error[E0277]: the trait bound `Bar: Hash` is not satisfied --> $DIR/issue-21160.rs:8:12 | LL | #[derive(Hash)] | ---- in this derive macro expansion LL | struct Foo(Bar); | ^^^ the trait `Hash` is not implemented for `Bar` | = note: this error originates in the derive macro `Hash` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider annotating `Bar` with `#[derive(Hash)]` | LL + #[derive(Hash)] LL | struct Bar; | error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.