pstack statechart: strict typecheck reports four errors in run.ts and CLI tests #1141

Summary

The statechart compiler in pstack 0.15.36 produces four TypeScript errors when checked with its existing scripts/tsconfig.json. I reproduced this on an unchanged copy of commit c742dd61706fbacc1b95f1a20b7b988cf096ce6c, using the pinned toolchain below.

There are two causes, each reported at two locations:

• run.ts: the exit property in common is inferred as number, while CheckResult.exit requires 0 | 1 | 2. Both returns that spread common fail.
• test/cli.test.ts: two test callbacks return signalWhile(...), whose promise resolves to the phase object. The Node TestFn type requires void | Promise<void>.

Reproduce

git clone --filter=blob:none --sparse https://github.com/cursor/plugins.git pstack-typecheck-repro
cd pstack-typecheck-repro
git sparse-checkout set pstack
git checkout --detach c742dd61706fbacc1b95f1a20b7b988cf096ce6c
cd pstack/skills/statechart/scripts

npm install --ignore-scripts --no-save --package-lock=false --no-audit --no-fund typescript@7.0.2 @types/node@26.1.2
./node_modules/.bin/tsc -p tsconfig.json --pretty false

No changes to source files or tsconfig.json are needed. The package's declared fast-check@4.5.3 dependency is installed along with the two explicit packages.

Environment used:

• macOS, arm64
• Node 24.13.0, npm 11.6.2
• TypeScript 7.0.2, @types/node 26.1.2, fast-check 4.5.3

Actual result

The command exits 1 with these diagnostics, abbreviated:

run.ts(455,9): error TS2322: ... is not assignable to type 'CheckResult'.
  Types of property 'exit' are incompatible.
    Type 'number' is not assignable to type '0 | 1 | 2'.

run.ts(471,5): error TS2322: ... is not assignable to type 'CheckResult'.
  Types of property 'exit' are incompatible.
    Type 'number' is not assignable to type '0 | 1 | 2'.

test/cli.test.ts(430,5): error TS2345: ... is not assignable to parameter of type 'TestFn'.
  Type 'Promise<...phase object...>' is not assignable to type 'void | Promise<void>'.

test/cli.test.ts(453,5): error TS2345: ... is not assignable to parameter of type 'TestFn'.
  Type 'Promise<...phase object...>' is not assignable to type 'void | Promise<void>'.

Expected result and scope

Checking the existing strict TypeScript configuration should exit 0, or the supported compiler and Node type versions should be specified if a different toolchain is intended.

The package currently exposes a runtime test command rather than a typecheck command. I did not observe a CLI failure caused by these type errors: a passing-model smoke test exited 0, and a counterexample smoke test exited 1 with the expected report. This report concerns static checking with the versions above.

A contextual type for common that preserves CheckResult["exit"], and callbacks that await signalWhile without returning its phase object, appear to be the relevant correction points.