Error code E0543
The note
value is missing in a stability attribute.
Erroneous code example:
#![allow(unused)] #![feature(staged_api)] #![allow(internal_features)] #![stable(since = "1.0.0", feature = "test")] fn main() { #[stable(since = "0.1.0", feature = "_deprecated_fn")] #[deprecated( since = "1.0.0" )] // invalid fn _deprecated_fn() {} }
To fix this issue, you need to provide the note
field. Example:
#![allow(unused)] #![feature(staged_api)] #![allow(internal_features)] #![stable(since = "1.0.0", feature = "test")] fn main() { #[stable(since = "0.1.0", feature = "_deprecated_fn")] #[deprecated( since = "1.0.0", note = "explanation for deprecation" )] // ok! fn _deprecated_fn() {} }
See the How Rust is Made and “Nightly Rust” appendix of the Book and the Stability attributes section of the Rustc Dev Guide for more details.