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`.