514576 - ES5 strict mode: no 'with' statements permitted in strict mode code

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jim Blandy :jimb]

From ES5 Annex C:

Strict mode code may not include a WithStatement. The occurrence of a WithStatement in such a context is an SyntaxError (12.10).

Comment 1

[Jim Blandy :jimb]

Hmm.  Back in bug 322430, we decided that warnings about 'with' statements were misguided with JSOPTION_STRICT enabled.  ES5 strict mode forbids 'with' statements.  How should a unified strictness regime behave?

Comment 2

[Brendan Eich [:brendan]]

Sorry, my memory fails me, but can you remind me of the separate bit somewhere that indicates ES5 strict mode (a static property of JSScript, presumably a new bitfield). That plus JSOPTION_STRICT could enable the warning, whereas just JSOPTION_STRICT would not. Then you pick your poison with option-setting and/or "use strict".

/be

Comment 3

[Jim Blandy :jimb]

Attachment: Forbid 'with' statements in strict mode code.

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

Comment on attachment 404910 [details] [diff] [review]
Forbid 'with' statements in strict mode code.

I like this patch so much, I'm going to give it 2 +s. However, I do have a nitpick:
>+            return NULL;
>+        }
>         pn = NewParseNode(PN_BINARY, tc);

Please add  a newline before this assignment.

Comment 5

[Jim Blandy :jimb]

(In reply to comment #4)
> (From update of attachment 404910 [details] [diff] [review])
> I like this patch so much, I'm going to give it 2 +s.

:)

> However, I do have a
> nitpick:
> >+            return NULL;
> >+        }
> >         pn = NewParseNode(PN_BINARY, tc);
> 
> Please add  a newline before this assignment.

Fixed --- thanks!

Comment 6

[Jim Blandy :jimb]

Attachment: Forbid 'with' statements in strict mode code.

Code unchanged; just added tests.

Comment 7

[Jim Blandy :jimb]

Attachment: Forbid 'with' statements in strict mode code.

Revised tests per jorendorff's and waldo's comments.

Comment 8

[Jim Blandy :jimb]

http://hg.mozilla.org/tracemonkey/rev/80bdd2d441d1

Comment 9

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/80bdd2d441d1