| //@ proc-macro: test-macros.rs |
| //@ proc-macro: extra-empty-derive.rs |
| //@ check-pass |
| |
| #[macro_use(Empty)] |
| extern crate test_macros; |
| #[macro_use(Empty2)] |
| extern crate extra_empty_derive; |
| |
| // Testing the behavior of derive attributes with helpers that share the same name. |
| // |
| // Normally if the first derive below were absent the call to #[empty_helper] before it it |
| // introduced by its own derive would produce a future incompat error. |
| // |
| // With the extra derive also introducing that attribute in advanced the warning gets supressed. |
| // Demonstrates a lack of identity to helper attributes, the compiler does not track which derive |
| // introduced a helper, just that a derive introduced the helper. |
| #[derive(Empty)] |
| #[empty_helper] |
| #[derive(Empty2)] |
| struct S; |
| |
| fn main() {} |
