One of the common pitfalls I've seen in my time is someone writing a language they are familiar with in a language that just doesn't fit; trying to apply idioms that flow well with one language to another language where that's just not a good way to achieve the same ends. An example I've seen a lot is a C thinker writing C++ classes with an init() function; sure, it works, but the C++ way is to do that in constructor…
The worst pitfall is Rust references == pointers. They are implemented as pointers, but their role is to give temporary (often exclusive) access that is restricted to a statically know scope, which is pretty specific and fits only some uses of some pointers/C++ references. In C++ pointers typically mean avoiding copying, but Rust references avoid storing/keeping the data. When these goals don't overlap, people get st…
You could have a vector of references to heap allocated data, as long as the references were parametrized by the same lifetime. You might do this if implementing a tree iterator using a vector as a stack, for instance. That goes beyond a statically known scope. But implementing a mutable iterator the same way would require a stack of mutable pointers (and therefore unsafe code whenever you dereference them), since mutable references have to be unique. That does seem like a bad limitation.