Evaluate TypeScript 7 (native tsgo compiler) adoption

[mellonis]

Tracking issue for evaluating TypeScript 7 (the native tsgo-based compiler) adoption across this repo. Umbrella for splitting the work into separate PRs, per the probe findings below.

Summary

Probed typescript@7.0.1-rc against this repo's real gates (npm run build, npm run typecheck, npm run lint, npm test) in an isolated worktree. Nothing from the probe landed.

Verdict: not adoptable today. build and typecheck are one config line away from green; lint hard-crashes on a structural incompatibility that is entirely upstream-blocked (typescript-eslint).

What works

• tsc --build (project references + declaration emit) and tsc --noEmit typecheck: both pass cleanly under TS 7.0.1-rc once moduleResolution is changed away from the now-removed "node" (node10) mode. Confirmed with "bundler"; "nodenext"/"node16" may be more appropriate for a published library and should be evaluated as an alternative.
  • dist/ output: file list is byte-identical to the TS 6.0.3 baseline (70 files, same paths). Content is byte-identical for 67/70 files; the other 3 differ only cosmetically (helper-declaration ordering in one .js file; an empty declare namespace id {} correctly dropped from one .d.ts; an accessor pair rendered as get/set instead of collapsed to a plain property in another .d.ts — all non-breaking).
  • Verified this config fix is TS-version-independent: re-tested moduleResolution: "bundler" under the current baseline typescript@6.0.3 — build, typecheck, lint, and test all pass. So this is a standalone hygiene fix, not a TS7-only workaround.
• npm test (Vitest): completely unaffected either way — Vitest uses esbuild for TS transforms, never touches the typescript package. 30 files / 664 tests pass under both TS6 and TS7.

What's blocked

• npm run lint (ESLint 10.4.1 + typescript-eslint 8.60.1) hard-crashes under TS 7.0.1-rc — not a warning, a fatal Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: No "exports" main defined in node_modules/typescript/package.json.
  • Root cause: the typescript npm package at 7.0.1-rc ships no root . export, no main, no types in its package.json — only ./unstable/* entries (./unstable/sync, ./unstable/async, ./unstable/fs, ./unstable/ast*, etc.). Any tool doing the classic require('typescript') (which is what @typescript-eslint/typescript-estree does) fails outright at the Node module-resolution layer.
  • typescript-eslint declares typescript: ">=4.8.4 <6.1.0" as its peer range — checked against the currently-installed 8.60.1, the latest stable (8.62.1), and the latest alpha prerelease (8.62.2-alpha.11) via npm view typescript-eslint@<version> peerDependencies. All three declare the identical range. TS 7.0.1-rc is outside all of them, with no visible movement toward support as of this check. (Notably, typescript-eslint's own devDependencies already include @typescript/native-preview — they're dogfooding tsgo internally — but that hasn't produced a widened peer range yet.)
  • No repo-side workaround exists; this is 100% an upstream blocker.

CLI / packaging story

Installing the typescript package itself at 7.0.1-rc (not the standalone @typescript/native-preview package) makes npx tsc --version report 7.0.1-rc directly — tsc itself becomes the native compiler, no separate tsgo binary is present or needed. bin/tsc is a thin JS shim that execs a platform-specific native binary from an optionalDependencies package (confirmed as a genuine Mach-O arm64 executable on this machine). Per the package's own README: "For TypeScript 7.0 RC and later, use tsc just like for TypeScript 6.0. For other builds, use the tsgo command."

Recommended plan — split into separate PRs

• PR 1 — config hygiene (landable now, under current TS 6.0.3): replace the removed moduleResolution: "node" setting in the root tsconfig.json with a supported mode ("bundler" confirmed working; evaluate "nodenext"/"node16" as the more library-faithful option). Drop the now-moot "ignoreDeprecations": "6.0" line once node10 is no longer referenced. Zero functional risk — verified green across build/typecheck/lint/test under TS 6.0.3.
• PR 2 — typescript@7.x bump (blocked): gated on typescript-eslint publishing a TS7-compatible peer-dependency range. Do not bump CI's typescript install until then — bumping now would break the lint job. Track typescript-eslint's release notes / peer range for movement.
• Cross-repo note: post-machine-js and machines-demo run the same ESLint + typescript-eslint + tsc toolchain and would hit the identical lint crash on a TS7 bump. The real gate is the single upstream typescript-eslint dependency shared by all three repos in this workspace — one unblock clears all three.

Full probe log

Preserved in the probe worktree at .superpowers-ts7-probe.md (not committed — experiment-only, per the task that produced it). Reproducing the key data points above is straightforward: npm install -D typescript@7.0.1-rc, then run the repo's four standard gates.