error: expected `:`, found `}` --> $DIR/derive-bad.rs:6:10 | LL | #[derive(A)] | ^ | | | expected `:` | while parsing this struct | = note: this error originates in the derive macro `A` (in Nightly builds, run with -Z macro-backtrace for more info) error: proc-macro derive produced unparsable tokens --> $DIR/derive-bad.rs:6:10 | LL | #[derive(A)] | ^ error[E0428]: the name `A` is defined multiple times --> $DIR/derive-bad.rs:9:1 | LL | #[derive(A)] | - previous definition of the type `A` here ... LL | struct A; | ^^^^^^^^^ `A` redefined here | = note: `A` must be defined only once in the type namespace of this module error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0428`.