error[E0658]: `dyn*` trait objects are experimental --> $DIR/gated-span.rs:5:4 | LL | t!(dyn* Send); | ^^^^ | = note: see issue #102425 for more information = help: add `#![feature(dyn_star)]` to the crate attributes to enable error: aborting due to previous error For more information about this error, try `rustc --explain E0658`.