fix(linter): add help/note text to ~150 diagnostics #19135

Boshen · 2026-02-08T09:33:14Z

Summary

Closes #19121

Added .with_help() to ~150 linter diagnostics across all plugin groups (eslint, import, jest, react, typescript, unicorn, vue, promise, oxc)
Added .with_note() where explanatory context is more appropriate than actionable advice
Skipped diagnostics where the .warn() message already contains actionable guidance (e.g. "Prefer X over Y" rules)
All help messages are concise and actionable for both humans and AI code fixers

🤖 Generated with Claude Code

Closes #19121 Co-Authored-By: Claude Opus 4.6 <[email protected]>

Copilot

Pull request overview

Adds actionable with_help / contextual with_note text to many OxcDiagnostic chains across the linter rule set, and updates corresponding snapshot expectations so diagnostic output includes the new guidance (closes #19121).

Changes:

Append .with_help(...) and/or .with_note(...) to diagnostics across multiple rule plugins (eslint/import/jest/react/typescript/unicorn/vue/promise/oxc).
Refresh snapshot files to assert the new help: / note: lines in diagnostic output.
Minor refactors in a few diagnostics to conditionally add help text.

Reviewed changes

Copilot reviewed 188 out of 188 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
crates/oxc_linter/src/rules/vue/require_default_export.rs	Add help text to Vue default-export diagnostics
crates/oxc_linter/src/rules/vue/no_export_in_script_setup.rs	Add help text to Vue `<script setup>` export diagnostics
crates/oxc_linter/src/rules/vue/define_props_destructuring.rs	Add help text to defineProps destructuring diagnostics
crates/oxc_linter/src/rules/unicorn/no_unreadable_array_destructuring.rs	Add help text for unreadable array destructuring
crates/oxc_linter/src/rules/unicorn/no_typeof_undefined.rs	Add help text to typeof-undefined diagnostic
crates/oxc_linter/src/rules/unicorn/no_object_as_default_parameter.rs	Add help text for object-literal default params
crates/oxc_linter/src/rules/unicorn/no_anonymous_default_export.rs	Add help text for anonymous default exports
crates/oxc_linter/src/rules/typescript/prefer_enum_initializers.rs	Add help text for enum initializer requirement
crates/oxc_linter/src/rules/typescript/no_wrapper_object_types.rs	Add help text about using primitive types
crates/oxc_linter/src/rules/typescript/no_extra_non_null_assertion.rs	Add help text to remove extra non-null assertions
crates/oxc_linter/src/rules/typescript/no_empty_interface.rs	Add help text for empty interface diagnostics
crates/oxc_linter/src/rules/typescript/no_dynamic_delete.rs	Add help text suggesting `Reflect.deleteProperty`
crates/oxc_linter/src/rules/typescript/explicit_module_boundary_types.rs	Add help text for missing boundary types
crates/oxc_linter/src/rules/typescript/consistent_type_imports.rs	Add help text for type/value import guidance
crates/oxc_linter/src/rules/typescript/consistent_type_assertions.rs	Add help text suggesting annotation/`satisfies`
crates/oxc_linter/src/rules/typescript/ban_types.rs	Add help/note text for banned TS types diagnostics
crates/oxc_linter/src/rules/typescript/ban_ts_comment.rs	Add help text for removing/updating @ts- directives
crates/oxc_linter/src/rules/typescript/adjacent_overload_signatures.rs	Add help text to keep overloads adjacent
crates/oxc_linter/src/rules/react/style_prop_object.rs	Add help text for `style` prop object requirement
crates/oxc_linter/src/rules/react/rules_of_hooks.rs	Add help text for Rules of Hooks violations
crates/oxc_linter/src/rules/react/prefer_es6_class.rs	Add help text for `createReactClass` vs class usage
crates/oxc_linter/src/rules/react/only_export_components.rs	Add help text for fast-refresh export constraints
crates/oxc_linter/src/rules/react/no_unescaped_entities.rs	Add help text for escaping entities in JSX
crates/oxc_linter/src/rules/react/no_set_state.rs	Add help text discouraging `setState`
crates/oxc_linter/src/rules/react/no_redundant_should_component_update.rs	Add help text to remove redundant SCU
crates/oxc_linter/src/rules/react/no_namespace.rs	Add help text for disallowing namespaced JSX
crates/oxc_linter/src/rules/react/jsx_props_no_spreading.rs	Add help text for avoiding JSX prop spreading
crates/oxc_linter/src/rules/react/jsx_pascal_case.rs	Add help text for PascalCase JSX components
crates/oxc_linter/src/rules/react/jsx_no_useless_fragment.rs	Add help text for removing useless fragments
crates/oxc_linter/src/rules/react/jsx_no_undef.rs	Add help text to import/declare missing components
crates/oxc_linter/src/rules/react/jsx_no_comment_textnodes.rs	Add help text for JSX comment braces
crates/oxc_linter/src/rules/react/jsx_max_depth.rs	Add help text suggesting extracting nested JSX
crates/oxc_linter/src/rules/react/jsx_key.rs	Add help text to add `key` props
crates/oxc_linter/src/rules/react/forbid_dom_props.rs	Add help text to remove forbidden DOM props
crates/oxc_linter/src/rules/promise/valid_params.rs	Add help text for incorrect Promise method arity
crates/oxc_linter/src/rules/promise/spec_only.rs	Add help text to use standard Promise methods
crates/oxc_linter/src/rules/promise/no_multiple_resolved.rs	Add help text to early-return after resolve/reject
crates/oxc_linter/src/rules/promise/avoid_new.rs	Add help text suggesting async/await
crates/oxc_linter/src/rules/oxc/no_rest_spread_properties.rs	Add help text for avoiding object rest/spread
crates/oxc_linter/src/rules/jest/no_test_return_statement.rs	Add help text to use `await` in tests
crates/oxc_linter/src/rules/jest/no_restricted_matchers.rs	Add help text for restricted matcher chains
crates/oxc_linter/src/rules/jest/no_restricted_jest_methods.rs	Add help text for restricted jest/vi methods
crates/oxc_linter/src/rules/jest/no_hooks.rs	Add help text to use helpers instead of hooks
crates/oxc_linter/src/rules/jest/no_confusing_set_timeout.rs	Add help text for `jest.setTimeout` placement
crates/oxc_linter/src/rules/jest/no_conditional_in_test.rs	Add help text for conditionals in tests
crates/oxc_linter/src/rules/import/no_self_import.rs	Add help text for self-import removal
crates/oxc_linter/src/rules/import/no_nodejs_modules.rs	Add help text about allowlist/alternatives
crates/oxc_linter/src/rules/import/no_mutable_exports.rs	Add help text to use `const` exports
crates/oxc_linter/src/rules/import/no_default_export.rs	Add help text to prefer named exports
crates/oxc_linter/src/rules/import/no_anonymous_default_export.rs	Add help text to name default exports
crates/oxc_linter/src/rules/import/no_absolute_path.rs	Add help text to use relative paths
crates/oxc_linter/src/rules/import/namespace.rs	Add help/note text for namespace import diagnostics
crates/oxc_linter/src/rules/import/exports_last.rs	Add help text to move exports to file end
crates/oxc_linter/src/rules/import/export.rs	Add help text for export/re-export issues
crates/oxc_linter/src/rules/eslint/symbol_description.rs	Add help text to add Symbol description
crates/oxc_linter/src/rules/eslint/require_yield.rs	Add help text to add `yield`
crates/oxc_linter/src/rules/eslint/radix.rs	Add help text for parseInt radix usage
crates/oxc_linter/src/rules/eslint/prefer_promise_reject_errors.rs	Add help text to reject with Error
crates/oxc_linter/src/rules/eslint/no_useless_catch.rs	Add help text for removing redundant try/catch
crates/oxc_linter/src/rules/eslint/no_useless_backreference.rs	Add explanatory note to useless backreference diagnostics
crates/oxc_linter/src/rules/eslint/no_unused_private_class_members.rs	Add help text to remove unused private members
crates/oxc_linter/src/rules/eslint/no_unreachable.rs	Add help text to remove unreachable code
crates/oxc_linter/src/rules/eslint/no_undefined.rs	Add help text to use `void 0`
crates/oxc_linter/src/rules/eslint/no_undef.rs	Add help text to declare/fix references
crates/oxc_linter/src/rules/eslint/no_throw_literal.rs	Add help text to throw Error objects
crates/oxc_linter/src/rules/eslint/no_setter_return.rs	Add help text to remove setter return value
crates/oxc_linter/src/rules/eslint/no_self_assign.rs	Add help text to remove self-assignment
crates/oxc_linter/src/rules/eslint/no_restricted_globals.rs	Conditionally add help when no suffix guidance exists
crates/oxc_linter/src/rules/eslint/no_redeclare.rs	Add help text for redeclarations
crates/oxc_linter/src/rules/eslint/no_param_reassign.rs	Add help text to use locals instead of param reassignment
crates/oxc_linter/src/rules/eslint/no_nonoctal_decimal_escape.rs	Add help text to use Unicode escapes
crates/oxc_linter/src/rules/eslint/no_new_func.rs	Add help text to avoid Function constructor
crates/oxc_linter/src/rules/eslint/no_new.rs	Add help text to avoid `new` for side effects
crates/oxc_linter/src/rules/eslint/no_nested_ternary.rs	Add help text to refactor nested ternaries
crates/oxc_linter/src/rules/eslint/no_multi_str.rs	Add help text to use template literals/concat
crates/oxc_linter/src/rules/eslint/no_misleading_character_class.rs	Add explanatory notes about multi-code-point chars
crates/oxc_linter/src/rules/eslint/no_magic_numbers.rs	Add help text for consts / extracting constants
crates/oxc_linter/src/rules/eslint/no_loss_of_precision.rs	Add help text to use BigInt/adjust value
crates/oxc_linter/src/rules/eslint/no_lone_blocks.rs	Add help text to remove redundant blocks
crates/oxc_linter/src/rules/eslint/no_labels.rs	Add help text to use control flow statements
crates/oxc_linter/src/rules/eslint/no_label_var.rs	Add help text to rename label/variable
crates/oxc_linter/src/rules/eslint/no_global_assign.rs	Add help text to assign locally instead
crates/oxc_linter/src/rules/eslint/no_func_assign.rs	Add help text to use different variable name
crates/oxc_linter/src/rules/eslint/no_fallthrough.rs	Add help text for break/return or comment removal
crates/oxc_linter/src/rules/eslint/no_extend_native.rs	Add help text to avoid modifying native prototypes
crates/oxc_linter/src/rules/eslint/no_eval.rs	Add help text suggesting safer alternatives
crates/oxc_linter/src/rules/eslint/no_delete_var.rs	Add note about `delete` validity
crates/oxc_linter/src/rules/eslint/no_control_regex.rs	Add help text to use Unicode escapes
crates/oxc_linter/src/rules/eslint/no_constructor_return.rs	Add help text to remove constructor return value
crates/oxc_linter/src/rules/eslint/no_const_assign.rs	Add help text suggesting `let` when needed
crates/oxc_linter/src/rules/eslint/no_class_assign.rs	Add help text to use different variable name
crates/oxc_linter/src/rules/eslint/no_case_declarations.rs	Add help text to wrap case in braces
crates/oxc_linter/src/rules/eslint/no_await_in_loop.rs	Add help text suggesting Promise aggregation
crates/oxc_linter/src/rules/eslint/no_async_promise_executor.rs	Add help text to remove `async` from executor
crates/oxc_linter/src/snapshots/vue_require_default_export.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/vue_no_export_in_script_setup.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/vue_define_props_destructuring.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/unicorn_no_typeof_undefined.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/unicorn_no_object_as_default_parameter.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/typescript_prefer_enum_initializers.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/typescript_no_wrapper_object_types.snap	Snapshot updated to include updated help text
crates/oxc_linter/src/snapshots/typescript_no_extra_non_null_assertion.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/typescript_no_empty_interface.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/typescript_no_dynamic_delete.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_style_prop_object.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_prefer_es6_class.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_only_export_components.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_no_unescaped_entities.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_no_set_state.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_no_redundant_should_component_update.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_no_namespace.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_props_no_spreading.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_pascal_case.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_no_undef.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_no_comment_textnodes.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_max_depth.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_jsx_key.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/react_forbid_dom_props.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/promise_valid_params.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/promise_spec_only.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/promise_no_multiple_resolved.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/promise_avoid_new.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/oxc_no_rest_spread_properties.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/jest_no_test_return_statement.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/jest_no_restricted_matchers.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/jest_no_restricted_jest_methods.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/jest_no_hooks.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_no_nodejs_modules.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_no_mutable_exports.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_no_default_export.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_no_anonymous_default_export.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_no_absolute_path.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_exports_last.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/import_export.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_symbol_description.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_require_yield.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_radix.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_useless_catch.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_unreachable.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_restricted_globals.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_new_func.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_new.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_nested_ternary.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_multi_str.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_label_var.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_global_assign.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_func_assign.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_delete_var.snap	Snapshot updated to include new note line
crates/oxc_linter/src/snapshots/[email protected]	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_constructor_return.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_class_assign.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_case_declarations.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_await_in_loop.snap	Snapshot updated to include new help lines
crates/oxc_linter/src/snapshots/eslint_no_async_promise_executor.snap	Snapshot updated to include new help lines

Copilot · 2026-02-08T09:37:20Z

crates/oxc_linter/src/rules/import/namespace.rs

    OxcDiagnostic::warn(format!("Assignment to member of namespace {namespace_name:?}.'"))
+        .with_note("Imported namespace members are read-only.")
        .with_label(span)


Diagnostic message has a stray .' at the end ("...{namespace_name:?}.'"), which will show up in user-facing output. Remove the extra punctuation/quote so the message reads cleanly (e.g. ends with a single period).

Copilot · 2026-02-08T09:37:21Z

crates/oxc_linter/src/rules/vue/no_export_in_script_setup.rs

+    OxcDiagnostic::warn("<script setup>` cannot contain ES module exports.")
+        .with_help("Use `defineExpose` instead")
+        .with_label(span)


The warning message has mismatched backticks: "<script setup> cannot contain ES module exports."is missing the opening backtick before<script setup>. This renders oddly in diagnostics; wrap the full tag in backticks (e.g. `` <script setup>` cannot ... ``).

Copilot · 2026-02-08T09:37:21Z

crates/oxc_linter/src/rules/eslint/no_useless_backreference.rs

    match problem {
-        Problem::Nested =>OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' from within that group.")).with_label(span),
-        Problem::Disjunctive => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which is in another alternative.")).with_label(span),
-        Problem::Forward => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which appears later in the pattern.")).with_label(span),
-        Problem::Backward => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which appears before in the same lookbehind.")).with_label(span),
-        Problem::IntoNegativeLookaround => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which is in a negative lookaround.")).with_label(span),
+        Problem::Nested =>OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' from within that group.")).with_note("This backreference always matches the empty string.").with_label(span),
+        Problem::Disjunctive => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which is in another alternative.")).with_note("This backreference always matches the empty string.").with_label(span),
+        Problem::Forward => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which appears later in the pattern.")).with_note("This backreference always matches the empty string.").with_label(span),
+        Problem::Backward => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which appears before in the same lookbehind.")).with_note("This backreference always matches the empty string.").with_label(span),
+        Problem::IntoNegativeLookaround => OxcDiagnostic::warn(format!("Backreference '{back_reference}' will be ignored. It references group '{group}' which is in a negative lookaround.")).with_note("This backreference always matches the empty string.").with_label(span),


This match arm chain is not rustfmt-formatted (e.g. missing space after =>, very long single-line chains). If CI runs cargo fmt --check, this will fail; please run rustfmt and split the diagnostic builder across lines for readability.

Copilot · 2026-02-08T09:37:21Z

crates/oxc_linter/src/rules/typescript/ban_types.rs

    OxcDiagnostic::warn("'The `Object` type actually means \"any non-nullish value\"")
+        .with_help("Use `object` or define an explicit object shape.")
+        .with_note("The `Object` type includes primitives like strings and numbers, which is rarely intended.")
        .with_label(span)


The Object diagnostic message starts with an extra leading apostrophe ("'The ..."), which will appear in the user-facing output. Remove the stray ' so the message renders correctly.

codspeed-hq · 2026-02-08T09:40:32Z

Merging this PR will not alter performance

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing boshen/linter-diagnostic-help (b8e45fa) with main (7318275)}

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

camchenry · 2026-02-09T00:39:42Z

crates/oxc_linter/src/rules/eslint/no_class_assign.rs

-        assign_span.label(format!("{name} is re-assigned here")),
-    ])
+    OxcDiagnostic::warn(format!("Unexpected re-assignment of class {name}"))
+        .with_help("Use a different variable name.")


i'm not sure if this is good advice. honestly with the whole point of this rule I feel like the only advice we can give is just: don't do it? don't assign to a class?

camchenry · 2026-02-09T00:43:12Z

crates/oxc_linter/src/rules/eslint/no_control_regex.rs

    } else {
        "Unexpected control character"
    })
+    .with_help("Use a Unicode escape sequence instead.")


this doesn't actually fix the issue because we report on unicode escapes too. i think if they meant to use a control character, they should disable the rule for this line/file or the rule altogether. this isn't really any specific help I can think of

camchenry · 2026-02-09T00:46:22Z

crates/oxc_linter/src/rules/eslint/no_eval.rs

 fn no_eval_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("eval can be harmful.").with_label(span)
+    OxcDiagnostic::warn("eval can be harmful.")
+        .with_help("Use 'JSON.parse()' or a function call instead.")


Suggested change

.with_help("Use 'JSON.parse()' or a function call instead.")

.with_help("For parsing JSON, consider using 'JSON.parse()'. Otherwise, try refactoring the code to not use `eval` at all.")

camchenry · 2026-02-09T00:47:27Z

crates/oxc_linter/src/rules/eslint/no_func_assign.rs


 fn no_func_assign_diagnostic(name: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("'{name}' is a function."))
+        .with_help("Use a different variable name.")


similar to no-class-assign, I don't think this is the right help message. you just shouldn't assign to it at all really. i'm not exactly sure what to suggest.

camchenry · 2026-02-09T00:50:33Z

crates/oxc_linter/src/rules/eslint/no_labels.rs

 fn no_labels_diagnostic(message: &'static str, label_span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn(message).with_label(label_span)
+    OxcDiagnostic::warn(message)
+        .with_help("Use control flow statements instead.")


a bit vague still, could probably be more like

Suggested change

.with_help("Use control flow statements instead.")

.with_help("Use control flow statements like if/while/case/for instead.")

camchenry · 2026-02-09T00:52:10Z

crates/oxc_linter/src/rules/eslint/no_loss_of_precision.rs

 fn no_loss_of_precision_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("This number literal will lose precision at runtime.").with_label(span)
+    OxcDiagnostic::warn("This number literal will lose precision at runtime.")
+        .with_help("Use 'BigInt' or adjust the value.")


might be worth adding a note here about 9007199254740991 and Number.MAX_SAFE_INTEGER and how any number larger than that might be rounded to a different integer

camchenry · 2026-02-09T00:54:09Z

crates/oxc_linter/src/rules/eslint/no_magic_numbers.rs

+    OxcDiagnostic::warn(format!("No magic number: {raw}"))
+        .with_help("Extract into a named constant.")


the message here is also not very good:

Suggested change

OxcDiagnostic::warn(format!("No magic number: {raw}"))

.with_help("Extract into a named constant.")

OxcDiagnostic::warn(format!("The number {raw} is used, but has no name given to it."))

.with_help("Extract into a named constant.")

camchenry

@Boshen there are too many changes to review here I think. I've reviewed quite a few of these files already, and i have enough concerns as it is to say we shouldn't merge this in its current state. i think it would be easier to split this up into smaller chunks, no more than 5 or so and get more eyes on it.

camchenry · 2026-02-09T00:59:10Z

crates/oxc_linter/src/rules/eslint/no_new_func.rs

+    OxcDiagnostic::warn("The Function constructor is eval.")
+        .with_help("Use a function expression or declaration.")


there's also another PR open to address this, but we should also update the message here too

camchenry · 2026-02-09T01:01:47Z

crates/oxc_linter/src/rules/eslint/no_nonoctal_decimal_escape.rs

 fn no_nonoctal_decimal_escape_diagnostic(escape_sequence: &str, span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn(format!("Don't use '{escape_sequence}' escape sequence.")).with_label(span)
+    OxcDiagnostic::warn(format!("Don't use '{escape_sequence}' escape sequence."))
+        .with_help("Use a Unicode escape sequence instead.")


i'm not sure this is good advice either, you probably shouldn't use these at all. at best, we could recommend replacing it with how it's interpreted (\8 -> 8)?

camchenry · 2026-02-09T01:03:36Z

crates/oxc_linter/src/rules/eslint/no_self_assign.rs

+    OxcDiagnostic::warn("this expression is assigned to itself")
+        .with_help("Remove this self-assignment.")


Suggested change

OxcDiagnostic::warn("this expression is assigned to itself")

.with_help("Remove this self-assignment.")

OxcDiagnostic::warn("This expression is assigning to itself")

.with_help("Remove this expression.")

camchenry · 2026-02-09T01:04:43Z

crates/oxc_linter/src/rules/eslint/no_undef.rs

 fn no_undef_diagnostic(name: &str, span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn(format!("'{name}' is not defined.")).with_label(span)
+    OxcDiagnostic::warn(format!("'{name}' is not defined."))
+        .with_help("Declare the variable or fix the reference.")


it's probably worth mentioning this might be due to missing entries in globals too, and we might want to include a link to the oxlint docs on that

camchenry · 2026-02-09T01:07:02Z

crates/oxc_linter/src/rules/eslint/no_undefined.rs

 fn no_undefined_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected use of `undefined`").with_label(span)
+    OxcDiagnostic::warn("Unexpected use of `undefined`")
+        .with_help("Use 'void 0' instead.")


this is probably wrong quite often, it depends on the context. for example you can't replace const undefined = "foo"; with const void 0 = "foo";. we could at least say like: consider using void 0 for expressions, and consider using a different name otherwise

fix(linter): add help/note text to ~150 diagnostics

b7be328

Closes #19121 Co-Authored-By: Claude Opus 4.6 <[email protected]>

Boshen requested a review from camc314 as a code owner February 8, 2026 09:33

Copilot AI review requested due to automatic review settings February 8, 2026 09:33

github-actions bot added A-linter Area - Linter C-bug Category - Bug labels Feb 8, 2026

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Boshen requested a review from camchenry February 8, 2026 09:40

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camchenry reviewed Feb 9, 2026

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Boshen assigned connorshea and camc314 Feb 9, 2026

Boshen marked this pull request as draft February 9, 2026 04:33

	.with_help("Use 'JSON.parse()' or a function call instead.")
	.with_help("For parsing JSON, consider using 'JSON.parse()'. Otherwise, try refactoring the code to not use `eval` at all.")

	.with_help("Use control flow statements instead.")
	.with_help("Use control flow statements like if/while/case/for instead.")

		OxcDiagnostic::warn(format!("No magic number: {raw}"))
		.with_help("Extract into a named constant.")

		OxcDiagnostic::warn("The Function constructor is eval.")
		.with_help("Use a function expression or declaration.")

		OxcDiagnostic::warn("this expression is assigned to itself")
		.with_help("Remove this self-assignment.")

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fix(linter): add help/note text to ~150 diagnostics #19135

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fix(linter): add help/note text to ~150 diagnostics #19135

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codspeed-hq bot commented Feb 8, 2026 •

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