1 error[E0658]: the `#[custom_mir]` attribute is just used for the Rust test suite
2 --> $DIR/feature-gate-custom_mir.rs:5:1
4 LL | #[custom_mir(dialect = "built")]
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
7 = help: add `#![feature(custom_mir)]` to the crate attributes to enable
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0658`.