1 error[E0321]: cross-crate traits with a default impl, like `Send`, can only be implemented for a struct/enum type, not `&'static Foo`
2 --> $DIR/empty_span.rs:7:5
4 LL | unsafe impl Send for &'static Foo { }
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't implement cross-crate trait with a default impl for non-struct/enum type
7 error: aborting due to previous error
9 For more information about this error, try `rustc --explain E0321`.