error[E0277]: the trait bound `(): std::error::Error` is not satisfied --> $DIR/coerce-issue-49593-box-never.rs:18:5 | LL | Box::<_ /* ! */>::new(x) | ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()` | = note: required for the cast from `Box<()>` to `Box<(dyn std::error::Error + 'static)>` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0277`.