From fa7400a08d9c69559712268633a902682da7de97 Mon Sep 17 00:00:00 2001
From: camc314 <18101008+camc314@users.noreply.github.com>
Date: Mon, 15 Sep 2025 02:12:44 +0000
Subject: [PATCH] fix(linter/no-undef): false positive with `arguments` in
 functions (#13763)

fixes #13762
---
 .../oxc_linter/src/rules/eslint/no_undef.rs   | 19 +++++++++++++++++++
 .../src/snapshots/eslint_no_undef.snap        | 12 ++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/crates/oxc_linter/src/rules/eslint/no_undef.rs b/crates/oxc_linter/src/rules/eslint/no_undef.rs
index 53b967c40730e..aa330ca607672 100644
--- a/crates/oxc_linter/src/rules/eslint/no_undef.rs
+++ b/crates/oxc_linter/src/rules/eslint/no_undef.rs
@@ -67,6 +67,17 @@ impl Rule for NoUndef {
                     continue;
                 }
 
+                // Skip reporting error for 'arguments' if it's in a function scope
+                if name == "arguments"
+                    && ctx
+                        .scoping()
+                        .scope_ancestors(ctx.nodes().get_node(reference.node_id()).scope_id())
+                        .map(|id| ctx.scoping().scope_flags(id))
+                        .any(|scope_flags| scope_flags.is_function() && !scope_flags.is_arrow())
+                {
+                    continue;
+                }
+
                 let node = ctx.nodes().get_node(reference.node_id());
                 if !self.type_of && has_typeof_operator(node, ctx) {
                     continue;
@@ -168,6 +179,10 @@ fn test() {
         ("class C { static { a; function a() {} } }", None, None),
         ("String;Array;Boolean;", None, None),
         ("[Float16Array, Iterator]", None, None), // es2025
+        // arguments should not be reported in regular functions
+        ("function test() { return arguments; }", None, None),
+        ("var fn = function() { return arguments[0]; };", None, None),
+        ("const obj = { method() { return arguments.length; } };", None, None),
         // ("AsyncDisposableStack; DisposableStack; SuppressedError", None, None), / es2026
         ("function resolve<T>(path: string): T { return { path } as T; }", None, None),
         ("let xyz: NodeListOf<HTMLElement>", None, None),
@@ -210,6 +225,10 @@ fn test() {
         ("toString()", None, None),
         ("hasOwnProperty()", None, None),
         ("export class Foo{ bar: notDefined; }; const t = r + 1;", None, None),
+        // arguments should be reported in arrow functions (they don't have their own arguments)
+        ("const arrow = () => arguments;", None, None),
+        // arguments outside functions should be reported
+        ("var a = arguments;", None, None),
     ];
 
     Tester::new(NoUndef::NAME, NoUndef::PLUGIN, pass, fail).test_and_snapshot();
diff --git a/crates/oxc_linter/src/snapshots/eslint_no_undef.snap b/crates/oxc_linter/src/snapshots/eslint_no_undef.snap
index ca433726ec138..442014791b6be 100644
--- a/crates/oxc_linter/src/snapshots/eslint_no_undef.snap
+++ b/crates/oxc_linter/src/snapshots/eslint_no_undef.snap
@@ -174,3 +174,15 @@ source: crates/oxc_linter/src/tester.rs
  1 │ export class Foo{ bar: notDefined; }; const t = r + 1;
    ·                                                 ─
    ╰────
+
+  ⚠ eslint(no-undef): 'arguments' is not defined.
+   ╭─[no_undef.tsx:1:21]
+ 1 │ const arrow = () => arguments;
+   ·                     ─────────
+   ╰────
+
+  ⚠ eslint(no-undef): 'arguments' is not defined.
+   ╭─[no_undef.tsx:1:9]
+ 1 │ var a = arguments;
+   ·         ─────────
+   ╰────