feat(biome_js_analyze): implement noReturnAssign rule #8248
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🦋 Changeset detectedLatest commit: 28cf924 The changes in this PR will be included in the next version bump. This PR includes changesets to release 13 packages
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WalkthroughAdds a new lint rule Suggested reviewers
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🧹 Nitpick comments (3)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
48-48: Consider usingSeverity::Warninginstead.Per the project guidelines,
Severity::Errorshould be reserved for hard errors, dangerous code, or accessibility issues. This rule catches potentially confusing but not inherently dangerous patterns. ESLint also treats this as a warning by default.- severity: Severity::Error, + severity: Severity::Warning,
65-83: Consider highlighting the specific assignment expression in the diagnostic.Currently, the diagnostic highlights the entire return statement. For clarity, it might be more helpful to highlight just the assignment expression within the return. This would require adjusting the
Statetype to capture the assignment node's range.crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js (1)
1-16: Add arrow function test cases to verify rule scope.The rule implementation queries only
JsReturnStatement, so arrow functions with implicit returns (e.g.,const f = (a) => a = 1;) wouldn't be caught. Adding tests likeconst f = (a) => a = 1;andconst f = (a) => (a = 1);toinvalid.jsandvalid.jswould clarify whether this is intentional or a gap.
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⛔ Files ignored due to path filters (7)
crates/biome_configuration/src/analyzer/linter/rules.rsis excluded by!**/rules.rsand included by**crates/biome_diagnostics_categories/src/categories.rsis excluded by!**/categories.rsand included by**crates/biome_js_analyze/src/lint/nursery.rsis excluded by!**/nursery.rsand included by**crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js.snapis excluded by!**/*.snapand included by**crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js.snapis excluded by!**/*.snapand included by**packages/@biomejs/backend-jsonrpc/src/workspace.tsis excluded by!**/backend-jsonrpc/src/workspace.tsand included by**packages/@biomejs/biome/configuration_schema.jsonis excluded by!**/configuration_schema.jsonand included by**
📒 Files selected for processing (5)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js(1 hunks)crates/biome_rule_options/src/lib.rs(1 hunks)crates/biome_rule_options/src/no_return_assign.rs(1 hunks)
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**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
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Files:
crates/biome_rule_options/src/lib.rscrates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
🧠 Learnings (28)
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report undefined entities should use the 'noUndeclared<Concept>' naming convention (e.g., `noUndeclaredVariables`)
Applied to files:
crates/biome_rule_options/src/lib.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that overwhelmingly apply to a specific framework should be named using 'use<Framework>...' or 'no<Framework>...' prefix (e.g., `noVueReservedProps`)
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report redundant code should use the 'noRedundant<Concept>' naming convention (e.g., `noRedundantUseStrict`)
Applied to files:
crates/biome_rule_options/src/lib.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that allow users to ban specific entities should use the 'noRestricted<Concept>' naming convention (e.g., `noRestrictedGlobals`)
Applied to files:
crates/biome_rule_options/src/lib.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report unused entities should use the 'noUnused<Concept>' naming convention (e.g., `noUnusedVariables`)
Applied to files:
crates/biome_rule_options/src/lib.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule options must be defined in the `biome_rule_options` crate in a file matching the rule name (e.g., 'use_this_convention.rs' for rule `useThisConvention`)
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_rule_options/src/lib.rscrates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule implementation should use 'Type Query = Ast<NodeType>' to query the AST/CST for specific node types
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'let else' pattern to reduce code branching when the rule's run function returns 'Vec'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should only have severity set to 'error' if they report hard errors, dangerous code, or accessibility issues; use 'warn' for possibly erroneous code; use 'info' for stylistic suggestions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/tests/specs/**/*.{js,ts,tsx,jsx,json,css,graphql} : Test files should use 'invalid' or 'valid' prefixes to indicate whether they contain code reported by the rule
Applied to files:
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.jscrates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/tests/specs/**/*.{js,ts,tsx,jsx,json,css,graphql} : Test files for rules should be placed inside 'tests/specs/' directory organized by group and rule name (e.g., 'tests/specs/nursery/myRuleName/')
Applied to files:
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.jscrates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option fields should be wrapped in 'Option<_>' to properly track set and unset options during configuration merging
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option structs must derive 'Deserializable', 'Serialize', 'Deserialize', and optionally 'JsonSchema' traits with serde attributes
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : The rule option serde configuration must include 'deny_unknown_fields' to raise errors for extraneous fields in configuration
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : The rule option serde configuration must include 'rename_all = "camelCase"' to match biome.json naming conventions
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option structs must implement the 'biome_deserialize::Merge' trait to handle merging shared and user configurations
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that check computations always evaluated to the same value should use the 'noConstant<Concept>' naming convention (e.g., `noConstantMathMinMaxClamp`)
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
🧬 Code graph analysis (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
crates/biome_analyze/src/rule.rs (3)
sources(617-620)same(246-251)recommended(602-605)crates/biome_rule_options/src/no_return_assign.rs (1)
except_parenthesis(16-19)
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🔇 Additional comments (2)
crates/biome_rule_options/src/lib.rs (1)
172-172: LGTM!The new module is correctly added in alphabetical order.
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js (1)
1-20: LGTM!Good coverage of valid scenarios distinguishing comparisons from assignments.
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🧹 Nitpick comments (2)
.changeset/slick-masks-wear.md (2)
10-10: Minor wording correction: "side effect" should be two words (open compound).Change "side-effect free" to "side effect free" for style consistency.
6-12: Consider making Biome's behaviour more explicit in the description.The description reads more as rationale for the rule rather than a clear statement of what Biome now does. Consider rephrasing to be more user-facing, e.g. "Biome now enforces the ESLint rule
no-return-assign, disallowing assignment expressions inside return statements." This makes it immediately clear what the user should expect.As per coding guidelines, changeset descriptions should use present tense for Biome behaviour (e.g., 'Biome now supports...').
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**/.changeset/*.md
📄 CodeRabbit inference engine (CONTRIBUTING.md)
Changeset descriptions should be user-facing, use past tense for actions taken (e.g., 'Added new feature'), and present tense for Biome behavior (e.g., 'Biome now supports...'). Include issue links, rule links, and code examples where applicable.
Files:
.changeset/slick-masks-wear.md
🧠 Learnings (2)
📚 Learning: 2025-11-24T18:03:52.014Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:03:52.014Z
Learning: For bugfix/feature PRs visible to Biome toolchain users or affecting published crates, create a changeset using the `just new-changeset` command with appropriate package selection, change type (major/minor/patch), and description.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-08-05T14:43:29.581Z
Learnt from: dyc3
Repo: biomejs/biome PR: 7081
File: packages/@biomejs/biome/configuration_schema.json:7765-7781
Timestamp: 2025-08-05T14:43:29.581Z
Learning: The file `packages/biomejs/biome/configuration_schema.json` is auto-generated and should not be manually edited or reviewed for schema issues; any changes should be made at the code generation source.
Applied to files:
.changeset/slick-masks-wear.md
🪛 LanguageTool
.changeset/slick-masks-wear.md
[misspelling] ~10-~10: Did you mean “side effect” (=adverse effect, unintended consequence)? Open compounds are not hyphenated.
Context: ... Return statements are often considered side-effect free. Assignments inside return stateme...
(AFFECT_EFFECT)
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- GitHub Check: Documentation
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- GitHub Check: End-to-end tests
- GitHub Check: Lint project (depot-windows-2022)
- GitHub Check: Check Dependencies
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- GitHub Check: Test Node.js API
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🧹 Nitpick comments (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (1)
86-136: Consider simplifying the return type.The function returns
Option<bool>but never returnsNone—it always returnsSome(true)orSome(false). Returningbooldirectly would be clearer and simpler.Apply this diff:
-fn traverse_expression(root: &AnyJsExpression, except_parenthesis: bool) -> Option<bool> { +fn traverse_expression(root: &AnyJsExpression, except_parenthesis: bool) -> bool { let mut stack = vec![root.clone()]; while let Some(current_node) = stack.pop() { match current_node { - AnyJsExpression::JsAssignmentExpression(_) => return Some(true), + AnyJsExpression::JsAssignmentExpression(_) => return true, // ... rest of match arms ... } } - Some(false) + false }Then update line 62:
-traverse_expression(&query.argument()?, except_parenthesis)?.then_some(()) +traverse_expression(&query.argument()?, except_parenthesis).then_some(())
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crates/biome_cli/src/execute/migrate/eslint_any_rule_to_biome.rsis excluded by!**/migrate/eslint_any_rule_to_biome.rsand included by**crates/biome_configuration/src/analyzer/linter/rules.rsis excluded by!**/rules.rsand included by**packages/@biomejs/backend-jsonrpc/src/workspace.tsis excluded by!**/backend-jsonrpc/src/workspace.tsand included by**packages/@biomejs/biome/configuration_schema.jsonis excluded by!**/configuration_schema.jsonand included by**
📒 Files selected for processing (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs(1 hunks)crates/biome_rule_options/src/no_return_assign.rs(1 hunks)
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**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
Use rustdoc inline documentation for rules, assists, and their options. Create corresponding documentation PRs for other documentation updates against thenextbranch of the website repository.
Set theversionmetadata field in linter rule implementations to'next'for newly created rules. Update this field to the new version number when releasing a minor or major version.
Files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧠 Learnings (14)
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule implementation should use 'Type Query = Ast<NodeType>' to query the AST/CST for specific node types
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'let else' pattern to reduce code branching when the rule's run function returns 'Vec'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report code that can lead to runtime failures should use the 'noUnsafe<Concept>' naming convention (e.g., `noUnsafeOptionalChaining`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧬 Code graph analysis (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (1)
crates/biome_rule_options/src/no_return_assign.rs (1)
except_parenthesis(16-19)
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🔇 Additional comments (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
10-50: LGTM on rule metadata!All fields comply with the guidelines:
versionis set to "next", the ESLint source is properly referenced, and the documentation includes appropriate examples.
52-84: Rule implementation is sound.The
runmethod correctly integrates the option handling and traversal logic, and the diagnostic message clearly explains the issue to users.
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🧹 Nitpick comments (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
93-95: Polish the note formatting.The literal
\nwon't render as line breaks, and the "noReturnAssign:" prefix is redundant since the diagnostic already displays the rule name.Apply this diff:
.note(markup! { - "noReturnAssign: Return statements are often considered side-effect free.\nYou likely want to do a comparison `==`\nOtherwise move the assignment outside of the return statement" + "Return statements are often considered side-effect free. Either use a comparison operator "<Emphasis>"=="</Emphasis>", or move the assignment outside the return statement." }),
100-149: Consider handling unary, await, and yield expressions.Whilst the traversal covers the main cases, assignments nested inside unary operators (
return !(a = 1)), await expressions (return await (a = 1)), or yield expressions would currently be missed. These are fairly rare edge cases, but worth considering for completeness.If you'd like to handle these, you could add:
AnyJsExpression::JsUnaryExpression(expression) => { if let Ok(argument) = expression.argument() { stack.push(argument); } } AnyJsExpression::JsAwaitExpression(expression) => { if let Ok(argument) = expression.argument() { stack.push(argument); } } AnyJsExpression::JsYieldExpression(expression) => { if let Some(Ok(argument)) = expression.argument() { stack.push(argument); } }
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📒 Files selected for processing (5)
.changeset/slick-masks-wear.md(1 hunks)crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/valid.js(1 hunks)crates/biome_rule_options/src/no_return_assign.rs(1 hunks)
✅ Files skipped from review due to trivial changes (1)
- crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js
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**/.changeset/*.md
📄 CodeRabbit inference engine (CONTRIBUTING.md)
Changeset descriptions should be user-facing, use past tense for actions taken (e.g., 'Added new feature'), and present tense for Biome behavior (e.g., 'Biome now supports...'). Include issue links, rule links, and code examples where applicable.
Files:
.changeset/slick-masks-wear.md
**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
Use rustdoc inline documentation for rules, assists, and their options. Create corresponding documentation PRs for other documentation updates against thenextbranch of the website repository.
Set theversionmetadata field in linter rule implementations to'next'for newly created rules. Update this field to the new version number when releasing a minor or major version.
Files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
🧠 Learnings (31)
📚 Learning: 2025-11-24T18:03:52.013Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:03:52.013Z
Learning: Applies to **/.changeset/*.md : Changeset descriptions should be user-facing, use past tense for actions taken (e.g., 'Added new feature'), and present tense for Biome behavior (e.g., 'Biome now supports...'). Include issue links, rule links, and code examples where applicable.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-11-24T18:03:52.014Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:03:52.014Z
Learning: For bugfix/feature PRs visible to Biome toolchain users or affecting published crates, create a changeset using the `just new-changeset` command with appropriate package selection, change type (major/minor/patch), and description.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
.changeset/slick-masks-wear.mdcrates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-08-05T14:43:29.581Z
Learnt from: dyc3
Repo: biomejs/biome PR: 7081
File: packages/@biomejs/biome/configuration_schema.json:7765-7781
Timestamp: 2025-08-05T14:43:29.581Z
Learning: The file `packages/biomejs/biome/configuration_schema.json` is auto-generated and should not be manually edited or reviewed for schema issues; any changes should be made at the code generation source.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-09-25T12:32:59.003Z
Learnt from: arendjr
Repo: biomejs/biome PR: 7593
File: crates/biome_service/src/workspace/server.rs:1306-1306
Timestamp: 2025-09-25T12:32:59.003Z
Learning: In the biomejs/biome project, do not flag compilation errors during code review as they are handled by the existing test infrastructure and CI. Focus on other code quality aspects instead.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-10-25T07:02:26.457Z
Learnt from: ematipico
Repo: biomejs/biome PR: 7856
File: .changeset/yellow-crews-guess.md:1-5
Timestamp: 2025-10-25T07:02:26.457Z
Learning: The Biome documentation website uses kebab-case URL slugs for rule pages (e.g., `/linter/rules/no-continue/`), not camelCase.
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The first paragraph of rule documentation must be a single line and serves as the brief description for the rule overview page
Applied to files:
.changeset/slick-masks-wear.md
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule implementation should use 'Type Query = Ast<NodeType>' to query the AST/CST for specific node types
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Rule messages must explain to the user what the error is, why it is triggered, and what they should do to fix it
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:57.290Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_diagnostics/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:57.290Z
Learning: Diagnostic should provide a way for the user to fix the issue through log advice, diff advice, or command advice. Add the FIXABLE tag to highlight actionable hints
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rscrates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report code that can lead to runtime failures should use the 'noUnsafe<Concept>' naming convention (e.g., `noUnsafeOptionalChaining`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'let else' pattern to reduce code branching when the rule's run function returns 'Vec'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option structs must derive 'Deserializable', 'Serialize', 'Deserialize', and optionally 'JsonSchema' traits with serde attributes
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : The rule option serde configuration must include 'deny_unknown_fields' to raise errors for extraneous fields in configuration
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : The rule option serde configuration must include 'rename_all = "camelCase"' to match biome.json naming conventions
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option structs must implement the 'biome_deserialize::Merge' trait to handle merging shared and user configurations
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option fields should be wrapped in 'Option<_>' to properly track set and unset options during configuration merging
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule options must be defined in the `biome_rule_options` crate in a file matching the rule name (e.g., 'use_this_convention.rs' for rule `useThisConvention`)
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that overwhelmingly apply to a specific framework should be named using 'use<Framework>...' or 'no<Framework>...' prefix (e.g., `noVueReservedProps`)
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in documentation can use 'ignore' property to exclude snippets from automatic validation (use sparingly)
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
📚 Learning: 2025-11-21T01:10:53.036Z
Learnt from: dyc3
Repo: biomejs/biome PR: 8171
File: crates/biome_js_analyze/src/lint/nursery/no_leaked_render.rs:125-137
Timestamp: 2025-11-21T01:10:53.036Z
Learning: In the Biome codebase, each lint rule has its own options type declaration (e.g., `type Options = RuleNameOptions`) as part of the codegen process, even if the options struct is empty or unused. This is standard practice and should not be flagged as an issue.
Applied to files:
crates/biome_rule_options/src/no_return_assign.rs
🧬 Code graph analysis (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (3)
crates/biome_service/src/workspace.rs (1)
markup(1176-1178)packages/@biomejs/plugin-api/index.d.ts (1)
Severity(1-1)crates/biome_analyze/src/rule.rs (3)
sources(617-620)same(246-251)recommended(602-605)
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Contributor
Author
|
Do we want to port the behavior where multiple assignments in the same return statement each get flagged separately? The implementation would likely need to be redone, and the overhead would likely be much higher (looping through every assignments parent(s) if they are expressions or a return statement) return (a = 1, b = 2, c = 3);
^^^^^ ^^^^^ ^^^^^ |
Contributor
|
Whichever is most easy/simple to implement. If we flag the first one and bail, that's fine. If we flag all of them, that's also fine. If it proves to be annoying for users we can adjust if they complain about it. |
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🧹 Nitpick comments (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
62-69: Consider making use of options (or dropping them for now)
type Options = NoReturnAssignOptions;is declared butrunignores any configuration, so the rule’s behaviour is effectively hard‑coded.If
NoReturnAssignOptionsis currently an empty struct this is harmless, but as soon as you add fields (e.g. to mirror ESLint’s"except-parens"vs"always"), you will need to thread them throughrun. It might be worth either:
- wiring
ctx.options()into the logic now (even if only to pattern‑match and ignore), or- dropping the options type until there’s an actual knob to avoid the illusion of configurability.
You can confirm how options are typically plumbed in other rules by grepping for
type Options =andctx.options()usage in this crate.
72-90: Tighten diagnostic note wording and punctuationThe main message is clear, but the
.notetext reads as a single block with line breaks and no final punctuation:
Return statements are often considered side-effect free.\nYou likely want to do a comparison==\nOtherwise move the assignment outside of the return statementIt might be easier to read as two or three full sentences with trailing full stops, and you may want to mention
===alongside==to avoid nudging people towards loose equality.For example (tweak as you see fit):
.note(markup! { "Return statements are often considered side-effect free. " "You likely meant to use a comparison such as " <Emphasis>"===`"</Emphasis> " instead of an assignment, " "or move the assignment outside of the return statement." })
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crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs(1 hunks)
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**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
Use rustdoc inline documentation for rules, assists, and their options. Create corresponding documentation PRs for other documentation updates against thenextbranch of the website repository.
Set theversionmetadata field in linter rule implementations to'next'for newly created rules. Update this field to the new version number when releasing a minor or major version.
Files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧠 Learnings (15)
📓 Common learnings
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Rule messages must explain to the user what the error is, why it is triggered, and what they should do to fix it
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:57.290Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_diagnostics/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:57.290Z
Learning: Diagnostic should provide a way for the user to fix the issue through log advice, diff advice, or command advice. Add the FIXABLE tag to highlight actionable hints
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should use 'Type Signals = Box<[Self::State]>' instead of 'Vec<Self::State>' to report multiple diagnostics for a single query match, to save memory
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧬 Code graph analysis (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (3)
crates/biome_service/src/workspace.rs (1)
markup(1176-1178)packages/@biomejs/plugin-api/index.d.ts (1)
Severity(1-1)crates/biome_analyze/src/rule.rs (3)
sources(617-620)same(246-251)recommended(602-605)
⏰ 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). (14)
- GitHub Check: Test Node.js API
- GitHub Check: Check JS Files
- GitHub Check: Documentation
- GitHub Check: Test (depot-windows-2022-16)
- GitHub Check: Check Dependencies
- GitHub Check: Test (depot-ubuntu-24.04-arm-16)
- GitHub Check: Lint project (depot-ubuntu-24.04-arm-16)
- GitHub Check: End-to-end tests
- GitHub Check: Lint project (depot-windows-2022)
- GitHub Check: Bench (biome_js_formatter)
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- GitHub Check: Bench (biome_js_analyze)
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🔇 Additional comments (1)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (1)
10-49: Rule declaration & metadata look solidNice job wiring this up:
version: "next",language: "js",sources: &[RuleSource::Eslint("no-return-assign").same()], and explicitSeverity::Errorall line up with the contributing guidance for a new JS rule port. The docs and examples (withexpect_diagnosticon the invalid snippet) also follow the expected pattern.
when more than one assignment is found
Contributor
Author
|
Review from code rabbit led me in a direction where I was able to simplify the implementation, also allowed me to add flagging for all assignments in a return relatively easily. |
ematipico
reviewed
Nov 25, 2025
Co-authored-by: Emanuele Stoppa <[email protected]>
assignments in the same return
Contributor
Author
|
Adding tests for the missing expressions in the morning 🫡 |
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crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js.snapis excluded by!**/*.snapand included by**crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.ts.snapis excluded by!**/*.snapand included by**
📒 Files selected for processing (3)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js(1 hunks)crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.ts(1 hunks)
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📓 Path-based instructions (1)
**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
Use rustdoc inline documentation for rules, assists, and their options. Create corresponding documentation PRs for other documentation updates against thenextbranch of the website repository.
Set theversionmetadata field in linter rule implementations to'next'for newly created rules. Update this field to the new version number when releasing a minor or major version.
Files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧠 Learnings (25)
📓 Common learnings
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule implementation should use 'Type Query = Ast<NodeType>' to query the AST/CST for specific node types
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Rule messages must explain to the user what the error is, why it is triggered, and what they should do to fix it
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:57.290Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_diagnostics/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:57.290Z
Learning: Diagnostic should provide a way for the user to fix the issue through log advice, diff advice, or command advice. Add the FIXABLE tag to highlight actionable hints
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should only have severity set to 'error' if they report hard errors, dangerous code, or accessibility issues; use 'warn' for possibly erroneous code; use 'info' for stylistic suggestions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-21T01:10:53.036Z
Learnt from: dyc3
Repo: biomejs/biome PR: 8171
File: crates/biome_js_analyze/src/lint/nursery/no_leaked_render.rs:125-137
Timestamp: 2025-11-21T01:10:53.036Z
Learning: In the Biome codebase, each lint rule has its own options type declaration (e.g., `type Options = RuleNameOptions`) as part of the codegen process, even if the options struct is empty or unused. This is standard practice and should not be flagged as an issue.
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'let else' pattern to reduce code branching when the rule's run function returns 'Vec'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report code that can lead to runtime failures should use the 'noUnsafe<Concept>' naming convention (e.g., `noUnsafeOptionalChaining`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option fields should be wrapped in 'Option<_>' to properly track set and unset options during configuration merging
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that check computations always evaluated to the same value should use the 'noConstant<Concept>' naming convention (e.g., `noConstantMathMinMaxClamp`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should use 'Type Signals = Box<[Self::State]>' instead of 'Vec<Self::State>' to report multiple diagnostics for a single query match, to save memory
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should use the semantic query 'Type Query = Semantic<NodeType>' to access semantic information like bindings and references
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/tests/specs/**/*.{js,ts,tsx,jsx,json,css,graphql} : Test files should use 'invalid' or 'valid' prefixes to indicate whether they contain code reported by the rule
Applied to files:
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.tscrates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/tests/specs/**/*.{js,ts,tsx,jsx,json,css,graphql} : Test files for rules should be placed inside 'tests/specs/' directory organized by group and rule name (e.g., 'tests/specs/nursery/myRuleName/')
Applied to files:
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.tscrates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js
🧬 Code graph analysis (1)
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.ts (1)
crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js (1)
f(3-3)
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🔇 Additional comments (3)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (1)
60-68: Implementation looks solid.The rule correctly uses
Semantic<AnyReturn>query and returns multiple signals viaVec<TextRange>. Therun_optionshelper keeps the mainrunfunction clean.crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.ts (1)
1-16: Good TypeScript-specific coverage.These test cases exercise assignments wrapped in TypeScript type assertions (
as,!,satisfies, and angle-bracket syntax). This ensures the rule's preorder traversal correctly handles TS-specific AST nodes.crates/biome_js_analyze/tests/specs/nursery/noReturnAssign/invalid.js (1)
1-110: Comprehensive test coverage.Excellent breadth covering arrow functions, sequence expressions, ternaries, logical/nullish operators, unary expressions, array literals, function calls, member access, and JSX attributes. This addresses the prior feedback about missing nested expression types.
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♻️ Duplicate comments (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
46-53: Clarify behaviour vs ESLint’sexcept-parensdefault and options.At the moment the rule unconditionally reports any
JsAssignmentExpressionunder a return expression, so something likereturn (a = 1);will still be flagged, while ESLint’sno-return-assigndefaults toexcept-parens. Given you exposeNoReturnAssignOptionsand advertiseRuleSource::Eslint("no-return-assign").same(), it’d be good to either (a) wire the options throughrun_optionsso anexceptParens/alwaysmode actually affects traversal, or (b) explicitly decide that Biome follows the"always"variant and relax the “same” claim / docs accordingly. Based on learnings, rules ported from other ecosystems should keep thesourcesmetadata in sync with their real behaviour.
9-9: Traversal still risks missing nested assignments under non-expression wrappers.The current preorder walk skips any subtree whose root is not an
AnyJsExpression:let is_expression = AnyJsExpression::can_cast(node.kind()); if !is_expression { iter.skip_subtree(); }That likely means assignments in places like call arguments, array/object elements, or other list/auxiliary nodes (which are not themselves expressions) will be pruned before reaching their inner
JsAssignmentExpression, e.g.return foo((a = 1));orreturn [a = 1];. You can simplify this and close the gap by just walking all descendants and filtering byJsAssignmentExpression:-use biome_rowan::{AstNode, TextRange, WalkEvent, declare_node_union}; +use biome_rowan::{AstNode, TextRange, declare_node_union}; @@ -fn traverse_expression(root: &AnyJsExpression) -> Vec<TextRange> { - let mut signal = Vec::new(); - let mut iter = root.syntax().preorder(); - - while let Some(event) = iter.next() { - if let WalkEvent::Enter(node) = event { - if JsAssignmentExpression::can_cast(node.kind()) { - signal.push(node.text_range()); - } - - let is_expression = AnyJsExpression::can_cast(node.kind()); - - if !is_expression { - iter.skip_subtree(); - } - } - } - signal -} +fn traverse_expression(root: &AnyJsExpression) -> Vec<TextRange> { + let mut signal = Vec::new(); + for node in root.syntax().descendants() { + if JsAssignmentExpression::can_cast(node.kind()) { + signal.push(node.text_range()); + } + } + signal +}This matches the pattern used in other rules and ensures you don’t have to reason about every intermediate wrapper node.
Also applies to: 99-116
🧹 Nitpick comments (2)
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs (2)
60-64: Signals type:Vecis fine, considerBox<[State]>if you want to follow the guide.Using
Vec<TextRange>is perfectly serviceable here, and a maintainer has already noted that vectors are supported for multiple signals. If you want to align strictly with the contribution guide’s memory‑saving pattern, you could switch totype Signals = Box<[Self::State]>, but I’d treat that as a micro‑optimisation, not a blocker.
89-97: Options are currently unused in the rule logic.
NoReturnAssigndeclarestype Options = NoReturnAssignOptions, butrun_optionsnever inspectsctx.options(). IfNoReturnAssignOptionsis still an empty struct this is fine; otherwise, any configuration (e.g. a futureexcept_parens/alwaysmode) will be silently ignored. Might be worth either wiring options in now or leaving a short comment/TODO so future readers know this is intentional.
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**/*.rs
📄 CodeRabbit inference engine (CONTRIBUTING.md)
**/*.rs: Use the Rustdbg!()macro for debugging output during test execution, and pass the--show-outputflag tocargo testto display debug output.
Use snapshot testing with theinstacrate for testing in Rust projects. Accept or reject snapshots usingcargo insta accept,cargo insta reject, orcargo insta review.
Write doc comments as doc tests in Rust using code blocks with assertions that will be executed during the testing phase.
Use rustdoc inline documentation for rules, assists, and their options. Create corresponding documentation PRs for other documentation updates against thenextbranch of the website repository.
Set theversionmetadata field in linter rule implementations to'next'for newly created rules. Update this field to the new version number when releasing a minor or major version.
Files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
🧠 Learnings (28)
📓 Common learnings
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules ported from other ecosystems should include a 'sources' field in the 'declare_lint_rule!' macro with RuleSource metadata (e.g., '::ESLint')
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'language' field in 'declare_lint_rule!' should be set to the specific JavaScript dialect (jsx, ts, tsx) if the rule only applies to that dialect, otherwise use 'js'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should be implemented with the 'impl Rule for RuleName' trait, including 'run' function that returns signals and optional 'diagnostic' and 'action' functions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : The 'declare_lint_rule!' macro must include a 'version' field set to 'next' to allow flexibility for the actual release version
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that provide code actions must declare a 'fix_kind' field in the 'declare_lint_rule!' macro with either 'FixKind::Safe' or 'FixKind::Unsafe'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules can declare 'domains' field in 'declare_lint_rule!' to specify which domain(s) they belong to (e.g., RuleDomain::Test for testing rules)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Deprecated rules must include a 'deprecated' field in the 'declare_lint_rule!' macro with the reason for deprecation
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that ban functions or variables should use the semantic model to check if the variable is global before reporting, to avoid false positives on locally redeclared variables
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report empty code should use the 'noEmpty<Concept>' naming convention (e.g., `noEmptyBlockStatements`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule implementation should use 'Type Query = Ast<NodeType>' to query the AST/CST for specific node types
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Rule messages must explain to the user what the error is, why it is triggered, and what they should do to fix it
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:57.290Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_diagnostics/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:57.290Z
Learning: Diagnostic should provide a way for the user to fix the issue through log advice, diff advice, or command advice. Add the FIXABLE tag to highlight actionable hints
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should only have severity set to 'error' if they report hard errors, dangerous code, or accessibility issues; use 'warn' for possibly erroneous code; use 'info' for stylistic suggestions
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-21T01:10:53.036Z
Learnt from: dyc3
Repo: biomejs/biome PR: 8171
File: crates/biome_js_analyze/src/lint/nursery/no_leaked_render.rs:125-137
Timestamp: 2025-11-21T01:10:53.036Z
Learning: In the Biome codebase, each lint rule has its own options type declaration (e.g., `type Options = RuleNameOptions`) as part of the codegen process, even if the options struct is empty or unused. This is standard practice and should not be flagged as an issue.
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'let else' pattern to reduce code branching when the rule's run function returns 'Vec'
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that report code that can lead to runtime failures should use the 'noUnsafe<Concept>' naming convention (e.g., `noUnsafeOptionalChaining`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_rule_options/lib/**/*.rs : Rule option fields should be wrapped in 'Option<_>' to properly track set and unset options during configuration merging
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules that check computations always evaluated to the same value should use the 'noConstant<Concept>' naming convention (e.g., `noConstantMathMinMaxClamp`)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should use 'Type Signals = Box<[Self::State]>' instead of 'Vec<Self::State>' to report multiple diagnostics for a single query match, to save memory
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:05:27.784Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_js_formatter/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:05:27.784Z
Learning: Applies to crates/biome_js_formatter/**/*.rs : Use the `dbg_write!` macro to debug formatter output instead of other logging methods
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:05:27.784Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_js_formatter/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:05:27.784Z
Learning: Applies to crates/biome_js_formatter/**/*.rs : Do not attempt to 'fix' the code; if a token/node is known to be mandatory but is missing, return `None` instead
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in documentation marked with 'expect_diagnostic' must emit exactly one diagnostic for the build system to generate it automatically
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Avoid deep indentation in rule implementations by using Rust helper functions like 'map', 'filter', and 'and_then' instead of nested if-let statements
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Use 'declare_node_union!' macro to query multiple node types at once instead of repeating rule implementations for similar nodes
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rule names should follow the 'no<Concept>' prefix when a rule's sole intention is to forbid a single concept (e.g., `noDebugger` for disallowing debugger statements)
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Code blocks in rule documentation must specify a language and use 'expect_diagnostic' property for invalid snippets that should emit exactly one diagnostic
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
📚 Learning: 2025-11-24T18:04:42.146Z
Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_analyze/CONTRIBUTING.md:0-0
Timestamp: 2025-11-24T18:04:42.146Z
Learning: Applies to crates/biome_analyze/**/biome_*_analyze/lib/src/**/!(mod).rs : Rules should use the semantic query 'Type Query = Semantic<NodeType>' to access semantic information like bindings and references
Applied to files:
crates/biome_js_analyze/src/lint/nursery/no_return_assign.rs
⏰ 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). (14)
- GitHub Check: End-to-end tests
- GitHub Check: Test (depot-ubuntu-24.04-arm-16)
- GitHub Check: Test (depot-windows-2022-16)
- GitHub Check: Lint project (depot-ubuntu-24.04-arm-16)
- GitHub Check: Lint project (depot-windows-2022)
- GitHub Check: Documentation
- GitHub Check: Check Dependencies
- GitHub Check: Check JS Files
- GitHub Check: Test Node.js API
- GitHub Check: Bench (biome_js_analyze)
- GitHub Check: Bench (biome_js_formatter)
- GitHub Check: Bench (biome_js_parser)
- GitHub Check: Bench (biome_configuration)
- GitHub Check: autofix
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Summary
Port no-return-assign from ESLint
Closes #8199
Test Plan
Snapshot tests in specs/nursery/noReturnAssign
Docs