Flexbox: Link to containing block not established; perhaps you forgot to call `set_absolute_descendants`

[paulrouget]

thread 'LayoutWorker worker 3/3' panicked at 'Link to containing block not established; perhaps you forgot to call `set_absolute_descendants`?', /Users/paul/github/servo/components/layout/flow.rs:1411

<div style="display:flex;position:absolute">
  abc
</div>

Requires #7331.

[paulrouget]

Happens when position:absolute/relative is used inside a flex element.

[pcwalton]

Should be fairly easy to fix; the probable fix is right in the error message :)

[aidanhs]

Can't reproduce with provided testcase, but http://maps.google.com in release mode does do it.
(UK gmaps crashes servo with a different error in dev mode).

[jdm]

@aidanhs: You likely need to run with --pref layout.flex.enabled to reproduce the crash.

[shinglyu]

I can't reproduce the crash by running ./mach run -d --pref layout.flex.enabled --pref layout.flex-direction.enabled, also tried --release. Is this solved by some previous patch?

[jdm]

Seems likely!