diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 439af6022..90a22b877 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -8745,7 +8745,7 @@ void Tokenizer::simplifyNamespaceStd()
     };
     static const std::set<std::string> stdFunctions(stdFunctions_, stdFunctions_+sizeof(stdFunctions_)/sizeof(*stdFunctions_));
 
-    for (Token* tok = Token::findsimplematch(list.front(), "using namespace std ;"); tok; tok = tok->next()) {
+    for (const Token* tok = Token::findsimplematch(list.front(), "using namespace std ;"); tok; tok = tok->next()) {
         bool insert = false;
         if (Token::Match(tok, "%var% (") && !Token::Match(tok->previous(), ".|::") && stdFunctions.find(tok->str()) != stdFunctions.end())
             insert = true;