744501 - Variables declared with 'var [...]' have wrong scopes.

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[spammed.user]

Run the following code:

function x(){var a=1;x=function(){return a;};return a;}
alert(x());
alert(x());

It alerts '1' twice, as it should. However,

function x(){var [a]=[1];x=function(){return a;};return a;}
alert(x());
alert(x());

alerts '1' and then 'undefined'. Also,

function x(){var a=1;x=function(){return a;};return a;}
alert(x());
alert(x());
function x(){var [a]=[1];x=function(){return a;};return a;}
alert(x());
alert(x());

alerts '1', 'undefined', 'undefined', 'undefined', whereas

function x(){var [a]=[1];x=function(){return a;};return a;}
alert(x());
alert(x());
function x(){var a=1;x=function(){return a;};return a;}
alert(x());
alert(x());

works properly – it alerts 4 '1's.

Comment 1

[Luke Wagner [:luke]]

Oops, repros on trunk, not caused by 740259.

Comment 2

[Luke Wagner [:luke]]

Oh, wow, what coincidence: this bug is actually *fixed* by bug 740259 !  (Bug 740259 added some strong asserts that caught a bug in group assignment where we forgot to call MaybeEmitVarDecl.)

(It looks like the patch isn't in Nightly yet, but it should be very soon.)  Thanks for reporting!