Tracking issue for the bare_trait_object compatibility lint

[Manishearth]

In Rust 2018, things like Box<Trait> will become deprecated in favor of using Box<dyn Trait>

Eventually (not the Rust 2018 epoch), using Trait as a type may be removed entirely, or mean impl Trait instead. To mitigate this breakage in future epochs, please replace cases where Trait is used as a type with dyn Trait.

[Manishearth]

This lint isn't actually a future compat lint, closing the tracking issue.