347593 - For-each loop with destructuring assignment is performed as for loop

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P1)

Description

[nanto_vi (TOYAMA Nao)]

If destructuring assignment is used in for-each loop, the loop incorrectly iterates over the object as if it is for loop.

js> for (let [, { a: b }] in [{ a: 2 }, { a: 3 }]) print(b); // OK
2
3
js> for each (let { a: b } in [{ a: 2 }, { a: 3 }]) print(b); // Wrong
undefined
undefined
js> for each (let [, { a: b }] in [{ a: 2 }, { a: 3 }]) print(b); // Wrong
2
3

In the example above, the second loop should show 2 and 3 and the third loop should throw a TypeError exception.

Comment 1

[Brendan Eich [:brendan]]

Fast action needed for beta 2.

/be

Comment 2

[Brendan Eich [:brendan]]

Attachment: fix

Small fix to get js1.7 semantics right regarding for (i in o) vs. for each (v in o) key (identifier) vs. property value enumeration, in combination with the new destructuring assignment support (for ([k,v] in o) to destructure key-value pairs vs. for each ({vp1:x, vp2:y} in o) to destructure properties of the value, vp1 and vp2 in this example).

/be

Comment 3

[Brendan Eich [:brendan]]

Fixed on trunk.

/be

Comment 4

[Bob Clary [:bc] (inactive)]

Checking in regress-347593.js;
/cvsroot/mozilla/js/tests/js1_7/geniter/regress-347593.js,v  <--  regress-347593.js
initial revision: 1.1

Comment 5

[Mike Beltzner [:beltzner, not reading bugmail]]

Comment on attachment 232582 [details] [diff] [review]
fix

a=drivers

Comment 6

[Brendan Eich [:brendan]]

Fixed on the 1.8 branch too.

/be

Comment 7

[Bob Clary [:bc] (inactive)]

verified fixed 1.9 win/mac(ppc|tel)/linux 20060808

Comment 8

[Bob Clary [:bc] (inactive)]

verified fixed 1.8 20060809 mac(ppc|tel)/linux. Unfortunately I don't have
windows test results for 20060809 1.8, but verifying anyway.