From b14032bbfa8d49f4a342c0fc88eb5c6ed8c43395 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Wed, 5 Jul 2023 14:07:20 +0200
Subject: [PATCH] LibJS/Bytecode: Leave `for in` and `for of` with right
 completion value

14 new passes on test262. :^)
---
 Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
index ec1ee2d2fc..348fcd9c9b 100644
--- a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
+++ b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
@@ -2705,9 +2705,15 @@ static Bytecode::CodeGenerationErrorOr<void> for_in_of_body_evaluation(Bytecode:
     //         1. Assert: iterationKind is iterate.
     //         2. Return ? IteratorClose(iteratorRecord, status).
 
+    generator.emit<Bytecode::Op::LoadImmediate>(js_undefined());
+
     // l. Let result be the result of evaluating stmt.
     TRY(body.generate_bytecode(generator));
 
+    auto result_register = generator.allocate_register();
+    if (!generator.is_current_block_terminated())
+        generator.emit<Bytecode::Op::Store>(result_register);
+
     // m. Set the running execution context's LexicalEnvironment to oldEnv.
     if (has_lexical_binding)
         generator.end_variable_scope();
@@ -2730,6 +2736,7 @@ static Bytecode::CodeGenerationErrorOr<void> for_in_of_body_evaluation(Bytecode:
         generator.emit<Bytecode::Op::Jump>().set_targets(Bytecode::Label { loop_update }, {});
 
     generator.switch_to_basic_block(loop_end);
+    generator.emit<Bytecode::Op::Load>(result_register);
     return {};
 }