core-quality-unused-import

Pack: core-quality Default severity: MAJOR Languages: TypeScript, JavaScript Lifecycle: experimental Confidence: 0.9

What it catches

Import bindings that are never referenced in the file:

• import Foo from 'x' — default binding flagged when unused.
• import * as Foo from 'x' — namespace binding flagged when unused.
• import { A, B } from 'x' — each named binding checked independently; one finding per unused name.

Side-effect imports (import 'x') have no binding and are never flagged.

Why this matters for vibe-coded apps

Every unused import is:

1. Bundle bloat — most bundlers tree-shake well, but import * as defeats it, and CJS-shape modules drag in side effects.
2. Supply-chain surface — a CVE in lodaash only matters because someone imported lodaash. Slopsquatting attacks ride this exact lever.
3. Misleading to agents — the next AI looking at the file may believe useState is in use somewhere it isn't, and propose changes that depend on that ghost.

Example — flagged

import { useState } from 'react';                 // ← flag (named)
import lodash from 'lodash';                      // ← flag (default)
import * as helpers from './helpers';             // ← flag (namespace)

import { partial, unused } from './partial';      // ← flag `unused` only
export function take(): unknown {
  return partial();
}

Example — not flagged

import { useState } from 'react';
export function counter(): number {
  const [n, setN] = useState(0);
  setN(n + 1);
  return n;
}

// Type-only usage counts as a use.
import type { Result } from './result';
export function ok<T>(value: T): Result<T> { … }

// Renamed binding — local alias is what's used.
import { compute as compute2 } from './compute';
export function go(): number { return compute2(); }

// Side-effect-only import: no binding, never flagged.
import './styles.css';

Suggested fix

• Named import is unused — drop just that name from the brace list. Don't delete the whole line if other names are still in use.
• Default / namespace import is unused — delete the whole import line.
• Import was kept for side effects — convert to side-effect form: import 'foo';.

Suppressing

// Reason: re-exported via barrel even though this file does not reference it.
// codemore-ignore-next-line: core-quality-unused-import
import { kept } from './kept';
export { kept };

The directive must be on the line immediately before the target. If you put a comment between them, the directive suppresses the comment instead.

Implementation

AST-based. Reuses the same identifier-reference pre-pass as core-quality-unused-variable. Then walks every ImportDeclaration: checks the default name, each named-import specifier, and any namespace import independently against the reference set, emitting one hit per unused binding. Side-effect-only imports (no importClause) are skipped by construction.

Source: `shared/packs/core-quality/core-quality-unused-import.ts` Fixtures: `corpus/rules/core-quality-unused-import/`