warning: the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes --> $DIR/no-unsize-coerce-dyn-trait.rs:1:12 | LL | #![feature(dyn_star)] | ^^^^^^^^ | = note: see issue #102425 for more information = note: `#[warn(incomplete_features)]` on by default error[E0308]: mismatched types --> $DIR/no-unsize-coerce-dyn-trait.rs:11:26 | LL | let y: Box = x; | ----------- ^ expected trait `B`, found trait `A` | | | expected due to this | = note: expected struct `Box` found struct `Box` error: aborting due to 1 previous error; 1 warning emitted For more information about this error, try `rustc --explain E0308`.