Upgrade to tsgo (TypeScript 7)

Context

TypeScript 7 (tsgo) — the Go-based native rewrite of tsc — is targeting early 2026 release. It provides ~10x faster type-checking and an improved language service.

The Effect ecosystem is also preparing a tsgo-based Effect Language Service: https://github.com/mattiamanzati/effect-typescript-go (may not yet be publicly available).

Motivation

• Significantly faster dt ts:check and dt ts:build (10x reported improvement)
• Native --build mode support landed in tsgo (Nov 2025, microsoft/typescript-go#529)
• The current ts:check uses tsc -p --noEmit which doesn't enforce project-reference isolation (see #222). Switching to --build --noEmit is blocked by TS#53979. tsgo may resolve this
• New tsgo-based Effect Language Service will provide better IDE integration

Getting Started (Darwin)

pnpx https://pkg.pr.new/mattiamanzati/effect-typescript-go/@effect/language-service-tsgo@767ad30

Patch in the same folder you have dependency on @typescript/native-preview (usually project root).

To enable in editor (VSCode-based), add to settings.json:

"typescript.native-preview.tsdk": "node_modules/@typescript/native-preview"

Tasks

• Track tsgo stable release (TypeScript 7.0)
• Evaluate tsgo compatibility with this repo's project-references setup
• Test tsgo --build --noEmit — verify whether the TS6310 limitation (--build --noEmit with project refs) is resolved
• Update Nix packaging to use tsgo binary
• Update ts:check / ts:build tasks in nix/devenv-modules/tasks/shared/ts.nix
• Migrate to tsgo-based Effect Language Service (mattiamanzati/effect-typescript-go) once available
• Update @effect/language-service plugin config if needed
• Verify CI pipeline works end-to-end with tsgo

Related

• #222 — attempted --build --noEmit fix (blocked by TS6310)
• microsoft/typescript-go
• Effect-TS/language-service
• mattiamanzati/effect-typescript-go

Created by an AI assistant on behalf of @schickling

Start by reading nix/devenv-modules/tasks/shared/ts.nix and reviewing related issue #222. Evaluate tsgo project-reference support with tsgo --build --noEmit, then check the Nix packaging, ts:check and ts:build tasks, language-service configuration, and CI. Done means the repository and CI work end-to-end with the supported tsgo setup.