fix(linter/no-use-before-define): honor ignoreTypeReferences when value and type name collisions

[Dimava]

Prevent no-use-before-define from reporting unresolved references in initializers when ignoreTypeReferences is enabled, so type assertions like x as foo are not treated as value self-references.

Made-with: Cursor

fixes #19743

fix(linter): honor ignoreTypeReferences when value and type names collide

Summary

• Fixes a no-use-before-define false positive in TypeScript when ignoreTypeReferences: true.
• Prevents unresolved type-only initializer references from being treated as value self-references.
• Adds a regression test for a global type foo and local variable foo with x as foo.
• Fixed by GPT-5.3 Codex in Cursor.

Bug Repro

Config:

{
  "rules": {
    "no-use-before-define": ["error", { "ignoreTypeReferences": true, "variables": true }]
  }
}

Input:

declare global {
  type foo = string
}

export function fn(x: unknown) {
  const foo = x as foo
  return foo
}

Expected: no lint error (as foo is type-only).
Actual before fix: 'foo' was used before it was defined.

Root Cause

In the unresolved-reference branch of no-use-before-define, the initializer self-reference fallback path ran without first honoring ignoreTypeReferences.
That allowed unresolved type-only references (like as foo) to be interpreted like value self-references (let foo = foo).

Fix

• In unresolved-symbol handling, return early when:
  • ignoreTypeReferences is enabled, and
  • the reference is type-only (is_type_reference(...)).
• Keep existing initializer self-reference behavior for value references unchanged.
• Add a regression case to the TypeScript ESLint test set.

Files Changed

• crates/oxc_linter/src/rules/eslint/no_use_before_define.rs

Validation

• Confirmed regression behavior: test fails without the fix and passes with the fix restored.
• cargo test -p oxc_linter no_use_before_define::test_typescript_eslint
• cargo lint -- --deny warnings

Prerequisites Checklist

• Branch created from origin/main
• Change is scoped to one rule and includes regression test
• Root cause identified and fixed (no workaround)
• No unrelated files included in this change
• Full lint suite passed (cargo lint -- --deny warnings)
• Targeted rule tests passed

Test Plan

• Run cargo test -p oxc_linter no_use_before_define::test_typescript_eslint
• Verify new test case passes with fix
• Verify same case fails when guard is temporarily removed (done locally)
• Run full lint (cargo lint -- --deny warnings)

Notes for Reviewers

• Behavior change is intentionally narrow: unresolved type-only references are ignored only when ignoreTypeReferences is true.
• Value-reference ordering checks and initializer self-reference detection remain unchanged.

[camc314]

Thank yoU!

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 51 skipped benchmarks¹

---

_{Comparing Dimava:fix/no-use-before-define-ignore-type-ref-shadowing (017ba9f) with main (e2c5c63)}

Footnotes

1. 51 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩