fix(noInvalidUseBeforeDeclaration): don't report use before ambient var declaration #8104

Conaclos · 2025-11-14T19:20:31Z

Summary

This is a small fix of an issue I met on a personal project.
Basically noInvalidUseBeforeDeclaration reported the following code as invalid:

c;
declare const c: number

While it is valid because c is an ambient variable that is hoisted.

Test Plan

I added a test.

Docs

I added a changeset.

changeset-bot · 2025-11-14T19:20:36Z

🦋 Changeset detected

Latest commit: cbd209d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@biomejs/biome	Patch
@biomejs/cli-win32-x64	Patch
@biomejs/cli-win32-arm64	Patch
@biomejs/cli-darwin-x64	Patch
@biomejs/cli-darwin-arm64	Patch
@biomejs/cli-linux-x64	Patch
@biomejs/cli-linux-arm64	Patch
@biomejs/cli-linux-x64-musl	Patch
@biomejs/cli-linux-arm64-musl	Patch
@biomejs/wasm-web	Patch
@biomejs/wasm-bundler	Patch
@biomejs/wasm-nodejs	Patch
@biomejs/backend-jsonrpc	Patch

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coderabbitai · 2025-11-14T19:23:44Z

Walkthrough

The PR updates the noInvalidUseBeforeDeclaration lint: it skips TypeScript declaration files by checking JsFileSource::is_definition_file and treats ambient declare variable declarations as non-violations by adjusting DeclarationKind::try_from (including special-case handling for object shorthand and ambient TS_DECLARE_STATEMENT). A test was added that uses c; before declare const c: number;. No public API signatures changed.

Suggested reviewers

ematipico
dyc3

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run `@coderabbitai generate docstrings` to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main fix: preventing the noInvalidUseBeforeDeclaration rule from reporting uses before ambient variable declarations.
Description check	✅ Passed	The description is directly related to the changeset, explaining the issue with ambient variables, providing a concrete example, and noting test coverage and documentation additions.

✨ Finishing touches

📝 Generate docstrings

🧪 Generate unit tests (beta)

Create PR with unit tests
Post copyable unit tests in a comment
Commit unit tests in branch conaclos/noInvalidUseBeforeDeclaration-ambient-variables

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…ar declaration

codspeed-hq · 2025-11-14T19:37:09Z

CodSpeed Performance Report

Merging #8104 will not alter performance

_{Comparing conaclos/noInvalidUseBeforeDeclaration-ambient-variables (cbd209d) with main (82b9a8e)}

Summary

✅ 58 untouched
⏩ 95 skipped¹

95 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. ↩

coderabbitai

Actionable comments posted: 0

🧹 Nitpick comments (1)

crates/biome_js_analyze/src/lint/correctness/no_invalid_use_before_declaration.rs (1)
223-225: Optional: Simplify by adding to the pattern list above.

The block wrapper is unnecessary—you could just append this variant to the | pattern chain at lines 219–222.

Apply this diff to simplify:
 AnyJsBindingDeclaration::JsArrayBindingPatternElement(_)
 | AnyJsBindingDeclaration::JsArrayBindingPatternRestElement(_)
 | AnyJsBindingDeclaration::JsObjectBindingPatternProperty(_)
 | AnyJsBindingDeclaration::JsObjectBindingPatternRest(_)
-| AnyJsBindingDeclaration::JsObjectBindingPatternShorthandProperty(_) => {
-    Ok(Self::Variable)
-}
+| AnyJsBindingDeclaration::JsObjectBindingPatternShorthandProperty(_)
-AnyJsBindingDeclaration::JsVariableDeclarator(declarator) => {
+| AnyJsBindingDeclaration::JsVariableDeclarator(declarator) => {
     if let Some(var_decl) = declarator.declaration()

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📥 Commits

Reviewing files that changed from the base of the PR and between fe1f34b and cbd209d.

📒 Files selected for processing (1)

crates/biome_js_analyze/src/lint/correctness/no_invalid_use_before_declaration.rs (3 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (13)

GitHub Check: Bench (biome_js_analyze)
GitHub Check: Bench (biome_js_formatter)
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GitHub Check: Check Dependencies
GitHub Check: Lint project (depot-windows-2022)
GitHub Check: Lint project (depot-ubuntu-24.04-arm-16)
GitHub Check: Test (depot-windows-2022-16)
GitHub Check: Documentation
GitHub Check: Test (depot-ubuntu-24.04-arm-16)
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GitHub Check: Test Node.js API

🔇 Additional comments (3)

crates/biome_js_analyze/src/lint/correctness/no_invalid_use_before_declaration.rs (3)

6-7: LGTM! Required imports for the fix.

The new imports support the declaration file check and ambient declaration detection.

85-91: Good optimisation! Skipping declaration files entirely.

Declaration files (.d.ts) only contain ambient declarations, so this early exit is both correct and efficient.

226-237: Excellent fix! Ambient declarations are now correctly excluded.

The parent-chain check properly identifies declare variables, which are hoisted and can be used before their declaration point. Returning Err(()) ensures they skip validation at line 105.

…ar declaration (biomejs#8104)

github-actions bot added A-Linter Area: linter L-JavaScript Language: JavaScript and super languages labels Nov 14, 2025

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Conaclos force-pushed the conaclos/noInvalidUseBeforeDeclaration-ambient-variables branch from 6f3c4c2 to fe1f34b Compare November 14, 2025 19:25

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fix(noInvalidUseBeforeDeclaration): don't report use before ambient v…

fe1f34b

…ar declaration

coderabbitai bot reviewed Nov 14, 2025

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refactor: more robust check

cbd209d

dyc3 approved these changes Nov 14, 2025

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ematipico approved these changes Nov 15, 2025

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ematipico merged commit 041196b into main Nov 15, 2025
18 checks passed

ematipico deleted the conaclos/noInvalidUseBeforeDeclaration-ambient-variables branch November 15, 2025 08:42

github-actions bot mentioned this pull request Nov 15, 2025

ci: release #8076

Merged

This was referenced Nov 15, 2025

fix(noInvalidUseBeforeDeclaration): handle class, enum, import-equals #8113

Merged

fix(noInvalidUseBeforeDeclaration): ignore valid use before declarations #8157

Merged

ematipico pushed a commit to hamirmahal/biome that referenced this pull request Nov 19, 2025

fix(noInvalidUseBeforeDeclaration): don't report use before ambient v…

084c1dd

…ar declaration (biomejs#8104)

l0ngvh pushed a commit to l0ngvh/biome that referenced this pull request Dec 21, 2025

fix(noInvalidUseBeforeDeclaration): don't report use before ambient v…

ff7d311

…ar declaration (biomejs#8104)

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fix(noInvalidUseBeforeDeclaration): don't report use before ambient var declaration #8104

fix(noInvalidUseBeforeDeclaration): don't report use before ambient var declaration #8104

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fix(noInvalidUseBeforeDeclaration): don't report use before ambient var declaration #8104

fix(noInvalidUseBeforeDeclaration): don't report use before ambient var declaration #8104

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Conaclos commented Nov 14, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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CodSpeed Performance Report

Merging #8104 will not alter performance

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Conaclos commented Nov 14, 2025 •

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