From b914680f0c94e4547c4aaea25bc34b364a726dcf Mon Sep 17 00:00:00 2001
From: Luke Wilde <lukew@serenityos.org>
Date: Fri, 25 Nov 2022 23:14:27 +0000
Subject: [PATCH] LibJS/Bytecode: Make `yield` by itself yield undefined

---
 Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
index edfcd642fc..9c8534a08e 100644
--- a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
+++ b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
@@ -1600,6 +1600,8 @@ Bytecode::CodeGenerationErrorOr<void> YieldExpression::generate_bytecode(Bytecod
 
     if (m_argument)
         TRY(m_argument->generate_bytecode(generator));
+    else
+        generator.emit<Bytecode::Op::LoadImmediate>(js_undefined());
 
     auto& continuation_block = generator.make_block();
     generator.emit<Bytecode::Op::Yield>(Bytecode::Label { continuation_block });