well I need to discard it?

I am not going to use that variable, you picky MSVC

src/engine/config.cpp

@@ -177,7 +177,7 @@ String DivConfig::getString(String key, String fallback) const {
 
 bool DivConfig::has(String key) {
   try {
-    conf.at(key);
+    String test=conf.at(key);
   } catch (std::out_of_range& e) {
     return false;
   }