ppxlib 5.2 trunk-support needs value_constraint support

[avsm]

Since ocaml/ocaml@ba57d5212a, the trunk-support branch fails to build due to ocaml/ocaml#12188 changing how coercion on value bindings work.

[pitag-ha]

I'm working on that. Adding support for value binding coercions was straight-forward, but by doing so, I've noticed that our migrations of value binding constraints already seem to be wrong, so it's taking a bit longer. I can see if I already push something that compiles on 5.1 and 5.2 today, even if it won't do the right migrations. That would also be helpful for @Sudha247 and @shym, wouldn't it?

[pitag-ha]

@avsm, @Sudha247, @shym and @nojb, you can pin to panglesd:fix-418, if you already need 5.1.0~alpha2 or 5.2.0+trunk support (now that I've said that, I won't force push to it anymore). We'll probably merge the branch beginning of next week some time soon, so then our trunk-support will be working again.

[Sudha247]

Thanks! cc @punchagan relevant for ocaml-bench/sandmark#453.

[avsm]

@pitag-ha your speed of response is faster than light! Thanks very much indeed -- your branch above unblocked me while testing the ppc64/ocaml5 PR.

[shym]

@pitag-ha I had a quick glance at that branch (probably too short to count as proper review, but still), I really like its testing, very nice!

[pitag-ha]

The trunk-support branch is now compatible both with ocaml.5.1.0~alpha2 and with ocaml.5.2.0+trunk.