From 3ac7fb9f6cda300df1523bdf3eb0499a727834df Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Sat, 28 Nov 2020 19:17:33 +0000
Subject: [PATCH] LibJS: Disallow 'with' statement in strict mode

---
 Libraries/LibJS/Parser.cpp          | 2 ++
 Libraries/LibJS/Tests/with-basic.js | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/Libraries/LibJS/Parser.cpp b/Libraries/LibJS/Parser.cpp
index 1596e64651..457e189011 100644
--- a/Libraries/LibJS/Parser.cpp
+++ b/Libraries/LibJS/Parser.cpp
@@ -328,6 +328,8 @@ NonnullRefPtr<Statement> Parser::parse_statement()
     case TokenType::While:
         return parse_while_statement();
     case TokenType::With:
+        if (m_parser_state.m_strict_mode)
+            syntax_error("'with' statement not allowed in strict mode");
         return parse_with_statement();
     case TokenType::Debugger:
         return parse_debugger_statement();
diff --git a/Libraries/LibJS/Tests/with-basic.js b/Libraries/LibJS/Tests/with-basic.js
index a5bdbf4e41..a1029ef621 100644
--- a/Libraries/LibJS/Tests/with-basic.js
+++ b/Libraries/LibJS/Tests/with-basic.js
@@ -18,3 +18,7 @@ test("basic with statement functionality", () => {
 
     expect(bar).toBe(99);
 });
+
+test("syntax error in strict mode", () => {
+    expect("'use strict'; with (foo) {}").not.toEval();
+});