Fix: Remove warning in initialized variables (fixes #12687)

CHANGELOG.md

@@ -2742,7 +2742,7 @@ v3.16.0 - February 20, 2017
 * c7e64f3 Upgrade: mock-fs (#8070) (Toru Nagashima)
 * acc3301 Update: handle uncommon linebreaks consistently in rules (fixes #7949) (#8049) (Teddy Katz)
 * 591b74a Chore: enable operator-linebreak on ESLint codebase (#8064) (Teddy Katz)
-* 6445d2a Docs: Add documentation for /* exported */ (fixes #7998) (#8065) (Lee Yi Min)
+* 6445d2a Docs: Add documentation for /*exported*/ (fixes #7998) (#8065) (Lee Yi Min)
 * fcc38db Chore: simplify and improve performance for autofix (#8035) (Toru Nagashima)
 * b04fde7 Chore: improve performance of SourceCode constructor (#8054) (Teddy Katz)
 * 90fd555 Update: improve null detection in eqeqeq for ES6 regexes (fixes #8020) (#8042) (Teddy Katz)
@@ -6358,7 +6358,7 @@ v0.0.9 - October 5, 2013
 * Rule: no-loop-func (Ilya Volodin)
 * Merge branch 'master' of https://github.com/nzakas/eslint into no-underscore-dangle (Matt DuVall)
 * Use proper node declarations and __proto__ exception (Matt DuVall)
-* Updating no-undef patch (see pull request #164) - Simplify parseBoolean() - Make knowledge of```/*jshint*/``` and ```/*global */``` internal to eslint object - Put user-declared globals in Program scope (Mark Macdonald)
+* Updating no-undef patch (see pull request #164) - Simplify parseBoolean() - Make knowledge of```/*jshint*/``` and ```/*global*/``` internal to eslint object - Put user-declared globals in Program scope (Mark Macdonald)
 * Rule: no-eq-null (Ian Christian Myers)
 * fixed broken merge (Raphael Pigulla)
 * fixes #143 (Raphael Pigulla)
@@ -6367,7 +6367,7 @@ v0.0.9 - October 5, 2013
 * Update eslint.json with no-underscore-dangle rule (Matt DuVall)
 * Rule: no-underscore-dangle for func/var declarations (Matt DuVall)
 * Warn on finding the bitwise NOT operator (James Allardice)
-* Updating no-undef patch (see pull request #164) 3. Move parsing of ```/*global */``` and ```/*jshint */``` to eslint.js (Mark Macdonald)
+* Updating no-undef patch (see pull request #164) 3. Move parsing of ```/*global*/``` and ```/*jshint*/``` to eslint.js (Mark Macdonald)
 * Warn on finding a bitwise shift operator (fixes #170) (James Allardice)
 * Fix broken test (James Allardice)
 * Add support for the do-while statement to the curly rule (closes #167) (James Allardice)

lib/rules/no-shadow.js

@@ -11,6 +11,16 @@
 
 const astUtils = require("./utils/ast-utils");
 
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const INIT_NODE_TYPES = [
+    "AssignmentPattern",
+    "ForInStatement",
+    "ForOfStatement"
+];
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -57,6 +67,70 @@ module.exports = {
             allow: (context.options[0] && context.options[0].allow) || []
         };
 
+        /**
+         * @callback CheckNodeCallback
+         * @param {ASTNode} node A node to check.
+         */
+
+        /**
+         * Traverses AST from a given node to find a node that verifies checkNodeCB condition.
+         * @param {ASTNode} node a node to get.
+         * @param {CheckNodeCallback} checkNodeCB a callback that checks whether or not the node verifies its condition or not.
+         * @returns {ASTNode} the node that verifies checkNodeCB condition.
+         */
+        function getNode(node, checkNodeCB) {
+            let currentNode = node;
+
+            while (currentNode && !checkNodeCB(currentNode)) {
+                currentNode = currentNode.parent;
+            }
+            return currentNode;
+        }
+
+        /**
+         * Checks if a variable and a shadowedVariable have the same init pattern node parent.
+         * @param {Object} variable a variable to check.
+         * @param {Object} shadowedVariable a shadowedVariable to check.
+         * @returns {boolean} Whether or not the variable and the shadowedVariable have the same init pattern node parent.
+         */
+        function areOnInitPatternNode(variable, shadowedVariable) {
+            const outerDef = shadowedVariable.defs[0];
+            const innerDef = variable.defs[0];
+
+            const callExpressionNode = getNode(
+                innerDef.node,
+                node => node.type === "CallExpression"
+            );
+
+            if (callExpressionNode) {
+                const initNode1 = getNode(
+                    outerDef && outerDef.name && outerDef.name.parent,
+                    node => {
+                        const { type, init, right } = node;
+                        let nodeType;
+
+                        if (type === "VariableDeclarator" && init) {
+                            nodeType = node.init.type;
+                        }
+                        if (INIT_NODE_TYPES.includes(type)) {
+                            nodeType = right.type;
+                        }
+                        return nodeType === "CallExpression";
+                    }
+                );
+
+                const initNode2 = getNode(
+                    callExpressionNode,
+                    node => node === initNode1
+                );
+
+                if (initNode2) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         /**
          * Check if variable name is allowed.
          * @param  {ASTNode} variable The variable to check.
@@ -186,7 +260,7 @@ module.exports = {
 
                 if (shadowed &&
                     (shadowed.identifiers.length > 0 || (options.builtinGlobals && "writeable" in shadowed)) &&
-                    !isOnInitializer(variable, shadowed) &&
+                    !isOnInitializer(variable, shadowed) && !areOnInitPatternNode(variable, shadowed) &&
                     !(options.hoist !== "all" && isInTdz(variable, shadowed))
                 ) {
                     const location = getDeclaredLocation(shadowed);

tests/lib/rules/no-shadow.js

@@ -58,7 +58,16 @@ ruleTester.run("no-shadow", rule, {
         { code: "var Object = 0;", options: [{ builtinGlobals: true }] },
         { code: "var top = 0;", options: [{ builtinGlobals: true }], env: { browser: true } },
         { code: "function foo(cb) { (function (cb) { cb(42); })(cb); }", options: [{ allow: ["cb"] }] },
-        { code: "class C { foo; foo() { let foo; } }", parserOptions: { ecmaVersion: 2022 } }
+        { code: "class C { foo; foo() { let foo; } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "const a = [].find(a=>a)", parserOptions: { ecmaVersion: 6 } },
+        { code: "const [a = [].find(a => true)] = dummy", parserOptions: { ecmaVersion: 6 } },
+        { code: "const { a = [].find(a => true) } = dummy", parserOptions: { ecmaVersion: 6 } },
+        { code: "function func(a = [].find(a => true)) {}", parserOptions: { ecmaVersion: 6 } },
+        { code: "for (const a in [].find(a => true)) {}", parserOptions: { ecmaVersion: 6 } },
+        { code: "for (const a of [].find(a => true)) {}", parserOptions: { ecmaVersion: 6 } },
+        { code: "const a = [].map(a => true).filter(a => a === 'b')", parserOptions: { ecmaVersion: 6 } },
+        { code: "const { a } = (({ a }) => ({ a }))();", parserOptions: { ecmaVersion: 6 } },
+        { code: "const person = people.find(item => {const person = item.name; return person === 'ahmed'})", parserOptions: { ecmaVersion: 6 } }
     ],
     invalid: [
         {