warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes --> $DIR/object-safety.rs:5:12 | LL | #![feature(async_fn_in_trait)] | ^^^^^^^^^^^^^^^^^ | = note: see issue #91611 for more information = note: `#[warn(incomplete_features)]` on by default error[E0038]: the trait `Foo` cannot be made into an object --> $DIR/object-safety.rs:13:12 | LL | let x: &dyn Foo = todo!(); | ^^^^^^^^ `Foo` cannot be made into an object | note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit --> $DIR/object-safety.rs:9:14 | LL | trait Foo { | --- this trait cannot be made into an object... LL | async fn foo(&self); | ^^^ ...because method `foo` is `async` = help: consider moving `foo` to another trait error: aborting due to previous error; 1 warning emitted For more information about this error, try `rustc --explain E0038`.