// aux-build:derive-b.rs #[macro_use] extern crate derive_b; #[B] //~ ERROR `B` is ambiguous #[C] //~ ERROR attribute `C` is currently unknown to the compiler #[B(D)] //~ ERROR `B` is ambiguous #[B(E = "foo")] //~ ERROR `B` is ambiguous #[B(arbitrary tokens)] //~ ERROR `B` is ambiguous #[derive(B)] struct B; fn main() {}