compiler: update typecore; tests: add VariantCoercionConstructUsed; d…

[cristianoc]

…ocs: update AGENTS; docstring_tests: update DocTest outputs

[pkg-pr-new[bot]]

Open in StackBlitz

rescript

npm i https://pkg.pr.new/rescript-lang/rescript@7839

@rescript/darwin-arm64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/darwin-arm64@7839

@rescript/darwin-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/darwin-x64@7839

@rescript/linux-arm64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/linux-arm64@7839

@rescript/linux-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/linux-x64@7839

@rescript/runtime

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/runtime@7839

@rescript/win32-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/win32-x64@7839

commit: 6012c86

[zth]

The example is wrong, it does not trigger the warning. Update the example to be:

// Repro for incorrect "constructor ... is never used" warning with coercions
// This should compile cleanly without warnings when coercing from a -> b.

type a = A | B
module DoNotWarn: {
  let log: a => unit
} = {
  type b =
    | ...a
    | C

  let log = (x: a) => Js.log((x :> b))
}

let _ = DoNotWarn.log(A)

[cristianoc]

The example is wrong, it does not trigger the warning. Update the example to be:

// Repro for incorrect "constructor ... is never used" warning with coercions
// This should compile cleanly without warnings when coercing from a -> b.

type a = A | B
module DoNotWarn: {
  let log: a => unit
} = {
  type b =
    | ...a
    | C

  let log = (x: a) => Js.log((x :> b))
}

let _ = DoNotWarn.log(A)

Took it from the chat. Let me close this and start again.

[zth]

@jfrolich can you verify whether the test added to this branch gives the expected warning (warns about 1 constructor)?

[jfrolich]

Yes it should warn about C, but not about the other constructors!

[zth]

Great! So @cristianoc it seems the implementation is correct. I think we can move ahead with cleanup.

[cristianoc]

Great! So @cristianoc it seems the implementation is correct. I think we can move ahead with cleanup.

Any more cases to test? With interfaces? If not, then cleanup.

[zth]

Great! So @cristianoc it seems the implementation is correct. I think we can move ahead with cleanup.

Any more cases to test? With interfaces? If not, then cleanup.

It only triggers for things with interfaces. I guess for completeness sake we could add an example where the new type is just a spread of the other type, with no new constructors added (but still using coercion), to see that all constructors are marked as being used.

[cristianoc]

@zth take another look

[zth]

@cristianoc added a few comments. The changelog text is quite convoluted as well, but I'm not sure I care too much about that.

[cristianoc]

@zth would you take over the PR? Getting diminishing returns going back and forth for little things later, we can "create an environment for this repo."

[zth]

Let's close it if so, and someone can use the insights here as the base for fixing this later on.

[cristianoc]

Let's close it if so, and someone can use the insights here as the base for fixing this later on.

hold on, our assistant is thinking

[cristianoc]

@codex try to build the compiler and run tests now, report if it worked

[chatgpt-codex-connector[bot]]

Summary

• Build failed: make terminated while compiling the Rust-based rewatch component, preventing the subsequent dune build step from running
• Build environment missing dune; direct invocation shows bash: command not found: dune
• Test suite did not run: make test similarly terminated during the rewatch build phase

Testing

• ❌ make (terminated during rewatch build; could not reach compiler build step)
• ❌ dune build (dune not installed)
• ❌ make test (terminated during rewatch build; tests not executed)

View task →

[cristianoc]

@codex try again to build the compiler now that internet access is enabled in the sandbox

[chatgpt-codex-connector[bot]]

Summary

• Bootstrapped and installed Dune 3.17 to satisfy the repository’s required Dune language version.
• make still failed because opam packages such as flow_parser, yojson, ounit2, cmarkit, and the tool cppo were missing from the environment
• make test likewise failed for the same missing dependencies, so the test suite could not run

Testing

• ❌ make
• ❌ make test

Notes

• Access to opam repositories is blocked (HTTP 403), preventing installation of the required OCaml packages and tools.

View task →

[cristianoc]

CODEX: I reviewed the latest change to mark shared constructors as used after variant→variant coercions. Verified there’s no redundancy in typecore and no leftover duplication; the extra exposed-decl marking was removed and inclusion handles propagation. Tests cover no spurious warning and still warn for target-only constructors. CHANGELOG updated.

@zth Anything else to address here? If not, we’re good to merge. Thanks!