From 373307db5b4401b950a45cefc0ba7eba95f912b1 Mon Sep 17 00:00:00 2001
From: Andreas Kling <andreas@ladybird.org>
Date: Sat, 26 Apr 2025 11:57:34 +0200
Subject: [PATCH] LibJS: Mark `arguments` local as initialized after creating
 it

This avoids emitting an unnecessary TDZ check for the first time we
access the arguments object.
---
 Libraries/LibJS/Bytecode/Generator.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Libraries/LibJS/Bytecode/Generator.cpp b/Libraries/LibJS/Bytecode/Generator.cpp
index 207a5f3094b..f2f3a368d0f 100644
--- a/Libraries/LibJS/Bytecode/Generator.cpp
+++ b/Libraries/LibJS/Bytecode/Generator.cpp
@@ -65,6 +65,9 @@ CodeGenerationErrorOr<void> Generator::emit_function_declaration_instantiation(E
         } else {
             emit<Op::CreateArguments>(dst, Op::CreateArguments::Kind::Mapped, function.is_strict_mode());
         }
+
+        if (local_var_index.has_value())
+            set_local_initialized(Identifier::Local::variable(local_var_index.value()));
     }
 
     auto const& formal_parameters = function.formal_parameters();