| `#[track_caller]` requires functions to have the `"Rust"` ABI for implicitly | |
| receiving caller location. See [RFC 2091] for details on this and other | |
| restrictions. | |
| Erroneous code example: | |
| ```compile_fail,E0737 | |
| #[track_caller] | |
| extern "C" fn foo() {} | |
| ``` | |
| [RFC 2091]: https://github.com/rust-lang/rfcs/blob/master/text/2091-inline-semantic.md |