1 error[E0658]: type ascription is experimental
2 --> $DIR/feature-gate-type_ascription.rs:5:13
7 = note: for more information, see https://github.com/rust-lang/rust/issues/23416
8 = help: add `#![feature(type_ascription)]` to the crate attributes to enable
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0658`.