From 015a0e90bcbd5c4093650917d1373d211c086a41 Mon Sep 17 00:00:00 2001
From: Max Schaefer <max@semmle.com>
Date: Mon, 29 Sep 2014 10:16:22 +0100
Subject: [PATCH] Only accept for-of loops in ECMA6 mode.

---
 acorn.js      | 4 ++--
 test/tests.js | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/acorn.js b/acorn.js
index aafc34d2bd..8d4760d520 100644
--- a/acorn.js
+++ b/acorn.js
@@ -1584,13 +1584,13 @@
       next();
       parseVar(init, true, varKind);
       finishNode(init, "VariableDeclaration");
-      if ((tokType === _in || (tokType === _name && tokVal === "of")) && init.declarations.length === 1 &&
+      if ((tokType === _in || (options.ecmaVersion >= 6 && tokType === _name && tokVal === "of")) && init.declarations.length === 1 &&
           !(isLet && init.declarations[0].init))
         return parseForIn(node, init);
       return parseFor(node, init);
     }
     var init = parseExpression(false, true);
-    if (tokType === _in || (tokType === _name && tokVal === "of")) {
+    if (tokType === _in || (options.ecmaVersion >= 6 && tokType === _name && tokVal === "of")) {
       checkLVal(init);
       return parseForIn(node, init);
     }
diff --git a/test/tests.js b/test/tests.js
index 936e73a5fb..40069ee697 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -28594,6 +28594,10 @@ testFail("const a;", "Unexpected token (1:7)", {ecmaVersion: 6});
 
 testFail("for(const x = 0;;);", "Unexpected token (1:4)", {ecmaVersion: 6});
 
+testFail("for(x of a);", "Unexpected token (1:6)");
+
+testFail("for(var x of a);", "Unexpected token (1:10)");
+
 // Assertion Tests
 (function() {
   var actualComments = [],