diff --git a/src/contrib/msc/core/utils.cc b/src/contrib/msc/core/utils.cc
index 38f355bfe2b10..66f26bd1ebeea 100644
--- a/src/contrib/msc/core/utils.cc
+++ b/src/contrib/msc/core/utils.cc
@@ -84,7 +84,10 @@ bool StringUtils::EndsWith(const String& src_string, const String& sub_string) {
   const std::string& src_cstring = src_string;
   const std::string& sub_cstring = sub_string;
   int pos = src_cstring.rfind(sub_cstring);
-  return pos == src_cstring.size() - sub_cstring.size();
+  if (pos < 0) {
+    return false;
+  }
+  return static_cast<size_t>(pos) == src_cstring.size() - sub_cstring.size();
 }
 
 const Array<String> StringUtils::Split(const String& src_string, const String& sep) {