Announcing `async fn` and return-position `impl Trait` in traits | Rust Blog
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  • sugar_in_your_tea@sh.itjust.works
    11·
    11 months ago

    -> impl Trait in public traits

    That’s a bummer. This works:

    trait Base {
  fn op(&self);
}
trait Child : Base {
  fn other_op(&self);
}

trait A {
  fn some_fn(val: impl Base) {
    val.op();
  }
}

fn some_fn(val: impl Child) {
  val.op();
  val.other_op();
}

    So it seems like returning an impl Child in a trait that binds impl Base should also work.