242 lines
		
	
	
		
			7.3 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			242 lines
		
	
	
		
			7.3 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @fileoverview Rule to flag updates of imported bindings.
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 * @author Toru Nagashima <https://github.com/mysticatea>
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 */
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"use strict";
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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const { findVariable } = require("@eslint-community/eslint-utils");
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const astUtils = require("./utils/ast-utils");
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const WellKnownMutationFunctions = {
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    Object: /^(?:assign|definePropert(?:y|ies)|freeze|setPrototypeOf)$/u,
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    Reflect: /^(?:(?:define|delete)Property|set(?:PrototypeOf)?)$/u
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};
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/**
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 * Check if a given node is LHS of an assignment node.
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 * @param {ASTNode} node The node to check.
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 * @returns {boolean} `true` if the node is LHS.
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 */
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function isAssignmentLeft(node) {
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    const { parent } = node;
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    return (
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        (
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            parent.type === "AssignmentExpression" &&
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            parent.left === node
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        ) ||
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        // Destructuring assignments
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        parent.type === "ArrayPattern" ||
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        (
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            parent.type === "Property" &&
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            parent.value === node &&
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            parent.parent.type === "ObjectPattern"
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        ) ||
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        parent.type === "RestElement" ||
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        (
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            parent.type === "AssignmentPattern" &&
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            parent.left === node
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        )
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    );
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}
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/**
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 * Check if a given node is the operand of mutation unary operator.
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 * @param {ASTNode} node The node to check.
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 * @returns {boolean} `true` if the node is the operand of mutation unary operator.
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 */
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function isOperandOfMutationUnaryOperator(node) {
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    const argumentNode = node.parent.type === "ChainExpression"
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        ? node.parent
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        : node;
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    const { parent } = argumentNode;
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    return (
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        (
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            parent.type === "UpdateExpression" &&
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            parent.argument === argumentNode
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        ) ||
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        (
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            parent.type === "UnaryExpression" &&
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            parent.operator === "delete" &&
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            parent.argument === argumentNode
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        )
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    );
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}
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/**
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 * Check if a given node is the iteration variable of `for-in`/`for-of` syntax.
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 * @param {ASTNode} node The node to check.
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 * @returns {boolean} `true` if the node is the iteration variable.
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 */
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function isIterationVariable(node) {
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    const { parent } = node;
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    return (
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        (
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            parent.type === "ForInStatement" &&
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            parent.left === node
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        ) ||
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        (
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            parent.type === "ForOfStatement" &&
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            parent.left === node
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        )
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    );
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}
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/**
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 * Check if a given node is at the first argument of a well-known mutation function.
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 * - `Object.assign`
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 * - `Object.defineProperty`
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 * - `Object.defineProperties`
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 * - `Object.freeze`
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 * - `Object.setPrototypeOf`
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 * - `Reflect.defineProperty`
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 * - `Reflect.deleteProperty`
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 * - `Reflect.set`
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 * - `Reflect.setPrototypeOf`
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 * @param {ASTNode} node The node to check.
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 * @param {Scope} scope A `escope.Scope` object to find variable (whichever).
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 * @returns {boolean} `true` if the node is at the first argument of a well-known mutation function.
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 */
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function isArgumentOfWellKnownMutationFunction(node, scope) {
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    const { parent } = node;
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    if (parent.type !== "CallExpression" || parent.arguments[0] !== node) {
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        return false;
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    }
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    const callee = astUtils.skipChainExpression(parent.callee);
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    if (
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        !astUtils.isSpecificMemberAccess(callee, "Object", WellKnownMutationFunctions.Object) &&
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        !astUtils.isSpecificMemberAccess(callee, "Reflect", WellKnownMutationFunctions.Reflect)
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    ) {
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        return false;
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    }
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    const variable = findVariable(scope, callee.object);
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    return variable !== null && variable.scope.type === "global";
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}
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/**
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 * Check if the identifier node is placed at to update members.
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 * @param {ASTNode} id The Identifier node to check.
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 * @param {Scope} scope A `escope.Scope` object to find variable (whichever).
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 * @returns {boolean} `true` if the member of `id` was updated.
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 */
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function isMemberWrite(id, scope) {
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    const { parent } = id;
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    return (
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        (
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            parent.type === "MemberExpression" &&
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            parent.object === id &&
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            (
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                isAssignmentLeft(parent) ||
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                isOperandOfMutationUnaryOperator(parent) ||
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                isIterationVariable(parent)
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            )
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        ) ||
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        isArgumentOfWellKnownMutationFunction(id, scope)
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    );
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}
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/**
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 * Get the mutation node.
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 * @param {ASTNode} id The Identifier node to get.
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 * @returns {ASTNode} The mutation node.
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 */
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function getWriteNode(id) {
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    let node = id.parent;
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    while (
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        node &&
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        node.type !== "AssignmentExpression" &&
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        node.type !== "UpdateExpression" &&
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        node.type !== "UnaryExpression" &&
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        node.type !== "CallExpression" &&
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        node.type !== "ForInStatement" &&
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        node.type !== "ForOfStatement"
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    ) {
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        node = node.parent;
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    }
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    return node || id;
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}
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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    meta: {
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        type: "problem",
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        docs: {
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            description: "Disallow assigning to imported bindings",
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            recommended: true,
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            url: "https://eslint.org/docs/latest/rules/no-import-assign"
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        },
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        schema: [],
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        messages: {
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            readonly: "'{{name}}' is read-only.",
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            readonlyMember: "The members of '{{name}}' are read-only."
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        }
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    },
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    create(context) {
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        const sourceCode = context.sourceCode;
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        return {
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            ImportDeclaration(node) {
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                const scope = sourceCode.getScope(node);
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                for (const variable of sourceCode.getDeclaredVariables(node)) {
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                    const shouldCheckMembers = variable.defs.some(
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                        d => d.node.type === "ImportNamespaceSpecifier"
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                    );
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                    let prevIdNode = null;
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                    for (const reference of variable.references) {
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                        const idNode = reference.identifier;
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                        /*
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                         * AssignmentPattern (e.g. `[a = 0] = b`) makes two write
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                         * references for the same identifier. This should skip
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                         * the one of the two in order to prevent redundant reports.
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                         */
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                        if (idNode === prevIdNode) {
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                            continue;
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                        }
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                        prevIdNode = idNode;
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                        if (reference.isWrite()) {
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                            context.report({
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                                node: getWriteNode(idNode),
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                                messageId: "readonly",
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                                data: { name: idNode.name }
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                            });
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                        } else if (shouldCheckMembers && isMemberWrite(idNode, scope)) {
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                            context.report({
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                                node: getWriteNode(idNode),
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                                messageId: "readonlyMember",
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                                data: { name: idNode.name }
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                            });
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                        }
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                    }
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                }
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            }
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        };
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    }
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};
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