From 2610f9e3c6118072e5758271dfa7db62a4229db8 Mon Sep 17 00:00:00 2001
From: Robert Bartlensky <rbartlensky@mozilla.com>
Date: Thu, 19 Jul 2018 11:16:42 +0100
Subject: [PATCH] Bug 1472681: Fix NULL_DEREFERENCE error in
 js/src/vm/EnvironmentObject-inl.h. r=luke

MozReview-Commit-ID: 9p8jbWeZvhg

--HG--
extra : rebase_source : 9c163c7682be1e515dea2015019799ad69fa7d94
---
 js/src/vm/EnvironmentObject-inl.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/js/src/vm/EnvironmentObject-inl.h b/js/src/vm/EnvironmentObject-inl.h
index 6c52d6ecee7b..673197d281c7 100644
--- a/js/src/vm/EnvironmentObject-inl.h
+++ b/js/src/vm/EnvironmentObject-inl.h
@@ -17,8 +17,11 @@ namespace js {
 inline LexicalEnvironmentObject&
 NearestEnclosingExtensibleLexicalEnvironment(JSObject* env)
 {
-    while (!IsExtensibleLexicalEnvironment(env))
+    MOZ_ASSERT(env);
+    while (!IsExtensibleLexicalEnvironment(env)) {
         env = env->enclosingEnvironment();
+        MOZ_ASSERT(env);
+    }
     return env->as<LexicalEnvironmentObject>();
 }