fixAddMissingMember.ts

/* @internal */
namespace ts.codefix {
    const fixMissingMember = "fixMissingMember";
    const fixMissingProperties = "fixMissingProperties";
    const fixMissingAttributes = "fixMissingAttributes";
    const fixMissingFunctionDeclaration = "fixMissingFunctionDeclaration";

    const errorCodes = [
        Diagnostics.Property_0_does_not_exist_on_type_1.code,
        Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2.code,
        Diagnostics.Property_0_is_missing_in_type_1_but_required_in_type_2.code,
        Diagnostics.Type_0_is_missing_the_following_properties_from_type_1_Colon_2.code,
        Diagnostics.Type_0_is_missing_the_following_properties_from_type_1_Colon_2_and_3_more.code,
        Diagnostics.Argument_of_type_0_is_not_assignable_to_parameter_of_type_1.code,
        Diagnostics.Cannot_find_name_0.code
    ];

    enum InfoKind {
        TypeLikeDeclaration,
        Enum,
        Function,
        ObjectLiteral,
        JsxAttributes,
        Signature,
    }

    registerCodeFix({
        errorCodes,
        getCodeActions(context) {
            const typeChecker = context.program.getTypeChecker();
            const info = getInfo(context.sourceFile, context.span.start, context.errorCode, typeChecker, context.program);
            if (!info) {
                return undefined;
            }
            if (info.kind === InfoKind.ObjectLiteral) {
                const changes = textChanges.ChangeTracker.with(context, t => addObjectLiteralProperties(t, context, info));
                return [createCodeFixAction(fixMissingProperties, changes, Diagnostics.Add_missing_properties, fixMissingProperties, Diagnostics.Add_all_missing_properties)];
            }
            if (info.kind === InfoKind.JsxAttributes) {
                const changes = textChanges.ChangeTracker.with(context, t => addJsxAttributes(t, context, info));
                return [createCodeFixAction(fixMissingAttributes, changes, Diagnostics.Add_missing_attributes, fixMissingAttributes, Diagnostics.Add_all_missing_attributes)];
            }
            if (info.kind === InfoKind.Function || info.kind === InfoKind.Signature) {
                const changes = textChanges.ChangeTracker.with(context, t => addFunctionDeclaration(t, context, info));
                return [createCodeFixAction(fixMissingFunctionDeclaration, changes, [Diagnostics.Add_missing_function_declaration_0, info.token.text], fixMissingFunctionDeclaration, Diagnostics.Add_all_missing_function_declarations)];
            }
            if (info.kind === InfoKind.Enum) {
                const changes = textChanges.ChangeTracker.with(context, t => addEnumMemberDeclaration(t, context.program.getTypeChecker(), info));
                return [createCodeFixAction(fixMissingMember, changes, [Diagnostics.Add_missing_enum_member_0, info.token.text], fixMissingMember, Diagnostics.Add_all_missing_members)];
            }
            return concatenate(getActionsForMissingMethodDeclaration(context, info), getActionsForMissingMemberDeclaration(context, info));
        },
        fixIds: [fixMissingMember, fixMissingFunctionDeclaration, fixMissingProperties, fixMissingAttributes],
        getAllCodeActions: context => {
            const { program, fixId } = context;
            const checker = program.getTypeChecker();
            const seen = new Map<string, true>();
            const typeDeclToMembers = new Map<ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode, TypeLikeDeclarationInfo[]>();

            return createCombinedCodeActions(textChanges.ChangeTracker.with(context, changes => {
                eachDiagnostic(context, errorCodes, diag => {
                    const info = getInfo(diag.file, diag.start, diag.code, checker, context.program);
                    if (!info || !addToSeen(seen, getNodeId(info.parentDeclaration) + "#" + info.token.text)) {
                        return;
                    }
                    if (fixId === fixMissingFunctionDeclaration && (info.kind === InfoKind.Function || info.kind === InfoKind.Signature)) {
                        addFunctionDeclaration(changes, context, info);
                    }
                    else if (fixId === fixMissingProperties && info.kind === InfoKind.ObjectLiteral) {
                        addObjectLiteralProperties(changes, context, info);
                    }
                    else if (fixId === fixMissingAttributes && info.kind === InfoKind.JsxAttributes) {
                        addJsxAttributes(changes, context, info);
                    }
                    else {
                        if (info.kind === InfoKind.Enum) {
                            addEnumMemberDeclaration(changes, checker, info);
                        }
                        if (info.kind === InfoKind.TypeLikeDeclaration) {
                            const { parentDeclaration, token } = info;
                            const infos = getOrUpdate(typeDeclToMembers, parentDeclaration, () => []);
                            if (!infos.some(i => i.token.text === token.text)) {
                                infos.push(info);
                            }
                        }
                    }
                });

                typeDeclToMembers.forEach((infos, declaration) => {
                    const supers = isTypeLiteralNode(declaration) ? undefined : getAllSupers(declaration, checker);
                    for (const info of infos) {
                        // If some superclass added this property, don't add it again.
                        if (supers?.some(superClassOrInterface => {
                            const superInfos = typeDeclToMembers.get(superClassOrInterface);
                            return !!superInfos && superInfos.some(({ token }) => token.text === info.token.text);
                        })) continue;

                        const { parentDeclaration, declSourceFile, modifierFlags, token, call, isJSFile } = info;
                        // Always prefer to add a method declaration if possible.
                        if (call && !isPrivateIdentifier(token)) {
                            addMethodDeclaration(context, changes, call, token, modifierFlags & ModifierFlags.Static, parentDeclaration, declSourceFile);
                        }
                        else {
                            if (isJSFile && !isInterfaceDeclaration(parentDeclaration) && !isTypeLiteralNode(parentDeclaration)) {
                                addMissingMemberInJs(changes, declSourceFile, parentDeclaration, token, !!(modifierFlags & ModifierFlags.Static));
                            }
                            else {
                                const typeNode = getTypeNode(checker, parentDeclaration, token);
                                addPropertyDeclaration(changes, declSourceFile, parentDeclaration, token.text, typeNode, modifierFlags & ModifierFlags.Static);
                            }
                        }
                    }
                });
            }));
        },
    });

    type Info = TypeLikeDeclarationInfo | EnumInfo | FunctionInfo | ObjectLiteralInfo | JsxAttributesInfo | SignatureInfo;

    interface EnumInfo {
        readonly kind: InfoKind.Enum;
        readonly token: Identifier;
        readonly parentDeclaration: EnumDeclaration;
    }

    interface TypeLikeDeclarationInfo {
        readonly kind: InfoKind.TypeLikeDeclaration;
        readonly call: CallExpression | undefined;
        readonly token: Identifier | PrivateIdentifier;
        readonly modifierFlags: ModifierFlags;
        readonly parentDeclaration: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode;
        readonly declSourceFile: SourceFile;
        readonly isJSFile: boolean;
    }

    interface FunctionInfo {
        readonly kind: InfoKind.Function;
        readonly call: CallExpression;
        readonly token: Identifier;
        readonly sourceFile: SourceFile;
        readonly modifierFlags: ModifierFlags;
        readonly parentDeclaration: SourceFile | ModuleDeclaration | ReturnStatement;
    }

    interface ObjectLiteralInfo {
        readonly kind: InfoKind.ObjectLiteral;
        readonly token: Identifier;
        readonly properties: Symbol[];
        readonly parentDeclaration: ObjectLiteralExpression;
        readonly indentation?: number;
    }

    interface JsxAttributesInfo {
        readonly kind: InfoKind.JsxAttributes;
        readonly token: Identifier;
        readonly attributes: Symbol[];
        readonly parentDeclaration: JsxOpeningLikeElement;
    }

    interface SignatureInfo {
        readonly kind: InfoKind.Signature;
        readonly token: Identifier;
        readonly signature: Signature;
        readonly sourceFile: SourceFile;
        readonly parentDeclaration: Node;
    }

    function getInfo(sourceFile: SourceFile, tokenPos: number, errorCode: number, checker: TypeChecker, program: Program): Info | undefined {
        // The identifier of the missing property. eg:
        // this.missing = 1;
        //      ^^^^^^^
        const token = getTokenAtPosition(sourceFile, tokenPos);
        const parent = token.parent;

        if (errorCode === Diagnostics.Argument_of_type_0_is_not_assignable_to_parameter_of_type_1.code) {
            if (!(token.kind === SyntaxKind.OpenBraceToken && isObjectLiteralExpression(parent) && isCallExpression(parent.parent))) return undefined;

            const argIndex = findIndex(parent.parent.arguments, arg => arg === parent);
            if (argIndex < 0) return undefined;

            const signature = singleOrUndefined(checker.getSignaturesOfType(checker.getTypeAtLocation(parent.parent.expression), SignatureKind.Call));
            if (!(signature && signature.declaration && signature.parameters[argIndex])) return undefined;

            const param = signature.parameters[argIndex].valueDeclaration;
            if (!(param && isParameter(param) && isIdentifier(param.name))) return undefined;

            const properties = arrayFrom(checker.getUnmatchedProperties(checker.getTypeAtLocation(parent), checker.getParameterType(signature, argIndex), /* requireOptionalProperties */ false, /* matchDiscriminantProperties */ false));
            if (!length(properties)) return undefined;
            return { kind: InfoKind.ObjectLiteral, token: param.name, properties, parentDeclaration: parent };
        }

        if (!isMemberName(token)) return undefined;

        if (isIdentifier(token) && hasInitializer(parent) && parent.initializer && isObjectLiteralExpression(parent.initializer)) {
            const properties = arrayFrom(checker.getUnmatchedProperties(checker.getTypeAtLocation(parent.initializer), checker.getTypeAtLocation(token), /* requireOptionalProperties */ false, /* matchDiscriminantProperties */ false));
            if (!length(properties)) return undefined;

            return { kind: InfoKind.ObjectLiteral, token, properties, parentDeclaration: parent.initializer };
        }

        if (isIdentifier(token) && isJsxOpeningLikeElement(token.parent)) {
            const target = getEmitScriptTarget(program.getCompilerOptions());
            const attributes = getUnmatchedAttributes(checker, target, token.parent);
            if (!length(attributes)) return undefined;
            return { kind: InfoKind.JsxAttributes, token, attributes, parentDeclaration: token.parent };
        }

        if (isIdentifier(token)) {
            const type = checker.getContextualType(token);
            if (type && getObjectFlags(type) & ObjectFlags.Anonymous) {
                const signature = firstOrUndefined(checker.getSignaturesOfType(type, SignatureKind.Call));
                if (signature === undefined) return undefined;
                return { kind: InfoKind.Signature, token, signature, sourceFile, parentDeclaration: findScope(token) };
            }
            if (isCallExpression(parent) && parent.expression === token) {
                return { kind: InfoKind.Function, token, call: parent, sourceFile, modifierFlags: ModifierFlags.None, parentDeclaration: findScope(token) };
            }
        }

        if (!isPropertyAccessExpression(parent)) return undefined;

        const leftExpressionType = skipConstraint(checker.getTypeAtLocation(parent.expression));
        const symbol = leftExpressionType.symbol;
        if (!symbol || !symbol.declarations) return undefined;

        if (isIdentifier(token) && isCallExpression(parent.parent)) {
            const moduleDeclaration = find(symbol.declarations, isModuleDeclaration);
            const moduleDeclarationSourceFile = moduleDeclaration?.getSourceFile();
            if (moduleDeclaration && moduleDeclarationSourceFile && !isSourceFileFromLibrary(program, moduleDeclarationSourceFile)) {
                return { kind: InfoKind.Function, token, call: parent.parent, sourceFile, modifierFlags: ModifierFlags.Export, parentDeclaration: moduleDeclaration };
            }

            const moduleSourceFile = find(symbol.declarations, isSourceFile);
            if (sourceFile.commonJsModuleIndicator) return undefined;

            if (moduleSourceFile && !isSourceFileFromLibrary(program, moduleSourceFile)) {
                return { kind: InfoKind.Function, token, call: parent.parent, sourceFile: moduleSourceFile, modifierFlags: ModifierFlags.Export, parentDeclaration: moduleSourceFile };
            }
        }

        const classDeclaration = find(symbol.declarations, isClassLike);
        // Don't suggest adding private identifiers to anything other than a class.
        if (!classDeclaration && isPrivateIdentifier(token)) return undefined;

        // Prefer to change the class instead of the interface if they are merged
        const declaration = classDeclaration || find(symbol.declarations, d => isInterfaceDeclaration(d) || isTypeLiteralNode(d)) as InterfaceDeclaration | TypeLiteralNode | undefined;
        if (declaration && !isSourceFileFromLibrary(program, declaration.getSourceFile())) {
            const makeStatic = !isTypeLiteralNode(declaration) && ((leftExpressionType as TypeReference).target || leftExpressionType) !== checker.getDeclaredTypeOfSymbol(symbol);
            if (makeStatic && (isPrivateIdentifier(token) || isInterfaceDeclaration(declaration))) return undefined;

            const declSourceFile = declaration.getSourceFile();
            const modifierFlags = isTypeLiteralNode(declaration) ? ModifierFlags.None :
                (makeStatic ? ModifierFlags.Static : ModifierFlags.None) | (startsWithUnderscore(token.text) ? ModifierFlags.Private : ModifierFlags.None);
            const isJSFile = isSourceFileJS(declSourceFile);
            const call = tryCast(parent.parent, isCallExpression);
            return { kind: InfoKind.TypeLikeDeclaration, token, call, modifierFlags, parentDeclaration: declaration, declSourceFile, isJSFile };
        }

        const enumDeclaration = find(symbol.declarations, isEnumDeclaration);
        if (enumDeclaration && !isPrivateIdentifier(token) && !isSourceFileFromLibrary(program, enumDeclaration.getSourceFile())) {
            return { kind: InfoKind.Enum, token, parentDeclaration: enumDeclaration };
        }

        return undefined;
    }

    function isSourceFileFromLibrary(program: Program, node: SourceFile) {
        return program.isSourceFileFromExternalLibrary(node) || program.isSourceFileDefaultLibrary(node);
    }

    function getActionsForMissingMemberDeclaration(context: CodeFixContext, info: TypeLikeDeclarationInfo): CodeFixAction[] | undefined {
        return info.isJSFile ? singleElementArray(createActionForAddMissingMemberInJavascriptFile(context, info)) :
            createActionsForAddMissingMemberInTypeScriptFile(context, info);
    }

    function createActionForAddMissingMemberInJavascriptFile(context: CodeFixContext, { parentDeclaration, declSourceFile, modifierFlags, token }: TypeLikeDeclarationInfo): CodeFixAction | undefined {
        if (isInterfaceDeclaration(parentDeclaration) || isTypeLiteralNode(parentDeclaration)) {
            return undefined;
        }

        const changes = textChanges.ChangeTracker.with(context, t => addMissingMemberInJs(t, declSourceFile, parentDeclaration, token, !!(modifierFlags & ModifierFlags.Static)));
        if (changes.length === 0) {
            return undefined;
        }

        const diagnostic = modifierFlags & ModifierFlags.Static ? Diagnostics.Initialize_static_property_0 :
            isPrivateIdentifier(token) ? Diagnostics.Declare_a_private_field_named_0 : Diagnostics.Initialize_property_0_in_the_constructor;

        return createCodeFixAction(fixMissingMember, changes, [diagnostic, token.text], fixMissingMember, Diagnostics.Add_all_missing_members);
    }

    function addMissingMemberInJs(changeTracker: textChanges.ChangeTracker, sourceFile: SourceFile, classDeclaration: ClassLikeDeclaration, token: Identifier | PrivateIdentifier, makeStatic: boolean): void {
        const tokenName = token.text;
        if (makeStatic) {
            if (classDeclaration.kind === SyntaxKind.ClassExpression) {
                return;
            }
            const className = classDeclaration.name!.getText();
            const staticInitialization = initializePropertyToUndefined(factory.createIdentifier(className), tokenName);
            changeTracker.insertNodeAfter(sourceFile, classDeclaration, staticInitialization);
        }
        else if (isPrivateIdentifier(token)) {
            const property = factory.createPropertyDeclaration(
                /*modifiers*/ undefined,
                tokenName,
                /*questionToken*/ undefined,
                /*type*/ undefined,
                /*initializer*/ undefined);

            const lastProp = getNodeToInsertPropertyAfter(classDeclaration);
            if (lastProp) {
                changeTracker.insertNodeAfter(sourceFile, lastProp, property);
            }
            else {
                changeTracker.insertMemberAtStart(sourceFile, classDeclaration, property);
            }
        }
        else {
            const classConstructor = getFirstConstructorWithBody(classDeclaration);
            if (!classConstructor) {
                return;
            }
            const propertyInitialization = initializePropertyToUndefined(factory.createThis(), tokenName);
            changeTracker.insertNodeAtConstructorEnd(sourceFile, classConstructor, propertyInitialization);
        }
    }

    function initializePropertyToUndefined(obj: Expression, propertyName: string) {
        return factory.createExpressionStatement(factory.createAssignment(factory.createPropertyAccessExpression(obj, propertyName), createUndefined()));
    }

    function createActionsForAddMissingMemberInTypeScriptFile(context: CodeFixContext, { parentDeclaration, declSourceFile, modifierFlags, token }: TypeLikeDeclarationInfo): CodeFixAction[] | undefined {
        const memberName = token.text;
        const isStatic = modifierFlags & ModifierFlags.Static;
        const typeNode = getTypeNode(context.program.getTypeChecker(), parentDeclaration, token);
        const addPropertyDeclarationChanges = (modifierFlags: ModifierFlags) => textChanges.ChangeTracker.with(context, t => addPropertyDeclaration(t, declSourceFile, parentDeclaration, memberName, typeNode, modifierFlags));

        const actions = [createCodeFixAction(fixMissingMember, addPropertyDeclarationChanges(modifierFlags & ModifierFlags.Static), [isStatic ? Diagnostics.Declare_static_property_0 : Diagnostics.Declare_property_0, memberName], fixMissingMember, Diagnostics.Add_all_missing_members)];
        if (isStatic || isPrivateIdentifier(token)) {
            return actions;
        }

        if (modifierFlags & ModifierFlags.Private) {
            actions.unshift(createCodeFixActionWithoutFixAll(fixMissingMember, addPropertyDeclarationChanges(ModifierFlags.Private), [Diagnostics.Declare_private_property_0, memberName]));
        }

        actions.push(createAddIndexSignatureAction(context, declSourceFile, parentDeclaration, token.text, typeNode));
        return actions;
    }

    function getTypeNode(checker: TypeChecker, node: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode, token: Node) {
        let typeNode: TypeNode | undefined;
        if (token.parent.parent.kind === SyntaxKind.BinaryExpression) {
            const binaryExpression = token.parent.parent as BinaryExpression;
            const otherExpression = token.parent === binaryExpression.left ? binaryExpression.right : binaryExpression.left;
            const widenedType = checker.getWidenedType(checker.getBaseTypeOfLiteralType(checker.getTypeAtLocation(otherExpression)));
            typeNode = checker.typeToTypeNode(widenedType, node, NodeBuilderFlags.NoTruncation);
        }
        else {
            const contextualType = checker.getContextualType(token.parent as Expression);
            typeNode = contextualType ? checker.typeToTypeNode(contextualType, /*enclosingDeclaration*/ undefined, NodeBuilderFlags.NoTruncation) : undefined;
        }
        return typeNode || factory.createKeywordTypeNode(SyntaxKind.AnyKeyword);
    }

    function addPropertyDeclaration(changeTracker: textChanges.ChangeTracker, sourceFile: SourceFile, node: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode, tokenName: string, typeNode: TypeNode, modifierFlags: ModifierFlags): void {
        const modifiers = modifierFlags ? factory.createNodeArray(factory.createModifiersFromModifierFlags(modifierFlags)) : undefined;

        const property = isClassLike(node)
            ? factory.createPropertyDeclaration(modifiers, tokenName, /*questionToken*/ undefined, typeNode, /*initializer*/ undefined)
            : factory.createPropertySignature(/*modifiers*/ undefined, tokenName, /*questionToken*/ undefined, typeNode);

        const lastProp = getNodeToInsertPropertyAfter(node);
        if (lastProp) {
            changeTracker.insertNodeAfter(sourceFile, lastProp, property);
        }
        else {
            changeTracker.insertMemberAtStart(sourceFile, node, property);
        }
    }

    // Gets the last of the first run of PropertyDeclarations, or undefined if the class does not start with a PropertyDeclaration.
    function getNodeToInsertPropertyAfter(node: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode): PropertyDeclaration | undefined {
        let res: PropertyDeclaration | undefined;
        for (const member of node.members) {
            if (!isPropertyDeclaration(member)) break;
            res = member;
        }
        return res;
    }

    function createAddIndexSignatureAction(context: CodeFixContext, sourceFile: SourceFile, node: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode, tokenName: string, typeNode: TypeNode): CodeFixAction {
        // Index signatures cannot have the static modifier.
        const stringTypeNode = factory.createKeywordTypeNode(SyntaxKind.StringKeyword);
        const indexingParameter = factory.createParameterDeclaration(
            /*modifiers*/ undefined,
            /*dotDotDotToken*/ undefined,
            "x",
            /*questionToken*/ undefined,
            stringTypeNode,
            /*initializer*/ undefined);
        const indexSignature = factory.createIndexSignature(
            /*modifiers*/ undefined,
            [indexingParameter],
            typeNode);

        const changes = textChanges.ChangeTracker.with(context, t => t.insertMemberAtStart(sourceFile, node, indexSignature));
        // No fixId here because code-fix-all currently only works on adding individual named properties.
        return createCodeFixActionWithoutFixAll(fixMissingMember, changes, [Diagnostics.Add_index_signature_for_property_0, tokenName]);
    }

    function getActionsForMissingMethodDeclaration(context: CodeFixContext, info: TypeLikeDeclarationInfo): CodeFixAction[] | undefined {
        const { parentDeclaration, declSourceFile, modifierFlags, token, call } = info;
        if (call === undefined) {
            return undefined;
        }

        // Private methods are not implemented yet.
        if (isPrivateIdentifier(token)) {
            return undefined;
        }

        const methodName = token.text;
        const addMethodDeclarationChanges = (modifierFlags: ModifierFlags) => textChanges.ChangeTracker.with(context, t => addMethodDeclaration(context, t, call, token, modifierFlags, parentDeclaration, declSourceFile));
        const actions = [createCodeFixAction(fixMissingMember, addMethodDeclarationChanges(modifierFlags & ModifierFlags.Static), [modifierFlags & ModifierFlags.Static ? Diagnostics.Declare_static_method_0 : Diagnostics.Declare_method_0, methodName], fixMissingMember, Diagnostics.Add_all_missing_members)];
        if (modifierFlags & ModifierFlags.Private) {
            actions.unshift(createCodeFixActionWithoutFixAll(fixMissingMember, addMethodDeclarationChanges(ModifierFlags.Private), [Diagnostics.Declare_private_method_0, methodName]));
        }
        return actions;
    }

    function addMethodDeclaration(
        context: CodeFixContextBase,
        changes: textChanges.ChangeTracker,
        callExpression: CallExpression,
        name: Identifier,
        modifierFlags: ModifierFlags,
        parentDeclaration: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode,
        sourceFile: SourceFile,
    ): void {
        const importAdder = createImportAdder(sourceFile, context.program, context.preferences, context.host);
        const kind = isClassLike(parentDeclaration) ? SyntaxKind.MethodDeclaration : SyntaxKind.MethodSignature;
        const signatureDeclaration = createSignatureDeclarationFromCallExpression(kind, context, importAdder, callExpression, name, modifierFlags, parentDeclaration) as MethodDeclaration;
        const containingMethodDeclaration = tryGetContainingMethodDeclaration(parentDeclaration, callExpression);
        if (containingMethodDeclaration) {
            changes.insertNodeAfter(sourceFile, containingMethodDeclaration, signatureDeclaration);
        }
        else {
            changes.insertMemberAtStart(sourceFile, parentDeclaration, signatureDeclaration);
        }
        importAdder.writeFixes(changes);
    }

    function addEnumMemberDeclaration(changes: textChanges.ChangeTracker, checker: TypeChecker, { token, parentDeclaration }: EnumInfo) {
        /**
         * create initializer only literal enum that has string initializer.
         * value of initializer is a string literal that equal to name of enum member.
         * numeric enum or empty enum will not create initializer.
         */
        const hasStringInitializer = some(parentDeclaration.members, member => {
            const type = checker.getTypeAtLocation(member);
            return !!(type && type.flags & TypeFlags.StringLike);
        });

        const enumMember = factory.createEnumMember(token, hasStringInitializer ? factory.createStringLiteral(token.text) : undefined);
        changes.replaceNode(parentDeclaration.getSourceFile(), parentDeclaration, factory.updateEnumDeclaration(
            parentDeclaration,
            parentDeclaration.modifiers,
            parentDeclaration.name,
            concatenate(parentDeclaration.members, singleElementArray(enumMember))
        ), {
            leadingTriviaOption: textChanges.LeadingTriviaOption.IncludeAll,
            trailingTriviaOption: textChanges.TrailingTriviaOption.Exclude
        });
    }

    function addFunctionDeclaration(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: FunctionInfo | SignatureInfo) {
        const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
        const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
        const functionDeclaration = info.kind === InfoKind.Function
            ? createSignatureDeclarationFromCallExpression(SyntaxKind.FunctionDeclaration, context, importAdder, info.call, idText(info.token), info.modifierFlags, info.parentDeclaration)
            : createSignatureDeclarationFromSignature(SyntaxKind.FunctionDeclaration, context, quotePreference, info.signature, createStubbedBody(Diagnostics.Function_not_implemented.message, quotePreference), info.token, /*modifiers*/ undefined, /*optional*/ undefined, /*enclosingDeclaration*/ undefined, importAdder);
        if (functionDeclaration === undefined) {
            Debug.fail("fixMissingFunctionDeclaration codefix got unexpected error.");
        }

        isReturnStatement(info.parentDeclaration)
            ? changes.insertNodeBefore(info.sourceFile, info.parentDeclaration, functionDeclaration, /*blankLineBetween*/ true)
            : changes.insertNodeAtEndOfScope(info.sourceFile, info.parentDeclaration, functionDeclaration);
        importAdder.writeFixes(changes);
    }

    function addJsxAttributes(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: JsxAttributesInfo) {
        const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
        const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
        const checker = context.program.getTypeChecker();
        const jsxAttributesNode = info.parentDeclaration.attributes;
        const hasSpreadAttribute = some(jsxAttributesNode.properties, isJsxSpreadAttribute);
        const attrs = map(info.attributes, attr => {
            const value = tryGetValueFromType(context, checker, importAdder, quotePreference, checker.getTypeOfSymbol(attr), info.parentDeclaration);
            const name = factory.createIdentifier(attr.name);
            const jsxAttribute = factory.createJsxAttribute(name, factory.createJsxExpression(/*dotDotDotToken*/ undefined, value));
            // formattingScanner requires the Identifier to have a context for scanning attributes with "-" (data-foo).
            setParent(name, jsxAttribute);
            return jsxAttribute;
        });
        const jsxAttributes = factory.createJsxAttributes(hasSpreadAttribute ? [...attrs, ...jsxAttributesNode.properties] : [...jsxAttributesNode.properties, ...attrs]);
        const options = { prefix: jsxAttributesNode.pos === jsxAttributesNode.end ? " " : undefined };
        changes.replaceNode(context.sourceFile, jsxAttributesNode, jsxAttributes, options);
        importAdder.writeFixes(changes);
    }

    function addObjectLiteralProperties(changes: textChanges.ChangeTracker, context: CodeFixContextBase, info: ObjectLiteralInfo) {
        const importAdder = createImportAdder(context.sourceFile, context.program, context.preferences, context.host);
        const quotePreference = getQuotePreference(context.sourceFile, context.preferences);
        const target = getEmitScriptTarget(context.program.getCompilerOptions());
        const checker = context.program.getTypeChecker();
        const props = map(info.properties, prop => {
            const initializer = tryGetValueFromType(context, checker, importAdder, quotePreference, checker.getTypeOfSymbol(prop), info.parentDeclaration);
            return factory.createPropertyAssignment(createPropertyNameFromSymbol(prop, target, quotePreference, checker), initializer);
        });
        const options = {
            leadingTriviaOption: textChanges.LeadingTriviaOption.Exclude,
            trailingTriviaOption: textChanges.TrailingTriviaOption.Exclude,
            indentation: info.indentation
        };
        changes.replaceNode(context.sourceFile, info.parentDeclaration, factory.createObjectLiteralExpression([...info.parentDeclaration.properties, ...props], /*multiLine*/ true), options);
        importAdder.writeFixes(changes);
    }

    function tryGetValueFromType(context: CodeFixContextBase, checker: TypeChecker, importAdder: ImportAdder, quotePreference: QuotePreference, type: Type, enclosingDeclaration: Node | undefined): Expression {
        if (type.flags & TypeFlags.AnyOrUnknown) {
            return createUndefined();
        }
        if (type.flags & (TypeFlags.String | TypeFlags.TemplateLiteral)) {
            return factory.createStringLiteral("", /* isSingleQuote */ quotePreference === QuotePreference.Single);
        }
        if (type.flags & TypeFlags.Number) {
            return factory.createNumericLiteral(0);
        }
        if (type.flags & TypeFlags.BigInt) {
            return factory.createBigIntLiteral("0n");
        }
        if (type.flags & TypeFlags.Boolean) {
            return factory.createFalse();
        }
        if (type.flags & TypeFlags.EnumLike) {
            const enumMember = type.symbol.exports ? firstOrUndefined(arrayFrom(type.symbol.exports.values())) : type.symbol;
            const name = checker.symbolToExpression(type.symbol.parent ? type.symbol.parent : type.symbol, SymbolFlags.Value, /*enclosingDeclaration*/ undefined, /*flags*/ undefined);
            return enumMember === undefined || name === undefined ? factory.createNumericLiteral(0) : factory.createPropertyAccessExpression(name, checker.symbolToString(enumMember));
        }
        if (type.flags & TypeFlags.NumberLiteral) {
            return factory.createNumericLiteral((type as NumberLiteralType).value);
        }
        if (type.flags & TypeFlags.BigIntLiteral) {
            return factory.createBigIntLiteral((type as BigIntLiteralType).value);
        }
        if (type.flags & TypeFlags.StringLiteral) {
            return factory.createStringLiteral((type as StringLiteralType).value, /* isSingleQuote */ quotePreference === QuotePreference.Single);
        }
        if (type.flags & TypeFlags.BooleanLiteral) {
            return (type === checker.getFalseType() || type === checker.getFalseType(/*fresh*/ true)) ? factory.createFalse() : factory.createTrue();
        }
        if (type.flags & TypeFlags.Null) {
            return factory.createNull();
        }
        if (type.flags & TypeFlags.Union) {
            const expression = firstDefined((type as UnionType).types, t => tryGetValueFromType(context, checker, importAdder, quotePreference, t, enclosingDeclaration));
            return expression ?? createUndefined();
        }
        if (checker.isArrayLikeType(type)) {
            return factory.createArrayLiteralExpression();
        }
        if (isObjectLiteralType(type)) {
            const props = map(checker.getPropertiesOfType(type), prop => {
                const initializer = prop.valueDeclaration ? tryGetValueFromType(context, checker, importAdder, quotePreference, checker.getTypeAtLocation(prop.valueDeclaration), enclosingDeclaration) : createUndefined();
                return factory.createPropertyAssignment(prop.name, initializer);
            });
            return factory.createObjectLiteralExpression(props, /*multiLine*/ true);
        }
        if (getObjectFlags(type) & ObjectFlags.Anonymous) {
            const decl = find(type.symbol.declarations || emptyArray, or(isFunctionTypeNode, isMethodSignature, isMethodDeclaration));
            if (decl === undefined) return createUndefined();

            const signature = checker.getSignaturesOfType(type, SignatureKind.Call);
            if (signature === undefined) return createUndefined();

            const func = createSignatureDeclarationFromSignature(SyntaxKind.FunctionExpression, context, quotePreference, signature[0],
                createStubbedBody(Diagnostics.Function_not_implemented.message, quotePreference), /*name*/ undefined, /*modifiers*/ undefined, /*optional*/ undefined, /*enclosingDeclaration*/ enclosingDeclaration, importAdder) as FunctionExpression | undefined;
            return func ?? createUndefined();
        }
        if (getObjectFlags(type) & ObjectFlags.Class) {
            const classDeclaration = getClassLikeDeclarationOfSymbol(type.symbol);
            if (classDeclaration === undefined || hasAbstractModifier(classDeclaration)) return createUndefined();

            const constructorDeclaration = getFirstConstructorWithBody(classDeclaration);
            if (constructorDeclaration && length(constructorDeclaration.parameters)) return createUndefined();

            return factory.createNewExpression(factory.createIdentifier(type.symbol.name), /*typeArguments*/ undefined, /*argumentsArray*/ undefined);
        }
        return createUndefined();
    }

    function createUndefined() {
        return factory.createIdentifier("undefined");
    }

    function isObjectLiteralType(type: Type) {
        return (type.flags & TypeFlags.Object) &&
            ((getObjectFlags(type) & ObjectFlags.ObjectLiteral) || (type.symbol && tryCast(singleOrUndefined(type.symbol.declarations), isTypeLiteralNode)));
    }

    function getUnmatchedAttributes(checker: TypeChecker, target: ScriptTarget, source: JsxOpeningLikeElement) {
        const attrsType = checker.getContextualType(source.attributes);
        if (attrsType === undefined) return emptyArray;

        const targetProps = attrsType.getProperties();
        if (!length(targetProps)) return emptyArray;

        const seenNames = new Set<__String>();
        for (const sourceProp of source.attributes.properties) {
            if (isJsxAttribute(sourceProp)) {
                seenNames.add(sourceProp.name.escapedText);
            }
            if (isJsxSpreadAttribute(sourceProp)) {
                const type = checker.getTypeAtLocation(sourceProp.expression);
                for (const prop of type.getProperties()) {
                    seenNames.add(prop.escapedName);
                }
            }
        }
        return filter(targetProps, targetProp =>
            isIdentifierText(targetProp.name, target, LanguageVariant.JSX) && !((targetProp.flags & SymbolFlags.Optional || getCheckFlags(targetProp) & CheckFlags.Partial) || seenNames.has(targetProp.escapedName)));
    }

    function tryGetContainingMethodDeclaration(node: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode, callExpression: CallExpression) {
        if (isTypeLiteralNode(node)) {
            return undefined;
        }
        const declaration = findAncestor(callExpression, n => isMethodDeclaration(n) || isConstructorDeclaration(n));
        return declaration && declaration.parent === node ? declaration : undefined;
    }

    function createPropertyNameFromSymbol(symbol: Symbol, target: ScriptTarget, quotePreference: QuotePreference, checker: TypeChecker) {
        if (isTransientSymbol(symbol)) {
            const prop = checker.symbolToNode(symbol, SymbolFlags.Value, /*enclosingDeclaration*/ undefined, NodeBuilderFlags.AllowComputedProps);
            if (prop && isComputedPropertyName(prop)) {
                return prop;
            }
        }
        return createPropertyNameNodeForIdentifierOrLiteral(symbol.name, target, quotePreference === QuotePreference.Single);
    }

    function findScope(node: Node) {
        if (findAncestor(node, isJsxExpression)) {
            const returnStatement = findAncestor(node.parent, isReturnStatement);
            if (returnStatement) return returnStatement;
        }
        return getSourceFileOfNode(node);
    }
}