866624 - Duplicate property keys in destructuring form throws SyntaxError in strict-mode

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[André Bargull [:anba]]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0
Build ID: 20130409194949

Steps to reproduce:

test case:
js> "use strict"; var {a:a1,a:a2} = {}
typein:4:0 SyntaxError: property name a appears more than once in object literal:
typein:4:0 "use strict"; var {a:a1,a:a2} = {}
typein:4:0 ..........................^
js> "use strict"; ({a:a1,a:a2}) = {}
typein:5:0 SyntaxError: property name a appears more than once in object literal:
typein:5:0 "use strict"; ({a:a1,a:a2}) = {}
typein:5:0 .......................^


Both forms are allowed by the ES6 draft. Duplicate property keys checks (see Static Semantics: Early Errors, 11.1.5  Object Initialiser) only have to be performed for object initialisers, not for destructing forms (destructuring assignment / destructuring binding patterns).

Comment 1

[André Bargull [:anba]]

No longer reproducible - resolving as WFM. (Probably fixed as a side-effect of allowing duplicate properties - bug 1041128.)