> criticizing using unsafe in rust and comparing that to C++ In that comment I was mostly criticizing the amount of code. That code doesn’t need to be written

> criticizing using unsafe in rust and comparing that to C++ In that comment I was mostly criticizing the amount of code. That code doesn’t need to be written in C++. std::list has stable iterators so you can put list iterators to the hash map. This way LRU structure becomes a trivially simple wrapper over std::list and std::unordered_map containers. Note how Rust developers implemented custom linked list on top of raw pointers, doing manual memory management with Box::into_raw(Box::new(Node::new(k, v))) C++ implementation doesn’t need a single new/delete, hence much safer than unsafe rust. LRU cache is simple, not too hard to implement correctly in C++ just because it’s very few lines of code. > it's just that no compiler besides rust will warn you that recursive data structures are hard In GC languages like C# or Java it’s both easy and safe. In C++ they can be challenging to implement correctly, but because it’s all unsafe, I get huge amount of help from all levels of the stack. OS debugger, C runtime, C++ standard library, compilers, they all evolved for decades trying to improve life of developers like me writing unsafe programs which use raw pointers. You can implement a recursive data structure without a single new/delete, relying on standard collections for memory management. It doesn’t guarantee pointer safety just like unsafe Rust doesn’t, but at least no need to worry about memory leaks.