[dyn] is already [implemented in nightly][iss], so maybe `dyn` should be highlighted somehow in the playpen? [dyn]:https://github.com/rust-lang/rfcs/pull/2113 [iss]:https://github.com/rust-lang/rust/issues/44662
dyn is already implemented in nightly, so maybe
dynshould be highlighted somehow in the playpen?