error[E0277]: `Error` doesn't implement `std::fmt::Debug` --> $DIR/derives-span-Debug-tuple-struct.rs:8:5 | LL | Error | ^^^^^ `Error` cannot be formatted using `{:?}` | = help: the trait `std::fmt::Debug` is not implemented for `Error` = note: add `#[derive(Debug)]` or manually implement `std::fmt::Debug` = note: required because of the requirements on the impl of `std::fmt::Debug` for `&Error` = note: required for the cast to the object type `dyn std::fmt::Debug` = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.