OCaml 5.3.0 - Second Beta
One month after the release of the first beta for OCaml 5.3.0, we are releasing a second and hopefully last beta release for OCaml 5.3.0 .
The most notable changes for this second beta are probably a handful of type system bugfixes. In particular, those fixes revert a change of behaviour in the first beta when pattern matching GADTs with non-injective type parameters.
We also have a C++ header compatibility fix and the restoration of some configuration variable in Makefiles for the sake of backward compatibility.
Overall, the release is converging and we are expecting to have a first release candidate around the middle of December. The progresses on stabilising the ecosystem are tracked on the opam readiness for 5.3.0 meta-issue.
Meanwhile, the second beta release of OCaml 5.3.0 is here to help you update your software and libraries ahead of the release (see below for the installation instructions).
The full release is expected before the end of December.
If you find any bugs, please report them on OCaml's issue tracker.
If you are interested in full list of features and bug fixes of the new OCaml version, the updated change log for OCaml 5.3.0 is available on GitHub.
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 5.3.0~beta2
The source code for the beta is also available at these addresses:
Fine-Tuned Compiler Configuration
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.5.3.0~beta2+options <option_list>
where option_list is a space separated list of ocaml-option-* packages. For instance, for a flambda and no-flat-float-array switch:
opam switch create 5.3.0~beta2+flambda+nffa ocaml-variants.5.3.0~beta2+options ocaml-option-flambda ocaml-option-no-flat-float-array
All available options can be listed with opam search ocaml-option.
See full changelog
Changes Since The First Beta
Type system fixes
-
#13501: Regression on mutually recursive types caused by #12180. Resuscitate Typedecl.update_type. (Jacques Garrigue and Takafumi Saikawa, review by Florian Angeletti, Richard Eisenberg and Gabriel Scherer)
-
#13495, #13514: Fix typechecker crash while typing objects (Jacques Garrigue, report by Nicolás Ojeda Bär, review by Nicolas Ojeda Bär, Gabriel Scherer, Stephen Dolan, Florian Angeletti)
-
#13598: Falsely triggered warning 56 [unreachable-case] This was caused by unproper protection of the retyping function. (Jacques Garrigue, report by Tõivo Leedjärv, review by Florian Angeletti)
Configuration fixes
- (breaking change) #12578, #12589, #13322, +#13519: Use configured CFLAGS and CPPFLAGS only during the build of the compiler itself. Do not use them when compiling third-party C sources through the compiler. Flags for compiling third-party C sources can still be specified at configure time in the COMPILER_{BYTECODE,NATIVE}_{CFLAGS,CPPFLAGS} configuration variables. (Sébastien Hinderer, report by William Hu, review by David Allsopp)
C++ header compatibility
- #13541, #13591: Fix headers for C++ inclusion. (Antonin Décimo, review by Nick Barnes, report by Kate Deplaix)