Suppose that I am trying to make a function like:

func(iterator: impl IntoIterator<Item = T>)

I think this works with func(vec), but not func(&vec), which is fine, but what if I want it to work with both? Assume T implements Copy. So I could write two versions of the function,

func_ref(iterator: impl IntoIterator<Item = &T>) {
    let vec = iterator.map(|t| *t).collect::<Vec<_>>();
}

func_val(iterator: impl IntoIterator<Item = T>) {
    let vec = iterator.collect::<Vec<_>>();
}

But then maybe I would also need a &mut T version as well, and it feels like it should be able to work for anything that implements Deref<Target = T>, but I think if I try to define my own trait that’s implemented both for T and impl Deref<Target = T>, I’m going to run into the problem that theoretically T could implement Deref<Target = T> and so I can’t have conflicting implementations… So I just wonder if there’s a solution to this.