Rewind additional parser state when reinterpreting arrow arguments

Rewind additional parser state when reinterpreting arrow arguments

The new ParserCheckpoint mechanism resets some state, notably the
bailout ID counter but also some statement counters (only applicable
once we get "do" expressions) when we decide to reinterpret a comma
expression as arrow function arguments.

R=rossberg@chromium.org, marja@chromium.org
BUG=v8:3475
LOG=N

Committed: https://code.google.com/p/v8/source/detail?r=22925

[wingo, 2014-08-06 10:49:43]

The C++ error (not caught by GCC?) was that you couldn't "friend class Foo"
where Foo was a typedef.  A strange restriction!  Anyway, this patch does the
simple thing and inlines the Checkpoint class definition into the ParserTraits /
PreParserTraits.  PTAL.

[rossberg, 2014-08-06 11:41:37]

On 2014/08/06 10:49:43, wingo wrote:
> The C++ error (not caught by GCC?) was that you couldn't "friend class Foo"
> where Foo was a typedef.  A strange restriction!

You also cannot forward-declare a typedef. C++ is a grab bag of arbitrary
restrictions and behaviours.

> Anyway, this patch does the
> simple thing and inlines the Checkpoint class definition into the ParserTraits
/
> PreParserTraits.  PTAL.

LGTM

[Sven Panne, 2014-08-06 12:03:04]

Well, with C++11 you *can* use typedef with "friend", but to keep things
interesting, you'll have to leave out "class" then, e.g. "friend MyTypedef;".
:-]

[wingo, 2014-08-06 12:05:46]

Committed patchset #2 manually as 22925 (presubmit successful).