Disallow destructuring in legacy sloppy for-in loop parsing

Disallow destructuring in legacy sloppy for-in loop parsing

For web compat reasons, we support an initializer in the declaration
part of a for-in loop. But we should disallow this for destructured
declarations (just as we do for lexical declarations). In fact, without
disallowing it, we crash.

Also fix up the PreParser to have the same restrictions here as the parser
(the lexical check was missing there), verified by running the message tests
with --min-preparse-length=0.

In fixing the logic I've also cleaned up the code a bit, removing the
only-called-once DeclarationParsingResult::SingleName method.

BUG=v8:811
LOG=n

Committed: https://crrev.com/ceb92ebfdfb561d71038793c02b42aa973f55ec4
Cr-Commit-Position: refs/heads/master@{#32236}

[adamk, 2015-11-24 19:46:03]

adamk@chromium.org changed reviewers:
+ littledan@chromium.org

[Dan Ehrenberg, 2015-11-25 01:02:59]

lgtm

https://codereview.chromium.org/1471973003/diff/20001/src/preparser.cc
File src/preparser.cc (right):

https://codereview.chromium.org/1471973003/diff/20001/src/preparser.cc#newcod...
src/preparser.cc:529: bool is_pattern = false;
Nit: Not sure why you moved the initialization up here; it seemed marginally
clearer before.

[adamk, 2015-11-25 01:13:12]

Thanks for the quick review!

https://codereview.chromium.org/1471973003/diff/20001/src/preparser.cc
File src/preparser.cc (right):

https://codereview.chromium.org/1471973003/diff/20001/src/preparser.cc#newcod...
src/preparser.cc:529: bool is_pattern = false;
On 2015/11/25 01:02:58, Dan Ehrenberg wrote:
> Nit: Not sure why you moved the initialization up here; it seemed marginally
> clearer before.

I moved this up to put the passing to the out-param in the same place as the
other out params (the old declaration was in an inner block).

[adamk, 2015-11-25 01:13:16]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2015-11-25 01:13:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1471973003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1471973003/20001

[commit-bot: I haz the power, 2015-11-25 01:15:04]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-25 01:15:33]

Patchset 2 (id:??) landed as
https://crrev.com/ceb92ebfdfb561d71038793c02b42aa973f55ec4
Cr-Commit-Position: refs/heads/master@{#32236}