1155141 - Object destructuring form is no longer valid

Status: RESOLVED DUPLICATE of bug 1146136

(Core :: JavaScript Engine, defect)

Description

[Kyle Simpson]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:39.0) Gecko/20100101 Firefox/39.0
Build ID: 20150312030248

Steps to reproduce:

This form used to be valid in ES6, but it was recently clarified:

var a, b;
( {a,b} ) = {a:1,b:2};

Parenthesized left-hand expressions are not allowed with the object destructuring form. Instead, you're now required to do:

var a, b;
( {a,b} = {a:1,b:2} );

The parenthesized left-hand expression form is disallowed for destructuring, but for compat sake it's kept for normal assignments:

var a;
(a) = 2;  // still valid