What about a use case where you want to use a hashmap to store 3 different types of keys independently. Would you implement the hashmap once and just store a un

What about a use case where you want to use a hashmap to store 3 different types of keys independently. Would you implement the hashmap once and just store a union of the 3 types and then assert the correct type has been stored at each call site? Would you implement the hash map 3 different times? What happens if later on, some years later, the code needs to change and another type needs to be stored in a map? Generalizing a map via void pointers is the most pragmatic solution.