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node_modules/eslint/lib/linter/linter.js

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+/**
+ * @fileoverview Main Linter Class
+ * @author Gyandeep Singh
+ * @author aladdin-add
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const
+    path = require("path"),
+    eslintScope = require("eslint-scope"),
+    evk = require("eslint-visitor-keys"),
+    espree = require("espree"),
+    merge = require("lodash.merge"),
+    pkg = require("../../package.json"),
+    astUtils = require("../shared/ast-utils"),
+    {
+        directivesPattern
+    } = require("../shared/directives"),
+    {
+        Legacy: {
+            ConfigOps,
+            ConfigValidator,
+            environments: BuiltInEnvironments
+        }
+    } = require("@eslint/eslintrc/universal"),
+    Traverser = require("../shared/traverser"),
+    { SourceCode } = require("../source-code"),
+    CodePathAnalyzer = require("./code-path-analysis/code-path-analyzer"),
+    applyDisableDirectives = require("./apply-disable-directives"),
+    ConfigCommentParser = require("./config-comment-parser"),
+    NodeEventGenerator = require("./node-event-generator"),
+    createReportTranslator = require("./report-translator"),
+    Rules = require("./rules"),
+    createEmitter = require("./safe-emitter"),
+    SourceCodeFixer = require("./source-code-fixer"),
+    timing = require("./timing"),
+    ruleReplacements = require("../../conf/replacements.json");
+const { getRuleFromConfig } = require("../config/flat-config-helpers");
+const { FlatConfigArray } = require("../config/flat-config-array");
+const { RuleValidator } = require("../config/rule-validator");
+const { assertIsRuleOptions, assertIsRuleSeverity } = require("../config/flat-config-schema");
+const { normalizeSeverityToString } = require("../shared/severity");
+const debug = require("debug")("eslint:linter");
+const MAX_AUTOFIX_PASSES = 10;
+const DEFAULT_PARSER_NAME = "espree";
+const DEFAULT_ECMA_VERSION = 5;
+const commentParser = new ConfigCommentParser();
+const DEFAULT_ERROR_LOC = { start: { line: 1, column: 0 }, end: { line: 1, column: 1 } };
+const parserSymbol = Symbol.for("eslint.RuleTester.parser");
+
+//------------------------------------------------------------------------------
+// Typedefs
+//------------------------------------------------------------------------------
+
+/** @typedef {InstanceType<import("../cli-engine/config-array").ConfigArray>} ConfigArray */
+/** @typedef {InstanceType<import("../cli-engine/config-array").ExtractedConfig>} ExtractedConfig */
+/** @typedef {import("../shared/types").ConfigData} ConfigData */
+/** @typedef {import("../shared/types").Environment} Environment */
+/** @typedef {import("../shared/types").GlobalConf} GlobalConf */
+/** @typedef {import("../shared/types").LintMessage} LintMessage */
+/** @typedef {import("../shared/types").SuppressedLintMessage} SuppressedLintMessage */
+/** @typedef {import("../shared/types").ParserOptions} ParserOptions */
+/** @typedef {import("../shared/types").LanguageOptions} LanguageOptions */
+/** @typedef {import("../shared/types").Processor} Processor */
+/** @typedef {import("../shared/types").Rule} Rule */
+
+/* eslint-disable jsdoc/valid-types -- https://github.com/jsdoc-type-pratt-parser/jsdoc-type-pratt-parser/issues/4#issuecomment-778805577 */
+/**
+ * @template T
+ * @typedef {{ [P in keyof T]-?: T[P] }} Required
+ */
+/* eslint-enable jsdoc/valid-types -- https://github.com/jsdoc-type-pratt-parser/jsdoc-type-pratt-parser/issues/4#issuecomment-778805577 */
+
+/**
+ * @typedef {Object} DisableDirective
+ * @property {("disable"|"enable"|"disable-line"|"disable-next-line")} type Type of directive
+ * @property {number} line The line number
+ * @property {number} column The column number
+ * @property {(string|null)} ruleId The rule ID
+ * @property {string} justification The justification of directive
+ */
+
+/**
+ * The private data for `Linter` instance.
+ * @typedef {Object} LinterInternalSlots
+ * @property {ConfigArray|null} lastConfigArray The `ConfigArray` instance that the last `verify()` call used.
+ * @property {SourceCode|null} lastSourceCode The `SourceCode` instance that the last `verify()` call used.
+ * @property {SuppressedLintMessage[]} lastSuppressedMessages The `SuppressedLintMessage[]` instance that the last `verify()` call produced.
+ * @property {Map<string, Parser>} parserMap The loaded parsers.
+ * @property {Rules} ruleMap The loaded rules.
+ */
+
+/**
+ * @typedef {Object} VerifyOptions
+ * @property {boolean} [allowInlineConfig] Allow/disallow inline comments' ability
+ *      to change config once it is set. Defaults to true if not supplied.
+ *      Useful if you want to validate JS without comments overriding rules.
+ * @property {boolean} [disableFixes] if `true` then the linter doesn't make `fix`
+ *      properties into the lint result.
+ * @property {string} [filename] the filename of the source code.
+ * @property {boolean | "off" | "warn" | "error"} [reportUnusedDisableDirectives] Adds reported errors for
+ *      unused `eslint-disable` directives.
+ */
+
+/**
+ * @typedef {Object} ProcessorOptions
+ * @property {(filename:string, text:string) => boolean} [filterCodeBlock] the
+ *      predicate function that selects adopt code blocks.
+ * @property {Processor.postprocess} [postprocess] postprocessor for report
+ *      messages. If provided, this should accept an array of the message lists
+ *      for each code block returned from the preprocessor, apply a mapping to
+ *      the messages as appropriate, and return a one-dimensional array of
+ *      messages.
+ * @property {Processor.preprocess} [preprocess] preprocessor for source text.
+ *      If provided, this should accept a string of source text, and return an
+ *      array of code blocks to lint.
+ */
+
+/**
+ * @typedef {Object} FixOptions
+ * @property {boolean | ((message: LintMessage) => boolean)} [fix] Determines
+ *      whether fixes should be applied.
+ */
+
+/**
+ * @typedef {Object} InternalOptions
+ * @property {string | null} warnInlineConfig The config name what `noInlineConfig` setting came from. If `noInlineConfig` setting didn't exist, this is null. If this is a config name, then the linter warns directive comments.
+ * @property {"off" | "warn" | "error"} reportUnusedDisableDirectives (boolean values were normalized)
+ */
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Determines if a given object is Espree.
+ * @param {Object} parser The parser to check.
+ * @returns {boolean} True if the parser is Espree or false if not.
+ */
+function isEspree(parser) {
+    return !!(parser === espree || parser[parserSymbol] === espree);
+}
+
+/**
+ * Ensures that variables representing built-in properties of the Global Object,
+ * and any globals declared by special block comments, are present in the global
+ * scope.
+ * @param {Scope} globalScope The global scope.
+ * @param {Object} configGlobals The globals declared in configuration
+ * @param {{exportedVariables: Object, enabledGlobals: Object}} commentDirectives Directives from comment configuration
+ * @returns {void}
+ */
+function addDeclaredGlobals(globalScope, configGlobals, { exportedVariables, enabledGlobals }) {
+
+    // Define configured global variables.
+    for (const id of new Set([...Object.keys(configGlobals), ...Object.keys(enabledGlobals)])) {
+
+        /*
+         * `ConfigOps.normalizeConfigGlobal` will throw an error if a configured global value is invalid. However, these errors would
+         * typically be caught when validating a config anyway (validity for inline global comments is checked separately).
+         */
+        const configValue = configGlobals[id] === void 0 ? void 0 : ConfigOps.normalizeConfigGlobal(configGlobals[id]);
+        const commentValue = enabledGlobals[id] && enabledGlobals[id].value;
+        const value = commentValue || configValue;
+        const sourceComments = enabledGlobals[id] && enabledGlobals[id].comments;
+
+        if (value === "off") {
+            continue;
+        }
+
+        let variable = globalScope.set.get(id);
+
+        if (!variable) {
+            variable = new eslintScope.Variable(id, globalScope);
+
+            globalScope.variables.push(variable);
+            globalScope.set.set(id, variable);
+        }
+
+        variable.eslintImplicitGlobalSetting = configValue;
+        variable.eslintExplicitGlobal = sourceComments !== void 0;
+        variable.eslintExplicitGlobalComments = sourceComments;
+        variable.writeable = (value === "writable");
+    }
+
+    // mark all exported variables as such
+    Object.keys(exportedVariables).forEach(name => {
+        const variable = globalScope.set.get(name);
+
+        if (variable) {
+            variable.eslintUsed = true;
+            variable.eslintExported = true;
+        }
+    });
+
+    /*
+     * "through" contains all references which definitions cannot be found.
+     * Since we augment the global scope using configuration, we need to update
+     * references and remove the ones that were added by configuration.
+     */
+    globalScope.through = globalScope.through.filter(reference => {
+        const name = reference.identifier.name;
+        const variable = globalScope.set.get(name);
+
+        if (variable) {
+
+            /*
+             * Links the variable and the reference.
+             * And this reference is removed from `Scope#through`.
+             */
+            reference.resolved = variable;
+            variable.references.push(reference);
+
+            return false;
+        }
+
+        return true;
+    });
+}
+
+/**
+ * creates a missing-rule message.
+ * @param {string} ruleId the ruleId to create
+ * @returns {string} created error message
+ * @private
+ */
+function createMissingRuleMessage(ruleId) {
+    return Object.prototype.hasOwnProperty.call(ruleReplacements.rules, ruleId)
+        ? `Rule '${ruleId}' was removed and replaced by: ${ruleReplacements.rules[ruleId].join(", ")}`
+        : `Definition for rule '${ruleId}' was not found.`;
+}
+
+/**
+ * creates a linting problem
+ * @param {Object} options to create linting error
+ * @param {string} [options.ruleId] the ruleId to report
+ * @param {Object} [options.loc] the loc to report
+ * @param {string} [options.message] the error message to report
+ * @param {string} [options.severity] the error message to report
+ * @returns {LintMessage} created problem, returns a missing-rule problem if only provided ruleId.
+ * @private
+ */
+function createLintingProblem(options) {
+    const {
+        ruleId = null,
+        loc = DEFAULT_ERROR_LOC,
+        message = createMissingRuleMessage(options.ruleId),
+        severity = 2
+    } = options;
+
+    return {
+        ruleId,
+        message,
+        line: loc.start.line,
+        column: loc.start.column + 1,
+        endLine: loc.end.line,
+        endColumn: loc.end.column + 1,
+        severity,
+        nodeType: null
+    };
+}
+
+/**
+ * Creates a collection of disable directives from a comment
+ * @param {Object} options to create disable directives
+ * @param {("disable"|"enable"|"disable-line"|"disable-next-line")} options.type The type of directive comment
+ * @param {token} options.commentToken The Comment token
+ * @param {string} options.value The value after the directive in the comment
+ * comment specified no specific rules, so it applies to all rules (e.g. `eslint-disable`)
+ * @param {string} options.justification The justification of the directive
+ * @param {function(string): {create: Function}} options.ruleMapper A map from rule IDs to defined rules
+ * @returns {Object} Directives and problems from the comment
+ */
+function createDisableDirectives(options) {
+    const { commentToken, type, value, justification, ruleMapper } = options;
+    const ruleIds = Object.keys(commentParser.parseListConfig(value));
+    const directiveRules = ruleIds.length ? ruleIds : [null];
+    const result = {
+        directives: [], // valid disable directives
+        directiveProblems: [] // problems in directives
+    };
+
+    const parentComment = { commentToken, ruleIds };
+
+    for (const ruleId of directiveRules) {
+
+        // push to directives, if the rule is defined(including null, e.g. /*eslint enable*/)
+        if (ruleId === null || !!ruleMapper(ruleId)) {
+            if (type === "disable-next-line") {
+                result.directives.push({
+                    parentComment,
+                    type,
+                    line: commentToken.loc.end.line,
+                    column: commentToken.loc.end.column + 1,
+                    ruleId,
+                    justification
+                });
+            } else {
+                result.directives.push({
+                    parentComment,
+                    type,
+                    line: commentToken.loc.start.line,
+                    column: commentToken.loc.start.column + 1,
+                    ruleId,
+                    justification
+                });
+            }
+        } else {
+            result.directiveProblems.push(createLintingProblem({ ruleId, loc: commentToken.loc }));
+        }
+    }
+    return result;
+}
+
+/**
+ * Parses comments in file to extract file-specific config of rules, globals
+ * and environments and merges them with global config; also code blocks
+ * where reporting is disabled or enabled and merges them with reporting config.
+ * @param {SourceCode} sourceCode The SourceCode object to get comments from.
+ * @param {function(string): {create: Function}} ruleMapper A map from rule IDs to defined rules
+ * @param {string|null} warnInlineConfig If a string then it should warn directive comments as disabled. The string value is the config name what the setting came from.
+ * @returns {{configuredRules: Object, enabledGlobals: {value:string,comment:Token}[], exportedVariables: Object, problems: LintMessage[], disableDirectives: DisableDirective[]}}
+ * A collection of the directive comments that were found, along with any problems that occurred when parsing
+ */
+function getDirectiveComments(sourceCode, ruleMapper, warnInlineConfig) {
+    const configuredRules = {};
+    const enabledGlobals = Object.create(null);
+    const exportedVariables = {};
+    const problems = [];
+    const disableDirectives = [];
+    const validator = new ConfigValidator({
+        builtInRules: Rules
+    });
+
+    sourceCode.getInlineConfigNodes().filter(token => token.type !== "Shebang").forEach(comment => {
+        const { directivePart, justificationPart } = commentParser.extractDirectiveComment(comment.value);
+
+        const match = directivesPattern.exec(directivePart);
+
+        if (!match) {
+            return;
+        }
+        const directiveText = match[1];
+        const lineCommentSupported = /^eslint-disable-(next-)?line$/u.test(directiveText);
+
+        if (comment.type === "Line" && !lineCommentSupported) {
+            return;
+        }
+
+        if (warnInlineConfig) {
+            const kind = comment.type === "Block" ? `/*${directiveText}*/` : `//${directiveText}`;
+
+            problems.push(createLintingProblem({
+                ruleId: null,
+                message: `'${kind}' has no effect because you have 'noInlineConfig' setting in ${warnInlineConfig}.`,
+                loc: comment.loc,
+                severity: 1
+            }));
+            return;
+        }
+
+        if (directiveText === "eslint-disable-line" && comment.loc.start.line !== comment.loc.end.line) {
+            const message = `${directiveText} comment should not span multiple lines.`;
+
+            problems.push(createLintingProblem({
+                ruleId: null,
+                message,
+                loc: comment.loc
+            }));
+            return;
+        }
+
+        const directiveValue = directivePart.slice(match.index + directiveText.length);
+
+        switch (directiveText) {
+            case "eslint-disable":
+            case "eslint-enable":
+            case "eslint-disable-next-line":
+            case "eslint-disable-line": {
+                const directiveType = directiveText.slice("eslint-".length);
+                const options = { commentToken: comment, type: directiveType, value: directiveValue, justification: justificationPart, ruleMapper };
+                const { directives, directiveProblems } = createDisableDirectives(options);
+
+                disableDirectives.push(...directives);
+                problems.push(...directiveProblems);
+                break;
+            }
+
+            case "exported":
+                Object.assign(exportedVariables, commentParser.parseStringConfig(directiveValue, comment));
+                break;
+
+            case "globals":
+            case "global":
+                for (const [id, { value }] of Object.entries(commentParser.parseStringConfig(directiveValue, comment))) {
+                    let normalizedValue;
+
+                    try {
+                        normalizedValue = ConfigOps.normalizeConfigGlobal(value);
+                    } catch (err) {
+                        problems.push(createLintingProblem({
+                            ruleId: null,
+                            loc: comment.loc,
+                            message: err.message
+                        }));
+                        continue;
+                    }
+
+                    if (enabledGlobals[id]) {
+                        enabledGlobals[id].comments.push(comment);
+                        enabledGlobals[id].value = normalizedValue;
+                    } else {
+                        enabledGlobals[id] = {
+                            comments: [comment],
+                            value: normalizedValue
+                        };
+                    }
+                }
+                break;
+
+            case "eslint": {
+                const parseResult = commentParser.parseJsonConfig(directiveValue, comment.loc);
+
+                if (parseResult.success) {
+                    Object.keys(parseResult.config).forEach(name => {
+                        const rule = ruleMapper(name);
+                        const ruleValue = parseResult.config[name];
+
+                        if (!rule) {
+                            problems.push(createLintingProblem({ ruleId: name, loc: comment.loc }));
+                            return;
+                        }
+
+                        try {
+                            validator.validateRuleOptions(rule, name, ruleValue);
+                        } catch (err) {
+                            problems.push(createLintingProblem({
+                                ruleId: name,
+                                message: err.message,
+                                loc: comment.loc
+                            }));
+
+                            // do not apply the config, if found invalid options.
+                            return;
+                        }
+
+                        configuredRules[name] = ruleValue;
+                    });
+                } else {
+                    problems.push(parseResult.error);
+                }
+
+                break;
+            }
+
+            // no default
+        }
+    });
+
+    return {
+        configuredRules,
+        enabledGlobals,
+        exportedVariables,
+        problems,
+        disableDirectives
+    };
+}
+
+/**
+ * Parses comments in file to extract disable directives.
+ * @param {SourceCode} sourceCode The SourceCode object to get comments from.
+ * @param {function(string): {create: Function}} ruleMapper A map from rule IDs to defined rules
+ * @returns {{problems: LintMessage[], disableDirectives: DisableDirective[]}}
+ * A collection of the directive comments that were found, along with any problems that occurred when parsing
+ */
+function getDirectiveCommentsForFlatConfig(sourceCode, ruleMapper) {
+    const problems = [];
+    const disableDirectives = [];
+
+    sourceCode.getInlineConfigNodes().filter(token => token.type !== "Shebang").forEach(comment => {
+        const { directivePart, justificationPart } = commentParser.extractDirectiveComment(comment.value);
+
+        const match = directivesPattern.exec(directivePart);
+
+        if (!match) {
+            return;
+        }
+        const directiveText = match[1];
+        const lineCommentSupported = /^eslint-disable-(next-)?line$/u.test(directiveText);
+
+        if (comment.type === "Line" && !lineCommentSupported) {
+            return;
+        }
+
+        if (directiveText === "eslint-disable-line" && comment.loc.start.line !== comment.loc.end.line) {
+            const message = `${directiveText} comment should not span multiple lines.`;
+
+            problems.push(createLintingProblem({
+                ruleId: null,
+                message,
+                loc: comment.loc
+            }));
+            return;
+        }
+
+        const directiveValue = directivePart.slice(match.index + directiveText.length);
+
+        switch (directiveText) {
+            case "eslint-disable":
+            case "eslint-enable":
+            case "eslint-disable-next-line":
+            case "eslint-disable-line": {
+                const directiveType = directiveText.slice("eslint-".length);
+                const options = { commentToken: comment, type: directiveType, value: directiveValue, justification: justificationPart, ruleMapper };
+                const { directives, directiveProblems } = createDisableDirectives(options);
+
+                disableDirectives.push(...directives);
+                problems.push(...directiveProblems);
+                break;
+            }
+
+            // no default
+        }
+    });
+
+    return {
+        problems,
+        disableDirectives
+    };
+}
+
+/**
+ * Normalize ECMAScript version from the initial config
+ * @param {Parser} parser The parser which uses this options.
+ * @param {number} ecmaVersion ECMAScript version from the initial config
+ * @returns {number} normalized ECMAScript version
+ */
+function normalizeEcmaVersion(parser, ecmaVersion) {
+
+    if (isEspree(parser)) {
+        if (ecmaVersion === "latest") {
+            return espree.latestEcmaVersion;
+        }
+    }
+
+    /*
+     * Calculate ECMAScript edition number from official year version starting with
+     * ES2015, which corresponds with ES6 (or a difference of 2009).
+     */
+    return ecmaVersion >= 2015 ? ecmaVersion - 2009 : ecmaVersion;
+}
+
+/**
+ * Normalize ECMAScript version from the initial config into languageOptions (year)
+ * format.
+ * @param {any} [ecmaVersion] ECMAScript version from the initial config
+ * @returns {number} normalized ECMAScript version
+ */
+function normalizeEcmaVersionForLanguageOptions(ecmaVersion) {
+
+    switch (ecmaVersion) {
+        case 3:
+            return 3;
+
+        // void 0 = no ecmaVersion specified so use the default
+        case 5:
+        case void 0:
+            return 5;
+
+        default:
+            if (typeof ecmaVersion === "number") {
+                return ecmaVersion >= 2015 ? ecmaVersion : ecmaVersion + 2009;
+            }
+    }
+
+    /*
+     * We default to the latest supported ecmaVersion for everything else.
+     * Remember, this is for languageOptions.ecmaVersion, which sets the version
+     * that is used for a number of processes inside of ESLint. It's normally
+     * safe to assume people want the latest unless otherwise specified.
+     */
+    return espree.latestEcmaVersion + 2009;
+}
+
+const eslintEnvPattern = /\/\*\s*eslint-env\s(.+?)(?:\*\/|$)/gsu;
+
+/**
+ * Checks whether or not there is a comment which has "eslint-env *" in a given text.
+ * @param {string} text A source code text to check.
+ * @returns {Object|null} A result of parseListConfig() with "eslint-env *" comment.
+ */
+function findEslintEnv(text) {
+    let match, retv;
+
+    eslintEnvPattern.lastIndex = 0;
+
+    while ((match = eslintEnvPattern.exec(text)) !== null) {
+        if (match[0].endsWith("*/")) {
+            retv = Object.assign(
+                retv || {},
+                commentParser.parseListConfig(commentParser.extractDirectiveComment(match[1]).directivePart)
+            );
+        }
+    }
+
+    return retv;
+}
+
+/**
+ * Convert "/path/to/<text>" to "<text>".
+ * `CLIEngine#executeOnText()` method gives "/path/to/<text>" if the filename
+ * was omitted because `configArray.extractConfig()` requires an absolute path.
+ * But the linter should pass `<text>` to `RuleContext#filename` in that
+ * case.
+ * Also, code blocks can have their virtual filename. If the parent filename was
+ * `<text>`, the virtual filename is `<text>/0_foo.js` or something like (i.e.,
+ * it's not an absolute path).
+ * @param {string} filename The filename to normalize.
+ * @returns {string} The normalized filename.
+ */
+function normalizeFilename(filename) {
+    const parts = filename.split(path.sep);
+    const index = parts.lastIndexOf("<text>");
+
+    return index === -1 ? filename : parts.slice(index).join(path.sep);
+}
+
+/**
+ * Normalizes the possible options for `linter.verify` and `linter.verifyAndFix` to a
+ * consistent shape.
+ * @param {VerifyOptions} providedOptions Options
+ * @param {ConfigData} config Config.
+ * @returns {Required<VerifyOptions> & InternalOptions} Normalized options
+ */
+function normalizeVerifyOptions(providedOptions, config) {
+
+    const linterOptions = config.linterOptions || config;
+
+    // .noInlineConfig for eslintrc, .linterOptions.noInlineConfig for flat
+    const disableInlineConfig = linterOptions.noInlineConfig === true;
+    const ignoreInlineConfig = providedOptions.allowInlineConfig === false;
+    const configNameOfNoInlineConfig = config.configNameOfNoInlineConfig
+        ? ` (${config.configNameOfNoInlineConfig})`
+        : "";
+
+    let reportUnusedDisableDirectives = providedOptions.reportUnusedDisableDirectives;
+
+    if (typeof reportUnusedDisableDirectives === "boolean") {
+        reportUnusedDisableDirectives = reportUnusedDisableDirectives ? "error" : "off";
+    }
+    if (typeof reportUnusedDisableDirectives !== "string") {
+        if (typeof linterOptions.reportUnusedDisableDirectives === "boolean") {
+            reportUnusedDisableDirectives = linterOptions.reportUnusedDisableDirectives ? "warn" : "off";
+        } else {
+            reportUnusedDisableDirectives = linterOptions.reportUnusedDisableDirectives === void 0 ? "off" : normalizeSeverityToString(linterOptions.reportUnusedDisableDirectives);
+        }
+    }
+
+    return {
+        filename: normalizeFilename(providedOptions.filename || "<input>"),
+        allowInlineConfig: !ignoreInlineConfig,
+        warnInlineConfig: disableInlineConfig && !ignoreInlineConfig
+            ? `your config${configNameOfNoInlineConfig}`
+            : null,
+        reportUnusedDisableDirectives,
+        disableFixes: Boolean(providedOptions.disableFixes)
+    };
+}
+
+/**
+ * Combines the provided parserOptions with the options from environments
+ * @param {Parser} parser The parser which uses this options.
+ * @param {ParserOptions} providedOptions The provided 'parserOptions' key in a config
+ * @param {Environment[]} enabledEnvironments The environments enabled in configuration and with inline comments
+ * @returns {ParserOptions} Resulting parser options after merge
+ */
+function resolveParserOptions(parser, providedOptions, enabledEnvironments) {
+
+    const parserOptionsFromEnv = enabledEnvironments
+        .filter(env => env.parserOptions)
+        .reduce((parserOptions, env) => merge(parserOptions, env.parserOptions), {});
+    const mergedParserOptions = merge(parserOptionsFromEnv, providedOptions || {});
+    const isModule = mergedParserOptions.sourceType === "module";
+
+    if (isModule) {
+
+        /*
+         * can't have global return inside of modules
+         * TODO: espree validate parserOptions.globalReturn when sourceType is setting to module.(@aladdin-add)
+         */
+        mergedParserOptions.ecmaFeatures = Object.assign({}, mergedParserOptions.ecmaFeatures, { globalReturn: false });
+    }
+
+    mergedParserOptions.ecmaVersion = normalizeEcmaVersion(parser, mergedParserOptions.ecmaVersion);
+
+    return mergedParserOptions;
+}
+
+/**
+ * Converts parserOptions to languageOptions for backwards compatibility with eslintrc.
+ * @param {ConfigData} config Config object.
+ * @param {Object} config.globals Global variable definitions.
+ * @param {Parser} config.parser The parser to use.
+ * @param {ParserOptions} config.parserOptions The parserOptions to use.
+ * @returns {LanguageOptions} The languageOptions equivalent.
+ */
+function createLanguageOptions({ globals: configuredGlobals, parser, parserOptions }) {
+
+    const {
+        ecmaVersion,
+        sourceType
+    } = parserOptions;
+
+    return {
+        globals: configuredGlobals,
+        ecmaVersion: normalizeEcmaVersionForLanguageOptions(ecmaVersion),
+        sourceType,
+        parser,
+        parserOptions
+    };
+}
+
+/**
+ * Combines the provided globals object with the globals from environments
+ * @param {Record<string, GlobalConf>} providedGlobals The 'globals' key in a config
+ * @param {Environment[]} enabledEnvironments The environments enabled in configuration and with inline comments
+ * @returns {Record<string, GlobalConf>} The resolved globals object
+ */
+function resolveGlobals(providedGlobals, enabledEnvironments) {
+    return Object.assign(
+        {},
+        ...enabledEnvironments.filter(env => env.globals).map(env => env.globals),
+        providedGlobals
+    );
+}
+
+/**
+ * Strips Unicode BOM from a given text.
+ * @param {string} text A text to strip.
+ * @returns {string} The stripped text.
+ */
+function stripUnicodeBOM(text) {
+
+    /*
+     * Check Unicode BOM.
+     * In JavaScript, string data is stored as UTF-16, so BOM is 0xFEFF.
+     * http://www.ecma-international.org/ecma-262/6.0/#sec-unicode-format-control-characters
+     */
+    if (text.charCodeAt(0) === 0xFEFF) {
+        return text.slice(1);
+    }
+    return text;
+}
+
+/**
+ * Get the options for a rule (not including severity), if any
+ * @param {Array|number} ruleConfig rule configuration
+ * @returns {Array} of rule options, empty Array if none
+ */
+function getRuleOptions(ruleConfig) {
+    if (Array.isArray(ruleConfig)) {
+        return ruleConfig.slice(1);
+    }
+    return [];
+
+}
+
+/**
+ * Analyze scope of the given AST.
+ * @param {ASTNode} ast The `Program` node to analyze.
+ * @param {LanguageOptions} languageOptions The parser options.
+ * @param {Record<string, string[]>} visitorKeys The visitor keys.
+ * @returns {ScopeManager} The analysis result.
+ */
+function analyzeScope(ast, languageOptions, visitorKeys) {
+    const parserOptions = languageOptions.parserOptions;
+    const ecmaFeatures = parserOptions.ecmaFeatures || {};
+    const ecmaVersion = languageOptions.ecmaVersion || DEFAULT_ECMA_VERSION;
+
+    return eslintScope.analyze(ast, {
+        ignoreEval: true,
+        nodejsScope: ecmaFeatures.globalReturn,
+        impliedStrict: ecmaFeatures.impliedStrict,
+        ecmaVersion: typeof ecmaVersion === "number" ? ecmaVersion : 6,
+        sourceType: languageOptions.sourceType || "script",
+        childVisitorKeys: visitorKeys || evk.KEYS,
+        fallback: Traverser.getKeys
+    });
+}
+
+/**
+ * Parses text into an AST. Moved out here because the try-catch prevents
+ * optimization of functions, so it's best to keep the try-catch as isolated
+ * as possible
+ * @param {string} text The text to parse.
+ * @param {LanguageOptions} languageOptions Options to pass to the parser
+ * @param {string} filePath The path to the file being parsed.
+ * @returns {{success: false, error: LintMessage}|{success: true, sourceCode: SourceCode}}
+ * An object containing the AST and parser services if parsing was successful, or the error if parsing failed
+ * @private
+ */
+function parse(text, languageOptions, filePath) {
+    const textToParse = stripUnicodeBOM(text).replace(astUtils.shebangPattern, (match, captured) => `//${captured}`);
+    const { ecmaVersion, sourceType, parser } = languageOptions;
+    const parserOptions = Object.assign(
+        { ecmaVersion, sourceType },
+        languageOptions.parserOptions,
+        {
+            loc: true,
+            range: true,
+            raw: true,
+            tokens: true,
+            comment: true,
+            eslintVisitorKeys: true,
+            eslintScopeManager: true,
+            filePath
+        }
+    );
+
+    /*
+     * Check for parsing errors first. If there's a parsing error, nothing
+     * else can happen. However, a parsing error does not throw an error
+     * from this method - it's just considered a fatal error message, a
+     * problem that ESLint identified just like any other.
+     */
+    try {
+        debug("Parsing:", filePath);
+        const parseResult = (typeof parser.parseForESLint === "function")
+            ? parser.parseForESLint(textToParse, parserOptions)
+            : { ast: parser.parse(textToParse, parserOptions) };
+
+        debug("Parsing successful:", filePath);
+        const ast = parseResult.ast;
+        const parserServices = parseResult.services || {};
+        const visitorKeys = parseResult.visitorKeys || evk.KEYS;
+
+        debug("Scope analysis:", filePath);
+        const scopeManager = parseResult.scopeManager || analyzeScope(ast, languageOptions, visitorKeys);
+
+        debug("Scope analysis successful:", filePath);
+
+        return {
+            success: true,
+
+            /*
+             * Save all values that `parseForESLint()` returned.
+             * If a `SourceCode` object is given as the first parameter instead of source code text,
+             * linter skips the parsing process and reuses the source code object.
+             * In that case, linter needs all the values that `parseForESLint()` returned.
+             */
+            sourceCode: new SourceCode({
+                text,
+                ast,
+                parserServices,
+                scopeManager,
+                visitorKeys
+            })
+        };
+    } catch (ex) {
+
+        // If the message includes a leading line number, strip it:
+        const message = `Parsing error: ${ex.message.replace(/^line \d+:/iu, "").trim()}`;
+
+        debug("%s\n%s", message, ex.stack);
+
+        return {
+            success: false,
+            error: {
+                ruleId: null,
+                fatal: true,
+                severity: 2,
+                message,
+                line: ex.lineNumber,
+                column: ex.column,
+                nodeType: null
+            }
+        };
+    }
+}
+
+/**
+ * Runs a rule, and gets its listeners
+ * @param {Rule} rule A normalized rule with a `create` method
+ * @param {Context} ruleContext The context that should be passed to the rule
+ * @throws {any} Any error during the rule's `create`
+ * @returns {Object} A map of selector listeners provided by the rule
+ */
+function createRuleListeners(rule, ruleContext) {
+    try {
+        return rule.create(ruleContext);
+    } catch (ex) {
+        ex.message = `Error while loading rule '${ruleContext.id}': ${ex.message}`;
+        throw ex;
+    }
+}
+
+// methods that exist on SourceCode object
+const DEPRECATED_SOURCECODE_PASSTHROUGHS = {
+    getSource: "getText",
+    getSourceLines: "getLines",
+    getAllComments: "getAllComments",
+    getNodeByRangeIndex: "getNodeByRangeIndex",
+    getComments: "getComments",
+    getCommentsBefore: "getCommentsBefore",
+    getCommentsAfter: "getCommentsAfter",
+    getCommentsInside: "getCommentsInside",
+    getJSDocComment: "getJSDocComment",
+    getFirstToken: "getFirstToken",
+    getFirstTokens: "getFirstTokens",
+    getLastToken: "getLastToken",
+    getLastTokens: "getLastTokens",
+    getTokenAfter: "getTokenAfter",
+    getTokenBefore: "getTokenBefore",
+    getTokenByRangeStart: "getTokenByRangeStart",
+    getTokens: "getTokens",
+    getTokensAfter: "getTokensAfter",
+    getTokensBefore: "getTokensBefore",
+    getTokensBetween: "getTokensBetween"
+};
+
+
+const BASE_TRAVERSAL_CONTEXT = Object.freeze(
+    Object.keys(DEPRECATED_SOURCECODE_PASSTHROUGHS).reduce(
+        (contextInfo, methodName) =>
+            Object.assign(contextInfo, {
+                [methodName](...args) {
+                    return this.sourceCode[DEPRECATED_SOURCECODE_PASSTHROUGHS[methodName]](...args);
+                }
+            }),
+        {}
+    )
+);
+
+/**
+ * Runs the given rules on the given SourceCode object
+ * @param {SourceCode} sourceCode A SourceCode object for the given text
+ * @param {Object} configuredRules The rules configuration
+ * @param {function(string): Rule} ruleMapper A mapper function from rule names to rules
+ * @param {string | undefined} parserName The name of the parser in the config
+ * @param {LanguageOptions} languageOptions The options for parsing the code.
+ * @param {Object} settings The settings that were enabled in the config
+ * @param {string} filename The reported filename of the code
+ * @param {boolean} disableFixes If true, it doesn't make `fix` properties.
+ * @param {string | undefined} cwd cwd of the cli
+ * @param {string} physicalFilename The full path of the file on disk without any code block information
+ * @returns {LintMessage[]} An array of reported problems
+ */
+function runRules(sourceCode, configuredRules, ruleMapper, parserName, languageOptions, settings, filename, disableFixes, cwd, physicalFilename) {
+    const emitter = createEmitter();
+    const nodeQueue = [];
+    let currentNode = sourceCode.ast;
+
+    Traverser.traverse(sourceCode.ast, {
+        enter(node, parent) {
+            node.parent = parent;
+            nodeQueue.push({ isEntering: true, node });
+        },
+        leave(node) {
+            nodeQueue.push({ isEntering: false, node });
+        },
+        visitorKeys: sourceCode.visitorKeys
+    });
+
+    /*
+     * Create a frozen object with the ruleContext properties and methods that are shared by all rules.
+     * All rule contexts will inherit from this object. This avoids the performance penalty of copying all the
+     * properties once for each rule.
+     */
+    const sharedTraversalContext = Object.freeze(
+        Object.assign(
+            Object.create(BASE_TRAVERSAL_CONTEXT),
+            {
+                getAncestors: () => sourceCode.getAncestors(currentNode),
+                getDeclaredVariables: node => sourceCode.getDeclaredVariables(node),
+                getCwd: () => cwd,
+                cwd,
+                getFilename: () => filename,
+                filename,
+                getPhysicalFilename: () => physicalFilename || filename,
+                physicalFilename: physicalFilename || filename,
+                getScope: () => sourceCode.getScope(currentNode),
+                getSourceCode: () => sourceCode,
+                sourceCode,
+                markVariableAsUsed: name => sourceCode.markVariableAsUsed(name, currentNode),
+                parserOptions: {
+                    ...languageOptions.parserOptions
+                },
+                parserPath: parserName,
+                languageOptions,
+                parserServices: sourceCode.parserServices,
+                settings
+            }
+        )
+    );
+
+    const lintingProblems = [];
+
+    Object.keys(configuredRules).forEach(ruleId => {
+        const severity = ConfigOps.getRuleSeverity(configuredRules[ruleId]);
+
+        // not load disabled rules
+        if (severity === 0) {
+            return;
+        }
+
+        const rule = ruleMapper(ruleId);
+
+        if (!rule) {
+            lintingProblems.push(createLintingProblem({ ruleId }));
+            return;
+        }
+
+        const messageIds = rule.meta && rule.meta.messages;
+        let reportTranslator = null;
+        const ruleContext = Object.freeze(
+            Object.assign(
+                Object.create(sharedTraversalContext),
+                {
+                    id: ruleId,
+                    options: getRuleOptions(configuredRules[ruleId]),
+                    report(...args) {
+
+                        /*
+                         * Create a report translator lazily.
+                         * In a vast majority of cases, any given rule reports zero errors on a given
+                         * piece of code. Creating a translator lazily avoids the performance cost of
+                         * creating a new translator function for each rule that usually doesn't get
+                         * called.
+                         *
+                         * Using lazy report translators improves end-to-end performance by about 3%
+                         * with Node 8.4.0.
+                         */
+                        if (reportTranslator === null) {
+                            reportTranslator = createReportTranslator({
+                                ruleId,
+                                severity,
+                                sourceCode,
+                                messageIds,
+                                disableFixes
+                            });
+                        }
+                        const problem = reportTranslator(...args);
+
+                        if (problem.fix && !(rule.meta && rule.meta.fixable)) {
+                            throw new Error("Fixable rules must set the `meta.fixable` property to \"code\" or \"whitespace\".");
+                        }
+                        if (problem.suggestions && !(rule.meta && rule.meta.hasSuggestions === true)) {
+                            if (rule.meta && rule.meta.docs && typeof rule.meta.docs.suggestion !== "undefined") {
+
+                                // Encourage migration from the former property name.
+                                throw new Error("Rules with suggestions must set the `meta.hasSuggestions` property to `true`. `meta.docs.suggestion` is ignored by ESLint.");
+                            }
+                            throw new Error("Rules with suggestions must set the `meta.hasSuggestions` property to `true`.");
+                        }
+                        lintingProblems.push(problem);
+                    }
+                }
+            )
+        );
+
+        const ruleListeners = timing.enabled ? timing.time(ruleId, createRuleListeners)(rule, ruleContext) : createRuleListeners(rule, ruleContext);
+
+        /**
+         * Include `ruleId` in error logs
+         * @param {Function} ruleListener A rule method that listens for a node.
+         * @returns {Function} ruleListener wrapped in error handler
+         */
+        function addRuleErrorHandler(ruleListener) {
+            return function ruleErrorHandler(...listenerArgs) {
+                try {
+                    return ruleListener(...listenerArgs);
+                } catch (e) {
+                    e.ruleId = ruleId;
+                    throw e;
+                }
+            };
+        }
+
+        if (typeof ruleListeners === "undefined" || ruleListeners === null) {
+            throw new Error(`The create() function for rule '${ruleId}' did not return an object.`);
+        }
+
+        // add all the selectors from the rule as listeners
+        Object.keys(ruleListeners).forEach(selector => {
+            const ruleListener = timing.enabled
+                ? timing.time(ruleId, ruleListeners[selector])
+                : ruleListeners[selector];
+
+            emitter.on(
+                selector,
+                addRuleErrorHandler(ruleListener)
+            );
+        });
+    });
+
+    // only run code path analyzer if the top level node is "Program", skip otherwise
+    const eventGenerator = nodeQueue[0].node.type === "Program"
+        ? new CodePathAnalyzer(new NodeEventGenerator(emitter, { visitorKeys: sourceCode.visitorKeys, fallback: Traverser.getKeys }))
+        : new NodeEventGenerator(emitter, { visitorKeys: sourceCode.visitorKeys, fallback: Traverser.getKeys });
+
+    nodeQueue.forEach(traversalInfo => {
+        currentNode = traversalInfo.node;
+
+        try {
+            if (traversalInfo.isEntering) {
+                eventGenerator.enterNode(currentNode);
+            } else {
+                eventGenerator.leaveNode(currentNode);
+            }
+        } catch (err) {
+            err.currentNode = currentNode;
+            throw err;
+        }
+    });
+
+    return lintingProblems;
+}
+
+/**
+ * Ensure the source code to be a string.
+ * @param {string|SourceCode} textOrSourceCode The text or source code object.
+ * @returns {string} The source code text.
+ */
+function ensureText(textOrSourceCode) {
+    if (typeof textOrSourceCode === "object") {
+        const { hasBOM, text } = textOrSourceCode;
+        const bom = hasBOM ? "\uFEFF" : "";
+
+        return bom + text;
+    }
+
+    return String(textOrSourceCode);
+}
+
+/**
+ * Get an environment.
+ * @param {LinterInternalSlots} slots The internal slots of Linter.
+ * @param {string} envId The environment ID to get.
+ * @returns {Environment|null} The environment.
+ */
+function getEnv(slots, envId) {
+    return (
+        (slots.lastConfigArray && slots.lastConfigArray.pluginEnvironments.get(envId)) ||
+        BuiltInEnvironments.get(envId) ||
+        null
+    );
+}
+
+/**
+ * Get a rule.
+ * @param {LinterInternalSlots} slots The internal slots of Linter.
+ * @param {string} ruleId The rule ID to get.
+ * @returns {Rule|null} The rule.
+ */
+function getRule(slots, ruleId) {
+    return (
+        (slots.lastConfigArray && slots.lastConfigArray.pluginRules.get(ruleId)) ||
+        slots.ruleMap.get(ruleId)
+    );
+}
+
+/**
+ * Normalize the value of the cwd
+ * @param {string | undefined} cwd raw value of the cwd, path to a directory that should be considered as the current working directory, can be undefined.
+ * @returns {string | undefined} normalized cwd
+ */
+function normalizeCwd(cwd) {
+    if (cwd) {
+        return cwd;
+    }
+    if (typeof process === "object") {
+        return process.cwd();
+    }
+
+    // It's more explicit to assign the undefined
+    // eslint-disable-next-line no-undefined -- Consistently returning a value
+    return undefined;
+}
+
+/**
+ * The map to store private data.
+ * @type {WeakMap<Linter, LinterInternalSlots>}
+ */
+const internalSlotsMap = new WeakMap();
+
+/**
+ * Throws an error when the given linter is in flat config mode.
+ * @param {Linter} linter The linter to check.
+ * @returns {void}
+ * @throws {Error} If the linter is in flat config mode.
+ */
+function assertEslintrcConfig(linter) {
+    const { configType } = internalSlotsMap.get(linter);
+
+    if (configType === "flat") {
+        throw new Error("This method cannot be used with flat config. Add your entries directly into the config array.");
+    }
+}
+
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+/**
+ * Object that is responsible for verifying JavaScript text
+ * @name Linter
+ */
+class Linter {
+
+    /**
+     * Initialize the Linter.
+     * @param {Object} [config] the config object
+     * @param {string} [config.cwd] path to a directory that should be considered as the current working directory, can be undefined.
+     * @param {"flat"|"eslintrc"} [config.configType="eslintrc"] the type of config used.
+     */
+    constructor({ cwd, configType } = {}) {
+        internalSlotsMap.set(this, {
+            cwd: normalizeCwd(cwd),
+            lastConfigArray: null,
+            lastSourceCode: null,
+            lastSuppressedMessages: [],
+            configType, // TODO: Remove after flat config conversion
+            parserMap: new Map([["espree", espree]]),
+            ruleMap: new Rules()
+        });
+
+        this.version = pkg.version;
+    }
+
+    /**
+     * Getter for package version.
+     * @static
+     * @returns {string} The version from package.json.
+     */
+    static get version() {
+        return pkg.version;
+    }
+
+    /**
+     * Same as linter.verify, except without support for processors.
+     * @param {string|SourceCode} textOrSourceCode The text to parse or a SourceCode object.
+     * @param {ConfigData} providedConfig An ESLintConfig instance to configure everything.
+     * @param {VerifyOptions} [providedOptions] The optional filename of the file being checked.
+     * @throws {Error} If during rule execution.
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The results as an array of messages or an empty array if no messages.
+     */
+    _verifyWithoutProcessors(textOrSourceCode, providedConfig, providedOptions) {
+        const slots = internalSlotsMap.get(this);
+        const config = providedConfig || {};
+        const options = normalizeVerifyOptions(providedOptions, config);
+        let text;
+
+        // evaluate arguments
+        if (typeof textOrSourceCode === "string") {
+            slots.lastSourceCode = null;
+            text = textOrSourceCode;
+        } else {
+            slots.lastSourceCode = textOrSourceCode;
+            text = textOrSourceCode.text;
+        }
+
+        // Resolve parser.
+        let parserName = DEFAULT_PARSER_NAME;
+        let parser = espree;
+
+        if (typeof config.parser === "object" && config.parser !== null) {
+            parserName = config.parser.filePath;
+            parser = config.parser.definition;
+        } else if (typeof config.parser === "string") {
+            if (!slots.parserMap.has(config.parser)) {
+                return [{
+                    ruleId: null,
+                    fatal: true,
+                    severity: 2,
+                    message: `Configured parser '${config.parser}' was not found.`,
+                    line: 0,
+                    column: 0,
+                    nodeType: null
+                }];
+            }
+            parserName = config.parser;
+            parser = slots.parserMap.get(config.parser);
+        }
+
+        // search and apply "eslint-env *".
+        const envInFile = options.allowInlineConfig && !options.warnInlineConfig
+            ? findEslintEnv(text)
+            : {};
+        const resolvedEnvConfig = Object.assign({ builtin: true }, config.env, envInFile);
+        const enabledEnvs = Object.keys(resolvedEnvConfig)
+            .filter(envName => resolvedEnvConfig[envName])
+            .map(envName => getEnv(slots, envName))
+            .filter(env => env);
+
+        const parserOptions = resolveParserOptions(parser, config.parserOptions || {}, enabledEnvs);
+        const configuredGlobals = resolveGlobals(config.globals || {}, enabledEnvs);
+        const settings = config.settings || {};
+        const languageOptions = createLanguageOptions({
+            globals: config.globals,
+            parser,
+            parserOptions
+        });
+
+        if (!slots.lastSourceCode) {
+            const parseResult = parse(
+                text,
+                languageOptions,
+                options.filename
+            );
+
+            if (!parseResult.success) {
+                return [parseResult.error];
+            }
+
+            slots.lastSourceCode = parseResult.sourceCode;
+        } else {
+
+            /*
+             * If the given source code object as the first argument does not have scopeManager, analyze the scope.
+             * This is for backward compatibility (SourceCode is frozen so it cannot rebind).
+             */
+            if (!slots.lastSourceCode.scopeManager) {
+                slots.lastSourceCode = new SourceCode({
+                    text: slots.lastSourceCode.text,
+                    ast: slots.lastSourceCode.ast,
+                    parserServices: slots.lastSourceCode.parserServices,
+                    visitorKeys: slots.lastSourceCode.visitorKeys,
+                    scopeManager: analyzeScope(slots.lastSourceCode.ast, languageOptions)
+                });
+            }
+        }
+
+        const sourceCode = slots.lastSourceCode;
+        const commentDirectives = options.allowInlineConfig
+            ? getDirectiveComments(sourceCode, ruleId => getRule(slots, ruleId), options.warnInlineConfig)
+            : { configuredRules: {}, enabledGlobals: {}, exportedVariables: {}, problems: [], disableDirectives: [] };
+
+        // augment global scope with declared global variables
+        addDeclaredGlobals(
+            sourceCode.scopeManager.scopes[0],
+            configuredGlobals,
+            { exportedVariables: commentDirectives.exportedVariables, enabledGlobals: commentDirectives.enabledGlobals }
+        );
+
+        const configuredRules = Object.assign({}, config.rules, commentDirectives.configuredRules);
+        let lintingProblems;
+
+        try {
+            lintingProblems = runRules(
+                sourceCode,
+                configuredRules,
+                ruleId => getRule(slots, ruleId),
+                parserName,
+                languageOptions,
+                settings,
+                options.filename,
+                options.disableFixes,
+                slots.cwd,
+                providedOptions.physicalFilename
+            );
+        } catch (err) {
+            err.message += `\nOccurred while linting ${options.filename}`;
+            debug("An error occurred while traversing");
+            debug("Filename:", options.filename);
+            if (err.currentNode) {
+                const { line } = err.currentNode.loc.start;
+
+                debug("Line:", line);
+                err.message += `:${line}`;
+            }
+            debug("Parser Options:", parserOptions);
+            debug("Parser Path:", parserName);
+            debug("Settings:", settings);
+
+            if (err.ruleId) {
+                err.message += `\nRule: "${err.ruleId}"`;
+            }
+
+            throw err;
+        }
+
+        return applyDisableDirectives({
+            directives: commentDirectives.disableDirectives,
+            disableFixes: options.disableFixes,
+            problems: lintingProblems
+                .concat(commentDirectives.problems)
+                .sort((problemA, problemB) => problemA.line - problemB.line || problemA.column - problemB.column),
+            reportUnusedDisableDirectives: options.reportUnusedDisableDirectives
+        });
+    }
+
+    /**
+     * Verifies the text against the rules specified by the second argument.
+     * @param {string|SourceCode} textOrSourceCode The text to parse or a SourceCode object.
+     * @param {ConfigData|ConfigArray} config An ESLintConfig instance to configure everything.
+     * @param {(string|(VerifyOptions&ProcessorOptions))} [filenameOrOptions] The optional filename of the file being checked.
+     *      If this is not set, the filename will default to '<input>' in the rule context. If
+     *      an object, then it has "filename", "allowInlineConfig", and some properties.
+     * @returns {LintMessage[]} The results as an array of messages or an empty array if no messages.
+     */
+    verify(textOrSourceCode, config, filenameOrOptions) {
+        debug("Verify");
+
+        const { configType, cwd } = internalSlotsMap.get(this);
+
+        const options = typeof filenameOrOptions === "string"
+            ? { filename: filenameOrOptions }
+            : filenameOrOptions || {};
+
+        if (config) {
+            if (configType === "flat") {
+
+                /*
+                 * Because of how Webpack packages up the files, we can't
+                 * compare directly to `FlatConfigArray` using `instanceof`
+                 * because it's not the same `FlatConfigArray` as in the tests.
+                 * So, we work around it by assuming an array is, in fact, a
+                 * `FlatConfigArray` if it has a `getConfig()` method.
+                 */
+                let configArray = config;
+
+                if (!Array.isArray(config) || typeof config.getConfig !== "function") {
+                    configArray = new FlatConfigArray(config, { basePath: cwd });
+                    configArray.normalizeSync();
+                }
+
+                return this._distinguishSuppressedMessages(this._verifyWithFlatConfigArray(textOrSourceCode, configArray, options, true));
+            }
+
+            if (typeof config.extractConfig === "function") {
+                return this._distinguishSuppressedMessages(this._verifyWithConfigArray(textOrSourceCode, config, options));
+            }
+        }
+
+        /*
+         * If we get to here, it means `config` is just an object rather
+         * than a config array so we can go right into linting.
+         */
+
+        /*
+         * `Linter` doesn't support `overrides` property in configuration.
+         * So we cannot apply multiple processors.
+         */
+        if (options.preprocess || options.postprocess) {
+            return this._distinguishSuppressedMessages(this._verifyWithProcessor(textOrSourceCode, config, options));
+        }
+        return this._distinguishSuppressedMessages(this._verifyWithoutProcessors(textOrSourceCode, config, options));
+    }
+
+    /**
+     * Verify with a processor.
+     * @param {string|SourceCode} textOrSourceCode The source code.
+     * @param {FlatConfig} config The config array.
+     * @param {VerifyOptions&ProcessorOptions} options The options.
+     * @param {FlatConfigArray} [configForRecursive] The `ConfigArray` object to apply multiple processors recursively.
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The found problems.
+     */
+    _verifyWithFlatConfigArrayAndProcessor(textOrSourceCode, config, options, configForRecursive) {
+        const filename = options.filename || "<input>";
+        const filenameToExpose = normalizeFilename(filename);
+        const physicalFilename = options.physicalFilename || filenameToExpose;
+        const text = ensureText(textOrSourceCode);
+        const preprocess = options.preprocess || (rawText => [rawText]);
+        const postprocess = options.postprocess || (messagesList => messagesList.flat());
+        const filterCodeBlock =
+            options.filterCodeBlock ||
+            (blockFilename => blockFilename.endsWith(".js"));
+        const originalExtname = path.extname(filename);
+
+        let blocks;
+
+        try {
+            blocks = preprocess(text, filenameToExpose);
+        } catch (ex) {
+
+            // If the message includes a leading line number, strip it:
+            const message = `Preprocessing error: ${ex.message.replace(/^line \d+:/iu, "").trim()}`;
+
+            debug("%s\n%s", message, ex.stack);
+
+            return [
+                {
+                    ruleId: null,
+                    fatal: true,
+                    severity: 2,
+                    message,
+                    line: ex.lineNumber,
+                    column: ex.column,
+                    nodeType: null
+                }
+            ];
+        }
+
+        const messageLists = blocks.map((block, i) => {
+            debug("A code block was found: %o", block.filename || "(unnamed)");
+
+            // Keep the legacy behavior.
+            if (typeof block === "string") {
+                return this._verifyWithFlatConfigArrayAndWithoutProcessors(block, config, options);
+            }
+
+            const blockText = block.text;
+            const blockName = path.join(filename, `${i}_${block.filename}`);
+
+            // Skip this block if filtered.
+            if (!filterCodeBlock(blockName, blockText)) {
+                debug("This code block was skipped.");
+                return [];
+            }
+
+            // Resolve configuration again if the file content or extension was changed.
+            if (configForRecursive && (text !== blockText || path.extname(blockName) !== originalExtname)) {
+                debug("Resolving configuration again because the file content or extension was changed.");
+                return this._verifyWithFlatConfigArray(
+                    blockText,
+                    configForRecursive,
+                    { ...options, filename: blockName, physicalFilename }
+                );
+            }
+
+            // Does lint.
+            return this._verifyWithFlatConfigArrayAndWithoutProcessors(
+                blockText,
+                config,
+                { ...options, filename: blockName, physicalFilename }
+            );
+        });
+
+        return postprocess(messageLists, filenameToExpose);
+    }
+
+    /**
+     * Same as linter.verify, except without support for processors.
+     * @param {string|SourceCode} textOrSourceCode The text to parse or a SourceCode object.
+     * @param {FlatConfig} providedConfig An ESLintConfig instance to configure everything.
+     * @param {VerifyOptions} [providedOptions] The optional filename of the file being checked.
+     * @throws {Error} If during rule execution.
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The results as an array of messages or an empty array if no messages.
+     */
+    _verifyWithFlatConfigArrayAndWithoutProcessors(textOrSourceCode, providedConfig, providedOptions) {
+        const slots = internalSlotsMap.get(this);
+        const config = providedConfig || {};
+        const options = normalizeVerifyOptions(providedOptions, config);
+        let text;
+
+        // evaluate arguments
+        if (typeof textOrSourceCode === "string") {
+            slots.lastSourceCode = null;
+            text = textOrSourceCode;
+        } else {
+            slots.lastSourceCode = textOrSourceCode;
+            text = textOrSourceCode.text;
+        }
+
+        const languageOptions = config.languageOptions;
+
+        languageOptions.ecmaVersion = normalizeEcmaVersionForLanguageOptions(
+            languageOptions.ecmaVersion
+        );
+
+        // double check that there is a parser to avoid mysterious error messages
+        if (!languageOptions.parser) {
+            throw new TypeError(`No parser specified for ${options.filename}`);
+        }
+
+        // Espree expects this information to be passed in
+        if (isEspree(languageOptions.parser)) {
+            const parserOptions = languageOptions.parserOptions;
+
+            if (languageOptions.sourceType) {
+
+                parserOptions.sourceType = languageOptions.sourceType;
+
+                if (
+                    parserOptions.sourceType === "module" &&
+                    parserOptions.ecmaFeatures &&
+                    parserOptions.ecmaFeatures.globalReturn
+                ) {
+                    parserOptions.ecmaFeatures.globalReturn = false;
+                }
+            }
+        }
+
+        const settings = config.settings || {};
+
+        if (!slots.lastSourceCode) {
+            const parseResult = parse(
+                text,
+                languageOptions,
+                options.filename
+            );
+
+            if (!parseResult.success) {
+                return [parseResult.error];
+            }
+
+            slots.lastSourceCode = parseResult.sourceCode;
+        } else {
+
+            /*
+             * If the given source code object as the first argument does not have scopeManager, analyze the scope.
+             * This is for backward compatibility (SourceCode is frozen so it cannot rebind).
+             */
+            if (!slots.lastSourceCode.scopeManager) {
+                slots.lastSourceCode = new SourceCode({
+                    text: slots.lastSourceCode.text,
+                    ast: slots.lastSourceCode.ast,
+                    parserServices: slots.lastSourceCode.parserServices,
+                    visitorKeys: slots.lastSourceCode.visitorKeys,
+                    scopeManager: analyzeScope(slots.lastSourceCode.ast, languageOptions)
+                });
+            }
+        }
+
+        const sourceCode = slots.lastSourceCode;
+
+        /*
+         * Make adjustments based on the language options. For JavaScript,
+         * this is primarily about adding variables into the global scope
+         * to account for ecmaVersion and configured globals.
+         */
+        sourceCode.applyLanguageOptions(languageOptions);
+
+        const mergedInlineConfig = {
+            rules: {}
+        };
+        const inlineConfigProblems = [];
+
+        /*
+         * Inline config can be either enabled or disabled. If disabled, it's possible
+         * to detect the inline config and emit a warning (though this is not required).
+         * So we first check to see if inline config is allowed at all, and if so, we
+         * need to check if it's a warning or not.
+         */
+        if (options.allowInlineConfig) {
+
+            // if inline config should warn then add the warnings
+            if (options.warnInlineConfig) {
+                sourceCode.getInlineConfigNodes().forEach(node => {
+                    inlineConfigProblems.push(createLintingProblem({
+                        ruleId: null,
+                        message: `'${sourceCode.text.slice(node.range[0], node.range[1])}' has no effect because you have 'noInlineConfig' setting in ${options.warnInlineConfig}.`,
+                        loc: node.loc,
+                        severity: 1
+                    }));
+
+                });
+            } else {
+                const inlineConfigResult = sourceCode.applyInlineConfig();
+
+                inlineConfigProblems.push(
+                    ...inlineConfigResult.problems
+                        .map(createLintingProblem)
+                        .map(problem => {
+                            problem.fatal = true;
+                            return problem;
+                        })
+                );
+
+                // next we need to verify information about the specified rules
+                const ruleValidator = new RuleValidator();
+
+                for (const { config: inlineConfig, node } of inlineConfigResult.configs) {
+
+                    Object.keys(inlineConfig.rules).forEach(ruleId => {
+                        const rule = getRuleFromConfig(ruleId, config);
+                        const ruleValue = inlineConfig.rules[ruleId];
+
+                        if (!rule) {
+                            inlineConfigProblems.push(createLintingProblem({ ruleId, loc: node.loc }));
+                            return;
+                        }
+
+                        try {
+
+                            const ruleOptions = Array.isArray(ruleValue) ? ruleValue : [ruleValue];
+
+                            assertIsRuleOptions(ruleId, ruleValue);
+                            assertIsRuleSeverity(ruleId, ruleOptions[0]);
+
+                            ruleValidator.validate({
+                                plugins: config.plugins,
+                                rules: {
+                                    [ruleId]: ruleOptions
+                                }
+                            });
+                            mergedInlineConfig.rules[ruleId] = ruleValue;
+                        } catch (err) {
+
+                            let baseMessage = err.message.slice(
+                                err.message.startsWith("Key \"rules\":")
+                                    ? err.message.indexOf(":", 12) + 1
+                                    : err.message.indexOf(":") + 1
+                            ).trim();
+
+                            if (err.messageTemplate) {
+                                baseMessage += ` You passed "${ruleValue}".`;
+                            }
+
+                            inlineConfigProblems.push(createLintingProblem({
+                                ruleId,
+                                message: `Inline configuration for rule "${ruleId}" is invalid:\n\t${baseMessage}\n`,
+                                loc: node.loc
+                            }));
+                        }
+                    });
+                }
+            }
+        }
+
+        const commentDirectives = options.allowInlineConfig && !options.warnInlineConfig
+            ? getDirectiveCommentsForFlatConfig(
+                sourceCode,
+                ruleId => getRuleFromConfig(ruleId, config)
+            )
+            : { problems: [], disableDirectives: [] };
+
+        const configuredRules = Object.assign({}, config.rules, mergedInlineConfig.rules);
+        let lintingProblems;
+
+        sourceCode.finalize();
+
+        try {
+            lintingProblems = runRules(
+                sourceCode,
+                configuredRules,
+                ruleId => getRuleFromConfig(ruleId, config),
+                void 0,
+                languageOptions,
+                settings,
+                options.filename,
+                options.disableFixes,
+                slots.cwd,
+                providedOptions.physicalFilename
+            );
+        } catch (err) {
+            err.message += `\nOccurred while linting ${options.filename}`;
+            debug("An error occurred while traversing");
+            debug("Filename:", options.filename);
+            if (err.currentNode) {
+                const { line } = err.currentNode.loc.start;
+
+                debug("Line:", line);
+                err.message += `:${line}`;
+            }
+            debug("Parser Options:", languageOptions.parserOptions);
+
+            // debug("Parser Path:", parserName);
+            debug("Settings:", settings);
+
+            if (err.ruleId) {
+                err.message += `\nRule: "${err.ruleId}"`;
+            }
+
+            throw err;
+        }
+
+        return applyDisableDirectives({
+            directives: commentDirectives.disableDirectives,
+            disableFixes: options.disableFixes,
+            problems: lintingProblems
+                .concat(commentDirectives.problems)
+                .concat(inlineConfigProblems)
+                .sort((problemA, problemB) => problemA.line - problemB.line || problemA.column - problemB.column),
+            reportUnusedDisableDirectives: options.reportUnusedDisableDirectives
+        });
+    }
+
+    /**
+     * Verify a given code with `ConfigArray`.
+     * @param {string|SourceCode} textOrSourceCode The source code.
+     * @param {ConfigArray} configArray The config array.
+     * @param {VerifyOptions&ProcessorOptions} options The options.
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The found problems.
+     */
+    _verifyWithConfigArray(textOrSourceCode, configArray, options) {
+        debug("With ConfigArray: %s", options.filename);
+
+        // Store the config array in order to get plugin envs and rules later.
+        internalSlotsMap.get(this).lastConfigArray = configArray;
+
+        // Extract the final config for this file.
+        const config = configArray.extractConfig(options.filename);
+        const processor =
+            config.processor &&
+            configArray.pluginProcessors.get(config.processor);
+
+        // Verify.
+        if (processor) {
+            debug("Apply the processor: %o", config.processor);
+            const { preprocess, postprocess, supportsAutofix } = processor;
+            const disableFixes = options.disableFixes || !supportsAutofix;
+
+            return this._verifyWithProcessor(
+                textOrSourceCode,
+                config,
+                { ...options, disableFixes, postprocess, preprocess },
+                configArray
+            );
+        }
+        return this._verifyWithoutProcessors(textOrSourceCode, config, options);
+    }
+
+    /**
+     * Verify a given code with a flat config.
+     * @param {string|SourceCode} textOrSourceCode The source code.
+     * @param {FlatConfigArray} configArray The config array.
+     * @param {VerifyOptions&ProcessorOptions} options The options.
+     * @param {boolean} [firstCall=false] Indicates if this is being called directly
+     *      from verify(). (TODO: Remove once eslintrc is removed.)
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The found problems.
+     */
+    _verifyWithFlatConfigArray(textOrSourceCode, configArray, options, firstCall = false) {
+        debug("With flat config: %s", options.filename);
+
+        // we need a filename to match configs against
+        const filename = options.filename || "__placeholder__.js";
+
+        // Store the config array in order to get plugin envs and rules later.
+        internalSlotsMap.get(this).lastConfigArray = configArray;
+        const config = configArray.getConfig(filename);
+
+        if (!config) {
+            return [
+                {
+                    ruleId: null,
+                    severity: 1,
+                    message: `No matching configuration found for ${filename}.`,
+                    line: 0,
+                    column: 0,
+                    nodeType: null
+                }
+            ];
+        }
+
+        // Verify.
+        if (config.processor) {
+            debug("Apply the processor: %o", config.processor);
+            const { preprocess, postprocess, supportsAutofix } = config.processor;
+            const disableFixes = options.disableFixes || !supportsAutofix;
+
+            return this._verifyWithFlatConfigArrayAndProcessor(
+                textOrSourceCode,
+                config,
+                { ...options, filename, disableFixes, postprocess, preprocess },
+                configArray
+            );
+        }
+
+        // check for options-based processing
+        if (firstCall && (options.preprocess || options.postprocess)) {
+            return this._verifyWithFlatConfigArrayAndProcessor(textOrSourceCode, config, options);
+        }
+
+        return this._verifyWithFlatConfigArrayAndWithoutProcessors(textOrSourceCode, config, options);
+    }
+
+    /**
+     * Verify with a processor.
+     * @param {string|SourceCode} textOrSourceCode The source code.
+     * @param {ConfigData|ExtractedConfig} config The config array.
+     * @param {VerifyOptions&ProcessorOptions} options The options.
+     * @param {ConfigArray} [configForRecursive] The `ConfigArray` object to apply multiple processors recursively.
+     * @returns {(LintMessage|SuppressedLintMessage)[]} The found problems.
+     */
+    _verifyWithProcessor(textOrSourceCode, config, options, configForRecursive) {
+        const filename = options.filename || "<input>";
+        const filenameToExpose = normalizeFilename(filename);
+        const physicalFilename = options.physicalFilename || filenameToExpose;
+        const text = ensureText(textOrSourceCode);
+        const preprocess = options.preprocess || (rawText => [rawText]);
+        const postprocess = options.postprocess || (messagesList => messagesList.flat());
+        const filterCodeBlock =
+            options.filterCodeBlock ||
+            (blockFilename => blockFilename.endsWith(".js"));
+        const originalExtname = path.extname(filename);
+
+        let blocks;
+
+        try {
+            blocks = preprocess(text, filenameToExpose);
+        } catch (ex) {
+
+            // If the message includes a leading line number, strip it:
+            const message = `Preprocessing error: ${ex.message.replace(/^line \d+:/iu, "").trim()}`;
+
+            debug("%s\n%s", message, ex.stack);
+
+            return [
+                {
+                    ruleId: null,
+                    fatal: true,
+                    severity: 2,
+                    message,
+                    line: ex.lineNumber,
+                    column: ex.column,
+                    nodeType: null
+                }
+            ];
+        }
+
+        const messageLists = blocks.map((block, i) => {
+            debug("A code block was found: %o", block.filename || "(unnamed)");
+
+            // Keep the legacy behavior.
+            if (typeof block === "string") {
+                return this._verifyWithoutProcessors(block, config, options);
+            }
+
+            const blockText = block.text;
+            const blockName = path.join(filename, `${i}_${block.filename}`);
+
+            // Skip this block if filtered.
+            if (!filterCodeBlock(blockName, blockText)) {
+                debug("This code block was skipped.");
+                return [];
+            }
+
+            // Resolve configuration again if the file content or extension was changed.
+            if (configForRecursive && (text !== blockText || path.extname(blockName) !== originalExtname)) {
+                debug("Resolving configuration again because the file content or extension was changed.");
+                return this._verifyWithConfigArray(
+                    blockText,
+                    configForRecursive,
+                    { ...options, filename: blockName, physicalFilename }
+                );
+            }
+
+            // Does lint.
+            return this._verifyWithoutProcessors(
+                blockText,
+                config,
+                { ...options, filename: blockName, physicalFilename }
+            );
+        });
+
+        return postprocess(messageLists, filenameToExpose);
+    }
+
+    /**
+     * Given a list of reported problems, distinguish problems between normal messages and suppressed messages.
+     * The normal messages will be returned and the suppressed messages will be stored as lastSuppressedMessages.
+     * @param {Array<LintMessage|SuppressedLintMessage>} problems A list of reported problems.
+     * @returns {LintMessage[]} A list of LintMessage.
+     */
+    _distinguishSuppressedMessages(problems) {
+        const messages = [];
+        const suppressedMessages = [];
+        const slots = internalSlotsMap.get(this);
+
+        for (const problem of problems) {
+            if (problem.suppressions) {
+                suppressedMessages.push(problem);
+            } else {
+                messages.push(problem);
+            }
+        }
+
+        slots.lastSuppressedMessages = suppressedMessages;
+
+        return messages;
+    }
+
+    /**
+     * Gets the SourceCode object representing the parsed source.
+     * @returns {SourceCode} The SourceCode object.
+     */
+    getSourceCode() {
+        return internalSlotsMap.get(this).lastSourceCode;
+    }
+
+    /**
+     * Gets the list of SuppressedLintMessage produced in the last running.
+     * @returns {SuppressedLintMessage[]} The list of SuppressedLintMessage
+     */
+    getSuppressedMessages() {
+        return internalSlotsMap.get(this).lastSuppressedMessages;
+    }
+
+    /**
+     * Defines a new linting rule.
+     * @param {string} ruleId A unique rule identifier
+     * @param {Function | Rule} ruleModule Function from context to object mapping AST node types to event handlers
+     * @returns {void}
+     */
+    defineRule(ruleId, ruleModule) {
+        assertEslintrcConfig(this);
+        internalSlotsMap.get(this).ruleMap.define(ruleId, ruleModule);
+    }
+
+    /**
+     * Defines many new linting rules.
+     * @param {Record<string, Function | Rule>} rulesToDefine map from unique rule identifier to rule
+     * @returns {void}
+     */
+    defineRules(rulesToDefine) {
+        assertEslintrcConfig(this);
+        Object.getOwnPropertyNames(rulesToDefine).forEach(ruleId => {
+            this.defineRule(ruleId, rulesToDefine[ruleId]);
+        });
+    }
+
+    /**
+     * Gets an object with all loaded rules.
+     * @returns {Map<string, Rule>} All loaded rules
+     */
+    getRules() {
+        assertEslintrcConfig(this);
+        const { lastConfigArray, ruleMap } = internalSlotsMap.get(this);
+
+        return new Map(function *() {
+            yield* ruleMap;
+
+            if (lastConfigArray) {
+                yield* lastConfigArray.pluginRules;
+            }
+        }());
+    }
+
+    /**
+     * Define a new parser module
+     * @param {string} parserId Name of the parser
+     * @param {Parser} parserModule The parser object
+     * @returns {void}
+     */
+    defineParser(parserId, parserModule) {
+        assertEslintrcConfig(this);
+        internalSlotsMap.get(this).parserMap.set(parserId, parserModule);
+    }
+
+    /**
+     * Performs multiple autofix passes over the text until as many fixes as possible
+     * have been applied.
+     * @param {string} text The source text to apply fixes to.
+     * @param {ConfigData|ConfigArray|FlatConfigArray} config The ESLint config object to use.
+     * @param {VerifyOptions&ProcessorOptions&FixOptions} options The ESLint options object to use.
+     * @returns {{fixed:boolean,messages:LintMessage[],output:string}} The result of the fix operation as returned from the
+     *      SourceCodeFixer.
+     */
+    verifyAndFix(text, config, options) {
+        let messages = [],
+            fixedResult,
+            fixed = false,
+            passNumber = 0,
+            currentText = text;
+        const debugTextDescription = options && options.filename || `${text.slice(0, 10)}...`;
+        const shouldFix = options && typeof options.fix !== "undefined" ? options.fix : true;
+
+        /**
+         * This loop continues until one of the following is true:
+         *
+         * 1. No more fixes have been applied.
+         * 2. Ten passes have been made.
+         *
+         * That means anytime a fix is successfully applied, there will be another pass.
+         * Essentially, guaranteeing a minimum of two passes.
+         */
+        do {
+            passNumber++;
+
+            debug(`Linting code for ${debugTextDescription} (pass ${passNumber})`);
+            messages = this.verify(currentText, config, options);
+
+            debug(`Generating fixed text for ${debugTextDescription} (pass ${passNumber})`);
+            fixedResult = SourceCodeFixer.applyFixes(currentText, messages, shouldFix);
+
+            /*
+             * stop if there are any syntax errors.
+             * 'fixedResult.output' is a empty string.
+             */
+            if (messages.length === 1 && messages[0].fatal) {
+                break;
+            }
+
+            // keep track if any fixes were ever applied - important for return value
+            fixed = fixed || fixedResult.fixed;
+
+            // update to use the fixed output instead of the original text
+            currentText = fixedResult.output;
+
+        } while (
+            fixedResult.fixed &&
+            passNumber < MAX_AUTOFIX_PASSES
+        );
+
+        /*
+         * If the last result had fixes, we need to lint again to be sure we have
+         * the most up-to-date information.
+         */
+        if (fixedResult.fixed) {
+            fixedResult.messages = this.verify(currentText, config, options);
+        }
+
+        // ensure the last result properly reflects if fixes were done
+        fixedResult.fixed = fixed;
+        fixedResult.output = currentText;
+
+        return fixedResult;
+    }
+}
+
+module.exports = {
+    Linter,
+
+    /**
+     * Get the internal slots of a given Linter instance for tests.
+     * @param {Linter} instance The Linter instance to get.
+     * @returns {LinterInternalSlots} The internal slots.
+     */
+    getLinterInternalSlots(instance) {
+        return internalSlotsMap.get(instance);
+    }
+};