feat(semantic): add TS2670 error for global scope augmentation without declare modifier

[camc314]

Report error when global { } is used without declare modifier and not in an already ambient context (like .d.ts files or inside declare module blocks).

Discovered while working on #16743

🤖 generated with help from Claude Opus 4.5

[camc314]

• fix(semantic): add TS error code 1235 to namespace declaration diagnostic #16747
• feat(semantic): add TS2670 error for global scope augmentation without declare modifier #16746 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

This PR adds semantic checking for TypeScript's TS(2670) error, which requires global scope augmentations to have the declare modifier unless they're already in an ambient context (like .d.ts files or inside declare module blocks). The check prevents incorrect usage of global { } blocks without the proper declare keyword.

Key Changes

• Adds new TypeScript semantic check for global scope augmentations requiring declare modifier
• Updates test coverage snapshot showing one additional negative test case now passing (moduleAugmentationGlobal6_1.ts)

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_semantic/src/checker/typescript.rs	Implements the TS(2670) diagnostic check by adding validation logic to check_ts_global_declaration
tasks/coverage/snapshots/parser_typescript.snap	Updates test coverage metrics and removes moduleAugmentationGlobal6_1.ts from expected failures, showing the error is now properly detected

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[codspeed-hq]

CodSpeed Performance Report

Merging #16746 will not alter performance

_{Comparing c/12-11-feat_semantic_add_ts_2670_error_for_global_scope_augmentation_without_declare_modifier (e177d94) with main (3ffe342)¹}

Summary

✅ 42 untouched
⏩ 3 skipped²

Footnotes

1. No successful run was found on main (6432aff) during the generation of this report, so 3ffe342 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[graphite-app]

Merge activity

• Dec 11, 1:27 PM UTC: Boshen added this pull request to the Graphite merge queue.
• Dec 11, 1:34 PM UTC: Merged by the Graphite merge queue.