Fix arity of generated switcher continuations

[dhil]

This patch fixes a bug with the arity of the continuation reference
generated by a switch (aka the current continuation). Its arity was
mistakenly derived from the switch-tag's codomain. The arity of the
current continuation can be obtained at the switch point by
deconstructing the type annotation on it.

Fixes #103.

[rossberg]

Oops, sorry, had missed this!

[dhil]

There seems to be some problem with the CI -- is this fixed upstream?

[rossberg]

Btw, can you do a PR to rename Handle to Prompt?

[dhil]

Btw, can you do a PR to rename Handle to Prompt?

Yes, absolutely. Maybe better if I do that in a separate PR? Regardless, the CI fails to install OCaml -- is this a known issue elsewhere? Do we need to update the workflow definition?

[rossberg]

Yes, separate PR.

The CI issue probably is just a glitch. Those happen, just manually restart the workflow.

[dhil]

Yes, separate PR.

The CI issue probably is just a glitch. Those happen, just manually restart the workflow.

I've restarted it multiple times already. Actually, it seems like the CI cannot install darcs:

  /usr/bin/sudo apt-get --yes install bubblewrap darcs g++-multilib gcc-multilib mercurial musl-tools rsync
  Reading package lists...
  Building dependency tree...
  Reading state information...
  Package darcs is not available, but is referred to by another package.
  This may mean that the package is missing, has been obsoleted, or
  is only available from another source
  E: Package 'darcs' has no installation candidate
  Notice: An error has been caught in some system package index files, so the system package index files have been re-synchronised, and the system package installation has been retried: the process '/usr/bin/sudo' failed with exit code 100
  /usr/bin/sudo apt-get update
  Get:1 file:/etc/apt/apt-mirrors.txt Mirrorlist [142 B]
  Hit:2 http://azure.archive.ubuntu.com/ubuntu noble InRelease
  Hit:6 https://packages.microsoft.com/repos/azure-cli noble InRelease
  Hit:7 https://packages.microsoft.com/ubuntu/24.04/prod noble InRelease
  Get:3 http://azure.archive.ubuntu.com/ubuntu noble-updates InRelease [126 kB]
  Hit:4 http://azure.archive.ubuntu.com/ubuntu noble-backports InRelease
  Hit:5 http://azure.archive.ubuntu.com/ubuntu noble-security InRelease
  Fetched 126 kB in 1s (241 kB/s)
  Reading package lists...
  /usr/bin/sudo apt-get --yes install bubblewrap darcs g++-multilib gcc-multilib mercurial musl-tools rsync
  Reading package lists...
  Building dependency tree...
  Reading state information...
  Package darcs is not available, but is referred to by another package.
  This may mean that the package is missing, has been obsoleted, or
  is only available from another source
  E: Package 'darcs' has no installation candidate
Error: The process '/usr/bin/sudo' failed with exit code 100

[dhil]

I think what has happened is that the version of ubuntu-latest has been bumped. Consequently, the package repositories have been changed too.

Edit: I think my analysis is correct, see ocaml/setup-ocaml#872

[dhil]

@rossberg I think we need to update the workflow to use setup-ocaml@v3 (which supposedly fixes the problem). Probably every active repo requires this change.

[rossberg]

IIRC, I already upgraded upstream last year. Maybe it'd be good to resync this one soon.

[dhil]

IIRC, I already upgraded upstream last year. Maybe it'd be good to resync this one soon.

Yes. Should I merge with WebAssembly/spec main or branch wasm-3.0? The latter seems to have been updated last time in November.

[rossberg]

wasm-3.0, since that's the baseline here, isn't it? Only that has references and exceptions and all.

[dhil]

wasm-3.0, since that's the baseline here, isn't it? Only that has references and exceptions and all.

OK. I will do two more PRs. One for renaming Handle to Prompt and one to sync with wasm-3.0.