error[E0277]: `Superset` cannot be safely transmuted into `Subset` in the defining scope of `assert::Context`. --> $DIR/should_reject_contraction.rs:35:41 | LL | assert::is_transmutable::(); | ^^^^^^ `Superset` cannot be safely transmuted into `Subset` in the defining scope of `assert::Context`. | = help: the trait `BikeshedIntrinsicFrom` is not implemented for `Subset` note: required by a bound in `is_transmutable` --> $DIR/should_reject_contraction.rs:13:14 | LL | pub fn is_transmutable() | --------------- required by a bound in this function LL | where LL | Dst: BikeshedIntrinsicFrom | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable` error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.