| // We should not see the unused_attributes lint fire for |
| // rustc_on_unimplemented, but with this bug we are seeing it fire (on |
| // subsequent runs) if incremental compilation is enabled. |
| |
| //@ revisions: cfail1 cfail2 |
| //@ build-pass (FIXME(62277): could be check-pass?) |
| |
| #![feature(rustc_attrs)] |
| #![deny(unused_attributes)] |
| |
| #[rustc_on_unimplemented = "invalid"] |
| trait Index<Idx: ?Sized> { |
| type Output: ?Sized; |
| fn index(&self, index: Idx) -> &Self::Output; |
| } |
| |
| #[rustc_on_unimplemented = "a usize is required to index into a slice"] |
| impl Index<usize> for [i32] { |
| type Output = i32; |
| fn index(&self, index: usize) -> &i32 { |
| &self[index] |
| } |
| } |
| |
| fn main() { |
| Index::<usize>::index(&[1, 2, 3] as &[i32], 2); |
| } |
