From b268171278682083d290e01f0df4eba12cc4fc95 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Thu, 17 Jan 2019 02:52:37 -0800
Subject: [PATCH] [coap] change assert to avoid index out-of-bounds warning
 (#3464)

---
 src/core/coap/coap_message.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/core/coap/coap_message.cpp b/src/core/coap/coap_message.cpp
index 9ed6d05df..44ea69cd7 100644
--- a/src/core/coap/coap_message.cpp
+++ b/src/core/coap/coap_message.cpp
@@ -317,8 +317,9 @@ otError Message::ParseHeader(void)
 {
     otError error = OT_ERROR_NONE;
 
-    assert(mBuffer.mHead.mData + mBuffer.mHead.mInfo.mReserved >=
-           reinterpret_cast<uint8_t *>(&GetHelpData()) + sizeof(GetHelpData()));
+    assert(mBuffer.mHead.mInfo.mReserved >=
+           sizeof(GetHelpData()) +
+               static_cast<size_t>((reinterpret_cast<uint8_t *>(&GetHelpData()) - mBuffer.mHead.mData)));
 
     memset(&GetHelpData(), 0, sizeof(GetHelpData()));