oxc-project/oxc · error · OxcDiagnostic

Prefer omitting the catch binding parameter if it is unused

Error message

Prefer omitting the catch binding parameter if it is unused

What it means

Diagnostic from the unicorn/prefer-optional-catch-binding lint rule. It fires when a `try`/`catch` declares a catch binding parameter (e.g. `catch (error)`) that is never referenced in the catch body; ES2019 allows omitting it entirely (`catch { ... }`). The flagged input is the unused binding pattern's span. It is a lint suggestion, not a runtime error.

Source

Thrown at crates/oxc_linter/src/rules/unicorn/prefer_optional_catch_binding.rs:9

use oxc_ast::{AstKind, ast::BindingPattern};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::{GetSpan, Span};

use crate::{AstNode, context::LintContext, rule::Rule};

fn prefer_optional_catch_binding_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Prefer omitting the catch binding parameter if it is unused")
        .with_label(span)
}

#[derive(Debug, Default, Clone)]
pub struct PreferOptionalCatchBinding;

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Prefers omitting the catch binding parameter if it is unused.
    ///
    /// ### Why is this bad?
    ///
    /// It is unnecessary to bind the error to a variable if it is not used.
    ///
    /// ### Examples
    ///
    /// Examples of **incorrect** code for this rule:

View on GitHub (pinned to e1e7af627c)

Solutions

1. Remove the unused catch parameter: write `catch {` instead of `catch (error) {`
2. Apply the rule's auto-fix
3. If the error is needed later, actually use the binding instead of removing it

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/unicorn/prefer_optional_catch_binding.rs:9 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/2984c3513530a8f8. Report an issue: GitHub.