Add TypeScript 7 support to dtslint

[Jake Bailey (jakebailey)]

It turns out that we have enough API in 7.0 and 7.1 to be able to do $ExpectType and diagnostics. So, do that!

[Copilot]

Pull request overview

Adds TypeScript 7.0/7.1 support to dtslint through TypeScript’s out-of-process API.

Changes:

• Registers TypeScript 7 packages and version metadata.
• Adds TypeScript 7 diagnostics, $ExpectType, ESLint, and local-build handling.
• Upgrades bundled TypeScript and TypeScript ESLint dependencies.

Reviewed changes

Copilot reviewed 29 out of 34 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pnpm-lock.yaml	Locks upgraded tooling and TypeScript 7 packages.
packages/typescript-versions/test/index.test.ts	Tests new version ranges and tags.
packages/typescript-versions/src/index.ts	Registers TypeScript 7.0 and 7.1.
packages/typescript-packages/test/index.test.ts	Tests TypeScript 7 API subpaths.
packages/typescript-packages/src/index.ts	Supports resolving package subpaths.
packages/typescript-packages/package.json	Adds TypeScript 7 aliases.
packages/publisher/package.json	Upgrades TypeScript to 6.0.
packages/mergebot/package.json	Upgrades TypeScript to 6.0.
packages/eslint-plugin/test/__file_snapshots__/types/expect-tsconfigs/index.d.ts.lint	Updates TypeScript 6 diagnostics snapshot.
packages/eslint-plugin/test/__file_snapshots__/types/expect-tsconfigs/expect-dom-tests.ts.lint	Updates TypeScript 6 lint snapshot.
packages/eslint-plugin/package.json	Upgrades TypeScript ESLint and TypeScript.
packages/dtslint/test/typescript7-eslint/tsconfig.json	Configures TypeScript 7 ESLint fixture.
packages/dtslint/test/typescript7-eslint/test.cts	Adds ordinary ESLint failures fixture.
packages/dtslint/test/typescript7-eslint/index.d.ts	Adds fixture declaration entrypoint.
packages/dtslint/test/typescript7-eslint/.eslintrc.json	Configures fixture ESLint rules.
packages/dtslint/test/tsconfig.json	Excludes standalone fixtures.
packages/dtslint/test/index.test.ts	Tests TypeScript 7 lint paths.
packages/dtslint/test/fixtures/typescript7/pass/tsconfig.json	Configures passing fixture.
packages/dtslint/test/fixtures/typescript7/pass/test.ts	Exercises successful assertions and ranges.
packages/dtslint/test/fixtures/typescript7/pass/index.d.ts	Defines passing fixture API.
packages/dtslint/test/fixtures/typescript7/fail/tsconfig.json	Configures failing fixture.
packages/dtslint/test/fixtures/typescript7/fail/test.ts	Exercises diagnostics and assertion failures.
packages/dtslint/test/fixtures/typescript7/fail/index.d.ts	Defines failing fixture API.
packages/dtslint/test/fixtures/typescript7/external/index.d.ts	Tests external diagnostic suppression.
packages/dtslint/src/lintTypeScript7.ts	Implements TypeScript 7 IPC linting.
packages/dtslint/src/lint.ts	Routes versions between legacy and IPC linting.
packages/dtslint/src/index.ts	Passes tsconfigs and validates CLI options.
packages/dtslint/package.json	Updates runtime compiler dependencies.
packages/dts-gen/package.json	Upgrades TypeScript to 6.0.
packages/dts-critic/package.json	Upgrades TypeScript to 6.0.
packages/definitions-parser/package.json	Upgrades development TypeScript.
package.json	Upgrades repository TypeScript tooling.
.changeset/tidy-tigers-compile.md	Records TypeScript 6 upgrades.
.changeset/strong-dragons-check.md	Records TypeScript 7 support.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

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[Copilot]

Pull request overview

Copilot reviewed 30 out of 35 changed files in this pull request and generated no new comments.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

Suppressed comments (2)

packages/dtslint/test/index.test.ts:242

• This walks one directory too far. Since apiPath ends in typescript/api/sync/api.js, four .. segments resolve to the containing node_modules, and the subsequent path.dirname(packageRoot) builds an @typescript/... path outside that directory. The local-server test therefore passes a nonexistent executable to lint. Stop at the TypeScript package root instead.

          const packageRoot = path.resolve(apiPath, "../../../../");

packages/dtslint/src/lintTypeScript7.ts:125

• For local TypeScript 7 runs this passes the literal version "local" into semver.satisfies below. That value cannot satisfy any version range, so every TS2578 diagnostic is treated as outside its range and suppressed—even an unused // @ts-expect-error >=7.0, which should fail a local TS7 run. Use the resolved client version for range evaluation while keeping local only as the report label.

        addFailures(getDiagnosticFailures(project, dirPath, version, isLatest), run);

[Copilot]

Pull request overview

Copilot reviewed 41 out of 47 changed files in this pull request and generated no new comments.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

Suppressed comments (3)

packages/dtslint/src/lint.ts:240

• Directory-form --localTs paths containing the released TypeScript 7 executable are rejected here because the native package exposes tsc (and this PR’s own local-build test resolves lib/tsc), but this probe only recognizes tsserver/tsgo. Include tsc and tsc.exe so the documented directory-style local installation works for TypeScript 7.

  if (["tsserver", "tsserver.exe", "tsgo", "tsgo.exe"].some((name) => fs.existsSync(joinPaths(tsLocal, name)))) {

packages/dtslint/src/lintTypeScript7.ts:179

• Even after local-build detection accepts a directory containing TypeScript 7’s standard tsc executable, this lookup still cannot select it. Add tsc/tsc.exe; otherwise callers must pass the executable itself rather than the supported directory form.

  for (const name of ["tsserver", "tsserver.exe", "tsgo", "tsgo.exe"]) {

packages/utils/src/expect-error-range.ts:5

• The multiline-comment matcher captures the closing */ as part of the range. For example, /* @ts-expect-error <7.0 */ yields <7.0 */, validRange rejects it, and TS2578 is reported even when the current version is outside the range. Strip the closing delimiter in the matcher and add a block-comment regression case.

[Copilot]

Pull request overview

Copilot reviewed 43 out of 49 changed files in this pull request and generated no new comments.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file

[Jake Bailey (jakebailey)]

One tweak I need to make is to not call this "typescript 7"

[Jake Bailey (jakebailey)]

Going to hold off on this until TS 7.1 has parseSourceFile, then I will just use 6.0+7.0 together, with 7.1+ being Strada API free.

[Andrew Branch (andrewbranch)]

Do we really need to support previous nightlies?

[Jake Bailey (jakebailey)]

This is for 7.0 support, not specifically old nightlies. I feel wary not supporting 7.0 at all given 7.1 has type related changes in it.

[Andrew Branch (andrewbranch)]

Hm, but theoretically being 6.0 type-compatible is being 7.0 type-compatible, right? I feel like it takes a lot of workarounds to make this work with the 7.0 unstable API, but I guess it's not a ton of code.

[Jake Bailey (jakebailey)]

Sadly, there are quite a few real differences that 7.0 already showed: DefinitelyTyped/DefinitelyTyped#75408

There's error positioning, which could be worked around, but there's also problems with es5 removal, strict binding, etc, which 6.0 still avoids.

I could imagine skipping 7.0 but then we'd have a hard time understanding how to typesVersions it.

[Jake Bailey (jakebailey)]

I updated the PR so that 7.1 is not run unless we're doing a local build, that way API changes we're making can be handled on the fly and not require people to update locally. This at least gets us 7.0 on DT and typesVersions.

[Jake Bailey (jakebailey)]

Going to merge but not release this yet, and make sure run dt works.