[lacampbell]

So rust traits are effectively/functionally abstract classes with restricted functionality and a different implementation?

[steveklabnik]

Sort of. The closest thing in C++ would be concepts. That is, even using traits in this way is the minority case; they're more usually used for monomorphized, statically dispatched code.

But, given the case where you want dynamic dispatch, then in a sense, they are, yes.

[lacampbell]

Right. I suppose in Rust you generally use variants and pattern matching when dynamic dispatching is required.

[steveklabnik]

You could, but that requires that you know all of the variants ahead of time. The advantage of trait objects is that you don't have to.

It really just depends on what exactly you're trying to do.