I'm stuck trying to decide whether to implement my own hash table, or use an additional and unnecessary level of pointers with unordered_map
C++17 gave us std::vector, std::list and std::forward_list of incomplete types (HOW DID IT TAKE THAT LONG), but from what I can tell, not even C++26 will have std::unordered_map of incomplete types :(
Of course in #Rust, vectors and hash maps and everything else just works with recursive types no problem