warning: `auto` traits are unstable | |
--> $DIR/pre-cfg.rs:4:1 | |
| | |
LL | auto trait Foo {} | |
| ^^^^ | |
| | |
= note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information | |
= help: add `#![feature(auto_traits)]` to the crate attributes to enable | |
= warning: unstable syntax can change at any point in the future, causing a hard error! | |
= note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860> | |
warning: 1 warning emitted | |