Downgrade iso and trn to ref when replacing this in a box method.

[plietar]

Fixes #1887

[jemc]

@plietar - did you come to a conclusion about this concern from this comment (#1887 (comment))?

Worth noting, this may interact with (auto) recovery, such that despite decaying to ref you can still get an iso back.

[Praetonus]

This needs an ast_free call with orig if downcast_iso_trn_receiver_to_ref did a copy, as deferred_reify_new also does a copy. Another possibility would be to add a new version of deferred_reify_new that doesn't copy the AST for the this type and use it in that case.

[jemc]

This has been stalled for a while, and I'd like to see it move forward to fix the soundness issue.

@plietar - can you add the requested ast_free, or if you don't have time to do it, let us know that and maybe someone else can take over bringing this to completion?

(It also has merge conflicts at this point, but those look simple to resolve).

[dipinhora]

@plietar due to the recent releases and their related changes to the CHANGELOG file, please merge or rebase onto master and adjust your CHANGELOG entries into the appropriate area of "unreleased" in the CHANGELOG file.

[dipinhora]

@plietar due to the release of 0.24.1 and its related changes to the CHANGELOG file, please merge or rebase onto master and adjust your CHANGELOG entries into the appropriate area of "unreleased" in the CHANGELOG file.

[mfelsche]

@plietar or anyone else in @ponylang/committer we have another user hitting an issue that is related to #1875 which has a fix #1888 but we agreed on fixing #1887 first.

The related new issue is #2881

How are the chances someone finds time for this one?
Or @plietar or @Praetonus would anyone of you have 5 minutes left to explain to someone like me (in here or IRC or slack) what needs to be done to finish this up, so I can proceed on this one?

[jemc]

Discussed this in today's sync call. @sylvanc reasoned that this does not cause problems with auto-recovery, and ratified the change.

All this needs is the missing ast_free, and to fix merge conflicts then it can be merged.

[mfelsche]

I took the freedom to rebase this branch onto current master and add the ast_free @Praetonus mentioned and pushed that to your form @plietar

[jemc]

Fixed the CHANGELOG merge conflict. Letting the CI run to see how it does against latest masterchanges, then this is ready to merge.

[mfelsche]

Thanks @jemc !

Everything is green, merging.