Fix potential GC issue while iterating over weak refs

While walking over the list of subclasses for `include` and friends, we
check whether the subclass is a garbage object. After the check, we
allocate objects which might trigger GC and make the subclass garbage,
even though before the allocation the subclass was not garbage. This is
a sort of time-of-check-time-of-use issue.

Fix this by saving the weak reference to a local variable, upgrading it
to a strong reference while we do the allocation. It makes the code look
slightly nicer even if it doesn't fix any runtime issues.

0 files changed, 0 insertions, 0 deletions