Fix: no-param-reassign false positive on destructuring (fixes #8279) (#8281)

* Fix: no-param-reassign false positive on destructuring (fixes #8279)

This updates no-param-reassign to stop traversing up the AST if it encounters a Property node where the variable reference is part of the key.

* Add test for object shorthand destructuring

Author: not-an-aardvark

lib/rules/no-param-reassign.js

@@ -96,8 +96,15 @@ module.exports = {
                         }
                         break;
 
-                    default:
+                    // EXCLUDES: e.g. ({ [foo]: a }) = bar;
+                    case "Property":
+                        if (parent.key === node) {
+                            return false;
+                        }
+
                         break;
+
+                    // no default
                 }
 
                 node = parent;

tests/lib/rules/no-param-reassign.js

@@ -35,7 +35,12 @@ ruleTester.run("no-param-reassign", rule, {
         { code: "function foo(a) { ++a.b; }", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
         { code: "function foo(a) { delete a.b; }", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
         { code: "function foo(a, z) { a.b = 0; x.y = 0; }", options: [{ props: true, ignorePropertyModificationsFor: ["a", "x"] }] },
-        { code: "function foo(a) { a.b.c = 0;}", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] }
+        { code: "function foo(a) { a.b.c = 0;}", options: [{ props: true, ignorePropertyModificationsFor: ["a"] }] },
+        {
+            code: "function foo(a) { ({ [a]: variable }) = value }",
+            options: [{ props: true }],
+            parserOptions: { ecmaVersion: 6 }
+        }
     ],
 
     invalid: [
@@ -82,6 +87,18 @@ ruleTester.run("no-param-reassign", rule, {
             parserOptions: { ecmaVersion: 6 },
             options: [{ props: true, ignorePropertyModificationsFor: ["a"] }],
             errors: [{ message: "Assignment to property of function parameter 'bar'." }]
+        },
+        {
+            code: "function foo(bar) { ({foo: bar.a} = {}); }",
+            parserOptions: { ecmaVersion: 6 },
+            options: [{ props: true }],
+            errors: [{ message: "Assignment to property of function parameter 'bar'." }]
+        },
+        {
+            code: "function foo(a) { ({a} = obj); }",
+            parserOptions: { ecmaVersion: 6 },
+            options: [{ props: true }],
+            errors: [{ message: "Assignment to function parameter 'a'." }]
         }
     ]
 });