1 error[E0658]: use of unstable library feature 'concat_bytes'
2 --> $DIR/feature-gate-concat_bytes.rs:2:13
4 LL | let a = concat_bytes!(b'A', b"BC");
7 = note: see issue #87555 <https://github.com/rust-lang/rust/issues/87555> for more information
8 = help: add `#![feature(concat_bytes)]` to the crate attributes to enable
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0658`.