oxc-project/oxc · error · OxcDiagnostic

Do not use chained assignment

Error message

Do not use chained assignment

What it means

Lint diagnostic from eslint/no-multi-assign: an assignment expression is chained (a = b = c). Chained assignment makes the intermediate value flow hard to follow and frequently hides unintended sharing of references.

Source

Thrown at crates/oxc_linter/src/rules/eslint/no_multi_assign.rs:15

use oxc_ast::{AstKind, ast::Expression};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::Span;
use schemars::JsonSchema;
use serde::Deserialize;

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

fn no_multi_assign_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Do not use chained assignment")
        .with_help("Separate each assignment into its own statement")
        .with_label(span)
}

#[derive(Debug, Default, Clone, JsonSchema, Deserialize)]
#[serde(rename_all = "camelCase", default, deny_unknown_fields)]
pub struct NoMultiAssign {
    /// When set to `true`, the rule allows chains that don't include initializing a variable in a declaration or initializing a class field.
    ///
    /// Examples of **correct** code for this option set to `true`:
    /// ```js
    /// let a;
    /// let b;
    /// a = b = "baz";
    ///
    /// const x = {};
    /// const y = {};
    /// x.one = y.one = 1;

View on GitHub (pinned to e1e7af627c)

Solutions

1. Split the chain into separate assignment statements
2. Initialize each variable with its own expression

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/eslint/no_multi_assign.rs:15 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/cb1c675a7c37a666. Report an issue: GitHub.