oxc-project/oxc · error · OxcDiagnostic

The '__proto__' property is deprecated

Error message

The '__proto__' property is deprecated

What it means

Lint diagnostic from eslint/no-proto: the deprecated __proto__ property was accessed (via dot access or computed '__proto__'). It is a legacy Annex-B feature whose behavior varies across environments; the static Object helpers are the standard replacements named in the help text.

Source

Thrown at crates/oxc_linter/src/rules/eslint/no_proto.rs:8

use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::{GetSpan, Span};

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

fn no_proto_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("The '__proto__' property is deprecated")
        .with_help("use `Object.getPrototypeOf` and `Object.setPrototypeOf` instead.")
        .with_label(span)
}

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

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Disallow the use of the `__proto__` property.
    ///
    /// ### Why is this bad?
    ///
    /// The `__proto__` property has been deprecated as of ECMAScript 3.1 and
    /// shouldn’t be used in new code. Use `Object.getPrototypeOf` and
    /// `Object.setPrototypeOf` instead.
    ///

View on GitHub (pinned to e1e7af627c)

Solutions

1. Use Object.getPrototypeOf(obj) to read the prototype
2. Use Object.setPrototypeOf(obj, proto) or Object.create(proto) to set it

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/eslint/no_proto.rs:8 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/31a6a448aecce142. Report an issue: GitHub.