1 error[E0658]: `concat_idents` is not stable enough for use and is subject to change (see issue #29599)
2 --> $DIR/feature-gate-concat_idents.rs:5:13
4 LL | let a = concat_idents!(X, Y_1); //~ ERROR `concat_idents` is not stable
5 | ^^^^^^^^^^^^^^^^^^^^^^
7 = help: add #![feature(concat_idents)] to the crate attributes to enable
9 error[E0658]: `concat_idents` is not stable enough for use and is subject to change (see issue #29599)
10 --> $DIR/feature-gate-concat_idents.rs:6:13
12 LL | let b = concat_idents!(X, Y_2); //~ ERROR `concat_idents` is not stable
13 | ^^^^^^^^^^^^^^^^^^^^^^
15 = help: add #![feature(concat_idents)] to the crate attributes to enable
17 error: aborting due to 2 previous errors
19 For more information about this error, try `rustc --explain E0658`.