901987 - for-of loops do not accept initialisers and are restricted to assignment expressions

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[André Bargull [:anba]]

The following for-of loops should both throw a SyntaxError:
---
for (var v=0 of [1]) print(v)
for (var v of [1],[2],[3]) print(v)
---

(1) for-of loops do not accept an initialiser expression
(2) for-of loops only allow assignment expressions as their RHS

Comment 1

[André Bargull [:anba]]

Background:
https://bugs.ecmascript.org/show_bug.cgi?id=1163
http://wiki.ecmascript.org/doku.php?id=strawman:simultaneous_iteration

Comment 2

[Andy Wingo [:wingo]]

Attachment: The RHS of a for-of loop is an assignment expression

Comment 3

[Andy Wingo [:wingo]]

I should note that the first part of this bug is already fixed and tested by jit-test for-of/syntax-3.js.

Comment 4

[Jason Orendorff [:jorendorff]]

Comment on attachment 8388411 [details] [diff] [review]
The RHS of a for-of loop is an assignment expression

Review of attachment 8388411 [details] [diff] [review]:
-----------------------------------------------------------------

Thanks.

Comment 5

[Andy Wingo [:wingo]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/39f411171c6f

Comment 6

[(PTO June 19-July 7) Ryan VanderMeulen]

https://hg.mozilla.org/mozilla-central/rev/39f411171c6f