templateSpans: readonly TemplateSpan[]) {
        return node.head !== head
            || node.templateSpans !== templateSpans
            ? updateNode(createTemplateExpression(head, templateSpans), node)
            : node;
    }

    let rawTextScanner: Scanner | undefined;
    const invalidValueSentinel: object = {};

    function getCookedText(kind: TemplateLiteralToken["kind"], rawText: string) {
        if (!rawTextScanner) {
            rawTextScanner = createScanner(ScriptTarget.Latest, /*skipTrivia*/ false, LanguageVariant.Standard);
        }
        switch (kind) {
            case SyntaxKind.NoSubstitutionTemplateLiteral:
                rawTextScanner.setText("`" + rawText + "`");
                break;
            case SyntaxKind.TemplateHead:
                rawTextScanner.setText("`" + rawText + "${");
                break;
            case SyntaxKind.TemplateMiddle:
                rawTextScanner.setText("}" + rawText + "${");
                break;
            case SyntaxKind.TemplateTail:
                rawTextScanner.setText("}" + rawText + "`");
                break;
        }

        let token = rawTextScanner.scan();
        if (token === SyntaxKind.CloseBracketToken) {
            token = rawTextScanner.reScanTemplateToken(/* isTaggedTemplate */ false);
        }

        if (rawTextScanner.isUnterminated()) {
            rawTextScanner.setText(undefined);
            return invalidValueSentinel;
        }

        let tokenValue: string | undefined;
        switch (token) {
            case SyntaxKind.NoSubstitutionTemplateLiteral:
            case SyntaxKind.TemplateHead:
            case SyntaxKind.TemplateMiddle:
            case SyntaxKind.TemplateTail:
                tokenValue = rawTextScanner.getTokenValue();
                break;
        }

        if (rawTextScanner.scan() !== SyntaxKind.EndOfFileToken) {
            rawTextScanner.setText(undefined);
            return invalidValueSentinel;
        }

        rawTextScanner.setText(undefined);
        return tokenValue;
    }

    function createTemplateLiteralLikeNode(kind: TemplateLiteralToken["kind"], text: string, rawText: string | undefined) {
        const node = <TemplateLiteralLikeNode>createSynthesizedNode(kind);
        node.text = text;
        if (rawText === undefined || text === rawText) {
            node.rawText = rawText;
        }
        else {
            const cooked = getCookedText(kind, rawText);
            if (typeof cooked === "object") {
                return Debug.fail("Invalid raw text");
            }

            Debug.assert(text === cooked, "Expected argument 'text' to be the normalized (i.e. 'cooked') version of argument 'rawText'.");
            node.rawText = rawText;
        }
        return node;
    }

    export function createTemplateHead(text: string, rawText?: string) {
        const node = <TemplateHead>createTemplateLiteralLikeNode(SyntaxKind.TemplateHead, text, rawText);
        node.text = text;
        return node;
    }

    export function createTemplateMiddle(text: string, rawText?: string) {
        const node = <TemplateMiddle>createTemplateLiteralLikeNode(SyntaxKind.TemplateMiddle, text, rawText);
        node.text = text;
        return node;
    }

    export function createTemplateTail(text: string, rawText?: string) {
        const node = <TemplateTail>createTemplateLiteralLikeNode(SyntaxKind.TemplateTail, text, rawText);
        node.text = text;
        return node;
    }

    export function createNoSubstitutionTemplateLiteral(text: string, rawText?: string) {
        const node = <NoSubstitutionTemplateLiteral>createTemplateLiteralLikeNode(SyntaxKind.NoSubstitutionTemplateLiteral, text, rawText);
        return node;
    }

    export function createYield(expression?: Expression): YieldExpression;
    export function createYield(asteriskToken: AsteriskToken | undefined, expression: Expression): YieldExpression;
    export function createYield(asteriskTokenOrExpression?: AsteriskToken | undefined | Expression, expression?: Expression) {
        const node = <YieldExpression>createSynthesizedNode(SyntaxKind.YieldExpression);
        node.asteriskToken = asteriskTokenOrExpression && asteriskTokenOrExpression.kind === SyntaxKind.AsteriskToken ? <AsteriskToken>asteriskTokenOrExpression : undefined;
        node.expression = asteriskTokenOrExpression && asteriskTokenOrExpression.kind !== SyntaxKind.AsteriskToken ? asteriskTokenOrExpression : expression;
        return node;
    }

    export function updateYield(node: YieldExpression, asteriskToken: AsteriskToken | undefined, expression: Expression) {
        return node.expression !== expression
            || node.asteriskToken !== asteriskToken
            ? updateNode(createYield(asteriskToken, expression), node)
            : node;
    }

    export function createSpread(expression: Expression) {
        const node = <SpreadElement>createSynthesizedNode(SyntaxKind.SpreadElement);
        node.expression = parenthesizeExpressionForList(expression);
        return node;
    }

    export function updateSpread(node: SpreadElement, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createSpread(expression), node)
            : node;
    }

    export function createClassExpression(
        modifiers: readonly Modifier[] | undefined,
        name: string | Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly ClassElement[]) {
        const node = <ClassExpression>createSynthesizedNode(SyntaxKind.ClassExpression);
        node.decorators = undefined;
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.heritageClauses = asNodeArray(heritageClauses);
        node.members = createNodeArray(members);
        return node;
    }

    export function updateClassExpression(
        node: ClassExpression,
        modifiers: readonly Modifier[] | undefined,
        name: Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly ClassElement[]) {
        return node.modifiers !== modifiers
            || node.name !== name
            || node.typeParameters !== typeParameters
            || node.heritageClauses !== heritageClauses
            || node.members !== members
            ? updateNode(createClassExpression(modifiers, name, typeParameters, heritageClauses, members), node)
            : node;
    }

    export function createOmittedExpression() {
        return <OmittedExpression>createSynthesizedNode(SyntaxKind.OmittedExpression);
    }

    export function createExpressionWithTypeArguments(typeArguments: readonly TypeNode[] | undefined, expression: Expression) {
        const node = <ExpressionWithTypeArguments>createSynthesizedNode(SyntaxKind.ExpressionWithTypeArguments);
        node.expression = parenthesizeForAccess(expression);
        node.typeArguments = asNodeArray(typeArguments);
        return node;
    }

    export function updateExpressionWithTypeArguments(node: ExpressionWithTypeArguments, typeArguments: readonly TypeNode[] | undefined, expression: Expression) {
        return node.typeArguments !== typeArguments
            || node.expression !== expression
            ? updateNode(createExpressionWithTypeArguments(typeArguments, expression), node)
            : node;
    }

    export function createAsExpression(expression: Expression, type: TypeNode) {
        const node = <AsExpression>createSynthesizedNode(SyntaxKind.AsExpression);
        node.expression = expression;
        node.type = type;
        return node;
    }

    export function updateAsExpression(node: AsExpression, expression: Expression, type: TypeNode) {
        return node.expression !== expression
            || node.type !== type
            ? updateNode(createAsExpression(expression, type), node)
            : node;
    }

    export function createNonNullExpression(expression: Expression) {
        const node = <NonNullExpression>createSynthesizedNode(SyntaxKind.NonNullExpression);
        node.expression = parenthesizeForAccess(expression);
        return node;
    }

    export function updateNonNullExpression(node: NonNullExpression, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createNonNullExpression(expression), node)
            : node;
    }

    export function createMetaProperty(keywordToken: MetaProperty["keywordToken"], name: Identifier) {
        const node = <MetaProperty>createSynthesizedNode(SyntaxKind.MetaProperty);
        node.keywordToken = keywordToken;
        node.name = name;
        return node;
    }

    export function updateMetaProperty(node: MetaProperty, name: Identifier) {
        return node.name !== name
            ? updateNode(createMetaProperty(node.keywordToken, name), node)
            : node;
    }

    // Misc

    export function createTemplateSpan(expression: Expression, literal: TemplateMiddle | TemplateTail) {
        const node = <TemplateSpan>createSynthesizedNode(SyntaxKind.TemplateSpan);
        node.expression = expression;
        node.literal = literal;
        return node;
    }

    export function updateTemplateSpan(node: TemplateSpan, expression: Expression, literal: TemplateMiddle | TemplateTail) {
        return node.expression !== expression
            || node.literal !== literal
            ? updateNode(createTemplateSpan(expression, literal), node)
            : node;
    }

    export function createSemicolonClassElement() {
        return <SemicolonClassElement>createSynthesizedNode(SyntaxKind.SemicolonClassElement);
    }

    // Element

    export function createBlock(statements: readonly Statement[], multiLine?: boolean): Block {
        const block = <Block>createSynthesizedNode(SyntaxKind.Block);
        block.statements = createNodeArray(statements);
        if (multiLine) block.multiLine = multiLine;
        return block;
    }

    export function updateBlock(node: Block, statements: readonly Statement[]) {
        return node.statements !== statements
            ? updateNode(createBlock(statements, node.multiLine), node)
            : node;
    }

    export function createVariableStatement(modifiers: readonly Modifier[] | undefined, declarationList: VariableDeclarationList | readonly VariableDeclaration[]) {
        const node = <VariableStatement>createSynthesizedNode(SyntaxKind.VariableStatement);
        node.decorators = undefined;
        node.modifiers = asNodeArray(modifiers);
        node.declarationList = isArray(declarationList) ? createVariableDeclarationList(declarationList) : declarationList;
        return node;
    }

    export function updateVariableStatement(node: VariableStatement, modifiers: readonly Modifier[] | undefined, declarationList: VariableDeclarationList) {
        return node.modifiers !== modifiers
            || node.declarationList !== declarationList
            ? updateNode(createVariableStatement(modifiers, declarationList), node)
            : node;
    }

    export function createEmptyStatement() {
        return <EmptyStatement>createSynthesizedNode(SyntaxKind.EmptyStatement);
    }

    export function createExpressionStatement(expression: Expression): ExpressionStatement {
        const node = <ExpressionStatement>createSynthesizedNode(SyntaxKind.ExpressionStatement);
        node.expression = parenthesizeExpressionForExpressionStatement(expression);
        return node;
    }

    export function updateExpressionStatement(node: ExpressionStatement, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createExpressionStatement(expression), node)
            : node;
    }

    /** @deprecated Use `createExpressionStatement` instead.  */
    export const createStatement = createExpressionStatement;
    /** @deprecated Use `updateExpressionStatement` instead.  */
    export const updateStatement = updateExpressionStatement;

    export function createIf(expression: Expression, thenStatement: Statement, elseStatement?: Statement) {
        const node = <IfStatement>createSynthesizedNode(SyntaxKind.IfStatement);
        node.expression = expression;
        node.thenStatement = asEmbeddedStatement(thenStatement);
        node.elseStatement = asEmbeddedStatement(elseStatement);
        return node;
    }

    export function updateIf(node: IfStatement, expression: Expression, thenStatement: Statement, elseStatement: Statement | undefined) {
        return node.expression !== expression
            || node.thenStatement !== thenStatement
            || node.elseStatement !== elseStatement
            ? updateNode(createIf(expression, thenStatement, elseStatement), node)
            : node;
    }

    export function createDo(statement: Statement, expression: Expression) {
        const node = <DoStatement>createSynthesizedNode(SyntaxKind.DoStatement);
        node.statement = asEmbeddedStatement(statement);
        node.expression = expression;
        return node;
    }

    export function updateDo(node: DoStatement, statement: Statement, expression: Expression) {
        return node.statement !== statement
            || node.expression !== expression
            ? updateNode(createDo(statement, expression), node)
            : node;
    }

    export function createWhile(expression: Expression, statement: Statement) {
        const node = <WhileStatement>createSynthesizedNode(SyntaxKind.WhileStatement);
        node.expression = expression;
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateWhile(node: WhileStatement, expression: Expression, statement: Statement) {
        return node.expression !== expression
            || node.statement !== statement
            ? updateNode(createWhile(expression, statement), node)
            : node;
    }

    export function createFor(initializer: ForInitializer | undefined, condition: Expression | undefined, incrementor: Expression | undefined, statement: Statement) {
        const node = <ForStatement>createSynthesizedNode(SyntaxKind.ForStatement);
        node.initializer = initializer;
        node.condition = condition;
        node.incrementor = incrementor;
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateFor(node: ForStatement, initializer: ForInitializer | undefined, condition: Expression | undefined, incrementor: Expression | undefined, statement: Statement) {
        return node.initializer !== initializer
            || node.condition !== condition
            || node.incrementor !== incrementor
            || node.statement !== statement
            ? updateNode(createFor(initializer, condition, incrementor, statement), node)
            : node;
    }

    export function createForIn(initializer: ForInitializer, expression: Expression, statement: Statement) {
        const node = <ForInStatement>createSynthesizedNode(SyntaxKind.ForInStatement);
        node.initializer = initializer;
        node.expression = expression;
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateForIn(node: ForInStatement, initializer: ForInitializer, expression: Expression, statement: Statement) {
        return node.initializer !== initializer
            || node.expression !== expression
            || node.statement !== statement
            ? updateNode(createForIn(initializer, expression, statement), node)
            : node;
    }

    export function createForOf(awaitModifier: AwaitKeywordToken | undefined, initializer: ForInitializer, expression: Expression, statement: Statement) {
        const node = <ForOfStatement>createSynthesizedNode(SyntaxKind.ForOfStatement);
        node.awaitModifier = awaitModifier;
        node.initializer = initializer;
        node.expression = isCommaSequence(expression) ? createParen(expression) : expression;
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateForOf(node: ForOfStatement, awaitModifier: AwaitKeywordToken | undefined, initializer: ForInitializer, expression: Expression, statement: Statement) {
        return node.awaitModifier !== awaitModifier
            || node.initializer !== initializer
            || node.expression !== expression
            || node.statement !== statement
            ? updateNode(createForOf(awaitModifier, initializer, expression, statement), node)
            : node;
    }

    export function createContinue(label?: string | Identifier): ContinueStatement {
        const node = <ContinueStatement>createSynthesizedNode(SyntaxKind.ContinueStatement);
        node.label = asName(label);
        return node;
    }

    export function updateContinue(node: ContinueStatement, label: Identifier | undefined) {
        return node.label !== label
            ? updateNode(createContinue(label), node)
            : node;
    }

    export function createBreak(label?: string | Identifier): BreakStatement {
        const node = <BreakStatement>createSynthesizedNode(SyntaxKind.BreakStatement);
        node.label = asName(label);
        return node;
    }

    export function updateBreak(node: BreakStatement, label: Identifier | undefined) {
        return node.label !== label
            ? updateNode(createBreak(label), node)
            : node;
    }

    export function createReturn(expression?: Expression): ReturnStatement {
        const node = <ReturnStatement>createSynthesizedNode(SyntaxKind.ReturnStatement);
        node.expression = expression;
        return node;
    }

    export function updateReturn(node: ReturnStatement, expression: Expression | undefined) {
        return node.expression !== expression
            ? updateNode(createReturn(expression), node)
            : node;
    }

    export function createWith(expression: Expression, statement: Statement) {
        const node = <WithStatement>createSynthesizedNode(SyntaxKind.WithStatement);
        node.expression = expression;
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateWith(node: WithStatement, expression: Expression, statement: Statement) {
        return node.expression !== expression
            || node.statement !== statement
            ? updateNode(createWith(expression, statement), node)
            : node;
    }

    export function createSwitch(expression: Expression, caseBlock: CaseBlock): SwitchStatement {
        const node = <SwitchStatement>createSynthesizedNode(SyntaxKind.SwitchStatement);
        node.expression = parenthesizeExpressionForList(expression);
        node.caseBlock = caseBlock;
        return node;
    }

    export function updateSwitch(node: SwitchStatement, expression: Expression, caseBlock: CaseBlock) {
        return node.expression !== expression
            || node.caseBlock !== caseBlock
            ? updateNode(createSwitch(expression, caseBlock), node)
            : node;
    }

    export function createLabel(label: string | Identifier, statement: Statement) {
        const node = <LabeledStatement>createSynthesizedNode(SyntaxKind.LabeledStatement);
        node.label = asName(label);
        node.statement = asEmbeddedStatement(statement);
        return node;
    }

    export function updateLabel(node: LabeledStatement, label: Identifier, statement: Statement) {
        return node.label !== label
            || node.statement !== statement
            ? updateNode(createLabel(label, statement), node)
            : node;
    }

    export function createThrow(expression: Expression) {
        const node = <ThrowStatement>createSynthesizedNode(SyntaxKind.ThrowStatement);
        node.expression = expression;
        return node;
    }

    export function updateThrow(node: ThrowStatement, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createThrow(expression), node)
            : node;
    }

    export function createTry(tryBlock: Block, catchClause: CatchClause | undefined, finallyBlock: Block | undefined) {
        const node = <TryStatement>createSynthesizedNode(SyntaxKind.TryStatement);
        node.tryBlock = tryBlock;
        node.catchClause = catchClause;
        node.finallyBlock = finallyBlock;
        return node;
    }

    export function updateTry(node: TryStatement, tryBlock: Block, catchClause: CatchClause | undefined, finallyBlock: Block | undefined) {
        return node.tryBlock !== tryBlock
            || node.catchClause !== catchClause
            || node.finallyBlock !== finallyBlock
            ? updateNode(createTry(tryBlock, catchClause, finallyBlock), node)
            : node;
    }

    export function createDebuggerStatement() {
        return <DebuggerStatement>createSynthesizedNode(SyntaxKind.DebuggerStatement);
    }

    export function createVariableDeclaration(name: string | BindingName, type?: TypeNode, initializer?: Expression) {
        /* Internally, one should probably use createTypeScriptVariableDeclaration instead and handle definite assignment assertions */
        const node = <VariableDeclaration>createSynthesizedNode(SyntaxKind.VariableDeclaration);
        node.name = asName(name);
        node.type = type;
        node.initializer = initializer !== undefined ? parenthesizeExpressionForList(initializer) : undefined;
        return node;
    }

    export function updateVariableDeclaration(node: VariableDeclaration, name: BindingName, type: TypeNode | undefined, initializer: Expression | undefined) {
        /* Internally, one should probably use updateTypeScriptVariableDeclaration instead and handle definite assignment assertions */
        return node.name !== name
            || node.type !== type
            || node.initializer !== initializer
            ? updateNode(createVariableDeclaration(name, type, initializer), node)
            : node;
    }

    /* @internal */
    export function createTypeScriptVariableDeclaration(name: string | BindingName, exclaimationToken?: Token<SyntaxKind.ExclamationToken>, type?: TypeNode, initializer?: Expression) {
        const node = <VariableDeclaration>createSynthesizedNode(SyntaxKind.VariableDeclaration);
        node.name = asName(name);
        node.type = type;
        node.initializer = initializer !== undefined ? parenthesizeExpressionForList(initializer) : undefined;
        node.exclamationToken = exclaimationToken;
        return node;
    }

    /* @internal */
    export function updateTypeScriptVariableDeclaration(node: VariableDeclaration, name: BindingName, exclaimationToken: Token<SyntaxKind.ExclamationToken> | undefined, type: TypeNode | undefined, initializer: Expression | undefined) {
        return node.name !== name
            || node.type !== type
            || node.initializer !== initializer
            || node.exclamationToken !== exclaimationToken
            ? updateNode(createTypeScriptVariableDeclaration(name, exclaimationToken, type, initializer), node)
            : node;
    }

    export function createVariableDeclarationList(declarations: readonly VariableDeclaration[], flags = NodeFlags.None) {
        const node = <VariableDeclarationList>createSynthesizedNode(SyntaxKind.VariableDeclarationList);
        node.flags |= flags & NodeFlags.BlockScoped;
        node.declarations = createNodeArray(declarations);
        return node;
    }

    export function updateVariableDeclarationList(node: VariableDeclarationList, declarations: readonly VariableDeclaration[]) {
        return node.declarations !== declarations
            ? updateNode(createVariableDeclarationList(declarations, node.flags), node)
            : node;
    }

    export function createFunctionDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: string | Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        const node = <FunctionDeclaration>createSynthesizedNode(SyntaxKind.FunctionDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.asteriskToken = asteriskToken;
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.parameters = createNodeArray(parameters);
        node.type = type;
        node.body = body;
        return node;
    }

    export function updateFunctionDeclaration(
        node: FunctionDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        asteriskToken: AsteriskToken | undefined,
        name: Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        parameters: readonly ParameterDeclaration[],
        type: TypeNode | undefined,
        body: Block | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.asteriskToken !== asteriskToken
            || node.name !== name
            || node.typeParameters !== typeParameters
            || node.parameters !== parameters
            || node.type !== type
            || node.body !== body
            ? updateNode(createFunctionDeclaration(decorators, modifiers, asteriskToken, name, typeParameters, parameters, type, body), node)
            : node;
    }

    export function createClassDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly ClassElement[]) {
        const node = <ClassDeclaration>createSynthesizedNode(SyntaxKind.ClassDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.heritageClauses = asNodeArray(heritageClauses);
        node.members = createNodeArray(members);
        return node;
    }

    export function updateClassDeclaration(
        node: ClassDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: Identifier | undefined,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly ClassElement[]) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.typeParameters !== typeParameters
            || node.heritageClauses !== heritageClauses
            || node.members !== members
            ? updateNode(createClassDeclaration(decorators, modifiers, name, typeParameters, heritageClauses, members), node)
            : node;
    }

    export function createInterfaceDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | Identifier,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly TypeElement[]) {
        const node = <InterfaceDeclaration>createSynthesizedNode(SyntaxKind.InterfaceDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.heritageClauses = asNodeArray(heritageClauses);
        node.members = createNodeArray(members);
        return node;
    }

    export function updateInterfaceDeclaration(
        node: InterfaceDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: Identifier,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        heritageClauses: readonly HeritageClause[] | undefined,
        members: readonly TypeElement[]) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.typeParameters !== typeParameters
            || node.heritageClauses !== heritageClauses
            || node.members !== members
            ? updateNode(createInterfaceDeclaration(decorators, modifiers, name, typeParameters, heritageClauses, members), node)
            : node;
    }

    export function createTypeAliasDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | Identifier,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        type: TypeNode) {
        const node = <TypeAliasDeclaration>createSynthesizedNode(SyntaxKind.TypeAliasDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.typeParameters = asNodeArray(typeParameters);
        node.type = type;
        return node;
    }

    export function updateTypeAliasDeclaration(
        node: TypeAliasDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: Identifier,
        typeParameters: readonly TypeParameterDeclaration[] | undefined,
        type: TypeNode) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.typeParameters !== typeParameters
            || node.type !== type
            ? updateNode(createTypeAliasDeclaration(decorators, modifiers, name, typeParameters, type), node)
            : node;
    }

    export function createEnumDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: string | Identifier,
        members: readonly EnumMember[]) {
        const node = <EnumDeclaration>createSynthesizedNode(SyntaxKind.EnumDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.members = createNodeArray(members);
        return node;
    }

    export function updateEnumDeclaration(
        node: EnumDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        name: Identifier,
        members: readonly EnumMember[]) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.members !== members
            ? updateNode(createEnumDeclaration(decorators, modifiers, name, members), node)
            : node;
    }

    export function createModuleDeclaration(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, name: ModuleName, body: ModuleBody | undefined, flags = NodeFlags.None) {
        const node = <ModuleDeclaration>createSynthesizedNode(SyntaxKind.ModuleDeclaration);
        node.flags |= flags & (NodeFlags.Namespace | NodeFlags.NestedNamespace | NodeFlags.GlobalAugmentation);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = name;
        node.body = body;
        return node;
    }

    export function updateModuleDeclaration(node: ModuleDeclaration, decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, name: ModuleName, body: ModuleBody | undefined) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.body !== body
            ? updateNode(createModuleDeclaration(decorators, modifiers, name, body, node.flags), node)
            : node;
    }

    export function createModuleBlock(statements: readonly Statement[]) {
        const node = <ModuleBlock>createSynthesizedNode(SyntaxKind.ModuleBlock);
        node.statements = createNodeArray(statements);
        return node;
    }

    export function updateModuleBlock(node: ModuleBlock, statements: readonly Statement[]) {
        return node.statements !== statements
            ? updateNode(createModuleBlock(statements), node)
            : node;
    }

    export function createCaseBlock(clauses: readonly CaseOrDefaultClause[]): CaseBlock {
        const node = <CaseBlock>createSynthesizedNode(SyntaxKind.CaseBlock);
        node.clauses = createNodeArray(clauses);
        return node;
    }

    export function updateCaseBlock(node: CaseBlock, clauses: readonly CaseOrDefaultClause[]) {
        return node.clauses !== clauses
            ? updateNode(createCaseBlock(clauses), node)
            : node;
    }

    export function createNamespaceExportDeclaration(name: string | Identifier) {
        const node = <NamespaceExportDeclaration>createSynthesizedNode(SyntaxKind.NamespaceExportDeclaration);
        node.name = asName(name);
        return node;
    }

    export function updateNamespaceExportDeclaration(node: NamespaceExportDeclaration, name: Identifier) {
        return node.name !== name
            ? updateNode(createNamespaceExportDeclaration(name), node)
            : node;
    }

    export function createImportEqualsDeclaration(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, name: string | Identifier, moduleReference: ModuleReference) {
        const node = <ImportEqualsDeclaration>createSynthesizedNode(SyntaxKind.ImportEqualsDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.name = asName(name);
        node.moduleReference = moduleReference;
        return node;
    }

    export function updateImportEqualsDeclaration(node: ImportEqualsDeclaration, decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, name: Identifier, moduleReference: ModuleReference) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.name !== name
            || node.moduleReference !== moduleReference
            ? updateNode(createImportEqualsDeclaration(decorators, modifiers, name, moduleReference), node)
            : node;
    }

    export function createImportDeclaration(
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        importClause: ImportClause | undefined,
        moduleSpecifier: Expression): ImportDeclaration {
        const node = <ImportDeclaration>createSynthesizedNode(SyntaxKind.ImportDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.importClause = importClause;
        node.moduleSpecifier = moduleSpecifier;
        return node;
    }

    export function updateImportDeclaration(
        node: ImportDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        importClause: ImportClause | undefined,
        moduleSpecifier: Expression) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.importClause !== importClause
            || node.moduleSpecifier !== moduleSpecifier
            ? updateNode(createImportDeclaration(decorators, modifiers, importClause, moduleSpecifier), node)
            : node;
    }

    export function createImportClause(name: Identifier | undefined, namedBindings: NamedImportBindings | undefined, isTypeOnly = false): ImportClause {
        const node = <ImportClause>createSynthesizedNode(SyntaxKind.ImportClause);
        node.name = name;
        node.namedBindings = namedBindings;
        node.isTypeOnly = isTypeOnly;
        return node;
    }

    export function updateImportClause(node: ImportClause, name: Identifier | undefined, namedBindings: NamedImportBindings | undefined, isTypeOnly: boolean) {
        return node.name !== name
            || node.namedBindings !== namedBindings
            || node.isTypeOnly !== isTypeOnly
            ? updateNode(createImportClause(name, namedBindings, isTypeOnly), node)
            : node;
    }

    export function createNamespaceImport(name: Identifier): NamespaceImport {
        const node = <NamespaceImport>createSynthesizedNode(SyntaxKind.NamespaceImport);
        node.name = name;
        return node;
    }

    export function createNamespaceExport(name: Identifier): NamespaceExport {
        const node = <NamespaceExport>createSynthesizedNode(SyntaxKind.NamespaceExport);
        node.name = name;
        return node;
    }

    export function updateNamespaceImport(node: NamespaceImport, name: Identifier) {
        return node.name !== name
            ? updateNode(createNamespaceImport(name), node)
            : node;
    }

    export function updateNamespaceExport(node: NamespaceExport, name: Identifier) {
        return node.name !== name
            ? updateNode(createNamespaceExport(name), node)
            : node;
    }

    export function createNamedImports(elements: readonly ImportSpecifier[]): NamedImports {
        const node = <NamedImports>createSynthesizedNode(SyntaxKind.NamedImports);
        node.elements = createNodeArray(elements);
        return node;
    }

    export function updateNamedImports(node: NamedImports, elements: readonly ImportSpecifier[]) {
        return node.elements !== elements
            ? updateNode(createNamedImports(elements), node)
            : node;
    }

    export function createImportSpecifier(propertyName: Identifier | undefined, name: Identifier) {
        const node = <ImportSpecifier>createSynthesizedNode(SyntaxKind.ImportSpecifier);
        node.propertyName = propertyName;
        node.name = name;
        return node;
    }

    export function updateImportSpecifier(node: ImportSpecifier, propertyName: Identifier | undefined, name: Identifier) {
        return node.propertyName !== propertyName
            || node.name !== name
            ? updateNode(createImportSpecifier(propertyName, name), node)
            : node;
    }

    export function createExportAssignment(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, isExportEquals: boolean | undefined, expression: Expression) {
        const node = <ExportAssignment>createSynthesizedNode(SyntaxKind.ExportAssignment);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.isExportEquals = isExportEquals;
        node.expression = isExportEquals ? parenthesizeBinaryOperand(SyntaxKind.EqualsToken, expression, /*isLeftSideOfBinary*/ false, /*leftOperand*/ undefined) : parenthesizeDefaultExpression(expression);
        return node;
    }

    export function updateExportAssignment(node: ExportAssignment, decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, expression: Expression) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.expression !== expression
            ? updateNode(createExportAssignment(decorators, modifiers, node.isExportEquals, expression), node)
            : node;
    }

    export function createExportDeclaration(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, exportClause: NamedExportBindings | undefined, moduleSpecifier?: Expression, isTypeOnly = false) {
        const node = <ExportDeclaration>createSynthesizedNode(SyntaxKind.ExportDeclaration);
        node.decorators = asNodeArray(decorators);
        node.modifiers = asNodeArray(modifiers);
        node.isTypeOnly = isTypeOnly;
        node.exportClause = exportClause;
        node.moduleSpecifier = moduleSpecifier;
        return node;
    }

    export function updateExportDeclaration(
        node: ExportDeclaration,
        decorators: readonly Decorator[] | undefined,
        modifiers: readonly Modifier[] | undefined,
        exportClause: NamedExportBindings | undefined,
        moduleSpecifier: Expression | undefined,
        isTypeOnly: boolean) {
        return node.decorators !== decorators
            || node.modifiers !== modifiers
            || node.isTypeOnly !== isTypeOnly
            || node.exportClause !== exportClause
            || node.moduleSpecifier !== moduleSpecifier
            ? updateNode(createExportDeclaration(decorators, modifiers, exportClause, moduleSpecifier, isTypeOnly), node)
            : node;
    }

    /* @internal */
    export function createEmptyExports() {
        return createExportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createNamedExports([]), /*moduleSpecifier*/ undefined);
    }

    export function createNamedExports(elements: readonly ExportSpecifier[]) {
        const node = <NamedExports>createSynthesizedNode(SyntaxKind.NamedExports);
        node.elements = createNodeArray(elements);
        return node;
    }

    export function updateNamedExports(node: NamedExports, elements: readonly ExportSpecifier[]) {
        return node.elements !== elements
            ? updateNode(createNamedExports(elements), node)
            : node;
    }

    export function createExportSpecifier(propertyName: string | Identifier | undefined, name: string | Identifier) {
        const node = <ExportSpecifier>createSynthesizedNode(SyntaxKind.ExportSpecifier);
        node.propertyName = asName(propertyName);
        node.name = asName(name);
        return node;
    }

    export function updateExportSpecifier(node: ExportSpecifier, propertyName: Identifier | undefined, name: Identifier) {
        return node.propertyName !== propertyName
            || node.name !== name
            ? updateNode(createExportSpecifier(propertyName, name), node)
            : node;
    }

    // Module references

    export function createExternalModuleReference(expression: Expression) {
        const node = <ExternalModuleReference>createSynthesizedNode(SyntaxKind.ExternalModuleReference);
        node.expression = expression;
        return node;
    }

    export function updateExternalModuleReference(node: ExternalModuleReference, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createExternalModuleReference(expression), node)
            : node;
    }

    // JSDoc

    /* @internal */
    export function createJSDocTypeExpression(type: TypeNode): JSDocTypeExpression {
        const node = createSynthesizedNode(SyntaxKind.JSDocTypeExpression) as JSDocTypeExpression;
        node.type = type;
        return node;
    }

    /* @internal */
    export function createJSDocTypeTag(typeExpression: JSDocTypeExpression, comment?: string): JSDocTypeTag {
        const tag = createJSDocTag<JSDocTypeTag>(SyntaxKind.JSDocTypeTag, "type");
        tag.typeExpression = typeExpression;
        tag.comment = comment;
        return tag;
    }

    /* @internal */
    export function createJSDocReturnTag(typeExpression?: JSDocTypeExpression, comment?: string): JSDocReturnTag {
        const tag = createJSDocTag<JSDocReturnTag>(SyntaxKind.JSDocReturnTag, "returns");
        tag.typeExpression = typeExpression;
        tag.comment = comment;
        return tag;
    }

    /** @internal */
    export function createJSDocThisTag(typeExpression?: JSDocTypeExpression): JSDocThisTag {
        const tag = createJSDocTag<JSDocThisTag>(SyntaxKind.JSDocThisTag, "this");
        tag.typeExpression = typeExpression;
        return tag;
    }

    /* @internal */
    export function createJSDocParamTag(name: EntityName, isBracketed: boolean, typeExpression?: JSDocTypeExpression, comment?: string): JSDocParameterTag {
        const tag = createJSDocTag<JSDocParameterTag>(SyntaxKind.JSDocParameterTag, "param");
        tag.typeExpression = typeExpression;
        tag.name = name;
        tag.isBracketed = isBracketed;
        tag.comment = comment;
        return tag;
    }

    /* @internal */
    export function createJSDocClassTag(): JSDocClassTag {
        return createJSDocTag<JSDocClassTag>(SyntaxKind.JSDocClassTag, "class");
    }


    /* @internal */
    export function createJSDocComment(comment?: string | undefined, tags?: NodeArray<JSDocTag> | undefined) {
        const node = createSynthesizedNode(SyntaxKind.JSDocComment) as JSDoc;
        node.comment = comment;
        node.tags = tags;
        return node;
    }

    /* @internal */
    function createJSDocTag<T extends JSDocTag>(kind: T["kind"], tagName: string): T {
        const node = createSynthesizedNode(kind) as T;
        node.tagName = createIdentifier(tagName);
        return node;
    }

    // JSX

    export function createJsxElement(openingElement: JsxOpeningElement, children: readonly JsxChild[], closingElement: JsxClosingElement) {
        const node = <JsxElement>createSynthesizedNode(SyntaxKind.JsxElement);
        node.openingElement = openingElement;
        node.children = createNodeArray(children);
        node.closingElement = closingElement;
        return node;
    }

    export function updateJsxElement(node: JsxElement, openingElement: JsxOpeningElement, children: readonly JsxChild[], closingElement: JsxClosingElement) {
        return node.openingElement !== openingElement
            || node.children !== children
            || node.closingElement !== closingElement
            ? updateNode(createJsxElement(openingElement, children, closingElement), node)
            : node;
    }

    export function createJsxSelfClosingElement(tagName: JsxTagNameExpression, typeArguments: readonly TypeNode[] | undefined, attributes: JsxAttributes) {
        const node = <JsxSelfClosingElement>createSynthesizedNode(SyntaxKind.JsxSelfClosingElement);
        node.tagName = tagName;
        node.typeArguments = asNodeArray(typeArguments);
        node.attributes = attributes;
        return node;
    }

    export function updateJsxSelfClosingElement(node: JsxSelfClosingElement, tagName: JsxTagNameExpression, typeArguments: readonly TypeNode[] | undefined, attributes: JsxAttributes) {
        return node.tagName !== tagName
            || node.typeArguments !== typeArguments
            || node.attributes !== attributes
            ? updateNode(createJsxSelfClosingElement(tagName, typeArguments, attributes), node)
            : node;
    }

    export function createJsxOpeningElement(tagName: JsxTagNameExpression, typeArguments: readonly TypeNode[] | undefined, attributes: JsxAttributes) {
        const node = <JsxOpeningElement>createSynthesizedNode(SyntaxKind.JsxOpeningElement);
        node.tagName = tagName;
        node.typeArguments = asNodeArray(typeArguments);
        node.attributes = attributes;
        return node;
    }

    export function updateJsxOpeningElement(node: JsxOpeningElement, tagName: JsxTagNameExpression, typeArguments: readonly TypeNode[] | undefined, attributes: JsxAttributes) {
        return node.tagName !== tagName
            || node.typeArguments !== typeArguments
            || node.attributes !== attributes
            ? updateNode(createJsxOpeningElement(tagName, typeArguments, attributes), node)
            : node;
    }

    export function createJsxClosingElement(tagName: JsxTagNameExpression) {
        const node = <JsxClosingElement>createSynthesizedNode(SyntaxKind.JsxClosingElement);
        node.tagName = tagName;
        return node;
    }

    export function updateJsxClosingElement(node: JsxClosingElement, tagName: JsxTagNameExpression) {
        return node.tagName !== tagName
            ? updateNode(createJsxClosingElement(tagName), node)
            : node;
    }

    export function createJsxFragment(openingFragment: JsxOpeningFragment, children: readonly JsxChild[], closingFragment: JsxClosingFragment) {
        const node = <JsxFragment>createSynthesizedNode(SyntaxKind.JsxFragment);
        node.openingFragment = openingFragment;
        node.children = createNodeArray(children);
        node.closingFragment = closingFragment;
        return node;
    }

    export function createJsxText(text: string, containsOnlyTriviaWhiteSpaces?: boolean) {
        const node = <JsxText>createSynthesizedNode(SyntaxKind.JsxText);
        node.text = text;
        node.containsOnlyTriviaWhiteSpaces = !!containsOnlyTriviaWhiteSpaces;
        return node;
    }

    export function updateJsxText(node: JsxText, text: string, containsOnlyTriviaWhiteSpaces?: boolean) {
        return node.text !== text
            || node.containsOnlyTriviaWhiteSpaces !== containsOnlyTriviaWhiteSpaces
            ? updateNode(createJsxText(text, containsOnlyTriviaWhiteSpaces), node)
            : node;
    }

    export function createJsxOpeningFragment() {
        return <JsxOpeningFragment>createSynthesizedNode(SyntaxKind.JsxOpeningFragment);
    }

    export function createJsxJsxClosingFragment() {
        return <JsxClosingFragment>createSynthesizedNode(SyntaxKind.JsxClosingFragment);
    }

    export function updateJsxFragment(node: JsxFragment, openingFragment: JsxOpeningFragment, children: readonly JsxChild[], closingFragment: JsxClosingFragment) {
        return node.openingFragment !== openingFragment
            || node.children !== children
            || node.closingFragment !== closingFragment
            ? updateNode(createJsxFragment(openingFragment, children, closingFragment), node)
            : node;
    }

    export function createJsxAttribute(name: Identifier, initializer: StringLiteral | JsxExpression) {
        const node = <JsxAttribute>createSynthesizedNode(SyntaxKind.JsxAttribute);
        node.name = name;
        node.initializer = initializer;
        return node;
    }

    export function updateJsxAttribute(node: JsxAttribute, name: Identifier, initializer: StringLiteral | JsxExpression) {
        return node.name !== name
            || node.initializer !== initializer
            ? updateNode(createJsxAttribute(name, initializer), node)
            : node;
    }

    export function createJsxAttributes(properties: readonly JsxAttributeLike[]) {
        const node = <JsxAttributes>createSynthesizedNode(SyntaxKind.JsxAttributes);
        node.properties = createNodeArray(properties);
        return node;
    }

    export function updateJsxAttributes(node: JsxAttributes, properties: readonly JsxAttributeLike[]) {
        return node.properties !== properties
            ? updateNode(createJsxAttributes(properties), node)
            : node;
    }

    export function createJsxSpreadAttribute(expression: Expression) {
        const node = <JsxSpreadAttribute>createSynthesizedNode(SyntaxKind.JsxSpreadAttribute);
        node.expression = expression;
        return node;
    }

    export function updateJsxSpreadAttribute(node: JsxSpreadAttribute, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createJsxSpreadAttribute(expression), node)
            : node;
    }

    export function createJsxExpression(dotDotDotToken: DotDotDotToken | undefined, expression: Expression | undefined) {
        const node = <JsxExpression>createSynthesizedNode(SyntaxKind.JsxExpression);
        node.dotDotDotToken = dotDotDotToken;
        node.expression = expression;
        return node;
    }

    export function updateJsxExpression(node: JsxExpression, expression: Expression | undefined) {
        return node.expression !== expression
            ? updateNode(createJsxExpression(node.dotDotDotToken, expression), node)
            : node;
    }

    // Clauses

    export function createCaseClause(expression: Expression, statements: readonly Statement[]) {
        const node = <CaseClause>createSynthesizedNode(SyntaxKind.CaseClause);
        node.expression = parenthesizeExpressionForList(expression);
        node.statements = createNodeArray(statements);
        return node;
    }

    export function updateCaseClause(node: CaseClause, expression: Expression, statements: readonly Statement[]) {
        return node.expression !== expression
            || node.statements !== statements
            ? updateNode(createCaseClause(expression, statements), node)
            : node;
    }

    export function createDefaultClause(statements: readonly Statement[]) {
        const node = <DefaultClause>createSynthesizedNode(SyntaxKind.DefaultClause);
        node.statements = createNodeArray(statements);
        return node;
    }

    export function updateDefaultClause(node: DefaultClause, statements: readonly Statement[]) {
        return node.statements !== statements
            ? updateNode(createDefaultClause(statements), node)
            : node;
    }

    export function createHeritageClause(token: HeritageClause["token"], types: readonly ExpressionWithTypeArguments[]) {
        const node = <HeritageClause>createSynthesizedNode(SyntaxKind.HeritageClause);
        node.token = token;
        node.types = createNodeArray(types);
        return node;
    }

    export function updateHeritageClause(node: HeritageClause, types: readonly ExpressionWithTypeArguments[]) {
        return node.types !== types
            ? updateNode(createHeritageClause(node.token, types), node)
            : node;
    }

    export function createCatchClause(variableDeclaration: string | VariableDeclaration | undefined, block: Block) {
        const node = <CatchClause>createSynthesizedNode(SyntaxKind.CatchClause);
        node.variableDeclaration = isString(variableDeclaration) ? createVariableDeclaration(variableDeclaration) : variableDeclaration;
        node.block = block;
        return node;
    }

    export function updateCatchClause(node: CatchClause, variableDeclaration: VariableDeclaration | undefined, block: Block) {
        return node.variableDeclaration !== variableDeclaration
            || node.block !== block
            ? updateNode(createCatchClause(variableDeclaration, block), node)
            : node;
    }

    // Property assignments

    export function createPropertyAssignment(name: string | PropertyName, initializer: Expression) {
        const node = <PropertyAssignment>createSynthesizedNode(SyntaxKind.PropertyAssignment);
        node.name = asName(name);
        node.questionToken = undefined;
        node.initializer = parenthesizeExpressionForList(initializer);
        return node;
    }

    export function updatePropertyAssignment(node: PropertyAssignment, name: PropertyName, initializer: Expression) {
        return node.name !== name
            || node.initializer !== initializer
            ? updateNode(createPropertyAssignment(name, initializer), node)
            : node;
    }

    export function createShorthandPropertyAssignment(name: string | Identifier, objectAssignmentInitializer?: Expression) {
        const node = <ShorthandPropertyAssignment>createSynthesizedNode(SyntaxKind.ShorthandPropertyAssignment);
        node.name = asName(name);
        node.objectAssignmentInitializer = objectAssignmentInitializer !== undefined ? parenthesizeExpressionForList(objectAssignmentInitializer) : undefined;
        return node;
    }

    export function updateShorthandPropertyAssignment(node: ShorthandPropertyAssignment, name: Identifier, objectAssignmentInitializer: Expression | undefined) {
        return node.name !== name
            || node.objectAssignmentInitializer !== objectAssignmentInitializer
            ? updateNode(createShorthandPropertyAssignment(name, objectAssignmentInitializer), node)
            : node;
    }

    export function createSpreadAssignment(expression: Expression) {
        const node = <SpreadAssignment>createSynthesizedNode(SyntaxKind.SpreadAssignment);
        node.expression = parenthesizeExpressionForList(expression);
        return node;
    }

    export function updateSpreadAssignment(node: SpreadAssignment, expression: Expression) {
        return node.expression !== expression
            ? updateNode(createSpreadAssignment(expression), node)
            : node;
    }

    // Enum

    export function createEnumMember(name: string | PropertyName, initializer?: Expression) {
        const node = <EnumMember>createSynthesizedNode(SyntaxKind.EnumMember);
        node.name = asName(name);
        node.initializer = initializer && parenthesizeExpressionForList(initializer);
        return node;
    }

    export function updateEnumMember(node: EnumMember, name: PropertyName, initializer: Expression | undefined) {
        return node.name !== name
            || node.initializer !== initializer
            ? updateNode(createEnumMember(name, initializer), node)
            : node;
    }

    // Top-level nodes

    export function updateSourceFileNode(node: SourceFile, statements: readonly Statement[], isDeclarationFile?: boolean, referencedFiles?: SourceFile["referencedFiles"], typeReferences?: SourceFile["typeReferenceDirectives"], hasNoDefaultLib?: boolean, libReferences?: SourceFile["libReferenceDirectives"]) {
        if (
            node.statements !== statements ||
            (isDeclarationFile !== undefined && node.isDeclarationFile !== isDeclarationFile) ||
            (referencedFiles !== undefined && node.referencedFiles !== referencedFiles) ||
            (typeReferences !== undefined && node.typeReferenceDirectives !== typeReferences) ||
            (libReferences !== undefined && node.libReferenceDirectives !== libReferences) ||
            (hasNoDefaultLib !== undefined && node.hasNoDefaultLib !== hasNoDefaultLib)
        ) {
            const updated = <SourceFile>createSynthesizedNode(SyntaxKind.SourceFile);
            updated.flags |= node.flags;
            updated.statements = createNodeArray(statements);
            updated.endOfFileToken = node.endOfFileToken;
            updated.fileName = node.fileName;
            updated.path = node.path;
            updated.text = node.text;
            updated.isDeclarationFile = isDeclarationFile === undefined ? node.isDeclarationFile : isDeclarationFile;
            updated.referencedFiles = referencedFiles === undefined ? node.referencedFiles : referencedFiles;
            updated.typeReferenceDirectives = typeReferences === undefined ? node.typeReferenceDirectives : typeReferences;
            updated.hasNoDefaultLib = hasNoDefaultLib === undefined ? node.hasNoDefaultLib : hasNoDefaultLib;
            updated.libReferenceDirectives = libReferences === undefined ? node.libReferenceDirectives : libReferences;
            if (node.amdDependencies !== undefined) updated.amdDependencies = node.amdDependencies;
            if (node.moduleName !== undefined) updated.moduleName = node.moduleName;
            if (node.languageVariant !== undefined) updated.languageVariant = node.languageVariant;
            if (node.renamedDependencies !== undefined) updated.renamedDependencies = node.renamedDependencies;
            if (node.languageVersion !== undefined) updated.languageVersion = node.languageVersion;
            if (node.scriptKind !== undefined) updated.scriptKind = node.scriptKind;
            if (node.externalModuleIndicator !== undefined) updated.externalModuleIndicator = node.externalModuleIndicator;
            if (node.commonJsModuleIndicator !== undefined) updated.commonJsModuleIndicator = node.commonJsModuleIndicator;
            if (node.identifiers !== undefined) updated.identifiers = node.identifiers;
            if (node.nodeCount !== undefined) updated.nodeCount = node.nodeCount;
            if (node.identifierCount !== undefined) updated.identifierCount = node.identifierCount;
            if (node.symbolCount !== undefined) updated.symbolCount = node.symbolCount;
            if (node.parseDiagnostics !== undefined) updated.parseDiagnostics = node.parseDiagnostics;
            if (node.bindDiagnostics !== undefined) updated.bindDiagnostics = node.bindDiagnostics;
            if (node.bindSuggestionDiagnostics !== undefined) updated.bindSuggestionDiagnostics = node.bindSuggestionDiagnostics;
            if (node.lineMap !== undefined) updated.lineMap = node.lineMap;
            if (node.classifiableNames !== undefined) updated.classifiableNames = node.classifiableNames;
            if (node.resolvedModules !== undefined) updated.resolvedModules = node.resolvedModules;
            if (node.resolvedTypeReferenceDirectiveNames !== undefined) updated.resolvedTypeReferenceDirectiveNames = node.resolvedTypeReferenceDirectiveNames;
            if (node.imports !== undefined) updated.imports = node.imports;
            if (node.moduleAugmentations !== undefined) updated.moduleAugmentations = node.moduleAugmentations;
            if (node.pragmas !== undefined) updated.pragmas = node.pragmas;
            if (node.localJsxFactory !== undefined) updated.localJsxFactory = node.localJsxFactory;
            if (node.localJsxNamespace !== undefined) updated.localJsxNamespace = node.localJsxNamespace;
            return updateNode(updated, node);
        }

        return node;
    }

    /**
     * Creates a shallow, memberwise clone of a node for mutation.
     */
    export function getMutableClone<T extends Node>(node: T): T {
        const clone = getSynthesizedClone(node);
        clone.pos = node.pos;
        clone.end = node.end;
        clone.parent = node.parent;
        return clone;
    }

    // Transformation nodes

    /**
     * Creates a synthetic statement to act as a placeholder for a not-emitted statement in
     * order to preserve comments.
     *
     * @param original The original statement.
     */
    export function createNotEmittedStatement(original: Node) {
        const node = <NotEmittedStatement>createSynthesizedNode(SyntaxKind.NotEmittedStatement);
        node.original = original;
        setTextRange(node, original);
        return node;
    }

    /**
     * Creates a synthetic element to act as a placeholder for the end of an emitted declaration in
     * order to properly emit exports.
     */
    /* @internal */
    export function createEndOfDeclarationMarker(original: Node) {
        const node = <EndOfDeclarationMarker>createSynthesizedNode(SyntaxKind.EndOfDeclarationMarker);
        node.emitNode = {} as EmitNode;
        node.original = original;
        return node;
    }

    /**
     * Creates a synthetic element to act as a placeholder for the beginning of a merged declaration in
     * order to properly emit exports.
     */
    /* @internal */
    export function createMergeDeclarationMarker(original: Node) {
        const node = <MergeDeclarationMarker>createSynthesizedNode(SyntaxKind.MergeDeclarationMarker);
        node.emitNode = {} as EmitNode;
        node.original = original;
        return node;
    }

    /**
     * Creates a synthetic expression to act as a placeholder for a not-emitted expression in
     * order to preserve comments or sourcemap positions.
     *
     * @param expression The inner expression to emit.
     * @param original The original outer expression.
     * @param location The location for the expression. Defaults to the positions from "original" if provided.
     */
    export function createPartiallyEmittedExpression(expression: Expression, original?: Node) {
        const node = <PartiallyEmittedExpression>createSynthesizedNode(SyntaxKind.PartiallyEmittedExpression);
        node.expression = expression;
        node.original = original;
        setTextRange(node, original);
        return node;
    }

    export function updatePartiallyEmittedExpression(node: PartiallyEmittedExpression, expression: Expression) {
        if (node.expression !== expression) {
            return updateNode(createPartiallyEmittedExpression(expression, node.original), node);
        }
        return node;
    }

    function flattenCommaElements(node: Expression): Expression | readonly Expression[] {
        if (nodeIsSynthesized(node) && !isParseTreeNode(node) && !node.original && !node.emitNode && !node.id) {
            if (node.kind === SyntaxKind.CommaListExpression) {
                return (<CommaListExpression>node).elements;
            }
            if (isBinaryExpression(node) && node.operatorToken.kind === SyntaxKind.CommaToken) {
                return [node.left, node.right];
            }
        }
        return node;
    }

    export function createCommaList(elements: readonly Expression[]) {
        const node = <CommaListExpression>createSynthesizedNode(SyntaxKind.CommaListExpression);
        node.elements = createNodeArray(sameFlatMap(elements, flattenCommaElements));
        return node;
    }

    export function updateCommaList(node: CommaListExpression, elements: readonly Expression[]) {
        return node.elements !== elements
            ? updateNode(createCommaList(elements), node)
            : node;
    }

    /* @internal */
    export function createSyntheticReferenceExpression(expression: Expression, thisArg: Expression) {
        const node = <SyntheticReferenceExpression>createSynthesizedNode(SyntaxKind.SyntheticReferenceExpression);
        node.expression = expression;
        node.thisArg = thisArg;
        return node;
    }

    /* @internal */
    export function updateSyntheticReferenceExpression(node: SyntheticReferenceExpression, expression: Expression, thisArg: Expression) {
        return node.expression !== expression
            || node.thisArg !== thisArg
            ? updateNode(createSyntheticReferenceExpression(expression, thisArg), node)
            : node;
    }

    export function createBundle(sourceFiles: readonly SourceFile[], prepends: readonly (UnparsedSource | InputFiles)[] = emptyArray) {
        const node = <Bundle>createNode(SyntaxKind.Bundle);
        node.prepends = prepends;
        node.sourceFiles = sourceFiles;
        return node;
    }

    let allUnscopedEmitHelpers: ReadonlyMap<UnscopedEmitHelper> | undefined;
    function getAllUnscopedEmitHelpers() {
        return allUnscopedEmitHelpers || (allUnscopedEmitHelpers = arrayToMap([
            valuesHelper,
            readHelper,
            spreadHelper,
            spreadArraysHelper,
            restHelper,
            decorateHelper,
            metadataHelper,
            paramHelper,
            awaiterHelper,
            assignHelper,
            awaitHelper,
            asyncGeneratorHelper,
            asyncDelegator,
            asyncValues,
            extendsHelper,
            templateObjectHelper,
            generatorHelper,
            importStarHelper,
            importDefaultHelper,
            classPrivateFieldGetHelper,
            classPrivateFieldSetHelper,
            createBindingHelper,
            setModuleDefaultHelper
        ], helper => helper.name));
    }

    function createUnparsedSource() {
        const node = <UnparsedSource>createNode(SyntaxKind.UnparsedSource);
        node.prologues = emptyArray;
        node.referencedFiles = emptyArray;
        node.libReferenceDirectives = emptyArray;
        node.getLineAndCharacterOfPosition = pos => getLineAndCharacterOfPosition(node, pos);
        return node;
    }

    export function createUnparsedSourceFile(text: string): UnparsedSource;
    export function createUnparsedSourceFile(inputFile: InputFiles, type: "js" | "dts", stripInternal?: boolean): UnparsedSource;
    export function createUnparsedSourceFile(text: string, mapPath: string | undefined, map: string | undefined): UnparsedSource;
    export function createUnparsedSourceFile(textOrInputFiles: string | InputFiles, mapPathOrType?: string, mapTextOrStripInternal?: string | boolean): UnparsedSource {
        const node = createUnparsedSource();
        let stripInternal: boolean | undefined;
        let bundleFileInfo: BundleFileInfo | undefined;
        if (!isString(textOrInputFiles)) {
            Debug.assert(mapPathOrType === "js" || mapPathOrType === "dts");
            node.fileName = (mapPathOrType === "js" ? textOrInputFiles.javascriptPath : textOrInputFiles.declarationPath) || "";
            node.sourceMapPath = mapPathOrType === "js" ? textOrInputFiles.javascriptMapPath : textOrInputFiles.declarationMapPath;
            Object.defineProperties(node, {
                text: { get() { return mapPathOrType === "js" ? textOrInputFiles.javascriptText : textOrInputFiles.declarationText; } },
                sourceMapText: { get() { return mapPathOrType === "js" ? textOrInputFiles.javascriptMapText : textOrInputFiles.declarationMapText; } },
            });


            if (textOrInputFiles.buildInfo && textOrInputFiles.buildInfo.bundle) {
                node.oldFileOfCurrentEmit = textOrInputFiles.oldFileOfCurrentEmit;
                Debug.assert(mapTextOrStripInternal === undefined || typeof mapTextOrStripInternal === "boolean");
                stripInternal = mapTextOrStripInternal;
                bundleFileInfo = mapPathOrType === "js" ? textOrInputFiles.buildInfo.bundle.js : textOrInputFiles.buildInfo.bundle.dts;
                if (node.oldFileOfCurrentEmit) {
                    parseOldFileOfCurrentEmit(node, Debug.checkDefined(bundleFileInfo));
                    return node;
                }
            }
        }
        else {
            node.fileName = "";
            node.text = textOrInputFiles;
            node.sourceMapPath = mapPathOrType;
            node.sourceMapText = mapTextOrStripInternal as string;
        }
        Debug.assert(!node.oldFileOfCurrentEmit);
        parseUnparsedSourceFile(node, bundleFileInfo, stripInternal);
        return node;
    }

    function parseUnparsedSourceFile(node: UnparsedSource, bundleFileInfo: BundleFileInfo | undefined, stripInternal: boolean | undefined) {
        let prologues: UnparsedPrologue[] | undefined;
        let helpers: UnscopedEmitHelper[] | undefined;
        let referencedFiles: FileReference[] | undefined;
        let typeReferenceDirectives: string[] | undefined;
        let libReferenceDirectives: FileReference[] | undefined;
        let texts: UnparsedSourceText[] | undefined;

        for (const section of bundleFileInfo ? bundleFileInfo.sections : emptyArray) {
            switch (section.kind) {
                case BundleFileSectionKind.Prologue:
                    (prologues || (prologues = [])).push(createUnparsedNode(section, node) as UnparsedPrologue);
                    break;
                case BundleFileSectionKind.EmitHelpers:
                    (helpers || (helpers = [])).push(getAllUnscopedEmitHelpers().get(section.data)!);
                    break;
                case BundleFileSectionKind.NoDefaultLib:
                    node.hasNoDefaultLib = true;
                    break;
                case BundleFileSectionKind.Reference:
                    (referencedFiles || (referencedFiles = [])).push({ pos: -1, end: -1, fileName: section.data });
                    break;
                case BundleFileSectionKind.Type:
                    (typeReferenceDirectives || (typeReferenceDirectives = [])).push(section.data);
                    break;
                case BundleFileSectionKind.Lib:
                    (libReferenceDirectives || (libReferenceDirectives = [])).push({ pos: -1, end: -1, fileName: section.data });
                    break;
                case BundleFileSectionKind.Prepend:
                    const prependNode = createUnparsedNode(section, node) as UnparsedPrepend;
                    let prependTexts: UnparsedTextLike[] | undefined;
                    for (const text of section.texts) {
                        if (!stripInternal || text.kind !== BundleFileSectionKind.Internal) {
                            (prependTexts || (prependTexts = [])).push(createUnparsedNode(text, node) as UnparsedTextLike);
                        }
                    }
                    prependNode.texts = prependTexts || emptyArray;
                    (texts || (texts = [])).push(prependNode);
                    break;
                case BundleFileSectionKind.Internal:
                    if (stripInternal) {
                        if (!texts) texts = [];
                        break;
                    }
                    // falls through

                case BundleFileSectionKind.Text:
                    (texts || (texts = [])).push(createUnparsedNode(section, node) as UnparsedTextLike);
                    break;
                default:
                    Debug.assertNever(section);
            }
        }

        node.prologues = prologues || emptyArray;
        node.helpers = helpers;
        node.referencedFiles = referencedFiles || emptyArray;
        node.typeReferenceDirectives = typeReferenceDirectives;
        node.libReferenceDirectives = libReferenceDirectives || emptyArray;
        node.texts = texts || [<UnparsedTextLike>createUnparsedNode({ kind: BundleFileSectionKind.Text, pos: 0, end: node.text.length }, node)];
    }

    function parseOldFileOfCurrentEmit(node: UnparsedSource, bundleFileInfo: BundleFileInfo) {
        Debug.assert(!!node.oldFileOfCurrentEmit);
        let texts: UnparsedTextLike[] | undefined;
        let syntheticReferences: UnparsedSyntheticReference[] | undefined;
        for (const section of bundleFileInfo.sections) {
            switch (section.kind) {
                case BundleFileSectionKind.Internal:
                case BundleFileSectionKind.Text:
                    (texts || (texts = [])).push(createUnparsedNode(section, node) as UnparsedTextLike);
                    break;

                case BundleFileSectionKind.NoDefaultLib:
                case BundleFileSectionKind.Reference:
                case BundleFileSectionKind.Type:
                case BundleFileSectionKind.Lib:
                    (syntheticReferences || (syntheticReferences = [])).push(createUnparsedSyntheticReference(section, node));
                    break;

                // Ignore
                case BundleFileSectionKind.Prologue:
                case BundleFileSectionKind.EmitHelpers:
                case BundleFileSectionKind.Prepend:
                    break;

                default:
                    Debug.assertNever(section);
            }
        }
        node.texts = texts || emptyArray;
        node.helpers = map(bundleFileInfo.sources && bundleFileInfo.sources.helpers, name => getAllUnscopedEmitHelpers().get(name)!);
        node.syntheticReferences = syntheticReferences;
        return node;
    }

    function mapBundleFileSectionKindToSyntaxKind(kind: BundleFileSectionKind): SyntaxKind {
        switch (kind) {
            case BundleFileSectionKind.Prologue: return SyntaxKind.UnparsedPrologue;
            case BundleFileSectionKind.Prepend: return SyntaxKind.UnparsedPrepend;
            case BundleFileSectionKind.Internal: return SyntaxKind.UnparsedInternalText;
            case BundleFileSectionKind.Text: return SyntaxKind.UnparsedText;

            case BundleFileSectionKind.EmitHelpers:
            case BundleFileSectionKind.NoDefaultLib:
            case BundleFileSectionKind.Reference:
            case BundleFileSectionKind.Type:
            case BundleFileSectionKind.Lib:
                return Debug.fail(`BundleFileSectionKind: ${kind} not yet mapped to SyntaxKind`);

            default:
                return Debug.assertNever(kind);
        }
    }

    function createUnparsedNode(section: BundleFileSection, parent: UnparsedSource): UnparsedNode {
        const node = createNode(mapBundleFileSectionKindToSyntaxKind(section.kind), section.pos, section.end) as UnparsedNode;
        node.parent = parent;
        node.data = section.data;
        return node;
    }

    function createUnparsedSyntheticReference(section: BundleFileHasNoDefaultLib | BundleFileReference, parent: UnparsedSource) {
        const node = createNode(SyntaxKind.UnparsedSyntheticReference, section.pos, section.end) as UnparsedSyntheticReference;
        node.parent = parent;
        node.data = section.data;
        node.section = section;
        return node;
    }

    export function createInputFiles(
        javascriptText: string,
        declarationText: string
    ): InputFiles;
    export function createInputFiles(
        readFileText: (path: string) => string | undefined,
        javascriptPath: string,
        javascriptMapPath: string | undefined,
        declarationPath: string,
        declarationMapPath: string | undefined,
        buildInfoPath: string | undefined
    ): InputFiles;
    export function createInputFiles(
        javascriptText: string,
        declarationText: string,
        javascriptMapPath: string | undefined,
        javascriptMapText: string | undefined,
        declarationMapPath: string | undefined,
        declarationMapText: string | undefined
    ): InputFiles;
    /*@internal*/
    export function createInputFiles(
        javascriptText: string,
        declarationText: string,
        javascriptMapPath: string | undefined,
        javascriptMapText: string | undefined,
        declarationMapPath: string | undefined,
        declarationMapText: string | undefined,
        javascriptPath: string | undefined,
        declarationPath: string | undefined,
        buildInfoPath?: string | undefined,
        buildInfo?: BuildInfo,
        oldFileOfCurrentEmit?: boolean
    ): InputFiles;
    export function createInputFiles(
        javascriptTextOrReadFileText: string | ((path: string) => string | undefined),
        declarationTextOrJavascriptPath: string,
        javascriptMapPath?: string,
        javascriptMapTextOrDeclarationPath?: string,
        declarationMapPath?: string,
        declarationMapTextOrBuildInfoPath?: string,
        javascriptPath?: string | undefined,
        declarationPath?: string | undefined,
        buildInfoPath?: string | undefined,
        buildInfo?: BuildInfo,
        oldFileOfCurrentEmit?: boolean
    ): InputFiles {
        const node = <InputFiles>createNode(SyntaxKind.InputFiles);
        if (!isString(javascriptTextOrReadFileText)) {
            const cache = createMap<string | false>();
            const textGetter = (path: string | undefined) => {
                if (path === undefined) return undefined;
                let value = cache.get(path);
                if (value === undefined) {
                    value = javascriptTextOrReadFileText(path);
                    cache.set(path, value !== undefined ? value : false);
                }
                return value !== false ? value as string : undefined;
            };
            const definedTextGetter = (path: string) => {
                const result = textGetter(path);
                return result !== undefined ? result : `/* Input file ${path} was missing */\r\n`;
            };
            let buildInfo: BuildInfo | false;
            const getAndCacheBuildInfo = (getText: () => string | undefined) => {
                if (buildInfo === undefined) {
                    const result = getText();
                    buildInfo = result !== undefined ? getBuildInfo(result) : false;
                }
                return buildInfo || undefined;
            };
            node.javascriptPath = declarationTextOrJavascriptPath;
            node.javascriptMapPath = javascriptMapPath;
            node.declarationPath = Debug.checkDefined(javascriptMapTextOrDeclarationPath);
            node.declarationMapPath = declarationMapPath;
            node.buildInfoPath = declarationMapTextOrBuildInfoPath;
            Object.defineProperties(node, {
                javascriptText: { get() { return definedTextGetter(declarationTextOrJavascriptPath); } },
                javascriptMapText: { get() { return textGetter(javascriptMapPath); } }, // TODO:: if there is inline sourceMap in jsFile, use that
                declarationText: { get() { return definedTextGetter(Debug.checkDefined(javascriptMapTextOrDeclarationPath)); } },
                declarationMapText: { get() { return textGetter(declarationMapPath); } }, // TODO:: if there is inline sourceMap in dtsFile, use that
                buildInfo: { get() { return getAndCacheBuildInfo(() => textGetter(declarationMapTextOrBuildInfoPath)); } }
            });
        }
        else {
            node.javascriptText = javascriptTextOrReadFileText;
            node.javascriptMapPath = javascriptMapPath;
            node.javascriptMapText = javascriptMapTextOrDeclarationPath;
            node.declarationText = declarationTextOrJavascriptPath;
            node.declarationMapPath = declarationMapPath;
            node.declarationMapText = declarationMapTextOrBuildInfoPath;
            node.javascriptPath = javascriptPath;
            node.declarationPath = declarationPath;
            node.buildInfoPath = buildInfoPath;
            node.buildInfo = buildInfo;
            node.oldFileOfCurrentEmit = oldFileOfCurrentEmit;
        }
        return node;
    }

    export function updateBundle(node: Bundle, sourceFiles: readonly SourceFile[], prepends: readonly (UnparsedSource | InputFiles)[] = emptyArray) {
        if (node.sourceFiles !== sourceFiles || node.prepends !== prepends) {
            return createBundle(sourceFiles, prepends);
        }
        return node;
    }

    // Compound nodes

    export function createImmediatelyInvokedFunctionExpression(statements: readonly Statement[]): CallExpression;
    export function createImmediatelyInvokedFunctionExpression(statements: readonly Statement[], param: ParameterDeclaration, paramValue: Expression): CallExpression;
    export function createImmediatelyInvokedFunctionExpression(statements: readonly Statement[], param?: ParameterDeclaration, paramValue?: Expression) {
        return createCall(
            createFunctionExpression(
                /*modifiers*/ undefined,
                /*asteriskToken*/ undefined,
                /*name*/ undefined,
                /*typeParameters*/ undefined,
                /*parameters*/ param ? [param] : [],
                /*type*/ undefined,
                createBlock(statements, /*multiLine*/ true)
            ),
            /*typeArguments*/ undefined,
            /*argumentsArray*/ paramValue ? [paramValue] : []
        );
    }

    export function createImmediatelyInvokedArrowFunction(statements: readonly Statement[]): CallExpression;
    export function createImmediatelyInvokedArrowFunction(statements: readonly Statement[], param: ParameterDeclaration, paramValue: Expression): CallExpression;
    export function createImmediatelyInvokedArrowFunction(statements: readonly Statement[], param?: ParameterDeclaration, paramValue?: Expression) {
        return createCall(
            createArrowFunction(
                /*modifiers*/ undefined,
                /*typeParameters*/ undefined,
                /*parameters*/ param ? [param] : [],
                /*type*/ undefined,
                /*equalsGreaterThanToken*/ undefined,
                createBlock(statements, /*multiLine*/ true)
            ),
            /*typeArguments*/ undefined,
            /*argumentsArray*/ paramValue ? [paramValue] : []
        );
    }


    export function createComma(left: Expression, right: Expression) {
        return <Expression>createBinary(left, SyntaxKind.CommaToken, right);
    }

    export function createLessThan(left: Expression, right: Expression) {
        return <Expression>createBinary(left, SyntaxKind.LessThanToken, right);
    }

    export function createAssignment(left: ObjectLiteralExpression | ArrayLiteralExpression, right: Expression): DestructuringAssignment;
    export function createAssignment(left: Expression, right: Expression): BinaryExpression;
    export function createAssignment(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.EqualsToken, right);
    }

    export function createStrictEquality(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.EqualsEqualsEqualsToken, right);
    }

    export function createStrictInequality(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.ExclamationEqualsEqualsToken, right);
    }

    export function createAdd(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.PlusToken, right);
    }

    export function createSubtract(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.MinusToken, right);
    }

    export function createPostfixIncrement(operand: Expression) {
        return createPostfix(operand, SyntaxKind.PlusPlusToken);
    }

    export function createLogicalAnd(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.AmpersandAmpersandToken, right);
    }

    export function createLogicalOr(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.BarBarToken, right);
    }

    export function createNullishCoalesce(left: Expression, right: Expression) {
        return createBinary(left, SyntaxKind.QuestionQuestionToken, right);
    }

    export function createLogicalNot(operand: Expression) {
        return createPrefix(SyntaxKind.ExclamationToken, operand);
    }

    export function createVoidZero() {
        return createVoid(createLiteral(0));
    }

    export function createExportDefault(expression: Expression) {
        return createExportAssignment(/*decorators*/ undefined, /*modifiers*/ undefined, /*isExportEquals*/ false, expression);
    }

    export function createExternalModuleExport(exportName: Identifier) {
        return createExportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined, createNamedExports([createExportSpecifier(/*propertyName*/ undefined, exportName)]));
    }

    // Utilities

    function asName<T extends Identifier | BindingName | PropertyName | EntityName | ThisTypeNode | undefined>(name: string | T): T | Identifier {
        return isString(name) ? createIdentifier(name) : name;
    }

    function asExpression<T extends Expression | undefined>(value: string | number | boolean | T): T | StringLiteral | NumericLiteral | BooleanLiteral {
        return typeof value === "string" ? createStringLiteral(value) :
            typeof value === "number" ? createNumericLiteral(""+value) :
            typeof value === "boolean" ? value ? createTrue() : createFalse() :
        value;
    }

    function asNodeArray<T extends Node>(array: readonly T[]): NodeArray<T>;
    function asNodeArray<T extends Node>(array: readonly T[] | undefined): NodeArray<T> | undefined;
    function asNodeArray<T extends Node>(array: readonly T[] | undefined): NodeArray<T> | undefined {
        return array ? createNodeArray(array) : undefined;
    }

    function asToken<TKind extends SyntaxKind>(value: TKind | Token<TKind>): Token<TKind> {
        return typeof value === "number" ? createToken(value) : value;
    }

    function asEmbeddedStatement<T extends Node>(statement: T): T | EmptyStatement;
    function asEmbeddedStatement<T extends Node>(statement: T | undefined): T | EmptyStatement | undefined;
    function asEmbeddedStatement<T extends Node>(statement: T | undefined): T | EmptyStatement | undefined {
        return statement && isNotEmittedStatement(statement) ? setTextRange(setOriginalNode(createEmptyStatement(), statement), statement) : statement;
    }

    /**
     * Clears any EmitNode entries from parse-tree nodes.
     * @param sourceFile A source file.
     */
    export function disposeEmitNodes(sourceFile: SourceFile) {
        // During transformation we may need to annotate a parse tree node with transient
        // transformation properties. As parse tree nodes live longer than transformation
        // nodes, we need to make sure we reclaim any memory allocated for custom ranges
        // from these nodes to ensure we do not hold onto entire subtrees just for position
        // information. We also need to reset these nodes to a pre-transformation state
        // for incremental parsing scenarios so that we do not impact later emit.
        sourceFile = getSourceFileOfNode(getParseTreeNode(sourceFile));
        const emitNode = sourceFile && sourceFile.emitNode;
        const annotatedNodes = emitNode && emitNode.annotatedNodes;
        if (annotatedNodes) {
            for (const node of annotatedNodes) {
                node.emitNode = undefined;
            }
        }
    }

    /**
     * Associates a node with the current transformation, initializing
     * various transient transformation properties.
     */
    /* @internal */
    export function getOrCreateEmitNode(node: Node): EmitNode {
        if (!node.emitNode) {
            if (isParseTreeNode(node)) {
                // To avoid holding onto transformation artifacts, we keep track of any
                // parse tree node we are annotating. This allows us to clean them up after
                // all transformations have completed.
                if (node.kind === SyntaxKind.SourceFile) {
                    return node.emitNode = { annotatedNodes: [node] } as EmitNode;
                }

                const sourceFile = getSourceFileOfNode(getParseTreeNode(getSourceFileOfNode(node)));
                getOrCreateEmitNode(sourceFile).annotatedNodes!.push(node);
            }

            node.emitNode = {} as EmitNode;
        }

        return node.emitNode;
    }

    /**
     * Sets `EmitFlags.NoComments` on a node and removes any leading and trailing synthetic comments.
     * @internal
     */
    export function removeAllComments<T extends Node>(node: T): T {
        const emitNode = getOrCreateEmitNode(node);
        emitNode.flags |= EmitFlags.NoComments;
        emitNode.leadingComments = undefined;
        emitNode.trailingComments = undefined;
        return node;
    }

    export function setTextRange<T extends TextRange>(range: T, location: TextRange | undefined): T {
        if (location) {
            range.pos = location.pos;
            range.end = location.end;
        }
        return range;
    }

    /**
     * Sets flags that control emit behavior of a node.
     */
    export function setEmitFlags<T extends Node>(node: T, emitFlags: EmitFlags) {
        getOrCreateEmitNode(node).flags = emitFlags;
        return node;
    }

    /**
     * Sets flags that control emit behavior of a node.
     */
    /* @internal */
    export function addEmitFlags<T extends Node>(node: T, emitFlags: EmitFlags) {
        const emitNode = getOrCreateEmitNode(node);
        emitNode.flags = emitNode.flags | emitFlags;
        return node;
    }

    /**
     * Gets a custom text range to use when emitting source maps.
     */
    export function getSourceMapRange(node: Node): SourceMapRange {
        const emitNode = node.emitNode;
        return (emitNode && emitNode.sourceMapRange) || node;
    }

    /**
     * Sets a custom text range to use when emitting source maps.
     */
    export function setSourceMapRange<T extends Node>(node: T, range: SourceMapRange | undefined) {
        getOrCreateEmitNode(node).sourceMapRange = range;
        return node;
    }

    let SourceMapSource: new (fileName: string, text: string, skipTrivia?: (pos: number) => number) => SourceMapSource;

    /**
     * Create an external source map source file reference
     */
    export function createSourceMapSource(fileName: string, text: string, skipTrivia?: (pos: number) => number): SourceMapSource {
        return new (SourceMapSource || (SourceMapSource = objectAllocator.getSourceMapSourceConstructor()))(fileName, text, skipTrivia);
    }

    /**
     * Gets the TextRange to use for source maps for a token of a node.
     */
    export function getTokenSourceMapRange(node: Node, token: SyntaxKind): SourceMapRange | undefined {
        const emitNode = node.emitNode;
        const tokenSourceMapRanges = emitNode && emitNode.tokenSourceMapRanges;
        return tokenSourceMapRanges && tokenSourceMapRanges[token];
    }

    /**
     * Sets the TextRange to use for source maps for a token of a node.
     */
    export function setTokenSourceMapRange<T extends Node>(node: T, token: SyntaxKind, range: SourceMapRange | undefined) {
        const emitNode = getOrCreateEmitNode(node);
        const tokenSourceMapRanges = emitNode.tokenSourceMapRanges || (emitNode.tokenSourceMapRanges = []);
        tokenSourceMapRanges[token] = range;
        return node;
    }

    /**
     * Gets a custom text range to use when emitting comments.
     */
    /*@internal*/
    export function getStartsOnNewLine(node: Node) {
        const emitNode = node.emitNode;
        return emitNode && emitNode.startsOnNewLine;
    }

    /**
     * Sets a custom text range to use when emitting comments.
     */
    /*@internal*/
    export function setStartsOnNewLine<T extends Node>(node: T, newLine: boolean) {
        getOrCreateEmitNode(node).startsOnNewLine = newLine;
        return node;
    }

    /**
     * Gets a custom text range to use when emitting comments.
     */
    export function getCommentRange(node: Node) {
        const emitNode = node.emitNode;
        return (emitNode && emitNode.commentRange) || node;
    }

    /**
     * Sets a custom text range to use when emitting comments.
     */
    export function setCommentRange<T extends Node>(node: T, range: TextRange) {
        getOrCreateEmitNode(node).commentRange = range;
        return node;
    }

    export function getSyntheticLeadingComments(node: Node): SynthesizedComment[] | undefined {
        const emitNode = node.emitNode;
        return emitNode && emitNode.leadingComments;
    }

    export function setSyntheticLeadingComments<T extends Node>(node: T, comments: SynthesizedComment[] | undefined) {
        getOrCreateEmitNode(node).leadingComments = comments;
        return node;
    }

    export function addSyntheticLeadingComment<T extends Node>(node: T, kind: SyntaxKind.SingleLineCommentTrivia | SyntaxKind.MultiLineCommentTrivia, text: string, hasTrailingNewLine?: boolean) {
        return setSyntheticLeadingComments(node, append<SynthesizedComment>(getSyntheticLeadingComments(node), { kind, pos: -1, end: -1, hasTrailingNewLine, text }));
    }

    export function getSyntheticTrailingComments(node: Node): SynthesizedComment[] | undefined {
        const emitNode = node.emitNode;
        return emitNode && emitNode.trailingComments;
    }

    export function setSyntheticTrailingComments<T extends Node>(node: T, comments: SynthesizedComment[] | undefined) {
        getOrCreateEmitNode(node).trailingComments = comments;
        return node;
    }

    export function addSyntheticTrailingComment<T extends Node>(node: T, kind: SyntaxKind.SingleLineCommentTrivia | SyntaxKind.MultiLineCommentTrivia, text: string, hasTrailingNewLine?: boolean) {
        return setSyntheticTrailingComments(node, append<SynthesizedComment>(getSyntheticTrailingComments(node), { kind, pos: -1, end: -1, hasTrailingNewLine, text }));
    }

    export function moveSyntheticComments<T extends Node>(node: T, original: Node): T {
        setSyntheticLeadingComments(node, getSyntheticLeadingComments(original));
        setSyntheticTrailingComments(node, getSyntheticTrailingComments(original));
        const emit = getOrCreateEmitNode(original);
        emit.leadingComments = undefined;
        emit.trailingComments = undefined;
        return node;
    }

    /**
     * Gets the constant value to emit for an expression.
     */
    export function getConstantValue(node: PropertyAccessExpression | ElementAccessExpression): string | number | undefined {
        const emitNode = node.emitNode;
        return emitNode && emitNode.constantValue;
    }

    /**
     * Sets the constant value to emit for an expression.
     */
    export function setConstantValue(node: PropertyAccessExpression | ElementAccessExpression, value: string | number): PropertyAccessExpression | ElementAccessExpression {
        const emitNode = getOrCreateEmitNode(node);
        emitNode.constantValue = value;
        return node;
    }

    /**
     * Adds an EmitHelper to a node.
     */
    export function addEmitHelper<T extends Node>(node: T, helper: EmitHelper): T {
        const emitNode = getOrCreateEmitNode(node);
        emitNode.helpers = append(emitNode.helpers, helper);
        return node;
    }

    /**
     * Add EmitHelpers to a node.
     */
    export function addEmitHelpers<T extends Node>(node: T, helpers: EmitHelper[] | undefined): T {
        if (some(helpers)) {
            const emitNode = getOrCreateEmitNode(node);
            for (const helper of helpers) {
                emitNode.helpers = appendIfUnique(emitNode.helpers, helper);
            }
        }
        return node;
    }

    /**
     * Removes an EmitHelper from a node.
     */
    export function removeEmitHelper(node: Node, helper: EmitHelper): boolean {
        const emitNode = node.emitNode;
        if (emitNode) {
            const helpers = emitNode.helpers;
            if (helpers) {
                return orderedRemoveItem(helpers, helper);
            }
        }
        return false;
    }

    /**
     * Gets the EmitHelpers of a node.
     */
    export function getEmitHelpers(node: Node): EmitHelper[] | undefined {
        const emitNode = node.emitNode;
        return emitNode && emitNode.helpers;
    }

    /**
     * Moves matching emit helpers from a source node to a target node.
     */
    export function moveEmitHelpers(source: Node, target: Node, predicate: (helper: EmitHelper) => boolean) {
        const sourceEmitNode = source.emitNode;
        const sourceEmitHelpers = sourceEmitNode && sourceEmitNode.helpers;
        if (!some(sourceEmitHelpers)) return;

        const targetEmitNode = getOrCreateEmitNode(target);
        let helpersRemoved = 0;
        for (let i = 0; i < sourceEmitHelpers.length; i++) {
            const helper = sourceEmitHelpers[i];
            if (predicate(helper)) {
                helpersRemoved++;
                targetEmitNode.helpers = appendIfUnique(targetEmitNode.helpers, helper);
            }
            else if (helpersRemoved > 0) {
                sourceEmitHelpers[i - helpersRemoved] = helper;
            }
        }

        if (helpersRemoved > 0) {
            sourceEmitHelpers.length -= helpersRemoved;
        }
    }

    /* @internal */
    export function compareEmitHelpers(x: EmitHelper, y: EmitHelper) {
        if (x === y) return Comparison.EqualTo;
        if (x.priority === y.priority) return Comparison.EqualTo;
        if (x.priority === undefined) return Comparison.GreaterThan;
        if (y.priority === undefined) return Comparison.LessThan;
        return compareValues(x.priority, y.priority);
    }

    export function setOriginalNode<T extends Node>(node: T, original: Node | undefined): T {
        node.original = original;
        if (original) {
            const emitNode = original.emitNode;
            if (emitNode) node.emitNode = mergeEmitNode(emitNode, node.emitNode);
        }
        return node;
    }

    function mergeEmitNode(sourceEmitNode: EmitNode, destEmitNode: EmitNode | undefined) {
        const {
            flags,
            leadingComments,
            trailingComments,
            commentRange,
            sourceMapRange,
            tokenSourceMapRanges,
            constantValue,
            helpers,
            startsOnNewLine,
        } = sourceEmitNode;
        if (!destEmitNode) destEmitNode = {} as EmitNode;
        // We are using `.slice()` here in case `destEmitNode.leadingComments` is pushed to later.
        if (leadingComments) destEmitNode.leadingComments = addRange(leadingComments.slice(), destEmitNode.leadingComments);
        if (trailingComments) destEmitNode.trailingComments = addRange(trailingComments.slice(), destEmitNode.trailingComments);
        if (flags) destEmitNode.flags = flags;
        if (commentRange) destEmitNode.commentRange = commentRange;
        if (sourceMapRange) destEmitNode.sourceMapRange = sourceMapRange;
        if (tokenSourceMapRanges) destEmitNode.tokenSourceMapRanges = mergeTokenSourceMapRanges(tokenSourceMapRanges, destEmitNode.tokenSourceMapRanges!);
        if (constantValue !== undefined) destEmitNode.constantValue = constantValue;
        if (helpers) destEmitNode.helpers = addRange(destEmitNode.helpers, helpers);
        if (startsOnNewLine !== undefined) destEmitNode.startsOnNewLine = startsOnNewLine;
        return destEmitNode;
    }

    function mergeTokenSourceMapRanges(sourceRanges: (TextRange | undefined)[], destRanges: (TextRange | undefined)[]) {
        if (!destRanges) destRanges = [];
        for (const key in sourceRanges) {
            destRanges[key] = sourceRanges[key];
        }
        return destRanges;
    }
}