436731 - multiple destructuring forms in function param list

Status: RESOLVED FIXED

(Rhino Graveyard :: Core, defect)

Description

[Steve Yegge]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.14) Gecko/20080404 Firefox/2.0.0.14
Build Identifier: Rhino 1.7 release 1 2008 03 06

You can define a function with multiple destructuring-forms as parameters, but calling the function results in a TypeError.

Reproducible: Always

Steps to Reproduce:
SpiderMonkey:

js> function foo([a, b], [c, d]) {print(a); print(b); print(c); print(d);}
js> foo([1, 2], [3, 4])
1
2
3
4

Rhino 1.7R1 (and also R2/trunk):

js> function foo([a, b], [c, d]) {print(a); print(b); print(c); print(d);}
js> foo([1, 2], [3, 4])
js: "<stdin>", line 2: uncaught JavaScript runtime exception: TypeError: Cannot read property "0" from undefined
	at <stdin>:2 (foo)
	at <stdin>:3

Actual Results:  
TypeError:  cannot read property "0" from undefined

Expected Results:  
See details field for SpiderMonkey behavior.

Comment 1

[Hannes Wallnoefer]

Attachment: Delay creation of destructuring assignment helpers

The problem is that destructuring assignment helpers are created while still parsing the parameters and before the function body has been parsed. Therefore they somehow trash the function scope. I guess it's because of their wrong parent scope, but I'm not completely sure. This patch fixes the problem.

Comment 2

[Hannes Wallnoefer]

Attachment: Updated patch

Update patch to refactored Parser code.

Comment 3

[Hannes Wallnoefer]

Committed patch to CVS HEAD.

Checking in src/org/mozilla/javascript/Parser.java;
/cvsroot/mozilla/js/rhino/src/org/mozilla/javascript/Parser.java,v  <--  Parser.java
new revision: 1.136; previous revision: 1.135
done