350810 - Incorrect decompilation for "let" in lvalue part of for..in

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P2)

Description

[Jesse Ruderman]

> function () { for ((let (x = 3) y)[5] in []) { } }
function () { for ((let (3 = 3) y)[5] in []) { } }

Like in bug 349493 and bug 350288, incorrect decompilation gives "let (3 = 3)".

Comment 1

[Brendan Eich [:brendan]]

Attachment: decompiler can't cheat and not preserve the compiler's stack model

I added a missing error check (todo < 0 => return false) that should have been in the last patch to jsopcode.c.

/be

Comment 2

[Brendan Eich [:brendan]]

Checking in jsopcode.c;
/cvsroot/mozilla/js/src/jsopcode.c,v  <--  jsopcode.c
new revision: 3.152; previous revision: 3.151
done

Fixed on trunk.

/be

Comment 3

[Brendan Eich [:brendan]]

Comment on attachment 236258 [details] [diff] [review]
decompiler can't cheat and not preserve the compiler's stack model

This is pretty important for js1.7, since it adds local let-bound or catch-bound variables that require exact stack modeling, for code generation and for decompilation.  This bug is only in the decompiler, not in the code generator, but the decompiler counts too!

/be

Comment 4

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

Comment on attachment 236258 [details] [diff] [review]
decompiler can't cheat and not preserve the compiler's stack model

a=beltzner on behalf of 181drivers

Comment 5

[Bob Clary [:bc] (inactive)]

Checking in regress-350810.js;
/cvsroot/mozilla/js/tests/js1_7/block/regress-350810.js,v  <--  regress-350810.js
initial revision: 1.1

Comment 6

[Brendan Eich [:brendan]]

Fixed on the 1.8 branch.

/be

Comment 7

[Bob Clary [:bc] (inactive)]

verified fixed 1.8, 1.9 2006090118 windows/mac*/linux