In file included from /in/driver/main.cpp:5:0:
/in/hashtable.hpp: In instantiation of 'Value& HashTable<Key, Value, Hash, KeyEqual>::operator[](const Key&) [with Key = int; Value = int; Hash = std::hash<int>; KeyEqual = std::equal_to<int>]':
/in/driver/main.cpp:129:94:   required from here
/in/hashtable.hpp:398:14: error: variable 'bucketIndexIt' set but not used [-Werror=unused-but-set-variable]
         auto bucketIndexIt = it.bucketIt;
              ^~~~~~~~~~~~~
/in/hashtable.hpp: In member function 'bool HashTable<Key, Value, Hash, KeyEqual>::insert(const HashTable<Key, Value, Hash, KeyEqual>::Iterator&, const Key&, const Value&) [with Key = int; Value = int; Hash = std::hash<int>; KeyEqual = std::equal_to<int>]':
/in/hashtable.hpp:322:5: error: control reaches end of non-void function [-Werror=return-type]
     }
     ^
cc1plus: all warnings being treated as errors