722021 - Assertion failure: key.index() >= 0, at methodjit/BaseAssembler.h:788

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Christian Holler (:decoder)]

The following test asserts on mozilla-central revision 8a59519e137e (options -m -n -a):


var a = [];
for (let j = 0; j < 5; ++j) {
    a.push(-2 in (a));
}


S-s because this seems to be some length/offset guarding assertion in methodjit, so I'd assume this could go worse than just asserting.

Comment 1

[Daniel Veditz [:dveditz]]

Is this a regression?

Comment 2

[Brian Hackett [Laid off!]]

Attachment: patch

It looks like this is due to bug 664824, so a recent regression.  An unsigned comparison is being used (as is done for all other uses of guardArrayExtent) so behavior should be correct, I think this assert is bogus.

Comment 3

[Brian Hackett [Laid off!]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/b8252a1c0de6

Comment 4

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/b8252a1c0de6

Comment 5

[Christian Holler (:decoder)]

Automatically extracted testcase for this bug was committed:

https://hg.mozilla.org/mozilla-central/rev/efaf8960a929