[Caml-list] Second release candidate for OCaml 5.1.0

[Florian Angeletti <florian.angeletti@inria.fr>]

Dear OCaml users,

In the last two weeks, two significant bugs have been discovered in the release candidate for OCaml 5.1.0 (one affecting the type system, another in the runtime).

Those bugs are now fixed and we are publishing a second release candidate to check that everything is in order before the release in the upcoming week.

If you find any bugs, please report them on OCaml's issue tracker (https://github.com/ocaml/ocaml/issues).

The full change log for OCaml 5.1.0 is available on GitHub (https://github.com/ocaml/ocaml/blob/5.1/Changes).
A short summary of the two bug fixes in this release candidate is also available below.

Happy hacking,
Florian Angeletti for the OCaml team.

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Installation Instructions

The base compiler can be installed as an opam switch with the following commands on opam 2.1 and later:

    opam update
    opam switch create 5.1.0~rc2

The source code for the release candidate is also directly available on:

* GitHub : https://github.com/ocaml/ocaml/archive/5.1.0-rc2.tar.gz
* OCaml archives at Inria : https://caml.inria.fr/pub/distrib/ocaml-5.1/ocaml-5.1.0~rc2.tar.gz

If you want to tweak the configuration of the compiler, you can switch to the option variant with:

    opam update
    opam switch create <switch_name> ocaml-variants.5.1.0~rc2+options <option_list>

where `<option_list>` is a comma-separated list of `ocaml-option-*` packages. For instance, for a `flambda` and `no-flat-float-array` switch:

    opam switch create 5.1.0~rc2+flambda+nffa ocaml-variants.5.1.0~rc2+options ocaml-option-flambda ocaml-option-no-flat-float-array

All available options can be listed with `opam search ocaml-option`.

-------------------------

## Last Minute Bug Fixes in the rc2

### Type System:

* (*breaking change*) [#6941](https://github.com/ocaml/ocaml/issues/6941), [#11187](https://github.com/ocaml/ocaml/issues/11187), +[#12483](https://github.com/ocaml/ocaml/issues/12483): prohibit using classes through recursive modules
   inheriting or including a class belonging to a mutually-recursive module
   would previous behave incorrectly, and now results in a clean error.
   (Leo White, review by Gabriel Scherer and Florian Angeletti)

### Runtime

- [#12481](https://github.com/ocaml/ocaml/issues/12481), [#12505](https://github.com/ocaml/ocaml/issues/12505): Fix incorrect initialization of array expressions
  `[|e1;...;eN|]` when `N` is large enough to require major heap allocation.
  (Xavier Leroy, report by Andrey Popp, analysis by KC Sivaramakrishnan
   and Vincent Laviron, review by Gabriel Scherer)