@soulsource @anlumo dude your whole code is UB. A reference & means that the data behind it never changes while any reference exists, allowing multiple pointers to point at it at the same time (aliasing); whereas a mutable reference &mut means that the data behind may only be read or written by that pointer, i.e. multiple pointers (aliasing) can't exist. The compiler uses this to optimize code and remove stuff that you promise never happens. Always use miri, and go read the nomicon.