oxc-project/oxc · error · OxcDiagnostic

`{obj_name}` is not a function and cannot be called

Error message

`{obj_name}` is not a function and cannot be called

What it means

Lint diagnostic from eslint/no-obj-calls (check_callee): the callee of a call expression resolves to a known non-callable global object such as Math, JSON, or Reflect. Calling it throws 'TypeError: X is not a function' at runtime; the diagnostic's help states exactly that.

Source

Thrown at crates/oxc_linter/src/rules/eslint/no_obj_calls.rs:16

use oxc_allocator::ArenaBox;
use oxc_ast::{
    AstKind,
    ast::{Expression, IdentifierReference, MemberExpression, match_member_expression},
};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_semantic::AstNode;
use oxc_span::Span;

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

const GLOBAL_THIS: &str = "globalThis";

fn no_obj_calls_diagnostic(obj_name: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("`{obj_name}` is not a function and cannot be called"))
        .with_help("This call will throw a TypeError at runtime.")
        .with_label(span)
}

#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub struct NoObjCalls;

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Disallow calling some global objects as functions.
    ///
    /// This rule can be disabled for TypeScript code, as the TypeScript compiler
    /// enforces this check.
    ///
    /// ### Why is this bad?
    ///
    /// Some global objects are not intended to be called as functions.

View on GitHub (pinned to e1e7af627c)

Solutions

1. Use the intended method on the object, e.g. Math.max(...), JSON.parse(...)
2. Fix the typo if a function was intended (e.g. JSON vs JSONp)

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/eslint/no_obj_calls.rs:16 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/19b09a2574bec5ab. Report an issue: GitHub.