error[E0277]: the trait bound `Error: Eq` is not satisfied --> $DIR/derives-span-Eq-enum-struct-variant.rs:9:6 | LL | #[derive(Eq,PartialEq)] | -- in this derive macro expansion ... LL | x: Error | ^^^^^^^^ the trait `Eq` is not implemented for `Error` | note: required by a bound in `AssertParamIsEq` --> $SRC_DIR/core/src/cmp.rs:LL:COL = note: this error originates in the derive macro `Eq` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider annotating `Error` with `#[derive(Eq)]` | LL + #[derive(Eq)] LL | struct Error; | error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.