| error[E0658]: `cfg(sanitize)` is experimental and subject to change | 
 |   --> $DIR/doc-cfg-unstable.rs:5:11 | 
 |    | | 
 | LL | #[doc(cfg(sanitize = "thread"))] | 
 |    |           ^^^^^^^^^^^^^^^^^^^ | 
 |    | | 
 |    = note: see issue #39699 <https://github.com/rust-lang/rust/issues/39699> for more information | 
 |    = help: add `#![feature(cfg_sanitize)]` to the crate attributes to enable | 
 |    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date | 
 |  | 
 | error: aborting due to 1 previous error | 
 |  | 
 | For more information about this error, try `rustc --explain E0658`. |