diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
index b32eb0d80..16542edd8 100644
--- a/lib/checkclass.cpp
+++ b/lib/checkclass.cpp
@@ -2021,10 +2021,9 @@ bool CheckClass::isConstMemberFunc(const Scope *scope, const Token *tok) const
     return false;
 }
 
-namespace {
-    // The container contains the STL types whose operator[] is not a const.
-    const std::set<std::string> stl_containers_not_const = { "map", "unordered_map" };
-}
+
+// The container contains the STL types whose operator[] is not a const.
+static const std::set<std::string> stl_containers_not_const = { "map", "unordered_map" };
 
 bool CheckClass::checkConstFunc(const Scope *scope, const Function *func, bool& memberAccessed) const
 {