error[E0277]: `Rc` cannot be sent between threads safely --> $DIR/cross-crate.rs:14:17 | LL | use_alias::>(); | ^^^^^^^ `Rc` cannot be sent between threads safely | = help: the trait `Send` is not implemented for `Rc` = note: required because of the requirements on the impl of `SendSync` for `Rc` note: required by a bound in `use_alias` --> $DIR/cross-crate.rs:10:17 | LL | fn use_alias() {} | ^^^^^^^^ required by this bound in `use_alias` error[E0277]: `Rc` cannot be shared between threads safely --> $DIR/cross-crate.rs:14:17 | LL | use_alias::>(); | ^^^^^^^ `Rc` cannot be shared between threads safely | = help: the trait `Sync` is not implemented for `Rc` = note: required because of the requirements on the impl of `SendSync` for `Rc` note: required by a bound in `use_alias` --> $DIR/cross-crate.rs:10:17 | LL | fn use_alias() {} | ^^^^^^^^ required by this bound in `use_alias` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0277`.