I think I've hit the same kind of problem once. What I learned is that true smart pointers are types that (at least in Rust) aren't really supposed to have methods on their own, to avoid this type of ambiguity during method resolution.

For example, Box<T> implements Deref so that you can conveniently use T's methods. If you look at the documentation of Box, the things you can do with the Box itself, like Box::leak, are non-method functions. This means that you always have to qualify them, like Box::leak(my_box), and thus you can't get this type of conflict.

Using Deref for types like String or Vec doesn't really fall into this category. They implement something more analogous to an "is-a relationship" in OO. Even outside of those examples, I've seen people manually implement inheritance-like behavior, using Deref to delegate to a field that stores the "base class" instance.

If you do that, you're likely to have a name conflict between the two types sooner rather than later. That's fine as long as you're aware that Rust doesn't really do overload resolution -- AFAICT, the "outer" methods always wins regardless of the arguments at the call site.