warning: unexpected `cfg` condition value: (none)
  --> $DIR/concat-values.rs:5:7
   |
LL | #[cfg(my_cfg)]
   |       ^^^^^^
   |
   = note: expected values for `my_cfg` are: `bar`, `foo`
   = note: `#[warn(unexpected_cfgs)]` on by default

warning: unexpected `cfg` condition value: `unk`
  --> $DIR/concat-values.rs:9:7
   |
LL | #[cfg(my_cfg = "unk")]
   |       ^^^^^^^^^^^^^^
   |
   = note: expected values for `my_cfg` are: `bar`, `foo`

warning: 2 warnings emitted