Decide on name for derive(SmartPtr)

[traviscross]

We need to resolve the open question on:

• RFC: #[derive(SmartPointer)] rfcs#3621

...regarding what name to use.

Tracking:

• Tracking Issue for derive(SmartPointer) #123430

[ChrisDenton]

I'll say I don't like the term "smart pointer" in Rust. It has a more specific meaning in C++ but porting that terminology over to Rust has been less than smooth. Like the Deref docs still imply that anything implementing the Deref trait is a "smart pointer" which is a bit of stretch on its own. But now #[derive(SmartPtr)] doesn't imply Deref and everything gets even more muddy.

I'd rather we use terms we can fully define without confusion. This feels similar to the "object safe" debate in that one aspect.

[Darksonn]

One option is to name it in relation to what it enables. For example: #[derive(DynamicDispatch)] or #[derive(DynamicPtr)].

@rustbot label F-derive_smart_pointer